182 research outputs found

    Method and Device for Removal of Cryoprotectant from Cryopreserved Biological Cells and Tissues

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    Novel methods and devices for removing cryoprotectant from cryoprotectant-containing liquids, and from cells residing therein, are disclosed. In one aspect, the method comprises passing the cryoprotectant-containing liquid through at least one semipermeable hollow fiber membrane contained in a hollow module in a first direction, while passing a liquid which is substantially free of cryoprotectant through the hollow module in a second direction to remove cryoprotectant across a diffusion gradient. In another aspect, a device is described for removing cryoprotectant from a liquid, comprising a hollow module with at least one semipermeable hollow fiber membrane therein for accomplishing such counter-current diffusion removal of cryprotectant. A software program is also provided for predicting optimal flow rates through the device of the invention, thereby allowing optimal cryoprotectant removal regardless of the cryoprotectant used or the material from which the semipermeable hollow fiber membrane is fabricated

    Methods and Devices for Cryopreservation of Biological Cells and Tissues

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    Novel methods, compositions, and devices for achieving optimal cooling of living cells during cryopreservation are disclosed. In one aspect, the method comprises gradually cooling the cell to a first predetermined temperature, followed by rapidly cooling the cell to a second predetermined temperature. In another aspect, a device is described for achieving a desired cooling rate for a cell, comprising a first container for holding a cell, a second container for holding the first container, and optionally a frame for holding the first container in a spaced apart relationship with the second container. The method of the invention comprises placing cells into the first container, placing the first container in the second container and sealing the second container, and placing the second container in a suitable cooling device. In yet another aspect, novel cryoprotectant compositions are provided comprising conventional cryoprotectant plus one or more high molecular weight cryoprotectants

    Chip-scale demonstration of hybrid III-V/silicon photonic integration for an FBG interrogator

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    Silicon photonic integration is a means to produce an integrated on-chip fiber Bragg grating (FBG) interrogator. The possibility of integrating the light source, couplers, grating couplers, de-multiplexers, photodetectors (PDs), and other optical elements of the FBG interrogator into one chip may result in game-changing performance advances, considerable energy savings, and significant cost reductions. To the best of our knowledge, this paper is the first to present a hybrid silicon photonic chip based on III–V/silicon-on-insulator photonic integration for an FBG interrogator. The hybrid silicon photonic chip consists of a multiwavelength vertical-cavity surface-emitting laser array and input grating couplers, a multimode interference coupler, an arrayed waveguide grating, output grating couplers, and a PD array. The chip can serve as an FBG interrogator on a chip and offer unprecedented opportunities. With a footprint of 5mm x 3mm, the proposed hybrid silicon photonic chip achieves an interrogation wavelength resolution of approximately 1 pm and a wavelength accuracy of about ±10 pm. With the measured 1 pm wavelength resolution, the temperature measurement resolution of the proposed chip is approximately 0.1°C. The proposed hybrid silicon photonic chip possesses advantages in terms of cost, manufacturability, miniaturization, and performance. The chip supports applications that require extreme miniaturization down to the level of smart grains

    Super-compact universal quantum logic gates with inversedesigned elements

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    Integrated quantum photonic circuit is a promising platform for the realization of quantum information processing in the future. To achieve the largescale quantum photonic circuits, the applied quantum logic gates should be as small as possible for the high-density integration on chips. Here, we report the implementation of super-compact universal quantum logic gates on silicon chips by the method of inverse design. In particular, the fabricated controlled-NOT gate and Hadamard gate are both nearly a vacuum wavelength, being the smallest optical quantum gates reported up to now. We further design the quantum circuit by cascading these fundamental gates to perform arbitrary quantum processing, where the corresponding size is about several orders smaller than that of previous quantum photonic circuits. Our study paves the way for the realization of largescale quantum photonic chips with integrated sources, and can possess important applications in the field of quantum information processes

    DeteX: A highly accurate software for detecting SNV and InDel in single and paired NGS data in cancer research

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    Background: Genetic testing is becoming more and more accepted in the auxiliary diagnosis and treatment of tumors. Due to the different performance of the existing bioinformatics software and the different analysis results, the needs of clinical diagnosis and treatment cannot be met. To this end, we combined Bayesian classification model (BC) and fisher exact test (FET), and develop an efficient software DeteX to detect SNV and InDel mutations. It can detect the somatic mutations in tumor-normal paired samples as well as mutations in a single sample.Methods: Combination of Bayesian classification model (BC) and fisher exact test (FET).Results: We detected SNVs and InDels in 11 TCGA glioma samples, 28 clinically targeted capture samples and 2 NCCL-EQA standard samples with DeteX, VarDict, Mutect, VarScan and GatkSNV. The results show that, among the three groups of samples, DeteX has higher sensitivity and precision whether it detects SNVs or InDels than other callers and the F1 value of DeteX is the highest. Especially in the detection of substitution and complex mutations, only DeteX can accurately detect these two kinds of mutations. In terms of single-sample mutation detection, DeteX is much more sensitive than the HaplotypeCaller program in Gatk. In addition, although DeteX has higher mutation detection capabilities, its running time is only .609 of VarDict, which is .704 and .343 longer than VarScan and MuTect, respectively.Conclusion: In this study, we developed DeteX to detect SNV and InDel mutations in single and paired samples. DeteX has high sensitivity and precision especially in the detection of substitution and complex mutations. In summary, DeteX from NGS data is a good SNV and InDel caller

    Low-mass dark matter search results from full exposure of PandaX-I experiment

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    We report the results of a weakly-interacting massive particle (WIMP) dark matter search using the full 80.1\;live-day exposure of the first stage of the PandaX experiment (PandaX-I) located in the China Jin-Ping Underground Laboratory. The PandaX-I detector has been optimized for detecting low-mass WIMPs, achieving a photon detection efficiency of 9.6\%. With a fiducial liquid xenon target mass of 54.0\,kg, no significant excess event were found above the expected background. A profile likelihood analysis confirms our earlier finding that the PandaX-I data disfavor all positive low-mass WIMP signals reported in the literature under standard assumptions. A stringent bound on the low mass WIMP is set at WIMP mass below 10\,GeV/c2^2, demonstrating that liquid xenon detectors can be competitive for low-mass WIMP searches.Comment: v3 as accepted by PRD. Minor update in the text in response to referee comments. Separating Fig. 11(a) and (b) into Fig. 11 and Fig. 12. Legend tweak in Fig. 9(b) and 9(c) as suggested by referee, as well as a missing legend for CRESST-II legend in Fig. 12 (now Fig. 13). Same version as submitted to PR
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