Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 13 de 13
Filtrar
Más filtros












Base de datos
Intervalo de año de publicación
1.
Molecules ; 29(7)2024 Apr 03.
Artículo en Inglés | MEDLINE | ID: mdl-38611897

RESUMEN

Phenazine-based redox-active centers are capable of averting chemical bond rearrangements by coupling during the reaction process, leading to enhanced stabilization of the material. When introduced into a high-performance polymer with excellent physicochemical properties, they can be endowed with electrochemical properties and related prospective applications while maintaining the capabilities of the materials. In this study, a facile C-N coupling method was chosen for the synthesis of serial poly(aryl ether sulfone) materials containing phenazine-based redox-active centers and to explore their electrochemical properties. As expected, the cyclic voltammetry curves of PAS-DPPZ-60, which basically overlap after thousands of cycles, indicate the stability of the electrochemical properties. As an electrochromic material, the transmittance change in PAS-DPPZ-60 exhibits only a slight attenuation after as long as 600 cycles. Meanwhile, as an organic battery cathode material, PAS-DPPZ has a theoretical specific capacity of 126 mAh g-1, and the capacity retention rate is 82.6% after 100 cycles at a 0.1 C current density. The perfect combination of advantageous features between phenazine and poly(aryl ether sulfone) is considered to be the reason for the favorable electrochemical performance of the material series.

2.
Open Med (Wars) ; 18(1): 20230827, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-38025542

RESUMEN

This meta-analysis aimed to evaluate the diagnostic accuracy of touch imprint cytology (TIC) for sentinel lymph node (SLN) metastases of patients with clinical node-negative early breast cancer. The PubMed, Web of Science, Embase, and the Cochrane Library databases were meticulously searched to retrieve literature published from January 2005 to September 2022 by two independent reviewers. The meta-analysis was performed using STATA16.0, Meta-Disc 1.4, and RevMan 5.4.9. According to the inclusion criteria, 4,073 patients from 13 studies were included in this meta-analysis. The pooled sensitivity and specificity of TIC for detecting SLN metastases were 0.77 (95% CI 0.66-0.85) and 0.99 (95% CI 0.97-1.00), respectively. The pooled positive likelihood ratio and negative likelihood ratio were 76.15 (95% CI 29.16-198.84) and 0.23 (95% CI 0.15-0.36), respectively. The pooled diagnostic odds ratio was 326.82 (95% CI 132.76-804.56) and the area under the sROC curve was 0.97 (95% CI 0.95-0.98), respectively. This meta-analysis revealed that TIC with high sensitivity and specificity is a feasibility and accuracy diagnosis technique for intraoperative detection of SLN metastases in breast cancer.

3.
Biosensors (Basel) ; 13(9)2023 Sep 20.
Artículo en Inglés | MEDLINE | ID: mdl-37754130

RESUMEN

Given the advancements in modern living standards and technological development, conventional smart devices have proven inadequate in meeting the demands for a high-quality lifestyle. Therefore, a revolution is necessary to overcome this impasse and facilitate the emergence of flexible electronics. Specifically, there is a growing focus on health detection, necessitating advanced flexible preparation technology for biosensor-based smart wearable devices. Nowadays, numerous flexible products are available on the market, such as electronic devices with flexible connections, bendable LED light arrays, and flexible radio frequency electronic tags for storing information. The manufacturing process of these devices is relatively straightforward, and their integration is uncomplicated. However, their functionality remains limited. Further research is necessary for the development of more intricate applications, such as intelligent wearables and energy storage systems. Taking smart wear as an example, it is worth noting that the current mainstream products on the market primarily consist of bracelet-type health testing equipment. They exhibit limited flexibility and can only be worn on the wrist for measurement purposes, which greatly limits their application diversity. Flexible energy storage and flexible display also face the same problem, so there is still a lot of room for development in the field of flexible electronics manufacturing. In this review, we provide a brief overview of the developmental history of flexible devices, systematically summarizing representative preparation methods and typical applications, identifying challenges, proposing solutions, and offering prospects for future development.


Asunto(s)
Electrónica , Dispositivos Electrónicos Vestibles , Inteligencia , Ondas de Radio , Tecnología
4.
Math Biosci Eng ; 19(6): 5591-5609, 2022 Mar 30.
Artículo en Inglés | MEDLINE | ID: mdl-35603370

RESUMEN

This study aims to design a generalized fault diagnosis observer (GFDO) and an active fault tolerant control system (AFTCS) for external disturbances based on an aircraft control system and actuator faults. Unlike the traditional approach that assumes external disturbances are norm bounded, the Gronwall Lemma based on the external disturbances constraint condition is modelled to satisfy the system stability. Then, the GFDO is designed by two performance indices defined to simultaneously estimate system states and faults. In addition, the AFTCS is designed to obtain the desired performances in the fault case. When the fault is diagnosed by GFDO, the regular controller switches to AFTCS. Finally, an analysis of the performance of the proposed algorithm is discussed based on simulations of the F-18 aircraft control system, which illustrates the effectiveness and applicability of this method.

5.
BMC Surg ; 21(1): 378, 2021 Oct 26.
Artículo en Inglés | MEDLINE | ID: mdl-34702227

RESUMEN

BACKGROUND: It was controversial to operate on the primary site of breast cancer (BC) with bone metastasis only. We investigated the impact of surgery on BC patients with bone metastases via a SEER database retrospective analysis. METHODS: A total of 2917 BC cases with bone metastasis, first diagnosed between 2010 and 2015 in the Surveillance, Epidemiology, and Results Database (SEER) of National Cancer Institute were selected. We assessed the effect of different surgical procedures on survival and prognosis. RESULTS: Compared with the non-surgical group, the primary tumor surgical group showed longer median survival time (χ2 = 146.023, P < 0.001), and the breast-conserving subgroup showed the highest median survival time of 70 months (χ2 = 157.117, P < 0.001). Compared with the non-surgery group, the median overall survival (OS) of primary surgery group was longer (HR = 0.525, 95%CI = 0.467-0.590, P < 0.001), and the breast-conserving subgroup showed the longest median operative OS (HR = 0.394, 95%CI = 0.325-0.478, P < 0.001). CONCLUSION: This study showed that primary surgery could improve the median survival time and OS of BC patients with bone metastasis. Moreover, under the condition of low tumor burden, breast conserving surgery was a better choice.


Asunto(s)
Neoplasias Óseas , Neoplasias de la Mama , Neoplasias Óseas/epidemiología , Neoplasias Óseas/cirugía , Neoplasias de la Mama/cirugía , Femenino , Humanos , Mastectomía Segmentaria , Pronóstico , Estudios Retrospectivos , Programa de VERF
6.
Int J Gen Med ; 14: 5287-5299, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34522128

RESUMEN

BACKGROUND: Presently, no study reported the function of cathepsin H (CTSH) in thyroid carcinoma (THCA). The aim of present study was to initially explore the factors affecting CTSH expression, and association between CTSH expression and survival rate in THCA. METHODS: We explored mRNA expression of CTSH in normal and BRCA tissues, and evaluated prognostic impact of CTSH expression on the overall survival of THCA patients. Then, related factors influencing CTSH mRNA expression in THCA were analyzed. Functional enrichment analysis was performed to reveal the potential function of CTSH involved in THCA. We also constructed PPI network among co-expressed genes of CTSH to determine hub genes, followed by association analysis on hub genes with CTSH. RESULTS: (1) CTSH mRNA was highly expressed in THCA compared with normal group (P<0.001). High expression of CTSH was conducive to the overall survival of THCA patients (P=0.0027). CTSH was then determined as an independent prognostic factor in THCA (P=0.024). (2) The mRNA expression of CTSH was statistically related to patient's histological type, N stage, T stage, tumor stage and sample type (all P<0.001). CTSH copy number variation and methylation also influenced its mRNA expression (all P<0.001). (3) Pathway analysis indicated that CTSH mainly participated in cancer-related pathways, such as hedgehog signaling pathway, cytokine-cytokine receptor interaction and JAK-STAT signaling pathway (all P<0.05). (4) The top 10 co-expressed genes in whole PPI network showed significant correlation with CTSH expression (all P<0.001). CONCLUSION: CTSH higher expression was observed in THCA, which caused a good prognosis of patients. CTSH expression might be regulated by multiple factors including clinical characteristic, methylation, copy number and other genes. This study demonstrated the clinical significance of CTSH in THCA, as well as revealed the potential pathway associated with CTSH involved in thyroid cancer.

7.
ACS Appl Mater Interfaces ; 12(6): 7529-7538, 2020 Feb 12.
Artículo en Inglés | MEDLINE | ID: mdl-31957425

RESUMEN

Although high-performance donor-acceptor (D-A)-type polymers have received much attention as an important class of electrochromic (EC) materials, the related studies have mostly focused on the influence of D and A units on the band gap, onset potential, and switching time, leaving the effect of D-A structures on cycling lifetime underexplored. Herein, we design and synthesize a series of poly(aryl amino sulfone)s (PAASs) as D-A polymers with triphenylamine-based donor units and the sulfone moiety as the acceptor unit. As a result, we present new rules to design and develop D-A structure polymers with high EC cycling stability: (1) the electron-donating and -withdrawing abilities of the donor and acceptor should be balanced during the electrochemical cycle process, and this balance can be measured by the ratio of Jred/Jox; (2) the D-A structure should benefit to generate lower Eonset. By these design rules, the best-performing polymer PAAS-TPPA-OMe exhibits an excellent long-term cycling stability (over 3,900 cycles), low onset potential (0.26 V), fast switching time (6.0/4.3 s for the EC process), high contrast (87% at 688 nm and 94% at 928 nm), and high coloration efficiency (500 cm2 C-1 at 688 nm and 1131 cm2 C-1 at 928 nm).

8.
Sensors (Basel) ; 19(7)2019 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-30939807

RESUMEN

Extensive studies have shown that many animals' capability of forming spatial representations for self-localization, path planning, and navigation relies on the functionalities of place and head-direction (HD) cells in the hippocampus. Although there are numerous hippocampal modeling approaches, only a few span the wide functionalities ranging from processing raw sensory signals to planning and action generation. This paper presents a vision-based navigation system that involves generating place and HD cells through learning from visual images, building topological maps based on learned cell representations and performing navigation using hierarchical reinforcement learning. First, place and HD cells are trained from sequences of visual stimuli in an unsupervised learning fashion. A modified Slow Feature Analysis (SFA) algorithm is proposed to learn different cell types in an intentional way by restricting their learning to separate phases of the spatial exploration. Then, to extract the encoded metric information from these unsupervised learning representations, a self-organized learning algorithm is adopted to learn over the emerged cell activities and to generate topological maps that reveal the topology of the environment and information about a robot's head direction, respectively. This enables the robot to perform self-localization and orientation detection based on the generated maps. Finally, goal-directed navigation is performed using reinforcement learning in continuous state spaces which are represented by the population activities of place cells. In particular, considering that the topological map provides a natural hierarchical representation of the environment, hierarchical reinforcement learning (HRL) is used to exploit this hierarchy to accelerate learning. The HRL works on different spatial scales, where a high-level policy learns to select subgoals and a low-level policy learns over primitive actions to specialize on the selected subgoals. Experimental results demonstrate that our system is able to navigate a robot to the desired position effectively, and the HRL shows a much better learning performance than the standard RL in solving our navigation tasks.


Asunto(s)
Aprendizaje Profundo , Robótica/métodos , Aprendizaje Automático no Supervisado , Modelos Biológicos , Navegación Espacial
9.
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi ; 34(1): 99-105, 2017 Feb.
Artículo en Chino | MEDLINE | ID: mdl-29717596

RESUMEN

Attention deficit/hyperactivity disorder(ADHD) is a behavioral disorder syndrome found mainly in school-age population. At present, the diagnosis of ADHD mainly depends on the subjective methods, leading to the high rate of misdiagnosis and missed-diagnosis. To solve these problems, we proposed an algorithm for classifying ADHD objectively based on convolutional neural network. At first, preprocessing steps, including skull stripping, Gaussian kernel smoothing, et al., were applied to brain magnetic resonance imaging(MRI). Then, coarse segmentation was used for selecting the right caudate nucleus, left precuneus, and left superior frontal gyrus region. Finally, a 3 level convolutional neural network was used for classification. Experimental results showed that the proposed algorithm was capable of classifying ADHD and normal groups effectively, the classification accuracies obtained by the right caudate nucleus and the left precuneus brain regions were greater than the highest classification accuracy(62.52%) in the ADHD-200 competition, and among 3 brain regions in ADHD and the normal groups, the classification accuracy from the right caudate nucleus was the highest. It is well concluded that the method for classification of ADHD and normal groups proposed in this paper utilizing the coarse segmentation and deep learning is a useful method for the purpose. The classification accuracy of the proposed method is high, and the calculation is simple. And the method is able to extract the unobvious image features better, and can overcome the shortcomings of traditional methods of MRI brain area segmentation, which are time-consuming and highly complicate. The method provides an objective diagnosis approach for ADHD.


Asunto(s)
Trastorno por Déficit de Atención con Hiperactividad , Trastorno por Déficit de Atención con Hiperactividad/diagnóstico , Encéfalo , Núcleo Caudado , Humanos , Imagen por Resonancia Magnética/métodos , Red Nerviosa , Corteza Prefrontal
10.
Acta Biomater ; 10(8): 3686-95, 2014 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-24879311

RESUMEN

The present work reports the construction of a drug delivery nanovehicle via a pH-sensitive assembly strategy for improved cellular internalization and intracellular drug liberation. Through spontaneous formation of boronate linkage in physiological conditions, phenylboronic acid-modified cholesterol was able to attach onto catechol-pending methoxypoly(ethylene glycol)-block-poly(l-lysine). This comb-type polymer can self-organize into a micellar nanoconstruction that is able to effectively encapsulate poorly water-soluble agents. The blank micelles exhibited negligible in vitro cytotoxicity, yet doxorubicin (DOX)-loaded micelles could effectively induce cell death at a level comparable to free DOX. Owing to the acid-labile feature of the boronate linkage, a reduction in environmental pH from pH 7.4 to 5.0 could trigger the dissociation of the nanoconstruction, which in turn could accelerate the liberation of entrapped drugs. Importantly, the blockage of endosomal acidification in HeLa cells by NH4Cl treatment significantly decreased the nuclear uptake efficiency and cell-killing effect mediated by the DOX-loaded nanoassembly, suggesting that acid-triggered destruction of the nanoconstruction is of significant importance in enhanced drug efficacy. Moreover, confocal fluorescence microscopy and flow cytometry assay revealed the effective internalization of the nanoassemblies, and their cellular uptake exhibited a cholesterol dose-dependent profile, indicating the contribution of introduced cholesterol functionality to the transmembrane process of the nanoassembly.


Asunto(s)
Núcleo Celular/metabolismo , Colesterol/química , Doxorrubicina/farmacocinética , Nanocápsulas/química , Polietilenglicoles/química , Polilisina/química , Ácidos Borónicos/química , Catecoles/química , Reactivos de Enlaces Cruzados/química , Preparaciones de Acción Retardada/síntesis química , Doxorrubicina/administración & dosificación , Doxorrubicina/química , Ésteres , Células HeLa , Humanos , Concentración de Iones de Hidrógeno , Nanocápsulas/ultraestructura , Tamaño de la Partícula , Vehículos Farmacéuticos/síntesis química
11.
Tob Control ; 22 Suppl 2: ii16-20, 2013 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-23708268

RESUMEN

OBJECTIVES: To examine contextual and individual demographical predictors of smoking and exposure to second-hand smoke (SHS) in a tobacco-cultivating rural area of southwest China. METHODS: A cross-sectional survey of 4070 consenting individuals aged 18 years or more was conducted in 2010. Information on demographical characteristics, tobacco smoking status and SHS exposure were obtained by a standard questionnaire. Multilevel logistic regression was used to model the variation in prevalence of smoking and SHS exposure. RESULTS: In the study population, the prevalence rates of smoking and exposure to SHS were 63.5% and 74.7% for men, and 0.6% and 71.2% for women, respectively. Men were more likely to use tobacco than women: OR 8.27, 95% CI (4.83 to 10.97). Age was inversely associated with the probability of tobacco use (OR 0.98, 95% CI 0.97 to 0.99), and exposure to SHS (OR 0.97, 95% CI 0.96 to 0.99). Individual educational level was inversely associated with smoking, but showed no association with exposure to SHS. Adults who did not grow tobacco were less likely to consume tobacco (OR 0.75, 95% CI 0.57 to 0.99) and to be exposed to SHS (OR 0.76, 95% CI 0.58 to 0.99). Living in a high-income community was associated with a low rate of current smoking (OR 0.66, 95% CI 0.57 to 0.77) and SHS exposure (OR 0.58, 95% CI 0.52 to 0.65). CONCLUSIONS: Future interventions to reduce smoking and exposure to SHS in China should focus more on tobacco farmers, less-educated individuals and on poor rural communities.


Asunto(s)
Agricultura/estadística & datos numéricos , Población Rural/estadística & datos numéricos , Fumar/epidemiología , Contaminación por Humo de Tabaco/estadística & datos numéricos , Adolescente , Adulto , Factores de Edad , Anciano , China/epidemiología , Estudios Transversales , Escolaridad , Femenino , Humanos , Modelos Logísticos , Masculino , Persona de Mediana Edad , Prevalencia , Factores Sexuales , Factores Socioeconómicos , Encuestas y Cuestionarios , Nicotiana , Adulto Joven
12.
BMC Public Health ; 12(1): 842, 2012 Oct 04.
Artículo en Inglés | MEDLINE | ID: mdl-23035644

RESUMEN

BACKGROUND: This study describes the patterns and socioeconomic influences of tobacco use among adults in tobacco-cultivating regions of rural southwest China. METHODS: A cross-sectional survey was conducted in 8681 adults aged ≥18 years in rural areas of Yunnan Province, China from 2010 to 2011. A standardized questionnaire was administered to obtain data about participants' demographic characteristics, individual socioeconomic status, ethnicity, self-reported smoking habits, and exposure to secondhand smoke (SHS). The socioeconomic predictors of current smoking, nicotine addiction, and SHS exposure were analyzed using multivariate logistic regression. RESULTS: The prevalence rates of tobacco use were much higher in men compared with women (current smoking 68.5% vs. 1.3%; and nicotine dependence 85.2% vs. 72.7%). However, the rate of SHS exposure was higher in women compared with men (76.6% vs. 70.5%). Tobacco farmers had higher prevalence rates of current smoking, nicotine dependence, and SHS exposure compared with participants not engaged in tobacco farming (P<0.01). Most tobacco users (84.5%) reported initiating smoking during adolescence. A total of 81.1% of smokers smoked in public places, and 77.6% smoked in workplaces. Individuals belonging to an ethnic minority had a lower probability of SHS exposure and nicotine dependence. Individual educational level was found to be inversely associated with the prevalence of current smoking, exposure to SHS, and nicotine dependence. Higher annual household income was associated with a greater risk of nicotine dependence. CONCLUSIONS: This study suggests that tobacco control efforts in rural southwest China must be tailored to address tobacco-cultivating status and socioeconomic factors.


Asunto(s)
Exposición a Riesgos Ambientales/estadística & datos numéricos , Población Rural/estadística & datos numéricos , Fumar/epidemiología , Industria del Tabaco , Contaminación por Humo de Tabaco/estadística & datos numéricos , Adolescente , Adulto , Anciano , China/epidemiología , Estudios Transversales , Femenino , Humanos , Masculino , Persona de Mediana Edad , Factores de Riesgo , Distribución por Sexo , Factores Socioeconómicos , Adulto Joven
13.
J Adolesc Health ; 51(3): 279-84, 2012 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-22921139

RESUMEN

PURPOSE: To provide clinically meaningful, normative reference data that describe pubertal timing indicators among urban and rural Chinese girls. METHODS: Girls of Chinese Han ethnicity from grade 1 in elementary schools through grade 12 in junior high schools in eight regions participated in China Puberty Research Collaboration from October 2010 to May 2011. At examination, stages of breast and pubic hair development were assessed by trained physicians. Data on menses were collected through questionnaire survey. RESULTS: A total of 15,388 girls aged 6.0-18.9 years participated in this collaboration study. Among them, approximately 53.5% (8,238) came from rural areas. The median ages at stage 2 of breast development of Chinese girls were 9.18 (95% confidence interval: 8.91-9.44) years and at stage 2 for pubic hair growth were 11.65 (95% confidence interval: 11.41-11.90) years. Girls with body mass index ≥85th percentile had earlier age for B2 (Tanner stage 2 for breast development), B3 (Tanner stage 3 for breast development), PH2 (Tanner stage 2 for pubic hair development), PH3 (Tanner stage 3 for pubic hair development), and menarche compared with girls with body mass index < 85th percentile. Urban girls achieved PH2, PH3, and menarche at a much earlier age than rural girls, except for B2 and B3 attainment. Mean menarcheal age is 12.43 years. CONCLUSIONS: This study presented up-to-date data on female pubertal timing in a national sample of Chinese Han ethnicity girls and separately for urban and rural areas.


Asunto(s)
Pubertad , Población Rural/estadística & datos numéricos , Población Urbana/estadística & datos numéricos , Adolescente , Índice de Masa Corporal , Mama/crecimiento & desarrollo , Niño , China/epidemiología , Femenino , Humanos , Menarquia , Valores de Referencia , Encuestas y Cuestionarios
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...