131 research outputs found
Charge and critical density of strange quark matter
The electric charge of strange quark matter is of vital importance to
experiments. A recent investigation shows that strangelets are most likely
highly negatively charged, rather than slightly positively charged as
previously believed. Our present study indicates that negative charges can
indeed lower the critical density, and thus be favorable to the experimental
searches in heavy ion collisions. However, too much negative charges can make
it impossible to maintain flavor equilibrium.Comment: 4 pages, LATeX with REVTeX style, one PS figure. To be published in
Phys. Rev. C 59(6), 199
Vasorelaxation to Eugenol, Curcumin and Nanocurcumin mediated by differential augmentation of Na+, K+-ATPase activity in middle uterine artery of Capra hircus
59-67Sodium-potassium ATPase (Na, K-ATPase) is an integral protein universally distributed in the plasma membrane of all eukaryotic cells. It regulates trans-epithelial sodium ion transport, muscle contraction, nerve excitability, secretary functions and intracellular signaling. We investigated the mechanism of vasorelaxation effect of Eugenol, Curcumin and Nanocurcumin in the middle uterine artery (MUA) of goat to evaluate their possible therapeutic potential in hypertension during pregnancy or pre-eclampsia. The UA rings were isometrically contracted by K+-free MKHS to plateau and relaxed with KCl (10 μM-10 mM) following standard protocol. The K+ -vasorelaxation response (VR) was taken either in presence of ouabain with or without Eugenol/Curcumin/Nanocurcumin (10 μM). Rmax (maximum % vasorelaxation) of K+-induced VR-curve elicited in UA rings was reduced (from 6.90% and 26.55%) to 4-5% in presence of Ouabain in both NP and P goats. Rmax obtained from KVR curve elicited in UA rings were augmented in presence of Eugenol (NP: 16.22%, P: 42.67%) or Curcumin (NP:21.23%, P:35.49%) or Nanocurcumin (NP:6.91%, P:34.88%). K+ vasorelaxation was inhibited in presence of Ouabain and Eugenol/ Curcumin/Nanocurcumin (Rmax: 6.11%, 9.18%, 4.11% in non-P, respectively) and (Rmax: 5.40%, 3.39%, 6.00% in P, respectively). The results indicated that (i) there is increased function of α1- Na+, K+-ATPase in UA of P goats (ii) Eugenol, Curcumin and Nano-curcumin differentially augmented the function and expression of α1 isoenzymes of sodium pump in UA of non-P and P goats. Thus, the polyphenols potentially activate α1 isoenzymes of Na+-K+-ATPase and could possibly be useful as therapeutic in hypertension during pregnancy
Thermodynamics, strange quark matter, and strange stars
Because of the mass density-dependence, an extra term should be added to the
expression of pressure. However, it should not appear in that of energy
according to both the general ensemble theory and basic thermodynamic
principle. We give a detail derivation of the thermodynamics with
density-dependent particle masses. With our recently determined quark mass
scaling, we study strange quark matter in this new thermodynamic treatment,
which still indicates a possible absolute stability as previously found.
However, the density behavior of the sound velocity is opposite to the previous
finding, but consistent with one of our recent publication. We have also
studied the structure of strange stars using the obtained equation of state.Comment: 6 pages, 6 PS figures, REVTeX styl
Mass formulas and thermodynamic treatment in the mass-density-dependent model of strange quark matter
The previous treatments for strange quark matter in the quark
mass-density-dependent model have unreasonable vacuum limits. We provide a
method to obtain the quark mass parametrizations and give a self-consistent
thermodynamic treatment which includes the MIT bag model as an extreme. In this
treatment, strange quark matter in bulk still has the possibility of absolute
stability. However, the lower density behavior of the sound velocity is
opposite to previous findings.Comment: Formatted in REVTeX 3.1, 5 pages, 3 figures, to appear in PRC6
Curvature energy effects on strange quark matter nucleation at finite density
We consider the effects of the curvature energy term on thermal strange quark
matter nucleation in dense neutron matter. Lower bounds on the temperature at
which this process can take place are given and compared to those without the
curvature term.Comment: PlainTex, 6 pp., IAG-USP Rep.5
Tissue Invasion by Entamoeba histolytica: Evidence of Genetic Selection and/or DNA Reorganization Events in Organ Tropism
Entamoeba histolytica infection may have various clinical manifestations. Nine out of ten E. histolytica infections remain asymptomatic, while the remainder become invasive and cause disease. The most common form of invasive infection is amebic diarrhea and colitis, whereas the most common extra-intestinal disease is amebic liver abscess. The underlying reasons for the different outcomes are unclear, but a recent study has shown that the parasite genotype is a contributor. To investigate this link further we have examined the genotypes of E. histolytica in stool- and liver abscess-derived samples from the same patients. Analysis of all 18 paired samples (16 from Bangladesh, one from the United States of America, and one from Italy) revealed that the intestinal and liver abscess amebae are genetically distinct. The results suggest either that E. histolytica subpopulations in the same infection show varying organ tropism, or that a DNA reorganization event takes place prior to or during metastasis from intestine to liver
Increased maternal TSH and decreased maternal FT4 are associated with a higher operative delivery rate in low-risk pregnancies: A prospective cohort study
Background: The increasing number of operative deliveries is a topic of major concern in modern obstetrics. Maternal thyroid function is of known influence on many obstetric parameters. Our objective was to investigate a possible relation between maternal thyroid function, and operative deliveries. Secondary aim was to explore whether thyroid function was related to specific reasons for operative deliveries. Methods: In this prospective cohort study, low-risk Caucasian women, pregnant of a single cephalic fetus were included. Women with known auto-immune disease, a pre-labour Caesarean section, induction of labour, breech presentation or preterm delivery were excluded. In all trimesters of pregnancy the thyroid function was assessed. Differences in mean TSH and FT4 were assessed using t-test. Mean TSH and FT4 levels for operative deliveries were determined by one way ANOVA. Repeated measurement analyses were performed (ANOVA), adjusting for BMI, partiy, maternal age and gestational age at delivery. Results: In total 872 women were included, of which 699 (80.2 %) had a spontaneous delivery. At 36 weeks gestation women who had an operative delivery had a significantly higher mean TSH (1.63mIU/L versus 1.46mIU/L, p = 0.025) and lower mean FT4 (12.9pmol/L versus 13.3pmol/L, p = 0.007)) compared to women who had a spontaneous delivery. Mean TSH was significantly higher (p = 0.026) and mean FT4 significantly lower (p = 0.030) throughout pregnancy for women with an operative delivery due to failure to progress in second stage of labour, compared to women with a spontaneous delivery or operative delivery for other reasons. Conclusion: Increased TSH and decreased FT4 seem to be associated with more operative vaginal deliveries and Caesarean sections. After adjusting for several confounders the association remained for operative deliveries due to failure to progress in second stage of labour, possibly to be explained by less efficient uterine action
R1507, an Anti-Insulin-Like Growth Factor-1 Receptor (IGF-1R) Antibody, and EWS/FLI-1 siRNA in Ewing's Sarcoma: Convergence at the IGF/IGFR/Akt Axis
A subset of patients with Ewing's sarcoma responds to anti-insulin-like growth factor-1 receptor (IGF-1R) antibodies. Mechanisms of sensitivity and resistance are unknown. We investigated whether an anti-IGF-1R antibody acts via a pathway that could also be suppressed by small interfering (si) RNA against the EWS/FLI-1 fusion protein, the hallmark of Ewing's sarcoma. The growth of two Ewing's sarcoma cell lines (TC-32 and TC-71) was inhibited by the fully human anti-IGF-1R antibody, R1507 (clonogenic and MTT assays). TC-32 and TC-71 cells express high levels of IGF-2, while RD-ES and A4573 Ewing's cell lines, which were less responsive to R1507 in our assays, express low or undetectable IGF-2, respectively. TC-71 cells also expressed high levels of IGF-1R, and R1507 decreased steady-state levels of this receptor by internalization/degradation, an effect which was associated with a decrease in p-IGF-1R, p-IRS-1, and p-Akt. EWS/FLI-1 siRNA also decreased p-Akt, due to its ability to increase IGF-BP3 levels and subsequently decrease IGF-1 and IGF-2 levels, thus inhibiting signaling through p-IGF-1R. This inhibition correlated with growth suppression and apoptosis. The attenuation of Akt activation was confirmed in TC-71 and HEK-293 (human embryonic kidney) cells by transfecting them with IGF-1R siRNA. We conclude that antibodies and siRNA to IGF-1R, as well as siRNA to EWS/FLI-1, act via intersecting IGF/IGF-1R signals that suppress a common point in this pathway, namely the phosphorylation of Akt
Global burden and strength of evidence for 88 risk factors in 204 countries and 811 subnational locations, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021
Background: Understanding the health consequences associated with exposure to risk factors is necessary to inform public health policy and practice. To systematically quantify the contributions of risk factor exposures to specific health outcomes, the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 aims to provide comprehensive estimates of exposure levels, relative health risks, and attributable burden of disease for 88 risk factors in 204 countries and territories and 811 subnational locations, from 1990 to 2021. Methods: The GBD 2021 risk factor analysis used data from 54 561 total distinct sources to produce epidemiological estimates for 88 risk factors and their associated health outcomes for a total of 631 risk–outcome pairs. Pairs were included on the basis of data-driven determination of a risk–outcome