Analytical method for the distributions of axial-load and stress is based on elastic assumption, but the threaded connections are often in plastic deformation stage in practice. Meanwhile the strain in the threaded co...Analytical method for the distributions of axial-load and stress is based on elastic assumption, but the threaded connections are often in plastic deformation stage in practice. Meanwhile the strain in the threaded connection is difficult to measure. So it is necessary to study the reliable numerical method. At present neither the convergence analysis of the computational results nor the elastic-plastic analysis in the loading-unloading process are studied. In this paper, von Mises plasticity and kinematic hardening model is used to describe the material response. A new convergence criterion for nonlinear finite element analysis of the loading-unloading process is proposed. An axisymmetric finite element model according to the proposed convergence criterion is developed and used to analyze the distributions of axial-load and stress. It can be conclude that the stress distribution analysis is more dependent on the mesh density than the axial-load distribution analysis. The stress distribution result indicates that with increasing of applied load, the engaged threads close to the nut-bearing surface become plastic firstly. The axial-load distribution result reveals that the load percentage carried by single thread depends on the position of thread and load intensity. When the load is relatively small, the applied load is mainly carried by the engaged threads near the nut-bearing surface, when the load is larger, the differences of percentages for all threads become small. The proposed convergence analyzing procedure is applicable for other nonlinear analyses. The obtained distributions of axial-load and stress can be a reference of engineering application.展开更多
AIM: To investigate the anti-tumor mechanism of antisenseoligodeoxynucleotide cantide against hTERT.METHODS: Tumor cells were cultured overnight and grownto 50-60% confluence. HepG2 and SMMC-7721 were treatedwith cant...AIM: To investigate the anti-tumor mechanism of antisenseoligodeoxynucleotide cantide against hTERT.METHODS: Tumor cells were cultured overnight and grownto 50-60% confluence. HepG2 and SMMC-7721 were treatedwith cantide mixed with lipofectin, or lipofectin alone. Afterinducted for 6 h at 37℃, 10% FCS in DMEM was replacedin each well. After the treatment repeated twice to threetimes in each concentration of cantide, hTERT mRNA andprotein expression were measured by RT-PCR and Westernblot analysis, respectively. Telomerase aclivity was determinedby TRAP-ELISA assay. CPP32- and ICE-like activity was alsoinvestigated using CasPACE assay system at 48 h aftercantide treatment, and apoptosis was evaluated using theDeadEnd assay at 24, 48 and 72 h after cantide treatment.RESULTS: Compared to the control cells, the cells treated with cantide showed a dose-dependent decrease in hTERT mRNA levels at 24 h and in protein levels at 48 h respectively.The telomerase activity was decreased as the concentration of cantide increased at 48 h. At the concentration of 800 nM,the telomerase activity in the treated HepG2 and SMMC7721 cells was only 17.1% (P＜0.01) and 20.3% (P＜0.01)of that in untreated cells. The levels of CPP32-like protease activity in HepG2 and SMMC-7721 increased by 2.8- and 3.0-fold (P＜0.05) at 48 h, and the levels of ICE-like protease activity also increased by 2.6- and 3.2-fold (P＜0.05)respectively. The percentage of apoptosis in HepG2 and SMMC-7721 cells treated with 800 nM cantide at 72 h was 63% and 52% (P＜0.01), respectively. By contrast, 8%and 9% of the cells were apoptosis after 72 h treatment with lipofectin alone.CONCLUSION: Cantide can decrease telomerase activity by inhibiting the expression of hTERT gene and has a rapid anti-tumor effect through inducing the Caspase-dependent apoptosis. The rapid inhibitory effect of cantide on tumor growth demonstrates its feasibility in cancer treatment.展开更多
The correlations of isotopic ratios in precipitation with temperature, air pressure and humidity at dif- ferent altitudes, in southwest China, are analyzed. There appear marked negative correlations for the δ 18O in ...The correlations of isotopic ratios in precipitation with temperature, air pressure and humidity at dif- ferent altitudes, in southwest China, are analyzed. There appear marked negative correlations for the δ 18O in precipitation with precipitation amount, vapor pressure and atmospheric precipitable water (PW) at Mengzi, Simao and Tengchong stations on synoptic timescale; the marked negative correlations between the δ 18O in precipitation and the diurnal mean temperature at 400 hPa, 500 hPa, 700 hPa and 850 hPa are different from the temperature effect in middle-high-latitude inland. Moreover, the notable positive correlation between the δ 18O in precipitation and the dew-point deficit △Td at different altitudes is found at the three stations. On annual timescale, the annual precipitation amount weighted mean δ 18O display the negative correlations not only with annual precipitation but also with annual mean temperature at 500 hPa. It can be deduced that, in the years with abnormally strong summer monsoon, more warm and wet air from low-latitude oceans is transported northward along the vapor channel located in southwest China and generates abnormally strong rainfall on the way. Meanwhile, the ab- normally strong condensation process will release more condensed latent heat into atmosphere, and lead to the rise of atmospheric temperature during rainfall, but decline of the δ 18O in precipitation. On the contrary, in the years with abnormally weak summer monsoon, the abnormally weak condensation process will release less condensed latent heat into atmosphere, and lead to the decline of atmos- pheric temperature during rainfall, but increase of the δ 18O in precipitation.展开更多
About 30 million hectares of rice are cultivated annually in China(FAOSTAT,2019).Because most rice fields are wellirrigated and suitable for fish living(‘fish’here refers to various aquatic animals like carps,prawns...About 30 million hectares of rice are cultivated annually in China(FAOSTAT,2019).Because most rice fields are wellirrigated and suitable for fish living(‘fish’here refers to various aquatic animals like carps,prawns,crabs,soft shell turtles,etc.)(Fernando,1993),many efforts have been made to determine how well rice farming and aquaculture can be coupled as a rice-fish system(RFS),of which the same land and water produces both rice and aquatic products.With the technological guidance of RFSs and political supports from the Ministry of Agriculture and Rural Affairs of China since 2010(Supplemental Table 1),multiple types of large-scale,high-efficiency and technologically intensive RFSs are now being demonstrated in the main rice-growing areas of China(National Fisheries Technology Extension Centre,2019),and in total about 1.2 million hectares of rice fields are under RFSs.展开更多
