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1.
Nature ; 615(7954): 813-816, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36991189

RESUMO

The proton is one of the main building blocks of all visible matter in the Universe1. Among its intrinsic properties are its electric charge, mass and spin2. These properties emerge from the complex dynamics of its fundamental constituents-quarks and gluons-described by the theory of quantum chromodynamics3-5. The electric charge and spin of protons, which are shared among the quarks, have been investigated previously using electron scattering2. An example is the highly precise measurement of the electric charge radius of the proton6. By contrast, little is known about the inner mass density of the proton, which is dominated by the energy carried by gluons. Gluons are hard to access using electron scattering because they do not carry an electromagnetic charge. Here we investigated the gravitational density of gluons using a small colour dipole, through the threshold photoproduction of the J/ψ particle. We determined the gluonic gravitational form factors of the proton7,8 from our measurement. We used a variety of models9-11 and determined, in all cases, a mass radius that is notably smaller than the electric charge radius. In some, but not all cases, depending on the model, the determined radius agrees well with first-principle predictions from lattice quantum chromodynamics12. This work paves the way for a deeper understanding of the salient role of gluons in providing gravitational mass to visible matter.

2.
Nature ; 611(7935): 265-270, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36261531

RESUMO

The visible world is founded on the proton, the only composite building block of matter that is stable in nature. Consequently, understanding the formation of matter relies on explaining the dynamics and the properties of the proton's bound state. A fundamental property of the proton involves the response of the system to an external electromagnetic field. It is characterized by the electromagnetic polarizabilities1 that describe how easily the charge and magnetization distributions inside the system are distorted by the electromagnetic field. Moreover, the generalized polarizabilities2 map out the resulting deformation of the densities in a proton subject to an electromagnetic field. They disclose essential information about the underlying system dynamics and provide a key for decoding the proton structure in terms of the theory of the strong interaction that binds its elementary quark and gluon constituents. Of particular interest is a puzzle in the electric generalized polarizability of the proton that remains unresolved for two decades2. Here we report measurements of the proton's electromagnetic generalized polarizabilities at low four-momentum transfer squared. We show evidence of an anomaly to the behaviour of the proton's electric generalized polarizability that contradicts the predictions of nuclear theory and derive its signature in the spatial distribution of the induced polarization in the proton. The reported measurements suggest the presence of a new, not-yet-understood dynamical mechanism in the proton and present notable challenges to the nuclear theory.

3.
Nature ; 585(7824): 293-297, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32494016

RESUMO

Molecular glue compounds induce protein-protein interactions that, in the context of a ubiquitin ligase, lead to protein degradation1. Unlike traditional enzyme inhibitors, these molecular glue degraders act substoichiometrically to catalyse the rapid depletion of previously inaccessible targets2. They are clinically effective and highly sought-after, but have thus far only been discovered serendipitously. Here, through systematically mining databases for correlations between the cytotoxicity of 4,518 clinical and preclinical small molecules and the expression levels of E3 ligase components across hundreds of human cancer cell lines3-5, we identify CR8-a cyclin-dependent kinase (CDK) inhibitor6-as a compound that acts as a molecular glue degrader. The CDK-bound form of CR8 has a solvent-exposed pyridyl moiety that induces the formation of a complex between CDK12-cyclin K and the CUL4 adaptor protein DDB1, bypassing the requirement for a substrate receptor and presenting cyclin K for ubiquitination and degradation. Our studies demonstrate that chemical alteration of surface-exposed moieties can confer gain-of-function glue properties to an inhibitor, and we propose this as a broader strategy through which target-binding molecules could be converted into molecular glues.


Assuntos
Ciclinas/deficiência , Ciclinas/metabolismo , Proteólise/efeitos dos fármacos , Purinas/química , Purinas/farmacologia , Piridinas/química , Piridinas/farmacologia , Linhagem Celular Tumoral , Quinases Ciclina-Dependentes/antagonistas & inibidores , Quinases Ciclina-Dependentes/química , Quinases Ciclina-Dependentes/metabolismo , Ciclinas/química , Proteínas de Ligação a DNA/metabolismo , Humanos , Modelos Moleculares , Complexo de Endopeptidases do Proteassoma/metabolismo , Ligação Proteica/efeitos dos fármacos , Purinas/toxicidade , Piridinas/toxicidade , Bibliotecas de Moléculas Pequenas/análise , Bibliotecas de Moléculas Pequenas/química , Bibliotecas de Moléculas Pequenas/farmacologia , Ubiquitinação/efeitos dos fármacos
4.
Phys Rev Lett ; 132(17): 171001, 2024 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-38728703

