基于中国生物医学文献数据库的艾滋病文献计量分析

目的利用文献计量学的研究方法,揭示我国艾滋病研究现状。方法利用中国生物医学文献数据库(CBMDisc)检索中国1981-2011年发表的所有艾滋病文献,利用noteexpress软件处理数据,对发表年代、作者、机构、基金、发表期刊及主题分布进行分析。结果共检索到34 529篇文献,文献最早开始于1983年并逐年增多,早期文献以译文及综述为主。基金资助论文占总论文的比例逐年增加。艾滋病研究涉及的学科广泛,合作化趋势强。发文机构以疾病预防控制中心、综合性医院、高校为主。从主要主题词分析中,艾滋病研究主要围绕流行病、治疗以及实验室研究三大领域展开。结论我国艾滋病研究开始较早,艾滋病研究经历了一个萌芽、快速发展、成熟等3个阶段,现研究进入一个相对平稳的阶段。随着社会的不断发展,艾滋病研究在我国越来越受到重视,并已达到一个较高的水平。     

斑点免疫酶渗滤法快速检测甲型流感病毒的临床应用

目的 明确快速筛查甲型流感病毒的方法.方法 收集2009年11月至2010年3月就诊于广州医学院第一附属医院发热门诊及中医科门诊40例流感样患者的鼻咽分泌物进行病毒检测,男18例,女22例,年龄5～62岁,平均年龄(31.3±13.2)岁.以2009年9月卫生部颁布的qRT-PCR方法检出甲型流感病毒作为诊断标准,比较2种快速病原检测法——斑点免疫酶渗滤法(DIEFA)和胶体金免疫层析法(GICA)对甲型流感病毒的检出率,以确定敏感性好、特异性高的方法为甲型流感病毒快速筛查法.结果 40例标本中,qRT-PCR检出甲型流感病毒21例,阳性率为52.5％;DIEFA检出甲型流感病毒22例,检出率为55.0％;GICA检出甲型流感病毒12例,检出率为30.0％.与qRT-PCR比较,DIEFA的灵敏度、特异性和一致性分别是85.7％、78.9％和82.5％,而GICA的灵敏度、特异性和一致性分别是42.8％、84.2％和62.5％.DIEFA对甲型流感病毒检出的灵敏度明显优于GICA(P＜0.05).结论 DIEFA方法检测甲型流感病毒具有灵敏度高及特异性好的优势,适用于流感流行季节对甲型流感病毒的快速诊断和筛查.     

Electro–opto–mechano driven reversible multi-state memory devices based on photocurrent in Bi0.9Eu0.1FeO3/La0.67Sr0.33MnO3/PMN-PT heterostructures

A single device with extensive new functionality is highly attractive for the increasing demands for complex and multifunctional optoelectronics. Multi-field coupling has been drawing considerable attention because it leads to materials that can be simultaneously operated under several external stimuli (e.g. magnetic field, electric field, electric current, light, strain, etc.), which allows each unit to store multiple bits of information and thus enhance the memory density. In this work, we report an electro–opto–mechano-driven reversible multi-state memory device based on photocurrent in Bi_0.9Eu_0.1FeO₃ (BEFO)/La_0.67Sr_0.33MnO₃ (LSMO)/0.7Pb(Mg_1/3Nb_2/3)O₃-0.3PbTiO₃ (PMN-PT) heterostructures. It is found that the short-circuit current density (J_sc) can be switched by the variation of the potential barrier height and depletion region width at the Pt/BEFO interface modulated by light illumination, external strain, and ferroelectric polarization reversal. This work opens up pathways toward the emergence of novel device design features with dynamic control for developing high-performance electric–optical–mechanism integrated devices based on the BiFeO₃-based heterostructures.

The mutual interaction between polarization switching, light and piezoelectric strain.     

An ultra-sensitive T2-weighted MR contrast agent based on Gd3+ ion chelated Fe3O4 nanoparticles

An ultra-sensitive T₂-weighted MR imaging contrast agent was prepared based on Fe₃O₄ nanoparticles and Gd³⁺ ions (Fe₃O₄@Gd). Amino modified Fe₃O₄ nanoparticles were conjugated to diethylenetriamine pentaacetic acid, and finally coordinated with Gd³⁺ ions. The nanoparticles had a uniform morphology with a size of 100 nm and a Gd/Fe mass ratio of 1/110. The r₂ (transverse relaxivity) of the Fe₃O₄ nanoparticles increased from 131.89 mM⁻¹ s⁻¹ to 202.06 mM⁻¹ s⁻¹ after coordination with Gd³⁺ ions. MR measurements showed that the aqueous dispersion of Fe₃O₄@Gd nanoparticles had an obvious concentration-dependent negative contrast enhancement. Hepatoma cells were selected to test the cytotoxicity and MR imaging effect. The application of Fe₃O₄@Gd nanoparticles as contrast agents was also exploited in vivo for T₂-weighted MR imaging of rat livers. All the results showed the effectiveness of the nanoparticles in MR diagnosis.

