255 research outputs found

    The preprophase band-associated kinesin-14 OsKCH2 is a processive minus-end-directed microtubule motor.

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    In animals and fungi, cytoplasmic dynein is a processive minus-end-directed motor that plays dominant roles in various intracellular processes. In contrast, land plants lack cytoplasmic dynein but contain many minus-end-directed kinesin-14s. No plant kinesin-14 is known to produce processive motility as a homodimer. OsKCH2 is a plant-specific kinesin-14 with an N-terminal actin-binding domain and a central motor domain flanked by two predicted coiled-coils (CC1 and CC2). Here, we show that OsKCH2 specifically decorates preprophase band microtubules in vivo and transports actin filaments along microtubules in vitro. Importantly, OsKCH2 exhibits processive minus-end-directed motility on single microtubules as individual homodimers. We find that CC1, but not CC2, forms the coiled-coil to enable OsKCH2 dimerization. Instead, our results reveal that removing CC2 renders OsKCH2 a nonprocessive motor. Collectively, these results show that land plants have evolved unconventional kinesin-14 homodimers with inherent minus-end-directed processivity that may function to compensate for the loss of cytoplasmic dynein

    Post-activation Performance Enhancement after a Bout of Accentuated Eccentric Loading in Collegiate Male Volleyball Players

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    The purpose of this study was to investigate the benefit of post-activation performance enhancement (PAPE) after accentuated eccentric loading (AEL) compared to traditional resistance loading (TR). Sixteen male volleyball athletes were divided in AEL and TR group. AEL group performed 3 sets of 4 repetitions (eccentric: 105% of concentric 1RM, concentric: 80% of concentric 1RM) of half squat, and TR group performed 3 sets of 5 repetitions (eccentric & concentric: 85% of 1RM). Countermovement jump (CMJ), spike jump (SPJ), isometric mid-thigh pull (IMTP), and muscle soreness test were administered before (Pre) exercise, and 10 min (10-min), 24 h (24-h), and 48 h (48-h) after exercise. A two-way repeated measures analysis of variance was used to analyze the data. Peak force and rate of development (RFD) of IMTP in AEL group were significantly greater (p 0.05) groups x time. AEL seemed capable to maintain force production in IMTP, but not in CMJ and SPJ. It is recommended the use of accentuated eccentric loading protocols to overcome the fatigue

    Neural \'{E}tendue Expander for Ultra-Wide-Angle High-Fidelity Holographic Display

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    Holographic displays can generate light fields by dynamically modulating the wavefront of a coherent beam of light using a spatial light modulator, promising rich virtual and augmented reality applications. However, the limited spatial resolution of existing dynamic spatial light modulators imposes a tight bound on the diffraction angle. As a result, modern holographic displays possess low \'{e}tendue, which is the product of the display area and the maximum solid angle of diffracted light. The low \'{e}tendue forces a sacrifice of either the field-of-view (FOV) or the display size. In this work, we lift this limitation by presenting neural \'{e}tendue expanders. This new breed of optical elements, which is learned from a natural image dataset, enables higher diffraction angles for ultra-wide FOV while maintaining both a compact form factor and the fidelity of displayed contents to human viewers. With neural \'{e}tendue expanders, we experimentally achieve 64×\times \'{e}tendue expansion of natural images in full color, expanding the FOV by an order of magnitude horizontally and vertically, with high-fidelity reconstruction quality (measured in PSNR) over 29 dB on retinal-resolution images

    Hepatitis Delta Virus RNA Replication

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    Hepatitis delta virus (HDV) is a distant relative of plant viroids in the animal world. Similar to plant viroids, HDV replicates its circular RNA genome using a double rolling-circle mechanism. Nevertheless, the production of hepatitis delta antigen (HDAg), which is indispensible for HDV replication, is a unique feature distinct from plant viroids, which do not encode any protein. Here the HDV RNA replication cycle is reviewed, with emphasis on the function of HDAg in modulating RNA replication and the nature of the enzyme involved

    Fabrication and Characterization of CuInSe 2

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    The chalcopyrite CuInSe2 thin film synthesized via a low temperature solid state reaction from CuSe and InSe powders was investigated using X-ray diffractomy (XRD), scanning electron microscope (SEM), energy dispersive spectrometer (EDS), transmission electron microscopy (TEM), and UV-vis absorption spectroscopy. CuSe and InSe phases react and directly transform into CuInSe2 without the occurrence of any intermediate phase. The morphology of the newly formed CuInSe2 crystalline was close to that of the CuSe reactant particle based on the TEM results, which indicate that the solid state reaction kinetics may be dominated by the In3+ ions diffusion. The CuInSe2 thin film prepared from the solid state reaction did not use the selenide process; its band gap might reach 1.06 eV, which is competent and suitable to be used for a thin film solar cell light absorption layer

    Associations between Aerosol Types and Chlorophyll-a Concentration over Coastal Area in East Asia from Satellite Observations

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    This study improved significantly the relationship between aerosol optical depth (AOD) and sea surface chlorophyll-a concentration (Chl-a), after considering the effects of sea surface temperature (SST), ocean surface current (OSC) and type of aerosols. The decadal satellite-retrieved Orbview-2/SeaWiFS Chl-a and Terra/MODIS AOD550nm data (from March 2000 to December 2010) were used to investigate the impact of atmospheric aerosols on the Chl-a concentration in the coastal water around the region of East Asia (equator to 75°N and from 100°E to 180°E). Two sets of sequential areas (A1 to A10 and B1 to B9) were selected for examining and excluding the influence of SST and OSC. After taking the potential location of aerosol deposition from OSC into account, an obvious correlation between AOD550nm and Chl-a concentration was demonstrated around the site of study area A. For aerosol partition, the Normalized Gradient Aerosol Index (NGAI) was applied to MODIS AOD products for aerosol type identification and mixed status determination. The results indicated that the type of mineral dust (DS) significantly increases the Chl-a while the biomass burning (BB) aerosols may restrain the Chl-a. This seems to be a non-impact of anthropogenic pollutant (AP) on Chl-a within the surface layer. The other area, B (B1 to B9), next to the region of area A, also shows similar results with high consistency; thus, the significant impact of DS aerosols on Chl-a production is suggested over the coastal region of East Asia

    Evolution of carbapenem resistance in Acinetobacter baumannii: An 18-year longitudinal study from a medical center in northern Taiwan

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    BackgroundCarbapenem-resistant Acinetobacter baumannii has emerged as an important cause of nosocomial infections with high morbidity and mortality. The carbapenemases, especially class D carbapenem-hydrolyzing oxacillinases (CHDLs), play an important role, but the relationship between their prevalence trend and carbapenem resistance remains unclear.Materials and methodsBetween 1995 and 2012, we collected 667 isolates of A. baumannii from a single medical center in northern Taiwan. Pulsed-field gel electrophoresis (PFGE) was used to determine clonality. Antimicrobial susceptibility was determined. Carbapenemase genes and associated genetic structures were detected by polymerase chain reaction.ResultsIsolates were heterogeneous on PFGE. Susceptibility to carbapenem decreased steadily over the study period from 88.1% (2001–2003) to <25% (2010–2012), whereas the isolates remained susceptible to colistin (nearly 100%) and partially susceptible to tigecycline (80%). Starting in 2001, isolates carrying the ISAba1-blaOXA-51-like allele were consistently identified. Isolates containing the transposons Tn2006 or Tn2008 first appeared in 2007 with increasing carriage rates from 17.5% (2007–2009) to 50.0% (2010–2012). The IS1008-ΔISAba3-blaOXA-58-like, blaOXA-72 and metallo-β-lactamase genes were detected only sporadically. Isolates carrying CHDL genes were resistant to multiple drugs, including carbapenem, but remained susceptible to colistin (100.0%).ConclusionIncreased carbapenem resistance in A. baumannii may be caused by the increased prevalence of isolates containing the ISAba1-blaOXA-51-like allele and the transposons Tn2006 and Tn2008

    Direct evidence of ZnO morphology modification via the selective adsorption of ZnO-binding peptides

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    Biomolecule-mediated ZnO synthesis has great potential for the tailoring of ZnO morphology for specific application in biosensors, window materials for display and solar cells, dye-sensitized solar cells (DSSCs), biomedical materials, and photocatalysts due to its specificity and multi-functionality. In this contribution, the effect of a ZnO-binding peptide (ZnO-BP, G-12: GLHVMHKVAPPR) and its GGGC-tagged derivative (GT-16: GLHVMHKVAPPRGGGC) on the growth of ZnO crystals expressing morphologies dependent on the relative growth rates of (0001) and (10 (1) over bar0) planes of ZnO have been studied. The amount of peptide adsorbed was determined by a depletion method using oriented ZnO films grown by Atomic Layer Deposition (ALD), while the adsorption behavior of G-12 and GT-16 was investigated using XPS and a computational approach. Direct evidence was obtained to show that (i) both the ZnO-BP identified by phage display and its GGGC derivative (GT-16) are able to bind to ZnO and modify crystal growth in a molecule and concentration dependent fashion, (ii) plane selectivity for interaction with the (0001) versus the (10 (1) over bar0) crystal planes is greater for GT-16 than G-12; and (iii) specific peptide residues interact with the crystal surface albeit in the presence of charge compensating anions. To our knowledge, this is the first study to provide unambiguous and direct quantitative experimental evidence of the modification of ZnO morphology via (selective and nonselective) adsorption-growth inhibition mechanisms mediated by a ZnO-BP identified from phage display libraries

    Non-invasive and transdermal measurement of blood uric acid level in human by electroporation and reverse iontophoresis

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    The aim of this study was to find out the optimum combination of electroporation (EP) and reverse iontophoresis (RI) on noninvasive and transdermal determination of blood uric acid level in humans. EP is the use of high-voltage electric pulse to create nano-channels on the stratum corneum, temporarily and reversibly. RI is the use of small current to facilitate both charged and uncharged molecule transportation across the skin. It is believed that the combination of these two techniques has additional benefits on the molecules’ extraction across the human skin. In vitro studies using porcine skin and diffusion cell have indicated that the optimum mode for transdermal uric acid extraction is the combination of RI with symmetrical biphasic direct current (current density = 0.3 mA/cm2; phase duration = 180 s) and EP with 10 pulses per second (voltage = 100 V/cm2; pulse width = 1 ms). This optimum mode was applied to six human subjects. Uric acid was successfully extracted through the subjects’ skin into the collection solution. A good correlation (r2 = 0.88) between the subject’s blood uric acid level and uric acid concentrations in collection solutions was observed. The results suggest that it may be possible to noninvasively and transdermally determine blood uric acid levels
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