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Magnetic topological insulators are narrow-gap semiconductor materials that combine non-trivial band topology and magnetic order1. Unlike their nonmagnetic counterparts, magnetic topological insulators may have some of the surfaces gapped, which enables a number of exotic phenomena that have potential applications in spintronics1, such as the quantum anomalous Hall effect2 and chiral Majorana fermions3. So far, magnetic topological insulators have only been created by means of doping nonmagnetic topological insulators with 3d transition-metal elements; however, such an approach leads to strongly inhomogeneous magnetic4 and electronic5 properties of these materials, restricting the observation of important effects to very low temperatures2,3. An intrinsic magnetic topological insulator-a stoichiometric well ordered magnetic compound-could be an ideal solution to these problems, but no such material has been observed so far. Here we predict by ab initio calculations and further confirm using various experimental techniques the realization of an antiferromagnetic topological insulator in the layered van der Waals compound MnBi2Te4. The antiferromagnetic ordering that MnBi2Te4 shows makes it invariant with respect to the combination of the time-reversal and primitive-lattice translation symmetries, giving rise to a â¤2 topological classification; â¤2 = 1 for MnBi2Te4, confirming its topologically nontrivial nature. Our experiments indicate that the symmetry-breaking (0001) surface of MnBi2Te4 exhibits a large bandgap in the topological surface state. We expect this property to eventually enable the observation of a number of fundamental phenomena, among them quantized magnetoelectric coupling6-8 and axion electrodynamics9,10. Other exotic phenomena could become accessible at much higher temperatures than those reached so far, such as the quantum anomalous Hall effect2 and chiral Majorana fermions3.
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OBJECTIVE: To determine the impact of nodal basin ultrasound (US) surveillance versus completion lymph node dissection (CLND) in children and adolescents with sentinel lymph node (SLN) positive melanoma. BACKGROUND: Treatment for children and adolescents with melanoma are extrapolated from adult trials. However, there is increasing evidence that important clinical and biological differences exist between pediatric and adult melanoma. METHODS: Patients ≤18 years diagnosed with cutaneous melanoma between 2010 and 2020 from 14 pediatric hospitals were included. Data extracted included demographics, histopathology, nodal basin strategies, surveillance intervals, and survival information. RESULTS: Of 252 patients, 90.1% (n=227) underwent SLN biopsy (SLNB), 50.9% (n=115) had at least 1 positive node. A total of 67 patients underwent CLND with 97.0% (n=65/67) performed after a positive SLNB. In contrast, 46 total patients underwent US observation of nodal basins with 78.3% (n=36/46) of these occurring after positive SLNB. Younger patients were more likely to undergo US surveillance (median age 8.5 y) than CLND (median age 11.3 y; P =0.0103). Overall, 8.9% (n=21/235) experienced disease recurrence: 6 primary, 6 nodal, and 9 distant. There was no difference in recurrence (11.1% vs 18.8%; P =0.28) or death from disease (2.2% vs 9.7%; P =0.36) for those who underwent US versus CLND, respectively. CONCLUSIONS: Children and adolescents with cutaneous melanoma frequently have nodal metastases identified by SLN. Recurrence was more common among patients with thicker primary lesions and positive SLN. No significant differences in oncologic outcomes were observed with US surveillance and CLND following the identification of a positive SLN.
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Melanoma , Linfonodo Sentinela , Neoplasias Cutâneas , Adulto , Humanos , Adolescente , Criança , Melanoma/diagnóstico por imagem , Melanoma/cirurgia , Melanoma/patologia , Neoplasias Cutâneas/diagnóstico por imagem , Neoplasias Cutâneas/cirurgia , Linfonodo Sentinela/patologia , Recidiva Local de Neoplasia/patologia , Excisão de Linfonodo , Biópsia de Linfonodo Sentinela , Estudos RetrospectivosRESUMO
We study the properties of bound states in waveguide-QED systems consisting of multiple giant atoms coupled to a coupled-resonator waveguide. Based on the general analytical expressions for these states and the corresponding energy spectra, we analyze in detail the threshold conditions for the appearance of bound states and the photon-mediated interactions between dressed atoms for different configurations. In addition, when multiple giant atoms are coupled to the waveguide, different types of interacting atomic chain can be obtained by manipulating the coupling configurations. Accordingly, the energy spectra of the bound states form metaband structures in the photonic band gaps. This makes the system a useful platform for quantum simulation and quantum information processing.
