Isolation of lappaconitine from Aconitum septentrionale roots by adsorption

Extracts of Aconitum septentrionale Koelle roots obtained using chloroform, isopropanol, and ethanol were purified using chloroform and basic γ-Al₂O₃. Ballast materials were selectively adsorbed by γ-Al₂O₃, increasing the mass fraction of lappaconitine in the extract. The ethanol extract was purified most. The degree of lappaconitine extraction by chloroform was unaffected by the presence of γ-Al₂O₃. However, the mass fraction in the extract and lappaconitine extraction from Aconitum septentrionale were increased more than twice. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 274–276, May–June, 2006.     

Bromsuperoxid: Bildung und Photoisomerisierung zu Bromdioxid

Bromine Superoxide: Generation and Photoisomerization into Bromine Dioxide Flash pyrolysis of a gas mixture containing bromine, oxygen and argon yields bromine superoxide, which can be identified IR- and UV-spectroscopically after trapping the pyrolysate at 12 K. Matrix irradiation transfers bromine superoxide into bromine dioxide. The backreaction can be induced by changing the wavelength. Even at room temperature a detectable amount of bromine superoxide is formed upon preparing a mixture of gaseous bromine, oxygen and argon.     

Preparative isolation of (+)-beta-eudesmol fromAmyris balsamifera

Summary Optically pure (+)-beta-eudesmol is a possible starting material for the synthesis of several termite defense compounds. A two step procedure for the isolation of gram quantities of (+)-beta-eudesmol from commercially availableAmyris balsamifera oil (syn. West Indian sandalwood oil), containing 8% beta-eudesmol, was developed. Step one consisted of an efficient vacuum distillation of the total oil. Step two was a medium pressure LC separation with an AgNO₃ impregnated silica gel stationary phase. Several other separation procedures failed due to the presence of many closely related sesquiterpene alcohols (75% of the oil).     

耐碳青霉烯酶肺炎克雷伯菌的分离鉴定及生物学特性分析

以临床尿路感染患者尿液为研究对象,通过分离培养及16s rDNA进行肺炎克雷伯菌的分离鉴定;采用Kirby-Bauer纸片法进行药敏实验,并对分离株进行碳青霉烯酶表型筛选;通过PCR检测常见的碳青霉烯酶耐药基因、荚膜血清型和毒力基因分布情况;对分离的肺炎克雷伯菌株进行了生物被膜形成能力及其对小鼠致病力的分析。本研究从采取的86例尿液标本中分离检出11株耐碳青霉烯酶肺炎克雷伯菌,分离率为12.79%。耐碳青霉烯酶基因PCR检测结果显示,blaNDM、blaVIM、blaIMP和blaKPC基因在分离株中均呈现不同程度的分布。耐药性分析发现11株肺炎克雷伯菌对氨苄西林耐药率为90.91%,对头孢噻肟耐药率为63.64%,对链霉素、庆大霉素、氯霉素和诺氟沙星的耐药率较低。耐碳青霉烯类肺炎克雷伯菌荚膜分型结果显示,分离的11株细菌中10株均为强毒力型菌株（90.9%）,其中K57血清型4株（36.4%）,K1血清型1株（9.1%）,K2血清型1株（9.1%）,K5血清型1株（9.1%）,K20血清型3株（27.3%）,提示该批分离株具有较强的致病力。此外,毒力因子分布结果显示,其毒力因子rmpA（54.5%）、Aerobactin F（54.5%）在菌株中分布较为广泛。生物被膜形成能力检测及小鼠致病性试验结果显示,9株分离株均有较强的生物被膜形成能力,菌株致病力可能与荚膜血清型及生物被膜形成能力相关。综上所述,临床分离的致尿路感染病原肺炎克雷伯菌呈现多重耐药特征,强毒力菌株以K57荚膜型为主,K1、K2均有分布,提示对尿路感染病原应加强耐药监测,合理使用抗菌药物,有效防控多重耐药和强毒力菌株的感染与流行。     

一种磁滞可调110/220 V自动切换系统

开发了１１０／２２０Ｖ电网自动切换系统,采用设置延迟时间和磁滞回线的方法,有效地防止了启动时误动作,避免在切换点附近频繁切换动作,讨论了延迟时间及磁滞回线回路的计算方法。     

免疫沉淀法分离纯化感染细胞中的甲肝病毒RNA

本研究采用抗血清（多抗血清）沉淀甲肝病毒,并用盐酸胍酸性酚,氯仿一步法分离纯化病毒ＲＮＡ．此方法能排除非病毒ＲＮＡ的污染,操作简单,要求条件较低,ＲＮＡ的纯度和完整性都较好     

一种同步转速状态测定方法及其实现

提出一种同步转速状态测定方法．基于该方法设计了采用霍尔传感器的单片机测量系统．实现了对双螺旋推进器的转速和瞬时相差的准确测量,解决了无法预报“碰撞”现象的难题     

Isolation of lipase producer and its performance in enantioselective hydrolysis of glycidyl butyrate

A racemic glycidyl butyrate resolving strain, preliminarily identified as a Rhizopus sp., had been isolated from soil. Its extracellular lipase was found to enantioselectively hydrolyze the (S)-enantiomer of the chiral ester, with optimal activities at pH 5.3 and 42°C. Higher en antioselectivity of theenzyme was observed at lower temperatures, while the best anantioselectivity was obtained at pH 5.5–6.0, with an, E value (enantiomeric ratio) of 57.     

Glucomannan from Narcissus poeticus Studied by PMR and 13C NMR Spectroscopy

Native acetylated glucomannan of molecular weight (MW) 32000 with a glucose:mannose ratio 1:30 was isolated from bulbs of Narcissus poeticus. Glucomannan was depolymerized to a fragment of MW 15000 with an unchanged primary structure and was studied using PMR and ¹³C NMR spectroscopy. It was found that the linear chain of the biopolymer consists of 1-4-bound D-gluco- and D-mannopyranose units and the O-Ac groups are localized on C-2, C-3, and C-6 hydroxyls in certain anhydromannose units.     

Thioacetylacetone: structural and vibrational assignments.

Thioacetylacetone and its variously deuterated isotopomers have been investigated using electronic and vibrational spectroscopy combined with quantum chemical calculations. Thioacetylacetone is known for its photochromic properties, but the structures of the initial and final forms have been the subject of a long debate. Analysis of the IR spectra recorded in low-temperature argon and xenon matrices, room-temperature solutions, and in the gas phase has allowed us to establish the nature of the photochromic species and of its precursor. Similar to the case of another beta-thioxoketone, monothiodibenzoylmethane, the photo-product has been assigned to the nonchelated SH exo-rotamer of the (Z)-enethiol tautomeric form, whereas the dominant ground-state species corresponds to the chelated (Z)-enol tautomeric form. Detailed vibrational assignments have been proposed for both forms based on quantum chemical calculations and polarization experiments. In the case of the chelated (Z)-enol species prevailing in the ground state, a second-order perturbative anharmonic analysis at the B3LYP/cc-pVTZ level indicated strong anharmonic effects associated with the intramolecular hydrogen bond, leading to a shift of more than 600 cm-1 of the wavenumber of the OH-stretching vibration. A small fraction of the SH endo-rotameric chelated (Z)-enethiol form was also detected under unperturbed conditions. The (Z)-enethiol form can be converted into the (Z)-enol form by irradiation at 290 nm.