Raman Spectroscopic and SEM Analysis of Sodium-Zippeite

Raman at 298 and 77 K and infrared spectra of two samples of sodium-zippeite were studied and interpreted. U-O bond lengths in uranyl were calculated and compared with those inferred from the X-ray single crystal structure data of a synthetic sodium-zippeite analog. Hydrogen-bonding network in the studied samples is discussed. O-H…O bond lengths were calculated and compared with those predicted from the X-ray single crystal structure analysis

Molecular Structure of the Uranyl Mineral Zippeite - An XRD, SEM and Raman Spectroscopic Study

Raman spectra at 298 and 77 K and infrared spectra of the uranyl sulfate mineral zippeite, K2[(UO2)6(SO4)3O(OH)6]. 4 H2O, were studied. Observed bands were tentatively attributed to the (UO2)2+ and (SO4)2- stretching and bending vibrations, the OH stretching vibrations of water molecules and hydroxyls, H2O bending vibrations and libration modes, and ￤ U-OH bending vibrations. Empirical relations were used for calculation of U-O bond lengths in uranyl R = f(￮3 or ￮1 (UO2)2+) Å. This was found in agreement with U-O bond lengths from the single crystal structure analysis. The number of observed bands supports the conclusion from single crystal structure analysis that at least two symmetrically distinct U6+ (in uranyl) and S6+ (in sulfate), and water molecules and hydroxyls may be present in the zippeite crystal structure. Some O-H…O bond lengths were attributed to the hydrogen-bonding network in zippeite crystal structure

Raman Spectroscopy of Uranopilite of Different Origins - Implications for Molecular Structure

Uranopilite, \[(UO2)6(SO4)O2(OH)6(H2O)6](H2O)8, the composition of which may vary, can be understood as a complex hydrated uranyl oxy hydroxy sulfate. The structure of uranopilite of different localities has been studied by Raman spectroscopy at 298 and 77 K. A single intense band at 1009 cm-1 assigned to the ￮1 (SO4)2- symmetric stretching mode shifts to higher wavenumbers at 77 K. Three low intensity bands are observed at 1143, 1117 and 1097 cm-1. These bands are attributed to the (SO4)2- ν3 antisymmetric stretching modes. Multiple bands provide evidence that the symmetry of the sulphate anion in the uranopilite structure is lowered. Three bands are observed at 843 to 816 cm-1 in both 298 and 77 K spectra and are attributed to the ν1 symmetric stretching modes of the (UO2)2+ units. Multiple bands prove the symmetry reduction of the UO2 ion. Multiple OH stretching modes prove a complex arrangement of OH groupings and hydrogen bonding in the crystal structure. A series of infrared bands not observed in the Raman spectra are found at 1559, 1540, 1526 and 1511 cm-1 attributed to ￤ UOH bending modes. U-O bond lengths in uranyl and O-H…O bond lengths are calculated and compared with X-ray single crystal structure analysis. Raman spectra of uranopilites of different origin show subtle differences in spectra proving the spectra are origin and sample dependent. Hydrogen-bonding network and its arrangement in the crystal structure play an important role in the origin and stability of uranopilite

How Much Blood Is That? The Use of Scorecard Feedback to Improve Measurement of Blood Loss at Delivery

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Assessment of Financial Health of Selected Transport Companies Conducting Business in the Public Line Transport

As a part of their business, the transport companies provide the traffic services in the given region. For the needs of efficient managerial or financial management, it is necessary to know the detail financial analysis upon which the financial health of the company can be determined. The financial analysis utilizes the diagnostic methods which evaluates the company´s management from the viewpoint of the past, the presence and the expected future. Based on the financial health values, we can avoid future problems. The managers are warned against the possible bankruptcy in time. By selecting the appropriate classification models applied to the Czech environment, the financial situations of the carriers can be found out. Then, the intercompany comparison method is applied to assess the economic situation of selected carriers. The results achieved after applying the classification models and the intercompany comparison method serve as the key outcome of verification of credibility of selected classification models

The motor activity of DNA2 functions as an ssDNA translocase to promote DNA end resection

DNA2 nuclease–helicase functions in DNA replication and recombination. This requires the nuclease of DNA2, while, in contrast, the role of the helicase activity has been unclear. We now show that the motor activity of both recombinant yeast and human DNA2 promotes efficient degradation of long stretches of ssDNA, particularly in the presence of the replication protein A. This degradation is further stimulated by a direct interaction with a cognate RecQ family helicase, which functions with DNA2 in DNA end resection to initiate homologous recombination. Consequently, helicase- deficient yeast dna2 K1080E cells display reduced resection speed of HO-induced DNA double-strand breaks. These results support a model of DNA2 and the RecQ family helicase partner forming a bidirectional motor machine, where the RecQ family helicase is the lead helicase, and the motor of DNA2 functions as a ssDNA translocase to promote degradation of 5'-terminated DNA

Selective oxidation of bulky organic sulphides over layered titanosilicate catalysts

The authors acknowledge the Czech Science Foundation (P106/12/G015) for the financial support.Selective oxidation of sulphides is a straightforward method of preparation of organic sulphoxides and sulphones, which are important chemical intermediates and building blocks of pharmaceuticals and agrochemicals. Oxidation of methylphenyl sulphide (MPS), diphenyl sulphide (Ph2S), and dibenzothiophene (DBTH) over lamellar titanosilicate catalysts with the MFI and UTL-derived topology was investigated with hydrogen peroxide as the oxidant. Lamellar titanosilicates combine the advantages of crystalline zeolites and mesoporous molecular sieves due to accessible active sites located on the external surface of their layers. The selectivity of the MPS oxidation to methylphenyl sulphoxide is driven by the diffusion restrictions in the catalyst. A methylphenyl sulphoxide selectivity of 95% at 40% conversion was achieved using the Ti-IPC-1-PI catalyst together with an outstanding TONtot = 1418 after 30 min. The selectivity can be adjusted also by dosing of the oxidant to keep its concentration low during the reaction. The silica-titania pillared TS-1-PITi catalyst showed the highest potential of the tested catalysts in oxidative desulphuration, easily oxidising the DBTH to dibenzothiothene sulphone.PostprintPeer reviewe

Selective oxidation of bulky organic sulphides over layered titanosilicate catalysts

The authors acknowledge the Czech Science Foundation (P106/12/G015) for the financial support.Selective oxidation of sulphides is a straightforward method of preparation of organic sulphoxides and sulphones, which are important chemical intermediates and building blocks of pharmaceuticals and agrochemicals. Oxidation of methylphenyl sulphide (MPS), diphenyl sulphide (Ph2S), and dibenzothiophene (DBTH) over lamellar titanosilicate catalysts with the MFI and UTL-derived topology was investigated with hydrogen peroxide as the oxidant. Lamellar titanosilicates combine the advantages of crystalline zeolites and mesoporous molecular sieves due to accessible active sites located on the external surface of their layers. The selectivity of the MPS oxidation to methylphenyl sulphoxide is driven by the diffusion restrictions in the catalyst. A methylphenyl sulphoxide selectivity of 95% at 40% conversion was achieved using the Ti-IPC-1-PI catalyst together with an outstanding TONtot = 1418 after 30 min. The selectivity can be adjusted also by dosing of the oxidant to keep its concentration low during the reaction. The silica-titania pillared TS-1-PITi catalyst showed the highest potential of the tested catalysts in oxidative desulphuration, easily oxidising the DBTH to dibenzothiothene sulphone.PostprintPeer reviewe