Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 10 de 10
Filtrar
Mais filtros










Base de dados
Tipo de estudo
Intervalo de ano de publicação
1.
Parasit Vectors ; 12(1): 543, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31730024

RESUMO

BACKGROUND: Cryptosporidium spp. and Giardia duodenalis are major intestinal pathogens that can cause diarrheal diseases in humans, especially children. Enterocytozoon bieneusi is another parasite which can cause gastrointestinal tract disorders, with diarrhea being the main clinical symptom. However, few genetic studies of these parasites in pediatric inpatients in China have been published. METHODS: To assess the genetic characteristics and epidemiological status of these parasites, a total of 2284 fecal samples were collected from children in the pediatric departments of three hospitals in Zhengzhou, central China, and screened for these protozoans with PCR, based on the small subunit ribosomal RNA (SSU rRNA) genes of Cryptosporidium spp. and G. duodenalis and the internal transcribed spacer (ITS) of E. bieneusi. RESULTS: Six (0.26%), 14 (0.61%), and 27 (1.18%) of the samples were positive for Cryptosporidium spp., G. duodenalis and E. bieneusi, respectively. Of the 12 successfully sequenced G. duodenalis isolates, four were identified as assemblage A and eight as assemblage B. In subtype and multilocus genotype (MLG) analyses, C. parvum IIdA19G1 (n = 4) and two novel G. duodenalis MLGs belonging to subassemblage AII (n = 3) and BIV (n = 5) were successfully identified. The E. bieneusi isolates included genotypes D (n = 17), J (n = 2), PigEBITS7 (n = 1), BEB6 (n = 1), and CM8 (n = 1). This is the first report of C. parvum subtype IIdA19G1 in HIV-negative children and E. bieneusi genotype CM8 in humans. CONCLUSIONS: The dominance of zoonotic C. parvum subtype IIdA19G1 indicates that this parasite is turning into zoonotic origin from human-to-human transmission. The phylogenetic analysis also revealed the zoonotic origins and anthroponotic transmission potential of G. duodenalis and E. bieneusi, suggesting more efforts must be made to minimize the threat these pathogens pose to public health.


Assuntos
Cryptosporidium/classificação , Cryptosporidium/genética , Enterocytozoon/classificação , Enterocytozoon/genética , Fezes/parasitologia , Giardia lamblia/classificação , Giardia lamblia/genética , Adolescente , Criança , Criança Hospitalizada , Pré-Escolar , China , Análise por Conglomerados , Criptosporidiose/parasitologia , Cryptosporidium/isolamento & purificação , DNA de Protozoário/química , DNA de Protozoário/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Transmissão de Doença Infecciosa , Enterocytozoon/isolamento & purificação , Feminino , Variação Genética , Genótipo , Giardia lamblia/isolamento & purificação , Giardíase/parasitologia , Hospitais Pediátricos , Humanos , Lactente , Masculino , Microsporidiose/parasitologia , Filogenia , RNA Ribossômico 18S/genética , Análise de Sequência de DNA
2.
Micromachines (Basel) ; 10(11)2019 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-31652696

RESUMO

Flexible pressure sensors have attracted tremendous attention from researchers for their widely applications in tactile artificial intelligence, electric skin, disease diagnosis, and healthcare monitoring. Obtaining flexible pressure sensors with high sensitivity in a low cost and convenient way remains a huge challenge. In this paper, the composite dielectric layer based on the mixture of carbon nanotubes (CNTs) with different aspect ratios and polydimethylsiloxane (PDMS) was employed in flexible capacitive pressure sensor to increase its sensitivity. In addition, the screen printing instead of traditional etching based methods was used to prepare the electrodes array of the sensor. The results showed that the aspect ratio and weight fraction of the CNTs play an important role in improving the sensitivity of the printed capacitive pressure sensor. The prepared capacitive sensor with the CNTs/PDMS composite dielectric layer demonstrated a maximum sensitivity of 2.9 kPa-1 in the pressure range of 0-450 Pa, by using the CNTs with an aspect ratio of 1250-3750 and the weight fraction of 3.75%. The mechanism study revealed that the increase of the sensitivity of the pressure sensor should be attributed to the relative permittivity increase of the composite dielectric layer under pressure. Meanwhile, the printed 3 × 3 and 10 × 10 sensor arrays showed excellent spatial resolution and uniformity when they were applied to measure the pressure distribution. For further applications, the flexible pressure sensor was integrated on an adhesive bandage to detect the finger bending, as well as used to create Morse code by knocking the sensor to change their capacitance curves. The printed and flexible pressure sensor in this study might be a good candidate for the development of tactile artificial intelligence, intelligent medical diagnosis systems and wearable electronics.

3.
Nanoscale Res Lett ; 14(1): 197, 2019 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-31172304

RESUMO

Highly conductive ink with low sintering temperature is important for printed electronics on paper substrate. Silver nanoparticles (Ag NPs) of different average radii ranging from 48 to 176 nm were synthesized by adjusting the Ag+ concentration in the reaction process. The electric resistivity of the Ag NP-based ink film in relation to Ag NP size, sintering temperature, amount of PVP capping agent on Ag NP surface, and morphology evolution of the film during heating process was investigated. It was found that the resistivity of the films reduced very rapidly with increasing particle size due above all to reduced amount of protective agent capping on the Ag NPs. A semi-empirical relationship between the resistivity and the particle size was proposed. With the help of this mathematical expression, one gains both systematic and detailed insight to the resistivity evaluation with regard to the Ag particle size. The optimal electric resistivity of 4.6 µΩ cm was achieved at 140 °C for 10 min which was very close to the resistivity value of bulk Ag (1.58 µΩ cm). Mechanical flexibility of the printed electronics with the Ag NP-based ink on paper substrates was investigated. The prints on the art coated paper exhibited better flexibility compared to that on the photopaper. This might be attributed to the surface coating composition, surface morphology of the paper, and their corresponding ink absorption property.

4.
Int J Mol Sci ; 20(9)2019 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-31036787

RESUMO

Printed electronics on flexible substrates has attracted tremendous research interest research thanks its low cost, large area production capability and environmentally friendly advantages. Optimal characteristics of silver nanoparticles (Ag NPs) based inks are crucial for ink rheology, printing, post-print treatment, and performance of the printed electronics devices. In this review, the methods and mechanisms for obtaining Ag NPs based inks that are highly conductive under moderate sintering conditions are summarized. These characteristics are particularly important when printed on temperature sensitive substrates that cannot withstand sintering of high temperature. Strategies to tailor the protective agents capping on the surface of Ag NPs, in order to optimize the sizes and shapes of Ag NPs as well as to modify the substrate surface, are presented. Different (emerging) sintering technologies are also discussed, including photonic sintering, electrical sintering, plasma sintering, microwave sintering, etc. Finally, applications of the Ag NPs based ink in transparent conductive film (TCF), thin film transistor (TFT), biosensor, radio frequency identification (RFID) antenna, stretchable electronics and their perspectives on flexible and printed electronics are presented.


Assuntos
Eletrônica/métodos , Tinta , Nanopartículas Metálicas , Impressão , Prata , Técnicas Biossensoriais , Condutividade Elétrica , Eletrônica/instrumentação , Nanopartículas Metálicas/química , Modelos Teóricos , Impressão/métodos , Prata/química , Análise Espectral , Temperatura
5.
Parasitology ; 144(14): 1890-1897, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28697813

RESUMO

To investigate the prevalence of Cyclospora cayetanensis in a longitudinal study and to conduct a population genetic analysis, fecal specimens from 6579 patients were collected during the cyclosporiasis - prevalent seasons in two urban areas of central China in 2011-2015. The overall incidence of C. cayetanensis infection was 1·2% (76/6579): 1·6% (50/3173) in Zhengzhou and 0·8% (26/3406) in Kaifeng (P 0·05). All the isolates clustered in the C. cayetanensis clade based on the small subunit ribosomal RNA gene sequence phylogenetic analysis. There were 45 specimens positive for all the five C. cayetanensis microsatellite loci, and formed 29 multilocus genotypes (MLGs). The phylogenetic relationships of 54 distinct MLGs (including 25 known reference MLGs), based on the concatenated multilocus sequences, formed three main clusters. A population structure analysis showed that the 79 isolates (including 34 known reference isolates) of C. cayetanensis produced three distinct subpopulations based on allelic profile data. In conclusion, we determined the frequency of C. cayetanensis infection in humans in Henan Province. The clonal population structure of the human C. cayetanensis isolates showed linkage disequilibrium and three distinct subpopulations.


Assuntos
Cyclospora/genética , Ciclosporíase/parasitologia , Variação Genética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , China/epidemiologia , Cyclospora/classificação , Ciclosporíase/epidemiologia , Feminino , Humanos , Incidência , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Tipagem de Sequências Multilocus , Filogenia , Prevalência , Adulto Jovem
6.
Zhonghua Yi Xue Yi Chuan Xue Za Zhi ; 33(1): 9-12, 2016 Feb.
Artigo em Chinês | MEDLINE | ID: mdl-26829724

RESUMO

OBJECTIVE: To assess the value of eight-probe fluorescence in situ hybridization (FISH) and R-banding karyotype analysis for the diagnosis of acute lymphoblastic leukemia (ALL). METHODS: With the eight-probe FISH (using probes for MYC, P16, E2A, CHIC2/D10Z1/D17Z1, TEL/AMLl, MLL, BCR/ABL1, and IGH) and R-banding karyotype analysis, 237 cases of ALL were analyzed. RESULTS: Cytogenetic changes were detected in 135 (56.96%) of all cases, which have involved MYC, P16, E2A, CHIC2/D10Z1/D17Z1, TEL/AMLl, MLL, BCR/ABL1, and IGH polyploidies. R-banding karyotype analysis has only detected abnormalities in 48 of such cases, in addition with 14 abnormalities missed by the FISH probes, which have given a total positive rate of 26.16%. The detection rate of the two methods has differed significantly(P<0.05). CONCLUSION: Compared with the R-banding karyotype analysis, the eight-probe FISH is more accurate and efficient. Diagnosis of cytogenetic abnormalities for children with ALL using the combined method can provide a basis for evaluation of prognosis as well as personalized therapy.


Assuntos
Bandeamento Cromossômico/métodos , Testes Genéticos/métodos , Hibridização in Situ Fluorescente/métodos , Cariotipagem/métodos , Leucemia-Linfoma Linfoblástico de Células Precursoras/diagnóstico , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Aberrações Cromossômicas , Humanos
7.
Zhonghua Yi Xue Yi Chuan Xue Za Zhi ; 32(3): 378-80, 2015 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-26037355

RESUMO

OBJECTIVE: To explore the source and morphology of supernumerary markers from patients with 47,XYY/47,XY, +mar and supermale syndrome. METHODS: Conventional GTG banded karyotyping and dual-color fluorescence in situ hybridization (FISH) were performed on 21 such patients. RESULTS: Among these cases, 18 had their small supernumerary marker derived from the Y chromosome. Three were derived from autosomal chromosomes. Those derived from Y chromosome were small fragments with centromeres, while those derived from autosomes were in the ring form. CONCLUSION: In children with supermale syndrome and 47,XYY/47,XY,+ mar, the supernumerary marker chromosomes primarily derive from sex chromosomes. These small chromosomes mainly have the forms of small segments with centromeres or rings. For such children, molecular cytogenetic analysis can facilitate genetic counseling and prenatal diagnosis.


Assuntos
Transtornos dos Cromossomos Sexuais/genética , Cariótipo XYY/genética , Adolescente , Criança , Pré-Escolar , Aberrações Cromossômicas , Bandeamento Cromossômico , Humanos , Hibridização in Situ Fluorescente , Lactente , Masculino
8.
Zhonghua Yi Xue Yi Chuan Xue Za Zhi ; 31(4): 472-5, 2014 Aug.
Artigo em Chinês | MEDLINE | ID: mdl-25119913

RESUMO

OBJECTIVE: To investigate the genetic cause for a large family affected with typeⅠosteogenesis imperfecta. METHODS: Genomic DNA was extracted from peripheral venous blood samples. The entire coding region and intron-exon boundaries of the COL1A1 gene were subjected to PCR amplification and direct sequencing. Total RNA was also extracted from immortalized B cell lines from the patients, with the first strand of cDNA synthesized with an oligo(dT)18 primer. The PCR products were directly sequenced using the TA cloned plasmid. RESULTS: A c.3208G>A mutation has been identified in the COL1A1 gene, which can alter the splicing pattern of mRNA. CONCLUSION: A novel splicing mutation c.3208G>A of the COL1A1 gene probably underlies the disease.


Assuntos
Colágeno Tipo I/genética , Osteogênese Imperfeita/genética , Mutação Puntual , Processamento de RNA , Adolescente , Adulto , Grupo com Ancestrais do Continente Asiático/genética , Sequência de Bases , Criança , Pré-Escolar , Feminino , Humanos , Masculino , Dados de Sequência Molecular , Linhagem , Adulto Jovem
9.
Zhonghua Yi Xue Yi Chuan Xue Za Zhi ; 31(2): 189-91, 2014 Apr.
Artigo em Chinês | MEDLINE | ID: mdl-24711029

RESUMO

OBJECTIVE: To study a family affected with osteogenesis imperfecta for potential mutations in COL1A1 gene. METHODS: Clinical data of an affected family was collected. Potential mutation of the COL1A1 gene was screened using polymerase chain reaction and direct sequencing. Suspected mutation was detected in 20 unaffected relatives and 200 unrelated healthy controls. RESULTS: Analysis of RNA splicing has revealed a c.3208G/A mutation, which created a new splice sites and led to a frameshift mutation. The same mutation was not detected in the unaffected relatives or the 200 healthy controls. CONCLUSION: Mutations of the COL1A1 gene are one of the major causes of osteogenesis imperfecta in Chinese population. Our finding has enriched the mutation spectrum of type I collagen genes.


Assuntos
Colágeno Tipo I/genética , Mutação , Osteogênese Imperfeita/genética , Processamento de RNA , Adulto , Pré-Escolar , Feminino , Humanos , Masculino
10.
Gene ; 502(2): 168-71, 2012 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-22565191

RESUMO

Osteogenesis imperfect (OI) is a heritable connective tissue disorder with bone fragility as a cardinal manifestation, accompanied by short stature, dentinogenesis imperfecta, hyperlaxity of ligaments and skin, blue sclerae and hearing loss. Dominant form of OI is caused by mutations in the type I procollagen genes, COL1A1/A2. Here we identified a novel splicing mutation c.3207+1G>A (GenBank ID: JQ236861) in the COL1A1 gene that caused type I OI in a Chinese family. RNA splicing analysis proved that this mutation created a new splicing site at c.3200, and then led to frameshift. This result further enriched the mutation spectrum of type I procollagen genes.


Assuntos
Colágeno Tipo I/genética , Mutação , Osteogênese Imperfeita/genética , Processamento de RNA , Grupo com Ancestrais do Continente Asiático , Pré-Escolar , Feminino , Humanos , Masculino , Linhagem , Adulto Jovem
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA