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1.
Quant Imaging Med Surg ; 14(5): 3501-3518, 2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38720828

RESUMO

Background: In the field of medical imaging, the rapid rise of convolutional neural networks (CNNs) has presented significant opportunities for conserving healthcare resources. However, with the wide spread application of CNNs, several challenges have emerged, such as enormous data annotation costs, difficulties in ensuring user privacy and security, weak model interpretability, and the consumption of substantial computational resources. The fundamental challenge lies in optimizing and seamlessly integrating CNN technology to enhance the precision and efficiency of medical diagnosis. Methods: This study sought to provide a comprehensive bibliometric overview of current research on the application of CNNs in medical imaging. Initially, bibliometric methods were used to calculate the frequency statistics, and perform the cluster analysis and the co-citation analysis of countries, institutions, authors, keywords, and references. Subsequently, the latent Dirichlet allocation (LDA) method was employed for the topic modeling of the literature. Next, an in-depth analysis of the topics was conducted, and the topics in the medical field, technical aspects, and trends in topic evolution were summarized. Finally, by integrating the bibliometrics and LDA results, the developmental trajectory, milestones, and future directions in this field were outlined. Results: A data set containing 6,310 articles in this field published from January 2013 to December 2023 was complied. With a total of 55,538 articles, the United States led in terms of the citation count, while in terms of the publication volume, China led with 2,385 articles. Harvard University emerged as the most influential institution, boasting an average of 69.92 citations per article. Within the realm of CNNs, residual neural network (ResNet) and U-Net stood out, receiving 1,602 and 1,419 citations, respectively, which highlights the significant attention these models have received. The impact of coronavirus disease 2019 (COVID-19) was unmistakable, as reflected by the publication of 597 articles, making it a focal point of research. Additionally, among various disease topics, with 290 articles, brain-related research was the most prevalent. Computed tomography (CT) imaging dominated the research landscape, representing 73% of the 30 different topics. Conclusions: Over the past 11 years, CNN-related research in medical imaging has grown exponentially. The findings of the present study provide insights into the field's status and research hotspots. In addition, this article meticulously chronicled the development of CNNs and highlighted key milestones, starting with LeNet in 1989, followed by a challenging 20-year exploration period, and culminating in the breakthrough moment with AlexNet in 2012. Finally, this article explored recent advancements in CNN technology, including semi-supervised learning, efficient learning, trustworthy artificial intelligence (AI), and federated learning methods, and also addressed challenges related to data annotation costs, diagnostic efficiency, model performance, and data privacy.

2.
Food Chem ; 440: 138242, 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38154280

RESUMO

For the manufacturing and sale of tea, rapid discrimination of overall quality grade is of great importance. However, present evaluation methods are time-consuming and labor-intensive. This study investigated the feasibility of combining advantages of near-infrared spectroscopy (NIRS) and electronic nose (E-nose) to assess the tea quality. We found that NIRS and E-nose models effectively identify taste and aroma quality grades, with the highest accuracies of 99.63% and 97.00%, respectively, by comparing different principal component numbers and classification algorithms. Additionally, the quantitative models based on NIRS predicted the contents of key substances. Based on this, NIRS and E-nose data were fused in the feature-level to build the overall quality evaluation model, achieving accuracies of 98.13%, 96.63% and 97.75% by support vector machine, K-nearest neighbors, and artificial neural network, respectively. This study reveals that the integration of NIRS and E-nose presents a novel and effective approach for rapidly identifying tea quality.


Assuntos
Camellia sinensis , Chá , Chá/química , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Nariz Eletrônico , Camellia sinensis/química , Algoritmos
3.
Front Hum Neurosci ; 17: 1257987, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38077182

RESUMO

Introduction: Autism Spectrum Disorder (ASD) has a significant impact on the health of patients, and early diagnosis and treatment are essential to improve their quality of life. Machine learning methods, including multi-classifier fusion, have been widely used for disease diagnosis and prediction with remarkable results. However, current multi-classifier fusion methods lack the ability to measure the belief level of different samples and effectively fuse them jointly. Methods: To address these issues, a multi-classifier fusion classification framework based on belief-value for ASD diagnosis is proposed in this paper. The belief-value measures the belief level of different samples based on distance information (the output distance of the classifier) and local density information (the weight of the nearest neighbor samples on the test samples), which is more representative than using a single type of information. Then, the complementary relationships between belief-values are captured via a multilayer perceptron (MLP) network for effective fusion of belief-values. Results: The experimental results demonstrate that the proposed classification framework achieves better performance than a single classifier and confirm that the fusion method used can effectively fuse complementary relationships to achieve accurate diagnosis. Discussion: Furthermore, the effectiveness of our method has only been validated in the diagnosis of ASD. For future work, we plan to extend this method to the diagnosis of other neuropsychiatric disorders.

