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1.
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.

2.
Phys Rev Lett ; 132(13): 131002, 2024 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-38613275

RESUMO

We present the measurements of all-particle energy spectrum and mean logarithmic mass of cosmic rays in the energy range of 0.3-30 PeV using data collected from LHAASO-KM2A between September 2021 and December 2022, which is based on a nearly composition-independent energy reconstruction method, achieving unprecedented accuracy. Our analysis reveals the position of the knee at 3.67±0.05±0.15 PeV. Below the knee, the spectral index is found to be -2.7413±0.0004±0.0050, while above the knee, it is -3.128±0.005±0.027, with the sharpness of the transition measured with a statistical error of 2%. The mean logarithmic mass of cosmic rays is almost heavier than helium in the whole measured energy range. It decreases from 1.7 at 0.3 PeV to 1.3 at 3 PeV, representing a 24% decline following a power law with an index of -0.1200±0.0003±0.0341. This is equivalent to an increase in abundance of light components. Above the knee, the mean logarithmic mass exhibits a power law trend towards heavier components, which is reversal to the behavior observed in the all-particle energy spectrum. Additionally, the knee position and the change in power-law index are approximately the same. These findings suggest that the knee observed in the all-particle spectrum corresponds to the knee of the light component, rather than the medium-heavy components.

3.
Clin Radiol ; 2024 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-39013667

RESUMO

AIM: To investigate the value of the combined model based on spectral quantitative parameters, radiomics features, imaging and clinical features to distinguish the benign and malignant pure ground-glass nodules (pGGNs). MATERIALS AND METHODS: A retrospective analysis of 113 patients with single pGGNs who underwent non-contrast enhancement examination of the chest on dual-layer spectral detector CT (SDCT) with two weeks before surgery was performed in our hospital. These patients were randomized into training and testing cohorts. Regions of interest based on the conventional 120 kVp poly energetic image of SDCT were outlined. Then the optimal features were extracted and selected to construct radiomic model. A combined model combining vacuole sign, electron density (ED) value and the rad score of radiomics model was built by logistic regression analysis. A nomogram was built in a training cohort and the performance of the models was evaluated in the training and testing cohorts by receiver operating characteristic curves, calibration curves and decision curve analysis. RESULTS: ED value [Odds Ratio (OR):1.100; 95% confidence interval (CI):1.027-1.166)] and vacuole sign (OR:3.343; 95% CI:0.881-12.680) were independent risk factors for the malignant pGGNs in the training cohort. A combined model was constructed using radiomics features, ED value and vacuole sign. And the AUC was 0.910 (95% CI, 0.825-0.997) and 0.850 (95% CI, 0.714-0.981) in the training and testing cohorts, respectively. CONCLUSION: The combined model based on SDCT has high specificity and sensitivity for distinguishing the benign and malignant pGGNs, suggesting the model can further improve diagnostic performance, and using a nomogram is helpful for individualized predictions.

4.
HPB (Oxford) ; 26(7): 949-959, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38705794

RESUMO

BACKGROUND: Risk assessment models for acute kidney injury (AKI) after major hepatectomy that differentiate between early and late AKI are lacking. This retrospective study aimed to create a model predicting AKI through machine learning and identify features that contribute to the development of early and late AKI. METHODS: Patients that underwent major hepatectomy were categorized into the No-AKI, Early-AKI (within 48 h) or Late-AKI group (between 48 h and 7 days). Modeling was done with 20 perioperative features and the performance of prediction models were measured by the area under the receiver operating characteristic curve (AUROCC). Shapley Additive Explanation (SHAP) values were utilized to explain the outcome of the prediction model. RESULTS: Of the 1383 patients included in this study, 1229, 110 and 44 patients were categorized into the No-AKI, Early-AKI and Late-AKI group, respectively. The CatBoost classifier exhibited the greatest AUROCC of 0.758 (95% CI: 0.671-0.847) and was found to differentiate well between Early and Late-AKI. We identified different perioperative features for predicting each outcome and found 1-year mortality to be greater for Early-AKI. CONCLUSIONS: Our results suggest that risk factors are different for Early and Late-AKI after major hepatectomy, and 1-year mortality is greater for Early-AKI.


