过渡金属元素(Fe与Cr)掺杂Bi4Si3O12晶体闪烁性能的研究

本文采用坩埚下降法生长出20mm×20mm×100mm优质Bi₄Si₃O₁₂及Fe、Cr掺杂Bi₄Si₃O₁₂晶体．测试了晶体的透射光谱、能谱及光产额、FWHM能量分辨率和激发一发射光谱．总结并解释了掺杂影响Bi₄Si₃O₁₂晶体闪烁性能的规律．     

Advanced ART2 scheme for enhancing metrology-data-quality evaluation

The metrology-data-quality-index (DQI_y) algorithm was proposed to perform metrology-data-quality evaluation of the automatic virtual metrology system developed by the authors. The DQI_y algorithm is based on the adaptive-resonance-theory 2 (ART2). ART2 divides data into different patterns according to the similarity of process data, and then calculates the corresponding DQI_y value and its threshold, DQI_yT, for evaluation and judgment. However, in practical applications, the classical ART2 technique still could not cluster process data very precisely. Since some samples with dissimilar process parameters might be sorted into the same cluster, two or more groups could be found in the corresponding metrology-data cluster. This phenomenon may cause invalid DQI_y detection. To solve the problem above, the advanced ART2 scheme is proposed in this paper to enhance the accuracy of the DQI_y algorithm. A large industrial data-set showing both a shift in metrology measurements without a process shift and a process shift that was not captured by the metrology of the actual photo and color-filter production tools of a TFT-LCD factory were adopted as illustrative examples to verify the practicality of the proposed scheme. Experimental results show that the performance of the advanced ART2 is indeed better than that of the original ART2.     

The joint model of the logistic model and linear random effect model — An application to predict orthostatic hypertension for subacute stroke patients

Stroke is a common acute neurologic and disabling disease. Orthostatic hypertension (OH) is one of the catastrophic cardiovascular conditions. If a stroke patient has OH, he/she has higher chance to fall or syncope during the following courses of treatment. This can result in possible bone fracture and the burden of medical cost therefore increases. How to early diagnose OH is clinically important. However, there is no obvious time-saving method for clinical evaluation except to check the postural blood pressure.This paper uses clinical data to identify potential clinical factors that are associated with OH. The data include repeatedly observed blood pressure, and the patient’s basic characteristics and clinical symptoms. A traditional logistic regression is not appropriate for such data. The paper modifies the two-stage model proposed by Tsiatis et al. (1995) and the joint model proposed by Wulfsohn and Tsiatis (1997) to take into account of a sequence of repeated measures to predict OH. The large sample properties of estimators of modified models are derived. Monte Carlo simulations are performed to evaluate the accuracy of these estimators. A case study is presented.     

A Novel Relative High-Density Lipoprotein Index to Predict the Structural Changes in High-Density Lipoprotein and Its Ability to Inhibit Endothelial–Mesenchymal Transition

Therapeutic elevation of high-density lipoprotein (HDL) is thought to minimize atherogenesis in subjects with dyslipidemia. However, this is not the case in clinical practice. The function of HDL is not determined by its concentration in the plasma but by its specific structural components. We previously identified an index for the prediction of HDL functionality, relative HDL (rHDL) index, and preliminarily explored that dysfunctional HDL (rHDL index value > 2) failed to rescue the damage to endothelial progenitor cells (EPCs). To confirm the effectiveness of the rHDL index for predicting HDL functions, here we evaluated the effects of HDL from patients with different rHDL index values on the endothelial–mesenchymal transition (EndoMT) of EPCs. We also analyzed the lipid species in HDL with different rHDL index values and investigated the structural differences that affect HDL functions. The results indicate that HDL from healthy adults and subjects with an rHDL index value < 2 protected transforming growth factor (TGF)-β1-stimulated EndoMT by modulating Smad2/3 and Snail activation. HDL from subjects with an rHDL index value > 2 failed to restore the functionality of TGF-β1-treated EPCs. Lipidomic analysis demonstrated that HDL with different rHDL index values may differ in the composition of triglycerides, phosphatidylcholine, and phosphatidylinositol. In conclusion, we confirmed the applicability of the rHDL index value to predict HDL function and found structural differences that may affect the function of HDL, which warrants further in-depth studies.     

