Synthesis and Stability of Hydrogen Storage Material Aluminum Hydride

Aluminum hydride (AlH₃) is a binary metal hydride with a mass hydrogen density of more than 10% and bulk hydrogen density of 148 kgH2/m3. Pure aluminum hydride can easily release hydrogen when heated. Due to the high hydrogen density and low decomposition temperature, aluminum hydride has become one of the most promising hydrogen storage media for wide applications, including fuel cell, reducing agents, and rocket fuel additive. Compared with aluminum powder, AlH₃ has a higher energy density, which can significantly reduce the ignition temperature and produce H₂ fuel in the combustion process, thus reducing the relative mass of combustion products. In this paper, the research progress about the structure, synthesis, and stability of aluminum hydride in recent decades is reviewed. We also put forward the challenges for application of AlH₃ and outlook the possible opportunity for AlH₃ in the future.     

天津蓟县山区药用植物根际及自然土壤无机元素含量测定

[目的] 通过对天津蓟县山区8个代表区域的土壤以及常用重点药材根际土壤中无机元素[铁、锰、铜、锌、钾、钙、镁、铅、镉(Fe、Mn、Cu、Zn、K、Ca、Mg、Pb、Cd)]的含量测定,分析与评价土壤背景质量,为天津野生中药扩大种植奠定基础。[方法] 电热板湿法消解,火焰原子吸收光谱法测定Fe、Mn、Cu、Zn、K、Ca、Mg的含量,石墨炉原子吸收光谱法测定Pb、Cd的含量。[结果] 8个区域自然土壤样品中大量元素Fe、K、Ca、Mg的含量较多,Cu、Zn、Pb的含量水平相当。重金属元素Cu、Zn、Pb的含量均未超出标准,1个区域中Cd的含量稍有超标,但尚未对生态环境造成影响。药用植物根际土壤无机元素水平与蓟县山区自然土壤相当。[结论] 天津蓟县土壤无机元素含量适中,均达到自然背景水平,土壤整体质量较优。     

Impaired degradation and aberrant phagocytosis of necrotic cell debris in the peripheral blood of patients with primary Sjögren's syndrome

Aberrant removal of necrotic debris is considered a feature with inflammatory consequences in SLE. Herein, primary Sjögren's syndrome (SS) patients were investigated for the first time for the capacity of their sera to degrade secondary necrotic cell remnants (SNEC) and DNA (endonuclease DNase1 activity), as well as for uptake of SNEC by blood-borne phagocytes. For comparison, specimens from unselected SLE and RA patients and from healthy blood donors (HBD) were also studied. Compared to HBD, the sera from SS and SLE patients studied (but not RA) were found to exhibit significantly impaired capacity for degradation of SNEC (both for p = 0.007) and deficient DNase1 activity (both for p < 0.0001). The deficient DNase1 activity in SS and SLE sera did not owe to decreased DNase1 protein levels. It correlated inversely with increased serum levels of circulating nucleosomes and cell-free DNA (p < 0.0001), as well as with the disease activity indices of SS (r = −0.445, p = 0.0001) and SLE (r = −0.500, p = 0.013). In ex-vivo whole blood analyses, SS and SLE patients (but not RA) also manifested significantly increased SNEC-phagocytosis by monocytes and granulocytes (all for p < 0.0001) that also correlated with disease severity indices of SS (p = 0.001) and SLE (p = 0.01). In various cross-admixture experiments, such aberration was found to reside in the hyperfunctional activity of phagocytes, the impaired degrading activity of serum DNase1 and the SNEC-binding capacity of serum IgG of SS and SLE patients. The sera of SS and SLE patients (but not of RA) induced significant SNEC-phagocytosis by healthy monocytes that correlated inversely with the DNase1 activity (r = −0.634, p < 0.0001) of these sera. In line with this, the inhibition of DNase1 in HBD sera by G-actin was found to lead to significantly diminished SNEC degradation and increased SNEC uptake by healthy phagocytes (p = 0.0009), supporting the important physiologic role of serum DNase1 in the prevention of SNEC-phagocytosis. Purified serum IgG preparations from SS and SLE patients manifested increased binding to SNEC and were able to enhance significantly the engulfment of SNEC by healthy phagocytes both directly (under serum-free conditions, p ≤ 0.009) and via the prevention of physiologic degradation of SNEC by serum, most likely due to their “shielding” against endonuclease digestion (p = 0.0005). These data indicate that upon cell necrosis, the immune system of SS and SLE patients may be overly exposed to the necrotic debris, a fact that probably holds a key role in the pathogenesis of inflammatory and autoimmune reactions observed in these disorders.     

3D生物描绘孔结构可控钙磷硅基骨修复支架的生物力学性能

目的设计和制备新型钙磷硅基骨修复支架,研究其在不同外力作用下体外生物力学性能。方法以自固化磷酸钙骨水泥(calcium phosphate cement,CPC)、介孔硅酸钙(mesporous calcium silicate,MCS)为原料,通过3D生物描绘技术构建孔径分别为350、500μm的MCS/CPC复合支架。采用扫描电镜观察支架表面形貌;分别通过万能力学试验机和动态力学分析仪,考察具有不同孔道结构MCS/CPC支架的抗压力学性能和不同频率动态周期性载荷作用下的力学性能。结果通过3D生物描绘技术能够实现对钙磷硅基骨修复支架内部孔道结构的可控制备。孔径为350μm的MCS/CPC支架具有较高的抗压力学强度[(9.80±0.39)MPa]和抗压模量[(132.50±4.30)MPa];此外,载荷频率在1~100 Hz范围内,孔径为350μm的支架具有较高的储能模量。结论通过3D生物描绘技术制备的孔径为350μm的MCS/CPC复合支架不仅具有规则的连通孔道,还具有较高的抗压力学性能,能在动态载荷作用下保持结构稳定,适合作为一种新型的骨缺损修复材料。     

鼻内镜下眶下壁骨折修复方式及材料应用研究进展

眼眶骨折是指外力撞击眼部引起面中部多发骨折的外伤,按骨折性质大致可分为：爆裂性眶壁骨折、复合性眶壁骨折、复杂性眶壁骨折;按部位可分为眶下壁骨折、眶内侧壁骨折、眶下壁和眶内侧壁联合骨折,其中以眶下壁骨折最为常见。随着医学技术的进步与发展,手术修复是目前治疗眶下壁骨折最理想的方法,利用鼻内镜联合传统入路或直接经鼻腔入路手术具有可直视眶壁骨折的部位、直接评估伤情及制定手术方案等优势。本文针对眶下壁骨折的诊断、辅助检查、手术指征、鼻内镜修复眼眶骨折的手术术式、术式的优点和缺点及各种修复材料的特点等内容作一综述。     

Heat-assisted slurry sampling GFAAS method for determination of lead in food standard reference materials

A valid method based on heat-assisted slurry sampling graphic furnace atomic absorption spectrometry (HASS-GFAAS) was developed for the accurate determination of trace Pb in food standard reference materials (SRMs). The HASS technique significantly improved Pb recovery and precision compared to conventional slurry sampling techniques. The optimized HASS procedure was performed as follows: first, the sample (particle size ≤ 150 μm) was diluted with 0.05% (v/v) Triton X-100 containing 2% HNO₃ and 1% H₂O₂ followed by heating for 20 min at 120 °C on a heating block. Next, the obtained slurry was sonicated in an autosampler cup, and finally, the slurry was introduced into a graphite tube and analyzed by the GFAAS with a Pb electrodeless discharge lamp (EDL). Calibration with aqueous standard solutions was used for Pb determination in food samples. The characteristic mass and limit of detection for Pb based on the integrated absorbance for a 2% (m/v) sample were 12 ± 0.6 pg and 0.003 mg kg⁻¹, respectively. The accuracy (95.1–102% recovery) and good precision (0.1–3.6%) of this procedure are illustrated by the results obtained for the 12 food reference materials. The proposed method is suitable for determination of trace Pb in solid food samples.     

医院物资采购全程监督的实践

医院物资点多面广,专业性强,采购活动中涉及各个环节。文章按照医院物资采购的常规流程,对采购活动中各个环节的作用进行了分析,阐述了医院物资采购全程监督的实施要点。     

环孢素A软胶囊囊材的处方优化

以软胶囊内容物中乙醇和1,2-丙二醇含量和环孢素A溶出率为指标,采用正交设计优化软胶囊囊材处方,通过稳定性考察结果优化制备工艺.结果表明,在囊材处方中加入高级多元醇,并在环境相对湿度25％、采用缓慢干燥工艺使胶皮水分在40 h内控制在8％,所制备的软胶囊较稳定.与市售环孢素A软胶囊相比,本品内容物中乙醇的迁移量减少,环孢素A的体外溶出行为相似.药动学研究表明,自制软胶囊与市售软胶囊在Beagle犬体内生物等效.     

口腔材料固化过程检测仪器的设计开发与实现

口腔材料在固化过程中温度会发生变化,通过检测材料的温度变化可以实时跟踪固化过程。本文依据相关口腔材料检测标准,构建了一个新型的自动化检测系统,检测口腔材料工作时间、固化时间。经过初步的试验结果表明,该检测系统能有效采集口腔材料固化过程中温度信号,跟踪温度变化,连续检测固化过程,绘制温度曲线,并能够依据标准要求自动处理曲线,从而得到口腔材料固化过程中高精度的工作时间、固化时间。