Assuntos
Injúria Renal Aguda , Hepatectomia , Aprendizado de Máquina , Humanos , Hepatectomia/efeitos adversos , Injúria Renal Aguda/etiologia , Injúria Renal Aguda/diagnóstico , Estudos Retrospectivos , Masculino , Feminino , Medição de Risco , Pessoa de Meia-Idade , Fatores de Risco , Fatores de Tempo , Idoso , Valor Preditivo dos Testes , Complicações Pós-Operatórias/etiologia
5.
Zhonghua Yan Ke Za Zhi ; 60(3): 215-219, 2024 Mar 11.
Artigo em Zh | MEDLINE | ID: mdl-38462368

RESUMO

Neovascular age-related macular degeneration (nAMD) is a leading cause of blindness in the elderly, and anti-vascular endothelial growth factor (VEGF) therapy is currently the primary treatment approach. However, the real-world effectiveness of nAMD treatment is not always satisfactory and faces various challenges. Frequent administration and follow-up burdens can lead to decreased patient compliance during long-term treatment, resulting in suboptimal outcomes. Some lesions exhibit poor or no response to anti-VEGF treatment, leading to difficulties in maintaining or even declining visual acuity. Factors such as lesion fibrosis and tissue atrophy can contribute to visual deterioration. Therefore, standardizing and individualizing treatment plans, along with enhancing comprehensive monitoring and management throughout the disease course, are crucial improvement measures. The evidence-based guidelines for diagnosis and treatment of age-related macular degeneration in China, released in 2023, provide guidance for standardized clinical diagnosis and treatment. Meanwhile, research and development of new drugs and administration methods are anticipated for the future.


Assuntos
Degeneração Macular , Degeneração Macular Exsudativa , Humanos , Idoso , Ranibizumab/uso terapêutico , Inibidores da Angiogênese/uso terapêutico , Fator A de Crescimento do Endotélio Vascular , Degeneração Macular/terapia , Acuidade Visual , Injeções Intravítreas , Degeneração Macular Exsudativa/tratamento farmacológico , Resultado do Tratamento
6.
Zhonghua Yan Ke Za Zhi ; 60(7): 570-579, 2024 Jul 11.
Artigo em Zh | MEDLINE | ID: mdl-38955759

RESUMO

Objective: To evaluate the efficacy and safety of the subthreshold micropulse laser (SMPL) combined with ranibizumab in treating diabetic macular edema (DME). Methods: This was a prospective randomized controlled study. Patients diagnosed with DME in the Ophthalmology Department of Beijing Hospital were enrolled from January 2020 to December 2022. Patients were randomized in a ratio of 1∶1 using a table of random numbers into the ranibizumab monotherapy group and the SMPL combined with ranibizumab therapy group. We compared the changes of best-corrected visual acuity, central macular thickness measured by optical coherence tomography and optical coherence tomography angiography parameters, including the vessel density of the superficial and deep capillary plexus (DCP), foveal avascular zone size and peripapillary vessel density, at baseline, 6 and 12 months after the treatment. After 12 months of follow-up, fundus fluorescein angiography results, adverse events, and the number of injections or laser therapies were recorded. The Fisher's exact test and group t-test were used for statistical analysis. Results: Seventy-two patients (72 eyes) were enrolled, with a mean age of (61.1±8.2) years. Patients in the combination therapy group included 19 males and 17 females, while patients in the ranibizumab monotherapy group were 17 males and 19 females. There was no statistically significant difference in baseline characteristics between the two groups (P>0.05). A significant improvement in best-corrected visual acuity was shown in both groups at 6 and 12 months [(58.5±12.9) and (58.2±12.2) ETDRS letters in the combination therapy group, and (63.3±13.1) and (63.8±12.5) ETDRS letters in the ranibizumab monotherapy group]. A significant reduction in central macular thickness was shown in both groups at 6 and 12 months [(451.0±185.5) and (380.4±159.3)µm in the combination therapy group, and (387.5±135.5) and (372.8±146.1)µm in the ranibizumab monotherapy group]. However, there was no significant difference between groups at each timepoint (all P>0.05). At 12 months, the vessel density of the superficial capillary plexus showed no statistical difference compared to the baseline value in each group or between groups (42.6%±5.9% in the ranibizumab monotherapy group and 42.2%±5.5% in the combination therapy group, P>0.05). The vessel density of the DCP in the combination therapy group significantly increased to 47.5%±5.6% at 12 months, significantly different from that in the ranibizumab group (43.4%±5.1%; P<0.05). The foveal avascular zone size in the ranibizumab monotherapy group reduced to (0.32±0.13) mm2, significantly different from that in the combination therapy group [(0.34±0.16) mm2] at 12 months (P<0.05). Patients in the ranibizumab monotherapy group received (7.3±2.5) intravitreal injections, while patients in the combination therapy group received 3 injections. No unfavorable outcomes on fundus fluorescein angiography or systemic or topical severe adverse events were observed during the follow-up. Conclusions: The SMPL combined with intravitreal ranibizumab injections was effective and safe in treating DME patients. The combination treatment significantly reduced the number of injections and improved the vessel density of the DCP and macular ischemia, compared to the ranibizumab monotherapy.


