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2.
Nat Commun ; 13(1): 7346, 2022 12 05.
Artigo em Inglês | MEDLINE | ID: mdl-36470898

RESUMO

Although machine learning (ML) has shown promise across disciplines, out-of-sample generalizability is concerning. This is currently addressed by sharing multi-site data, but such centralization is challenging/infeasible to scale due to various limitations. Federated ML (FL) provides an alternative paradigm for accurate and generalizable ML, by only sharing numerical model updates. Here we present the largest FL study to-date, involving data from 71 sites across 6 continents, to generate an automatic tumor boundary detector for the rare disease of glioblastoma, reporting the largest such dataset in the literature (n = 6, 314). We demonstrate a 33% delineation improvement for the surgically targetable tumor, and 23% for the complete tumor extent, over a publicly trained model. We anticipate our study to: 1) enable more healthcare studies informed by large diverse data, ensuring meaningful results for rare diseases and underrepresented populations, 2) facilitate further analyses for glioblastoma by releasing our consensus model, and 3) demonstrate the FL effectiveness at such scale and task-complexity as a paradigm shift for multi-site collaborations, alleviating the need for data-sharing.


Assuntos
Big Data , Glioblastoma , Humanos , Aprendizado de Máquina , Doenças Raras , Disseminação de Informação
3.
Am J Cancer Res ; 12(10): 4721-4736, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36381324

RESUMO

N-linked glycosylation of proteins is one of the post-translational modifications (PTMs) that shield tumor antigens from immune attack. Signaling lymphocytic activation molecule family 7 (SLAMF7) suppresses cancer cell phagocytosis and is an ideal target under clinical development. PTM of SLAMF7, however, remains less understood. In this study, we investigated the role of N-glycans on SLAMF7 in breast cancer progression. We identified seven N-linked glycosylation motifs on SLAMF7, which are majorly occupied by complex structures. Evolutionally conserved N98 residue is enriched with high mannose and sialylated glycans. Hyperglycosylated SLAMF7 was associated with STT3A expression in breast cancer cells. Inhibition of STT3A by a small molecule inhibitor, N-linked glycosylation inhibitor-1 (NGI-1), reduced glycosylation of SLAMF7, resulting in enhancing antibody affinity and phagocytosis. To provide an on-target effect, we developed an antibody-drug conjugate (ADC) by coupling the anti-SLAMF7 antibody with NGI-1. Deglycosylation of SLAMF7 increases antibody recognition and promotes macrophage engulfment of breast cancer cells. Our work suggests deglycosylation by ADC is a potential strategy to enhance the response of immunotherapeutic agents.

4.
Transl Oncol ; 21: 101443, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35523009

RESUMO

PURPOSE: Cancer patients with COVID-19 likely express biomarker changes in circulation. However, the biomarkers used in SARS-CoV-2 infected cancer patients for COVID-19 severity and prognosis are largely unclear. Therefore, this systematic review aims to determine what biomarkers were measured in cancer patients with COVID-19 and their prognostic utility. METHODS: A systematic literature review in PubMed, Embase, and Scopus was performed on June 16th, 2021. The search keywords coronavirus, neoplasm, biomarkers, and disease progression were used to filter out 17 eligible studies, which were then carefully evaluated. RESULTS: A total of 4,168 patients, 16 types of cancer, and 60 biomarkers were included. Seven up-regulated markers, including CRP, d-dimer, ferritin, IL-2R, IL-6, LDH, and PCT, were identified in eligible studies. Albumin and hemoglobin were significantly down-regulated in cancer patients with COVID-19. Moreover, we observed that the SARS-CoV-2 infected cancer patients with lower CRP, ferritin, and LDH levels successfully survived from COVID-19 treatments. CONCLUSION: Several important clinical biomarkers, such as CRP, ferritin, and LDH, may serve as the prognostic markers to predict the outcomes following COVID-19 treatment and monitor the deterioration of COVID-19 in cancer patients.

5.
Br J Clin Pharmacol ; 88(1): 145-154, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34080719

RESUMO

AIMS: This study aimed to evaluate and compare the effectiveness and safety between clopidogrel and ticagrelor in acute coronary syndrome (ACS) with renal dysfunction. METHODS: We conducted a retrospective cohort study on patients on chronic dialysis and whose admission diagnosis between 1 July 2013 and 31 December 2016 included ACS. The primary effectiveness endpoint was a major adverse cardiovascular event (MACE), and the primary safety endpoint was a major bleeding event. The application of propensity scores through the inverse probability of treatment weighting (IPTW) was applied to the study groups. Cox regression was used to estimate hazard ratios (aHRs) of study endpoints. In addition, the competing risk was adjusted using the Fine and Gray competing risk model. RESULTS: There were 1915 patients in the clopidogrel group and 270 patients in the ticagrelor group. At 12 months, the ticagrelor group had higher risks for MACE (aHR with IPTW: 1.29; 95% CI 1.16-1.44); death (aHR with IPTW: 1.65; 95% CI 1.47-1.86) and cardiac death (subdistribution HR [SHR] with IPTW: 1.64; 95% CI 1.41-1.91), compared with those in the clopidogrel group. For major bleeding event, the risk was significantly higher with ticagrelor than with clopidogrel (SHR with IPTW: 1.49; 95% CI 1.34-1.65). In terms of the risk for any bleeding event, there was no significant difference between the two groups (SHR with IPTW: 1.05; 95% CI 0.95-1.17). CONCLUSIONS: Compared with clopidogrel, ticagrelor was associated with higher MACE, death, cardiac death and major bleeding risk within 12 months in patients with ACS and on dialysis.


Assuntos
Síndrome Coronariana Aguda , Intervenção Coronária Percutânea , Síndrome Coronariana Aguda/tratamento farmacológico , Clopidogrel/efeitos adversos , Hemorragia/induzido quimicamente , Hemorragia/epidemiologia , Humanos , Inibidores da Agregação Plaquetária/efeitos adversos , Antagonistas do Receptor Purinérgico P2Y/efeitos adversos , Diálise Renal , Estudos Retrospectivos , Taiwan/epidemiologia , Ticagrelor/efeitos adversos , Resultado do Tratamento
6.
Am J Cancer Res ; 11(10): 4994-5005, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34765306

RESUMO

SARS-CoV-2 exploits the host cellular machinery for virus replication leading to the acute syndrome of coronavirus disease 2019 (COVID-19). Growing evidence suggests SARS-CoV-2 also exacerbates many chronic diseases, including cancers. As mutations on the spike protein (S) emerged as dominant variants that reduce vaccine efficacy, little is known about the relation between SARS-CoV-2 virus variants and cancers. Compared to the SARS-CoV-2 wild-type, the Gamma variant contains two additional NXT/S glycosylation motifs on the S protein. The hyperglycosylated S of Gamma variant is more stable, resulting in more significant epithelial-mesenchymal transition (EMT) potential. SARS-CoV-2 infection promoted NF-κB signaling activation and p65 nuclear translocation, inducing Snail expression. Pharmacologic inhibition of NF-κB activity by nature food compound, I3C suppressed viral replication and Gamma variant-mediated breast cancer metastasis, indicating that NF-κB inhibition can reduce chronic disease in COVID-19 patients. Our study revealed that the Gamma variant of SARS-CoV-2 activates NF-κB and, in turn, triggers the pro-survival function for cancer progression.

7.
BMC Cancer ; 19(1): 176, 2019 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-30808421

RESUMO

BACKGROUND: Zoledronic acid (ZA), a nitrogen-containing bisphosphonate, inhibits osteoclastogenesis. Emerging evidence suggests that ZA has anti-tumor and anti-metastatic properties for breast cancer cells. In a mouse model of ZA-related osteonecrosis of the jaw, ZA administration was found to suppress regulatory T-cells (Tregs) function. Our previous reports also demonstrated ZA acted as an immune modulator to block Tregs. Manipulation of Tregs represents a new strategy for cancer treatment. However, the relationship among ZA, Tregs, and cancer cells remains unclear. In this study, we investigated the effects of ZA on the interaction of breast cancer cells and Tregs. METHODS: The anti-tumor effect of ZA on triple negative breast cancer cell lines were validated by XTT, wound healing and apoptosis analysis. A flow cytometry-based assay was used to analyze the immunosuppressive effect of Tregs treated with media conditioned by breast cancer cells, and a transwell assay was used to evaluate the chemotactic migration of Tregs. Differential gene expression profile on MDA-MB-231 treated with ZA (25 µM) was analyzed by. microarrays to describe the molecular basis of actions of ZA for possible direct anti-tumor effects. Enzyme-linked immunosorbent assays and quantitative real-time PCR were used to investigate the effect of ZA on the expression of cytokines/factors by breast cancer cells. RESULTS: ZA was found to inhibit the proliferation and migration of breast cancer cells. Media conditioned by the MDA-MB-231 cells promoted the expansion, chemotactic migration, and immunosuppressive activity of Tregs, and these effects were attenuated in a dose-dependent manner by ZA treatment, and the attenuation was due to reduced expression of selected breast cancer cell factors (CCL2, CCL5, and IDO). CONCLUSIONS: ZA can significantly affect the interaction between breast cancer cells and Tregs. Our findings indicate that ZA is a potential therapeutic agent that can be used to reduce cancer aggressiveness by abolishing the supportive role of Tregs.


Assuntos
Fatores Imunológicos/farmacologia , Linfócitos T Reguladores/imunologia , Neoplasias de Mama Triplo Negativas/tratamento farmacológico , Ácido Zoledrônico/farmacologia , Comunicação Celular , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células , Quimiocina CCL2/metabolismo , Quimiocina CCL5/metabolismo , Feminino , Perfilação da Expressão Gênica , Humanos , Indolamina-Pirrol 2,3,-Dioxigenase/metabolismo , Linfócitos T Reguladores/efeitos dos fármacos , Neoplasias de Mama Triplo Negativas/imunologia , Microambiente Tumoral
8.
BMC Immunol ; 17(1): 45, 2016 11 25.
Artigo em Inglês | MEDLINE | ID: mdl-27887569

RESUMO

BACKGROUND: CD4+CD25+ regulatory T (Treg) cells suppress tumor immunity by inhibiting immune cells. Manipulation of Treg cells represents a new strategy for cancer treatment. Zoledronic acid (ZA), a nitrogen-containing bisphosphonate, inhibits the expression of receptor activator of nuclear factor kappa-B ligand (RANKL) on osteoblasts to inhibit osteoclastogenesis. In a mouse model of bisphosphonate-related osteonecrosis of the jaw, administration of ZA suppressed Treg-cell activity and activated inflammatory Th17 cells. However, the interaction between ZA and Treg cells remained unclear. This study investigated the immune modulation of Treg cells by ZA. METHODS: Flow cytometry was used to analyze the phenotypic and immunosuppressive characteristics of Treg cells treated with ZA. Chemotactic migration was evaluated using transwell assays. Quantitative real-time PCR (qRT-PCR) was used to investigate the effect of ZA on the expression of suppressive molecules by Treg cells. RESULTS: Proliferation of isolated Treg cells in culture was inhibited by ZA, although ZA did not induce apoptosis. qRT-PCR and flow cytometry showed that ZA significantly downregulated the expression of CCR4, CTLA4, PD-1 and RANKL on Treg cells. Chemotactic migration and immunosuppressive functions were also significantly attenuated in Treg cells pretreated with ZA, and these effects were dose-dependent. Co-culture with Treg cells significantly increased the migration rate of breast cancer cells, while pretreatment of Treg cells with ZA attenuated this effect. CONCLUSIONS: Our findings demonstrated that ZA acted as an immune modulator by significantly inhibiting the expansion, migration, immunosuppressive function and pro-metastatic ability of Treg cells. Immunomodulation of Treg cells by ZA represents a new strategy for cancer therapy.


Assuntos
Neoplasias da Mama/imunologia , Vacinas Anticâncer/imunologia , Difosfonatos/farmacologia , Imidazóis/farmacologia , Fatores Imunológicos/farmacologia , Imunoterapia/métodos , Osteogênese , Linfócitos T Reguladores/imunologia , Células Th17/imunologia , Neoplasias da Mama/tratamento farmacológico , Antígenos CD4/metabolismo , Movimento Celular , Células Cultivadas , Técnicas de Cocultura , Difosfonatos/uso terapêutico , Feminino , Humanos , Imidazóis/uso terapêutico , Fatores Imunológicos/uso terapêutico , Imunoterapia/tendências , Subunidade alfa de Receptor de Interleucina-2/metabolismo , Ativação Linfocitária , NF-kappa B/metabolismo , Ligante RANK/metabolismo , Transdução de Sinais , Linfócitos T Reguladores/efeitos dos fármacos , Ácido Zoledrônico
9.
Biomed Res Int ; 2016: 5173898, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27563668

RESUMO

Aortic dissection is a life-threatening condition. However, the use of medication to treat it remains unclear in our population, particularly in patients with a type B aortic dissection (TBAD) who do not receive surgery. This retrospective cohort study evaluated antihypertensive prescription patterns and outcomes in patients with nonsurgical TBAD. We reviewed the hospital records of patients with TBAD at a medical center in Taiwan from January 2008 to June 2013 to assess the baseline information, prescribing pattern, event rate, and clinical effectiveness of different antihypertensive treatment strategies. A Cox proportional hazards model was used to estimate outcomes in different antihypertensive strategies. The primary endpoints were all-cause mortality and hospital admission for an aortic dissection. We included 106 patients with a mean follow-up period of 2.75 years. The most common comorbidity was hypertension followed by dyslipidemia and diabetes mellitus. Study endpoints mostly occurred within 6 months after the index date. Over 80% of patients received dual or triple antihypertensive strategies. Patients treated with different treatment strategies did not have a significantly increased risk of a primary outcome compared with those treated with a monotherapy. We found no significant difference in the primary outcome following the use of different antihypertensive medication regimes.


Assuntos
Anti-Hipertensivos/administração & dosagem , Aneurisma da Aorta Torácica/tratamento farmacológico , Hipertensão/tratamento farmacológico , Idoso , Aneurisma da Aorta Torácica/complicações , Aneurisma da Aorta Torácica/mortalidade , Aneurisma da Aorta Torácica/patologia , Diabetes Mellitus/mortalidade , Diabetes Mellitus/patologia , Dislipidemias/mortalidade , Dislipidemias/patologia , Feminino , Registros Hospitalares , Humanos , Hipertensão/complicações , Hipertensão/mortalidade , Hipertensão/patologia , Masculino , Pessoa de Meia-Idade , Padrões de Prática Médica , Estudos Retrospectivos , Taiwan , Resultado do Tratamento
10.
Theriogenology ; 85(3): 483-494.e8, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26462659

RESUMO

Acute heat stress severely impacts poultry production. The hypothalamus acts as a crucial center to regulate body temperature, detect temperature changes, and modulate the autonomic nervous system and endocrine loop for heat retention and dissipation. The purpose of this study was to investigate global gene expression in the hypothalamus of broiler-type B strain Taiwan country chickens after acute heat stress. Twelve 30-week-old hens were allocated to four groups. Three heat-stressed groups were subjected to acute heat stress at 38 °C for 2 hours without recovery (H2R0), with 2 hours of recovery (H2R2), and with 6 hours of recovery (H2R6). The control hens were maintained at 25 °C. At the end, hypothalamus samples were collected for gene expression analysis. The results showed that 24, 11, and 25 genes were upregulated and 41, 15, and 42 genes were downregulated in H2R0, H2R2, and H2R6 treatments, respectively. The expressions of gonadotropin-releasing hormone 1 (GNRH1), heat shock 27-kDa protein 1 (HSPB1), neuropeptide Y (NPY), and heat shock protein 25 (HSP25) were upregulated at all recovery times after heat exposure. Conversely, the expression of TPH2 was downregulated at all recovery times. A gene ontology analysis showed that most of the differentially expressed genes were involved in biological processes including cellular processes, metabolic processes, localization, multicellular organismal processes, developmental processes, and biological regulation. A functional annotation analysis showed that the differentially expressed genes were related to the gene networks of responses to stress and reproductive functions. These differentially expressed genes might be essential and unique key factors in the heat stress response of the hypothalamus in chickens.


