Computational Investigation Identified Potential Chemical Scaffolds for Heparanase as Anticancer Therapeutics

Heparanase (Hpse) is an endo-β-D-glucuronidase capable of cleaving heparan sulfate side chains. Its upregulated expression is implicated in tumor growth, metastasis and angiogenesis, thus making it an attractive target in cancer therapeutics. Currently, a few small molecule inhibitors have been reported to inhibit Hpse, with promising oral administration and pharmacokinetic (PK) properties. In the present study, a ligand-based pharmacophore model was generated from a dataset of well-known active small molecule Hpse inhibitors which were observed to display favorable PK properties. The compounds from the InterBioScreen database of natural (69,034) and synthetic (195,469) molecules were first filtered for their drug-likeness and the pharmacophore model was used to screen the drug-like database. The compounds acquired from screening were subjected to molecular docking with Heparanase, where two molecules used in pharmacophore generation were used as reference. From the docking analysis, 33 compounds displayed higher docking scores than the reference and favorable interactions with the catalytic residues. Complex interactions were further evaluated by molecular dynamics simulations to assess their stability over a period of 50 ns. Furthermore, the binding free energies of the 33 compounds revealed 2 natural and 2 synthetic compounds, with better binding affinities than reference molecules, and were, therefore, deemed as hits. The hit compounds presented from this in silico investigation could act as potent Heparanase inhibitors and further serve as lead scaffolds to develop compounds targeting Heparanase upregulation in cancer.     

The Chemistry of DPPH· Free Radical and Congeners

Since the discovery in 1922 of 2,2-diphenyl-1-(2,4,6-trinitrophenyl) hydrazyl stable free radical (DPPH^·), the chemistry of such open-shell compounds has developed continuously, allowing for both theoretical and practical advances in the free radical chemistry area. This review presents the important, general and modern aspects of the chemistry of hydrazyl free radicals and the science behind it.     

Non-Halogenated-Solvent Processed and Additive-Free Tandem Organic Solar Cell with Efficiency Reaching 16.67%

Organic solar cells (OSCs) have recently reached a remarkably high efficiency and become a promising technology for commercial application. However, OSCs with top efficiency are mostly processed by halogenated solvents and with additives that are not environmentally friendly, which hinders large-scale manufacture. In this study, high-performance tandem OSCs, based on polymer donors and two small-molecule acceptors with different bandgaps, are fabricated by solution processing with non-halogenated solvents without additive. Importantly, the two active layers developed from non-halogenated solvents show better phase segregation and charge transport properties, leading to superior performance than halogenated ones. As a result, a tandem OSC with high efficiency of up to 16.67% is obtained, showing unique advantages in future massive production.     

Free energy of conformational change in a single chain of polyvinylidene fluoride using molecular simulations

Polyvinylidene fluoride (PVDF) has several crystal forms of which the α-form is nonpolar, while the β-form is polar and has the highest piezoelectric constant. α PVDF, when stretched, transforms into the β form, which has wide applications in sensors and actuators. Steered molecular dynamics simulations are used to study the transformation of a single chain of PVDF from a trans–gauche conformation to an all trans one. The Helmholtz free energy change (∆F) is estimated using Jarzynski's equality. The transformation starts at the chain ends followed by the transformation of the remaining chain. The free energy change for the transformation is found to be always positive, indicating that the TGTG' form has higher thermodynamic stability than the all trans form throughout the studied temperature range. With increasing temperature, free energy change for the transformation increases monotonically.     

凌庄子水厂保水堰流量系数试验

凌庄子水厂蓄水池进水口处有一保水堰,为非标准薄壁堰,不能使用已有堰流公式对其过流量进行准确计算。为了得出较为精确的过流流量,按照重力相似准则制作几何比尺为1∶5的模型进行试验研究。在已有自由出流公式的基础上,对自由出流流量系数进行修正并对淹没情况下流量变化过程进行研究。对该非标准堰自由出流流量系数的实测值与经验值进行分析比较,发现堰板槽降低了实际自由出流过流能力。淹没出流的流量系数主要与下游尾水位有关,试验中形成的淹没式堰流受实际堰型尺寸影响,下游尾水位和堰上水位近似相等,不完全适用已有淹没出流流量公式,通过试验给出了修正淹没系数随h/p的变化关系。结果表明利用堰前、堰后水位初步计算过流流量是可行的,可为该工程提供参考,也可为实际工程中非标准矩形堰的流量计算提供思路。     

Sulfur doped biocarbon obtained from Sargassum spp. for the oxygen reduction reaction

Sulfured doped carbon electrocatalysts is synthesized from the waste biomass Sargassum spp. Two doping procedures are examined to determine which is better for Oxygen Reduction Reaction (ORR); one by doping biocarbon obtained from the pyrolysis of the biomass and the second through a process of in situ doping in autoclave. The electrocatalyst are obtained from pyrolysis of the sample at 700 °C, which is finally characterized as a metal free electrocatalyst for the ORR. The electrocatalyst are characterized by BET surface area analysis, Raman spectroscopy, X-ray Photoelectron Spectroscopy (XPS) and the electrochemical characterization is determined in 0.1 M KOH. The sample SSKPT-1 exhibits a promising electrocatalytic activity with an onset potential of 0.896 V vs RHE and a current density of 5 mA cm^?2 (at 0.2 V vs. RHE) which could be partly attributed to its high BET surface area of 2755 m² g^?1.     

Reasonable construction of proton conducting channel via biomimetic caterpillar-like alumina fiber to improve the properties of its composite proton exchange membrane

In this paper, we prepare a novel biomimetic caterpillar-like alumina fiber with the characteristic of continuous alumina backbone and fine needle whiskers spine. Then the high-performance caterpillar-like alumina fiber composite proton exchange membrane (CAPEM) is obtained by introducing the amino modified biomimetic caterpillar-like alumina fiber into sulfonated polysulfone (SPSF) matrix, which successfully reasonable construction of the proton conducting channels in both vertical and horizontal orientation. The properties of CAPEM, including proton conductivity, methanol permeability, etc. Are systematically studied. The results show that the proton conductivity of CAPEM increases with rising the temperature, which reaches the maximum of 0.263 S/cm at 80 °C and 100% RH, respectively. The excellent proton conductivity of CAPEM is attributed to the long-range continuous proton conducting channel formed by the horizontal continuous alumina skeleton in the in-plane direction and the vertical overlapped fine needle whiskers spine in the through-plane direction. In addition, the interfacial compatibility between amino modified caterpillar-like alumina fiber and SPSF matrix is enhanced through the reasonable construction of proton conducting channels, which effectively inhibits the methanol permeation of the composite membrane with 4.18 × 10^?7 cm² s^?1 and improves the comprehensive performance of the CAPEM.     

Sorption kinetics in metal hydrides by leaky coating

The 3D geometry of a hydrogen absorbing metal grain (Pd) is mimicked by a membrane made of the metal with identical properties, which is sealed on one side with a hydrogen semi-impermeable surface (Cu). The hydrogen loss through the sealed membrane surface is negligible, i.e., the hydrogen uptake measurement is that of a bulk material (Sieverts measurement), but the surface desorbs sufficient hydrogen to be detected by a mass spectrometer. With this, two independent spatial and temporal kinetic properties are defined which allow the reconstruction of the time dependent hydrogen distribution inside the membrane. As proof of concept, the mechanism of hydride formation in Pd is analyzed, corroborating the formation and growth of incoherent interfaces during hydrogen sorption.     

Effects of Bacillus velezensis zk1 on the physiology and metabolism of peaches

Bacillus velezensis zk1 is the dominant bacterium that causing rot in peaches. However, the mechanisms through that this bacterium causes rot have not been elucidated. Here, we explored the mechanisms of peach decay caused by B. velezensis zk1. The invasion of B. velezensis zk1 in peaches resulted in an increase in glucose and arabinose contents in fruit tissues. Moreover, the relative conductivity of the fruit reached 84% after 4 days of culture with bacterial invasion. With the destruction of cells, the malondialdehyde content increased, whereas the vitamin C, dialdehyde, flavonoid and total phenol contents decreased. Polyphenol oxidase, superoxide dismutase, catalase, peroxidase, ascorbate peroxidase and ammonia lyase activities also decreased. Overall, these findings demonstrated that B. velezensis zk1 infection damaged peach chloroplasts, mitochondria, respiratory chain activity and related free radical scavenging enzyme systems, thereby disrupting the normal physiological metabolism of peaches and causing rot.