Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 12.468
Filtrar
1.
J Med Internet Res ; 22(5): e19437, 2020 05 26.
Artigo em Inglês | MEDLINE | ID: mdl-32412416

RESUMO

BACKGROUND: In early 2020, coronavirus disease (COVID-19) emerged and spread by community and nosocomial transmission. Effective contact tracing of potentially exposed health care workers is crucial for the prevention and control of infectious disease outbreaks in the health care setting. OBJECTIVE: This study aimed to evaluate the comparative effectiveness of contact tracing during the COVID-19 pandemic through the real-time locating system (RTLS) and review of the electronic medical record (EMR) at the designated hospital for COVID-19 response in Singapore. METHODS: Over a 2-day study period, all admitted patients with COVID-19, their ward locations, and the health care workers rostered to each ward were identified to determine the total number of potential contacts between patients with COVID-19 and health care workers. The numbers of staff-patient contacts determined by EMR reviews, RTLS-based contact tracing, and a combination of both methods were evaluated. The use of EMR-based and RTLS-based contact tracing methods was further validated by comparing their sensitivity and specificity against self-reported staff-patient contacts by health care workers. RESULTS: Of 796 potential staff-patient contacts (between 17 patients and 162 staff members), 104 (13.1%) were identified by both the RTLS and EMR, 54 (6.8%) by the RTLS alone, and 99 (12.4%) by the EMR alone; 539 (67.7%) were not identified through either method. Compared to self-reported contacts, EMR reviews had a sensitivity of 47.2% and a specificity of 77.9%, while the RTLS had a sensitivity of 72.2% and a specificity of 87.7%. The highest sensitivity was obtained by including all contacts identified by either the RTLS or the EMR (sensitivity 77.8%, specificity 73.4%). CONCLUSIONS: RTLS-based contact tracing showed higher sensitivity and specificity than EMR review. Integration of both methods provided the best performance for rapid contact tracing, although technical adjustments to the RTLS and increasing user compliance with wearing of RTLS tags remain necessary.


Assuntos
Betacoronavirus , Busca de Comunicante , Infecções por Coronavirus/epidemiologia , Pessoal de Saúde/estatística & dados numéricos , Pneumonia Viral/epidemiologia , Sistemas Computacionais , Infecções por Coronavirus/prevenção & controle , Surtos de Doenças/prevenção & controle , Registros Eletrônicos de Saúde , Feminino , Humanos , Pandemias/prevenção & controle , Pneumonia Viral/prevenção & controle , Singapura
2.
Tohoku J Exp Med ; 251(1): 47-49, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32461502

RESUMO

The reported number of new cases underestimates the real spread of COVID-19 pandemic because of non-tested asymptomatic people and limited global access to reliable diagnostic tests. In this context, COVID-19 mortality with confirmed diagnosis becomes an attractive source of information to be included in the analysis of perspectives and proposals. Objective data are required to calculate the capacity of resources provided by health systems. New strategies are needed to stabilize or minimize the mortality surge. However, we will not afford this goal until more alternatives were available. We still need an effective treatment, an affordable vaccine, or a collective achievement of sufficient immunity (reaching up to 70% of the whole population). At any time, the arriving waves of the pandemic are testing the capacity of governments. The health services struggle to keep the plateau in a steady-state below 100 deaths per million inhabitants. Therefore, it is necessary to increase the alternatives and supplies based on the current and near-future expected demands imposed by the number of deaths by COVID-19. Estimating COVID-19 mortality in various scenarios with the gradual release of social constraints will help predict the magnitude of those arriving waves.


Assuntos
Betacoronavirus , Infecções por Coronavirus/mortalidade , Monitoramento Epidemiológico , Mortalidade , Pneumonia Viral/mortalidade , População , Betacoronavirus/patogenicidade , Betacoronavirus/fisiologia , Sistemas Computacionais , Infecções por Coronavirus/epidemiologia , Surtos de Doenças/estatística & dados numéricos , Sistemas de Informação Geográfica/organização & administração , Sistemas de Informação Geográfica/normas , Mapeamento Geográfico , Geografia , Recursos em Saúde/organização & administração , Recursos em Saúde/normas , Necessidades e Demandas de Serviços de Saúde , Humanos , Mortalidade/tendências , Pandemias , Pneumonia Viral/epidemiologia , Fatores de Tempo
4.
PLoS One ; 15(4): e0230946, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32243469

RESUMO

Spatial conservation prioritization concerns trade-offs between marine conservation and resource exploitation. This approach has been increasingly used to devise spatial management strategies for fisheries because of its simplicity in the optimization model and less data requirement compared to complex dynamic models. However, most of the prioritization is based on static models or algorithms; whose solutions need to be evaluated in a dynamic approach, considering the high uncertainty and opportunity costs associated with their implementation. We developed a framework that integrates species distribution models, spatial conservation prioritization tools and a general grid-based dynamic model (Grid-DM) to support evaluation of ecological and economic trade-offs of candidate conservation plans. The Grid-DM is spatially explicit and has a tactical management focus on single species. We applied the Grid-DM to small yellow croaker (Larimichthys polyactis) in Haizhou Bay, China and validated its spatial and temporal performances against historical observations. It was linked to a spatial conservation prioritization tool Marxan to illustrate how the model can be used for conservation strategy evaluation. The simulation model demonstrated effectiveness in capturing the spatio-temporal dynamics of the target fishery as well as the socio-ecological effects of conservation measures. We conclude that the model has the capability and flexibility to address various forms of uncertainties, simulate the dynamics of a targeted fishery, and to evaluate biological and socioeconomic impacts of management plans. The modelling platform can further inform scientists and policy makers of management alternatives screening and adaptive conservation planning.


Assuntos
Conservação dos Recursos Naturais/métodos , Perciformes/crescimento & desenvolvimento , Pessoal Administrativo , Algoritmos , Animais , Biodiversidade , China , Sistemas Computacionais , Ecossistema , Pesqueiros
5.
PLoS One ; 15(2): e0229431, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32092113

RESUMO

BACKGROUND: Current guidelines underline the importance of high-quality chest compression during cardiopulmonary resuscitation (CPR), to improve outcomes. Contrary to this many studies show that chest compression is often carried out poorly in clinical practice, and long interruptions in compression are observed. This prospective cohort study aimed to analyse whether chest compression quality changes when a real-time feedback system is used to provide simultaneous audiovisual feedback on chest compression quality. For this purpose, pauses in compression, compression frequency and compression depth were compared. METHODS: The study included 292 out-of-hospital cardiac arrests in three consecutive study groups: first group, conventional resuscitation (no-sensor CPR); second group, using a feedback sensor to collect compression depth data without real-time feedback (sensor-only CPR); and third group, with real-time feedback on compression quality (sensor-feedback CPR). Pauses and frequency were analysed using compression artefacts on electrocardiography, and compression depth was measured using the feedback sensor. With this data, various parameters were determined in order to be able to compare the chest compression quality between the three consecutive groups. RESULTS: The compression fraction increased with sensor-only CPR (group 2) in comparison with no-sensor CPR (group 1) (80.1% vs. 87.49%; P < 0.001), but there were no further differences belonging compression fraction after activation of sensor-feedback CPR (group 3) (P = 1.00). Compression frequency declined over the three study groups, reaching the guideline recommendations (127.81 comp/min vs. 122.96 comp/min, P = 0.02 vs. 119.15 comp/min, P = 0.008) after activation of sensor-feedback CPR (group 3). Mean compression depth only changed minimally with sensor-feedback (52.49 mm vs. 54.66 mm; P = 0.16), but the fraction of compressions with sufficient depth (at least 5 cm) and compressions within the recommended 5-6 cm increased significantly with sensor-feedback CPR (56.90% vs. 71.03%; P = 0.003 and 28.74% vs. 43.97%; P < 0.001). CONCLUSIONS: The real-time feedback system improved chest compression quality regarding pauses in compression and compression frequency and facilitated compliance with the guideline recommendations. Compression depth did not change significantly after activation of the real-time feedback. Even the sole use of a CPR-feedback-sensor ("sensor-only CPR") improved performance regarding pauses in compression and compression frequency, a phenomenon known as the 'Hawthorne effect'. Based on this data real-time feedback systems can be expected to raise the quality level in some parts of chest compression quality. TRIAL REGISTRATION: International Clinical Trials Registry Platform of the World Health Organisation and German Register of Clinical Trials (DRKS00009903), Registered 09 February 2016 (retrospectively registered).


Assuntos
Reanimação Cardiopulmonar/normas , Sistemas Computacionais , Retroalimentação Sensorial , Massagem Cardíaca/normas , Parada Cardíaca Extra-Hospitalar/terapia , Adulto , Idoso , Idoso de 80 Anos ou mais , Reanimação Cardiopulmonar/instrumentação , Reanimação Cardiopulmonar/métodos , Estudos de Coortes , Cardioversão Elétrica , Eletrocardiografia/instrumentação , Eletrocardiografia/métodos , Retroalimentação Sensorial/fisiologia , Feminino , Alemanha , Massagem Cardíaca/instrumentação , Massagem Cardíaca/métodos , Humanos , Masculino , Pessoa de Meia-Idade , Pressão , Melhoria de Qualidade , Tórax , Fatores de Tempo
6.
PLoS One ; 15(2): e0228434, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32027668

RESUMO

The service quality and system dependability of real-time communication networks strongly depends on the analysis of monitored data, to identify concrete problems and their causes. Many of these can be described by either their structural or temporal properties, or a combination of both. As current research is short of approaches sufficiently addressing both properties simultaneously, we propose a new feature space specifically suited for this task, which we analyze for its theoretical properties and its practical relevance. We evaluate its classification performance when used on real-world data sets of structural-temporal mobile communication data, and compare it to the performance achieved of feature representations used in related work. For this purpose we propose a system which allows the automatic detection and prediction of classes of pre-defined sequence behavior, greatly reducing costs caused by the otherwise required manual analysis. With our proposed feature spaces this system achieves a precision of more than 93% at recall values of 100%, with an up to 6.7% higher effective recall than otherwise similarly performing alternatives, notably outperforming alternative deep learning, kernel learning and ensemble learning approaches of related work. Furthermore the supported system calibration allows separating reliable from unreliable predictions more effectively, which is highly relevant for any practical application.


Assuntos
Comunicação , Aprendizado Profundo , Aprendizado de Máquina , Redes Neurais de Computação , Sistemas Computacionais/normas , Confiabilidade dos Dados , Mineração de Dados/métodos , Mineração de Dados/normas , Conjuntos de Dados como Assunto/normas , Humanos , Aplicativos Móveis/normas , Aplicativos Móveis/estatística & dados numéricos , Reprodutibilidade dos Testes , Fatores de Tempo , Estudos de Validação como Assunto
7.
J Surg Oncol ; 121(6): 964-966, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32103507

RESUMO

BACKGROUND: Near-infrared (NIR) fluorescence imaging has recently been introduced to the sentinel lymph node (SLN) mapping because of the benefits of the SLN biopsy, such as providing real-time and high-resolution optical guidance. Methylene blue is available and less expensive as an SLN mapping tracer. Our study aims to identify SLN through the NIR fluorescence imaging system mediated by blue dye. METHODS: Early-stage breast cancer patients were prospectively enrolled. All participants received a subareolar or peritumoral injection of 1 mL methylene blue (MB) before surgery. The MB fluorescence system was set immediately after injection. SLNs were searched and removed under the guidance of fluorescence and blue dye. RESULTS: We identified SLN adequately with the help of real-time lymphography and blue dye. Symbolic lymphatic drainage patterns were also observed. CONCLUSION: NIR fluorescence imaging mediated by blue dye has benefits on the identification of lymph vessels, the location of SLN, and the patterns of breast lymphatic flow.


Assuntos
Neoplasias da Mama/diagnóstico por imagem , Azul de Metileno , Linfonodo Sentinela/diagnóstico por imagem , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Neoplasias da Mama/patologia , Corantes , Sistemas Computacionais , Feminino , Humanos , Linfografia/métodos , Estadiamento de Neoplasias , Linfonodo Sentinela/patologia , Espectrometria de Fluorescência/métodos
8.
PLoS One ; 15(2): e0227805, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32045936

RESUMO

A force sensor system was developed to give real-time visual feedback on a range of force. In a prospective observational cross-section study, twenty-two anaesthesia nurses applied cricoid pressure at a target range of 30-40 Newtons for 60 seconds in three sequential steps on manikin: Group A (step 1 blinded, no sensor), Group B (step 2 blinded sensor), Group C (step 3 sensor feedback). A weighing scale was placed below the manikin. This procedure was repeated once again at least 1 week apart. The feedback system used 3 different colours to indicate the force range achieved as below target, achieve target, above target. Significantly higher proportion of target cricoid pressure was achieved with the use of sensor feedback in Group C; 85.9% (95%CI: 82.7%-88.7%) compared to when blinded from sensor in Group B; 31.3% (95%CI: 27.4-35.4%). Cricoid force achieved blind (Group B) exceeded force achieved with feedback (Group C) by a mean of 8.0 (95%CI: 5.9-10.2, p<0.0001) and 6.2 (95%CI:4.1-8.3, p< 0.0001) Newtons in round 1 and 2 respectively. Weighing scale read lower than corresponding force sensor by a mean of 8.4 Newtons (95% CI: 7.1-9.7, p<0.0001) in group B and 5.8 Newtons (95% CI: 4.5-7.1, p<0.0001) in Group C. Force sensor visual feedback system enabled application of reproducible target cricoid pressure with less variability and has potential value in clinical use. Using weighing scale to quantify and train cricoid pressure requires a review. Understanding the force applied is the first step to make cricoid pressure a safe procedure.


Assuntos
Anestesiologia , Sistemas Computacionais , Manequins , Adulto , Fenômenos Biomecânicos , Cartilagem Cricoide/fisiologia , Estudos Transversais , Retroalimentação , Feminino , Humanos , Estudos Prospectivos
10.
Nat Med ; 26(1): 52-58, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31907460

RESUMO

Intraoperative diagnosis is essential for providing safe and effective care during cancer surgery1. The existing workflow for intraoperative diagnosis based on hematoxylin and eosin staining of processed tissue is time, resource and labor intensive2,3. Moreover, interpretation of intraoperative histologic images is dependent on a contracting, unevenly distributed, pathology workforce4. In the present study, we report a parallel workflow that combines stimulated Raman histology (SRH)5-7, a label-free optical imaging method and deep convolutional neural networks (CNNs) to predict diagnosis at the bedside in near real-time in an automated fashion. Specifically, our CNNs, trained on over 2.5 million SRH images, predict brain tumor diagnosis in the operating room in under 150 s, an order of magnitude faster than conventional techniques (for example, 20-30 min)2. In a multicenter, prospective clinical trial (n = 278), we demonstrated that CNN-based diagnosis of SRH images was noninferior to pathologist-based interpretation of conventional histologic images (overall accuracy, 94.6% versus 93.9%). Our CNNs learned a hierarchy of recognizable histologic feature representations to classify the major histopathologic classes of brain tumors. In addition, we implemented a semantic segmentation method to identify tumor-infiltrated diagnostic regions within SRH images. These results demonstrate how intraoperative cancer diagnosis can be streamlined, creating a complementary pathway for tissue diagnosis that is independent of a traditional pathology laboratory.


Assuntos
Neoplasias Encefálicas/diagnóstico , Sistemas Computacionais , Monitorização Intraoperatória , Redes Neurais de Computação , Análise Espectral Raman , Algoritmos , Neoplasias Encefálicas/diagnóstico por imagem , Ensaios Clínicos como Assunto , Aprendizado Profundo , Humanos , Processamento de Imagem Assistida por Computador , Probabilidade
11.
Int J Radiat Oncol Biol Phys ; 106(2): 413-421, 2020 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-31655198

RESUMO

PURPOSE: The transition from frame-based brain stereotactic radiosurgery (SRS) to frameless delivery is supported by real-time intrafraction monitoring to ensure accurate delivery. The purpose of this study is to characterize these real-time motion traces in a large cohort of patients treated with frameless gated brain SRS and to develop patient-specific predictions of tolerance violations. METHODS AND MATERIALS: SRS patients treated on the Gamma Knife Icon were immobilized using a device-specific thermoplastic head mask. A motion marker was fixed to the patient's nose, with gating and cone beam computed tomography (CBCT)-based corrections to the treatment at excursions from baseline exceeding 1.5 mm. The traces of 1446 fractions were analyzed according to magnitude (932 unique treatment plans for 462 unique individual patients), directional distribution of displacement, and stability. A neural network model was developed to predict interruptions based on a subset of trace data. RESULTS: The average displacement of the marker in the first fraction of all patients was 0.62 ± 0.25 mm with beam CBCT corrections, which would otherwise be modeled at 0.96 ± 0.96 mm without intrafraction motion correction (P < .0001). Twenty-nine percent of fractions delivered were interrupted, of which the Z-axis (superoinferior) motion was the largest contributor to excursion. Baseline corrections significantly compensated for the magnitude of motion in all 3 dimensions (P < .01). The motion relative to the first acquired CBCT was on average seen to consistently increase with treatment time, with the minimum P value occurring at 61.3 minutes. The neural network prediction model was able to predict treatment interruptions with 84% sensitivity on the first 5-minute sample of the trace. CONCLUSIONS: Corrections to marker position significantly decreased marker excursions in all 3 axes compared with a single CBCT alignment. Patient-specific modeling may aid in the optimization of cases selected for frameless radiosurgery to increase the accuracy of planned delivery.


Assuntos
Neoplasias Encefálicas/radioterapia , Sistemas Computacionais , Movimentos dos Órgãos , Radiocirurgia/métodos , Radioterapia Guiada por Imagem/métodos , Neoplasias Encefálicas/diagnóstico por imagem , Tomografia Computadorizada de Feixe Cônico , Marcadores Fiduciais , Humanos , Imobilização/instrumentação , Raios Infravermelhos , Máscaras , Redes Neurais de Computação , Nariz , Radiocirurgia/instrumentação
13.
Anesth Analg ; 130(4): 1002-1007, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-30829666

RESUMO

BACKGROUND: Caudal block, the most common regional anesthetic in children, is predominantly performed using palpation to determine placement. The efficacy of the palpation technique is unknown with respect to block success. While ultrasound has been suggested for use during caudal block, its use is infrequent. METHODS: A single-blinded prospective observational trial was performed evaluating provider success rate of caudal blocks placed by palpation alone. After needle insertion and partial local anesthetic injection, an ultrasound was performed to confirm correct location. RESULTS: A total of 109 caudal blocks were performed during the prospective observational study. Success rate for caudal blocks done by palpation alone was 78.9% as confirmed by ultrasound. In 21.1% of caudal blocks, the provider incorrectly judged the needle to be in the caudal space as confirmed with ultrasound. CONCLUSIONS: Real-time ultrasound visualization of local anesthetic injection provides reliable and immediate confirmation during caudal block in children.


Assuntos
Anestesia Caudal/métodos , Ultrassonografia de Intervenção/métodos , Pré-Escolar , Competência Clínica , Sistemas Computacionais , Feminino , Frequência Cardíaca , Humanos , Lactente , Masculino , Agulhas , Palpação , Estudos Prospectivos , Método Simples-Cego , Falha de Tratamento
14.
Neural Netw ; 121: 366-386, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31593842

RESUMO

Machine learning is yielding unprecedented interest in research and industry, due to recent success in many applied contexts such as image classification and object recognition. However, the deployment of these systems requires huge computing capabilities, thus making them unsuitable for embedded systems. To deal with this limitation, many researchers are investigating brain-inspired computing, which would be a perfect alternative to the conventional Von Neumann architecture based computers (CPU/GPU) that meet the requirements for computing performance, but not for energy-efficiency. Therefore, neuromorphic hardware circuits that are adaptable for both parallel and distributed computations need to be designed. In this paper, we focus on Spiking Neural Networks (SNNs) with a comprehensive study of neural coding methods and hardware exploration. In this context, we propose a framework for neuromorphic hardware design space exploration, which allows to define a suitable architecture based on application-specific constraints and starting from a wide variety of possible architectural choices. For this framework, we have developed a behavioral level simulator for neuromorphic hardware architectural exploration named NAXT. Moreover, we propose modified versions of the standard Rate Coding technique to make trade-offs with the Time Coding paradigm, which is characterized by the low number of spikes propagating in the network. Thus, we are able to reduce the number of spikes while keeping the same neuron's model, which results in an SNN with fewer events to process. By doing so, we seek to reduce the amount of power consumed by the hardware. Furthermore, we present three neuromorphic hardware architectures in order to quantitatively study the implementation of SNNs. One of these architectures integrates a novel hybrid structure: a highly-parallel computation core for most solicited layers, and time-multiplexed computation units for deeper layers. These architectures are derived from a novel funnel-like Design Space Exploration framework for neuromorphic hardware.


Assuntos
Potenciais de Ação/fisiologia , Inteligência Artificial , Encéfalo/fisiologia , Computadores , Redes Neurais de Computação , Neurônios/fisiologia , Sistemas Computacionais , Humanos , Aprendizado de Máquina
15.
BMC Bioinformatics ; 20(Suppl 16): 591, 2019 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-31787090

RESUMO

BACKGROUND: Supercomputers have become indispensable infrastructures in science and industries. In particular, most state-of-the-art scientific results utilize massively parallel supercomputers ranked in TOP500. However, their use is still limited in the bioinformatics field due to the fundamental fact that the asynchronous parallel processing service of Grid Engine is not provided on them. To encourage the use of massively parallel supercomputers in bioinformatics, we developed middleware called Virtual Grid Engine, which enables software pipelines to automatically perform their tasks as MPI programs. RESULT: We conducted basic tests to check the time required to assign jobs to workers by VGE. The results showed that the overhead of the employed algorithm was 246 microseconds and our software can manage thousands of jobs smoothly on the K computer. We also tried a practical test in the bioinformatics field. This test included two tasks, the split and BWA alignment of input FASTQ data. 25,055 nodes (2,000,440 cores) were used for this calculation and accomplished it in three hours. CONCLUSION: We considered that there were four important requirements for this kind of software, non-privilege server program, multiple job handling, dependency control, and usability. We carefully designed and checked all requirements. And this software fulfilled all the requirements and achieved good performance in a large scale analysis.


Assuntos
Algoritmos , Simulação por Computador , Sistemas Computacionais , Interface Usuário-Computador , Humanos , Software
16.
Sensors (Basel) ; 20(1)2019 Dec 24.
Artigo em Inglês | MEDLINE | ID: mdl-31878128

RESUMO

Information about an approaching vehicle is helpful for pedestrians to avoid traffic accidents while most of the past studies related to collision avoidance systems have focused on alerting drivers and controlling vehicles. This paper proposes a technique to detect an approaching vehicle aiming at alerting a pedestrian by observing the variation of the received signal strength indicator (RSSI) of the repeatedly radiated beacons from a vehicle, called the alert beacons. A linear regression algorithm is first applied to RSSI samples. The decision about whether a vehicle is approaching or not is made by the Student's t-test for the linear regression coefficient. A passive method, where the pedestrian's device behaves only as a receiver, is first described. The neighbor-discovery-based (ND-based) method, in which the pedestrian's device repeatedly broadcasts advertising beacons and the moving vehicle in the vicinity returns the alert beacon when it receives the advertising beacon, is then proposed to improve the detection performance as well as reduce the device's energy consumption. The theoretical detection error rate under Rayleigh fading is derived. It is revealed that the proposed ND-based method achieves a lower detection error rate when compared with the passive method under the same delay.


Assuntos
Acidentes de Trânsito/prevenção & controle , Algoritmos , Automóveis , Sistemas Computacionais , Humanos , Pedestres
17.
Opt Express ; 27(24): 35427-35436, 2019 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-31878714

RESUMO

A new strategy is reported here to monitor the enzymatic reactions in real time by using whispering gallery mode (WGM) lasing. The optical microcavity is formed via the self-assembly of an ultraviolet (UV)-treated nematic liquid crystal (LC) 4-cyano-4'-pentylbiphenyl (5CB). The single UV-treated 5CB microdroplet serves as both optical resonator and sensing reactor. The microdroplet configuration transitions induced wavelength shift in the WGM lasing spectra can be used as an indicator for the enzymatic reaction. The proposed sensor has a sub-microgram detection limit of urease (∼0.5 µg/ml), which is lower than the detection limit of currently available urease sensor based on LC materials. Our experimental results demonstrate that WGM lasing has unique advantages in the real-time monitoring of enzymatic reactions compared, for instance, with observation of the optical appearance under a polarized optical microscope.


Assuntos
Sistemas Computacionais , Lasers , Urease/metabolismo , Concentração de Íons de Hidrogênio , Processamento de Imagem Assistida por Computador , Microscopia de Polarização , Fatores de Tempo , Raios Ultravioleta
18.
Sensors (Basel) ; 20(1)2019 Dec 25.
Artigo em Inglês | MEDLINE | ID: mdl-31881651

RESUMO

Isoleucine is one of the branched chain amino acids that plays a major role in the energy metabolism of human beings and animals. However, detailed investigation of specific receptors for isoleucine has not been carried out because of the non-availability of a tool that can monitor the metabolic flux of this amino acid in live cells. This study presents a novel genetically-encoded nanosensor for real-time monitoring of isoleucine in living cells. This nanosensor was developed by sandwiching a periplasmic binding protein (LivJ) of E. coli between a fluorescent protein pair, ECFP (Enhanced Cyan Fluorescent Protein), and Venus. The sensor, named GEII (Genetically Encoded Isoleucine Indicator), was pH stable, isoleucine-specific, and had a binding affinity (Kd) of 63 ± 6 µM. The GEII successfully performed real-time monitoring of isoleucine in bacterial and yeast cells, thereby, establishing its bio-compatibility in monitoring isoleucine in living cells. As a further enhancement, in silico random mutagenesis was carried out to identify a set of viable mutations, which were subsequently experimentally verified to create a library of affinity mutants with a significantly expanded operating range (96 nM-1493 µM). In addition to its applicability in understanding the underlying functions of receptors of isoleucine in metabolic regulation, the GEII can also be used for metabolic engineering of bacteria for enhanced production of isoleucine in animal feed industries.


Assuntos
Técnicas Biossensoriais , Sistemas Computacionais , Isoleucina/análise , Nanopartículas/química , Escherichia coli/citologia , Transferência Ressonante de Energia de Fluorescência , Concentração de Íons de Hidrogênio , Cinética , Ligantes , Viabilidade Microbiana , Simulação de Acoplamento Molecular , Mutação/genética , Saccharomyces cerevisiae/citologia
19.
J Bus Contin Emer Plan ; 13(2): 120-135, 2019 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31779740

RESUMO

The hype surrounding cloud-based disaster recovery (DR) continues to gain steam - and with good reason. That said, due to cost, compatibility and/or organisational restrictions, cloud-based DR is not necessarily the best fit for all systems. This paper presents case studies and a structured approach to evaluate the various options, including public/private cloud DR, DR as a service (DRaaS) and hybrid solutions. For example, the pay-per-use model for cloud DR saves money while the cloud environment is dormant, but results in higher run-time costs than co-location or on-premises solutions when DR is executed. Similarly, organisations need to understand the range of DRaaS options to make an informed decision. Where cloud is not a good fit for all systems, a hybrid solution can satisfy conflicting requirements while leveraging the benefits of cloud where appropriate. Finally, organisational constraints can tip the balance away from what may appear to be the best fit on paper.


Assuntos
Planejamento em Desastres , Desastres , Computação em Nuvem , Sistemas Computacionais
20.
IEEE Trans Biomed Circuits Syst ; 13(6): 1690-1699, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31670678

RESUMO

This work presents a mixed-signal physical-compu-tation-electronics for monitoring three vital signs; namely heart rate, blood pressure, and blood oxygen saturation; from electrocardiography, arterial blood pressure, and photoplethysmography signals in real-time. The computational circuits are implemented on a reconfigurable and programmable signal-processing platform, namely field-programmable analog array (FPAA). The design leverages the core enabling technology of FPAA, namely floating-gate CMOS devices, and an on-chip low-power microcontroller to achieve energy-efficiency while not compromising accuracy. The custom physical-computation-electronics operating in CMOS subthreshold region, performs low-level (i.e., physiologically-relevant feature extraction) and high-level (i.e., detecting arrhythmia) signal processing in an energy-efficient manner. The on-chip microcontroller is used (1) in the programming mode for controlling the charge storage at the analog-memory elements to introduce patient-dependency into the system and (2) in the run mode to quantify the vital signs. The system has been validated against digital computation results from MATLAB using datasets collected from three healthy subjects and datasets from the MIT/BIH open source database. Based on all recordings in the MIT/BIH database, ECG R-peak detection sensitivity is 94.2%. The processor detects arrhythmia in three MIT/BIH recordings with an average sensitivity of 96.2%. The cardiac processor achieves an average percentage mean error bounded by 3.75%, 6.27%, and 7.3% for R-R duration, systolic blood pressure, and oxygen saturation level calculations; respectively. The power consumption of the ECG, blood-pressure and photo-plethysmography processing circuitry are 126 nW, 251 nW and 1.44 µW respectively in a 350 nm process. Overall, the cardiac processor consumes 1.82 µW.


Assuntos
Determinação da Pressão Arterial/instrumentação , Eletrocardiografia/instrumentação , Fotopletismografia/instrumentação , Sinais Vitais/fisiologia , Sistemas Computacionais , Diagnóstico Precoce , Voluntários Saudáveis , Humanos , Dispositivos Lab-On-A-Chip , Semicondutores , Processamento de Sinais Assistido por Computador/instrumentação , Dispositivos Eletrônicos Vestíveis
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA