7,562 research outputs found
Structural variations of Si 1-xC x and their light absorption controllability
The emergence of third-generation photovoltaics based on Si relies on tunable bandgap materials with embedded nanocrystalline Si. One of the most promising approaches is based on the mixed-phase Si1 -aEuro parts per thousand x C (x) . We have investigated the light absorption controllability of nanocrystalline Si-embedded Si1 -aEuro parts per thousand x C (x) produced by thermal annealing of the Si-rich Si1 -aEuro parts per thousand x C (x) and composition-modulated superlattice structure. In addition, stoichiometric SiC was also investigated to comparatively analyze the characteristic differences. As a result, it was found that stoichiometric changes of the matrix material and incorporation of oxygen play key roles in light absorption controllability. Based on the results of this work and literature, a design strategy of nanocrystalline Si-embedded absorber materials for third-generation photovoltaics is discussed.open3
Actin Cytoskeleton and Golgi Involvement in Barley stripe mosaic virus Movement and Cell Wall Localization of Triple Gene Block Proteins.
Barley stripe mosaic virus (BSMV) induces massive actin filament thickening at the infection front of infected Nicotiana benthamiana leaves. To determine the mechanisms leading to actin remodeling, fluorescent protein fusions of the BSMV triple gene block (TGB) proteins were coexpressed in cells with the actin marker DsRed: Talin. TGB ectopic expression experiments revealed that TGB3 is a major elicitor of filament thickening, that TGB2 resulted in formation of intermediate DsRed:Talin filaments, and that TGB1 alone had no obvious effects on actin filament structure. Latrunculin B (LatB) treatments retarded BSMV cell-to-cell movement, disrupted actin filament organization, and dramatically decreased the proportion of paired TGB3 foci appearing at the cell wall (CW). BSMV infection of transgenic plants tagged with GFP-KDEL exhibited membrane proliferation and vesicle formation that were especially evident around the nucleus. Similar membrane proliferation occurred in plants expressing TGB2 and/or TGB3, and DsRed: Talin fluorescence in these plants colocalized with the ER vesicles. TGB3 also associated with the Golgi apparatus and overlapped with cortical vesicles appearing at the cell periphery. Brefeldin A treatments disrupted Golgi and also altered vesicles at the CW, but failed to interfere with TGB CW localization. Our results indicate that actin cytoskeleton interactions are important in BSMV cell-to-cell movement and for CW localization of TGB3
Efficient Bayesian hierarchical functional data analysis with basis function approximations using Gaussian-Wishart processes
Functional data are defined as realizations of random functions (mostly
smooth functions) varying over a continuum, which are usually collected with
measurement errors on discretized grids. In order to accurately smooth noisy
functional observations and deal with the issue of high-dimensional observation
grids, we propose a novel Bayesian method based on the Bayesian hierarchical
model with a Gaussian-Wishart process prior and basis function representations.
We first derive an induced model for the basis-function coefficients of the
functional data, and then use this model to conduct posterior inference through
Markov chain Monte Carlo. Compared to the standard Bayesian inference that
suffers serious computational burden and unstableness for analyzing
high-dimensional functional data, our method greatly improves the computational
scalability and stability, while inheriting the advantage of simultaneously
smoothing raw observations and estimating the mean-covariance functions in a
nonparametric way. In addition, our method can naturally handle functional data
observed on random or uncommon grids. Simulation and real studies demonstrate
that our method produces similar results as the standard Bayesian inference
with low-dimensional common grids, while efficiently smoothing and estimating
functional data with random and high-dimensional observation grids where the
standard Bayesian inference fails. In conclusion, our method can efficiently
smooth and estimate high-dimensional functional data, providing one way to
resolve the curse of dimensionality for Bayesian functional data analysis with
Gaussian-Wishart processes.Comment: Under revie
Long carrier lifetimes in GaN epitaxial layers grown using TiN porous network templates
Improved structural quality and radiative efficiency were observed in GaNthin filmsgrown by metalorganic chemical vapor deposition on TiN porous network templates formed by in situthermal annealing of Ti in ammonia. The room-temperature decay times obtained from biexponential fits to time-resolved photoluminescence data are longer than ever reported for GaN. The carrier lifetime of 1.86 ns measured for a TiN network sample is slightly longer than that for a 200 μm thick high-quality freestanding GaN. The linewidth of the asymmetric x-ray diffraction(XRD)(101¯2) peak decreases considerably with the use of TiN layer and with increasing in situannealing time, indicating the reduction in threading dislocation density. However, no direct correlation is yet found between the decay times and the XRD linewidths, suggesting that point defect and impurity related nonradiative centers are the main parameters affecting the lifetime
Universal conductance fluctuations in three dimensional metallic single crystals of Si
In this paper we report the measurement of conductance fluctuations in single
crystals of Si made metallic by heavy doping (n \approx 2-2.5n_c, n_c being
critical composition at Metal-Insulator transition). Since all dimensions (L)
of the samples are much larger than the electron phase coherent length L_\phi
(L/L_\phi \sim 10^3), our system is truly three dimensional. Temperature and
magnetic field dependence of noise strongly indicate the universal conductance
fluctuations (UCF) as predominant source of the observed magnitude of noise.
Conductance fluctuations within a single phase coherent region of L_\phi^3 was
found to be saturated at \approx (e^2/h)^2. An accurate
knowledge of the level of disorder, enables us to calculate the change in
conductance \delta G_1 due to movement of a single scatterer as \delta G_1 \sim
e^2/h, which is \sim 2 orders of magnitude higher than its theoretically
expected value in 3D systems.Comment: Text revised version. 4 eps figs unchange
Importance of Itinerancy and Quantum Fluctuations for the Magnetism in Iron Pnictides
By applying density functional theory, we find strong evidence for an
itinerant nature of magnetism in two families of iron pnictides. Furthermore,
by employing dynamical mean field theory with continuous time quantum Monte
Carlo as an impurity solver, we observe that the antiferromagnetic metal with
small magnetic moment naturally arises out of coupling between unfrustrated and
frustrated bands. Our results point to a possible scenario for magnetism in
iron pnictides where magnetism originates from a strong instability at the
momentum vector (, , ) while it is reduced by quantum
fluctuations due to the coupling between weakly and strongly frustrated bands.Comment: 4 pages, 4 figure
Information flow between stock indices
Using transfer entropy, we observed the strength and direction of information
flow between stock indices. We uncovered that the biggest source of information
flow is America. In contrast, the Asia/Pacific region the biggest is receives
the most information. According to the minimum spanning tree, the GSPC is
located at the focal point of the information source for world stock markets
Integrative Medicine for Postoperative Patients: A Survey of Korean Medicine Doctors
The purpose of this survey was to document the experience of Korean Medicine doctors (KMD) who provided postoperative care to patients through integrative medicine and to understand their opinions about integrative medicine utilization. Three researchers (two with a KMD license) of the Korea Institute of Oriental Medicine conducted the survey. The questionnaire was distributed via e-mail to the 17,041 members of the Association of Korean Medicine in 2015. In total, 487 KMD answered the questionnaires. The majority of respondents worked in a Korean Medicine (KM) clinic, KM hospital, or long-term care hospitals (94.7%). The respondents mostly treated patients after musculoskeletal (26.7%), spinal (23.7%), or neuropathic surgery (22.2%). Patients predominantly experienced pain (23.0%), fatigue and tiredness (17.4%), delayed scar recovery (13.7%), and paralysis (13.0%). We analyzed subgroups in accordance with institution of employment, specialization, and clinical experience. Most KMD wanted to utilize integrative medicine for postoperative care of patients (92.6%). Moreover, a relatively active collaboration was noted in long-term care hospitals (mean rate: 60.73% [95% CI: 42.25 to 79.20]). Further studies and clinical trials are needed to determine whether integrative medicine is essential for providing postoperative care to Korean patients
The Complete Chloroplast Genomes of Six Ipomoea Species and Indel Marker Development for the Discrimination of Authentic Pharbitidis Semen (Seeds of I. nil or I. purpurea)
Ipomoea L. is the largest genus within the Convolvulaceae and contains 600–700 species. Ipomoea species (morning glories) are economically valuable as horticultural species and scientifically valuable as ecological model plants to investigate mating systems, molecular evolution, and both plant–herbivore and plant–parasite interactions. Furthermore, the dried seeds of I. nil or I. purpurea are used in Korean traditional herbal medicines. In this study, chloroplast (cp) genomes were sequenced from six Ipomoea species, namely, I. nil and I. purpurea and, for the first time, I. triloba, I. lacunosa, I. hederacea, and I. hederacea var. integriuscula. The cp genomes were 161,354–161,750 bp in length and exhibited conserved quadripartite structures. In total, 112 genes were identified, including 78 protein-coding regions, 30 transfer RNA genes, and 4 ribosomal RNA genes. The gene order, content, and orientation of the six Ipomoea cp genomes were highly conserved and were consistent with the general structure of angiosperm cp genomes. Comparison of the six Ipomoea cp genomes revealed locally divergent regions, mainly within intergenic spacer regions (petN-psbM, trnI-CAU-ycf2, ndhH-ndhF, psbC-trnS, and ccsA-ndhD). In addition, the protein-coding genes accD, cemA, and ycf2 exhibited high sequence variability and were under positive selection (Ka/Ks > 1), indicating adaptive evolution to the environment within the Ipomoea genus. Phylogenetic analysis of the six Ipomoea species revealed that these species clustered according to the APG IV system. In particular, I. nil and I. hederacea had monophyletic positions, with I. purpurea as a sister. I. triloba and I. lacunosa in the section Batatas and I. hederacea and I. hederacea var. integriuscula in the section Quamoclit were supported in this study with strong bootstrap values and posterior probabilities. We uncovered high-resolution phylogenetic relationships between Ipomoeeae. Finally, indel markers (IPOTY and IPOYCF) were developed for the discrimination of the important herbal medicine species I. nil and I. purpurea. The cp genomes and analyses in this study provide useful information for taxonomic, phylogenetic, and evolutionary analysis of the Ipomoea genome, and the indel markers will be useful for authentication of herbal medicines
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