Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 123
Filtrar
1.
Nature ; 574(7777): 223-227, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31597974

RESUMO

High-entropy alloys are a class of materials that contain five or more elements in near-equiatomic proportions1,2. Their unconventional compositions and chemical structures hold promise for achieving unprecedented combinations of mechanical properties3-8. Rational design of such alloys hinges on an understanding of the composition-structure-property relationships in a near-infinite compositional space9,10. Here we use atomic-resolution chemical mapping to reveal the element distribution of the widely studied face-centred cubic CrMnFeCoNi Cantor alloy2 and of a new face-centred cubic alloy, CrFeCoNiPd. In the Cantor alloy, the distribution of the five constituent elements is relatively random and uniform. By contrast, in the CrFeCoNiPd alloy, in which the palladium atoms have a markedly different atomic size and electronegativity from the other elements, the homogeneity decreases considerably; all five elements tend to show greater aggregation, with a wavelength of incipient concentration waves11,12 as small as 1 to 3 nanometres. The resulting nanoscale alternating tensile and compressive strain fields lead to considerable resistance to dislocation glide. In situ transmission electron microscopy during straining experiments reveals massive dislocation cross-slip from the early stage of plastic deformation, resulting in strong dislocation interactions between multiple slip systems. These deformation mechanisms in the CrFeCoNiPd alloy, which differ markedly from those in the Cantor alloy and other face-centred cubic high-entropy alloys, are promoted by pronounced fluctuations in composition and an increase in stacking-fault energy, leading to higher yield strength without compromising strain hardening and tensile ductility. Mapping atomic-scale element distributions opens opportunities for understanding chemical structures and thus providing a basis for tuning composition and atomic configurations to obtain outstanding mechanical properties.

2.
Eur Radiol ; 34(3): 1624-1634, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37658137

RESUMO

OBJECTIVES: The Alberta Stroke Program Early CT Score (ASPECTS) is a semi-quantitative method to evaluate the severity of early ischemic change on non-contrast computed tomography (NCCT) in patients with acute ischemic stroke (AIS). In this work, we propose an automated ASPECTS method based on large cohort of data and machine learning. METHODS: For this study, we collected 3626 NCCT cases from multiple centers and annotated directly on this dataset by neurologists. Based on image analysis and machine learning methods, we constructed a two-stage machine learning model. The validity and reliability of this automated ASPECTS method were tested on an independent external validation set of 300 cases. Statistical analyses on the total ASPECTS, dichotomized ASPECTS, and region-level ASPECTS were presented. RESULTS: On an independent external validation set of 300 cases, for the total ASPECTS results, the intraclass correlation coefficient between automated ASPECTS and expert-rated was 0.842. The agreement between ASPECTS threshold of ≥ 6 versus < 6 using a dichotomized method was moderate (κ = 0.438, 0.391-0.477), and the detection rate (sensitivity) was 86.5% for patients with ASPECTS threshold of ≥ 6. Compared with the results of previous studies, our method achieved a slight lead in sensitivity (67.8%) and AUC (0.845), with comparable accuracy (78.9%) and specificity (81.2%). CONCLUSION: The proposed automated ASPECTS method driven by a large cohort of NCCT images performed equally well compared with expert-rated ASPECTS. This work further demonstrates the validity and reliability of automated ASPECTS evaluation method. CLINICAL RELEVANCE STATEMENT: The automated ASPECTS method proposed by this study may help AIS patients to receive rapid intervention, but should not be used as a stand-alone diagnostic basis. KEY POINTS: NCCT-based manual ASPECTS scores were poorly consistent. Machine learning can automate the ASPECTS scoring process. Machine learning model design based on large cohort data can effectively improve the consistency of ASPECTS scores.


Assuntos
Isquemia Encefálica , AVC Isquêmico , Acidente Vascular Cerebral , Humanos , Isquemia Encefálica/diagnóstico por imagem , Alberta , Reprodutibilidade dos Testes , Acidente Vascular Cerebral/diagnóstico por imagem , Aprendizado de Máquina , Estudos Retrospectivos
3.
Artigo em Inglês | MEDLINE | ID: mdl-37803887

RESUMO

BACKGROUND: Previous study has shown that a brief cognitive-behavioral prevention insomnia program could reduce 71% risk of developing insomnia among at-risk adolescents. This study aimed to evaluate the differential response to insomnia prevention in subgroups of at-risk adolescents. METHODS: Adolescents with a family history of insomnia and subthreshold insomnia symptoms were randomly assigned to a 4-week insomnia prevention program or nonactive control group. Assessments were conducted at baseline, 1 week, and 6- and 12-month after the intervention. Baseline sleep, daytime, and mood profiles were used to determine different subgroups by using latent class analysis (LCA). Analyses were conducted based on the intention-to-treat approach. RESULTS: LCA identified three subgroups: (a) insomnia symptoms only, (b) insomnia symptoms with daytime sleepiness and mild anxiety, and (c) insomnia symptoms with daytime sleepiness, mild anxiety, and depression. The incidence rate of insomnia disorder over the 12-month follow-up was significantly reduced for adolescents receiving intervention in subgroup 3 compared with the controls (hazard ratio [HR] = 0.37; 95% confidence interval [CI]: 0.13-0.99; p = .049) and marginally for subgroup 2 (HR = 0.14; 95% CI: 0.02-1.08; p = .059). In addition, adolescents who received intervention in subgroups 2 and 3 had a reduced risk of excessive daytime sleepiness (subgroup 2: adjusted OR [AdjOR] = 0.45, 95% CI: 0.23-0.87; subgroup 3: AdjOR = 0.32, 95% CI: 0.13-0.76) and possible anxiety (subgroup 2: AdjOR = 0.47, 95% CI: 0.27-0.82; subgroup 3: AdjOR = 0.33, 95% CI: 0.14-0.78) compared with the controls over the 12-month follow-up. CONCLUSIONS: Adolescents at risk for insomnia can be classified into different subgroups according to their psychological profiles, which were associated with differential responses to the insomnia prevention program. These findings indicate the need for further phenotyping and subgrouping at-risk adolescents to develop personalized insomnia prevention.

4.
Ophthalmic Res ; 66(1): 1114-1127, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37490883

RESUMO

BACKGROUND: Phototherapeutic keratectomy (PTK) has been increasingly used to treat severe recurrent corneal erosion syndrome (RCES) patients who do not respond to other treatments. However, the efficacy and complication of each study are currently uncertain due to varying rates. OBJECTIVES: The objective of this study was to investigate the safety and efficacy of the PTK for recurrent corneal erosions. METHODS: This article performed a systematic literature research in Cochrane, Embase, PubMed, Scopus, and the Web of Science for the literature on PTK treatment of RCES until December 20, 2022. The extracted data including recurrence rate and the adverse event rate were used for meta-analysis. RESULTS: The recurrence rate was 18% (95% CI, 13%-24%) (129/700 eyes). Subgroup analysis showed that the RCE recurrence was 17% (95% CI, 9%-24%) after trauma and 22% (95% CI, 11%-32%) in the corneal dystrophy group. Treatment-related adverse events included subepithelial haze, hyperopic shift, and decrease of the best spectacle-corrected visual acuity. In this study, the incidence of these events was 13% (95% CI, 6%-21%), 20% (95% CI, 11%-28%), and 11% (95% CI, 5%-16%), respectively. CONCLUSIONS: PTK represented a valuable treatment option for patients with recurrent corneal erosions, especially those with traumatic injuries, which had minimal side effects.


