大肠杆菌代谢物组测定中抽提方法的比较分析

代谢物组学作为一种重要的功能基因组学工具,已经在微生物性状改良等方面得到了应用。实施代谢物组学研究需要定性和定量分析细胞内的全部代谢物。所以,必须有一种能够提供良好的重复性和相对抽提效率较高的细胞内代谢物抽提方法。本研究以特定厌氧条件下培养的大肠杆菌为研究对象,以电喷雾质谱直接进样测定为评价标准,比较并分析了冰甲醇、热乙醇和碱抽提3种抽提方法。结果显示,冰甲醇抽提的样品在电喷雾质谱实验中表现出良好的重复性和最高的峰强度,并能够同时检测到超过20种不同的胞内代谢物。     

Alkyl-Chain-Regulated Charge Transfer in Fluorescent Inorganic CsPbBr3 Perovskite Solar Cells

Improved charge extraction and wide spectral absorption promote power conversion efficiency of perovskite solar cells (PSCs). The state-of-the-art carbon-based CsPbBr₃ PSCs have an inferior power output capacity because of the large optical band gap of the perovskite film and the high energy barrier at perovskite/carbon interface. Herein, we use alkyl-chain regulated quantum dots as hole-conductors to reduce charge recombination. By precisely controlling alkyl-chain length of ligands, a balance between the surface dipole induced charge coulomb repulsive force and quantum tunneling distance is achieved to maximize charge extraction. A fluorescent carbon electrode is used as a cathode to harvest the unabsorbed incident light and to emit fluorescent light at 516 nm for re-absorption by the perovskite film. The optimized PSC free of encapsulation achieves a maximum power conversion efficiency up to 10.85 % with nearly unchanged photovoltaic performances under 80 %RH, 80 °C, or light irradiation in air.     

3-甲基邻苯二酚/糠胺型聚苯并噁嗪的制备与性能

通过分子设计合成了含有酚羟基的3-甲基邻苯二酚/糠胺型苯并噁嗪(M-f). 通过差示扫描量热法(DSC)测得M-f的放热峰值温度(T_p)为172 ℃, 而间甲酚/糠胺型苯并噁嗪(MC-f)的T_p为244 ℃, 表明酚羟基的引入有利于降低苯并噁嗪的开环固化温度. 通过非等温DSC法研究2种苯并噁嗪单体的固化动力学, Kissinger法和Ozawa法的计算结果均表明M-f的表观活化能低于MC-f. 此外, 通过拉伸剪切强度测试考察了聚苯并噁嗪对于金属基材的黏附性能, M-f聚合物对于铝和低碳钢基材的拉伸剪切强度分别为2.53 MPa和3.09 MPa, 均高于MC-f聚合物.     

Regularity of solutions to the perturbed conservation laws

A kind of regularity for the mild solution of perturbed conservation laws is proposed. This regularity is described in term of variations measured in the L¹-norm. A dissipativity condition from the semigroup approach is used to show that the mild solution stays within a class of bounded variation in this sense of regularity. This shows that this class of functions is an invariant of the semigroup. The same analysis carries over to the periodic problem. The class of boundedL¹-variation functions used here can be normed to give a Banach space structure. It also has an analogue with the space of Lipschitz functions     

Comprehensive bioinformatics study reveals targets and molecular mechanism of hesperetin in overcoming breast cancer chemoresistance

Molecular Diversity - The effectiveness of chemotherapy in breast cancer treatment can be increased using a combinatorial agent. Hesperetin has been reported to increase the sensitivity of...     

Whole column fluorescence imaging on a microchip by using a programmed organic light emitting diode array as a spatial-scanning light source and a single photomultiplier tube as detector

A novel miniaturized, integrated whole-column imaging detection (WCID) system on a microchip is presented. In this system, a program controlled organic light emitting diode (OLED) array was used as a spatial-scanning light source, to achieve imaging by the time sequence of the excited fluorescence. By this mechanism, a photomultiplier tube (PMT) instead of a charge coupled detector (CCD) can be applied to the imaging. Unlike conventional systems, no lenses, fibers or any mechanical components are required either. The novel flat light source provides uniform excitation light without size limitations and outputs a stronger power by pulse driving. The scanning mode greatly reduced the power consumption of the light source, which is valuable for a portable system. Meanwhile, this novel simplified system has a broader linear range, higher sensitivity and higher efficiency in data collection. Isoelectric focusing of R-phycoerythrin (PE) and monitoring of the overall process with WCID were performed on this system. The limit of detection (LOD) was 38 ng mL(-1) or 3.2 pg at 85 nL per column injection of PE. The system provides a technique for WCID capillary isoelectric focusing (cIEF) on chip and can be used for throughput analysis.     

Syntheses,Crystal Structures,and Properties of Four Coordination Compounds with Sulfonate-Naphthol Ligand

Russian Journal of General Chemistry - Four coordination compounds, [Zn(ndsp)(bipy)2(H2O)]2·2H2O (1), Mn(ndsp)(bipy)2(H2O)·H2O (2), Ni(ndsp)(bipy)2(H2O) (3),...     

Grazing incidence impact of ions on an adatom-covered surface: Molecular-dynamics study of sputtering, surface-damage formation and ion-induced adatom mobility

Using molecular-dynamics simulation, we study the exemplary case of 5 keV Ar impact onto a Pt(1 1 1) surface at 83° incidence angle towards the surface normal. Under these conditions, on a flat terrace, the ions are specularly reflected, inducing neither damage nor sputtering of the surface. This situation changes drastically, if the surface is covered randomly with a coverage Θ of adatoms. For 0.1 < Θ < 0.5, average sputter yields and damage of up to a value of 5 and 9, respectively, are achieved. For coverages around Θ = 0.3-0.4, 50 adatoms are relocated on the average on the surface, affecting an area of around 1000 Å². This ion-induced mobility promotes adatom clustering, which typically leads to a rim-like structure around the ion impact point.     

Extracting the phase distribution of the electron wave packet ionized by an elliptically polarized laser pulse

We use an interferometic scheme to extract the phase distribution of the electron wave packet from above-threshold ionization in elliptically polarized laser fields. In this scheme, an electron wave packet released from a circularly polarized laser pulse acts as a reference wave and interferes with the electron wave packet ionized by a time-delayed counter-rotating elliptically polarized laser field. The generated vortex-shaped interference pattern in the photoelectron momentum distribution enables us to extract the phase distribution of the electron wave packet in the elliptically polarized laser pulse with high precision. By artificially screening the ionic potential at different ranges when solving the time-dependent Schördinger equation, we find that the angle-dependent phase distribution of the electron wave packet in the elliptically polarized laser field shows an obvious angular shift as compared to the strong-field approximation, whose value is the same as the attoclock shift. We also show that the amplitude of the angle-dependent phase distribution is sensitive to the ellipticity of the laser pulse, providing an alternative way to precisely calibrate the laser ellipticity in the attoclock measurement.     

On the comparison of the spaces

The notion of -variation and the space arise in the study of regularity properties of solutions to perturbed conservation laws. In this article we show that this notion is equivalent to variation in the regular sense, and therefore the space is the same as the space in the sense of Cesari-Tonelli. We also point out some connection between the space and the Favard classes for translation semigroups.