346 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
Objectives: Minerals such as zinc, copper, selenium, calcium, and magnesium are essential for normal human development and functioning of the body. They have been found to play important roles in immuno-physiologic functions. The study is to evaluate the distribution and correlation of nonessential (lead) and essential elements in whole blood from 1- to 72-month old children.Methods: The cross-sectional study was performed in 1551 children. Six element concentrations, including copper (Cu), zinc (Zn), calcium (Ca), magnesium (Mg), iron (Fe) and lead (Pb) in the blood were determined by atomic absorption spectrometry. Distributions and correlations of trace elements in different age groups were analyzed and compared. A Pearson 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 ± 4.42 μmol/L and 1.42 ± 0.12 mmol/L, respectively. 6.04% of all children showed copper levels below the normal threshold, the levels of Magnesium were stable in different age groups. Though the overall mean blood zinc and iron concentrations (61.19 ± 11.30 μmol/L and 8.24 ± 0.59 mmol/L, respectively) gradually increased with age and the overall deficiency levels (24.1% and 36.0%, respectively) decreased with age, zinc and iron deficiencies were still very stable. Controlling for gender and age, significant positive correlations were found when comparing copper to zinc, calcium, magnesium, and iron((r = 0.333, 0.241, 0.417, 0.314 ,p < 0.01); zinc to magnesium and 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 lead levels (41.16 ± 16.10) were relatively unstable among different age groups. The prevalence of lead intoxication in all children was 1.3% .Calcium levels decreased gradually with age, with an overall concentration of 1.78 ± 0.13 mmol/L.Conclusion: Significant negative correlations were also noted between Pb and Zn, Fe (r = -0.179, -0.124.p < 0.01) .The importance of calcium deficiency and supplementation is well realized, but the severity of iron and zinc deficiency is not well recorded. The degree of lead intoxication in all the children studied was low; The established reference intervals for Cu, Zn, Ca and Mg provide an important guidance for the reasonable supplementation of essential elements during different age groups.Keywords: prenatal biomonitoring, copper, zinc, calcium, magnesium, iron, lea
Elasticity of iron at the temperature of the Earth's inner core
Seismological body-wave(1) and free-oscillation(2) studies of the Earth's solid inner core have revealed that compressional waves traverse the inner core faster along near-polar paths than in the equatorial plane. Studies have also documented local deviations from this first-order pattern of anisotropy on length scales ranging from 1 to 1,000 km (refs 3, 4). These observations, together with reports of the differential rotation(5) of the inner core, have generated considerable interest in the physical state and dynamics of the inner core, and in the structure and elasticity of its main constituent, iron, at appropriate conditions of pressure and temperature. Here we report first-principles calculations of the structure and elasticity of dense hexagonal close-packed (h.c.p.) iron at high temperatures. We find that the axial ratio c/a of h.c.p. iron increases substantially with increasing temperature, reaching a value of nearly 1.7 at a temperature of 5,700 K, where aggregate bulk and shear moduli match those of the inner core. As a consequence of the increasing c/a ratio, we have found that the single-crystal longitudinal anisotropy of h.c.p. iron at high temperature has the opposite sense from that at low temperature(6,7). By combining our results with a simple model of polycrystalline texture in the inner core, in which basal planes are partially aligned with the rotation axis, we can account for seismological observations of inner-core anisotropy.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/62959/1/413057a0.pd
Observation of a ppb mass threshoud enhancement in \psi^\prime\to\pi^+\pi^-J/\psi(J/\psi\to\gamma p\bar{p}) decay
The decay channel
is studied using a sample of events collected
by the BESIII experiment at BEPCII. A strong enhancement at threshold is
observed in the invariant mass spectrum. The enhancement can be fit
with an -wave Breit-Wigner resonance function with a resulting peak mass of
and a
narrow width that is at the 90% confidence level.
These results are consistent with published BESII results. These mass and width
values do not match with those of any known meson resonance.Comment: 5 pages, 3 figures, submitted to Chinese Physics
Disparities and risks of sexually transmissible infections among men who have sex with men in China: a meta-analysis and data synthesis.
BACKGROUND: Sexually transmitted infections (STIs), including Hepatitis B and C virus, are emerging public health risks in China, especially among men who have sex with men (MSM). This study aims to assess the magnitude and risks of STIs among Chinese MSM. METHODS: Chinese and English peer-reviewed articles were searched in five electronic databases from January 2000 to February 2013. Pooled prevalence estimates for each STI infection were calculated using meta-analysis. Infection risks of STIs in MSM, HIV-positive MSM and male sex workers (MSW) were obtained. This review followed the PRISMA guidelines and was registered in PROSPERO. RESULTS: Eighty-eight articles (11 in English and 77 in Chinese) investigating 35,203 MSM in 28 provinces were included in this review. The prevalence levels of STIs among MSM were 6.3% (95% CI: 3.5-11.0%) for chlamydia, 1.5% (0.7-2.9%) for genital wart, 1.9% (1.3-2.7%) for gonorrhoea, 8.9% (7.8-10.2%) for hepatitis B (HBV), 1.2% (1.0-1.6%) for hepatitis C (HCV), 66.3% (57.4-74.1%) for human papillomavirus (HPV), 10.6% (6.2-17.6%) for herpes simplex virus (HSV-2) and 4.3% (3.2-5.8%) for Ureaplasma urealyticum. HIV-positive MSM have consistently higher odds of all these infections than the broader MSM population. As a subgroup of MSM, MSW were 2.5 (1.4-4.7), 5.7 (2.7-12.3), and 2.2 (1.4-3.7) times more likely to be infected with chlamydia, gonorrhoea and HCV than the broader MSM population, respectively. CONCLUSION: Prevalence levels of STIs among MSW were significantly higher than the broader MSM population. Co-infection of HIV and STIs were prevalent among Chinese MSM. Integration of HIV and STIs healthcare and surveillance systems is essential in providing effective HIV/STIs preventive measures and treatments. TRIAL REGISTRATION: PROSPERO NO: CRD42013003721
Activity of the multikinase inhibitor dasatinib against ovarian cancer cells
BackgroundHere, we explore the therapeutic potential of dasatinib, a small-molecule inhibitor that targets multiple cytosolic and membrane-bound tyrosine kinases, including members of the Src kinase family, EphA2, and focal adhesion kinase for the treatment of ovarian cancer.MethodsWe examined the effects of dasatinib on proliferation, invasion, apoptosis, cell-cycle arrest, and kinase activity using a panel of 34 established human ovarian cancer cell lines. Molecular markers for response prediction were studied using gene expression profiling. Multiple drug effect/combination index (CI) isobologram analysis was used to study the interactions with chemotherapeutic drugs.ResultsConcentration-dependent anti-proliferative effects of dasatinib were seen in all ovarian cancer cell lines tested, but varied significantly between individual cell lines with up to a 3 log-fold difference in the IC(50) values (IC(50) range: 0.001-11.3 micromol l(-1)). Dasatinib significantly inhibited invasion, and induced cell apoptosis, but less cell-cycle arrest. At a wide range of clinically achievable drug concentrations, additive and synergistic interactions were observed for dasatinib plus carboplatin (mean CI values, range: 0.73-1.11) or paclitaxel (mean CI values, range: 0.76-1.05). In this study, 24 out of 34 (71%) representative ovarian cancer cell lines were highly sensitive to dasatinib, compared with only 8 out of 39 (21%) representative breast cancer cell lines previously reported. Cell lines with high expression of Yes, Lyn, Eph2A, caveolin-1 and 2, moesin, annexin-1, and uPA were particularly sensitive to dasatinib.ConclusionsThese data provide a clear biological rationale to test dasatinib as a single agent or in combination with chemotherapy in patients with ovarian cancer
Pulse energy packing effects on material transport during laser processing of < 1
The effects of energy pulse packing on material transport during single-pulse laser processing of silicon is studied using temporarily shaped pulses with durations from 50 to 150 ns. Six regimes of material transport were identified and disambiguated through energy packing considerations over a range of pulse durations. Energy packing has been shown to shift the interaction to energetically costlier regimes without appreciable benefit in either depth, material removal or crater morphology and quality.The authors would like to thank the UK Technology Strategy Board under project TP14/HVM/6/I/BD5665. The authors acknowledge the EPSRC Centre for Doctoral Training in Photonic Systems Development for their generous support
A Computational Study on the Role of Gap Junctions and Rod Ih Conductance in the Enhancement of the Dynamic Range of the Retina
