Search

It is expected that fusion energy development, which is at a critical stage of breaking through energy break-even in the engineering sense, has the potential to reshape the future pattern of energy development with both opportunities and challenges. This study reviews the main progress of fusion energy research and summarizes the major challenges regarding energy balance, tritium selfsustainability, high availability, development of irradiation-resistant materials, and economical efficiency in general sense. On the basis of sorting out the common basic technology breakthroughs of the International Thermonuclear Experimental Reactor (ITER) program and the supporting research activities of its member states, the study summarizes the progress of China’s magnetic confinement fusion research in terms of overall planning, self-developed projects, and technical tracking. Furthermore, focusing on the Z-pinch-driven fusion-fission hybrid reactor (Z-FFR) concept, which is independently proposed by China, this study elaborates on the basic principles, application advantages, and series of progresses, and proposes a development plan toward commercial energy supply by 2040, covering the task objectives in the stages of key technology campaign, engineering demonstration, and promotion of commercial power generation. To comprehensively promote China’s fusion energy development, several suggestions are given. In the magnetic confinement fusion area, it is suggest that China deeply participate in the ITER program and relevant international cooperation, overcome key physics and engineering technologies of commercial fusion reactors, promote the research and development of key components of China Fusion Engineering Test Reactor (CFETR) device, and construct and operate CFETR in due course. In the Z-FFR area, it is of first priority to start the construction of electromagnetic-driven large-scale scientific devices the soonest possible, develop key technologies for fusion energy, and promote both engineering demonstrations and commercial projects in proper time.

The informatization and intelligence of wind farm lock and key management is the key to further improve the level of wind farm operation and maintenance management. This paper designs a smart key security management and control architecture for wind farms. Combined with the proposed short-range wireless communication anti-jamming technology, key encryption, and dynamic attack detection technology, a set of wind farm smart key security management and control system has been developed. The system can realize the functions of opening and closing information traceability and risk prevention, etc., which improves the network, digital and intelligent level of wind farm operation and maintenance.

The properties of the failure shots on an induction voltage adder are described. This induction voltage adder is composed of six identical prime pulsed power sources, six induction cavities, and a lossless vacuum insulation output transmission line which is terminated by a rod-pinch diode. The failure modes include too early and too late firing of the laser-triggered gas switch in the prime pulsed power sources and abnormal diode impedance declining. The amplitudes of the voltage pulses across the feed port and azimuthal transmission line of the induction cavity are increased by 38% and 48%, respectively, in the event that this cell is driven too early. On the contrary, a reverse voltage pulse will be produced at the induction cavity when it is fired too late. The peak value of the reverse voltage pulse is about 50% of that of the normal polarity pulse. The abnormal rod-pinch diode impedance declining taking place occasionally decreases the load voltage and x-ray dose remarkably. However, the average amplitude of the voltage pulses across the six induction cavities is almost the same as that of a normal shot. We have also analyzed the property of the voltage pulses across the induction cell under the circumstance that only one induction cavity is fired. Both the experimental and circuit simulation data suggest that in this case the voltage pulses on the induction cell are nearly identical even though the load impedance varies vastly.

The design and test results of a pulsed power-driven X-ray source which is named Hawkeye-I are described. The Hawkeye-I is developed to execute flash X-ray radiography. It is a six-stage induction voltage adder and terminated by a positive polarity rod-pinch diode. The six stages are identical and the prime energy of each stage is provided by a tesla transformer elevating the output voltage from a discharge brick which consists of two 4 μF capacitors and a three-electrode gas switch. Comparing to the induction voltage adders driven by Marx generators, the numbers of gas switches and capacitors in the energy storage sections of Hawkeye-I decrease significantly. The Hawkeye-I can produce a maximum output voltage of about 4.2 MV. The corresponding X-ray source spot size and dose at 1 m are 1.4 mm and 17.9 rad, respectively. Fifty consecutive shots have been conducted to evaluate the reliability of the machine and 98% of the shots are successful. Furthermore, as the energy propagating in the accelerator is mainly determined by seven laser-triggered gas switches, the Hawkeye-I is capable of controlling the timing of the X-ray pulse accurately.