4.
Hortic Res ; 10(4): uhad028, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-37090093

RESUMO

Tea is one of the most popular healthy and non-alcoholic beverages worldwide. Tea anthracnose is a disease in tea mature leaves and ultimately affects yield and quality. Colletotrichum camelliae is a dominant fungal pathogen in the tea field that infects tea plants in China. The pathogenic factors of fungus and the susceptible factors in the tea plant are not known. In this work, we performed molecular and genetic studies to observe a cerato-platanin protein CcCp1 from C. camelliae, which played a key role in fungal pathogenicity. △CcCp1 mutants lost fungal virulence and reduced the ability to produce conidia. Transcriptome and metabolome were then performed and analysed in tea-susceptible and tea-resistant cultivars, Longjing 43 and Zhongcha 108, upon C. camelliae wild-type CCA and △CcCp1 infection, respectively. The differentially expressed genes and the differentially accumulated metabolites in tea plants were clearly overrepresented such as linolenic acid and linoleic acid metabolism, glycerophospholipid metabolism, phenylalanine biosynthesis and metabolism, biosynthesis of flavonoid, flavone and flavonol etc. In particular, the accumulation of jasmonic acid was significantly increased in the susceptible cultivar Longjing 43 upon CCA infection, in the fungal CcCp1 protein dependent manner, suggesting the compound involved in regulating fungal infection. In addition, other metabolites in the glycerophospholipid and phenylalanine pathway were observed in the resistant cultivar Zhongcha 108 upon fungal treatment, suggesting their potential role in defense response. Taken together, this work indicated C. camelliae CcCp1 affected the tea plant lipid metabolism pathway to promote disease while the lost function of CcCp1 mutants altered the fungal virulence and plant response.

5.
Med Phys ; 50(10): 6269-6282, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36995984

RESUMO

BACKGROUND: The abnormal brain functional connectivity (FC) of patients with mental diseases is closely linked to the transition features among brain states. However, the current research on state transition will produce certain division deviations in the measurement method of state division, and also ignore the transition features among multiple states that contain more abundant information for analyzing brain diseases. PURPOSE: To investigate the potential of the proposed method based on coarse-grained similarity measurement to solve the problem of state division, and consider the transition features among multiple states to analyze the FC abnormalities of autism spectrum disorder (ASD) patients. METHODS: We used resting-state functional magnetic resonance imaging to examine 45 ASD and 47 healthy controls (HC). The FC between brain regions was calculated by the sliding window and correlation algorithm, and a novel coarse-grained similarity measure method was used to cluster the FC networks into five states, and then extract the features both of the state itself and the transition features among multiple states for analysis and diagnosis. RESULTS: (1) The state as divided by the coarse-grained measurement method improves the diagnostic performance of individuals with ASD compared with previous methods. (2) The transition features among multiple states can provide complementary information to the features of the state itself in the ASD analysis and diagnosis. (3) ASD individuals have different brain state transitions than HC. Specifically, the abnormalities in intra- and inter-network connectivity of ASD patients mainly occur in the default mode network, the visual network, and the cerebellum. CONCLUSIONS: Such results demonstrate that our approach with new measurements and new features is effective and promising in brain state analysis and ASD diagnosis.


Assuntos
Transtorno do Espectro Autista , Humanos , Transtorno do Espectro Autista/diagnóstico por imagem , Mapeamento Encefálico/métodos , Imageamento por Ressonância Magnética/métodos , Encéfalo/diagnóstico por imagem , Cerebelo
6.
Molecules ; 27(24)2022 Dec 09.
Artigo em Inglês | MEDLINE | ID: mdl-36557856

RESUMO

Harvesting seasons are crucial for the physicochemical qualities of large-leaf-variety black tea. To investigate the effect of harvesting seasons on physicochemical qualities, the color and sensory characteristics of black tea produced from "Yinghong 9" (Yh) and its mutant "Huangyu" (Hy) leaves were analyzed. The results demonstrated that Hy had better chemical qualities and sensory characteristics, on average, such as a higher content of tea polyphenols, free amino acids, caffeine, galloylated catechins (GaCs) and non-galloylated catechins (NGaCs), while the hue of the tea brew (ΔE*ab and Δb*) increased, which meant that the tea brew was yellower and redder. Moreover, the data showed that the physicochemical qualities of SpHy (Hy processed in spring) were superior to those of SuHy (Hy processed in summer) and AuHy (Hy processed in autumn), and 92.6% of the total variance in PCA score plots effectively explained the separation of the physicochemical qualities of Yh and Hy processed in different harvesting seasons. In summary, Hy processed in spring was superior in its physicochemical qualities. The current results will provide scientific guidance for the production of high-quality large-leaf-variety black tea in South China.


Assuntos
Camellia sinensis , Catequina , Cafeína/análise , Camellia sinensis/química , Catequina/química , Folhas de Planta/química , Estações do Ano , Chá/química
7.
Molecules ; 27(13)2022 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-35807365

RESUMO

Roasting is crucial for producing Yuan An yellow tea (YAYT) as it substantially affects sensory quality. However, the effect of roasting time on YAYT flavor quality is not clear. To investigate the effect of roasting time on the sensory qualities, chemical components, odor profiles, and metabolic profile of YAYTs produced with 13 min roasting, 16 min roasting, 19 min roasting, 22 min roasting, and 25 min roasting were determined. The YAYTs roasted for 22 min got higher sensory scores and better chemical qualities, such as the content of gallocatechin (GC), gallocatechin gallate (GCG), free amino acids, solutable sugar, meanwhile the lightness decreased, the hue of tea brew color (b) increased, which meant the tea brew got darker and yellower. YAYTs roasted for 22 min also increased the contents of key odorants, such as benzaldehyde, nonanal, ß-cyclocitral, linalool, nerol, α-cedrol, ß-ionone, limonene, 2-methylfuran, indole, and longiborneol. Moreover, non-targeted metabolomics identified up to 14 differentially expressed metabolites through pair-wise comparisons, such as flavonoids, phenolic acids, sucrose, and critical metabolites, which were the main components corresponding to YAYT roasted for 22 min. In summary, the current results provide scientific guidance for the production of high quality YAYT.


Assuntos
Paladar , Compostos Orgânicos Voláteis , Temperatura Alta , Odorantes/análise , Chá/química , Compostos Orgânicos Voláteis/análise
8.
Front Nutr ; 9: 1038806, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36687674

RESUMO

Tea is one of the most well-known, healthy beverages in the world. Tea plants produce caffeine as a secondary metabolite. Colletotrichum camelliae is one of the most important microbes frequently isolated from tea fields, and it causes anthracnose disease in tea plant. In the present work, we performed molecular microbiology and transcriptomic analyses of the C. camelliae - tea plant interaction to investigate the mechanism of fungal virulence and plant defense. Upon infection of tea plant with C. camelliae, we observed alterations in the expression of fungal transcripts, including those of many genes associated with caffeine metabolism, such as those encoding various transporters, xanthine dehydrogenase, and urate oxidase (UOX). In particular, the deletion of C. camelliae urate oxidase (CcUOX), which is involved in the caffeine metabolism pathway, reduced fungal tolerance to caffeine, and impaired fungal virulence. CcUOX is involved in caffeine metabolism by the degradation of uric acid contents. C. camelliaeΔCcUOX mutants impaired uric acid degradation in vivo. The CcUOX gene was cloned from C. camelliae, overexpressed in Escherichia coli, and the recombinant CcUOX protein displayed maximum activity at 30°C and a pH of 4.0. The recombinant CcUOX efficiently reduced uric acid in vitro suggesting a promising application in caffeine-contaminated environment management and in producing food with low purine contents to prevent uric acid related human diseases, such as hyperuricemia and gout.

9.
Molecules ; 26(21)2021 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-34771147

RESUMO

This study aimed to compare the effect of hot roller (HR) drying and hot air (HA) drying on the sensory evaluation, chemical quality, antioxidant activity, and metabolic profile of Yihong Congou black tea processed from E'cha NO1. The Yihong Congou black tea dried with HA obtained higher sensory scores and better chemical qualities such as the hue of tea brew color (a and b), content of theaflavins, thearubigins, water extract, free amino acids, tea polyphenol, and the ratio of polyphenol to amino acids as well as higher antioxidant capacities compared to that dried with HR. The HA drying tea increased the contents of volatile compounds that had positive correlation with sweet and flowery flavor, while the HR drying tea increased the contents of volatile compounds related to fruity flavor. Moreover, non-targeted metabolomics data indicated that the levels of most free amino acids significantly increased, while the levels of most soluble sugars reduced in the HA drying method compared to the HR drying method. The metabolic analysis was also consistent with the above results and revealed that D-ribose and gallic acid were the main characteristic metabolites of HA drying. Our results could provide a technical reference and theoretical guide to processing a high quality of Yihong Congou black tea.


Assuntos
Aminoácidos/metabolismo , Aromatizantes/metabolismo , Metabolômica , Polifenóis/metabolismo , Chá/metabolismo , Temperatura , Aminoácidos/química , Aromatizantes/química , Conservação de Alimentos , Polifenóis/química , Chá/química
10.
J Agric Food Chem ; 67(23): 6672-6682, 2019 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-31117493

RESUMO

To investigate the effects of grafting on non-volatile metabolites in tea, non-targeted metabolomic analyses of fresh leaves were performed on the basis of ultra-high-performance liquid chromatography quadrupole time-of-flight tandem mass spectrometry (UHPLC-QTOF/MS). One non-grafted YingHong No. 9 and four grafted tea [grafting scion YingHong No. 9 on four different rootstocks, BaiMao No. 2 (BM2), BaiYeDanCong (BY), HeiYeShuiXian (HY), and WuLingHong (WLH)] were chosen as materials. In total, 32 differential metabolites were identified, including phenolic acids, flavan-3-ols, dimeric catechins, flavonol and flavonol/flavone glycosides, etc. Partial least squares discrimination analysis and hierarchical cluster analysis showed various effects of different rootstocks on metabolites. Thereinto, rootstocks of WLH and BY showed extremely outstanding performance in up- and downregulating these metabolites, respectively. Differential metabolites were enriched into three crucial pathways, including biosynthesis of phenylpropanoids, flavonoid biosynthesis, and flavone and flavonol biosynthesis, which might influence the quality of tea. This study provides a theoretical basis for grafting-related variations of non-volatile metabolites in fresh tea leaves.


Assuntos
Camellia sinensis/química , Extratos Vegetais/química , Folhas de Planta/química , Camellia sinensis/metabolismo , Cromatografia Líquida de Alta Pressão , Metabolômica , Melhoramento Vegetal , Folhas de Planta/metabolismo , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , Espectrometria de Massas em Tandem
11.
Sci Rep ; 9(1): 433, 2019 01 23.
Artigo em Inglês | MEDLINE | ID: mdl-30674986

RESUMO

Tea (Camellia sinensis) leaves are used to make the most widely consumed beverage globally after water. Therefore, the safety and quality of raw tea leaves are important indices for making tea and related products. Habitat management has been widely used as an environmentally friendly method to control pests in agroecosystems. To investigate the impact of habitat management on tea plantation ecosystems, a habitat management approach with intercropping was established. The function of habitat management on pest control was evaluated. Furthermore, metabolome and transcriptome analysis were applied to assay changes in quality-related metabolites. The habitat management approach was found to maintain arthropod biodiversity and develop natural arthropod enemies in the tea plantation. Therefore, the yield of the habitat management-treated tea plantation was increased. Metabolome analysis showed that epigallocatechin-3-gallate, the major catechin in tea leaves, has a significantly increased content in leaves of tea plants under habitat management compared with those in the control tea plantation. The content of L-theanine, the major amino acid in tea leaves, was not significantly changed in tea plants under habitat management. Furthermore, aroma compounds were more abundant in tea leaves from the habitat management-treated tea plantation than those from the chemical pesticide-treated tea plantation. Therefore, habitat management is reported for the first time as a safe and effective approach to improving the yield and quality of tea leaves.


Assuntos
Camellia sinensis/crescimento & desenvolvimento , Catequina/análogos & derivados , Produção Agrícola , Ecossistema , Metabolômica , Folhas de Planta/crescimento & desenvolvimento , Catequina/biossíntese
12.
BMC Plant Biol ; 17(1): 206, 2017 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-29157222

RESUMO

BACKGROUND: A recently discovered tea [Camellia sinensis (L.) O. Kuntze] cultivar can generate tender shoots in winter. We performed comparative proteomics to analyze the differentially accumulated proteins between winter and spring tender shoots of this clonal cultivar to reveal the physiological basis of its evergrowing character during winter. RESULTS: We extracted proteins from the winter and spring tender shoots (newly formed two leaves and a bud) of the evergrowing tea cultivar "Dongcha11" respectively. Thirty-three differentially accumulated high-confidence proteins were identified by matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF / TOF MS). Among these, 24 proteins had increased abundance while nine showed were decreased abundance in winter tender shoots as compared with the spring tender shoots. We categorized the differentially accumulated proteins into eight critical biological processes based on protein function annotation including photosynthesis, cell structure, protein synthesis & destination, transporters, metabolism of sugars and polysaccharides, secondary metabolism, disease/defense and proteins with unknown functions. Proteins with increased abundance in winter tender shoots were mainly related to the processes of photosynthesis, cytoskeleton and protein synthesis, whereas those with decreased abundance were correlated to metabolism and the secondary metabolism of polyphenolic flavonoids. Biochemical analysis showed that the total contents of soluble sugar and amino acid were higher in winter tender shoots while tea polyphenols were lower as compared with spring tender shoots. CONCLUSIONS: Our study suggested that the simultaneous increase in the abundance of photosynthesis-related proteins rubisco, plastocyanin, and ATP synthase delta chain, metabolism-related proteins eIF4 and protease subunits, and the cytoskeleton-structure associated proteins phosphatidylinositol transfer protein and profilin may be because of the adaptation of the evergrowing tea cultivar "Dongcha11" to low temperature and light conditions. Histone H4, Histone H2A.1, putative In2.1 protein and protein lin-28 homologs may also regulate the development of winter shoots and their response to adverse conditions.


Assuntos
Camellia sinensis/crescimento & desenvolvimento , Brotos de Planta/fisiologia , Proteômica/métodos , Camellia sinensis/fisiologia , Eletroforese em Gel Bidimensional , Luz , Espectrometria de Massas , Fotossíntese/fisiologia , Proteínas de Plantas/análise , Proteínas de Plantas/fisiologia , Brotos de Planta/química , Reação em Cadeia da Polimerase em Tempo Real , Estações do Ano , Temperatura
13.
Rev Sci Instrum ; 87(10): 105107, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27802703

RESUMO

Researches on monitoring the body fluid changes have attracted much attention during recent years. Real-time bioimpedance deviation detection has good potential for evaluating body fluid changes. In this paper, an improved device based on the self-balancing half bridge and the 4-electrode technique is proposed, which is able to detect minor bioimpedance deviations. The 4-electrode technique is used to remove the interference from contact impedance. Furthermore, the automatic balancing half bridge is utilized to deduct the high-level static impedance baseline, and thus, the dynamic range is enlarged. Moreover, a digital lock-in algorithm based on oversampling improved the effective resolution of the system. Validation experiments show that the minimum bioimpedance deviation measured in the experiment can reach 1 Ω even when the bioimpedance baseline is 10 kΩ and the noise level is low. The system has advantages of high resolution, high magnification, large dynamic range, and good self-adaptability for bioimpedance deviation detection.


Assuntos
Líquidos Corporais , Impedância Elétrica , Animais , Eletrodos , Humanos
14.
J Biomed Opt ; 20(1): 015004, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25621873

RESUMO

Nitric oxide (NO) has key regulatory roles in various biological and medical processes. The control of its local concentration, which is crucial for obtaining the desired effect, can be achieved with exogenous NO donors. Release of NO from metal-nitrosyl complexes upon exposure to light is a strategy that could allow for the site-specific delivery of the reactive species NO to physiological targets. The photodissociation of NO from two nitrosylruthenium(II) isomer complexes {cis- and trans-[Ru(OAc)(2mqn)(2)NO]} was demonstrated by matrix-assisted laser desorption ionization time-of-flight mass spectrometry spectra, and electron paramagnetic resonance spectra further prove the photoinduced NO release by spin trapping of NO free radicals upon photoirradiation. Real-time NO release was quantitatively measured by electrochemistry with an NO-specific electrode. The quantitative control of NO release from [Ru(OAc)(2mqn)(2)NO] in aqueous solutions was done by photoirradiation at different wavelengths. Both isomers show photoinduced damage on plasmid DNA, but the trans isomer has higher cytotoxicity and photocytotoxicity activity against the HeLa tumor cell line than that of the cis isomer. Nitrosylruthenium(II) complex, with 8-quinolinol derivatives as ligands, has a great potential as a photoactivated NO donor reagent for biomedical applications.


Assuntos
Óxido Nítrico/química , Óxido Nítrico/farmacocinética , Compostos de Rutênio/química , Antineoplásicos/química , Antineoplásicos/farmacocinética , Sobrevivência Celular/efeitos da radiação , Dano ao DNA/efeitos da radiação , Células HeLa , Humanos , Modelos Moleculares , Processos Fotoquímicos
15.
Phys Chem Chem Phys ; 16(43): 24045-54, 2014 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-25285659

RESUMO

In this work, the photoisomerization and structural dynamics of two isomeric nitrosylruthenium(ii) complexes [Ru(OAc)(2cqn)2NO] (H2cqn = 2-chloro-8-quinolinol) in CDCl3 and DMSO are examined using NMR and IR spectroscopic methods. The two N atoms in the 2cqn ligand are in trans position in the synthesized cis-1 isomer, while they are in cis position in the cis-2 isomer. Kinetics monitored by NMR spectroscopy shows that the rate constant of photoisomerization from cis-2 to cis-1 isomer depends on the wavelength of irradiation and solvent polarity; it proceeds faster on irradiating near the absorption peak in the UV-Vis region, and also in more polar solvents (DMSO). Density functional theory computation indicates that the peculiarity of [Ru(ii)-NO(+)] group affects the structure and reactivity of the nitrosylruthenium complexes. Using the nitrosyl stretching (νNO) to be vibrational probe, the structural dynamics and structural distributions of the cis-1 and cis-2 isomers are examined by steady-state linear infrared and ultrafast two-dimensional infrared (2D IR) spectroscopies. The structural and photochemical aspects of the observed spectroscopic parameters are discussed in terms of solute-solvent interactions for the two nitrosylruthenium complexes.

16.
Rev Sci Instrum ; 85(5): 055111, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24880419

RESUMO

The stability and signal to noise ratio (SNR) of the current source circuit are the important factors contributing to enhance the accuracy and sensitivity in bioimpedance measurement system. In this paper we propose a new differential Howland topology current source and evaluate its output characters by simulation and actual measurement. The results include (1) the output current and impedance in high frequencies are stabilized after compensation methods. And the stability of output current in the differential current source circuit (DCSC) is 0.2%. (2) The output impedance of two current circuits below the frequency of 200 KHz is above 1 MΩ, and below 1 MHz the output impedance can arrive to 200 KΩ. Then in total the output impedance of the DCSC is higher than that of the Howland current source circuit (HCSC). (3) The SNR of the DCSC are 85.64 dB and 65 dB in the simulation and actual measurement with 10 KHz, which illustrates that the DCSC effectively eliminates the common mode interference. (4) The maximum load in the DCSC is twice as much as that of the HCSC. Lastly a two-dimensional phantom electrical impedance tomography is well reconstructed with the proposed HCSC. Therefore, the measured performance shows that the DCSC can significantly improve the output impedance, the stability, the maximum load, and the SNR of the measurement system.


Assuntos
Espectroscopia Dielétrica , Pletismografia de Impedância , Razão Sinal-Ruído , Espectroscopia Dielétrica/instrumentação , Espectroscopia Dielétrica/métodos , Impedância Elétrica , Pletismografia de Impedância/instrumentação , Pletismografia de Impedância/métodos
17.
Zhonghua Yu Fang Yi Xue Za Zhi ; 42(2): 93-5, 2008 Feb.
Artigo em Chinês | MEDLINE | ID: mdl-18642660

RESUMO

OBJECTIVE: To explore the level and feature of neonate deformity in water arsenic exposure areas, as to finding out an evidence for the study and prevention of the arsenic exposure. METHODS: The birth situation of neonate was surveyed from 1998 to 2004 in water arsenic exposure areas according to cross-sectional survey. The results were classified in accordance with ICD-10 and common surveillance of china. The population of Shanyin County served as the common people and the data were analyzed by SPSS 11.5 for windows. RESULTS: The neonates surveyed were 2467 cases. There were 49 neonates deformity found in this investigation, giving a neonate deformity rate of 198.62 per 10,000 cases, which was shown significantly higher in water arsenic exposure areas than in the normal (U = 3.23, P < 0.01), with types of nervous system deformity, limbs deformity and congenital heart disease as in system classification. There was no significant difference of deformity rate in different sex neonates (chi2 = 0.32, P > 0.05). CONCLUSION: The drinking high-arsenic water over a long period of time should be a risk factor of neonate deformity. Prevention and treatment of endemic arsenic exposure should be urgently needed.