Assuntos
Galinhas/metabolismo , Perfilação da Expressão Gênica/veterinária , Hipotálamo/metabolismo , Animais , Regulação para Baixo/fisiologia , Feminino , Hormônio Liberador de Gonadotropina/genética , Proteínas de Choque Térmico HSP27/genética , Resposta ao Choque Térmico/genética , Temperatura Alta , Hipotálamo/química , Neuropeptídeo Y/genética , RNA Mensageiro/análise , Taiwan , Triptofano Hidroxilase/genética , Regulação para Cima/fisiologia
11.
PLoS One ; 10(11): e0143418, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26587838

RESUMO

This study investigated global gene expression in the small yellow follicles (6-8 mm diameter) of broiler-type B strain Taiwan country chickens (TCCs) in response to acute heat stress. Twelve 30-wk-old TCC hens were divided into four groups: control hens maintained at 25°C and hens subjected to 38°C acute heat stress for 2 h without recovery (H2R0), with 2-h recovery (H2R2), and with 6-h recovery (H2R6). Small yellow follicles were collected for RNA isolation and microarray analysis at the end of each time point. Results showed that 69, 51, and 76 genes were upregulated and 58, 15, 56 genes were downregulated after heat treatment of H2R0, H2R2, and H2R6, respectively, using a cutoff value of two-fold or higher. Gene ontology analysis revealed that these differentially expressed genes are associated with the biological processes of cell communication, developmental process, protein metabolic process, immune system process, and response to stimuli. Upregulation of heat shock protein 25, interleukin 6, metallopeptidase 1, and metalloproteinase 13, and downregulation of type II alpha 1 collagen, discoidin domain receptor tyrosine kinase 2, and Kruppel-like factor 2 suggested that acute heat stress induces proteolytic disintegration of the structural matrix and inflamed damage and adaptive responses of gene expression in the follicle cells. These suggestions were validated through gene expression, using quantitative real-time polymerase chain reaction. Functional annotation clarified that interleukin 6-related pathways play a critical role in regulating acute heat stress responses in the small yellow follicles of TCC hens.


Assuntos
Galinhas/fisiologia , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Resposta ao Choque Térmico/genética , Temperatura Alta , Folículo Ovariano/metabolismo , Animais , Temperatura Corporal , Primers do DNA , Feminino , Interleucina-6/metabolismo , Análise de Sequência com Séries de Oligonucleotídeos , Folículo Ovariano/patologia , RNA/análise , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Estresse Fisiológico , Taiwan , Regulação para Cima
12.
Sensors (Basel) ; 15(4): 7084-95, 2015 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-25811223

RESUMO

The parts-per-billion-level nitric oxide (NO) gas sensing capability of a copper-ion-doped polyaniline/tungsten oxide nanocomposite (Cu(2+)/PANI/WO3) film coated on a Rayleigh surface acoustic wave device was investigated. The sensor developed in this study was sensitive to NO gas at room temperature in dry nitrogen. The surface morphology, dopant distribution, and electric properties were characterized using scanning electron microscopy, energy-dispersive X-ray spectroscopy mapping, and Hall effect measurements, respectively. The Cu(2+)/PANI/WO3 film exhibited high NO gas sensitivity and selectivity as well as long-term stability. At 1 ppb of NO, a signal with a frequency shift of 4.3 ppm and a signal-to-noise ratio of 17 was observed. The sensor exhibited distinct selectivity toward NO gas with no substantial response to O2, NH3 and CO2 gases.


Assuntos
Compostos de Anilina/química , Cobre/química , Nanocompostos/química , Óxido Nítrico/química , Óxidos/química , Tungstênio/química
13.
Biosens Bioelectron ; 33(1): 120-7, 2012 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-22236778

RESUMO

A new highly catalytic and intensely sensitive amperometric sensor based on PtM (where M=Pd, Ir) bimetallic nanoparticles (NPs) for the rapid and accurate estimation of hydrogen peroxide (H(2)O(2)) by electrooxidation in physiological conditions is reported. PtPd and PtIr NPs-decorated multiwalled carbon nanotube nanocatalysts (PtM/MWCNTs) were prepared by a modified Watanabe method, and were characterized by XRD, TEM, ICP, and XAS. The sensors were constructed by immobilizing PtM/MWCNTs nanocatalysts in a Nafion film on a glassy carbon electrode. Both PtPd/MWCNTs and PtIr/MWCNTs assemblies catalyzed the electrochemical oxidation of H(2)O(2). Cyclic voltammetry characterization measurements revealed that both the PtM (M=Pd, Ir)/MWCNTs/GCE possessed similar electrochemical surface areas (∼0.55 cm(2)), and electron transfer rate constants (∼1.23 × 10(-3)cms(-1)); however, the PtPd sensor showed a better performance in H(2)O(2) sensing than did the PtIr counterpart. Explanations were sought from XAS measurements to explain the reasons for differences in sensor activity. When applied to the electrochemical detection of H(2)O(2), the PtPd/MWCNTs/GC electrode exhibited a low detection limit of 1.2 µM with a wide linear range of 2.5-125 µM (R(2)=0.9996). A low working potential (0V (SCE)), fast amperometric response (<5s), and high sensitivity (414.8 µA mM(-1)cm(-2)) were achieved at the PtPd/MWCNTs/GC electrode. In addition, the PtPd/MWCNTs nanocatalyst sensor electrode also exhibited excellent reproducibility and stability. Along with these attractive features, the sensor electrode also displayed very high specificity to H(2)O(2) with complete elimination of interference from UA, AA, AAP and glucose.


Assuntos
Técnicas Biossensoriais/métodos , Técnicas Eletroquímicas/métodos , Peróxido de Hidrogênio/análise , Nanopartículas Metálicas/química , Nanotubos de Carbono/química , Reprodutibilidade dos Testes
14.
Fertil Steril ; 95(8): 2520-3.e1-2, 2011 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-21575945

RESUMO

We tested differences in serum apelin levels between women with polycystic ovary syndrome (PCOS) and those with a healthy regular menstrual cycle, finding that apelin levels were higher in normal women and that apelin was positively correlated with apolipoprotein A levels.


Assuntos
Peptídeos e Proteínas de Sinalização Intercelular/sangue , Síndrome do Ovário Policístico/sangue , Adulto , Apelina , Apolipoproteínas A/sangue , Biomarcadores/sangue , Estudos de Casos e Controles , Regulação para Baixo , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Taiwan , Adulto Jovem
15.
Sensors (Basel) ; 10(3): 1670-8, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-22294893

RESUMO

A thick-film electrochemical sensor with an iridium-carbon working electrode was used for determining polyphenols and their antioxidant capacity in white wine. Caffeic acid was used as a model species because it has the ability to produce the highest oxidation current. The correlation coefficient of 0.9975 was obtained between sensor response and caffeic acid content. The total phenolic content (TPC) and scavenging activity on 1,1-diphenyl-2-pycrylhydrazyl (DPPH·) radical were also found to be strongly correlated with the concentration of caffeic acid, with a correlation coefficient of 0.9823 and 0.9958, respectively. The sensor prototype was proven to be a simple, efficient and cost effective device to evaluate the antioxidant capacity of substances.


Assuntos
Antioxidantes/análise , Técnicas Eletroquímicas/instrumentação , Polifenóis/análise , Vinho/análise , Antioxidantes/metabolismo , Compostos de Bifenilo/química , Compostos de Bifenilo/metabolismo , Ácidos Cafeicos/análise , Ácidos Cafeicos/metabolismo , Técnicas Eletroquímicas/métodos , Desenho de Equipamento , Picratos/química , Picratos/metabolismo , Polifenóis/metabolismo
16.
Biosens Bioelectron ; 22(4): 501-5, 2006 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-16920349

RESUMO

A portable and cost-effective technique to measure the dimethyl ether (DME) concentrations has been developed. It is based on an electrochemical principle measuring the oxidation current of DME at an applied potential of +0.2V versus a Ag/AgCl reference electrode. Thick-film printing technique is used for the fabrication of this DME sensor, and platinum nanoparticles in the crystallite size of 5.5 nm are used for the modification of the working electrode surface. This modification enhances the sensor performance significantly leading to a higher sensitivity of the sensor comparing to bare platinum electrode. Evaluation and characterization of this sensor are carried out over the DME concentration range of 0-7% (v/v), and a linear relationship between sensor outputs and the DME concentrations with an average R(2) of 0.996 exists. The reproducibility of the sensor is also very good. This electrochemically based DME sensor fabricated by thick-film screen printing technique and using the platinum nanoparticles to enhance its performance will be valuable and practical for the estimation of the airway mucosal blood flow.


Assuntos
Técnicas Biossensoriais/instrumentação , Gasometria/instrumentação , Éteres Metílicos/análise , Microeletrodos , Nanopartículas/química , Platina/química , Técnicas Biossensoriais/métodos , Gasometria/métodos , Materiais Revestidos Biocompatíveis/química , Desenho de Equipamento , Análise de Falha de Equipamento , Nanopartículas/ultraestrutura , Tamanho da Partícula , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Propriedades de Superfície
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