398 research outputs found

    Compartmentalization of incompatible reagents within Pickering emulsion droplets for one-pot cascade reactions

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    It is a dream that future synthetic chemistry can mimic living systems to process multistep cascade reactions in a one-pot fashion. One of the key challenges is the mutual destruction of incompatible or opposing reagents, for example, acid and base, oxidants and reductants. A conceptually novel strategy is developed here to address this challenge. This strategy is based on a layered Pickering emulsion system, which is obtained through lamination of Pickering emulsions. In this working Pickering emulsion, the dispersed phase can separately compartmentalize the incompatible reagents to avoid their mutual destruction, while the continuous phase allows other reagent molecules to diffuse freely to access the compartmentalized reagents for chemical reactions. The compartmentalization effects and molecular transport ability of the Pickering emulsion were investigated. The deacetalization–reduction, deacetalization–Knoevenagel, deacetalization–Henry and diazotization–iodization cascade reactions demonstrate well the versatility and flexibility of our strategy in processing the one-pot cascade reactions involving mutually destructive reagents

    DEC2 modulates orexin expression and regulates sleep.

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    Adequate sleep is essential for physical and mental health. We previously identified a missense mutation in the human DEC2 gene (BHLHE41) leading to the familial natural short sleep behavioral trait. DEC2 is a transcription factor regulating the circadian clock in mammals, although its role in sleep regulation has been unclear. Here we report that prepro-orexin, also known as hypocretin (Hcrt), gene expression is increased in the mouse model expressing the mutant hDEC2 transgene (hDEC2-P384R). Prepro-orexin encodes a precursor protein of a neuropeptide producing orexin A and B (hcrt1 and hcrt2), which is enriched in the hypothalamus and regulates maintenance of arousal. In cell culture, DEC2 suppressed prepro-orexin promoter-luc (ore-luc) expression through cis-acting E-box elements. The mutant DEC2 has less repressor activity than WT-DEC2, resulting in increased orexin expression. DEC2-binding affinity for the prepro-orexin gene promoter is decreased by the P384R mutation, likely due to weakened interaction with other transcription factors. In vivo, the decreased immobility time of the mutant transgenic mice is attenuated by an orexin receptor antagonist. Our results suggested that DEC2 regulates sleep/wake duration, at least in part, by modulating the neuropeptide hormone orexin

    Controlling Capillary-Driven Fluid Transport in Paper-Based Microfluidic Devices Using a Movable Valve

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    This paper describes a novel, strategy for fabricating the movable valve on paper-based microfluidic devices to manipulate capillary-driven fluids. The movable valve fabrication is first realized using hollow rivets as the-holding center it, control the paper channel in different layer movement that Jesuits in the :channel's connection or disconnection. The relatively simple Valve fabrication procedure is robust, Versatile, and, compatible with microfluidic paper-based analytical devices (mu PADs) with differing levels of complexity. It is remarkable that the movable valve can be convenient and free to control fluid without the timing setting; advantages that make it user-friendly for untrained users to carry out the complex multistep operations. For the, performance of the Movable valve to be-verified, several different designs of mu PADs were tested and obtained with satisfactory results. In addition; in the proof-of-concept enzyme-linked immunosorbent assay experiments, we demonstrate the use of these valves in mu PADs for the successful analysis of samples of carcino-embryonic antigen, showing good sensitivity and reproducibility. We hope this technique will open new avenues for the fabrication of paper-based valves in an easily adoptable and widely available way on mu PADs and provide potential point-of-Care applications in the future.This paper describes a novel, strategy for fabricating the movable valve on paper-based microfluidic devices to manipulate capillary-driven fluids. The movable valve fabrication is first realized using hollow rivets as the-holding center it, control the paper channel in different layer movement that Jesuits in the :channel's connection or disconnection. The relatively simple Valve fabrication procedure is robust, Versatile, and, compatible with microfluidic paper-based analytical devices (mu PADs) with differing levels of complexity. It is remarkable that the movable valve can be convenient and free to control fluid without the timing setting; advantages that make it user-friendly for untrained users to carry out the complex multistep operations. For the, performance of the Movable valve to be-verified, several different designs of mu PADs were tested and obtained with satisfactory results. In addition; in the proof-of-concept enzyme-linked immunosorbent assay experiments, we demonstrate the use of these valves in mu PADs for the successful analysis of samples of carcino-embryonic antigen, showing good sensitivity and reproducibility. We hope this technique will open new avenues for the fabrication of paper-based valves in an easily adoptable and widely available way on mu PADs and provide potential point-of-Care applications in the future

