116 research outputs found
Norovirus GII.17: The Emergence and Global Prevalence of a Novel Variant
A rare norovirus (NoV) genotype GII.17 has recently emerged and rapidly became predominant in most East Asian countries in the winters of 2014â2015. In this study, we report the diversity of NoV GII.17Â in detail; a total of 646 GII.17 sequences obtained during 1978â2015 were analyzed and subjected to meta-analysis. At least five major recombinant GII.17 clusters were identified. Each recombinant variant group appeared to have emerged following the time order: GII.P4-GII.17 (1978â1990), GII.P16-GII.17 (2001â2004), GII.P13-GII.17 (2004â2010), GII.Pe-GII.17 (2012â2015) and GII.P3-GII.17 (2011â2015). The newly emerged GII.P3-GII.17 variant, which exhibited significant sequence and structure variations, is evolving toward a unique lineage. Our results indicate that circulation of GII.17 appears to change every 3â5Â years due to replacement by a newly emerged variant and that the evolution of GII.17 is sequentially promoted by inter-genotype recombination, which contributes to the exchange between non-GII.17 and GII.17 RdRp genes and drives the evolution of GII.17 capsid genes
What They Gain Depends on What They Do: An Exploratory Empirical Research on Effective Use of Mobile Healthcare Applications
Mobile healthcare application receives widespread attention, although it has advanced technology and user-friendly design, when users donât use it effectively, it seems worthless. Research mainly focus on technology improvement. But how to improve user behavior to match the technology is another essential factor for facilitating effective use from managerial perspective. We introduced the task technology fit theory to explain the mechanism when user using the applications. We added perceived e-health literacy as moderator variable, considering the user characteristic and medical environment. The data was collected from student samples of two schools (medical and non-medical related universities), totally 178 valid samples. Our research indicates adaptation and learning behavior have significantly positive impact on the efficiency use and effectiveness use. The perceived e-health literacy only has significant moderator effect on learning behavior. Our study provides practical implications for both software providers and users to achieve effective use of mobile healthcare applications
In Search of Infall Motion in Molecular Clumps. IV. Mapping of the Global Infall Sources
We have used the IRAM 30-m telescope to map some targets with HCO (1-0)
and HCO (1-0) lines in order to search for gas infall evidence in
the clumps. In this paper, we report the mapping results for 13 targets. All of
these targets show HCO emissions, while HCO emissions are
observed in ten of them. The HCO integrated intensity maps of ten targets
show clear clumpy structures, and nine targets show clumpy structures in the
HCO maps. Using the RADEX radiative transfer code, we estimate the
column density of HCO, and determine the abundance ratio
[HCO]/[H] to be approximately 10 to 10. Based on
the asymmetry of the HCO line profiles, we identify 11 targets show blue
profiles, while six clumps have global infall evidence. We use the RATRAN and
two-layer models to fit the HCO line profiles of these infall sources, and
analyze their spatial distribution of the infall velocity. The average infall
velocities estimated by these two models are 0.24 -- 1.85 km s and 0.28
-- 1.45 km s, respectively. The mass infall rate ranges from
approximately 10 to 10 M yr, which suggests that
intermediate- or high-mass stars may be forming in the target regions
XAF1 expression and regulatory effects of somatostatin on XAF1 in prostate cancer cells
<p>Abstract</p> <p>Background</p> <p>Somatostatin prevents cell proliferation by inducing apoptosis. Downregulation of the <it>XAF1 </it>transcript may occur during the development of prostate cancer. It is interesting to evaluate the potential regulatory effects of somatostatin on <it>XAF1 </it>expression during the development of prostate cancer cells.</p> <p>Methods</p> <p><it>XAF1 </it>mRNA and protein expression in human prostate epithelial cells RWPE-1, androgen dependent prostate cancer LNCaP, and androgen independent DU145 and PC3 cells were evaluated using RT-PCR and Western blot. The regulation of <it>XAF1 </it>mRNA and protein expression by somatostatin and its analogue Octreotide was evaluated.</p> <p>Results</p> <p>Substantial levels of <it>XAF1 </it>mRNA and proteins were detected in RWPE-1 cells, whereas prostate cancer cells LNCaP, DU145 and PC3 exhibited lower <it>XAF1 </it>expression. Somatostatin and Octreotide up-regulated <it>XAF1 </it>mRNA and protein expression in all prostate cancer cell lines.</p> <p>Conclusions</p> <p><it>XAF1 </it>down-regulation may contribute to the prostate cancer development. The enhanced <it>XAF1 </it>expression by somatostatin indicates a promising strategy for prostate cancer therapy.</p
In search for infalling clumps in molecular clouds -- A catalogue of CO blue-profiles
We have started a systematic survey of molecular clumps with infall motions
to study the very early phase of star formation. Our first step is to utilize
the data products by MWISP to make an unbiased survey for blue asymmetric line
profiles of CO isotopical molecules. Within a total area of 2400 square
degrees nearby the Galactic plane, we have found 3533 candidates showing
blue-profiles, in which 3329 are selected from the CO&CO pair and
204 are from the CO&CO pair. Exploration of the parametric spaces
suggests our samples are in the cold phase with relatively high column
densities ready for star formation. Analysis of the spatial distribution of our
samples suggests that they exist virtually in all major components of the
Galaxy. The vertical distribution suggest that the sources are located mainly
in the thick disk of 85 parsec, but still a small part are located far
beyond Galactic midplane. Our follow-up observation indicates that these
candidates are a good sample to start a search for infall motions, and to study
the condition of very early phase of star formation
Research on Control Strategy of High-Speed Grid-Connected FESS (Flywheel Energy Storage System) Based on Dual-PWM Converter
FESS (flywheel energy storage system) motor is used in important load fields for instance rail transit; meanwhile the power flow is formed through the connection between FESS (flywheel energy storage system) and power grid system, which can critically improve the power flow fluctuation caused by new energy grid integration regarding wind and photovoltaic generation concerning that the motor speed in FESS is related to its energy storage capacity. Aiming at the limitation of current low motor speed in the FESS, this article puts forward a high-speed grid-connected FESS, and designs a model via the proposed dual-PWM two-stage control form, which is named as double closed-loop control. In this article, the FESS, as well as the power grid system, is analyzed and simulated in three stages: charging, pre-grid connection and grid connection. In this way, the flywheel motor speed and DC bus voltage signal are sampled to design the flywheel motor side with the proposed method. Then the grid-connected double closed-loop control method is designed for the sampling observation points, which realizes the efficient design on the control strategy of proposed high-speed grid-connected FESS and the verification of voltage and current parameters. The simulation experiments show that the operation process of the grid-connected FESS motor obtains its rapid speed response characteristic, which can meet the proposed design requirements during the charging and discharging process
Case Study of Mesoscale Precipitation Areas within the Comma Head of an Extratropical Cyclone
On 12–13 February 2016, a record-breaking rain–snow event during the passage of an extratropical cyclone occurred in Shandong Province, China, in which the 24 h precipitation totals at 48 of 123 national meteorological stations in Shandong Province broke their historical records for the month of February, and a further 25 stations recorded their second-largest February totals. This paper investigates the evolution of the mesoscale precipitation areas and the mechanisms responsible for the formation, organization, and maintenance of the mesoscale precipitation areas, using FY-2G satellite data, Doppler radar observations, and a Weather Research and Forecasting (WRF) model numerical simulation at 4 km grid spacing. The main results show that the comma head cloud of the cyclone developed from four echo strips. Intense precipitation was related to the mesoscale elongated precipitation areas (EPAs) of reflectivity >30 dBZ within the stratiform clouds. The formation and development of the EPAs coincided with the activities of a low-level shear line and an associated increase in frontogenesis. The simulated EPAs occurred in an environment of conditional instability (CI), inertial instability (II), and conditional symmetric instability (CSI). In the initial stage of the elongated rainfall areas (ERAs), rainfall was initiated by the frontal forcing in the presence of elevated CI, and II was generated by upright convection. During the development stage of the ERAs, the CI was absent, and condensational heating was enhanced. II occurred in the absence of upright convection, and it seems likely that the presence of II is a diabatic signature of the precipitation itself. Upper-level II intensified the convective systems by enhancing outflow aloft, and II caused the ERAs to organize. Thus, II played an important role in the organization and maintenance of the ERAs. The frontogenesis provided the dynamic condition for the release of the instability. Enhanced CSI and II intensified slantwise convection, and combining with enhanced frontogenesis, intensified the ERAs. The echo, ascent, and frontogenesis in snowfall areas were weaker than those in rainfall areas
Case Study of Mesoscale Precipitation Areas within the Comma Head of an Extratropical Cyclone
On 12â13 February 2016, a record-breaking rainâsnow event during the passage of an extratropical cyclone occurred in Shandong Province, China, in which the 24 h precipitation totals at 48 of 123 national meteorological stations in Shandong Province broke their historical records for the month of February, and a further 25 stations recorded their second-largest February totals. This paper investigates the evolution of the mesoscale precipitation areas and the mechanisms responsible for the formation, organization, and maintenance of the mesoscale precipitation areas, using FY-2G satellite data, Doppler radar observations, and a Weather Research and Forecasting (WRF) model numerical simulation at 4 km grid spacing. The main results show that the comma head cloud of the cyclone developed from four echo strips. Intense precipitation was related to the mesoscale elongated precipitation areas (EPAs) of reflectivity >30 dBZ within the stratiform clouds. The formation and development of the EPAs coincided with the activities of a low-level shear line and an associated increase in frontogenesis. The simulated EPAs occurred in an environment of conditional instability (CI), inertial instability (II), and conditional symmetric instability (CSI). In the initial stage of the elongated rainfall areas (ERAs), rainfall was initiated by the frontal forcing in the presence of elevated CI, and II was generated by upright convection. During the development stage of the ERAs, the CI was absent, and condensational heating was enhanced. II occurred in the absence of upright convection, and it seems likely that the presence of II is a diabatic signature of the precipitation itself. Upper-level II intensified the convective systems by enhancing outflow aloft, and II caused the ERAs to organize. Thus, II played an important role in the organization and maintenance of the ERAs. The frontogenesis provided the dynamic condition for the release of the instability. Enhanced CSI and II intensified slantwise convection, and combining with enhanced frontogenesis, intensified the ERAs. The echo, ascent, and frontogenesis in snowfall areas were weaker than those in rainfall areas
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