Assuntos
Retinopatia Diabética , Edema Macular , Ranibizumab , Humanos , Edema Macular/terapia , Edema Macular/tratamento farmacológico , Retinopatia Diabética/terapia , Ranibizumab/uso terapêutico , Estudos Prospectivos , Resultado do Tratamento , Injeções Intravítreas , Acuidade Visual , Inibidores da Angiogênese/uso terapêutico , Inibidores da Angiogênese/administração & dosagem , Fotocoagulação a Laser/métodos , Feminino , Masculino , Pessoa de Meia-Idade , Angiofluoresceinografia
7.
Osteoarthritis Cartilage ; 31(1): 26-38, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36241137

RESUMO

OBJECTIVE: The incidence of osteoarthritis (OA) in menopausal women is significantly higher than in same-aged men. Investigating the role of subchondral osteoblasts in estrogen deficiency-induced OA may help elucidate the pathological mechanism, providing new insights for the diagnosis and treatment of menopausal OA. METHODS: A classical ovariectomy-induced OA (OVX-OA) rat model was utilized to isolate primary articular chondrocytes and subchondral osteoblasts, which were identified and then cocultured in Transwell. The expression of chondrocyte anabolic and catabolic indicators was evaluated. The differentially expressed proteins in the conditioned medium (CM) of osteoblasts were identified by Liquid Chromatograph-Mass Spectrometer (LC-MS/MS). Normal chondrocytes were treated with osteoblast CM, and then RNA sequencing was performed on the treated chondrocytes. KEGG was used to identify significant enrichment of signaling pathways, and Simple Western was used to verify the expression of related proteins in the signaling pathways. RESULTS: Coculture of OVX-OA subchondral osteoblasts with chondrocytes significantly downregulated the expression of the anabolic indicators and upregulated the expression of the catabolic indicators in chondrocytes. 1,601 proteins were identified in both normal and OVX osteoblast culture supernatants. Protein-protein interaction network analysis revealed that Sparc was one of the hub proteins. The AMPK/Foxo3a signaling pathway of chondrocytes was downregulated by OVX-OA osteoblasts CM. AICAR, the AMPK agonist, partially reversed the catabolic effect of OVX-OA osteoblasts on chondrocytes. CONCLUSIONS: Sparc secreted by OVX-OA subchondral osteoblasts can downregulate the AMPK/Foxo3a signaling pathway of chondrocytes, thereby promoting chondrocyte degeneration.


