100 research outputs found
Paths and Mechanisms of Rural Transformation Promoted by Rural Collectively Owned Commercial Construction Land Marketization in China
Rural collectively owned commercial construction land marketization (RCCCLM), a land policy that is still being piloted despite being allowed by law, has been regarded as an indispensable policy tool that can meet the land demand for rural development. This study aims to analyze the typical modes and key paths of RCCCLM for rural transformation theoretically and practically. We developed an innovative theoretical framework of āSituation-Structure-Implementation-Outcomeā to illustrate the relationship between RCCCLM and rural transformation. By tracing the process of the impact of RCCCLM on rural transformation in typical areas, this study fills the gap in existing research that has not yet explored the theoretical mechanisms between RCCCLM and rural transformation. The results show that a combination of such factors as geographical location and rural land use status brings about three major ways of RCCCLM, namely, local marketization, adjustive marketization and consolidation-based marketization, to promote rural transformation. The influencing mechanism of RCCCLM on rural transformation mainly concerns rights granting, rural land use structure reshaping, the transformation of farmersā livelihood and improvement in rural governance capacity. Rural transformation follows a basic rule and phased characteristics of evolving from single function to multiple functions, and RCCCLM displays a differentiated driving effect on the evolution of rural functions in different stages of rural development. These findings will provide new insights into rural land use and rural transformation in China and other developing countries and help solve the bottlenecks in rural transformation
Expounding the role of tick in Africa swine fever virus transmission and seeking effective prevention measures: A review
African swine fever (ASF), a highly contagious, deadly infectious disease, has caused huge economic losses to animal husbandry with a 100% mortality rate of the most acute and acute infection, which is listed as a legally reported animal disease by the World Organization for Animal Health (OIE). African swine fever virus (ASFV) is the causative agent of ASF, which is the only member of the Asfarviridae family. Ornithodoros soft ticks play an important role in ASFV transmission by active biological or mechanical transmission or by passive transport or ingestion, particularly in Africa, Europe, and the United States. First, this review summarized recent reports on (1) tick species capable of transmitting ASFV, (2) the importance of ticks in the transmission and epidemiological cycle of ASFV, and (3) the ASFV strains of tick transmission, to provide a detailed description of tick-borne ASFV. Second, the dynamics of tick infection with ASFV and the tick-induced immune suppression were further elaborated to explain how ticks spread ASFV. Third, the development of the anti-tick vaccine was summarized, and the prospect of the anti-tick vaccine was recapitulated. Then, the marked attenuated vaccine, ASFV-G-ĪI177L, was compared with those of the anti-tick vaccine to represent potential therapeutic or strategies to combat ASF
Fabrications of <i>L</i>-Band LiNbO<sub>3</sub>-Based SAW Resonators for Aerospace Applications
High frequency surface acoustic wave (SAW) technology offers many opportunities for aerospace applications in passive wireless sensing and communication. This paper presents the design, simulation, fabrication, and test of an L-band SAW resonator based on 128° Y-X LiNbO3 substrate. The design parameters of SAW resonator were optimized by the finite element (FEM) method and the coupling-of-mode (COM) theory. Electron-beam lithography (EBL) technology was used to fabricate the submicron-scale of interdigital transducers (IDTs) and grating reflectors. The effects of some key EBL processes (e.g., the use of electron beam resist, the choice of metal deposition methods, the charge-accumulation effect, and the proximity-effect) on the fabrication precision of SAW devices were discussed. Experimentally, the LiNbO3-based SAW resonators fabricated using improved EBL technology exhibits a Rayleigh wave resonance peaks at 1.55 GHz with return loss about −12 dB, and quality factor Q is 517. Based on this SAW resonator, the temperature and strain sensing tests were performed, respectively. The experimental results exhibit a well linear dependence of temperature/strain on frequency-shift, with a temperature sensitivity of 125.4 kHz/°C and a strain sensitivity of −831 Hz/με, respectively
Maximum Entropy Niche-Based Modeling (Maxent) of Potential Geographical Distributions of Lobesia Botrana (Lepidoptera: Tortricidae) in China
Part 1: Simulation, Optimization, Monitoring and Control TechnologyInternational audienceLobesia botrana (Denis & SchiffermĆ¼ller, 1775) (Lepidoptera: Tortricidae) is one of the most destructive pests of grape in the Palearctic region. The potential geographical distribution of this pest is important to agriculture security. In this study, Maxent and ArcGIS were used to project the potential geographical distribution of L. botrana in China under the current climate. The result indicated that L. botrana was suitable in most parts of middle and southern China and the Maxent model was highly accurate for the AUC value of 0.970. Jackknife analysis revealed that low temperature influence the potential distribution of L. botrana. This study would be a decision-support of surveillance and quarantine measures
Custom-made electrochemical energy storage devices
A customizable electrochemical energy storage device is a key component for the realization of next-generation wearable and biointegrated electronics. This Perspective begins with a brief introduction of the drive for customizable electrochemical energy storage devices. It traces the first-decade development trajectory of the customizable electrochemical energy storage devices. It then discusses the challenges and future directions, calling for such devices that allow users to select, design, and change the properties (including capacity, flexibility, shapes, and functionalities) according to real-life needs. Leveraging these customizable electrochemical energy storage devices will shed light on smarter programmable electrochemical energy storage devices to power future wearable and biointegrated electronics.Accepted versio
Efficacy analysis of hybrid operating room-based laparoscopic cholecystectomy combined with intraoperative endoscopic retrograde cholangiopancreatography in the treatment of cholelithiasis combined with choledocholithiasis ā A caseācontrol study
Objective: The objective is to compare the therapeutic effects of laparoscopic cholecystectomy (LC) combined with intraoperative endoscopic retrograde cholangiopancreatography (ERCP) in hybrid operating room and ERCP + LC under traditional conditions in the treatment of cholelithiasis and choledocholithiasis.
Materials and Methods: Data of 82 patients with cholelithiasis complicated with choledocholithiasis treated by our centre from November 2018 to March 2021 were retrospectively analysed. Amongst them, 40 patients treated with LC combined with intraoperative ERCP in a hybrid operating room were placed into Group A, and 42 patients treated with ERCP first followed by LC under traditional conditions were placed into Group B. The differences in operative time, intraoperative blood loss, surgical success rate, stone clearance rate, pain score, exhaust time, ambulation time, post-operative complications, length of hospital stay, hospitalisation cost and other indicators between the two groups were compared.
Results: There were no significant differences in operative time, intraoperative blood loss, surgical success rate and stone clearance rate between the two groups (P > 0.05), while there were significant differences in post-operative pain score, exhaust time, ambulation time, length of hospital stay, hospitalisation cost and complications (P < 0.05).
Conclusion: LC combined with intraoperative ERCP in hybrid operating room for the treatment of cholelithiasis combined with choledocholithiasis has a better therapeutic effect than traditional ERCP followed by LC, which is worthy of further popularization. Notably, the reasonable selection should be made based on patients' own conditions and hospital facilities
A Deconvolution Technology of Microwave Radiometer Data Using Convolutional Neural Networks
Microwave radiometer data is affected by many factors during the imaging process, including the antenna pattern, system noise, and the curvature of the Earth. Existing deconvolution methods such as Wiener filtering handle this degradation problem in the Fourier domain. However, under complex degradation conditions, the Wiener filtering results are not accurate. In this paper, a convolutional neural network (CNN) model is proposed to solve the degradation problem. The deconvolution procedure is defined as a regression problem in the spatial domain that can be solved with deep learning. For the real inverse process of microwave radiometer data, the CNN model has a more powerful reconstruction ability than Wiener filtering due to the multi-layer structure of the CNN, which enables the multiple feature transform of the data. Additionally, the complex degradation factor during the imaging process of a microwave radiometer can be solved with general framework-based learning. Experimental results demonstrated that the CNN model gains about 5 dB at the peak signal-to-noise ratio compared to the Wiener filtering deconvolution method, and can better distinguish the measured data
Combinatorial pathway enzyme engineering and host engineering overcomes pyruvate overflow and enhances overproduction of N-acetylglucosamine in Bacillus subtilis
Abstract Background Glucosamine-6-phosphate N-acetyltransferase (GNA1) is the key enzyme that causes overproduction of N-acetylglucosamine in Bacillus subtilis. Previously, we increased GlcNAc production by promoting the expression of GNA1 from Caenorhabditis elegans (CeGNA1) in an engineered B. subtilis strain BSGN12. In this strain overflow metabolism to by-products acetoin and acetate had been blocked by mutations, however pyruvate accumulated as an overflow metabolite. Although overexpression of CeGNA1 drove carbon flux from pyruvate to the GlcNAc synthesis pathway and decreased pyruvate accumulation, the residual pyruvate reduced the intracellular pH, resulting in inhibited CeGNA1 activity and limited GlcNAc production. Results In this study, we attempted to further overcome pyruvate overflow by enzyme engineering and host engineering for enhanced GlcNAc production. To this end, the key enzyme CeGNA1 was evolved through error-prone PCR under pyruvate stress to enhance its catalytic activity. Then, the urease from Bacillus paralicheniformis was expressed intracellularly to neutralize the intracellular pH, making it more robust in growth and more efficient in GlcNAc production. It was found that the activity of mutant CeGNA1 increased by 11.5% at pH 6.5ā7.5, with the catalytic efficiency increasing by 27.5% to 1.25Ā sā1Ā ĀµMā1. Modulated expression of urease increased the intracellular pH from 6.0 to 6.8. The final engineered strain BSGN13 overcame pyruvate overflow, produced 25.6Ā g/L GlcNAc with a yield of 0.43Ā g GlcNAc/g glucose in a shake flask fermentation and produced 82.5Ā g/L GlcNAc with a yield of 0.39Ā g GlcNAc/g glucose by fed-batch fermentation, which was 1.7- and 1.2-times, respectively, of the yield achieved previously. Conclusions This study highlights a strategy that combines pathway enzyme engineering and host engineering to resolve overflow metabolism in B. subtilis for the overproduction of GlcNAc. By means of modulated expression of urease reduced pyruvate burden, conferred bacterial survival fitness, and enhanced GlcNAc production, all of which improved our understanding of co-regulation of cell growth and metabolism to construct more efficient B. subtilis cell factories
Process optimization for the production of high-concentration ethanol with Scenedesmus raciborskii biomass
Scenedesmus raciborskii WZKMT was subjected to fed-batch enzymatic hydrolysis and fermentation to facilitate the saccharification of high-solid-loading substrate for high-concentration ethanol. In this work, process factors affecting enzymatic hydrolysis, including enzyme loading, temperature, pH, and solid loading, were optimized. Results showed that 58.03 g L-1 glucose, 12.57 g L-1 xylose, and 1.45 g L-1 cellobiose were obtained after the enzymatic hydrolysis of 330 g L-1 substrates under the optimal conditions of 30 FPU g(-1) enzyme loading, 50 degrees C, and pH 5.5. Meanwhile, 89.60% yield and 30.43 g L-1 content of ethanol were obtained after the fermentation of 330 g L-1 hydrolysate. The maximum ethanol concentration of 79.38 g L-1 could be achieved through repeated fed-batch process, indicating that S. raciborskii WZKMT is a promising feedstock for ethanol production
Test and Application of Shut-in and Step-down Adjustment Technology for Injection Well and Drilling Process
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