Incorporation of a tungsten Fischer-type metal carbene covalently bound to functionalized SBA-15

A metal Fischer carbene [(CO)₅WC(φ)OCH₂CH₃] was covalently linked for the first time to the silanol groups of the mesoporous channels of SBA15 by following two different synthetic anchoring routes. The first one goes through the reaction of the SBA15 mesoporous silica walls functionalized by aminopropyltriethoxysilane (APTES) with a tungsten carbene Wφ, while in the second approach a precursor synthesized by reacting APTES with the carbene Wφ is then anchored via a direct bond to the silanol groups in the interior pore channels of SBA-15.

This tethering is helpful to prevent the decomposition of the metallic complex. XRD, N₂ adsorption–desorption, and TEM analysis provide strong evidence that the mesoporous support structure retains its long-range ordering after the grafting process, despite a significant reduction of its specific surface area, pore-volume and pore-size. The chemical bonding of the tungsten carbene to the silanol groups of SBA-15 materials was studied with solid-state NMR spectroscopy. Both ¹³C MAS NMR and ²⁹Si CP MAS NMR spectra confirm the covalent linking of the carbene to the silica-pore system.     

Mitochondrial Mechanisms in Septic Cardiomyopathy

Sepsis is the manifestation of the immune and inflammatory response to infection that may ultimately result in multi organ failure. Despite the therapeutic strategies that have been used up to now, sepsis and septic shock remain a leading cause of death in critically ill patients. Myocardial dysfunction is a well-described complication of severe sepsis, also referred to as septic cardiomyopathy, which may progress to right and left ventricular pump failure. Many substances and mechanisms seem to be involved in myocardial dysfunction in sepsis, including toxins, cytokines, nitric oxide, complement activation, apoptosis and energy metabolic derangements. Nevertheless, the precise underlying molecular mechanisms as well as their significance in the pathogenesis of septic cardiomyopathy remain incompletely understood. A well-investigated abnormality in septic cardiomyopathy is mitochondrial dysfunction, which likely contributes to cardiac dysfunction by causing myocardial energy depletion. A number of mechanisms have been proposed to cause mitochondrial dysfunction in septic cardiomyopathy, although it remains controversially discussed whether some mechanisms impair mitochondrial function or serve to restore mitochondrial function. The purpose of this review is to discuss mitochondrial mechanisms that may causally contribute to mitochondrial dysfunction and/or may represent adaptive responses to mitochondrial dysfunction in septic cardiomyopathy.     

The influences of carcass weight and depot on the fatty acid composition of fats of suckling Manchego lambs

The effects of carcass weight (<5.5 kg, 5.5–6.5 kg, ⩾6.5 kg) of Manchego suckling lambs, type of fat depot of the leg (subcutaneous, intermuscular and intramuscular) and muscle (m. longissimus dorsi (LD) or m. quadriceps femoris (QF)) on the fatty acid composition were studied. Carcass fatness increased with increasing carcass weight. However, few differences in fatty acid proportion were observed between the three carcass weight groups. The lightest carcasses had lower proportions of myristic (C14:0) and palmitoleic (C16:1) acid and higher proportions of stearic (C18:0) acid, desirable fatty acids (DFA) (C18:0 + total unsaturated fatty acid (TUFA)) and a greater nutritive value ((C18:0 + C18:1)/C16:0). The fatty acid composition of subcutaneous and intermuscular fat depots of the leg were similar, whereas the intramuscular fat depot was different from both of these, since it had a lower proportion of saturated fatty acids (SFA), a greater proportion of TUFA, higher PUFA/SFA and n − 6/n − 3 ratios, and greater DFA and nutritive values. The intramuscular fat of the LD was more saturated than QF, higher SFA, and had lower value of PUFA/SFA ratio and DFA. These results indicated that the intramuscular fat quality of the leg was better than subcutaneous and intermuscular fat depots and also that intramuscular fat displayed better attributes of quality (lower SFA, higher TUFA, and greater PUFA/SFA ratio and DFA as well) than intramuscular fat of the LD from the consumer health standpoint. Despite carcass weight affected carcass fatness, it did not seem to influence the proportions of saturated or polyunsaturated fatty acids. For this reason, carcass weight probably had little effect on the organoleptic characteristics of the meat.     

