Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 28
Filtrar
Mais filtros

Bases de dados
Tipo de documento
Intervalo de ano de publicação
3.
Anal Chem ; 90(10): 6006-6011, 2018 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-29685039

RESUMO

Herein, we developed an automatic electrical bacterial growth sensor (EBGS) based on a multichannel capacitively coupled contactless conductivity detector (C4D). With the use of the EBGS, up to eight culture samples of E. coli in disposable tubes were online monitored simultaneously in a noninvasive manner. Growth curves with high resolution (on the order of a time scale of seconds) were generated by plotting normalized apparent conductivity value against incubation time. The characteristic data of E. coli growth (e.g., growth rate) obtained here were more accurate than those obtained with optical density and contact conductivity methods. And the correlation coefficient of the regression line ( r) for quantitative determination of viable bacteria was 0.9977. Moreover, it also could be used for other tasks, such as the investigation of toxic/stress effects from chemicals and antimicrobial susceptibility testing. All of these performances required neither auxiliary devices nor additional chemicals and biomaterials. Taken together, this strategy has the advantages of simplicity, accuracy, reproducibility, affordability, versatility, and miniaturization, liberating the users greatly from financial and labor costs.


Assuntos
Condutividade Elétrica , Eletrônica , Escherichia coli/crescimento & desenvolvimento , Sistemas On-Line , Automação , Eletrônica/economia , Sistemas On-Line/economia , Análise de Regressão , Temperatura
6.
PLoS One ; 10(8): e0136939, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26317999

RESUMO

Electrically small antennas (ESAs) are becoming one of the key components in the compact wireless devices for telecommunications, defence, and aerospace systems, especially for the spherical one whose geometric layout is more closely approaching Chu's limit, thus yielding significant bandwidth improvements relative to the linear and planar counterparts. Yet broad applications of the volumetric ESAs are still hindered since the low cost fabrication has remained a tremendous challenge. Here we report a state-of-the-art technology to transfer electrically conductive composites (ECCs) from a planar mould to a volumetric thermoplastic substrate by using pad-printing technology without pattern distortion, benefit from the excellent properties of the ECCs as well as the printing-calibration method that we developed. The antenna samples prepared in this way meet the stringent requirement of an ESA (ka is as low as 0.32 and the antenna efficiency is as high as 57%), suggesting that volumetric electronic components i.e. the antennas can be produced in such a simple, green, and cost-effective way. This work can be of interest for the development of studies on green and high performance wireless communication devices.


Assuntos
Eletrônica/métodos , Tecnologia sem Fio/instrumentação , Condutividade Elétrica , Eletrônica/economia , Eletrônica/instrumentação , Desenho de Equipamento , Propriedades de Superfície , Tecnologia sem Fio/economia
7.
Seizure ; 26: 49-55, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25799902

RESUMO

PURPOSE: This study used an electronic practice management software in daily routine to gather long-term disease and cost-of-illness (COI) data in patients with epilepsy in Germany. METHODS: Data on socio-economic status, course of epilepsy as well as direct and indirect costs were recorded using practice software-based questionnaires. RESULTS: In 2011 we enrolled 359 patients (170 male (47.4%); mean age 50.5±20.7 years) in six neurological practices. The majority of patients had been in long-term seizure remission for more than one year (n=200, 55.7%) and in more than two-thirds the anti-epileptic drug (AED) monotherapy (n=248, 69.1%) was used. Levetiracetam (31%), lamotrigine (26%) and valproate (24%) were the drugs prescribed most frequently. Total annual direct costs amounted to €1698 per patient with anticonvulsants (59.9% of total direct costs) and hospitalization (30.0%) as the main cost factors. Of the patients enrolled 252 (70.2%) were of working age and indirect annual costs due to absenteeism amounted to €745 per patient. Potential cost-driving factors were seizure frequency and a recent diagnosis of epilepsy associated with higher costs. Anticonvulsant treatment in patients aged 65 years and older was associated with lower drug costs due to prescription of older AEDs. CONCLUSION: We were able to demonstrate that electronic practice management software can easily be used to perform long-term health economic evaluations with a bottom-up approach. The combination of both physician- and patient-based electronic databases will facilitate performing less expensive studies, but at the same time simplify large, prospective and multicentre clinical trials.


