Mechanisms of enterohemorrhagic Escherichia coli spread along the food-chain and precautionary measures

Enterohemorrhagic Escherichia coli (EHEC) are food-borne pathogens implicated in large outbreaks and sporadic cases of bloody diarrhea and the hemolytic uremic syndrome. The main reservoir of EHEC is the intestinal tract of ruminants, in particular cattle. Feces containing these bacteria may act as a source of contamination for the environment and particularly for a variety of foods. E. coli O157:H7 as well as other EHEC-serotypes have been isolated from domestic ruminants and non-ruminant farm animals as well as products produced from them, but also from drinking water, vegetables and dairy products. The main transmission pathway of the pathogens is the ingestion of raw or undercooked contaminated food but human infection can also occur by person-to-person transmission. This article will focus on the prevalence and spread of EHEC by vegetable foods, especially the less common EHEC transmission sources sprouts and leafy greens. It will discuss precautionary measures against the spread of EHEC in food at all stages of the food chain: the primary production, the industrial processing, the retailing as well as the consumer.     

Impact of Trail Running Races on Blood Viscosity and Its Determinants: Effects of Distance

Blood rheology is a key determinant of tissue perfusion at rest and during exercise. The present study investigated the effects of race distance on hematological, blood rheological, and red blood cell (RBC) senescence parameters. Eleven runners participated in the Martigny–Combes à Chamonix 40 km race (MCC, elevation gain: 2300 m) and 12 others in the Ultra-Trail du Mont Blanc (UTMB, 171 km, elevation gain: 10,000 m). Blood samples were collected before and after the races. After the UTMB, the percentage of RBC phosphatidylserine (PS) exposure was not affected while RBC CD235a levels decreased and RBC-derived microparticles increased. In contrast, after the MCC, RBC PS exposure increased, while RBC CD235a and RBC-derived microparticles levels were not affected. The free hemoglobin and hemolysis rate did not change during the races. RBC aggregation and blood viscosity at moderate shear rates increased after the MCC. RBC deformability, blood viscosity at a high shear rate, and hematocrit decreased after the UTMB but not after the MCC. Our results indicate that blood rheology behavior is different between a 40 km and a 171 km mountain race. The low blood viscosity after the ultra-marathon might facilitate blood flow to the muscles and optimize aerobic performance.     

燃气轮机性能试验用的康氏水力测功器

一个多世纪以来,水力测功器一直是测量和诊断发动机性能的重要设备。由于较诸电力与气动机械具有若干固有优点（如单位造价较低,尺寸紧凑,惯性小,快速瞬态响应以及在高转速和大功率工况下的运行能力）,水力测功器已经成为航空及工业用和船用燃气轮机发动机进行研制、耐久性、生产性试验和维修后试验用的一致公认的标准手段。电子式快速响应涡轮控制系统的应用更是加快了这一趋势,因为这对动态试验程序提出了更高要求。     

A Simple In Vitro Fermentation System for Polysaccharides—The Effects of Fermenter Fluid Surface Area/Fluid Volume Ratio and Amount of Substrate

A simple batch fermentation system for dietary non-starch polysaccharides using simple in vitro methods has been studied to identify if the position of the bottle (fluid surface area/fluid volume ratio) and shaking influence fermentation and bacterial mass. Shaking has no effect on the fermentation or bacterial mass increase. The amount of pectin, ispaghula or starch influences the result as does the surface to volume ratio. © 1997 SCI.     

Synthesis and Biological Evaluation of Fluorescent Bryostatin Analogues

To investigate the cellular distribution of tumor‐promoting vs. non‐tumor‐promoting bryostatin analogues, we synthesized fluorescently labeled variants of two bryostatin derivatives that have previously shown either phorbol ester‐like or bryostatin‐like biological activity in U937 leukemia cells. These new fluorescent analogues both displayed high affinity for protein kinase C (PKC) binding and retained the basic properties of the parent unlabeled compounds in U937 assays. The fluorescent compounds showed similar patterns of intracellular distribution in cells, however; this argues against an existing hypothesis that various patterns of intracellular distribution are responsible for differences in biological activity. Upon further characterization, the fluorescent compounds revealed a slow rate of cellular uptake; correspondingly, they showed reduced activity for cellular responses that were only transient upon treatment with phorbol ester or bryostatin 1.     

The use of nickel oxide as a hole transport material in perovskite solar cell configuration: Achieving a high performance and stable device

Solar cells incorporated with organic-inorganic lead or tin halide-based perovskite materials as active light-absorber surfaces are referred to as perovskite solar cells (PSCs). This fast advancing solar technology has recorded an increase in its efficiency from 3.8% in 2009 to above 25% in recent years. The technology creates room for diverse device architectures, which enhances further development of thin-film solar cells and photovoltaics. This article reviews the use of nanocrystalline nickel oxide (NiO) film as a hole transport material in PSCs. The literature on pure nickel oxide and doped nickel oxide films has been discussed. The principle of operation, charge separation of PSCs and the various parameters that affect the efficient hole transport mechanisms, power conversion efficiency, growth mechanism, and stability of PSCs have also been discussed. Possible electron-blocking applications and future perspective of nickel oxide films have also been discussed.     

In silico Support for Eschenmoser’s Glyoxylate Scenario

A core topic of research in prebiotic chemistry is the search for plausible synthetic routes that connect the building blocks of modern life, such as sugars, nucleotides, amino acids, and lipids to “molecular food sources” that were likely to have been abundant on early Earth. In a recent contribution, Albert Eschenmoser emphasised the importance of catalytic and autocatalytic cycles in establishing such abiotic synthesis pathways. The accumulation of intermediate products furthermore provides additional catalysts that allow pathways to change over time. We show here that generative models of chemical spaces based on graph grammars make it possible to study such phenomena in a systematic manner. In addition to reproducing the key steps of Eschenmoser’s hypothesis paper, we discovered previously unexplored potentially autocatalytic pathways from HCN to glyoxylate. A cascade of autocatalytic cycles could efficiently re-route matter, distributed over the combinatorial complex network of HCN hydrolysation chemistry, towards a potential primordial metabolism. The generative approach also has it intrinsic limitations: the unsupervised expansion of the chemical space remains infeasible due to the exponential growth of possible molecules and reactions between them. Here, in particular, the combinatorial complexity of the HCN polymerisation and hydrolysation networks forms the computational bottleneck. As a consequence, guidance of the computational exploration by chemical experience is indispensable.