Publications by authors named "Chengkun He"

Toxic emission from industrial activity is a serious problem, particularly with regard to the quality of water. Thus, the ISO 11348-3 standard for assessing water quality has been established. This method is used to determine solution toxicity from the bioluminescence inhibition of Aliivibrio fischeri.

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Electrosynthesis has made a revival in the field of organic chemistry and, in particular, radical-mediated reactions. Herein, we report a simple directed, electrochemical C-H fluorination method. Employing a dabconium mediator, commercially available Selectfluor, and RVC electrodes, we provide a range of steroid-based substrates with competent regioselective directing groups, including enones, ketones, and hydroxy groups, as well as never reported before lactams, imides, lactones, and esters.

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Autonomous emergency braking (AEB) systems are able to control vehicles as needed to avoid vehicle rear-end collisions. However, these systems are ineffective in scenarios with laterally cut-in vehicles and rapidly-changing dangerous scenes. This paper proposes a novel collision-free emergency braking system (CFEBS) that can enable intelligent connected vehicles (CAVs) to plan and execute a more conservative safety trajectory for the braking process in dangerous scenes by considering the longitudinal and lateral motion intentions of the surrounding vehicles.

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T-bone collision constitutes an emergency crash scenario that results in casualties and heavy losses; it is an excessively complicated scenario that cannot be handled by conventional control systems. This paper presents an innovative crash mitigation controller for application during unavoidable T-bone collisions to expand the vehicle-maneuverability envelope and minimize crash severity; this controller combines prior knowledge using an optimum expert-behavior policy and drift-operation mechanism based on an improved reinforcement learning algorithm, TD3. Vehicle and tire modeling are performed considering the nonlinear and coupled dynamics characteristics to improve control accuracy.

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Microfluidic devices are widely used in single-cell capture and for pairing single cells or groups of cells for cell-cell interaction analysis; these advances have improved drug screening and cell signal transduction analysis. The complex environment involves interactions between two cells and among multiple cells of the same or different phenotypes. This study reviewed the core principles and performance of several microfluidic multiple- and single-cell capture methods, namely, the microwell, valve, trap, and droplet methods.

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Exploring the drift maneuver could extend the dynamic control envelope and application range of autonomous vehicles. This paper presents a novel autonomous drift controller for a distributed drive electric vehicle, whose configuration provides more possibilities for drift. In the upper-level controller, a control channel recombination method transforms the over-actuated system into a standard square system, which is compatible with the proposed fuzzy-integral sliding-mode controller considering the input coupling and uncertain disturbance of the system to bring the vehicle into a marginally stable condition.

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Besides tumor hypoxia and limitation of superficial lesions, the short lifetime of photoinduced reactive oxygen species (ROS) is another factor repressing photodynamic therapy (PDT) efficacy. To overcome these problems, this study developed newly designed mitochondria-specific, HO-activatable, and O-producing nanoparticles to achieve highly selective and efficient PDT and self-sufficiency of O in hypoxic tumors. The newly designed nanoparticles (BDPP NPs) are composed of a mitochondria-targeting photosensitizer and catalase in the aqueous core and a black hole quencher and fluorescent tracker in the polymeric shell, and modified with the tumor-targeting cyclic pentapeptide c(RGDfK).

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Cell co-culture assays have been widely used for studying cell-cell interactions between different cell types to better understand the biology of diseases including cancer. However, it is challenging to clarify the complex mechanism of intercellular interactions in highly heterogeneous cell populations using conventional co-culture systems because the heterogeneity of the cell subpopulation is obscured by the average values; the conventional co-culture systems can only be used to describe the population signal, but are incapable of tracking individual cells behavior. Furthermore, conventional single-cell experimental methods have low efficiency in cell manipulation because of the Poisson distribution.