Recent works suggest that one of the roles of gap junctions in sensory systems is to enhance their dynamic range by avoiding early saturation in the first processing stages. In this work, we use a minimal conductance-based model of the ON rod pathways in the vertebrate retina to study the effects of electrical synaptic coupling via gap junctions among rods and among AII amacrine cells on the dynamic range of the retina. The model is also used to study the effects of the maximum conductance of rod hyperpolarization activated current Ih on the dynamic range of the retina, allowing a study of the interrelations between this intrinsic membrane parameter with those two retina connectivity characteristics. Our results show that for realistic values of Ih conductance the dynamic range is enhanced by rod-rod coupling, and that AII-AII coupling is less relevant to dynamic range amplification in comparison with receptor coupling. Furthermore, a plot of the retina output response versus input intensity for the optimal parameter configuration is well fitted by a power law with exponent . The results are consistent with predictions of more theoretical works and suggest that the earliest expression of gap junctions along the rod pathways, together with appropriate values of rod Ih conductance, has the highest impact on vertebrate retina dynamic range enhancement
Regulation of Epithelial Branching Morphogenesis and Cancer Cell Growth of the Prostate by Wnt Signaling
Although Wnt signaling has been shown to be important for embryonic morphogenesis and cancer pathogenesis of several tissues, its role in prostatic development and tumorigenesis is not well understood. Here we show that Wnt signaling regulated prostatic epithelial branching morphogenesis and luminal epithelial cell differentiation in developing rat prostate organ cultures. Specifically, Wnt signaling regulated the proliferation of prostate epithelial progenitor cells. Assessment of the expression levels of a Wnt pathway transcriptional target gene, Axin2, showed that the Wnt pathway was activated in the developing prostate, but was down-regulated in the adult. Castration resulted in an upregulation of Axin2 whereas androgen replacement resulted in a down regulation of Axin2. Such dynamic changes of Wnt activity was also confirmed in a BAT-gal transgenic mouse line in which β-galactosidase reporter is expressed under the control of β-catenin/T cell factor responsive elements. Furthermore, we evaluated the role of Wnt signaling in prostate tumorigenesis. Axin2 expression was found upregulated in the majority of human prostate cancer cell lines examined. Moreover, addition of a Wnt pathway inhibitor, Dickkopf 1 (DKK1), into the culture medium significantly inhibited prostate cancer cell growth and migration. These findings suggest that Wnt signaling regulates prostatic epithelial ductal branching morphogenesis by influencing cell proliferation, and highlights a role for Wnt pathway activation in prostatic cancer progression
Murine Gamma Herpesvirus 68 Hijacks MAVS and IKKβ to Abrogate NFκB Activation and Antiviral Cytokine Production
Upon viral infection, mitochondrial antiviral signaling (MAVS) protein serves as a key adaptor to promote cytokine production. We report here that murine gamma herpesvirus 68 (γHV68), a model virus for oncogenic human gamma herpesviruses, subverts cytokine production via the MAVS adaptor. During early infection, γHV68 hijacks MAVS and IKKβ to induce the site-specific phosphorylation of RelA, a crucial subunit of the transcriptionally active NFκB dimer, which primes RelA for the proteasome-mediated degradation. As such, γHV68 efficiently abrogated NFκB activation and cytokine gene expression. Conversely, uncoupling RelA degradation from γHV68 infection promoted NFκB activation and elevated cytokine production. Loss of MAVS increased cytokine production and immune cell infiltration in the lungs of γHV68-infected mice. Moreover, exogenous expression of the phosphorylation- and degradation-resistant RelA variant restored γHV68-induced cytokine production. Our findings uncover an intricate strategy whereby signaling via the upstream MAVS adaptor is intercepted by a pathogen to nullify the immediate downstream effector, RelA, of the innate immune pathway
Deletion of PKBα/Akt1 Affects Thymic Development
BACKGROUND: The thymus constitutes the primary lymphoid organ for the majority of T cells. The phosphatidyl-inositol 3 kinase (PI3K) signaling pathway is involved in lymphoid development. Defects in single components of this pathway prevent thymocytes from progressing beyond early T cell developmental stages. Protein kinase B (PKB) is the main effector of the PI3K pathway. METHODOLOGY/PRINCIPAL FINDINGS: To determine whether PKB mediates PI3K signaling in the thymus, we characterized PKB knockout thymi. Our results reveal a significant thymic hypocellularity in PKBalpha(-/-) neonates and an accumulation of early thymocyte subsets in PKBalpha(-/-) adult mice. Using thymic grafting and fetal liver cell transfer experiments, the latter finding was specifically attributed to the lack of PKBalpha within the lymphoid component of the thymus. Microarray analyses show that the absence of PKBalpha in early thymocyte subsets modifies the expression of genes known to be involved in pre-TCR signaling, in T cell activation, and in the transduction of interferon-mediated signals. CONCLUSIONS/SIGNIFICANCE: This report highlights the specific requirements of PKBalpha for thymic development and opens up new prospects as to the mechanism downstream of PKBalpha in early thymocytes
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