Revistas
Revista:
NANOMATERIALS
ISSN:
2079-4991
Año:
2023
Vol.:
13
N°:
1
Págs.:
3
A new material composed of a kaolin base with silver nanoparticles (AgNPs) attached to its surface was developed, as an alternative to antibiotics used as supplements in animal feed. As part of its safety assessment, an in vivo geno-toxicological evaluation of this material was conducted in rats. First, a preliminary dose finding study was carried out to decide the doses to be tested in the main study: 50, 300 and 2000 mg/kg b.w. For the main study, a combined strategy composed of the MN test (TG 474) and the comet assay (TG 489), integrated in a repeated dose 28-day oral toxicity study (TG 407), was performed. A No Observed Adverse Effect Level (NOAEL) of 2000 mg of the silver-kaolin formulation/kg b.w. by oral route, for 28 days, was determined. The silver-kaolin formulation did not induce micronuclei in bone marrow, or DNA strand breaks (SBs) or alkali labile sites (ALS) in liver, spleen, kidney or duodenum at any dose. The modified Fpg comet assay did not reveal oxidized bases in the same tissues at the dose of 2000 mg/kg b.w. Silver was quantified by ICP-MS in all the target organs, confirming the negative results obtained under these conditions.
Revista:
ACTA TROPICA
ISSN:
0001-706X
Año:
2021
Vol.:
215
Págs.:
105801
Compounds 1 and 2 (selenocyanate and diselenide derivatives, respectively) were evaluated for their potential use in vivo against visceral leishmaniasis (VL). Both entities showed low cytoxicity in vitro in Vero and Caco-2 cell lines. However, the compounds were not suitable for their oral administration, since they exhibited poor values of intestinal permeability in vitro. Microsomal stability assays did not show any metabolite for compound 1 after 120 min, whereas 2 was highly metabolized by the enzyme CYP450. Thus, the in vivo efficacy of compound 1 was assessed in a murine model of L. infantum VL. The daily i.v. administration of 1 mg/kg of compound 1 during 5 consecutive days reduced parasite load in liver, spleen and bone marrow (99.2%, 91.7% and 61.4%, respectively) compared to non-treated mice. To the best of our knowledge, this is the first time that a selenium compound has been tested in vivo against VL. Thus, this work evidences the possible usefulness of selenocyanate derivatives for the treatment of this disease.
Revista:
JOURNAL OF CLEANER PRODUCTION
ISSN:
0959-6526
The aim of this study is to develop new air lime mortars with enhanced photocatalytic depolluting and self-cleaning abilities. Nanosilica, as pozzolanic mineral admixture, was used to improve the strength of mortars, whereas nanotitania (TiO2) was added to impart photocatalytic properties. At the same time, five different dispersing admixtures -superplasticizers- were added in bulk to the mortars to enhance the photocatalytic activity by reducing the rate of charge carrier recombination. Four polycarboxylate-based derivatives and a polynaphthalene sulfonate were tested aiming to achieve an efficient charge separation. In order to increase the lasting of the mortars subjected to water movements, sodium oleate was also added as a water repellent agent. Since the photoinduced hydrophilicity, responsible for the self-cleaning effect, might be affected by the water repellent, the compatibility between this admixture and the photocatalytic performance of the nanotitania was also investigated. Results showed that photocatalytic activity was improved due to the action of the superplasticizers as indicated by an average 33% increase of NO degradation, which is significant to the depolluting activity of these mortars. Furthermore, these mortars also showed a greatly reduced release of intermediate toxic compounds, mainly NO2: the selectivity factor (NOx/NO) reached values up to 87%.
Revista:
CONSTRUCTION AND BUILDING MATERIALS
ISSN:
0950-0618
Año:
2021
Vol.:
271
Págs.:
121887
The present work presents focuses on the use of different admixtures for the development of rendering lime-based mortars with improved adhesion and durability, as well as reduction of cracking. To this aim, combinations of an adhesion improver (ethylene-vinyl acetate copolymer, EVA), a water repellent agent (sodium oleate), a viscosity enhancer (a starch derivative) and a mineral admixture (pozzolanic addition of nanosilica or metakaolin) were tested. The renders were applied on four different substrates (sandstone, limestone, granite and brick) to assess their performance.
The influence of the admixtures¿ combination on fluidity, stiffening time, adhesion, cracking, compressive strength, pore structure, frost resistance and durability against magnesium sulfate attack was evaluated. The EVA admixture was seen to enhance the adhesion when used in combination with oleate, metakaolin and starch. This combination also led to a minimized cracking. Opposite trends between adhesion and cracking were observed as a function of the porosity of the substrates and of the presence of small-sized capillary pores.
The interferences with the carbonation accounted for the drops observed in compressive strength for the nanosilica-free tested renders; nanosilica-containing renders showed good compressive performance, due to the filling effect of the admixture and to the C-S-H formation.
Revista:
APPLIED CLAY SCIENCE
ISSN:
0169-1317
Año:
2021
Vol.:
212
Págs.:
106218
This study analyses how a Mg-Al-Hydrotalcite with carbonate in the interlayer influences the hydration of mortar allowing the management of lead waste (solid or liquid) in a cement-based material. First, the compatibility of hydrotalcite with the cementitious matrix was studied through heat of hydration, workability, consistency, compressive strength and mineralogical phase formation. The changes produced by the incorporation of hydrotalcite were not drastic and the compatibility with the cement was verified. Lead was added in oxide and nitrate form to mortar with or without hydrotalcite and the same properties were evaluated, including a leaching test. The incorporation of lead delayed the hydration, this effect being increased by the hydrotalcite, which happened in the first instants of hydration. The addition of hydrotalcite counteracted the negative effect of lead in compressive strength values. The interaction between the hydrotalcite and the lead waste was favoured by the formation of plumbites under the pH conditions of cement hydration. Consequently, this interaction would seem to be superficial. The lead leaching decreased to values included in the "Non-Hazardous" limit of the environmental classification, very close to "Inert". All mortars were produced by two mixing procedures to establish differences. When hydrotalcite was included, the compressive strength was higher in the second procedure and lead leaching showed better behaviour in the first procedure.
Revista:
ACS INFECTIOUS DISEASES
ISSN:
2373-8227
Año:
2021
Vol.:
7
N°:
12
Págs.:
3197 - 3209
Leishmaniasis urgently needs new oral treatments, as it is one of the most important neglected tropical diseases that affects people with poor resources. The drug discovery pipeline for oral administration currently discards entities with poor aqueous solubility and permeability (class IV compounds in the Biopharmaceutical Classification System, BCS) such as the diselenide 2m, a trypanothione reductase (TR) inhibitor. This work was assisted by glyceryl palmitostearate and diethylene glycol monoethyl ether-based nanostructured lipid carriers (NLC) to render 2m bioavailable and effective after its oral administration. The loading of 2m in NLC drastically enhanced its intestinal permeability and provided plasmatic levels higher than its effective concentration (IC50). In L. infantum-infected BALB/c mice, 2m-NLC reduced the parasite burden in the spleen, liver, and bone marrow by at least 95% after 5 doses, demonstrating similar efficacy as intravenous Fungizone. Overall, compound 2m and its formulation merit further investigation as an oral treatment for visceral leishmaniasis.
Revista:
POLYMERS
ISSN:
2073-4360
Año:
2020
Vol.:
12
N°:
4
Págs.:
887
This paper presents the experimental procedure to develop air lime-based injection grouts including polymeric superplasticizers, a water repellent agent and pozzolanic agents as additives. Research focuses on the development of grouts to improve various characteristics simultaneously combining different additions and admixtures. Aiming to improve the injectability of the grouts, in this study different polymeric superplasticizers were added, namely polycarboxylated-ether derivative (PCE), polynaphthalene sulfonate (PNS) and condensate of melamine-formaldehyde sulfonate (SMFC). Sodium oleate was also used as a water repellent agent to reduce the water absorption. The enhancement of the strength and setting time was intended by using microsilica and metakaolin as pozzolanic mineral additions. Compatibility between the different admixtures and action mechanism of the different polymers were studied by means of zeta potential and adsorption isotherms measurements. Diverse grout mixtures were produced and investigated assessing their injectability, fluidity, stability, compressive strength, hydrophobicity and durability. This research leads to several suitable mixtures produced by using more than one component to enhance efficiency and to provide better performance of grouts. According to the results, the grout composed of air lime, metakaolin, sodium oleate and PCE was found the most effective composition improving the mechanical strength, injectability and hydrophobicity.
Revista:
INTERNATIONAL JOURNAL OF ARCHITECTURAL HERITAGE
ISSN:
1558-3058
Año:
2020
Vol.:
14
N°:
7
Págs.:
1008 - 1029
Unique multifunctional coatings, comprising a 3D superhydrophobic agent and two nanostructured photocatalysts (solar-light sensitive 50/50 and 10/90 TiO2-ZnO nano-heterostructures), compatible with the inorganic substrates of the Built Heritage, have been designed.
The synthesized nanoparticles showed an enhanced photocatalytic activity (tested by NO degradation) as compared with the raw TiO2 and ZnO materials.
Dispersing agents were used to optimize the coatings, avoiding agglomeration of the photocatalytic nanoparticles and increasing the stability of the suspensions. Four distinct dispersions were optimized and applied as coatings onto stony materials used in the Built Heritage, such as sandstone, lime mortar, granite and limestone. Their effectiveness was assessed by assessing hydrophobicity of the surfaces (static water contact angle), photocatalytic activity and self-cleaning as well as water vapour permeability of the treated specimens. These transparent coatings demonstrated high compatibility with the construction materials of the Architectural Heritage and showed a synergistic effect rendering a minimized water absorption, self-cleaning ability evidenced by the reduced adsorption of soiling deposits and a reasonable degradation of any trace that might be adsorbed, as well as a protecting hydrophobic environment for the photocatalyst.
Revista:
JOURNAL OF CLINICAL LIPIDOLOGY
ISSN:
1933-2874
Revista:
PHARMACEUTICS
ISSN:
1999-4923
Año:
2019
Vol.:
11
N°:
11
Págs.:
607
The oral administration of dapsone (DAP) for the treatment of cutaneous leishmaniasis (CL) is effective, although serious hematological side effects limit its use. In this study, we evaluated this drug for the topical treatment of CL. As efficacy depends on potency and skin penetration, we first determined its antileishmanial activity (IC50 = 100 ¿M) and selectivity index in vitro against Leishmania major-infected macrophages. In order to evaluate the skin penetration ex vivo, we compared an O/W cream containing DAP that had been micronized with a pluronic lecithin emulgel, in which the drug was solubilized with diethylene glycol monoethyl ether. For both formulations we obtained similar low flux values that increased when the stratum corneum and the epidermis were removed. In vivo efficacy studies performed on L. major-infected BALB/c mice revealed that treatment not only failed to cure the lesions but made their evolution and appearance worse. High plasma drug levels were detected and were concomitant with anemia and iron accumulation in the spleen. This side effect was correlated with a reduction of parasite burden in this organ. Our results evidenced that DAP in these formulations does not have an adequate safety index for use in the topical therapy of CL.
Revista:
HEPATOLOGY
ISSN:
0270-9139
Año:
2019
Vol.:
70
N°:
1
Págs.:
108 - 126
Gene therapy with an adeno-associated vector (AAV) serotype 8 encoding the human ATPase copper-transporting beta polypeptide (ATP7B) complementary DNA (cDNA; AAV8¿ATP7B) is able to provide long-term copper metabolism correction in 6-week-old male Wilson disease (WD) mice. However, the size of the genome (5.2 kilobases [kb]) surpasses the optimal packaging capacity of the vector, which resulted in low-yield production; in addition, further analyses in WD female mice and in animals with a more advanced disease revealed reduced therapeutic efficacy, as compared to younger males. To improve efficacy of the treatment, an optimized shorter AAV vector was generated, in which four out of six metal¿binding domains (MBDs) were deleted from the ATP7B coding sequence, giving rise to the miniATP7B protein (delta57-486-ATP7B). In contrast to AAV8-ATP7B, AAV8-miniATP7B could be produced at high titers and was able to restore copper homeostasis in 6- and 12-week-old male and female WD mice. In addition, a recently developed synthetic AAV vector, AAVAnc80, carrying the miniATP7B gene was similarly effective at preventing liver damage, restoring copper homeostasis, and improving survival 1 year after treatment. Transduction of approximately 20% of hepatocytes was sufficient to normalize copper homeostasis, suggesting that corrected hepatocytes are acting as a sink to eliminate excess of copper.
Revista:
POLYMERS
ISSN:
2073-4360
Año:
2018
Vol.:
10
N°:
8
Págs.:
824
A new range of grouts prepared by air lime and metakaolin (MK) as a pozzolanic admixture has been obtained by using as dispersing agents two polymers, namely poly-naphthalene sulfonate (PNS) and lignosulfonate (LS), with the aim of improving the fluidity of the fresh grouts. Fluidity and setting times of the grouts were assessed. Differences in the molecular architecture and in the anionic charge density explained the different adsorption of the polymers and the different performance. The higher anionic charge of PNS and its linear shape explained its better adsorption and effectiveness. The pozzolanic reaction was favoured in grouts with PNS, achieving the highest values of compressive strength (4.8 MPa after 182 curing days). The addition of PNS on lime grouts slightly decreased the frost resistance of the grouts (from 24 freeze-thaw cycles for the polymer-free samples to 19 or 20 cycles with 0.5 or 1 wt % of PNS). After the magnesium sulphate attack, grouts were altered by decalcification of hydrated phases and by formation of hexahydrite and gypsum. A protective role of portlandite against magnesium sulphate attack was clearly identified. Accordingly, the polymer LS, which preserves a significant amount of Ca(OH)2, could be an alternative for the obtaining of grouts requiring high sulphate attack resistance.
Revista:
CONSTRUCTION AND BUILDING MATERIALS
ISSN:
0950-0618
Año:
2018
Vol.:
162
Págs.:
628 - 648
Coatings made with water dispersions of different nano-particles of photocatalytic additives (titania and titania doped with iron and vanadium) were prepared with diverse superplasticizers, SPs, to optimize the atmospheric NO removal efficiency when applied onto cement- and air-lime mortars. The use of different polycarboxylate-based superplasticizers (52IPEG, 23APEG and 45PC6) prevented nano-particles from agglomeration. The steric hindrance, provided by a large density and length of side chains, was ascertained as the most effective repulsion mechanism and 52IPEG was the most efficient SP. In PC- and air-lime mortars, the coatings with polycarboxylate-based SPs improved the NO removal rates as compared with the SP-free coating: an average increase of NO degradation by 15% under UV and by 76% under solar light was found. This finding was related to the drop in the agglomeration of the photocatalysts, with more exposed active sites and a decrease of the electron-hole recombination rates. Capillary water absorption and water vapour permeability values showed that the coatings did not alter the performance of the mortars. SEM examination showed that the use of SPs enhanced the distribution of the photocatalysts yielding thinner coating layers and boosting the percolation of the active material within the mortars. Accelerated weathering showed a moderate reduction of NO removal efficiency. Coating with 52IPEG was the most efficient in preserving the activity. Measurements of Ti content showed a low washout of the TiO2 nano-particles, supporting the long-run activity of these coatings.
Revista:
CONSTRUCTION AND BUILDING MATERIALS
ISSN:
0950-0618
Año:
2017
Vol.:
149
Págs.:
257 - 271
Mortars made with Portland cement, two different calcium aluminate cements and air lime were chosen to incorporate photocatalytic additives, because they have large exposed surfaces that boost the photochemical oxidation (PCO) of atmospheric pollutants such as nitrogen oxides. TiO2 as reference catalyst, and two doped titania, Fe-TiO2 and V-TiO2, which were expected to increase the sensitivity of the additives towards the visible light, were studied. Cementing matrices, particularly air lime and high alumina cement mortars, yielded significant amounts of NO removal under the three illumination conditions studied (UV, solar and visible light), with high selectivity response for NO abatement (up to 60 to 80%) and low NO2 release. The presence of calcium carbonate has been shown to have a synergistic effect, enhancing the PCO of these mortars under different light sources.
Revista:
NANOMATERIALS
ISSN:
2079-4991
Año:
2017
Vol.:
7
N°:
10
Págs.:
329
Mortars with two different binders (Portland cement (PC) and high alumina cement (HAC)) were modified upon the bulk incorporation of nano-structured photocatalytic additives (bare TiO2, and TiO2 doped with either iron (Fe-TiO2) or vanadium (V-TiO2)). Plastic and hardened state properties of these mortars were assessed in order to study the influence of these nano-additives. Water demand was increased, slightly by bare TiO2 and Fe-TiO2, and strongly by V-TiO2, in agreement with the reduction of the particle size and the tendency to agglomerate. Isothermal calorimetry showed that hydration of the cementitious matrices was accelerated due to additional nucleation sites offered by the nano-additives. TiO2 and doped TiO2 did not show pozzolanic reactivity in the binding systems. Changes in the pore size distribution, mainly the filler effect of the nano-additives, accounted for the increase in compressive strengths measured for HAC mortars. A complex microstructure was seen in calcium aluminate cement mortars, strongly dependent on the curing conditions. Fe-TiO2 was found to be homogeneously distributed whereas the tendency of V-TiO2 to agglomerate was evidenced by elemental distribution maps. Water absorption capacity was not affected by the nano-additive incorporation in HAC mortars, which is a favourable feature for the application of these mortars.
Revista:
NANOMEDICINE
ISSN:
1743-5889
Año:
2016
Vol.:
11
N°:
5
Págs.:
465 - 477
Aim: Development of EGF-liposomes (LP-EGF) for selective molecules delivery in tumors expressing EGFR. Material & methods: In vitro cellular interaction of EGF-LP and nontargeted liposomes (LP-N) was assayed at 37 and 4°C in cells expressing different EGFR levels. Receptor-mediated uptake was investigated by competition with a monoclonal antibody anti-EGFR. Selective intracellular drug delivery and efficacy was tested by oxaliplatin encapsulation. In vivo biodistribution of LP-N and LP-EGF was done in xenograft model. Results: LP-EGF was internalized by an active and selective mechanism through EGFR without receptor activation. Oxaliplatin LP-EGF decreased IC50 between 48 and 13% in cell EGFR+. LP-EGF was accumulated in tumor over 72 h postdosing, while LP-N in spleen. Conclusion: LP-EGF represents an attractive nanosystem for cancer therapy or diagnosis.
Revista:
JOURNAL OF HEPATOLOGY
ISSN:
1600-0641
Año:
2016
Vol.:
64
N°:
2
Págs.:
419-26
Our data demonstrate that AAV8-AAT-ATP7B-mediated gene therapy provides long-term correction of copper metabolism in a clinically relevant animal model of WD providing support for future translational studies.
Revista:
CEMENT AND CONCRETE RESEARCH
ISSN:
0008-8846
Año:
2016
Vol.:
81
Págs.:
1 - 15
The effect of chlorides and nitrates of Li(I), Cr(III), Zn(II), Cu(II), Pb(II) nitrate and Cr(VI) (chromate) on the early hydration of ternary cement system of calcium aluminates (CA, CA2, C12A7) was reported. Li(I) and Cr(III) caused a strong acceleration of the hydration, while Zn(II) as well as chromate gave rise to a slight acceleration. On the contrary, Pb(II) and Cu(II) retarded the hydration. A clear formation of AFm phases during the first hydration stages was found and related to the acceleration ability. Anions (nitrate or chloride as counterions or even chromate) were able to be incorporated into the interlayer space of AFm, yielding insoluble and stable compounds. A balance between the insolubility of the metal hydroxides (dependant on the low amphoteric character of the compound) and the ability of the formation of AFm hydrates seems to be very important to lean the equilibrium towards the retarding of the hydration or towards the acceleration, respectively.
Revista:
CEMENT AND CONCRETE RESEARCH
ISSN:
0008-8846
Año:
2016
Vol.:
82
Págs.:
11 - 22
Polynaphtalenesulfonate (PNS) and lignosulfonate (LS) were tested as superplasticizers in pastes and mortars of pure air lime and air lime with a pozzolanic additive, nanosilica (NS). LS showed a better plasticizing effect than PNS: the flowability of the samples with LS as well as the slump retention over time was larger. LS strongly hindered carbonation due to its ability to form Ca2+ complexes. In mortars with NS, PNS was seen to interfere with the C-S-H formation, resulting in lower mechanical strengths. Adsorption isotherms and zeta potential showed that PNS was more adsorbed than LS onto lime and C-S-H particles. PNS acted mainly through electrostatic repulsion owing to its high anionic charge density and flat adsorption. However, LS was more efficient as superplasticizer in air lime media, steric hindrance being the main mechanism responsible for avoiding flocculation. Furthermore, LS yielded high compressive strengths in mortars with NS.
Revista:
JOURNAL OF ENVIRONMENTAL MANAGEMENT
ISSN:
0301-4797
Año:
2015
Vol.:
159
Págs.:
288 - 300
Phosphate coating hazardous wastes originated from the automotive industry were efficiently encapsulated by an acid¿base reaction between phosphates present in the sludge and calcium aluminate cement, yielding very inert and stable monolithic blocks of amorphous calcium phosphate (ACP). Two different compositions of industrial sludge were characterized and loaded in ratios ranging from 10 to 50 wt.%. Setting times and compressive strengths were recorded to establish the feasibility of this method to achieve a good handling and a safe landfilling of these samples. Short solidification periods were found and leaching tests showed an excellent retention for toxic metals (Zn, Ni, Cu, Cr and Mn) and for organic matter. Retentions over 99.9% for Zn and Mn were observed even for loadings as high as 50 wt.% of the wastes. The formation of ACP phase of low porosity and high stability accounted for the effective immobilization of the hazardous components of the wastes.
Revista:
JOURNAL OF CONTROLLED RELEASE
ISSN:
0168-3659
Año:
2015
Vol.:
210
Págs.:
26 - 36
Oxaliplatin (L-OH), a platinum derivative with good tolerability is currently combined with Cetuximab (CTX), a monoclonal antibody (mAb), for the treatment of certain (wild-type KRAS) metastatic colorectal cancer (CRC) expressing epidermal growth factor receptor (EGFR).
Improvement of L-OH pharmacokinetics (PK) can be provided by its encapsulation into liposomes, allowing a more selective accumulation and delivery to the tumor. Here, we aim to associate both agents in a novel liposomal targeted therapy by linking CTX to the drug-loaded liposomes. These EGFR-targeted liposomes potentially combine the therapeutic activity and selectivity of CTX with tumor-cell delivery of L-OH in a single therapeutic approach.
L-OH liposomes carrying whole CTX or CTX-Fab¿ fragments on their surface were designed and characterized. Their functionality was tested in vitro using four human CRC cell lines, expressing different levels of EGFR to investigate the role of CTX-EGFR interactions in the cellular binding and uptake of the nanocarriers and encapsulated drug. Next, those formulations were evaluated in vivo in a colorectal cancer xenograft model with regard to tumor drug accumulation, toxicity and therapeutic activity.
In EGFR-overexpressing cell lines, intracellular drug delivery by targeted liposomes increased with receptor density reaching up to 3-fold higher levels than with non-targeted liposomes. Receptor specific uptake was demonstrated by competition with free CTX, which reduced...
Autores:
Pérez-Nicolás, M; Balbuena, J.; Cruz-Yusta, M.; et al.
Revista:
CEMENT AND CONCRETE RESEARCH
ISSN:
0008-8846
Año:
2015
Vol.:
70
Págs.:
67 - 76
Photocatalytic activity of TiO2 was studied in two types of calcium aluminate cement (CAC) under two different curing regimes. The effect of the TiO2 addition on the setting time, consistency and mechanical properties of the CACs was evaluated. The abatement of gaseous pollutants (NOx) under UV irradiation was also assessed. These cementitious matrices were found to successfully retain NO2: more abundant presence of aluminates in white cement (w-CAC, iron-lean) helped to better adsorb NO2, thus improving the conversion performance of the catalyst resulting in a larger NOx removal under UV irradiation. As evidenced by XRD, SEM, EDAX and zeta potential analyses, the presence of ferrite in dark cement (d-CAC, iron-reach) induced a certain chemical interaction with TiO2. The experimental findings suggest the formation of new iron titanate phases, namely pseudobrookite. The reduced band-gap energy of these compounds compared with that of TiO2 accounts for the photocatalytic activity of these samples.
Revista:
ANIMAL FEED SCIENCE AND TECHNOLOGY
ISSN:
0377-8401
Año:
2015
Vol.:
200
Págs.:
35 - 46
Aflatoxins (AFs) content was analyzed in bovine feedstuff from dairy farms in Spain.¿None of the samples exceeds AFB1 legislation but a high incidence (90%) was found.¿Geographical location, unlike season or feeding system, had limited influence on AFs.¿Organic homemade feedstuff showed non-detected level of AFs throughout the study.
Aflatoxins (B1, B2, G1 and G2) are produced by the fungi Aspergillus (A. flavus and A. parasiticus) in substrates used in cattle feed manufacturing. Aflatoxin M1 (AFM1) is a major metabolite of Aflatoxin B1 (AFB1) which may be present in milk from animals that consume contaminated feed. Levels of aflatoxins in 78 dairy cow feedstuff samples from 40 farms located in Navarra were determined by HPLC-FLD (High Performance Liquid Chromatography with fluorescence detection) and post-column derivatization. The influence of geographical location, season and type of feeding system on aflatoxin content was studied. The climatic profile of AFB1 pointed to spring as the season with the highest aflatoxin level (0.086¿g/kg), followed by winter and summer (0.075 and 0.030¿g/kg, respectively), and to a lesser degree, autumn (0.017¿g/kg). Moreover, wet and dry TMR (Total Mixed Ration) feeding systems (i.e. AFB1: 0.076 and 0.068¿g/kg; Aflatoxin G1 (AFG1): 0.050 and 0.011¿g/kg, respectively) showed a greater content of the analyzed aflatoxins in comparison with compound feed (i.e. AFB1: 0.039¿g/kg; AFG1: 0.007¿g/kg). The fact that the majority of the samples collected were based on compound feed shows that this type was preferred by most dairy farmers. The undetectable levels of aflatoxins in the organic homemade compound feedstuff are also worth mentioning. While none of the feedstuff samples contained amounts over those permitted under European legislation (5¿g/kg), the theoretical extrapolation of the carryover rate suggested in previously published experiments of AFB1 to AFM1 in secreted cow's milk predicts that only one of the feed samples studied had a positive aflatoxin level (53.4ng/kg) higher than the legal limit for raw cow's milk.
Revista:
FOOD RESEARCH INTERNATIONAL
ISSN:
0963-9969
Año:
2014
Vol.:
57
Págs.:
152 - 161
The oxidative stability of seven oils with different fatty acid profiles was assessed. Oxidation at 0, 2 and 4 h at 180 °C was monitored by measuring the absorbance of thiobarbituric acid reactive substances (TBARS) along the absorption spectrum (300¿600 nm), the volatile aldehydes (HS-SPME¿GC¿MS) and the fatty acid profile (FID-GC).
TBARS absorption spectrum behavior depended on the lipid composition of heated oils. Higher absorbance increments during heating were noticed at 390 nm compared to 532 nm (from 2 to 21 fold higher depending on the oil), pointing to its better sensitivity to detect oxidation. Furthermore, a close relationship between ABS390, the loss of polyunsaturated fatty acids and their corresponding oxidation compounds (volatile aldehydes) was revealed by Principal Component Analysis.
Multiparametric equations allowed predicting the formation of volatile aldehydes of heated oils by measuring only two parameters: TBARS390 during their heating, and the lipid profile in unheated oils (MUFA, ¿-3 and ¿-6). Results pointed out the interest of choosing ABS390 when the oxidative evolution of vegetable oils under heating is assessed by the TBARS test
Revista:
CONSTRUCTION AND BUILDING MATERIALS
ISSN:
0950-0618
Año:
2014
Vol.:
73
Págs.:
1 - 12
Two polycarboxylate ether copolymers were assessed as superplasticizers (SPs) for hydrated lime pastes modified with two reactive compounds, nanosilica (NS) and ceramic metakaolin (MK). Characterization of the molecular structure of the SPs by Size Exclusion Chromatography, XRD, FTIR and MALDI-TOF (Matrix Assisted Laser Desorption Ionization Time-of-Flight) mass spectrometry was performed. The structures of the polymers were seen to be star- and worm-like shapes. A close relationship was found between the molecular architecture and the flowability of the pastes, being the star-shaped plasticizer the most efficient. Zeta potential assessment allowed us to elucidate a steric hindrance as the main action mechanism for these polymers. The large specific surface area of nanosilica led to a large SPs consumption as compared with metakaolin with lower surface area. However, SPs in MK¿lime samples were attached favourably on the C¿S¿H and aluminate hydrates, so that the dispersing action was greater with respect to NS¿lime suspensions.
Revista:
REVISTA INTERNACIONAL DE EDUCACIÓN Y APRENDIZAJE
ISSN:
2255-453X
Año:
2014
Vol.:
2
N°:
1
Págs.:
83 - 92
Los medios audiovisuales son herramientas adecuadas hoy en día para ilustrar el desarrollo de las clases magistrales impartidas por el profesor universitario. El alumno se desenvuelve con soltura en estos soportes, y la utilización de estos medios es un óptimo complemento para una buena comprensión del tema. Particularizando esta acción en estudios experimentales, como la Química, las ventajas que aporta el empleo de estos materiales son claras, tanto en el entendimiento de los temas como en el propio acercamiento del alumno a aspectos más prácticos y relacionados con el ejercicio profesional al que se dedicarán cuando finalicen los estudios. El presente trabajo evalúa los resultados de aplicar las nuevas tecnologías en la enseñanza de la Química a estudiantes de la Universidad de Navarra. Se pretende identificar elementos propios del ejercicio profesional del químico y relacionar los contenidos teórico-prácticos de las asignaturas con el mismo, consiguiendo además con ello un mejor conocimiento de la materia objeto de estudio.
La percepción de los alumnos ha sido ciertamente positiva en términos de un incremento de interés por las materias implicadas y de una mejora en la comprensión de las mismas.
Revista:
MEAT SCIENCE
ISSN:
0309-1740
Año:
2014
Vol.:
96
N°:
3
Págs.:
1185 - 1190
Reduced-energy and reduced-fat Bologna products enriched with ¿-3 polyunsaturated fatty acids were formulated by replacing the pork back-fat by an oil-in-water emulsion containing a mixture of linseed-algae oil stabilized with a lyophilized Melissa officinalis extract. Healthier composition and lipid profile was obtained: 85 kcal/100 g, 3.6% fat, 0.6 g ALA and 0.44 g DHA per 100 g of product and ¿-6/¿-3 ratio of 0.4. Technological and sensory problems were not detected in the new formulations. Reformulation did not cause oxidation problems during 32 days of storage under refrigeration. The results suggest it is possible to obtain reduced-fat Bologna-type sausages rich in ALA and DHA and stabilized with natural antioxidants, applying the appropriate technology without significant effects on the sensory quality, yielding interesting products from a nutritional point of view.
Revista:
CONSTRUCTION AND BUILDING MATERIALS
ISSN:
0950-0618
Año:
2014
Vol.:
58
Págs.:
147 - 158
The performance of air lime mortars modified by the incorporation of large amounts of nanostructured colloidal silica ¿ nanosilica, NS - (6, 10 and 20 wt.% with respect to lime) was the main objective of this work. Fresh mixture properties (water demand, setting time and plastic shrinkage), mechanical strengths up to one year and specimens¿ durability after accelerated ageing conditions (climatic chamber, freeze-thaw cycles and sulfate attack by MgSO4 corrosion test) were evaluated. NS was seen to have a strong pozzolanic activity in air lime media. Although the addition of NS gave rise to an increase in volume contraction, the superficial cracking caused by the drying shrinkage was reduced. A noticeable increase in the compressive strength values was observed in the NS-bearing mortars owing to the NS filler effect and the C-S-H formation, as proved by SEM examination and MIP analysis. A honeycomb-shaped network of C-S-H phases appeared as the prevailing microstructure in mortars with large NS additions. In the face of accelerated ageing processes, the presence of NS made the mortars more durable, delaying the progress of decay.
Autores:
Barbosa, K. B. F.; Pinheiro-Volp, A. C.; Marques-Rocha, J. L.; et al.
Revista:
NUTRITION
ISSN:
0899-9007
Año:
2014
Vol.:
30
N°:
11-12
Págs.:
1349 - 1354
OBJECTIVES:
The aim of this study was to investigate the associations between plasma total antioxidant capacity (TAC) and anthropometric, biochemical, clinical, and dietary measurements in young and apparently healthy individuals.
METHODS:
We evaluated 156 individuals (91 women and 65 men; ages 23.1 ± 3.5 y; body mass index 22 ± 2.9 kg/m(2)) for anthropometrics, biochemical markers, clinical, dietary, and some components of the antioxidant defense system, including the plasma TAC. Statistical analyses were performed to detect differences between individuals with TAC higher and lower than the mean value and to screen the associations between TAC and variables of interest. A linear regression model was fitted to identify TAC predictors.
RESULTS:
Daily caloric intake and macronutrient consumption were lower in individuals who exhibited the highest TAC values (P < 0.05). Linear regression analysis showed that daily calories and carbohydrate intake was a possible negative TAC predictor (P < 0.05). Nevertheless, there was no difference in the values of oxidized low-density lipoprotein in the individuals separated by means of TAC. In contrast, individuals whose plasma TAC values were above the mean showed higher low-density lipoprotein cholesterol concentrations, total cholesterol/high-density lipoprotein cholesterol values, and selenium in nails (P < 0.05).
CONCLUSIONS:
In physiological conditions, the caloric intake level seems to be an important factor to act in the modulation of plasma TAC, before establishing anthropometric impairments of body or metabolic composition, or both. Additionally, the plasma TAC increase may be able to act as a compensatory mechanism.
Autores:
Barbosa, K. B. F.; Pinheiro-Volp, A. C.; Marques-Rocha, J. L.; et al.
Revista:
REDOX REPORT (ONLINE)
ISSN:
1743-2928
Año:
2014
Vol.:
19
N°:
6
Págs.:
251 - 258
The aim of this study was to investigate the potential modulators of erythrocyte glutathione peroxidase (GPx) activity in young and apparently healthy individuals. One hundred one individuals (53 women and 48 men) were evaluated for anthropometric measurements, biochemical markers, clinical, dietary, and endogenous and exogenous components of the antioxidant defense system. Statistical analysis was performed to detect differences among subjects by the median of GPx activity. A linear regression model and Spearman correlation coefficients were used to screen the associations between GPx activity and interest variables. Individuals with higher GPx enzymatic activity were older and higher circulating levels of oxidized low-density lipoprotein (ox-LDL) values, but conversely lower nail concentrations of selenium and copper (P<0.05). The GPx activity was positively correlated to truncal fat percentage values (r=0.24, P=0.016), circulating levels of ox-LDL (r=0.28, P=0.004), and daily vitamin C intake (r=0.28, P=0.007), and negatively correlated to the nail concentration of selenium (r=-0.24, P=0.026). Interesting, it was noticed that the truncal fat percentage and circulating levels of ox-LDL explained 5.9 and 7.4% of the GPx enzymatic activity. Thus, preventive measures such as adequate antioxidant intake and proper fat percentage would be a priority in the nutritional care of young and apparently healthy individuals.
Revista:
MEAT SCIENCE
ISSN:
0309-1740
Año:
2014
Vol.:
98
N°:
4
Págs.:
615 - 621
The optimization of a gelled oil-in-water emulsion was performed for use as fat replacer in the formulation of ¿-3 PUFA-enriched cooked meat products. The linseed oil content, carrageenan concentration and surfactant¿oil ratio were properly combined in a surface response design for maximizing the hardness and minimizing the syneresis of the PUFA delivery system. The optimal formulation resulted in a gelled emulsion containing 40% of oil and 1.5% of carrageenan, keeping a surfactant¿oil ratio of 0.003. The gel was applied as a partial fat replacer in a Bologna-type sausage and compared to the use of an O/W emulsion also enriched in ¿-3. Both experimental sausages contributed with higher ¿-3 PUFA content than the control. No sensory differences were found among formulations. The selected optimized gelled oil-in-water emulsion was demonstrated to be a suitable lipophilic delivery system for ¿-3 PUFA compounds and applicable in food formulations as fat replacer.
Revista:
JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE
ISSN:
0022-5142
Año:
2014
Vol.:
94
N°:
4
Págs.:
744 - 751
BACKGROUND:
This applied research was done in order to obtain cooked products (bologna sausages) with significantly lower amounts of energy, total fat and saturated fat and higher amounts of ¿-3 fatty acids than conventional ones. Two subsequent experiments were performed.
RESULTS:
Experiment 1 aimed at pork back-fat reduction and enabled sausages to be obtained with 84¿g¿kg-1 fat and 1334¿kcal¿kg-1 , without significant negative effects on sensory quality. Carrageenan was used as fat replacer. Experiment 2 aimed at improving the lipid profile of the 'energy-reduced' sausages previously developed, by a partial substitution of the pork back-fat with a linseed oil-in water emulsion (substitution levels: 25-100%). Using the 100% substitution level gave rise to products with 27¿g¿kg-1 ¿-linolenic acid, and low saturated fat content (13.5¿g¿kg-1 ), showing good sensory results regarding taste, smell and texture. The use of antioxidant maintained low TBARs (thiobarbituric acid reactive substances) values in all formulations.
CONCLUSION:
It is possible to obtain cooked meat products (bologna sausages) with low energy, low saturated fat and a high amount of ¿-3 fatty acids simultaneously, applying a combination of the use of carrageenan, linseed oil emulsion and increment of water, without significant effects on sensory quality. Functional products, interesting from a nutritional standpoint, were achieved.
Revista:
EUROPEAN JOURNAL OF PHARMACEUTICAL SCIENCES
ISSN:
0928-0987
Año:
2014
Vol.:
62
Págs.:
309 - 316
Topical therapy is the ideal outpatient treatment of cutaneous leishmaniasis (CL) because of the ease of administration and lower cost. It could be suitable as monotherapy for localized cutaneous leishmaniasis (LCL) or in combination with systemic therapies for more severe forms of the disease. Although paromomycin (PM) ointment can be recommended for the treatment of LCL caused by Leishmaniamajor, a more effective topical treatment should be achieved regarding the physicochemical properties of this aminoglucoside and its rather poor intrinsic antileishmanial activity, that hampers the accumulation of enough amount of drug in the dermis (where the infected macrophages home) to exert its activity. In this work, we determined a 50% effective dose of 5.6 ¿M for a novel compound, bis-4-aminophenyldiselenide, against L. major intracellular amastigotes. This compound and PM were formulated in chitosan hydrogels and ex vivo permeation and retention studies in the different skin layers were performed with pig ear skin in Franz diffusion cells. The results showed that less than 2¿4% of the diselenide drug penetrated and permeated through the skin. In contrast, the percentage of PM penetration was about 25¿60% without important retention in the skin. When topically applied to lesions of L. major infected BALB/c mice, the novel diselenide chitosan formulation was unable to slow lesion progression and reduce parasite burden. Considerations during the process of novel drug development and
Revista:
JOURNAL OF ENVIRONMENTAL MANAGEMENT
ISSN:
0301-4797
Año:
2014
Vol.:
140
Págs.:
1 - 13
Polyphosphate-modified calcium aluminate cement matrices were prepared by using aqueous solutions polluted with toxic metals as mixing water to obtain waste-containing solid blocks with improved management and disposal. Synthetically contaminated waters containing either Pb or Cu or Zn were incorporated into phosphoaluminate cement mortars and the effects of the metal¿s presence on setting time and mechanical performance were assessed. Sorption and leaching tests were also executed and both retention and release patterns were investigated. For all three metals, high uptake capacities as well as percentages of retention larger than 99.9% were measured. Both Pb and Cu were seen to be largely compatible with this cementitious matrix, rendering the obtained blocks suitable for landfilling or for building purposes. However, Zn spoilt the compressive strength values because of its reaction with hydrogen phosphate anions, hindering the development of the binding matrix.
Revista:
CONSTRUCTION AND BUILDING MATERIALS
ISSN:
0950-0618
Año:
2013
Vol.:
48
Págs.:
218 - 228
The recycling of WFS in calcium aluminate cement mortars at high level of replacement (50%) was studied. Consistency and setting time were measured in fresh mortars. Two different curing conditions were used, the second one with the aim of enhancing the formation of stable cubic calcium aluminate hydrates. Compressive strength, pore size distribution and SEM examination were carried out to assess the effectiveness of CAC matrix in the recycling of WFS. The effect of the incorporation of a polymeric admixture - a chitosan derivative - was also explored. Leaching studies on hardened mortars of three target pollutants of the WFS (toxic metals Pb, Cr and Zn) were also done to evaluate their immobilization. By comparison with OPC mortars, the use of CAC showed several advantages, improving the compressive strength and the toxic metal retention.
Revista:
CEMENT AND CONCRETE RESEARCH
ISSN:
0008-8846
Año:
2013
Vol.:
43
N°:
1
Págs.:
12 - 24
The effect of individual and combined addition of both nanosilica (NS) and polycarboxylate-ether plasticizer (PCE) admixtures on aerial lime mortars was studied. The sole incorporation of NS increased the water demand, as proved by the mini-spread flow test. An interaction between NS and hydrated lime particles was observed in fresh mixtures by means of particle size distribution studies, zeta potential measurements and optical microscopy, giving rise to agglomerates. On the other hand, the addition of PCE to a lime mortar increased the flowability and accelerated the setting process. PCE was shown to act in lime media as a deflocculating agent, reducing the particle size of the agglomerates through a steric hindrance mechanism. Mechanical strengths were improved in the presence of either NS or PCE, the optimum being attained in the combined presence of both admixtures that involved relevant microstructural modifications, as proved by pore size distributions and SEM observations.
Revista:
MATERIALS CHARACTERIZATION
ISSN:
1044-5803
Año:
2013
Vol.:
80
Págs.:
36-49
The addition of a pozzolanic nanosized material, nanosilica (NS), onto lime binding materials was carried out with the aim of assessing the microstructural modifications attained by its presence that were related to the mechanical behavior. Simultaneously, a comparative study between five different drying methods for water removal was reported, and their influence on the pore structure evaluation is discussed. Solvent-exchange with isopropanol and freeze-drying methods were shown to remove the excess of free water efficiently, allowing us to measure the gel pores (< 10 nm) of the calcium silicate hydrated (C-S-H) phases and yielding the largest surface area values. By using vacuum drying, oven drying at 60ºC or oven drying at 105ºC macro-, meso- and micropores could not be properly measured. On the other hand, the addition of NS dramatically altered the mesopore range. As a result of the intercalation of NS particles between lime particles, a drop in the population of large and medium capillary pores (in the range of 20-100 nm) was observed, leading to reduced overall porosity. The NS was clearly proven to act as nanofiller. Finally, this filling effect of NS together with the development of C-S-H gel, as a consequence of the pozzolanictype reaction proved by the increase of population in the micropore range, notably enhanced the compressive strength of the lime binding materials, yielding values more than twice those of the NS-free materials.
Revista:
FOOD RESEARCH INTERNATIONAL
ISSN:
0963-9969
Año:
2013
Vol.:
51
N°:
1
Págs.:
132-140
The effect of storage temperature (65 degrees C, 48 h) on the oxidative stability of a food-grade water-in-oil-in-water (W/O/W) emulsion was studied by comparison with an oil-in-water (O/W) emulsion. The emulsions were prepared with linseed oil or olive oil, and in each case, two antioxidants were evaluated, an aqueous Melissa lyophilized extract and BHA. Emulsions were characterized using bright field light microscopy and the oxidation was monitored by measuring the lipid hydroperoxides, thiobarbituric acid reactive substances (TBARS), conjugated dienes (CD) and trienes (CT), alpha-tocopherol and Lipophilic Oxygen Radical Absorbance Capacity (L-ORACFL) Assay.
A great stability of olive oil emulsions was observed, without noticing differences between antioxidants or type of emulsion. This behavior was not observed in linseed oil emulsions. In this case the lipophilic antioxidant (BHA) seemed to be more efficient delaying the lipid oxidation in W/O/W emulsions than the water Melissa extract while the opposite occurs in the O/W emulsion. The type of antioxidant is a key factor in controlling oxidation in W/O/W and O/W emulsions which are prepared with highly polyunsaturated oils, but not in the case of highly monounsaturated ones.
Revista:
JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE
ISSN:
0022-5142
Año:
2013
Vol.:
93
N°:
4
Págs.:
876-881
BACKGROUND: A combined technological approach was applied in the development of healthier dry fermented sausages: a partial substitution of the pork back fat by pre-emulsified linseed oil and a partial replacement of sodium chloride with calcium ascorbate at two different levels, leading to low amounts of salt (14gSalt and 10gSalt, with 14 g and 10 g NaCl per kg of mixture, respectively). RESULTS: The developed products (14gSalt and 10gSalt) showed adequate results for aw (0.85 and 0.87) and pH (4.98 and 5.21), and low lipid oxidation values (1.4 x 104 and 1.5 x 105 g malondialdehyde (MDA) kg1). The lipid modification led to a significantly higher supply of -3 (23.3 g kg1) compared to the control (3.2 g kg1). Simultaneously, reductions of 38% and 50% in sodium content and a calcium supply of 4 and 5.2 g kg1 were achieved in the 14gSalt and 10gSalt formulations, respectively, compared to the control products (26 g salt and 0.87 g kg1 Ca). Instrumental analysis of colour and texture and sensory studies demonstrated that the organoleptic quality of the new formulations was similar to that of traditional products. CONCLUSIONS: The developed dry fermented sausages showed healthier properties than traditional ones owing to their reduced sodium and higher calcium content and a significant supply of -3 fatty acids. (c) 2012 Society of Chemical Industry
Revista:
JOURNAL OF HAZARDOUS MATERIALS
ISSN:
0304-3894
Año:
2013
Vol.:
260
Págs.:
89-103
The ability of calcium aluminate cement (CAC) to encapsulate toxic metals (Pb, Zn and Cu) was assessed under two curing conditions. Changes in the consistency and in the setting time were found upon the addition of the nitrates of the target metals. Both Pb and Cu caused a delay in CAC hydration, while Zn accelerated the stiffening of the mortar. Compressive strengths of the metal-doped mortars, when initially cured at 60ºC / 100%RH, were comparable with that of the free-metal mortar. Three different pore size distribution patterns were identified and related to the compounds identified by XRD and SEM. Sorbent capacities of CAC for the toxic metals were excellent: a total uptake was achieved for up to 3 wt.% loading of the three metals. In this way, CAC mortars were perfectly able to encapsulate the toxic metals, allowing the use of CAC for waste management as proved by the leaching tests.
Revista:
FOOD CONTROL
ISSN:
0956-7135
Año:
2013
Vol.:
30
N°:
2
Págs.:
423 - 432
Due to the fact that infants and children are especially sensitive to mercury and arsenic exposure, predominantly through diet, a strict control of the most widely consumed infant foods, especially infant cereals, is of paramount importance. Levels of both total mercury and arsenic in 91 different infant cereals from ten different manufacturers in Spain were determined by flow injection adapted to cold vapor and hydride generation atomic absorption spectrometry, respectively. Cereals were assessed in terms of the different types, the predominating cereal in the formulation, the added ingredients, and whether the cereal was organically or conventionally obtained. In general, the content of toxic elements (median (Q(1); Q(3))) found in infant cereals based on conventionally obtained raw materials (n = 74, Hg: 2.11 (0.42; 4.58), As: 21.0 (9.4; 50.9) mu g Kg(-1)) was lower than in cereals produced by organic methods (n = 17, Hg: 5.48 (4.54; 7.64), As: 96.3 (87.5; 152.3) mu g Kg(-1)). Mercury content in infant cereals shows the higher values in those formulations with ingredients susceptible to particulate contamination such as gluten-free or cacao-based cereals. The highest arsenic content appears in the rice-based cereals. The mercury and the inorganic arsenic dietary intakes for infants fed on the infant cereals studied were assessed, taking into account the different stages of growth. Organic infant cereals based on cocoa showed the highest risk intakes of mercury, very close to exceeding the intake reference. Just the opposite, 95% of the organically produced infant cereals and 70% of the conventional gluten-free infant cereals showed an inadmissible risk of arsenic intake. Thus, it seems prudent to call for continued efforts in standardizing routine quality control and in reducing arsenic levels in infant cereals; in addition it is essential that relevant legislation be established and regulated by EC regarding these two toxic elements.
Revista:
JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
ISSN:
0021-8561
Año:
2013
Vol.:
61
N°:
50
Págs.:
12260 - 122604
Tyrosol and caffeic acid are biophenols that contribute to the beneficial properties of virgin olive oil. The influence of hydroxypropyl-beta-cyclodextrin (HP beta-CD) on their respective antioxidant capacities was analyzed. The ORAC antioxidant activity of tyrosol (expressed as mu M Trolox equivalents/mu M Tyrosol) was 0.83 +/- 0.03 and it increased up to 1.20 +/- 0.11 in the presence of 0.8 mM HP beta-CD. However, the ORAC antioxidant activity of caffeic acid experienced no change. The different effect of HP beta-CD on each compound was discussed. In addition, the effect of increasing concentrations of different cyclodextrins in the development of ORAC-fluorescence (ORAC-FL) assays was studied. The ORAC signal was higher for HP beta-CD, followed by M beta-CD, beta-CD, gamma-CD and finally alpha-CD. These results could be explained by the formation of inclusion complexes with fluorescein.
Revista:
JOURNAL OF FOOD SCIENCE AND ENGINEERING
ISSN:
2159-5828
Año:
2012
Vol.:
2
N°:
1
Págs.:
56 - 63
A pre-emulsified mixture of linseed and algae oils (15/10) and stabilized with 686 ppm of a lyophilized water extract of
Melissa officinalis, was successfully applied in dry fermented sausages to increase the ¿-3 PUFA content. The objective of this work
was to evaluate the stability of this modified formulation during the storage and to compare it to that of a traditional formulation.
Traditional and modified products were stored during 90 days at 4 ºC in aerobic conditions. Fatty acid profiles, TBARS and volatile
compounds derived from oxidation were analyzed at 0, 30 and 90 days of storage. The fatty acid profiles did not significantly change
along the storage period. The stabilizing effect of the natural antioxidants of M. officinalis could contribute to detect no losses of ¿-3
PUFA in Modified (30 days: 2.13 g/100 g of product, 90 days: 2.33 g/100 g of product), whereas in Control products a slightly
significant reduction was detected (30 days: 0.34 g/100 g of product, 90 days: 0.29 g/100 g of product). After 90 days, the increases
of TBARS and hexanal content were much higher in Control than in Modified (Control: 1.41 mg MDA/kg & 17,915 ng dodecane/kg
of dry matter; Modified: 0.48 mg MDA/kg & 2,496 ng dodecane/kg of dry matter). In conclusion, the lyophilized water extract of M.
officinalis protected high ¿-3 PUFA of dry fermented sausages from oxidation along the storage time, guaranteeing the nutritional
improvements achieved with the modified formulation.
Revista:
EUROPEAN JOURNAL OF PHARMACEUTICS AND BIOPHARMACEUTICS
ISSN:
0939-6411
Año:
2012
Vol.:
81
N°:
2
Págs.:
273 - 280
In this work, the Film Method (FM), Reverse-Phase Evaporation (REV), and the Heating Method (HM) were applied to prepare PEG-coated liposomes of oxaliplatin with natural neutral and cationic lipids, respectively. The formulations developed with the three methods, showed similar physicochemical characteristics, except in the loading of oxaliplatin, which was statistically lower (P < 0.05) using the HM. The incorporation of a semi-synthetic lipid in the formulation developed by FM, provided liposomes with a particle size of 115 nm associated with the lowest polydispersity index and the highest drug loading, 35%, compared with the other two lipids, suggesting aft increase in the membrane stability. That stability was also evaluated according to the presence of cholesterol, the impact of the temperature, and the application of different cryoprotectants during the lyophilization. The results indicated long-term stability of the developed formulation, because after its intravenous in vivo administration to HT-29 tumor bearing mice was able to induce an inhibition of tumor growth statistically higher (P < 0.05) than the inhibition caused by the free drug. In conclusion, the FM was the simplest method in comparison with REV and HM to develop in vivo stable and efficient PEG-coated liposomes of oxaliplatin with a loading higher than those reported for REV. (C) 2012 Elsevier B.V. All rights reserved.
Revista:
CEMENT AND CONCRETE COMPOSITES
ISSN:
0958-9465
Año:
2012
Vol.:
34
N°:
8
Págs.:
964 - 973
The effect of two non-ionic chitosan derivatives (hydroxypropyl (HPCH) and hydroxyethyl (HECH) chitosans) and one ionic derivative (carboxymethylchitosan, CMCH) on the fresh-state properties of cement mortars was studied. Zeta potential measurements and particle size distribution were carried out in order to elucidate the action mechanism of the admixtures. Results were seen to be strongly dependent on substituents of the chitosan. Non-ionic derivatives had a weak dosage-related influence on the fresh-state properties. The ionic CMCH showed the more marked effect: it was found to act as a powerful thickener and to reduce the workable life of the fresh mixtures, whereas it caused a delay in the hydration of the cement particles. CMCH reduced the slump by 50% while commercial viscosity enhancers exhibiting larger molecular weights (hydroxypropylmethylcellulose, HPMC, and hydroxypropyl guaran, HPG) only reduced it by ca. 25%. The negative values of zeta-potential and the strong flocculating effect point to an adsorption of CMCH onto the positively charged cement particles. Optical microscopy and TEM observations showed the polymer giving rise to interlinking between cement particles.
Revista:
JOURNAL OF HAZARDOUS MATERIALS
ISSN:
0304-3894
Año:
2012
Vol.:
233-234
Págs.:
7 - 17
Cement mortars loaded with Cr, Pb and Zn were modified by polymeric admixtures [chitosans with low (LMWCH), medium (MMWCH) and high (HMWCH) molecular weight and hydroxypropylchitosan (HPCH)]. The influence of the simultaneous presence of the heavy metal and the polymeric additive on the fresh properties (consistency, water retention and setting time) and on the compressive strength of the mortars was assessed. Leaching patterns as well as properties of the cement mortars were related to the heavy metals-bearing solid phases. Chitosan admixtures lessened the effect of the addition of Cr and Pb on the setting time. In all instances, chitosans improved the compressive strength of the Zn-bearing mortars yielding values as high as 15 N mm¿2. A newly reported Zn phase, dietrichite (ZnAl2(SO4)4·22H2O) was identified under the presence of LMWCH: it was responsible for an improvement by 24% in Zn retention. Lead-bearing silicates, such as plumalsite (Pb4Al2(SiO3)7), were also identified by XRD confirming that Pb was mainly retained as a part of the silicate network after Ca ion exchange. Also, the presence of polymer induced the appearance and stabilization of some Pb(IV) species. Finally, diverse chromate species were identified and related to the larger leaching values of Cr(VI).
Revista:
FOOD CONTROL
ISSN:
0956-7135
Año:
2012
Vol.:
26
N°:
1
Págs.:
6 - 14
Lead and cadmium have become highly toxic metallic elements. There is an obvious toxicological impact of these elements on infants since their intestinal absorption is significantly higher than in adults, thus it is desirable to quantify lead and cadmium levels in commonly consumed infant foods. Zeeman background correction, transversely-heated graphite furnace atomic absorption spectrometry, was used to determine both the lead and cadmium content of 91 Spanish infant cereals. Cereals were assessed in terms of different types, cereal predominant in formulation and whether it was obtained organically or conventionally. Preliminary analysis revealed a noticeably higher content of lead and cadmium (median, Q1-Q3) in organic cereals (n = 17, Pb: 26.07; 21.36-51.63; Cd: 18.52; 16.56-28.50 mu g kg(-1)) in relation to conventional ones (n = 74, Pb: 10.78; 6.43-19.33; Cd: 7.12; 4.40-11.77 mu g kg(-1)). Three formulations exceeded European lead maximum levels. Added ingredients (milk, cocoa, fruit and honey) to the cereal base provide lead enrichment. For cadmium, this pattern was observed by cereal based on cocoa, but also the raw materials contributed with a dilution phenomenon, decreasing the final cadmium concentration in infant cereal. Apart from several organically produced cereals, lead content showed a narrow variation, where gluten-free cereals provide lower cadmium content than formulations containing gluten. Dietary intakes of both elements were assessed in comparison with the reference intake values proposed by the EFSA Panel on Contaminants in the Food Chain. Organic infant cereals based on honey and cocoa supplied the highest risk intakes of lead and cadmium, respectively. In accordance with the actual state of knowledge on lead and cadmium toxicity and attending to the upper limits calculated from risk intake values set by EFSA, it seems prudent to call for a revision of both heavy metals content regulated by EC to set a maximum guideline values for infant cereal at 55 and 45 mu g kg(-1), respectively.
Revista:
Plant foods for human nutrition
ISSN:
0921-9668
Año:
2011
Vol.:
66
N°:
4
Págs.:
328 - 334
Melissa officinalis L. (Lamiaceae) is consumed as a traditional herbal tea in the Mediterranean region. The cytotoxic effect of the 50% ethanolic and aqueous extract, determined by the MTT and NR assays, was evaluated in vitro on Human Colon Cancer Cell Line (HCT-116), using Triton 10% as positive control. The 50% ethanolic extract showed significant differences after 72 h of treatment, reducing cell proliferation to values close to 40%, even the lowest dose tested (5 mu g/ml). In the MTT assay, the same extract caused the lowest cell viability with 13% at a concentration of 1,000 mu g/ml after 72 h of treatment, being a value lower than Triton 10%. The antioxidant activity was also confirmed evaluating the capacity of the extracts to scavenge ABTS and DPPH radicals, and IC(50) values were highly correlated with the total phenolic and flavonoid content. Bioassay guided fractionation led to the isolation of an anti-proliferative compound, rosmarinic acid. Its structural elucidation was performed by HPLC/DAD/ESI/MS analysis. High dose of rosmarinic acid (1,000 mu g/ml) was clearly cytotoxic against HCT-116 cells, with a significant decrease in cell number since the earliest time point (24 h).
Revista:
LWT- Food Science and Tecnology
ISSN:
0023-6438
Año:
2011
Vol.:
44
N°:
4
Págs.:
875 - 882
Revista:
FERTILITY AND STERILITY
ISSN:
0015-0282
Año:
2011
Vol.:
96
N°:
5
Págs.:
1149 - 1153
Revista:
Meat Science
ISSN:
0309-1740
Año:
2011
Vol.:
88
N°:
4
Págs.:
705 - 711
Revista:
JOURNAL OF HAZARDOUS MATERIALS
ISSN:
0304-3894
Año:
2011
Vol.:
194
Págs.:
223 - 231
Autores:
Barbosa, KB; Volp, AC; Miranda, Helen Hermana; et al.
Revista:
LIPIDS IN HEALTH AND DISEASE
ISSN:
1476-511X
Año:
2011
Vol.:
10
N°:
1
Págs.:
61
Revista:
JOURNAL OF APPLIED POLYMER SCIENCE
ISSN:
0021-8995
Año:
2011
Vol.:
120
N°:
1
Págs.:
242 - 252
Revista:
FOOD ADDITIVES AND CONTAMINANTS PART B-SURVEILLANCE
ISSN:
1939-3210
Año:
2010
Vol.:
3
N°:
3
Págs.:
193 - 199
The incidence of aflatoxin M-1 (AFM(1)) in 69 different infant formulae marketed in Spain between 2007 and 2008 was studied and dietary intake estimated. Samples were analysed using an HPLC method coupled with fluorescence detection after immunoaffinity column clean-up. The toxin was detected in 26 formulae (37.7%) at levels below the permissible limit set by EC legislation, giving a range of 0.6-11.6 ng kg(-1) with a mean value of 3.1 ng kg(-1). Increasing occurrence was found in those formulae produced by the less complex manufacturing processes affecting casein/whey protein ratio: pre-term, 14.3%; starter, 35.3%; follow-up, 42.1%; toddler 87.6%; while hypoallergenic and lactose-free were totally exempt. Additionally, the influence of main protein source and physical state (powdered and ready-to-use formula) on AFM(1) occurrence was evaluated leading to similar conclusions. Dietary AFM1 weekly intake was observed to be stable around 1 ng kg(-1) bw for standard formula and 0.1 ng kg(-1) bw for pre-term feeding.
Revista:
FOOD ADDITIVES AND CONTAMINANTS PART B-SURVEILLANCE
ISSN:
1939-3210
Año:
2010
Vol.:
3
N°:
4
Págs.:
275 - 288
Aflatoxins (AFB1, AFB2, AFG1 and AFG2) are immunosuppressant, mutagenic, teratogenic and carcinogenic agents with a widespread presence in foodstuffs. Since human exposure to aflatoxins occurs primarily by contaminated food intake, and given the greater susceptibility of infants to their adverse effects, the quantification of these mycotoxins in infant food based on cereals is of relevance. Aflatoxin levels were determined in 91 Spanish infant cereals classified in terms of non- and organically produced and several types from 10 different manufacturers, using a extraction procedure followed by inmunoaffinity column clean-up step and HPLC with fluorescence detection (FLD) and post-column derivatisation (Kobra Cell system). Daily aflatoxin intake was also assessed. Preliminary analysis showed a valuable incidence of detected infant cereal samples at an upper concentration level than the detection limit for total aflatoxin (66%), corresponding to a 46, 40, 34 and 11% for AFB1, AFB2, AFG1 and AFG2, respectively. Lower aflatoxin values (median, Q1, Q3) in conventional infant cereal (n = 74, AFB1: LOD (n.d.; 0.02), AFB2: n.d. (n.d.; 0.01), AFG1: LOD (n.d.; 0.004), and AFG2: n.d. (n.d.; LOD) and total AF (AFtotal): 0.01 (LOD; 0.04 mu g kg-1) in comparison with infant cereal ecologically produced (n = 17, AFB1: 0.02 (0.02; 0.21), AFB2: n.d. (n.d.; 0.03), AFG1: 0.02 (0.01; 0.05), and AFG2: 0.007 (n.d.; 0.02) and AFtotal: 0.05 (0.03; 0.31 mu g kg-1) were found. In addition, five organic formulations (3.11, 1.98, 0.94, 0.47 and 0.21 mu g kg-1) exceeded European AFB1 legislation (0.10 mu g kg-1) versus two conventional cereals (0.35 and 0.12 mu g kg-1). According to the type of infant cereal, those with cocoa had the highest aflatoxin levels. Gluten-free and cereals with dehydrated fruits had an intermediate level and milk- or honey-based cereals and multi-cereals contained the lowest levels. With the exception of the non-compliant cocoa-based organic formulation, none of the infant cereals analyzed gave a higher intake of 1 ng kg-1 body weight per day, suggesting that infants fed on infant cereals are exposed to a low health hazard. Nevertheless, manufacturers are advised for continued efforts in routine monitoring and a more careful selection of raw material to minimize aflatoxin levels in these infant foods.
Revista:
Microchemical Journal
ISSN:
0026-265X
Año:
2010
Vol.:
96
N°:
2
Págs.:
415 - 421
Revista:
Meat Science
ISSN:
0309-1740
Año:
2010
Vol.:
85
N°:
2
Págs.:
373 - 377
Revista:
BIOLOGICAL TRACE ELEMENT RESEARCH
ISSN:
0163-4984
Año:
2010
Vol.:
133
N°:
3
Págs.:
304 - 312
Revista:
EUROPEAN JOURNAL OF PHARMACEUTICS AND BIOPHARMACEUTICS
ISSN:
0939-6411
Año:
2010
Vol.:
74
N°:
2
Págs.:
265 - 274
Biodegradable poly (lactic-co-glycolic) acid (PLGA) nanoparticles incorporating cisplatin have been developed to evaluate its in vivo efficacy in tumor-bearing mice.
In vitro Study proved two mechanisms of action for cisplatin depending on the dose and the rate at which this dose is delivered. In vivo study, 5 mg/kg of cisplatin nanoparticles administered to mice, exhibited a tumour inhibition similar to free cisplatin, although the area under cisplatin concentration-time Curve between 0 and 21 days (AUC(0-21)) had lower Value for the formulation than for drug solution (P < 0.05). This result was associated with a higher activation of apoptosis in tumor, mediated by caspase-3, after nanoparticles administration. Toxicity measured as the change in body weight, and blood urea nitrogen (BUN) plasma levels showed that cisplatin nanoparticles treatment did not induce significant changes in both parameters compared to control, while for free drug, a statistical (P < 0.01) increase was observed. In addition, a good correlation was found between time profiles of tumor volume and vascular endothelial growth factor (VEGF) plasma levels, suggesting that its expression could help to follow the efficacy of the treatment. Therefore, the PLGA nanoparticles seem to provide a promising carrier for cisplatin administration avoiding its side effects without a reduction of the efficacy, which was consistent with a higher activation of apoptosis than free drug.
Revista:
Meat Science
ISSN:
0309-1740
Año:
2010
Vol.:
85
N°:
2
Págs.:
274 - 279
Capítulos de libros
Libro:
Proceedings of the 6th Historic Mortars Conference - HMC 2022
Lugar de Edición:
Ljubljana
Editorial:
University of Ljubljana
Año:
2022
Págs.:
620 - 633
Microencapsulated Phase Change Materials (PCMs) were introduced in air lime rendering mortars in order to improve the thermal comfort of the inhabitants and the energy efficiency of buildings of the Architectural Heritage under the premises of minimum intervention and maximum compatibility. PCMs were directly added during the mixing process to fresh air lime mortars in three different percentages: 5, 10 and 20 wt. %. Some chemical additives were also incorporated to improve the final performance of the renders: a starch derivative as an adhesion booster, metakaolin as pozzolanic addition to shorten the setting time and to increase the final strength; and a polycarboxylate ether as a superplasticizer to adjust the fluidity of the fresh renders avoiding an excess of mixing water. The specific heat Cp, the enthalpy ¿H ascribed to the phase change and the melting temperature of the PCMs were determined by Differential Scanning Calorimetry (DSC). The capacity of the renders to store/release heat was demonstrated at a laboratory scale, proving by thermal conductivity measurements the effectiveness of PCMs for the reduction of gaps between peak and offpeak thermal loads as well as for the delay in the appearance of the peaks. The favourable results proved the effect of these PCMs with respect to the thermal performance of these rendering mortars, offering a promising way of enhancement of the thermal efficiency of building materials of the Cultural Heritage.
Libro:
Proceedings of the 6th Historic Mortars Conference - HMC 2022
Lugar de Edición:
Ljubljana
Editorial:
University of Ljubljana
Año:
2022
Págs.:
634 - 648
Different batches of repair lime rendering mortars were designed by mixing microencapsulated Phase Change Materials (PCMs) and other additives. The final aim of these renders is to improve the thermal efficiency of the envelope of the Built Heritage, while allowing the practitioners to apply a render with positive final performance. The combinations of the PCMs in different weight percentages, a superplasticiser (to increase the fluidity of the render keeping constant the mixing water), an adhesion improver and a pozzolanic additive were studied. The adhesion of these renders onto bricks and limestone specimens and the shrinkage and cracking of the mortars were studied in detail. X-ray diffraction technique was used to study the composition and evolution of the carbonation process. Compressive strength measurements were studied in hardened specimens. In addition, the porous structure of the rendering mortars was studied by mercury intrusion porosimetry to assess the effect of the PCMs¿ addition. Samples underwent accelerated climatic ageing to study their durability and the preservation of the thermal efficiency. Results have shown that these thermally enhanced mortars are feasible materials for real-life application in the context of architectural heritage restoration and conservation.
Libro:
Proceedings PRO 130 : 5th Historic Mortars Conference
Lugar de Edición:
Paris
Editorial:
RILEM Publications S.a.r.l.
Año:
2019
Págs.:
155 - 168
Active coatings to be applied onto hardened surfaces of lime rendering and masonry mortars and stones of the Built Heritage were developed. Nano-heterostructures of TiO2/ZnO (50:50 and 10:90) were obtained by Flame Spray Pyrolysis as photocatalytic agents with expanded sensitivity towards solar light, instead of the restricted UV dependence of the pure TiO2 or ZnO. A superhydrophobic medium was simultaneously prepared and photocatalytic nanoparticles were added to obtain the coatings. The active products were expected to prevent the water absorption of the substrates and the subsequent degradation effects as well as to allow the stones and mortars to act as self-cleaning materials, reducing the dirt deposition and the biological colonization. Dispersions were applied onto the surface of lime mortars and siliceous stone. Measurements of the photocatalytic oxidation activity of the coatings were carried out by means of the NO degradation, showing a very good efficiency of the nanoparticles even at long term tests (values of NO oxidation of ca. 35%). Water contact angle assessment evidenced a strong hydrophobization of the treated surfaces, with WCA values higher than 140º. The results proved the synergistic effect of these coatings with respect to the durability of the treated substrates, giving rise to a promising way of preventive conservation for building materials of the Cultural Heritage.
Libro:
Proceedings PRO 130 : 5th Historic Mortars Conference
Lugar de Edición:
Paris
Editorial:
RILEM Publications S.a.r.l.
Año:
2019
Págs.:
330 - 345
This work reports the obtaining of lime-based grouts as repairing materials. Microsilica was added as pozzolanic additive to enhance the compressive strength of the hardened grouts. Sodium oleate, as water repellent admixture, and different superplasticizers (SPs) were also incorporated to reduce the water absorption and to enhance the injectability of the grouts. Polycarboxylate ether (PCE), polynaphthalene sulfonate (PNS), melamine sulfonate (MMS) and polyacrylic acid (PA) were tested as SPs. Regarding the fluidity of the grouts, PCE was seen to improve the injectability, followed by PNS, MMS and PA. However, PCE addition was also accompanied by a severe delay in the setting time. The other three superplasticizers did not provoke significant delays in the hardening of the samples. The water contact angle underwent an increase pointing to an effective hydrophobization of the surface as a consequence of the water repellent admixture. The combination with PCE was the most effective in keeping the water repellency in comparison with the control sample (lime grout + oleate). MMS yielded high compressive strengths and durability of the mortars, in the face of freezing-thawing cycles, was enhanced.
Libro:
RILEM Proceedings PRO 130
Lugar de Edición:
Paris
Editorial:
RILEM Publications S.a.r.l.
Año:
2019
Págs.:
359 - 372
Different rendering mortars were prepared by mixing air lime and air lime-pozzolanic nanosilica with TiO2 and sodium oleate as, respectively, photocatalytic and water repellent agents, added in bulk. The aim of the work was to design and obtain new rendering mortars with improved durability focusing in the reduction of the water absorption of these materials and in their self-cleaning and biocide effect. To achieve a better distribution of the TiO2 particles, which was expected to enhance their efficiency, different dispersing agents were also incorporated to the fresh mixtures. Four diverse polycarboxylate ethers superplasticizers and a poly-naphthalene-sulfonate were tested. Workability and fluidity of the fresh rendering mortars were determined to guarantee the applicability of the final products. Water contact angle was monitored with the aim of assessing the hydrophobicity of the mortars lent by the water repeller. The biocide effect was studied by means of the culture of a strain of Pseudomonas fluorescens. The colonization of the mortars¿ surface was analyzed by determining the number of colonies forming units (CFU) after several days subjecting the samples to suitable T and RH conditions. At the same time, the surface of the mortars was irradiated with solar light to activate the photocatalyst. Results showed the efficiency of the sodium oleate in reducing the water uptake of the rendering mortars.
Libro:
Tradición, versatilidad e innovación en la cal: un material de excelencia
Lugar de Edición:
Pamplona
Editorial:
Grupo de Investigación MIMED. Servicio de Publicaciones de la Universidad de Navarra
Año:
2018
Págs.:
268 - 279
Diferentes morteros de cal fueron modificados por la incorporación en masa de aditivos fotocatalíticosnanoestructurados (TiO2 o TiO2 dopado con hierro (Fe-TiO2) o vanadio (V-TiO2)). Las propiedades plásticas y endurecidas de estos morteros han sido evaluadas para estudiar la influencia de estos nanoaditivos. Los retrasos en la demanda de agua observados en las pastas de cal se atribuyeron al impedimento de la difusión de CO2 dentro de la pasta. El TiO2 y el TiO2 dopado no mostraron reactividad puzolánica alguna.
El examen por microscopía electrónica de barrido de los morteros de cal mostró que las fases predominantes en la microestructura eran placas hexagonales de portlandita y las aglomeraciones gruesas escalenoédricas de calcita. Se encontró que el Fe-TiO2 se distribuía homogéneamente, mientras que el análisis EDS demostró la tendencia al aglomeramiento del V-TiO2. La capacidad de absorción de agua no se vio afectada por la incorporación de nanoaditivos, lo cual es una característica favorable para la aplicación de estos morteros.
Libro:
Tradición, versatilidad e innovación en la cal: un material de excelencia
Editorial:
Grupo de Investigación MIMED. Servicio de Publicaciones de la Universidad de Navarra
Año:
2018
Págs.:
228 - 240
El presente trabajo tiene como principal objetivo estudiar las interacciones que se producen cuando se adicionan separadamente dos superplastificantes (PNS ¿sulfonato de polinaftaleno- y LS ¿lignosulfonato-) a un conglomerante aéreo (cal aérea Cl 90-S) y a uno hidráulico formado por cal aérea a la que se le ha añadido metacaolín como material puzolánico, y los efectos que dichas adiciones tienen en las propiedades de los sistemas. Para la fabricación de los morteros, se empleó árido calcáreo. Adicionalmente, se efectuaron ensayos de durabilidad en morteros con la composición citada, sometiéndolos a ciclos de hielo-deshielo y a ataque con sulfatos.
Aunque se realizaron algunas medidas con las pastas en estado fresco, la mayoría de los experimentos (resistencia a compresión y a flexión, TG-ATD, DRX, FTIR-ATR, porosimetría de intrusión de mercurio) se realizaron tras períodos de fraguado del mortero de 7, 28, 91, 182 y 365 días.
Se detectaron fases silicatadas y silicoaluminatadas en los morteros estudiados, a pesar de que las experiencias se realizaron a temperatura ambiente y con un bajo porcentaje de material puzolánico (¿20 %). La presencia de LS impidió el proceso de carbonatación, lo que a su vez provocó un decrecimiento en los valores de resistencia mecánica cuando se trataba de morteros hidráulicos. Se observó asimismo una mayor porosidad y un mayor tamaño medio de poro en el caso de sistemas con LS. La durabilidad (ciclos hielo-deshielo) de los morteros mejoró notable
Libro:
Tradición, versatilidad e innovación en la cal: un material de excelencia
Lugar de Edición:
Pamplona
Editorial:
Grupo de Investigación MIMED. Servicio de Publicaciones de la Universidad de Navarra
Año:
2018
Págs.:
251 - 262
Los morteros de relleno o inyección, especialmente destinados a reparación de cavidades y defectos de albañilería, deben fluir adecuadamente en estado fresco y combinar resistencia y durabilidad. Para conseguir algunas de estas características pueden utilizarse aditivos químicos: superplastificantes, para mejorar la fluidez; adiciones puzolánicas, para conseguir resistencias adecuadas en ambientes con limitado acceso de CO2 y una mejora de la durabilidad; e hidrofugantes, de manera que, sin perjudicar la permeabilidad de estos materiales al vapor de agua, se evite la penetración de agua por capilaridad mejorando la durabilidad.
Sin embargo, en la mayor parte de los casos, toda la información disponible se circunscribe al efecto de un único aditivo, sin contemplar el posible efecto conjunto o incluso sinérgico de las combinaciones más interesantes de dos o más aditivos y/o adiciones puzolánicas. El estudio de las sinergias entre estos componentes ofrece posibilidades muy interesantes de avance científico-técnico. Precisamente este es el objetivo del trabajo: diseño de nuevos morteros de inyección de cal que puedan ser utilizados para la restauración del Patrimonio Edificado mediante combinación adecuada de aditivos superplastificantes (éteres de policarboxilato, condensados de naftaleno-formaldehído, sulfonato de melamina y ácido poliacrílico), hidrofugante (oleato sódico) y adiciones minerales puzolánicas (microsílice y metacaolín).
Libro:
Productos cárnicos seguros, nutritivos y saludables. Red de excelencia Consolider PROCARSE
Editorial:
Red Consolider PROCARSE
Año:
2017
Págs.:
13 - 19
ISBN:
978-84-9-697-6357-5
Libro:
Proceedings of the 4th Historic Mortars Conference HMC 2016
Lugar de Edición:
Thessaloniki
Editorial:
Aristotle University of Thessaloniki
Año:
2016
Págs.:
383 - 390
A new range of repair lime mortars were obtained by using as superplasticizer a polynaphthalene sulfonate-based polymer (PNS) and metakaolin as pozzolanic addition. Adsorption isotherms showed that PNS exhibited a high affinity for air lime particles with 52.08 mg¿g-1 as maximum sorption capacity in pure air lime media. Mathematical treatment of experimental data showed an optimal adjustment to a Freundlich model, in which interactions arising from multilayer adsorption are taken into account. The experimental results suggested a great interaction of PNS with air lime media (pure air lime or air lime with MK). Zeta potential curves of air lime systems titrated with PNS showed a larger zeta potential reduction, giving rise to a charge reversal, as a consequence of the high anionic charge density of this polymer (2.44 meq of anionic charge¿g-1). A flat adsorption was proposed as the attachment model of this admixture, owing to its higher anionic charge density and to its linear shape. The electrostatic repulsion was then the main action mechanism to explain the PNS function. In the hardened state, the combination of PNS and MK resulted sometimes in moderate mechanical strength increases and in a clear enhancement of the durability in the face of freezing-thawing cycles.
Libro:
Proceedings of the 4th Historic Mortars Conference HMC 2016
Lugar de Edición:
Thessaloniki
Editorial:
Aristotle University of Thessaloniki
Año:
2016
Págs.:
721 - 728
This contribution dealt with the design of different air lime mortars and pastes by combining a nanostructured pozzolanic additive, nanosilica, and different dispersing agents, superplasticizers (two different polycarboxylate ethers (PCE), a polynaphthalene sulfonate-based polymer (PNS) and a lignosulfonate (LS)). In pure air lime systems, the highest effectiveness was shown by the PCE1, whereas the PNS was the less effective superplasticizer. In samples with nanosilica, the PCE1 was also the most effective superplasticizer. LS was seen to be effective at low dosages. In the presence of the pozzolanic additive, there was a high consumption of polycarboxylates. Nanosilica provided no ¿active¿ adsorption sites, resulting in a slight decrease of the zeta potential values. PCE1 showed low adsorbed amounts, better dispersing action and required lower dosage of plasticizing agent. There was a positive combination between lime mortars with nanosilica and polycarboxylates, which resulted in a mechanical strength improvement. Also the combined presence of nanosilica, for example, with PNS or with LS yielded better compressive strengths, being LS more effective than PNS: SEM images showed the better formation of C-S-H phases in LS-mortars.
Libro:
Proceedings of the 4th Historic Mortars Conference HMC2016
Lugar de Edición:
Thessaloniki
Editorial:
Aristotle University of Thessaloniki
Año:
2016
Págs.:
688 - 695
The obtaining of self-cleaning mortars is very interesting to apply them in Built Heritage. Atmospheric pollutants, mainly carbonaceous particles and gases like NOx and SO2 can lead to severe aesthetic and functional damages in artworks. In the case of mortars and renders, the use of photocatalysts -usually based on TiO2- can be worthy of consideration. Photocatalysts, after being activated by light, are able to oxidize pollutants avoiding their deposition onto building materials. In this work, different air lime mortars modified upon the addition of TiO2-based photocatalysts were obtained and studied. Photocatalysts can be incorporated in bulk and the changes in fresh state properties were studied as well as the effect of the presence of the photocatalysts on the pore structure and mechanical resistance. Finally, the photocatalytic efficiency of these materials was carried out by means of a NOx abatement test. Results showed that the presence of the photocatalysts had a positive impact on the preservation of the lime mortars characteristics.
Libro:
Proceedings of the 4th Historic Mortars Conference HMC 2016
Lugar de Edición:
Thessaloniki
Editorial:
Aristotle University of Thessaloniki
Año:
2016
Págs.:
375 - 382
A superplasticizing admixture of natural origin, lignosulfonate (LS), was incorporated to air lime mortars sometimes modified with a pozzolanic additive, metakaolin, to obtain a new range of repair mortars to be applied in Built Heritage. LS improved the flowability of the air lime samples and showed good slump retention over time: for example, after 150 minutes of the air lime pastes preparation, blends with LS lost only ca. 13% of the slump value. Experimental results showed that LS interfered with the carbonation due to its ability to form Ca2+ complexes. Adsorption isotherms and zeta potential measurements showed that LS was scarcely adsorbed onto lime and C-S-H particles. Due to its branchy structure, LS exhibited an adsorption mechanism leading to steric hindrance as the main responsible mechanism for avoiding flocculation. The presence of free LS molecules in the dispersion was seen to improve the plasticizing effect of this polymer. Flexural and compressive strengths as well as the durability in the face of freezing-thawing cycles of these mortars were also determined to assess the applicability of these repair mortars.
Libro:
Proceedings of the 14th International Congress on the Chemistry of Cement (CD): Section 6, Alternative binders
Lugar de Edición:
Beijing
Editorial:
The Chinese Ceramic Society; China Building Materials Academy
Año:
2015
Págs.:
1 - 11
The rationale is that polyphosphate-CAC matrices have shown interesting potential to solidify/stabilize heavy metals, owing to the aforementioned acid-base reaction that yields a compact and low porous matrix mainly composed of ACP - amorphous calcium phosphate -, which can be able to retain hazardous compounds. We aimed to take advantage of the reactivity of one of the sludge components: the sludges with relatively large concentrations of phosphate are expected to act themselves as reactants that, interacting with the CAC, could result in a very effective retaining system of the sludge constituents. Sludge samples from two locations have been incorporated in high proportion within the mix. We discussed the effects of the sludge on the CAC mortar and a possible interaction mechanism is provided.
Libro:
Proceedings of the 14th International Congress on the Chemistry of Cement (CD): Section 4: Admixtures
Lugar de Edición:
Beijing
Editorial:
The Chinese Ceramic Society; China Building Materials Academy
Año:
2015
Págs.:
1 - 14
Although CAC is used in many building as well as industrial structures, its modification upon addition of photocatalytic additives has not yet been addressed and that is precisely the purpose of the present work. We intend to obtain for the first time depolluting CAC mortars modified with different amounts of TiO2. The effect of the TiO2 incorporation on setting time, compressive strength and mineralogical composition of the CAC mortars will be assessed. PCO efficiency of these TiO2-bearing CAC mortars will be also measured by means of the NOx abatement. The modified depolluting mortars could be then applied in different tunnels, industrial floors and urban areas in which CACs are usually applied.
Libro:
Proceedings of the 14th International Congress on the Chemistry of Cement (CD): Section 4, Admixtures
Lugar de Edición:
Beijing
Editorial:
The Chinese Ceramic Society; China Building Materials Academy
Año:
2015
Págs.:
1 - 8
The behaviour of different superplasticizers admixtures was assessed for hydrated lime pastes and mortars. Sometimes, air lime pastes and mortars were modified with two supplementary cementing materials (SCMs), namely nanosilica (NS) and metakaolin (MK). Two different polycarboxylate ethers, a lignosulfonate and a naphthalene condensed sulfonate superplasticizer were added to lime pastes and mortars and their effects on fresh-state properties as well as on the mechanical strengths were evaluated. A close relationship was found between the molecular architecture of the plasticizers and the flowability of the pastes. Zeta potential assessment allowed us to elucidate the main action mechanisms for these admixtures. In the case of polycarboxylate ethers, the large specific surface area of nanosilica led to a large SPs consumption as compared with metakaolin with lower surface area. However, polycarboxylate ethers in MK-lime samples were attached favourably to the C-S-H and aluminate hydrates, so that the dispersing action was greater with respect to NS-lime suspensions.
Libro:
Proceedings of the 3rd Historic Mortars Conference HMC 13
Lugar de Edición:
Glasgow, Scotland
Editorial:
University of the West of Scotland
Año:
2013
Págs.:
1 - 8
This work deals with the effect of the nanosilica addition on the performance of aerial lime mortars. Several lime mortars were prepared and modified upon the addition of 3, 6, 10 and 20 wt.% of nanosilica. The presence of nanosilica increased the water demand of the fresh mixtures and reduced the appearance of superficial cracks after the spreading of the mortars onto a porous stone. Setting time underwent a delay when the amount of nanosilica ranged from 3 to 10 wt.%. However, samples with 20 wt.% of nanosilica showed a shortened setting time compared to plain lime mortars. Nanosilica reacted with Ca(OH)2 particles, yielding C-S-H compounds and, acting as a nanofiller, nanosilica also caused a pore blockage in the mesoporous range. These facts resulted in an increase in both compressive strength and durability after undergoing freezing-thawing processes. Overall, the addition of nanosilica clearly improves several characteristics of the aerial lime mortars in order to prepare enhanced mixtures to be used for restoration works.
Libro:
Productos cárnicos para el S XXI: seguros, nutritivos y saludables
Lugar de Edición:
Cáceres
Editorial:
Servicio de Publicaciones Universidad de Extremadura
Año:
2011
Págs.:
113 - 120