The recent pandemic of variants of concern (VOC) of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) highlights the need for innovative anti‐SARS‐CoV‐2 approaches in addition to vaccines and antiviral therapeutics. Here, we demonstrate that a CRISPR‐Cas13‐based strategy against SARS‐CoV‐2 can effectively degrade viral RNA. First, we conducted a cytological infection experiment, screened CRISPR‐associated RNAs (crRNAs) targeting conserved regions of viruses, and used an in vitro system to validate functional crRNAs. Reprogrammed Cas13d effectors targeting NSP13, NSP14, and nucleocapsid transcripts achieved >99% silencing efficiency in human cells which are infected with coronavirus 2, including the emerging variants in the last 2 years, B.1, B.1.1.7 (Alpha), D614G B.1.351 (Beta), and B.1.617 (Delta). Furthermore, we conducted bioinformatics data analysis. We collected the sequence information of COVID‐19 and its variants from China, and phylogenetic analysis revealed that these crRNA oligos could target almost 100% of the SARS‐CoV family, including the emerging new variant, Omicron. The reprogrammed Cas13d exhibited high specificity, efficiency, and rapid deployment properties; therefore, it is promising for antiviral drug development. This system could possibly be used to protect against unexpected SARS‐CoV‐2 variants carrying multiple mutations. [ABSTRACT FROM AUTHOR]

Trophoblast stem cells (TSCs) are derived from blastocysts and the extra-embryonic ectoderm (ExE) of post-implantation embryos and play a significant role in fetal development, but the roles that TSCs play in the earlier status of fetal diseases need further exploration. Super enhancers (SEs) are dense clusters of stitched enhancers that control cell identity determination and disease development and may participate in TSC differentiation. We identified key cell identity genes regulated by TSC-SEs via integrated analysis of H3K27ac and H3K4me1 chromatin immunoprecipitation sequencing (ChIP-seq), RNA-sequencing (RNA-seq) and ATAC-sequencing (ATAC-seq) data. The identified key TSC identity genes regulated by SEs, such as epidermal growth factor receptor (EGFR), integrin β5 (ITGB5) and Paxillin (Pxn), were significantly upregulated during TSC differentiation, and the transcription network mediated by TSC-SEs enriched in terms like focal adhesion and actin cytoskeleton regulation related to differentiation of TSCs. Additionally, the increased chromatin accessibility of the key cell identity genes verified by ATAC-seq further demonstrated the regulatory effect of TSC-SEs on TSC lineage commitment. Our results illustrated the significant roles of the TSC-SE-regulated network in TSC differentiation, and identified key TSC identity genes EGFR, ITGB5 and Pxn, providing novel insight into TSC differentiation and lays the foundation for future studies on embryo implantation and related diseases. [ABSTRACT FROM AUTHOR]

In this paper, the results of tests on a 0.76-TW linear transformer driver (LTD) module for Z-pinch research are presented for the first time. Ten LTD cavities, each generating a 1-MA/90-kV pulse on a matched load, were connected in series with a magnetically insulated voltage adder to drive the e-beam diode. Three inner stalks with different radii were tested, and the results indicate that the output parameters of the ten cavities are sensitive to the cathode radii. As an intermediate step, a high-current pulse with 832 kV/912 kA/130 ns was obtained on the e-beam diode. To date, this is the maximum power generated directly by a fast LTD with mega-ampere current output. [ABSTRACT FROM AUTHOR]

Aerial scene classification, which aims to automatically label an aerial image with a specific semantic category, is one of the most challenging tasks in computer vision. With the improvement of spatial resolution of aerial images, the texture details of ground objects become increasingly abundant. Although many classification algorithms have been proposed in recent years, accuracy and completeness of the classification results are still imperative problems to be solved. We propose an algorithm via a two-stage voting fusion strategy. First, the superpixels obtained by simple linear iterative cluster algorithm are treated as the input of a random forest classifier. Then, the region growth strategy is applied to complete the clustering of similar local regions, and the learning of mosaic zero pieces is simultaneously realized. Finally, a Bayesian framework is exploited to fuse the classification results in order to get the final classification results. Experiments on two benchmarks demonstrate the superiority of the proposed method (TSS) compared with other state-of-the-art methods, whether in terms of the integrity of big targets or the accuracy of small objects. [ABSTRACT FROM AUTHOR]

As a typical deep-learning model, Convolutional Neural Networks (CNNs) can be exploited to automatically extract features from images using the hierarchical structure inspired by mammalian visual system. For image classification tasks, traditional CNN models employ the softmax function for classification. However, owing to the limited capacity of the softmax function, there are some shortcomings of traditional CNN models in image classification. To deal with this problem, a new method combining Biomimetic Pattern Recognition (BPR) with CNNs is proposed for image classification. BPR performs class recognition by a union of geometrical cover sets in a high-dimensional feature space and therefore can overcome some disadvantages of traditional pattern recognition. The proposed method is evaluated on three famous image classification benchmarks, that is, MNIST, AR, and CIFAR-10. The classification accuracies of the proposed method for the three datasets are 99.01%, 98.40%, and 87.11%, respectively, which are much higher in comparison with the other four methods in most cases. [ABSTRACT FROM AUTHOR]

