10,073 research outputs found

    Towards bio monitoring of toxic (lead) and essential elements in whole blood from 1- to72-month old children: a cross-sectional study

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    Objectives: Minerals such as zinc, copper, selenium, calcium, and magnesium are essential for normal human developmentĀ and functioning of the body. They have been found to play important roles in immuno-physiologic functions. The study isĀ to evaluate the distribution and correlation of nonessential (lead) and essential elements in whole blood from 1- to 72-monthĀ old children.Methods: The cross-sectional study was performed in 1551 children. Six element concentrations, including copper (Cu),Ā zinc (Zn), calcium (Ca), magnesium (Mg), iron (Fe) and lead (Pb) in the blood were determined by atomic absorption spectrometry.Ā Distributions and correlations of trace elements in different age groups were analyzed and compared. A PearsonĀ correlation controlled for age and gender was used to assess the relationship of non essential (lead) and essential elements.Results: Levels of copper and magnesium were 18.09 Ā± 4.42 Ī¼mol/L and 1.42 Ā± 0.12 mmol/L, respectively. 6.04% of allĀ children showed copper levels below the normal threshold, the levels of Magnesium were stable in different age groups.Ā Though the overall mean blood zinc and iron concentrations (61.19 Ā± 11.30 Ī¼mol/L and 8.24 Ā± 0.59 mmol/L, respectively)Ā gradually increased with age and the overall deficiency levels (24.1% and 36.0%, respectively) decreased with age, zinc andĀ iron deficiencies were still very stable. Controlling for gender and age, significant positive correlations were found whenĀ comparing copper to zinc, calcium, magnesium, and iron((r = 0.333, 0.241, 0.417, 0.314 ,p < 0.01); zinc to magnesium andĀ iron (r = 0.440, 0.497p < 0.01); and magnesium to Calcium and iron(r = 0.349, 0.645, p < 0.01). The overall mean blood leadĀ levels (41.16 Ā± 16.10) were relatively unstable among different age groups. The prevalence of lead intoxication in all childrenĀ was 1.3% .Calcium levels decreased gradually with age, with an overall concentration of 1.78 Ā± 0.13 mmol/L.Conclusion: Significant negative correlations were also noted between Pb and Zn, Fe (r = -0.179, -0.124.p < 0.01) .TheĀ importance of calcium deficiency and supplementation is well realized, but the severity of iron and zinc deficiency is notĀ well recorded. The degree of lead intoxication in all the children studied was low; The established reference intervals for Cu,Ā Zn, Ca and Mg provide an important guidance for the reasonable supplementation of essential elements during differentĀ age groups.Keywords: prenatal biomonitoring, copper, zinc, calcium, magnesium, iron, lea

    Regional difference of the start time of the recent warming in Eastern China: prompted by a 165-year temperature record deduced from tree rings in the Dabie Mountains

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    Tree-ring studies from tropical to subtropical regions are rarer than that from extratropical regions, which greatly limit our understanding of some critical climate change issues. Based on the tree-ring-width chronology of samples collected from the Dabie Mountains, we reconstructed the April-June mean temperature for this region with an explained variance of 46.8%. Five cold (1861-1869, 1889-1899, 1913-1920, 1936-1942 and 1952-1990) and three warm (1870-1888, 1922-1934 and 2000-2005) periods were identified in the reconstruction. The reconstruction not only agreed well with the instrumental records in and around the study area, but also showed good resemblance to previous temperature reconstructions from nearby regions, indicating its spatial and temporal representativeness of the temperature variation in the central part of eastern China. Although no secular warming trend was found, the warming trend since 1970 was unambiguous in the Dabie Mountains (0.064 A degrees C/year). Further temperature comparison indicated that the start time of the recent warming in eastern China was regional different. It delayed gradually from north to south, starting at least around 1940 AD in the north part, around 1970 AD in the central part and around 1980s in the south part. This work enriches the high-resolution temperature reconstructions in eastern China. We expect that climate warming in the future would promote the radial growth of alpine Pinus taiwanensis in the subtropical areas of China, therefore promote the carbon capture and carbon storage in the Pinus taiwanensis forest. It also helps to clarify the regional characteristic of recent warming in eastern China.</p