Assuntos
Doenças da Córnea , Distrofias Hereditárias da Córnea , Úlcera da Córnea , Ceratectomia Fotorrefrativa , Humanos , Lasers de Excimer/uso terapêutico , Seguimentos , Acuidade Visual , Distrofias Hereditárias da Córnea/complicações , Distrofias Hereditárias da Córnea/cirurgia , Córnea/cirurgia , Recidiva , Resultado do Tratamento , Doenças da Córnea/cirurgia
5.
J Geriatr Psychiatry Neurol ; 35(2): 215-222, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-35130783

RESUMO

OBJECTIVE: To examine the epidemiology of sense of alienation (SoA) and its associations with depressive symptoms and poor sleep quality (PSQ) in Chinese older adults who experienced lockdown during the COVID-19 pandemic. BACKGROUND: There is a dearth of data on SoA in older adults during the COVID-19 pandemic. METHODS: Altogether, 543 community-dwelling older adults (50+ years) were recruited via the three-tier mental health network in Wuhan, China, and completed an online questionnaire in April 2020, the first month after the reopening of Wuhan. SoA, depressive symptoms, and sleep quality were measured by using the General Social Alienation Scale, Depression Anxiety and Stress Scale, and a single standardized question, respectively. RESULTS: The prevalence of SoA was 52.3% (95% confidence interval: 48.1-56.5%). Factors associated with higher levels of SoA were religious belief (ß = 1.960, P = .024), monthly family income<4000 RMB (ß = 1.405, P = .022), unemployment (ß = 1.217, P = .039), fair or poor physical health (ß = 2.202, P = .002), never and sometimes receiving community support (ß = 2.297, P < .001 and ß = 3.417, P < .001), perceiving a low possibility of a cure for COVID-19 (ß = 2.379, P < .001), and affirmative and unsure fear of COVID-19 patients (ß = 2.025, P = .007 and ß = 1.101, P = .027). After adjusting for sociodemographic and pandemic-related variables, a one-SD increment in the SoA score was significantly associated with depressive symptoms (Odd Ratio [OR] = 5.59, P < .001) and poor sleep quality (Odd Ratio = 2.00, P < .001). CONCLUSION: Over half of the older adults who experienced lockdown felt alienated, and SoA was independently associated with their depressive symptoms and PSQ. Efforts are warranted to address SoA in older adults who experienced lockdown during the pandemic.


Assuntos
COVID-19 , Depressão , Idoso , Ansiedade/epidemiologia , Ansiedade/psicologia , COVID-19/epidemiologia , China/epidemiologia , Controle de Doenças Transmissíveis , Depressão/epidemiologia , Depressão/psicologia , Humanos , Pandemias , SARS-CoV-2 , Qualidade do Sono
6.
World J Surg Oncol ; 20(1): 316, 2022 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-36171591

RESUMO

BACKGROUND: PDZ-binding kinase/T-lymphokine-activated killer cell-derived protein kinase (PBK/TOPK) is a potential prognostic indicator for patients with breast cancer. The objective of the present study was to explore the relationship between PBK/TOPK expression and clinicopathological indicators as well as the survival of patients with breast cancer. METHODS: Immunohistochemical staining was used to detect the expression of PBK/TOPK in 202 cases of breast cancer tissues. The relationship between PBK/TOPK and clinicopathological parameters was evaluated using Spearman's rank-order correlation. The difference in PBK/TOPK expression among different molecular types was analyzed with the chi-square test. Kaplan-Meier analysis was used to create a survival curve and the log rank test was used to analyze the overall survival (OS) and disease-free survival (DFS). Prognostic correlation was assessed using univariate and multivariate Cox regression analyses. RESULTS: Among 202 breast cancer samples, PBK/TOPK was expressed ("+" and "++") in 182 samples (90.1%). In addition, the histological grade, TNM stages, lymph node metastasis, estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER-2), and Ki-67 were positively associated with PBK/TOPK expression. With regard to the molecular type, the expression of PBK/TOPK is different. The expression level of PBK/TOPK was negatively correlated with both the OS and DFS of breast cancer patients. The difference in the above results is meaningful (P < 0.05). CONCLUSIONS: PBK/TOPK is overexpressed in breast cancer, and the expression is closely related to the clinicopathological characteristics of the disease. Breast cancer patients with high expression of PBK/TOPK have a poor prognosis. Therefore, healthcare providers can optimize breast cancer management using this indicator.


Assuntos
Neoplasias da Mama , Receptores de Progesterona , Feminino , Humanos , Antígeno Ki-67 , Quinases de Proteína Quinase Ativadas por Mitógeno/metabolismo , Prognóstico , Receptores de Estrogênio , Estudos Retrospectivos
7.
J Nurs Manag ; 30(8): 3891-3899, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-35213935

RESUMO

OBJECTIVES: This study aims to understand the current situation and multiple factors affecting the core competence specializing in the maternal, neonatal and under-five nursing in China. BACKGROUND: Highly skilled nurses and midwives are essential worldwide for achieving the Sustainable Development Goals, especially in low- and middle-income countries like China, due to the overwhelming COVID-19 crisis. METHOD: The 890 nurses and midwives from 12 hospitals were investigated in this cross-sectional study, with two questionnaires: the sociodemographic information and competency inventory for the registered nurses. RESULTS: The participants reported a mean total score of 193.78 (±42.19) out of 220 and lowest in critical thinking and research ability (3.01 ± 0.82). The professional title, level, marital status, relationship quality, highest qualification, experience in specialist nurse training, participation in scientific research projects and publishing papers were the influencing factors (P < .05). CONCLUSIONS: The respondents' core competence needs improvement, especially critical regarding thinking and research ability. In addition, marriage and good or excellent relationship quality are factors that can potentially improve competence. IMPLICATIONS FOR NURSING MANAGEMENT: Targeted interventions for higher core nursing competence need to be implemented, especially focusing on nurses' marital status and emotional support from partners.


Assuntos
COVID-19 , Tocologia , Enfermeiras e Enfermeiros , Recém-Nascido , Gravidez , Humanos , Feminino , Tocologia/educação , Estudos Transversais , COVID-19/epidemiologia , Competência Profissional , Inquéritos e Questionários , Competência Clínica
8.
J Minim Invasive Gynecol ; 28(6): 1140, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33333236

RESUMO

OBJECTIVE: To present an innovative transumbilical laparoendoscopic single-site (TU-LESS) extraperitoneal approach for lymphadenectomy in a patient with advanced cervical carcinoma. DESIGN: Demonstration of the novel technique through video. SETTING: In advanced cervical cancer, determining the status of the para-aortic lymph nodes is essential because extended-field radiologic therapy is recommended for a patient with positive para-aortic lymph nodes [1]. Nonetheless, the sensitivity and specificity of currently available imaging workup for positive lymph nodes are limited. Surgical staging enables precise evaluation. However, laparotomy has potential wound complications and leads to treatment delay. Multiport laparoscopic transperitoneal and extraperitoneal approaches limit surgeons' ability to reach the para-aortic area or obturator fossa in the same operation [2]. Thus, we take full use of these approaches' advantages and avoid their disadvantages to design a promising minimally invasive surgery approach [3]. INTERVENTIONS: Para-aortic and obturator lymphadenectomy through the TU-LESS extraperitoneal approach was successfully performed without complications. The patient recovered quickly and received subsequent concurrent chemoradiation on schedule. CONCLUSION: TU-LESS extraperitoneal para-aortic lymphadenectomy provides satisfactory exposure and easy access to both the para-aortic area and obturator fossa. In addition, the bowels are uplifted by an extraperitoneal air cushion to achieve excellent exposure and reduce the risk of bowel injury. With quick recovery, the patient could start accurate radiation treatment promptly.


Assuntos
Laparoscopia , Neoplasias do Colo do Útero , Feminino , Humanos , Excisão de Linfonodo , Linfonodos/patologia , Linfonodos/cirurgia , Procedimentos Cirúrgicos Minimamente Invasivos , Estadiamento de Neoplasias , Neoplasias do Colo do Útero/patologia , Neoplasias do Colo do Útero/cirurgia
9.
Nutr J ; 19(1): 107, 2020 09 23.
Artigo em Inglês | MEDLINE | ID: mdl-32967680

