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For photon-counting applications at ultraviolet wavelengths, there are currently no detectors that combine high efficiency (> 50%), sub-nanosecond timing resolution, and sub-Hz dark count rates. Superconducting nanowire single-photon detectors (SNSPDs) have seen success over the past decade for photon-counting applications in the near-infrared, but little work has been done to optimize SNSPDs for wavelengths below 400 nm. Here, we describe the design, fabrication, and characterization of UV SNSPDs operating at wavelengths between 250 and 370 nm. The detectors have active areas up to 56 µm in diameter, 70 - 80% efficiency at temperatures up to 4.2 K, timing resolution down to 60 ps FWHM, blindness to visible and infrared photons, and dark count rates of â¼ 0.25 counts/hr for a 56 µm diameter pixel. These performance metrics make UV SNSPDs ideal for applications in trapped-ion quantum information processing, lidar studies of the upper atmosphere, UV fluorescent-lifetime imaging microscopy, and photon-starved UV astronomy.
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We propose and experimentally demonstrate a novel approach to a heralded single-photon source based on spectral multiplexing (SMUX) and feed-forward-based spectral manipulation of photons created by means of spontaneous parametric down-conversion in a periodically poled LiNbO_{3} crystal. As a proof of principle, we show that our three-mode SMUX increases the heralded single-photon rate compared to that of the individual modes without compromising the quality of the emitted single photons. We project that by adding further modes, our approach can lead to a deterministic single-photon source.
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We report on MoSi SNSPDs which achieved high system detection efficiency (87.1 ± 0.5% at 1542 nm) at 0.7 K and we demonstrate that these detectors can also be operated with saturated internal efficiency at a temperature of 2.3 K in a Gifford-McMahon cryocooler. We measured a minimum system jitter of 76 ps, maximum count rate approaching 10 MHz, and polarization dependence as low as 3.3 ± 0.1%. The performance of MoSi SNSPDs at 2.3 K is similar to the performance of WSi SNSPDs at < 1 K. The higher operating temperature of MoSi SNSPDs makes these devices promising for widespread use due to the simpler and less expensive cryogenics required for their operation.
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We propose and experimentally realize a novel versatile protocol that allows the quantum state engineering of heralded optical coherent-state superpositions. This scheme relies on a two-mode squeezed state, linear mixing, and a n-photon detection. It is optimally using expensive non-Gaussian resources to build up only the key non-Gaussian part of the targeted state. In the experimental case of a two-photon detection based on high-efficiency superconducting nanowire single-photon detectors, the freely propagating state exhibits a 67% fidelity with a squeezed even coherent-state superposition with a size |α|(2)=3. The demonstrated procedure and the achieved rate will facilitate the use of such superpositions in subsequent protocols, including fundamental tests and optical hybrid quantum information implementations.
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We experimentally demonstrate a high-efficiency Bell state measurement for time-bin qubits that employs two superconducting nanowire single-photon detectors with short dead-times, allowing projections onto two Bell states, |ψâ»ã and |ψâºã. Compared to previous implementations for time-bin qubits, this yields an increase in the efficiency of Bell state analysis by a factor of thirty.
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BACKGROUND: Cyclosporine A (CsA) is one of the systemic therapeutic options for moderate-to-severe psoriasis, based on its efficacy and rapidity of action. The current study investigated the response to CsA in patients with moderate-to-severe plaque psoriasis. MATERIALS AND METHODS: TRANSITION was an observational, cross-sectional, multicentre study which evaluated the proportion of partial- and suboptimal-responders among patients with moderate-to-severe plaque psoriasis treated with continuous CsA for ≥12 weeks. Patients demonstrating a Psoriasis Area and Severity Index (PASI) response of ≥90, ≥75 and <90, ≥50 and <75 and <50 were defined as responders, suboptimal-responders, partial-responders, and non-responders, respectively. RESULTS: A total of 196 patients (mean age, 46.6 years; 62.8% males) from 14 sites in Italy were evaluated. At the study visit, the mean (SD) PASI score was 4.2(5.5) compared with 15.3(7.1) prior to the last CsA cycle. For response categories, 39.8%, 22.4%, 16.8%, and 20.9% of patients were responders, suboptimal-responders, partial-responders, and non-responders to CsA treatment. Overall, 28.6% of patients permanently discontinued treatment with CsA (lack of efficacy [10.2%], poor tolerability and voluntary discontinuation [3.6% each], and other [11.7%]). CONCLUSION: Patients were only partially satisfied with CsA treatment, reporting measurable impact on quality of life. Only 40% patients showed a satisfactory response to CsA.
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Ciclosporina , Psoríase , Estudos Transversais , Ciclosporina/uso terapêutico , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Psoríase/tratamento farmacológico , Qualidade de Vida , Índice de Gravidade de Doença , Resultado do TratamentoRESUMO
We demonstrate high-performance nanowire superconducting single photon detectors (SSPDs) on bN thin films grown at a temperature compatible with monolithic integration. NbN films ranging from 150 nm to 3 nm in thickness were deposited by dc magnetron sputtering on MgO substrates at 400 degrees C SSPDs were fabricated on high quality NbN films of different thickness (7 to 3 nm) deposited under optimal conditions. Electrical and optical characterizations were performed on the SSPDs. The highest QE value measured at 4.2K is 20% at 1300 nm.
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Óxido de Magnésio/química , Óxido de Magnésio/efeitos da radiação , Nanotubos/química , Nanotubos/efeitos da radiação , Nióbio/química , Óptica e Fotônica/instrumentação , Transdutores , Temperatura Baixa , Condutividade Elétrica , Desenho de Equipamento , Análise de Falha de Equipamento , Nanotecnologia/instrumentação , Sensibilidade e EspecificidadeRESUMO
There are both fundamental and practical motivations for studying whether quantum entanglement can exist in macroscopic systems. However, multiparty entanglement is generally fragile and difficult to quantify. Dicke states are multiparty entangled states where a single excitation is delocalized over many systems. Building on previous work on quantum memories for photons, we create a Dicke state in a solid by storing a single photon in a crystal that contains many large atomic ensembles with distinct resonance frequencies. The photon is re-emitted at a well-defined time due to an interference effect analogous to multi-slit diffraction. We derive a lower bound for the number of entangled ensembles based on the contrast of the interference and the single-photon character of the input, and we experimentally demonstrate entanglement between over two hundred ensembles, each containing a billion atoms. We also illustrate the fact that each individual ensemble contains further entanglement.Multipartite entanglement is of both fundamental and practical interest, but is notoriously difficult to witness and characterise. Here, Zarkeshian et al. demonstrate multipartite entanglement in an atomic frequency comb storing a single photon in a Dicke state spread over a macroscopic ensemble.
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The objective of this study was to demonstrate the correlation between endodontic treatment on maxillary teeth and fungus ball with inductively coupled plasma mass spectrometry measurement of zinc and other metals (barium, lead and copper) in fungus ball samples. Samples of normal maxillary mucosa were used as comparison. Metal concentration was also measured in several endodontic materials. A significant difference was found between the concentration of zinc and copper in fungus ball compared to normal mucosa. Metal distribution was more similar in fungus ball and in the endodontic materials tested than normal mucosa. The similar metal concentration in the endodontic materials and fungus ball suggests that endodontic materials play a role in the pathogenesis of fungus ball. Endodontic materials accidentally pushed into the maxillary sinus during endodontic treatments may play a crucial role. Dentists should be as careful as possible when treating maxillary teeth to avoid perforating the maxillary sinus floor; the use of zinc-free endodontic materials, as zinc is a metal that plays a pivotal role in fungus growth, should be encouraged.
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Alternariose/induzido quimicamente , Aspergilose/induzido quimicamente , Materiais Restauradores do Canal Radicular/efeitos adversos , Óxido de Zinco/efeitos adversos , Humanos , Estudos Prospectivos , Fatores de RiscoRESUMO
OBJECTIVE: To examine the characteristics of thymoma when associated with MG and to evaluate those conditions that can complicate management and affect survival. METHODS: The study includes 207 myasthenic patients who were operated on for thymoma, with at least 1-year follow-up from surgery. MG severity and response to treatment, the occurrence of paraneoplastic diseases and extrathymic malignancies, thymoma histologic types and stages, adjuvant therapy, tumor recurrences, and causes of death were recorded. RESULTS: MG-associated thymoma was predominantly of B type and was invasive in the majority of patients. MG was generally severe, and most patients remained dependent on immunosuppressive therapy. Other paraneoplastic disorders and extrathymic malignancies were found in 9.66 and 11.11% of patients. Thymoma recurrences occurred in 18 of 115 patients with invasive tumors (15.65%) and were often associated with the onset/aggravation of autoimmune diseases. On completion of the study, MG and thymoma accounted for a similar mortality rate. CONCLUSIONS: Thymoma should be considered as a potentially malignant tumor requiring prolonged follow-up. The presence of myasthenic weakness can still complicate its management. Thymoma-related deaths are bound to outnumber those due to MG in the future.
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Miastenia Gravis/patologia , Timoma/patologia , Neoplasias do Timo/patologia , Adolescente , Adulto , Idoso , Causas de Morte , Criança , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Miastenia Gravis/complicações , Miastenia Gravis/mortalidade , Recidiva Local de Neoplasia , Estadiamento de Neoplasias , Estudos Retrospectivos , Timectomia , Timoma/complicações , Timoma/cirurgia , Neoplasias do Timo/complicações , Neoplasias do Timo/cirurgia , Resultado do TratamentoRESUMO
Morphologic findings of thymuses from 32 anti-acetylcholine receptor (AChR)-negative myasthenia gravis patients, 12 with and 20 without antibodies against the muscle-specific kinase (MuSK), were compared with those from 30 AChR-positive subjects. In contrast with the high frequency of thymic hyperplastic changes in AChR-positive patients, in MuSK-positive subjects histologic alterations were minimal, arguing against an intrathymic disease pathogenesis. Since hyperplastic changes were seen in 35% of MuSK-negative patients, the thymus could be involved in some of these cases.