453 research outputs found

    Recent developments in monolithic integration of InGaAsP/InP optoelectronic devices

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    Monolithically integrated optoelectronic circuits combine optical devices such as light sources (injection lasers and light emitting diodes) and optical detectors with solid-state semiconductor devices such as field effect transistors, bipolar transistors, and others on a single semiconductor crystal. Here we review some of the integrated circuits that have been realized and discuss the laser structures suited for integration with emphasis on the InGaAsP/InP material system. Some results of high frequency modulation and performance of integrated devices are discussed

    Milei dabot

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    Copia digital. Madrid : Ministerio de Cultura. Subdirección General de Coordinación Bibliotecaria, 2011Fecha en port.: 5668SignaturizadoPort. con orla litogr

    The miR-17 similar to 92 cluster collaborates with the Sonic Hedgehog pathway in medulloblastoma

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    Medulloblastomas (MBs) are the most common brain tumors in children. Some are thought to originate from cerebellar granule neuron progenitors (GNPs) that fail to undergo normal cell cycle exit and differentiation. Because microRNAs regulate numerous aspects of cellular physiology and development, we reasoned that alterations in miRNA expression might contribute to MB. We tested this hypothesis using 2 spontaneous mouse MB models with specific initiating mutations, Ink4c(-/-); Ptch1(+/-) and Ink4c(-/-); p53(-/-). We found that 26 miRNAs showed increased expression and 24 miRNAs showed decreased expression in proliferating mouse GNPs and MBs relative to mature mouse cerebellum, regardless of genotype. Among the 26 overexpressed miRNAs, 9 were encoded by the miR-17 similar to 92 cluster family, a group of microRNAs implicated as oncogenes in several tumor types. Analysis of human MBs demonstrated that 3 miR-17 similar to 92 cluster miRNAs (miR-92, miR-19a, and miR-20) were also overexpressed in human MBs with a constitutively activated Sonic Hedgehog (SHH) signaling pathway, but not in other forms of the disease. To test whether the miR-17 similar to 92 cluster could promote MB formation, we enforced expression of these miRNAs in GNPs isolated from cerebella of postnatal (P) day P6 Ink4c(-/-); Ptch1(+/-) mice. These, but not similarly engineered cells from Ink4c(-/-); p53(-/-) mice, formed MBs in orthotopic transplants with complete penetrance. Interestingly, orthotopic mouse tumors ectopically expressing miR-17 similar to 92 lost expression of the wild-type Ptch1 allele. Our findings suggest a functional collaboration between the miR-17 similar to 92 cluster and the SHH signaling pathway in the development of MBs in mouse and man

    Mode stabilization mechanism of buried-waveguide lasers with lateral diffused junctions

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    The mode stabilization behavior of the buried active waveguide with lateral diffused junction is theoretically investigated. The study shows that for an active waveguide of width around 5 μm with a lateral diffused junction in the middle, the single fundamental transverse mode is preferred as the injection level is raised. The theoretical results are found to be in good agreement with experimental results observed in the groove transverse junction InGaAsP/InP laser

    Rapid and Sustained Long-Term Efficacy and Safety of Canakinumab in Patients With Cryopyrin-Associated Periodic Syndrome Ages Five Years and Younger.

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    To assess long-term efficacy and safety of canakinumab and the response to vaccination in children ages ≤5 years with cryopyrin-associated periodic syndrome (CAPS). CAPS patients (ages ≤5 years) received 2 mg/kg canakinumab subcutaneously every 8 weeks; patients with neonatal-onset multisystem inflammatory disease (NOMID) received a starting dose of 4 mg/kg in this open-label trial. Efficacy was evaluated using physician global assessment of disease activity and serum levels of C-reactive protein (CRP) and amyloid A (SAA). Adverse events (AEs) were recorded. Vaccination response was evaluated using postvaccination antibody titers at 4 and 8 weeks after immunization. Of the 17 patients enrolled, 12 (71%) had Muckle-Wells syndrome, 4 (24%) had NOMID, and 1 (6%) had familial cold autoinflammatory syndrome. All 17 patients had a complete response to canakinumab. Disease activity improved according to the physician global assessment, and for 65% of the patients autoinflammatory disease was characterized as "absent" at the end of the study. Median CRP levels decreased over time. No such change was evident in SAA levels. During the extension study, postvaccination antibody titers increased above protective levels in 16 (94%) of 17 assessable vaccinations. Ten of the patients (59%) had AEs suspected to be related to canakinumab; 8 (47%) experienced at least 1 serious AE (SAE). None of the AEs or SAEs required interruption of canakinumab therapy. Our findings indicate that canakinumab effectively maintains efficacy through 152 weeks and appears to have no effect on the ability to produce antibodies against standard childhood non-live vaccines. The safety profile of canakinumab was consistent with previous studies, supporting long-term use of canakinumab for CAPS in children ≤5 years of age

    Anisotropic flow at RHIC: How unique is the number-of-constituent-quark scaling?

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    The transverse momentum dependence of the anisotropic flow v2v_2 for π\pi, KK, nucleon, Λ\Lambda, Ξ\Xi and Ω\Omega is studied for Au+Au collisions at sNN=200\sqrt{s_{\rm NN}} = 200 GeV within two independent string-hadron transport approaches (RQMD and UrQMD). Although both models reach only 60% of the absolute magnitude of the measured v2v_2, they both predict the particle type dependence of v2v_2, as observed by the RHIC experiments: v2v_2 exhibits a hadron-mass hierarchy (HMH) in the low pTp_T region and a number-of-constituent-quark (NCQ) dependence in the intermediate pTp_T region. The failure of the hadronic models to reproduce the absolute magnitude of the observed v2v_2 indicates that transport calculations of heavy ion collisions at RHIC must incorporate interactions among quarks and gluons in the early, hot and dense phase. The presence of an NCQ scaling in the string-hadron model results suggests that the particle-type dependencies observed in heavy-ion collisions at intermediate pTp_T might be related to the hadronic cross sections in vacuum rather than to the hadronization process itself.Comment: 10 pages, 5 figures; A new author (H. Petersen) is added; A new figure (fig.1) on time evolution of elliptic flow and number of collisions is added; Version accepted for publication in J. Phys.

    Tibial torus and toddler's fractures misdiagnosed as transient synovitis: a case series

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    <p>Abstract</p> <p>Introduction</p> <p>The high incidence of transient synovitis in early childhood makes it the first suspected pathology in a limping child. Trauma, which has long been regarded as a causative factor for transient synovitis, may be underestimated in a non-cooperative toddler.</p> <p>After excluding most serious conditions, such as septic arthritis, a speculative diagnosis of transient synovitis can be made, and this can easily mask a subtle musculoskeletal injury.</p> <p>Case presentations</p> <p>We report the cases of three Caucasian patients (two boys, aged 20-months- and three-years-old, and one girl, aged two-years-old), with tibial torus and toddler's fractures which were late-diagnosed due to an initial misdiagnosis of transient synovitis of the hip.</p> <p>Conclusion</p> <p>In a non-cooperative child musculoskeletal trauma can be mistaken as a simple causative factor for transient synovitis of the hip and this can easily prevent further investigation for a possible subtle musculoskeletal injury of the lower extremities.</p> <p>Our experience with the presented cases suggests the need to be more vigilant in the differential diagnosis of transient synovitis in young children.</p
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