RESUMO

BACKGROUD: Chromium has been suggested playing a role in alleviating diabetes, insulin resistance and lipid anomalies, but the effect on metabolic syndrome (MetS) in humans remains controversial. METHODS: We conducted a matched case-control study in a Chinese population, involving 2141 MetS cases and 2141 healthy controls, which were 1:1 matched by age (±2 years) and sex. Plasma chromium was measured by inductively coupled plasma mass spectrometry. RESULTS: Plasma chromium levels were lower in MetS group than in control group (mean: 4.36 µg/L and 4.66 µg/L, respectively, P < 0.001), and progressively decreased with the number of MetS components (P for trend < 0.001). After adjustment for potential confounding factors, the odds ratios (95% confidence intervals) for MetS across increasing quartiles of plasma chromium levels were 1 (reference), 0.84 (0.67-1.05), 0.76 (0.61-0.95), and 0.62 (0.49-0.78), respectively (P for trend < 0.001). For the components of MetS (high waist circumference, high triglycerides and high blood glucose), the odds ratios (95% confidence intervals) of the highest quartiles were 0.77 (0.61-0.95), 0.67 (0.55-0.80), and 0.53 (0.44-0.64), respectively (P for trend < 0.05). CONCLUSIONS: Our results indicated that plasma chromium levels were inversely associated with MetS in Chinese adults. The association may be explained by the relations between plasma chromium levels and high waist circumference, and the triglycerides and blood glucose levels.


Assuntos
Síndrome Metabólica , Adulto , Glicemia , Índice de Massa Corporal , Estudos de Casos e Controles , China/epidemiologia , Cromo , Estudos Transversais , Humanos , Síndrome Metabólica/epidemiologia , Fatores de Risco , Triglicerídeos , Circunferência da Cintura
10.
J Minim Invasive Gynecol ; 27(7): 1471-1472, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31926301

RESUMO

OBJECTIVE: Minimally invasive surgery (MIS) for radical hysterectomy (RH) has been reported with inferior oncologic outcomes in the New England Journal of Medicine [1,2]. Some studies have suggested that the no-touch technique may be a useful procedure to prevent tumor spillage and improve survival. Therefore, we performed RH targeting early-stage cervical cancer using the laparoendoscopic single-site (LESS) approach with an enclosed colpotomy and without a uterine manipulator [3]. DESIGN: Video demonstration of the technique. SETTING: A hospital. INTERVENTIONS: A 48-year-old postmenopausal woman received a diagnosis of stage IB1 (International Federation of Gynecology and Obstetrics, 2018) cervical cancer [4]. After being fully informed of the benefits and risks of different surgical approaches (laparotomy and MIS), she consented to the MIS. The type C RH through the LESS approach was performed successfully. The final pathologic findings confirmed stage IB1 cervical carcinoma. The patient recovered quickly, albeit with slight pain, and the incision scar was hidden perfectly for cosmetic purposes. CONCLUSION: This video demonstrates that LESS-RH with vaginal closure and without a manipulator is feasible and safe. Suspension skills played a significant role in LESS-RH. In addition, this surgical procedure involved 4 specific techniques to prevent tumor spillage: creation of a vaginal cuff, avoidance of a uterine manipulator, standard type C radical hysterectomy, and bagging of the specimen. These adaptations were meant to minimize tumor manipulation and disruption for reducing the increased risk of recurrence. However, further verifications are still required.


Assuntos
Carcinoma de Células Escamosas/cirurgia , Histerectomia/métodos , Laparoscopia/métodos , Neoplasias do Colo do Útero/cirurgia , Vagina/cirurgia , Carcinoma de Células Escamosas/patologia , Colpotomia/métodos , Feminino , Humanos , Histerectomia/instrumentação , Laparoscopia/instrumentação , Pessoa de Meia-Idade , Procedimentos Cirúrgicos Minimamente Invasivos/métodos , Estadiamento de Neoplasias , Neoplasias do Colo do Útero/patologia , Técnicas de Fechamento de Ferimentos
SELEÇÃO DE REFERÊNCIAS
Detalhe da pesquisa