Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 7 de 7
Filtrar
Mais filtros











Base de dados
Intervalo de ano de publicação
1.
Chem Commun (Camb) ; 53(4): 747-750, 2017 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-27995229

RESUMO

Here, a low-cost perovskite solar cell using CuI and ZnO as the respective inorganic hole and electron transport layers is introduced. Copper foil is chosen as a cheap and low-weight conductive substrate which has a similar work function to ITO. Besides, copper foil is an interesting copper atom source for the growth of the upper cuprous iodide layer on copper foil. A spray coating of a transparent silver nanowire electrode is used as a top contact. The prepared device shows a maximum power conversion efficiency of 12.80% and long-term durability providing an environmentally and market friendly perovskite solar cell.

2.
Appl Opt ; 55(24): 6680-7, 2016 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-27556989

RESUMO

We present transient time analysis of a two-turn optical microfiber coil resonator (MCR). Our dynamic model is based on two sets of equations, coupled mode and nonlinear Schrödinger equations. The pulse response of this device is obtained by numerically solving the modified sets of equations in a dynamic regime. The results show that if the input pulse of the MCR is set at an off-resonance wavelength, this resonator operates as an all-pass filter with neither loss nor time delay. But in the case of resonance, the output pulse may have loss and a relatively long time delay, according to the continuous rotation of light between the first and the second turns of the MCR. Tunable time delays up to td=320 ps are obtained by choosing different values of the coupling coefficients. Furthermore, the material and structural dispersions of the MCR are studied, and it is shown that strong dispersive effects can occur even in this millimeter dimensions photonic device. Pulse broadening and distortion effects of the MCR are studied in the dynamic regime. The results show that, for high bit rate applications, the dispersion effects of the MCR should be carefully considered. Finally, fundamental soliton solution and its conditions in the MCR are investigated.

3.
Appl Opt ; 54(10): 2790-7, 2015 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-25967191

RESUMO

In this paper, we analyze and simulate the lossless propagation of lightwaves in the active metal-semiconductor-metal plasmonic waveguides (MSMPWs) at the wavelength range of 1540-1560 nm using a quantum dot (QD) active medium. The Maxwell's equations are solved in the waveguide, and the required gains for achieving lossless propagation are derived. On the other hand, the rate equations in quantum dot active regions are solved by using the Runge-Kutta method, and the achievable optical gain is derived. The analyses results show that the required optical gain for lossless propagation in MSMPWs is achievable using the QD active medium. Also, by adjusting the active medium parameters, the MSMPWs loss can be eliminated in a specific bandwidth, and the propagation length increases obviously.

4.
Zentralbl Chir ; 137(3): 214-22, 2012 Jun.
Artigo em Alemão | MEDLINE | ID: mdl-22711320

RESUMO

Pneumothorax is defined as the accumulation of air in the pleural space. A distinction is made between a primary (idiopathic) spontaneous pneumothorax (PSP), secondary spontaneous pneumothorax (SSP) as well as between iatrogenic pneumothorax and traumatic pneumothorax. Primary spontaneous pneumothorax (PSP) occurs mainly in otherwise healthy people (mainly tall and thin young men) without any clinical sign of lung disease. In contrast, secondary pneumothorax (SSP) mostly occurs in patients with diagnosed and clinically manifested lung disease and is most frequent in older subjects (> 50 years). Smokers have a higher risk of developing pneumothorax. Most pneumothorax cases require a therapeutic intervention using thorax drainage. Observation alone is recommended for only those few patients suffering from pneumothorax without clinical symptoms. Although simple needle aspiration is often recommended as a first-line treatment, our clinical experience shows no advantage for most of the patients. All patients with symptomatic pneumothorax should be treated with immediate intercostal tube drainage. In the surgical therapy of pneumothorax, VATS (video-assisted thoracic surgery) is the current effective standard treatment. Open posterolateral thoracotomy is the recommend approach rather than the minimally invasive procedure in patient with serious illness or complications. The aim of both interventions is to reduce the recurrence rate of pneumothorax as much as possible.


Assuntos
Pneumotórax/cirurgia , Tubos Torácicos , Humanos , Pneumopatias/complicações , Pneumopatias/cirurgia , Procedimentos Cirúrgicos Minimamente Invasivos/métodos , Dor Pós-Operatória/etiologia , Pneumotórax/etiologia , Prognóstico , Fatores de Risco , Prevenção Secundária , Fumar/efeitos adversos , Sucção/métodos , Doenças Torácicas/complicações , Doenças Torácicas/cirurgia , Traumatismos Torácicos/complicações , Traumatismos Torácicos/cirurgia , Cirurgia Torácica Vídeoassistida/métodos , Toracotomia/métodos
5.
Scanning ; 31(2): 65-74, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19191264

