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21.
Capillary zone electrophoresis tandem mass spectrometry detects low concentration host cell impurities in monoclonal antibodies
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Guijie Zhu Liangliang Sun Jennifer Heidbrink‐Thompson Srilatha Kuntumalla Hung‐yu Lin Christopher J. Larkin James B. McGivney IV Norman J. Dovichi 《Electrophoresis》2016,37(4):616-622
We have evaluated CZE‐ESI‐MS/MS for detection of trace amounts of host cell protein impurities in recombinant therapeutics. Compared to previously published procedures, we have optimized the buffer pH used in the formation of a pH junction to increase injection volume. We also prepared a 5‐point calibration curve by spiking 12 standard proteins into a solution of a human mAb. A custom CZE‐MS/MS system was used to analyze the tryptic digest of this mixture without depletion of the antibody. CZE generated a ~70‐min separation window (~90‐min total analysis duration) and ~300‐peak capacity. We also analyzed the sample using ultra‐performance LC‐MS/MS. CZE‐MS/MS generated approximately five times higher base peak intensity and more peptide identifications for low‐level spiked proteins. Both methods detected all proteins spiked at ~100 ppm level with respect to the antibody. 相似文献
22.
An Ghysels Benjamin T. Miller Frank C. Pickard IV Bernard R. Brooks 《Journal of computational chemistry》2012,33(28):2250-2275
Dimension reduction is often necessary when attempting to reach longer length and time scales in molecular simulations. It is realized by constraining degrees of freedom or by coarse‐graining the system. When evaluating the accuracy of a dimensional reduction, there is a practical challenge: the models yield vectors with different lengths, making a comparison by calculating their dot product impossible. This article investigates mapping procedures for normal mode analysis. We first review a horizontal mapping procedure for the reduced Hessian techniques, which projects out degrees of freedom. We then design a vertical mapping procedure for the “implosion” of the all‐atom (AA) Hessian to a coarse‐grained scale that is based upon vibrational subsystem analysis. This latter method derives both effective force constants and an effective kinetic tensor. Next, a series of metrics is presented for comparison across different scales, where special attention is given to proper mass‐weighting. The dimension‐dependent metrics, which require prior mapping for proper evaluation, are frequencies, overlap of normal mode vectors, probability similarity, Hessian similarity, collectivity of modes, and thermal fluctuations. The dimension‐independent metrics are shape derivatives, elastic modulus, vibrational free energy differences, heat capacity, and projection on a predefined basis set. The power of these metrics to distinguish between reasonable and unreasonable models is tested on a toy alpha helix system and a globular protein; both are represented at several scales: the AA scale, a Gō‐like model, a canonical elastic network model, and a network model with intentionally unphysical force constants. Published 2012 Wiley Periodicals, Inc. 相似文献
23.
We prove that there are compact submanifolds of the 3-sphere whose interiors are not homeomorphic to any geometric limit of hyperbolic knot complements. 相似文献
24.
Wongi Jang Richard Taylor IV Pascal N. Eyimegwu Prof. Hongsik Byun Prof. Jun-Hyun Kim 《Chemphyschem》2019,20(1):70-77
Composite materials consisting of nanoscale gold particles and protective polymer shells were designed and tested as catalysts in various chemical reactions. Initially, the systematic incorporation of multiple gold nanoparticles into a poly(N-isopropylacrylamide) particle was achieved by an in situ method under light irradiation. The degree of gold nanoparticle loading, along with the structural and morphological properties, was examined as a function of the amount of initial gold ions and reducing agent. As these gold nanoparticles were physically-embedded within the polymer particle in the absence of strong interfacial interactions between the gold nanoparticles and polymer matrix, the readily-accessible surface of the gold nanoparticles with a highly increased stability allowed for their use as recyclable catalysts in oxidation, reduction, and coupling reactions. Overall, the ability to integrate catalytically-active metal nanoparticles within polymer particles in situ allows for designing novel composite materials for multi-purpose catalytic systems. 相似文献
25.
A new phase in europium‐tin‐chalcogenide chemistry has been prepared using the reactive flux method: Eu8(Sn4Se14)(Se3)2. The compound crystallizes in the orthorhombic space group P21212 with cell parameters a = 11.990(2) Å, b = 16.425(4) Å, c = 8.543(1) Å, and Z = 2. Eu8(Sn4Se14)(Se3)2 is a three dimensional structure with EuII cations linked together with an unusual (Sn4Se14)12– anionic unit and (Se3)2– chains. UV‐VIS‐NIR band‐gap analysis shows that these black metallic crystals are likely semiconductors with an optical band‐gap of 1.07 eV. 相似文献
26.
Kai-Jie Chen John J. Perry IV Hayley S. Scott Qing-Yuan Yang Michael J. Zaworotko 《Chemical science》2015,6(8):4784-4789
Two isostructural metal–organic materials, Tripp-1-M (Tripp = 2,4,6-tris(4-pyridyl)pyridine; M = Co, Ni), that exhibit binodal 3,6-connected pyr network topology have been prepared and characterized. Tripp-1-M are based upon a novel M7F12
2+ cluster that possesses 12 connection points but, because of double cross-linking by 3-connected Tripp ligands, it functions as a 6-connected supermolecular building block (SBB). 相似文献
27.
The photophysical behaviors of the oligomer based on 1,1'-binaphthol with3,3'-acetylene spacer were investigated. The oligomer molecule has a naphthyl-acetylene-naphthyl effective conjugation segment. The atropic of the 1,1'-binaphthyl moiety led totwisted and rigid main chain in the oligomer. With the changes of the external environ-ment such as solvents used, solvent viscosity and ambient temperature, the wavelengthsof absorption and the intensities of fluorescence and absorption are changed slightly, butthe fluorescent intensity and quantum yield can be influenced. The luminescent behav-iors of the oligomer exhibit twisted intramolecular charge transfer characteristics, whichcould have a potential application in wavelength-stable light emitting material adaptableto ambient temperature and the solvents used in wide range. 相似文献
28.
Tuning Pore Size in Square‐Lattice Coordination Networks for Size‐Selective Sieving of CO2
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Dr. Kai‐Jie Chen Dr. David G. Madden Dr. Tony Pham Katherine A. Forrest Amrit Kumar Dr. Qing‐Yuan Yang Dr. Wei Xue Prof. Dr. Brian Space Dr. John J. Perry IV Prof. Dr. Jie‐Peng Zhang Prof. Dr. Xiao‐Ming Chen Prof. Dr. Michael J. Zaworotko 《Angewandte Chemie (International ed. in English)》2016,55(35):10268-10272
Porous materials capable of selectively capturing CO2 from flue‐gases or natural gas are of interest in terms of rising atmospheric CO2 levels and methane purification. Size‐exclusive sieving of CO2 over CH4 and N2 has rarely been achieved. Herein we show that a crystal engineering approach to tuning of pore‐size in a coordination network, [Cu(quinoline‐5‐carboxyate)2]n ( Qc‐5‐Cu ) ena+bles ultra‐high selectivity for CO2 over N2 (SCN≈40 000) and CH4 (SCM≈3300). Qc‐5‐Cu‐sql‐β , a narrow pore polymorph of the square lattice ( sql ) coordination network Qc‐5‐Cu‐sql‐α, adsorbs CO2 while excluding both CH4 and N2. Experimental measurements and molecular modeling validate and explain the performance. Qc‐5‐Cu‐sql‐β is stable to moisture and its separation performance is unaffected by humidity. 相似文献
29.
K. G. W. Inn E. Hall J. T. Woodward IV B. Stewart R. Pollanen L. Selvig S. Turner I. Outola S. Nour H. Kurosaki J. LaRosa M. Schultz Z. Lin Z. Yu C. McMahon 《Journal of Radioanalytical and Nuclear Chemistry》2008,276(2):385-390
Recoil ions from alpha-particle emission can contaminate surface-barrier detection systems. This contamination results in
increased measurement uncertainty, and may require the replacement of expensive detectors. Disposable thin Collodion films
are easily prepared and effectively retard the recoil ions when either directly applied to the surface of alpha-sources or
as catcher foils between the source and the detector. The thin films are particularly effective for relatively low-level sources,
but can sustain structural damage when exposed to high levels of recoil ions (tens of thousands per second) over extended
periods of time. 相似文献
30.
Ashley Ringer McDonald Jessica A. Nash Paul S. Nerenberg K. Aurelia Ball Olaseni Sode Jonathon J. Foley IV Theresa L. Windus T. Daniel Crawford 《International journal of quantum chemistry》2020,120(20):e26359
The Molecular Sciences Software Institute (MolSSI) is an National Science Foundation (NSF) funded institute that focuses on improving software, education, and training in the computational molecular sciences. Through a collaboration with the Molecular Education and Research Consortium in Undergraduate computational chemistRY (MERCURY), the MolSSI has developed resources for undergraduate and other early career students to lay an educational foundation for the next generation of computational molecular scientists. The resources focus on introducing best practices in software engineering to students from the very start to make their software more useable, maintainable, and reproducible. 相似文献