Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 203
Filtrar
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(20): 201102, 2021 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-34110215

RESUMO

The measurement of the energy spectrum of cosmic ray helium nuclei from 70 GeV to 80 TeV using 4.5 years of data recorded by the Dark Matter Particle Explorer (DAMPE) is reported in this work. A hardening of the spectrum is observed at an energy of about 1.3 TeV, similar to previous observations. In addition, a spectral softening at about 34 TeV is revealed for the first time with large statistics and well controlled systematic uncertainties, with an overall significance of 4.3σ. The DAMPE spectral measurements of both cosmic protons and helium nuclei suggest a particle charge dependent softening energy, although with current uncertainties a dependence on the number of nucleons cannot be ruled out.

6.
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.

7.
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.

8.
Zhonghua Yi Xue Za Zhi ; 101(4): 254-258, 2021 Jan 26.
Artigo em Chinês | MEDLINE | ID: mdl-33486933

RESUMO

Objective: To explore the value of neuroendoscopy combined with fluorescence angiography in anterior circulation aneurysm clipping. Methods: A total of 15 patients with anterior circulation aneurysm from Department of Neurosurgery, Zhongnan Hospital of Wuhan University between October 2018 and January 2019 were enrolled. Neuroendoscopy combined with indocyanine green fluorescence angiography (ICGA) was used to determine the shape of the aneurysm, the specific location of the aneurysm neck and its relationship with the aneurysm-bearing artery during anterior circulation aneurysm clipping. Meanwhile, Neuroendoscopy combined with ICGA can be employed to observe whether there was stenosis and incomplete clamping of the aneurysm-bearing artery after clipping the aneurysm, and whether there was misclamping of the perforating branches hidden under the posterior wall of the aneurysm. Results: The success rate of aneurysm clipping in 15 cases was 15/15. After aneurysm clipping, ICGA and neuroendoscopy were performed. The residual aneurysm neck was detected in 3 cases, and the position of aneurysm clip was adjusted or aneurysm clips were added. In one case, the anterior choroidal aneurysm was found to be mistakenly clipped. After adjusting the aneurysm clip, ICGA and neuroendoscopy showed that the anterior choroidal artery was normal. In another case, the A1 segment aneurysm was clipped. ICGA and neuroendoscopy found that the perforating branch blood vessels were mistakenly clipped. After the adjustment of the aneurysm clip, the blood vessels recovered their patency. There were no surgical-related deaths, disability and coma cases in the study. Conclusions: During aneurysm clipping, neuroendoscopy combined with ICGA can reduce cerebral vasospasm, decrease the misclipping rate of perforation of blood vessels, and avoid residual neck of aneurysm, stenosis or occlusion of aneurysm-bearing artery by using neuroendoscopy to observe whether misclipping of the perforating branch vessels exist and whether the aneurysm is clipped. Therefore, it can reduce postoperative complications.


Assuntos
Aneurisma Intracraniano , Neuroendoscopia , Angiografia Cerebral , Angiofluoresceinografia , Humanos , Aneurisma Intracraniano/diagnóstico por imagem , Aneurisma Intracraniano/cirurgia , Procedimentos Neurocirúrgicos , Instrumentos Cirúrgicos
9.
Phys Rev E ; 102(4-1): 042132, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33212739

RESUMO

The Kitaev model on the honeycomb lattice has been receiving substantial attention due to the discovery of quantum spin liquid state associated with this model. Consequently, its classical partners such as the Kitaev-Heisenberg (KH) model and associated phase transitions become concerned. Specifically, an intermediate Kosterlitz-Thouless (KT) phase engaged in the transition from the high-temperature (T) disordered state to the low-T sixfold degenerate state is predicted in the isotropic KH model [Phys. Rev. Lett. 109, 187201 (2012)10.1103/PhysRevLett.109.187201], but so far no sufficient experimental proof has been reported. In this work, we consider an essential extension of this KH model on the honeycomb lattice by including the Kitaev exchange anisotropy that is non-negligible in realistic materials. The associated phase transitions are thus investigated using the Monte Carlo simulations. It is found that such an anisotropy will result in a degradation of the sixfold degeneracy of the ground state in the isotropic KH model down to the fourfold or twofold degenerate ground state, and the finite-T phase transitions will also be modified remarkably. Interestingly, the intermediate KT phase can be suppressed by this Kitaev exchange anisotropy. This work thus provides a more realistic description of the physics ingredient with the KH model and presents a possible explanation on absence of the intermediate phase in real materials where the Kitaev exchange anisotropy can be more or less available.

10.
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}.

11.
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.

