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421.
Krauzy-Dziedzic K Ejfler J Szafert S Sobota P 《Dalton transactions (Cambridge, England : 2003)》2008,(19):2620-2626
Reactions of Ti(OiPr)4 or Zr(OEt)4 with 4 equivalents of 2,3-dihydro-2,2-dimethyl-7-benzofuranol (ddbfoH) in toluene gave neutral complexes that in the solid state are dimers of [Ti(micro-ddbfo)2(ddbfo)6] and [Zr(ddbfo)3(EtOH)(micro-EtO)]2 composition. The former could also be conveniently synthesized in a direct reaction of TiCl4 with ddbfoH. This air-stable aryloxo compound was found to initiate living ring-opening polymerization of lactides affording polyesters with narrow molecular weight distribution. It also catalyzed addition of terminal acetylenes to aryl aldehydes. 相似文献
422.
Brasuń J Cebrat M Sochacka A Gładysz O Swiatek-Kozłowska J 《Dalton transactions (Cambridge, England : 2003)》2008,(37):4978-4980
A new vasopressin analogue, [His(1,6)]AVP, was synthesized and characterized by potentiometric measurements as well as by UV-Vis, CD and EPR spectroscopy. At the physiological pH the peptide forms a stable complex with Cu(2+) ions which is characterized by the {NH(2), N(Im), N(Im(macrochelate))} binding mode. The replacement of both Cys by His residues in the vasopressin sequence results in a very significant increase in the efficiency of Cu(2+) binding. 相似文献
423.
Katarzyna Wykpis Jolanta Niedba?a Magdalena Popczyk Antoni Budniok Eugeniusz ?agiewka 《Russian Journal of Electrochemistry》2012,48(11):1123-1129
The Zn-Ni+Ni coatings were deposited under galvanostatic conditions at the current density range from 20 to 60 mA cm?2. The influence of deposition current density on surface morphology, chemical and phase composition and corrosion resistance of obtained coatings, was investigated. Structural investigations were conducted by X-ray diffraction method. Surface morphology and surface chemical composition of the obtained coatings were determined by a scanning electron microscope. Studies of electrochemical corrosion resistance were carried out in the 5% NaCl solution, using potentiodynamic and Scanning Kelvin Probe (SKP) methods. A possibility of incorporation of nickel powder from a suspension bath to the Zn-Ni matrix, during galvanostatic deposition was demonstrated. The results of chemical composition analysis show that the Zn-Ni + Ni coatings contain approximately 15?C18% at Ni. It was found that surface morphology, surface chemical and phase composition of Zn-Ni + Ni coatings depend in small degree on deposition current density. However, the current density influences distribution of nickel powder on the surface of these coatings. The optimal values of current density on account of corrosion resistance, are found to be j = 40?C50 mA cm?2. 相似文献
424.
The fundamental nature of reactivity in cytochrome P450 enzymes is currently controversial. Modelling of bacterial P450cam has suggested an important role for the haem propionates in the catalysis, though this finding has been questioned. Understanding the mechanisms of this enzyme family is important both in terms of basic biochemistry and potentially in the prediction of drug metabolism. We have modelled the hydroxylation of camphor by P450cam, using combined quantum mechanics/molecular mechanics (QM/MM) methods. A set of reaction pathways in the enzyme was determined. We were able to pinpoint the source of the discrepancies in the previous results. We show that when a correct ionization state is assigned to Asp297, no spin density appears on the haem propionates and the protein structure in this region remains preserved. These results indicate that the haem propionates are not involved in catalysis. 相似文献
425.
Michael Kirsch Priv.‐Doz. Peter Talbiersky Dipl.‐Chem. Jolanta Polkowska Dr. Frank Bastkowski Dr. Torsten Schaller Dr Herbert de Groot Prof. Dr. Dr. Frank‐Gerrit Klärner Prof. Dr. Thomas Schrader Prof. Dr. 《Angewandte Chemie (International ed. in English)》2009,48(16):2886-2890
Triple duty : A synthetic molecular clip traps nicotinamide adenine dinucleotide phosphate (NADP+; see picture) as well as occupying both the cofactor‐ and the substrate‐binding site in glucose‐6‐phosphate (G6P) dehydrogenase. This combination of two inhibition mechanisms makes the clip highly effective and selective for this enzyme over other dehydrogenases.
426.
Jolanta Sarowska Dorota Wojnicz Agnieszka Jama-Kmiecik Magdalena Frej-Mdrzak Irena Choroszy-Krl 《Molecules (Basel, Switzerland)》2021,26(15)
Human noroviruses, which belong to the enterovirus family, are one of the most common etiological agents of food-borne diseases. In recent years, intensive research has been carried out regarding the antiviral activity of plant metabolites that could be used for the preservation of fresh food, because they are safer for consumption when compared to synthetic chemicals. Plant preparations with proven antimicrobial activity differ in their chemical compositions, which significantly affects their biological activity. Our review aimed to present the results of research related to the characteristics, applicability, and mechanisms of the action of various plant-based preparations and metabolites against norovirus. New strategies to combat intestinal viruses are necessary, not only to ensure food safety and reduce infections in humans but also to lower the direct health costs associated with them. 相似文献
427.
Upscaling: Cell Symmetries and Scale Separation 总被引:1,自引:0,他引:1
428.
Krzysztof J. Kurzydłowski Małgorzata Lewandowska Wojciech Święszkowski Małgorzata Lewandowska-Szumieł 《Macromolecular Symposia》2007,253(1):1-9
Summary: Materials in general, to some degree are susceptible to environmental degradation. The degradation of biomaterials is one of the most relevant issues in the field of regenerative medicine. In industrial practice, the degradation is always a negative phenomenon. In bioengineering, the degradation may be undesirable (e.g. corrosion of metallic implants, wear of artificial joint implant) or desirable (biodegradable devices and tissue engineering). In both cases, the knowledge of the kinetics of degradation is crucial for safe use of biocomponents. The methods for predicting remaining life commonly used in industrial practice will be presented in the context of biomaterials. Non destructive techniques for monitoring degradation will be discussed and some ideas about their application to bio-environments proposed. 相似文献
429.
An attempt has been made for using MSA‐modified electrodes as linkage monolayers for electrostatic and covalent binding of cytochrome c (Cc). For MSA monolayers grown from an aqueous solution on Ag, attachment of Cc in its native state is proved in the case of covalent bonding. Electrostatic immobilization of Cc at pH 7 results in presence of at least some amount of Fe2+ high‐spin configuration and/or Fe3+ oxidation state. Native protein Fe2+ low‐spin state of Cc is observed after applying a negative potential to the Ag electrode. The influence of the solvent used for the preparation of the MSA monolayer and thiol surface coverage of the Ag surface was studied. It was shown that the key factor to obtain the native structure of Cc is the successful blocking of the metal surface by the MSA linking layer. IRRAS measurements of MSA on monocrystalline gold (111) at neutral pH confirm the successful electrostatic Cc immobilization, which preserves the Fe2+ oxidation state of the chromophore on this substrate. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
430.
Karolina Woziwodzka Jolanta Mayszko Ewa Koc-rawska Marcin rawski Paulina Dumnicka Artur Jurczyszyn Krzysztof Batko Paulina Mazur Magorzata Banaszkiewicz Marcin Krzanowski Paulina Goasa Jacek A. Mayszko Ryszard Drod Katarzyna Krzanowska 《Molecules (Basel, Switzerland)》2022,27(1)
Transgelin is a 22-kDa protein involved in cytoskeletal organization and expressed in smooth muscle tissue. According to animal studies, it is a potential mediator of kidney injury and fibrosis, and moreover, its role in tumorigenesis is emerging in a variety of cancers. The study included 126 ambulatory patients with multiple myeloma (MM). Serum transgelin-2 concentrations were measured by enzyme-linked immunoassay. We evaluated associations between baseline transgelin and kidney function (serum creatinine, estimated glomerular filtration rate—eGFR, urinary markers of tubular injury: cystatin-C, neutrophil gelatinase associated lipocalin—NGAL monomer, cell cycle arrest biomarkers IGFBP-7 and TIMP-2) and markers of MM burden. Baseline serum transgelin was also evaluated as a predictor of kidney function after a follow-up of 27 months from the start of the study. Significant correlations were detected between serum transgelin-2 and serum creatinine (R = 0.29; p = 0.001) and eGFR (R = −0.25; p = 0.007). Transgelin significantly correlated with serum free light chains lambda (R = 0.18; p = 0.047) and serum periostin (R = −0.22; p = 0.013), after exclusion of smoldering MM patients. Patients with decreasing eGFR had higher transgelin levels (median 106.6 versus 83.9 ng/mL), although the difference was marginally significant (p = 0.05). However, baseline transgelin positively correlated with serum creatinine after the follow-up period (R = 0.37; p < 0.001) and negatively correlated with eGFR after the follow-up period (R = −0.33; p < 0.001). Moreover, higher baseline serum transgelin (beta = −0.11 ± 0.05; p = 0.032) significantly predicted lower eGFR values after the follow-up period, irrespective of baseline eGFR and follow-up duration. Our study shows for the first time that elevated serum transgelin is negatively associated with glomerular filtration in MM and predicts a decline in renal function over long-term follow-up. 相似文献