Development of high oxidation resistant coating of nanostructured MgO on carbon nanotubes via simple precipitation technique in Mg/CO gas system

The synthesis of oxide-coated carbon nanotubes (CNTs) by a simple precipitation reaction in Mg/CO gaseous system was studied. The results showed that nanostructured MgO could be uniformly coated on the surface of CNTs via inhomogeneous Mg_(g) and CO_(g) precipitation reaction. Furthermore, we have developed a mixing procedure based on simultaneous agitation and ultra-sonication in order to break CNT bundles and prepare highly dispersed starting materials. By applying such mixing procedure, dispersed and distinct nano-oxide coated CNTs were synthesized which can be efficiently utilized in different composite matrices. Oxidation resistance of samples was investigated by DSC/TG thermal analysis. The results showed that oxide-coated CNTs present superior resistance against oxidation even at rather elevated temperature of 1000 °C and total weight loss of coated CNTs was measured to be less than 1 wt% during heat treatment at such temperature. Finally, coating adhesion was evaluated employing ultrasonic waves (as mechanical force) and subsequent weight loss measurement at temperature of 1000 °C.     

Magnetic and bioactive properties of MnO2/Fe2O3 modified Na2O-CaO-P2O5-SiO2 glasses and nanocrystalline glass-ceramics

Glass and in-situ nanocrystalline glass-ceramics of compositions 45SiO₂-25CaO-10Na₂O-5P₂O₅-xFe₂O₃-(15-x) MnO₂ are investigated for their magnetic and in-vitro bioactive properties. The ferrimagnetic character is observed in the high Fe₂O₃ containing in-situ nanocrystalline glass-ceramics. Saturation magnetization and coercivity increases with Fe₂O₃. After soaking in the simulated body fluid (SBF), the powdered as well as the bulk glasses and glass-ceramics are investigated using various characterization techniques. The presence of MnO₂ increases the leaching of Na⁺ ions from the glasses and also attracts the Ca²⁺ cations from the SBF as compared to Fe₂O₃ containing nano-crystalline glass-ceramics. It also increases the tendency to form hydroxyl apatite (HAp) layer. Microwave Plasma Atomic Emission Spectroscopy (MP-AES), Fourier Transform Infrared (FTIR) spectra, X-ray diffraction and Scanning electron micrographs (SEM) after soaking in the SBF confirm the HAp formation on the surface of all the glasses and glass-ceramics. Urbach energy also indicates the structural modifications on the surfaces of the glass and glass-ceramics after soaking in the SBF.     

Resveratrol Attenuates Acute Inflammatory Injury in Experimental Subarachnoid Hemorrhage in Rats via Inhibition of TLR4 Pathway

Toll-like receptor 4 (TLR4) has been proven to play a critical role in neuroinflammation and to represent an important therapeutic target following subarachnoid hemorrhage (SAH). Resveratrol (RSV), a natural occurring polyphenolic compound, has a powerful anti-inflammatory property. However, the underlying molecular mechanisms of RSV in protecting against early brain injury (EBI) after SAH remain obscure. The purpose of this study was to investigate the effects of RSV on the TLR4-related inflammatory signaling pathway and EBI in rats after SAH. A prechiasmatic cistern SAH model was used in our experiment. The expressions of TLR4, high-mobility group box 1 (HMGB1), myeloid differentiation factor 88 (MyD88), and nuclear factor-κB (NF-κB) were evaluated by Western blot and immunohistochemistry. The expressions of Iba-1 and pro-inflammatory cytokines in brain cortex were determined by Western blot, immunofluorescence staining, or enzyme-linked immunosorbent assay. Neural apoptosis, brain edema, and neurological function were further evaluated to investigate the development of EBI. We found that post-SAH treatment with RSV could markedly inhibit the expressions of TLR4, HMGB1, MyD88, and NF-κB. Meanwhile, RSV significantly reduced microglia activation, as well as inflammatory cytokines leading to the amelioration of neural apoptosis, brain edema, and neurological behavior impairment at 24 h after SAH. However, RSV treatment failed to alleviate brain edema and neurological deficits at 72 h after SAH. These results indicated that RSV treatment could alleviate EBI after SAH, at least in part, via inhibition of TLR4-mediated inflammatory signaling pathway.     