RESUMO

Scanning tunneling microscope (STM) has found a wide application in nanoscience and nanotechnology. This microscope uses an ultra-sharp metallic tip for image acquisition. Resolution of STM images depends largely on the radius of the tip apex; the smaller the radius the higher the resolution. In the present research, an experimental set-up was designed and implemented for fabrication of STM tungsten nanotip using electrochemical-etching method with the aim of optimization of nanotip fabrication process parameters by using Taguchi method. These parameters are electrolyte concentration, immersion length of the tungsten wire, inner diameter of the cathode tube, and the process voltage. It was found that the optimum level of the process parameters for gaining minimum radius of the nanotip apex is electrolyte concentration of 2 M/lit, wire immersion length of 4 mm, cathode tube inner diameter of 55 mm, and voltage of 3.5 V within the range of experiments. By setting the process parameters on the optimum level, the radius of the nanotip apex was decreased by five times in comparison to the mean value of the experimental results. The radius of the nanotip apex was improved down to about 10 nm under the optimum conditions. SCANNING 31: 65-74, 2009. (c) 2009 Wiley Periodicals, Inc.

6.
Anaesthesist ; 57(10): 982-7, 2008 Oct.
Artigo em Alemão | MEDLINE | ID: mdl-18597061

RESUMO

The case of a 69-year-old patient is reported with non-small cell lung cancer who underwent lobectomy with sleeve resection and postoperatively developed intermittent atrial tachyarrhythmia. The patient was treated with a beta-blocker and the class III antiarrhythmic drug amiodarone, which resulted in normal frequency sinus rhythm. After pharmacological saturation with amiodarone, fibrosis of the lungs developed with subsequent respiratory insufficiency. Despite maximum intensive care therapy the patient died 9 weeks after surgery of hypoxemia-related multiple organ dysfunction syndrome. Based on this case amiodarone-related pneumonitis will be discussed, which due to a lack of pathognomonic symptoms is often difficult to diagnose and for which there are few treatment options available. The differential diagnoses of pneumonitis will also be discussed.


Assuntos
Amiodarona/efeitos adversos , Antiarrítmicos/efeitos adversos , Pneumonia/induzido quimicamente , Procedimentos Cirúrgicos Torácicos , Idoso , Amiodarona/uso terapêutico , Antiarrítmicos/uso terapêutico , Carcinoma Pulmonar de Células não Pequenas/cirurgia , Diagnóstico Diferencial , Evolução Fatal , Fibrose/induzido quimicamente , Fibrose/patologia , Humanos , Hipóxia/etiologia , Neoplasias Pulmonares/cirurgia , Masculino , Insuficiência de Múltiplos Órgãos/etiologia , Pneumonia/diagnóstico , Taquicardia/complicações , Taquicardia/tratamento farmacológico
7.
Z Rheumatol ; 64(7): 488-98, 2005 Oct.
Artigo em Alemão | MEDLINE | ID: mdl-16244832

RESUMO

OBJECTIVE: Increasing bone mineral density (BMD) has been found in several studies in patients with osteoarthritis. Therefore, many clinicians deny the simultaneous occurrence of osteoporosis (OP) and osteoarthritis (OA). Because of our clinical impression however, we suggested that we have to consider a common occurrence. Furthermore, the value of markers of bone turn over with a view to early diagnosis of OP and or as an assessment for bone metabolism in OA is still a matter debate and their clinical use has not been clearly defined in the management of the individual patient. METHOD: The BMD of the lumbar spine and the proximal femur of 119 OA patients (83 postmenopausal female patients aged 50-83 and 35 male patients aged 36-86 years) who subsequently required hip or knee replacements, but were otherwise healthy, were measured by dual energy X-ray absorption (DXA), Hologic QDR-2000. We also measured biochemical markers of bone turn over, i. e., CICP, ICTP, DPD, PTH, estrogen, testosterone, bAP, hydroxy vitamin D and the normal blood count. RESULTS: There was a high occurrence of a low BMD among the patients. A total of 28.9% of women were affected by OP and 52.9% by osteopoenie. This reflects the normal distribution of OP in the female population. Of the male patients 20% had OP and 38.8% osteopoenie. This is astonishing high. Age proved to be a significant factor in the degree of BMD. An association between disuse osteoporosis and degree of BMD in the OA affected joint could not be proven. The use of the biochemical markers for an earlier diagnosis or to assess bone metabolism in OP and OA was not possible. CONCLUSION: We can not support the hypotheses that OA prevents OP. Moreover, the occurrence of OP in our study reflected the incidence of OP in the average female and the astonishingly high incidence in the male population; however does not mean that the two conditions are mutually exclusive. We did not find that the biochemical markers of bone turn over could deliver additional information with respect to bone metabolism and an earlier diagnosis of OP.


Assuntos
Densidade Óssea , Reabsorção Óssea/diagnóstico , Reabsorção Óssea/epidemiologia , Osteoartrite/diagnóstico , Osteoartrite/epidemiologia , Osteoporose/diagnóstico , Osteoporose/epidemiologia , Absorciometria de Fóton/estatística & dados numéricos , Adulto , Idoso , Idoso de 80 Anos ou mais , Biomarcadores/sangue , Reabsorção Óssea/sangue , Comorbidade , Feminino , Alemanha/epidemiologia , Humanos , Incidência , Pessoa de Meia-Idade , Osteoartrite/sangue , Osteoporose/sangue , Prognóstico , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA