Two subforms of eukaryotic topoisomerase I Purification and structure-function relationships

AbstractA new method for isolation of eukaryotic topoisomerase 1 from calf thymus and from Jurkat-1 cells using HPLC has been developed. The method allows quantitative purification of high molecular weight topo I and of two low molecular weight fractions differing by their isoelectric points. It has been suggested that these fractions be characterized as two subforms of the enzyme possessing structural and functional differences. The differences in their specific activities, sensitivity to camptothecin and in their proteolytic digestion maps have been demonstrated for the two enzymes

Design, Performance, and Calibration of CMS Hadron Endcap Calorimeters

Detailed measurements have been made with the CMS hadron calorimeter endcaps (HE) in response to beams of muons, electrons, and pions. Readout of HE with custom electronics and hybrid photodiodes (HPDs) shows no change of performance compared to readout with commercial electronics and photomultipliers. When combined with lead-tungstenate crystals, an energy resolution of 8\% is achieved with 300 GeV/c pions. A laser calibration system is used to set the timing and monitor operation of the complete electronics chain. Data taken with radioactive sources in comparison with test beam pions provides an absolute initial calibration of HE to approximately 4\% to 5\%

CMS physics technical design report : Addendum on high density QCD with heavy ions

Peer reviewe

μ-Diborolyl triple-decker complexes with carbonyl ligands: Synthesis, structures and electrochemistry

Triple-decker complexes with a bridging diborolyl ligand CpCo(m-1,3-C3B2Me5)M(CO)3 (M = Mn, 2; Re, 3), CpCo(m-1,3-C3B2Me5)Ru(CO)2Cl (4) and CpCo(m-1,3-C3B2Me5)Ru(CO)(m-CO)2Ru(CO)Cp (5) were synthesized by reaction of the sandwich anion [CpCo(1,3-C3B2Me5)]e (1) with [(naphthalene)Mn(CO)3]þ, [Re(CO)3(THF)2Br]2, or [Ru(CO)3Cl2]2. Structures of 4 and 5 were determined by X-ray diffraction. The spectroelectrochemical behaviour of compounds 2 and 3 was studied. IR-spectroscopical and computational data suggest that anion 1 is significantly stronger donor than Cp but slightly weaker than Cp*

Разработка технологии изготовления детали «Колесо зубчатое»

Зубчатые колеса широко применяются в машиностроительной отрасли, благодаря ним осуществляется изменение усилий передаваемое от исполнительных механизмов. Разработка технологического процесса изготовления детали - важная составляющая часть производственного процесса. Обеспечение производительности при разработке технологии невозможно осуществить без решения ряда задач, к которым относятся: выбор методов обработки поверхностей; выбор технологических баз; расчеты минимальных припусков, режимов резания; выбор оборудования и технологической оснастки, режущего инструмента и нормирование операций технологического процесса. В данной работе рассматриваются и решаются все поставленные задачи.Gear wheels are widely used in the engineering industry, thanks to them, a change in the forces transmitted from the actuators is carried out. The development of a technological process for manufacturing a part is an important part of the production process. Provision of productivity in the development of technology cannot be carried out without solving a number of problems, which include: selection of surface treatment methods; selection of technological bases; calculations of minimum allowances, cutting conditions; selection of equipment and technological equipment, cutting tools and standardization of technological process operations. In this work, all the tasks are considered and solved

Thioether Iron Complexes [(X-SMe-7,8-C2B9H10)Fe(C6H6)] (X = 9 or 10) as Synthons of Neutral Ferracarborane Fragments

The demethylation reactions of the cyclohexadienyl complexes [(η-X-SMe2-7,8-C2B9H10)Fe(η5-C6H7)] X = 9 (1a), 10 (1b); X is the number of the substituent position with PhCH2SNa in N,N-dimethylformamide (DMF) and subsequent protonation by acetic acid lead to the ironâ\u80\u93benzene complexes [(η-X-SMe-7,8-C2B9H10)Fe(η-C6H6)] (2a and 2b). The visible-light irradiation of 2a in the presence of tBuNC or [Cp*Fe(η-cyclo-P5)] (Cp* = pentamethylcyclopentadienyl) affords the neutral half-sandwich complex [(η-9-SMe-7,8-C2B9H10)Fe(tBuNC)3] (3) or the triple-decker complex [(η-9-SMe-7,8-C2B9H10)Fe(µ-η:η-cyclo-P5)FeCp*] (4). The reaction of 2b with (THF)W(CO)5(THF = tetrahydrofuran) selectively gives the ironâ\u80\u93tungsten dinuclear complex [(η-10-SMeW(CO)5-7,8-C2B9H10)Fe(η-C6H6)] (5). The structures of 2a, 4, and 5 were determined by X-ray diffraction. Electrochemistry revealed that the redox processes of the SMe-substituted ferracarboranes are cathodically shifted (by ca. 350 mV) with respect to the corresponding redox changes of the SMe2analogs. The Feâ\u80\u93C6H6bonding in 2a and the related benzene complexes [(η-9-SMe2-7,8-C2B9H10)Fe(η-C6H6)]+and [(η-7,8-C2B9H11)Fe(η-C6H6)] was analyzed by energy-decomposition analysis

Synthesis of 13-vertex dimetallacarboranes by electrophilic insertion into 12-vertex ruthenacarboranes

The electrophilic insertion of organometallic species into metallacarboranes was studied in detail for the model compound-the 12-vertex closo-ruthenacarborane anion [Cp∗Ru(C2B9H11)]- (1). Reactions of the anion 1 with the 12-electron cationic species [M(ring)]+ (M(ring) = RuCp, RuCp∗ and Co(C4Me4)) gave the 13-vertex closo-dimetallacarboranes Cp∗Ru(C2B9H11)M(ring). Similar reactions of the neutral ruthenacarborane Cp∗Ru(Me2S-C2B9H10) produce the cationic dimetallacarboranes [Cp∗Ru(Me2S-C2B9H10)M(ring)]+. The symmetrical 13-vertex diruthenacarboranes (C5R5)Ru(R2C2B9H9)Ru(C5R5) can be prepared by the direct reactions of Tl2[7,8-R2-7,8-C2B9H9] (R = H and Me) with two equivalents of [CpRu(MeCN)3]+ or [Cp∗RuCl]4. The insertions of the 14-electron cationic species [M(ring)]+ (M(ring) = NiCp, NiCp∗ and Co(C6Me6)) into 1 gave the 13-vertex dimetallacarboranes Cp∗Ru(C2B9H11)M(ring), which have a distorted framework with one open face. The structures of Cp∗Ru(C2B9H11)Co(C4Me4) and Cp∗Ru(C2B9H11)NiCp were established by X-ray diffraction. Some of the 13-vertex dimetallacarboranes have two electrons less than required by Wade's rules. This violation is explained by the absence of the appropriate pathway for the distortion of the framework