384 research outputs found
Graphene-based Josephson junction single photon detector
We propose to use graphene-based Josephson junctions (gJjs) to detect single
photons in a wide electromagnetic spectrum from visible to radio frequencies.
Our approach takes advantage of the exceptionally low electronic heat capacity
of monolayer graphene and its constricted thermal conductance to its phonon
degrees of freedom. Such a system could provide high sensitivity photon
detection required for research areas including quantum information processing
and radio-astronomy. As an example, we present our device concepts for gJj
single photon detectors in both the microwave and infrared regimes. The dark
count rate and intrinsic quantum efficiency are computed based on parameters
from a measured gJj, demonstrating feasibility within existing technologies.Comment: 11 pages, 6 figures, and 1 table in the main tex
Heterodyne pump probe measurements of nonlinear dynamics in an indium phosphide photonic crystal cavity
Using a sensitive two-color heterodyne pump-probe technique, we investigate the carrier dynamics of an InP photonic crystal nanocavity. The heterodyne technique provides unambiguous results for all wavelength configurations, including the degenerate case, which cannot be investigated with the widely used homodyne technique. A model based on coupled mode theory including two carrier distributions is introduced to account for the relaxation dynamics, which is assumed to be governed by both diffusion and recombination
Demonstration of Optically Controlled re-Routing in a Photonic Crystal Three-Port Switch
We present an experimental demonstration of optically controlled re-routing of a signal in a photonic crystal cavity-waveguide structure with 3 ports. This represents a key functionality of integrated all-optical signal processing circuits
High-speed photonic crystal modulator with non-volatile memory via structurally-engineered strain concentration in a piezo-MEMS platform
Numerous applications in quantum and classical optics require scalable,
high-speed modulators that cover visible-NIR wavelengths with low footprint,
drive voltage (V) and power dissipation. A critical figure of merit for
electro-optic (EO) modulators is the transmission change per voltage, dT/dV.
Conventional approaches in wave-guided modulators seek to maximize dT/dV by the
selection of a high EO coefficient or a longer light-material interaction, but
are ultimately limited by nonlinear material properties and material losses,
respectively. Optical and RF resonances can improve dT/dV, but introduce added
challenges in terms of speed and spectral tuning, especially for high-Q
photonic cavity resonances. Here, we introduce a cavity-based EO modulator to
solve both trade-offs in a piezo-strained photonic crystal cavity. Our approach
concentrates the displacement of a piezo-electric actuator of length L and a
given piezoelectric coefficient into the PhCC, resulting in dT/dV proportional
to L under fixed material loss. Secondly, we employ a material deformation that
is programmable under a "read-write" protocol with a continuous, repeatable
tuning range of 5 GHz and a maximum non-volatile excursion of 8 GHz. In
telecom-band demonstrations, we measure a fundamental mode linewidth = 5.4 GHz,
with voltage response 177 MHz/V corresponding to 40 GHz for voltage spanning
-120 to 120 V, 3dB-modulation bandwidth of 3.2 MHz broadband DC-AC, and 142 MHz
for resonant operation near 2.8 GHz operation, optical extinction down to
min(log(T)) = -25 dB via Michelson-type interference, and an energy consumption
down to 0.17 nW/GHz. The strain-enhancement methods presented here are
applicable to study and control other strain-sensitive systems
Application of Automatic Speech Recognition Technology for Dysphonic Speech Assessment
Dysphonia is a communication disorder secondary to a problem with voice production. Speakers with dysphonia often report decreased intelligibility, particularly in a noisy communication environment. Intelligibility is the primary measure of a speaker’s communicative ability; however, it is not routinely assessed in clinical settings today. This lack of intelligibility assessment can be partly attributed to the time-consuming, labor-intensive nature of manually transcribing a speaker’s utterance. Recent advances in automatic speech recognition technology have significantly increased the ease and accuracy of speech-to-text transcription, and incorporation of this technology may dramatically increase efficiency in clinical intelligibility assessment. Therefore, this project examined the