association. Age-sex-location-year-specific estimates were generated at global, regional, and national levels. Our approach followed the comparative risk assessment framework predicated on a causal web of hierarchically organised, potentially combinative, modifiable risks. Relative risks (RRs) of a given outcome occurring as a function of risk factor exposure were estimated separately for each risk–outcome pair, and summary exposure values (SEVs), representing risk-weighted exposure prevalence, and theoretical minimum risk exposure levels (TMRELs) were estimated for each risk factor. These estimates were used to calculate the population attributable fraction (PAF; ie, the proportional change in health risk that would occur if exposure to a risk factor were reduced to the TMREL). The product of PAFs and disease burden associated with a given outcome, measured in disability-adjusted life-years (DALYs), yielded measures of attributable burden (ie, the proportion of total disease burden attributable to a particular risk factor or combination of risk factors). Adjustments for mediation were applied to account for relationships involving risk factors that act indirectly on outcomes via intermediate risks. Attributable burden estimates were stratified by Socio-demographic Index (SDI) quintile and presented as counts, age-standardised rates, and rankings. To complement estimates of RR and attributable burden, newly developed burden of proof risk function (BPRF) methods were applied to yield supplementary, conservative interpretations of risk–outcome associations based on the consistency of underlying evidence, accounting for unexplained heterogeneity between input data from different studies. Estimates reported represent the mean value across 500 draws from the estimate's distribution, with 95% uncertainty intervals (UIs) calculated as the 2·5th and 97·5th percentile values across the draws. Findings: Among the specific risk factors analysed for this study, particulate matter air pollution was the leading contributor to the global disease burden in 2021, contributing 8·0% (95% UI 6·7–9·4) of total DALYs, followed by high systolic blood pressure (SBP; 7·8% [6·4–9·2]), smoking (5·7% [4·7–6·8]), low birthweight and short gestation (5·6% [4·8–6·3]), and high fasting plasma glucose (FPG; 5·4% [4·8–6·0]). For younger demographics (ie, those aged 0–4 years and 5–14 years), risks such as low birthweight and short gestation and unsafe water, sanitation, and handwashing (WaSH) were among the leading risk factors, while for older age groups, metabolic risks such as high SBP, high body-mass index (BMI), high FPG, and high LDL cholesterol had a greater impact. From 2000 to 2021, there was an observable shift in global health challenges, marked by a decline in the number of all-age DALYs broadly attributable to behavioural risks (decrease of 20·7% [13·9–27·7]) and environmental and occupational risks (decrease of 22·0% [15·5–28·8]), coupled with a 49·4% (42·3–56·9) increase in DALYs attributable to metabolic risks, all reflecting ageing populations and changing lifestyles on a global scale. Age-standardised global DALY rates attributable to high BMI and high FPG rose considerably (15·7% [9·9–21·7] for high BMI and 7·9% [3·3–12·9] for high FPG) over this period, with exposure to these risks increasing annually at rates of 1·8% (1·6–1·9) for high BMI and 1·3% (1·1–1·5) for high FPG. By contrast, the global risk-attributable burden and exposure to many other risk factors declined, notably for risks such as child growth failure and unsafe water source, with age-standardised attributable DALYs decreasing by 71·5% (64·4–78·8) for child growth failure and 66·3% (60·2–72·0) for unsafe water source. We separated risk factors into three groups according to trajectory over time: those with a decreasing attributable burden, due largely to declining risk exposure (eg, diet high in trans-fat and household air pollution) but also to proportionally smaller child and youth populations (eg, child and maternal malnutrition); those for which the burden increased moderately in spite of declining risk exposure, due largely to population ageing (eg, smoking); and those for which the burden increased considerably due to both increasing risk exposure and population ageing (eg, ambient particulate matter air pollution, high BMI, high FPG, and high SBP). Interpretation: Substantial progress has been made in reducing the global disease burden attributable to a range of risk factors, particularly those related to maternal and child health, WaSH, and household air pollution. Maintaining efforts to minimise the impact of these risk factors, especially in low SDI locations, is necessary to sustain progress. Successes in moderating the smoking-related burden by reducing risk exposure highlight the need to advance policies that reduce exposure to other leading risk factors such as ambient particulate matter air pollution and high SBP. Troubling increases in high FPG, high BMI, and other risk factors related to obesity and metabolic syndrome indicate an urgent need to identify and implement interventions
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