    Vortex Depinning in a Two-Dimensional Superfluid

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    \ua9 The Author(s) 2024.We employ the Grossā€“Pitaevskii theory to model a quantized vortex depinning from a small obstacle in a two-dimensional superfluid due to an imposed background superfluid flow. We find that, when the flowā€™s velocity exceeds a critical value, the vortex drifts orthogonally to the flow before subsequently moving parallel to it away from the pinning site. The motion of the vortex around the pinning site is also accompanied by an emission of a spiral-shaped sound pulse. Through simulations, we present a phase diagram of the critical flow velocity for vortex depinning together with an empirical formula that illustrates how the critical velocity increases with the height and width of the pinning site. By employing a variety of choices of initial and boundary conditions, we are able to obtain lower and upper bounds on the critical velocity and demonstrate the robustness of these results

    A scheme for demodulation of fiber grating sensors with high resolution

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    2000-2001 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

    Identification of furfural resistant strains of Saccharomyces cerevisiae and Saccharomyces paradoxus from a collection of environmental and industrial isolates

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    Background Fermentation of bioethanol using lignocellulosic biomass as a raw material provides a sustainable alternative to current biofuel production methods by utilising waste food streams as raw material. Before lignocellulose can be fermented it requires physical, chemical and enzymatic treatment in order to release monosaccharides, a process that causes the chemical transformation of glucose and xylose into the cyclic aldehydes furfural and hydroxyfurfural. These furan compounds are potent inhibitors of Saccharomyces fermentation, and consequently furfural tolerant strains of Saccharomyces are required for lignocellulosic fermentation. Results This study investigated yeast tolerance to furfural and hydroxyfurfural using a collection of 71 environmental and industrial isolates of the bakerā€™s yeast Saccharomyces cerevisiae and its closest relative Saccharomyces paradoxus. The Saccharomyces strains were initially screened for growth on media containing 100 mM glucose and 1.5 mg ml-1 furfural. Five strains were identified that showed a significant tolerance to growth in the presence of furfural and these were then screened for growth and ethanol production in the presence of increasing amounts (0.1-4 mg ml-1) of furfural. Conclusions Of the five furfural tolerant strains S. cerevisiae NCYC 3451 displayed the greatest furfural resistance, and was able to grow in the presence of up to 3.0 mg ml-1 furfural. Furthermore, ethanol production in this strain did not appear to be inhibited by furfural, with the highest ethanol yield observed at 3.0 mg ml-1 furfural. Although furfural resistance was not found to be a trait specific to any one particular lineage or population, three of the strains were isolated from environments where they might be continually exposed to low levels of furfural through the on-going natural degradation of lignocelluloses, and would therefore develop elevated levels of resistance to these furan compounds. Thus these strains represent good candidates for future studies of genetic variation relevant to understanding and manipulating furfural resistance and in the development of tolerant ethanologenic yeast strains for use in bioethanol production from lignocellulose processing

    Down-regulation of hippocampal genes regulating dopaminergic, GABAergic and glutamatergic function following combined neonatal phencyclidine and post-weaning social isolation of rats as a neurodevelopmental model for schizophrenia

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    Background: Dysfunction of dopaminergic, GABAergic and glutamatergic function underlies many core symptoms of schizophrenia. Combined neonatal injection of the N-methyl-D-aspartate (NMDA) receptor antagonist, phencyclidine (PCP) and post-weaning social isolation of rats produces a behavioral syndrome with translational relevance to several core symptoms of schizophrenia. This study uses DNA microarray to characterise alterations in hippocampal neurotransmitter-related gene expression and examines the ability of the sodium channel blocker, lamotrigine, to reverse behavioral changes in this model. Methods: Fifty-four male Lister-hooded rat pups either received phencyclidine (PCP, 10 mg/kg, s.c.), on post-natal day (PND) 7, 9 and 11 before being weaned on PND 23 into separate cages (isolation, PCP-SI, n=31), or vehicle injection and group-housing (2-4 per cage, V-GH, n=23) from weaning. The effect of lamotrigine on locomotor activity, novel object recognition, and prepulse inhibition of acoustic startle was examined (PND60-75) and drug-free hippocampal gene expression on PND70. Results: Acute lamotrigine (10-15mg/kg i.p.) reversed the hyperactivity and novel object recognition impairment induced by PCP-SI but had no effect on the prepulse inhibition deficit. Microarray revealed small but significant down-regulation of hippocampal genes involved in glutamate metabolism, dopamine neurotransmission and GABA receptor signalling, and in specific schizophrenia-linked genes, including PVALB and GAD67, in PCP-SI rats which resemble changes reported in schizophrenia. Conclusions: Findings indicate that alterations in dopamine neurotransmission, glutamate metabolism and GABA signalling may contribute to some of the behavioral deficits observed following PCP-SI, and that lamotrigine may have some utility as an adjunctive therapy to improve certain cognitive deficits symptoms in schizophrenia
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