317 research outputs found

    Compact graphene mode-locked wavelength-tunable erbium-doped fiber lasers: from all anomalous dispersion towards all normal dispersion

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    Soliton operation and soliton wavelength tuning of erbium-doped fiber lasers mode locked with atomic layer graphene was experimentally investigated under various cavity dispersion conditions. It was shown that not only wide range soliton wavelength tuning but also soltion pulse width variation could be obtained in the fiber lasers. Our results show that the graphene mode locked erbium-doped fiber lasers provide a compact, user friendly and low cost wavelength tunable ultrahsort pulse source

    Preferential etching by flowing oxygen on the (100) surfaces of HPHT single-crystal diamond

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    Application of diamond is determined by its oxidation behaviour in some measure. Oxidation process of single-crystal diamond prepared under high pressure and high temperature has been studied by the thermal analysis, scanning electron microscope and Raman spectrometer. The result of a simultaneous thermal analysis indicates that single-crystal diamond is oxidized at ~ 818 °C at a heating rate of 5°C/min in the flowing oxygen. Based on the data of the thermal analysis at different heating rates, the activation energy is calculated by the Kissinger method. A weight loss rate increases with the rising heat treatment temperature from 600 to 800°C. After the oxidation at 800 °C, etch pits emerge on the {100} surfaces of single-crystal diamond, while the {111} surfaces are smooth. Shapes of the etch pits on the {100} surfaces are inverted pyramidal hollows, with edges direction parallel to the direction.Застосування алмазу в якійсь мірі визначається його поведінкою при окисленні. За допомогою термічного аналізу, скануючої електронної мікроскопії і спектроскопії комбінаційного розсіювання світла вивчено процес окислення монокристалічного алмазу, отриманого при високому тиску і високій температурі. Одночасний термічний аналіз показав, що монокристалічний алмаз окислюється при ~ 818 °С при швидкості нагріву 5 °С/хв в потоці кисню. На основі даних термічного аналізу при різних швидкостях нагрівання розраховано енергію активації за методом Кіссінджера. Швидкість втрати ваги зростає з підвищенням температури термообробки від 600 до 800 °C. Після окислення при температурі 800 °С ямки травлення з’являються на поверхні {100} монокристалічного алмазу, в той час як поверхні {111} гладкі. Форма ямок на поверхнях {100} – перевернуті пірамідальні западини з ребрами в напрямку паралельному .Применение алмаза в какой-то мере определяется его поведением при окислении. С помощью термического анализа, сканирующей электронной микроскопии и спектроскопии комбинационного рассеяния света изучен процесс окисления монокристаллического алмаза, полученного при высоком давлении и высокой температуре. Одновременный термический анализ показывает, что монокристаллический алмаз окисляется при ~ 818 °С при скорости нагрева 5 °С/мин в потоке кислорода. На основе данных термического анализа при различных скоростях нагрева рассчитана энергия активации по методу Киссинджера. Скорость потери веса возрастает с повышением температуры термообработки от 600 до 800 °C. После окисления при температуре 800 °С ямки травления появляются на поверхности {100} монокристаллического алмаза, в то время как поверхности {111} гладкие. Форма ямок на поверхностях {100} – перевернутые пирамидальные впадины с ребрами в направлении параллельном

    Diversity and distribution of Calonectria species from plantation and forest soils in Fujian province, China

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    To meet the growing demand for wood and pulp products, Eucalyptus plantations have expanded rapidly during the past two decades, becoming an integral part of the southern China landscape. Leaf blight caused by various Calonectria spp., is a serious threat to these plantations. In order to explore the diversity and distribution of Calonectria spp. in Fujian Province soils, samples were collected in Eucalyptus plantations and adjacent plantings of Cunninghamia lanceolata, Phyllostachys heterocycle and Pinus massoniana as well as in natural forests. Three hundred and fiftythree Calonectria isolates were recovered from soil samples and they were identified based on a comparison of multilocus DNA sequence data for the act (actin), cmdA (calmodulin), his3 (histone H3), rpb2 (the second largest subunit of RNA polymerase), tef1 (translation elongation factor 1-alpha) and tub2 (β-tubulin) gene regions, as well as morphological characteristics. Six known taxa including Calonectria aconidialis, Ca. hongkongensis, Ca. ilicicola, Ca. kyotensis, Ca. pacifica, Ca. pseudoreteaudii and one novel species described here as Ca. minensis sp. nov. were identified. Of these, Ca. aconidialis and Ca. kyotensis were the most prevalent species, and found in eight and seven sites, and four and five forest types, respectively. Calonectria spp. were most abundant in soils from Eucalyptus stands, followed by P. heterocycle and natural forests. Relatively few species were found in the soils associated with Cunninghamia lanceolata and Pinus massoniana. The abundance of known Calonectria spp. suggests that these fungi have been relatively well sampled in Fujian. The results are also consistent with the fact that most Calonectria diseases are found on Angiosperm as opposed to Gymnosperm plantsThe National Key R&D Program of China (China-South Africa Forestry Joint Research Centre Project; the special fund for basic scientific research of State Key Laboratory of Tree Genetics and Breeding (SKLTGB) of China, the National Ten-thousand Talents Program and the Guangdong Top Young Talents Program in China.http://www.mdpi.com/journal/jofBiochemistryForestry and Agricultural Biotechnology Institute (FABI)GeneticsMicrobiology and Plant Patholog

    Experimental Study on Seismic Behavior of Cluster-Reinforced Precast Concrete Columns with Grouting-Anchor Connections

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    The prefabricated residential buildings have become one of the most dominating construction methods in the modern construction industry. The seismic behavior of prefabricated components is crucial in the limit state design of the precast structure. This paper investigates the seismic behavior of a new type precast concrete column that has clustered steel reinforcement with grouting connection. Quasi-static tests are carried out on three cast-in-situ columns and seven precast columns. Axial compression ratio, lap length and lap space are the main variables considered. The failure process, hysteresis curve, skeleton curve, stiffness degradation, displacement ductility and energy dissipation are elaborated. The experimental results show that the precast columns with cluster reinforcement have similar seismic behavior to the cast-in-situ columns. Reducing the axial pressure can improve the ductility and energy consumption performance of the cluster-reinforced columns and exert its ductility to improve its seismic performance. During the assembly, a moderate increase in lap length can improve the seismic behavior of precast columns, whereas the lap space has an insignificant effect on the seismic behavior which indicates that the lap space is not an important factor during construction. The research outcome can serve as a reference for further development and application of precast structures

    Factors associated with adoption of the electronic health record system among primary care physicians

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    Background: A territory-wide Internet-based electronic patient record allows better patient care in different sectors. The engagement of private physicians is one of the major facilitators for implementation, but there is limited information about the current adoption level of electronic medical record (eMR) among private primary care physicians. Objective: This survey measured the adoption level, enabling factors, and hindering factors of eMR, among private physicians in Hong Kong. It also evaluated the key functions and the popularity of electronic systems and vendors used by these private practitioners. Methods: A central registry consisting of 4324 private practitioners was set up. Invitations for self-administered surveys and the completed questionnaires were sent and returned via fax, email, postal mail, and on-site clinic visits. Current users and non-users of eMR system were compared according to their demographic and practice characteristics. Student’s t tests and chi-square tests were used for continuous and categorical variables, respectively. Results: A total of 524 completed surveys (response rate 524/4405 11.90%) were collected. The proportion of using eMR in private clinics was 79.6% (417/524). When compared with non-users, the eMR users were younger (users: 48.4 years SD 10.6 years vs non-users: 61.7 years SD 10.2 years, P<.001); more were female physicians (users: 80/417, 19.2% vs non-users: 14/107, 13.1%, P=.013); possessed less clinical experience (with more than20 years of practice: users: 261/417, 62.6% vs non-user: 93/107, 86.9%, P<.001); fewer worked under a Health Maintenance Organization (users: 347/417, 83.2% vs non-users: 97/107, 90.7%, P<.001) and more worked with practice partners (users: 126/417, 30.2% vs non-users: 4/107, 3.7%, P<.001). Efficiency (379/417, 90.9%) and reduction of medical errors (229/417, 54.9%) were the major enabling factors, while patient-unfriendliness (58/107, 54.2%) and limited consultation time (54/107, 50.5%) were the most commonly reported hindering factors. The key functions of computer software among eMR users consisted of electronic patient registration system (376/417, 90.2%), drug dispensing system (328/417, 78.7%) and electronic drug labels (296/417, 71.0%). SoftLink Clinic Solution was the most popular vendor (160/417, 38.4%). Conclusions: These findings identified several physician groups who should be targeted for more assistance on eMR installation and its adoption. Future studies should address the barriers of using Internet-based eMR to enhance its adoption

    Reconsideration of species boundaries and proposed DNA barcodes for Calonectria

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    Calonectria represents a genus of phytopathogenic ascomycetous fungi with a worldwide distribution. In recent years, there has been an increase in the number of taxonomic studies on these fungi. Currently, there are 169 described species of Calonectria based on comparisons of DNA sequence data, combined with morphological characteristics. However, for some of these species, the sequence data utilised at the time of their description were relatively limited. This has justified an urgent need to reconsider the species boundaries for Calonectria based on robust genus-wide phylogenetic analyses. In this study, we utilised 240 available isolates including the ex-types of 128 Calonectria species, and re-sequenced eight gene regions (act, cmdA, his3, ITS, LSU, rpb2, tef1 and tub2) for them. Sequences for 44 Calonectria species, for which cultures could not be obtained, were downloaded from GenBank. DNA sequence data of all the 169 Calonectria species were then used to determine their phylogenetic relationships. As a consequence, 51 species were reduced to synonymy, two new species were identified, and the name Ca. lauri was validated. This resulted in the acceptance of 120 clearly defined Calonectria spp. The overall data revealed that the genus includes 11 species complexes, distributed across the Prolate and Sphaero-Naviculate Groups known to divide Calonectria. The results also made it possible to develop a robust set of DNA barcodes for Calonectria spp. To accomplish this goal, we evaluated the outcomes of each of the eight candidate DNA barcodes for the genus, as well as for each of the 11 species complexes. No single gene region provided a clear identity for all Calonectria species. Sequences of the tef1 and tub2 genes were the most reliable markers; those for the cmdA, his3, rpb2 and act gene regions also provided a relatively effective resolution for Calonectria spp., while the ITS and LSU failed to produce useful barcodes for species discrimination. At the species complex level, results showed that the most informative barcodes were inconsistent, but that a combination of six candidate barcodes (tef1, tub2, cmdA, his3, rpb2 and act) provided stable and reliable resolution for all 11 species complexes. A six-gene combined phylogeny resolved all 120 Calonectria species, and revealed that tef1, tub2, cmdA, his3, rpb2 and act gene regions are effective DNA barcodes for Calonectria.http://www.studiesinmycology.orgam2021BiochemistryForestry and Agricultural Biotechnology Institute (FABI)GeneticsMicrobiology and Plant Patholog

    Major vault protein suppresses obesity and atherosclerosis through inhibiting IKK-NF-kappa B signaling mediated inflammation

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    Macrophage-orchestrated, low-grade chronic inflammation plays a pivotal role in obesity and atherogenesis. However, the underlying regulatory mechanisms remain incompletely understood. Here, we identify major vault protein (MVP), the main component of unique cellular ribonucleoprotein particles, as a suppressor for NF-κB signaling in macrophages. Both global and myeloid-specific MVP gene knockout aggravates high-fat diet induced obesity, insulin resistance, hepatic steatosis and atherosclerosis in mice. The exacerbated metabolic disorders caused by MVP deficiency are accompanied with increased macrophage infiltration and heightened inflammatory responses in the microenvironments. In vitro studies reveal that MVP interacts with TRAF6 preventing its recruitment to IRAK1 and subsequent oligomerization and ubiquitination. Overexpression of MVP and its α-helical domain inhibits the activity of TRAF6 and suppresses macrophage inflammation. Our results demonstrate that macrophage MVP constitutes a key constraint of NF-κB signaling thereby suppressing metabolic diseases

    Reproducibility in the absence of selective reporting : An illustration from large-scale brain asymmetry research

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    Altres ajuts: Max Planck Society (Germany).The problem of poor reproducibility of scientific findings has received much attention over recent years, in a variety of fields including psychology and neuroscience. The problem has been partly attributed to publication bias and unwanted practices such as p-hacking. Low statistical power in individual studies is also understood to be an important factor. In a recent multisite collaborative study, we mapped brain anatomical left-right asymmetries for regional measures of surface area and cortical thickness, in 99 MRI datasets from around the world, for a total of over 17,000 participants. In the present study, we revisited these hemispheric effects from the perspective of reproducibility. Within each dataset, we considered that an effect had been reproduced when it matched the meta-analytic effect from the 98 other datasets, in terms of effect direction and significance threshold. In this sense, the results within each dataset were viewed as coming from separate studies in an "ideal publishing environment," that is, free from selective reporting and p hacking. We found an average reproducibility rate of 63.2% (SD = 22.9%, min = 22.2%, max = 97.0%). As expected, reproducibility was higher for larger effects and in larger datasets. Reproducibility was not obviously related to the age of participants, scanner field strength, FreeSurfer software version, cortical regional measurement reliability, or regional size. These findings constitute an empirical illustration of reproducibility in the absence of publication bias or p hacking, when assessing realistic biological effects in heterogeneous neuroscience data, and given typically-used sample sizes
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