Search results for "Selenium Compounds"
showing 9 items of 19 documents
A Method to Quantitatively Trap Volatilized Organoselenides for Stable Selenium Isotope Analysis
2011
If volatile organoselenides are to be analyzed for their stable Se isotope composition to elucidate sources and formation processes, organoselenides need to be trapped quantitatively to avoid artificial Se isotope fractionation. We developed an efficient trap of organoselenides to be used in microcosms designed to determine the Se isotope fractionation by microbial transformation of inorganic Se to volatile organoselenides. The recoveries of volatilized dimethyldiselenide (DMDSe) from aqueous standard solutions by activated charcoal and alkaline peroxide solution with subsequent freeze-drying and purification via a cation exchange resin were tested. Microcosm experiments with the Se-methyla…
Sensing Chiral Drugs by Using CdSe/ZnS Nanoparticles Capped withN-Acetyl-L-Cysteine Methyl Ester
2013
Chiral quantum dots (QDs), differing in their core or shell size and, consequently, in their optical properties, were synthesized by the treatment of commercially available amine-capped quantum dots with methyl ester N-acetyl-L-cysteine (CysP). Interestingly, their colloidal methanol solutions remain stable for several months. Their NMR and IR spectra were in accordance with CysP binding to the QD surface through two anchoring groups; its thiolate (strongly bound) and the carbonyl group of its ester (weaker bound) group, whereas their circular dichroism (CD) spectra showed a new broad redshifted band, suggesting that the attachment to the QD surface modified the conformational equilibrium t…
Bio serves nano: biological light-harvesting complex as energy donor for semiconductor quantum dots.
2012
Light-harvesting complex (LHCII) of the photosynthetic apparatus in plants is attached to type-II core-shell CdTe/CdSe/ZnS nanocrystals (quantum dots, QD) exhibiting an absorption band at 710 nm and carrying a dihydrolipoic acid coating for water solubility. LHCII stays functional upon binding to the QD surface and enhances the light utilization of the QDs significantly, similar to its light-harvesting function in photosynthesis. Electronic excitation energy transfer of about 50% efficiency is shown by donor (LHCII) fluorescence quenching as well as sensitized acceptor (QD) emission and corroborated by time-resolved fluorescence measurements. The energy transfer efficiency is commensurable …
Molecular structures of Se(SCH3)2 and Te(SCH3)2 using gas-phase electron diffraction and ab initio and DFT geometry optimisations
2005
The molecular structures of Se(SCH3)2 and Te(SCH3)2 were investigated using gas-phase electron diffraction (GED) and ab initio and DFT geometry optimisations. While parameters involving H atoms were refined using flexible restraints according to the SARACEN method, parameters that depended only on heavy atoms could be refined without restraints. The GED-determined geometric parameters (rh1) are: rSe-S 219.1(1), rS-C 183.2(1), rC-H 109.6(4) pm; S-Se-S 102.9(3), Se-S-C 100.6(2), S-C-H (mean) 107.4(5), S-Se-S-C 87.9(20), Se-S-C-H 178.8(19)° for Se(SCH3)2, and rTe-S 238.1(2), rS-C 184.1(3), rC-H 110.0(6) pm; S-Te-S 98.9(6), Te-S-C 99.7(4), S-C-H (mean) 109.2(9), S-Te-S-C 73.0(48), Te-S-C-H 180.…
Structural investigation of crystallized Ge-Ga-Se chalcogenide glasses
2018
H. Klym thanks to the Ministry of Education and Science of Ukraine for support and Dr. P. Demchenko for the assistance in XRD experiments.
Two Novel Ternary Dicopper(II) μ-Guanazole Complexes with Aromatic Amines Strongly Activated by Quantum Dots for DNA Cleavage
2013
Two novel (μ-guanazole)-bridged binuclear copper(II) complexes with 1,10-phenanthroline (phen) or 2,2'-bipyridine (bipy), [Cu2(μ-N2,N4-Hdatrz)(phen)2(H2O)(NO3)4] (1) and [Cu2(μ-N1,N2-datrz)2(μ-OH2)(bipy)2](ClO4)2 (2) (Hdatrz = 3,5-diamino-1,2,4-triazole = guanazole), have been prepared and characterized by X-ray diffraction, spectroscopy, and susceptibility measurements. Compounds 1 and 2 differ in the aromatic amine, which acts as a coligand, and in the Cu···Cu'-bridging system. Compound 1, which contains two mono-bridged copper ions, represents the first example of a discrete Cu-(NCN-trz)-Cu' complex. Compound 2, with two triply bridged copper ions, is one of the few compounds featuring a…
Animal Models of Stress - Current Knowledge and Potential Directions
2021
Finding new therapies and new antidepressant agents is of high clinical priority given that many cases of depressive disorder do not respond to conventional monoaminergic antidepressants such as selective serotonin reuptake inhibitors, tricyclic antidepressants, and monoamine oxidase inhibitors The authors demonstrated that electroacupuncture and fluoxetine, a second-generation antidepressant categorized as a selective serotonin reuptake inhibitor (Perez-Caballero et al , 2014), regulate the expression of key proteins in the calmodulin kinase (CAMK) signaling pathway, which are related to depression in the hippocampi of rats (Takemoto-Kimura et al , 2017;Xie et al , 2019) In a paper on “Sho…
Hypoxia-induced dysfunction of rat diaphragm
2004
Contains fulltext : 47331.pdf (Publisher’s version ) (Closed access) Oxidants may play a role in hypoxia-induced respiratory muscle dysfunction. In the present study we hypothesized that hypoxia-induced impairment in diaphragm contractility is associated with elevated peroxynitrite generation. In addition, we hypothesized that strenuous contractility of the diaphragm increases peroxynitrite formation. In vitro force-frequency relationship, isotonic fatigability, and nitrotyrosine levels were assessed under hypoxic (Po(2) approximately 6.5 kPa) and hyperoxic (Po(2) approximately 88.2 kPa) control conditions and also in the presence of authentic peroxynitrite (60 min), ebselen (60 min), and t…
Strategy for good dispersion of well-defined tetrapods in semiconducting polymer matrices.
2014
The morphology or dispersion control in inorganic/organic hybrid systems is studied, which consist of monodisperse CdSe tetrapods (TPs) with grafted semiconducting block copolymers with excess polymers of the same type. Tetrapod arm-length and amount of polymer loading are varied in order to find the ideal morphology for hybrid solar cells. Additionally, polymers without anchor groups are mixed with the TPs to study the effect of such anchor groups on the hybrid morphology. A numerical model is developed and Monte Carlo simulations to study the basis of compatibility or dispersibility of TPs in polymer matrices are performed. The simulations show that bare TPs tend to form clusters in the m…