28,769 research outputs found

    Fluorides, orthodontics and demineralization: a systematic review

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    Objectives: To evaluate the effectiveness of fluoride in preventing white spot lesion (WSL) demineralization during orthodontic treatment and compare all modes of fluoride delivery. Data sources: The search strategy for the review was carried out according to the standard Cochrane systematic review methodology. The following databases were searched for RCTs or CCTs: Cochrane Clinical Trials Register, Cochrane Oral Health Group Specialized Trials Register, MEDLINE and EMBASE. Inclusion and exclusion criteria were applied when considering studies to be included. Authors of trials were contacted for further data. Data selection: The primary outcome of the review was the presence or absence of WSL by patient at the end of treatment. Secondary outcomes included any quantitative assessment of enamel mineral loss or lesion depth. Data extraction: Six reviewers independently, in duplicate, extracted data, including an assessment of the methodological quality of each trial. Data synthesis: Fifteen trials provided data for this review, although none fulfilled all the methodological quality assessment criteria. One study found that a daily NaF mouthrinse reduced the severity of demineralization surrounding an orthodontic appliance (lesion depth difference –70.0 µm; 95% CI –118.2 to –21.8 µm). One study found that use of a glass ionomer cement (GIC) for bracket bonding reduced the prevalence of WSL (Peto OR 0.35; 95% CI 0.15–0.84) compared with a composite resin. None of the studies fulfilled all of the methodological quality assessment criteria. Conclusions: There is some evidence that the use of a daily NaF mouthrinse or a GIC for bonding brackets might reduce the occurrence and severity of WSL during orthodontic treatment. More high quality, clinical research is required into the different modes of delivering fluoride to the orthodontic patient

    Optimizing photon indistinguishability in the emission from incoherently-excited semiconductor quantum dots

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    Most optical quantum devices require deterministic single-photon emitters. Schemes so far demonstrated in the solid state imply an energy relaxation which tends to spoil the coherent nature of the time evolution, and with it the photon indistinguishability. We focus our theoretical investigation on semiconductor quantum dots embedded in microcavities. Simple and general relations are identified between the photon indistinguishability and the collection efficiency. The identification of the key parameters and of their interplay provides clear indications for the device optimization

    Peran Syaikh Nawawi Al-Bantani dalam Penyebaran Islam di Nusantara

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    Indonesia is a country known has Islamic spacious, has a famous scholar and intellectuals in the world, especially in the Indonesian archipelago. Success in the deployment of the symbols of Islam in the archipelago that cannot be separated from the active role of earlier scholars who actively spread Islam in the archipelago, especially in Indonesia. This research aim to describe an outstanding figure of scholar whose name is Nawawi al-Bantani. He is a prominent figure scholar of Da'wah or Rijal al-Da'wah sizable his services for the development and spreading the Da'wah Islamiyah in his native country (Indonesia) as well as in the Islamic world. The role and activities of Da'wah can be seen by teachings of Islam through education in Mekah al-Mukarramah, with the success of his students who went on to become leader of Da'wah in spreading Islam in the archipelago, also through writing which they scattered everywhere so that it becomes a source and a reference to the present time

    Reverse graded relaxed buffers for high Ge content SiGe virtual substrates

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    An innovative approach is proposed for epitaxial growth of high Ge content, relaxed Si1−xGex buffer layers on a Si(001) substrate. The advantages of the technique are demonstrated by growing such structures via chemical vapor deposition and their characterization. Relaxed Ge is first grown on the substrate followed by the reverse grading approach to reach a final buffer composition of 0.78. The optimized buffer structure is only 2.8 µm thick and demonstrates a low surface threading dislocation density of 4×106 cm−2, with a surface roughness of 2.6 nm. The buffers demonstrate a relaxation of up to 107%
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