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941.
Dr. Baptiste Joalland Nuwandi M. Ariyasingha Hassan R. Younes Shiraz Nantogma Dr. Oleg G. Salnikov Dr. Nikita V. Chukanov Dr. Kirill V. Kovtunov Prof. Igor V. Koptyug Prof. Juri G. Gelovani Prof. Eduard Y. Chekmenev 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(8):2774-2781
Many MRI contrast agents formed with the parahydrogen-induced polarization (PHIP) technique exhibit biocompatible profiles. In the context of respiratory imaging with inhalable molecular contrast agents, the development of nonflammable contrast agents would nonetheless be highly beneficial for the biomedical translation of this sensitive, high-throughput and affordable hyperpolarization technique. To this end, we assess the hydrogenation kinetics, the polarization levels and the lifetimes of PHIP hyperpolarized products (acids, ethers and esters) at various degrees of fluorine substitution. The results highlight important trends as a function of molecular structure that are instrumental for the design of new, safe contrast agents for in vivo imaging applications of the PHIP technique, with an emphasis on the highly volatile group of ethers used as inhalable anesthetics. 相似文献
942.
Dr. Esther Frederick Dr. Quinn Campbell Dr. Igor V. Kolesnichenko Dr. Luis F. Peña Dr. Angelica Benavidez Dr. Evan M. Anderson Dr. David R. Wheeler Dr. Shashank Misra 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(53):13337-13341
Ultradoping introduces unprecedented dopant levels into Si, which transforms its electronic behavior and enables its use as a next-generation electronic material. Commercialization of ultradoping is currently limited by gas-phase ultra-high vacuum requirements. Solvothermal chemistry is amenable to scale-up. However, an integral part of ultradoping is a direct chemical bond between dopants and Si, and solvothermal dopant-Si surface reactions are not well-developed. This work provides the first quantified demonstration of achieving ultradoping concentrations of boron (∼1e14 cm2) by using a solvothermal process. Surface characterizations indicate the catalyst cross-reacted, which led to multiple surface products and caused ambiguity in experimental confirmation of direct surface attachment. Density functional theory computations elucidate that the reaction results in direct B−Si surface bonds. This proof-of-principle work lays groundwork for emerging solvothermal ultradoping processes. 相似文献
943.
Chernyakova Katsiaryna Vrublevsky Igor Jagminas Arunas Klimas Vaclovas 《Journal of Solid State Electrochemistry》2021,25(4):1453-1460
Journal of Solid State Electrochemistry - The purpose of this work was to study and analyze the effect of electrolyte temperature and anodization voltage on cell morphology of thin films of... 相似文献
944.
This review summarises the high potential of immobilised cells systems for the fermentative production of compounds, mainly produced by representatives of the Clostridium genus. Microorganisms of Clostridium species are recognised as good producers of a wide range of chemicals in almost every sector of industry. The combination of this microorganism with its immobilisation opens up new possibilities and renders the fermentation process more sophisticated than in a free-cell system. This review provides a comprehensive summary of techniques used in immobilisation of Clostridium species with regard to specific products and types of fermentation. In addition, comparisons of particular types of immobilisation techniques used in fermentation processes are summarised by specific products. 相似文献
945.
946.
Gisele Luiza Pavan Igor Tadeu Lazzarotto Bresolin Aline Ferreira Velho Muzio Daniele Celestino Cunha Sonia Maria Alves Bueno 《Biomedical chromatography : BMC》2019,33(1)
The behavior of human immunoglobulin G (IgG) and antigen‐binding fragment (Fab fragment) adsorption onto phospho‐l ‐tyrosine immobilized on agarose (P‐Tyr‐agarose) was evaluated by pseudoaffinity chromatography. The effects of buffer systems MES, MOPS, Bis–Tris, Tris–HCl and sodium phosphate (NaP) and pH on IgG adsorption were studied and high purity values were obtained (96%, based on ELISA analysis of albumin, transferrin and immunoglobulins A, G and M) when IgG was purified from human plasma diluted in 10 mmol L?1 NaP buffer at pH 6.0. The capture of IgG by the P‐Tyr‐agarose was also promising, since 91% of the IgG was adsorbed when plasma was diluted in 25 mmol L?1 MES buffer at pH 5.5, recommending its use for IgG depletion from human plasma under this condition. The experimental data on IgG adsorption kinetics were in agreement with the pseudo‐second‐order model. The adsorption isotherm data were well described by the Langmuir–Freundlich model with the value of parameter n being <1 (0.72), indicating negative cooperativity. Selectivity was achieved on P‐Tyr‐agarose from digested human IgG in HEPES 25 mmol L?1 buffer at pH 7.0 where Fab fragments were obtained in eluted fractions without Fc fragments (but with uncleaved IgG) with 86.2% recovery. 相似文献
947.
Igor E. Pritsker 《Journal of Mathematical Sciences》2012,183(6):810-822
We study several related problems on polynomials with integer coefficients. This includes the integer Chebyshev problem, and the Schur problems on means of algebraic numbers. We also discuss interesting applications to the approximation by polynomials with integer coefficients, and to the growth of coefficients for polynomials with roots located in prescribed sets. The distribution of zeros for polynomials with integer coefficients plays an important role in all of these problems. 相似文献
948.
Wenping Guo Anan Wu Igor Ying Zhang Xin Xu 《Journal of computational chemistry》2012,33(27):2142-2160
Calculation of large complex systems remains to be a great challenge, where there is always a trade‐off between accuracy and efficiency. Recently, we proposed the extended our own n‐layered integrated molecular orbital (ONIOM) method (XO) (Guo, Wu, Xu, Chem. Phys. Lett. 2010 , 498, 203) which surmounts some inherited limitations of the popular ONIOM method by introducing the inclusion‐exclusion principle used in the fragmentation methods. The present work sets up general guidelines for the construction of a good XO scheme. In particular, force‐error test is proposed to quantitatively validate the usefulness of an XO scheme, taking accuracy, efficiency and scalability all into account. Representative studies on zeolites, polypeptides and cyclodextrins have been carried out to demonstrate how to strive for high accuracy without sacrificing efficiency. As a natural extension, XO is applied to calculate the total energy, fully optimized geometry and vibrational spectra of the whole system, where ONIOM becomes inapplicable. © 2012 Wiley Periodicals, Inc. 相似文献
949.
The innovative radiating structures as a conical millimeter wave FZP lens are proposed for subwavelength focusing.The results of FDTD simulation and experimental verification are discussed.It has been shown that in contrast to the flat diffractive optics the curvilinear 3D diffractive conical optics is capable of overcoming 3D Abbe barrier with a focal distance F greater than 2λ.The focal intensity distribution for such type of lenses is not circularly symmetric and thus the focal spot in the high numerical aperture case is no longer an Airy pattern.These results may find useful applications in optical microscopes,including"reverse-microscope",nondestructive testing,microoptics,and nanooptics. 相似文献
950.