86 research outputs found

    Silicon-Bridged donor-acceptor compounds: synthesis and nonlinear optical properties

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    This thesis describes the synthesis and the spectroscopic and nonlinear optical characterization of a large series of donor- and acceptor-substituted diphenylsilanes with the structure DPh-(SiMez).-PhA and fragments thereof. Nonlinear optics (NLO) deals with the interaction of electromagnetic fields (light) with matter so as to generate new electromagnetic fields altered from the incident field with respect to phase, frequency, amplitude or other propagation characteristics. One of the applications involving nonlinear optical phenomena is frequency doubling of near infrared laser light (frequency a) by a nonlinear optical material into blue light. ... Zie: Summery

    Artificial coherent states of light by multi-photon interference in a single-photon stream

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    Coherent optical states consist of a quantum superposition of different photon number (Fock) states, but because they do not form an orthogonal basis, no photon number states can be obtained from it by linear optics. Here we demonstrate the reverse, by manipulating a random continuous single-photon stream using quantum interference in an optical Sagnac loop, we create engineered quantum states of light with tunable photon statistics, including approximate weak coherent states. We demonstrate this experimentally using a true single-photon stream produced by a semiconductor quantum dot in an optical microcavity, and show that we can obtain light with g(2)(0)1g^{(2)}(0)\rightarrow1 in agreement with our theory, which can only be explained by quantum interference of at least 3 photons. The produced artificial light states are, however, much more complex than coherent states, containing quantum entanglement of photons, making them a resource for multi-photon entanglement.Comment: 6 pages + supplemental materia

    Randomized multicenter trial on percutaneous versus open access in endovascular aneurysm repair (PiERO).

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    BACKGROUND: In endovascular valve and aortic repair, vascular access through a percutaneous approach has become the competing technique to an open surgical approach. The effect on postoperative complications and surgical site infections (SSIs) has been investigated, but randomized evidence is lacking. The objective was to investigate whether percutaneous access of the common femoral artery (CFA) with a percutaneous closure device would decrease the number of SSIs compared with open surgical access of the CFA in endovascular aneurysm repair (EVAR). METHODS: Patients with an abdominal aortic aneurysm suitable for EVAR were randomized to open or percutaneous access of the main device (MD) through the CFA. Through the contralateral side, access was obtained with the other technique than the one for which the MD was randomized. The primary outcome was number of SSIs. Secondary outcomes were wound complications, visual analog scale for pain scores, and standardized wound assessment scores during follow-up. Preoperative screening culture and groin biopsy specimens were obtained from all patients. RESULTS: Both groups contained 137 groins. SSI rate was 1.5% in the open group vs 0% in the percutaneous group. For MDs only, SSI rate was 3.1% (odds ratio, 3.3; 95% confidence interval, 0.31-347; P = .34). Wound complications were comparable in both groups. Neither nasal nor groin Staphylococcus aureus carriage had a significant effect on SSIs, Southampton Wound Assessment score, or visual analog scale score. Adjusted pain score was 0.69 lower, in favor of percutaneous access. Wound assessment was better after 2 weeks (odds ratio, 3.57; 95% confidence interval, 1.02-12.44; P = .046), also in favor of percutaneous access. CONCLUSIONS: Percutaneous access of the CFA does not reduce the number of SSIs. It does, however, reduce pain and improve wound healing with less inflammation 1 day and 2 weeks after EVAR, respectively

    A comparison of three treatment strategies in recent onset non-systemic Juvenile Idiopathic Arthritis: Initial 3-months results of the BeSt for Kids-study

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    Background: Combination therapy with prednisone or etanercept may induce earlier and/or more improvement in disease activity in Disease Modifying Anti Rheumatic Drug (DMARD) naïve non-systemic Juvenile Idiopathic Arthritis (JIA) patients. Here we present three months clinical outcome of initial treatments of the BeSt-for-Kids study. Methods: Included patients were randomized to either: 1. initial DMARD-monotherapy (sulfasalazine (SSZ) or methotrexate (MTX)), 2. Initial MTX / prednisolone-bridging, 3. Initial combination MTX/etanercept. Percentage inactive disease, adjusted (a) ACR Pedi30, 50 and 70 and JADAS after 6 and 12 weeks of treatment (intention to treat analysis) and side effects are reported. Results: 94 patients (67% girls, 32 (arm 1), 32 (arm 2) and 30 (arm 3) with median (InterQuartileRange) age of 9.1 (4.7-12.9) years were included. 38% were ANA positive, 10 had oligo-articular disease, 68 polyarticular JIA and 16 psoriatic arthritis. Baseline median (IQR) ACRpedi-scores: VAS physician 49 (40-58) mm, VAS patient 54 (37-70) mm, ESR 6.5 (2-14.8)mm/hr, active joint count 8 (5-12), limited joint count 3 (1-5), CHAQ score 0.88 (0.63-1.5). In arm 1, 17 started with MTX, 15 with SSZ. After 3 months, aACR Pedi 50 was reached by 10/32 (31%), 12/32(38%) and 16/30 (53%) (p = 0.19) and aACR Pedi 70 was reached by 8/32 (25%), 6/32(19%) and 14/30(47%) in arms 1-3 (p = 0.04). Toxicity was similar. Few serious adverse events were reported. Conclusion: After 3 months of treatment in a randomized trial, patients with recent-onset JIA achieved significantly more clinical improvement (aACRPedi70) on initial combination therapy with MTX / etanercept than on initial MTX or SSZ monotherapy. Trial registration:NTR1574. Registered 3 December 2008

    The effects of TNF-alpha inhibitor therapy on the incidence of infection in JIA children

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    Juvenile Idiopathic arthritis (JIA) is the most common chronic rheumatic disease in childhood. The diagnosis is based on the underlying symptoms of arthritis with an exclusion of other diseases Biologic agents are increasingly used on the side of disease-modifying anti-rheumatic drugs (DMARD) in JIA treatment.The aim of this meta-analysis was to investigate the observed infections in JIA children during tumor necrosis factor (TNF)-alpha inhibitor therapy. A systematic search of three databases (Medline via PubMed, Embase, Cochrane Library) was carried out up to May 2018. Published trials that evaluated the infectious adverse events in patients receiving TNF-alpha inhibitor vs. a control group were included in the analysis. Full-text data extraction was carried out independently by the investigators from ten relevant publications. 1434 patients received TNF-alpha inhibitor therapy; the control group consisted of 696 subjects. The analysis presented the risk of infection in the active treatment group (OR = 1.13; 95% CI: 0.76-1.69; p = 0.543). The majority of infections were upper respiratory tract infections (URTIs). Furthermore, the subgroup analysis demonstrated a higher infection rate in the observed localization.Anti-TNF therapy slightly but not significantly increases the incidence of infection in JIA children compared to other therapies (GRADE: moderate evidence). The most common infections reported were mild URTIs. Further studies with larger patients number with a strong evidence level are crucially needed to finalize the answer whether anti-TNF therapy elevates and if yes on what extent the incidence of infection in JIA children.Prospero: CRD42017067873

    Preliminary announcement of the first International Congress of Soil Science

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    SYNTHESIS AND CRYSTAL-STRUCTURE OF PARASUBSTITUTED DIPHENYLSILANES OF INTEREST FOR NONLINEAR OPTICS - SULFONYL ACCEPTOR GROUPS

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    Donor-acceptor substituted diphenylsilanes have been synthesized because of their nonlinear optical properties. The crystal and molecular structure of disilanes having a dimethylamino donor and a sulfonyl containing acceptor are described for the first time. These molecules have a trans-type conformation. The geometries of the acceptors reflect their distinct electron-withdrawing character. Strong electron conjugation between the phenyl ring and the dimethylamino donor, which is almost sp2 hybridized, is indicated. The structural data form a useful basis for the analysis of molecular properties, obtained experimentally or predicted by calculations.</p
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