Assuntos
Intoxicação por Arsênico/epidemiologia , Arsênio/análise , Anormalidades Congênitas/epidemiologia , Poluentes Químicos da Água/análise , Intoxicação por Arsênico/complicações , Anormalidades Congênitas/etiologia , Estudos Transversais , Exposição Ambiental/análise , Feminino , Humanos , Recém-Nascido , Masculino , Água/análise , Abastecimento de Água/análise
18.
Environ Health Perspect ; 115(4): 643-7, 2007 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-17450237

RESUMO

BACKGROUND: Recently, in a cross-sectional study of 201 children in Araihazar, Bangladesh, exposure to arsenic (As) in drinking water has been shown to lower the scores on tests that measure children's intellectual function before and after adjustment for sociodemographic features. OBJECTIVES: We investigated the effects of As and fluoride exposure on children's intelligence and growth. METHODS: We report the results of a study of 720 children between 8 and 12 years of age in rural villages in Shanyin county, Shanxi province, China. The children were exposed to As at concentrations of 142 +/- 106 microg/L (medium-As group) and 190 +/- 183 microg/L (high-As group) in drinking water compared with the control group that was exposed to low concentrations of As (2 +/- 3 microg/L) and low concentrations of fluoride (0.5 +/- 0.2 mg/L). A study group of children exposed to high concentrations of fluoride (8.3 +/- 1.9 mg/L) but low concentrations of As (3 +/- 3 microg/L) was also included because of the common occurrence of elevated concentrations of fluoride in groundwater in our study area. A standardized IQ (intelligence quotient) test was modified for children in rural China and was based on the classic Raven's test used to determine the effects of these exposures on children's intelligence. A standardized measurement procedure for weight, height, chest circumference, and lung capacity was used to determine the effects of these exposures on children's growth. RESULTS: The mean IQ scores decreased from 105 +/- 15 for the control group, to 101 +/- 16 for the medium-As group (p < 0.05), and to 95 +/- 17 for the high-As group (p < 0.01). The mean IQ score for the high-fluoride group was 101 +/- 16 and significantly different from that of the control group (p < 0.05). Children in the control group were taller than those in the high-fluoride group (p < 0.05); weighed more than the those in the high-As group (p < 0.05); and had higher lung capacity than those in the medium-As group (p < 0.05). CONCLUSIONS: Children's intelligence and growth can be affected by high concentrations of As or fluoride. The IQ scores of the children in the high-As group were the lowest among the four groups we investigated. It is more significant that high concentrations of As affect children's intelligence. It indicates that arsenic exposure can affect children's intelligence and growth.


Assuntos
Arsênio/efeitos adversos , Exposição Ambiental , Fluoretos/efeitos adversos , Inteligência , Poluentes da Água/efeitos adversos , Abastecimento de Água , Estatura , Peso Corporal , Estudos de Casos e Controles , Criança , Desenvolvimento Infantil , China , Feminino , Humanos , Masculino , População Rural
19.
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi ; 23(6): 1218-21, 2006 Dec.
Artigo em Chinês | MEDLINE | ID: mdl-17228712

RESUMO

In this paper, different acupoints are stimulated by using pulse stimulating signals with different frequency. The correlation between input signal from acupoints and output signal from brain band is studied. A method to optimize input of acupoints is obtained by an experiment system. And the dynamic connection between meridian and brain band is identified. Experiment has shown that there exists maximal correlation between the signal of 30 Hz intermittent pulse stimulation and the induced cerebral alpha band. And the 30 Hz intermittent pulse stimulation can induce more beneficial cerebral a band.


Assuntos
Pontos de Acupuntura , Encéfalo/fisiologia , Eletroacupuntura , Eletroencefalografia , Processamento de Sinais Assistido por Computador , Adolescente , Adulto , Feminino , Humanos , Masculino
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