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1.
Phys Rev Lett ; 127(17): 171801, 2021 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-34739288

RESUMO

Using a dataset of 6.32 fb^{-1} of e^{+}e^{-} annihilation data collected with the BESIII detector at center-of-mass energies between 4178 and 4226 MeV, we have measured the absolute branching fraction of the leptonic decay D_{s}^{+}→τ^{+}ν_{τ} via τ^{+}→e^{+}ν_{e}ν[over ¯]_{τ}, and find B_{D_{s}^{+}→τ^{+}ν_{τ}}=(5.27±0.10±0.12)×10^{-2}, where the first uncertainty is statistical and the second is systematic. The precision is improved by a factor of 2 compared to the previous best measurement. Combining with f_{D_{s}^{+}} from lattice quantum chromodynamics calculations or the |V_{cs}| from the CKMfitter group, we extract |V_{cs}|=0.978±0.009±0.012 and f_{D_{s}^{+}}=(251.1±2.4±3.0) MeV, respectively. Combining our result with the world averages of B_{D_{s}^{+}→τ^{+}ν_{τ}} and B_{D_{s}^{+}→µ^{+}ν_{µ}}, we obtain the ratio of the branching fractions B_{D_{s}^{+}→τ^{+}ν_{τ}}/B_{D_{s}^{+}→µ^{+}ν_{µ}}=9.72±0.37, which is consistent with the standard model prediction of lepton flavor universality.

2.
Phys Rev Lett ; 127(13): 131801, 2021 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-34623854

RESUMO

Using 2.93 fb^{-1} of e^{+}e^{-} collision data taken with the BESIII detector at a center-of-mass energy of 3.773 GeV, the observation of the D^{0}→K_{1}(1270)^{-}e^{+}ν_{e} semileptonic decay is presented. The statistical significance of the decay D^{0}→K_{1}(1270)^{-}e^{+}ν_{e} is greater than 10σ. The branching fraction of D^{0}→K_{1}(1270)^{-}e^{+}ν_{e} is measured to be (1.09±0.13_{-0.16}^{+0.09}±0.12)×10^{-3}. Here, the first uncertainty is statistical, the second is systematic, and the third originates from the assumed branching fraction of K_{1}(1270)^{-}→K^{-}π^{+}π^{-}. The fraction of longitudinal polarization in D^{0}→K_{1}(1270)^{-}e^{+}ν_{e} is determined for the first time to be 0.50±0.19_{stat}±0.08_{syst}.

3.
Phys Rev Lett ; 127(12): 121802, 2021 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-34597097

RESUMO

The absolute branching fraction of Λ→pµ^{-}ν[over ¯]_{µ} is reported for the first time based on an e^{+}e^{-} annihilation sample of 10×10^{9} J/ψ events collected with the BESIII detector at sqrt[s]=3.097 GeV. The branching fraction is determined to be B(Λ→pµ^{-}ν[over ¯]_{µ})=[1.48±0.21(stat)±0.08(syst)]×10^{-4}, which is improved by about 30% in precision over the previous indirect measurements. Combining this result with the world average of B(Λ→pe^{-}ν[over ¯]_{e}), we obtain the ratio {[Γ(Λ→pµ^{-}ν[over ¯]_{µ})]/[Γ(Λ→pe^{-}ν[over ¯]_{e})]} to be 0.178±0.028, which agrees with the standard model prediction assuming lepton flavor universality. The asymmetry of the branching fractions of Λ→pµ^{-}ν[over ¯]_{µ} and Λ[over ¯]→p[over ¯]µ^{+}ν_{µ} is also determined, and no evidence for CP violation is found.

4.
Phys Rev Lett ; 127(8): 082002, 2021 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-34477419

RESUMO

We report a measurement of the observed cross sections of e^{+}e^{-}→J/ψX based on 3.21 fb^{-1} of data accumulated at energies from 3.645 to 3.891 GeV with the BESIII detector operated at the BEPCII collider. In analysis of the cross sections, we measured the decay branching fractions of B(ψ(3686)→J/ψX)=(64.4±0.6±1.6)% and B(ψ(3770)→J/ψX)=(0.5±0.2±0.1)% for the first time. The energy-dependent line shape of these cross sections cannot be well described by two Breit-Wigner (BW) amplitudes of the expected decays ψ(3686)→J/ψX and ψ(3770)→J/ψX. Instead, it can be better described with one more BW amplitude of the decay R(3760)→J/ψX. Under this assumption, we extracted the R(3760) mass M_{R(3760)}=3766.2±3.8±0.4 MeV/c^{2} , total width Γ_{R(3760)}^{tot}=22.2±5.9±1.4 MeV, and product of leptonic width and decay branching fraction Γ_{R(3760)}^{ee}B[R(3760)→J/ψX]=(79.4±85.5±11.7) eV. The significance of the R(3760) is 5.3σ. The first uncertainties of these measured quantities are from fits to the cross sections and second systematic.

5.
Phys Rev Lett ; 126(24): 241103, 2021 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-34213924

RESUMO

We report the discovery of an extended very-high-energy (VHE) gamma-ray source around the location of the middle-aged (207.8 kyr) pulsar PSR J0622+3749 with the Large High-Altitude Air Shower Observatory (LHAASO). The source is detected with a significance of 8.2σ for E>25 TeV assuming a Gaussian template. The best-fit location is (right ascension, declination) =(95.47°±0.11°,37.92°±0.09°), and the extension is 0.40°±0.07°. The energy spectrum can be described by a power-law spectrum with an index of -2.92±0.17_{stat}±0.02_{sys}. No clear extended multiwavelength counterpart of the LHAASO source has been found from the radio to sub-TeV bands. The LHAASO observations are consistent with the scenario that VHE electrons escaped from the pulsar, diffused in the interstellar medium, and scattered the interstellar radiation field. If interpreted as the pulsar halo scenario, the diffusion coefficient, inferred for electrons with median energies of ∼160 TeV, is consistent with those obtained from the extended halos around Geminga and Monogem and much smaller than that derived from cosmic ray secondaries. The LHAASO discovery of this source thus likely enriches the class of so-called pulsar halos and confirms that high-energy particles generally diffuse very slowly in the disturbed medium around pulsars.

6.
Science ; 373(6553): 425-430, 2021 07 23.
Artigo em Inglês | MEDLINE | ID: mdl-34261813

RESUMO

The Crab Nebula is a bright source of gamma rays powered by the Crab Pulsar's rotational energy through the formation and termination of a relativistic electron-positron wind. We report the detection of gamma rays from this source with energies from 5 × 10-4 to 1.1 peta-electron volts with a spectrum showing gradual steepening over three energy decades. The ultrahigh-energy photons imply the presence of a peta-electron volt electron accelerator (a pevatron) in the nebula, with an acceleration rate exceeding 15% of the theoretical limit. We constrain the pevatron's size between 0.025 and 0.1 parsecs and the magnetic field to ≈110 microgauss. The production rate of peta-electron volt electrons, 2.5 × 1036 ergs per second, constitutes 0.5% of the pulsar spin-down luminosity, although we cannot exclude a contribution of peta-electron volt protons to the production of the highest-energy gamma rays.

7.
Zhonghua Yu Fang Yi Xue Za Zhi ; 55(5): 646-652, 2021 May 06.
Artigo em Chinês | MEDLINE | ID: mdl-34034406

RESUMO

Objective: To investigate the association of thallium exposure during pregnancy with pregnant blood pressure changing and hypertensive disorder complicating pregnancy(HDCP). Methods: A total of 3 240 pregnant women who had establish maternal health care manual in Ma'anshan Maternal and Child Health-Care Hospital and met the inclusion and exclusion criteria were included in this study between May 2013 and September 2014.We collected their general demographic characteristics and blood pressure through questionnaire and medical records. Meanwhile we measured serum thallium concentrations by experimental technology. We use multiple logistic regression to analyze the association between thallium exposure during pregnancy and HDCP. Mixed linear model were used to analyze the association between thallium concentration and maternal systolic blood pressure (SBP) or diastolic blood pressure(DBP) in different trimesters Results: The age of 3 240 pregnant woman was (26.61±3.64) years, and the detection rate of HDCP was 5.9%(191).The median (P25, P75) of thallium concentrations in first trimester, second trimester and third trimester were 62.96 (50.79, 77.04), 62.19 (50.87, 75.26), 48.84 (38.00, 66.00) ng/L, respectively. Multiple logistic regression results suggested after adjusting various confounding factors, the risk of HDCP in pregnant women with high concentrations of thallium (>77.04 ng/L) in the first trimester is 1.75 (95%CI:1.01-3.03) times higher than which with low concentrations(<50.82 ng/L). Mixed linear model results suggested there are positive correlation between thallium concentrations with maternal DBP in first trimester (ß=1.12, 95%CI: 0.39-1.85). Conclusion: Exposure to high levels of thallium during first trimester may increase the risk of HDCP, and the exposure of thallium may be effective to DBP of pregnant.


Assuntos
Hipertensão , Tálio , Adulto , Pressão Sanguínea , Criança , Feminino , Humanos , Exposição Materna , Gravidez , Segundo Trimestre da Gravidez , Terceiro Trimestre da Gravidez , Adulto Jovem
8.
Nature ; 594(7861): 33-36, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-34002091

RESUMO

The extension of the cosmic-ray spectrum beyond 1 petaelectronvolt (PeV; 1015 electronvolts) indicates the existence of the so-called PeVatrons-cosmic-ray factories that accelerate particles to PeV energies. We need to locate and identify such objects to find the origin of Galactic cosmic rays1. The principal signature of both electron and proton PeVatrons is ultrahigh-energy (exceeding 100 TeV) γ radiation. Evidence of the presence of a proton PeVatron has been found in the Galactic Centre, according to the detection of a hard-spectrum radiation extending to 0.04 PeV (ref. 2). Although γ-rays with energies slightly higher than 0.1 PeV have been reported from a few objects in the Galactic plane3-6, unbiased identification and in-depth exploration of PeVatrons requires detection of γ-rays with energies well above 0.1 PeV. Here we report the detection of more than 530 photons at energies above 100 teraelectronvolts and up to 1.4 PeV from 12 ultrahigh-energy γ-ray sources with a statistical significance greater than seven standard deviations. Despite having several potential counterparts in their proximity, including pulsar wind nebulae, supernova remnants and star-forming regions, the PeVatrons responsible for the ultrahigh-energy γ-rays have not yet been firmly localized and identified (except for the Crab Nebula), leaving open the origin of these extreme accelerators.

9.
Zhonghua Xue Ye Xue Za Zhi ; 42(3): 217-223, 2021 Mar 14.
Artigo em Chinês | MEDLINE | ID: mdl-33910307

RESUMO

Objective: To prepare a novel tri-specific T cell engager (19TriTE) targeting CD19 antigen, and to investigate its immunotherapeutic effect on CD19-positive hematological malignancies. Methods: 19TriTE was constructed by molecular cloning technology and successfully expressed through the eukaryotic expressing system. The effects of 19TriTE on the proliferation and activation of T cells, as well as the specific cytotoxicity against CD19 positive tumor cell lines were verified. Results: ①19TriTE expressing plasmid was constructed and successfully expressed through the eukaryotic expressing system. ②19TriTE can specifically bind to T cells and Nalm6 cells, with equilibrium dissociation constants of 19.21 nmol/L and 11.67 nmol/L, respectively. ③The expression rates of CD69 positive T cells and CD25 positive T cells were 35.4% and 49.8% respectively, when 2 nmol/L 19TriTE were added in the co-culture system, which were significantly higher than those in the control group. ④19TriTE can significantly promote the proliferation of T cells. The absolute count of T cells expanded from the initial one million to 74 million with an 74 fold increase at the concentration of 1 nmol/L on day 12. ⑤19TriTE can significantly mediate T cells killing of CD19 positive target cells in a dose-dependent manner. At the concentration of 10 nmol/L, the target cells lysis reached 50%. ⑥Degranulation experiment verified that 19TriTE can activate T cells in the presence of CD19 positive target cells, and the activation of T cells positively correlated with the dose of 19TriTE. ⑦When 19TriTE fusion protein co-cultured with T cells and target cells overexpression RFP and luciferase genes respectively, 19TriTE can notably mediate T cells killing of CD19 positive target cells through fluorescent microscope or bioluminescence imaging technology. Conclusion: In this study, we successfully constructed and expressed 19TriTE fusion protein and verified that it can effectively activate T cells and promote their proliferation in vitro. At the same time, it can bind to CD19 positive target cells and T cells, as well as enhance T cells anti-leukemia effect in vitro, providing the foundation for further clinical research.


Assuntos
Antígenos CD19 , Leucemia , Linhagem Celular Tumoral , Humanos , Imunoterapia Adotiva , Linfócitos T
10.
Phys Rev Lett ; 126(10): 102001, 2021 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-33784133

RESUMO

We report a study of the processes of e^{+}e^{-}→K^{+}D_{s}^{-}D^{*0} and K^{+}D_{s}^{*-}D^{0} based on e^{+}e^{-} annihilation samples collected with the BESIII detector operating at BEPCII at five center-of-mass energies ranging from 4.628 to 4.698 GeV with a total integrated luminosity of 3.7 fb^{-1}. An excess of events over the known contributions of the conventional charmed mesons is observed near the D_{s}^{-}D^{*0} and D_{s}^{*-}D^{0} mass thresholds in the K^{+} recoil-mass spectrum for events collected at sqrt[s]=4.681 GeV. The structure matches a mass-dependent-width Breit-Wigner line shape, whose pole mass and width are determined as (3982.5_{-2.6}^{+1.8}±2.1) MeV/c^{2} and (12.8_{-4.4}^{+5.3}±3.0) MeV, respectively. The first uncertainties are statistical and the second are systematic. The significance of the resonance hypothesis is estimated to be 5.3 σ over the contributions only from the conventional charmed mesons. This is the first candidate for a charged hidden-charm tetraquark with strangeness, decaying into D_{s}^{-}D^{*0} and D_{s}^{*-}D^{0}. However, the properties of the excess need further exploration with more statistics.

11.
Phys Rev Lett ; 126(9): 092002, 2021 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-33750166

RESUMO

We present an analysis of the process ψ(3686)→Ω^{-}Ω[over ¯]^{+} (Ω^{-}→K^{-}Λ, Ω[over ¯]^{+}→K^{+}Λ[over ¯], Λ→pπ^{-}, Λ[over ¯]→p[over ¯]π^{+}) based on a dataset of 448×10^{6} ψ(3686) decays collected with the BESIII detector at the BEPCII electron-positron collider. The helicity amplitudes for the process ψ(3686)→Ω^{-}Ω[over ¯]^{+} and the decay parameters of the subsequent decay Ω^{-}→K^{-}Λ (Ω[over ¯]^{+}→K^{+}Λ[over ¯]) are measured for the first time by a fit to the angular distribution of the complete decay chain, and the spin of the Ω^{-} is determined to be 3/2 for the first time since its discovery more than 50 years ago.

12.
Zhonghua Yu Fang Yi Xue Za Zhi ; 55(1): 72-77, 2021 Jan 06.
Artigo em Chinês | MEDLINE | ID: mdl-33455135

RESUMO

Objective: To understand the epidemiological and pathogenic characteristics of Legionella in artificial water environment of public places in Shanghai from 2011 to 2018, and to provide scientific basis for the prevention and control of Legionellosis. Methods: A total of 4 817 samples of artificial water environment were collected from 31 public places in Huangpu, Jing'an, Xuhui and Songjiang districts of Shanghai from 2011 to 2108. Epidemiological characteristics of the collected years and months, regional and site types, and sample types were analyzed. After treatment, culture and isolation of the collected water samples, the positive samples were analyzed for Legionella typing characteristics. Results: The positive rate of Legionella pneumophila was 21.57% (1 039/4 817), of which 96.25% (1 000/1 039) was single type, 84.31% (876/1 039) was Legionella pneumophila type 1, followed by Legionella pneumophila type 7 and 6, which accounted for 4.72% (49/1 039) and 3.75% (39/1 039), respectively, and 29 (29/1 039) were multi-type positive. Further typing. From May to October, the highest positive rates were found in July and August, 27.61%(222/804)and 28.61% (230/804)respectively. There were significant differences between different months (P<0.001); the highest positive rates were found in central air-conditioning cooling water and chilled water (32.40%) and there were significant differences among different water samples (P<0.001). Legionella pneumophila type 1, type 7 and type 6 were the main diversity distribution characteristics in artificial water environment of different regions, different time, different places and different types of public places. Legionella pneumophila type 1 accounted for the highest proportion, and the proportion of positive samples under different epidemiological characteristics was more than 71.64%. Conclusion: There is relatively serious pollution of Legionella pneumophila type 1 in the artificial water environment of public places in Shanghai. It is necessary to strengthen the disinfection of cooling water/freezing water of central air conditioning in public places in July and August every year.


Assuntos
Legionella pneumophila , Legionella , China , Humanos , Água , Microbiologia da Água
13.
Eur Rev Med Pharmacol Sci ; 25(1): 301-312, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33506919

RESUMO

OBJECTIVE: Coronary artery disease (CAD) is the main cause of mortality worldwide. How stable coronary artery disease (SCAD) progresses to acute myocardial infarction (AMI) is not known. This study was aimed to explore the differentially expressed genes (DEGs) and pathways involved in the progression of SCAD to AMI. MATERIALS AND METHODS: Publicly available gene-expression profiles (GSE71226, GSE97320, GSE66360) were downloaded from the Gene Expression Omnibus (GEO) database and integrated to identify DEGs. The GSE59867 dataset was further used to verify the result of screened DEGs. Functional-enrichment analyses, protein-protein interaction network, microRNA-transcription factor (TF)-mRNA regulatory network, and drug-gene network were visualized. RESULTS: Sixty common DEGs (CDEGs) were screened between the SCAD-Control group and AMI-Control group in the integrated dataset. Four upregulated DEGs were selected from GSE59867. Twenty hub genes were discovered, and three significant modules were constructed in the PPI network. The intersection of functional and pathway-enrichment analyses of 60 CDEGs and the module DEGs indicated that they were mainly involved in "inflammatory response", "immune response", and "cytokine-cytokine receptor interaction". A miRNA-TF-mRNA regulatory network comprised 87 miRNAs, 16 upregulated target DEGs and 7 TFs. CONCLUSIONS: We identified several important genes and miRNAs involved in the progression of SCAD to AMI: platelet activating factor receptor (PTAFR), aquaoporin-9 (AQP9), toll-like receptor-4 (TLR4), human constitutive androstane receptor-3 (HCAR3), leucine-rich-α2 glycoprotein-1 (LRG1), mothers Against Decapentaplegic Homolog 4 (SMAD4) and miRNA-149-5p, miRNA-6778-3p, and miRNA-520a-3p. Inflammation and the immune response had important roles in the progression from SCAD to AMI.


Assuntos
Biologia Computacional , Doença da Artéria Coronariana/metabolismo , Infarto do Miocárdio/metabolismo , Doença Aguda , Aquaporinas/genética , Aquaporinas/imunologia , Doença da Artéria Coronariana/genética , Doença da Artéria Coronariana/patologia , Glicoproteínas/genética , Glicoproteínas/imunologia , Humanos , MicroRNAs/genética , MicroRNAs/imunologia , Infarto do Miocárdio/genética , Infarto do Miocárdio/patologia , Glicoproteínas da Membrana de Plaquetas/genética , Glicoproteínas da Membrana de Plaquetas/metabolismo , Mapas de Interação de Proteínas , Receptores Acoplados a Proteínas G/genética , Receptores Acoplados a Proteínas G/imunologia , Receptores Acoplados a Proteínas G/metabolismo , Receptores Nicotínicos/genética , Receptores Nicotínicos/imunologia , Proteína Smad4/genética , Proteína Smad4/imunologia , Receptor 4 Toll-Like/genética , Receptor 4 Toll-Like/imunologia
14.
Eur Rev Med Pharmacol Sci ; 24(21): 10920, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-33215404

RESUMO

The article "LncRNA DLEU1 accelerates the malignant progression of clear cell renal cell carcinoma via regulating miRNA-194-5p, by G.-Z. He, S.-Y. Yu, Q.-P. Zhou, M.-L. Chen, Y.-W. Zhang, Y. Zheng, Z.-B. Zhang, Z.-Y. Han, J. Yu, published in Eur Rev Med Pharmacol Sci 2019; 23 (24): 10691-10698-DOI: 10.26355/eurrev_201912_19768-PMID 31858537" has been withdrawn from the authors. The Publisher apologizes for any inconvenience this may cause. https://www.europeanreview.org/article/19768.

15.
Phys Rev Lett ; 125(14): 141802, 2020 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-33064551

RESUMO

Using 2.93 fb^{-1} of e^{+}e^{-} collision data collected at a center-of-mass energy of 3.773 GeV with the BESIII detector, the first observation of the doubly Cabibbo-suppressed decay D^{+}→K^{+}π^{+}π^{-}π^{0} is reported. After removing decays that contain narrow intermediate resonances, including D^{+}→K^{+}η, D^{+}→K^{+}ω, and D^{+}→K^{+}ϕ, the branching fraction of the decay D^{+}→K^{+}π^{+}π^{-}π^{0} is measured to be (1.13±0.08_{stat}±0.03_{syst})×10^{-3}. The ratio of branching fractions of D^{+}→K^{+}π^{+}π^{-}π^{0} over D^{+}→K^{-}π^{+}π^{+}π^{0} is found to be (1.81±0.15)%, which corresponds to (6.28±0.52)tan^{4}θ_{C}, where θ_{C} is the Cabibbo mixing angle. This ratio is significantly larger than the corresponding ratios for other doubly Cabibbo-suppressed decays. The asymmetry of the branching fractions of charge-conjugated decays D^{±}→K^{±}π^{±}π^{∓}π^{0} is also determined, and no evidence for CP violation is found. In addition, the first evidence for the D^{+}→K^{+}ω decay, with a statistical significance of 3.3σ, is presented and the branching fraction is measured to be B(D^{+}→K^{+}ω)=(5.7_{-2.1}^{+2.5}_{stat}±0.2_{syst})×10^{-5}.

16.
Zhonghua Liu Xing Bing Xue Za Zhi ; 41(8): 1303-1307, 2020 Aug 10.
Artigo em Chinês | MEDLINE | ID: mdl-32867440

RESUMO

Objective: To examine the relationship between pre-pregnancy BMI, gestational diabetes (GDM) and different indicators of childhood obesity at the age of 4. Methods: Based on Ma'anshan Birth Cohort Study, singleton children who were born in Ma'anshan of Anhui province from October 2013 to April 2015, were followed for 4 years, consecutively. During the first questionnaire survey, data including pre-pregnancy weight, height and socio-demography were collected. During 24-28 week of gestation, 75 g oral glucose tolerance test was conducted for them. Childhood height, weight, waist circumference and body composition were measured at the age of 4. Comparisons between groups were performed using chi-square test, analysis of variance or t-test. The relationship between pre-pregnancy overweight/obesity, GDM and childhood obesity-related characteristics were analyzed by logistic regression model and generalized linear model analysis. Results: The prevalence rates of overweight and obesity in children at the age of 4 were 13.08% and 6.03%, respectively. After adjustment for characteristics related to mothers and their children, significantly increased risk of obesity (OR=3.27, 95%CI: 2.15-4.98), larger waist circumference (OR=2.32, 95%CI: 1.72-3.14) and higher waist-to-weight ratio (OR=2.29, 95%CI: 1.73-3.02) were seen in the offspring of women with pre-pregnancy overweight/obesity. Body composition (skeletal muscle, body fat, body fat percentage) of the offspring were strongly correlated with pre-pregnancy overweight/obesity of the mothers (P<0.05). Maternal GDM was associated with higher risk of childhood obesity (OR=1.78, 95%CI: 1.14-2.79), on mothers without GDM during pregnancy. However, neither larger waist circumference, or higher waist-to-weight ratio seemed to increase the risk. Moreover, maternal GDM was not associated with body composition measures (skeletal muscle, body fat, body fat percentage). Conclusion: Pre-pregnancy BMI and maternal GDM were independent risk factors for obesity in 4-year-old children, and pre-pregnancy BMI was correlated with various indicators of body composition in children.


Assuntos
Índice de Massa Corporal , Diabetes Gestacional/epidemiologia , Obesidade Pediátrica/epidemiologia , Pré-Escolar , China/epidemiologia , Feminino , Humanos , Gravidez , Estudos Prospectivos , Fatores de Risco
17.
Artigo em Chinês | MEDLINE | ID: mdl-32746570

RESUMO

Objective: To study the characteristics of the lens turbidity after long-term exposure to low intensity 635nm laser. Methods: Cluster sampling method was adopted to select 812 employees in a laser leveler workshop in a city of Guangdong Province from January 2014 to December 2018. They were divided into the control group, diffuse reflection (DR) group and direct vision (DV) group for retrospective observation and analysis of lens turbidity. The laser irradiation intensity of each group was investigated, the position and shape of lens opacity were analyzed, and the influencing factors were statistically analyzed with the repeated measurement data of dichotomy. Results: The laser irradiance and radiant exposure of DV group were between 0.72×10(-4) and 9.92×10(-4) mW/cm(2) and between 2.61×10(-2) and 1.53 J/cm(2), respectively. The subjects were mainly diagnosed with lens turbidity lesion, especially for the DV group. Most of lesions occurred in the pole and periphery of the anterior cortex. The lesions exhibited multipoint patterns with greyish white color. The turbidity rates in DV group (before work and work for 1, 2, 3 years) were 0%, 1.99% (8/402) , 4.98% (20/402) and 6.72% (27/402) , respectively, in the order of observation points. The statistical analysis of single factor effect showed that the turbidity rate was higher in DV group and higher in the second year in the DV group (P<0.01) . Multi-factor analysis of the laser effect on the lens showed that the main effect between groups, between the observation point were statistically significant (P<0.05) , but no statistical significance in the interaction between group×observation points (P>0.05) . Conclusion: Lens turbidity lesion can be caused by long-term exposure to low intensity 635 nm laser, so the product safety classification should be strictly strengthened. It is necessary to strengthen the protection of laser photochemical damage in the production process.


Assuntos
Catarata , Lasers , Cristalino , Exposição Ocupacional , Humanos , Estudos Retrospectivos
18.
Phys Rev Lett ; 125(5): 052004, 2020 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-32794879

RESUMO

From 1310.6×10^{6} J/ψ and 448.1×10^{6} ψ(3686) events collected with the BESIII experiment, we report the first observation of Σ^{+} and Σ[over ¯]^{-} spin polarization in e^{+}e^{-}→J/ψ[ψ(3686)]→Σ^{+}Σ[over ¯]^{-} decays. The relative phases of the form factors ΔΦ have been measured to be (-15.5±0.7±0.5)° and (21.7±4.0±0.8)° with J/ψ and ψ(3686) data, respectively. The nonzero value of ΔΦ allows for a direct and simultaneous measurement of the decay asymmetry parameters of Σ^{+}→pπ^{0}(α_{0}=-0.998±0.037±0.009) and Σ[over ¯]^{-}→p[over ¯]π^{0}(α[over ¯]_{0}=0.990±0.037±0.011), the latter value being determined for the first time. The average decay asymmetry, (α_{0}-α[over ¯]_{0})/2, is calculated to be -0.994±0.004±0.002. The CP asymmetry A_{CP,Σ}=(α_{0}+α[over ¯]_{0})/(α_{0}-α[over ¯]_{0})=-0.004±0.037±0.010 is extracted for the first time, and is found to be consistent with CP conservation.

19.
Phys Rev Lett ; 124(23): 231801, 2020 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-32603168

RESUMO

By analyzing a data sample corresponding to an integrated luminosity of 2.93 fb^{-1} collected at a center-of-mass energy of 3.773 GeV with the BESIII detector, we measure for the first time the absolute branching fraction of the D^{+}→ηµ^{+}ν_{µ} decay to be B_{D^{+}→ηµ^{+}ν_{µ}}=(10.4±1.0_{stat}±0.5_{syst})×10^{-4}. Using the world averaged value of B_{D^{+}→ηe^{+}ν_{e}}, the ratio of the two branching fractions is determined to be B_{D^{+}→ηµ^{+}ν_{µ}}/B_{D^{+}→ηe^{+}ν_{e}}=0.91±0.13_{(stat+syst)}, which agrees with the theoretical expectation of lepton flavor universality within uncertainty. By studying the differential decay rates in five four-momentum transfer intervals, we obtain the product of the hadronic form factor f_{+}^{η}(0) and the c→d Cabibbo-Kobayashi-Maskawa matrix element |V_{cd}| to be f_{+}^{η}(0)|V_{cd}|=0.087±0.008_{stat}±0.002_{syst}. Taking the input of |V_{cd}| from the global fit in the standard model, we determine f_{+}^{η}(0)=0.39±0.04_{stat}±0.01_{syst}. On the other hand, using the value of f_{+}^{η}(0) calculated in theory, we find |V_{cd}|=0.242±0.022_{stat}±0.006_{syst}±0.033_{theory}.

20.
Phys Rev Lett ; 124(24): 241802, 2020 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-32639796

RESUMO

We report the most precise measurements to date of the strong-phase parameters between D^{0} and D[over ¯]^{0} decays to K_{S,L}^{0}π^{+}π^{-} using a sample of 2.93 fb^{-1} of e^{+}e^{-} annihilation data collected at a center-of-mass energy of 3.773 GeV with the BESIII detector at the BEPCII collider. Our results provide the key inputs for a binned model-independent determination of the Cabibbo-Kobayashi-Maskawa angle γ/ϕ_{3} with B decays. Using our results, the decay model sensitivity to the γ/ϕ_{3} measurement is expected to be between 0.7° and 1.2°, approximately a factor of three smaller than that achievable with previous measurements, based on the studies of the simulated data. The improved precision of this work ensures that measurements of γ/ϕ_{3} will not be limited by knowledge of strong phases for the next decade. Furthermore, our results provide critical input for other flavor-physics investigations, including charm mixing, other measurements of CP violation, and the measurement of strong-phase parameters for other D-decay modes.

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