Bielefeld University

About: Bielefeld University is a education organization based out in Bielefeld, Nordrhein-Westfalen, Germany. It is known for research contribution in the topics: Population & Quantum chromodynamics. The organization has 10123 authors who have published 26576 publications receiving 728250 citations. The organization is also known as: University of Bielefeld & UNIVERSITAET BIELEFELD.

Dynamical systems on translation bounded measures: Pure point dynamical and diffraction spectra

Abstract: Certain topological dynamical systems that arise from actions of -compact locally compact Abelian groups on compact spaces of translation bounded measures are considered. Such a measure dynamical system is shown to have a pure point dynamical spectrum if and only if its diffraction spectrum is pure point.

Substitution treatment of injecting opioid users for prevention of HIV infection

Abstract: BACKGROUND Injecting drug users are vulnerable to infection with HIV and other blood borne viruses as a result of collective use of injecting equipment as well as sexual behaviour. OBJECTIVES To assess the effect of oral substitution treatment for opioid dependent injecting drug users on rates of HIV infections, and high risk behaviours. SEARCH STRATEGY Multiple electronic databases were searched. Reference lists of retrieved studies, reviews and conference abstracts were handsearched. SELECTION CRITERIA Studies were required to consider the incidence of risk behaviours, or the incidence of HIV infection related to substitution treatment of opioid dependence. All types of original studies were considered. DATA COLLECTION AND ANALYSIS Each potentially relevant study was independently assessed by two reviewers. For studies that met the inclusion criteria, key information was extracted by one reviewer and confirmed by consultation between all four reviewers. MAIN RESULTS Twenty-eight studies, involving 7900 participants, were included. The majority were not randomised controlled studies. Issues of confounding and bias are discussed. The studies varied in several aspects limiting the extent of quantitative analysis. REVIEWERS' CONCLUSIONS Oral substitution treatment for opioid-dependent injecting drug users is associated with statistically significant reductions in illicit opioid use, injecting use and sharing of injecting equipment. It is also associated with reductions in the proportion of injecting drug users reporting multiple sex partners or exchanges of sex for drugs or money, but has little effect on condom use. It appears that the reductions in risk behaviours related to drug use do translate into reductions in cases of HIV infection. The lack of data from randomised controlled studies limits the strength of the evidence presented in this review. However, these findings add to the stronger evidence of effectiveness of substitution treatment on drug use, and treatment retention outcomes shown by other systematic reviews. On this basis, the provision of substitution treatment for opioid dependence in countries with emerging HIV and injecting drug use problems as well as in countries with established populations of injecting drug users should be supported.

Catalytic oxidation of VOCs over mixed Co-Mn oxides

Abstract: This work reports the synthesis and characterization of single-phase cobalt manganese oxide (CMO) spinels Co3−xMnxO4 (0 ≤ x ≤ 0.34) prepared by the pulsed-spray evaporation chemical vapor deposition (PSE–CVD) method. Structure and cationic distribution of the obtained films were characterized by XRD, FTIR, XPS and Raman spectroscopy. Temperature-programmed reduction/re-oxidation (TPR/TPO) was used to elucidate the redox properties of the deposited films. The electrical resistivity was measured in the temperature range of 27–450 °C. XRD, FTIR and Raman spectra reveal the formation of single-phase cubic spinel structures up to x = 0.34. With the substitution of cobalt cations with Mn3+ and Mn4+ ions, the unit cell of the cubic spinel shows a linear increase; the TPR results indicate a lower reducibility while the TPO results display no evident change; also, the ratio Co3+/Co2+ decreased and both electrical resistivity and thermal stability showed increasing trends. The observed behavior is attributed to the progressive incorporation of manganese, which induces structural defects favoring the formation of anionic vacancies and the restriction of the oxygen mobility. The catalytic activities of the doped spinels were investigated for the deep oxidation of unsaturated hydrocarbons (C2H2 and C3H6). The introduction of a slight amount of manganese shifted the light-off curves toward lower temperatures. Based on the XPS results, the enhanced catalytic activity is thought to benefit from the abundant presence of oxygen vacancies in the doped oxide.