Ortho-para transition rate in μ\mu-molecular hydrogen and the proton's induced pseudoscalar coupling gpg_p

We report a measurement of the ortho-para transition rate in the p$\mu$p molecule. The experiment was conducted at TRIUMF via the measurement of the time dependence of the 5.2 MeV neutrons from muon capture in liquid hydrogen. The measurement yielded an ortho-para rate $\Lambda_{op} = (11.1 \pm 1.7 \pm^{0.9}_{0.6}) \times 10^4$ s$^{-1}$ that is substantially larger than the earlier result of Bardin {\it et al.} We discuss the striking implications for the proton's induced pseudoscalar coupling $g_p$.Comment: 4 pages, 3 figures, submitted to Phys. Rev. Let

Parity Violation in Proton-Proton Scattering at 221 MeV

TRIUMF experiment 497 has measured the parity violating longitudinal analyzing power, A_z, in pp elastic scattering at 221.3 MeV incident proton energy. This paper includes details of the corrections, some of magnitude comparable to A_z itself, required to arrive at the final result. The largest correction was for the effects of first moments of transverse polarization. The addition of the result, A_z=(0.84 \pm 0.29 (stat.) \pm 0.17 (syst.)) \times 10^{-7}, to the pp parity violation experimental data base greatly improves the experimental constraints on the weak meson-nucleon coupling constants h^{pp}_\rho and h^{pp}_\omega, and has implications for the interpretation of electron parity violation experiments.Comment: 17 pages RevTeX, 14 PostScript figures. Revised version with additions suggested by Phys. Rev.

Parity Violation in Proton-Proton Scattering at 221 MeV

The parity-violating longitudinal analyzing power, Az, has been measured in pp elastic scattering at an incident proton energy of 221 MeV. The result obtained is Az =(0.84 +/- 0.29 (stat.) +/- 0.17 (syst.)) x 10^{-7}. This experiment is unique in that it selects a single parity violating transition amplitude, 3P2-1D2, and consequently directly constrains the weak meson-nucleon coupling constant h^pp_rho When this result is taken together with the existing pp parity violation data, the weak meson-nucleon coupling constants h^pp_rho and h^pp_omega can, for the first time, both be determined.Comment: 8 pages RevTeX4, 3 PostScript figures. Conclusion revised. New information about weak coupling constants adde

Thermostable DNA Polymerase from a Viral Metagenome Is a Potent RT-PCR Enzyme

Viral metagenomic libraries are a promising but previously untapped source of new reagent enzymes. Deep sequencing and functional screening of viral metagenomic DNA from a near-boiling thermal pool identified clones expressing thermostable DNA polymerase (Pol) activity. Among these, 3173 Pol demonstrated both high thermostability and innate reverse transcriptase (RT) activity. We describe the biochemistry of 3173 Pol and report its use in single-enzyme reverse transcription PCR (RT-PCR). Wild-type 3173 Pol contains a proofreading 3′-5′ exonuclease domain that confers high fidelity in PCR. An easier-to-use exonuclease-deficient derivative was incorporated into a PyroScript RT-PCR master mix and compared to one-enzyme (Tth) and two-enzyme (MMLV RT/Taq) RT-PCR systems for quantitative detection of MS2 RNA, influenza A RNA, and mRNA targets. Specificity and sensitivity of 3173 Pol-based RT-PCR were higher than Tth Pol and comparable to three common two-enzyme systems. The performance and simplified set-up make this enzyme a potential alternative for research and molecular diagnostics

A Global Metabolic Shift Is Linked to Salmonella Multicellular Development

Bacteria can elaborate complex patterns of development that are dictated by temporally ordered patterns of gene expression, typically under the control of a master regulatory pathway. For some processes, such as biofilm development, regulators that initiate the process have been identified but subsequent phenotypic changes such as stress tolerance do not seem to be under the control of these same regulators. A hallmark feature of biofilms is growth within a self-produced extracellular matrix. In this study we used metabolomics to compare Salmonella cells in rdar colony biofilms to isogenic csgD deletion mutants that do not produce an extracellular matrix. The two populations show distinct metabolite profiles. Even though CsgD controls only extracellular matrix production, metabolite signatures associated with cellular adaptations associated with stress tolerances were present in the wild type but not the mutant cells. To further explore these differences we examine the temporal gene expression of genes implicated in biofilm development and stress adaptations. In wild type cells, genes involved in a metabolic shift to gluconeogenesis and various stress-resistance pathways exhibited an ordered expression profile timed with multicellular development even though they are not CsgD regulated. In csgD mutant cells, the ordered expression was lost. We conclude that the induction of these pathways results from production of, and growth within, a self produced matrix rather than elaboration of a defined genetic program. These results predict that common physiological properties of biofilms are induced independently of regulatory pathways that initiate biofilm formation

The disruption of proteostasis in neurodegenerative diseases

Cells count on surveillance systems to monitor and protect the cellular proteome which, besides being highly heterogeneous, is constantly being challenged by intrinsic and environmental factors. In this context, the proteostasis network (PN) is essential to achieve a stable and functional proteome. Disruption of the PN is associated with aging and can lead to and/or potentiate the occurrence of many neurodegenerative diseases (ND). This not only emphasizes the importance of the PN in health span and aging but also how its modulation can be a potential target for intervention and treatment of human diseases.info:eu-repo/semantics/publishedVersio

Phytochemical screening of Pulsatilla species and investigation of their biological activities

The present study aimed to identify biologically active secondary metabolites from the rare plant species, Pulsatilla patens subsp. patens and the cultivated P. vulgaris subsp. vulgaris. Chromatographic fractionation of the ethanolic extract of the roots of P. patens subsp. patens resulted in the isolation of two oleanane-type glycosides identified as hederagenin 3-O-β-d-glucopyranoside (2.7 mg) and hederagenin 3-O-β-d-galactopyranosyl-(1→2)-β-d-glucopyranoside (3.3 mg, patensin). HPLC analysis of the methanolic extract of the crude root of P. patens subsp. patens and P. vulgaris subsp. vulgaris revealed the presence of Pulsatilla saponin D (hederagenin 3-O-α-l-rhamnopyranosyl(1→2)-[β-d-glucopyranosyl(1→4)]-α-l-arabinopyranoside). Chromatographic analysis using GC-MS of the silylated methanolic extracts from the leaves and roots of these species identified the presence of carboxylic acids, such as benzoic, caffeic, malic, and succinic acids. The extracts from Pulsatilla species were tested for their antifungal, antimicrobial, and antimalarial activities, and cytotoxicity to mammalian cell lines. Both P. patens subsp. patens and P. vulgaris subsp. vulgaris were active against the fungus Candida glabrata with the half-maximal inhibitory concentration (IC₅₀) values of 9.37 μg/mL and 11 μg/mL, respectively. The IC₅₀ values for cytotoxicity evaluation were in the range of 32–38 μg/mL for P. patens subsp. patens and 35–57 μg/mL for P. vulgaris subsp. vulgaris for each cell line, indicating general cytotoxic activity throughout the panel of evaluated cancer and noncancer cells

Proteomic profiling to identify potential biomarkers of alpha-particle radiation exposure in human lung epithelial cells

Of the radiation types, alpha-(α) particles are of particular interest as they are an environmental concern, predominately due to inhalation of radon and its daughter progeny. Furthermore, α-particle emitters like Americium-241, Plutonium-238 and Polonium-210 have been identified as probable isotopes to be used in radiological dispersal devices. Thus, the identification of potential biomarkers to α-particle radiation exposure would be useful for the development of field deployable bioassays which could be used for human risk assessment and public health protection. Human lung cells were exposed to α-particle radiation and assessed for modulations in protein expression using two-dimensional gel electrophoresis (2D-GE). Concurrently, cell culture supernatants were analyzed for cytokine secretion using a multiplex-27 bead array assay. Cell culture supernatants assessed for cytokine secretion expressed 8 statistically significant cytokines following α-particle exposure, among which VEGF was confirmed to be dose-responsive and not modulated in X-irradiated cells. Analysis of whole cell lysates using 2-D gel electrophoresis showed 15 upregulated and 1 downregulated protein spot, of which 4 were identified by mass spectrometry. These data suggest that α-particle exposure results in the alterations in expression-levels of specific proteins which may be potential biomarkers used further for the development of fast and reliable bioassays

Monte Carlo simulations of semi-infinite clouds of radioactive noble gases

Health Canada maintains detector networks across Canada. One of these networks consists of NaI(Tl) detectors that measure air KERMA [1]. Located beside the NaI(Tl) detector in Ottawa is a radioxenon analyzer [2] that measures the activity concentration of 131m, 133m, 133, 135Xe directly. The ICRU-accepted KERMA to activity concentration conversion factor for 133Xe, for a semi-infinite cloud measured 1 m off the ground, is 9.68 pGy/hr per Bq/m3 [3]. However, on various dates, the two detectors in Ottawa reported a conversion value of 2.6 ± 0.2 pGy/hr per Bq/m3; we have resolved this discrepancy [4] and have expanded on the study of other isotopes by focusing on the NaI(Tl) detector. Greater accuracy in the conversion value between the air KERMA and activity concentration will assist meteorological modellers in verifying their models [1]. Two Monte Carlo methods were used in this investigation. The first is the analogue geometry where the detector is immersed in a semi-infinite radioactive source. A second method is to apply a reciprocal transform of the analogue geometry. This expedited the calculation of larger clouds. By using these two methods together, we have calculated new values for KERMA rate to activity concentration for 4 of isotopes of noble gases, namely 131mXe, 133mXe, 85Kr, 85mKr, 135Xe

Male-female differences in the genetic regulation of t-PA and PAI-1 levels in a Ghanaian population

Tissue-type plasminogen activator (t-PA) and plasminogen activator inhibitor-1 (PAI-1) directly influence thrombus formation and degradation, and have been identified as risk factors for thromboembolic disease. Prior studies investigated determinants of t-PA and PAI-1 expression, but mainly in Caucasian subjects. The aim of this study was to identify the contributions of genetic and other factors to inter-individual variation in plasma levels of t-PA and PAI-1 in a large-scale population-based sample from urban West Africa. t-PA, PAI-1 and several demographic, anthropometric, and metabolic parameters were measured in 992 residents of Sunyani, the capital of the Brong-Ahafo region of Ghana. In addition, nine gene polymorphisms associated with components of the renin-angiotensin and fibrinolytic systems were determined. We found that BMI, systolic and diastolic blood pressure, total cholesterol, glucose, and triglycerides were all significant predictors of t-PA and PAI-1 in both females and males. In addition, a significant relationship was found between the PAI-1 4G/5G (rs1799768) polymorphism on PAI-1 levels in females, the TPA I/D (rs4646972) polymorphism on t-PA and PAI-1 in males, the renin (rs3730103) polymorphism on t-PA and PAI-1 in males, the ethanolamine kinase 2 (rs1917542) polymorphism on PAI-1 in males, and the renin (rs1464816) polymorphism on t-PA in females and on PAI-1 in males. This study of urban West Africans shows that t-PA and PAI-1 levels are determined by both genetic loci of the fibrinolytic and renin-angiotensin systems and other factors often associated with cardiovascular disease, and that genetic factors differ between males and females