62 research outputs found

    Focused ion beam milling of diamond waveguides

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    Design of weak 1-D bragg grating filters in SOI waveguides using volume holography techniques

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    To answer the growing need for more versatile integrated spectral filters, we show that weak one-dimensional gratings can be designed towards any desired target spectrum. We follow a very straightforward design procedure to demonstrate the performance of these devices. Measurements and simulations show a very good correspondence with the target spectra. By analyzing the results, we also found that the design procedure can be refined by using simulated reflections, instead of relying on the calculated Fresnel reflections

    Grating couplers in ultrananocrystalline diamond

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    Grating couplers and waveguides were fabricated in a thin layer of ultrananocrystalline diamond with a focused-ion-beam. The measured spectra were linked to simulations to estimate material-related propagation losses

    Weak gratings in silicon-on-insulator for spectral filters based on volume holography

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    We demonstrate integrated holographic grating filters, that can be designed toward any desired target spectrum. A straightforward design method transforms this target spectrum into a weak effective refractive index variation. The filters are implemented in high-contrast silicon-on-insulator by modulating the width of the shallow etched sides of a ridge waveguide. Measurements show that this is a promising approach to integrate flexible and versatile filters on photonic chips to enable more complex applications. © 2013 Optical Society of America OCIS codes: 130.7408, 050.0050, 090.7330. Silicon-on-insulator (SOI) has emerged as a popular platform for photonic integrated circuits, mainly because of its high refractive index contrast and its compatibility with complementary metal oxide semiconductor fabrica-tion technology [1]. As the latter technology becomes even more refined, more functionality and complexity can be added to the photonic chips. This creates a need for more flexible and versatile spectral filters. Filters based on photonic crystals, arrayed waveguid

    Percutaneous cementoplasty in multiple myeloma: a valuable adjunct for pain control and ambulation maintenance

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    Goals of work: Bone pain and functional impairment are major concerns for multiple myeloma (MM) patients. The goal of this study was to better define the role of percutaneous cementoplasty (PC) in improving their quality of life. Materials and methods: This retrospective analysis included 28 consecutive heavily pretreated MM patients managed at our institution between 1996 and 2002. They underwent a total of 34 PC procedures for the treatment of 117 vertebrae and 2 iliac sites and were evaluated at 1month. Main results: Significant pain reduction of >50% was obtained after 83% of the procedures, with a mean visual analogous score decreasing from 7.48/10 to 2.1/10 (p < 0.001). It resulted in a complete interruption of opiate analgesic consumption after 59.3% of the procedures, with a mean decrease of 70.4% in the opiate dose. Functional impairment was evaluated with the Eastern Cooperative Oncology Group (ECOG) performance status scale, with mean scores improving from 1.9 to 0.86 after the procedures (p = 0.001). There was no major complication. Conclusion: PC is a safe, feasible, and efficient approach for the treatment of bone pain and disability in MM patient

    Randomised pharmacokinetic trial of rifabutin with lopinavir/ritonavir-antiretroviral therapy in patients with HIV-associated tuberculosis in Vietnam.

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    BACKGROUND: Rifampicin and protease inhibitors are difficult to use concomitantly in patients with HIV-associated tuberculosis because of drug-drug interactions. Rifabutin has been proposed as an alternative rifamycin, but there is concern that the current recommended dose is suboptimal. The principal aim of this study was to compare bioavailability of two doses of rifabutin (150 mg three times per week and 150 mg daily) in patients with HIV-associated tuberculosis who initiated lopinavir/ritonavir-based antiretroviral therapy in Vietnam. Concentrations of lopinavir/ritonavir were also measured. METHODS: This was a randomized, open-label, multi-dose, two-arm, cross-over trial, conducted in Vietnamese adults with HIV-associated tuberculosis in Ho Chi Minh City (Clinical trial registry number NCT00651066). Rifabutin pharmacokinetics were evaluated before and after the introduction of lopinavir/ritonavir -based antiretroviral therapy using patient randomization lists. Serial rifabutin and 25-O-desacetyl rifabutin concentrations were measured during a dose interval after 2 weeks of rifabutin 300 mg daily, after 3 weeks of rifabutin 150 mg daily with lopinavir/ritonavir and after 3 weeks of rifabutin 150 mg three times per week with lopinavir/ritonavir. RESULTS: Sixteen and seventeen patients were respectively randomized to the two arms, and pharmacokinetic analysis carried out in 12 and 13 respectively. Rifabutin 150 mg daily with lopinavir/ritonavir was associated with a 32% mean increase in rifabutin average steady state concentration compared with rifabutin 300 mg alone. In contrast, the rifabutin average steady state concentration decreased by 44% when rifabutin was given at 150 mg three times per week with lopinavir/ritonavir. With both dosing regimens, 2 - 5 fold increases of the 25-O-desacetyl- rifabutin metabolite were observed when rifabutin was given with lopinavir/ritonavir compared with rifabutin alone. The different doses of rifabutin had no significant effect on lopinavir/ritonavir plasma concentrations. CONCLUSIONS: Based on these findings, rifabutin 150 mg daily may be preferred when co-administered with lopinavir/ritonavir in patients with HIV-associated tuberculosis. TRIAL REGISTRATION: ClinicalTrials.gov NCT00651066

    Modelling human choices: MADeM and decision‑making

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    Research supported by FAPESP 2015/50122-0 and DFG-GRTK 1740/2. RP and AR are also part of the Research, Innovation and Dissemination Center for Neuromathematics FAPESP grant (2013/07699-0). RP is supported by a FAPESP scholarship (2013/25667-8). ACR is partially supported by a CNPq fellowship (grant 306251/2014-0)
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