339 research outputs found
Twin jets as a potential distance detector
A preview study of using observational data of proper motions and Doppler
shifted velocities of twin-jets to determine the distance of sources inside and
outside our galaxy is made. We investigate the feasibility of this method by
studying the uncertainty of the distance caused by the uncertainties of the
measured quantities. It shows that, when the motion of components of the jet is
relativistic, then the uncertainty of the distance is within the same order of
the uncertainties of the measured values of proper motions and Doppler shifted
velocities. In particular, when assuming the pattern speed equals the flow
speed in the jet, for 10% uncertainties of the measured quantities, the
uncertainty of the distance caused by them would be well within 13%. With
current technique, this method is realizable. For the convenience of choosing
sources to observe, some sources as potential targets are also listed in this
paper.Comment: 11 page
Testing a new luminosity/redshift indicator for -ray bursts
We have tested a relative spectral lag (RSL) method suggested earlier as a
luminosity/redshift (or distance) estimator, using the generalized method by
Schaefer & Collazzi. We find the derivations from the luminosity/redshift-RSL
(L/R-RSL) relation are comparable with the corresponding observations. Applying
the luminosity-RSL relation to two different GRB samples, we find that there
exist no violators from the generalized test, namely the Nakar & Piran test and
Li test. We also find that about 36 per cent of Schaefer's sample are outliers
for the L/R-RSL relation within 1 confidence level, but no violators at
3 level within the current precision of L/R-RSL relation. An analysis
of several potential outliers for other luminosity relations shows they can
match the L/R-RSL relation well within an acceptable uncertainty. All the
coincident results seem to suggest that this relation could be a potential tool
for cosmological study.Comment: 7 pages, 6 figures and 1 table; Comments are welcom
Protective Effects of Squid Ink Extract Towards Hemopoietic Injuries Induced by Cyclophosphamine
To investigate the protective effects of squid ink in chemotherapy, BALB/c mice were used as animal models of injuries induced by cyclophosphamine, a well known chemotherapeutic drug. The mice were randomly divided into five groups with the same number of males and females in each group. At the end of the experiment, animals were sacrificed to investigate organ indexes and antioxidant ability of the spleen, peripheral blood profile and quantities of bone marrow nucleated cells. Results showed that the hemopoietic function of mice was injured by cyclophosphamine, as indicated by decreases of contents of erythrocytes, leukocytes, hemoglobin and bone marrow nucleated cells (P<0.01), while platelets were not affected (P>0.05), as well as modification of organ indexes (P<0.05) and spleen antioxidant ability (P<0.05 or P<0.01), whereas sepia extract markedly increased the levels of erythrocytes, leukocytes, hemoglobin and bone marrow nucleated cells (P<0.01), but not platelets (P>0.05), and reversed the effects of cyclophosphamine on organ indexes and antioxidant ability of spleen (P<0.01 or P<0.05). In addition, squid ink extract did not change marrow hemopoiesis but improved the antioxidant ability of spleen in the animals. The data suggest that squid ink extract can protect the hemopoietic system from chemotherapeutic injury and could be employed to develop cell-protective drugs for use in clinical treatment of tumours
3,6-Diiodo-9H-carbazole
In the title compound, C12H7I2N, the tricyclic aromatic ring system is essentially planar, with an r.m.s. deviation of 0.0272 Å. The two I atoms are marginally out of plane, with the C—I bonds angled at 3.9 (2) and 1.1 (2)° with respect to the planes of their respective benzene rings, above and below the plane of the carbazole ring system. No classical hydrogen bonds are observed in the crystal structure
Metabolic syndrome and risk of subclinical hypothyroidism: a systematic review and meta-analysis
BackgroundSubclinical hypothyroidism (SCH) is a common endocrine subclinical disorder, the main adverse consequences of which are the development of clinical hypothyroidism and the promotion of ischemic heart disease. Metabolic syndrome (MetS) is a collection of metabolic problems. The goal of this meta-analysis was to evaluate the relationship between MetS and SCH.MethodsSuitable publications were identified using PubMed, Embase, and the Cochrane Library. The meta-analysis included only studies in English that reported odds ratio (OR) data for MetS and SCH. Two researchers combined data using a random-effects model. OR and 95% confidence intervals (CIs) were used to present the results.ResultsMetS was associated with an elevated risk of developing SCH (OR 2.56, 95% CI 1.44–4.55). However, the individual components of MetS were not associated with the risk of SCH. Subgroup analysis revealed that different definitions of MetS had varying effects on SCH. Sensitivity analysis confirmed that our results were robust.ConclusionsThis meta-analysis indicates that patients with MetS have an increased risk of SCH, while there is no significant association between the five individual components of MetS and the risk of SCH.Systematic review registrationhttps://www.crd.york.ac.uk/PROSPERO/, identifier CRD42023454415
Correlations between various hardness ratios of gamma-ray bursts
We study correlations between various hardness ratios of gamma-ray bursts
(GRBs) and investigate if there are any differences between the two classes of
the objects in the distributions of the ratios. The results suggest that,
statistically, the slope of the higher part of the spectrum of the long
duration bursts has nothing to do with that of the lower part; emissions at
higher energy bands from the bursts of both short and long duration classes
must be significantly different for different sources, while radiations at
lower energy bands of the objects are relatively similar; the spectrum of the
short duration bursts must be harder than that of the long duration bursts,
confirming what the well-known hardness-duration correlation reveals; the
profiles of the spectra between the long duration bursts must be more similar
than that between the short duration bursts. The long duration bursts would
share more common properties than the short duration bursts. A possible
interpretation is proposed with the concept of the Doppler boosting in the
relativistic beaming model in AGNs.Comment: 38 pages, 30 figure
Testosterone-mediated endocrine function and TH1/TH2 cytokine balance after prenatal exposure to perfluorooctane sulfonate: by sex status
Little information exists about the evaluation of potential developmental immunotoxicity induced by perfluorooctane sulfonate (PFOS), a synthetic persistent and increasingly ubiquitous environmental contaminant. To assess potential sex-specific impacts of PFOS on immunological health in the offspring, using male and female C57BL/6 mice, pups were evaluated for developmental immunotoxic effects after maternal oral exposure to PFOS (0.1, 1.0 and 5.0 mg PFOS/kg/day) during Gestational Days 1—17. Spontaneous TH1/TH2-type cytokines, serum levels of testosterone and estradiol were evaluated in F1 pups at four and eight weeks of age. The study showed that male pups were more sensitive to the effects of PFOS than female pups. At eight weeks of age, an imbalance in TH1/TH2-type cytokines with excess TH2 cytokines (IL-4) was found only in male pups. As for hormone levels, PFOS treatment in utero significantly decreased serum testosterone levels and increased estradiol levels only in male pups, and a significant interaction between sex and PFOS was observed for serum testosterone at both four weeks of age (pinteraction = 0.0049) and eight weeks of age (pinteraction = 0.0227) and for estradiol alternation at four weeks of age (pinteraction = 0.0351). In conclusion, testosterone-mediated endocrine function may be partially involved in the TH1/TH2 imbalance induced by PFOS, and these deficits are detectable among both young and adult mice and may affect males more than females
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