OBJECTIVE: To observe the effect of compound Zhebei granules(CZBG) with chemotherapy in the treatment of refractory acute leukemia.METHODS: In this multicenter, double-blind, placebo-controlled clinical trial, we used...OBJECTIVE: To observe the effect of compound Zhebei granules(CZBG) with chemotherapy in the treatment of refractory acute leukemia.METHODS: In this multicenter, double-blind, placebo-controlled clinical trial, we used a central(online) randomization system to assign 235 patients to two treatment groups. A total of 118 patients received chemotherapy combined with CZBG(4 g,twice daily) and 117 patients received chemotherapy plus placebo. The clinical efficacy was evaluated at the end of one chemotherapeutic cycle.RESULTS: In the full analysis set, in which deaths due to disease progression were regarded as inefficacy, the rates of complete remission(CR) and partial remission(CR + PR) were 32.35% and 50.00%,respectively, for the chemotherapy combined with CZBG group, and 23.08% and 35.58%, respectively,for the chemotherapy plus placebo group. There was a statistically significant difference between the two groups according to a ysis set(PPχ2test(P < 0.05). In the per protocol analS), the CR(33.67%),CR+PR(52.04%) response rates for the chemotherapy plus CZBG group were significantly different from the response rates of the control group(CR:24.24% and CR+PR: 37.37%), respectively(P < 0.05).CONCLUSION: CZBG plus chemotherapy can improve the clinical remission rate of refractory acute leukemia after one just one therapeutic cycle.展开更多
Flexible,compact,lightweight and sustainable power sources are indispensable for modern wearable and personal electronics and small-unmanned aerial vehicles(UAVs).Hierarchical honeycomb has the unique merits of compac...Flexible,compact,lightweight and sustainable power sources are indispensable for modern wearable and personal electronics and small-unmanned aerial vehicles(UAVs).Hierarchical honeycomb has the unique merits of compact mesostructures,excellent energy absorption properties and considerable weight to strength ratios.Herein,a honeycomb-inspired triboelectric nanogenerator(h-TENG)is proposed for biomechanical and UAV morphing wing energy harvesting based on contact triboelectrification wavy surface of cellular honeycomb structure.The wavy surface comprises a multilayered thin film structure(combining polyethylene terephthalate,silver nanowires and fluorinated ethylene propylene)fabricated through high-temperature thermoplastic molding and wafer-level bonding process.With superior synchronization of large amounts of energy generation units with honeycomb cells,the manufactured h-TENG prototype produces the maximum instantaneous open-circuit voltage,short-circuit current and output power of 1207 V,68.5μA and 12.4 mW,respectively,corresponding to a remarkable peak power density of 0.275 mW cm^(−3)(or 2.48 mW g^(−1))under hand pressing excitations.Attributed to the excellent elastic property of self-rebounding honeycomb structure,the flexible and transparent h-TENG can be easily pressed,bent and integrated into shoes for real-time insole plantar pressure mapping.The lightweight and compact h-TENG is further installed into a morphing wing of small UAVs for efficiently converting the flapping energy of ailerons into electricity for the first time.This research demonstrates this new conceptualizing single h-TENG device’s versatility and viability for broad-range real-world application scenarios.展开更多
Ingestive-related behaviors including feeding and ruminating are important indexes to measure the health and welfare of dairy cows.The purpose of this study is to develop a method based on triaxial acceleration to aut...Ingestive-related behaviors including feeding and ruminating are important indexes to measure the health and welfare of dairy cows.The purpose of this study is to develop a method based on triaxial acceleration to automatically recognize feeding and ruminating of dairy cows.During the experiment,five diary cows raised in a barn were used as experimental subjects.A triaxial acceleration sensor was used as the device to collect jawmovement data of dairy cows,and the behaviors of dairy cows were classified into three categories:feeding,ruminating and other behavior.The features of time-domain and frequency-domain were extracted from the raw acceleration data.Three machine learning algorithms including k-nearest neighbor,support vector machine and probabilistic neural network were used for the classification and the results based on four different data segment lengths were compared.The results show that the three algorithms can be used for recognition of feeding and ruminating with high accuracy.Under the condition that the sampling frequency of the sensor is 5 Hz,the combination of data segment length of 256 and k-nearest neighbor algorithm is the best scheme for recognition of feeding and ruminating in this study.The precision and recall of recognition for feeding were 92.8%and 95.6%respectively,and those of recognition for ruminating were 93.7%and 94.3%respectively.The specificity and AUC of recognition for feeding were 96.1%and 0.959 respectively,and those of recognition for ruminating were 97.5%and 0.959 respectively.This will provide an effective method for real-time monitoring of ingestive-related behaviors of dairy cows and lay a foundation for prediction of dairy cows’health status and welfare to further achieve the purpose of disease prediction and adjusting feeding and management methods.展开更多
One of the critical issues for electret/triboelectric devices is the poor charge viability and stability in humid environments.Herein,we propose a new origami-inspired“W-tube”-shaped triboelectric nanogenerator(W-TE...One of the critical issues for electret/triboelectric devices is the poor charge viability and stability in humid environments.Herein,we propose a new origami-inspired“W-tube”-shaped triboelectric nanogenerator(W-TENG)with two thin-film electrets folded based on Miura-origami.The Miura-origami fold is capable of transforming flat materials with large surface areas into reduced and compressed complex 3D structures with parallelogram tessellations.The triboelectric power generation components can thus be hermetically sealed inside the“W-tube”to avoid contact with the external humid environment.Furthermore,the elastic nature of the Miura-origami fold endows the proposed W-TENG device with excellent deformability,flexibility,and stretchability.Therefore,it is capable of harvesting kinetic energy from various directions and forms of movement,including horizontal pressing,vertical tapping,and lateral bending.The compact,light weight,and self-rebounding properties of the origami structure also make it convenient for integration into wearable devices.Various parameters of the W-TENG are intensively investigated,including the number of power generation units,original height of the device,acceleration magnitude,excitation direction,and water-proof capability.Triggered by hand tapping impulse excitation in the horizontal and vertical directions,the instantaneous open-circuit voltages can reach 791 V and 116 V with remarkable optimum powers of 691μW at 50MΩand 220μW at 35 MΩ,respectively.The outcomes of this work demonstrate the fusion of the ancient art of origami,material science,and energy conversion techniques to realize flexible,multifunctional,and water-proof TENG devices.展开更多
Electrochemical reduction of molecular O2 to hydrogen peroxide(H2O2)offers a promising solution for water purification and environmental remediation.Here,we design a hierarchical free-standing single-Co-atom(with Co-N...Electrochemical reduction of molecular O2 to hydrogen peroxide(H2O2)offers a promising solution for water purification and environmental remediation.Here,we design a hierarchical free-standing single-Co-atom(with Co-N4 coordination)electrode for oxygen reduction reaction(ORR)via a two-electron pathway to make H2O2 in acidic media.The current density of the single-Co-atom electrode reached 51 mA/cm2 at 0.1 V vs reversible hydrogen electrode,lasting for more than 10 hours of continuous operation with H2O2 selectivity greater than 80%.Toward practical application,the single-Co-atom electrode was directly used to assemble an electrochemical cell to produce H2O2 at a rate of 676 mol/kgcat/h with a cell voltage of about 1.6 V.展开更多
Amorphous alloys,also known as metallic glasses,are solid metallic materials having long-range disordered atomic structures.Compared to crystalline alloys,amorphous alloys not only have metallic characters,but also po...Amorphous alloys,also known as metallic glasses,are solid metallic materials having long-range disordered atomic structures.Compared to crystalline alloys,amorphous alloys not only have metallic characters,but also possess several distinct properties associated to the amorphous structure,such as isotropy,composition flexibility,unsaturated surface,etc.As a result,amorphous alloys offer a class of highly promising materials for catalyzing electrochemical reactions.In this minireview,the preparation,characterization and electrocatalytic performances of a variety of metallic amorphous alloy materials are summarized.The influences of the amorphous alloy structure on different electrochemical reactions are discussed.Finally,a summary on the advantages and challenges of amorphous alloys in electrocatalysis is provided,along with some perspectives about the future research directions.展开更多
The time series of accumulation in recent 300 years correlated well with solar activity in Dasuopu ice core. Results of spectrum analysis on the accumulation time series of the Dasuopu ice core shows that there are so...The time series of accumulation in recent 300 years correlated well with solar activity in Dasuopu ice core. Results of spectrum analysis on the accumulation time series of the Dasuopu ice core shows that there are some periods that coincide with the periods of solar activity. By comparing the long-time change trend of the accumulation in the Dasuopu ice core with various kinds of indexes of solar activity intensity, a negative correlation is found between the trend and solar activity.展开更多
Nano-sized γ-alumina （γ-Al2O3） was first prepared by a precipitation method. Then, active component of cobalt and a series of alkaline- earth metal promoters or nickel （Ni） with different contents were loaded on...Nano-sized γ-alumina （γ-Al2O3） was first prepared by a precipitation method. Then, active component of cobalt and a series of alkaline- earth metal promoters or nickel （Ni） with different contents were loaded on the γ-Al2O3 support. The catalysts were characterized by N2 adsorption-desorption, X-ray diffraction （XRD） and thermogravimetry analysis （TGA）. The activity and selectivity of the catalysts in catalytic partial oxidation （CPO） of methane have been compared with Co/γ-Al2O3, and it is found that the catalytic activity, selectivity, and stability are enhanced by the addition of alkaline-earth metals and nickel. The optimal loadings of strontium （Sr） and Ni were 6 and 4 wt%, respectively. This finding will be helpful in designing the trimetallic Co-Ni-Sr/γ-Al2O3 catalysts with high performance in CPO of methane展开更多
Coughing is an obvious respiratory disease symptom,which affects the airways and lungs of pigs.In pig houses,continuous online monitoring of cough sounds can be used to build an intelligent alarm system for disease ea...Coughing is an obvious respiratory disease symptom,which affects the airways and lungs of pigs.In pig houses,continuous online monitoring of cough sounds can be used to build an intelligent alarm system for disease early detection.Owing to complicated interferences in piggery,recognition of pig cough sound becomes difficult.Although a lot of algorithms have been proposed to recognize the pig cough sounds,the recognition accuracy in field sit-uations still needs enhancement.The purpose of this research is to provide a highly accu-rate pig cough recognition method for the respiratory disease alarm system.We propose a classification algorithm based on the fine-tuned AlexNet model and feature of the spectro-gram.With the advantages of the convolutional neural network in image recognition,the sound signals are converted into spectrogram images for recognition,to enhance the accu-racy.We compare the proposed algorithm’s performance with the probabilistic neural net-work classifier and some existing algorithms.The results reveal that the proposed algorithm significantly outperforms the other algorithms-cough and overall recognition accuracies reach to 96.8%and 95.4%,respectively,with 96.2%F1-score achieved.展开更多
As an extension of the traditional encryption technology,information hiding has been increasingly used in the fields of communication and network media,and the covert communication technology has gradually developed.T...As an extension of the traditional encryption technology,information hiding has been increasingly used in the fields of communication and network media,and the covert communication technology has gradually developed.The blockchain technology that has emerged in recent years has the characteristics of decentralization and tamper resistance,which can effectively alleviate the disadvantages and problems of traditional covert communication.However,its combination with covert communication thus far has been mostly at the theoretical level.The BLOCCE method,as an early result of the combination of blockchain and covert communication technology,has the problems of low information embedding efficiency,the use of too many Bitcoin addresses,low communication efficiency,and high costs.The present research improved on this method,designed the V-BLOCCE which uses base58 to encrypt the plaintext and reuses the addresses generated by Vanitygen multiple times to embed information.This greatly improves the efficiency of information embedding and decreases the number of Bitcoin addresses used.Under the premise of ensuring the order,the Bitcoin transaction OP_RETURN field is used to store the information required to restore the plaintext and the transactions are issued at the same time to improve the information transmission efficiency.Thus,a more efficient and feasible method for the application of covert communication on the blockchain is proposed.In addition,this paper also provides a more feasible scheme and theoretical support for covert communication in blockchain.展开更多
Objective Alkaline comet assay was used to evaluate DNA repair (nucleotide excision repair, NER) capacity of human fresh lymphocytes from 12 young healthy non-smokers (6 males and 6 females). Methods Lymphocytes were ...Objective Alkaline comet assay was used to evaluate DNA repair (nucleotide excision repair, NER) capacity of human fresh lymphocytes from 12 young healthy non-smokers (6 males and 6 females). Methods Lymphocytes were exposed to UV-C (254 nm) at the dose rate of 1.5 J/m2/sec. Novobiocin (NOV) and aphidicolin (APC), DNA repair inhibitors, were utilized to imitate the deficiency of DNA repair capacity at the incision and ligation steps of NER. Lymphocytes from each donor were divided into three grougs: UVC group, UVC plus NOV group, and UVC plus APC group. DNA single strand breaks were detected in UVC irradiated cells incubated for 0, 30, 60, 90, 120, 180, and 240 min after UVC irradiation. DNA repair rate (DRR) served as an indicator of DNA repair capacity. Results The results indicated that the maximum DNA damage (i.e. maximum tail length) in the UVC group mainly appeared at 90 min. The ranges of DRRs in the UVC group were 62.84%-98.71%. Average DRR value was 81.84%. The DRR difference between males and females was not significant (P<0.05). However, the average DRR value in the UVC plus NOV group and the UVC plus APC group was 52.98% and 39.57% respectively, which were significantly lower than that in the UVC group (P<0.01). Conclusion The comet assay is a rapid, simple and sensitive screening test to assess individual DNA repair (NER) capacity. It is suggested that the time to detect DNA single strand breaks in comet assay should include 0 (before UV irradiation), 90 and 240 min after exposure to 1.5 J·m-2 UVC at least. The DRR, as an indicator, can represent the individual DNA repair capacity in comet assay.展开更多
In order to improve the accuracy and reliability of ammonia(NH3)concentration prediction,which can provides a support to the ventilation control strategy,so as to reduce the impact of NH3 on the health and productivit...In order to improve the accuracy and reliability of ammonia(NH3)concentration prediction,which can provides a support to the ventilation control strategy,so as to reduce the impact of NH3 on the health and productivity of swine,this paper proposed an NH3 concentration prediction method based on Empirical Mode Decomposition(EMD)and Elman neural network modelling.The NH3 concentration and other four environmental parameters including temperature,humidity,carbon dioxide and light intensity were decomposed into several different time-scale intrinsic mode functions(IMFs).Then,the Elman neural network prediction model was used to predict each IMF.The predicted NH3 was obtained by reconstructing all the IMFs by EMD.The results show that for the proposed method,the determination coefficient between the predicted and real measured value is 0.9856,the Mean Absolute Error is 0.7088 ppm,the Root Mean Square Error is 0.9096 ppm,and the Mean Absolute Percentage Error is 0.41%.Compared with the Elman neural network,the proposed method has a good improvement in the accuracy,and provide effective parameters for the environmental monitoring of the swine house and the regulation of the NH3 concentration.展开更多
In the process of intelligent mine construction in open-pit mine, in order to improve the safety monitoring ability of mine transportation system, solve the problems of large human interference and blind Angle detecti...In the process of intelligent mine construction in open-pit mine, in order to improve the safety monitoring ability of mine transportation system, solve the problems of large human interference and blind Angle detection by existing conventional monitoring methods, this paper establishes an open-pit mine monitoring data set, and proposes a real-time intelligent monitoring model based on UAV. The reasoning component with strong computing power and low power consumption is selected, and the lightweight object detection model is selected for the experiment. A quantitative standard of dynamic energy consumption detection by evaluation algorithm is proposed. Through experimental comparison, it is found that YOLOv4-tiny has the highest comprehensive grade in detection accuracy, speed, energy consumption and other aspects, which is suitable for application in the above model.展开更多
基金supported by Vehicular Diesel Engine Development Program of China (Grant No. DEDP0202)
文摘Analytical method for the distributions of axial-load and stress is based on elastic assumption, but the threaded connections are often in plastic deformation stage in practice. Meanwhile the strain in the threaded connection is difficult to measure. So it is necessary to study the reliable numerical method. At present neither the convergence analysis of the computational results nor the elastic-plastic analysis in the loading-unloading process are studied. In this paper, von Mises plasticity and kinematic hardening model is used to describe the material response. A new convergence criterion for nonlinear finite element analysis of the loading-unloading process is proposed. An axisymmetric finite element model according to the proposed convergence criterion is developed and used to analyze the distributions of axial-load and stress. It can be conclude that the stress distribution analysis is more dependent on the mesh density than the axial-load distribution analysis. The stress distribution result indicates that with increasing of applied load, the engaged threads close to the nut-bearing surface become plastic firstly. The axial-load distribution result reveals that the load percentage carried by single thread depends on the position of thread and load intensity. When the load is relatively small, the applied load is mainly carried by the engaged threads near the nut-bearing surface, when the load is larger, the differences of percentages for all threads become small. The proposed convergence analyzing procedure is applicable for other nonlinear analyses. The obtained distributions of axial-load and stress can be a reference of engineering application.
基金the National Natural Science Foundation of China, No.39870879the Special Funds for Major State Basic Research of China,No.G 1998051103
文摘AIM: To investigate the anti-tumor mechanism of antisenseoligodeoxynucleotide cantide against hTERT.METHODS: Tumor cells were cultured overnight and grownto 50-60% confluence. HepG2 and SMMC-7721 were treatedwith cantide mixed with lipofectin, or lipofectin alone. Afterinducted for 6 h at 37℃, 10% FCS in DMEM was replacedin each well. After the treatment repeated twice to threetimes in each concentration of cantide, hTERT mRNA andprotein expression were measured by RT-PCR and Westernblot analysis, respectively. Telomerase aclivity was determinedby TRAP-ELISA assay. CPP32- and ICE-like activity was alsoinvestigated using CasPACE assay system at 48 h aftercantide treatment, and apoptosis was evaluated using theDeadEnd assay at 24, 48 and 72 h after cantide treatment.RESULTS: Compared to the control cells, the cells treated with cantide showed a dose-dependent decrease in hTERT mRNA levels at 24 h and in protein levels at 48 h respectively.The telomerase activity was decreased as the concentration of cantide increased at 48 h. At the concentration of 800 nM,the telomerase activity in the treated HepG2 and SMMC7721 cells was only 17.1% (P＜0.01) and 20.3% (P＜0.01)of that in untreated cells. The levels of CPP32-like protease activity in HepG2 and SMMC-7721 increased by 2.8- and 3.0-fold (P＜0.05) at 48 h, and the levels of ICE-like protease activity also increased by 2.6- and 3.2-fold (P＜0.05)respectively. The percentage of apoptosis in HepG2 and SMMC-7721 cells treated with 800 nM cantide at 72 h was 63% and 52% (P＜0.01), respectively. By contrast, 8%and 9% of the cells were apoptosis after 72 h treatment with lipofectin alone.CONCLUSION: Cantide can decrease telomerase activity by inhibiting the expression of hTERT gene and has a rapid anti-tumor effect through inducing the Caspase-dependent apoptosis. The rapid inhibitory effect of cantide on tumor growth demonstrates its feasibility in cancer treatment.
基金Supported by the National High Technology Research and Development Program of China (Grant No. 2002AA135360)the Key Program of the Education Depart-ment of Hunan Province (Grant No. 03C210)
文摘The correlations of isotopic ratios in precipitation with temperature, air pressure and humidity at dif- ferent altitudes, in southwest China, are analyzed. There appear marked negative correlations for the δ 18O in precipitation with precipitation amount, vapor pressure and atmospheric precipitable water (PW) at Mengzi, Simao and Tengchong stations on synoptic timescale; the marked negative correlations between the δ 18O in precipitation and the diurnal mean temperature at 400 hPa, 500 hPa, 700 hPa and 850 hPa are different from the temperature effect in middle-high-latitude inland. Moreover, the notable positive correlation between the δ 18O in precipitation and the dew-point deficit △Td at different altitudes is found at the three stations. On annual timescale, the annual precipitation amount weighted mean δ 18O display the negative correlations not only with annual precipitation but also with annual mean temperature at 500 hPa. It can be deduced that, in the years with abnormally strong summer monsoon, more warm and wet air from low-latitude oceans is transported northward along the vapor channel located in southwest China and generates abnormally strong rainfall on the way. Meanwhile, the ab- normally strong condensation process will release more condensed latent heat into atmosphere, and lead to the rise of atmospheric temperature during rainfall, but decline of the δ 18O in precipitation. On the contrary, in the years with abnormally weak summer monsoon, the abnormally weak condensation process will release less condensed latent heat into atmosphere, and lead to the decline of atmos- pheric temperature during rainfall, but increase of the δ 18O in precipitation.
基金financially supported by the Ministry of Science and Technology(Grant No.2016YFD0300905)the Natural Science Foundation of China(Grant No.31661143001).
文摘About 30 million hectares of rice are cultivated annually in China(FAOSTAT,2019).Because most rice fields are wellirrigated and suitable for fish living(‘fish’here refers to various aquatic animals like carps,prawns,crabs,soft shell turtles,etc.)(Fernando,1993),many efforts have been made to determine how well rice farming and aquaculture can be coupled as a rice-fish system(RFS),of which the same land and water produces both rice and aquatic products.With the technological guidance of RFSs and political supports from the Ministry of Agriculture and Rural Affairs of China since 2010(Supplemental Table 1),multiple types of large-scale,high-efficiency and technologically intensive RFSs are now being demonstrated in the main rice-growing areas of China(National Fisheries Technology Extension Centre,2019),and in total about 1.2 million hectares of rice fields are under RFSs.
基金Supported by the Ministry of Science and Technology of People's Republic of China National Eleventh Five-Year Research Program of China,the Applied Research of TCM Intervention Therapy to Refractory Acute Leukemia During the Peri-chemotherapy Period(No.2006BAI04A18)the Beijing Municipal Science&Technology Commission Ten Medications for Ten Diseases Project,Preclinical Study of Compound Zhebei Granules in Improving the Clinical Efficacy of Refractory Leukemia(No.Z151100003815027)Beijing University of Chinese Medicine Key Subject Program,Clinical and Basic Research of Hematological Diseases Using Chinese Medicine
文摘OBJECTIVE: To observe the effect of compound Zhebei granules(CZBG) with chemotherapy in the treatment of refractory acute leukemia.METHODS: In this multicenter, double-blind, placebo-controlled clinical trial, we used a central(online) randomization system to assign 235 patients to two treatment groups. A total of 118 patients received chemotherapy combined with CZBG(4 g,twice daily) and 117 patients received chemotherapy plus placebo. The clinical efficacy was evaluated at the end of one chemotherapeutic cycle.RESULTS: In the full analysis set, in which deaths due to disease progression were regarded as inefficacy, the rates of complete remission(CR) and partial remission(CR + PR) were 32.35% and 50.00%,respectively, for the chemotherapy combined with CZBG group, and 23.08% and 35.58%, respectively,for the chemotherapy plus placebo group. There was a statistically significant difference between the two groups according to a ysis set(PPχ2test(P < 0.05). In the per protocol analS), the CR(33.67%),CR+PR(52.04%) response rates for the chemotherapy plus CZBG group were significantly different from the response rates of the control group(CR:24.24% and CR+PR: 37.37%), respectively(P < 0.05).CONCLUSION: CZBG plus chemotherapy can improve the clinical remission rate of refractory acute leukemia after one just one therapeutic cycle.
基金This research is supported by the National Natural Science Foundation of China Grant(Nos.51705429&61801525)the Fundamental Research Funds for the Central Universities,Guangdong Natural Science Funds Grant(2018A030313400)+1 种基金Space Science and Technology Foundation,111 Project No.B13044UK Engineering and Physical Sciences Research Council(EPSRC)for support under grant EP/P018998/1,Newton Mobility Grant(IE161019)through Royal Society.
文摘Flexible,compact,lightweight and sustainable power sources are indispensable for modern wearable and personal electronics and small-unmanned aerial vehicles(UAVs).Hierarchical honeycomb has the unique merits of compact mesostructures,excellent energy absorption properties and considerable weight to strength ratios.Herein,a honeycomb-inspired triboelectric nanogenerator(h-TENG)is proposed for biomechanical and UAV morphing wing energy harvesting based on contact triboelectrification wavy surface of cellular honeycomb structure.The wavy surface comprises a multilayered thin film structure(combining polyethylene terephthalate,silver nanowires and fluorinated ethylene propylene)fabricated through high-temperature thermoplastic molding and wafer-level bonding process.With superior synchronization of large amounts of energy generation units with honeycomb cells,the manufactured h-TENG prototype produces the maximum instantaneous open-circuit voltage,short-circuit current and output power of 1207 V,68.5μA and 12.4 mW,respectively,corresponding to a remarkable peak power density of 0.275 mW cm^(−3)(or 2.48 mW g^(−1))under hand pressing excitations.Attributed to the excellent elastic property of self-rebounding honeycomb structure,the flexible and transparent h-TENG can be easily pressed,bent and integrated into shoes for real-time insole plantar pressure mapping.The lightweight and compact h-TENG is further installed into a morphing wing of small UAVs for efficiently converting the flapping energy of ailerons into electricity for the first time.This research demonstrates this new conceptualizing single h-TENG device’s versatility and viability for broad-range real-world application scenarios.
基金This research is financially supported by National Key Research and Development Program of China(2016YFD0700204-02)Research on Intelligent Non-contact Monitoring of Ruminating and Feeding Behavior of Dairy Cows,Heilongjiang Natural Science Foundation(LH2019C025)+4 种基金The“Young Talents”Project of Northeast Agricultural University(17QC19)China Postdoctoral Science Foundation(2017M611346)The Earmarked Fund for China Agriculture Research System(No.CARS-36)The University Nursing Program for Young Scholars with Creative Talents in Heilongjiang Province under Grant(UNPYSCT-2018143)The authors are grateful to anonymous reviewers for their comments.
文摘Ingestive-related behaviors including feeding and ruminating are important indexes to measure the health and welfare of dairy cows.The purpose of this study is to develop a method based on triaxial acceleration to automatically recognize feeding and ruminating of dairy cows.During the experiment,five diary cows raised in a barn were used as experimental subjects.A triaxial acceleration sensor was used as the device to collect jawmovement data of dairy cows,and the behaviors of dairy cows were classified into three categories:feeding,ruminating and other behavior.The features of time-domain and frequency-domain were extracted from the raw acceleration data.Three machine learning algorithms including k-nearest neighbor,support vector machine and probabilistic neural network were used for the classification and the results based on four different data segment lengths were compared.The results show that the three algorithms can be used for recognition of feeding and ruminating with high accuracy.Under the condition that the sampling frequency of the sensor is 5 Hz,the combination of data segment length of 256 and k-nearest neighbor algorithm is the best scheme for recognition of feeding and ruminating in this study.The precision and recall of recognition for feeding were 92.8%and 95.6%respectively,and those of recognition for ruminating were 93.7%and 94.3%respectively.The specificity and AUC of recognition for feeding were 96.1%and 0.959 respectively,and those of recognition for ruminating were 97.5%and 0.959 respectively.This will provide an effective method for real-time monitoring of ingestive-related behaviors of dairy cows and lay a foundation for prediction of dairy cows’health status and welfare to further achieve the purpose of disease prediction and adjusting feeding and management methods.
基金This research is supported by National Natural Science Foundation of China Grants(No.51705429&No.61801525)Science,Technology,and Innovation Commission of Shenzhen Municipality JCYJ20170815161054349+4 种基金Fundamental Research Funds for the Central Universities No.31020190503003National Natural Science Foundation of Shaanxi Province No.2018JQ5030Laboratory Fund of Science and Technology on Micro-system Laboratory No.614280401010417111 Project No.B13044a Guangdong Natural Science Funds Grant(2018A030313400).
文摘One of the critical issues for electret/triboelectric devices is the poor charge viability and stability in humid environments.Herein,we propose a new origami-inspired“W-tube”-shaped triboelectric nanogenerator(W-TENG)with two thin-film electrets folded based on Miura-origami.The Miura-origami fold is capable of transforming flat materials with large surface areas into reduced and compressed complex 3D structures with parallelogram tessellations.The triboelectric power generation components can thus be hermetically sealed inside the“W-tube”to avoid contact with the external humid environment.Furthermore,the elastic nature of the Miura-origami fold endows the proposed W-TENG device with excellent deformability,flexibility,and stretchability.Therefore,it is capable of harvesting kinetic energy from various directions and forms of movement,including horizontal pressing,vertical tapping,and lateral bending.The compact,light weight,and self-rebounding properties of the origami structure also make it convenient for integration into wearable devices.Various parameters of the W-TENG are intensively investigated,including the number of power generation units,original height of the device,acceleration magnitude,excitation direction,and water-proof capability.Triggered by hand tapping impulse excitation in the horizontal and vertical directions,the instantaneous open-circuit voltages can reach 791 V and 116 V with remarkable optimum powers of 691μW at 50MΩand 220μW at 35 MΩ,respectively.The outcomes of this work demonstrate the fusion of the ancient art of origami,material science,and energy conversion techniques to realize flexible,multifunctional,and water-proof TENG devices.
基金This study was supported by the funds from the Singapore Ministry of Education Academic Research Fund,Tier 1:RG111/15 and RG10/16 and Tier 2:MOE2016-T2-2 to 004.
文摘Electrochemical reduction of molecular O2 to hydrogen peroxide(H2O2)offers a promising solution for water purification and environmental remediation.Here,we design a hierarchical free-standing single-Co-atom(with Co-N4 coordination)electrode for oxygen reduction reaction(ORR)via a two-electron pathway to make H2O2 in acidic media.The current density of the single-Co-atom electrode reached 51 mA/cm2 at 0.1 V vs reversible hydrogen electrode,lasting for more than 10 hours of continuous operation with H2O2 selectivity greater than 80%.Toward practical application,the single-Co-atom electrode was directly used to assemble an electrochemical cell to produce H2O2 at a rate of 676 mol/kgcat/h with a cell voltage of about 1.6 V.
基金supported by the Ministry of Education of Singapore under Tier 1 RG115/18 and RG4/20,and Tier 2 T2EP10120-0009.
文摘Amorphous alloys,also known as metallic glasses,are solid metallic materials having long-range disordered atomic structures.Compared to crystalline alloys,amorphous alloys not only have metallic characters,but also possess several distinct properties associated to the amorphous structure,such as isotropy,composition flexibility,unsaturated surface,etc.As a result,amorphous alloys offer a class of highly promising materials for catalyzing electrochemical reactions.In this minireview,the preparation,characterization and electrocatalytic performances of a variety of metallic amorphous alloy materials are summarized.The influences of the amorphous alloy structure on different electrochemical reactions are discussed.Finally,a summary on the advantages and challenges of amorphous alloys in electrocatalysis is provided,along with some perspectives about the future research directions.
文摘The time series of accumulation in recent 300 years correlated well with solar activity in Dasuopu ice core. Results of spectrum analysis on the accumulation time series of the Dasuopu ice core shows that there are some periods that coincide with the periods of solar activity. By comparing the long-time change trend of the accumulation in the Dasuopu ice core with various kinds of indexes of solar activity intensity, a negative correlation is found between the trend and solar activity.
基金supported by the Open Foundation of State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University (No.200906)the Natural Science Foundation of Jiangxi Province (No.2010GZH0048)+1 种基金the National Natural Science Foundation of China (No. 21067004)the Young Science Foundation of Jiangxi Province Education Office (No. GJJ10150)
文摘Nano-sized γ-alumina （γ-Al2O3） was first prepared by a precipitation method. Then, active component of cobalt and a series of alkaline- earth metal promoters or nickel （Ni） with different contents were loaded on the γ-Al2O3 support. The catalysts were characterized by N2 adsorption-desorption, X-ray diffraction （XRD） and thermogravimetry analysis （TGA）. The activity and selectivity of the catalysts in catalytic partial oxidation （CPO） of methane have been compared with Co/γ-Al2O3, and it is found that the catalytic activity, selectivity, and stability are enhanced by the addition of alkaline-earth metals and nickel. The optimal loadings of strontium （Sr） and Ni were 6 and 4 wt%, respectively. This finding will be helpful in designing the trimetallic Co-Ni-Sr/γ-Al2O3 catalysts with high performance in CPO of methane
基金This work was supported by the grant from the National Key Research and Development Program of China under Grant 2016YFD0700204-02the Earmarked Fund for China Agricul-ture Research System under Grant CARS-35+2 种基金the"Young Talents"Project of Northeast Agricultural University under Grant 17QC20the University Nursing Program for Young Scholars with Creative Talents in Heilongjiang Province under Grant UNPYSCT-2020092 and UNPYSCT-2018142and the Hei-longjiang Post-doctoral Subsidy Project of China under Grant LBH-Z17020.
