Recent developments in graphene-based polymer composite membranes: Preparation,mass transfer mechanism,and applications

The shortage of water resources is a problem concerned by all countries in the world. In order to solve this problem of human survival, membrane separation technology promotes the development of water treatment field by virtue of its own advantages of high efficiency and low consumption. Membrane separation technology combined with nanomaterials has brought surprises to researchers. Graphene has unique structure and properties, making graphene and its derivatives have very good potential in water treatment and selective separation. Graphene-based materials combined with traditional polymer materials have great potential in the field of membrane separation technology. In this article, we first introduce the preparation methods and transport mechanism of graphene-based membranes, and then summarize the recent applications of graphene oxide/polymer composite membranes in water purification, gas separation, self-cleaning, and oil–water separation. It is expected to become the next generation of functional composite membranes. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47761.     

Investigation of neonatal brain cytochrome redox by NIRS

Near Infrared Spectroscopy (NIRS) has been used to detect changes in cerebral blood and tissue oxygenation. Redox state of enzyme cytochrome aa3 (Cyt aa3 is thought to give an indication of tissue oxygenation. This information would be of value in exploring the aetiology of cerebral ischaemic lesions in preterm infants. However we have found that the change in cerebral cytochrome redox in infants following desaturation was inconsistent and insignificant.     

Thermodisplacement imaging of current in thin-film circuits

We present initial results on a novel scheme for measuring current distribution in thin-film circuits. When an AC current passes through a thin-film circuit, the resulting periodic heating sets up a dynamic surface displacement which can be detected using a phase-sensitive laser probe. Results indicate that the present system has a sensitivity of 4 × 10?3 ? for displacement and 2.7 × 10?2°C for temperature in a 1 Hz bandwidth. The spatial resolution can be as small as an optical wavelength and is currently limited to 2 ?m by the optics used. As the surface displacement amplitude depends on the thermal properties of the substrate material, the technique can also be used to detect defects beneath the metallisation in integrated-circuit structures.     

Scanning acoustic microscopy: a review

The main features of the scanning acoustic microscope are reviewed with particular reference to applications in biology and non-destructive evaluation. Recent developments on imaging the interior of solids are discussed. Proper interpretation of recorded images can lead to maps of velocity and density via the V(z) response. Further improvements in resolving power (using cryogenic liquids or high pressure gases) should make the acoustic microscope a powerful tool in many areas of science and technology.     

核糖体脱嘌呤分析法分析检测核糖体失活蛋白

针对核糖体脱嘌呤分析法经常被用来分析检测新的核糖体失活蛋白(RIP),检测了由酸性苯胺催化在RIP催化脱嘌呤位点断裂产生的核糖体rRNA片段。利用文献发表的一级动力学速度常数,计算分析了核糖体失活蛋白含量对核糖体失活蛋白催化脱嘌呤分析的敏感性,并进行了部分实验验证。实验中核糖体失活蛋白和核糖体溶液混合后进行了30 min的恒温培养,结果表明:核糖体失活蛋白脱嘌呤分析法的敏感性取决于核糖体失活蛋白催化核糖体脱嘌呤反应的速度常数。还分析了核糖体失活蛋白脱嘌呤分析中可能出现的假阳性和假阴性结果及其原因,结果表明:在核糖体失活蛋白的大规模生产中使用核糖体脱嘌呤分析法作为定量分析的手段是比较复杂和困难的,该方法应该和一些常用的经典方法例如SDS PAGE分析法联合使用,而且联合使用时两种方法的最小检测限应该相近,以避免其中之一引起的假阳性结果。     

The Predominance of Psychrotrophic Pseudomonads on Aerobically Stored Chilled Red Meat

Microbial spoilage of meat during chilled aerobic storage causes significant financial losses to the industry. Even with modern day preservation techniques, spoilage remains an unsolved problem. Spoilage of meat is a complex process that involves the activity of endogenous enzymes and microorganisms. Psychrotrophic Pseudomonas species are the key microorganisms that cause spoilage in aerobically stored chilled meat. Spoilage pseudomonads are highly robust and able to withstand stressful environmental conditions that would otherwise inhibit the growth of other spoilage organisms. In order to implement efficient control measures, and to minimize spoilage, a thorough understanding of the characteristics of spoilage pseudomonads is essential. This review focuses on the spoilage process and the key metabolic attributes of the main psychrotrophic spoilage Pseudomonas species to explain their predominance on meat over other psychrotrophic bacteria. This review also highlights less studied, but important, characteristics of psychrotrophic pseudomonads such as biofilm formation and quorum sensing in the context of meat spoilage. The importance of the use of model systems that are closely applicable to the food industry is also discussed in detail.     

Surface quality evaluation of 0.2 % C and AISI 304 steels in turning with sustainable lubricating condition

Journal of Mechanical Science and Technology - Metal working fluid (MWF) plays a significant role in metal machining operations to obtain the desired dimensional accuracy and better surface quality...     

Ultra-high-density phase-change storage and memory

Phase-change storage is widely used in optical information technologies (DVD, CD-ROM and so on), and recently it has also been considered for non-volatile memory applications. This work reports advances in thermal data recording of phase-change materials. Specifically, we show erasable thermal phase-change recording at a storage density of 3.3 Tb inch(-2), which is three orders of magnitude denser than that currently achievable with commercial optical storage technologies. We demonstrate the concept of a thin-film nanoheater to realize ultra-small heat spots with dimensions of less than 50 nm. Finally, we show in a proof-of-concept demonstration that an individual thin-film heater can write, erase and read the phase of these storage materials at competitive speeds. This work provides important stepping stones for a very-high-density storage or memory technology based on phase-change materials.     

Effect of Turbulence of the Freeboard on Fluidized-Bed Biomass Combustion

Fluidized-bed combustion is a very popular technology used to convert solid biomass into thermal energy, which has many advantages over other conversion technologies. However, these advantages strongly depend on the freeboard combustion. This study focuses on the effect of turbulence of the freeboard via developing a comprehensive mathematical model including four-way coupling, biomass thermal decomposition, and turbulent combustion by means of an Eulerian-Lagrangian framework. The validated model predicts with significant accuracy for all gas species when turbulence modeling is improved. The optimum amount of the secondary air ratio and the optimum excess air ratio were determined, which give a higher freeboard temperature while maintaining minimum emission.     

Variants in the pregnancy-associated plasma protein-A2 gene on Bos taurus autosome 16 are associated with daughter calving ease and productive life in Holstein cattle

Reproductive disorders in dairy herds have a negative effect on farm profitability and sustainability of milk production. Given the substantial evidence of the role of the pregnancy-associated plasma protein (PAPP) gene family in the regulation of reproduction in humans and mice, its role in insulin-like growth factor metabolism, quantitative trait loci effects in the mouse, and location of a calving ease QTL on bovine chromosome 16, the PAPP-A2 gene was chosen as a candidate gene to perform an association study for reproductive health in cattle. Single nucleotide polymorphisms (SNP) were identified in coding and conserved noncoding regions of the PAPP-A2 gene in 3 dairy breeds. A total of 7 tag SNP were genotyped in 662 Holstein bulls (UCD-bulls) to perform marker trait association analysis. Three SNP (SNP 13, 15, and 16) were in strong linkage disequilibrium in Holsteins, showing significant positive associations with daughter calving ease, productive life, milk yield, and protein yield. These results were validated by genotyping SNP15 in a larger population of 992 bulls from the cooperative dairy DNA repository (CDDR-bulls). Our results demonstrate that the PAPP-A2 gene is associated with reproductive health in Holstein cattle and that the identified SNP can be used as genetic markers in dairy breeding due to their positive association with reproductive and productive traits. Functional studies need to be conducted to identify the mechanisms for the association of SNP with these traits.