Current as high as 3.7 kA has been generated using a single photoconductive semiconductor switch (PCSS) excited by a laser pulse with the energy of ∼8 mJ and under a bias of 28 kV. The PCSS with electrode gap of 14 mm was fabricated from semi-insulating GaAs. Under different bias voltages the “on” resistances of the PCSS were measured. The longevity of the PCSS reached 350 shots at 20 kV and 400 A. The breakdown mechanism of the PCSS is analyzed based on the breakdown characteristics. It is shown that the breakdown of GaAs PCSS can be described by the electron-trapping breakdown theory. [ABSTRACT FROM AUTHOR]

The biological function of the novel zinc-finger SWIM domain-containing protein family (ZSWIM) during embryonic development remains elusive. Here, we conducted a genome-wide analysis to explore the evolutionary processes of the ZSWIM gene family members in mice, Xenopus tropicalis , zebrafish, and humans. We identified nine putative ZSWIM genes in the human and mouse genome, eight in the Xenopus genome, and five in the zebrafish genome. Based on multiple sequence alignment, three members, ZSWIM5, ZSWIM6, and ZSWIM8, demonstrated the highest homology across all four species. Using available RNA sequencing (RNA-seq) data, ZSWIM genes were found to be widely expressed across different tissues, with distinct tissue-specific properties. To identify the functions of the ZSWIM protein family during embryogenesis, we examined temporal and spatial expression patterns of zswim family genes in Xenopus embryos . Quantitative real-time polymerase chain reaction (qRT-PCR) revealed that each member had a distinct expression profile. Whole-mount in situ hybridization showed that both zswim1 and zswim3 were maternally expressed genes; zswim5 and zswim6 were expressed throughout embryogenesis and displayed dynamic expression in the brain, eyes, somite, and bronchial arch at the late tailbud stages; zswim7 was detected in the eye area; zswim8 showed a dynamic expression pattern during the tailbud stages, with expression detected in the brain, eyes, and somite; zswim9 was faintly expressed throughout embryonic development. This study provides a foundation for future research to delineate the functions of ZSWIM gene members.

Background: Abnormal activation of the NF-κB pathway is closely related to tumorigenesis and chemoresistance. Therefore, microRNAs that possess the NF-κB inhibitory activity may provide novel targets for anti-cancer therapy. miR-26 family members have been shown to be frequently downregulated in hepatocellular carcinoma (HCC) and correlated with the poor survival of HCC patients. To date, there is no report disclosing the regulatory role of miR-26 on the NF-κB pathway and its biological significance., Methods: The effects of miR-26b on the NF-κB signaling pathway and the chemosensitivity of cancer cells were examined in two HCC cell lines, QGY-7703 and MHCC-97H, using both gain- and loss-of-function studies. The correlation between miR-26b level and apoptosis rate was further investigated in clinical HCC specimens., Results: Both TNFα and doxorubicin treatment activated the NF-κB signaling pathway in HCC cells. However, the restoration of miR-26b expression significantly inhibited the phosphorylation of IκBα and p65, blocked the nuclear translocation of NF-κB, reduced the NF-κB reporter activity, and consequently abrogated the expression of NF-κB target genes in TNFα or doxorubicin-treated HCC cells. Furthermore, the ectopic expression of miR-26b dramatically sensitized HCC cells to the doxorubicin-induced apoptosis, whereas the antagonism of miR-26b attenuated cell apoptosis. Consistently, the miR-26b level was positively correlated with the apoptosis rate in HCC tissues. Subsequent investigations revealed that miR-26b inhibited the expression of TAK1 and TAB3, two positive regulators of NF-κB pathway, by binding to their 3'-untranslated region. Moreover, knockdown of TAK1 or TAB3 phenocopied the effects of miR-26b overexpression., Conclusions: These data suggest that miR-26b suppresses NF-κB signaling and thereby sensitized HCC cells to the doxorubicin-induced apoptosis by inhibiting the expression of TAK1 and TAB3. Our findings highlight miR-26b as a potent inhibitor of the NF-κB pathway and an attractive target for cancer treatment.