检索结果-南通市图书馆

Syntheses of DL-threo-Thiamphenicol via Green Oxidation

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2006年第5期22卷 602-605页

作者： LIU Kai Robert Franzén yu Xiao-jing ZHAnG Jun XU You-jun School of Pharmaceutical Engineering Shenyang Pharmaceutical University Shenyang 110016 P. R. China Institute of Materials Chemistry Tampere University of Technology Korkeakoulunkatu 8 FIN-33720 Tampere Finland

Four methyl aryl thioethers related to thiamphenicol syntheses and methyl phenyl sulfide were cleanly oxidized into methyl sulfones in high to excellent yields via catalytic green oxidation with aqueous hydrogen peroxide in combination with sodium tungstate. When the same reactions were similarly performed in the absence of the catalyst, the corresponding sulfoxides could be obtained. This viable synthetic approach for the synthesis of DL-threo-thiamphenicol is a simple procedure, which has an economic advantage in view of its application for the large-scale synthesis because it can be carried out under mild conditions.

关键词： Green oxidation Hydrogen peroxide Sodium tungstate Thiamphenicol

Effect of Crystallization Conditions on Polymorphic Diversity of Malic Acid RS-Racemate

在线全文

学校读者我要写书评

暂无评论

Transactions of Tianjin University 2013年第2期19卷 86-91页

作者： Isakov A I Kotelnikova E n Kryuchkova L yu Lorenz H St.Petersburg State University St.Petersburg 199034Russia Max Planck Institute for Dynamics of Complex Technical Systems Magdeburg 39106Germany

Enantiomers （R （＋） and S（-））, RS-racemate mixture of enantiomers） of malic acid C4H605 have been （double compound） and （R ＋ S） -conglomerate （mechanical investigated by means of X-ray diffractometry and high tern- perature X-ray diffraction method. The RS-racemate was found to be able to form three polymorphic modifications, which we denominated as M1 （monoclinic, space group P21/c）, M2 （monoclinic, space group Cc）, and Tc （triclinic, space group P-l ）, the latter modification having been unknown before. Modification Tc was also described, and its X- ray diffraction characteristics, including interplanar spacings d, hkl indices, unit cell parameters, were defined. In addi- tion, X-ray diffraction characteristics for both reported earlier M1 and M2 monoclinic polymorphic modifications were measured with higher accuracy. The ability of RS-racemate to form one of the above three modifications （MI, M2, and Tc） or their mixtures containing various proportions and combinations of the components （M1 ＋ M2, M1 ＋ Tc, or M2 ＋ Tc） was found to depend on the type of crystallization medium （a melt, aqueous medium, ethanol or acetone solu- tion）, crystallization rate （from 2--3 minutes to 4 months）, and crystallization temperature. Heating S-enantiomer and M1 RS-racemate up to their respective melting points （100 ℃ and 124 ℃, correspondingly） only made them undergo thermal deformations, while heating （R ＋ S） -conglomerate in the temperature range of 96--110 ℃ resulted in its homogenization to form M2 RS-racemate, which, near the melting point （118 ℃）, namely, in the range of 112-116 ℃, was transformed into MI RS-racemate. Keywords： polvmorDhism; racemic, chiral

关键词： polymorphism racemic chiral

Collimated quasi-monochromatic beams of accelerated electrons in the interaction of a weak-contrast intense femtosecond laser pulse with a metal foil

在线全文

学校读者我要写书评

暂无评论

High Power Laser Science and Engineering 2013年第2期1卷 80-87页

作者： yu.A.Malkov A.n.Stepanov D.A.Yashunin L.P.Pugachev P.R.Levashov n.E.Andreev K.yu.Platonov A.A.Andreev Institute of Applied Physics Russian Academy of Sciences ul. Ulyanova 46 603950 Nizhny Novgorod Russia Joint Institute of High Temperatures Russian Academy of Sciences Izhorskaya ul. 13 125412 Moscow Russia Federal State Unitary Enterprise ‘‘Scientific and Industrial Corporation ‘Vavilov State Optical Institute’’’ Birzhevay liniya 12 St 199034 Petersburg Russia

We demonstrated experimentally the formation of monoenergetic beams of accelerated electrons by focusing femtosecond laser radiation with an intensity of 2×1017W/cm2onto the edge of an aluminum *** electrons had energy distributions peaking in the 0.2–0.8 MeV range with energy spread less than 20%.The acceleration mechanism related to the generation of a plasma wave as a result of self-modulation instability of a laser pulse in a dense plasma formed by a prepulse(arriving 12 ns before the main pulse)is ***-dimensional and two-dimensional Particle in Cell(PIC)simulations of the laser–plasma interaction showed that effective excitation of a plasma wave as well as trapping and acceleration of an electron beam with an energy on the order of 1 MeV may occur in the presence of sharp gradients in plasma density and in the temporal shape of the pulse.

关键词： acceleration of electrons femtosecond laser radiation plasma wave self-modulation instability

Synthetic morphogenesis:why reverse engineering should be prioritized

在线全文

学校读者我要写书评

暂无评论

Bio-Design and Manufacturing 2021年第2期4卷 429-431页

作者： V.n.nikolenko M.yu nikolayev M.Y.Sinelnikov Department of human anatomy first moscow state medical university(sechenov university)moscowrussian federation Department of normal and topographical anatomy lomonosov moscow state universitymoscowrussian federation Institute for regenerative medicine sechenov universitymoscowrussian federation

Dear Editor,In morphogenesis,the sequential execution of tissue arrangement depends on a vast array of signaling proteins and cellular *** mechanisms of such response have been identified:apoptosis,proliferation,fusion,adhesion,sorting,transition,folding,migration and *** combinations of these responses lead to the formation of various anatomical structures[1,2].

关键词： expansion. arrangement sorting

Preliminary Study of Photometric Redshifts Based on the Wide Field Survey Telescope

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2023年第12期23卷 138-152页

作者： yu Liu Xiao-Zhi Lin Yong-Quan Xue Huynh Anh n.Le CAS Key Laboratory for Research in Galaxies and Cosmology Department of AstronomyUniversity of Science and Technology of ChinaHefei 230026China School of Astronomy and Space Sciences University of Science and Technology of ChinaHefei 230026China

The Wide Field Survey Telescope(WFST)is a dedicated time-domain multi-band(u,g,r,i,and z)photometric survey facility under *** this paper,we present a preliminary study that assesses the quality of photometric redshifts based on WFST by utilizing mock observations derived with the galaxy catalog in the COSMOS/UltraVISTA *** apply the template fitting technique to estimate photometric redshifts by using the ZEBRA photometric-redshift code and adopting a modified set of adaptive *** evaluate the bias(median relative offset between the output photometric redshifts and input redshifts),normalized median absolute deviation(σ_(nMAD))and outlier fraction(f_(outlier))of photometric redshifts in two typical WFST observational cases,the single 30 s exposure observations(hereafter shallow mode)and co-added 50 minutes exposure observations(hereafter deep mode).We find bias≲0.006,σ_(nMAD)≲0.03,and f_(outlier)≲5%in the shallow mode and bias≈0.005,σ_(nMAD)≈0.06,and f_(outlier)≈17%–27%in the deep mode,respectively,under various lunar *** the WFST mock observational data with that from the upcoming CSST and Euclid surveys,we demonstrate that the zphot results can be significantly improved,with f_(outlier)≈1%andσ_(nMAD)≈0.02.

关键词： galaxies distances and redshifts-galaxies high-redshift-galaxies photometry

卡瑞利珠单抗治疗晚期转移性食管癌的临床疗效及安全性分析

在线全文

学校读者我要写书评

暂无评论

临床研究 2025年第1期33卷 65-68页

作者：俞强南阳豫西健和医院肿瘤内科河南南阳474500

目的探究转移性食管癌的晚期治疗中应用卡瑞利珠单抗的价值。方法选取南阳豫西健和医院2021年8月至2024年1月期间收入的64例转移性食管癌晚期患者,依据治疗方案的差异,将样本划分为对照组(n=32)采用常规化疗(紫杉醇+奈达铂)、而研究组(n... 详细信息

目的探究转移性食管癌的晚期治疗中应用卡瑞利珠单抗的价值。方法选取南阳豫西健和医院2021年8月至2024年1月期间收入的64例转移性食管癌晚期患者,依据治疗方案的差异,将样本划分为对照组(n=32)采用常规化疗(紫杉醇+奈达铂)、而研究组(n=32)在对照组治疗方法的基础上额外使用卡瑞利珠单抗治疗,3周为1个治疗周期,以上两组均治疗4个周期。分析两组临床疗效、免疫功能指标、免疫检查点情况、肿瘤标志物、日常生存质量及不良反应情况方面的差异。结果研究组疾病控制率高于对照组,差异具有统计学意义(P0.05),CD8^(+)T水平均低于治疗前,CD3^(+)T、CD4^(+)T/CD8^(+)T均高于治疗前,且研究组变化程度均高于对照组,差异均有统计学意义(P0.05)结论在常规化疗基础上联合应用卡瑞利珠单抗治疗转移性食管癌,能够改善患者免疫指标、免疫检查点、肿瘤标志物水平,显著提升疾病控制率,提高日常生存质量,保障用药安全性,具有临床应用意义。

关键词：卡瑞利珠单抗治疗晚期转移性食管癌临床疗效

Biochemical Factors Affecting the Quality of Products and the Technology of Processing Deep-Sea Fish, the Giant Grenadier Albatrossia pectoralis

在线全文

学校读者我要写书评

暂无评论

Journal of Ocean University of China 2020年第3期19卷 681-690页

作者： PIVnEnKO T.n. KARPEnKO yu.V. KRASHCHEnKO V.V. POZDnYAKOVA yu.M. ESIPEnKO R.V. Far Eastern State Technical Fisheries University Vladivostok 690087Russia

The composition of muscle tissues of a deep-sea species, the giant grenadier(Albatrossia pectoralis), and a mesopelagic species, the Alaska pollock(Theragra chalcogramma), are compared. Grenadier is proved to have a higher moisture content(91.7%) and lower protein(7.4%) and lipid(0.3%) contents. The factors responsible for the softening and moisture separation during processing of grenadier are identified. Contents of some fractions of non-protein nitrogenous components, including trimethylamine oxide(TMAO) and free amino acids, are clarified. The proportion of the main myofibrillar proteins myosin and actin, which is considered as an indicator of efficiency of structure formation in fish muscle tissue during processing, is almost 20% lower in giant grenadier than in pollock. The effects of endogenous protease, Са^2+-ATPase and transglutaminase on the processes of autolysis, denaturation, and possibility of myofibrillar proteins cross-linking were also studied. The proposed technology of getting a nutritionally balanced, gel-like, ready-to-use foodstuff from grenadier fillet includes its enrichment with pollock muscle tissue and supplementing with a binary structure-forming agent containing collagen and chitosan. nutritional value of the products is assessed by the method of biological assay and by determining the denaturation changes of myofibrillar proteins. The modes of fine mincing and thermal processing, as well as the shelf-life of the finished product are justified. The developed technology of producing a ready-to-eat food from giant grenadier will allow a more efficient use of this underutilized resource.

关键词： giant grenadier Alaska pollock myosin actin proteases ATPase transglutaminase softening structure formation ready-to-eat foodstuffs

Single DnA Condensation Induced by Hexammine Cobalt with Molecular Combing

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Physics 2012年第3期25卷 359-364,374页

作者： Gao-ming Hu yu Lin Shi-yong Ran Ya n-wei Wang Guang-can Yang College of Physics and Electronic Information Engineering Wenzhou University Wenzhou 325035 China

We investigated the interaction between DnA and hexammine cobalt III [Co（nH3）6]3＋ by a simple molecular combing method and dynamic light scattering. The average extension of A- DnA-YOYO-1 complex is found to be 20.9μm, about 30% longer than the contour length of the DnA in TE buffer （10 mmol/L Tris, 1 mmol/L EDTA, pH=8.0）, due to bis-intercalation of YOYO-1. A multivalent cation, hexammine cobalt, is used for DnA condensation. We find that the length of DnA-[Co（nH3）6]3＋ complexes decrease from 20.9 μm to 5.9μm as the concentration of the [Co（nH3）6]3＋ vary from 0 to 3 μmol/L. This observation provides a direct visualization of single DnA condensation induced by hexammine cobalt. The results from the molecular combing studies are supported by dynamic light scattering investigation, where the average hydrodynamic radius of the DnA complex decreases from 203.8 nm to 39.26 nm under the same conditions. It shows that the molecular combing method is feasible for quantitative conformation characterization of single bio-macromolecules.

关键词： Molecular combing Hexammine cobalt Condensation Dynamic light scatter-ing Fluorescent microscopy

Studies on unfolding energy spectra of neutrons using maximumlikelihood expectation–maximization method

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

nuclear Science and Techniques 2019年第9期30卷 24-33页

作者： Mehrdad Shahmohammadi Beni D.Krstic D.nikezic K.n.yu Department of Physics City University of Hong Kong Tat Chee Avenue Kowloon Tong Hong Kong China Faculty of Science University of Kragujevac Kragujevac Serbia State Key Laboratory of Marine Pollution City University of Hong Kong Tat Chee Avenue Kowloon Tong Hong Kong China

Energy spectra of neutrons are important for identification of unknown neutron sources and for determination of the equivalent dose. Although standard energy spectra of neutrons are available in some situations, e.g., for some radiotherapy treatment machines, they are unknown in other cases, e.g., for photoneutrons created in radiotherapy rooms and neutrons generated in nuclear reactors. In situations where neutron energy spectra need to be determined, unfolding the required neutron energy spectra using the Bonner sphere spectrometer (BSS) and nested neutron spectrometer (nnS) has been found promising. However, without any prior knowledge on the spectra, the unfolding process has remained a tedious task. In this work, a standalone numerical tool named ‘‘nRUunfold’’ was developed which could satisfactorily unfold neutron spectra for BSS or nnS, or any other systems using similar detection methodology. A generic and versatile algorithm based on maximum-likelihood expectation– maximization method was developed and benchmarked against the widely used STAY’SL algorithm which was based on the least squares method. The present method could output decent results in the absence of precisely calculated initial guess, although it was also remarked that employment of exceptionally bizarre initial spectra could lead to some unreasonable output spectra. The neutron count rates computed using the manufacturer’s response functions were used for sensitivity studies. The present nRUunfold code could be useful for neutron energy spectrum unfolding for BSS or nnS applications in the absence of a precisely calculated initial guess.

关键词： neutron spectrometry Maximum-likelihood expectation–maximization nested neutron spectrometer