Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 18 de 18
Filtrar
Mais filtros

Bases de dados
País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
1.
Postgrad Med J ; 96(1139): 556-559, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32467108

RESUMO

INTRODUCTION: Continuous cardiac monitoring in non-critical care settings is expensive and overutilised. As such, it is an important target of hospital interventions to establish cost-effective, high-quality care. Since inappropriate telemetry use was persistently elevated at our institution, we devised an electronic best practice alert (BPA) and tested it in a randomised controlled fashion. METHODS: Between 4 March 2018 and 5 July 2018 at our 600-bed academic hospital, all non-critical care patients who had at least one telemetry order were randomised to the control or intervention group. The intervention group received daily BPAs if telemetry was active. RESULTS: 275 and 283 patients were randomised to the intervention and control groups, respectively. The intervention group triggered 1042 alerts and trended toward fewer telemetry days (3.8 vs 5.0, p=0.017). The intervention group stopped telemetry 31.7% of the alerted patient-days compared with 23.3% for the control group (OR 1.53, 95% CI 1.24 to 1.88, p<0.001). There were no significant differences in length of stay, rapid responses, code blues, or mortality between the two groups. CONCLUSIONS: Using a randomised controlled design, we show that BPAs significantly reduce telemetry without negatively affecting patient outcomes. They should have a role in promoting high-value telemetry use.


Assuntos
Sistemas de Apoio a Decisões Clínicas , Tempo de Internação/estatística & dados numéricos , Melhoria de Qualidade , Telemetria/métodos , Idoso , Idoso de 80 Anos ou mais , Reanimação Cardiopulmonar , Análise Custo-Benefício , Feminino , Mortalidade Hospitalar , Equipe de Respostas Rápidas de Hospitais , Humanos , Masculino , Pessoa de Meia-Idade , Razão de Chances , Guias de Prática Clínica como Assunto , Telemetria/economia , Telemetria/estatística & dados numéricos
2.
Nano Lett ; 18(11): 6906-6914, 2018 11 14.
Artigo em Inglês | MEDLINE | ID: mdl-30339762

RESUMO

Light-emitting sources and devices permeate every aspect of our lives and are used in lighting, communications, transportation, computing, and medicine. Advances in multifunctional and "smart lighting" would require revolutionary concepts in the control of emission spectra and directionality. Such control might be possible with new schemes and regimes of light-matter interaction paired with developments in light-emitting materials. Here we show that all-dielectric metasurfaces made from III-V semiconductors with embedded emitters have the potential to provide revolutionary lighting concepts and devices, with new functionality that goes far beyond what is available in existing technologies. Specifically, we use Mie-resonant metasurfaces made from semiconductor heterostructures containing epitaxial quantum dots. By controlling the symmetry of the resonant modes, their overlap with the emission spectra, and other structural parameters, we can enhance the brightness by 2 orders of magnitude, as well as reduce its far-field divergence significantly.

3.
Nano Lett ; 17(2): 1049-1055, 2017 02 08.
Artigo em Inglês | MEDLINE | ID: mdl-28118019

RESUMO

We report lasing from nonpolar p-i-n InGaN/GaN multi-quantum well core-shell single-nanowire lasers by optical pumping at room temperature. The nanowire lasers were fabricated using a hybrid approach consisting of a top-down two-step etch process followed by a bottom-up regrowth process, enabling precise geometrical control and high material gain and optical confinement. The modal gain spectra and the gain curves of the core-shell nanowire lasers were measured using micro-photoluminescence and analyzed using the Hakki-Paoli method. Significantly lower lasing thresholds due to high optical gain were measured compared to previously reported semipolar InGaN/GaN core-shell nanowires, despite significantly shorter cavity lengths and reduced active region volume. Mode simulations show that due to the core-shell architecture, annular-shaped modes have higher optical confinement than solid transverse modes. The results show the viability of this p-i-n nonpolar core-shell nanowire architecture, previously investigated for next-generation light-emitting diodes, as low-threshold, coherent UV-visible nanoscale light emitters, and open a route toward monolithic, integrable, electrically injected single-nanowire lasers operating at room temperature.


Assuntos
Gálio/química , Índio/química , Lasers , Nanofios/química , Nitrogênio/química , Luz , Nanocompostos/química , Nanotecnologia , Tamanho da Partícula , Semicondutores , Relação Estrutura-Atividade , Propriedades de Superfície
4.
Nano Lett ; 14(8): 4293-8, 2014 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-24987800

RESUMO

Single crystalline nanomembranes (NMs) represent a new embodiment of semiconductors having a two-dimensional flexural character with comparable crystalline perfection and optoelectronic efficacy. In this Letter, we demonstrate the preparation of GaN NMs with a freestanding thickness between 90 to 300 nm. Large-area (>5 × 5 mm(2)) GaN NMs can be routinely obtained using a procedure of conductivity-selective electrochemical etching. GaN NM is atomically flat and possesses an optical quality similar to that from bulk GaN. A light-emitting optical heterostructure NM consisting of p-GaN/InGaN quantum wells/GaN is prepared by epitaxy, undercutting etching, and layer transfer. Bright blue light emission from this heterostructure validates the concept of NM-based optoelectronics and points to potentials in flexible applications and heterogeneous integration.

5.
Nanotechnology ; 25(22): 225602, 2014 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-24807561

RESUMO

Ternary InGaN nanorods were prepared on dielectric-masked nano-holes with selective area metalorganic chemical vapor deposition. To overcome the tendency for random nucleation of GaN at low temperatures, a pulsed growth procedure was introduced to enhance the diffusion length of Ga adatoms on SiO2, resulting in good selectivity at typical temperature ranges for InGaN. Photoluminescence from the InGaN nanorods can be tuned from near ultraviolet (400 nm) to blue-green (~500 nm). Microstructural properties were characterized by transmission electron microscopy; threading dislocations from the underlying GaN template were terminated at the nanorod/template interface, resulting in dislocation-free nanorods. The height of dislocation-free InGaN nanorods is about 150 nm, which is much larger than the critical thickness for the onset of misfit dislocations in planar InGaN growth with typical thickness of less than 10 nm for an indium composition between 10 and 20%. The composition profile of In along the growth direction was examined by energy dispersive x-ray spectroscopic mapping and line scan. Oscillations of In composition along the growth direction were observed and are likely due to the kinetic competition between In and Ga adatoms. These InGaN nanorods are expected to be useful as templates for growing higher In composition nano-light-emitting diodes.

6.
Neuron ; 53(1): 103-15, 2007 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-17196534

RESUMO

Drosophila mushroom bodies (MB) are bilaterally symmetric multilobed brain structures required for olfactory memory. Previous studies suggested that neurotransmission from MB neurons is only required for memory retrieval. Our unexpected observation that Dorsal Paired Medial (DPM) neurons, which project only to MB neurons, are required during memory storage but not during acquisition or retrieval, led us to revisit the role of MB neurons in memory processing. We show that neurotransmission from the alpha'beta' subset of MB neurons is required to acquire and stabilize aversive and appetitive odor memory, but is dispensable during memory retrieval. In contrast, neurotransmission from MB alphabeta neurons is only required for memory retrieval. These data suggest a dynamic requirement for the different subsets of MB neurons in memory and are consistent with the notion that recurrent activity in an MB alpha'beta' neuron-DPM neuron loop is required to stabilize memories formed in the MB alphabeta neurons.


