Effective synthesis of circRNA via a thermostable T7 RNA polymerase variant as the catalyst

Introduction:Circular RNAs (circRNAs) are endogenous noncoding RNAs (ncRNAs) with transcriptional lengths ranging from hundreds to thousands. circRNAs have attracted attention owing to their stable structure and ability to treat complicated diseases. Our objective was to create a one-step reaction for circRNA synthesis using wild-type T7 RNA polymerase as the catalyst. However, T7 RNA polymerase is thermally unstable, and we streamlined circRNA synthesis via consensus and folding free energy calculations for hotspot selection. Because of the thermal instability, the permuted intron and exon (PIE) method for circRNA synthesis is conducted via tandem catalysis with a transcription reaction at a low temperature and linear RNA precursor cyclization at a high temperature.Methods:To streamline the process, a multisite mutant T7 RNA polymerase (S430P, N433T, S633P, F849I, F880Y, and G788A) with significantly improved thermostability was constructed, and G788A was used.Results:The resulting mutant exhibited stable activity at 45°C for over an hour, enabling the implementation of a one-pot transcription and cyclization reaction. The simplified circRNA production process demonstrated an efficiency comparable to that of the conventional two-step reaction, with a cyclization rate exceeding 95% and reduced production of immunostimulatory dsRNA byproducts

Joint Subtitle Extraction and Frame Inpainting for Videos with Burned-In Subtitles

Subtitles are crucial for video content understanding. However, a large amount of videos have only burned-in, hardcoded subtitles that prevent video re-editing, translation, etc. In this paper, we construct a deep-learning-based system for the inverse conversion of a burned-in subtitle video to a subtitle file and an inpainted video, by coupling three deep neural networks (CTPN, CRNN, and EdgeConnect). We evaluated the performance of the proposed method and found that the deep learning method achieved high-precision separation of the subtitles and video frames and significantly improved the video inpainting results compared to the existing methods. This research fills a gap in the application of deep learning to burned-in subtitle video reconstruction and is expected to be widely applied in the reconstruction and re-editing of videos with subtitles, advertisements, logos, and other occlusions

A 7.62 mm energetic bullet filled with PTFE-Mg-based reactive materials for anti-drone application

To counter thin and lightweight targets such as drone swarms, a specialized design of 7.62 mm energetic bullets has been developed. These bullets utilize reactive materials as the core encased in a copper jacket, offering the advantages of impact-induced energy release, multiple damage, and lightweight. The study involved the preparation of three energetic bullets using the reactive materials (different ratio of PTFE-Mg-Bi2O3 and PTFE-Mg-Bi2O3-W) and systematically evaluating their destructive effect. The results showed that three energetic bullets (EB-A, EB-B, and EB-W) successfully penetrated two-layer stacked 2 mm 50# cold-rolled steel targets, and the respective reaction durations observed during the penetration process were 4.1, 3.5, and 9.2 ms. After armor-piercing, energetic bullets released an amount of chemical energy and produced fragmentation, deflagration reactions, and overpressure destructive effects. To further investigate the damage mechanism of the three reactive material-filled bullets, a detailed analysis of PTFE-Mg-based reactive material, such as reaction energy, burning rate, combustion temperature field, reaction overpressure, was conducted. Our work provides a comprehensive understanding of energy release performance of the reactive materials and damage behavior of the energetic bullets

Effective Synthesis of High-Integrity mRNA Using In Vitro Transcription

mRNA vaccines are entering a period of rapid development. However, their synthesis is still plagued by challenges related to mRNA impurities and fragments (incomplete mRNA). Most impurities of mRNA products transcribed in vitro are mRNA fragments. Only full-length mRNA transcripts containing both a 5′-cap and a 3′-poly(A) structure are viable for in vivo expression. Therefore, RNA fragments are the primary product-related impurities that significantly hinder mRNA efficacy and must be effectively controlled; these species are believed to originate from either mRNA hydrolysis or premature transcriptional termination. In the manufacturing of commercial mRNA vaccines, T7 RNA polymerase-catalyzed in vitro transcription (IVT) synthesis is a well-established method for synthesizing long RNA transcripts. This study identified a pivotal domain on the T7 RNA polymerase that is associated with erroneous mRNA release. By leveraging the advantageous properties of a T7 RNA polymerase mutant and precisely optimized IVT process parameters, we successfully achieved an mRNA integrity exceeding 91%, thereby further unlocking the immense potential of mRNA therapeutics

Secondary recrystallization of {310}<001> texture and enhanced magnetostriction in Fe–Ga alloy thin sheet

Sharp {310} texture and enhanced magnetostriction were achieved in Fe–Ga thin sheets by secondary recrystallization. The evolution of texture, inhibitor, and magnetostriction of Fe–Ga thin sheet during the annealing process were analyzed. A fine and homogeneous microstructure with a strong γ-fiber and weak Goss and {310} texture was produced. Goss and {310} texture did not exhibit any advantage in terms of the grain size and number over the matrix grains in the primary recrystallization, but {310} texture is superior to Goss texture in grain size and number. Statistical results show that a large number of MnS and NbC precipitates with the size range of 20–140 nm dispersedly distributed in the primary matrix grains thus inhibiting the normal grain growth of primary grains sufficiently. The microstructure and texture evolution during the annealing process indicates that the secondary recrystallization of {310} texture is related to the combination of grain size, quantity, and high energy grain boundary characteristic of {310} texture. The secondary recrystallization of {310} texture is conducive to the improvement of the magnetostrictive coefficient and a maximum magnetostriction of 240 ppm was obtained in Fe–Ga thin sheet after final annealing

Comparative Genomic Analysis of SAUR Gene Family, Cloning and Functional Characterization of Two Genes (PbrSAUR13 and PbrSAUR52) in Pyrus bretschneideri

The SAUR (small auxin-up RNA) gene family is the biggest family of early auxin response genes in higher plants and has been associated with the control of a variety of biological processes. Although SAUR genes had been identified in several genomes, no systematic analysis of the SAUR gene family has been reported in Chinese white pear. In this study, comparative and systematic genomic analysis has been performed in the SAUR gene family and identified a total of 116 genes from the Chinese white pear. A phylogeny analysis revealed that the SAUR family could be classified into four groups. Further analysis of gene structure (introns/exons) and conserved motifs showed that they are diverse functions and SAUR-specific domains. The most frequent mechanisms are whole-genome duplication (WGD) and dispersed duplication (DSD), both of which may be important in the growth of the SAUR gene family in Chinese white pear. Moreover, cis-acting elements of the PbrSAUR genes were found in promoter regions associated with the auxin-responsive elements that existed in most of the upstream sequences. Remarkably, the qRT-PCR and transcriptomic data indicated that PbrSAUR13 and PbrSAUR52 were significantly expressed in fruit ripening. Subsequently, subcellular localization experiments revealed that PbrSAUR13 and PbrSAUR52 were localized in the nucleus. Moreover, PbrSAUR13 and PbrSAUR52 were screened for functional verification, and Dangshan pear and frandi strawberry were transiently transformed. Finally, the effects of these two genes on stone cells and lignin were analyzed by phloroglucinol staining, Fourier infrared spectroscopy, and qRT-PCR. It was found that PbrSAUR13 promoted the synthesis and accumulation of stone cells and lignin, PbrSAUR52 inhibited the synthesis and accumulation of stone cells and lignin. In conclusion, these results indicate that PbrSAUR13 and PbrSAUR52 are predominantly responsible for lignin inhibit synthesis, which provides a basic mechanism for further study of PbrSAUR gene functions

Recent Advances in Perovskite Catalysts for Efficient Overall Water Splitting

Hydrogen is considered a promising clean energy vector with the features of high energy capacity and zero-carbon emission. Water splitting is an environment-friendly and effective route for producing high-purity hydrogen, which contains two important half-cell reactions, namely, the anodic oxygen evolution reaction (OER) and the cathodic hydrogen evolution reaction (HER). At the heart of water splitting is high-performance electrocatalysts that efficiently improve the rate and selectivity of key chemical reactions. Recently, perovskite oxides have emerged as promising candidates for efficient water splitting electrocatalysts owing to their low cost, high electrochemical stability, and compositional and structural flexibility allowing for the achievement of high intrinsic electrocatalytic activity. In this review, we summarize the present research progress in the design, development, and application of perovskite oxides for electrocatalytic water splitting. The emphasis is on the innovative synthesis strategies and a deeper understanding of structure–activity relationships through a combination of systematic characterization and theoretical research. Finally, the main challenges and prospects for the further development of more efficient electrocatalysts based on perovskite oxides are proposed. It is expected to give guidance for the development of novel non-noble metal catalysts in electrochemical water splitting

The value of periportal hyperintensity sign from gadobenate dimeglumine-enhanced hepatobiliary phase MRI for predicting clinical outcomes in patients with decompensated cirrhosis

Abstract Objectives To determine the value of periportal hyperintensity sign from gadobenate dimeglumine (Gd-BOPTA)-enhanced hepatobiliary phase (HBP) magnetic resonance imaging (MRI) for predicting clinical outcomes in patients with decompensated cirrhosis. Methods A total of 199 cirrhotic patients who underwent Gd-BOPTA-enhanced MRI were divided into control group (n  =  56) and decompensated cirrhosis group (n  =  143). The presence of periportal hyperintensity sign on HBP MRI was recorded. The Cox regression model was used to investigate the association between periportal hyperintensity sign and clinical outcomes. Results There was a significant difference in the frequency of periportal hyperintensity sign on HBP between compensated and decompensated cirrhotic patients (p  <  0.05). After a median follow-up of 29.0 months (range, 1.0–90.0 months), nine out of 143 patients (6.2%) with decompensated cirrhosis died. Periportal hyperintensity sign on HBP MRI was a significant risk factor for death (hazard ratio (HR)  =  23.677; 95% confidence interval (CI)  =  4.759–117.788; p  =  0.0001), with an area under the curve (AUC) of 0.844 (95% CI  =  0.774–0.899). Thirty patients (20.9%) developed further decompensation. Periportal hyperintensity sign on HBP MRI was also a significant risk factor for further decompensation (HR  =  2.594; 95% CI  =  1.140–5.903; p  =  0.023). Conclusions Periportal hyperintensity sign from Gd-BOPTA-enhanced HBP MRI is valuable for predicting clinical outcomes in patients with decompensated cirrhosis. Critical relevance statement Periportal hyperintensity sign from gadobenate dimeglumine-enhanced hepatobiliary phase magnetic resonance imaging is a new noninvasive method to predict clinical outcomes in patients with decompensated cirrhosis. Key points • There was a significant difference in the frequency of periportal hyperintensity sign on HBP between compensated and decompensated cirrhotic patients. • Periportal hyperintensity sign on the hepatobiliary phase was a significant risk factor for death in patients with decompensated cirrhosis. • Periportal hyperintensity sign on the hepatobiliary phase was a significant risk factor for further decompensation in patients with decompensated cirrhosis. Graphical Abstrac