In the context of emerging engineering disciplines,a hybrid teaching reform for the Bioengineering Downstream Technology course,based on ideological and political education and online open courses,is being carried out...In the context of emerging engineering disciplines,a hybrid teaching reform for the Bioengineering Downstream Technology course,based on ideological and political education and online open courses,is being carried out.This reform focuses on aspects such as“building a professional teacher team for ideological and political education,scientifically designing the ideological and political teaching system,innovating classroom teaching methods,and improving both formative and summative evaluation systems.”The“Craftsmanship in Education and Cultivating Soul and Roots”small private online course hybrid teaching reform for the Bioengineering Downstream Technology online open course provides a replicable model for the comprehensive implementation of ideological and political education in engineering courses and offers a reference for advancing ideological and political education and hybrid teaching reform in new engineering disciplines.展开更多
Peripheral nerve injuries remain a challenging problem in need of better treatment strategies.Despite best efforts at surgical reconstruction and postoperative rehabilitation,patients are often left with persistent,de...Peripheral nerve injuries remain a challenging problem in need of better treatment strategies.Despite best efforts at surgical reconstruction and postoperative rehabilitation,patients are often left with persistent,debilitating motor and sensory deficits.There are currently no therapeutic strategies proven to enhance the regenerative process in humans.A clinical need exists for the development of technologies to promote nerve regeneration and improve functional outcomes.Recent advances in the fields of tissue engineering and nanotechnology have enabled biomaterial scaffolds to modulate the host response to tissue repair through tailored mechanical,chemical,and conductive cues.New bioengineered approaches have enabled targeted,sustained delivery of protein therapeutics with the capacity to unlock the clinical potential of a myriad of neurotrophic growth factors that have demonstrated promise in enhancing regenerative outcomes.As such,further exploration of combinatory strategies leveraging these technological advances may offer a pathway towards clinically translatable solutions to advance the care of patients with peripheral nerve injuries.This review first presents the various emerging bioengineering strategies that can be applied for the management of nerve gap injuries.We cover the rationale and limitations for their use as an alternative to autografts,focusing on the approaches to increase the number of regenerating axons crossing the repair site,and facilitating their growth towards the distal stump.We also discuss the emerging growth factor-based therapeutic strategies designed to improve functional outcomes in a multimodal fashion,by accelerating axonal growth,improving the distal regenerative environment,and preventing end-organs atrophy.展开更多
Liver transplantation is the only curative therapy for end stage liver disease,but is limited by the organ shortage,and is associated with the adverse consequences of immunosuppression.Repopulation of decellularised w...Liver transplantation is the only curative therapy for end stage liver disease,but is limited by the organ shortage,and is associated with the adverse consequences of immunosuppression.Repopulation of decellularised whole organ scaffolds with appropriate cells of recipient origin offers a theoretically attractive solution,allowing reliable and timely organ sourcing without the need for immunosuppression.Decellularisation methodologies vary widely but seek to address the conflicting objectives of removing the cellular component of tissues whilst keeping the 3D structure of the extra-cellular matrix intact,as well as retaining the instructive cell fate determining biochemicals contained therein.Liver scaffold recellularisation has progressed from small rodent in vitro studies to large animal in vivo perfusion models,using a wide range of cell types including primary cells,cell lines,foetal stem cells,and induced pluripotent stem cells.Within these models,a limited but measurable degree of physiologically significant hepatocyte function has been reported with demonstrable ammonia metabolism in vivo.Biliary repopulation and function have been restricted by challenges relating to the culture and propagations of cholangiocytes,though advances in organoid culture may help address this.Hepatic vasculature repopulation has enabled sustainable blood perfusion in vivo,but with cell types that would limit clinical applications,and which have not been shown to have the specific functions of liver sinusoidal endothelial cells.Minority cell groups such as Kupffer cells and stellate cells have not been repopulated.Bioengineering by repopulation of decellularised scaffolds has significantly progressed,but there remain significant experimental challenges to be addressed before therapeutic applications may be envisaged.展开更多
The Tianma 65 m radio telescope(TMRT)at Shanghai is a fully steerable single-dish radio telescope in China,operating at centimeter to millimeter wavelengths(1.25 GHz to 50 GHz).This paper presents details on the main ...The Tianma 65 m radio telescope(TMRT)at Shanghai is a fully steerable single-dish radio telescope in China,operating at centimeter to millimeter wavelengths(1.25 GHz to 50 GHz).This paper presents details on the main specifications,design,performance analysis,testing,and construction of the telescope antenna.The measured total efficiency is better than 50%over the whole elevation angle range,first sidelobe levels are less than−20 dB,antenna system noise temperatures are less than 70 K at 30°elevation angle,and pointing accuracy is less than 3″.The measured and calculated results are in good agreement,verifying the effectiveness of the design and analysis.展开更多
The identification of intercepted radio fuze modulation types is a prerequisite for decision-making in interference systems.However,the electromagnetic environment of modern battlefields is complex,and the signal-to-n...The identification of intercepted radio fuze modulation types is a prerequisite for decision-making in interference systems.However,the electromagnetic environment of modern battlefields is complex,and the signal-to-noise ratio(SNR)of such environments is usually low,which makes it difficult to implement accurate recognition of radio fuzes.To solve the above problem,a radio fuze automatic modulation recognition(AMR)method for low-SNR environments is proposed.First,an adaptive denoising algorithm based on data rearrangement and the two-dimensional(2D)fast Fourier transform(FFT)(DR2D)is used to reduce the noise of the intercepted radio fuze intermediate frequency(IF)signal.Then,the textural features of the denoised IF signal rearranged data matrix are extracted from the statistical indicator vectors of gray-level cooccurrence matrices(GLCMs),and support vector machines(SVMs)are used for classification.The DR2D-based adaptive denoising algorithm achieves an average correlation coefficient of more than 0.76 for ten fuze types under SNRs of-10 d B and above,which is higher than that of other typical algorithms.The trained SVM classification model achieves an average recognition accuracy of more than 96%on seven modulation types and recognition accuracies of more than 94%on each modulation type under SNRs of-12 d B and above,which represents a good AMR performance of radio fuzes under low SNRs.展开更多
Mainstream media play a crucial role in constructing the cultural memory of a city.This study used 319 short videos released by“Hi Chengdu,”a new media product of Chengdu Radio and Television,as samples.Based on the...Mainstream media play a crucial role in constructing the cultural memory of a city.This study used 319 short videos released by“Hi Chengdu,”a new media product of Chengdu Radio and Television,as samples.Based on the grounded theory,a research framework encompassing“content,technology,and discourse”was established to explore the paths through which mainstream media construct the cultural memory.Regarding content,this paper emphasized temporal and spatial contexts and urban spaces,delving deep into the themes of the cultural memory and vehicles for it.In terms of technology,this paper discussed the practice of leveraging audio/visual-mode discourse to stitch together the impressions of a city and evoke emotional resonance to create a“flow”of memory.As for discourse,this paper looked at the performance of a communication ritual to frame concepts and shape urban identity.It is essential to break free from conventional thinking and leverage local culture as the primary driving force to further boost a city’s productivity,in order to excel in cultural communication.展开更多
We present an independent catalog(FRIIRGcat)of 45,241 Fanaroff–Riley TypeⅡ(FR-Ⅱ)radio galaxies compiled from the Very Large Array Faint Images of the Radio Sky at Twenty-centimeters(FIRST)survey and employed the de...We present an independent catalog(FRIIRGcat)of 45,241 Fanaroff–Riley TypeⅡ(FR-Ⅱ)radio galaxies compiled from the Very Large Array Faint Images of the Radio Sky at Twenty-centimeters(FIRST)survey and employed the deep learning method.Among them,optical and/or infrared counterparts are identified for 41,425 FR-Ⅱs.This catalog spans luminosities 2.63×10^(22)≤L_(rad)≤6.76×10^(29)W Hz^(-1)and redshifts up to z=5.01.The spectroscopic classification indicates that there are 1431 low-excitation radio galaxies and 260 high-excitation radio galaxies.Among the spectroscopically identified sources,black hole masses are estimated for 4837 FR-Is,which are in 10^(7.5)■M_(BH)■10^(9.5)M_(⊙).Interestingly,this catalog reveals a couple of giant radio galaxies(GRGs),which are already in the existing GRG catalog,confirming the efficiency of this FR-I catalog.Furthermore,284new GRGs are unveiled in this new FR-I sample;they have the largest projected sizes ranging from 701 to1209 kpc and are located at redshifts 0.31<z<2.42.Finally,we explore the distribution of the jet position angle and it shows that the faint Images of the FIRST images are significantly affected by the systematic effect(the observing beams).The method presented in this work is expected to be applicable to the radio sky surveys that are currently being conducted because they have finely refined telescope arrays.On the other hand,we are expecting that further new methods will be dedicated to solving this problem.展开更多
Fast radio bursts(FRBs)are among the most studied radio transients in astrophysics,but their origin and radiation mechanism are still unknown.It is a challenge to search for FRB events in a huge amount of observationa...Fast radio bursts(FRBs)are among the most studied radio transients in astrophysics,but their origin and radiation mechanism are still unknown.It is a challenge to search for FRB events in a huge amount of observational data with high speed and high accuracy.With the rapid advancement of the FRB research process,FRB searching has changed from archive data mining to either long-term monitoring of the repeating FRBs or all-sky surveys with specialized equipments.Therefore,establishing a highly efficient and high quality FRB search pipeline is the primary task in FRB research.Deep learning techniques provide new ideas for FRB search processing.We have detected radio bursts from FRB 20201124A in the L-band observational data of the Nanshan 26 m radio telescope(NSRT-26m)using the constructed deep learning based search pipeline named dispersed dynamic spectra search(DDSS).Afterwards,we further retrained the deep learning model and applied the DDSS framework to S-band observations.In this paper,we present the FRB observation system and search pipeline using the S-band receiver.We carried out search experiments,and successfully detected the radio bursts from the magnetar SGR J1935+2145and FRB 20220912A.The experimental results show that the search pipeline can complete the search efficiently and output the search results with high accuracy.展开更多
The Internet of Things(IoT)has witnessed a significant surge in adoption,particularly through the utilization of Wireless Sensor Networks(WSNs),which comprise small internet-connected devices.These deployments span va...The Internet of Things(IoT)has witnessed a significant surge in adoption,particularly through the utilization of Wireless Sensor Networks(WSNs),which comprise small internet-connected devices.These deployments span various environments and offer a multitude of benefits.However,the widespread use of battery-powered devices introduces challenges due to their limited hardware resources and communication capabilities.In response to this,the Internet Engineering Task Force(IETF)has developed the IPv6 Routing Protocol for Low-power and Lossy Networks(RPL)to address the unique requirements of such networks.Recognizing the critical role of RPL in maintaining high performance,this paper proposes a novel approach to optimizing power consumption.Specifically,it introduces a developed sensor motes topology integrated with a Radio Duty Cycling(RDC)mechanism aimed at minimizing power usage.Through rigorous analysis,the paper evaluates the power efficiency of this approach through several simulations conducted across different network topologies,including random,linear,tree,and elliptical topologies.Additionally,three distinct RDC mechanisms—CXMAC,ContikiMAC,and NullRDC—are investigated to assess their impact on power consumption.The findings of the study,based on a comprehensive and deep analysis of the simulated results,highlight the efficiency of ContikiMAC in power conservation.This research contributes valuable insights into enhancing the energy efficiency of RPL-based IoT networks,ultimately facilitating their widespread deployment and usability in diverse environments.展开更多
In this work,we investigate the covert communication in cognitive radio(CR)networks with the existence of multiple cognitive jammers(CJs).Specifically,the secondary transmitter(ST)helps the primary transmitter(PT)to r...In this work,we investigate the covert communication in cognitive radio(CR)networks with the existence of multiple cognitive jammers(CJs).Specifically,the secondary transmitter(ST)helps the primary transmitter(PT)to relay information to primary receiver(PR),as a reward,the ST can use PT's spectrum to transmit private information against the eavesdropper(Eve)under the help of one selected cognitive jammer(CJ).Meanwhile,we propose three jammer-selection schemes,namely,link-oriented jammer selection(LJS),min-max jammer selection(MMJS)and random jammer selection(RJS).For each scheme,we analyze the average covert throughput(ACT)and covert outage probability(COP).Our simulation results show that CJ is helpful to ST's covert communication,the expected minimum detection error probability and ACT can be significantly improved with the increase of false alarm of CJ.Moreover,the LJS scheme achieves best performance in ACT and COP,followed by RJS scheme,and MMJS scheme shows the worst performance.展开更多