Enhanced antioxidant activity of Monascuspilosus fermented products by addition of ginger to the medium

The fermented products of Monascus sp. are known for their antihypercholesterolaemic effects, however, their antioxidant activities are different from those of many plant-derived foods. To evaluate the effect of ginger addition into the medium on the antioxidant activity of Monascuspilosus fermented products, we cultured uninoculated PDB medium (PDB), inoculated PDB medium (MP), uninoculated ginger-containing medium (PDBG), and inoculated ginger-containing medium (MPG). The broth and mycelia were collected, freeze-dried, and extracted to evaluate their free radical scavenging activities, inhibition of peroxidation, phenolic content, inhibition of DNA damage, cellular antioxidant activity, and expression of the antioxidant enzymes. The results showed that MPG had significantly higher antioxidant activity than PDB, MP, and PDBG at all fermentation time points. Moreover, the fermentation process significantly increased the antioxidant activities of MPG. After the inherent level of antioxidant capacity was increased, the modified M. pilosus fermented product demonstrated a higher anti-atherosclerotic value than the unmodified product.     

Fabrication of Pt nanoparticles decorated PPy–MWNTs composites and their electrocatalytic activity for methanol oxidation

Here we report the synthesis and characterization of a catalyst material constituted of Pt, polypyrrole (PPy) and multi-walled carbon nanotubes (MWNTs). The catalyst supports (PPy–MWNTs nanocomposites) were synthesized via in situ chemical polymerization in advance, in which MWNTs were regarded as the matrix material. The supports were characterized by SEM & TEM, elemental analysis, XRD, FTIR and conductivity measurements. Then the catalysts were synthesized by a chemical reduction using sodium borohydride (NaBH₄) as reducing agent and acetic acid buffer (pH = 4) containing trace K₂C₂O₄ as reaction media. FTIR spectra showed that there existed relations between PPy and MWNTs during in situ polymerization. SEM and TEM micrographs of the catalyst samples exhibited that the existence of PPy layer which was evenly wrapped on the surface of MWNTs resulted in significant improvement in helping Pt particles well dispersed. XRD results showed that higher Pt(1 1 1) content in the catalyst deposited on PPy–MWNTs supports than that on MWNTs. The cyclic voltammetry (CV) tests of methanol electrocatalytic oxidation demonstrated that the electrode modified by Pt/PPy–MWNTs ternary composite catalyst showed higher catalytic stability than Pt/MWNTs binary catalyst, due to the synergic interaction between Pt and the carrier.     

分子超光谱成像系统应用于糖网病药物疗效研究

将成像技术和光谱技术相结合,再配合显微镜技术,研制了基于AOTF(acousto-optic tunable filters)的分子超光谱成像系统.使用该系统采集了正常、糖尿病和EPO(erythropoietin,促红细胞生长素)药物治疗的大鼠视网膜组织切片的分子超光谱图像数据.通过对正常组、糖尿病组、药物治疗组共30例样本的分子超光谱图像数据进行处理,获得了3组样本的单波段图像和伪彩色合成图像,并提取了各组样本外核层的典型透射光谱曲线.从图像上分析各组ONL(outer nuclear layer,外核层)的厚度,由大到小依次为正常组、治疗组、糖尿病组,由于糖尿病会引起视网膜外核层细胞凋亡和厚度减少,实验结果表明经EPO治疗后可增加视网膜外核层的厚度.从光谱上分析各组的透射强度,糖尿病大鼠视网膜外核层组织在550～1000 nm光谱范围内的透射强度整体高于正常组,经EPO治疗后,透射强度介于正常组和糖尿病组之间;通过光谱相似性分析,治疗组与正常组之间的光谱相似性高于糖尿病与正常组.实验结果表明EPO能减少视网膜外核层细胞凋亡,对糖网病大鼠有一定的疗效.因而分子超光谱成像系统可以作为一种新的手段,辅助科研人员对糖网病的发病机理和致盲原因及药物疗效进行研究.     