Assuntos
Cartilagem Articular , Osteoartrite , Osteonectina , Animais , Feminino , Ratos , Proteínas Quinases Ativadas por AMP/metabolismo , Cartilagem Articular/patologia , Células Cultivadas , Condrócitos/metabolismo , Cromatografia Líquida , Estrogênios/farmacologia , Osteoartrite/metabolismo , Osteoblastos , Espectrometria de Massas em Tandem , Osteonectina/metabolismo
8.
Phys Rev Lett ; 131(15): 151001, 2023 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-37897763

RESUMO

The diffuse Galactic γ-ray emission, mainly produced via interactions between cosmic rays and the interstellar medium and/or radiation field, is a very important probe of the distribution, propagation, and interaction of cosmic rays in the Milky Way. In this Letter, we report the measurements of diffuse γ rays from the Galactic plane between 10 TeV and 1 PeV energies, with the square kilometer array of the Large High Altitude Air Shower Observatory (LHAASO). Diffuse emissions from the inner (15°10 TeV). The energy spectrum in the inner Galaxy regions can be described by a power-law function with an index of -2.99±0.04, which is different from the curved spectrum as expected from hadronic interactions between locally measured cosmic rays and the line-of-sight integrated gas content. Furthermore, the measured flux is higher by a factor of ∼3 than the prediction. A similar spectrum with an index of -2.99±0.07 is found in the outer Galaxy region, and the absolute flux for 10≲E≲60 TeV is again higher than the prediction for hadronic cosmic ray interactions. The latitude distributions of the diffuse emission are consistent with the gas distribution, while the longitude distributions show clear deviation from the gas distribution. The LHAASO measurements imply that either additional emission sources exist or cosmic ray intensities have spatial variations.

9.
Phys Rev Lett ; 131(12): 121801, 2023 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-37802947

RESUMO

We report on the first search for Λ[over ¯]-Λ oscillations in the decay J/ψ→pK^{-}Λ[over ¯]+c.c. by analyzing 1.31×10^{9} J/ψ events accumulated with the BESIII detector at the BEPCII collider. The J/ψ events are produced using e^{+}e^{-} collisions at a center of mass energy sqrt[s]=3.097 GeV. No evidence for hyperon oscillations is observed. The upper limit for the oscillation rate of Λ[over ¯] to Λ hyperons is determined to be P(Λ)=[B(J/ψ→pK^{-}Λ+c.c.)/B(J/ψ→pK^{-}Λ[over ¯]+c.c.)]<4.4×10^{-6} corresponding to an oscillation parameter δm_{ΛΛ[over ¯]} of less than 3.8×10^{-18} GeV at the 90% confidence level.

10.
Zhonghua Jie He He Hu Xi Za Zhi ; 46(1): 34-39, 2023 Jan 12.
Artigo em Zh | MEDLINE | ID: mdl-36617926

RESUMO

Objective: To investigate the efficacy and safety of transbronchial cryobiopsy (TBCB) after lung transplantation. Methods: The clinical characteristics, TBCB procedure, diagnosis and treatment, and outcomes of lung transplant recipients of 6 patients (all male, aged 33-67 years) with TBCB in China-Japan Friendship Hospital from May to November 2021 were retrospectively analyzed. Results: Among the 6 patients diagnosed by TBCB, there were 2 cases of organizing pneumonia, 1 acute cellular rejection, 1 antibody-mediated rejection, and 1 bronchiolitis obliterans, and 1 diffuse alveolar damage. After the clinical diagnosis was confirmed, the condition improved after adjustment of the treatments followed. There were no serious complications related to the TBCB procedure. Conclusion: TBCB is valuable and relatively safe in the diagnosis of complications after lung transplantation, but the indications need to be strictly controlled.


Assuntos
Doenças Pulmonares Intersticiais , Transplante de Pulmão , Humanos , Masculino , Biópsia/métodos , Broncoscopia/efeitos adversos , Broncoscopia/métodos , Pulmão/patologia , Doenças Pulmonares Intersticiais/etiologia , Doenças Pulmonares Intersticiais/complicações , Transplante de Pulmão/efeitos adversos , Complicações Pós-Operatórias/diagnóstico , Estudos Retrospectivos , Adulto , Pessoa de Meia-Idade , Idoso
11.
Zhonghua Xin Xue Guan Bing Za Zhi ; 51(11): 1188-1193, 2023 Nov 24.
Artigo em Zh | MEDLINE | ID: mdl-37963755

RESUMO

Objective: To analyze the classification, diagnosis and treatment status of patients with pulmonary hypertension (PH) in Yunnan province. Methods: This was a retrospective study. Hospitalized patients with PH at Yan'an Affiliated Hospital of Kunming Medical University from January 2012 to December 2019 were enrolled. The clinical data of enrolled patients, including demographic data, comorbidities, targeted drug therapy, echocardiography and right heart catheterization results, were obtained through the electronic medical record system. The composition ratio of PH, diagnosis and treatment were analyzed. Results: A total of 13 590 patients with PH were enrolled, accounting for 3.09% (13 590/440 056) of the total number of hospitalizations during the same period. The composition of PH was predominantly pulmonary arterial hypertension (PAH) (55.50% (7 542/13 590)), followed by pulmonary hypertension (PH) caused by left heart disease (24.16% (3 284/13 590)). Among them, PAH could be subdivided into four types: idiopathic pulmonary arterial hypertension (IPAH), PAH associated with connective tissue disease, PAH associated with portal hypertension, and PAH associated with congenital heart disease (CHD-PAH), with CHD-PAH as the predominating type (98.09% (7 398/7 542). Patients with PAH were predominantly adolescents. In hospitalized patients with PH, from 2012 to 2019, the proportion of children and adolescents showed a decreasing trend from year to year, and the proportion of middle-aged and older adults showed a significant increasing trend, and the proportion of female patients showed a gradual decreasing trend, and the proportion of patients with comorbid hypertension, diabetes mellitus, coronary artery disease, arrhythmia, and pneumonia showed an increasing trend. A total of 1 034 patients (7.61% (1 034/13 590)) underwent right heart catheterization. The concordance rate between echocardiographic and right heart catheterization findings was (86.98% (875/1 006)). A total of 2 574 (18.94%) of PH patients were treated with PAH targeted drugs, of which 58.16% (1 497/2 574) were treated with monotherapy. Among the PH patients treated with PAH targeted drugs, the majority of patients were PAH patients (86.44% (2 225/2 574)), and 83.53% (2 150/2 574) patients treated with PAH targeted drugs were CHD-PAH. Conclusions: Hospitalized PH patients in our center between 2012 and 2019 are predominantly CHD-PAH, and the proportion of patients receiving right heart catheterization and targeted drug therapy is relatively low. The percentage of middle-aged and elderly PH patients shows an increasing trend from year to year, as well as the percentage of those with concomitant comorbidities.


Assuntos
Cardiopatias Congênitas , Hipertensão Pulmonar , Hipertensão Arterial Pulmonar , Criança , Idoso , Adolescente , Pessoa de Meia-Idade , Humanos , Feminino , Hipertensão Pulmonar/diagnóstico , Hipertensão Pulmonar/terapia , Estudos Retrospectivos , China/epidemiologia , Hipertensão Pulmonar Primária Familiar , Hipertensão Arterial Pulmonar/complicações
12.
Phys Rev Lett ; 128(14): 142001, 2022 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-35476477

RESUMO

The singly Cabibbo-suppressed decay Λ_{c}^{+}→nπ^{+} is observed for the first time with a statistical significance of 7.3σ by using 3.9 fb^{-1} of e^{+}e^{-} collision data collected at center-of-mass energies between 4.612 and 4.699 GeV with the BESIII detector at BEPCII. The branching fraction of Λ_{c}^{+}→nπ^{+} is measured to be (6.6±1.2_{stat}±0.4_{syst})×10^{-4}. By taking the upper limit of branching fractions of Λ_{c}^{+}→pπ^{0} from the Belle experiment, the ratio of branching fractions between Λ_{c}^{+}→nπ^{+} and Λ_{c}^{+}→pπ^{0} is calculated to be larger than 7.2 at the 90% confidence level, which disagrees with most predictions of the available phenomenological models. In addition, the branching fractions of the Cabibbo-favored decays Λ_{c}^{+}→Λπ^{+} and Λ_{c}^{+}→Σ^{0}π^{+} are measured to be (1.31±0.08_{stat}±0.05_{syst})×10^{-2} and (1.22±0.08_{stat}±0.07_{syst})×10^{-2}, respectively, which are consistent with previous results.

