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1.
Molecules ; 29(15)2024 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-39125046

RESUMO

Supercapacitors (SCs) are widely recognized as competitive power sources for energy storage. The hierarchical structure of nickel vanadium sulfide nanoparticles encapsulated on graphene nanosheets (NVS/G) was fabricated using a cost-effective and scalable solvothermal process. The reaction contents of the composites were explored and optimized. TEM images displayed the nickel vanadium sulfide nanoparticles (NVS NPs) with 20-30 nm average size anchored to graphene nanosheets. The interconnection of graphene nanosheets encapsulating NVS nanoparticles effectively reduces the ion diffusion path between the electrode and electrolyte, thereby enhancing electrochemical performance. The NVS/G composite demonstrated improved electrochemical performance, achieving a maximum of 1437 F g-1 specific capacitance at 1 A g-1, remarkable rate capability retaining of 1050 F g-1 at 20 A g-1, and exceptional cycle stability with 91.2% capacitance retention following 10,000 cycles. The NVS/G composite was employed as a cathode, and reduced graphene oxide (rGO) was used as an anode material to assemble a device. Importantly, asymmetric SCs using NVS/G//rGO achieved 74.7 W h kg-1 energy density at 0.8 kW kg-1 power density, along with outstanding stability with 88.2% capacitance retention following 10,000 cycles. These superior properties of the NVS/G electrode highlight its significant potential in energy storage applications.

2.
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi ; 41(2): 272-280, 2024 Apr 25.
Artigo em Zh | MEDLINE | ID: mdl-38686407

RESUMO

The existing one-time identity authentication technology cannot continuously guarantee the legitimacy of user identity during the whole human-computer interaction session, and often requires active cooperation of users, which seriously limits the availability. This study proposes a new non-contact identity recognition technology based on cardiac micro-motion detection using ultra wideband (UWB) bio-radar. After the multi-point micro-motion echoes in the range dimension of the human heart surface area were continuously detected by ultra wideband bio-radar, the two-dimensional principal component analysis (2D-PCA) was exploited to extract the compressed features of the two-dimensional image matrix, namely the distance channel-heart beat sampling point (DC-HBP) matrix, in each accurate segmented heart beat cycle for identity recognition. In the practical measurement experiment, based on the proposed multi-range-bin & 2D-PCA feature scheme along with two conventional reference feature schemes, three typical classifiers were selected as representatives to conduct the heart beat identification under two states of normal breathing and breath holding. The results showed that the multi-range-bin & 2D-PCA feature scheme proposed in this paper showed the best recognition effect. Compared with the optimal range-bin & overall heart beat feature scheme, our proposed scheme held an overall average recognition accuracy of 6.16% higher (normal respiration: 6.84%; breath holding: 5.48%). Compared with the multi-distance unit & whole heart beat feature scheme, the overall average accuracy increase was 27.42% (normal respiration: 28.63%; breath holding: 26.21%) for our proposed scheme. This study is expected to provide a new method of undisturbed, all-weather, non-contact and continuous identification for authentication.


Assuntos
Coração , Análise de Componente Principal , Humanos , Coração/fisiologia , Algoritmos , Frequência Cardíaca , Processamento de Sinais Assistido por Computador , Movimento (Física) , Identificação Biométrica/métodos , Respiração
3.
World J Surg Oncol ; 21(1): 28, 2023 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-36721235