Assuntos
Efeitos Psicossociais da Doença , Gerenciamento Clínico , Eletrônica/economia , Epilepsia/economia , Epilepsia/terapia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Anticonvulsivantes/economia , Anticonvulsivantes/uso terapêutico , Análise Custo-Benefício , Prescrições de Medicamentos/economia , Prescrições de Medicamentos/estatística & dados numéricos , Eletrônica/métodos , Feminino , Alemanha , Humanos , Masculino , Pessoa de Meia-Idade , Software , Adulto Jovem
9.
J Clin Epidemiol ; 67(12): 1358-63, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25135245

RESUMO

OBJECTIVES: Existing electronic data capture options are often financially unfeasible in resource-poor settings or difficult to support technically in the field. To help facilitate large-scale multicenter studies in sub-Saharan Africa, the African Partnership for Chronic Disease Research (APCDR) has developed an open-source electronic questionnaire (EQ). STUDY DESIGN AND SETTING: To assess its relative validity, we compared the EQ against traditional pen-and-paper methods using 200 randomized interviews conducted in an ongoing type 2 diabetes case-control study in South Africa. RESULTS: During its 3-month validation, the EQ had a lower frequency of errors (EQ, 0.17 errors per 100 questions; paper, 0.73 errors per 100 questions; P-value ≤0.001), and a lower monetary cost per correctly entered question, compared with the pen-and-paper method. We found no marked difference in the average duration of the interview between methods (EQ, 5.4 minutes; paper, 5.6 minutes). CONCLUSION: This validation study suggests that the EQ may offer increased accuracy, similar interview duration, and increased cost-effectiveness compared with paper-based data collection methods. The APCDR EQ software is freely available (https://github.com/apcdr/questionnaire).


Assuntos
Coleta de Dados/métodos , Eletrônica , Papel , Inquéritos e Questionários , África , Análise Custo-Benefício , Coleta de Dados/economia , Eletrônica/economia , Humanos , Reprodutibilidade dos Testes , Inquéritos e Questionários/economia
10.
J Health Econ ; 36: 33-46, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24732386

RESUMO

Underage drinkers often use false identification to purchase alcohol or gain access into bars. In recent years, several states have introduced laws that provide incentives to retailers and bar owners who use electronic scanners to ensure that the customer is 21 years or older and uses a valid identification to purchase alcohol. This paper is the first to investigate the effects of these laws using confidential data from the National Longitudinal Survey of Youth, 1997 Cohort (NLSY97). Using a difference-in-differences methodology, I find that the false ID laws with scanner provision significantly reduce underage drinking, including up to a 0.22 drink decrease in the average number of drinks consumed by underage youth per day. This effect is observed particularly in the short-run and more pronounced for non-college students and those who are relatively younger. These results are also robust under alternative model specifications. The findings of this paper highlight the importance of false ID laws in reducing alcohol consumption among underage youth.


Assuntos
Comportamento do Adolescente , Consumo de Bebidas Alcoólicas/prevenção & controle , Bebidas Alcoólicas/provisão & distribuição , Consumo Excessivo de Bebidas Alcoólicas/prevenção & controle , Adolescente , Distribuição por Idade , Consumo de Bebidas Alcoólicas/epidemiologia , Consumo de Bebidas Alcoólicas/legislação & jurisprudência , Bebidas Alcoólicas/economia , Consumo Excessivo de Bebidas Alcoólicas/epidemiologia , Consumo Excessivo de Bebidas Alcoólicas/legislação & jurisprudência , Estudos de Coortes , Comércio/economia , Comércio/legislação & jurisprudência , Comércio/tendências , Eletrônica/economia , Eletrônica/legislação & jurisprudência , Eletrônica/tendências , Feminino , Humanos , Estudos Longitudinais , Masculino , Modelos Econométricos , Assunção de Riscos , Transtornos Relacionados ao Uso de Substâncias/epidemiologia , Transtornos Relacionados ao Uso de Substâncias/prevenção & controle , Tecnologia/economia , Tecnologia/legislação & jurisprudência , Tecnologia/tendências , Estados Unidos/epidemiologia , Adulto Jovem
11.
Sensors (Basel) ; 13(6): 7872-83, 2013 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-23783738

RESUMO

Chlorophyll a fluorometry has long been used as a method to study phytoplankton in the ocean. In situ fluorometry is used frequently in oceanography to provide depth-resolved estimates of phytoplankton biomass. However, the high price of commercially manufactured in situ fluorometers has made them unavailable to some individuals and institutions. Presented here is an investigation into building an in situ fluorometer using low cost electronics. The goal was to construct an easily reproducible in situ fluorometer from simple and widely available electronic components. The simplicity and modest cost of the sensor makes it valuable to students and professionals alike. Open source sharing of architecture and software will allow students to reconstruct and customize the sensor on a small budget. Research applications that require numerous in situ fluorometers or expendable fluorometers can also benefit from this study. The sensor costs US$150.00 and can be constructed with little to no previous experience. The sensor uses a blue LED to excite chlorophyll a and measures fluorescence using a silicon photodiode. The sensor is controlled by an Arduino microcontroller that also serves as a data logger.


Assuntos
Clorofila/análise , Fluorometria , Fitoplâncton/metabolismo , Calibragem , Clorofila/normas , Clorofila A , Eletrônica/economia , Fluorometria/normas , Software
12.
PLoS One ; 7(11): e49365, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23185319

RESUMO

3D printing technology can produce complex objects directly from computer aided digital designs. The technology has traditionally been used by large companies to produce fit and form concept prototypes ('rapid prototyping') before production. In recent years however there has been a move to adopt the technology as full-scale manufacturing solution. The advent of low-cost, desktop 3D printers such as the RepRap and Fab@Home has meant a wider user base are now able to have access to desktop manufacturing platforms enabling them to produce highly customised products for personal use and sale. This uptake in usage has been coupled with a demand for printing technology and materials able to print functional elements such as electronic sensors. Here we present formulation of a simple conductive thermoplastic composite we term 'carbomorph' and demonstrate how it can be used in an unmodified low-cost 3D printer to print electronic sensors able to sense mechanical flexing and capacitance changes. We show how this capability can be used to produce custom sensing devices and user interface devices along with printed objects with embedded sensing capability. This advance in low-cost 3D printing with offer a new paradigm in the 3D printing field with printed sensors and electronics embedded inside 3D printed objects in a single build process without requiring complex or expensive materials incorporating additives such as carbon nanotubes.


Assuntos
Condutividade Elétrica , Eletrônica/economia , Eletrônica/instrumentação , Plásticos/química , Impressão/economia , Impressão/instrumentação , Custos e Análise de Custo
14.
Environ Sci Technol ; 45(10): 4540-7, 2011 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-21513286

RESUMO

Remanufactured products that can substitute for new products are generally claimed to save energy. These claims are made from studies that look mainly at the differences in materials production and manufacturing. However, when the use phase is included, the situation can change radically. In this Article, 25 case studies for eight different product categories were studied, including: (1) furniture, (2) clothing, (3) computers, (4) electric motors, (5) tires, (6) appliances, (7) engines, and (8) toner cartridges. For most of these products, the use phase energy dominates that for materials production and manufacturing combined. As a result, small changes in use phase efficiency can overwhelm the claimed savings from materials production and manufacturing. These use phase energy changes are primarily due to efficiency improvements in new products, and efficiency degradation in remanufactured products. For those products with no, or an unchanging, use phase energy requirement, remanufacturing can save energy. For the 25 cases, we found that 8 cases clearly saved energy, 6 did not, and 11 were too close to call. In some cases, we could examine how the energy savings potential of remanufacturing has changed over time. Specifically, during times of significant improvements in energy efficiency, remanufacturing would often not save energy. A general design trend seems to be to add power to a previously unpowered product, and then to improve on the energy efficiency of the product over time. These trends tend to undermine the energy savings potential of remanufacturing.


Assuntos
Conservação de Recursos Energéticos/métodos , Eletrônica/estatística & dados numéricos , Utensílios Domésticos/estatística & dados numéricos , Manufaturas/estatística & dados numéricos , Resíduo Eletrônico/análise , Resíduo Eletrônico/estatística & dados numéricos , Eletrônica/economia , Utensílios Domésticos/economia , Indústrias/economia , Indústrias/métodos , Manufaturas/análise , Manufaturas/economia
16.
J Neurosci Methods ; 187(1): 105-13, 2010 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-20036283

RESUMO

Auditory steady state responses (ASSR) are a current research focus because of their potential use as a diagnostic tool. Research platforms are required to test user defined stimuli and algorithms for the analysis of electrophysiologic responses. Commercially available ASSR devices are not adequately flexible. To enable a larger group of scientists to pursue ASSR research, we introduce a cost-efficient and flexible ASSR setup. ASSR recording and online analysis software in Matlab (The Mathworks, Inc.) was developed for a standard PC equipped with an external professional sound card, audiometric headphones, and an EEG biosignal preamplifier.


Assuntos
Percepção Auditiva/fisiologia , Encéfalo/fisiologia , Eletroencefalografia/instrumentação , Eletroencefalografia/métodos , Potenciais Evocados Auditivos , Software , Algoritmos , Computadores , Eletroencefalografia/economia , Eletrônica/economia , Eletrônica/instrumentação , Eletrônica/métodos , Análise de Fourier , Humanos , Processamento de Sinais Assistido por Computador , Design de Software , Interface Usuário-Computador
18.
Environ Sci Technol ; 42(18): 6800-8, 2008 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-18853792

RESUMO

A framework for evaluating the economic performance of a recycling system is proposed, and data from four electronics recycling systems in North America (Alberta, California, Maine, and Maryland) that use different operating models are used as a preliminary test of the framework. The framework is built around a hierarchy of descriptors that clarify the function of the system components under consideration and the activities, cash flow elements, and resources within those functions; costs are incurred by specific stakeholders. Data from each system on fee and mass collection amounts and collection, processing, and management costs are used to create a matrix of several net costs for stakeholders within each system. Although all four systems are relatively new, thereby making data collection a challenge, some preliminary insights can be gleaned from comparing the systems. Processing costs vary significantly in the four systems, with Alberta and California having the highest reimbursement rates for processing. Alberta and California also have relatively high system management costs, but processors are generally quite satisfied with the systems. Maine has an additional cost for consolidation that is an implicit management cost because of the need to count incoming products by manufacturer.


Assuntos
Conservação dos Recursos Naturais/economia , Eletrônica/economia , Estudos de Avaliação como Assunto , Eliminação de Resíduos/economia , Alberta , California , Maine , América do Norte
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA