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血液病与微量元素关系的研究 总被引:1,自引:0,他引:1
研究了血液病与微量元素的关系,发现再生障碍性贫血患者治疗前血清Cu升高(P〈0.05),缓解后Cu恢复正常。骨髓增生异常综合征(MDS)中RA+RAS组Cu及Cu/Zn比值高,Zn值降低不明显;RAEB+RAEB-T组Cu及Cu/Zn高,Zn值明显降低(P〈0.05)。急性白血病、淋巴瘤、多发性骨髓瘤及慢粒患者血清Cu、Zn及Cu/Zn比值与对照组比较均呈显著差异(P〈0.05 ̄0.01),而缓解 相似文献
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A microdialysis sampling (MDS) on‐line SPE (MDS/SPE) has been applied to redeem the detection after dilution to decrease matrix interference in the analysis of ketamine (K) and its two main metabolites, norketamine (NK) and dehydronorketamine (DHNK) in urine by HPLC. After being filtrated, diluted and adjusting the pH, K and its metabolites in the diluted sample solution were collected through MDS and then trapped on an on‐line SPE for HPLC analysis. The optimal conditions for MDS/SPE were investigated and then applied to real sample analysis. Experimental results indicated that the MDS/SPE by using regenerated cellulose hollow fiber (8‐cm length) and 1 mM sulfuric acid as the perfusate at 20 μL/min flow‐rate to collect analytes from 100‐fold diluted urine sample (20 mL at pH 6.0), and then having been trapped in octadecyl‐modified silica phase SPE for 30 min, offered the optimum efficiency. The concentration levels of 41, 42 and 28% (m/m) for K, NK and DHNK, respectively, in urine were redeemed for determination. The detection limits were 0.38, 0.33 and 0.34 ng/mL (in 100‐fold diluted sample) for K, NK and DHNK, respectively. The method provides a very simple, inexpensive and eco‐friendly procedure to determine K, NK and DHNK in urine. 相似文献
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Molecular dynamics simulations of cyclosporin A: The crystal structure and dynamic modelling of a structure in apolar solution based on NMR data 总被引:1,自引:0,他引:1
J. Lautz H. Kessler R. Kaptein W. F. van Gunsteren 《Journal of computer-aided molecular design》1987,1(3):219-241
Summary The conformation of the immunosuppressive drug cyclosporin A (CPA), both in apolar solution and in crystalline state, has been studied by computer simulation techniques. Three molecular dynamics (MD) simulations have been performed: one modelling the crystal structure and two modelling the structure in apolar solution, using a restrained MD approach in which data from nuclear magnetic resonance (NMR) and infrared (IR) spectroscopy are taken into account. The simulation of the crystalline state (MDC) concerns a system of 4 unit cells containing 16 cyclosporin A molecules and 22 water molecules, which is simulated using crystalline periodic boundary conditions. The simulations modelling the apolar solvent conformation (MDS) concern one isolated cyclosporin A molecule. In these simulations an extra term in the interatomic potential function is used, which forces the molecule to satisfy a set of 57 atom-atom distance constraints originating from nuclear Overhauser effects (NOEs) obtained from NMR spectroscopy and one distance constraint deduced from IR spectroscopy.From a comparison of the results of the crystal simulation to those of the X-ray experiment in terms of structure, atomic fluctuations, hydrogen bond pattern, etc., it is concluded that the force field that is used yields an adequate representation of crystalline cyclosporin A. Secondly, it is shown that the dynamic modelling technique that is used to obtain a structure in a polar solution from NMR distance information works well. Starting from initial conformations which have a root mean square difference of 0.14 nm both distance restrained MD simulations converge to the same final solution structure. A comparison of the crystal structure of cyclosporin A and the one in apolar solution shows that there are significant differences. The overall difference in atomic positions is 0.09 nm for the Cx atoms and 0.17 nm for all atoms. In apolar solution, the molecule is slightly more bent and the side chains of 1 MeBmt and 10 MeLeu adopt a different conformation.Abbreviations MeBmt
(4R)-4[(E)-2-butenyl]-4-methyl-l-Threonine
- MD
Molecular dynamics
- EM
Energy minimization
- MDC
Molecular dynamics simulation of the crystal
- MDS1
Restrained molecular dynamics simulation to obtain the structure in solution starting from the crystal structure
- MDS2
Like MDS1, but starting from the SMS structure
- SMS
Proposed structure in solution, obtained by model building
- XRAY
An X-ray structure
- CPA
Cyclosporin A
- NMR
Nuclear magnetic resonance spectroscopy
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NOE
Nuclear Overhauser enhancement
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MDS1
Mean simulated structure obtained by averaging over the time period 20–40 ps of the MDS1 simulation
- MDS2
Mean simulated structure obtained by averaging over the time period 10–30 ps of the MDS2 simulation
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Mean simulated structure obtained by averaging over the time period 7–15 ps and over the 16 asymmetric units in the computational box of the MDC simulation. 相似文献
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Pre-formulation studies constitute the first step of any pharmaceutical product development and manufacture. Establishment of a comprehensive library of critical physical, chemical, biological and mechanical properties of all materials used for a formulation can be costly, tedious and time consuming, despite its importance in quality manufacturing management. This study seeks to demonstrate the pharmaceutical application of multidimensional scaling (MDS) by incorporating it as a pre-formulation tool for grouping an expanded range of microcrystalline celluloses (MCC). MDS presents the various MCC grades in two-dimensional space based on their torque rheological properties; thus conferring an extra dimension to the pre-formulation tool to facilitate the visualization of the relative positions of each MCC grade. Through this work, the utility of MDS for expediting pre-formulation studies, in particular, grouping of excipients that are available in different brands and grades can be amply exemplified. 相似文献
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Phase Behavior of a Designed Cyclopropyl Analogue of Monoolein: Implications for Low‐Temperature Membrane Protein Crystallization
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Livia Salvati Manni Dr. Alexandru Zabara Dr. Yazmin M. Osornio Jendrik Schöppe Dr. Alexander Batyuk Prof. Dr. Andreas Plückthun Prof. Dr. Jay S. Siegel Prof. Dr. Raffaele Mezzenga Prof. Dr. Ehud M. Landau 《Angewandte Chemie (International ed. in English)》2015,54(3):1027-1031
Lipidic cubic phases (LCPs) are used in areas ranging from membrane biology to biodevices. Because some membrane proteins are notoriously unstable at room temperature, and available LCPs undergo transformation to lamellar phases at low temperatures, development of stable low‐temperature LCPs for biophysical studies of membrane proteins is called for. Monodihydrosterculin (MDS) is a designer lipid based on monoolein (MO) with a configurationally restricted cyclopropyl ring replacing the olefin. Small‐angle X‐ray scattering (SAXS) analyses revealed a phase diagram for MDS lacking the high‐temperature, highly curved reverse hexagonal phase typical for MO, and extending the cubic phase boundary to lower temperature, thereby establishing the relationship between lipid molecular structure and mesophase behavior. The use of MDS as a new material for LCP‐based membrane protein crystallization at low temperature was demonstrated by crystallizing bacteriorhodopsin at 20 °C as well as 4 °C. 相似文献
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Using the gradient-corrected BPW91 method and 6311++G(2d,2p) basis sets, it was found that adsorption of benzene by iron atoms forms a multiple-decker sandwich (MDS) geometry for the ground state (GS) of Fe(2)-(C(6)H(6))(3), as Fe(2) is broken. Though decoordination occurs, the ligands are bonded symmetrically to the Fe sites by η(6) (for the two external rings) and two η(3) (for the central ring) Fe-C coordinations; this big amount of Fe-C bonds enhances the stability of the MDS GS. This is unexpected, as the experiment suggests MDS for TM(n)-(C(6)H(6))(m) species of earlier transition metals (TMs) and clusters covered with benzene, i.e., rice-ball (RB) structures, for late 3d atoms. However, preserving Fe(2), an RB state was found, quasi-degenerate with the GS, with a smaller amount of Fe-C contacts and a stronger Fe(2) bond. The MDS shows higher stability for electron attachment and deletion events, but its adiabatic electron affinity, 1.11 eV, differs more from the experiment (0.80 ± 0.1 eV) than the one (0.97 eV) for RB. Thus, MDS and RB states can appear in a sample of Fe(2)-(C(6)H(6))(3). Like the electron affinity, the ionization energy of the complex is also smaller than those of the metal and benzene moieties, but closer to the former, signifying that the electron, delocalized through the 3d-π bonds, is mainly deleted from the metallic units. 相似文献
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对二苯胺-4-重氮盐(DS)、邻-甲氧基二苯胺-4-重氮盐(MDS)和N-甲基-间硝基二苯胺-4-重氮盐(NDS)及它们的重氮树脂(DR,MDR,NDR)在水溶液中的光,热分解研究表明,这些重氮盐和树脂的光分解性质,即感光灵敏性差别不大,而热分解性质,即热稳定性差别很大.MDS的热稳定性最好.固相膜中3种树脂的光分解亦差别不大,但N-甲基-间硝基二苯胺-4-重氮树脂(NDR)固相膜的热稳定性出乎预料地好.从疏水性的角度对NDR固相膜突出的热稳定性作了初步解释. 相似文献
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Bruce M. Allen Paul K. Predecki Maciej Kumosa 《Journal of computational chemistry》2014,35(9):756-764
Three open‐source applications, NanoEngineer‐1, packmol, and mis2lmp are integrated using an open‐source file format to quickly create molecular dynamics (MD) cells for simulation. The three software applications collectively make up the open‐source software (OSS) suite known as MD Studio (MDS). The software is validated through software engineering practices and is verified through simulation of the diglycidyl ether of bisphenol‐a and isophorone diamine (DGEBA/IPD) system. Multiple simulations are run using the MDS software to create MD cells, and the data generated are used to calculate density, bulk modulus, and glass transition temperature of the DGEBA/IPD system. Simulation results compare well with published experimental and numerical results. The MDS software prototype confirms that OSS applications can be analyzed against real‐world research requirements and integrated to create a new capability. © 2014 Wiley Periodicals, Inc. 相似文献
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《印度化学会志》2021,98(9):100102
Malarial infection due to P. falciparum is prominent cause in worldwide fatality. PfCRT, PfDHPS, PfMDR1 and PfDHFR1 play vital role as targets in malarial infection. We chose PfCRT-specific ligands for our study and tested them against all P. falciparum targets. The study was carried out by performing MDS and MD analyses with the NAMD and AutoDock softwares, respectively. The study's goal is to find potential ligands that can act on all malarial targets at various temperatures.The MDS studies revealed structural conformational changes and protein stability from normal human body temperature, 98.6 °F, to maximum human body temperature, 107 °F. This MDS analysis of Plasmodium targets was carried out by creating a graph of RMSD vs time. Further MD analysis revealed that the ligands reported against PfCRT also had a high binding energy against PfDHPS and PfDHFR. As a result, those ligands can also be targeted for Plasmodium falciparum proteins other than the three mentioned above. These ligands can be subjected to SAR and QSAR studies in order to develop novel molecules for malaria treatment. 相似文献
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This paper presents the experience gained by developers and users with implementation and operation of NorTRACKTM, a real-time computerized product tracking system. A Programmable Logic Controller (PLC) collects and transfers data in real time to NorTRACK’s OracleTM database on a Windows NTTM server network. After extensive development and Beta testing at MDS Nordion’s Canadian Irradiation Centre in Montreal, Canada, NorTRACK was installed in January 1997 with a new irradiation facility in Ethicon Endo-Surgery Inc.’s Albuquerque plant in the United States. NorTRACK communicates with the irradiator control and safety system, the plant's central manufacturing database, an innovative pallet staging and tote loading robot, and an automated dosimetry reading system. This integrated system allows the sterilization facility to monitor the irradiator operation and the flow of many products, through varied processing modes, continuously and reliably. As a result of operating with NorTRACK, both MDS Nordion’s CIC facility and the Endo-Surgery manufacturing site, are beginning to realize unique benefits in their respective operations. MDS Nordion is also initiating several future product enhancements and additional productivity modules. This paper describes the NorTRACK system, the various stages of the development project and Beta tests, and the experience of the users to date in their operations. 相似文献