纳米酶侧流免疫层析法快速检测食品中肠炎沙门氏菌

目的 基于氧化铈修饰的金纳米棒(CeO2 modified Au nanorod, AuNR@CeO2)纳米酶构建纳米酶侧流免疫层析法(lateral flow immunoassay, LFIA), 并用以检测食品中肠炎沙门氏菌。方法 采用模板法制备AuNR@CeO2纳米酶, 对纳米酶的酶促活性进行考察。将AuNR@CeO2标记抗体作为信号探针进一步构建试纸条, 优化其关键参数, 并利用AuNR@CeO2纳米酶的酶促活性, 催化放大试纸条的比色信号, 最后将其用于奶粉中肠炎沙门氏菌的检测。结果 成功制备了AuNR@CeO2纳米酶, 在最优条件 下(即：2% BSA+0.05% Tween-20的样品垫缓冲体系、0.8 mg/mL的T线抗体质量浓度和4 μL的探针使用量), 该试纸条可以实现目标菌的特异性检测, 检出测限 低至103 CFU/mL, 信号放大后灵敏度提高了10倍, 在人工污染奶粉样品中也表现出良好的检测效果 检出限低至103 CFU/mL。结论 本研究所制备的试纸条无需复杂仪器和专业人员即可实现目标物的检测, 且具有易操作、便携、快速的特点, 通过更换抗体类型便可用于各类食品有害物质的检测。     

模具结构对铝合金挤压的影响机理

对不同模角挤压过程进行了数值模拟,研究了成形过程中金属的变形流动规律,并利用应力场特征薰进行了变形分区及应力应变分析。结果表明：随着模角的增大,塑性区的范围明显缩小。揭示了不同的变形条件,改变了简内应力应变的分布关系,是影响金属变形流动行为的内因所在。     

Drift of Levitated/Suspended Body in High- Tc Superconducting Levitation Systems Under Vibration—Part I: A Criterion Based on Magnetic Force-Gap Relation for Gap Varying With Time

Levitation drift in the high-T_c superconducting levitation systems is directly related to the safe operation of the systems. In these levitation systems, the gap between a superconductor and a permanent magnet may decrease, increase, or keep unvarying with time. Based on the numerical simulations of the magnetic force-gap hysteresis relations of two different physical processes in field cooling, and the dynamic features at some given positions on major magnetic force-gap loops, a criterion described by the slopes of the given position on minor and major loops is proposed in this study. According to the suggested criterion, the drift phenomenon can be characterized by judging gap varying with time for a given levitation system. In addition, the characteristic of continuous space range of the equilibrium position of levitated/suspended body has been further exhibited from the numerical results.     

Epidermal and dermal phospholipids of the human eyelid: a 31P nuclear magnetic resonance spectroscopy study

The phospholipids of the skin are difficult to quantify because they represent only a small fraction of the skin tissue. In this study, 31P nuclear magnetic resonance, which permits precise profiling of these phospholipids, was used to compare the phospholipids of upper eyelid epidermal and dermal lipid extracts (n = 13 profiles). Phospholipid profiles included alkylacylphosphatidylcholine (AAPC), dihydrosphingomyelin (DHSM), diphosphatidylglycerol (cardiolipin), ethanolamine plasmalogen (EPLAS), lysophosphatidylcholine, phosphatidic acid, phosphatidylcholine (PC), phosphatidylethanolamine, phosphatidylinositol, phosphatidylserine, sphingomyelin, and uncharacterized phospholipids (U1 and U2, particularly enriched in the epidermis). The computed phospholipid metabolic index (n = 86 indexes) findings can be summarized as follows: a lower content of the en-ol and ether phospholipids in the epidermis relative to the dermis, internal compensation among the component phospholipids so as to maintain the choline functional group ratio, and a greater concentration of hydroxyl-containing functional groups in the epidermis. A membrane index (fmem) value of -0.37 for the epidermis deviated considerably from the value of -0.06 characteristic of living membranes and the dermis. The production of the reduced phosphatides, EPLAS and AAPC, indicates the use of alternative pathways between the two tissues. Relative to the dermis, increased PC in the epidermis coupled with decreased DHSM, EPLAS, and AAPC are factors enabling the epidermis of eyelid tissue to be an effective water barrier.     

CuInSe2薄膜的化学溶液制备方法

采用了一种低成本化学溶液法制备铜铟硒(CuInSe_2,CIS)薄膜.研究了预退火温度、硒化温度及基片衬底等实验参数对材料性能的影响.采用硝酸铜和氯化铟配置前驱体溶液,旋涂法制膜,后经480℃硒化退火得到CIS薄膜.XRD测试结果表明薄膜结晶性良好,具黄铜矿结构;SEM测试结果显示薄膜由较大晶粒组成,表面相对平整致密;EDX测试显示薄膜组分相对合理,略贫Cu而富Se.采用此薄膜为吸收层制备CIS原型薄膜太阳能电池,其光电测试显示单层CIS光伏响应达到1.6%.     