临床试验逻辑核查的分类及应用

临床试验数据的清理是临床试验过程中非常重要的环节,完整、清洁的数据才能用于统计分析。本文旨在讨论临床试验数据清理过程中数据核查计划的撰写及逻辑核查的分类等,并进一步讨论近年来临床试验数字化趋势对数据的采集及清理可能带来的影响。     

面向等离子体W材料改善韧性的方法与机制

目的: 探讨胰岛素样生长因子1（IGF-1）基因多态性与抗高血压药物治疗后血压水平的关联性。方法: 运用流行病学现况调查方法,收集服用复方利血平、降压片和珍菊降压片的780例高血压患者的一般临床特征并测量其血压和临床生化指标。选择IGF-1基因的5个标签位点,采用TaqMan技术进行基因分型。采用协方差分析及分层分析对其基因多态性与药物治疗后血压水平的关系进行评价。结果: 在服用降压片的高血压病人中,rs6219位点不同基因型之间舒张压水平差异有统计学意义（P=0.01）。在服用复方利血平的高血压病人中,rs5742612和rs6218位点不同基因型之间收缩压水平差异有统计学意义（P值分别为0.04、0.017）。在服用珍菊降压片的高血压患者中,rs6218位点不同基因型之间舒张压水平及rs6219位点不同基因型之间收缩压水平差异均有关联（P值分别为0.017、0.033）。进一步分层分析发现,服用降压片的患者中,随着rs35767位点遗传变异女性收缩压的水平呈线性下降,而男性舒张压水平呈线性上升,校正混杂因素后P值分别为0.028、0.038。结论: IGF-1基因多态性与复方利血平、降压片和珍菊降压片三种抗高血压药物治疗后血压水平均有显著相关,提示IGF-1基因可能是高血压重要的药物疗效生物标记。     

Hydrothermal synthesis and spark plasma sintering of NaY zeolite as solid-state matrices for cesium-137 immobilization

Hydrothermal synthesis of NaY-type zeolite was carried out and the effect of temperature on the phase composition, crystal structure, textural characteristics, particle size and morphology, as well as sorption properties to Cs⁺ ions was studied. Solid-state matrices based on NaY zeolite the Faujasite structure containing 26.1 wt% cesium were obtained by spark plasma sintering (SPS) with high values of compressive strength (to 132.9 MPa) and Vickers microhardness to HV~ 698, Fracture toughness (K_1c) ~ 1.26 MPa m^1/2. The kinetics of ceramic matrices consolidation, phase composition and morphology using dilatometric studies, XRD, and SEM were studied. The thermogravimetric analysis shown the high thermal stability of the obtained samples up to 1300 °C. The high hydrolytic stability of CsAlSiO₄ ceramic was proven (leaching rate of 2.33 ×10^?8 g·cm^?2·day^?1 and cesium diffusion coefficient De 1.41 ×10^?13), which exceeds the requirements of GOST R 50926–96 and ISO 6961:1982 for solid-state matrices.     

A pyramid algorithm for fast curve extraction

The human visual system has the impressive ability to quickly extract simple, global, curvilinear structure from input that may locally not even contain small fragments of this structure. Curves are easy to see globally even when they are locally broken, blurred, or jagged. Because the character of curve input can change with the scale at which it is considered, a hierarchical “pyramid” data structure is suggested. This paper describes a simple curve extraction process involving only local isotropic parallel operations. The noise-cleaned input image is smoothed and subsampled into a pyramid of lower-resolution versions by recursive computation of Gaussian-weighted sums. Curves are localized to thin strings of ridges and peaks at each scale. The method is compared with more abstract, essentially one-dimensional contour summarization processes.     

肿瘤热疗用锰锌铁氧体磁性纳米粒的制备及表征

以硫酸盐为原料,氢氧化钠为沉淀剂制备了不同化学组成的纳米级锰锌铁氧体,采用X射线衍射分析（XRD）、透射电镜（TEM）及热重分析系统对其进行表征;并探讨了在20℃室温,200kHz的交变磁场下锰锌铁氧体磁流体热效应情况。实验结果表明：制备的锰锌铁氧体为尖晶石结构,圆形,平均粒径在50nm左右,粒度较均匀,居里温度随Zn^2＋含量的增加而降低;其在交变磁场作用下具有明显的热效应,升温可至肿瘤热疗的有效温度范围;且升温的速度及恒定时的温度与锰锌铁氧体的含量、磁场强度有关,含量高,场强大,升温速度快,恒定温度高;另外,在其它条件相同时,恒定时所能达到的温度随Zn^2＋含量的增加而降低。本研究为肿瘤热疗的控温、恒温奠定了基础。     

Solid state characterization and x-ray crystal structure of a 1:1 complex of tetrathiafulvalene and meta-dinitrobenzene (TTF-mDNB)

A crystalline 1:1 complex of tetrathiafulvalene and meta-dinitrobenzene has been prepared in high yield and characterized by i.r. and u.v. spectroscopies, e.s.r. and bulk magnetic susceptibility data, four-probe d.c. conductivity and single-crystal X-ray analysis. It is a neutral complex with low conductivity, σ_rt = 2.7 × 10⁻⁹ S cm⁻¹, and has a mixed stack structure.