A comparison of various rheological properties for modelling the kinetics of thermal softening of potato tissue (c.v. Monalisa) by water cooking and pressure steaming

The kinetics which can be used to describe thermal softening of potato tissue by water cooking and pressure steaming were established and the temperature dependence of rheological and textural properties, using six different instrumental objective methods as firmness indicators, was determined within the temperature range of 100–122 °C. In water cooking at 100 °C and in steaming at 100, 112 and 117 °C, the thermal softening was best expressed by one simple pseudo first-order kinetic mechanism, which was considered to be the response to the changes in the pectic material in the cell wall and interlamellar region. Tension energy was the best rheological property for establishing the kinetics of softening of potato by water cooking, whereas maximum shear force was the best method of representing the tissue softening by steaming, using first-order models. Steaming at 122 °C caused overcooking of the tissue, even for short times. At this high temperature, rheological parameters (compression, tension and creep compliance) and textural properties from Texture Profile Analysis (TPA) fitted second-order models. When second-order models were used, the Arrhenius equation was significant for chewiness, indicating that this textural property can be useful for detecting overcooking caused by prolonged pressure steaming in the experimental temperature range.     

The effect of the pre-treatments and the long and short-term frozen storage on the quality of raspberry (cv. Heritage)

Results are presented of the effect of pre-treatments before freezing followed by long and short-term frozen storage (12 months at –18 °C and 24 days suffering temperature fluctuations between –18 °C and –12 °C) on quality parameters of raspberry. Pre-treatments were carried out with calcium, low methoxyl pectin, a combined solution, and results compared with untreated control fruits. Kramer shear, back extrusion, compression, and multiple penetration tests were used to measure rheological behavior. One-hundred mM CaCl₂ reduced the long and short-term frozen storage induced loss of firmness. For long-term storage at –18 °C, a softening of the tissue became evident between 3 and 12 months and at each date test the stored fruits were firmer than those without storage. For short-term storage with fluctuations, the loss of firmness was evident between 0 and 24 days, and at all the testing dates the stored fruits were softer than those without storage. Results evidenced a higher cell damage in the short-term frozen storage. Coefficients of softening per day suffering fluctuation were determined, the highest values being given by Kramer shear energy and back extrusion maximum force (>1%). Short-term frozen storage affected physical and physico-chemical characteristics, increasing the saturation (r) and the anthocyanins and decreasing the ascorbic acid of the raspberries. In both storage conditions, pre-treatments reduced the drip loss, which correlated best with the Kramer shear energy. Panelists detected mainly time effect on the sensory firmness. For long-term, sensory firmness and juiciness gave the highest correlations with back extrusion maximum force, while for the short-term, sensory firmness and drip loss gave the highest correlations with the Kramer shear energy. SEM revealed different degrees of mechanical damage to structure, which accounted for rheological behavior of the fruits.     

Immunoadjuvant activity of oral Lactobacillus casei: influence of dose on the secretory immune response and protective capacity in intestinal infections.

Lactobacilli, often used as effectors of host functions, could play an important role in maintaining human health by controlling other intestinal microorganisms capable of producing harmful effects. Using an experimental model, we studied the effect of different oral doses of Lactobacillus casei on the secretory IgA response and the protective capacity of the microorganism in preventing intestinal infections. The optimization of the protective dose of Lb. casei by previous feeding and the use of the lactobacillus as an immunological way to control enteric infections were investigated. We found that conventional mice were protected against infection with Salmonella typhimurium and Escherichia coli by previous feeding for 2 consecutive days with a daily Lb. casei dose of 1.2 x 10(9) cfu/mouse. Previous feeding for 7 d proved less effective, and feeding for 5 d afforded no protection at all. We were also able to demonstrate that the protective effect of Lb. casei against Sal. typhimurium and Esch. coli was connected mainly with the high level of IgA antipathogen antibodies present in intestinal secretions. beta-Glucuronidase (EC 3.2.1.31) and beta-galactosidase (EC 3.2.1.23) activities, measured both in the intestinal fluid and histological samples, showed a marked increase in intestinal inflammatory response on day 5 of feeding. These results show that Lb. casei plays an important role in the prevention of enteric infections, a low dose being enough for protection against intestinal infections by increasing IgA secretion into the intestinal lumen, thus providing adequate defences for the mucosal surface. A previously administered dose of this magnitude could therefore be used as an oral adjuvant in preventing enteric infections.     