Synthesis and electrocatalytic activity of multi-walled carbon nanotubes/Cu–Ag nanocomposites

Cu–Ag bimetallic nanoparticles with atomic ratio of 2.1:1 and diameter in the range of 15–30 nm were decorated on acid-treated multi-walled carbon nanotubes by a chemical reduction method, which was characterized by transmission electron microscope (TEM), X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and high-resolution transmission electron microscopy (HRTEM). The Cu–Ag/MWNTs nanocomposites were used to construct a modified electrode toward biosensing of H₂O₂ with a high sensitivity. The catalytic ability of MWNTs/Cu–Ag toward H₂O₂ was much better than that of MWNTs/Cu and MWNTs/Ag, which indicated that there is a cooperation effect between Cu and Ag.     

Acute angiographic and clinical results of long balloon percutaneous transluminal coronary angioplasty and adjuvant stenting for long narrowings

Historically, long coronary artery stenoses undergoing percutaneous transluminal coronary angioplasty (PTCA) are reported to have reduced procedural and clinical success in comparison with shorter lesions. The efficacy of long balloons (30 or 40 mm) in long lesions was evaluated. Eighty-two patients had 84 PTCA procedures with a primary long balloon. In all, 86 lesions were available for analysis. Data were collected prospectively on standard PTCA procedure forms. Coronary angiograms were reviewed and measured with digital calipers. Hospital charts were examined for complications. PTCA was performed in the left anterior descending artery in 44 cases (51%), the right coronary artery in 29 (34%) and the circumflex artery in 13 (15%). With the use of a modified classification system, 47 lesions (55%) were class C, 24 (28%) were class B2 and 15 (17%) were class B1. Mean lesion length was 22 +/- 11 mm (range 10 to 72), and 38 lesions (44%) were > or = 20 mm. Twelve patients received an intracoronary stent. The long balloon alone produced angiographic success (< 50% residual stenosis) in 77 lesions (90%). Angiographic success was achieved ultimately in all stenoses, using a stent in 7 patients and a short balloon in 2. There were 2 deaths (2%) and 1 Q-wave myocardial infarction (1%). One patient needed coronary artery bypass surgery. Clinical success without death, Q-wave infarction or bypass surgery was achieved in 83 of 86 procedures (97%). In conclusion, the use of long PTCA balloons with adjuvant stenting produced excellent results in these long stenoses. Lesion length was not a precursor of poor angiographic or clinical outcome.     

Pictorial review: the imaging features of male breast disease

Although breast carcinoma in men is rare, the presentation of a male patient with evidence of breast enlargement or of a palpable lump, is not uncommon. In such patients, radiological assessment may be requested to exclude malignant change. Mammography has been traditionally the dominant modality of investigation, although ultrasound, using high-frequency linear transducers, is playing an increasingly important role for both imaging and biopsy and the two techniques should be regarded as complementary. In this article the pathological conditions which may affect the male breast are reviewed and the imaging findings presented.     

Inhibin, activin and follistatin bind preferentially to the transformed species of alpha 2-macroglobulin

BACKGROUND AND PURPOSE: Radiation enteropathy is characterized by locally elevated levels of inflammatory and fibrogenic cytokines. Microvascular injury may sustain these alterations through persistent local hypercoagulopathy, platelet aggregation, leukocyte adhesion and release of biologically active mediators. This study assessed the relationship of endothelial thrombomodulin (TM), a key regulator of the protein C anticoagulant pathway and marker of endothelial function, with transforming growth factor beta (TGF-beta) immunoreactivity and morphologic alterations in radiation enteropathy. MATERIALS AND METHODS: Small bowel resection specimens from 9 patients with radiation enteropathy were analyzed by computerized quantitative immunohistochemistry using antibodies against TM, von Willebrand factor (vWF) and TGF-beta. Identical measurements were performed on intestinal resection specimens from otherwise healthy penetrating trauma victims and on archived small intestines. A previously validated image analysis technique was used to assess submucosal vessels for TM and vWF immunoreactivity, and the intestinal wall for total extracellular matrix-associated TGF-beta immunoreactivity. RESULTS: Specimens from irradiated patients showed prominent submucosal and subserosal thickening and fibrosis, and obliterative vasculopathy. Control specimens were histopathologically normal. Vascular density and vWF immunoreactivity were similar in radiation enteropathy patients and controls. The image-analysis techniques were highly reproducible, with correlation coefficients for repeated measurements ranging from 0.86 to 0.93. Radiation enteropathy specimens exhibited a highly significant reduction in the number and proportion of TM-positive submucosal vessels per unit area (P < 0.0001) and increased intestinal wall TGF-beta immunoreactivity (P = 0.002). CONCLUSIONS: These data support the theory that sustained endothelial dysfunction is involved in the molecular pathogenesis of radiation enteropathy, and point to TM as important in the chronic nature of radiation enteropathy and a potential target for prophylactic and therapeutic interventions.