Genetic load and inbreeding are recognized as important factors to be considered in conservation programs.Elevated levels of both can increase the risk of population extinction by negatively impacting fitness-related ...Genetic load and inbreeding are recognized as important factors to be considered in conservation programs.Elevated levels of both can increase the risk of population extinction by negatively impacting fitness-related characters in many species of plants and animals,including humans(inbreeding depression).Genomic tech-niques are increasingly used in measuring and understanding genetic load and inbreeding and their importance in evolution and conservation.We used whole genome resequencing data from two sibling grouse species in subarctic Eurasia to quantify both.We found a large range of inbreeding measured as FROH(fraction of runs of homozygosity)in individuals from different populations of Chinese Grouse(Tetrastes sewerzowi)and Hazel Grouse(T.bonasia).FROH estimated from genome-wide runs of homozygosity(ROH)ranged from 0.02 to 0.24 among Chinese Grouse populations and from 0.01 to 0.44 in Hazel Grouse.Individuals from a population of Chinese Grouse residing in the Qilian mountains and from the European populations of Hazel Grouse(including samples from Sweden,Germany and Northeast Poland)were the most inbred(FROH ranged from 0.10 to 0.23 and 0.11 to 0.44,respectively).These levels are comparable to other highly inbred populations of birds.Hazel Grouse from northern China and Chinese Grouse residing in the Qinghai-Tibetan Plateau showed relatively lower inbreeding levels.Comparisons of the ratio between deleterious missense mutations and synonymous mutations revealed higher levels in Chinese Grouse as compared to Hazel Grouse.These results are possibly explained by higher fixation rates,mutational melt down,in the range-restricted Chinese Grouse compared to the wide-ranging Hazel Grouse.However,when we compared the relatively more severe class of loss-of-function muta-tions,Hazel Grouse had slightly higher levels than Chinese Grouse,a result which may indicate that purifying selection(purging)has been more efficient in Chinese Grouse on this class of mutations.展开更多
Automated optical inspection(AOI)is a significant process in printed circuit board assembly(PCBA)production lines which aims to detect tiny defects in PCBAs.Existing AOI equipment has several deficiencies including lo...Automated optical inspection(AOI)is a significant process in printed circuit board assembly(PCBA)production lines which aims to detect tiny defects in PCBAs.Existing AOI equipment has several deficiencies including low throughput,large computation cost,high latency,and poor flexibility,which limits the efficiency of online PCBA inspection.In this paper,a novel PCBA defect detection method based on a lightweight deep convolution neural network is proposed.In this method,the semantic segmentation model is combined with a rule-based defect recognition algorithm to build up a defect detection frame-work.To improve the performance of the model,extensive real PCBA images are collected from production lines as datasets.Some optimization methods have been applied in the model according to production demand and enable integration in lightweight computing devices.Experiment results show that the production line using our method realizes a throughput more than three times higher than traditional methods.Our method can be integrated into a lightweight inference system and pro-mote the flexibility of AOI.The proposed method builds up a general paradigm and excellent example for model design and optimization oriented towards industrial requirements.展开更多
For migratory waterbirds,the quality of wintering habitat is related to spring migration and successful breeding in the next year.The availability of food resources in the habitat is critical and varies within water l...For migratory waterbirds,the quality of wintering habitat is related to spring migration and successful breeding in the next year.The availability of food resources in the habitat is critical and varies within water levels.Although the water-level fluctuations in Poyang Lake have been extremely variable interannually in recent years,the wintering waterbird populations have remained relatively stable.Hence,the mechanism of maintaining the stability is worth exploring.This study aimed to compare the distribution of vegetation and herbivorous wa-terbirds in 2015-2016 and 2016-2017,focusing on three shallow sub-lakes and one main lake are.The results showed that the emergence of tubers and the growth of Carex spp.provided a continuous food supply and habitat for wintering waterbirds with a gradual decline in the water level.Shallow sub-lakes supported almost all of the tuber-eating waterbirds(1.42-1.62×10^(5))and most geese(1.34-1.53×10^(6)).However,the main lake area,covered with Persicaria hydropiper,did not provide adequate and accessible food.This resulted in almost no distribution of tuber-eating waterbirds,with only a few geese congregating in early winter.Our results demonstrated that the shallow sub-lakes under human control provided a different environment from the main lake and are key to sustaining the successful wintering of hundreds of thousands of migratory waterbirds in Poyang Lake.Therefore,we recommend refining the anthropogenic management of the shallow sub-lakes to regulate the water level to ensure the carrying capacity of Poyang Lake.展开更多
Migration of vascular smooth muscle cells (VSMCs) from the media to intima constitutes a critical step in the development of proliferative vascular diseases. To elucidate the regulatory mechanism of VSMCs motility, th...Migration of vascular smooth muscle cells (VSMCs) from the media to intima constitutes a critical step in the development of proliferative vascular diseases. To elucidate the regulatory mechanism of VSMCs motility, the roles of caldesmon (CaD) were investigated previously. CaD is an actin-binding protein dynamically regulating cytoskeleton structure. In this study, the potential role of CaD in mediating proliferation and motility of VSMCs were discussed. First, structural effect of CaD on cytoskeleton integrity was analyzed with CaD knock-down;second, the proliferation of VSMCs was measured in CaD knock-down and control cells;third, the specific role of CaD on VSMCs motilities was evaluated with in vitro migration and invasion assays. We found that CaD is an integral component to maintain cytoskeleton integrity of VSMCs. Our data indicated that CaD suppression does not show significant influence on VSMCs proliferation, but negatively modulates the motilities of VSMCs, and CaD depletion would significantly facilitate migration and invasion of VSMCs.展开更多
