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1.
Artigo em Inglês | MEDLINE | ID: mdl-35133260

RESUMO

Three novel strains of Gram-stain-negative, obligately anaerobic, spore-forming straight or slightly curved rods with pointed ends occurring singly or in pairs were isolated from the faeces of healthy human children. The strains were characterized by mesophilic fermentative metabolism and production of acetate, ethanol and H2 as the end metabolic products. Strains ASD3451 and ASD5720T were motile, fermented lactose and raffinose, and weakly fermented maltose. Strain ASD4241T was non-motile and did not ferment the carbohydrates listed above but fermented starch. Strains ASD3451 and ASD5720T shared average nucleotide identity higher than 98.5 % with each other, while ASD4241T had only 88.5-89 % identity to them. Based on phylogenetic and chemotaxonomic analyses, we propose Diplocloster agilis gen. nov., sp. nov. (ASD5720T=JCM 34353T=VKM B-3497T) and Diplocloster modestus sp. nov. (ASD4241T=JCM 34351T=VKM B-3498T) within the family Lachnospiraceae.


Assuntos
Fezes/microbiologia , Firmicutes/classificação , Filogenia , Anaerobiose , Técnicas de Tipagem Bacteriana , Composição de Bases , Criança , DNA Bacteriano/genética , Ácidos Graxos/química , Firmicutes/isolamento & purificação , Humanos , RNA Ribossômico 16S/genética , Análise de Sequência de DNA
2.
Rev Sci Instrum ; 92(4): 043707, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-34243372

RESUMO

An automatic target monitoring method based on photographs taken by a CMOS photo-camera has been developed for the MEG II detector. The technique could be adapted for other fixed-target experiments requiring good knowledge of their target position to avoid biases and systematic errors in measuring the trajectories of the outcoming particles. A CMOS-based, high resolution, high radiation tolerant, and high magnetic field resistant photo-camera was mounted inside the MEG II detector at the Paul Scherrer Institute (Switzerland). MEG II is used to search for lepton flavor violation in muon decays. The photogrammetric method's challenges, affecting measurements of low momentum particles' tracks, are the high magnetic field of the spectrometer, high radiation levels, tight space constraints, and the need to limit the material budget in the tracking volume. The camera is focused on the dot pattern drawn on the thin MEG II target, about 1 m away from the detector endcaps where the photo-camera is placed. Target movements and deformations are monitored by comparing images of the dots taken at various times during the measurement. The images are acquired with a Raspberry board and analyzed using custom software. Global alignment to the spectrometer is guaranteed by corner cubes placed on the target support. As a result, the target monitoring fulfills the needs of the experiment.

3.
Nano Lett ; 16(1): 8-20, 2016 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-26666842

RESUMO

The combination of plasmonic nanoparticles and graphene enhances the responsivity and spectral selectivity of graphene-based photodetectors. However, the small area of the metal-graphene junction, where the induced electron-hole pairs separate, limits the photoactive region to submicron length scales. Here, we couple graphene with a plasmonic grating and exploit the resulting surface plasmon polaritons to deliver the collected photons to the junction region of a metal-graphene-metal photodetector. This gives a 400% enhancement of responsivity and a 1000% increase in photoactive length, combined with tunable spectral selectivity. The interference between surface plasmon polaritons and the incident wave introduces new functionalities, such as light flux attraction or repulsion from the contact edges, enabling the tailored design of the photodetector's spectral response. This architecture can also be used for surface plasmon biosensing with direct-electric-redout, eliminating the need of bulky optics.


Assuntos
Técnicas Biossensoriais , Grafite/química , Metais/química , Nanopartículas/química , Luz , Nanotecnologia/métodos , Fótons , Ressonância de Plasmônio de Superfície
4.
Nano Lett ; 14(7): 3733-42, 2014 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-24884339

RESUMO

Graphene's high mobility and Fermi velocity, combined with its constant light absorption in the visible to far-infrared range, make it an ideal material to fabricate high-speed and ultrabroadband photodetectors. However, the precise mechanism of photodetection is still debated. Here, we report wavelength and polarization-dependent measurements of metal-graphene-metal photodetectors. This allows us to quantify and control the relative contributions of both photothermo- and photoelectric effects, both adding to the overall photoresponse. This paves the way for a more efficient photodetector design for ultrafast operating speeds.

5.
In. G�lvez Gonz�lez, Ana Maria; Garc�a Fari�as, Anai. Resultados de investigaci�n en econom�a de la salud. La Habana, Ecimed, 2014. , tab, graf.
Monografia em Espanhol | CUMED | ID: cum-56671
6.
Opt Express ; 21(20): 23261-71, 2013 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-24104240

RESUMO

We demonstrate a mid-infrared Raman-soliton continuum extending from 1.9 to 3 µm in a highly germanium-doped silica-clad fiber, pumped by a nanotube mode-locked thulium-doped fiber system, delivering 12 kW sub-picosecond pulses at 1.95 µm. This simple and robust source of light covers a portion of the atmospheric transmission window.

7.
Nat Commun ; 4: 1987, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23770933

RESUMO

Graphene is emerging as a viable alternative to conventional optoelectronic, plasmonic and nanophotonic materials. The interaction of light with charge carriers creates an out-of-equilibrium distribution, which relaxes on an ultrafast timescale to a hot Fermi-Dirac distribution, that subsequently cools emitting phonons. Although the slower relaxation mechanisms have been extensively investigated, the initial stages still pose a challenge. Experimentally, they defy the resolution of most pump-probe setups, due to the extremely fast sub-100 fs carrier dynamics. Theoretically, massless Dirac fermions represent a novel many-body problem, fundamentally different from Schrödinger fermions. Here we combine pump-probe spectroscopy with a microscopic theory to investigate electron-electron interactions during the early stages of relaxation. We identify the mechanisms controlling the ultrafast dynamics, in particular the role of collinear scattering. This gives rise to Auger processes, including charge multiplication, which is key in photovoltage generation and photodetectors.

8.
Opt Express ; 21(25): 31548-59, 2013 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-24514728

RESUMO

We report a versatile way of controlling the unsaturated loss, modulation depth and saturation fluence of graphene-based saturable absorbers (GSAs), by changing the thickness of a spacer between a single layer graphene (SLG) and a high-reflection mirror. This allows us to modulate the electric field intensity enhancement at the GSA from 0 up to 400%, due to the interference of incident and reflected light at the mirror. The unsaturated loss of the SLG-mirror-assembly can be reduced to ∼0. We use this to mode-lock a vertical-external-cavity surface-emitting laser (VECSEL) from 935 to 981 nm. This approach can be applied to integrate SLG into various optical components, such as output coupler mirrors, dispersive mirrors or dielectric coatings on gain materials. Conversely, it can also be used to increase the absorption (up to 10%) in various graphene based photonics and optoelectronics devices, such as photodetectors.


Assuntos
Grafite/química , Lasers , Lentes , Refratometria/instrumentação , Desenho de Equipamento , Análise de Falha de Equipamento , Integração de Sistemas
9.
J Pers Soc Psychol ; 49(6): 1728-37, 1985 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-4087144

RESUMO

This experiment examined an interpersonal-process view of depression by assessing subjects' reactions to a request for help from a hypothetical depressed or nondepressed person with whom they had been acquainted for a relatively short (2 weeks) or long (1 year) period of time. Subjects responded to each of the four hypothetical persons by indicating their probable affective reactions to the request, the number of minutes they would be willing to help, their desire for future social contact with the hypothetical person, and their expectations of future requests for help. Requests from depressed persons elicited significantly more anger and social rejection but equal amounts of concern and willingness to help. This mixed response pattern was interpreted as providing partial support for an interpersonal-process view of depression. In addition a path analysis provided limited support for Coyne's (1976b) hypothesis that rejection of depressed persons results from the negative mood they induce in others.


Assuntos
Transtorno Depressivo/psicologia , Comportamento de Ajuda , Relações Interpessoais , Adulto , Humanos , Testes Psicológicos , Desejabilidade Social
10.
Bilt Hematol Transfuz ; 12(2): 59-63, 1984.
Artigo em Servo-Croata (Latino) | MEDLINE | ID: mdl-6525165

RESUMO

The work presents classical form and variant of F XII deficiency. Although a rare disorder, F XII deficiency can lead to bleeding, particularly after injuries and surgeries. Further laboratory investigation of patients with pathological APTT is required.


Assuntos
Deficiência do Fator XII , Adulto , Pré-Escolar , Feminino , Humanos , Masculino
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