12.
AJNR Am J Neuroradiol ; 41(8): 1405-1413, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32675335

RESUMO

BACKGROUND AND PURPOSE: Phase imaging helps determine a lesion's susceptibility. However, various inhomogenous phase patterns could be observed in the serial phase images of a lesion and render image interpretation challenging. We evaluated the diagnostic accuracy of differentiating cerebral microbleeds and calcifications from phase patterns in axial locations. MATERIALS AND METHODS: This study retrospectively enrolled 31 consecutive patients undergoing both CT and MR imaging for acute infarction exhibiting dark spots in gradient-echo magnitude images. Six patients had additional quantitative susceptibility mapping images. To determine their susceptibility, 2 radiologists separately investigated the phase patterns in the border and central sections and quantitative susceptibility mapping of dark spots. Sensitivity and specificity were compared using the McNemar test. Interobserver reliability and correlation analysis were determined using the κ coefficient and Pearson correlation coefficient, respectively. RESULTS: Among 190 gradient-echo dark spots, 62 calcifications and 128 cerebral microbleeds were detected from CT. Interobserver reliability was higher for the border phase patterns (κ = 1) than for the central phase patterns (κ = 0.77, P < .05). The sensitivity and specificity of the border phase patterns in identifying calcifications were higher than those of the central phase patterns (98.4% and 100% versus 79% and 83.6%), particularly for lesions >2.5 mm in diameter (100% and 100% versus 66.7% and 61.1%). The same values were obtained using quantitative susceptibility mapping for identification (100% and 100%). A high correlation between the size and susceptibility of cerebral microbleeds and calcifications suggested that greater phase changes may be caused by larger lesions. CONCLUSIONS: The border phase patterns were more accurate than the central phase patterns in differentiating calcifications and cerebral microbleeds and was as accurate as quantitative susceptibility mapping.


Assuntos
Calcinose/diagnóstico por imagem , Hemorragia Cerebral/diagnóstico por imagem , Interpretação de Imagem Assistida por Computador/métodos , Neuroimagem/métodos , Idoso , Idoso de 80 Anos ou mais , Hemorragia Cerebral/patologia , Feminino , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Sensibilidade e Especificidade , Tomografia Computadorizada por Raios X
13.
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.

14.
Phys Rev Lett ; 124(24): 242001, 2020 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-32639837

RESUMO

The processes X(3872)→D^{*0}D[over ¯]^{0}+c.c.,γJ/ψ,γψ(2S), and γD^{+}D^{-} are searched for in a 9.0 fb^{-1} data sample collected at center-of-mass energies between 4.178 and 4.278 GeV with the BESIII detector. We observe X(3872)→D^{*0}D^{0}[over ¯]+c.c. and find evidence for X(3872)→γJ/ψ with statistical significances of 7.4σ and 3.5σ, respectively. No evident signals for X(3872)→γψ(2S) and γD^{+}D^{-} are found, and the upper limit on the relative branching ratio R_{γψ}≡{B[X(3872)→γψ(2S)]}/{B[X(3872)→γJ/ψ]}<0.59 is set at 90% confidence level. Measurements of branching ratios relative to decay X(3872)→π^{+}π^{-}J/ψ are also reported for decays X(3872)→D^{*0}D^{0}[over ¯]+c.c.,γψ(2S),γJ/ψ, and γD^{+}D^{-}, as well as the non-D^{*0}D^{0}[over ¯] three-body decays π^{0}D^{0}D^{0}[over ¯] and γD^{0}D^{0}[over ¯].

15.
Phys Rev Lett ; 124(24): 241803, 2020 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-32639841

RESUMO

Using 2.93 fb^{-1} of e^{+}e^{-} collision data taken at a center-of-mass energy of 3.773 GeV with the BESIII detector, we report the first measurements of the absolute branching fractions of 14 hadronic D^{0(+)} decays to exclusive final states with an η, e.g., D^{0}→K^{-}π^{+}η, K_{S}^{0}π^{0}η, K^{+}K^{-}η, K_{S}^{0}K_{S}^{0}η, K^{-}π^{+}π^{0}η, K_{S}^{0}π^{+}π^{-}η, K_{S}^{0}π^{0}π^{0}η, and π^{+}π^{-}π^{0}η; D^{+}→K_{S}^{0}π^{+}η, K_{S}^{0}K^{+}η, K^{-}π^{+}π^{+}η, K_{S}^{0}π^{+}π^{0}η, π^{+}π^{+}π^{-}η, and π^{+}π^{0}π^{0}η. Among these decays, the D^{0}→K^{-}π^{+}η and D^{+}→K_{S}^{0}π^{+}η decays have the largest branching fractions, which are B(D^{0}→K^{-}π^{+}η)=(1.853±0.025_{stat}±0.031_{syst})% and B(D^{+}→K_{S}^{0}π^{+}η)=(1.309±0.037_{stat}±0.031_{syst})%, respectively. The charge-parity asymmetries for the six decays with highest event yields are determined, and no statistically significant charge-parity violation is found.

16.
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}.

17.
Zhonghua Yi Xue Za Zhi ; 100(23): 1773-1777, 2020 Jun 16.
Artigo em Chinês | MEDLINE | ID: mdl-32536121

RESUMO

Objective: To investigate the associated factors of different dimensions of fatigue in elderly patients with rheumatoid arthritis (RA). Methods: A cross-sectional analysis was performed in the elderly outpatients with RA (age ≥ 60 years) in the First Affiliated Hospital of Sun Yat-sen University from January 2018 to June 2019. Fatigue was measured by Multidimensional Fatigue Inventory-20 (MFI-20) and 36-item Short Form Health Survey-Vitality (SF-36-VT). Physical fatigue and mental fatigue were subsequently measured by MFI-20 subscales. Results: A total of 104 patients were included. Male-to-female ratio was 1∶3.3. The average age was (68±6) years. The MFI-20 score and SF-36-VT score were 60±14 and 64±20, respectively. The score of physical fatigue measured by MFI-20 was 14±3, and mental fatigue scored 10±4 (P<0.001). Arthralgia, disease activity, disability, insomnia, depression and anxiety were correlated with fatigue assessed by MFI-20 (correlated coefficient: 0.48-0.62). Multivariable regression analysis showed that arthralgia and depression were associated with physical fatigue (Standardized regression coefficients were 0.44 and 0.38, respectively). Insomnia, depression and anxiety were associated factors of mental fatigue (Standardized regression coefficients were 0.20, 0.32 and 0.24, respectively). Conclusions: Elderly patients with RA experiencehigh level of fatigue, mainly presenting as physical fatigue. Arthralgia and depression mainly affect physical fatigue, and arthralgia is a critical factor. Insomnia, depression and anxiety are associated with mental fatigue.


Assuntos
Artrite Reumatoide , Transtorno Depressivo , Idoso , Ansiedade , Estudos Transversais , Depressão , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Índice de Gravidade de Doença , Inquéritos e Questionários
18.
Zhonghua Liu Xing Bing Xue Za Zhi ; 41(5): 738-742, 2020 May 10.
Artigo em Chinês | MEDLINE | ID: mdl-32447917

RESUMO

Objective: To explore the daily dietary behaviors of girls under precocious puberty and provide targeted measures for the prevention of precocious puberty. Methods: A case control study was conducted in a hospital in Shenzhen between September 2016 and December 2018. Girls with diagnosed precocious puberty were selected as case group. A 1∶1 matching was conducted. The control group was from 26 primary schools in Shenzhen. Dietary survey was conducted in parents, completing a self-administered questionnaire. Frequencies of 12 kinds of food intakes were investigated and dietary patterns were analyzed. Conditional logistic regression was used to analyze the relationship between dietary patterns and precocious puberty. Results: A total of 568 girls were included in the study. Among them, those aged 8-year-old accounted for highest proportion (43.8%). The median of age was same in both case group and control group (8 years-old). There was no significant difference in ethnic group between two groups (P>0.05). The medians of height, weight and BMI of case group were 135.0 cm, 30.2 kg and 16.6 kg/m(2), respectively, which were all higher than those of the control group (129.2 cm, 25.0 kg and 15.3 kg/m(2)), the differences were significant (P<0.05). There was significant difference in nutritional assessment result between two groups (P< 0.05). Three dietary patterns were defined, i.e. balanced pattern, high calorie and fat pattern and high protein diet pattern. The cumulative rate of variance contribution of the three dietary patterns was 0.541 2. The differences in the prevalence of three dietary patterns between two groups were significant (χ(2)=4.41, χ(2)=49.24, χ(2)=39.68, P<0.05 respectively). Data from the multivariate regression analysis showed that both balanced dietary pattern (OR=0.633, 95%CI: 0.504-0.769) and high protein diet pattern (OR=0.622, 95%CI: 0.498-0.776) were protective factors for precocious puberty, while high calorie and fat pattern was risk factors (OR=1.850, 95%CI: 1.461-2.342). Conclusions: Balanced dietary pattern was common in school-aged girls. High calorie and fat pattern was risk factor for precocious puberty. Children should be encouraged to develop a balanced dietary habit and increasing the intake of legumes and fish since they are beneficial to normal growth and development.


Assuntos
Puberdade Precoce , Estudos de Casos e Controles , Criança , Dieta , Comportamento Alimentar , Feminino , Humanos , Instituições Acadêmicas
19.
Phys Rev Lett ; 124(11): 112001, 2020 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-32242687

RESUMO

A partial-wave analysis is performed for the process e^{+}e^{-}→K^{+}K^{-}π^{0}π^{0} at the center-of-mass energies ranging from 2.000 to 2.644 GeV. The data samples of e^{+}e^{-} collisions, collected by the BESIII detector at the BEPCII collider with a total integrated luminosity of 300 pb^{-1}, are analyzed. The total Born cross sections for the process e^{+}e^{-}→K^{+}K^{-}π^{0}π^{0}, as well as the Born cross sections for the subprocesses e^{+}e^{-}→ϕπ^{0}π^{0}, K^{+}(1460)K^{-}, K_{1}^{+}(1400)K^{-}, K_{1}^{+}(1270)K^{-}, and K^{*+}(892)K^{*-}(892), are measured versus the center-of-mass energy. The corresponding results for e^{+}e^{-}→K^{+}K^{-}π^{0}π^{0} and ϕπ^{0}π^{0} are consistent with those of BABAR with better precision. By analyzing the cross sections for the four subprocesses, K^{+}(1460)K^{-}, K_{1}^{+}(1400)K^{-}, K_{1}^{+}(1270)K^{-}, and K^{*+}(892)K^{*-}(892), a structure with mass M=(2126.5±16.8±12.4) MeV/c^{2} and width Γ=(106.9±32.1±28.1) MeV is observed with an overall statistical significance of 6.3σ, although with very limited significance in the subprocesses e^{+}e^{-}→K_{1}^{+}(1270)K^{-} and K^{*+}(892)K^{*-}(892). The resonant parameters of the observed structure suggest it can be identified with the ϕ(2170), thus the results provide valuable input to the internal nature of the ϕ(2170).

20.
Zhonghua Yi Xue Za Zhi ; 100(7): 521-526, 2020 Feb 25.
Artigo em Chinês | MEDLINE | ID: mdl-32164104

RESUMO

Objective: To evaluate the safety and efficacy of the combined use of ultrasonic bone curette with the high-speed drill in posterior laminectomy and decompression procedure for severe thoracic spinal stenosis, and propose the optimal cutting position for ultrasonic bone curette during the laminectomy. Methods: By observing and measuring the parameters of thoracic pedicle, lamina, inner wall of the vertebral canal and their relation with the surrounding structures on cadavers, we provided a morphological marker for laminectomy by an ultrasonic bone curette. Data of 19 patients with severe thoracic spinal stenosis treated by posterior laminectomy and decompression were collected from June 2017 to June 2018 in Shanghai Changzheng Hospital. There were 11 males and 8 females, aged (50±6) years. The patients received laminectomy with the combined use of ultrasonic bone curette and the high-speed drill (Group A, n=10) or the use of ultrasonic bone curette alone (Group B, n=9). Operational time of decompressive laminectomy, blood loss, as well as perioperative complications such as durotomy, cerebrospinal fluid leak, injury of the nerve root and spinal cord were recorded in these two groups. The improvement of symptoms and the decompression width of the spinal canal were evaluated after operation. Two independent samples t-test was used for the comparison of two sets of continuous normal distribution data. Results: We had done the measurement in 6 cadavers. The mean distance between the boundary of cancellous-cortical bone of lamina and the inner wall of spinal canal was (0.9±0.4) mm, and the distance between the boundary of cancellous-cortical bone of pedicle and the inner wall of the spinal canal was (1.2±0.6) mm. For the surgeries in groups A, the mean laminectomy time for each segment was (4.4±0.5) min, the mean width of posterior laminectomy was (21.8±0.5) mm; and for the surgeries in group B, the mean laminectomy time for each segment was (5.0±0.5) min, the mean width of posterior laminectomy was (19.9±1.0) mm; there were significant differences in laminectomy time for each segment and the width of posterior laminectomy between the two groups (t=-2.391, 3.491, both P<0.05). There was one case of dura injury and one case of thoracic nerve root injury during the operation in group B. Conclusions: It is safer and more reliable for the combined use of ultrasonic bone curette with the high-speed drill in posterior laminectomy and decompression procedure for the severe thoracic spinal stenosis. The interface between the cortical bone and the medial edge of cancellous bone of the pedicle could be identified as the cutting mark for ultrasonic bone curette in this procedure.


Assuntos
Laminectomia , Estenose Espinal , Adulto , China , Descompressão Cirúrgica , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Resultado do Tratamento , Ultrassom
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...