With the development of information technology,more and more devices are connected to the Internet through wireless communication to complete data interconnection.Due to the broadcast characteristics ofwireless channe...With the development of information technology,more and more devices are connected to the Internet through wireless communication to complete data interconnection.Due to the broadcast characteristics ofwireless channels,wireless networks have suffered more and more malicious attacks.Physical layer security has received extensive attention from industry and academia.MIMO is considered to be one of the most important technologies related to physical layer security.Through beamforming technology,messages can be transmitted to legitimate users in an offset direction that is as orthogonal as possible to the interference channel to ensure the reception SINR by legitimate users.Combining the symbiotic radio(SR)technology,this paper considers a symbiotic radio antijamming MIMO system equipped with a multi-antenna system at the main base station.In order to avoid the interference signal and improve the SINR of the signal received by the user.The base station is equipped with a uniform rectangular antenna array,and using Null Space Projection(NSP)Beamforming,Intelligent Reflecting Surface(IRS)can assist in changing the beam’s angle.The simulation results show that NSP Beamforming could make a better use of the null space of interference,which can effectively improve the received SINR of users under directional interference,and improve the utilization efficiency of signal energy.展开更多
Orbital fractures are a frequent and serious problem for practicing ophthalmologists. The complexity of the pathology is explained by the combined nature of the injuries(often associated with craniofacial injuries), m...Orbital fractures are a frequent and serious problem for practicing ophthalmologists. The complexity of the pathology is explained by the combined nature of the injuries(often associated with craniofacial injuries), multistage treatments, results that are often unsatisfactory, and a wide range of complaints about functional and cosmetic limitations. Over the years, significant progress has been made in the field of orbital reconstruction,allowing the transition from traditional methods using simple materials to innovative bioengineering solutions.This evolution has been driven by advances in surgical technologies, imaging techniques, and biomaterials aimed at optimizing the restoration of the shape and function of the orbital region. Traditional approaches are based on the use of autologous tissues such as bone grafts and muscle flaps, which provide biocompatibility and natural integration, but have limitations in terms of customization and accessibility. The advent of patient-specific implants and 3D printing technology has revolutionized the reconstruction of the orbit, allowing implants to be precisely adapted to a patient's anatomy. Biocompatible materials, such as porous polyethylene, titanium, and silicone, have become the basis for orbital reconstruction, ensuring durability and compatibility while minimizing long-term complications. Bioengineered solutions hold promise for further advancements in orbital reconstruction. We searched Pub Med, Cyberleninka, and other verified databases for published articles on orbital reconstruction reported in the literature between 1960 and January 2024. In this article, we consider the advantages and disadvantages of each category of reconstruction materials and provide up-to-date information on the methods for modifying their properties using modern processing technologies.展开更多
The corona discharge from transmission lines in high-altitude areas is more severe than at lower altitudes. The radio interference caused thereby is a key factor to be considered when designing transmission lines. To ...The corona discharge from transmission lines in high-altitude areas is more severe than at lower altitudes. The radio interference caused thereby is a key factor to be considered when designing transmission lines. To study the influence of altitude on negative corona characteristics, an experimental platform comprising a movable small corona cage was established: experiments were conducted at four altitudes in the range of 1120-4320 m, and data on the corona current pulse and radio interference level of 0.8-mm diameter fine copper wire under different negative voltages were collected. The experimental results show that the average amplitude, repetition frequency and average current of the corona current pulse increase with increasing altitude. The dispersion of pulse amplitude increases with increase in altitude, while the randomness of the pulse interval decreases continuously. Taking the average current as an intermediate variable,the relationship between radio interference level and altitude is obtained. The result of this research has some significance for understanding the corona discharge characteristics of ultra-highvoltage lines.展开更多
Introduction: In hyperthyroidism, selective irradiation of the thyroid gland with radioactive iodine is a radical treatment and an alternative to surgery. The aim of this review is to assess the medium-term efficacy o...Introduction: In hyperthyroidism, selective irradiation of the thyroid gland with radioactive iodine is a radical treatment and an alternative to surgery. The aim of this review is to assess the medium-term efficacy of outpatient treatment of hyperthyroidism with iodine-131 in Africa. Methods: We identified the studies carried out in Africa on outpatient radiation therapy between 2016 and 2020. For each article included, we noted the country concerned and the year of publication, the numbers studied, the socio-demographic characteristics of the patients, the indications for radio iodine therapy, the dose administered, the results of the hormonal dosage 6 months after radiation. Results: 13 retrospective studies were included to constitute a total population of 925 patients. The average age was 40.77 years, the sex ratio of 1/5.4 with a clear female predominance. The 3 main etiologies of hyperthyroidism justifying outpatient radio iodine therapy were Graves’ disease (55.89%), toxic multinodular goiter (22.70%) and toxic adenoma (21.40%). The average dose of iodine 131 administered per course is 13.7 mCi. No short-and medium-term complications were reported. The radio iodine therapy was effective in 86.08% (n = 796) of the patients with extremes of 72% and 100%. Conclusion: Radio iodine therapy is effective in Africa. It is simple, inexpensive on an outpatient basis and well tolerated. The introduction of outpatient radio iodine therapy could improve the management of patients with hyperthyroidism in Burkina Faso.展开更多
The Shanghai Tianma 65 m radio telescope(TMRT)is a large,fully rotatable radio telescope with multiple scientific purposes.The main body of the telescope and four low-frequency receiving systems,including L,C,and S/X ...The Shanghai Tianma 65 m radio telescope(TMRT)is a large,fully rotatable radio telescope with multiple scientific purposes.The main body of the telescope and four low-frequency receiving systems,including L,C,and S/X bands,were completed between 2008 and 2012.From 2013 to 2017,four high-frequency receiving systems,including Ku,K,Ka,and Q bands,were constructed and their performance was comprehensively tested.There are three main innovations.(1)A fully movable large radio telescope system with advanced performance and complete functions has been built.(2)An advanced,reliable main reflector adjustment system has been completed,overcoming gravity deformation and creating a large antenna with a main reflective surface accuracy of 0.28 mm(root mean square)for any elevation.(3)Five innovative technologies have been developed to achieve high-precision pointing in any direction within 3″.The TMRT has made a crucial contribution to the orbital measurement and positioning of China’s lunar and deep space probes.Significantly enhancing China's ability to participate in international VLBI observations and radio astronomy,this has facilitated a series of achievements in observational radio astronomical research,in areas such as VLBI,spectral lines,and pulsars.展开更多
Background: The accumulation of free radicals is linked to a number of diseases. Free radicals can be scavenged by antioxidants and reduce their harmful effects. It is therefore essential to look for naturally occurri...Background: The accumulation of free radicals is linked to a number of diseases. Free radicals can be scavenged by antioxidants and reduce their harmful effects. It is therefore essential to look for naturally occurring antioxidants that come from plants, as synthetic antioxidants are toxic, carcinogenic and problematic for the environment. Lycopene is one of the carotenoids, a pigment that dissolves in fat and has antioxidant properties. Materials and Methods: The antioxidant and free radical scavenging activity were assessed using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The impact of lycopene on bacteria (E. coli) susceptibility to γ-radiation was examined by radio sensitivity assay. The study also examined the induction of strand breaks in plasmid pUC19 DNA and how lycopene extract protected the DNA from γ-radiation in vitro. Results: At varying concentrations, lycopene demonstrated its ability to scavenge free radicals such as 2, 2-diphenyl-1-picrylhydrazyl (DPPH). IC<sub>50</sub> for lycopene was determined at 112 μg/mL which was almost partial to IC<sub>50</sub> of standard antioxidant L-ascorbic acid. The D<sub>10</sub> value 180 Gy of E. coli was found to be >2-fold higher in the extract-containing lycopene sample than in the extract-free controls. The lycopene extracts inhibited the radiation-induced deterioration of the plasmid pUC19 DNA. At an IC<sub>50</sub> concentration, lycopene provided the highest level of protection. Conclusion: Lycopene functions as an efficient free radical scavenger and possible natural antioxidant source. For cancer patients and others who frequently expose themselves to radiation, lycopene may be a useful plant-based pharmaceutical product for treating a variety of diseases caused by free radicals.展开更多
Radioheliographs can obtain solar images at high temporal and spatial resolution,with a high dynamic range.These are among the most important instruments for studying solar radio bursts,understanding solar eruption ev...Radioheliographs can obtain solar images at high temporal and spatial resolution,with a high dynamic range.These are among the most important instruments for studying solar radio bursts,understanding solar eruption events,and conducting space weather forecasting.This study aims to explore the effective use of radioheliographs for solar observations,specifically for imaging coronal mass ejections(CME),to track their evolution and provide space weather warnings.We have developed an imaging simulation program based on the principle of aperture synthesis imaging,covering the entire data processing flow from antenna configuration to dirty map generation.For grid processing,we propose an improved non-uniform fast Fourier transform(NUFFT)method to provide superior image quality.Using simulated imaging of radio coronal mass ejections,we provide practical recommendations for the performance of radioheliographs.This study provides important support for the validation and calibration of radioheliograph data processing,and is expected to profoundly enhance our understanding of solar activities.展开更多
Due to a series of challenges such as low-orbit maintenance of satellites, the air-breathing electric propulsion has got widespread attention. Commonly, the radio frequency ion thruster is favored by low-orbit mission...Due to a series of challenges such as low-orbit maintenance of satellites, the air-breathing electric propulsion has got widespread attention. Commonly, the radio frequency ion thruster is favored by low-orbit missions due to its high specific impulse and efficiency. In this paper, the power transfer efficiency of the radio frequency ion thruster with different gas compositions is studied experimentally, which is obtained by measuring the radio frequency power and current of the antenna coil with and without discharge operation. The results show that increasing the turns of antenna coils can effectively improve the radio frequency power transfer efficiency, which is due to the improvement of Q factor. In pure N_2 discharge,with the increase of radio frequency power, the radio frequency power transfer efficiency first rises rapidly and then exhibits a less steep increasing trend. The radio frequency power transfer efficiency increases with the increase of gas pressure at relatively high power, while declines rapidly at relatively low power. In N_(2)/O_(2) discharge, increasing the N_(2) content at high power can improve the radio frequency power transfer efficiency, but the opposite was observed at low power. In order to give a better understanding of these trends, an analytic solution in limit cases is utilized, and a Langmuir probe was employed to measure the electron density. It is found that the evolution of radio frequency power transfer efficiency can be well explained by the variation of plasma resistance, which is related to the electron density and the effective electron collision frequency.展开更多
The surface accuracy of a radio telescope is directly related to its operational efficiency and detection sensitivity.This is crucial under high-frequency observation conditions,where surface shape errors need to be c...The surface accuracy of a radio telescope is directly related to its operational efficiency and detection sensitivity.This is crucial under high-frequency observation conditions,where surface shape errors need to be controlled to within 1/16 of the working wavelength.In addition,the primary reflector of large radio telescopes is subject to dynamic deformation,caused by factors such as gravity and thermal effects.This paper presents a method for detecting the surface shape of radio telescopes using radio interferometry techniques combined with active reflector adjustment technology.This enables accurate assessment and correction of surface errors,ensuring the electrical performance of the radio telescope.This study investigates the practical applications of high-precision measurement techniques,such as microwave holography,out-of-focus holography,and wavefront distortion methods at the Tianma 65 m radio telescope(TMRT).Furthermore,the study presents the construction method of gravity models at different elevation angles and demonstrates the efficacy of the active reflector model.The results of the measurements indicate that the application of these methods to the TMRT has led to a notable enhancement of the accuracy of the primary reflector and a substantial improvement in efficiency in the Q-band.Through a process of iterative measurements and adjustments,the surface shape error is ultimately reduced to 0.28 mm root mean square(RMS).展开更多
基金Guangdong Province Undergraduate Online Open Course Guidance Committee Research Project(2022ZXKC462)Foshan Philosophy and Social Science Planning Project(2024-GJ 037)+4 种基金Provincial First-Class Undergraduate Courses of Guangdong Provincial Education Department(Guangdong Education Gaohan[2022]No.10)Innovation Project of Guangdong Graduate Education(2022JGXM129,2022JGXM128,2023ANLK-080)Foshan University Curriculum Ideological and Political Teaching Reform and Practice Demonstration Project in 2023Quality Engineering Project of Foshan University in 2023Collaborative Education Project of the Ministry of Education in 2023(230703232312141)。
文摘In the context of emerging engineering disciplines,a hybrid teaching reform for the Bioengineering Downstream Technology course,based on ideological and political education and online open courses,is being carried out.This reform focuses on aspects such as“building a professional teacher team for ideological and political education,scientifically designing the ideological and political teaching system,innovating classroom teaching methods,and improving both formative and summative evaluation systems.”The“Craftsmanship in Education and Cultivating Soul and Roots”small private online course hybrid teaching reform for the Bioengineering Downstream Technology online open course provides a replicable model for the comprehensive implementation of ideological and political education in engineering courses and offers a reference for advancing ideological and political education and hybrid teaching reform in new engineering disciplines.
基金supported by The Plastic Surgery Foundation Research Pilot Grant,No.627383(to KAS).
文摘Peripheral nerve injuries remain a challenging problem in need of better treatment strategies.Despite best efforts at surgical reconstruction and postoperative rehabilitation,patients are often left with persistent,debilitating motor and sensory deficits.There are currently no therapeutic strategies proven to enhance the regenerative process in humans.A clinical need exists for the development of technologies to promote nerve regeneration and improve functional outcomes.Recent advances in the fields of tissue engineering and nanotechnology have enabled biomaterial scaffolds to modulate the host response to tissue repair through tailored mechanical,chemical,and conductive cues.New bioengineered approaches have enabled targeted,sustained delivery of protein therapeutics with the capacity to unlock the clinical potential of a myriad of neurotrophic growth factors that have demonstrated promise in enhancing regenerative outcomes.As such,further exploration of combinatory strategies leveraging these technological advances may offer a pathway towards clinically translatable solutions to advance the care of patients with peripheral nerve injuries.This review first presents the various emerging bioengineering strategies that can be applied for the management of nerve gap injuries.We cover the rationale and limitations for their use as an alternative to autografts,focusing on the approaches to increase the number of regenerating axons crossing the repair site,and facilitating their growth towards the distal stump.We also discuss the emerging growth factor-based therapeutic strategies designed to improve functional outcomes in a multimodal fashion,by accelerating axonal growth,improving the distal regenerative environment,and preventing end-organs atrophy.
文摘Liver transplantation is the only curative therapy for end stage liver disease,but is limited by the organ shortage,and is associated with the adverse consequences of immunosuppression.Repopulation of decellularised whole organ scaffolds with appropriate cells of recipient origin offers a theoretically attractive solution,allowing reliable and timely organ sourcing without the need for immunosuppression.Decellularisation methodologies vary widely but seek to address the conflicting objectives of removing the cellular component of tissues whilst keeping the 3D structure of the extra-cellular matrix intact,as well as retaining the instructive cell fate determining biochemicals contained therein.Liver scaffold recellularisation has progressed from small rodent in vitro studies to large animal in vivo perfusion models,using a wide range of cell types including primary cells,cell lines,foetal stem cells,and induced pluripotent stem cells.Within these models,a limited but measurable degree of physiologically significant hepatocyte function has been reported with demonstrable ammonia metabolism in vivo.Biliary repopulation and function have been restricted by challenges relating to the culture and propagations of cholangiocytes,though advances in organoid culture may help address this.Hepatic vasculature repopulation has enabled sustainable blood perfusion in vivo,but with cell types that would limit clinical applications,and which have not been shown to have the specific functions of liver sinusoidal endothelial cells.Minority cell groups such as Kupffer cells and stellate cells have not been repopulated.Bioengineering by repopulation of decellularised scaffolds has significantly progressed,but there remain significant experimental challenges to be addressed before therapeutic applications may be envisaged.
文摘The Tianma 65 m radio telescope(TMRT)at Shanghai is a fully steerable single-dish radio telescope in China,operating at centimeter to millimeter wavelengths(1.25 GHz to 50 GHz).This paper presents details on the main specifications,design,performance analysis,testing,and construction of the telescope antenna.The measured total efficiency is better than 50%over the whole elevation angle range,first sidelobe levels are less than−20 dB,antenna system noise temperatures are less than 70 K at 30°elevation angle,and pointing accuracy is less than 3″.The measured and calculated results are in good agreement,verifying the effectiveness of the design and analysis.
基金National Natural Science Foundation of China under Grant No.61973037China Postdoctoral Science Foundation 2022M720419 to provide fund for conducting experiments。
文摘The identification of intercepted radio fuze modulation types is a prerequisite for decision-making in interference systems.However,the electromagnetic environment of modern battlefields is complex,and the signal-to-noise ratio(SNR)of such environments is usually low,which makes it difficult to implement accurate recognition of radio fuzes.To solve the above problem,a radio fuze automatic modulation recognition(AMR)method for low-SNR environments is proposed.First,an adaptive denoising algorithm based on data rearrangement and the two-dimensional(2D)fast Fourier transform(FFT)(DR2D)is used to reduce the noise of the intercepted radio fuze intermediate frequency(IF)signal.Then,the textural features of the denoised IF signal rearranged data matrix are extracted from the statistical indicator vectors of gray-level cooccurrence matrices(GLCMs),and support vector machines(SVMs)are used for classification.The DR2D-based adaptive denoising algorithm achieves an average correlation coefficient of more than 0.76 for ten fuze types under SNRs of-10 d B and above,which is higher than that of other typical algorithms.The trained SVM classification model achieves an average recognition accuracy of more than 96%on seven modulation types and recognition accuracies of more than 94%on each modulation type under SNRs of-12 d B and above,which represents a good AMR performance of radio fuzes under low SNRs.
文摘Mainstream media play a crucial role in constructing the cultural memory of a city.This study used 319 short videos released by“Hi Chengdu,”a new media product of Chengdu Radio and Television,as samples.Based on the grounded theory,a research framework encompassing“content,technology,and discourse”was established to explore the paths through which mainstream media construct the cultural memory.Regarding content,this paper emphasized temporal and spatial contexts and urban spaces,delving deep into the themes of the cultural memory and vehicles for it.In terms of technology,this paper discussed the practice of leveraging audio/visual-mode discourse to stitch together the impressions of a city and evoke emotional resonance to create a“flow”of memory.As for discourse,this paper looked at the performance of a communication ritual to frame concepts and shape urban identity.It is essential to break free from conventional thinking and leverage local culture as the primary driving force to further boost a city’s productivity,in order to excel in cultural communication.
基金supported by the National SKA Program of China(2022SKA0120101,2022SKA0130100,2022SKA 0130104)the National Natural Science Foundation of China(NSFC,grant No.12103013)+5 种基金the Foundation of Science and Technology of Guizhou Province(Nos.(2021)023)the Foundation of Guizhou Provincial Education Department(Nos.KY(2021)303,KY(2020)003,KY(2023)059)supported by the National Natural Science Foundation of China(NSFC,grant Nos.12103076 and 12233005)the National Key R&D Program of China(2020YFE0202100)the Shanghai Sailing Program(21YF1455300)the China Postdoctoral Science Foundation(2021M693267)。
文摘We present an independent catalog(FRIIRGcat)of 45,241 Fanaroff–Riley TypeⅡ(FR-Ⅱ)radio galaxies compiled from the Very Large Array Faint Images of the Radio Sky at Twenty-centimeters(FIRST)survey and employed the deep learning method.Among them,optical and/or infrared counterparts are identified for 41,425 FR-Ⅱs.This catalog spans luminosities 2.63×10^(22)≤L_(rad)≤6.76×10^(29)W Hz^(-1)and redshifts up to z=5.01.The spectroscopic classification indicates that there are 1431 low-excitation radio galaxies and 260 high-excitation radio galaxies.Among the spectroscopically identified sources,black hole masses are estimated for 4837 FR-Is,which are in 10^(7.5)■M_(BH)■10^(9.5)M_(⊙).Interestingly,this catalog reveals a couple of giant radio galaxies(GRGs),which are already in the existing GRG catalog,confirming the efficiency of this FR-I catalog.Furthermore,284new GRGs are unveiled in this new FR-I sample;they have the largest projected sizes ranging from 701 to1209 kpc and are located at redshifts 0.31<z<2.42.Finally,we explore the distribution of the jet position angle and it shows that the faint Images of the FIRST images are significantly affected by the systematic effect(the observing beams).The method presented in this work is expected to be applicable to the radio sky surveys that are currently being conducted because they have finely refined telescope arrays.On the other hand,we are expecting that further new methods will be dedicated to solving this problem.
基金supported by the Chinese Academy of Sciences(CAS)“Light of West China”Program(No.2022-XBQNXZ-015)the National Natural Science Foundation of China(NSFC,grant No.11903071)the Operation,Maintenance and Upgrading Fund for Astronomical Telescopes and Facility Instruments,budgeted from the Ministry of Finance(MOF)of China and administered by the Chinese Academy of Sciences(CAS)。
文摘Fast radio bursts(FRBs)are among the most studied radio transients in astrophysics,but their origin and radiation mechanism are still unknown.It is a challenge to search for FRB events in a huge amount of observational data with high speed and high accuracy.With the rapid advancement of the FRB research process,FRB searching has changed from archive data mining to either long-term monitoring of the repeating FRBs or all-sky surveys with specialized equipments.Therefore,establishing a highly efficient and high quality FRB search pipeline is the primary task in FRB research.Deep learning techniques provide new ideas for FRB search processing.We have detected radio bursts from FRB 20201124A in the L-band observational data of the Nanshan 26 m radio telescope(NSRT-26m)using the constructed deep learning based search pipeline named dispersed dynamic spectra search(DDSS).Afterwards,we further retrained the deep learning model and applied the DDSS framework to S-band observations.In this paper,we present the FRB observation system and search pipeline using the S-band receiver.We carried out search experiments,and successfully detected the radio bursts from the magnetar SGR J1935+2145and FRB 20220912A.The experimental results show that the search pipeline can complete the search efficiently and output the search results with high accuracy.
文摘The Internet of Things(IoT)has witnessed a significant surge in adoption,particularly through the utilization of Wireless Sensor Networks(WSNs),which comprise small internet-connected devices.These deployments span various environments and offer a multitude of benefits.However,the widespread use of battery-powered devices introduces challenges due to their limited hardware resources and communication capabilities.In response to this,the Internet Engineering Task Force(IETF)has developed the IPv6 Routing Protocol for Low-power and Lossy Networks(RPL)to address the unique requirements of such networks.Recognizing the critical role of RPL in maintaining high performance,this paper proposes a novel approach to optimizing power consumption.Specifically,it introduces a developed sensor motes topology integrated with a Radio Duty Cycling(RDC)mechanism aimed at minimizing power usage.Through rigorous analysis,the paper evaluates the power efficiency of this approach through several simulations conducted across different network topologies,including random,linear,tree,and elliptical topologies.Additionally,three distinct RDC mechanisms—CXMAC,ContikiMAC,and NullRDC—are investigated to assess their impact on power consumption.The findings of the study,based on a comprehensive and deep analysis of the simulated results,highlight the efficiency of ContikiMAC in power conservation.This research contributes valuable insights into enhancing the energy efficiency of RPL-based IoT networks,ultimately facilitating their widespread deployment and usability in diverse environments.
基金supported in part by the National Natural Science Foundation of China(No.61941105,No.61901327 and No.62101450)in part by the National Natural Science Foundation for Distinguished Young Scholar(No.61825104)+1 种基金in part by the Fundamental Research Funds for the Central Universities(JB210109)in part by the Foundation of State Key Laboratory of Integrated Services Networks of Xidian University(ISN22-03)。
文摘In this work,we investigate the covert communication in cognitive radio(CR)networks with the existence of multiple cognitive jammers(CJs).Specifically,the secondary transmitter(ST)helps the primary transmitter(PT)to relay information to primary receiver(PR),as a reward,the ST can use PT's spectrum to transmit private information against the eavesdropper(Eve)under the help of one selected cognitive jammer(CJ).Meanwhile,we propose three jammer-selection schemes,namely,link-oriented jammer selection(LJS),min-max jammer selection(MMJS)and random jammer selection(RJS).For each scheme,we analyze the average covert throughput(ACT)and covert outage probability(COP).Our simulation results show that CJ is helpful to ST's covert communication,the expected minimum detection error probability and ACT can be significantly improved with the increase of false alarm of CJ.Moreover,the LJS scheme achieves best performance in ACT and COP,followed by RJS scheme,and MMJS scheme shows the worst performance.
基金This work was supported by the National Natural Science Foundation of China(62271192)Henan Provincial Scientists Studio(GZS2022015),Central Plains Talents Plan(ZYYCYU202012173)+8 种基金National Key R&D Program of China(2020YFB2008400)the Program of CEMEE(2022Z00202B)LAGEO of Chinese Academy of Sciences(LAGEO-2019-2)Program for Science&Technology Innovation Talents in the University of Henan Province(20HASTIT022)Natural Science Foundation of Henan under Grant 202300410126Program for Innovative Research Team in University of Henan Province(21IRTSTHN015)Equipment Pre-Research Joint Research Program of Ministry of Education(8091B032129)Training Program for Young Scholar of Henan Province forColleges andUniversities(2020GGJS172)Programfor Science&Technology Innovation Talents in Universities of Henan Province under Grand(22HASTIT020)and Henan Province Science Fund for Distinguished Young Scholars(222300420006).
文摘With the development of information technology,more and more devices are connected to the Internet through wireless communication to complete data interconnection.Due to the broadcast characteristics ofwireless channels,wireless networks have suffered more and more malicious attacks.Physical layer security has received extensive attention from industry and academia.MIMO is considered to be one of the most important technologies related to physical layer security.Through beamforming technology,messages can be transmitted to legitimate users in an offset direction that is as orthogonal as possible to the interference channel to ensure the reception SINR by legitimate users.Combining the symbiotic radio(SR)technology,this paper considers a symbiotic radio antijamming MIMO system equipped with a multi-antenna system at the main base station.In order to avoid the interference signal and improve the SINR of the signal received by the user.The base station is equipped with a uniform rectangular antenna array,and using Null Space Projection(NSP)Beamforming,Intelligent Reflecting Surface(IRS)can assist in changing the beam’s angle.The simulation results show that NSP Beamforming could make a better use of the null space of interference,which can effectively improve the received SINR of users under directional interference,and improve the utilization efficiency of signal energy.
文摘Orbital fractures are a frequent and serious problem for practicing ophthalmologists. The complexity of the pathology is explained by the combined nature of the injuries(often associated with craniofacial injuries), multistage treatments, results that are often unsatisfactory, and a wide range of complaints about functional and cosmetic limitations. Over the years, significant progress has been made in the field of orbital reconstruction,allowing the transition from traditional methods using simple materials to innovative bioengineering solutions.This evolution has been driven by advances in surgical technologies, imaging techniques, and biomaterials aimed at optimizing the restoration of the shape and function of the orbital region. Traditional approaches are based on the use of autologous tissues such as bone grafts and muscle flaps, which provide biocompatibility and natural integration, but have limitations in terms of customization and accessibility. The advent of patient-specific implants and 3D printing technology has revolutionized the reconstruction of the orbit, allowing implants to be precisely adapted to a patient's anatomy. Biocompatible materials, such as porous polyethylene, titanium, and silicone, have become the basis for orbital reconstruction, ensuring durability and compatibility while minimizing long-term complications. Bioengineered solutions hold promise for further advancements in orbital reconstruction. We searched Pub Med, Cyberleninka, and other verified databases for published articles on orbital reconstruction reported in the literature between 1960 and January 2024. In this article, we consider the advantages and disadvantages of each category of reconstruction materials and provide up-to-date information on the methods for modifying their properties using modern processing technologies.
基金supported by the Science and Technology Project of State Grid Corporation of China (No.5200202155587A-0-5-GC)。
文摘The corona discharge from transmission lines in high-altitude areas is more severe than at lower altitudes. The radio interference caused thereby is a key factor to be considered when designing transmission lines. To study the influence of altitude on negative corona characteristics, an experimental platform comprising a movable small corona cage was established: experiments were conducted at four altitudes in the range of 1120-4320 m, and data on the corona current pulse and radio interference level of 0.8-mm diameter fine copper wire under different negative voltages were collected. The experimental results show that the average amplitude, repetition frequency and average current of the corona current pulse increase with increasing altitude. The dispersion of pulse amplitude increases with increase in altitude, while the randomness of the pulse interval decreases continuously. Taking the average current as an intermediate variable,the relationship between radio interference level and altitude is obtained. The result of this research has some significance for understanding the corona discharge characteristics of ultra-highvoltage lines.
文摘Introduction: In hyperthyroidism, selective irradiation of the thyroid gland with radioactive iodine is a radical treatment and an alternative to surgery. The aim of this review is to assess the medium-term efficacy of outpatient treatment of hyperthyroidism with iodine-131 in Africa. Methods: We identified the studies carried out in Africa on outpatient radiation therapy between 2016 and 2020. For each article included, we noted the country concerned and the year of publication, the numbers studied, the socio-demographic characteristics of the patients, the indications for radio iodine therapy, the dose administered, the results of the hormonal dosage 6 months after radiation. Results: 13 retrospective studies were included to constitute a total population of 925 patients. The average age was 40.77 years, the sex ratio of 1/5.4 with a clear female predominance. The 3 main etiologies of hyperthyroidism justifying outpatient radio iodine therapy were Graves’ disease (55.89%), toxic multinodular goiter (22.70%) and toxic adenoma (21.40%). The average dose of iodine 131 administered per course is 13.7 mCi. No short-and medium-term complications were reported. The radio iodine therapy was effective in 86.08% (n = 796) of the patients with extremes of 72% and 100%. Conclusion: Radio iodine therapy is effective in Africa. It is simple, inexpensive on an outpatient basis and well tolerated. The introduction of outpatient radio iodine therapy could improve the management of patients with hyperthyroidism in Burkina Faso.
基金supported by National Natural Science Foundation of China(12273098).
文摘The Shanghai Tianma 65 m radio telescope(TMRT)is a large,fully rotatable radio telescope with multiple scientific purposes.The main body of the telescope and four low-frequency receiving systems,including L,C,and S/X bands,were completed between 2008 and 2012.From 2013 to 2017,four high-frequency receiving systems,including Ku,K,Ka,and Q bands,were constructed and their performance was comprehensively tested.There are three main innovations.(1)A fully movable large radio telescope system with advanced performance and complete functions has been built.(2)An advanced,reliable main reflector adjustment system has been completed,overcoming gravity deformation and creating a large antenna with a main reflective surface accuracy of 0.28 mm(root mean square)for any elevation.(3)Five innovative technologies have been developed to achieve high-precision pointing in any direction within 3″.The TMRT has made a crucial contribution to the orbital measurement and positioning of China’s lunar and deep space probes.Significantly enhancing China's ability to participate in international VLBI observations and radio astronomy,this has facilitated a series of achievements in observational radio astronomical research,in areas such as VLBI,spectral lines,and pulsars.
文摘Background: The accumulation of free radicals is linked to a number of diseases. Free radicals can be scavenged by antioxidants and reduce their harmful effects. It is therefore essential to look for naturally occurring antioxidants that come from plants, as synthetic antioxidants are toxic, carcinogenic and problematic for the environment. Lycopene is one of the carotenoids, a pigment that dissolves in fat and has antioxidant properties. Materials and Methods: The antioxidant and free radical scavenging activity were assessed using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The impact of lycopene on bacteria (E. coli) susceptibility to γ-radiation was examined by radio sensitivity assay. The study also examined the induction of strand breaks in plasmid pUC19 DNA and how lycopene extract protected the DNA from γ-radiation in vitro. Results: At varying concentrations, lycopene demonstrated its ability to scavenge free radicals such as 2, 2-diphenyl-1-picrylhydrazyl (DPPH). IC<sub>50</sub> for lycopene was determined at 112 μg/mL which was almost partial to IC<sub>50</sub> of standard antioxidant L-ascorbic acid. The D<sub>10</sub> value 180 Gy of E. coli was found to be >2-fold higher in the extract-containing lycopene sample than in the extract-free controls. The lycopene extracts inhibited the radiation-induced deterioration of the plasmid pUC19 DNA. At an IC<sub>50</sub> concentration, lycopene provided the highest level of protection. Conclusion: Lycopene functions as an efficient free radical scavenger and possible natural antioxidant source. For cancer patients and others who frequently expose themselves to radiation, lycopene may be a useful plant-based pharmaceutical product for treating a variety of diseases caused by free radicals.
基金supported by the grants of National Natural Science Foundation of China(42374219,42127804)the Qilu Young Researcher Project of Shandong University.
文摘Radioheliographs can obtain solar images at high temporal and spatial resolution,with a high dynamic range.These are among the most important instruments for studying solar radio bursts,understanding solar eruption events,and conducting space weather forecasting.This study aims to explore the effective use of radioheliographs for solar observations,specifically for imaging coronal mass ejections(CME),to track their evolution and provide space weather warnings.We have developed an imaging simulation program based on the principle of aperture synthesis imaging,covering the entire data processing flow from antenna configuration to dirty map generation.For grid processing,we propose an improved non-uniform fast Fourier transform(NUFFT)method to provide superior image quality.Using simulated imaging of radio coronal mass ejections,we provide practical recommendations for the performance of radioheliographs.This study provides important support for the validation and calibration of radioheliograph data processing,and is expected to profoundly enhance our understanding of solar activities.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12005031 and 12275041)the Natural Science Fund from the Interdisciplinary Project of Dalian University(Grant No.DLUXK-2023-QN-001)。
文摘Due to a series of challenges such as low-orbit maintenance of satellites, the air-breathing electric propulsion has got widespread attention. Commonly, the radio frequency ion thruster is favored by low-orbit missions due to its high specific impulse and efficiency. In this paper, the power transfer efficiency of the radio frequency ion thruster with different gas compositions is studied experimentally, which is obtained by measuring the radio frequency power and current of the antenna coil with and without discharge operation. The results show that increasing the turns of antenna coils can effectively improve the radio frequency power transfer efficiency, which is due to the improvement of Q factor. In pure N_2 discharge,with the increase of radio frequency power, the radio frequency power transfer efficiency first rises rapidly and then exhibits a less steep increasing trend. The radio frequency power transfer efficiency increases with the increase of gas pressure at relatively high power, while declines rapidly at relatively low power. In N_(2)/O_(2) discharge, increasing the N_(2) content at high power can improve the radio frequency power transfer efficiency, but the opposite was observed at low power. In order to give a better understanding of these trends, an analytic solution in limit cases is utilized, and a Langmuir probe was employed to measure the electron density. It is found that the evolution of radio frequency power transfer efficiency can be well explained by the variation of plasma resistance, which is related to the electron density and the effective electron collision frequency.
基金supported by the National Key R&D Program of China(2018YFA0404702,2019YFA0708904,2021YFC2203501)Shanghai Key Laboratory of Space Navigation and Positioning Techniques,the National Natural Science Foundation of China(12273097,11903068).
文摘The surface accuracy of a radio telescope is directly related to its operational efficiency and detection sensitivity.This is crucial under high-frequency observation conditions,where surface shape errors need to be controlled to within 1/16 of the working wavelength.In addition,the primary reflector of large radio telescopes is subject to dynamic deformation,caused by factors such as gravity and thermal effects.This paper presents a method for detecting the surface shape of radio telescopes using radio interferometry techniques combined with active reflector adjustment technology.This enables accurate assessment and correction of surface errors,ensuring the electrical performance of the radio telescope.This study investigates the practical applications of high-precision measurement techniques,such as microwave holography,out-of-focus holography,and wavefront distortion methods at the Tianma 65 m radio telescope(TMRT).Furthermore,the study presents the construction method of gravity models at different elevation angles and demonstrates the efficacy of the active reflector model.The results of the measurements indicate that the application of these methods to the TMRT has led to a notable enhancement of the accuracy of the primary reflector and a substantial improvement in efficiency in the Q-band.Through a process of iterative measurements and adjustments,the surface shape error is ultimately reduced to 0.28 mm root mean square(RMS).