RESUMO

Recently a dark matter-electron (DM-electron) paradigm has drawn much attention. Models beyond the standard halo model describing DM accelerated by high energy celestial bodies are under intense examination as well. In this Letter, a velocity components analysis (VCA) method dedicated to swift analysis of accelerated DM-electron interactions via semiconductor detectors is proposed and the first HPGe detector-based accelerated DM-electron analysis is realized. Utilizing the method, the first germanium based constraint on sub-GeV solar reflected DM-electron interaction is presented with the 205.4 kg·day dataset from the CDEX-10 experiment. In the heavy mediator scenario, our result excels in the mass range of 5-15 keV/c^{2}, achieving a 3 orders of magnitude improvement comparing with previous semiconductor experiments. In the light mediator scenario, the strongest laboratory constraint for DM lighter than 0.1 MeV/c^{2} is presented. The result proves the feasibility and demonstrates the vast potential of the VCA technique in future accelerated DM-electron analyses with semiconductor detectors.

5.
Artigo em Inglês | MEDLINE | ID: mdl-38207160

RESUMO

OBJECTIVE: Laparotomy-assisted fetoscopic closure of spina bifida utilizing heated-humidified carbon dioxide gas has been associated with less maternal morbidity than open in-utero spina bifida closure. Fetal cardiovascular changes during these surgical interventions are not well defined. Our objective was to compare fetal bradycardia (defined as fetal heart rate (FHR)<110 bpm over 10 minutes) and changes in umbilical artery Doppler parameters throughout open in-utero closure with those observed during laparotomy-assisted fetoscopic closure. METHODS: We conducted a prospective cohort study of 22 open and 46 fetoscopic consecutive in-utero closures between 2019 and 2023. Both cohorts had similar preoperative counseling and clinical management. FHR and umbilical artery velocimetry were systematically obtained during preoperative assessment, every 5 minutes during the intraoperative period, and in the postoperative assessment. FHR, pulsatility indexes and end-diastolic flows were segmented into hourly periods during surgery, and the lowest values were averaged for analysis. Umbilical vein maximum velocities were measured in the fetoscopic cohort. Each fetal heart rate recording time point was correlated to maternal parameters, including heart rate, systolic and diastolic blood pressures. RESULTS: Fetal bradycardia occurred in 4/22 cases (18.2%) of open in-utero closure and in 21/46 cases (45.7%) of fetoscopic closure. FHR gradually decreased in both cohorts after general anesthesia and decreased further during surgery. FHR were significantly lower after two hours of surgery in the fetoscopic closure than in the open in-utero closure group. In addition, the FHR (BPM) change in the final stages of the fetal surgery from the baseline FHR was significantly lower in the fetoscopic cohort (-32.3 (-35.7, -29.1)) compared to the open cohort (-23.5 (-28.1, -18.8)) (p=0.002). Abnormal end-diastolic flow (defined as absent or reversed end-diastolic flow) in the umbilical artery Doppler velocity occurred in 3/22 (13.6%) of the open closure cohort and in 23/46 (50%) of the fetoscopic closure cohort (p=0.004). There were no differences in umbilical artery end-diastolic flow and pulsatility index between closure techniques during the various stages of assessment. CONCLUSIONS: We observed a decrease in the FHR and abnormalities in umbilical artery Doppler parameters in both open in-utero and fetoscopic closure groups. Fetal bradycardia was more prominent during fetoscopic closure following heated-humidified carbon dioxide insufflation, but the FHR recovered after cessation of the heated-humidified carbon dioxide. Changes in FHR and umbilical artery Doppler parameters during in-utero spina bifida closure were observed to be transient, no cases required emergency delivery and no fetoscopic closure were converted to open closure. These observations should inform algorithms for perioperative management of fetal bradycardia associated with in-utero spina bifida closure. This article is protected by copyright. All rights reserved.

6.
Phys Chem Chem Phys ; 26(26): 17991-17998, 2024 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-38764355

RESUMO

The photo-induced dynamics of o-nitrophenol, particularly its photolysis, has garnered significant scientific interest as a potential source of nitrous acid in the atmosphere. Although the photolysis products and preceding photo-induced electronic structure dynamics have been investigated extensively, the nuclear dynamics accompanying the non-radiative relaxation of o-nitrophenol on the ultrafast timescale, which include an intramolecular proton transfer step, have not been experimentally resolved. Herein, we present a direct observation of the ultrafast nuclear motions mediating photo-relaxation using ultrafast electron diffraction. This work spatiotemporally resolves the loss of planarity which enables access to a conical intersection between the first excited state and the ground state after the proton transfer step, on the femtosecond timescale and with sub-Angstrom resolution. Our observations, supported by ab initio multiple spawning simulations, provide new insights into the proton transfer mediated relaxation mechanism in o-nitrophenol.

7.
Appl Opt ; 63(4): 976-981, 2024 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-38437394

RESUMO

The synthetic aperture infrared radio imaging method based on laser local oscillator coherent detection has potential application value for astronomical observations. This paper studies the multi-channel synthetic aperture infrared imaging method and conducts experimental verification using a principle prototype. In the short-wave infrared band, five beam-expanding fiber collimators are used to build an observation structure of five laser local oscillator coherent detection channels at a near-field distance of 5 m to carry out physical experiments. The laser local oscillator wavelength is 1.55 µm, and the AD sampling rate is 4 GHz. For the infrared radiation source signal, the phase relationship of the infrared signals between channels acquired by the prototype principle is stable, and the five-channel synthetic aperture imaging results are consistent with the computer simulated results. The experiment verified the effectiveness of the laser local oscillator comprehensive aperture infrared radio imaging method.

8.
Public Health ; 230: 172-182, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38560955

RESUMO

OBJECTIVES: The purpose of our study was to assess the multiscalar changes in leprosy burden and its associated risk factors over the last three decades. STUDY DESIGN: We conducted an in-depth examination of leprosy's spatial-temporal trends at multiple geographical scale (global, regional, and national), utilizing information from Global Burden of Disease, Injuries, and Risk Factors Study (GBD 2019). METHODS: Incidence and the estimated annual percentage change (EAPC) in age-standardized incidence rate (ASIR) of leprosy were determined, with countries categorized based on leprosy incidence changes. We examined socioeconomic and physical geography influences on leprosy incidence via Spearman correlation analysis, using ternary phase diagrams to reveal the synergetic effects on leprosy occurrence. RESULTS: Globally, incident cases of leprosy decreased by 27.86% from 1990 to 2019, with a reduction in ASIR (EAPC = -2.53), yet trends were not homogeneous across regions. ASIR and EAPC correlated positively with sociodemographic index (SDI), and an ASIR growth appeared in high SDI region (EAPC = 3.07). Leprosy burden was chiefly distributed in Tropical Latin America, Oceania, Central Sub-Saharan Africa, and South Asia. Negative correlations were detected between the incidence of leprosy and factors of SDI, GDP per capita, urban population to total population, and precipitation, whereas the number of refugee population, temperature, and elevation showed opposite positive results. CONCLUSIONS: Despite a global decline in leprosy over the past three decades, the disparities of disease occurrence at regional and national scales still persisted. Socioeconomic and physical geographic factors posed an obvious influence on the transmission risk of leprosy. The persistence and regional fluctuations of leprosy incidence necessitate the ongoing dynamic and multilayered control strategies worldwide in combating this ancient disease.


Assuntos
Carga Global da Doença , Hanseníase , Humanos , Geografia , Hanseníase/epidemiologia , Exame Físico , Fatores Socioeconômicos , Saúde Global , Incidência , Anos de Vida Ajustados por Qualidade de Vida
9.
Public Health ; 227: 202-209, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38241901

RESUMO

OBJECTIVES: This study aims to reveal the single and mixed associations of PM2.5 and its components with very, moderately, and late preterm births and to explore the potential mediating role of pregnancy complications in PM2.5-induced preterm birth. STUDY DESIGN: This was a retrospective cohort study. METHODS: We enrolled 168,852 mothers and matched the concentrations of PM2.5 and its five components (OM, SO42-, BC, NO3-, and NH4+) based on their geographical location. Next, we used generalized linear models, quantile g-computation, and mediation analysis to evaluate the associations of PM2.5 and its components with very, moderately, and late preterm births and the mediating role of pregnancy complications. RESULTS: Prenatal exposure to PM2.5 and its components was associated with preterm birth, and the association was strongest in the third trimester. Preterm birth was associated with co-exposure to a mixture of PM2.5 components in the third trimester, and the contributions of NO3-, NH4+, and BC to the risk of preterm birth were positive. Meanwhile, pregnancy complications mediated PM2.5-induced preterm birth. Moreover, very and moderately preterm births were associated with PM2.5 and its components in the second and third trimesters, and very and late preterm births were associated with co-exposure to a mixture of PM2.5 components in the third trimester. CONCLUSIONS: Later exposure to PM2.5 during pregnancy will cause earlier preterm birth. Targeted and positive interventions for anthropogenic sources of specific PM2.5 components and pregnancy complications are helpful for preterm birth prevention.


Assuntos
Poluentes Atmosféricos , Poluição do Ar , Complicações na Gravidez , Nascimento Prematuro , Efeitos Tardios da Exposição Pré-Natal , Gravidez , Feminino , Recém-Nascido , Humanos , Nascimento Prematuro/epidemiologia , Estudos de Coortes , Material Particulado/efeitos adversos , Material Particulado/análise , Estudos Retrospectivos , Exposição Materna/efeitos adversos , Poluentes Atmosféricos/efeitos adversos , Poluentes Atmosféricos/análise , Poluição do Ar/efeitos adversos , Poluição do Ar/análise , China
10.
Br Poult Sci ; 65(1): 34-43, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37807894

RESUMO

1. Intramuscular fat (IMF) is a key parameter for chicken meat quality. IMF deposition is driven by genetic, nutritional and management factors, with genetics being the determining factor. Previous whole transcriptome sequencing revealed that microRNA gga-let-7a-3p was related to lipid metabolism in breast muscle. This study further investigated the potential role of gga-let-7a-3p in IMF deposition.2. The mimic and inhibitor of gga-let-7a-3p were individually transfected into chicken intramuscular preadipocytes. Subsequently, the proliferation and differentiation states of the cells were detected. Transcriptome sequencing was performed on cells transfected with gga-let-7a-3p mimic.3. The results indicated that gga-let-7a-3p suppressed the mRNA levels of proliferation and differentiation-related genes, as well as the protein levels. EdU and Oil Red O assays revealed that gga-let-7a-3p restrained preadipocyte proliferation and differentiation. In addition, a total of 333 up-regulated genes and 807 down-regulated genes were identified in cells transfected with gga-let-7a-3p mimic. Using Kyoto Encyclopaedia of Genes and Genomes (KEGG) and Gene Ontology (GO) analysis, differential genes were found to be enriched in processes such as the peroxisome proliferator activated receptor (PPAR) signalling pathway and oxidative phosphorylation.4. The study demonstrated that gga-let-7a-3p inhibits the proliferation and differentiation of chicken intramuscular preadipocytes, which provides new understanding to further unravel the function of gga-let-7a-3p.


Assuntos
Galinhas , MicroRNAs , Animais , Galinhas/genética , Diferenciação Celular , Metabolismo dos Lipídeos , MicroRNAs/genética , Proliferação de Células
11.
Br Poult Sci ; 65(3): 273-286, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38727584

RESUMO

1. The Wulong goose is a Chinese breed and a source of high-quality meat and eggs. A characteristic of the Wulong goose is that a proportion of the birds do not have eyelids, known as the Huoyon trait.2. Wulong geese exhibiting the Huoyan trait at embryonic stages of 9 days (E9), 12 days (E12) and 14 days (E14) were selected alongside those with normal eyelids for comprehensive transcriptome sequencing. Differentially expressed gene (DEG) and functional enrichment analyses were performed and finally, eight DEG were chosen to verify the accuracy of qPCR sequencing.3. Overall, 466, 962 and 550 DEG were obtained from the three control groups, D9 vs. N9, D12 vs. N12 and D14 vs. N14, respectively, by differential analysis (p < 0.05). CDKN1C, CRH, CROCC and TYSND1 were significantly expressed in the three groups. Enrichment analysis revealed the enrichment of CROCC and TYSND1 in pathways of cell cycle process, endocytosis, microtubule-based process, microtubule organising centre organisation, protein processing and protein maturation. CDKN1C and CRH were enriched in the cell cycle and cAMP signalling pathway.4. Some collagen family genes were detected among the DEGs, including COL3A1, COL4A5, COL4A2 and COL4A1. FREM1 and FREM2 genes were detected in both Huoyan and normal eyelids. There was a significant difference (p < 0.01) in FREM1 expression between ED9 and ED14 in female embryos, but this difference was not observed in male embryos.


Assuntos
Gansos , Perfilação da Expressão Gênica , Animais , Gansos/genética , Gansos/embriologia , Perfilação da Expressão Gênica/veterinária , Transcriptoma , Proteínas Aviárias/genética , Proteínas Aviárias/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Desenvolvimento Embrionário/genética
12.
Zhonghua Yi Xue Za Zhi ; 104(21): 1907-1910, 2024 Jun 04.
Artigo em Zh | MEDLINE | ID: mdl-38825936

RESUMO

Aneurysmal subarachnoid hemorrhage (aSAH) is a life-threatening neurological emergency with high mortality, and even patients receiving optimal medical care may develop long-term disability, which seriously affects their quality of life and increases the heavy medical burden on society and families. To provide comprehensive clinical management advice, the Society of Neurosurgery of the Chinese Medical Association, the Society of the Chinese Stroke Association of the National Medical Center for Neurological Diseases, and the National Clinical Research Center for Neurological Diseases jointly formulate "Chinese Guidelines for the Clinical Management of Patients With Ruptured Intracranial Aneurysms in 2024". The evidence sources are divided into the Chinese population and other populations, using a modular format to provide recommendations, summaries of relevant opinions, and future research directions on epidemiology, clinical imaging diagnosis, prognosis evaluation, treatment strategies and choices, anesthesia management, perioperative care, and recommendations for the management of aSAH in special populations. It provides practical clinical guidance and recommendations for doctors and related professionals.


Assuntos
Aneurisma Roto , Aneurisma Intracraniano , Humanos , Aneurisma Intracraniano/terapia , Aneurisma Roto/terapia , China , Hemorragia Subaracnóidea/terapia , Hemorragia Subaracnóidea/diagnóstico , Prognóstico
13.
Zhonghua Yi Xue Za Zhi ; 104(17): 1486-1492, 2024 May 07.
Artigo em Zh | MEDLINE | ID: mdl-38706055

RESUMO

Objective: To investigate the clinical effect of over-the-top (OTT) reconstruction of the anterior cruciate ligament (ACL) combined with the modified Lemaire technique in one-stage ACL revision. Methods: It's a retrospective study. The clinical data of 37 patients who underwent one-stage revision of ACL using OTT combined with modified Lemaire technique from April 2020 to May 2023 in the Department of Sports Medicine of Xinhua Hospital Affiliated to Dalian University were retrospectively analyzed. There were 28 males and 9 females with a mean age of (32.7±5.7) years. The postoperative knee function and surgical revision effect were evaluated by subjective and objective evaluation indexes of the knee joint before and 3 months and 24 months after surgery. The subjective evaluation indexes included the International Knee Documentation Committee (IKDC) score, Lysholm score, and Tegner score; and the objective evaluation indexes included the anterior-posterior static displacement distance of the tibia, tibia-femur relative rotation angle, the Lachman test, the axial shift test, and the ratio of the loss of muscle strength of the lower limb. Results: At the final follow-up, all patients returned to pre-injury motor level, with significant improvements in IKDC scores (45.3±6.8 preoperatively, 67.5±4.7 and 93.2±2.3 at 3 months and 2 years after the operation, respectively), Lysholm scores (57.2±2.6 preoperatively, 72.6±2.9 and 89.7±3.7 at 3 months and 2 years after the operation, respectively), and Tegner scores (3.1±0.7 preoperatively, 4.9±0.6 and 5.8±1.3 at 3 months and 2 years after the operation, respectively) (all P<0.001). The anterior-posterior static displacement distance of the tibia reduced significantly [from (5.2±0.5) mm before the operation to (1.4±0.5) mm at 2 years postoperatively) (P<0.001)]; and the relative rotation angle of the tibia-femur restored to the normal physiological range, it was reduced from 6.2°±1.2° before the operation to 1.7°±0.3° 2 years after (P<0.001). The Lachman test and axial shift test at 2 years postoperatively were all negative. The muscle strength loss ratio of the affected lower limb was significantly better than that before the operation (P<0.001). Conclusion: The use of OTT reconstruction combined with modified Lemaire technique for revision of ACL in patients with ACL reconstruction failure can circumvent the tunnel problem for one-stage revision and better restore the stability and function of the knee joint, with ideal clinical results.


Assuntos
Reconstrução do Ligamento Cruzado Anterior , Humanos , Reconstrução do Ligamento Cruzado Anterior/métodos , Masculino , Feminino , Adulto , Estudos Retrospectivos , Resultado do Tratamento , Lesões do Ligamento Cruzado Anterior/cirurgia , Ligamento Cruzado Anterior/cirurgia , Articulação do Joelho/cirurgia
14.
Zhonghua Fu Chan Ke Za Zhi ; 59(1): 49-55, 2024 Jan 25.
Artigo em Zh | MEDLINE | ID: mdl-38228515

RESUMO

Objective: To investigate the clinical characteristics, treatments and fertility recovery of rudimentary horn pregnancy (RHP). Methods: The clinical data of 12 cases with RHP diagnosed and treated in Peking University Third Hospital from January 1, 2010 to December 31, 2022 were retrospectively analyzed. Clinical informations, diagnosis and treatments of RHP and the pregnancy status after surgery were analyzed. Results: The median age of 12 RHP patients was 29 years (range: 24-37 years). Eight cases of pregnancy in residual horn of uterus occurred in type Ⅰ residual horn of uterus, 4 cases occurred in type Ⅱ residual horn of uterus; among which 5 cases were misdiagnosed by ultrasound before surgery. All patients underwent excision of residual horn of uterus and affected salpingectomy. After surgery, 9 patients expected future pregnancy, and 3 cases of natural pregnancy, 2 cases of successful pregnancy through assisted reproductive technology. Four pregnancies resulted in live birth with cesarean section, and 1 case resulted in spontaneous abortion during the first trimester of pregnancy. No uterine rupture or ectopic pregnancy occurred in subsequent pregnancies. Conclusions: Ultrasonography could aid early diagnosis of RHP while misdiagnosis occurred in certain cases. Thus, a comprehensive judgment and decision ought to be made based on medical history, physical examination and assisted examination. Surgical exploration is necessary for diagnosis and treatment of RHP. For infertile patients, assisted reproductive technology should be applied when necessary. Caution to prevent the occurrence of pregnancy complications such as uterine rupture, and application of cesarean section to terminate pregnancy are recommended.


Assuntos
Aborto Espontâneo , Gravidez Cornual , Gravidez Ectópica , Ruptura Uterina , Gravidez , Humanos , Feminino , Adulto Jovem , Adulto , Cesárea/efeitos adversos , Estudos Retrospectivos , Gravidez Ectópica/diagnóstico por imagem , Gravidez Ectópica/cirurgia , Gravidez Cornual/diagnóstico , Gravidez Cornual/cirurgia , Útero/diagnóstico por imagem , Útero/cirurgia , Ruptura Uterina/etiologia
15.
J Synchrotron Radiat ; 30(Pt 1): 35-50, 2023 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-36601924

RESUMO

A promising accelerator light source mechanism called steady-state microbunching (SSMB) is being actively studied. With the combination of strong coherent radiation from microbunching and high repetition rate of a storage ring, high-average-power narrow-band radiation can be anticipated from an SSMB storage ring, with wavelengths ranging from THz to soft X-ray. Such a novel light source could provide new opportunities for accelerator photon science like high-resolution angle-resolved photoemission spectroscopy and industrial applications like extreme ultraviolet (EUV) lithography. In this paper, a theoretical and numerical study of the average and statistical properties of coherent radiation from SSMB are presented. The results show that 1 kW average-power quasi-continuous-wave EUV radiation can be obtained from an SSMB ring provided that an average current of 1 A and a microbunch train with bunch length of 3 nm can be formed at the radiator which is assumed to be an undulator. Together with the narrow-band feature, the EUV photon flux can reach 6 × 1015 photons s-1 within a 0.1 meV energy bandwidth, which is three orders of magnitude higher than that in a conventional synchrotron source and is appealing for fundamental condensed matter physics and other research. In this theoretical investigation, we have generalized the definition and derivation of the transverse form factor of an electron beam which can quantify the impact of its transverse size on coherent radiation. In particular, it has been shown that the narrow-band feature of SSMB radiation is strongly correlated with the finite transverse electron beam size. Considering the pointlike nature of electrons and quantum nature of radiation, the coherent radiation fluctuates from microbunch to microbunch, or for a single microbunch from turn to turn. Some important results concerning the statistical properties of SSMB radiation are presented, with a brief discussion on its potential applications, for example the beam diagnostics. The presented work is of value for the development of SSMB to better serve potential synchrotron radiation users. In addition, this also sheds light on understanding the radiation characteristics of free-electron lasers, coherent harmonic generation, etc.

16.
Phys Rev Lett ; 130(18): 185001, 2023 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-37204906

RESUMO

Propagation of high-current relativistic electron beam (REB) in plasma is relevant to many high-energy astrophysical phenomena as well as applications based on high-intensity lasers and charged-particle beams. Here, we report a new regime of beam-plasma interaction arising from REB propagation in medium with fine structures. In this regime, the REB cascades into thin branches with local density a hundred times the initial value and deposits its energy 2 orders of magnitude more efficiently than that in homogeneous plasma, where REB branching does not occur, of similar average density. Such beam branching can be attributed to successive weak scatterings of the beam electrons by the unevenly distributed magnetic fields induced by the local return currents in the skeletons of the porous medium. Results from a model for the excitation conditions and location of the first branching point with respect to the medium and beam parameters agree well with that from pore-resolved particle-in-cell simulations.

17.
Phys Rev Lett ; 131(14): 145003, 2023 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-37862653

RESUMO

We propose exploiting the superluminal plasma wake for coherent Cherenkov radiation by injecting a relativistic electron beam (REB) into a plasma with a slowly varying density up-ramp. Using three-dimensional particle-in-cell and far-field time-domain radiation simulations, we show that an isolated subcycle pulse is coherently emitted towards the Cherenkov angle by bubble-sheath electrons successively at the rear of the REB-induced superluminal plasma wake. A theoretical model based on a superluminal current dipole has been developed to interpret such coherent radiation, and agrees well with the simulation results. This radiation has ultrashort attosecond-scale duration and high intensity, and exhibits excellent directionality with ultralow angular divergence and stable carrier envelope phase. Its intensity increases with the square of the propagation length and its central frequency can be easily tuned over a wide range, from the far infrared to the ultraviolet.

18.
BMC Infect Dis ; 23(1): 289, 2023 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-37147607

RESUMO

BACKGROUND: The World Health Organization has reported that the treatment success rate of multi-drug resistance tuberculosis is approximately 57% globally. Although new drugs such as bedaquiline and linezolid is likely improve the treatment outcome, there are other factors associated with unsuccessful treatment outcome. The factors associated with unsuccessful treatment outcomes have been widely examined, but only a few studies have developed prediction models. We aimed to develop and validate a simple clinical prediction model for unsuccessful treatment outcomes in patients with multi-drug resistance pulmonary tuberculosis (MDR-PTB). METHODS: This retrospective cohort study was performed between January 2017 and December 2019 at a special hospital in Xi'an, China. A total of 446 patients with MDR-PTB were included. Least absolute shrinkage and selection operator (LASSO) regression and multivariate logistic regression were used to select prognostic factors for unsuccessful treatment outcomes. A nomogram was built based on four prognostic factors. Internal validation and leave-one-out cross-validation was used to assess the model. RESULTS: Of the 446 patients with MDR-PTB, 32.9% (147/446) cases had unsuccessful treatment outcomes, and 67.1% had successful outcomes. After LASSO regression and multivariate logistic analyses, no health education, advanced age, being male, and larger extent lung involvement were identified as prognostic factors. These four prognostic factors were used to build the prediction nomograms. The area under the curve of the model was 0.757 (95%CI 0.711 to 0.804), and the concordance index (C-index) was 0.75. For the bootstrap sampling validation, the corrected C-index was 0.747. In the leave-one-out cross-validation, the C-index was 0.765. The slope of the calibration curve was 0.968, which was approximately 1.0. This indicated that the model was accurate in predicting unsuccessful treatment outcomes. CONCLUSIONS: We built a predictive model and established a nomogram for unsuccessful treatment outcomes of multi-drug resistance pulmonary tuberculosis based on baseline characteristics. This predictive model showed good performance and could be used as a tool by clinicians to predict who among their patients will have an unsuccessful treatment outcome.


Assuntos
Tuberculose Resistente a Múltiplos Medicamentos , Tuberculose Pulmonar , Humanos , Masculino , Feminino , Estudos Retrospectivos , Modelos Estatísticos , Prognóstico , Resultado do Tratamento , Tuberculose Resistente a Múltiplos Medicamentos/tratamento farmacológico , Tuberculose Pulmonar/tratamento farmacológico , Resistência a Múltiplos Medicamentos
19.
Clin Radiol ; 78(9): e600-e607, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37258332

RESUMO

AIM: To investigate the predictive value of the combination of DEEPVESSEL-fractional flow reserve (DVFFR) and quantitative plaque analysis using coronary computed tomographic angiography (CCTA) for major adverse cardiac events (MACE). METHOD: In this retrospective study, data from 69 vessels from 58 consecutive patients were collected. These patients who underwent coronary angiography (CAG) with DVFFR were divided into MACE-positive and MACE-negative groups. DVFFR measurements were obtained from CCTA images acquired before CAG, and an FFR or DVFFR value ≤ 0.80 was considered haemodynamically significant. CCTA images were analysed quantitatively using automated software to obtain the following indices: total plaque volume (TPV) and burden (TPB), calcified plaque volume (CPV) and burden (CPB), non-calcified plaque volume (NCPV) and burden (NCPB), low-attenuation plaque (LAP), minimum lumen area (MLA), stenosis grade (SG) and lesion length (LL). Univariate and multivariate logistic regression, correlation, and receiver operating characteristic (ROC) analyses were used for statistical analysis. RESULTS: DVFFR was highly correlated with invasive FFR (R=0.728), and the Bland-Altman plot showed good agreement between DVFFR and FFR (95% CI: -0.109-0.087) on a per-vessel level. DVFFR showed a high diagnostic performance in identifying abnormal haemodynamic vessels, with an area under the ROC curve (AUC) of 0.984. In multivariate analysis, the following biomarkers were predictors of MACE: DVFFR ≤ 0.8, SG, TPB, NCPB, and LL values. The combination of the above independent risk factors yielded the most valuable prediction for MACE (AUC:0.888). CONCLUSIONS: DVFFR was highly correlated with FFR with satisfactory diagnostic accuracy. DVFFR, together with plaque analysis indices, yielded valuable predictions for MACE.


Assuntos
Doença da Artéria Coronariana , Estenose Coronária , Reserva Fracionada de Fluxo Miocárdico , Placa Aterosclerótica , Humanos , Angiografia Coronária/métodos , Angiografia por Tomografia Computadorizada/métodos , Estenose Coronária/diagnóstico por imagem , Estudos Retrospectivos , Valor Preditivo dos Testes , Prognóstico , Placa Aterosclerótica/diagnóstico por imagem , Placa Aterosclerótica/complicações , Doença da Artéria Coronariana/complicações
20.
Clin Radiol ; 78(5): e442-e450, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-36804273

RESUMO

AIM: To investigate the association between intracranial plaque characteristics and high-sensitivity C-reactive protein (hs-CRP) levels, and their combined effects on the occurrence of acute cerebral infarction (ACI). MATERIALS AND METHODS: One hundred and forty-three patients with recent ischaemic events in the territory of middle cerebral artery or basilar artery were enrolled and divided into the ACI group (n=93) and non-ACI group (n=50) according to clinical data and diffusion-weighting imaging (DWI) results. All recruited patients underwent high-resolution magnetic resonance imaging (MRI) to assess intracranial plaque characteristics, including plaque enhancement, standardised wall index, stenosis ratio, T1 hyperintense component, remodelling pattern, plaque area, plaque burden, and maximum wall thickness. hs-CRP levels were further grouped into the low group (<1 mg/l), the intermediate group (1-3 mg/l), and the high group (≥3 mg/l). Multivariate logistic regression and receiver operating characteristic curve were constructed to evaluate the association between intracranial plaque characteristics and hs-CRP levels, as well as their synergistic effects on determining the occurrence of ACI. RESULTS: High hs-CRP levels were associated with strong plaque enhancement (p<0.001, odds ratio [OR] = 7.497). Strong plaque enhancement (p=0.002, OR=2.109) and high hs-CRP levels (p=0.009, OR=3.893) were independently associated with the occurrence of ACI after adjustments for sex, age, and other traditional atherosclerotic risk factors. The combination of hs-CRP levels and strong plaque enhancement provided incremental information to determine ACI with an AUC of 0.823, which was significantly higher than that of strong plaque enhancement (0.711) and hs-CRP levels (0.686), respectively. CONCLUSION: High hs-CRP levels were associated with strong plaque enhancement. The synergistic effects of hs-CRP levels and strong plaque enhancement provided incremental effects on the occurrence of ACI.


Assuntos
Isquemia Encefálica , Placa Aterosclerótica , Acidente Vascular Cerebral , Humanos , Proteína C-Reativa/metabolismo , Relevância Clínica , Isquemia Encefálica/etiologia , Acidente Vascular Cerebral/complicações , Imageamento por Ressonância Magnética/efeitos adversos , Placa Aterosclerótica/diagnóstico por imagem , Placa Aterosclerótica/complicações , Infarto Cerebral/diagnóstico por imagem
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