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In this work, low-Pt content nanocatalysts (≈ 5 wt. %) supported on Hollow Carbon Spheres (HCS) were synthesized by two routes: i) colloidal conventional polyol, and ii) surfactant-free Bromide Anion Exchange (BAE). The nanocatalysts were labelled as Pt/HCS-P and Pt/HCS-B for polyol and BAE, respectively. The physicochemical characterization of the nanocatalysts showed that by following both methods, a good control of chemical composition was achieved, obtaining in addition well dispersed nanoparticles of less than 3 nm TEM average particle size (d) on the HCS. Pt/HCS-B contained more Pt0 species than Pt/HCS-P, an effect of the synthesis method. In addition, the structure of the HCS remains more ordered after BAE synthesis, compared to polyol. Regarding the catalytic activity for the Oxygen Reduction Reaction (ORR) in 0.5 M KOH, Pt/HCS-P and Pt/HCS-B showed a similar performance in terms of current density (j) at 0.9 V vs. RHE than the benchmark commercial 20 wt. % Pt/C. However, Pt/HCS-P and Pt/HCS-B demonstrated a 6 and 5-fold increase in mass catalytic activity compared to Pt/C, respectively. A positive effect of the high specific surface area of the HCS and its interactions with metal nanoparticles and electrolyte, which promoted the mass transfer, increased the performance of Pt/HCS-P and Pt/HCS-B. The high catalytic activity showed by Pt/HCS-B and Pt/HCS-P for the ORR, even with a low-Pt content, make them promising cathode nanocatalysts for Anion Exchange Membrane Fuel Cells (AEMFC).

This work reports the synthesis and characterization of metal-free electrocatalysts made from Brosimum alicastrum waste as the carbon source. The residues were washed and grounded to a fine powder. The thermogravimetric analysis carried out on the raw sample showed that the optimal synthesis temperature is 700 °C. Thus, the raw sample was pyrolyzed at 700 °C and activated with potassium hydroxide (KOH) in a 2:1 ratio (KOH/fine power) to improve its properties. Afterwards, hydrazine was used as the nitrogen source for doping. The physicochemical characteristics of pyrolyzed, activated, and doped carbons were studied and their electrochemical properties were determined using cyclic and linear voltammetry techniques. The electrochemical measurements indicate that the sample doped at 140 °C has an acceptable onset potential (0.854 V vs. RHE), while the one doped at 160 °C shows the highest current density among the synthesized electrocatalysts (2.61 mA cm-2). Although the catalyst performance is lower compared to commercial 20% Pt/C, this biomass precursor favors the oxygen reduction reaction in alkaline media.

In the search of insight concerning the interaction of molecules of different complexity with the desulfurization and hydrogenation sites, a series of NiMo sulfided catalysts with active particles of different morphology were tested in the hydrodesulfurization of dibenzothiophene, 4,6-dimethyldibenzothiophene, and in the hydrogenation of naphthalene and cyclohexene. The size and stacking of the NiMoS nanoparticles were modified both by increasing the Mo loading and by decreasing the metal-support interaction. The results show that not all the hydrogenation reactions take place at the same type of site, and that the hydrogenating sites at the top basal plane have greater hydrogenating power than those at the edge. The direct desulfurization of dibenzothiophene and 4,6-dimethyldibenzothiophene takes place at coordinatively unsaturated sites (CUS), whereas for the hydrogenation-desulfurization reaction route, the site where the rate controlling step takes place is influenced by the structure and reactivity of the reacting molecule. For dibenzothiophene, the rate controlling step takes place at hydrogenating sites at the top basal plane while for 4,6-dimethyldibenzothiophene it takes place at CUS. Therefore, to efficiently eliminate sulfur from molecules like 4,6-dimethyldibenzothiophene, as required in ultra-low sulfur fuels, the catalyst must have good hydrogenating capacity but more importantly, a high number of CUS.

Biodegradable films based on agar with glycerol (GLY) as a plasticizer were developed by incorporating hydroalcoholic garlic extract (HGE) on the film surface. The effect of GLY content (0, 15, or 30 wt%) and different concentrations of HGE (0, 0.5, 1, or 1.5 μg/mL) on the physicochemical and transport properties of the films was evaluated. The optical (color and transparency), mechanical (tensile test), transport (diffusion and water vapor transmission rate), thermal (thermogravimetric analysis) structural (infrared spectroscopy and X-ray diffraction), and morphological (scanning electron microscope) properties were analyzed. The impregnation of HGE increased the transparency values and decreased the luminosity, tensile strength, elastic modulus, and crystallinity of the agar films. The formulation of 30 wt% GLY with 1.5 μg/mL HGE, identified as 30 GLY [1.5], showed a similar thermal stability that of a neat agar film. The agar films with 30 wt% GLY showed the lowest diffusion coefficient and water vapor transmission rate, indicating that volatile compounds are slowly released. From the results the formulation 30 GLY [1.5] could be used as a film to transport and to release HGE which is supported by a biodegradable matrix and this system has a potential use as insect semiochemical for plague control.

The ethanol dehydration and subsequent ethylene oligomerization to short-chain olefins using catalysts based on ZSM-5 zeolite was studied in detail. P, Fe, and Ni were added by incipient wetness impregnation on zeolites with two SiO2/Al2O3 molar ratios (50 and 80). The catalysts were characterized by N2 adsorption–desorption, XRD, SEM–EDX, FTIR spectroscopy of adsorbed pyridine, and XPS techniques, while the catalytic activity was evaluated using an isothermal fixed-bed reactor. The impregnation of P, Fe, and Ni significantly improved the formation of the desired C3+ olefins (olefins having three or more C atoms). Particularly, the zeolite with SiO2/Al2O3 molar ratio = 50 and impregnated with P, exhibited the highest selectivity (C3+ olefins > 45 wt% at TOS = 5 h) in comparison with the rest of the evaluated catalysts. On the contrary, catalysts with SiO2/Al2O3 molar ratio = 80 showed lower selectivity to C3+ olefins, producing more side products (i.e. paraffins, aromatics and diethyl-ether).

In this work, high surface area N-doped carbon synthesis from Sargassum spp. is reported as a low cost alternative for electrocatalysts production for the oxygen reduction reaction (ORR). First, Sargassum spp. was activated with potassium hydroxide (SKPH) and then doped with hydrazine (SKPHD). As a result of the activation process, SKPH obtained a high surface area (2289 m2 g−1), 0.16% nitrogen and 2.63% sulfur content; it also showed four-electron-transfer mechanism when tested as electrocatalyst in alkaline medium. Besides, SKPHD presented 3.60% nitrogen content in the bulk and higher ORR activity (0.838 V onset potential vs. RHE and 4.59 mA cm−2 current density) very close to 20% Pt/C (5.25 mA cm−2). Results indicate that using seaweeds as a synthesis precursor is an alternative for the Sargassum spp. disposal in the Caribbean due to its high availability and efficiency towards ORR.

The respiration chamber method is considered to be the most precise approach for measuring enteric methane emissions in cattle. A set of experimental runs was carried out in which increasing volumes of pure methane (168.5, 194.9, 234.9, 264.9, 301.0, 339.8, and 375.7 L per run) were gravimetrically released into open-circuit respiration chambers to simulate the volumes of methane eructated by cattle of different weights. The aim was to assess the effect of the volume of methane released into the chambers on percentage of methane recovered at the exit by the infrared methane analyzer. It was found that as the volume of methane released into the respiration chambers was decreased, methane recovery percentages were concomitantly reduced. The recovery percentages ranged from 103.7% down to 18.3% and from 102.7% down to 31.6% for chambers one and two, respectively. It can be concluded that the slow stabilization of methane inside the large volume chamber, when injected at low rates from the cylinder, led to low recoveries of the gas at an air extraction rate of 300 L/min. As a result, the recovery of methane was constrained, leading to underestimation of the actual volumes released from the pure methane cylinders. Poor mixing of air inside the chambers did also constrain the recovery of methane with the experimental approach employed. The possible implications for methane measurements in respiration chambers under in vivo conditions with cattle are discussed.

This study presents the synthesis and physicochemical characterization of functionalized carbon-based materials prepared from cassava residues (Manihot esculenta). Cassava residues were obtained from a local market, washed, dried and ground to small particle size. This powder was mixed with different aqueous media: diluted sulfuric acid (0.2 M), nejayote and deionized water. These mixtures were treated in an autoclave at 200 °C for 4 h. The physicochemical characteristics of samples were studied by SEM, TGA, FTIR, XPS and elemental analysis. The chemical composition of C:O was similar among groups, but TGA suggested that the hydrochar prepared with sulphuric acid presented a better thermal stability, with a decomposition peak at 435 °C, which was 80 °C higher than samples prepared with deionized water. The acid sample also had lower mass loss (47.3%). The SEM images showed that sulphuric acid promoted the formation of small needle-like structures, while samples prepared using nejayote and water showed agglomerates with a few spherical shapes. The proximate analysis indicated that there was a carbon enrichment from 41% from the original sample to 62% after the hydrothermal process.

In this work, a pH-responsive drug-carrier based on chitosan-silica nanospheres was developed as a carrier for Albendazole (ABZ), a poorly water-soluble anthelmintic drug. Spherical silica nanoparticles were obtained by Stöber method and further etched to obtain mesoporous particles with sizes ranging from 350 to 400 nm. The specific BET area of nanoparticles increased from 15 m2/g to 150 m2/g for etched silica, which also exhibited a uniform pore size distribution. X-ray powder diffraction showed the presence of amorphous phase of silica and a low-intensity peak attributed to ABZ for the drug-loaded nanoparticles. A uniform layer of chitosan was obtained ranging from 10 to 15 nm in thickness due to the small concentration of chitosan used (0.45 mg of chitosan/mg of SiO2). The in vitro evaluation of hybrid nanoparticles was performed using four cervical cancer cell lines CaSki, HeLa, SiHa and C33A, showing a significant reduction in cell proliferation (&gt, 85%) after 72 h. Therefore, we confirmed the encapsulation and bioavailability of the drug, which was released in a controlled way, and the presence of chitosan delayed the release, which could be of interest for the development of prolonged release drug delivery systems.

Ruminants are the main source of methane emissions from the agricultural sector. Emission inventories and mitigation strategies require reliable technics of measurement. The respiration chamber methodology is a precise approach for measuring enteric methane emissions in cattle. A set of experiments was carried out to validate two respiration chambers for measuring enteric methane emissions of cattle. The chambers were calibrated considering three main components: the methane analyzer, the air duct and air extraction system, and the chamber itself, by evaluating linearity and response time of the analyzer, plateau variability and high purity methane recoveries in chambers. Recovery test calculations carried out after releasing high purity methane into the chambers gave calibration factors of 0.95 ± 0.05 and 1.03 ± 0.03 for the complete system of respirations chambers one and two, respectively, with corresponding uncertainties of 4.87 and 2.49%. Thus, the respiration chambers for enteric methane measurements of cattle at the University of Yucatan, Mexico function with precision and accuracy. This technique can be used to establish methane inventories and methane mitigation strategies in cattle.

The objective of this study was to determine methane (CH4) yield by crossbred cattle fed tropical grasses. A total of 66 individual determinations of dry matter intake (DMI) and 42 determinations of organic matter intake (OMI) in relation to the production of enteric CH4 were carried out. Methane measurements in heifers were performed in open-circuit respiration chambers. Heifers (Bos indicus × B. taurus) with an average live weight of 288.5 ± 55.7 kg fed tropical grasses as basal ration were used. An average intake of 8.22 and 7.80 kg of DM and OM per day were recorded. An average enteric CH4 production of 88.0 g/heifer/day was determined. It was found that DMI and OMI in relation to CH4 production have a coefficient of determination (R2) of 0.73 and 0.70 respectively, to predict CH4 emissions. It is concluded that the methane yield (18.07 g CH4/kg DM intake) predicted by regressing DM intake against methane production represents a reliable value to be used for the estimation of enteric CH4 inventories for cattle grazing in the tropical regions of Mexico.

The establishment of microorganisms and particularly fungi on rock surfaces, which is favored by humid tropical climates, may accelerate the degradation of historical monuments and buildings and thereby cause the irreversible loss of rich cultural heritage. Therefore, it is urgent to search for new ways to preserve such buildings. The in vitro antifungal activity of calcium zinc hydroxide dihydrate [CaZn2(OH)6·2H2O] (CZ) synthesized via the sol–gel method has been previously reported for limestone. The present study reports for the first time, the minimum fungicidal concentration (MFC) of CZ obtained via mechanochemical processing, against diverse fungi involved in biodeterioration processes of limestone and dolostone. We found that CZ nanoparticles had a fungicidal effect on all evaluated fungi, at concentrations of 156–1250 μg/mL. The MFC depends on the number of cells in conidia and the presence of melanin in cell walls. For these reasons, Pestalotiopsis maculans and Curvularia lunata, which had more than four cells and melanin pigmentation, both required a greater CZ concentration (1250 μg/mL) for inhibition, compared with species from the genera Penicillium oxalicum and Aspergillus niger, which had one cell and were strongly inhibited. Thus, CZ nanoparticles are promising candidates for application in treatments to restore the cultural heritage.

Metal-free electrocatalysts for the oxygen reduction reaction (ORR) were synthesized from cassava residues through a thermal functionalization with sulfuric acid. Their electrocatalytic activities were tested through the ORR performance in basic media. Chemical composition in samples seems to play an important role in their electroactivity, more than textural properties, as the sulfur-treated high-temperature sample (Sy800) has the best performance with an onset potential of 0.69 V vs RHE (reversible hydrogen electrode) and a current of −2.32 mA cm−2 at 0.3 V vs RHE. These functionalized cassava residues are promising materials to be used like carbon-based metal-free electrocatalysts.

In this research, sorghum procyanidins (PCs) and procyanidin B1 (PB1) were encapsulated in gelatin (Gel) to form nanoparticles as a strategy to maintain their stability and bioactivity and for possible applications as inhibitors of metalloproteinases (MMPs) of the gelatinase type. Encapsulation was carried out by adding either PCs or PB1 to an aqueous solution of A- or B-type Gel (GelA or GelB) at different concentrations and pH. Under this procedure, the nanoparticles PCs–GelA, PCs–GelB, PB1–GelA, and PB1–GelB were synthesized and subsequently characterized by experimental and computational methods. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) revealed that all types of nanoparticles had sizes in the range of 22–138 nm and tended to adopt an approximately spherical morphology with a smooth surface, and they were immersed in a Gel matrix. Spectral analysis indicated that the nanoparticles were synthesized by establishing hydrogen bonds and hydrophobic interactions between Gel and the PCs or PB1. Study of simulated gastrointestinal digestion suggested that PCs were not released from the Gel nanoparticles, and they maintained their morphology (SEM analysis) and antioxidant activity determined by Trolox-equivalent antioxidant capacity (TEAC) assay. Computational characterization carried out through molecular docking studies of PB1 with Gel or (pro-)metalloproteinase-2 [(pro-)MMP-2], as a model representative of the PCs, showed very favorable binding energies (around −5.0 kcal/mol) provided by hydrogen bonds, van der Waals interactions, and desolvation. Additionally, it was found that PB1 could act as a selective inhibitor of (pro-)MMP-2.

Ruminant animals contribute significantly to methane emissions in tropical regions. Nonetheless, there are few facilities available in those regions of the world for in vivo measurement of methane production in cattle. T he aim of the present work was to describe the design, construction and operation of respiration chambers for in vivo measurement of methane production in cattle in Mexico. Locally available materials were used in the construction. Walls, roof and doors were constructed of thermic panels with two windows of acrylic at the front so the animal can be observed at all times. Chambers have an air volume of 9.97 m 3 . Air is drawn from the chamber at a rate of 500 L/min by the effect of mass action flow generators. Methane was measured in air samples with an infrared analyzer. Chambers operate under a slight negative pressure of around -500 Pa. Air temperature inside the chambers is kept at 23 °C with an air conditioner, while relative humidity is maintained at 55 % with a dehumidifier. Functioning of the chambers was evaluated in Bos indicus , Nelore cattle fed Taiwan grass ( Pennisetum purpureum ) and a concentrate (18 % crude protein), and measurements were made during runs of 23 h duration. Methane production was on average 173.2 L per day, while the emission factor was 17.48 L methane per kilogram o dry matter consumed. It concludes that this respiration facility is capable of measuring methane production accurately in cattle fed tropical rations.

The process of biodeterioration is one of the main problems affecting historical monuments and buildings. On rock surfaces, different types of microorganisms establish in the most adequate niches and accelerate degradation, leading to the irreversible loss of cultural heritage. Therefore, new ways to preserve cultural heritage must be urgently studied to prevent such damage. In this study, the broad-spectrum antimicrobial activity of calcium zinc hydroxide dehydrate [Ca(Zn(OH)3)2·2H2O] (CZ) and zinc oxide (ZnO) nanoparticles synthesized by the sol–gel method is examined against fungal and bacterial model organisms. The selected microbes were inhibited by both nanoparticles, yet CZ was the most effective, with a bactericidal activity of 1.25 to 5 mg/mL and a fungicidal activity of 0.625 mg/mL. Both nanoparticles caused structural damage to the evaluated fungal cells, resulting in morphological changes and affecting the germination of conidia. For the first time in the literature, the antibacterial activity and the mode of action of CZ are reported. In conclusion, CZ nanoparticles are shown to be potential candidates for the treatment of rock surfaces of built cultural heritage., We are grateful for the financial support of the National Council for Science and Technology (Consejo Nacional de Ciencia y Tecnología [CONACyT]) of the “Fronteras de la Ciencia 138” project. Additional thanks are extended to CONACyT for the doctoral scholarship granted to MSC 282192.

The evaluation of the antifungal activity of Mg(OH)2 and Ca(OH)2 nanoparticles (NPs), synthesized by sol–gel method and their mixtures at different concentrations, is reported. The antifungal activity of the hydroxide NPs was studied using Aspergillus niger and Penicillium oxalicum isolated from stone surfaces. These model organisms were selected due to their ability to grow on outdoor and indoor climates and their significant impact on human health. Moreover, the antifungal activity of Mg(OH)2 and Ca(OH)2 NPs dispersed in positively charged polymeric matrices based on partially quaternized poly(2-(dimethylamino ethyl) methacrylate) (pDMAEMA) was studied. With respect to the morphology, particle size, and textural properties of the NPs, the mixtures of Mg–Ca hydroxides revealed a uniform and smaller particle size, along with a greater surface area, as compared to pristine Ca(OH)2 NPs. However, the Ca(OH)2 and a mixture of Mg(OH)2 and Ca(OH)2 (10:90 weight ratio) NPs, showed an enhanced growth inhibition of A. niger and P. oxalicum, suggesting that the effect of particle size on the antifungal activity would not be a preponderating factor. In addition, improved antifungal properties against A. niger and P. oxalicum were detected in composite coatings based on hydroxide NPs dispersed in quaternized p(DMAEMA-co-METAI). The use of these systems might provide promising composite materials with potential antifungal properties for various applications., This study was financially supported by the National Council for Science and Technology (Consejo Nacional de Ciencia y Tecnología [CONACYT, Mexico]) of the “Fronteras de la Ciencia No. 138” project and by the Community of Madrid under the “Climortec”, BIA2014−53911-R, “Geomaterials 2” Programme (S2013/MIT_2914), and Multimat Challenge (S2013/MIT-2862). A.S.-F. would like to gratefully acknowledge the financial support of Santander Universidades through “Becas Iberoamérica Jóvenes Profesores e Investigadores, España 2015” scholarship program. C.G.-S., R.Y.-M., and U.S.S. thank CONACYT and the Deutscher Akademischer Austauschdienst (DAAD, Germany) for financial support within the framework of the funding program for international mobility PROALMEX 2015 (CONACyT project: 267752 and DAAD project: 57271725). C.G.-S. and U.S.S. also thank the Deutsche Forschungsgemeinschaft (DFG, Germany) for financial support for this research under the scheme of the grant SFB-1278 “PolyTarget” project B02.

Resumen Introducción: el almidón resistente (AR) no se digiere completamente en el intestino humano sino que se fermenta en colon; disminuye el pH intestinal, ya que se producen ácidos grasos de cadena corta, interviniendo de manera benéfica en el tratamiento preventivo y curativo del cáncer de colon rectal. La pirodextrinización y la hidrólisis enzimática son modificaciones al almidón nativo (AN) que pueden incrementar la cantidad de AR. Objetivo: el objetivo de este proyecto fue evaluar los efectos del almidón nativo de M. cavendishAAA y de los almidones modificados química y enzimáticamente sobre diversos marcadores tumorales en ratas. Métodos: se realizaron modificaciones (química y enzimática) del AN del banano M. cavendishAAA y se evaluaron en ratas tratadas con 1,2-DMH. Se utilizaron 25 ratas Sprague Dawley machos divididas en cinco grupos experimentales: CP, CN, AN, PI y MER. Durante 4 semanas recibieron la dieta experimental asignada a cada grupo. Los grupos CP, AN, PI y MER recibieron 2 inyecciones s.c. (subcutáneas) semanales de 1,2-DMH (40 mg/kg) (semanas 3 y 4). En las heces se evaluaron el pH, la enzima β-glucuronidasa y los ácidos grasos de cadena corta, y se realizó un estudio histopatológico del ciego y el colon para detectar lesiones microscópicas. Resultados: la actividad de β-glucuronidasa disminuyó (p < 0,05) para los grupos AN, PI y MER en comparación con el CP. La mayor proporción de ácido butírico se observó en el AN (p < 0,05) frente al CN. El 60 % de las enteritis fueron de grado severo en el CP, mientras que en los grupos experimentales fueron de 40 %. Conclusiones: los gránulos de almidón nativo resistieron la pirodextrinización pero el tratamiento con α-amilasa rompió la estructura del gránulo de pirodextrina. De acuerdo a los tratamientos suministrados a las ratas, conforme mayor es la cantidad de AR presente en la dieta (AN), las células neoplásicas no avanzan más allá de la membrana basal, sugiriendo un posible efecto protector o anticancerígeno celular. Abstract Introduction: resistant starch (RS) is not completely digested in the human intestine but is fermented in the colon; intestinal pH decreases as short-chain fatty acids are produced. This is beneficial for health, and for preventing and treating rectal colon cancer. Pyrodextrinization and enzymatic hydrolysis are modifications to native starch (NS) that may increase the amount of RS. Objective: the objective of this project was to evaluate the effects of M. cavendishAAA native and both chemically and enzymatically modified starches on tumor markers in rats. Methods: modifications (chemical and enzymatic) were made to M. cavendishAAA NS, and were evaluated in rats with 1,2-DMH. Male Sprague Dawley rats (25) were used, divided into five experimental groups: PC, NC, NS, PI, and ERM. During 4 weeks they received the experimental diet assigned to each group. The PC, NS, PI and ERM groups received 2 weekly s.c. (subcutaneous) injections of 1,2-DMH (40 mg/kg) (third and fourth week). In feces, pH, β-glucuronidase enzyme, and short-chain fatty acids were evaluated, and a histopathological study was performed of the intestine to detect microscopic lesions. Results: the activity of β-glucuronidase decreased (p < 0.05) for NS, PI and ERM vs. PC. The highest proportion of butyric acid was observed in the NS (p < 0.05) vs. NC group. Sixty percent of enteritides were severe in grade in the PC group, and 40 % in the experimental groups. Conclusions: native starch granules resisted pyrodextrinization, but treatment with α-amylase broke the structure of the pyrodextrin granule. According to the treatments given to the rats, as the amount of RS present in the diet increases (NS), the neoplastic cells do not advance beyond the basement membrane, suggesting a possible cell-protective or anticancer effect.

Biocomposites of polylactic acid, thermoplastic starch, chitosan powder, and chitosan lyophilized powder were prepared using an extrusion process. The color, thermal, structural, mechanical, morphology, and antimicrobial properties were evaluated. The addition of thermoplastic starch and chitosan (chitosan powder and chitosan lyophilized powder) produced significant changes in color and heterogeneous surface morphology of the polylactic acid biocomposites. The thermal, mechanical, and morphometric properties of the material showed changes with the addition of thermoplastic starch and chitosan (chitosan powder and chitosan lyophilized powder). The biocomposites formulated with chitosan powder and chitosan lyophilized powder showed antifungal activity when evaluating this property. The biocomposites produced could be used in packaging applications.

Mesoporous silica nanoparticles (MSNs) are frequently functionalized to be used for specific applications, including catalysis and biomedical engineering. In this research, MCM-41-MSNs were synthesized by the sol–gel method and were functionalized with different quantities of (3-aminopropyl) triethoxysilane (APTES) using a post-grafting method to determine the physicochemical and structural changes in the MSNs. The functionalized materials were assessed by different characterization techniques, namely, TGA, FTIR, BET, SEM, TEM, DLS, zeta potential, SAXS, XRD and XPS. The FTIR data confirmed the presence of amino groups on the MSN surfaces, and the results from the XPS, TGA and zeta potential demonstrated that the APTES concentration during post-grafting directly affects the quantity of amino groups bound to the MSNs. The SAXS, TEM and nitrogen adsorption–desorption analyses showed that as the amount of APTES in the MSNs increases, the mesoporous structure become more disordered.

The antifungal and photocatalytic activity of mixed compounds of double hydroxide (CaZn2(OH)6•2H2O) with portlandite (Ca(OH)2) synthesized via sol-gel were evaluated. The compound was tested by in vitro assay to determine its antifungal activity using the agar diffusion and broth microdilution assays, applied to the fungal models: Aspergillus niger and Penicillium oxalicum. Also, these compounds were characterized by X-ray diffraction, infrared spectroscopy, dispersion light scattering, and its morphological structure was identified by HR-SEM and TEM-SAED which shows agglomerated particles formed by nanoparticle sizes between 100-500 nm, which are correlated whit hydrodynamic radio around 155 nm. Additionally, in the relation of microbiological assays, the outstanding minimum inhibitory concentration of unmixed calcium zincate hydroxide dihydrate (CZ) correspond to 156 μg/mL, however, when is mixed with 10% of Ca(OH)2 diminishes up to 78 μg/mL, indistinctively of the evaluated fungus. Likewise, a photocatalytic degradation test was carried out with methylene blue dye as a model organic pollutant, reaching an efficiency of ∼92%. Our results suggest that low concentrations of Ca(OH)2 improve the antifungal activity of CZ, without altering the solution stability, the photocatalytic and chemical properties of the compounds. Therefore, the compatibility with the limestone of both materials can be proposed as an excellent product to avoid fungal biodeterioration.

The present work focuses on the use of solid and agricultural residues from Aloe vera crops, as a source of antimicrobial agents and textile dyes. The roots from an A. vera plantation post-harvest were extracted with ethyl acetate, purified and phytochemically characterized to obtain five metabolites: aloesaponarin-I (1), deoxyerythrolaccin (2), lacaic acid D methyl ester (3), aloesaponarin-II (4), and aloesaponol-I (5). Acid hydrolysis of the solid industrial residue gave aloe-emodin (6) as the main product with a good yield. All of the components were tested for the first time against phytopathogenic bacteria strains, and deoxyerythrolaccin and lacaic acid D methyl ester were active against Xanthomonas campestris with MIC values of 46.86 and 93.75 μg/mL, respectively. Aloesaponarin-I and aloe-emodin, the main products, were tested as dyes for polyester fabrics using different mordants and pH bath conditions. The colour of each material was investigated in terms of the CIELAB L*, a* and b* values, and the colour fastness to light and washing was investigated according to the Mexican standard methods (NMX-A-074-INNTEX-2005; NMX-A-105-B02-INNTEX-2010). Aloesaponarin-I dyed polyester bright yellow but the final colour was very sensitive to the pH of the dye bath. Aloe-emodin dyed polyester deep yellow, and the fabrics showed good colour fastness to light and to domestic laundering. This study provides evidence that the phenolic components obtained from agricultural residues of the aloe industry can be useful organic alternatives as antimicrobial agents and textile dyes.

Hybrid bionanocomposites based on cellulose matrix, with silica nanoparticles as reinforcers, were prepared by one-pot synthesis of cellulose surface modified by solvent exchange method to keep the biopolymer net void for hosting inorganic nanoparticles. Neither expensive inorganic-particle precursors nor crosslinker agents or catalysts were used for effective dispersion of reinforcer concentration up to 50 wt %. Scanning electron microscopy of the nanocomposites shows homogeneous dispersion of reinforcers in the surface modified cellulose matrix. The FTIR spectra demonstrated the cellulose features even at 50 weight percent content of silica nanoparticles. Such a high content of silica provides high thermal stability to composites, as seen by TGA-DSC. The fungi decay resistance to Trametes versicolor was measured by standard test showing good resistance even with no addition of antifungal agents. This one-pot synthesis of biobased hybrid materials represents an excellent way for industrial production of high performance materials, with a high content of inorganic nanoparticles, for a wide variety of applications.

The effect of the phase composition of alumina supported NiMo catalytic precursors on thiophene hydrodesulfurization (HDS) was investigated. The catalytic precursors were prepared by impregnation of the commercial γ-Al2O3 with solutions of Anderson-type ammonium salts or co-precipitation of ammonium heptamolybdate and nickel nitrate. The precursors were characterized by XRD, BET specific surface area, pore volume and pore size, XPS, elemental analysis, TGA and 27Al MAS NMR. The chemical analyses by ICP showed for the NiMo-AP compounds a clear agreement between experimental and theoretical values according to stoichiometric values (Mo/Ni = 6), while for NiMo-COP deviations were observed (Mo/Ni ∼ 7). The specific surface area and pore volume of NiMo-AP/γ-Al2O3 precursors were greater than those of the NiMo-COP/γ-Al2O3 precursors, 387/325 m2 g−1 vs. 283/265 m2 g−1, and 0.34/0.27 cm3 g−1 vs. 0.21/0.15 cm3 g−1, respectively; whereas the average pore radius for all systems was 12 A. XRD and XPS analysis confirmed the presence of (NH4)4[NiMo6O24H6]·5H2O and Mo5+/Mo6+ for solids obtained by Anderson-type precursors, whereas NiMo-COP/γ-Al2O3 precursors exhibited Mo6+ from NiMoO4 and MoO3. The NiMo precursor obtained from conventional methods showed a higher amount of sulfur than those synthesized from the Anderson-type phase (6.9 to 4.9 wt%), although this does not mean a highly active sample or optimum sulfided active phase. 27Al solid-state MAS NMR showed higher tetrahedrally coordinated aluminium for the NiMo-COP/γ-Al2O3 catalytic precursors. The catalytic activity was strongly influenced by the type of catalytic precursor and metallic wt%. The activity of the catalysts obtained by the sulfided Anderson-type ammonium salts was greater than the sulfided solids obtained by the conventional method, suggesting that these precursors result in a better active phase with a molar ratio (Ni + Mo)/S = 1.01 (likely “Ni–Mo–S” species), due to lower loss of the Ni promoter into the alumina support (27Al NMR) and the lowest metal–support interaction (TGA). The catalysts obtained the HDS products, butane and cis-butene independent of the precursor type. Furthermore, the catalysts with 15 wt% Mo were more efficient than those obtained with 8 wt% Mo.

More recently, the biological colonization of stone heritage and consequently its biodeterioration has become the focus of numerous studies. Among all microorganisms, fungi are considered to be one of the most important colonizers and biodegraders on stone materials. This is why the development of new antifungal materials requires immediate action. ZnMgO nanoparticles (NPs) have several exciting applications in different areas, highlighting as an efficient antimicrobial agent for medical application. In this research, the application of Zn-doped MgO (Mg1–xZnxO, x = 0.096) NPs obtained by sol–gel method as antifungal coatings on dolomitic and calcitic stones has been explored as a means to develop effective protective coatings for stone heritage. Moreover, the photocatalytic and antifungal activity of Mg1–xZnxO NPs were comparatively studied with single ZnO and MgO NPs. Thus, compared to the MgO and ZnO nanomaterials, the Mg1–xZnxO NPs exhibited an enhanced photocatalytic activity. After UV irradiation for 60 min, 87% methylene blue was degraded over Zn-doped MgO NPs, whereas only 58% and 38% of MB was degraded over ZnO and MgO NPs, respectively. These nanoparticles also displayed a better antifungal activity than that of single pure MgO or ZnO NPs, inhibiting the growth of fungi Aspergillus niger, Penicillium oxalicum, Paraconiothyrium sp., and Pestalotiopsis maculans, which are especially active in the bioweathering of stone. The improved photocatalytic and antifungal properties detected in the Mg1–xZnxO NPs was attributed to the formation of crystal defects by the incorporation of Zn into MgO. The application of the MgO- and Zn-doped MgO NPs as protective coatings on calcareous stones showed important antifungal properties, inhibiting successfully the epilithic and endolithic colonization of A. niger and P. oxalicum in both lithotypes, and indicating a greater antifungal effectiveness on Zn-doped MgO NPs. The use of Zn-doped MgO NPs may thus represent a highly efficient antifungal protection for calcareous stone heritage., This research has been financially supported under projects FOMIX-Yuc 2008–108160, CONACYT LAB-2009-01-123913, 188345, Fronteras de la Ciencia No. 138, by the Community of Madrid under the Geomaterials 2 Programme (S2013/MIT_2914), Climortec, BIA2014–53911-R and MAT2013-47460-C5-5-P, and the Autonomous Region Program of Madrid, MULTIMAT CHALLENGE (S2013/MIT-2862). A.S.-F. would like to gratefully acknowledge the financial support of Santander Universidades through “Becas Iberoamérica Jóvenes Profesores e Investigadores, España 2015” scholarship program.

The antifungal properties of protective coatings based on Ca[Zn(OH)3]2·2H2O have been evaluated both on glass slides and on three different limestone materials, which have regional significance as the most commonly used building and restoration materials in the region, including for historic Mayan monuments and artifacts. The protective coatings were found to have excellent antifungal properties, inhibiting the growth of Penicillium oxalicum and Aspergillus niger, both in the dark and under illumination. Experiments were carried out at a laboratory test site under simulated photoperiod conditions, consisting of 24-h cycles of 12 h in the dark and 12 h under illumination: 21 days after inoculation and exposure to photoperiod conditions, no fungal growth was observed for any type of limestone, for both fungi. X-ray diffraction illustrated that the formation of calcium oxalate in the weddellite structure is an indicator of the fungal activity. Close inspection of samples with scanning electron microscopy (SEM) revealed that for all limestone substrates without protective coating, fungal growth was observed as well as fungal penetration into the limestone material. SEM images also show that the Ca[Zn(OH)3]2·2H2O coating is well-adhered to all substrates, without the presence of significant cracks in the coating. For the three limestone substrates with the protective coating, no fungal growth was observed, illustrating the excellent antifungal properties of the calcium zinc hydroxide dihydrate material.

This work reports the synthesis of N-doped porous carbon (NPC) with a high surface area from Sargassum spp. as a low-cost alternative for electrocatalyst production for the oxygen reduction reaction (ORR). Sargassum spp. was activated with potassium hydroxide at different temperatures (700, 750, and 800 °C) and then doped with pyridine (N700, N750, and N800). As a result of the activation process, the 800 °C sample showed a high surface area (2765 m2 g−1) and good onset potential (0.870 V) and current density (4.87 mA cm−2). The ORR performance of the electrocatalysts in terms of their current density was N800 > N750 > N700 > 750 > 800 > 700, while the onset potential decreased in the following order: N800 > 800 > 750 > 700 > N700 > N750. The fuel cell performance of the membrane electrode assembly (MEA) prepared with electrocatalyst synthesized at 750 °C and doped with pyridine was 12.72 mW cm−2, which was close to that from Pt/C MEA on both the anode and cathode (14.42 mW cm−2). These results indicate that NPCs are an alternative to the problem of Sargassum spp. accumulation in the Caribbean due to their high efficiency as electrocatalysts for ORR.

Background Appropriate training for community pharmacists may improve the quality of medication use. Few studies have reported the impact of such programs on medication management for patients with chronic kidney disease (CKD). Study Design Multicenter, cluster-randomized, controlled trial. Setting & Participants Patients with CKD stage 3a, 3b, or 4 from 6 CKD clinics (Quebec, Canada) and their community pharmacies. Intervention Each cluster (a pharmacy and its patients) was randomly assigned to either ProFiL, a training-and-communication network program, or the control group. ProFiL pharmacists completed a 90-minute interactive web-based training program on use of medications in CKD and received a clinical guide, patients' clinical summaries, and facilitated access to the CKD clinic. Outcomes Drug-related problems (primary outcome), pharmacists' knowledge and clinical skills, and patients' clinical attributes (eg, blood pressure and glycated hemoglobin concentration). Measurements Drug-related problems were evaluated the year before and after the recruitment of patients using a validated set of significant drug-related problems, the Pharmacotherapy Assessment in Chronic Renal Disease (PAIR) criteria. Pharmacists' questionnaires were completed at baseline and after 1 year. Clinical attributes were documented at baseline and after 1 year using available information in medical charts. Results 207 community pharmacies, 494 pharmacists, and 442 patients with CKD participated. After 1 year, the mean number of drug-related problems per patient decreased from 2.16 to 1.60 and from 1.70 to 1.62 in the ProFiL and control groups, respectively. The difference in reduction of drug-related problems per patient between the ProFiL and control groups was −0.32 (95% CI, −0.63 to −0.01). Improvements in knowledge (difference, 4.5%; 95% CI, 1.6%-7.4%) and clinical competencies (difference, 7.4%; 95% CI, 3.5%-11.3%) were observed among ProFiL pharmacists. No significant differences in clinical attributes were observed across the groups. Limitations High proportion of missing data on knowledge and clinical skills questionnaire (34.6%) and clinical attributes (11.1%). Conclusions Providing community pharmacists with essential clinical data, appropriate training, and support from hospital pharmacists with expertise in nephrology increases pharmacists' knowledge and reduces drug-related problems in patients with CKD who are followed up in clinics incorporating a multidisciplinary health care team.

Limestone is a sedimentary rock composed of calcium carbonate with minor amounts of silica, iron oxide, clay, dolomite, and organic material. These types of stones have been used extensively as building materials. Due to this, determination of their thermal properties is of the utmost importance. These properties depend on the microstructure and composition of each type of rock. In this study, the effect of the thermal treatment of three different limestone rocks from the Peninsula of Yucatan were studied, in the range from 100 °C up to 600 °C, using photothermal radiometry. These studies were complemented by the characterization of the crystalline phases using X-ray diffraction and effective porosity measurements performed by the saturation technique. It is shown that the thermal diffusivity, thermal conductivity, and specific heat of the limestone decrease as the temperature increases. This behavior can be related to increases in microcracks and effective porosity due to thermal treatments.

The time evolution of the bleaching effect, of hydrogen peroxide and two different concentrations of carbamide peroxide, on partially deteriorated human dental remains was analyzed by optical diffuse reflectance in the visible region of the spectrum. The optical measurements show that, after applying the first bleaching treatment, the reflectance increases. However for successive applications, a decrease of the reflectance is observed. This effect can be attributed to enamel teeth surface etching induced by the bleaching agents, allowing the inner dentin to contribute to the optical spectra and diminishing the reflectance. Additionally, in order to compare with previous studies in dentistry, colorimetric analysis of the process was also performed. The relevance in the use of protocols for cleaning valuable dental pieces in forensics, anthropology, and archeology is discussed.

Black corals (Antipatharians) are colonial cnidarians whose branched tree-like skeleton is constituted of chitin fibrils inside a lipoproteic matrix. The arrangement of the constituents of these materials provides a structure with outstanding physical properties. In this study, the structural properties of black coral skeletons of Antipathes caribbeana and Antipathes pennacea species are explored by means of thermal treatments in the range from room temperature up to 400 °C and the subsequent analysis using X-ray diffraction (XRD), infrared spectroscopy (FTIR), and thermal analysis (DSC/TGA). The effects of thermal treatment from room temperature up to around 210 °C induce the enhancement of the bands in the FTIR spectra and X-ray diffractograms, above that temperature, the FTIR and X-ray peaks become strongly attenuated. These effects are specially observed in the infrared bands associated to chitin at 3298 cm−1 and to the secondary amide stretching around 1663 cm−1, in particular, allowing the identification of the α-chitin in the black coral. XRD shows that the crystallinity index of the black coral chitin at room temperature is 24% and grows when the temperature increases, reaching a maximum value of 37% at 210 °C and decreases for higher temperatures. In addition, DSC and TGA measurements allowed identifying the most important transformation stages during the thermal treatments, namely, evaporation of water and the beginning and progress of degradation, depolymerization, and denaturation processes and finally, the degradation of the main functional groups of coral skeleton and coral chitin, in which the polysaccharide structure of chitin is depolymerized and the protein matrix is denatured.

Biodegradable segmented polyurethanes (BSPUs) were prepared with poly(caprolactone) as a soft segment, 4,4'-methylene bis (cyclohexyl isocyanate) and either butanediol (BSPU1) or dithioerythritol (BSPU2) as a chain extender. BSPU samples were characterized in terms of their physicochemical properties and their hemocompatibility. Polymers were then degraded in acidic (HCl 2N), alkaline (NaOH 5M) and oxidative (H(2)O(2) 30wt.%) media and characterized by their mass loss, Fourier transform infrared (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), X-ray diffraction (XRD) and scanning electron microscopy (SEM). Undegraded BSPU1 and BSPU2 exhibited different properties, such as the glass transition temperature T(g) of the soft segment (-25 vs. 4 degrees C), mechanical properties (600% vs. 900% strain to break) and blood coagulating properties (clotting time=11.46 vs. 8.13min). After acidic and alkaline degradation, the disappearance of the 1728cm(-1) band of polycaprolactone (PCL) on both types of BSPU was detected by FTIR. However, the oxidative environment did not affect the soft segment severely as the presence of PCL crystalline domains were observed both by DSC (melting temperature T(m)=52.8 degrees C) and XRD (2theta=21.3 degrees and 23.7 degrees ). By TGA three decomposition temperatures were recorded for both BSPU samples, but the higher decomposition temperature was enhanced after acidic and alkaline degradation. The formation of the porous structure on BSPU1 was observed by SEM, while a granular surface was observed on BSPU2 after alkaline degradation.

Silica gel and MCM-41 synthesized mesoporous materials were treated with either oxygen (O2), hexamethyldisiloxane (HMDSO) and organic vapors like ethanol (EtOH), and acrylonitrile (AN) inductive plasma. The radiofrequency power for the modification was fixed to 120 W and 30 min, assuring a high degree of organic ionization energy in the plasma. The surface properties were studied by infrared spectroscopy (FTIR), scanning electron microscopy, x-ray photoelectron spectroscopy and dynamic light scattering technique was used for characterizing size distributions. When the silica and MCM-41 particles were modified by AN and HMDSO plasma gases, the surface morphology of the particles was changed, presenting another color, size or shape. In contrast, the treatments of oxygen and EtOH did not affect the surface morphology of both particles, but increased the oxygen content at the surface bigger than the AN and HMDSO plasma treatments. In this study, we investigated the influence of different plasma treatments on changes in morphology and the chemical composition of the modified particles which render them a possible new adsorbent for utilization in sorptive extraction techniques for polar compounds.

In this work, the kinetics of diffusion of methylene blue in agar aqueous solution is studied using a photoacoustic technique. Two agar phantoms solutions in water with a relation of mass/volume of 0.01% and 0.05% were analyzed. The study was performed using a modified Rosencwaig photoacoustic cell that is enclosed by transparent windows, on both sides. The sample is deposited directly on top of the upper window. A red light beam, at a fixed modulation frequency, is sent through the lower window illuminating the sample and inducing the photoacoustic effect inside the closed chamber of the cell. At the beginning of the experiment, a droplet of 100μL of agar solution is deposited; afterwards, the signal stabilizes, and 10μL of methylene blue aqueous solution (0.0125 g · mL−1) is added to the surface of the agar. During the first seconds of the experiment, the photoacoustic signal amplitude increases followed by a gradual and long decay. Results for modulation frequencies in the range from 10Hz to 80Hz for both agar concentrations are presented. A simple theoretical approach is presented to analyze the experimental data. It is demonstrated that the kinetics of the process can be parameterized as a function of the changes of an effective optical absorption coefficient. From these results, the characteristic time, in which the dye diffusion process stabilizes, is obtained. It is found that this time is larger for samples with a higher agar concentration. These differences provide important results for biomedical sciences in which agar gels are used as phantoms resembling some of the properties of living organs and tissues.

Different fields such as archaeology, biomedicine, forensic science, and pathology involve the analysis of burned bones. In this work, the effects of successive thermal treatments on pig long bones, measured by photothermal radiometry and diffuse reflectance are reported. Measurements were complemented by X-ray diffraction and infrared spectroscopy. Samples were thermally treated for 1 h within the range of 25 °C to 350 °C. The thermal diffusivity and reflectance increase in the low-temperature range, reaching a maximum around 125 °C and decaying at higher temperatures. These results are the consequence of complex modifications occurring in the inorganic and organic bone structure. For lower temperatures dehydration, dehydroxilation, and carbonate loss processes are dominant, followed by collagen denaturing and decompositions, which have an influence on the bone microstructure.

Calcium carbonate is the most abundant inorganic material, and it was used to build the ancient Mayan monuments in the peninsula of Yucatan, Mexico. One of the most important challenges that these structures have to confront is related to water and its transport inside the stone that induces serious deterioration. In this study, the photoacoustic (PA) technique is used to monitor the water permeability of two kinds of solid and compacted powdered stones. The analysis of water permeability in stones is performed using a modified Rosencwaig PA cell. When the stones are in contact with the water reservoir, the PA signal amplitude is observed to decay gradually due to the progressive wetting of the sample. Based on this type of experiment, the water diffusion coefficients as well as the time evolution of the thermal effusivity are obtained.

Photoactivation of titanium oxide Degussa P25 in ethanol–methanol suspensions, with different molar ratios, was monitored in situ using a piezoelectric sensor. The process was studied in a specially designed cell in which the sample can be illuminated by a continuous UV Hg lamp to induce photoactivation. The evolution of the process was followed by sending a modulated red laser beam onto the sample positioned on top of a piezoelectric detector. The output voltage of the sensor is also modulated and its amplitude allows to follow the photoactivation process. In order to control the photoactivation process, the cell was fed with N 2 regulated flux. It is shown that when the sample is illuminated with a UV lamp, the amplitude of the piezoelectric signal falls gradually up to a value that remains constant. The amplitude of the photoactivation, the initial time and the velocity of photoactivation signal of titania are related to ethanol–methanol proportion. The mechanism associated with photoactivation and the role of ethanol–methanol proportion are discussed.

The antibacterial properties of silver modified montmorillonites from Pellegrini Lake, Argentina were tested in growth inhibition of Escherichia coli bacteria. Montmorillonite was first submitted to different treatments: (a) calcination at 550 °C for 3 h and (b) grinding during 300 s. After that, the samples were loaded with silver by ion exchange. Structural characterization was performed by X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FTIR), and BET specific surface area measurements. Scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTM) showed that metallic silver nanoparticles precipitates over the clay surface after silver modification. Nevertheless, the displacement of the (0 0 1) reflection observed by XRD in the calcined sample, and the diminution in Na + content evaluated by energy dispersive X-ray spectroscopy (EDXS), indicate that Ag ions were interchanged in the structure of the clays. Both samples showed good antibacterial activity against E. coli , measured by the disk susceptibility and the minimum inhibitory concentration (MIC) tests. The ground montmorillonite required a lower MIC than the thermally treated, although the last one presented a bigger inhibition zone in the disk method. The results shows that the antibacterial activity is generated by the Ag + present in the clay, as confirmed by X-ray photoelectronic spectroscopy (XPS); however the overall antibacterial properties are affected by the availability of the ionic silver to be in contact with the bacteria.

Calcium oxide and a mixed CaO(10)–SiO2(90) wt% sample were synthesized by sol–gel method, using HCl or HNO3 as hydrolysis catalysts. The powders were thermally treated at 200, 400, 600 and 800 °C. Sample characterization was carried out by X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) spectroscopy. The specific surface area and pore volume were measured by the BET method. For the pure samples, it was found that the crystalline phases and structural properties depend on the catalyst used during the synthesis; whereas the surface areas were similar in both cases. On the other hand, at high temperatures, the mixed CaO–SiO2 oxide showed glass-like properties, where CaO is dispersed in an amorphous phase.

Groundwater pollution by nitrates is a widespread problem in many locations in the world. The underground aquatic mantle of the Peninsula of Yucatan is highly vulnerable due to its karstic nature. Adsorption methods are a good choice for nitrate elimination. In this work, a natural calcium bentonitewas modified by acid thermoactivation with HCl and H2SO4, and tested as a media for nitrate removal in an aqueous solution. The nitrate concentration in the solution was measured by FT-IR, using the Lambert‐Beer law. Clay characterization was carried out by X-ray diffraction and FT-IR spectroscopy; surface area was measured by the BET method.

Seaweed waste (SWW) is a residue or by-product from the filtration step of the agar extraction process, and it has been explored as an inexpensive and effective filler for incorporation by melt blending into a poly(lactic acid) (PLA) matrix. PLA-SWW biocomposites were manufactured with various contents of SWW (0, 5, 10, 15, and 20 wt %) using a sheet extrusion process. PLA was functionalized with maleic anhydride (MAH) by reactive extrusion using dicumyl peroxide (DCP) as an initiator, and it was extruded using 0, 5, and 20 wt %. SWW content. The mechanical, thermal, structural, and morphological properties of the processed biocomposites were investigated. Regarding the mechanical behavior, a slight increase in the tensile modulus was observed at low SWW content. The thermal properties indicated that the rigid amorphous phase content was enhanced in the biocomposites. This work suggests that SWW can be used as filler to develop environmental friendly biocomposites. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42320.

Several compositions in the CaO-ZrO2 system were synthesized from zirconium n-butoxide and calcium methoxide, by the sol-gel method. Hydrolysis and gelation occurred at pH 3, using H2SO4 as hydrolysis catalyst. Fresh gels were annealed in air at 100 to 900°C, in 100°C steps every 20 h, for a total annealing time of 140 h. Analysis by X-ray diffraction showed the formation of hydrated calcium sulfate together with amorphous zirconia up to 400°C. At the ZrO2 rich-end, tetragonal and monoclinic zirconia solid solutions were stabilized in the presence of Ca ions. When 20 and 30 wt% of CaO were added, cubic zirconia and CaZrO3 solid solutions were observed above 700°C. At the CaO rich-end, the coexistence of calcium carbonate polymorphs as vaterite and calcite were observed. Anhydrite was present across the entire range of compositions studied from 300 to 900°C.

Sulfated and phosphated titania (TiO 2 ) were obtained by the sol–gel method. The sulfation was prepared in situ using sulfuric acid as hydrolysis catalyst, or by impregnation with ammonium sulphate. Phosphated sol–gel titania was synthesized with phosphoric acid. Long thermal treatments were carried out from 100 to 1000 °C to study the crystallization process of titania. All present phases were nanocrystalline, and the anatase–rutile polymorphic transformation was dependent on the crystallite size of the materials and on the preparation method. The smallest crystallite values were obtained for the phosphated samples. Titania sulfated by impregnation was found to be an efficient and selective catalyst towards propene, whereas di-isopropylether was obtained only in the catalyst prepared in situ with H 2 SO 4 .

The thermal properties of the marine shells of the mollusk Strombus gigas are studied using photoacoustic techniques. In order to generate changes in the layered structure of the shells, they were thermally treated in therange from ambient temperature up to 400°C. Our results show that the thermal diffusivity and conductivity have a maximum at 200°C due to the degradation of the organic matrix. At higher temperatures the thermal diffusivity and conductivity decrease due to the calcium carbonate structural phase transition from aragonite to calcite.

Mixtures of ZrO2-CaSO4 in different molar ratio were prepared by the sol–gel method. The precursors were anhydrous calcium sulfate (CaSO4) and zirconium n-butoxide in ethanol. Sulfuric acid was used as a hydrolysis catalyst to carry out the reaction at pH 3. The samples were thermally annealed and characterized by X-ray powder diffraction (XRD). Crystalline structure for selected samples (100, 90, 80% molar ZrO2), were refined by the Rietveld method. Tetragonal zirconia and anhydrite were obtained in all compositions ranges, from 400 up to 800°C, although baddeyelite appears in the zirconia rich end (98% molar) from 600°C. Towards high calcium content, different nanostructured calcium sulfates as gypsum, bassanite and anhydrite were obtained.

An alternative method to diminish the nitrogen pollutant levels in waste waters is to encapsulate microorganisms whitin ceramic materials. The sol–gel method has been extensively used for the preparation of such kind of materials permitting a higher stability and viability of useful organisms. In this work, the thermal characterization during dehydration of nitrifying and denitrifying aqueous emulsions of mud encapsulated in sol–gel silica is presented during the process of dehydration in ambient conditions and as a function of temperature. The characterization was performed by a photopyroelectric (PPE) technique, whose detector was made with a 110 mm polyvinyldifluoride (PVDF). The cell was constructed in such a way that the sample was inside the cell, and the bottom of the cell was closed by the PVDF foil. Thermal effusivity as a function of temperature was obtained illuminating the PVDF directly by a modulated 1W tungsten lamp. The sample is enclosed inside a chamber, using a Peltier cell that controls temperature in a range from 40 to 27 ◦ C. The sample is on top of the PVDF, which is illuminated by the modulated tungsten lamp.

Polycrystalline cadmium sulfide (CdS) thin films were deposited on glass substrates by chemical bath deposition (CBD) and close-spaced sublimation (CSS) techniques. The typical deposition temperatures between these techniques are quite different. The CdS thin films deposited by CBD were prepared using two methods of bath agitation: magnetic and ultrasonic agitation. We found that films deposited with ultrasonic agitation presented a cleaner surface with minor presence of contaminants, similar to the obtained for CSS films, as demonstrated by Auger analysis. Properties of the CdS films such as morphology, optical transmission, crystallinity and band gap energy, are discussed in order to compare them in both techniques. We obtain that crystallinity of CdS films depends strongly on the temperature used for deposition. In agreement with several works, films prepared by CBD technique presented a cubic structure, while films grown by CSS technique exhibited an hexagonal symmetry.

In this article the potential of photoacoustic techniques in the optical and thermal characterization of mollusk-made biominerals is explored. The case of two bivalve species with strong structural and architectural differences, oysters (Crassostrea virginica) and mussels (Ischadium recurvum) is considered. The difference between them is closely related to the dominance of different polymorphs of calcium carbonate in crystalline phases known as aragonite and calcite. The thermal diffusivity, visible and infrared absorption spectra, and x-ray analysis show differences between aragonite and calcite made biominerals. Photoacoustic spectra show absorption bands related to Fe, Mn, and organic pigments.

The role of the corrosion products in the inhibition of Zn alloy coating corrosion has not been considered fully to date. Atmospheric corrosion data on Zn, Zn-Fe, Zn-Co, and Zn-Ni electrodeposits exposure to marine and urban test sites of a humid, tropical climate during a 3-year period revealed that Zn-Ni and Zn-Co coatings are more resistant than Zn and Zn-Fe. Corrosion products formed on these samples have been characterized by x-ray diffraction (XRD) and x-ray photoelectron spectroscopy (XPS). Sodium chlorhydroxysulfate (NaZn4Cl[OH]6SO4·6H2O) and zinc hydroxychloride (Zn5[OH]8Cl2·H2O) were determined to be the main constituent compounds of corrosion films formed in both test sites. It is assumed that the amorphous structure and properties of the oxide phase may play an important role in determining coating corrosion resistance.