Analysis of Phytoestrogens by High Performance Liquid Chromatography

Phytoestrogens are biochemicals synthesized in plants which mimic steroidal estrogen activity in mammals. Analysis of these compounds in the legumes which produce them and in body fluids is important to the study of their physiological effects. High pressure liquid chromatography (HPLC) has been found to be an efficient and sensitive method of identification and quantitation of isoflavonoids, one class of phytoestrogen. Here we report the separation of three isoflavonoids, biochanin A, genistein and daidzein using an HPLC system with a Cg reverse phase column and a linear gradient mobile phase containing acetonitrile and acetic acid/water (10/90, v/v) over 60 minutes. Minimum detection limits for the three isoflavonoids were 0.556 mug/mL, 0.314 mug/mL, and 0.377 mug/mL, respectively. This method was used to measure the concentrations of isoflavonoids in two types of soy meal and in several animal feeds. Projected use of this assay includes studies of reproductive ability following ingestion of these isoflavonoids in domestic ruminants and in wild rodents

A kinetic Monte Carlo study of desorption of H2 from graphite (0001)

The formation of H2 in the interstellar medium proceeds on the surfaces of silicate or carbonaceous particles. To get a deeper insight of its formation on the latter substrate, this letter focuses on H2 desorption from graphite (0001) in Temperature-Programmed-Desorption Monte-Carlo simulations. The results are compared to experimental results which show two main peaks and an intermediate shoulder for high initial coverage. The simulation program includes barriers obtained by ab-initio methods and is further optimised to match two independent experimental observations. The simulations reproduce the two experimental observed desorption peaks. Additionally, a possible origin of the intermediate peak is given.Comment: 9 pages, 5 figures, Chem. Phys. Lett. in pres

Formation of Mobile Chromatin-Associated Nuclear Foci Containing HIV-1 Vpr and VPRBP Is Critical for the Induction of G2 Cell Cycle Arrest

HIV-1 Viral protein R (Vpr) induces a cell cycle arrest at the G2/M phase by activating the ATR DNA damage/stress checkpoint. Recently, we and several other groups showed that Vpr performs this activity by recruiting the DDB1-CUL4A (VPRBP) E3 ubiquitin ligase. While recruitment of this E3 ubiquitin ligase complex has been shown to be required for G2 arrest, the subcellular compartment where this complex forms and functionally acts is unknown. Herein, using immunofluorescence and confocal microscopy, we show that Vpr forms nuclear foci in several cell types including HeLa cells and primary CD4+ T-lymphocytes. These nuclear foci contain VPRBP and partially overlap with DNA repair foci components such as γ-H2AX, 53BP1 and RPA32. While treatment with the non-specific ATR inhibitor caffeine or depletion of VPRBP by siRNA did not inhibit formation of Vpr nuclear foci, mutations in the C-terminal domain of Vpr and cytoplasmic sequestration of Vpr by overexpression of Gag-Pol resulted in impaired formation of these nuclear structures and defective G2 arrest. Consistently, we observed that G2 arrest-competent sooty mangabey Vpr could form these foci but not its G2 arrest-defective paralog Vpx, suggesting that formation of Vpr nuclear foci represents a critical early event in the induction of G2 arrest. Indeed, we found that Vpr could associate to chromatin via its C-terminal domain and that it could form a complex with VPRBP on chromatin. Finally, analysis of Vpr nuclear foci by time-lapse microscopy showed that they were highly mobile and stable structures. Overall, our results suggest that Vpr recruits the DDB1-CUL4A (VPRBP) E3 ligase to these nuclear foci and uses these mobile structures to target a chromatin-bound cellular substrate for ubiquitination in order to induce DNA damage/replication stress, ultimately leading to ATR activation and G2 cell cycle arrest

Is Religious Liberty Under Threat in America?:

A panel of experts in theology and constitutional law examined threats to religious liberty in America at a campus forum moderated by Vatican expert and author John L. Allen, Jr. of National Catholic Reporter and sponsored by the Church in the 21st Century Center, BC Law School and the School of Theology and Ministry

Improving the behavior of concrete exposed to fire by using an air entraining agent (AEA): Assessment of spalling

Several concrete mixes have been designed to evaluate the influence of an air entraining agent (AEA) on spalling. Tests have been performed under the ISO curve (occasionally under the HCinc curve) on specimens of various sizes and shapes to assess spalling. Results were somehow erratic on the smallest specimens whereas the beneficial effect of the air-bubble network could be emphasized on slabs

Hollow fiber membrane contactors for CO2 capture: From lab-scale screening to pilot-plant module conception

International audiencePost combustion Carbon Capture and Storage technology (CCS) is viewed as an efficient solution to reduce CO2 emissions of coal-fired power stations. In CCS, an aqueous amine solution can be used as a chemical solvent to selectively remove CO2 from the gas stream. The gas/liquid contact is performed within an absorption tower consisting of a packed column over which the absorption liquid and gas are flowing counter currently. The large active area required for CO2 mass transfer efficiency from the gas into the liquid induces the use of large absorption tower, which drastically increases the cost of the process. An alternative technology to packed column is using hollow fibers membrane contactors (HFMC) as they offer attractive potentialities for intensified gas absorption processes. This holds especially for post combustion CO2 capture application, for which a significant decrease of the size of the absorber or stripper unit could be of great interest. The aim of this work is to identify a suitable membrane material through lab-scale measurements to design a pilot-scale hollow fiber membrane contactor module

Interaction de H et de O atomique avec un hydrocarbure aromatique polycyclique neutre

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Interaction O(3P) with coronene: ketene or ketenyl fomration ?

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