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61.
62.
目的 探讨C 反应蛋白(CRP)急性期快速上升能否可靠预测非创伤性急腹症的CT 检查阳性表现。方法 收集CRP 检测后24h内行腹盆、腔CT扫描的非创伤性急腹症患者121 例,其中男57例,女64例,平均年龄57岁。近期手术、已知恶性肿瘤、炎症性肠病除外。CT表现由2 位放射科医师阅片并一致后进行分类。结果 CRP 正常CT 检查阳性16 人,阴性15 人,随着CRP 升高,CT 检查阳性率也随着升高,灵敏度下降,特异度增高,似然比也随之增高,当CRP 在130mg/L 水平以上时,其灵敏度与特异度分别为31.4%、90.9%,阳性似然比为3.14。结论 CRP阴性的非创伤性急腹症患者,不能除外CT 检查,随着血清CRP 水平升高,CT检查阳性率及阳性似然比也随之升高。 相似文献
63.
Dai J Bao Z Sun L Hong SU Baker GL Bruening ML 《Langmuir : the ACS journal of surfaces and colloids》2006,22(9):4274-4281
Polymeric coatings with high protein-binding capacities are important for increasing the output of affinity-based protein purification and decreasing the detection limits of antibody microarrays. This report describes the use of thick poly(acrylic acid) (PAA) brushes to immobilize as much as 80 monolayers of protein. The brushes were prepared using a recently developed procedure that allows polymerization of 100-nm-thick poly(tert-butyl acrylate) films from a surface in just 5 min along with hydrolysis of these films to PAA in 15 min. Covalent binding of bovine serum albumin (BSA) to PAA brushes that were activated using standard coupling agents, however, resulted in immobilization of less than two monolayers of BSA because of competitive hydrolysis of the esters in the activated film. In contrast, derivatization of PAA with nitrilotriacetate (NTA)-Cu2+ complexes yielded films capable of binding many monolayers of protein via metal-ion affinity interactions. For example, derivatization of 55-nm-thick PAA films with NTA-Cu2+ allowed immobilization of about 15 monolayers (5.8 microg/cm2 or 58 nm) of BSA. The binding capacity was even higher for myoglobin (7.7 microg/cm2) and anti-IgG (9.6 microg/cm2). Remarkably, electrostatic adsorption of lysozyme in 55-nm-thick, underivatized PAA resulted in as much as 80 monolayers (16.2 microg/cm2 or 162 nm) of adsorbed protein. Polymer synthesis, derivatization, and swelling, as well as BSA immobilization kinetics and thermodynamics were characterized using reflectance FT-IR spectroscopy, ellipsometry, and protein assays. 相似文献
64.
This report describes the remarkably rapid synthesis of polymer brushes under mild conditions (50 degrees C) using surface-initiated polymerization. The highly active atom transfer radical polymerization catalyst Cu(I)-1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane allows synthesis of 100 nm thick poly(tert-butyl acrylate) brushes from initiator-modified Au surfaces in just 5 min. Using the same catalyst, polymerization of 2-hydroxyethyl methacrylate and methyl methacrylate yielded 100 nm thick films in 10 and 60 min, respectively. Such growth rates are an order of magnitude greater than those for traditional free-radical polymerizations initiated from surfaces. These polymerizations also retain some features of controlled radical polymerizations, such as the ability to form block copolymer brushes. 相似文献
65.
采用离子色谱法同时测定了牙膏中游离氟与单氟磷酸盐的含量。结果表明,该法具有简单、准确、快速等特点,可以在牙膏产品检测中推广使用。 相似文献
66.
Xi Z Zhang WX Song Z Zheng W Kong F Takahashi T 《The Journal of organic chemistry》2005,70(22):8785-8789
[reaction: see text] Vinyl allenes were prepared in high yields by the Wittig-Horner reaction of 1-lithio-1,3-dienyl phosphine oxides with aldehydes. 1-Lithio-1,3-dienyl phosphine oxides were generated in situ from lithiation of 1-iodo-1,3-dienyl phosphine oxides, which were obtained by iodination of alpha-phosphinozirconacyclopentadienes. As a whole, a vinyl allene is synthesized from two different alkynes and one aldehyde. 相似文献
67.
Four new paranmeters, and , and have been proposed to describe the average length of the sequence of substituted anhydroglucose units and that of unsubstituted ones respectively along the CMC chain. The methods for determining those parameters have also been presented . Six CMC samples have been characterized in terms of intrinsic viscosity, degree of substitution (DS), index of substitution(SI)_ and . It has been proved experimentally that, not only can describe the sequence distribution along the CMC chain, but also can be used for calculating SI and estimating the average degree of substitution in the substituted glucose rings. 相似文献
68.
69.
We observed and measured the relative carrier-envelope phase difference per round trip between synchronized femtosecond Ti:sapphire and Cr:forsterite mode-locked lasers. The relative carrier-envelope phase slip was directly recorded by heterodyning of the Cr:forsterite laser with the supercontinuum from the Ti:sapphire laser. We also obtained another phase relation by superimposing the third harmonic of the Cr:forsterite laser with the second harmonic of the Ti:sapphire laser. In the latter case we obtained a stable beat signal with a signal-to-noise ratio larger than 30 dB and found a dependence of the beat frequency on the cavity length. 相似文献
70.
云状空化非定常脱落机理的数值与实验研究 总被引:1,自引:0,他引:1
结合数值计算和实验技术研究了云状空化的非定常脱落机理. 实验采用高速录像技术观察了绕Clark-y型水翼云状空化形态随时间的变化. 数值计算采用了汽-液两相的当地均相流模型,湍流封闭采用了一种修正的RNG k-\varepsilon方程,利用商业软件的二次开发技术,引入了一种与空化区域水汽相密度相关的系数,对湍流模型进行了修正. 计算和实验结果均表明:云状空化尾部存在着准周期性的涡状空化团的脱落;局部压强的增加是引起空穴断裂进而脱落的直接原因;压强升高是由于近壁处的反向射流引起的;空穴尾部的大规模的旋涡运动引起的近壁处的逆压梯度是引起反向射流的主要原因. 相似文献