13.
Phys Rev Lett ; 129(2): 022002, 2022 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-35867444

RESUMO

Using a sample of about 10^{10} J/ψ events collected at a center-of-mass energy sqrt[s]=3.097 GeV with the BESIII detector, the electromagnetic Dalitz decays J/ψ→e^{+}e^{-}π^{+}π^{-}η^{'}, with η^{'}→γπ^{+}π^{-} and η^{'}→π^{+}π^{-}η, have been studied. The decay J/ψ→e^{+}e^{-}X(1835) is observed with a significance of 15σ, and also an e^{+}e^{-} invariant-mass dependent transition form factor of J/ψ→e^{+}e^{-}X(1835) is presented for the first time. The intermediate states X(2120) and X(2370) are also observed in the π^{+}π^{-}η^{'} invariant-mass spectrum with significances of 5.3σ and 7.3σ. The corresponding product branching fractions for J/ψ→e^{+}e^{-}X, X→π^{+}π^{-}η^{'} [X=X(1835), X(2120), and X(2370)] are reported.

14.
Phys Rev Lett ; 128(6): 062004, 2022 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-35213186

RESUMO

Based on electron-positron collision data collected with the BESIII detector operating at the Beijing Electron-Positron Collider II storage rings, the value of R≡σ(e^{+}e^{-}→hadrons)/σ(e^{+}e^{-}→µ^{+}µ^{-}) is measured at 14 center-of-mass energies from 2.2324 to 3.6710 GeV. The resulting uncertainties are less than 3.0% and are dominated by systematic uncertainties.

15.
Phys Rev Lett ; 128(1): 011803, 2022 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-35061485

RESUMO

Using a data sample corresponding to an integrated luminosity of 2.93 fb^{-1} collected at a center-of-mass energy sqrt[s]=3.773 GeV by the BESIII detector, the decay D^{0}→ωϕ is observed for the first time. The branching fraction is measured to be (6.48±0.96±0.40)×10^{-4} with a significance of 6.3σ, where the first and second uncertainties are statistical and systematic, respectively. An angular analysis reveals that the ϕ and ω mesons from the D^{0}→ωϕ decay are transversely polarized. The 95% confidence level upper limit on longitudinal polarization fraction is set to be less than 0.24, which is inconsistent with current theoretical expectations and challenges our understanding of the underlying dynamics in charm meson decays.

16.
Phys Rev Lett ; 128(5): 051102, 2022 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-35179919

RESUMO

Recently, the LHAASO Collaboration published the detection of 12 ultrahigh-energy γ-ray sources above 100 TeV, with the highest energy photon reaching 1.4 PeV. The first detection of PeV γ rays from astrophysical sources may provide a very sensitive probe of the effect of the Lorentz invariance violation (LIV), which results in decay of high-energy γ rays in the superluminal scenario and hence a sharp cutoff of the energy spectrum. Two highest energy sources are studied in this work. No signature of the existence of the LIV is found in their energy spectra, and the lower limits on the LIV energy scale are derived. Our results show that the first-order LIV energy scale should be higher than about 10^{5} times the Planck scale M_{Pl} and that the second-order LIV scale is >10^{-3}M_{Pl}. Both limits improve by at least one order of magnitude the previous results.

17.
Phys Rev Lett ; 129(18): 182001, 2022 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-36374689

RESUMO

Using e^{+}e^{-} annihilation data corresponding to an integrated luminosity of 6.32 fb^{-1} collected at center-of-mass energies between 4.178 and 4.226 GeV with the BESIII detector, we perform the first amplitude analysis of the decay D_{s}^{+}→K_{S}^{0}K^{+}π^{0} and determine the relative branching fractions and phases for intermediate processes. We observe an a_{0}-like state with mass of 1.817 GeV in its decay to K_{S}^{0}K^{+} for the first time. In addition, we measure the ratio {B[D_{s}^{+}→K[over ¯]^{*}(892)^{0}K^{+}]/B[D_{s}^{+}→K[over ¯]^{0}K^{*}(892)^{+}]} to be 2.35_{-0.23stat}^{+0.42}±0.10_{syst}. Finally, we provide a precision measurement of the absolute branching fraction B(D_{s}^{+}→K_{S}^{0}K^{+}π^{0})=(1.46±0.06_{stat}±0.05_{syst})%.

18.
Phys Rev Lett ; 129(10): 102003, 2022 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-36112441

RESUMO

Using a data sample corresponding to an integrated luminosity of 11.3 fb^{-1} collected at center-of-mass energies from 4.23 to 4.70 GeV with the BESIII detector, we measure the product of the e^{+}e^{-}→π^{+}π^{-}ψ_{2}(3823) cross section and the branching fraction B[ψ_{2}(3823)→γχ_{c1}]. For the first time, resonance structure is observed in the cross section line shape of e^{+}e^{-}→π^{+}π^{-}ψ_{2}(3823) with significances exceeding 5σ. A fit to data with two coherent Breit-Wigner resonances modeling the sqrt[s]-dependent cross section yields M(R_{1})=4406.9±17.2±4.5 MeV/c^{2}, Γ(R_{1})=128.1±37.2±2.3 MeV, and M(R_{2})=4647.9±8.6±0.8 MeV/c^{2}, Γ(R_{2})=33.1±18.6±4.1 MeV. Though weakly disfavored by the data, a single resonance with M(R)=4417.5±26.2±3.5 MeV/c^{2}, Γ(R)=245±48±13 MeV is also possible to interpret data. This observation deepens our understanding of the nature of the vector charmoniumlike states. The mass of the ψ_{2}(3823) state is measured as (3823.12±0.43±0.13) MeV/c^{2}, which is the most precise measurement to date.

19.
Phys Rev Lett ; 129(26): 261103, 2022 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-36608208

RESUMO

The kilometer square array (KM2A) of the large high altitude air shower observatory (LHAASO) aims at surveying the northern γ-ray sky at energies above 10 TeV with unprecedented sensitivity. γ-ray observations have long been one of the most powerful tools for dark matter searches, as, e.g., high-energy γ rays could be produced by the decays of heavy dark matter particles. In this Letter, we present the first dark matter analysis with LHAASO-KM2A, using the first 340 days of data from 1/2-KM2A and 230 days of data from 3/4-KM2A. Several regions of interest are used to search for a signal and account for the residual cosmic-ray background after γ/hadron separation. We find no excess of dark matter signals, and thus place some of the strongest γ-ray constraints on the lifetime of heavy dark matter particles with mass between 10^{5} and 10^{9} GeV. Our results with LHAASO are robust, and have important implications for dark matter interpretations of the diffuse astrophysical high-energy neutrino emission.

20.
Nucleic Acids Res ; 48(6): 2924-2941, 2020 04 06.
Artigo em Inglês | MEDLINE | ID: mdl-31996893

RESUMO

WDR5 is a highly-conserved nuclear protein that performs multiple scaffolding functions in the context of chromatin. WDR5 is also a promising target for pharmacological inhibition in cancer, with small molecule inhibitors of an arginine-binding pocket of WDR5 (the 'WIN' site) showing efficacy against a range of cancer cell lines in vitro. Efforts to understand WDR5, or establish the mechanism of action of WIN site inhibitors, however, are stymied by its many functions in the nucleus, and a lack of knowledge of the conserved gene networks-if any-that are under its control. Here, we have performed comparative genomic analyses to identify the conserved sites of WDR5 binding to chromatin, and the conserved genes regulated by WDR5, across a diverse panel of cancer cell lines. We show that a specific cohort of protein synthesis genes (PSGs) are invariantly bound by WDR5, demonstrate that the WIN site anchors WDR5 to chromatin at these sites, and establish that PSGs are bona fide, acute, and persistent targets of WIN site blockade. Together, these data reveal that WDR5 plays a predominant transcriptional role in biomass accumulation and provide further evidence that WIN site inhibitors act to repress gene networks linked to protein synthesis homeostasis.


Assuntos
Regulação da Expressão Gênica , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Biossíntese de Proteínas/genética , Sequência de Bases , Sítios de Ligação/genética , Linhagem Celular , Cromatina/metabolismo , Sequência Conservada/genética , Feminino , Humanos , Masculino , Ligação Proteica , Transcrição Gênica , Proteína Supressora de Tumor p53/metabolismo
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