The Effect of Antibrowning Agents on Inhibition of Potato Browning,Volatile Organic Compound Profile,and Microbial Inhibition

Abstract: Burbank and Norkotah potato slices were dipped into 3% sodium acid sulfate (SAS), citric acid (CA), sodium erythorbate (SE), malic acid (MA), sodium acid pyrophosphate (SAPP), or a combination of SAS‐CA‐SE. Browning by polyphenol oxidase (PPO) obtained from potato extract with 0.04 to 0.016 g/mL of antibrowning solutions at pH 2.0 to 6.9 were measured by UV‐Vis spectroscopy. The color of slices dipped in antibrowning solutions at pHs 2 to 7 and stored at 4 °C for 15 d was measured every 5 d by colorimeter. Headspace analysis of volatiles in raw and cooked potato samples was performed by selected ion flow tube mass spectrometer (SIFT‐MS) and soft independent modelling by class analogy (SIMCA) analysis of the calculated odor activity values (OAV) determined interclass distances. Microbial growth was measured at 15 d. At unadjusted pHs (1.1 to 7.1), the PPO browning of the control and samples with SAPP was not significantly different, SAS, CA, and MA produced some inhibition and SE and SAS‐CA‐SE prevented browning. At pH 5 to 7, only SE and SAS‐CA‐SE were effective browning inhibitors. Based on the color of potato slices, SE was the most effective at pH 2 to 7, but SAS was most effective at unadjusted pH. Cooking increased volatile levels in the treated potatoes and decreased differences between volatile profiles. Differences between cooked samples may not be noticeable by the consumer because volatiles with high discriminating powers have low OAVs. SAS, CA, and SAS‐CA‐SE treatments inhibited microbial growth but SAPP, control, and SE did not, most likely due to pH. Practical Application: Antibrowning agents inhibit polyphenol oxidase, increasing shelf life and consumer acceptability of processed raw potato products by preserving the color. Their effectiveness was shown to be mainly due to a pH effect, except SE, which was not pH dependent. MA, CA, and SAS‐CA‐SE are better acidulants for inhibition of color change as well as growth of spoilage bacteria, yeast, and mold than SAPP, the industry standard.     

Biguanide-, imine-, and guanidine-based networks as catalysts for transesterification of vegetable oil

Polycationic systems based on poly(hexamethylene biguanide) (PHMBG), branched polyethyleneimine (PEI) and poly(N-vinylguanidine) (PVG) have been evaluated as heterogeneous catalysts for the transesterification of sunflower oil by methanol. Insoluble networks are synthesized via cross-linking of PHMBG by either 4,4′-methylenebis(N,N-diglycidylaniline) or polyisocyanate prepolymer, PEI with sebacoyl chloride, and PVG with 1,4-butanediol diglycidyl ether. PHMBG and its cross-linked networks appeared to be remarkably efficient catalysts, enabling 80–100% triglyceride conversion within 0.5 h at 70 °C. PEI-based networks catalyzed triglyceride transesterification with rates 8- to 12-fold slower than their PHMBG-based counterparts. The PVG-based networks, which were devoid of hydrophobic moieties, appeared to be inefficient catalysts due to limited accessibility of the basic guanidine groups to reactants. The PHMBG networks were shown to be recyclable by a simple centrifugal filtration. After 15 cycles of recovery and reuse, only 10–15% decline in performance was observed.     

Steel mill slags energy potential: the case of the steel factory of Arcelor-Mittal in Asturias (Spain)

Slag accounts for most of the residuals or by-products of the steel manufacturing process and represents a not inconsiderable amount of energy waste and CO₂ emissions. Energy recovery from steel mill slags is not actually performed because of the difficulty of the industrial implementation, but the actual demand and the incentives for new electricity generation plants based on renewable energies and on industrial waste heat recovery offer a new opportunity to evaluate the feasibility of this process. This article presents a review of the slag energy potential on a global scale, and a proposal for a recovery plant in the factories of Arcelor-Mittal in Asturias (Spain), based on a steam Rankine cycle for electricity production in a turbine. The plant production and viability have been analyzed using the typical technical and economic values for this kind of plant. Also, a parametric study has been performed on the heat recuperator efficiency and investment rate.