The course ROS Robot Programming Practice is designed to equip students with both the foundational principles and practical applications of the Robot Operating System(ROS)through structured instruction and hands-on ex...The course ROS Robot Programming Practice is designed to equip students with both the foundational principles and practical applications of the Robot Operating System(ROS)through structured instruction and hands-on exercises.This paper summarizes the course’s pedagogical approach and the insights gained from its implementation,focusing on key areas such as the practical teaching platform,instructional system,teaching methods,and evaluation mechanisms.The practical teaching platform incorporates robotic arms and mobile robots,along with commonly used sensors,to engage students and stimulate their interest in robotics.A well-structured teaching system is employed,guiding students through a series of experiments-ranging from basic tasks to modeling and simulation experiments,sensor experiments,mobile robot tasks,robotic arm exercises,and comprehensive project practices.Regarding teaching methods,a blended learning approach and progressive instructional model are utilized to ensure active student participation.This approach follows a logical progression,starting with fundamental ROS knowledge,advancing to robot applications,and culminating in comprehensive project-based practice.In terms of evaluation,a dual approach combining process and outcome assessments is employed,ensuring that students’performance is evaluated comprehensively through various metrics.展开更多
Heat shock protein 47 (HSP47) is a collagen-specific molecular chaperone that is required for mo-lecular maturation of various types of collagens. Many studies have shown a close association be-tween increased express...Heat shock protein 47 (HSP47) is a collagen-specific molecular chaperone that is required for mo-lecular maturation of various types of collagens. Many studies have shown a close association be-tween increased expression of HSP47 and excessive accumulation of collagens in scar tissues of various human fibrotic diseases. However, the role of HSP47 in formation of scar after glaucoma filtration surgery is still unclear. In this study, we deleted the expression of HSP47 in human tent on fibroblasts (HTFs) by virus infection, and then the proliferation and collagen synthesis were compared between HSP47 deletion cells and control upon TGF-β1 stimulation. Our data showed that HSP47 deletion could significantly inhibit the proliferation and collagen synthesis of HTFs upon TGF-β1 stimulation, HSP47 gene suppression might be a novel method to against the formation of scar after glaucoma surgery.展开更多
Aprotic lithium–oxygen batteries(LOBs)have been recognized as novel energy storage devices for their outstanding specific energy density,while the large discharge/charge overpotential is a tough barrier to be overcom...Aprotic lithium–oxygen batteries(LOBs)have been recognized as novel energy storage devices for their outstanding specific energy density,while the large discharge/charge overpotential is a tough barrier to be overcome.Here,hetero-structured MoS_(2)/ZnIn_(2)S_(4) nanosheets have been prepared to capture visible light and the generated charge carriers are utilized for promoting both the oxygen reduction reaction and the oxygen evolution reaction.With the light illumination in the discharge process,the abundant photo-inspired electrons serve as the reaction sites to promote the reduction of O_(2) into LiO_(2) which is finally deposited as Li_(2)O_(2).On the contrary,the generated holes in the valence band can contribute to the low oxidization potential of Li_(2)O_(2) during the charge process.It delivers a low charge potential of 3.29 V,with an excellent resulting energy efficiency of 96.7%,much superior to that of 69.2%in the dark condition.It is noted that the involvement of photoelectrons has influenced the growth of Li_(2)O_(2) films on the MoS_(2)/ZnIn_(2)S_(4) nanosheets through the surface-adsorption pathway.The insights from the theoretical calculation confirm that the photoelectrons favor the absorption of LiO_(2) and the formation of the Li_(2)O_(2) film through the surface route.Therefore,this paper provides a deeper understanding of the mechanism of photoinspired charge carriers in LOBs and will enable further exploration of photo-involved energy storage systems.展开更多
Very-high-frequency(VHF)gun photoinjectors,capable of producing high-brightness and high-repetitionrate electron bunches,are some of the best electron sources for driving MHz-class repetition-rate free-electron lasers...Very-high-frequency(VHF)gun photoinjectors,capable of producing high-brightness and high-repetitionrate electron bunches,are some of the best electron sources for driving MHz-class repetition-rate free-electron lasers.In this study,the beam dynamics optimization of a VHF gun photoinjector for Shanghai HIgh Repetition Rate X-ray Free Electron Laser and Extreme Light Facility(SHINE)is systematically demonstrated using a genetic algorithm.Through the inclusion of the solenoid geometry as an optimization variable into the genetic algorithm,the optimum projected normalized emittance for 100 pC bunches with bunch length of 1 mm rms is reduced to 0.1 mm mrad for 100%of the particles and 0.075 mm mrad for 95%of the particles,proving that sub-100 nm emittance can be achieved in the SHINE injector using a single-cell Tsinghua University(THU)VHF gun.This emittance fulfills the requirements not only of SHINE and Linac Coherent Light Source(LCLS)-II but also of LCLS-II-High Energy(LCLS-II-HE).We demonstrate that the optimal emittance in the VHF gun injector is reduced via the optimization of the solenoid geometry,thereby reducing solenoid spherical aberration.Through the inclusion of high-order(H.O.)energy spread among the optimization objectives,the H.O.energy spread can be reduced by a factor of nearly six using a high-harmonic cavity despite a 38%emittance growth.Finally,the beam dynamics in the SHINE main accelerator show that reducing the H.O.energy spread in the injector is of great significance to improving compression efficiency and reducing bunch current spike.展开更多
The impact of the variations of threshold voltage(V_(th))and hold voltage(V_(hold))of threshold switching(TS)selector in1 S1 R crossbar array is investigated.Based on ON/OFF state I–V curves measurements from a large...The impact of the variations of threshold voltage(V_(th))and hold voltage(V_(hold))of threshold switching(TS)selector in1 S1 R crossbar array is investigated.Based on ON/OFF state I–V curves measurements from a large number of Ag-filament TS selectors,V_(th)and V_(hold)are extracted and their variations distribution expressions are obtained,which are then employed to evaluate the impact on read process and write process in 32×321 S1 R crossbar array under different bias schemes.The results indicate that V_(th)and V_(hold)variations of TS selector can lead to degradation of 1 S1 R array performance parameters,such as minimum read/write voltage,bit error rate(BER),and power consumption.For the read process,a small V_(hold)variation not only results in the minimum read voltage increasing but it also leads to serious degradation of BER.As the standard deviation of V_(hold)and V_(th)increases,the BER and the power consumption of 1 S1 R crossbar array under 1/2 bias,1/3 bias,and floating scheme degrade,and the case under 1/2 bias tends to be more serious compared with other two schemes.For the write process,the minimum write voltage also increases with the variation of V_(hold)from small to large value.A slight increase of V_(th)standard deviation not only decreases write power efficiency markedly but also increases write power consumption.These results have reference significance to understand the voltage variation impacts and design of selector properly.展开更多
Low-power and low-variability artificial neuronal devices are highly desired for high-performance neuromorphic computing.In this paper,an oscillation neuron based on a low-variability Ag nanodots(NDs)threshold switchi...Low-power and low-variability artificial neuronal devices are highly desired for high-performance neuromorphic computing.In this paper,an oscillation neuron based on a low-variability Ag nanodots(NDs)threshold switching(TS)device with low operation voltage,large on/off ratio and high uniformity is presented.Measurement results indicate that this neuron demonstrates self-oscillation behavior under applied voltages as low as 1 V.The oscillation frequency increases with the applied voltage pulse amplitude and decreases with the load resistance.It can then be used to evaluate the resistive random-access memory(RRAM)synaptic weights accurately when the oscillation neuron is connected to the output of the RRAM crossbar array for neuromorphic computing.Meanwhile,simulation results show that a large RRAM crossbar array(>128×128)can be supported by our oscillation neuron owing to the high on/off ratio(>10^(8))of Ag NDs TS device.Moreover,the high uniformity of the Ag NDs TS device helps improve the distribution of the output frequency and suppress the degradation of neural network recognition accuracy(<1%).Therefore,the developed oscillation neuron based on the Ag NDs TS device shows great potential for future neuromorphic computing applications.展开更多
Three-finger toxins （TFTs） are well-recognized non- enzymatic venom proteins found in snakes. However, although TFTs exhibit accelerated evolution, the drivers of this evolution remain poorly understood. The structu...Three-finger toxins （TFTs） are well-recognized non- enzymatic venom proteins found in snakes. However, although TFTs exhibit accelerated evolution, the drivers of this evolution remain poorly understood. The structural complexes between long-chain α-neurotoxins, a subfamily of TFTs, and their nicotinic acetylcholine receptor targets have been determined in previous research, providing an opportunity to address such questions. In the current study, we observed several previously identified positively selected sites （PSSs） and the highly variable C-terminal loop of these toxins at the toxin/receptor interface. Of interest, analysis of the molecular adaptation of the toxin-recognition regions in the corresponding receptors provided no statistical evidence for positive selection. However, these regions accumulated abundant amino acid variations in the receptors from the prey of snakes, suggesting that accelerated substitution of TFTs could be a consequence of adaptation to these variations. To the best of our knowledge, this atypical evolution, initially discovered in scorpions, is reported in snake toxins for the first time and may be applicable for the evolution of toxins from other venomous animals.展开更多
The Chinese Grouse(Tetrastes sewerzowi) and Hazel Grouse(T. bonasia) are sibling species that are well-adapted to harsh high-altitude and latitude habitats. In the current study, we sampled and sequenced 29 Chinese Gr...The Chinese Grouse(Tetrastes sewerzowi) and Hazel Grouse(T. bonasia) are sibling species that are well-adapted to harsh high-altitude and latitude habitats. In the current study, we sampled and sequenced 29 Chinese Grouse(n=16) and Hazel Grouse(n=13) from eight locations in China, Sweden,Germany, and northeast Poland to analyze population genetic diversity and structure, introgression, and local adaptation.展开更多
Objective:Hepatocellular carcinoma(HCC)is the most common primary liver cancer,the fifth most common cancer and the third most common global cause of cancer related deaths.Chronic alcohol consumption is a well-known r...Objective:Hepatocellular carcinoma(HCC)is the most common primary liver cancer,the fifth most common cancer and the third most common global cause of cancer related deaths.Chronic alcohol consumption is a well-known risk factor for HCC.Acetaldehyde,a main metabolite of ethanol oxidation.展开更多
We present a novel approach to solve the problem of single channel source separation (SCSS) based on filterbank technique and sparse non-negative matrix two dimensional deconvolution (SNMF2D). The proposed approach do...We present a novel approach to solve the problem of single channel source separation (SCSS) based on filterbank technique and sparse non-negative matrix two dimensional deconvolution (SNMF2D). The proposed approach does not require training information of the sources and therefore, it is highly suited for practicality of SCSS. The major problem of most existing SCSS algorithms lies in their inability to resolve the mixing ambiguity in the single channel observation. Our proposed approach tackles this difficult problem by using filterbank which decomposes the mixed signal into sub-band domain. This will result the mixture in sub-band domain to be more separable. By incorporating SNMF2D algorithm, the spectral-temporal structure of the sources can be obtained more accurately. Real time test has been conducted and it is shown that the proposed method gives high quality source separation performance.展开更多
A digital-controlled measuring instrument for hearing, which is mainly composed of STC11F16EX, AD9833, ISD400416MS and LM1972, is introduced in this paper. It may output highly accurate and purified sine signal whose ...A digital-controlled measuring instrument for hearing, which is mainly composed of STC11F16EX, AD9833, ISD400416MS and LM1972, is introduced in this paper. It may output highly accurate and purified sine signal whose frequency and amplitude are controlled by digital data. Specially, the displaying number of decibel is equal to actual number of decibel because that frequency response of earphone is corrected through software of microcontroller. Additionally, touching buttons, which is simple and convenience to use, is selected. Hence this instrument is convenient to measure and teach about hearing specially, research and study on frequency characteristic of human ear and impedance characteristic of human body in medical science.展开更多
Hanging-drop method has been widely used to fabricate three-dimensional (3D) in vitro tissue models due to its advantages such as being easy to perform, inexpensive, and permitting precise control of cell spheroid for...Hanging-drop method has been widely used to fabricate three-dimensional (3D) in vitro tissue models due to its advantages such as being easy to perform, inexpensive, and permitting precise control of cell spheroid formation. The geometry of hanging drop may play a critical role on the formation of cell spheroids, which, however, has not been explored. In this study, we developed a modified hanging-drop platform that enables the production of cell spheroids in a high-throughput manner by controlling hanging drop geometry with defined spreading ring. The surface tension force is proportional to the spreading ring and gravitational force is determined by the droplet volume, and the geometry can be determined by the balance between surface tension and gravity.β-TC-6 cell spheroids with optimized diameters were fabricated as 3D in vitro islet models. The models show morphology similar to primary islets and have functionality that more closely resembles primary islets than two-dimensional cell culture. The developed platform holds great potential for engineering well-controlled in vitro tissue models for various applications such as physiological and pathological studies, drug screening, as well as transplantation for treatment purpose.展开更多
Nowadays,cardiovascular disease has gradually become the number one killer of human health.The Stanford type-A aortic dissection is a relatively common cardiovascular disease with potential hazards.The disease is caus...Nowadays,cardiovascular disease has gradually become the number one killer of human health.The Stanford type-A aortic dissection is a relatively common cardiovascular disease with potential hazards.The disease is caused by a partialtearing of the aortic intima.Thoracic endovascular aortic repair(TEVAR)is one of the most effective treatment for type A aortic dissection and has been widely used clinically to achieve thrombosis and reduce pressure by covering the incision tear in the FL.However,the effect of entry tear location on type-A aortic dissection and the prognosis of TEVAR intervention are unclear.In this work,the hemodynamic effects of the type-A aortic dissection in different entry and covering entry tear position were mainly studied.It can provide a new method or idea in the field of the aortic dissection hemodynamics,which is of great significance to provide a basic theoretical research on the development of aortic dissection in the aspect of clinical judgment.Two type-A aortic dissection models with different entry tear positions(Model 1:the entry tear was located at the entrance of the ascending aorta,Model 2:the entry tear was located at the starting position of the descending aorta)were reconstructed according to the computed tomography(CT)images of the patients.In our study,the thoracic aortic endovascular repair was simulated by covering the entry tear(Model 3).Then,the semi-automatic adaptive technology HyperMeshl0.0(Altair HyperWorks,Troy,Ml,USA)mesh generator was used to generate the high-quality tetrahedral 3D mesh.To clarify the hemodynamic effects of entry tear and coverage in aortic blood flow pattern,the comparative study on the true lumen(TL)and false lumen(FL)blood flow patterns of three models were carried out numerically(the time-dependent pulsatile waveform of pressure boundary conditions used at the aortic inlet were consistent with Rapezzis’s work,time-dependent pulsatile waveform of velocity at the descending aorta outlet and the time-dependent pulsatile waveform of pressure at the brachiocephalic artery,left common carotid artery,and left subclavian artery were obtained from the work of Olufsenet et al).The velocity vector,flow ratio,pressure,time-average wall shear stress(TAWSS)and relative residence time(RRT)were calculated to evaluate the hemodynamic changes.The results of this work indicated that(Ⅰ)the velocity was higher at the entry tear in aorta entrance;(Ⅱ)the helical development of the TL and FL might be related to the helical nature of aortic arch;(Ⅲ)the blood flow which passing the FL of Model 1,Model 2 and Model 3 in one cardiac cycle were approximately 26.63%,13.39%and 1%,respectively;(Ⅳ)the difference in intima wall pressure among the TL and FL was found varied a lot and shown a strong pulsation;(Ⅴ)the TAWSS distribution in TL and FL were quite different(the TAWSS in TL intima>8 Pa,the TAWSS in FL intima<4 Pa).In brief,the aortic morphology and location of the entry tear were found to have a significant effect on the hemodynamic of the aortic dissection.What’s more,we found that the risk of the aortic rupture could be higher if the position of entry tear is closer to the ascending aorta.By covering the entry tear to simulate TEVAR,the pressure of FL was reduced,which could provide some help for the treatment of early retrograde type-A dissection.展开更多
Alcoholic hepatitis (AH) was first reported in 1961 as an acute disease in alcoholics with severe clinical syndromes including jaundice, anorexia, nausea, upper abdominal pain, hepatomegaly and fever etc. 1 Today, it ...Alcoholic hepatitis (AH) was first reported in 1961 as an acute disease in alcoholics with severe clinical syndromes including jaundice, anorexia, nausea, upper abdominal pain, hepatomegaly and fever etc. 1 Today, it is generally accepted that severe AH is a form of acute - on - chronic liver failure in patients with underlying chronic alcohol - related liver disease ( ALD). The detailed diagnosis of AH was recently defined by the National Institute on Alcohol Abuse and Alcoholism ( NIAAA)- supported consortia and published in 2016. 2 The first diagnostic criterion is alcohol drinking history, which includes heavy drinking > 5 years, recent drinking > 6 months with < 60 days of abstinence before the onset of jaundice, and men with >4 drinks ( 50 -60 g)/day, and women with >3 drinks ( 40 g)/day. The typical clinical sign is jaundice with some non - specific signs and symptoms including malaise, tender hepatomegaly, decompensation (ascites, encephalopathy, bacterial infection, variceal bleeding).展开更多
基金funded by the National Natural Science Foundation of China(NSFC,Grant No.31520103903 to Y.-H.Sun and J.Hoglund)the Biodiversity Conservation Project of the Second Forest and Grass Ecosystem Recovery(Grant No.QHTX-2021-016).
文摘Genetic load and inbreeding are recognized as important factors to be considered in conservation programs.Elevated levels of both can increase the risk of population extinction by negatively impacting fitness-related characters in many species of plants and animals,including humans(inbreeding depression).Genomic tech-niques are increasingly used in measuring and understanding genetic load and inbreeding and their importance in evolution and conservation.We used whole genome resequencing data from two sibling grouse species in subarctic Eurasia to quantify both.We found a large range of inbreeding measured as FROH(fraction of runs of homozygosity)in individuals from different populations of Chinese Grouse(Tetrastes sewerzowi)and Hazel Grouse(T.bonasia).FROH estimated from genome-wide runs of homozygosity(ROH)ranged from 0.02 to 0.24 among Chinese Grouse populations and from 0.01 to 0.44 in Hazel Grouse.Individuals from a population of Chinese Grouse residing in the Qilian mountains and from the European populations of Hazel Grouse(including samples from Sweden,Germany and Northeast Poland)were the most inbred(FROH ranged from 0.10 to 0.23 and 0.11 to 0.44,respectively).These levels are comparable to other highly inbred populations of birds.Hazel Grouse from northern China and Chinese Grouse residing in the Qinghai-Tibetan Plateau showed relatively lower inbreeding levels.Comparisons of the ratio between deleterious missense mutations and synonymous mutations revealed higher levels in Chinese Grouse as compared to Hazel Grouse.These results are possibly explained by higher fixation rates,mutational melt down,in the range-restricted Chinese Grouse compared to the wide-ranging Hazel Grouse.However,when we compared the relatively more severe class of loss-of-function muta-tions,Hazel Grouse had slightly higher levels than Chinese Grouse,a result which may indicate that purifying selection(purging)has been more efficient in Chinese Grouse on this class of mutations.
基金supported in part by the IoT Intelligent Microsystem Center of Tsinghua University-China Mobile Joint Research Institute.
文摘Automated optical inspection(AOI)is a significant process in printed circuit board assembly(PCBA)production lines which aims to detect tiny defects in PCBAs.Existing AOI equipment has several deficiencies including low throughput,large computation cost,high latency,and poor flexibility,which limits the efficiency of online PCBA inspection.In this paper,a novel PCBA defect detection method based on a lightweight deep convolution neural network is proposed.In this method,the semantic segmentation model is combined with a rule-based defect recognition algorithm to build up a defect detection frame-work.To improve the performance of the model,extensive real PCBA images are collected from production lines as datasets.Some optimization methods have been applied in the model according to production demand and enable integration in lightweight computing devices.Experiment results show that the production line using our method realizes a throughput more than three times higher than traditional methods.Our method can be integrated into a lightweight inference system and pro-mote the flexibility of AOI.The proposed method builds up a general paradigm and excellent example for model design and optimization oriented towards industrial requirements.
基金funded by the Poyang Lake Water Conservancy Project Office of the Department of Water Resources,Jiangxi Province,China(KT201537)the National Natural Science Foundation of China(Grant No.32360285)the National Geographic Air and Water Con-servation Fund(GEFC07-15).
文摘For migratory waterbirds,the quality of wintering habitat is related to spring migration and successful breeding in the next year.The availability of food resources in the habitat is critical and varies within water levels.Although the water-level fluctuations in Poyang Lake have been extremely variable interannually in recent years,the wintering waterbird populations have remained relatively stable.Hence,the mechanism of maintaining the stability is worth exploring.This study aimed to compare the distribution of vegetation and herbivorous wa-terbirds in 2015-2016 and 2016-2017,focusing on three shallow sub-lakes and one main lake are.The results showed that the emergence of tubers and the growth of Carex spp.provided a continuous food supply and habitat for wintering waterbirds with a gradual decline in the water level.Shallow sub-lakes supported almost all of the tuber-eating waterbirds(1.42-1.62×10^(5))and most geese(1.34-1.53×10^(6)).However,the main lake area,covered with Persicaria hydropiper,did not provide adequate and accessible food.This resulted in almost no distribution of tuber-eating waterbirds,with only a few geese congregating in early winter.Our results demonstrated that the shallow sub-lakes under human control provided a different environment from the main lake and are key to sustaining the successful wintering of hundreds of thousands of migratory waterbirds in Poyang Lake.Therefore,we recommend refining the anthropogenic management of the shallow sub-lakes to regulate the water level to ensure the carrying capacity of Poyang Lake.
文摘Migration of vascular smooth muscle cells (VSMCs) from the media to intima constitutes a critical step in the development of proliferative vascular diseases. To elucidate the regulatory mechanism of VSMCs motility, the roles of caldesmon (CaD) were investigated previously. CaD is an actin-binding protein dynamically regulating cytoskeleton structure. In this study, the potential role of CaD in mediating proliferation and motility of VSMCs were discussed. First, structural effect of CaD on cytoskeleton integrity was analyzed with CaD knock-down;second, the proliferation of VSMCs was measured in CaD knock-down and control cells;third, the specific role of CaD on VSMCs motilities was evaluated with in vitro migration and invasion assays. We found that CaD is an integral component to maintain cytoskeleton integrity of VSMCs. Our data indicated that CaD suppression does not show significant influence on VSMCs proliferation, but negatively modulates the motilities of VSMCs, and CaD depletion would significantly facilitate migration and invasion of VSMCs.
文摘The course ROS Robot Programming Practice is designed to equip students with both the foundational principles and practical applications of the Robot Operating System(ROS)through structured instruction and hands-on exercises.This paper summarizes the course’s pedagogical approach and the insights gained from its implementation,focusing on key areas such as the practical teaching platform,instructional system,teaching methods,and evaluation mechanisms.The practical teaching platform incorporates robotic arms and mobile robots,along with commonly used sensors,to engage students and stimulate their interest in robotics.A well-structured teaching system is employed,guiding students through a series of experiments-ranging from basic tasks to modeling and simulation experiments,sensor experiments,mobile robot tasks,robotic arm exercises,and comprehensive project practices.Regarding teaching methods,a blended learning approach and progressive instructional model are utilized to ensure active student participation.This approach follows a logical progression,starting with fundamental ROS knowledge,advancing to robot applications,and culminating in comprehensive project-based practice.In terms of evaluation,a dual approach combining process and outcome assessments is employed,ensuring that students’performance is evaluated comprehensively through various metrics.
文摘Heat shock protein 47 (HSP47) is a collagen-specific molecular chaperone that is required for mo-lecular maturation of various types of collagens. Many studies have shown a close association be-tween increased expression of HSP47 and excessive accumulation of collagens in scar tissues of various human fibrotic diseases. However, the role of HSP47 in formation of scar after glaucoma filtration surgery is still unclear. In this study, we deleted the expression of HSP47 in human tent on fibroblasts (HTFs) by virus infection, and then the proliferation and collagen synthesis were compared between HSP47 deletion cells and control upon TGF-β1 stimulation. Our data showed that HSP47 deletion could significantly inhibit the proliferation and collagen synthesis of HTFs upon TGF-β1 stimulation, HSP47 gene suppression might be a novel method to against the formation of scar after glaucoma surgery.
基金China Postdoctoral Science Foundation,Grant/Award Number:2019M661825Natural Science Foundation of Jiangsu Province,Grant/Award Numbers:BK20190413,BK20210616Japan Society。
文摘Aprotic lithium–oxygen batteries(LOBs)have been recognized as novel energy storage devices for their outstanding specific energy density,while the large discharge/charge overpotential is a tough barrier to be overcome.Here,hetero-structured MoS_(2)/ZnIn_(2)S_(4) nanosheets have been prepared to capture visible light and the generated charge carriers are utilized for promoting both the oxygen reduction reaction and the oxygen evolution reaction.With the light illumination in the discharge process,the abundant photo-inspired electrons serve as the reaction sites to promote the reduction of O_(2) into LiO_(2) which is finally deposited as Li_(2)O_(2).On the contrary,the generated holes in the valence band can contribute to the low oxidization potential of Li_(2)O_(2) during the charge process.It delivers a low charge potential of 3.29 V,with an excellent resulting energy efficiency of 96.7%,much superior to that of 69.2%in the dark condition.It is noted that the involvement of photoelectrons has influenced the growth of Li_(2)O_(2) films on the MoS_(2)/ZnIn_(2)S_(4) nanosheets through the surface-adsorption pathway.The insights from the theoretical calculation confirm that the photoelectrons favor the absorption of LiO_(2) and the formation of the Li_(2)O_(2) film through the surface route.Therefore,this paper provides a deeper understanding of the mechanism of photoinspired charge carriers in LOBs and will enable further exploration of photo-involved energy storage systems.
文摘Very-high-frequency(VHF)gun photoinjectors,capable of producing high-brightness and high-repetitionrate electron bunches,are some of the best electron sources for driving MHz-class repetition-rate free-electron lasers.In this study,the beam dynamics optimization of a VHF gun photoinjector for Shanghai HIgh Repetition Rate X-ray Free Electron Laser and Extreme Light Facility(SHINE)is systematically demonstrated using a genetic algorithm.Through the inclusion of the solenoid geometry as an optimization variable into the genetic algorithm,the optimum projected normalized emittance for 100 pC bunches with bunch length of 1 mm rms is reduced to 0.1 mm mrad for 100%of the particles and 0.075 mm mrad for 95%of the particles,proving that sub-100 nm emittance can be achieved in the SHINE injector using a single-cell Tsinghua University(THU)VHF gun.This emittance fulfills the requirements not only of SHINE and Linac Coherent Light Source(LCLS)-II but also of LCLS-II-High Energy(LCLS-II-HE).We demonstrate that the optimal emittance in the VHF gun injector is reduced via the optimization of the solenoid geometry,thereby reducing solenoid spherical aberration.Through the inclusion of high-order(H.O.)energy spread among the optimization objectives,the H.O.energy spread can be reduced by a factor of nearly six using a high-harmonic cavity despite a 38%emittance growth.Finally,the beam dynamics in the SHINE main accelerator show that reducing the H.O.energy spread in the injector is of great significance to improving compression efficiency and reducing bunch current spike.
基金Project supported by the MOST of China(Grant No.2016YFA0201801)the Beijing Advanced Innovation Center for Future Chip(ICFC)+2 种基金Beijing Municipal Science and Technology Project(Grant No.D161100001716002)the National Natural Science Foundation of China(Grant Nos.61674089,61674087,61674092,61076115,and 61774012)the Research Fund from Beijing Innovation Center for Future Chip(Grant No.KYJJ2016008)
文摘The impact of the variations of threshold voltage(V_(th))and hold voltage(V_(hold))of threshold switching(TS)selector in1 S1 R crossbar array is investigated.Based on ON/OFF state I–V curves measurements from a large number of Ag-filament TS selectors,V_(th)and V_(hold)are extracted and their variations distribution expressions are obtained,which are then employed to evaluate the impact on read process and write process in 32×321 S1 R crossbar array under different bias schemes.The results indicate that V_(th)and V_(hold)variations of TS selector can lead to degradation of 1 S1 R array performance parameters,such as minimum read/write voltage,bit error rate(BER),and power consumption.For the read process,a small V_(hold)variation not only results in the minimum read voltage increasing but it also leads to serious degradation of BER.As the standard deviation of V_(hold)and V_(th)increases,the BER and the power consumption of 1 S1 R crossbar array under 1/2 bias,1/3 bias,and floating scheme degrade,and the case under 1/2 bias tends to be more serious compared with other two schemes.For the write process,the minimum write voltage also increases with the variation of V_(hold)from small to large value.A slight increase of V_(th)standard deviation not only decreases write power efficiency markedly but also increases write power consumption.These results have reference significance to understand the voltage variation impacts and design of selector properly.
基金supported in part by China Key Research and Development Program(2016YFA0201800)the National Natural Science Foundation of China(91964104,61974081)。
文摘Low-power and low-variability artificial neuronal devices are highly desired for high-performance neuromorphic computing.In this paper,an oscillation neuron based on a low-variability Ag nanodots(NDs)threshold switching(TS)device with low operation voltage,large on/off ratio and high uniformity is presented.Measurement results indicate that this neuron demonstrates self-oscillation behavior under applied voltages as low as 1 V.The oscillation frequency increases with the applied voltage pulse amplitude and decreases with the load resistance.It can then be used to evaluate the resistive random-access memory(RRAM)synaptic weights accurately when the oscillation neuron is connected to the output of the RRAM crossbar array for neuromorphic computing.Meanwhile,simulation results show that a large RRAM crossbar array(>128×128)can be supported by our oscillation neuron owing to the high on/off ratio(>10^(8))of Ag NDs TS device.Moreover,the high uniformity of the Ag NDs TS device helps improve the distribution of the output frequency and suppress the degradation of neural network recognition accuracy(<1%).Therefore,the developed oscillation neuron based on the Ag NDs TS device shows great potential for future neuromorphic computing applications.
基金supported by the National Natural Science Foundation of China(Grant No.31570773)State Key Laboratory of Integrated Management of Pest Insects and Rodents(Chinese IPM1707)
文摘Three-finger toxins （TFTs） are well-recognized non- enzymatic venom proteins found in snakes. However, although TFTs exhibit accelerated evolution, the drivers of this evolution remain poorly understood. The structural complexes between long-chain α-neurotoxins, a subfamily of TFTs, and their nicotinic acetylcholine receptor targets have been determined in previous research, providing an opportunity to address such questions. In the current study, we observed several previously identified positively selected sites （PSSs） and the highly variable C-terminal loop of these toxins at the toxin/receptor interface. Of interest, analysis of the molecular adaptation of the toxin-recognition regions in the corresponding receptors provided no statistical evidence for positive selection. However, these regions accumulated abundant amino acid variations in the receptors from the prey of snakes, suggesting that accelerated substitution of TFTs could be a consequence of adaptation to these variations. To the best of our knowledge, this atypical evolution, initially discovered in scorpions, is reported in snake toxins for the first time and may be applicable for the evolution of toxins from other venomous animals.
基金supported by the National Natural Science Foundation of China(31520103903)。
文摘The Chinese Grouse(Tetrastes sewerzowi) and Hazel Grouse(T. bonasia) are sibling species that are well-adapted to harsh high-altitude and latitude habitats. In the current study, we sampled and sequenced 29 Chinese Grouse(n=16) and Hazel Grouse(n=13) from eight locations in China, Sweden,Germany, and northeast Poland to analyze population genetic diversity and structure, introgression, and local adaptation.
文摘Objective:Hepatocellular carcinoma(HCC)is the most common primary liver cancer,the fifth most common cancer and the third most common global cause of cancer related deaths.Chronic alcohol consumption is a well-known risk factor for HCC.Acetaldehyde,a main metabolite of ethanol oxidation.
文摘We present a novel approach to solve the problem of single channel source separation (SCSS) based on filterbank technique and sparse non-negative matrix two dimensional deconvolution (SNMF2D). The proposed approach does not require training information of the sources and therefore, it is highly suited for practicality of SCSS. The major problem of most existing SCSS algorithms lies in their inability to resolve the mixing ambiguity in the single channel observation. Our proposed approach tackles this difficult problem by using filterbank which decomposes the mixed signal into sub-band domain. This will result the mixture in sub-band domain to be more separable. By incorporating SNMF2D algorithm, the spectral-temporal structure of the sources can be obtained more accurately. Real time test has been conducted and it is shown that the proposed method gives high quality source separation performance.
文摘A digital-controlled measuring instrument for hearing, which is mainly composed of STC11F16EX, AD9833, ISD400416MS and LM1972, is introduced in this paper. It may output highly accurate and purified sine signal whose frequency and amplitude are controlled by digital data. Specially, the displaying number of decibel is equal to actual number of decibel because that frequency response of earphone is corrected through software of microcontroller. Additionally, touching buttons, which is simple and convenience to use, is selected. Hence this instrument is convenient to measure and teach about hearing specially, research and study on frequency characteristic of human ear and impedance characteristic of human body in medical science.
基金the National Natural Science Foundation of China (Grants 51605377 and 81300696)the Natural Science Foundation of Shaanxi Province (Grant 2017JQ5004).
文摘Hanging-drop method has been widely used to fabricate three-dimensional (3D) in vitro tissue models due to its advantages such as being easy to perform, inexpensive, and permitting precise control of cell spheroid formation. The geometry of hanging drop may play a critical role on the formation of cell spheroids, which, however, has not been explored. In this study, we developed a modified hanging-drop platform that enables the production of cell spheroids in a high-throughput manner by controlling hanging drop geometry with defined spreading ring. The surface tension force is proportional to the spreading ring and gravitational force is determined by the droplet volume, and the geometry can be determined by the balance between surface tension and gravity.β-TC-6 cell spheroids with optimized diameters were fabricated as 3D in vitro islet models. The models show morphology similar to primary islets and have functionality that more closely resembles primary islets than two-dimensional cell culture. The developed platform holds great potential for engineering well-controlled in vitro tissue models for various applications such as physiological and pathological studies, drug screening, as well as transplantation for treatment purpose.
基金funded by the National Natural Science Foundation of China ( 11602007,11572014, 11832003)Key research and development program ( 2017YFC0111104)New Talent ( 015000514118002)
文摘Nowadays,cardiovascular disease has gradually become the number one killer of human health.The Stanford type-A aortic dissection is a relatively common cardiovascular disease with potential hazards.The disease is caused by a partialtearing of the aortic intima.Thoracic endovascular aortic repair(TEVAR)is one of the most effective treatment for type A aortic dissection and has been widely used clinically to achieve thrombosis and reduce pressure by covering the incision tear in the FL.However,the effect of entry tear location on type-A aortic dissection and the prognosis of TEVAR intervention are unclear.In this work,the hemodynamic effects of the type-A aortic dissection in different entry and covering entry tear position were mainly studied.It can provide a new method or idea in the field of the aortic dissection hemodynamics,which is of great significance to provide a basic theoretical research on the development of aortic dissection in the aspect of clinical judgment.Two type-A aortic dissection models with different entry tear positions(Model 1:the entry tear was located at the entrance of the ascending aorta,Model 2:the entry tear was located at the starting position of the descending aorta)were reconstructed according to the computed tomography(CT)images of the patients.In our study,the thoracic aortic endovascular repair was simulated by covering the entry tear(Model 3).Then,the semi-automatic adaptive technology HyperMeshl0.0(Altair HyperWorks,Troy,Ml,USA)mesh generator was used to generate the high-quality tetrahedral 3D mesh.To clarify the hemodynamic effects of entry tear and coverage in aortic blood flow pattern,the comparative study on the true lumen(TL)and false lumen(FL)blood flow patterns of three models were carried out numerically(the time-dependent pulsatile waveform of pressure boundary conditions used at the aortic inlet were consistent with Rapezzis’s work,time-dependent pulsatile waveform of velocity at the descending aorta outlet and the time-dependent pulsatile waveform of pressure at the brachiocephalic artery,left common carotid artery,and left subclavian artery were obtained from the work of Olufsenet et al).The velocity vector,flow ratio,pressure,time-average wall shear stress(TAWSS)and relative residence time(RRT)were calculated to evaluate the hemodynamic changes.The results of this work indicated that(Ⅰ)the velocity was higher at the entry tear in aorta entrance;(Ⅱ)the helical development of the TL and FL might be related to the helical nature of aortic arch;(Ⅲ)the blood flow which passing the FL of Model 1,Model 2 and Model 3 in one cardiac cycle were approximately 26.63%,13.39%and 1%,respectively;(Ⅳ)the difference in intima wall pressure among the TL and FL was found varied a lot and shown a strong pulsation;(Ⅴ)the TAWSS distribution in TL and FL were quite different(the TAWSS in TL intima>8 Pa,the TAWSS in FL intima<4 Pa).In brief,the aortic morphology and location of the entry tear were found to have a significant effect on the hemodynamic of the aortic dissection.What’s more,we found that the risk of the aortic rupture could be higher if the position of entry tear is closer to the ascending aorta.By covering the entry tear to simulate TEVAR,the pressure of FL was reduced,which could provide some help for the treatment of early retrograde type-A dissection.
文摘Alcoholic hepatitis (AH) was first reported in 1961 as an acute disease in alcoholics with severe clinical syndromes including jaundice, anorexia, nausea, upper abdominal pain, hepatomegaly and fever etc. 1 Today, it is generally accepted that severe AH is a form of acute - on - chronic liver failure in patients with underlying chronic alcohol - related liver disease ( ALD). The detailed diagnosis of AH was recently defined by the National Institute on Alcohol Abuse and Alcoholism ( NIAAA)- supported consortia and published in 2016. 2 The first diagnostic criterion is alcohol drinking history, which includes heavy drinking > 5 years, recent drinking > 6 months with < 60 days of abstinence before the onset of jaundice, and men with >4 drinks ( 50 -60 g)/day, and women with >3 drinks ( 40 g)/day. The typical clinical sign is jaundice with some non - specific signs and symptoms including malaise, tender hepatomegaly, decompensation (ascites, encephalopathy, bacterial infection, variceal bleeding).