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Bose-Einstein condensation occurs at an appropriate density of bosonic particles, depending on their mass and temperature. The transition from the semiclassical paradigm of spin waves to the magnon Bose-Einstein condensed state (mBEC) was obtained experimentally with increasing magnon density. We used the Faraday rotation effect to study the spatial distribution of the magnon density and phase far from their excitation region. A coherent magnetization precession was observed throughout the sample, which indicates the formation of a magnon BEC. It is shown that this result under experimental conditions goes beyond the applicability of the Landau-Lifshitz-Gilbert semiclassical theory.
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We report the first search for dark sectors performed at the NA64 experiment employing a high energy muon beam and a missing energy-momentum technique. Muons from the M2 beamline at the CERN Super Proton Synchrotron with a momentum of 160 GeV/c are directed to an active target. The signal signature consists of a single scattered muon with momentum <80 GeV/c in the final state, accompanied by missing energy, i.e., no detectable activity in the downstream calorimeters. For a total dataset of (1.98±0.02)×10^{10} muons on target, no event is observed in the expected signal region. This allows us to set new limits on the remaining (m_{Z^{'}},g_{Z^{'}}) parameter space of a new Z^{'} (L_{µ}-L_{τ}) vector boson which could explain the muon (g-2)_{µ} anomaly. Additionally, our study excludes part of the parameter space suggested by the thermal dark matter relic abundance. Our results pave the way to explore dark sectors and light dark matter with muon beams in a unique and complementary way to other experiments.
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PURPOSE: Diabetes and dyslipidemia are among the most common chronic diseases with increasing global disease burdens, and they frequently occur together. The study aimed to investigate differences in the heritability of glycemic traits and serum lipid indicators and differences in overlapping genetic and environmental influences between them across age groups. METHODS: This study included 1189 twin pairs from the Chinese National Twin Registry and divided them into three groups: aged ≤ 40, 41-50, and > 50 years old. Univariate and bivariate structural equation models (SEMs) were conducted on glycemic indicators and serum lipid indicators, including blood glucose (GLU), glycated hemoglobin A1c (HbA1c), total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C), in the total sample and three age groups. RESULTS: All phenotypes showed moderate to high heritability (0.37-0.64). The heritability of HbA1c demonstrated a downward trend with age (HbA1c: 0.50-0.79), while others remained relatively stable (GLU: 0.55-0.62, TC: 0.58-0.66, TG: 0.50-0.63, LDL-C: 0.24-0.58, HDL-C: 0.31-0.57). The bivariate SEMs demonstrated that GLU and HbA1c were correlated with each serum lipid indicator (0.10-0.17), except HDL-C. Except for HbA1c and LDL-C, as well as HbA1c and HDL-C, differences in genetic correlations underlying glycemic traits and serum lipids between age groups were observed, with the youngest group showing a significantly higher genetic correlation than the oldest group. CONCLUSION: Across the whole adulthood, genetic influences were consistently important for GLU, TC, TG, LDL-C and HDL-C, and age may affect the shared genetic influences between glycemic traits and serum lipids. Further studies are needed to elucidate the role of age in the interactions of genes related to glycemic traits and serum lipids.
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Glicemia , Lipídeos , Adulto , Humanos , Pessoa de Meia-Idade , Causalidade , HDL-Colesterol/sangue , LDL-Colesterol/sangue , Fenótipo , Triglicerídeos/sangue , População do Leste Asiático , Hemoglobinas Glicadas , Lipídeos/sangueRESUMO
Objective: To investigate the clinical and genetic mutation characteristics of patients with primary hemophagocytic lymphohistiocytosis (HLH) and their impact on prognosis. Methods: Sixty-three primary HLH patients with complete medical records admitted and diagnosed at Beijing Friendship Hospital of Capital Medical University from January 2013 to December 2022 were selected. The patients' clinical and laboratory features, genetic and rapid immunological indicator characteristics, treatment outcomes and prognosis were retrospectively analyzed. Follow-up was up to June 30, 2023, with a median follow-up time [M (Q1, Q3)] of 47 (21, 76) months. Overall survival was analyzed using Kaplan-Meier survival curve, and prognostic factors were analyzed using Cox proportional hazards regression model. Results: Sixty-three primary HLH patients included 35 males and 28 females, with a median age [M (Q1, Q3)] of 17 (7, 27) years. Clinical manifestations at the initial diagnosis mainly included fever (93.7%, 59/63), splenomegaly (87.3%, 55/63), hemophagocytosis (65.1%, 41/63), hepatomegaly (52.4%, 33/63) and central nervous system (CNS) involvement (38.1%, 24/63). A total of 39 patients (61.9%) were diagnosed with EB virus (EBV) infection at initial diagnosis.PRF1 and UNC13D gene mutations were the most common mutations, and the highest frequency mutation site in the PRF1 gene was c.1349C>T, and that of UNC13D gene was c.2588G>A. A total of 76.2% (48/63) of patients had reduced activity of natural killer (NK) cells. Cytotoxic cell degranulation function was impaired or absent in 52.7% (29/55) of patients, of which 79.2% (19/24) of patients with primary HLH with defects in degranulation-related genes had impaired degranulation function. The 1-year and 3-year overall survival rates were 74.8% and 66.7%, respectively. Cox multivariate analysis suggested that peripheral blood EBV≥10 000 copies/ml (HR=3.523, 95%CI: 1.418-8.757, P=0.007) was the risk factor for prognosis. Conclusions: The main clinical manifestations of primary HLH patients at the initial diagnosis include fever, splenomegaly, hemophagocytosis, hepatomegaly, and CNS involvement. PRF1 and UNC13D are the most commonly mutated genes. High copy number EBV infection in peripheral blood is the risk factor for prognosis.
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Linfo-Histiocitose Hemofagocítica , Mutação , Humanos , Linfo-Histiocitose Hemofagocítica/genética , Linfo-Histiocitose Hemofagocítica/diagnóstico , Masculino , Prognóstico , Feminino , Estudos Retrospectivos , Adolescente , Criança , Adulto , Adulto Jovem , Perforina/genéticaRESUMO
Objective: To investigate the efficacy and safety of intravenous thrombolysis with Tenecteplase (TNK) in patients with post-awakening branch atheromatous disease (BAD). Methods: A retrospective collection was conducted on 178 patients with post-awakening BAD admitted to the Stroke Centre of Zhengzhou People's Hospital from January 2017 to June 2023, who had a mismatch in DWI/FLAIR on magnetic resonance imaging. The patients were divided into thrombolysis group (60 patients) and control group (118 patients) according to whether or not they were applied to intravenous thrombolysis by TNK. Propensity score matching (PSM) was used to pair and balance the confounding factors at 1â¶1 between the two groups, and the 90-d long-term prognosis of the patients was assessed using the modified Rankin Scale (mRS) and the Barthel Index (BI). The National Institutes of Health Stroke Scale (NIHSS) score was used to compare the early neurological changes between the two groups.The differences in clinical outcomes were compared between the two groups. Results: Fifty-two pairs of patients, 65 males and 39 females, aged (60±9) years, were successfully matched by PSM. The thrombolysis group had lower NIHSS score than that of the control group at 24 h, 7 d, 14 d after treatment or at discharge [3(2, 5) vs 4(3, 7), 3(2, 5) vs 4(3, 5), and 2(1, 4) vs 3(2, 4)], and shorter hospital stay than that of the control group [9(7, 12) d vs 11(9, 13) d], and at the same time, the thrombolysis group was less likely to experience early neurological deterioration (END) [9.6% (5/52) vs 28.9% (15/52)], and the proportion of 90 d mRS≤1, mRS≤2, and BI scores were higher than those in the control group [63.5% (33/52) vs 30.8% (16/52), 82.7% (43/52) vs 59.6% (31/52), and (91±8) points vs (82±8) points ], all differences were statistically significant (P<0.05). The percentage of mRS≥4 points was higher in the control group than that in the thrombolysis group [23.1% (12/52) vs 7.7% (4/52)]. One case of intracranial haemorrhage occurred in the thrombolysis group, and 1 case in the control group died of pulmonary infection within 90 d of follow-up, with a case-fatality rate of 1.9% (1/52). Conclusion: In the patients with post-awakening BAD screened by MRI, TNK intravenous thrombolysis can significantly reduce the risk of END, improving long-term prognosis and has a high safety.
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Fibrinolíticos , Tenecteplase , Terapia Trombolítica , Humanos , Feminino , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Tenecteplase/administração & dosagem , Tenecteplase/uso terapêutico , Fibrinolíticos/uso terapêutico , Fibrinolíticos/administração & dosagem , Administração Intravenosa , Resultado do Tratamento , Acidente Vascular Cerebral/tratamento farmacológico , Idoso , Ativador de Plasminogênio Tecidual/uso terapêutico , Ativador de Plasminogênio Tecidual/administração & dosagem , Prognóstico , Pontuação de PropensãoRESUMO
Objective: To evaluate the long-term outcomes of lower extremity arteriovenous graft (AVG) in hemodialysis patients. Methods: Hemodialysis patients with lower extremity AVG from August 2015 to July 2023 in the Department of Vascular Surgery, Longhua Hospital, Shanghai University of Traditional Chinese Medicine were enrolled. Therapeutic effects and complications of AVG were retrospectively analyzed. Results: A total of 83 cases aged (58.9±13.3) years were enrolled, including 25 males and 58 females. The success rate of the operation was 100% (83/83), and no perioperative complications occurred. The follow-up time [M (Q1, Q3)] was 38.4 (22.6, 55.3) months, with a follow-up rate of 92.8% (77/83). There were 9 cases (11.7%) of puncture site infection, 5 cases (6.5%) of pseudoaneurysm, 2 cases (2.6%) of seroma, 3 cases (3.9%) of lower limb ischemia, 48 cases (62.3%) of stenosis and 24 cases (31.2%) of thrombosis during the follow-up period. The 6-month, 1-year, 2-year, 3-year and 5-year primary patency rates after surgery were 78.9%, 61.2%, 39.0%, 27.0% and 16.3%, respectively, assisted primary patency rates were 93.5%, 82.5%, 74.9%, 68.0% and 53.0%, respectively, and secondary patency rates were 96.1%, 94.7%, 93.1%, 91.3% and 75.3%, respectively. Conclusion: For patients whose vascular resources of upper limbs are exhausted, lower extremity AVG is a safe and effective hemodialysis vascular access.
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Derivação Arteriovenosa Cirúrgica , Extremidade Inferior , Diálise Renal , Humanos , Masculino , Feminino , Pessoa de Meia-Idade , Extremidade Inferior/irrigação sanguínea , Estudos Retrospectivos , Idoso , Resultado do Tratamento , Grau de Desobstrução VascularRESUMO
We examined the effects of elevated temperatures and biocides on survivability of food isolates of Cronobacter spp. (C. sakazakii) and concomitant enterobacteriaceae obtained in microbiological control of infant nutrition products. Increased resistance of certain strains of Cronobacter, Enterobacter cloacae, and Pantoea spp. to thermal processing was revealed. Salmonella, Pantoea, and Cronobacter bacteria were least sensitive to antimicrobial action of chlorine-containing agents. The above properties varied in the strains of the same species. Specifically, only two of three examined isolates of Cronobacter spp. demonstrated lower sensitivity to heat in comparison with the enterobacterial test-cultures of other species.
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Cloro , Cronobacter , Desinfetantes , Microbiologia de Alimentos , Desinfetantes/farmacologia , Cronobacter/efeitos dos fármacos , Cronobacter/isolamento & purificação , Cloro/farmacologia , Enterobacteriaceae/efeitos dos fármacos , Enterobacteriaceae/isolamento & purificação , Temperatura Alta , Humanos , Cronobacter sakazakii/efeitos dos fármacos , Cronobacter sakazakii/isolamento & purificação , Testes de Sensibilidade Microbiana , Salmonella/efeitos dos fármacos , Salmonella/isolamento & purificação , Enterobacter cloacae/efeitos dos fármacos , Enterobacter cloacae/isolamento & purificaçãoRESUMO
A morphological analysis of the liver of Wistar rats was performed 2 months after a single intravenous injection of porous silicon particles of different sizes (60-80, 250-300, and 500-600 nm; 2 mg/ml, 1 ml). Histological, immunohistochemical, and electron microscopic methods showed the development of CD68+ granulomas in all experimental groups. Injection of 60-80-nm porous silicon particles led to the formation of single large granulomas (>2000 µm2), while 500-600-nm nanoparticles caused the formation of numerous smaller granulomas. The mechanism of involution of granulomas by apoptosis of Kupffer cells and the absence of subsequent connective tissue remodeling of the organ tissue is shown.
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Fígado , Silício , Ratos , Animais , Ratos Wistar , Fígado/patologia , Granuloma/induzido quimicamente , Granuloma/patologia , Células de KupfferRESUMO
Objective: To investigate the annual growth rate of obesity prevalence of residents aged 18 and above in China and prevention keypoints for target populations from 2013 to 2018. Methods: This was a cross-sectional study. Subjects from China Chronic Disease and Risk Factor Surveillance project in 2013 and 2018 were included. The prevalence of obesity and growth rate in 31 provinces (autonomous regions and municipalities) in China were collected through survey questionnaires and on-site measurements. Other demographic data such as the proportion of obesity control measures, diet, exercise and drug use was also analyzed. Obesity among adults was defined as body mass index≥28.0 kg/m². Results: A total of 174 736 residents, aged (51.5±14.2) years, which included 74 704 (42.8%) males were recruited in 2013, and 179 125 residents, aged (55.1±13.8) years, which included 79 337 (44.3%) males were included in 2018. The average annual increase rate of adult obesity prevalence in China from 2013 to 2018 was 3.2% (uncertainty interval (UI) 2.7%-3.6%), and the average increase rate of obesity prevalence among men (5.2% (UI 4.6%-5.9%)) was higher than that of women (0.9% (UI 0.5%-1.3%)). For subgroups analysis, the average increase rate of obesity prevalence among residents aged 18 to 29 (7.4% (UI 6.9%-7.9%)), education level beyond college degree (6.3% (UI 5.5%-7.1%)), and unmarried population (11.2% (UI 10.2%-12.1%)) were higher than that of other subgroups between 2013 and 2018. The residents in Hainan province showed the highest average annual growth rate of obesity. With the exception of Shanxi, Hunan, Gansu and Ningxia province, the annual growth rate of obesity prevalence among adults increased in all other provinces (autonomous regions and municipalities) from 2013 to 2018. For the obese population, the proportion of people who took weight control measures increased from 22.6% in 2013 to 32.7% in 2018. Conclusions: The prevalence of obesity growth characteristics in subpopulations and regions in China are obviously different. Accordingly the focus points of obesity prevention and control in different regions should have their own emphasis.
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Obesidade , Adulto , Masculino , Humanos , Feminino , Prevalência , Estudos Transversais , Obesidade/epidemiologia , China/epidemiologia , Fatores de RiscoRESUMO
The main problem in microsurgical resection of spinal cord tumors is excessive surgical aggression. The last one often leads to unsatisfactory clinical and neurological outcomes. Laser fluorescence spectroscopy is a modern neurosurgical approach to distinguish tumor boundaries even if standard visible fluorescence techniques are ineffective. OBJECTIVE: To evaluate the effectiveness of laser fluorescence spectroscopy alone or in combination with visual 5-ALA fluorescence for improvement of safety and quality of resection, as well as intraoperative diagnosis. MATERIAL AND METHODS: Searching for literature data was carried out in accordance with the PRISMA recommendations. The authors reviewed articles independently of each other. These data were systematized. RESULTS: Laser fluorescence spectroscopy is valuable to identify fragments of intramedullary ependyomas in 86% of cases, while visual fluorescence only in 81% of cases. Advisability of this technique for low-grade astrocytomas is still unclear and requires further study. Its effectiveness is 87.5% for extramedullary meningiomas. Neuromas do not accumulate 5-ALA. In addition, this method can be used to determine the boundaries of intradural metastatic lesions. CONCLUSION: 5-ALA fluorescence is a safe and useful intraoperative method for identifying tumor tissue and resection margins in patients with intramedullary or infiltrative extramedullary spinal cord tumors. Visual fluorescence combined with laser spectroscopy is a perspective method for intraoperative visualization of tumor remnants. This approach can improve safety and postoperative outcomes while maintaining resection quality.
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Neoplasias da Medula Espinal , Neoplasias da Coluna Vertebral , Humanos , Neoplasias da Coluna Vertebral/cirurgia , Espectrometria de Fluorescência , Neoplasias da Medula Espinal/diagnóstico por imagem , Neoplasias da Medula Espinal/cirurgia , Procedimentos Neurocirúrgicos/métodos , LasersRESUMO
The article presents a case of pharyngeal dysphagia and obstructive sleep apnea syndrome caused by degenerative-dystrophic changes in the cervical spine with the formation of large cervical osteophytes at the C3-C6 level. Osteophytes caused deformation of the posterior wall of the hypopharynx and narrowing of its lumen by 20-25% from the level of the arytenoid cartilages to the upper parts of the epiglottis. CT scan also showed the intervertebral disc heights lost, as well as osteophytes at the posterolateral margins of the vertebral bodies (disc osteophyte complex). Osteosclerosis in combination with facet arthrosis caused spinal and foraminal stenosis.
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Vértebras Cervicais , Transtornos de Deglutição , Humanos , Vértebras Cervicais/diagnóstico por imagem , Transtornos de Deglutição/etiologia , Transtornos de Deglutição/diagnóstico , Transtornos de Deglutição/fisiopatologia , Apneia Obstrutiva do Sono/diagnóstico , Apneia Obstrutiva do Sono/fisiopatologia , Apneia Obstrutiva do Sono/complicações , Apneia Obstrutiva do Sono/etiologia , Tomografia Computadorizada por Raios X/métodos , Resultado do TratamentoRESUMO
The article presents a case of chronic odontogenic maxillary sinusitis and the results of its surgical treatment. The cause of the sinusitis, confirmed by the results of X-ray and pathohistological studies, was an inflammatory process affecting the bone tissue around the implant, installed in the place of the upper first molar which was accompanied by the development of an oroantral fistula. During the surgical intervention, the communication between the oral cavity and the maxillary sinus was eliminated, and the implant with the abutment, which was entirely in its cavity, was also removed.
