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1.
BMC Infect Dis ; 19(1): 961, 2019 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-31711425

RESUMO

BACKGROUND: Clostridioides difficile is considered the main pathogen responsible for hospital-acquired infections. This prospective study determined the prevalence, molecular epidemiological characteristics, and risk factors for C. difficile infection (CDI) and C. difficile colonization (CDC) among patients in the intensive care unit (ICU) of a large-scale tertiary hospital in China, with the aim of providing strategies for efficient CDI and CDC prevention and control. METHODS: Stool samples were collected and anaerobically cultured for C. difficile detection. The identified isolates were examined for toxin genes and subjected to multilocus sequence typing. Patients were classified into CDI, CDC, and control groups, and their medical records were analyzed to determine the risk factors for CDI and CDC. RESULTS: Of the 800 patients included in the study, 33 (4.12%) and 25 (3.12%) were identified to have CDI and CDC, respectively. Associations with CDI were found for fever (OR = 13.993), metabolic disorder (OR = 7.972), and treatment with fluoroquinolone (OR = 42.696) or combined antibiotics (OR = 2.856). CDC patients were characterized by prolonged hospital stay (OR = 1.137), increased number of comorbidities (OR = 36.509), respiratory diseases (OR = 0.043), and treatment with vancomycin (OR = 18.168). Notably, treatment with metronidazole was found to be a protective factor in both groups (CDI: OR = 0.042; CDC: OR = 0.013). Eighteen sequence types (STs) were identified. In the CDI group, the isolated strains were predominantly toxin A and toxin B positive (A + B+) and the epidemic clone was genotype ST2. In the CDC group, the dominant strains were A + B+ and the epidemic clone was ST81. CONCLUSIONS: The prevalences of CDC and CDI in our ICU were relatively high, suggesting the importance of routine screening for acquisition of C. difficile. Future prevention and treatment strategies for CDC and CDI should consider hospital stay, enteral nutrition, underlying comorbidities, and use of combined antibiotics. Moreover, metronidazole may be a protective factor for both CDI and CDC, and could be used empirically.

2.
Nat Nanotechnol ; 14(5): 473-479, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30833690

RESUMO

Superconducting nanowire single-photon detectors with peak efficiencies above 90% and unrivalled timing jitter (<30 ps) have emerged as a potent technology for quantum information and sensing applications. However, their high cost and cryogenic operation limit their widespread applicability. Here, we present an approach using tapered InP nanowire p-n junction arrays for high-efficiency, broadband and high-speed photodetection without the need for cryogenic cooling. The truncated conical nanowire shape enables a broadband, linear photoresponse in the ultraviolet to near-infrared range (~500 nm bandwidth) with external quantum efficiencies exceeding 85%. The devices exhibit a high gain beyond 105, such that a single photon per pulse can be distinguished from the dark noise, while simultaneously showing a fast pulse rise time (<1 ns) and excellent timing jitter (<20 ps). Such detectors open up new possibilities for applications in remote sensing, dose monitoring for cancer treatment, three-dimensional imaging and quantum communication.

3.
PLoS One ; 14(2): e0211893, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30730963

RESUMO

BACKGROUND: Osteoporosis is a chronic disease whose prevention is more effective than treatment, but it may be necessary to change people's self-efficacy to prevent this condition. This article aimed to study the pathway among information, beliefs and self-efficacy in osteoporosis prevention, and support further intervention. METHODS: A cross-sectional study was conducted among community residents over 40 years old from two volunteer communities in urban Shanghai, China. Of 450 middle-aged and older community residents who volunteered to participate in the study, 421 (93.5%) finished the field survey effectively. RESULTS: 62.9% of the residents were females. Their mean age was 64.4 ± 11.2 years. The residents showed low knowledge of osteoporosis-related information, and the mean percentage of correct response was just 61.2%. In univariate analysis, information (univariate ß = 0.27, 95% CI = 0.15-0.38) and beliefs (univariate ß = 0.31, 95% CI = 0.25-0.38) were associated with self-efficacy. Multivariate analysis showed that information (multiple ß = 0.19, 95% CI = 0.09-0.36) and belief (multiple ß = 0.30, 95% CI = 0.23-0.36) remained significant. And in the path analysis, self-efficacy was significantly predicted by beliefs (ß = 0.81, p<0.001). CONCLUSIONS: The study highlighted the urgency of conducting the osteoporosis preventive health promotion among middle-aged and older people as their lack of information and low level of beliefs and self-efficacy about osteoporosis prevention. Future interventions should focus on improving beliefs, especially perceived benefits, perceived threats, and action clues, on osteoporosis prevention in this group.


