1D/2D Cobalt‐Based Nanohybrids as Electrocatalysts for Hydrogen Generation

The synergistic effects derived from optimizing the chemical and structural features of electrocatalysts permit them to attain remarkable activity and stability. Herein, 1D/2D cobalt‐based nanohybrid (CoNH) electrodes are developed; the structural design consists of Co₃O₄ electrospun nanoribbons (NRs) deposited onto a carbon fiber paper substrate where Co₃O₄ nanosheets are subsequently grown via an electrodeposition step and UV/ozone treatment. The content of noncovalently functionalized carbon nanotubes within the Co₃O₄ NRs is first tuned to enhance their charge transfer properties and mechanical stability. The electrocatalytic activity of the electrodes is further improved by a phosphorus modification of the 1D NRs, resulting in the formation of NaCoPO₄. The optimized 1D/2D CoNH electrode, i.e., ED‐0.09 wt% fCNTs/P‐CoNHs, displays a similar performance to that of platinum in 0.25 m Na₂S/0.35 m Na₂SO₃ (Tafel slope ≈102 mV dec^?1 for the former and ≈96 mV dec^?1 for the latter) and outstanding stability for up to 48 h. The versatility and high activity of this electrode is also demonstrated according to tests in a conventional water splitting system (cell voltage 1.55V, to produce 10 mA cm^?2) and a solar‐driven electrolyzer (1 m KOH).     

Profiles of volatile compounds in milk containing fish oil analyzed by HS‐SPME‐GC/MS

Long‐chain polyunsaturated fatty acids (LC‐PUFA) have various positive biological effects. Fish oil represents a major source of LC‐PUFA; therefore it is extensively used to enrich food products as, for example, infant formulae, dairy products and fruit juices. However, in the presence of oxygen and metals, LC‐PUFA readily degrade, producing off‐flavors and decreasing the nutritional value of the product. The deterioration of sensory properties (taste and odor) can be easily perceived by the consumer, due to the formation of volatile compounds that are formed by decomposition of lipid hydroperoxides, also known as primary oxidation products. In this study, we used the headspace solid‐phase microextraction‐gas chromatography/mass spectrometry technique (HS‐SPME‐GC/MS) to characterize and quantify volatile compounds in a food matrix supplemented with fish oil. We demonstrated that the HS‐SPME‐GC/MS method is a valuable tool to monitor lipid oxidation at early stages. We identified t‐2‐hexenal and c‐4‐heptenal as possible oxidation markers during the storage of milk enriched with 5% of cod oil.     

Novel semi-interpenetrated networks based on collagen-polyurethane-polysaccharides in hydrogel state for biomedical applications

The development of collagen hydrogels with tailored properties for improved applications in biomedicine represents an area of opportunity for materials science. The collagen can form semi-interpenetrated networks (semi-IPN) with various natural and/or synthetic polymers. This work aims the preparation of novel hydrogels generated from a collagen matrix cross-linked with polyurethane (PU), and the subsequent inclusion of polysaccharide chains to form semi-IPN systems with improved properties. The choice of polysaccharides for this purpose is related to their ability to modulate the biocompatibility and the antibacterial capacity in various biomedical strategies. The work contemplates to study the effect of the chemical structure of polysaccharide (hydroxyethylcellulose (HEC), hydroxypropylmethylcellulose (HPMC) or starch (Alm)) on the properties of these novel hydrogels. The results indicate that the semi-IPN hydrogels that include Alm exhibit the formation of stronger intermolecular interactions promoted by hydrogen bonds than HEC and HPMC, significantly improving the mechanical properties and their degradation rate in acidic, alkaline, and proteolytic media; also showing high capacity to inhibit the growth of E. colli. The semi-IPN hydrogels based on HEC and HPMC exhibit excellent improvement in both thermal and proteolytic degradation, compared with the collagen-PU matrix. On the other hand, this semi-IPN system does not present cytotoxic character for monocytes and fibroblasts growing for up to 48 h of culture. Therefore, these innovative 3D matrices will be excellent candidates with potential application in biomedical strategies such as wound healing dressings.     

Characterization of the human iris spectral reflectance with a multispectral imaging system

We present a multispectral system developed and optimized for measurement of the spectral reflectance and the color of the human iris. We tested several sets of filters as acquisition channels, analyzed different reconstruction algorithms, and used different samples as training sets. The results obtained show that a conventional three-channel color camera (RGB) was enough to reconstruct the analyzed reflectances with high accuracy, obtaining averaged color differences of around 2-3 CIEDE2000 units and root mean square errors of around 0.01. The device developed was used to characterize 100 real irises corresponding to 50 subjects, 68 prostheses used in clinical practice, and 17 cosmetic colored contact lenses.     

Technical and economic comparison of conventional and electrochemical coagulation processes

BACKGROUND: Electrocoagulation is an alternative to the conventional coagulation method, to treat different types of waters and wastewaters. Although there have been many reports on the technical suitability of electrocoagulation, no study has made a direct comparison of the economics of the two processes. RESULTS: Concerning the technical feasibility, no significant differences were found in the results achieved by the two technologies in the treatment of synthetic suspensions, emulsions and solutions of dyes, when the same values of pH and aluminium concentration were adopted in the reaction systems. Regarding the economic comparison, the electrocoagulation process presents lower operating costs for low and intermediate aluminium doses, but results depend on the particular coagulant reagent selected at high doses. The highest operational costs were obtained with conventional coagulation with aluminium sulphate (in the range 3–60 mg dm^?3 aluminium). Comparing electrocoagulation and conventional coagulation with aluminium polychloride, the electrocoagulation process presents lower operational costs for low and intermediate doses. However, this situation changes for high aluminium doses. CONCLUSION: Coagulation and electrocoagulation techniques give very similar yields in the removal of different types of pollutants; therefore an economic comparison is of major importance in order to recommend the use of one of the technologies. Nevertheless, it has to be noted that operational costs are of the same order of magnitude for the two processes. Thus, the cost of the electrocoagulation process compares favourably with that of conventional coagulation for small coagulant demands, but the results at high doses depend on the particular coagulant reagent selected. Copyright © 2008 Society of Chemical Industry     

Characterization of basaltic tuffs and their applications for the production of ceramic and glass–ceramic materials

Alkaline basaltic tuffs, from Southern Turkey were characterized and employed to obtain ceramic and glass–ceramic materials by combined sintering and crystallization process. The chemical and mineralogical compositions were analyzed by X-ray fluorescence spectrometry and X-ray diffraction analyses, respectively. The phase formation and the sintering behaviour were investigated by DTA, differential dilatometer and hot-stage microscopy. The micro-structure and residual porosity of the sintered samples were observed by SEM and evaluated by pycnometric techniques. Ceramic material, based on 50% basaltic tuff and 50% clay, was obtained at 1150 °C with 13% total porosity and 4% water absorption. Glass–ceramic materials were synthesized directly using the milled basaltic tuff by mean of the sinter-crystallization technique, in the range 900–1150 °C. The investigation has showed that, due to the high porosity and low crystallinity, alkaline tuffs could be a suitable raw material for ceramic application.     

Thermal degradation of long‐chain polyunsaturated fatty acids during deodorization of fish oil

Long‐chain polyunsaturated fatty acids (LC‐PUFA) of the n‐3 series, particularly eicosapentaenoic (EPA) and docosahexaenoic (DHA) acid, have specific activities especially in the functionality of the central nervous system. Due to the occurrence of numerous methylene‐interrupted ethylenic double bonds, these fatty acids are very sensitive to air (oxygen) and temperature. Non‐volatile degradation products, which include polymers, cyclic fatty acid monomers (CFAM) and geometrical isomers of EPA and DHA, were evaluated in fish oil samples obtained by deodorization under vacuum of semi‐refined fish oil at 180, 220 and 250 °C. Polymers are the major degradation products generated at high deodorization temperatures, with 19.5% oligomers being formed in oil deodorized at 250 °C. A significant amount of CFAM was produced during deodorization at temperatures above or equal to 220 °C. In fact, 23.9 and 66.3 mg/g of C20 and C22 CFAM were found in samples deodorized at 220 and 250 °C, respectively. Only minor changes were observed in the EPA and DHA trans isomer content and composition after deodorization at 180 °C. At this temperature, the formation of polar compounds and CFAM was also low. However, the oil deodorized at 220 and 250 °C contained 4.2% and 7.6% geometrical isomers, respectively. Even after a deodorization at 250 °C, the majority of geometrical isomers were mono‐ and di‐trans. These results indicate that deodorization of fish oils should be conducted at a maximal temperature of 180 °C. This temperature seems to be lower than the activation energy required for polymerization (intra and inter) and geometrical isomerization.     

Biopolymer films and the effects of added lipids,nanoparticles and antimicrobials on their mechanical and barrier properties: a review

Packaging made from biodegradable biopolymers such as proteins, polysaccharides and lipids is a promising alternative to synthetic polymers. Films made from these biopolymers exhibit certain disadvantages in terms of their mechanical, barrier and physicochemical properties. Plasticisers, nanoparticles, lipids and antimicrobial compounds can be added to them to improve these properties. The tendency of biopolymer films to brittleness can be mitigated by adding plasticisers and/or nanoparticles. These films also tend to have high water vapour permeability, which can be reduced by adding lipids and/or nanoparticles. Incorporating natural compounds with antimicrobial activity into biopolymer films can provide them the advantages of maintaining food safety and extending shelf life. Addition of plasticisers, nanoparticles, lipids and/or antimicrobial compounds to biopolymer films can help to make them comparable to conventional synthetic films with the advantages that they reduce pollution and are biodegradable.     

A Short Note on Steady State Behaviour of a Petlyuk Distillation Column by Using a Non‐Equilibrium Stage Model

A Petlyuk distillation column, considering equilibrium and non‐equilibrium stage models, was studied. Rigorous simulations were conducted using Aspen Plus? RATEFRAC Module for the separation of ternary mixtures. According to the equilibrium model, the energy‐efficient design of the Petlyuk column requires that the intermediate component be extracted from the maximum point in the composition profile in the main column. It was found that, for the intermediate component, mass transfer occurs from the vapour to the liquid phase from the top of the column to the stage where the side stream is extracted, from this point mass transfer occurs in the opposite direction. This point, considering the non‐equilibrium model, corresponds to the stage in which the net mass transfer rate is zero. For the case of two segments per stage, it was found that the heat duties predicted by the equilibrium model are significantly lower than those obtained by using the non‐equilibrium model, which is consistent with previous reported results. However, it is important to say that despite the higher energy duty predicted by the non‐equilibrium model; both models predict significant energy savings.     

Fish Oil Supplementation Improves Neutrophil Function During Cancer Chemotherapy

Cancer chemotherapy is associated with neutropenia and impaired neutrophil function. This study aimed to investigate whether supplementation with low dose fish oil (FO), providing n-3 polyunsaturated fatty acids, in cancer patients receiving chemotherapy after surgical tumor (mainly gastrointestinal) removal is able to improve the function of blood neutrophils. Patients (n?=?38) receiving chemotherapy (5-fluorouracil and leucovorin) were randomized into two groups; one group (control) did not receive a supplement, while the other group (FO) received 2?g FO/day for 8?weeks; the FO provided 0.3?g eicosapentaenoic acid plus 0.4?g docosahexaenoic acid per day. Patients in the control group lost an average of 2.5?kg of weight over the 8?weeks of the study. The number of blood polymorphonuclear cells (PMNC), mainly neutrophils, and their functions (phagocytosis and hydrogen peroxide production) decreased in the control group (average decreases of approximately 30, 45 and 17%, respectively). FO prevented these decreases and actually increased body weight (average of 1.7?kg weight gain; p?相似文献