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Implantes Dentários , Sinusite Maxilar , Humanos , Sinusite Maxilar/diagnóstico , Sinusite Maxilar/etiologia , Sinusite Maxilar/cirurgia , Implantes Dentários/efeitos adversos , Seio Maxilar/diagnóstico por imagem , Seio Maxilar/cirurgia , Fístula Bucoantral/diagnóstico , Fístula Bucoantral/etiologia , Fístula Bucoantral/cirurgia , Doença CrônicaRESUMO
BACKGROUND: The isolation of cell-free DNA (cfDNA) from the bloodstream can be used to detect and analyze somatic alterations in circulating tumor DNA (ctDNA), and multiple cfDNA-targeted sequencing panels are now commercially available for Food and Drug Administration (FDA)-approved biomarker indications to guide treatment. More recently, cfDNA fragmentation patterns have emerged as a tool to infer epigenomic and transcriptomic information. However, most of these analyses used whole-genome sequencing, which is insufficient to identify FDA-approved biomarker indications in a cost-effective manner. PATIENTS AND METHODS: We used machine learning models of fragmentation patterns at the first coding exon in standard targeted cancer gene cfDNA sequencing panels to distinguish between cancer and non-cancer patients, as well as the specific tumor type and subtype. We assessed this approach in two independent cohorts: a published cohort from GRAIL (breast, lung, and prostate cancers, non-cancer, n = 198) and an institutional cohort from the University of Wisconsin (UW; breast, lung, prostate, bladder cancers, n = 320). Each cohort was split 70%/30% into training and validation sets. RESULTS: In the UW cohort, training cross-validated accuracy was 82.1%, and accuracy in the independent validation cohort was 86.6% despite a median ctDNA fraction of only 0.06. In the GRAIL cohort, to assess how this approach performs in very low ctDNA fractions, training and independent validation were split based on ctDNA fraction. Training cross-validated accuracy was 80.6%, and accuracy in the independent validation cohort was 76.3%. In the validation cohort where the ctDNA fractions were all <0.05 and as low as 0.0003, the cancer versus non-cancer area under the curve was 0.99. CONCLUSIONS: To our knowledge, this is the first study to demonstrate that sequencing from targeted cfDNA panels can be utilized to analyze fragmentation patterns to classify cancer types, dramatically expanding the potential capabilities of existing clinically used panels at minimal additional cost.
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Ácidos Nucleicos Livres , DNA Tumoral Circulante , Neoplasias da Próstata , Masculino , Humanos , DNA Tumoral Circulante/genética , Mutação , Neoplasias da Próstata/genética , Ácidos Nucleicos Livres/genética , Perfilação da Expressão Gênica , Biomarcadores Tumorais/genéticaRESUMO
Magnons have demonstrated enormous potential for the next generation of information technology and quantum computing. In particular, the coherent state of magnons resulting from their Bose-Einstein condensation (mBEC) is of great interest. Typically, mBEC is formed in the magnon excitation region. Here we demonstrate for the first time by optical methods the permanent existence of mBEC at large distances from the magnon excitation region. The homogeneity of the mBEC phase is also demonstrated. The experiments were carried out on films of yttrium iron garnet magnetized perpendicular to the surface and at room temperature. We use the method described in this article to develop coherent magnonics and quantum logic devices.
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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.
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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.
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Thermal dark matter models with particle χ masses below the electroweak scale can provide an explanation for the observed relic dark matter density. This would imply the existence of a new feeble interaction between the dark and ordinary matter. We report on a new search for the sub-GeV χ production through the interaction mediated by a new vector boson, called the dark photon A^{'}, in collisions of 100 GeV electrons with the active target of the NA64 experiment at the CERN SPS. With 9.37×10^{11} electrons on target collected during 2016-2022 runs NA64 probes for the first time the well-motivated region of parameter space of benchmark thermal scalar and fermionic dark matter models. No evidence for dark matter production has been found. This allows us to set the most sensitive limits on the A^{'} couplings to photons for masses m_{A^{'}}â²0.35 GeV, and to exclude scalar and Majorana dark matter with the χ-A^{'} coupling α_{D}≤0.1 for masses 0.001â²m_{χ}â²0.1 GeV and 3m_{χ}≤m_{A^{'}}.