144 research outputs found

    Electrically Switchable Photonic Molecule Laser

    Full text link
    We have studied the coherent intercavity coupling of the evanescent fields of the whispering gallery modes of two terahertz quantum-cascade lasers implemented as microdisk cavities. The electrically pumped single-mode operating microcavities allow to electrically control the coherent mode coupling for proximity distances of the cavities up to 30-40 \mu\m. The optical emission of the strongest coupled photonic molecule can be perfectly switched by the electrical modulation of only one of the coupled microdisks. The threshold characteristics of the strongest coupled photonic molecule demonstrates the linear dependence of the gain of a quantum-cascade laser on the applied electric field.Comment: 4 pages, 4 figure

    Systematic review of antiepileptic drugs’ safety and effectiveness in feline epilepsy

    Get PDF
    Understanding the efficacy and safety profile of antiepileptic drugs (AEDs) in feline epilepsy is a crucial consideration for managing this important brain disease. However, there is a lack of information about the treatment of feline epilepsy and therefore a systematic review was constructed to assess current evidence for the AEDs’ efficacy and tolerability in cats. The methods and materials of our former systematic reviews in canine epilepsy were mostly mirrored for the current systematic review in cats. Databases of PubMed, CAB Direct and Google scholar were searched to detect peer-reviewed studies reporting efficacy and/or adverse effects of AEDs in cats. The studies were assessed with regards to their quality of evidence, i.e. study design, study population, diagnostic criteria and overall risk of bias and the outcome measures reported, i.e. prevalence and 95% confidence interval of the successful and affected population in each study and in total

    Microcavity-integrated graphene photodetector

    Get PDF
    There is an increasing interest in using graphene (1, 2) for optoelectronic applications. (3-19) However, because graphene is an inherently weak optical absorber (only ≈2.3% absorption), novel concepts need to be developed to increase the absorption and take full advantage of its unique optical properties. We demonstrate that by monolithically integrating graphene with a Fabry-Pérot microcavity, the optical absorption is 26-fold enhanced, reaching values >60%. We present a graphene-based microcavity photodetector with responsivity of 21 mA/W. Our approach can be applied to a variety of other graphene devices, such as electro-absorption modulators, variable optical attenuators, or light emitters, and provides a new route to graphene photonics with the potential for applications in communications, security, sensing and spectroscopy

    Pre-dialysis clinic attendance improves quality of life among hemodialysis patients

    Get PDF
    BACKGROUND: Although previous research has demonstrated that referral to pre-dialysis clinics is associated with favourable objective outcomes, the benefit of a pre-dialysis clinic from the perspective of patient-perceived subjective outcomes, such as quality of life (QOL), is less well defined. METHODS: A retrospective incident cohort study was conducted to determine if pre-dialysis clinic attendance was a predictor of better QOL scores measured within the first six months of hemodialysis (HD) initiation. Inclusion criteria were HD initiation from January 1 1998 to January 1 2000, diagnosis of chronic renal failure, and completion of the QOL questionnaire within six months of HD initiation. Patients receiving HD for less than four weeks were excluded. An incident cohort of 120 dialysis patients was identified, including 74 patients who attended at least one pre-dialysis clinic and 46 patients who did not. QOL was measured using the SF 36-Item Health Survey. Independent variables included age, sex, diabetes, pre-dialysis clinic attendance and length of attendance, history of ischemic heart disease, stroke, peripheral vascular disease, heart failure, malignancy, and chronic lung disease, residual creatinine clearance at dialysis initiation, and kt/v, albumin and hemoglobin at the time of QOL assessment. Bivariate and multivariate linear regression analyses were used to identify predictors of QOL scores. RESULTS: Multivariate analysis suggested that pre-dialysis clinic attendance was an independent predictor of higher QOL scores in four of eight health domains (physical function, p < 0.01; emotional role limitation, p = 0.01; social function, p = 0.01; and general health, p = 0.03), even after statistical adjustment for age, sex, residual renal function, kt/v, albumin, and co-morbid disease. Pre-dialysis clinic attendance was also an independent predictor of the physical component summary score (p = 0.03). CONCLUSIONS: We conclude that pre-dialysis clinic attendance favourably influences patient-perceived quality of life within six months of dialysis initiation

    Development, characterization, and stability of O/W pepper nanoemulsions produced by high-pressure homogenization

    Get PDF
    Interest in the utilization of bioactive plant compounds in foods has increased due to their biochemical activities (antioxidant, antimicrobial, etc.), and as alternatives in the reduction of the use of high concentrations of chemical substances. However, some of these additives are hydrophobic, thus being harder to disperse into the food matrix, which is generally water-based. A good alternative is the use of low concentrations of these compounds as nanoemulsions. The objective of the present study was to develop oil-in-water nanoemulsions containing dedo-de-moça pepper extract for food applications. Research in the development of these nanoemulsions was carried out using a high-speed homogenizer, followed by a high-pressure homogenizer. The influence of the following parameters was assessed: type and concentration of surfactants, hidrophilic-lipophilic balance, lipid/aqueous phase ratio, surfactant/oil ratio, pepper extract composition in nanoemulsion, and processing conditions. Nanoemulsions were evaluated by environmental (centrifugal and thermal) and storage stabilities, characterized by average droplet size and -potential measurements, color, interfacial tension, atomic force, and cryo-scanning electron microscopy. Those with average droplet size between 132 ± 2.0 and 145 ± 1.0 nm were developed depending on working pressure and number of cycles; -potential was around 36.71 ± 0.62 mV and the best nanoemulsion was stable to centrifugation and most of the thermal stresses. Droplets were characterized with cryo-scanning electron microscopy as being spherical, homogeneous, and stable, and remained stable when stored at 4 °C and room temperature for over 120 days. The pepper nanoemulsion, developed in the present study, has potential applications in the food industry.The first author gratefully acknowledges the CNPq and CAPES (National Council for Scientific and Technological Development, Program Science without Boarder) for the BSWE^ PhD (Process 236877/2012-1) fellowship, and CAPES for the national PhD fellowship. The last author acknowledges the São Paulo Research Foundation (FAPESP) Brazil, for the grant (CEPID-FoRC, 2013/07914-8).info:eu-repo/semantics/publishedVersio

    Microcavity-integrated graphene photodetector

    Get PDF
    The monolithic integration of novel nanomaterials with mature and established technologies has considerably widened the scope and potential of nanophotonics. For example, the integration of single semiconductor quantum dots into photonic crystals has enabled highly efficient single-photon sources. Recently, there has also been an increasing interest in using graphene - a single atomic layer of carbon - for optoelectronic devices. However, being an inherently weak optical absorber (only 2.3 % absorption), graphene has to be incorporated into a high-performance optical resonator or waveguide to increase the absorption and take full advantage of its unique optical properties. Here, we demonstrate that by monolithically integrating graphene with a Fabry-Perot microcavity, the optical absorption is 26-fold enhanced, reaching values >60 %. We present a graphene-based microcavity photodetector with record responsivity of 21 mA/W. Our approach can be applied to a variety of other graphene devices, such as electro-absorption modulators, variable optical attenuators, or light emitters, and provides a new route to graphene photonics with the potential for applications in communications, security, sensing and spectroscopy.Comment: 19 pages, 4 figure
    • …
    corecore