Internal benchmarking improves precision and reduces animal requirements for determination of fish bioconcentration factors

The enactment of new chemical regulations has generated a large need for the measurement of the fish bioconcentration factor (BCF). Past experience shows that the BCF determination lacks precision, requires large numbers of fish, and is costly. A new protocol was tested that shortens the experiment from up to 12 weeks for existing protocols to 2 weeks and reduces the number of fish by a factor of 5, while introducing internal benchmarking for the BCF determination. Rainbow trout were simultaneously exposed to 11 chemicals. The BCFs were quantified using one of the test chemicals, musk xylene, as a benchmark. These were compared with BCFs measured in a parallel experiment based on the OECD 305 guideline. The agreement was <20% for five chemicals and between 20%-25% for two further, while two chemicals lay outside the BCF operating window of the experiment and one was lost due to analytical difficulties. This agreement is better than that observed in a BCF Gold Standard Database. Internal benchmarking allows the improvement of the precision of BCF determination in parallel to large reduction in costs and fish requirements.     

Bottom-emission organic light-emitting diodes using semitransparent anode electrode by O2 plasma

To improve the performance of bottom-emission organic light-emitting diodes (BEOLEDs), the effect of oxygen plasma treatment duration on the electrical properties of multi-metal Ni/Ag/Ni thin film anode was investigated. The results revealed that a Ni/Ag/Ni thin-film layer formed upon oxygen plasma treatment for 60 s. Our indium-free bottom-emission OLEDs effectively increased the electrical and optical properties by improving their electron–hole recombination and doing a strong micro-cavity effect with the semitransparent multi-metal anode. The green bottom-emission OLEDs show a luminance of 14,280 cd/m², a luminous efficiency of 8.5 cd/A, external quantum efficiency 2.6% EQE, a Commission Internationale de L’Eclairage coordinates of (0.32, 0.58) on flexible substrate.     

Oxygen Ion Drift‐Induced Complementary Resistive Switching in Homo TiOx/TiOy/TiOx and Hetero TiOx/TiON/TiOx Triple Multilayer Frameworks

Developing a means by which to compete with commonly used Si‐based memory devices represents an important challenge for the realization of future three‐dimensionally stacked crossbar‐array memory devices with multifunctionality. Therefore, oxide‐based resistance switching memory (ReRAM), with its associated phenomena of oxygen ion drifts under a bias, is becoming increasingly important for use in nanoscalable crossbar arrays with an ideal memory cell size due to its simple metal–insulator–metal structure and low switching current of 10–100 μA. However, in a crossbar array geometry, one single memory element defined by the cross‐point of word and bit lines is highly susceptible to unintended leakage current due to parasitic paths around neighboring cells when no selective devices such as diodes or transistors are used. Therefore, the effective complementary resistive switching (CRS) features in all Ti‐oxide‐based triple layered homo Pt/TiO_x/TiO_y/TiO_x/Pt and hetero Pt/TiO_x/TiON/TiO_x/Pt geometries as alternative resistive switching matrices are reported. The possible resistive switching nature of the novel triple matrices is also discussed together with their electrical and structural properties. The ability to eliminate both an external resistor for efficient CRS operation and a metallic Pt middle electrode for further cost‐effective scalability will accelerate progress toward the realization of cross‐bar ReRAM in this framework.     

红外光谱法研究静磁场对大鼠脑组织的影响

电气工业的发展使得人们生存的环境中充满了各类频率的电磁污染,为了探讨静磁场可能产生的生物学效应及其发生机制,从实验上研究了0.17 T静磁场曝露作用30天后对于大鼠脑组织红外光谱特征的影响,实验结果显示实验组1549 cm-1附近的酰胺Ⅱ带吸收峰有较为明显的红移现象,在1635 cm-1处为蛋白质酰胺Ⅰ带峰位置有较大的差异,另外,利用二阶导数谱分析了实验组与对照组在分子结构上存在的差异。这些变化可以反映脑组织在静磁场曝露作用前后组成成分的变化,说明傅里叶变换红外光谱方法是研究电磁场不同生物效应的发生机制的一种有效手段。     

Cure and reaction kinetics of an anhydride‐cured epoxy resin catalyzed by N‐benzylpyrazinium salts using near‐infrared spectroscopy

The cure behavior and the reaction kinetics of an anhydride‐cured epoxy resin catalyzed by cationic thermal latent initiator, N‐benzylpyrazinium salts, have been investigated by a near‐infrared (NIR) spectroscopy. The spectral changes are interpreted in terms of the mechanism of cure. NIR absorption bands are due to protons connected to carbon, nitrogen, and oxygen. In this work, the homogeneous model system involves a simple addition reaction mechanism leading to an exothermic reaction between epoxide and anhydride activated groups. A comprehensive account of the origin, location, and shifts during reaction of all major NIR absorption peaks in the spectral range from 4000 to 7100 cm^?1 is provided. The extent of reaction is calculated from NIR absorption band at 4530 cm^?1, which depends on epoxide concentration. The utility of NIR spectroscopy to study the kinetics of epoxy cure reaction has been established. Consequently, absorbencies in the NIR spectra suitable for quantitative studies of epoxy resin reaction kinetics have been identified.     

卤代液晶进展

综述了卤代液晶近年来的进展,讨论了卤原子引入液晶端基、侧向位置及中心桥键等位置对液晶相变行为和光电性能的影响;简要叙述了卤代液晶的应用等。     

A 0.25-μm, 600-MHz, 1.5-V, fully depleted SOI CMOS 64-bitmicroprocessor

A 0.25-μm, four-layer-metal, 1.5-V, 600-MHz, fully depleted (FD) silicon-on-insulator (SOI) CMOS 64-bit ALPHA1 microprocessor integrating 9.66 million transistors on a 209-mm² silicon die has been developed leveraging the existing bulk design. FD-SOI technology is used because it has better immunity for dynamic leakage current than partially depleted SOI in high speed dynamic circuits without body contact. C-V characteristics of metal-oxide-silicon-oxide-silicon with and without source-drain junctions are described to explain the behavior of FD-SOI transistor. Race, speed, and dynamic stability have been simulated to reassure the circuit operation. Key process features are shallow trench isolation, 4-nm gate oxide, 30-nm co-silicide, 46-nm silicon film, and 200-nm buried oxide. The FD-SOI microprocessor runs 30% faster than that of bulk, and it passes the reliability and system test     

Chemoenzymatic Synthesis of Glycosylated Macrolactam Analogues of the Macrolide Antibiotic YC‐17

YC‐17 is a 12‐membered ring macrolide antibiotic produced from Streptomyces venezuelae ATCC 15439 and is composed of the polyketide macrolactone 10‐deoxymethynolide appended with D ‐desosamine. In order to develop structurally diverse macrolactam analogues of YC‐17 with improved therapeutic potential, a combined approach involving chemical synthesis and engineered cell‐based biotransformation was employed. Eight new antibacterial macrolactam analogues of YC‐17 were generated by supplying a novel chemically synthesized macrolactam aglycone to S. venezuelae mutants harboring plasmids capable of synthesizing several unnatural sugars for subsequent glycosylation. Some YC‐17 macrolactam analogues were active against erythromycin‐resistant bacterial pathogens and displayed improved metabolic stability in vitro. The enhanced therapeutic potential demonstrated by these glycosylated macrolactam analogues reveals the unique potential of chemoenzymatic synthesis in antibiotic drug discovery and development.