Assuntos
Cultura , Conhecimentos, Atitudes e Prática em Saúde , Osteoporose/prevenção & controle , População Urbana , Adulto , Idoso , China , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
4.
ACS Nano ; 10(12): 11414-11419, 2016 12 27.
Artigo em Inglês | MEDLINE | ID: mdl-28024324

RESUMO

Photovoltaic cells based on arrays of semiconductor nanowires promise efficiencies comparable or even better than their planar counterparts with much less material. One reason for the high efficiencies is their large absorption cross section, but until recently the photocurrent has been limited to less than 70% of the theoretical maximum. Here we enhance the absorption in indium phosphide (InP) nanowire solar cells by employing broadband forward scattering of self-aligned nanoparticles on top of the transparent top contact layer. This results in a nanowire solar cell with a photovoltaic conversion efficiency of 17.8% and a short-circuit current of 29.3 mA/cm2 under 1 sun illumination, which is the highest reported so far for nanowire solar cells and among the highest reported for III-V solar cells. We also measure the angle-dependent photocurrent, using time-reversed Fourier microscopy, and demonstrate a broadband and omnidirectional absorption enhancement for unpolarized light up to 60° with a wavelength average of 12% due to Mie scattering. These results unambiguously demonstrate the potential of semiconductor nanowires as nanostructures for the next generation of photovoltaic devices.

5.
Nanotechnology ; 27(45): 454003, 2016 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-27727149

RESUMO

Nanowire based solar cells have attracted great attention due to their potential for high efficiency and low device cost. Photovoltaic devices based on InP nanowires now have characteristics comparable to InP bulk solar cells. A detailed and direct correlation of the influence of growth conditions on performance is necessary to improve efficiency further. We explored the effects of the growth temperature, and of the addition of HCl during growth, on the efficiency of nanowire array based solar cell devices. By increasing HCl, the saturation dark current was reduced, and thereby the nanowire solar cell efficiency was enhanced from less than 1% to 7.6% under AM 1.5 illumination at 1 sun. At the same time, we observed that the solar cell efficiency decreased by increasing the tri-methyl-indium content, strongly suggesting that these effects are carbon related.

6.
Nat Commun ; 6: 7824, 2015 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-26183949

RESUMO

Photoelectrochemical hydrogen production from solar energy and water offers a clean and sustainable fuel option for the future. Planar III/V material systems have shown the highest efficiencies, but are expensive. By moving to the nanowire regime the demand on material quantity is reduced, and new materials can be uncovered, such as wurtzite gallium phosphide, featuring a direct bandgap. This is one of the few materials combining large solar light absorption and (close to) ideal band-edge positions for full water splitting. Here we report the photoelectrochemical reduction of water, on a p-type wurtzite gallium phosphide nanowire photocathode. By modifying geometry to reduce electrical resistance and enhance optical absorption, and modifying the surface with a multistep platinum deposition, high current densities and open circuit potentials were achieved. Our results demonstrate the capabilities of this material, even when used in such low quantities, as in nanowires.

7.
Nano Lett ; 14(7): 3715-9, 2014 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-24875657

RESUMO

Semiconductor nanowire arrays are expected to be advantageous for photoelectrochemical energy conversion due to their reduced materials consumption. In addition, with the nanowire geometry the length scales for light absorption and carrier separation are decoupled, which should suppress bulk recombination. Here, we use vertically aligned p-type InP nanowire arrays, coated with noble-metal-free MoS3 nanoparticles, as the cathode for photoelectrochemical hydrogen production from water. We demonstrate a photocathode efficiency of 6.4% under Air Mass 1.5G illumination with only 3% of the surface area covered by nanowires.

8.
Nano Lett ; 13(9): 4113-7, 2013 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-23898896

RESUMO

We demonstrate an efficiency enhancement of an InP nanowire (NW) axial p-n junction solar cell by cleaning the NW surface. NW arrays were grown with in situ HCl etching on an InP substrate patterned by nanoimprint lithography, and the NWs surfaces were cleaned after growth by piranha etching. We find that the postgrowth piranha etching is critical for obtaining a good solar cell performance. With this procedure, a high diode rectification factor of 10(7) is obtained at ±1 V. The resulting NW solar cell exhibits an open-circuit voltage (Voc) of 0.73 V, a short-circuit current density (Jsc) of 21 mA/cm(2), and a fill factor (FF) of 0.73 at 1 sun. This yields a power conversion efficiency of up to 11.1% at 1 sun and 10.3% at 12 suns.

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