The Antibacterial Activity Mode of Action of Plantaricin YKX against Staphylococcus aureus

We aimed to evaluate the inhibitory effect and mechanism of plantaricin YKX on S. aureus. The mode of action of plantaricin YKX against the cells of S. aureus indicated that plantaricin YKX was able to cause the leakage of cellular content and damage the structure of the cell membranes. Additionally, plantaricin YKX was also able to inhibit the formation of S. aureus biofilms. As the concentration of plantaricin YKX reached 3/4 MIC, the percentage of biofilm formation inhibition was over 50%. Fluorescent dye labeling combined with fluorescence microscopy confirmed the results. Finally, the effect of plantaricin YKX on the AI-2/LuxS QS system was investigated. Molecular docking predicted that the binding energy of AI-2 and plantaricin YKX was −4.7 kcal/mol and the binding energy of bacteriocin and luxS protein was −183.701 kcal/mol. The expression of the luxS gene increased significantly after being cocultured with plantaricin YKX, suggesting that plantaricin YKX can affect the QS system of S. aureus.     

壳层厚度对骨架Fe@HZSM-5核壳催化剂费托合成催化性能的影响

在不同的水热合成时间下,以铁铝合金为铁源和铝源,四丙基氢氧化铵为分子筛的模板剂和抽提合金中的铝的碱,一步制得了以骨架铁为核、不同厚度的HZSM-5分子筛为壳的Raney Fe@HZSM-5催化剂.采用元素分析、氮物理吸附、X射线粉末衍射、氨脱附、扫描电子显微镜等手段,考察了水热时间对催化剂基本物化性质的影响.随着水热时...     

MAGNETOMECHANICAL BEHAVIORS OF GIANT MAGNETOSTRICTIVE MATERIALS

The Laves phase alloy Tb-Dy-Fe, commercially known as Terfenol-D, exhibits the giant room-temperature magnetostriction at moderate field strength of a few kOe due to its combination of high magnetostriction and low magnetocrystalline anisotropic energy. Thus, this pseudobinary rare earth iron compound has found quite a number of applications such as in magnetomechanical transducers, actuators and adaptive vibration control systems. The simultaneous measurements of magnetostriction and magnetization at various fixed compressive pre-stresses applied in the axial direction for Tb0.3Dy0.7Fe1.95 samples are presented. The results show that the magnetostriction increases with increasing compressive stress until it reaches 1742 ×10^6 under 25 MPa, so does the coercive magnetic field. And the hysteresis loop area for magnetization and magnetostriction also increases with the increment of applied compressive stresses. But the maximum magnetic susceptibility χ（dM/dH） is obtained under zero stress field and the strain derivative dλ/dH increases to the highest amplitude of 0.039×10^-6 A^-1m at a stress level of 5 MPa. In the strain versus magnetization intensity curve, the initial fiat stage mainly consisting of a 180° domain wall motion becomes shorter with increasing stress. It means more initial domains are driven to the transversal direction under the compressive stress before magnetization, which is consistent with the improvement of the magnetostriction.     

溶胶陈化对聚酰亚胺/二氧化硅杂化薄膜性能的影响

采用不同陈化时间的酸催化硅溶胶制备SiO2含量一定的聚酰亚胺/二氧化硅杂化薄膜,用FTIR-ATR、SEM、TMA等手段对其微相结构、热稳定性、力学性能进行了研究.结果表明:随着硅溶胶水解和聚合反应的进行,杂化薄膜中的SiO2颗粒由棒状长大为球体,并逐渐团聚、变形,薄膜的光学透明性降低,热膨胀系数逐渐减小,拉伸强度先增大后减小.当球形SiO2颗粒的直径小于1 μm且均匀分布在基体中时,薄膜综合性能最优.     

顺式氰戊菊酯与牛血清白蛋白相互作用的荧光光谱研究

用荧光光谱法研究了在生理pH值条件下杀虫剂顺式氰戊菊酯与牛血清白蛋白(BSA)的相互作用。结果表明:顺式氰戊菊酯对BSA的荧光有较强的猝灭作用,该猝灭属于静态猝灭。根据猝灭结果求得了不同温度下顺式氰戊菊酯与牛血清白蛋白作用的结合位点数、结合常数及反应热力学参数,并据此推测了它们之间主要的相互作用力为疏水作用力。还用同步荧光光谱法探讨了顺式氰戊菊酯对BSA构象的影响。     

JJG 1002-2005旋转黏度计计量检定规程存在的问题探讨

对JJG 1002-2005旋转黏度计计量检定规程存在的问题进行探讨,指出该规程不适合血液黏度计的检定,应重新制订血液黏度计计量检定规程或计量校准规范,以适应医学临床需要.     

Preparative Mass Spectrometry Using a Rotating-Wall Mass Analyzer

The design of functional interfaces is central to both fundamental and applied research in materials science and energy technology. We introduce a new, broadly applicable technique for the precisely controlled high-throughput preparation of well-defined interfaces containing polyatomic species ranging from small ions to nanocrystals and large protein complexes. The mass-dispersive deposition of ions onto surfaces is achieved using a rotating-wall mass analyzer, a compact device which enables the separation of ions using low voltages and has a theoretically unlimited mass range. We demonstrate an efficient deposition of singly charged Au₁₄₄(SC₄H₉)₆₀ ions (33.7 kDa), which opens up exciting opportunities for the structural characterization of nanocrystals and their assemblies using transmission electron microscopy. Our approach also enables the high-throughput deposition of mass-selected ions from multicomponent mixtures, which is of interest to the controlled preparation of surface gradients and rapid screening of molecules in mixtures for a specific property.     

A mechanically robust copper mesh with switchable wettability and antibacterial activity for selective oil–water separation

With the continuous improvement in living standards, the discharge of oily sewage in daily life and industry has gradually increased, causing considerable damage to the environment and also great inconvenience to people. Traditional treatment methods cannot meet the increasing demand for sewage treatment, so more efficient treatment methods need to be studied. Research on oil–water separation materials is gradually becoming intelligent, but most of these intelligent materials cannot solve the problem of bacterial growth on the surface, new antibacterial and hydrophobic materials need to be studied. Here, an inexpensive and simple method is presented to prepare an antibacterial copper mesh with pH-responsive wettability between hydrophilic and hydrophobic. First, a copper mesh with a rough surface was prepared by an oxidation method, and then the oxidized copper mesh was immersed in the prepared coating solution of stearate (SA)-TiO₂ to obtain a superhydrophobic copper mesh. Scanning electron microscopy analysis showed that the modified copper mesh changed from the original smooth surface to a rough surface covered with needle-like nano-oxide wires. The SA-TiO₂-coated copper mesh (STCM) has good separation efficiency (about 97%) and separation flux (about 1.1 × 10⁵ L·m⁻²·h⁻¹) for the immiscible oil–water mixture, the separation efficiency remained basically unchanged (about 97%) after 15 separation cycles, and the wettability of this can be changed by soaking in an alkaline solution at a specific pH (from 12 to 14). In addition, the prepared STCM showed good antibacterial properties against Staphylococcus aureus and Escherichia coli. This preparation strategy of STCM provides a low-cost and facile method for wastewater treatment in practical applications.     

Synthesis and Crystal Structure of 1-(3-Amino-4-Morpholino-1H-Indazole-1-Carbonyl)-N-(4-Methoxyphenyl)Cyclopropane-1-Carboxamide,a Molecule with Antiproliferative Activity

Crystallography Reports - Compound 1-(3-amino-4-morpholino-1H-indazole-1-carbonyl)-N-(4-methoxyphenyl)cyclopropane-1-carboxamide (C22H23N5O3, Mr = 870.96) was synthesized by condensation of...     

The Study on Potential Biomarker in Rat After Withdrawal of Cimaterol Using Untargeted Metabonomics

Chromatographia - The present study was performed to screen the potential biomarkers of cimaterol in rat, using an untargeted metabonomics approach. The liver and serum samples were analyzed by...