Biological activity of camel milk casein following enzymatic digestion

The aim of this study was to investigate the effects of enzymatic hydrolysis with digestive enzymes of camel whole casein and beta-casein (β-CN) on their antioxidant and Angiotensin Converting Enzyme (ACE)-inhibitory properties. Peptides in each hydrolysate were fractionated with ultra-filtration membranes. The antioxidant activity was determined using a Trolox equivalent antioxidant capacity (TEAC) scale. After enzymatic hydrolysis, both antioxidant and ACE-inhibitory activities of camel whole casein and camel β-CN were enhanced. Camel whole casein and β-CN showed significant ACE-inhibitory activities after hydrolysis with pepsin alone and after pepsinolysis followed by trypsinolysis and chymotrypsinolysis. Camel β-CN showed high antioxidant activity after hydrolysis with chymotrypsin. The results of this study suggest that when camel milk is consumed and digested, the produced peptides start to act as natural antioxidants and ACE-inhibitors.     

Nanocomposite pyrite-greigite reactivity toward Se(IV)/Se(VI)

A nanopyrite/greigite composite was synthesized by reacting FeCl(3) and NaHS in a ratio of 1:2 (Wei et al. 1996). Following this procedure, the obtained solid phases consisted of 30-50 nm sized particles containing 28% of greigite (Fe(2+)Fe(3+)(2)S(4)) and 72% pyrite (FeS(2)). Batch reactor experiments were performed with selenite or selenate by equilibrating suspensions containing the nanosized pyrite-greigite solid phase at different pH-values and with or without the addition of extra Fe(2+). XANES-EXAFS spectroscopic techniques revealed, for the first time, the formation of ferroselite (FeSe(2)) as the predominant reaction product, along with elemental Se. In the present experimental conditions, at pH 6 and in equilibrium with Se(0), the solution is oversaturated with respect to ferrosilite. Furthermore, thermodynamic computations show that reaction kinetics likely played a significant role in our experimental system.     

Advanced fabrication and characterization of epitaxial ferroelectric thin films and multilayers

Understanding the behavior of ferroelectrics on the nanoscale level requires the production of materials of the highest quality and advanced characterization techniques for probing the fascinating properties of these systems with reduced dimensions. Here we give an overview of our recent achievements in this area, which includes the detailed study of the suppression of ferroelectricity in PbTiO3 thin films, the fabrication of PbTiO3/SrTiO3 superlattices in which ferroelectricity shows some surprising behavior, and finally the manipulation of nanoscale ferroelectric domains using the atomic force microscope which leads to the precise analysis of domain wall creep and roughness in Pb(Zr,Ti)O3 thin films.     

Swelling properties and bioactivity of silica gel/pHEMA nanocomposites

A novel hydrogel based on 2-hydroxyethyl- methacrilate and SiO₂ nanoparticles was prepared. The filler was added at a concentration of 30% w/w of silica nanoparticles to the mass of polymer. The composite material was characterised as far as concerns swelling behaviour in comparison to pHEMA. Swelling ratio of modified pHEMA was higher. Bioactivity of both SiO₂ nanoparticles and the modified hydrogel was evaluated by soaking samples into a simulated body fluid (SBF). FT-IR spectroscopy, scanning electron microscopy (SEM) and energy dispersive system (EDS) results suggest silica nanoparticles keep bioactive in the polymer. SiO₂ filler in a p(HEMA) matrix makes the composite bioactive. Therefore, these composites can be used to make bioactive scaffold for bone engineering.     

Rogue-base station detection in WiMax/802.16 wireless access networks

We address the problem of detecting a rogue base station (Bs) in WiMax/802.16 wireless access networks. A rogueBs is a malicious station that impersonates a legitimate access point (Ap). The rogueBs attack represents a major denial-of-service threat against wireless networks. Our approach is based on the observation that inconsistencies in the signal strength reports received by the mobile stations (Mss) can be seen if a rogueBs is present in a network. These reports can be assessed by the legitimate base stations, for instance, when a mobile station undertakes a handover towards anotherBs. Novel algorithms for detecting violations of received signal strength reports consistency are described in this paper. These algorithms can be used by an intrusion detection system localized on the legitimateBss or on a global network management system operating theBss.     

ST看好2022年智慧出行、电源和能源、物联网的机会

12021年回顾 对许多行业,尤其 是半导体行业来说,2021年都是前所未有的一年,是充满挑战的一年.这场席卷全球的芯片短缺主要与受疫情初期影响后经济的快速复苏有关,但也与我们专注的汽车和工业两个市场正在经历的变革有关.     

Bacterial Bioconversion of Primary Aliphatic and Aromatic Alcohols into Acids: Effects of Molecular Structure and Physico-chemical Conditions

The biotransformation of four alcohol substrates (butanol, 2-methylbutanol, 3-methylbutanol and 2-phenylethanol) into their acids was studied using a strain of Acetobacter aceti. Bioconversion yields depended on the molecular structure of the alcohol. Biotransformation of high concentrations of alcohols was possible until the precursor reached an inhibiting concentration (3·8 g dm⁻³ for butanol and 3-methylbutanol, 4·2 g dm⁻³ for 2-methylbutanol). In contrast, biotransformation of 2-phenylethanol decreased when alcohol concentration was higher than 0·3 g dm⁻³. Dissolved oxygen concentrations and pH conditions of the medium were important factors in improving bioconversion. Transformation of 2-methylbutanol into the corresponding acid was increased when dissolved oxygen partial pressure increased from 60 to 80% and regulation at pH 6 allowed an increase in the production of butyric acid from butanol. © 1997 SCI.     

Evaluating two kinds of centrifuged virgin oils arising from continuous olive processing

Oils extracted from olive pastes by the direct centrifugation mode were compared with the homologous oils produced by the indirect centrifugation (after percolation) mode. The former were characterised by: (i) higher contents of total phenols, o‐diphenols, hydroxytyrosol, hydroxytyrosol‐aglycons, total volatiles, trans‐2‐hexanal and other pleasant volatiles, total tocopherols, total sterols and waxes; (ii) lower contents of triterpene dialcohols, aliphatic and triterpene alcohols, chlorophylls and pheophytins; (iii) lower values of integral colour index; (iv) higher values of turbidity, campesterol/stigmasterol ratio, 1,2‐diglycerides/1,3‐diglycerides ratio, oxidative stability and overall quality indices; and (v) higher sensory score. Stigmastadienes and trans‐isomer C₁₈ fatty acids were always not detected. The average oil outputs of the two centrifugation extraction procedures were comparable, as confirmed by similar overall oil amounts found in the by‐products. © 2000 Society of Chemical Industry     

Cloning and characterization of the peroxisomal acyl CoA oxidase ACO3 gene from the alkane-utilizing yeast Yarrowia lipolytica

The ACO3 gene, which encodes one of the acyl-CoA oxidase isoenzymes, was isolated from the alkane-utilizing yeast Yarrowia lipolytica as a 10 kb genomic fragment. It was sequenced and found to encode a 701-amino acid protein very similar to other ACOs, 67·5% identical to Y. lipolytica Aco1p and about 40% identical to S. cerevisiae Pox1p. Haploid strains with a disrupted allele were able to grow on fatty acids. The levels of acyl-CoA oxidase activity in the ACO3 deleted strain, in an ACO1 deleted strain and in the wild-type strain, suggested that ACO3 encodes a short chain acyl-CoA oxidase isoenzyme. This narrow substrate spectrum was confirmed by expression of Aco3p in E. coli. © 1998 John Wiley & Sons, Ltd.