RESUMO

BACKGROUND AND OBJECTIVES: In patients with colorectal cancer and clinically suspected para-aortic lymph node metastasis, the survival benefit of para-aortic lymphadenectomy is unknown. We conducted a meta-analysis and systematic review to investigate it. METHODS: PubMed, Web of Science, and EMBASE were searched until January 2000 to April 2022 to identify studies reporting overall survivals, complication rates, and hazard ratios of prognostic factors in patients with colorectal cancer undergoing para-aortic lymphadenectomy, and those data were pooled. RESULTS: Twenty retrospective studies (1021 patients undergoing para-aortic lymphadenectomy) met the inclusion criteria. Meta-analysis indicates that participants undergoing para-aortic lymphadenectomy were associated with 5-year survival benefit, compared to those not receiving para-aortic lymphadenectomy (odds ratio = 3.73, 95% confidence interval: 2.05-6.78), but there was no significant difference in complication rate (odds ratio = 0.97, 95% confidence interval: 0.46-2.08). Further analysis of para-aortic lymphadenectomy group showed that 5-year survival of the positive group with pathologically para-aortic lymph node metastasis was lower than that of the negative group (odds ratio = 0.19, 95% confidence interval: 0.11-0.31). Moreover, complete resection (odds ratio = 5.26, 95% confidence interval: 2.02-13.69), para-aortic lymph node metastasis (≤4) (hazard ratio = 1.88, 95% confidence interval: 0.97-3.62), and medium-high differentiation (hazard ratio = 2.98, 95% confidence interval: 1.48-5.99) were protective factors for survival. Preoperative extra-retroperitoneal metastasis was associated with poorer relapse-free survival (hazard ratio = 1.85, 95% confidence interval: 1.10-3.10). CONCLUSION: Para-aortic lymphadenectomy had promising clinical efficacy in prolonging survival rather than complication rate in patients with colorectal cancer and clinically diagnostic para-aortic lymph node metastasis. Further prospective studies should be performed. TRIAL REGISTRATION: PROSPERO: CRD42022379276.


Assuntos
Neoplasias Colorretais , Excisão de Linfonodo , Humanos , Neoplasias Colorretais/cirurgia , Metástase Linfática , Estudos Prospectivos , Estudos Retrospectivos
4.
J Clin Pharm Ther ; 47(12): 1994-2007, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-35894086

RESUMO

WHAT IS KNOWN AND OBJECTIVES: Potential inappropriate medications (PIMs) can increase the risk of medication-induced harm. However, there are no studies regarding PIMs in older and critically ill patients with cardiovascular diseases in China. Therefore, studies evaluating PIMs in these patients can help in the implementation of more effective interventions to reduce the risk of drug use. Our objective was to analyse the prevalence of PIMs in elderly patients admitted to the cardiac intensive care unit (CICU) comparing the 2019 Beers criteria (Beers criteria), Screening Tool of Older People's Potentially Inappropriate Prescriptions (STOPP) criteria version 2 (STOPP criteria) and criteria of potentially inappropriate medications for older adults in China (Chinese criteria); and analyse the factors influencing the PIMs. METHODS: This cross-sectional and retrospective study was performed with elderly patients (≥65 years) admitted to the CICU of the Beijing Tongren Hospital in China from January 2019 to June 2020. The PIMs were identified based on the Chinese, STOPP and Beers criteria at admission and discharge. The three criteria were compared using the Kappa statistic. Multiple regression analysis was used to investigate the influencing factors associated with PIMs. RESULTS AND DISCUSSION: A total of 369 patients who met the inclusion/exclusion criteria were included in this study. According to the three criteria used to evaluate the PIMs, the prevalence was 78.3% and 72.6% at admission and discharge, respectively. The prevalence rate of PIMs determined by the Chinese criteria was 62.1% at admission versus 56.6% at discharge (p = 0.134); the Beers criteria was 53.9% at admission versus 46.9% at discharge (p = 0.056); by the STOPP criteria was 20.6% at admission versus 13.8% at discharge (p = 0.015). Moreover, 28.9% (STOPP criteria), 56.8% (Beers criteria) and 73.4% (Chinese criteria) of patients taking PIMs on admission still had the same problem at discharge. The most common PIMs screened by the Beers, STOPP and Chinese criteria were diuretics, benzodiazepines and clopidogrel, respectively. Besides, the three criteria showed poor agreement. Finally, the stronger predictor of PIMs was the increased number of medications (p < 0.05). WHAT IS NEW AND CONCLUSION: The prevalence of PIMs in elderly patients admitted to the CICU was high. The Chinese, STOPP and Beers criteria are effective screening tools to detect PIMs, but the consistency between them was poor. The increased number of medications was a significant predictor of PIMs.


Assuntos
População do Leste Asiático , Lista de Medicamentos Potencialmente Inapropriados , Humanos , Idoso , Estudos Retrospectivos , Estudos Transversais , Prescrição Inadequada , Unidades de Terapia Intensiva
5.
Proc Natl Acad Sci U S A ; 116(33): 16621-16630, 2019 08 13.
Artigo em Inglês | MEDLINE | ID: mdl-31346081

RESUMO

Implantation of the blastocyst into the uterus is the gateway for further embryonic development in mammals. Programming of blastocyst to an implantation-competent state known as blastocyst activation is the determining factor for implantation into the receptive uterus. However, it remains largely unclear how the blastocyst is globally programmed for implantation. Employing a delayed implantation mouse model, we show here that the blastocyst undergoes extensive programming essential for implantation. By analyzing the transcriptional profile of blastocysts with different implantation competency, we reveal the dynamic change in the biosynthesis, metabolism, and proliferation during blastocyst reactivation from diapause. We also demonstrate that reactivation of the X chromosome, one of the most important events during periimplantation of female embryonic development, is not completed even in blastocysts under conditions of dormancy, despite long term suspension in the uterus. Moreover, the mural trophectoderm (TE), but not the polar TE, differentiates to be more invasive through the weakened cell-cell tight junctions and extracellular matrices (ECMs). By analyzing the differentially expressed profile of secretory proteins, we further demonstrate that the blastocyst functions as a proinflammatory body to secrete proinflammatory signals, such as TNFα and S100A9, thereby triggering embryo-uterine attachment reaction during implantation. Collectively, our data systematically and comprehensively disclose the programming of blastocyst reactivation from diapause for implantation and uncover previously undefined roles of blastocyst during implantation.


Assuntos
Blastocisto/metabolismo , Implantação do Embrião/genética , Transcriptoma/genética , Cromossomo X/genética , Animais , Blastocisto/citologia , Calgranulina B/genética , Calgranulina B/metabolismo , Proliferação de Células/genética , Ectoderma/metabolismo , Ectoderma/ultraestrutura , Endométrio/patologia , Feminino , Regulação da Expressão Gênica no Desenvolvimento , Inflamação/patologia , Camundongos , Fatores de Tempo , Fator de Necrose Tumoral alfa/metabolismo , Regulação para Cima/genética
6.
Ecotoxicol Environ Saf ; 202: 110859, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32574861

RESUMO

The effects of quinoid compounds on azo dyes decolorization were studied. Compared with other quinones, menadione was the most effective at aiding azo dye decolorization. Sodium formate was a suitable carbon source for the anaerobic decolorization system. Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) analysis indicated that the microbial structure changed in response to varying carbon sources. Phylogenetic analysis showed that the anaerobic sludge was consisted mainly of nine genera. The mechanism studies showed that the biotransformation of menadione to its hydroquinone form was the rate-limiting step in the dye decolorization process. Moreover, study of the electron transfer mechanism of quinone-mediated reduction showed that azo dye decolorization is not a specific reaction. The NADH chain was involved in the decolorization process. The methane production test indicated that azo dyes had an inhibitory effect on methane production. However, supplementation with a redox mediator could recover the inhibited methanogenesis. High-throughput sequencing analysis revealed that the methanogenic archaeal community was altered in the anaerobic sludge with or without azo dyes and the redox mediator.


Assuntos
Compostos Azo/metabolismo , Quinonas/metabolismo , Eliminação de Resíduos Líquidos , Anaerobiose , Compostos Azo/química , Benzoquinonas , Biotransformação , Catálise , Corantes/química , Metano/metabolismo , Oxirredução , Filogenia , Quinonas/química , Esgotos
7.
Sensors (Basel) ; 18(11)2018 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-30423841

RESUMO

Human being detection via ultra-wideband (UWB) radars has shown great prospects in many areas, such as biomedicine, military operation, public security, emergency rescue, and so on. When a person stays stationary, the main feature that separates him/her from surroundings is the movement of chest wall due to breath. There have been many algorithms developed for breath detection while using UWB radars. However, those algorithms were almost based on a basic scheme that focused on processing in the time dimension of UWB data. They did not utilize the benefits from the wide operational bandwidth of UWB radars to show potential superiority over those narrowband systems such as a continuous wave (CW) Doppler radar. In this paper, a breath detection method was proposed based on operational bandwidth segmentation. A basic theoretical model was firstly introduced, indicating that characteristics of breath signals contained in UWB echoes were consistent among the operational frequencies, while those of clutters were not. So, the method divided a set of UWB echo data into a number of subsets, each of which corresponded to a sub-band within the operational bandwidth of the UWB radar. Thus information about the operational frequency is provided for subsequent processing. With the aid of the information, a breath enhancement algorithm was developed mainly by averaging the segmented UWB data along the operational frequency. The algorithm's performance was verified by data measured by a stepped-frequency CW (SFCW) UWB radar. The experimental results showed that the algorithm performed better than that without the segmentation. They also showed its feasibility for fast detection of breath based on a short duration of data. Moreover, the method's potential for target identification and impulse-radio (IR) UWB radar was investigated. In summary, the method provides a new processing scheme for UWB radars when they are used for breath detection. With this scheme, the UWB radars have a benefit of greater flexibility in data processing over those narrowband radars, and thus will perform more effectively and efficiently in practical applications.

8.
Exp Mol Pathol ; 102(1): 59-64, 2017 02.
Artigo em Inglês | MEDLINE | ID: mdl-28062212

RESUMO

Head and neck squamous cell carcinoma (HNSCC) is one of the most common cancers in the world. CD147, a transmembrane glycoprotein, has been reported to be correlated with cancer progression, metastasis, and chemoresistance in various cancers. In this study, we aimed to investigate the mechanism of CD147 in regulating drug resistance in HNSCC cells. qRT-PCR were used to evaluated the expression of CD147 in 57 HNSCC tumorous tissues and 2 cell lines. Increased expression of CD147 was found in most HNSCC samples, and the expression level of CD147 was correlated with multidrug resistance. CD147 RNA silencing decreased the chemoresistance of HNSCC cells by deactivating MAPK/ERK signaling pathway. Further investigation revealed that either rescue expression of CD147 or treatment of MAPK/ERK activator phorbol 12-myristate 13-acetate (PMA) in CD147 knockdown CRC cell line attenuated the decreased chemoresistance in CD147 knockdown cells. Taken together, our results suggest that CD147 promotes chemoresistance by activating MAPK/ERK signaling pathway in HNSCC.


Assuntos
Basigina/genética , Carcinoma de Células Escamosas/genética , Resistencia a Medicamentos Antineoplásicos/genética , Neoplasias de Cabeça e Pescoço/genética , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Interferência de RNA , Antineoplásicos/farmacologia , Basigina/metabolismo , Western Blotting , Carcinoma de Células Escamosas/metabolismo , Carcinoma de Células Escamosas/patologia , Linhagem Celular , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/genética , Relação Dose-Resposta a Droga , Resistência a Múltiplos Medicamentos/genética , Regulação Neoplásica da Expressão Gênica , Células HEK293 , Neoplasias de Cabeça e Pescoço/metabolismo , Neoplasias de Cabeça e Pescoço/patologia , Humanos , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Reação em Cadeia da Polimerase Via Transcriptase Reversa
9.
Sensors (Basel) ; 17(3)2017 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-28282892

RESUMO

The detection of the vibration signal from human vocal folds provides essential information for studying human phonation and diagnosing voice disorders. Doppler radar technology has enabled the noncontact measurement of the human-vocal-fold vibration. However, existing systems must be placed in close proximity to the human throat and detailed information may be lost because of the low operating frequency. In this paper, a long-distance detection method, involving the use of a 94-GHz millimeter-wave radar sensor, is proposed for detecting the vibration signals from human vocal folds. An algorithm that combines empirical mode decomposition (EMD) and the auto-correlation function (ACF) method is proposed for detecting the signal. First, the EMD method is employed to suppress the noise of the radar-detected signal. Further, the ratio of the energy and entropy is used to detect voice activity in the radar-detected signal, following which, a short-time ACF is employed to extract the vibration signal of the human vocal folds from the processed signal. For validating the method and assessing the performance of the radar system, a vibration measurement sensor and microphone system are additionally employed for comparison. The experimental results obtained from the spectrograms, the vibration frequency of the vocal folds, and coherence analysis demonstrate that the proposed method can effectively detect the vibration of human vocal folds from a long detection distance.


Assuntos
Prega Vocal , Humanos , Fonação , Radar , Vibração , Voz
10.
Sensors (Basel) ; 17(10)2017 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-28973988

RESUMO

Ultra-wide band (UWB) radar for short-range human target detection is widely used to find and locate survivors in some rescue missions after a disaster. The results of the application of bistatic UWB radar for detecting multi-stationary human targets have shown that human targets close to the radar antennas are very often visible, while those farther from radar antennas are detected with less reliability. In this paper, on account of the significant difference of frequency content between the echo signal of the human target and that of noise in the shadowing region, an algorithm based on wavelet entropy is proposed to detect multiple targets. Our findings indicate that the entropy value of human targets was much lower than that of noise. Compared with the method of adaptive filtering and the energy spectrum, wavelet entropy can accurately detect the person farther from the radar antennas, and it can be employed as a useful tool in detecting multiple targets by bistatic UWB radar.

11.
Biochem Biophys Res Commun ; 469(4): 836-41, 2016 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-26686420

RESUMO

The morphology and function of Leydig cells are changed during the development, mature and senility of Leydig cells along the life span of males. This study was to observe the growth morphology of adult mouse Leydig cells in culture, aiming to provide a reference for furthermore understanding of the biological function of Leydig cells by in vitro model. Testes of two-month-old mice were decapsulated and then the Leydig cells were isolated by collagenase digestion and were cultured in DMEM/F12 supplemented with 10% FBS. The Leydig cells were identified by HSD3B staining and RT-PCR. After 48-h Leydig cell culture, both the nucleus and the cytoplasm were very clear under the optical microscope. The nucleus was big and round and the cytoplasm was filled with abundant lipid drops with a strong refractivity. After 5-day culture, Leydig cells were fully elongated in spindle, triangular, polygonal, oval or irregular shapes. Some cells grew in aggregation, and some cells grew independently. Leydig cells in aggregation elongated many cellular tentacles for intercellular connections, which formed an epithelium-like appearance. After HSD3B staining, the individual Leydig cells were stained with different extents, demonstrated that the heterogeneity of HSD3B activity in individual Leydig cells in primary culture. RT-PCR results showed that Leydig cells in culture after 5 days could express Leydig cell-specific transcriptions, HSD3B6, CYP17A1 and StAR. These results showed the morphological characterization of adult mouse Leydig cells in culture, which will lay a foundation to elucidate the relationship between the morphology and function of Leydig cells.


Assuntos
Células Intersticiais do Testículo/classificação , Células Intersticiais do Testículo/citologia , Testículo/citologia , Animais , Tamanho Celular , Células Cultivadas , Masculino , Camundongos , Camundongos Endogâmicos ICR
12.
Nat Methods ; 10(10): 981-4, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23955771

RESUMO

Poly(ADP-ribosyl)ation is catalyzed by a family of enzymes known as PARPs. We describe a method to characterize the human aspartic acid- and glutamic acid-ADP-ribosylated proteome. We identified 1,048 ADP-ribosylation sites on 340 proteins involved in a wide array of nuclear functions; among these were many previously unknown PARP downstream targets whose ADP-ribosylation was sensitive to PARP inhibitor treatment. We also confirmed that iniparib had a negligible effect on PARP activity in intact cells.


Assuntos
Adenosina Difosfato Ribose/química , Ácido Aspártico/química , Ácido Glutâmico/química , Poli(ADP-Ribose) Polimerases/química , Proteoma/química , Adenosina Difosfato Ribose/genética , Adenosina Difosfato Ribose/metabolismo , Ácido Aspártico/metabolismo , Sítios de Ligação , Dano ao DNA , Técnicas de Silenciamento de Genes , Ácido Glutâmico/metabolismo , Glicosídeo Hidrolases/química , Glicosídeo Hidrolases/genética , Glicosídeo Hidrolases/metabolismo , Células HCT116 , Humanos , Peróxido de Hidrogênio/farmacologia , Modelos Moleculares , Poli(ADP-Ribose) Polimerase-1 , Inibidores de Poli(ADP-Ribose) Polimerases , Poli(ADP-Ribose) Polimerases/genética , Poli(ADP-Ribose) Polimerases/metabolismo , Conformação Proteica , Processamento de Proteína Pós-Traducional , Proteoma/genética , Proteoma/metabolismo
13.
Biol Reprod ; 94(1): 24, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26674564

RESUMO

The process of germline development carries genetic information and preparatory totipotency across generations. The last decade has witnessed remarkable successes in the generation of germline cells from mouse pluripotent stem cells, especially induced germline cells with the capacity for producing viable offspring, suggesting clinical applications of induced germline cells in humans. However, to date, the culture systems for germline induction with accurate sex-specific meiosis and epigenetic reprogramming have not been well-established. In this study, we primarily focus on the mouse model to discuss key signaling events for germline induction. We review mechanisms of competent regulators on primordial germ cell induction and discuss current achievements and difficulties in inducing sex-specific germline development. Furthermore, we review the developmental identities of mouse embryonic stem cells and epiblast stem cells under certain defined culture conditions as it relates to the differentiation process of becoming germline cells.


Assuntos
Células Germinativas/fisiologia , Células-Tronco Pluripotentes/fisiologia , Transdução de Sinais/fisiologia , Animais , Células-Tronco Embrionárias , Feminino , Masculino , Camundongos , Gravidez , Processos de Determinação Sexual
14.
Langmuir ; 32(46): 12129-12136, 2016 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-27794620

RESUMO

In this work, we applied total internal reflection microscopy (TIRM) to directly measure the interactions between three different kinds of macroscopic surfaces: namely bare polystyrene (PS) particle and bare silica surface (bare-PS/bare-silica), PS particle and silica surfaces both coated with bovine serum albumin (BSA) (BSA-PS/BSA-silica), and PS particle and silica surfaces both modified with polyethylene glycol (PEG) (PEG-PS/PEG-silica) polymers, in phosphate buffer solution (PBS) and fetal bovine serum (FBS). Our results showed that in PBS, all the bare-PS, BSA-PS, and PEG-PS particles were irreversibly deposited onto the bare silica surface or surfaces coated either with BSA or PEG. However, in FBS, the interaction potentials between the particle and surface exhibited both free-diffusing particle and stuck particle profiles. Dynamic light scattering (DLS) and elliposmeter measurements indicated that there was a layer of serum proteins adsorbed on the PS particle and silica surface. TIRM measurement revealed that such adsorbed serum proteins can mediate the surface-surface interactions by providing additional stabilization under certain conditions, but also promoting bridging effect between the two surfaces. The measured potential profile of the stuck particle in FBS thus was much wider than in PBS. These quantitative measurements provide insights that serum proteins adsorbed onto surfaces can regulate surface-surface interactions, thus leading to unique moving behavior and stability of colloidal particles in the serum environment.


Assuntos
Poliestirenos/química , Soroalbumina Bovina/química , Dióxido de Silício/química , Adsorção , Polietilenoglicóis , Polímeros , Propriedades de Superfície
15.
Sensors (Basel) ; 16(6)2016 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-27314362

RESUMO

The through-wall detection and classification of human activities are critical for anti-terrorism, security, and disaster rescue operations. An effective through-wall detection and classification technology is proposed for finer-grained human activities such as piaffe, picking up an object, waving, jumping, standing with random micro-shakes, and breathing while sitting. A stepped-frequency continuous wave (SFCW) bio-radar sensor is first used to conduct through-wall detection of finer-grained human activities; Then, a comprehensive range accumulation time-frequency transform (CRATFR) based on inverse weight coefficients is proposed, which aims to strengthen the micro-Doppler features of finer activity signals. Finally, in combination with the effective eigenvalues extracted from the CRATFR spectrum, an optimal self-adaption support vector machine (OS-SVM) based on prior human position information is introduced to classify different finer-grained activities. At a fixed position (3 m) behind a wall, the classification accuracies of six activities performed by eight individuals were 98.78% and 93.23%, respectively, for the two scenarios defined in this paper. In the position-changing experiment, an average classification accuracy of 86.67% was obtained for five finer-grained activities (excluding breathing) of eight individuals within 6 m behind the wall for the most practical scenario, a significant improvement over the 79% accuracy of the current method.

16.
Sensors (Basel) ; 16(11)2016 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-27854356

RESUMO

Remarkable progress has been achieved in the detection of single stationary human. However, restricted by the mutual interference of multiple humans (e.g., strong sidelobes of the torsos and the shadow effect), detection and localization of the multiple stationary humans remains a huge challenge. In this paper, ultra-wideband (UWB) multiple-input and multiple-output (MIMO) radar is exploited to improve the detection performance of multiple stationary humans for its multiple sight angles and high-resolution two-dimensional imaging capacity. A signal model of the vital sign considering both bi-static angles and attitude angle of the human body is firstly developed, and then a novel detection method is proposed to detect and localize multiple stationary humans. In this method, preprocessing is firstly implemented to improve the signal-to-noise ratio (SNR) of the vital signs, and then a vital-sign-enhanced imaging algorithm is presented to suppress the environmental clutters and mutual affection of multiple humans. Finally, an automatic detection algorithm including constant false alarm rate (CFAR), morphological filtering and clustering is implemented to improve the detection performance of weak human targets affected by heavy clutters and shadow effect. The simulation and experimental results show that the proposed method can get a high-quality image of multiple humans and we can use it to discriminate and localize multiple adjacent human targets behind brick walls.


Assuntos
Radar , Algoritmos , Humanos , Razão Sinal-Ruído , Sinais Vitais/fisiologia
17.
Sensors (Basel) ; 16(11)2016 Oct 27.
Artigo em Inglês | MEDLINE | ID: mdl-27801795

RESUMO

Ultra-wideband (UWB) radar has been widely used for detecting human physiological signals (respiration, movement, etc.) in the fields of rescue, security, and medicine owing to its high penetrability and range resolution. In these applications, especially in rescue after disaster (earthquake, collapse, mine accident, etc.), the presence, number, and location of the trapped victims to be detected and rescued are the key issues of concern. Ample research has been done on the first issue, whereas the identification and localization of multi-targets remains a challenge. False positive and negative identification results are two common problems associated with the detection of multiple stationary human targets. This is mainly because the energy of the signal reflected from the target close to the receiving antenna is considerably stronger than those of the targets at further range, often leading to missing or false recognition if the identification method is based on the energy of the respiratory signal. Therefore, a novel method based on cross-correlation is proposed in this paper that is based on the relativity and periodicity of the signals, rather than on the energy. The validity of this method is confirmed through experiments using different scenarios; the results indicate a discernible improvement in the detection precision and identification of the multiple stationary targets.


Assuntos
Movimento/fisiologia , Radar , Respiração , Algoritmos , Humanos , Radar/instrumentação , Processamento de Sinais Assistido por Computador , Termodinâmica
18.
Sensors (Basel) ; 15(7): 14830-44, 2015 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-26115454

RESUMO

After chemical or nuclear leakage or explosions, finding survivors is a huge challenge. Although human bodies can be found by smart vehicles and drones equipped with cameras, it is difficult to verify if the person is alive or dead this way. This paper describes a continuous wave radar sensor for remotely sensing the vital signs of human subjects. Firstly, a compact and portable 24 GHz Doppler radar system is designed to conduct non-contact detection of respiration signal. Secondly, in order to improve the quality of the respiration signals, the self-correlation and adaptive line enhancer (ALE) methods are proposed to minimize the interferences of any moving objects around the human subject. Finally, the detection capabilities of the radar system and the signal processing method are verified through experiments which show that human respiration signals can be extracted when the subject is 7 m away outdoors. The method provided in this paper will be a promising way to search for human subjects outdoors.


Assuntos
Monitorização Fisiológica/instrumentação , Monitorização Fisiológica/métodos , Respiração , Processamento de Sinais Assistido por Computador/instrumentação , Algoritmos , Emergências , Humanos , Radar , Sobreviventes
19.
Sensors (Basel) ; 16(1)2015 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-26729126

RESUMO

In order to improve the speech acquisition ability of a non-contact method, a 94 GHz millimeter wave (MMW) radar sensor was employed to detect speech signals. This novel non-contact speech acquisition method was shown to have high directional sensitivity, and to be immune to strong acoustical disturbance. However, MMW radar speech is often degraded by combined sources of noise, which mainly include harmonic, electrical circuit and channel noise. In this paper, an algorithm combining empirical mode decomposition (EMD) and mutual information entropy (MIE) was proposed for enhancing the perceptibility and intelligibility of radar speech. Firstly, the radar speech signal was adaptively decomposed into oscillatory components called intrinsic mode functions (IMFs) by EMD. Secondly, MIE was used to determine the number of reconstructive components, and then an adaptive threshold was employed to remove the noise from the radar speech. The experimental results show that human speech can be effectively acquired by a 94 GHz MMW radar sensor when the detection distance is 20 m. Moreover, the noise of the radar speech is greatly suppressed and the speech sounds become more pleasant to human listeners after being enhanced by the proposed algorithm, suggesting that this novel speech acquisition and enhancement method will provide a promising alternative for various applications associated with speech detection.


Assuntos
Algoritmos , Processamento de Sinais Assistido por Computador , Fala/classificação , Adulto , Feminino , Humanos , Masculino , Espectrografia do Som , Adulto Jovem
20.
Zhongguo Yi Liao Qi Xie Za Zhi ; 39(4): 244-8, 2015 Jul.
Artigo em Zh | MEDLINE | ID: mdl-26665941

RESUMO

Physiological monitoring devices in modern clinical area are basically used electrodes or sensors directly touching the surface of human subject body, which will increase physiological and psychological load of the subjects. In order to realize non-contact monitoring of respiration and heartbeat, firstly, the micro bioradar was used to detect human body motion signal. Then, the respiration signal and heartbeat signal was extracted from the body-motion signal by using signal and conditioning circuits, digital filter and signal processing. Finally, the results of heart rate and breathing rate was wirelessly transmitted. The experimental results showed that the device for non-contact monitoring of respiration and heartbeat waveforms has advantages of small volume, low power consumption, which can realize the monitoring of physiological parameters in real time.


Assuntos
Frequência Cardíaca , Monitorização Fisiológica/instrumentação , Respiração , Humanos , Processamento de Sinais Assistido por Computador
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