桔梗多糖的制备工艺及生物活性研究进展

桔梗为桔梗科多年生植物[Platycodon grandiflorum (Jacq.) A.DC.]的根,具有悠久的食用和药用历史,是药食同源大宗品种之一,具有重要研究价值。桔梗根鲜品在中国东北和华北地区常被腌制为咸菜,市场需求量大,其干燥根则在中医临床常用于治疗咳嗽痰多,胸闷不畅,咽痛音哑,肺痈吐脓等病症。现有研究表明,桔梗中含有丰富的功能性多糖,在免疫调节、抗炎、止咳等生物活性方面发挥着至关重要的作用,具有重要的研究和开发前景。然而,当前国内外主要针对其结构与生物活性进行研究,尚无关于桔梗多糖的系统文献综述。该文通过梳理国内外有关桔梗多糖提取、分离纯化以及生物活性等方面的研究文献,对桔梗多糖的最新研究进展进行了系统归纳和总结,为日后桔梗多糖类成分的研究和深度开发利用提供参考。     

Influence of oxygen flow rate on photocatalytic TiO2 films deposited by rf magnetron sputtering

Titanium dioxide (TiO₂) thin films having anatase (1 0 1) crystal structure were prepared on non-alkali glass substrates by rf (13.56 MHz) magnetron sputtering using a TiO₂ ceramic target under various oxygen partial pressures. At a fixed substrate temperature of 400 °C and total gas pressure of 1 Pa after 3 h deposition. Effects of oxygen partial pressure on the structural, surface morphology, and photocatalytic activities of the TiO₂ thin films were investigated. We performed both photoinduced decomposition of methylene blue (MB) and photoinduced hydrophilicity under UV light illumination. The XRD patterns exhibited a broad-hump shape indicating the amorphous structure of TiO₂ thin films. The results showed that when the [O₂/(Ar + O₂)] flow rate increased to 50%, the photoinduced decomposition of MB and photoinduced hydrophilicity were enhanced. The water contact angle after 9 min UV illumination was approximately 4.5°, and the methylene blue (MB) solution decomposition from 12 down to 3.34 μ mol/L for 240 min UV irradiation.     

Immersion characteristics of electrolytic calcium phosphate coated Ti in simulated physiological fluid

The electrolytic calcium phosphate coatings have been deposited on titanium at room temperature and presented several differences with respect to other documented reports. The present study aimed to investigate the immersion behaviors of the uncoated titanium, the hydroxyapatite (HA) coated and the dicalcium phosphate dihydrate (DCPD) coated in the simulated physiological fluid (Hank's solution) at 37°C for 1, 7, 14, and 30 days. For the evaluation in dissolution or precipitation, morphology, composition, and crystal structure, the specimens were characterized by weight variation, X-ray diffraction, scanning electron microscopy, and energy dispersive spectroscopy before and after immersion. The plate-like DCPD structure was not stable in Hank's solution. However, its dissolution revealed the enhancing effect on the precipitation of newly formed hydroxyapatite. The calcium deficient hydroxyapatite (CDHA) can be conducted directly by the HA as-coated or the HA500 (annealed at 500°C, Ca/P = 1.63), or indirectly by the DCPD coated (Ca/P = 1.58), but not by the HA700 (annealed at 700°C, Ca/P = 1.80). The newly formed granular hydroxyapatite showed the more crystallization than the as-coated. Besides, the annealing enhanced the crystallization of the as-coated hydroxyapatite. Generally, the electrolytic CaP coating including the DCPD coated, HA as-coated, HA500, and HA700 specimens played an important role on the precipitation of newly formed hydroxyapatite in Hank's solution, but the uncoated Ti did not.     

量子点标记荧光免疫试纸条可视化检测肉品中志贺氏菌研究

志贺氏菌是一类具有强传染性和危害严重的革兰阴性食源性致病菌.该文利用自制的CdTe量子点偶联志贺氏菌单克隆抗体,将志贺氏菌单克隆抗体和羊抗鼠二抗分别喷涂硝酸纤维素膜,并分别作为试纸条检测线和质控线,研制一种可视化检测志贺氏菌的量子点免疫荧光试纸条.该试纸条对肉类实际样品的检测限为1×104 CFU/mL,单个样品检测时...     

Photo-Crosslinked Hyaluronic Acid/Carboxymethyl Cellulose Composite Hydrogel as a Dural Substitute to Prevent Post-Surgical Adhesion

A dural substitute is frequently used to repair dura mater during neurosurgical procedures. Although autologous or commercially available dural substitutes matched most of the requirements; difficulties during dural repair, including insufficient space for suturing, insufficient mechanical strength, easy tear and cerebrospinal fluid leakage, represent major challenges. To meet this need, a photo-crosslinked hydrogel was developed as a dural substitute/anti-adhesion barrier in this study, which can show sol-to-gel phase transition in situ upon short-time exposure to visible light. For this purpose, hyaluronic acid (HA) and carboxymethyl cellulose (CMC), materials used in abdominal surgery for anti-adhesion purposes, were reacted separately with glycidyl methacrylate to form hyaluronic acid methacrylate (HAMA) and carboxymethyl cellulose methacrylate (CMCMA). The HA/CMC (HC) hydrogels with different HA compositions could be prepared by photo-crosslinking HAMA and CMCMA with a 400 nm light source using lithium phenyl-2,4,6-trimethylbenzoylphosphinate as a photo-initiator. From studies of physico-chemical and biological properties of HC composite hydrogels, they are bio-compatible, bio-degradable and mechanically robust, to be suitable as a dural substitute. By drastically reducing attachment and penetration of adhesion-forming fibroblasts in vitro, the HC hydrogel can also act as an anti-adhesion barrier to prevent adhesion formation after dural repair. From in vivo study in rabbits, the HC hydrogel can repair dural defects as well as protect the dura from post-operative adhesion, endorsing the possible application of this hydrogel as a novel dural substitute.     

MPI下三维FDTD并行运算的分析与实现

基于Message-Passing Interface(MPI)的编程环境,以PML(Perfectly Matched Layer)为吸收边界条件,讨论了时域有限差分法FDTD的三维并行运算情况。通过一定的数值计算,定量地给出了MPI下FDTD并行算法中的网格数、进程数、分割方式三者之间的关系以及对计算效率的影响。     

Investigation of GaN-based light-emitting diodes using double photonic crystal patterns

GaN-based LEDs with photonic crystal (PhC) patterns on an n- and a p-GaN layer by nano-imprint lithography (NIL) are fabricated and investigated. At a driving current of 20 mA on Transistor Outline (TO)-can package, the light output power of the GaN-based LED with PhC patterns on an n- and a p-GaN layer is enhanced by a factor of 1.30, and the wall-plug efficiency is increased by 24%. In addition, the higher output power of the LED with PhC patterns on the n- and p-GaN layer is due to better crystal quality on n-GaN and higher scattering effect on p-GaN surface using PhC pattern structure.     

Growth and characterization of n-type InP/InGaAs quantum well infrared photodetectors for response at 8.93 µm

We present experimental results on the growth and characterization of n-type InGaAs/InP quantum-well intersubband photodetectors for use at 8.93 μm. High-quality InGaAs/InP multiple quantum wells were grown by gas source molecular beam expitaxy, and then characterized by double-crystal x-ray diffraction and cross-sectional transmission electron microscopy. Based upon the structural parameters determined by these methods, the photocurrent response spectra were simulated using a six-band effective bond-orbital model. The theoretical results are in excellent agreement with experimental data. Additional important device characteristics such as dark current, spectral response, and absolute responsivity are also presented.     

Alcohol‐Responsive,Hydrogen‐Bonded,Cholesteric Liquid‐Crystal Networks

Hydrogen‐bridged, cholesteric liquid‐crystal (CLC) polymer networks are adopted as an optical sensor material to distinguish between ethanol and methanol. Fast uptake of the alcohols is facilitated by an incorporated porosity created by breaking the hydrogen bridges and by a previously removed non‐reactive liquid‐crystal agent. The discrimination between the alcohols is based on the diversity in molecular affinity of ethanol and methanol with the hydrogen‐bridged CLC polymer networks. The CLC networks are molecular‐helix‐based, one‐dimensional bandgap materials with a discrete reflection band in the visible part of the spectrum that depends on the pitch of the molecular helix. The changes in positions of the reflection bands of the CLC network accurately discriminate between the alcohol types and provide information on their ratio in case they are blended.