1,017 research outputs found

    The relaxation of OH (v = 1) and OD (v = 1) by H2O and D2O at temperatures from 251 to 390 K

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    We report rate coefficients for the relaxation of OH(v = 1) and OD(v = 1) by H2O and D2O as a function of temperature between 251 and 390 K. All four rate coefficients exhibit a negative dependence on temperature. In Arrhenius form, the rate coefficients for relaxation (in units of 10–12 cm3 molecule–1 s–1) can be expressed as: for OH(v = 1) + H2O between 263 and 390 K: k = (2.4 ± 0.9) exp((460 ± 115)/T); for OH(v = 1) + D2O between 256 and 371 K: k = (0.49 ± 0.16) exp((610 ± 90)/T); for OD(v = 1) + H2O between 251 and 371 K: k = (0.92 ± 0.16) exp((485 ± 48)/T); for OD(v = 1) + D2O between 253 and 366 K: k = (2.57 ± 0.09) exp((342 ± 10)/T). Rate coefficients at (297 ± 1 K) are also reported for the relaxation of OH(v = 2) by D2O and the relaxation of OD(v = 2) by H2O and D2O. The results are discussed in terms of a mechanism involving the formation of hydrogen-bonded complexes in which intramolecular vibrational energy redistribution can occur at rates competitive with re-dissociation to the initial collision partners in their original vibrational states. New ab initio calculations on the H2O–HO system have been performed which, inter alia, yield vibrational frequencies for all four complexes: H2O–HO, D2O–HO, H2O–DO and D2O–DO. These data are then employed, adapting a formalism due to Troe (J. Troe, J. Chem. Phys., 1977, 66, 4758), in order to estimate the rates of intramolecular energy transfer from the OH (OD) vibration to other modes in the complexes in order to explain the measured relaxation rates—assuming that relaxation proceeds via the hydrogen-bonded complexes

    A Report on the Preliminary design of Composite Cocured LCA Fin

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    A report on the preliminary design of composite cocured LCA fin is presented. A six spar structural configuration involving laminated carbon composite construction is employed in the design of torsion box. The design studies are carried out using a strength of materials based analysis. Three critical loading cases have been considered in the investigation. Results for various cases studied are presented and discussed

    Resistance to simian immunodeficiency virus low dose rectal challenge is associated with higher constitutive TRIM5α expression in PBMC

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    Background: At least six host-encoded restriction factors (RFs), APOBEC3G, TRIM5α, tetherin, SAMHD1, schlafen 11, and Mx2 have now been shown to inhibit HIV and/or SIV replication in vitro. To determine their role in vivo in the resistance of macaques to mucosally-acquired SIV, we quantified both pre-exposure (basal) and post-exposure mRNA levels of these RFs, Mx1, and IFNγ in PBMC, lymph nodes, and duodenum of rhesus macaques undergoing weekly low dose rectal exposures to the primary isolate, SIV/DeltaB670. Results: Repetitive challenge divided the monkeys into two groups with respect to their susceptibility to infection: highly susceptible (2–3 challenges, 5 monkeys) and poorly susceptible (≥6 challenges, 3 monkeys). Basal RF and Mx1 expression varied among the three tissues examined, with the lowest expression generally detected in duodenal tissues, and the highest observed in PBMC. The one exception was A3G whose basal expression was greatest in lymph nodes. Importantly, significantly higher basal expression of TRIM5α and Mx1 was observed in PBMC of animals more resistant to mucosal infection. Moreover, individual TRIM5α levels were stable throughout a year prior to infection. Post-exposure induction of these genes was also observed after virus appearance in plasma, with elevated levels in PBMC and duodenum transiently occurring 7–10 days post infection. They did not appear to have an effect on control of viremia. Interestingly, minimal to no induction was observed in the resistant animal that became an elite controller. Conclusions: These results suggest that constitutively expressed TRIM5α appears to play a greater role in restricting mucosal transmission of SIV than that associated with type I interferon induction following virus entry. Surprisingly, this association was not observed with the other RFs. The higher basal expression of TRIM5α observed in PBMC than in duodenal tissues emphasizes the understated role of the second barrier to systemic infection involving the transport of virus from the mucosal compartment to the blood. Together, these observations provide a strong incentive for a more comprehensive examination of the intrinsic, variable control of constitutive expression of these genes in the sexual transmission of HIV

