Search results for "XAS"
showing 10 items of 49 documents
Understanding the Conversion Process of Magnetron-Deposited Thin Films of Amorphous ReO$_x$ to Crystalline ReO$_3$ upon Thermal Annealing
2020
Crystal growth & design 20(9), 6147 - 6156 (2020). doi:10.1021/acs.cgd.0c00848
Hetero-Telechelic Dye-Labeled Polymer for Nanoparticle Decoration
2009
The synthesis of poly(methyl methacrylate) (PMMA) exhibiting one fluorescent dye (Texas Red) and one methyl disulfide end group is described. It is shown that the latter end group enabled the exchange of both oleic amine on gold nanoparticles (AuNP) and of oleic acid on CdSe/ZnS quantum dots (QD), allowing for a phase transfer of both types of nanoparticles (NP) from hexane into dimethylformamide due to the solubility provided by the PMMA chains. For AuNP, a fluorescence quenching of the dye was found due to fluorescence resonance energy transfer (FRET) from the dye to the AuNP, while QDs caused a fluorescence enhancement by FRET from the QD to the attached dyes. Due to the hetero-telecheli…
Hazardous air pollutants and primary liver cancer in Texas.
2016
The incidence of hepatocellular carcinoma (HCC), the most common primary liver cancer, is increasing in the US and tripled during the past two decades. The reasons for such phenomenon remain poorly understood. Texas is among continental states with the highest incidence of liver cancer with an annual increment of 5.7%. Established risk factors for HCC include Hepatitis B and C (HBV, HCV) viral infection, alcohol, tobacco and suspected risk factors include obesity and diabetes. While distribution of these risk factors in the state of Texas is similar to the national data and homogeneous, the incidence of HCC in this state is exceptionally higher than the national average and appears to be di…
Comparative Experimental and Theoretical Study of the Fe L-2,L-3-Edges X-ray Absorption Spectroscopy in Three Highly Popular, Low-Spin Organoiron Com…
2019
The occupied and unoccupied electronic structures of three highly popular, closed shell organoiron complexes ([Fe(CO)(5)], [(eta(5)-C5H5 )Fe(CO)(mu-CO)](2), and [(eta(5)-C5H5)(2)Fe]) have been theoretically investigated by taking advantage of density functional theory (DFT) calculations coupled to the isolobal analogy (Elian et al. Inorg. Chem. 1976, 15, 1148). The adopted approach allowed us to look into the relative role played by the ligand -> Fe donation and the Fe -> ligand back-donation in title molecules, as well as to investigate how CO- (terminal or bridging) and [(eta(5)-C5H5)](-)-based pi* orbitals compete when these two ligands are simultaneously present as in [(eta(5)-C5H…
cis-[(η5-C5H5)Fe(η1-CO)(μ-CO)]2, the poor relative betweencisandtranstautomers. A theoretical study of the gas-phase Fe L3-edge and C and O K-edge XA…
2021
The relative stability oftrans-[(η5-C5H5)Fe(η1-CO)(μ-CO)]2(trans-I) andcis-Itautomers in a vacuum and in solvents with different dielectric constants (ε) has been investigated by exploiting density functional theory (DFT). Theoretical results indicate that, in agreement with experimental evidence,trans-Iis more stable thancis-Iin a vacuum (∼1.5 kcal mol−1;ε= 1), while the opposite is true in media withε> 7. Differently from solution, DFT outcomes pertaining to the vapor-phasecis-I⇆trans-Iequilibrium at T = 368 K, the temperature at which the Fe L2,3-edges and the C and O K-edge X-ray absorption spectroscopy (XAS) data ofIhave been recorded, ultimately indicate thetrans-Ipredominance (∼93…
Behavioral and Chemical Investigations of Contact Kairomones Released by the Mud Dauber Wasp Trypoxylon politum, a Host of the Parasitoid Melittobia …
2011
Contact kairomones from the host mud dauber wasp Trypoxylon politum Say (Hymenoptera: Crabronidae) that mediate behavioral responses of its ectoparasitoid Melittobia digitata Dahms (Hymenoptera: Eulophidae) were investigated. Chemical residues from host by-products, the cocoon, and the meconium, induced arrestment behavior of macropterous female parasitoids, while those from the host stage attacked, i.e., the prepupa, did not. Melittobia digitata response to polar and apolar extracts of host by-products indicated kairomone(s) solubility mainly in hexane. GC and GC/MS analysis of cocoon and meconium apolar extracts revealed a mixture of linear carboxylic acids from C(6) to C(18), and both ex…
Rickettsia typhi and Haemophagocytic Syndrome
2017
Appropriate therapy (dexamethasone, cyclosporin, and etoposide) could save the patient in those cases in which the pathogen-direct therapy has not been sufficient by itself to control the disease.
The complementary structural studies of the double metal cyanide type catalysts for the ring opening polymerization of the oxiranes
2016
Przeprowadzono badania strukturalne katalizatorów dimetalocyjankowych (DMC) z dwoma rodzajami ligandów organicznych. Zaproponowano wyjaśnienie etapów przebiegu krzywych otrzymanych metodą analizy termograwimetrycznej i różnicowej kalorymetrii skaningowej (TG/DSC) badanych katalizatorów. Wykazano obecność kilku stopni związania ligandów w kompleksach DMC. Na podstawie wyników badań z wykorzystaniem absorpcji rentgenowskiej (XAS) stwierdzono, że centrum aktywne katalizatora stanowi atom cynku. W bezpośrednim sąsiedztwie atomów Zn wykryto obecność atomów Cl, natomiast w najbliższych sferach koordynacyjnych atomu Zn nie wykryto atomów tlenu.
Hard X-ray resonant electronic spectroscopy in transition metal oxides
2005
K-edge X-ray absorption and 2p-XPS spectra of 3d-element oxides present spectral features which cannot be explained within a simple one-electron model. These features reveal the fine electronic structure of transition metal (TM) oxides valence states resulting from hybridized TM-3d and O-2p states, and the correlations between these valence electrons. In this paper, we show how resonant electronic spectroscopy (resonant Auger or resonant photoelectron spectroscopy) around the TM K-edge can be used to interpret the structures of the threshold and, with the help of theoretical calculation, to determine the electronic configuration of the excited ion. Quadrupolar transitions towards localized …
Coprology of Panthera tigris altaica and Felis bengalensis euptilurus from the Russian Far East
2007
Fecal samples from the Siberian tiger (Panthera tigris altaica) and the Amur cat (Felis bengalensis euptilurus) from Far Eastern Russia, were examined for parasites. A natural sedimentation methodology was used and a complete examination of all the sediment was performed. This fecal investigation allowed us to isolate and identify several developmental stages of gastrointestinal, hepatic, and respiratory parasites. Five parasites were found from P. t. altaica: 11 trematodes (Platynosomum fastosum) and 4 nematodes (Strongyloides sp., Ancylostomatidae, Toxascaris leonina, and Toxocara cati). Five parasites were found from F. b. euptilurus: 1 cestode (Diplopylidium sp.) and 4 nematodes (Trichu…