530 research outputs found

    Study of TMDs nanosheets based saturable absorber used for Q-switching and mode lock laser system

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    Pulse width of pulsed laser determinates their applications. For the long pulse laser with µs or ns pulse width, it can be used for telecommunication, remote sensing and medical surgery. For the ultrashort pulse laser with ps or fs pulse width, it can be used for eye-surgery, precise micro- or even nano-machining on transparent material and novel 3D hologram formation. The saturable absorber (SA) is the crucial optical component that switch the laser operation from CW mode to pulse mode passively. Therefore it attract s great research interests from the laser photonic community. &more..

    Propagation characteristics and identification of type I cracks by the extended finite element method combined with modal analysis

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    Extended finite element frame based on Abaqus is applied to research the crack propagation problem of two-dimensional long rectangular thin plate. Presuppose type I crack with different horizontal locations and longitudinal dimensions, the propagation characteristics of the edge crack is discussed with the objects of structural flexibility of the thin plate, crack propagation length and plastic zone of crack tip etc. The results indicate that the horizontal location of the initial crack has a small influence on the crack propagation characteristics, and it only affects the local flexibility of the thin plate as well as the dimension and shape of plastic zone of crack tip. The longitudinal dimension of the initial crack obviously nonlinear influence on various parameters of the crack propagation characteristics. In view of the disastrous consequence of crack propagation, the vibration characteristics of the thin plate with different crack dimensions and crack locations are discussed based on the experiment and simulation modal analysis on the thin plate, thus providing basis for prior estimation and control for crack generation and propagation

    Preparation of GHZ states via Grover's quantum searching algorithm

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    In this paper we propose an approach to prepare GHZ states of an arbitrary multi-particle system in terms of Grover's fast quantum searching algorithm. This approach can be regarded as an extension of the Grover's algorithm to find one or more items in an unsorted database.Comment: 9 pages, Email address: [email protected]

    Quality of reporting of systematic reviews published in “evidence-based” Chinese journals

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    BACKGROUND: The number of systematic reviews (SRs)/meta-analyses (MAs) has increased dramatically in China over the past decades. However, evaluation of quality of reporting of systematic reviews published has not been undertaken. The objective of this study is to evaluate the quality of reporting of SRs/MAs assessing efficacy and/or harms of clinical interventions published in “evidence-based” Chinese journals. METHODS: Web-based database searches were conducted for the Chinese Journal of Evidence-based Medicine, the Journal of Evidence-Based Medicine, the Chinese Journal of Evidence Based Pediatrics, and the Chinese Journal of Evidence-Based Cardiovascular Medicine. SRs/MAs assessing efficacy and/or harms of clinical interventions were included. The cut-off was December 31st 2011. The PRISMA statement was applied to assess the quality of reporting. Each item was assessed as follows: ‘Yes’ for total compliance, scored ‘1’; ‘partial’ for partial compliance, scored ‘0.5’; and ‘No’ for non-compliance, scored ‘0’. The review was considered to have major flaws if it received a total score of ≤15.0, minor flaws if it received a total score of 15.5 to 21.0, and minimal flaws if it received a total score 21.5 to 27.0. Odds ratios were used for binary variables, and the mean difference was used for continuous variables. Analyses were performed using RevMan 5.0 software. RESULTS: Overall, 487 SRs/MAs were identified and assessed. The included reviews had medium quality with minor flaws based on PRISMA total scores (range: 8.5–26.0; mean: 19.6 ± 3.3). The stratified analysis showed that SRs/MAs with more than 3 authors, from a university, hospital + university cooperation, multiple affiliations (≥2), and funding have significantly higher quality of reporting of SRs/MAs; 58% of the included reviews were considered to have minor flaws (total score of 15.6 to 21.0). Only 9.6% of reviews were considered to have major flaws. Specific areas needing improvement in reporting include the abstract, protocol and registration, and characteristics of the search. CONCLUSIONS: The reporting of SRs published in “evidence-based” Chinese journals is poor and needs to be improved in order for reviews to be useful. SR authors should use the PRISMA checklist to ensure complete and accurate accounts of their SRs

    Coseeded Schwann cells myelinate neurites from differentiated neural stem cells in neurotrophin-3-loaded PLGA carriers

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    Biomaterials and neurotrophic factors represent promising guidance for neural repair. In this study, we combined poly-(lactic acid-co-glycolic acid) (PLGA) conduits and neurotrophin-3 (NT-3) to generate NT-3-loaded PLGA carriers in vitro. Bioactive NT-3 was released stably and constantly from PLGA conduits for up to 4 weeks. Neural stem cells (NSCs) and Schwann cells (SCs) were coseeded into an NT-releasing scaffold system and cultured for 14 days. Immunoreactivity against Map2 showed that most of the grafted cells (>80%) were differentiated toward neurons. Double-immunostaining for synaptogenesis and myelination revealed the formation of synaptic structures and myelin sheaths in the coculture, which was also observed under electron microscope. Furthermore, under depolarizing conditions, these synapses were excitable and capable of releasing synaptic vesicles labeled with FM1-43 or FM4-64. Taken together, coseeding NSCs and SCs into NT-3-loaded PLGA carriers increased the differentiation of NSCs into neurons, developed synaptic connections, exhibited synaptic activities, and myelination of neurites by the accompanying SCs. These results provide an experimental basis that supports transplantation of functional neural construction in spinal cord injury

    Phylogenetic and molecular characterization of coxsackievirus A24 variant isolates from a 2010 acute hemorrhagic conjunctivitis outbreak in Guangdong, China

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    <p>Abstract</p> <p>Background</p> <p>Acute hemorrhagic conjunctivitis is a common disease in China. As a notifiable disease, cases are registered by ophthalmologists on the AHC surveillance system. An AHC outbreak caused by CA24v was observed in Guangdong Province in 2007 by the National Disease Supervision Information Management System. Three years later, a larger outbreak occurred in Guangdong during the August-October period (2010). To characterize the outbreak and compare the genetic diversity of CA24v, which was determined to be the cause of the outbreak, the epidemiology and the molecular characterization of CA24v were analyzed in this study.</p> <p>Results</p> <p>A total of 69,635 cases were reported in the outbreak. 73.5% of index cases originated from students, children in kindergarten and factory workers, with the ≦ 9 age group at the highest risk. The male to female ratio was 1.84:1 among 0-19 years. 56 conjunctival swabs were collected to identify the causative agent from five cities with the AHC outbreak. 30 virus strains were isolated, and two of the genomes had the highest identity values (95.8%) with CA24v genomes. Four CA24v genotypes were identified by phylogenetic analysis for the VP1 and 3C regions. CA24v which caused the outbreak belonged to genotype IV. Furthermore, full nucleotide sequences for four representative isolates in 2010 and 2007 were determined and compared. 20 aa mutations, two nt insertions and one nt deletion were observed in the open reading frame, with 5'- and 3'- UTR respectively between them.</p> <p>Conclusions</p> <p>CA24v was determined to be the pathogen causing the outbreak and belongs to genotype IV. VP1 is more informative than 3C<sup>Pro </sup>for describing molecular epidemiology and we hypothesize that accumulative mutations may have promoted the outbreak.</p

    Morphology, molecular genetics, and acoustics reveal two new species of the genus Leptobrachella from northwestern Guizhou Province, China (Anura, Megophryidae)

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    Two new species of the genus Leptobrachella Smith, 1925, L. bijie J. Wang, Y.L. Li, Y. Li, H.H. Chen &amp;amp; Y.Y. Wang, sp. nov. and L. purpuraventra J. Wang, Y.L. Li, Y. Li, H.H. Chen &amp;amp; Y.Y. Wang, sp. nov., were described from northwestern Guizhou Province, China based on a combination of acoustic, molecular, and morphological data. The new discoveries bring the total number of this genus to 73, with 16 congeners recorded in China, and represent the second and third species of the genus reported from Guizhou Province
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