引导性组织再生材料的研究进展

牙周病是人类最常见的口腔疾病之一,是成年人失牙的最主要原因。近年来,随着引导性组织再生(guided tissue regeneration,GTR)技术的建立和发展,GTR材料为治疗牙周病提供了一种有效的手段,同时也成为生物医用材料领域的研究热点。文章针对近些年来GTR材料的发展情况,综述了目前GTR材料的主要种类,阐述了GTR材料的作用原理,并根据植入性组织工程材料的要求,针对目前GTR材料存在的缺点提出了相应的改进方法,展望了GTR材料的发展趋势。     

口腔种植修复和常规修复在牙列缺损治疗中的效果观察

目的探讨牙列缺损采用口腔种植修复和常规修复临床对比情况。方法选取广东医学院附属厚街医院口腔科2014年5月至2015年5月收治,采用数字表抽取法随机分组,就常规修复(常规组,n=50)与种植修复(种植组,n=50)效果进行对比。结果观察组总有效率为92%,显著高于对照组70%(P0.05);观察组满意度各因子评分及总评分均高于对照组(P0.05)。结论牙列缺损采用口腔种植修复治疗,可显著提高临床效果,促患者咀嚼、发音等功能恢复,且美观度较理想,有较高推广应用价值。     

确定分子量的聚丙烯酸-β-羟乙酯的合成及其水溶液中水氢键缺损的拉曼光谱学研究

水溶性高分子经化学交联可得水凝胶 ,水凝胶也可由水溶性高分子经物理交联如部分结晶微区 ,疏水相互作用及缠绕交联得到 .线型水溶性高分子在水中以高浓度溶解时 ,高分子链之间相互搭迭缠绕也能形成物理“交联” .Ｋｉｔａｎｏ[1～ 4 ] 等研究了聚环氧乙烷、聚丙烯酸、聚丙烯酰胺和聚乙烯基吡咯烷酮等亲水性高分子水溶液中水分子间的氢键缺损情况 ,在重量浓度相同的情况下 ,随着分子量的增大 ,水分子间的氢键缺损加剧 .他们认为分子量大 ,高分子之间的缠绕就比较严重 ,在水溶液中就会形成许多小的微区 ,水分子在这些小微区中形成分子间氢键…     

抗生素和听力缺损

庆大霉素和其他氨基糖苷类抗生素能够损害听觉组织并使孕妇在妊娠期间因服药而导致胎儿出现不可逆性听力缺损。由洛杉矶的House Ear Institute的Federico Kalinec领导的小组最近查明了庆大霉素导致该缺损的原因。     

伤科黄水/聚乙烯醇静电纺丝纳米纤维创面敷料的制备及其性能北大核心CSCD

浸有中药伤科黄水的纱布处理伤口,药效短,需要反复用药,且易与伤口粘连,无法在吸收伤口分泌物的同时防止水分和电解质的流失等,限制了伤科黄水的应用和效果。针对上述问题,以超亲水高分子聚乙烯醇(PVA)为原料,通过高压静电纺丝,制备了一种担载伤科黄水的聚乙烯醇静电纺丝纳米纤维创面敷料。该创面敷料具有良好的机械性能、吸液能力和药物缓释功能,细胞毒性实验中,伤科黄水/PVA静电纺丝纳米纤维膜组的细胞存活率均在75%以上;其中,PVA质量分数为10%、黄水质量分数为2%的静电纺丝纤维膜,具有较高的拉伸强度和弹性模量,且具有良好的延展性和吸收渗出液能力,吸液能力可达自身重量的8倍以上。大鼠皮肤全层缺损修复实验中,该组创面敷料的愈合速度和创面修复效果明显优于伤科黄水原药组及其它低药物含量组。该伤科黄水/PVA静电纺丝纳米纤维膜可作为一种良好的创面覆盖物,吸收创口渗出、加速皮肤缺损修复,在拓宽院内制剂中药伤科黄水的应用形式和增强其使用效果等方面具有十分广阔的前景。     

Vanadium-based polyanionic compounds as cathode materials for sodium-ion batteries:Toward high-energy and high-power applications

Sodium ion batteries(SIBs)have been regarded as one of the alternatives to lithium ion batteries owing to their wide availability and significantly low cost of sodium sources.However,they face serious challenges of low energy&power density and short cycling lifespan owing to the heavy mass and large radius of Na⁺.Vanadium-based polyanionic compounds have advantageous characteristic of high operating voltage,high ionic conductivity and robust structural framework,which is conducive to their high energy&power density and long lifespan for SIBs.In this review,we will overview the latest V-based polyanionic compounds,along with the respective characteristic from the intrinsic crystal structure to performance presentation and improvement for SIBs.One of the most important aspect is to discover the essential problems existed in the present V-based polyanionic compounds for high-energy&power applications,and point out most suitable solutions from the crystal structure modulation,interface tailoring and electrode configuration design.Moreover,some scientific issues of V-based polyanionic compounds shall be also proposed and related future direction shall be provided.We believe that this review can serve as a motivation for further development of novel V-based polyanionic compounds and drive them toward high energy&power applications in the near future.     

Total synthesis of TRADD death domain with arginine N-GlcNAcylation by hydrazide-based native chemical ligation

TNFR1-associated death domain protein(TRADD)with arginine N-GlcNAcylation is a novel and structurally unique posttranslational modification(PTM)glycoprotein that blocks the formation of death-inducing signaling complex(DISC),orchestrating host nuclear factorκB(NF-κB)signaling in entero-pathogenic Escherichia coli(EPEC)-infected cells.This particular glycosylated modification plays an extremely vital role for the effective colonization and pathogenesis of pathogens in the gut.Herein we describe the total synthesis of TRADD death domain(residues 195-312)with arginine235 NGlcNAcylation(Arg-GIcNAc TRADD(195-312)).Two longish peptidyl fragments of the wild-type primary sequence were obtained by robust,microwave-assisted,highly efficient,solid-phase peptide synthesis(SPPS),the N-GlcNAcylated sector was built by total synthesis and attached specifically to resinbound peptide with an unprotected ornithine residue via silver-promoted on-resin guanidinylation,ArgGlcNAc TRADD(195-312)was constructed by hydrazide-based native chemical ligation(NCL).The facile synthetic strategy is expected to be generally applicable for the rapid synthesis of other proteins with Arg-GIcNAc modification and to pave the way for the related chemically biological study.     

Steam activation of Fe-N-C catalyst for advanced power performance of alkaline hydrazine fuel cells

Alkaline hydrazine liquid fuel cells(AHFC) have been highlighted in terms of high power performance with non-precious metal catalysts.Although Fe-N-C is a promising non-Pt electrocatalyst for oxygen reduction reaction(ORR),the surface density of the active site is very low and the catalyst layer should be thick to acquire the necessary number of catalytic active sites.With this thick catalyst layer,it is important to have an optimum pore structure for effective reactant conveyance to active sites and an interface structure for faster charge transfer.Herein,we prepare a Fe-N-C catalyst with magnetite particles and hierarchical pore structure by steam activation.The steam activation process significantly improves the power performance of the AHFC as indicated by the lower IR and activation voltage losses.Based on a systematic characterization,we found that hierarchical pore structures improve the catalyst utilization efficiency of the AHFCs,and magnetite nanoparticles act as surface modifiers to reduce the interracial resistance between the electrode and the ion-exchange membrane.     

Combined QSAR/QSPR,Molecular Docking,and Molecular Dynamics Study of Environmentally Friendly PBDEs with Improved Insulating Properties

To improve the insulating properties of polybrominated diphenyl ethers(PBDEs), we studied the molecular structures and energy gap(Eg) values of 209 PBDEs using a three-dimensional quantitative structure-activity relationship(3D-QSAR) model, molecular docking, and molecular dynamics. We also analyzed the interaction mechanisms of PBDEs using a 2D-QSAR model, molecular substitution characteristics, and molecular docking. The 3D-QSAR model showed that the 2-, 4-, 5-, and 6-positions significantly influenced the PBDE insulating properties. Using BDE-34 as a template molecule, we designed six derivatives with 0.47%-28.44% higher insulation tlian BDE-34. Compared with BDE-34, the stability and flame retardancy of the above six derivatives were not adversely affected. These derivatives, except for 2,6-cyanomethyl-BDE, 2-cyanomethyl-BDE, and 2-aniinomethyl-BDE, were more toxic and biodegradable than BDE-34, but showed weaker bioaccumulation and migration abilities than BDE-34. Mechanism analysis showed that the highest occupied orbital energy, the most negative charge, and the dipole moment were the main quantitative parameters that aflected the PBDE insulating properties. PBDE insulation gradually decreased as the number of Br atoms increased. The level of similarity between the substitution patterns on the two benzene rings was significantly correlated with PBDE insulation, with hydrophobic groups having a more significant efiect on PBDE insulation.     

Copolymers of tetrafluoroethene with chlorotrifluoroethene and with bromotrifluoroethene

Tetrafluoroethene (TFE)–chlorotrifluoroethene (CTFE) and TFE–bromotrifluoroethene (BTFE) copolymers have been synthesized by solution copolymerization over the entire range of comonomer composition. Crystallinity data are reported and first- and second-order transitions have been investigated by DSC. Glass transition temperatures of TFE-CTFE copolymers vary in a nonlinear fashion in the range defined by the homopolymers conforming best to the Johnston equation; the behavior in the TFE-BTFE system is more linear. Whereas TFE-BTFE copolymers show a steep decrease of melting temperature at higher BTFE content, due to the amorphous character of the polymers, more regular behavior was found for TFE-CTFE copolymers. Enthalpies of fusion are also reported. The results are discussed in relation to copolymer composition and structure and are compared with data on tetrafluoroethene–hexafluoropropene (FEP) fluorocarbon resins.     

Enthalphy of mixing of bromobenzene with n-alkanes,with cyclohexane,and with benzene

A dynamic flow microcalorimeter of the Picker design was used to measure enthalpies of mixing at 298.15 K and atmospheric pressure of the six binary systems bromobenzene + n-hexane, + n-heptane, + n-nonane, + n-tetradecane, + cyclohexane, and + benzene. Within the homologous series of n-alkane systems, the interaction parameter, h₁₂, calculated from rigid-lattice group contribution theory, decreases weakly with increasing chain length of the alkane. This behavior is quite analogous to that observed with chloro-derivatives of benzene + n-alkane.     

Reactions of amines with a dimer of hexafluoropropene and with a perfluorovinyl sulfide prepared with hexafluoropropene

Some reactions of amines with a perfluorovinylsulfide, (CF₃)₂CFSC(CF₃)CFCF(CF₃)₂, prepared from hexafluoropropene (HFP) and sulfur [1] are compared to reactions of the same amines with the thermodynamic dimer of HFP, (CF₃)₂CCFCF₂CF₃. Many new ketenimines, eneamines, amidines, nitriles, and quinoline derivatives are reported.     

Treatment of Wool with Laccase and Dyeing with Madder

This research has explored the effect of laccase (Denilite ІІ S) on the physical properties of the wool fabric and confirms the anti-felting of wool. In the experiment, laccase was applied to a wool fabric and different characteristics including weight loss, strength, alkali solubility, felting shrinkage, water drop absorption, and dye ability with madder were studied. The surface morphology of the wool fabrics was also observed by scanning electron microscope. The results indicated that the wool fabric treated with laccase has a higher water drop absorption, lower felting shrinkage, and lower values of a ^* and b ^*. Treatment of a wool fabric with 10% or lower percentage of laccase reduced the fabric weight but increased the tensile strength. However, using higher concentration of laccase reduced fabric weight and tensile strength. The dyeing of laccase pre-treated wool fabric with madder indicated a lower lightness.     

High-temperature reactions of trichloroethylene with toluene and with methanol

Conclusions The reactions of trichloroethylene with toluene and with methanol, conducted 560–570°, leads to the formation of a mixture of the isomers R-CH=CCl₂ and cis- and trans-R-CCl=CHCl (R=CH₂C₆H₅ and CH₂OH).Translated from Izvestiya Akademii Nauk SSSR. Seriya Khimicheskaya, No. 12, pp. 2777–2778, December, 1967.We thank E. D. Lubuzh and A. V. Kessenikh for determining and interpreting the IR and NMR spectra.