    A Novel Deployment Scheme Based on Three-Dimensional Coverage Model for Wireless Sensor Networks

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    Coverage pattern and deployment strategy are directly related to the optimum allocation of limited resources for wireless sensor networks, such as energy of nodes, communication bandwidth, and computing power, and quality improvement is largely determined by these for wireless sensor networks. A three-dimensional coverage pattern and deployment scheme are proposed in this paper. Firstly, by analyzing the regular polyhedron models in three-dimensional scene, a coverage pattern based on cuboids is proposed, and then relationship between coverage and sensor nodes’ radius is deduced; also the minimum number of sensor nodes to maintain network area’s full coverage is calculated. At last, sensor nodes are deployed according to the coverage pattern after the monitor area is subdivided into finite 3D grid. Experimental results show that, compared with traditional random method, sensor nodes number is reduced effectively while coverage rate of monitor area is ensured using our coverage pattern and deterministic deployment scheme

    Arecoline induces dual modulation of blood pressure in rat, including an initial downregulation and a subsequent upregulation

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    Purpose: To determine the role of arecoline in cardiovascular modulation in rats.Methods: After rats were anaesthetized with intraperitoneal urethane (1.4 g/kg body weight), saline or arecoline (at doses of 1.0, 3.0 and 10.0 mg/kg) was intraperitoneally administered, and blood pressure (BP) was continuously recorded using a physiological apparatus. Mean arterial pressure (MAP), maximum changes in MAP and reaction time due to arecoline stimulations were calculated and analyzed.Results: Arecoline induced biphasic modulation in BP, including an initial downregulation followed by a subsequent upregulation. The MAP and maximum change in MAP exhibited a concentration-dependent effect in the downregulation phase (p < 0.001 within each group), but not in the upregulation phase (p > 0.05 within each group), while BP reaction time showed a dose-dependent prolongation in both downregulation and upregulation phases (ps < 0.01 within each group). Remarkably, arecoline-induced BP downregulation more rapidly and drastically than upregulation in each arecoline group.Conclusion: These results indicate that arecoline exerts a complex effect in cardiovascular modulation that should be considered as side effects in the clinical use of arecoline and/or with the habitual chewing of areca nuts. Keywords: Arecoline, Blood pressure, Downregulation, Upregulatio

    An Empirical Study of End-to-End Video-Language Transformers with Masked Visual Modeling

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    Masked visual modeling (MVM) has been recently proven effective for visual pre-training. While similar reconstructive objectives on video inputs (e.g., masked frame modeling) have been explored in video-language (VidL) pre-training, previous studies fail to find a truly effective MVM strategy that can largely benefit the downstream performance. In this work, we systematically examine the potential of MVM in the context of VidL learning. Specifically, we base our study on a fully end-to-end VIdeO-LanguagE Transformer (VIOLET), where the supervision from MVM training can be backpropagated to the video pixel space. In total, eight different reconstructive targets of MVM are explored, from low-level pixel values and oriented gradients to high-level depth maps, optical flow, discrete visual tokens, and latent visual features. We conduct comprehensive experiments and provide insights into the factors leading to effective MVM training, resulting in an enhanced model VIOLETv2. Empirically, we show VIOLETv2 pre-trained with MVM objective achieves notable improvements on 13 VidL benchmarks, ranging from video question answering, video captioning, to text-to-video retrieval.Comment: CVPR'23; the first two authors contributed equally; code is available at https://github.com/tsujuifu/pytorch_empirical-mv

    Extensive tRNA gene changes in synthetic Brassica napus

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    Allopolyploidization, where two species come together to form a new species, plays a major role in speciation and genome evolution. Transfer RNAs (abbreviated tRNA) are typically 73-94 nucleotides in length, and are indispensable in protein synthesis, transferring amino acids to the cell protein synthesis machinery (ribosome). To date, the regularity and function of tRNA gene sequence variation during the process of allopolyploidization have not been well understood. In this study, the inter-tRNA gene corresponding to tRNA amplification polymorphism method was used to detect changes in tRNA gene sequences in the progeny of interspecific hybrids between Brassica rapa and B. oleracea, mimicking the original B. napus (canola) species formation event. Cluster analysis showed that tRNA gene variation during allopolyploidization did not appear to have a genotypic basis. Significant variation occurred in the early generations of synthetic B. napus (F and F generations), but fewer alterations were observed in the later generation (F). The variation-prone tRNA genes tended to be located in AT-rich regions. BlastN analysis of novel tRNA gene variants against a Brassica genome sequence database showed that the variation of these tRNA-gene-associated sequences in allopolyploidization might result in variation of gene structure and function, e.g., metabolic process and transport
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