Structural features of an acidic polysaccharide with the potential of promoting osteoblast differentiation from Lycium ruthenicum Murr.

Abstract

The enhanced osteoblast differentiation is beneficial to the prevention of osteoporosis. In this study, a homogeneous polysaccharide (LRP-S2A) with the potential of promoting osteoblast differentiation was obtained from the fruits of Lycium ruthenicum, a traditional herb for treatment of postmenopausal metabolic disorders. Structural identification indicated that LRP-S2A, with a relative molecular weight of 2.65 × 10⁶ Da and an uronic acid content of 41.8%, contained Rha, Ara, Gal, Glc and GlcA in a molar ratio of 1.00 : 2.07 : 0.57 : 2.59 : 4.33 and was composed of a backbone consisting of 6-O-Me-α-(1→4)-D-GlcpA, 2-O-acetyl-α-(1→4)-D-Glcp, α-(1→2,4)-L-Rhap, β-(1→3)-D-Galp andα-(1→3,5)-L-Araf, and some branches consisting of 6-O-Me-α-(1→4)-D-GlcpA and terminal α-L-Araf. These results suggested that LRP-S2A with the potential of promoting osteoblast differentiation was a new acidic polysaccharide.     

Flavonoid compounds and antibacterial mechanisms of different parts of white guava (Psidium guajava L. cv. Pearl)

Abstract

The flavonoid compositions, extracted from leaves, peel and flesh of white guava (Psidium guajava L. cv. Pearl), were identified and quantified by UPLC-ESI-QTOF-MS, HPLC-ESI-MS/MS and HPLC. The main components of three extracts all were quercetin-glycosides, but the proportion and content of quercetin-hexoside and quercetin-pentoside in each extract were different. Based on the measurements of MIC, MBC value and time killing curve, it emerged that 3 flavonoid extracts of white guava had good antibacterial effects on four pathogenic bacteria. White guava leaves flavonoids (WGLF) concentrations of 5.00?mg/mL and 0.625?mg/mL could change the micro-morphology of Escherichia coli and Staphylococcus aureus. It suggested that the antibacterial mechanism of WGLF on gram-positive and gram-negative bacteria was to destroy the structure and function of the cell membrane. It is indicated that the flavonoid extracts from white guava is a potential natural antimicrobial agent.     

Portable capillary liquid chromatography for pharmaceutical and illicit drug analysis

A newly developed portable capillary liquid chromatograph was investigated for the separation of various pharmaceutical and illicit drug compounds. The system consists of two high‐pressure syringe pumps capable of delivering capillary‐scale flow rates at pressures up to 10 000 psi. Capillary liquid chromatography columns packed with sub‐2 μm particles are housed in cartridges that can be inserted into the system and easily connected through high‐pressure fluidic contact points by simply applying a specific, predetermined torque rather than using standard fittings and less precise sealing protocols. Several over‐the‐counter analgesic drug separations are demonstrated, along with a simple online measurement of tablet dissolution. Twenty illicit drug compounds were also separated across six targeted drug panels. The results described in this study demonstrate the capability of this compact liquid chromatography instrument to address several important drug‐related applications while simplifying system operation, and greatly reducing solvent usage and waste generation essential for onsite analysis.     

Predictable site-selective radical fluorination of tertiary ethers

In this communication,we disclose the first example of metal-free and site-selective radical fluorination of readily available tertiary alkyl ethers,enabled by synergistic photocatalysis and organocatalysis.This catalytic combination allows for exclusive fluorination of tertiary C–O bonds under mild conditions even in the presence of competing reaction sites.The excellent functional group tolerance affords valuable access to sterically hindered alkyl fluorides through late-stage modification of complex molecules.The successful use of tertiary alkyl ethers in radical fluorination enhances the structural diversity of aliphatic fluorides that can be derived from naturally abundant alcohols.     

超微血管成像和超声造影对乳腺癌病灶内微血流及超微血管的评价及其联合诊断价值

本文探讨了超微血管成像(SMI)和超声造影(CEUS)对乳腺癌病灶内微血流及超微血管的评价,及其联合检查对乳腺癌的诊断价值。选取2017年6月~2019年3月我院收治的经手术病理证实的乳腺癌患者106例(106个肿块)作为研究对象,所有患者术前均完成彩色多普勒血流显像(CDFI)、CEUS及SMI检查。比较SMI、CEUS对乳腺癌的诊断准确率及对病灶内血流信号、穿支血管的显示情况。结果显示,106例乳腺癌(106个肿块)中,SMI和CEUS对乳腺癌的诊断准确率分别为79.25%、83.96%,两者比较差异无统计学意义(P>0.05);SMI联合CEUS检查对乳腺癌的诊断准确率为96.23%,明显高于单一SMI或CEUS的诊断准确率(P<0.05)。在血流信号显示上,SMI检出不丰富血流信号、丰富血流信号分别为64个、42个;CEUS表现为低增强64个、等增强及高增强为42个;SMI和CEUS评价乳腺癌病灶内微血管及血流供应情况具有较好的一致性(P<0.05)。在穿支血管显示上,SMI检出44个、CDFI检出34个,SMI能够清晰检出CDFI不能检出的穿支血管10个。表明SMI和CEUS诊断乳腺癌病灶内微血管及血流供应情况具有较好的一致性,对乳腺癌均有较高的诊断价值,二者联合检查有助于提高乳腺癌的诊断准确率。     

General Approach to Single and Hybrid Metal Oxide Fiber Structures for High‐Performance Lithium‐Ion Batteries

Owing to the high specific capacity and energy density, metal oxides have become very promising electrodes for lithium‐ion batteries (LIBs). However, poor electrical conductivity accompanied with inferior cycling stability resulting from large volume changes are the main obstacles to achieve a high reversible capacity and stable cyclability. Herein, a facile and general approach to fabricate SnO₂, Fe₂O₃ and Fe₂O₃/SnO₂ fibers is proposed. The appealing structural features are favorable for offering a shortened lithium‐ion diffusion length, easy access for the electrolyte and reduced volume variation when used as anodes in LIBs. As a consequence, both single and hybrid oxides show satisfactory reversible capacities (1206 mAh g^?1 for Fe₂O₃ and 1481 mAh g^?1 for Fe₂O₃/SnO₂ after 200 cycles at 200 mA g^?1) and long lifespans.     

Reductive Aromatization of Quinols with B2pin2 as Deoxidizing Agent

We have demonstrated B₂pin₂ as superior deoxidizing agent for the reductive deoxygenation of quinol derivatives under basic conditions. A wide range of highly functionalized phenols were obtained in good yields including a complex drug molecule, which revealed the high functional group tolerance of this protocol.     

Beyond Perovskite Solar Cells: Tellurium Iodide as a Promising Light‐Absorbing Material for Solution‐Processed Photovoltaic Application

Searching new light‐absorbing materials to replace toxic lead halide in solar cells is very important and highly desirable. In this research, we firstly demonstrated that tellurium iodide (TeI₄) could be used as a light‐absorbing material in solar cells due to its suitable optical band gap and the active lone‐pair electron orbital in Te⁴⁺. The best power conversion efficiency (PCE=3.56%) was achieved with a concentration of 0.9 M TeI₄ in DMF:DMSO (4 : 1, v,v) without any heat treatment or antisolvent dripping. Our study indicates the promising potential of TeI₄ for photovoltaic and optoelectronic applications.     

$$\pmb {H_\infty }$$ H ∞ fusion estimation of time-delayed nonlinear systems with energy constraints: the finite-horizon case

Nonlinear Dynamics - The fusion estimation issue of sensor networks is investigated for nonlinear time-varying systems with energy constraints, time delays as well as packet loss. For the addressed...