Assuntos
Drosophila/fisiologia , Memória/fisiologia , Corpos Pedunculados/fisiologia , Neurônios/fisiologia , Odorantes , Olfato/fisiologia , Animais , Animais Geneticamente Modificados , Aprendizagem da Esquiva/fisiologia , Drosophila/citologia , Drosophila/genética , Estimulação Elétrica , Regulação da Expressão Gênica no Desenvolvimento/genética , Corpos Pedunculados/citologia , Mutação/genética , Rede Nervosa/citologia , Rede Nervosa/fisiologia , Vias Neurais/citologia , Vias Neurais/fisiologia , Neurônios/citologia , Transmissão Sináptica/fisiologia
7.
Nanotechnology ; 22(4): 045603, 2011 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-21169658

RESUMO

A simple yet versatile nanoetching process in porosifying and 'machining' GaN is reported in this work. By combining different porosifying conditions through potentiostatic modulation or embedding doping design, we are able to separate and lift off GaN layers over a macroscopic area (≥cm(2)). Strain relaxation and single crystallinity are confirmed by Raman and transmission electron microscopy, respectively. This method is expected to open up a new dimension in epitaxy, design and manufacture of GaN heterostructures and devices.

8.
Curr Biol ; 16(15): 1524-30, 2006 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-16890528

RESUMO

Memories are formed, stabilized in a time-dependent manner, and stored in neural networks. In Drosophila, retrieval of punitive and rewarded odor memories depends on output from mushroom body (MB) neurons, consistent with the idea that both types of memory are represented there. Dorsal Paired Medial (DPM) neurons innervate the mushroom bodies, and DPM neuron output is required for the stability of punished odor memory. Here we show that stable reward-odor memory is also DPM neuron dependent. DPM neuron expression of amnesiac (amn) in amn mutant flies restores wild-type memory. In addition, disrupting DPM neurotransmission between training and testing abolishes reward-odor memory, just as it does with punished memory. We further examined DPM-MB connectivity by overexpressing a DScam variant that reduces DPM neuron projections to the MB alpha, beta, and gamma lobes. DPM neurons that primarily project to MB alpha' and beta' lobes are capable of stabilizing punitive- and reward-odor memory, implying that both forms of memory have similar circuit requirements. Therefore, our results suggest that the fly employs the local DPM-MB circuit to stabilize punitive- and reward-odor memories and that stable aspects of both forms of memory may reside in mushroom body alpha' and beta' lobe neurons.


Assuntos
Drosophila melanogaster/fisiologia , Memória/fisiologia , Corpos Pedunculados/fisiologia , Rede Nervosa/fisiologia , Neurônios/fisiologia , Animais , Moléculas de Adesão Celular , Proteínas de Drosophila/metabolismo , Proteínas de Fluorescência Verde/metabolismo , Corpos Pedunculados/inervação , Odorantes , Recompensa
9.
Can J Gastroenterol ; 21(9): 565-8, 2007 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-17853950

RESUMO

BACKGROUND: It has been previously reported that British Columbia's (BC's) First Nations (Aboriginal) community has an increased risk of autoimmune diseases, including rheumatological conditions (rheumatoid arthritis, systemic lupus) and primary biliary cirrhosis. The researchers hypothesized that this community may also be at increased risk for autoimmune hepatitis (AIH). METHODS: Independent, retrospective reviews of the databases of two separate tertiary/quaternary British Columbia university-affiliated health care institutions, the Adult Liver Transplant Program of the BC Transplant Society and the Division of Pediatric Gastroenterology, BC Children's Hospital (Vancouver, BC), were performed. All patients referred with a diagnosis of probable or definite AIH who identified themselves as being of First Nations descent from 1988 to 2004 were reviewed. The liver transplant database records all adult patients in the province referred for transplant assessment. The pediatric database records all children referred to the BC Children's Hospital. RESULTS: A total of 68 adult patients with a definite or probable diagnosis of AIH were referred to the liver transplant program. Twelve patients (17.6%) were Aboriginal, 11 of which were female. Similarly, a total of 30 children with probable or definite AIH were identified from the pediatric database. Six of these cases (20%) were identified in Aboriginal children. CONCLUSIONS: The findings suggest an increased prevalence of AIH among BC's First Nations community. A disproportionate First Nations representation was found on independent review of two databases. Future studies are needed to determine the true prevalence of AIH in this community, and to uncover the genetic predisposition and the environmental triggers explaining this phenomenon.