An ultra-sensitive T₂-weighted MR imaging contrast agent was prepared based on Fe₃O₄ nanoparticles and Gd³⁺ ions (Fe₃O₄@Gd).     

Hydrolytic dehydrogenation of NH3BH3 catalyzed by ruthenium nanoparticles supported on magnesium–aluminum layered double-hydroxides

Ammonia borane (AB, NH₃BH₃) with extremely high hydrogen content (19.6 wt%) is considered to be one of the most promising chemical hydrides for storing hydrogen. According to the starting materials of AB and H₂O, a hydrogen capacity of 7.8 wt% is achieved for the AB hydrolytic dehydrogenation system with the presence of a highly efficient catalyst. In this work, ruthenium nanoparticles supported on magnesium–aluminum layered double hydroxides (Ru/MgAl-LDHs) were successfully synthesized via a simple method, i.e., chemical reduction. The effect of Mg/Al molar ratios in MgAl-LDHs on the catalytic performance for AB hydrolytic dehydrogenation was systematically investigated. Catalyzed by the as-synthesized Ru/Mg₁Al₁-LDHs catalyst, it took about 130 s at room temperature to complete the hydrolysis reaction of AB, which achieved a rate of hydrogen production of about 740 ml s⁻¹ g⁻¹. Furthermore, a relatively high activity (TOF = 137.1 mol_H2 mol_Ru⁻¹ min⁻¹), low activation energy (E_a = 30.8 kJ mol⁻¹) and fairly good recyclability of the Ru/Mg₁Al₁-LDHs catalyst in ten cycles were achieved toward AB hydrolysis for hydrogen generation. More importantly, the mechanism of AB hydrolysis catalyzed by Ru/MgAl-LDHs was simulated via density functional theory. The facile preparation and high catalytic performance of Ru/MgAl-LDHs make it an efficient catalyst for hydrolytic dehydrogenation of AB.

Ru/MgAl-LDHs catalyst was successfully prepared, which exhibited higher catalytic activity and lower activation energy toward the hydrolysis of ammonia borane for hydrogen production.     

Molecular simulations of gas transport in hydrogenated nitrile butadiene rubber and ethylene–propylene–diene rubber

Diffusion and sorption of five gases (H₂, N₂, O₂, CO₂, CH₄) in hydrogenated nitrile butadiene rubber (HNBR) and ethylene–propylene–diene rubber (EPDM) have been investigated by molecular dynamics (MD) and grand canonical Monte Carlo (GCMC) simulations. The diffusion coefficients of gas molecules in HNBR and EPDM are well correlated with the effective penetrant diameter except for CO₂. CO₂ shows a lower diffusion coefficient due to its linear shape. Additionally, the favorable interaction between CO₂ and HNBR is another factor for its lower diffusion coefficient in HNBR. HNBR shows lower diffusion coefficients than EPDM. This is because the polar –CN groups in HNBR chains increase interchain cohesion and result in tight intermolecular packing, low free volume and poor chain mobility, which decreases the diffusion coefficients of HNBR. The solubility coefficients of CH₄, O₂, N₂ and H₂ in HNBR are lower than those in EPDM, which is a result of the weak HNBR–penetrant interactions and low free volume of HNBR. However, the solubility coefficient of CO₂ in HNBR is higher than in EPDM. This is attributed to the strong interaction between CO₂ and HNBR. H₂, O₂, N₂ and CH₄ show lower permeability coefficients in HNBR than in EPDM, while CO₂ has higher permeability coefficients in HNBR. These molecular details provide critical information for the understanding of structures and gas transport between HNBR and EPDM.

Diffusion and sorption of five gases (H₂, N₂, O₂, CO₂, CH₄) in HNBR and EPDM were explored by MD and GCMC simulations.     

Two rare {M2(MoO4)2}n chain-containing molybdate-based metal–organic complexes with a bis-pyrazole-bis-amide ligand: fluorescent sensing and photocatalysis performance

By introducing a bis-pyrazole-bis-amide ligand, N,N′-bis(1H-pyrazole-4-carboxamide)-1,4-benzene (L), two molybdate-based metal–organic complexes containing {M₂(MoO₄)₂}_n (M = Co, Zn), [Co₂L₂(MoO₄)₂]·H₂O (1), [Zn₂L₂(MoO₄)₂]·H₂O (2), have been prepared under hydrothermal/solvothermal conditions. X-ray diffraction analyses reveal that both 1 and 2 are isostructural. An interesting structural feature is that a kind of {M₂(MoO₄)₂}_n chain could be found in 1 and 2, although different raw materials [Mo₇O₂₄]⁶⁻ and [PMo₁₂O₄₀]³⁻ anions were utilized. Then these chains are further linked by L ligands into a two dimensional (2D) structure. The title complexes represent the first examples containing {MoO₄} units and pyrazole-/or amide-derivative ligands. Complexes 1 and 2 exhibit distinct performances due to different metal centers, with 2 acting as a fluorescent sensor for Fe³⁺, MnO₄⁻, CrO₄²⁻ and Cr₂O₇²⁻, but 1 being a better photocatalyst towards degradation of cationic dyes methylene blue (MB) and neutral red (NR).

Two molybdate-based complexes containing {M₂(MoO₄)₂}_n (M = Co or Zn) chains were obtained, which demonstrated different properties: excellent photocatalytic degradation performance of cationic dyes for 1 and fluorescence sensing behavior for 2.     

Temperature controlled condensation of nitriles: efficient and convenient synthesis of β-enaminonitriles, 4-aminopyrimidines and 4-amidinopyrimidines in one system

A series of β-enaminonitriles, 4-aminopyrimidines and 4-amidinopyrimidines were synthesized by condensation of organonitriles in one system. A wide variety of compounds were obtained in good to excellent yields by simply controlling the reaction temperature. The base-induced transformation process is easy for production. The scope and versatility of the method have been successfully demonstrated with 72 examples. The flexible and diversified characteristics of nitriles were introduced based on electronic effect, steric effect, position of substituted groups and intermolecular hydrogen bonding. An updated reaction mechanism is proposed based on the study of the stoichiometric reaction conditions at variable temperature, and on the investigation of products with cis–trans configuration transformation.

A wide variety of β-enaminonitriles, 4-aminopyrimidines and 4-amidinopyrimidines were simply synthesized from organonitriles by controlling the reaction temperature.     

S-doped porous carbon anode with superior capacity for high-performance sodium storage

Heterogeneous carbon-based materials with high porosity are attracting increased attention for energy storage due to their enhanced capacity and rate performance. Herein, we report a sulfur-doped porous carbon material, which is achieved by spray-drying and subsequent sulfuration. The porous structure can provide vast diffusive tunnels for the fast access of electrolytes and sodium ions. Also, the S–C bond increases the electrical conductivity of the carbon frameworks and offers excessive reaction sites for sodium-ion storage. The elaborated carbon architecture enables a high capacity of 370 mA h g⁻¹ at 0.5 A g⁻¹ and provides an excellent rate performance for long-term cycling (197 mA h g⁻¹ at 2.0 A g⁻¹ for 650 cycles). Considering the scalable and facile spray-pyrolysis preparation route, this material is expected to serve as a low-cost and environmentally friendly anode for practical sodium-ion batteries.

A novel S-doped porous carbon material with superior sodium storage performance was obtained through spray-drying and subsequent sulfur doping treatment.     

C1–2 transarticular screws combined with C1 laminar hooks fixation: a modified posterior atlantoaxial fixation technique and outcome in 72 patients

Purpose

To retrospectively evaluate the outcome of C1–2 transarticular screws combined with C1 laminar hooks fixation.

Methods

All patients underwent atlantoaxial fixation during a 5-year period. The surgical technique and treatment procedures were intensively reviewed and clinical symptoms, neurological function and imaging appearance were retrospectively evaluated.

Results

The clinical and radiology follow-up indicated a stable arthrodesis and clinical relief from symptoms for all patients. All patients with neurological defects improved an average of 1.33 grade at their most recent clinical assessment, P < 0.05; their average admission ASIA motor score, pin prick score and light touch score improved to an average follow-up ASIA score of 99.80 (99.83 ± 0.38), 111.83 (111.83 ± 0.45), and 111.89 (111.89 ± 0.32), respectively. No neurovascular impairment and case of implant failure were observed.

Conclusions

The C1–2 transarticular screws combined with C1 laminar hooks fixation is a reliable technique for atlantoaxial instability.