Antioxidant and Anti-Inflammatory Properties of Lower-Polymerized Polyphenols in Oolong Tea

This study investigated the antioxidant and anti-inflammatory properties of the fractionated tea extract, a lower-polymerized polyphenol-rich extract ultrafiltrated from oolong tea. The amounts of total polyphenols, flavonoids and condensed tannin were enriched in fractionated tea extract compared to oolong tea. Furthermore, fractionated tea extract was a stronger scavenger of nitric oxide and 2,2-diphenyl-1-picryhydrazyl radicals than oolong tea. When lipopolysaccharide-treated RAW264.7 macrophages were co-incubated with both tea extracts (500 μg/mL) or (-)-epigallocatechin gallate (100 μg/mL) for 16 h, all samples (oolong tea, fractionated tea extract, and (-)-epigallocatechin gallate) suppressed nitric oxide production by 60, 48, and 46%, respectively, and the suppression was due to nitric oxide-scavenging. However, only fractionated tea extract lowered the proportion of phospholipid arachidonic acid and type II-cyclooxygenase expression, thereby decreasing PGE₂ synthesis by 29%. In conclusion, fractionated tea extract was rich in potent antioxidant substances capable of inhibiting the production of pro-inflammatory mediators.     

Synthesis and characterization of dual stimuli-responsive block copolymers based on poly(N-isopropylacrylamide)-b-poly(pseudoamino acid)

The current study synthesized amphiphilic thermal/pH-sensitive block copolymers PNiPAAm-b-PHpr by condensation polymerization of trans-4-hydroxy-l-proline (Hpr) initiated from hydroxy-terminated poly(N-isopropylacrylamide) (PNiPAAm) as the macroinitiator in the presence of the catalyst, SnOct₂. ¹H NMR, FTIR, and gel permeation chromatography (GPC) characterized these copolymers. Their solutions showed reversible changes in optical properties: transparent below a lower critical solution temperature (LCST) and opaque above the LCST. The LCST values depended on the polymer composition and the media. With critical micelle concentrations (CMCs) in the range of 1.23-3.73 mg L⁻¹, the block copolymers formed micelles in the aqueous phase owing to their amphiphilic characteristics. Increased hydrophobic segment length or decreased hydrophilic segment length in an amphiphilic diblock copolymer produced lower CMC values. The current work proved the core-shell structure of micelles by ¹H NMR analyses of the micelles in D₂O. Transmission electron microscopy analyzed micelle morphology, showing a spherical core-shell structure. The micelles had an average size in the range of 170˜210 nm (blank), and 195˜280 nm (with drug). Observations showed high drug entrapment efficiency and drug-loading content for the drug micelles.     

Improvement of the functionality of a potential fruit insoluble fibre by micron technology

An insoluble food fibre was micronised to different microsizes (6.77–29.5 μm) by three different micron technologies using optimised conditions. The effects of different micronisation treatments and particle sizes on the characteristics and various physicochemical properties of this insoluble fibre were studied. As particle size decreased, the bulk density of the insoluble fibre was significantly (P < 0.05) decreased. A redistribution of fibre components from insoluble to soluble fractions was observed. The treatments, especially the high‐pressure micronisation, effectively (P < 0.05) increased the physicochemical properties (e.g. water‐holding capacity, swelling capacity, oil‐holding capacity, cation‐exchange capacity and glucose‐adsorption capacity) and also the inhibitory activity towards α‐amylase and pancreatic lipase of the insoluble fibre to different extent (from several up to c. fifteenfold). Our results suggested that micronisation treatments would provide an opportunity to improve the functionality of the insoluble fibre and exploit its potential applications as a functional ingredient in fibre‐rich products.