106 research outputs found

    Electricity Harvested from Ambient Heat across Silicon Surface

    Full text link
    We report that electricity can be generated from limitless thermal motion of ions by two dimensional (2D) surface of silicon wafer at room temperature. A typical silicon device, on which asymmetric electrodes with Au and Ag thin films were fabricated, can generate a typical open-circuit voltage up to 0.40 V in 5 M CuCl2 solution and an output current over 11 {\mu}A when a 25 k{\Omega} resistor was loaded into the circuit. Positive correlation between the output current and the temperature, as well as the concentration, was observed. The maximum output current and power density are 17 {\mu}A and 8.6 {\mu}W/cm2, respectively. The possibility of chemical reaction was excluded by four groups of control experiments. A possible dynamic drag mechanism was proposed to explain the experimental results. This finding further demonstrates that ambient heat in the environment can be harvested by 2D semiconductor surfaces or low dimensional materials and would contribute significantly to the research of renewable energy. However, this finding does not agree with the second law of thermal dynamatics. A lot of future work will be needed to study the mechanism behind this phenomenon

    Virtual k -Space Modulation Optical Microscopy

    Get PDF
    We report a novel superresolution microscopy approach for imaging fluorescence samples. The reported approach, termed virtual k-space modulation optical microscopy (VIKMOM), is able to improve the lateral resolution by a factor of 2, reduce the background level, improve the optical sectioning effect and correct for unknown optical aberrations. In the acquisition process of VIKMOM, we used a scanning confocal microscope setup with a 2D detector array to capture sample information at each scanned x-y position. In the recovery process of VIKMOM, we first modulated the captured data by virtual k-space coding and then employed a ptychography-inspired procedure to recover the sample information and correct for unknown optical aberrations. We demonstrated the performance of the reported approach by imaging fluorescent beads, fixed bovine pulmonary artery endothelial (BPAE) cells, and living human astrocytes (HA). As the VIKMOM approach is fully compatible with conventional confocal microscope setups, it may provide a turn-key solution for imaging biological samples with ∼100  nm lateral resolution, in two or three dimensions, with improved optical sectioning capabilities and aberration correcting.National Institutes of Health (U.S.) (9P41EB015871-26A1)National Institutes of Health (U.S.) (1R01HL121386-01A1

    Field performance of transgenic elite commercial hybrid rice expressing Bacillus thuringiensis δ-endotoxin

    Get PDF
    Here we describe development of transgenic elite rice lines expressing a Bt fusion gene derived from cryIA(b) and cryIA(c) under the control of rice actinI promoter. The lines used in the study were indica CMS restorer line of Minghui 63 and its derived hybrid rice Shanyou 63. The level of Bt fusion protein CryIA(b)/CryIA(c) detected in Minghui 63 (T51-1) plants was 20 ng/mg soluble protein. The Bt Shanyou 63 was field-tested in natural and repeated heavy manual infestation of two lepidopteran insects, leaffolder and yellow stem borer. The transgenic hybrid plants showed high protection against both insect pests without reduced yield

    Site-independently integrated transgenes in the elite restorer rice line Minghui 63 allow removal of a selectable marker from the gene of interest by self-segregation

    Get PDF
    In this study, we have demonstrated that two independent loci are involved in the integration of the insecticidal protein gene cryIAb/cryIAc and selectable marker gene hph in the recipient genome of the elite Chinese CMS restorer line Minghui 63. We have also documented the structural organization of these transgenes in each locus by restriction enzyme digestion and Southern blot analysis. The independent locus integration of different transgenes allowed us to remove the selectable marker gene hph from the gene of interest simply by self-segregation. Not having the selectable marker gene will enhance the commercial value of our transgenic line TT51-1, which showed a consistently high level of resistance against repeated infestations of yellow stem borers and natural outbreaks of leaf-folders, without a reduction in yield potential

    Cancer drug indication approvals in China and the United States: a comparison of approval times and clinical benefit, 2001–2020

    Get PDF
    BACKGROUND: Perceived delays in cancer drug approvals have been a major concern for policymakers in China. Policies have been implemented to accelerate the launch of new cancer drugs and indications. This study aimed to assess similarities and differences between China and the United States in the approvals, timing, and clinical benefit evidence of cancer drug indications between 2001 and 2020. METHODS: This study retrospectively identified all cancer drugs and indications approved in both China and the United States from January 1st, 2001 to December 31, 2020, and described differences in approval times as well as in submission and review times. Information on the availability of overall survival benefit evidence by December 31, 2020, was collected. Univariate and multiple logistic regression analyses were used to assess whether evidence of benefit and other factors affected the propensity and timing of approvals of cancer drug indications in China. FINDINGS: Between 2001 and 2020, 229 indications corresponding to 145 cancer drugs approved in the United States were identified. Of those, 80 indications (34.9%) were also approved in China by the end of 2020. Cancer drug indications were approved in China at a median of 1273.5 days after approval in the United States. The median submission and review time differences for cancer drug indications in China were 1198.0 days and 180.0 days respectively. Submission time differences accounted for most of the approval time differences (p < 0.001). Indications supported by overall survival benefit evidence had shorter median review time differences (145.0 days) than those without such evidence (235.0 days, p = 0.008). Indications with overall survival benefit evidence were 3.94 times more likely to be approved in China compared to those without such evidence (p = 0.001), controlling for approval year, cancer type, and the prevalence of cancer by site. INTERPRETATION: FDA-approved cancer drug indications demonstrating a survival benefit were more likely to receive approvals in China with shorter regulatory review times compared to indications without such evidence. Given that manufacturer submission times were the main driver of cancer drug approval times in China, factors influencing submission timing should be explored. FUNDING: No funding

    Distributed Power Allocation for Sink-Centric Clusters in Multiple Sink Wireless Sensor Networks

    Get PDF
    Due to the battery resource constraints, saving energy is a critical issue in wireless sensor networks, particularly in large sensor networks. One possible solution is to deploy multiple sink nodes simultaneously. Another possible solution is to employ an adaptive clustering hierarchy routing scheme. In this paper, we propose a multiple sink cluster wireless sensor networks scheme which combines the two solutions, and propose an efficient transmission power control scheme for a sink-centric cluster routing protocol in multiple sink wireless sensor networks, denoted as MSCWSNs-PC. It is a distributed, scalable, self-organizing, adaptive system, and the sensor nodes do not require knowledge of the global network and their location. All sinks effectively work out a representative view of a monitored region, after which power control is employed to optimize network topology. The simulations demonstrate the advantages of our new protocol
    corecore