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Because of limitations in the current understanding of the exact pathogenesis of tendinopathy, and the lack of an optimal experimental model, effective therapy for the disease is currently unavailable. This study aims to prove that repression of oxidative stress modulates the differentiation of tendon-derived cells (TDCs) sustaining excessive tensile strains, and proposes a novel bioreactor capable of applying differential tensile strains to cultured cells simultaneously. TDCs, including tendon-derived stem cells, tenoblasts, tenocytes, and fibroblasts, were isolated from the patellar tendons of Sprague‒Dawley rats.

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Studies on cellular heterogeneity have emerged as a powerful approach for developing new strategies to treat diseases including cancer. However, it is difficult to set up an in vitro co-culture experiment to study the interaction of individual live cells. In this paper, we report a hydrodynamic shuttling chip (HSC) which can deterministically capture single cells into microfluidic chambers to set up multiple single-cell co-culture experiments in which individual live cells can be microscopically observed.

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This study addresses T-DNA insert stability and transgene expression consistency in multiple cycles of field propagated sugarcane. T-DNA inserts are stable; no transgene rearrangements were observed. AmCYAN1 and PMI protein accumulation levels were maintained.

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Article Synopsis
  • In vitro culture of single cells helps researchers study biological processes without the interference of mixed cell populations, but current methods are not efficient enough for high-throughput experiments.
  • This paper presents a microfluidic device with a dual-well design that achieves a high cell loading yield (~77%) in large microwells, supporting cell spreading, proliferation, and differentiation.
  • The innovative device uses "capture-wells" for single-cell capture and "culture-wells" for growth, allowing flexibility in well size while maintaining efficiency, as shown in experiments with various cell types.
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In recent years, there has been a rapid increase in the planting of transgenic crops with stacked traits. Most of these products have been formed by conventional breeding, i.e.

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To identify minimal effective promoters for driving abiotic stress-inducible transgene expression in rice, we selected promoter elements of three stress-responsive genes, viz. rab16A coding for dehydrin, OsABA2 coding for zeaxanthin epoxidase, and a gene coding for a hypothetical protein (HP1) based on the presence of ABA-, salt- and drought-responsive cis-acting elements. These were translationally fused to the gusA reporter gene and introduced into rice to study their effect on heterologous gene expression.

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We have isolated and characterized the 5' region of the rice actin2 gene (OsAct2), which contains 793 bp of sequence upstream of the OsAct2 transcription initiation site, 58 bp of the first non-coding exon, 1736 bp of the 5' intron and the first 8 bp (non-coding sequence) of the second exon. It was found that the 5' region of OsAct2 is an efficient gene regulatory region for driving the constitutive expression of foreign genes in transgenic rice. In situ histochemical results indicated that OsAct2::GUS (GUS, beta-glucuronidase) gene expression in transgenic rice plants is high in sporophytic and gametophytic tissues.

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An efficient system was developed, and several variables tested, for generating a large-scale insertional-mutagenesis population of rice. The most important feature in this improved Ac/Ds tagging system is that one can conveniently carry out large-scale screening in the field and select transposants at the seedling stage. Rice was transformed with a plasmid that includes a Basta-resistance gene (bar).

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Generation of an indexed, saturated, insertional-mutant library is an aid to understanding the functions of genes in an organism. However, 10 years of work by many investigators have not yet yielded such a library in rice. The major reason is that determining the chromosomal locations of a very large number of random insertion mutants by flanking sequence analysis is highly labor intensive, and therefore, libraries that do exist have not been indexed.

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Glycine betaine (GB) is a compatible solute that is also capable of stabilizing the structure and function of macromolecules. Several GB-producing transgenic rice lines were generated in which the Arthrobacter pascens choline oxidase (COX) gene, fused to a chloroplast targeting sequence (TP) was expressed under the control of an ABA-inducible promoter (SIP; stress-inducible promoter) or a ubiquitin (UBI) gene promoter that is considered to be constitutive. This comparison led to interesting observations that suggest complex regulation with respect to GB synthesis and plant growth response under stress.

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