feasibility of an automatic speech-to-text transcription program for describing speech production abnormalities among speakers with dysphonia. Audio recordings of the Rainbow Passage from 30 adult female speakers with normal voice and 23 adult female speakers with dysphonic voice were transcribed using IBM Watson speech-to-text transcription service. Differences between the groups were evaluated based on three measures: 1) error rate in transcribed words, 2) confidence level of transcribed words, and 3) number of possible alternatives for transcribed words. The results indicated that the confidence level was significantly lower, and the number of possible alternatives was significantly higher in the dysphonic group. Interestingly, there was no significant between-group difference in the error rate. Clinical implications of these findings and future direction will be discussed.Ope
Exposure-Response and Population Pharmacokinetic Analyses of a Novel Subcutaneous Formulation of Daratumumab Administered to Multiple Myeloma Patients
We report the population pharmacokinetic (PK) and exposure-response analyses of a novel subcutaneous formulation of daratumumab (DARA) using data from 3 DARA subcutaneous monotherapy studies (PAVO Part 2, MMY1008, COLUMBA) and 1 combination therapy study (PLEIADES). Results were based on 5159 PK samples from 742 patients (DARA 1800 mg subcutaneously, n = 487 [monotherapy, n = 288; combination therapy, n = 199]; DARA 16 mg/kg intravenously, n = 255 [all monotherapy, in COLUMBA]; age, 33-92 years; weight, 28.6-147.6 kg). Subcutaneous and intravenous DARA monotherapies were administered once every week for cycles 1-2, once every 2 weeks for cycles 3-6, and once every 4 weeks thereafter (1 cycle is 28 days). The subcutaneous DARA combination therapy was administered with the adaptation of corresponding standard-of-care regimens. PK samples were collected between cycle 1 and cycle 12. Among monotherapy studies, throughout the treatment period, subcutaneous DARA provided similar/slightly higher trough concentrations (Ctrough) versus intravenous DARA, with lower maximum concentrations and smaller peak-to-trough fluctuations. The PK profile was consistent between subcutaneous DARA monotherapy and combination therapies. The exposure-response relationship between daratumumab PK and efficacy or safety end points was similar for subcutaneous and intravenous DARA. Although the ≤65-kg subgroup reported a higher incidence of neutropenia, no relationship was found between the incidence of neutropenia and exposure, which was attributed, in part, to the preexisting imbalance in neutropenia between subcutaneous DARA (45.5%) and intravenous DARA (19%) in patients ≤50 kg. A flat relationship was observed between body weight and any grade and at least grade 3 infections. The results support the DARA 1800-mg subcutaneous flat dose as an alternative to the approved intravenous DARA 16 mg/kg.The clinical studies and the analyses presented here were supported by research funding from Janssen Research & Development, LLC
Therapy-refractory Panton Valentine Leukocidin-positive community-acquired methicillin-sensitive Staphylococcus aureus sepsis with progressive metastatic soft tissue infection: a case report
We report a case of fulminant multiple organ failure including the Acute Respiratory Distress Syndrome (ARDS), haemodynamic, and renal failure due to community-acquired methicillin-sensitive Panton Valentine Leukocidin (PVL) positive spa-type 284 (ST121) Staphylococcus aureus septic shock. The patient's first clinical symptom was necrotizing pneumonia. Despite organism-sensitive triple antibiotic therapy with linezolid, imipenem and clindamycin from the first day of treatment, progressive abscess formation in multiple skeletal muscles was observed. As a result, repeated surgical interventions became necessary. Due to progressive soft tissue infection, the anti-microbial therapy was changed to a combination of clindamycin and daptomycin. Continued surgical and antimicrobial therapy finally led to a stabilisation of the patients' condition. The clinical course of our patient underlines the existence of a "PVL-syndrome" which is independent of in vitro Staphylococcus aureus susceptibility. The PVL-syndrome should not only be considered in patients with soft tissue or bone infection, but also in patients with pneumonia. Such a condition, which may easily be mistaken for uncomplicated pneumonia, should be treated early, aggressively and over a long period of time in order to avoid relapsing infection
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