    Aerosol perturbations related to volcanic eruptions during the past few centuries as recorded in an ice core from the Central Dronning Maud Land, Antarctica

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    High-resolution glacio-chemical analyses were carried out in a 62.2 m long ice core recovered from the Central Dronning Maud Land, East Antarctica, to evaluate temporal changes in environmental characteristics during the past five centuries. The sulphate (SO 4 2-) content within the core varied between 15 and 377 ppb, whereas the sodium (Na +) and chloride (Cl -) content fluctuated widely from 7 to 500 ppb and 25 to 1461 ppb respectively. The computed non-sea-salt sulphate (nssSO 4 2-) record reveals the existence of several outstanding peaks that can be attributed to the sulphate aerosol deposition during large volcanic events as recorded in Antarctica and elsewhere. Major volcanic events identified at the core site include: Mt Pinatubo (1991), Agung (1963), Krakatau/Tarawera (1883/1886), Tambora (1815) and Huaynaputina (1600) among several other moderate events. Comparison of our nssSO 4 2- record with that of ice core records from Greenland reveals analogous sulphate deposition during certain major volcanic events, demonstrating the interhemispheric transport of aerosols during large volcanic eruptions. Relatively high Cl -/Na + ratio throughout the core (mean 3.1) compared to that of the sea water ratio implies additional sources of Cl -, most likely due to the intense scavenging of gaseous Cl - in the lower atmosphere

    Reduction of seafood processing wastewater using technologies enhanced by swim–bed technology

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    The increasing growth of the seafood processing industries considerably requires more industrial process activities and water consumption. It is estimated that approximately 10–40 m3 of wastewater is generated from those industries for processing one-tonne of raw materials. Due to limitations and regulations in natural resources utilization, a suitable and systematic wastewater treatment plant is very important to meet rigorous discharge standards. As a result of food waste biodegradability, the biological treatment and some extent of swim-bed technology, including a novel acryl-fibre (biofilm) material might be used effectively to meet the effluent discharge criteria. This chapter aims to develop understanding on current problems and production of the seafood wastewater regarding treatment efficiency and methods of treatment

    Randomised controlled trial and health economic evaluation of the impact of diagnostic testing for influenza, respiratory syncytial virus and Streptococcus pneumoniae infection on the management of acute admissions in the elderly and high-risk 18- to 64-year-olds

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    Please cite the published version which is available via the DOI link in this record.Western industrialised nations face a large increase in the number of older people. People over the age of 60 years account for almost half of the 16.8 million hospital admissions in England from 2009 to 2010. During 2009-10, respiratory infections accounted for approximately 1 in 30 hospital admissions and 1 in 20 of the 51.5 million bed-days.HTA ProgrammeNational Institute for Health Research (NIHR

    Gestational weight gain and its association with obstetric and fetal outcome

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    Background: Gestational weight gain (GWG) is a key determinant of maternal and neonatal outcomes, influenced by maternal pre-pregnancy body mass index (BMI), nutrition, and adherence to guidelines. Deviations from optimal GWG, particularly inadequate weight gain, are associated with adverse outcomes, including preterm birth, low birth weight (LBW), and increased caesarean delivery rates. While Institute of Medicine (IOM) guidelines offer recommendations for appropriate GWG, adherence remains suboptimal in many populations, particularly in developing countries. Methods: A retrospective observational study was conducted at Chettinad Hospital and Research Institute, involving 264 postnatal mothers. Participants were categorized into two groups based on GWG relative to IOM guidelines: group 1 (inadequate GWG) and group 2 (adequate GWG). Data on maternal height, pre-pregnancy weight, first- and third-trimester weight, and outcomes were retrieved from antenatal records. Statistical analyses were performed to evaluate associations, with significance set at p<0.05. Results: Inadequate GWG was observed in 50% of participants. Group 1 had higher rates of caesarean delivery (52.3% versus 32.6%, p=0.02), preterm births (21.9% versus 9.1%, p=0.01) and LBW neonates (28.8% versus 9.1%, p<0.001) compared to group 2. Mean birth weight was significantly lower in group 1 (2.7±0.4 kg versus 3.2±0.3 kg, p<0.001). Conclusions: Inadequate GWG is significantly associated with adverse maternal and neonatal outcomes, including increased caesarean delivery rates, preterm births, and LBW. Pre-pregnancy BMI is a critical determinant of GWG adequacy. These findings underscore the need for tailored antenatal interventions to promote optimal GWG and improve pregnancy outcomes
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