文摘Coughing is an obvious respiratory disease symptom,which affects the airways and lungs of pigs.In pig houses,continuous online monitoring of cough sounds can be used to build an intelligent alarm system for disease early detection.Owing to complicated interferences in piggery,recognition of pig cough sound becomes difficult.Although a lot of algorithms have been proposed to recognize the pig cough sounds,the recognition accuracy in field sit-uations still needs enhancement.The purpose of this research is to provide a highly accu-rate pig cough recognition method for the respiratory disease alarm system.We propose a classification algorithm based on the fine-tuned AlexNet model and feature of the spectro-gram.With the advantages of the convolutional neural network in image recognition,the sound signals are converted into spectrogram images for recognition,to enhance the accu-racy.We compare the proposed algorithm’s performance with the probabilistic neural net-work classifier and some existing algorithms.The results reveal that the proposed algorithm significantly outperforms the other algorithms-cough and overall recognition accuracies reach to 96.8%and 95.4%,respectively,with 96.2%F1-score achieved.
基金This work is sponsored by the Natural Science Foundation of Heilongjiang Province of China under Grant No.LC2016024Natural Science Foundation of the Jiangsu Higher Education Institutions Grant No.17KJB520044Six Talent Peaks Project in Jiangsu Province No.XYDXX-108.
文摘As an extension of the traditional encryption technology,information hiding has been increasingly used in the fields of communication and network media,and the covert communication technology has gradually developed.The blockchain technology that has emerged in recent years has the characteristics of decentralization and tamper resistance,which can effectively alleviate the disadvantages and problems of traditional covert communication.However,its combination with covert communication thus far has been mostly at the theoretical level.The BLOCCE method,as an early result of the combination of blockchain and covert communication technology,has the problems of low information embedding efficiency,the use of too many Bitcoin addresses,low communication efficiency,and high costs.The present research improved on this method,designed the V-BLOCCE which uses base58 to encrypt the plaintext and reuses the addresses generated by Vanitygen multiple times to embed information.This greatly improves the efficiency of information embedding and decreases the number of Bitcoin addresses used.Under the premise of ensuring the order,the Bitcoin transaction OP_RETURN field is used to store the information required to restore the plaintext and the transactions are issued at the same time to improve the information transmission efficiency.Thus,a more efficient and feasible method for the application of covert communication on the blockchain is proposed.In addition,this paper also provides a more feasible scheme and theoretical support for covert communication in blockchain.
文摘Objective Alkaline comet assay was used to evaluate DNA repair (nucleotide excision repair, NER) capacity of human fresh lymphocytes from 12 young healthy non-smokers (6 males and 6 females). Methods Lymphocytes were exposed to UV-C (254 nm) at the dose rate of 1.5 J/m2/sec. Novobiocin (NOV) and aphidicolin (APC), DNA repair inhibitors, were utilized to imitate the deficiency of DNA repair capacity at the incision and ligation steps of NER. Lymphocytes from each donor were divided into three grougs: UVC group, UVC plus NOV group, and UVC plus APC group. DNA single strand breaks were detected in UVC irradiated cells incubated for 0, 30, 60, 90, 120, 180, and 240 min after UVC irradiation. DNA repair rate (DRR) served as an indicator of DNA repair capacity. Results The results indicated that the maximum DNA damage (i.e. maximum tail length) in the UVC group mainly appeared at 90 min. The ranges of DRRs in the UVC group were 62.84%-98.71%. Average DRR value was 81.84%. The DRR difference between males and females was not significant (P<0.05). However, the average DRR value in the UVC plus NOV group and the UVC plus APC group was 52.98% and 39.57% respectively, which were significantly lower than that in the UVC group (P<0.01). Conclusion The comet assay is a rapid, simple and sensitive screening test to assess individual DNA repair (NER) capacity. It is suggested that the time to detect DNA single strand breaks in comet assay should include 0 (before UV irradiation), 90 and 240 min after exposure to 1.5 J·m-2 UVC at least. The DRR, as an indicator, can represent the individual DNA repair capacity in comet assay.
基金This research is financially supported by National Key Research and Development Program of China(2016YFD0700204-02)The“Young Talents”Project of Northeast Agricultural University(17QC20)+1 种基金Research on Attitude Fusion Zero Offset Correction and Decoupling Noise Reduction for Non-flat Production Flow Sensors,China Postdoctoral Fund(2016M601406)Central Guide to Local Science and Technology Development(ZY17C06)and The Earmarked Fund for China Agriculture Research System(No.CARS-35).The authors are grateful to anonymous reviewers for their comments.
文摘In order to improve the accuracy and reliability of ammonia(NH3)concentration prediction,which can provides a support to the ventilation control strategy,so as to reduce the impact of NH3 on the health and productivity of swine,this paper proposed an NH3 concentration prediction method based on Empirical Mode Decomposition(EMD)and Elman neural network modelling.The NH3 concentration and other four environmental parameters including temperature,humidity,carbon dioxide and light intensity were decomposed into several different time-scale intrinsic mode functions(IMFs).Then,the Elman neural network prediction model was used to predict each IMF.The predicted NH3 was obtained by reconstructing all the IMFs by EMD.The results show that for the proposed method,the determination coefficient between the predicted and real measured value is 0.9856,the Mean Absolute Error is 0.7088 ppm,the Root Mean Square Error is 0.9096 ppm,and the Mean Absolute Percentage Error is 0.41%.Compared with the Elman neural network,the proposed method has a good improvement in the accuracy,and provide effective parameters for the environmental monitoring of the swine house and the regulation of the NH3 concentration.
文摘In the process of intelligent mine construction in open-pit mine, in order to improve the safety monitoring ability of mine transportation system, solve the problems of large human interference and blind Angle detection by existing conventional monitoring methods, this paper establishes an open-pit mine monitoring data set, and proposes a real-time intelligent monitoring model based on UAV. The reasoning component with strong computing power and low power consumption is selected, and the lightweight object detection model is selected for the experiment. A quantitative standard of dynamic energy consumption detection by evaluation algorithm is proposed. Through experimental comparison, it is found that YOLOv4-tiny has the highest comprehensive grade in detection accuracy, speed, energy consumption and other aspects, which is suitable for application in the above model.
