1,537 research outputs found

    A revision of the genus Gymnetina Casey, 1915 (Coleoptera: Scarabaeidae: Cetoniinae: Gymnetini)

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    The genus Gymnetina Casey (Coleoptera: Scarabaeidae: Cetoniinae: Gymnetini) is redescribed and revised. Three new species and one new subspecies are described: G. borealis Warner and Ratcliffe, G. grossepunctata Ratcliffe and Warner, G. howdeni Warner and Ratcliffe, and G. cretacea sundbergi Warner and Ratcliffe. Gymnetina salicis (Bates), new status, is removed from synonymy with G. cretacea (LeConte), and G. alboscripta (Janson) is transferred from Gymnetis MacLeay to Gymnetina becoming Gymnetina alboscripta (Janson), new combination. Redescriptions of previously known species, a key for identification, and illustrations of the six species are provided. A brief biogeographical analysis suggests that ancestral taxa dispersed northwards from Guatemala and Mexico to the southwestern United States

    A revision of the genus \u3ci\u3eGymnetina\u3c/i\u3e Casey, 1915 (Coleoptera: Scarabaeidae: Cetoniinae: Gymnetini)

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    The genus Gymnetina Casey (Coleoptera: Scarabaeidae: Cetoniinae: Gymnetini) is redescribed and revised. Three new species and one new subspecies are described: G. borealis Warner and Ratcliffe, G. grossepunctata Ratcliffe and Warner, G. howdeni Warner and Ratcliffe, and G. cretacea sundbergi Warner and Ratcliffe. Gymnetina salicis (Bates), new status, is removed from synonymy with G. cretacea (LeConte), and G. alboscripta (Janson) is transferred from Gymnetis MacLeay to Gymnetina becoming Gymnetina alboscripta (Janson), new combination. Redescriptions of previously known species, a key for identification, and illustrations of the six species are provided. A brief biogeographical analysis suggests that ancestral taxa dispersed northwards from Guatemala and Mexico to the southwestern United States

    Letter: Faecal volatile organic metabolites, promising biomarkers in inflammatory bowel disease and Letter: Faecal volatile organic metabolites as novel diagnostic biomarkers in inflammatory bowel disease. Authors' reply

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    The aetiology of inflammatory bowel disease (IBD) remains poorly understood. Recent evidence suggests an important role of gut microbial dysbiosis in IBD, and this may be associated with changes in faecal volatile organic metabolites (VOMs).To describe the changes in the faecal VOMs of patients with IBD and establish their diagnostic potential as non-invasive biomarkers.Faecal samples were obtained from 117 people with Crohn's disease (CD), 100 with ulcerative colitis (UC), and 109 healthy controls. Faecal VOMs were extracted using solid-phase micro-extraction and analysed by gas chromatography mass spectrometry. Data analysis was carried out using partial least squares-discriminate analysis (PLS-DA) to determine class membership based on distinct metabolomic profiles.The PLS-DA model showed clear separation of active CD from inactive disease and healthy controls (P < 0.001). Heptanal, 1-octen-3-ol, 2-piperidinone and 6-methyl-2-heptanone were up-regulated in the active CD group [variable important in projection (VIP) score 2.8, 2.7, 2.6 and 2.4, respectively], while methanethiol, 3-methyl-phenol, short-chain fatty acids and ester derivatives were found to be less abundant (VIP score of 3.5, 2.6, 1.5 and 1.2, respectively). The PLS-DA model also separated patients with small bowel CD from healthy controls and those with colonic CD from UC (P < 0.001). In contrast, less distinct separation was observed between active UC, inactive UC and healthy controls.Analysis of faecal volatile organic metabolites can provide an understanding of gut metabolomic changes in IBD. It has the potential to provide a non-invasive means of diagnosing IBD, and can differentiate between UC and CD

    Proton spin-lattice relaxation and methyl group rotation

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    Proton spin-lattice relaxation times have been measured at 16, 31, and 59 MHz in 4-methyl-2,6-ditertiarybutyl phenol between 80 K and its melting point, 340 K. The variation of T1 with temperature shows too distinct minima. The lower-temperature minimum has been analyzed in terms of relaxation by reorientation of four of the six t-butyl methyl groups with an average apparent activation energy of about 2.4 kcal mole−1 (104 meV molecule−1). The higher-temperature minimum has been analyzed in terms of relaxation by reorientation of the t-butyl groups about their C3 axes with four of the six t-butyl methyl groups reorienting very rapidly, and the remaining two reorienting with correlation time similar to that of the t-butyl group. The activation energy for the higher-temperature minimum is 5.76 kcal mole−1 (250 meV molecule−1). Steric potential calculations are used to add weight to these assignments, and a number of peculiarities displayed by the lower-temperature minimum are discussed

    Proton spin-lattice relaxation and methyl group rotation

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    Proton spin-lattice relaxation times have been measured at 16, 31, and 59 MHz in 4-methyl-2,6-ditertiarybutyl phenol between 80 K and its melting point, 340 K. The variation of T1 with temperature shows too distinct minima. The lower-temperature minimum has been analyzed in terms of relaxation by reorientation of four of the six t-butyl methyl groups with an average apparent activation energy of about 2.4 kcal mole−1 (104 meV molecule−1). The higher-temperature minimum has been analyzed in terms of relaxation by reorientation of the t-butyl groups about their C3 axes with four of the six t-butyl methyl groups reorienting very rapidly, and the remaining two reorienting with correlation time similar to that of the t-butyl group. The activation energy for the higher-temperature minimum is 5.76 kcal mole−1 (250 meV molecule−1). Steric potential calculations are used to add weight to these assignments, and a number of peculiarities displayed by the lower-temperature minimum are discussed

    A study of volatile compounds in the breath of children with type 1 diabetes

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    A pilot study of exhaled volatile compounds and their correlation with blood glucose levels in eight children with type 1 diabetes is reported. Five paired blood and breath samples were obtained from each child over a 6 hour period. The blood glucose concentration ranged from 41.4 to 435.6 mg/dL. Breath samples were collected in Tedlar bags and immediately evacuated through thermal desorption tubes packed with Carbopack B and C. The VOCs were later recovered by thermal desorption and analysed using gas chromatography mass spectrometry. The study identified 74 volatile compounds present in at least 10% of the patient samples. Of these 74 volatiles 36 were found in all patient samples tested. Further analysis of the 36 compounds found that none showed significant overall correlation with blood glucose levels. Isoprene showed a weak negative correlation with blood glucose levels. Acetone was found to have no correlation with blood glucose levels for the patients studied. Some patients showed significant individual correlation between the relative peak areas of certain compounds and blood glucose levels. However, there was no consistent pattern observed within these results across all 8 patients. Additional breath samples were collected in Tedlar bags and analysed using SIFTMS for 3 of the patients and a healthy control. The levels of 24 volatiles are reported and were found to be generally consistent with previously reported SIFT-MS data. In agreement with the GCMS data, no compounds exhibited a significant overall correlation with blood glucose level

    Assessing the construct validity of the Quality-of-Life-Aged Care Consumers (QOL-ACC): an aged care-specific quality-of-life measure.

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    PURPOSE: To evaluate the construct (convergent and known group) validity of the Quality-of-Life-Aged Care Consumer (QOL-ACC), an older-person-specific quality-of-life measure designed for application in quality assessment and economic evaluation in aged care. METHODS: Convergent validity was assessed by examining relationships with other validated preference-based measures (EQ-5D-5L, ASCOT), quality of aged care experience (QCE-ACC) and life satisfaction (PWI) through an online survey. Known-group validity was assessed by testing the ability to discriminate varying levels of care needs, self-reported health and quality of life. RESULTS: Older people (aged ≥ 65 years) receiving community-aged care (N = 313) responded; 54.6% were female, 41.8% were living alone and 56.8% were receiving higher-level care. The QOL-ACC and its six dimensions were low to moderately and significantly correlated with the EQ-5D-5L (correlation co-efficient range, ρ = 0.39-0.56). The QOL-ACC demonstrated moderate and statistically significant correlations with ASCOT (ρ = 0.61), the QCE-ACC (ρ = 0.51) and the PWI (ρ = 0.70). Respondents with poorer self-reported health status, quality of life and/or higher-level care needs demonstrated lower QOL-ACC scores (P < 0.001), providing evidence of known-group validity. CONCLUSIONS: The study provides evidence of the construct validity of the QOL-ACC descriptive system. A preference-weighted value set is currently being developed for the QOL-ACC, which when finalised will be subjected to further validation assessments

    Mutation analysis of HIF prolyl hydroxylases (PHD/EGLN) in individuals with features of phaeochromocytoma and renal cell carcinoma susceptibility

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    Germline mutations in the von Hippel–Lindau disease (VHL) and succinate dehydrogenase subunit B (SDHB) genes can cause inherited phaeochromocytoma and/or renal cell carcinoma(RCC). Dysregulation of the hypoxia-inducible factor (HIF) transcription factors has been linked to VHL and SDHB-related RCC; both HIF dysregulation and disordered function of a prolyl hydroxylase domain isoform 3 (PHD3/EGLN3)-related pathway of neuronal apoptosis have been linked to the development of phaeochromocytoma. The 2-oxoglutarate-dependent prolyl hydroxylase enzymes PHD1 (EGLN2), PHD2 (EGLN1) and PHD3 (EGLN3) have a key role in regulating the stability of HIF-a subunits (and hence expression of the HIF-a transcription factors). A germline PHD2 mutation has been reported in association with congenital erythrocytosis and recurrent extra-adrenal phaeochromocytoma. We undertook mutation analysis of PHD1, PHD2 and PHD3 in two cohorts of patients with features of inherited phaeochromocytoma (nZ82) and inherited RCC (nZ64) and no evidence of germline mutations in known susceptibility genes. No confirmed pathogenic mutations were detected suggesting that mutations in these genes are not a frequent cause of inherited phaeochromocytoma or RCC

    A comparison of weak-turbulence and PIC simulations of weak electron-beam plasma interaction

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    Quasilinear theory has long been used to treat the problem of a weak electron beam interacting with plasma and generating Langmuir waves. Its extension to weak-turbulence theory treats resonant interactions of these Langmuir waves with other plasma wave modes, in particular ion-sound waves. These are strongly damped in plasma of equal ion and electron temperatures, as sometimes seen in, for example, the solar corona and wind. Weak turbulence theory is derived in the weak damping limit, with a term describing ion-sound wave damping then added. In this paper we use the EPOCH particle-in-cell code to numerically test weak turbulence theory for a range of electron-ion temperature ratios. We find that in the cold ion limit the results agree well, but increasing ion temperature the three-wave resonance becomes broadened in proportion to the ion-sound wave damping rate. This may be important in, for example, the theory of solar radio bursts, where the spectrum of Langmuir waves is critical. Additionally we establish lower limits on the number of simulation particles needed to accurately reproduce the electron and wave distributions in their saturated states, and to reproduce their intermediate states and time evolution.Comment: Accepted by PO
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