Assuntos
Hepatite Autoimune/etnologia , Hepatite Autoimune/epidemiologia , Indígenas Norte-Americanos , Adolescente , Adulto , Colúmbia Britânica/epidemiologia , Criança , Pré-Escolar , Bases de Dados Factuais , Feminino , Humanos , Indígenas Norte-Americanos/etnologia , Lactente , Recém-Nascido , Transplante de Fígado/etnologia , Masculino , Pessoa de Meia-Idade , Prevalência , Estudos Retrospectivos , Fatores de Risco
10.
Trends Neurosci ; 27(9): 511-3, 2004 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-15331230

RESUMO

To understand the role of a gene in adult behavior, it is necessary to control its expression in four dimensions: space and time. Two recent papers describe implementation of different but related technologies that now provide this missing element in fly behavioral research.


Assuntos
Comportamento Animal/fisiologia , Drosophila/genética , Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Expressão Gênica/fisiologia , Animais , Marcação de Genes , Genes de Insetos/fisiologia , Genes de Troca/fisiologia , Modelos Moleculares
11.
Nat Rev Drug Discov ; 19(3): 158, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32127661
12.
Sci Rep ; 4: 5514, 2014 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-24981889

RESUMO

Multi-color and broadband visible emission was realized thorough the hexagonal annular structure of GaN. The annular structure fabricated by selective-area growth emitted purple, blue and green color-emission from the multi-facets. The hexagonal annular structure provided various sidewalls of {101} and {112} semi-polar facets, and (0001) polar facet. From the cathodoluminescence study, the (0001) plane had the longest wavelength of 525 nm, and the {101} facet of 440 nm peak wavelength had longer wavelength emission than the {112} of 412 nm peak wavelength. The origin of longer wavelength emission of {101} was mostly due to high In-composition, as well as slightly larger well thickness, which means that {101} facet has higher In-incorporation efficiency. Various In-composition of each facet provided multi-color and broadband emission with the international commission on illumination (CIE) of (0.22, 0.45) and high emission efficiency. The hexagonal annular structure becomes building blocks for highly efficient broadband visible lighting sources.

13.
ACS Appl Mater Interfaces ; 5(21): 11074-9, 2013 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-24125198

RESUMO

Nanoporous (NP) gallium nitride (GaN) as a new class of GaN material has many interesting properties that the conventional GaN material does not have. In this paper, we focus on the mechanical properties of NP GaN, and the detailed physical mechanism of porous GaN in the application of liftoff. A decrease in elastic modulus and hardness was identified in NP GaN compared to the conventional GaN film. The promising application of NP GaN as release layers in the mechanical liftoff of GaN thin films and devices was systematically studied. A phase diagram was generated to correlate the initial NP GaN profiles with the as-overgrown morphologies of the NP structures. The fracture toughness of the NP GaN release layer was studied in terms of the voided-space-ratio. It is shown that the transformed morphologies and fracture toughness of the NP GaN layer after overgrowth strongly depends on the initial porosity of NP GaN templates. The mechanical separation and transfer of a GaN film over a 2 in. wafer was demonstrated, which proves that this technique is useful in practical applications.


Assuntos
Gálio/química , Nanoporos/ultraestrutura , Nanoestruturas/química , Nanotecnologia , Módulo de Elasticidade , Fenômenos Mecânicos , Propriedades de Superfície
15.
Fly (Austin) ; 3(1): 3-9, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19164943

RESUMO

A biological understanding of memory remains one of the great quests of neuroscience. For over 30 years the fruit fly Drosophila melanogaster has primarily been viewed as an excellent vehicle to find 'memory genes'. However, the recent advent of sophisticated genetic tools to manipulate neural activity has meant that these genes can now be viewed within the context of functioning neural circuits. A holistic understanding of memory in flies is therefore now a realistic goal. Larvae and adult flies exhibit remarkable behavioral complexity and they can both be trained in a number of ways. In this review, our intention is to summarize the many assays that have been developed to study plastic behaviors in flies. More specific and detailed reviews have been published by us and others, reviewed in references 1-6. While our bias for olfactory conditioning paradigms is obvious, our purpose here is not to pass judgment on each method. We would rather leave that to those readers who might be inspired to try each assay for themselves.


Assuntos
Drosophila melanogaster/fisiologia , Animais , Comportamento Animal , Condicionamento Psicológico , Feminino , Larva/fisiologia , Aprendizagem , Masculino , Memória
17.
Cell ; 128(3): 431-2, 2007 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-17289561

RESUMO

In the fly antennal lobe projection neurons receive odor information from olfactory sensory neurons and transmit it to higher brain centers. However, projection neurons respond differently to odors than sensory neurons, despite the fact that they appear to have one-to-one connectivity. Shang et al. (2007) now describe the existence of excitatory neurons within the antennal lobe that may account for some of these unexplained differences.


Assuntos
Drosophila/fisiologia , Neurônios Aferentes/fisiologia , Odorantes , Animais , Encéfalo/fisiologia , Neurônios Receptores Olfatórios/fisiologia , Olfato
18.
Gynecol Oncol ; 85(1): 59-66, 2002 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-11925121

RESUMO

OBJECTIVES: The aim of this study was to determine cervical cancer cell sensitivity to chemotherapy-induced apoptosis based on human papillomavirus (HPV) status. METHODS: CaSki (HPV-positive) and C33A (HPV-negative) cells were treated with camptothecin or cisplatin. Cellular viability was determined by trypan blue exclusion. Apoptotic indexes were determined by flow cytometric analysis of annexin V labeling and morphological changes. Mitochondrial release of cytochrome c was determined by immunofluorescence using confocal microscopy. Caspase 3 activation and bax expression were assessed by immunoblotting. RESULTS: CaSki cells displayed chemoresistance to both camptothecin and cisplatin. Low response to apoptogenic stimuli was evidenced by a marginal increase in the apoptotic cell fraction after camptothecin treatment (22.9 +/- 2.56%) compared with control (17.8 +/- 1.95%). Cisplatin (14.8 +/- 1.01%) caused a slight decrease in apoptosis. Mitochondrial release of cytochrome c and cleavage of caspase 3 could not be demonstrated in CaSki cells after treatment. Despite p53 mutation, C33A cells were sensitive to the antiproliferative effects of camptothecin and cisplatin. Mean apoptotic events were 17.5 +/- 0.33 for control, 42 +/- 1.76 for cisplatin, and 38.1 +/- 0.75 for camptothecin. An intact cytochrome c pathway was demonstrated in C33A cells leading to cleavage of caspase 3 after camptothecin treatment. The constitutive bax expression demonstrated in both cell lines displayed no change after camptothecin treatment. CONCLUSION: HPV-positive cervical cancer cells have an inherent resistance to chemotherapy-induced apoptosis. HPV-dependant inactivation of apoptotic regulators such as p53 and blockage of downstream events such as cytochrome c release and caspase 3 activation might be elemental to this cellular survival advantage provided by high-risk oncogenic papillomavirus.


Assuntos
Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Camptotecina/farmacologia , Cisplatino/farmacologia , Papillomaviridae , Proteínas Proto-Oncogênicas c-bcl-2 , Neoplasias do Colo do Útero/tratamento farmacológico , Neoplasias do Colo do Útero/virologia , Anexina A5 , Caspase 3 , Caspases/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Grupo dos Citocromos c/metabolismo , Ativação Enzimática , Feminino , Citometria de Fluxo , Humanos , Proteínas Proto-Oncogênicas/biossíntese , Células Tumorais Cultivadas , Neoplasias do Colo do Útero/patologia , Proteína X Associada a bcl-2
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA