利用提升小波的蛋白质相互作用特征提取

利用提升小波从蛋白质序列中提取出它们相互作用的频谱特征,经支持向量机训练学习后,用于预测蛋白质间的相互作用.模拟计算结果表明,在阳性数据和阴性数据平衡的前提下,利用提升小波获取的低维蛋白质相互作用特征向量可以得到较高预测精度.进一步阐述了不同物种的蛋白质相互作用网络有着不同特征,为了得到更准确的预测结果,需要利用不同的方法提取蛋白质相互作用的特征.     

单矢量水听器估计目标方位的方法与实验

为评估基于单矢量水听器的方位估计能力,在黄海海域对矢量水听器进行实验。矢量水听器吊放于接收船尾部,采用平均声强器和复声强器方位估计方法,并提出以概率密度值最大的方位角作为目标方位估计值的具体处理准则,对恒定方向、匀速行驶的目标船方位进行估计,并求出两种方法的方位估计误差。结果表明,水听器布放深度10 m时,对正横距离为0.42 km的航速10 kn的目标船,平均声强器方法的水平方位角估计误差18°,极角估计误差为5°,可以在离目标船最远1.17 km处估计其方位;复声强法的水平方位角估计误差为13°,极角估计误差为8°,可以在离目标船最远2.35 km处估计其方位。在有接收船的噪声干扰情况下,复声强器比平均声强器方法估计的方位更准确,可以对更远处的噪声源进行方位估计。     

A Water-Soluble Synthetic Bilirubin with Carboxyl Groups Replaced by Sulfonyl Moieties

 The first symmetrical bilirubin analog with CO₂H groups replaced by SO₃H, 8,12-bis-(2-sulfo-ethyl)-3,17-diethyl-2,7,13,18-tetramethyl-(10H,21H,23H,24H)-bilin-1,19-dione, was synthesized from methyl (2,4-dimethyl-5-ethoxycarbonyl-1H-pyrrol-3-yl) acetate in nine steps via the sulfonic acid analog of xanthobilirubic acid (XBR) and isolated as its disodium salt. The sulfonic acid group was introduced at an early stage of the synthesis by reaction of an intermediate, ethyl 4-(2-bromoethyl)-3,5-dimethyl-1H-pyrrole-2-carboxylate, with sodium sulfite. The disodium bilirubin disulfonate exhibits NMR spectroscopic properties rather similar to those of the parent carboxylic acid, mesobilirubin-XIIIα; however, its UV/Vis spectra are blue-shifted and broadened relative to those of the parent compound. Like mesobilirubin, the disulfonate displays a positive exciton chirality circular dichroism spectrum, albeit with weaker Cotton effects, in a buffered aqueous solution (pH = 7.4) containing a 2:1 molar ratio of human serum albumin.     

Water-soluble xanthobilirubinic acids?

Abstract  Xanthobilirubinic acid, a model dipyrrinone for one-half of the bilirubin molecule in photochemical and metabolism studies, is more polar than bilirubin and insoluble in water and in chloroform. Replacing the β-alkyl substituents on the lactam ring of xanthobilirubinic acid with methyl-capped ethylene glycol, diethylene glycol, and triethylene glycol (PEG) groups steadily increased the water solubility of the pigment so that the last is completely soluble in both water and chloroform. Synthesized by base-catalyzed condensation of the corresponding methyl-capped 3,4-diPEG-pyrrolin-2-one with 3,5-dimethyl-4(2-ethoxycarbonylethyl)-2-formyl-1H-pyrrole, these new PEGylated analogs of xanthobilirubinic acid are yellow-colored dipyrrinones that form intermolecular hydrogen-bonded dimers in chloroform solution but are monomeric in methanol and water, as revealed by ¹H NMR spectroscopy and vapor pressure osmometry. Methyl xanthobilirubinate has served as a synthetic precursor to bilirubinoids; its amphiphilic PEGylated analogs suggest a route to water-soluble bilirubinoids and biliverdinoids. Graphical abstract        

3,3,6,6-四甲基-9-邻氯苯基-1,8-二氧代-3,4,5,6,7,9-六氧化氧杂蒽的合成和晶体结构

标题化合物C23H25对O3Cl是由邻氯苯甲醛与5，5-二甲基1，3-环己二酮在N，N-二甲基甲酸腹中反应而得。结构通过单晶X-射线衍射法确定，其晶体属于单科晶系，空间群=1632。晶体结构用直接法解出，使用全矩阵最小二乘法对原子参数进行修正，最后的偏离因子为R=0．054，Rw一0．063。在晶体结构中，吡喃环与苯环之间的两面角为92．43°。     

脱叔丁基杯[8]芳烃键合固定相的制备及其液相色谱性能

杯芳烃(Cahixarenes)是一类由苯酚单元经亚甲基相连而成的大环化合物,与β-环糊精类似,它能与多种溶质形成主客体包容配合物,并通过超分子作用识别离子和中性分子等客体,利用杯芳烃的分子识别作用可提高色谱分离性能,Glennon等制备了酯化杯[4,6]芳烃键合固定相,     

邻硝基乙酰苯胺衍生物的XPS振起伴峰及其价带谱的研究

研究了一组邻硝基乙酰苯胺衍生物的X射线光电子能谱(XPS).观察到硝基的N1s光电子谱有明显分裂,可认为是N1s振起伴峰的反映,而且苯环上的取代基对该振起伴峰强度有影响,按照Pignataro等关于振起伴峰与主峰的能量分离以及分子内电荷转移有关的观点,计算了振起伴峰与主峰的面积比.结果表明,峰间距与面积比的趋势一致.因此二者都可作为分子内电荷转移的粗略估计.     

Bi4V2O11/石墨烯异质结光催化剂的制备及其在降解抗体污染物中应用

发展和设计高效、廉价和稳定的光催化剂用于抗生素污染物降解仍然存在巨大的挑战。 本文通过一种便捷的水热方法制备了Bi₄V₂O₁₁/石墨烯复合材料并用于可见光下抗生素污染物光催化降解。 通过自由基追踪实验,确认了光催化降解过程中活性物质为h⁺和·OH基团。 根据实验结果,提出了相应的反应机理。 石墨烯的引入可以有效地促进光生电子-空穴对的分离,从而增强光催化活性。 该复合催化剂展现出良好的活性和稳定性。 该方法以石墨烯为载体制备了光催化降解材料,为高性能光催化剂的制备提供了参考。     

Fluorophenyl Bilirubins: Synthesis and Stereochemistry

 Analogs of bilirubin with vinyl groups replaced by symmetrically-disposed o-fluorophenyls (1, bis-exo, and 2, bis-endo) were synthesized and characterized spectroscopically. Their ¹H NMR spectra and NOE data are consistent with an intramolecularly hydrogen-bonded ridge-tile conformation where each propionic acid group embraces an opposing dipyrrinone. Like bilirubin, 1 and 2 exhibit negative chirality induced circular dichroism (ICD) Cotton effects in chloroform containing quinine. Unlike bilirubin, however, in aqueous buffer containing human serum albumin, 2 exhibits a negative exciton chirality ICD, whereas that of 1 is positive.     

Synthesis of bilin-1,19-diones and biladiene-ac-1,19-diones with c(10) adamantyl and tert-butyl groups

Bilirubin and biliverdin analogs bearing bulky adamantyl and tert-butyl groups at the central C(10) position were synthesized and their structures were analyzed by nmr and ultraviolet-visible spectroscopy and by molecular mechanics calculations, all of which collectively indicated a preference for helical conformations.