The efficient separation and collection of ammonia(NH_(3))during NH_(3) synthesis process is essential to improve the economic efficiency and protect the environment.In this work,ethanolammonium hydrochloride(EtOHACl)...The efficient separation and collection of ammonia(NH_(3))during NH_(3) synthesis process is essential to improve the economic efficiency and protect the environment.In this work,ethanolammonium hydrochloride(EtOHACl)and phenol(PhOH)were used to prepare a novel class of deep eutectic solvents(DESs)with multiple active sites and low viscosities.The NH_(3) separation performance of EtOHACl+PhOH DESs was analyzed completely.It is figured out that the NH_(3) absorption rates in EtOHACl+PhOH DESs are very fast.The NH_(3) absorption capacities are very high and reach up to 5.52 and 10.74 mol·kg1 at 11.2 and 100.4 kPa under 298.2 K,respectively.In addition,the EtOHACl+PhOH DESs present highly selective absorption of NH_(3) over N_(2) and H_(2) and good regenerative properties after seven cycles of absorption/desorption.The intrinsic separation mechanism of NH_(3) by EtOHACl+PhOH DESs was further revealed by spectroscopic analysis and quantum chemistry calculations.展开更多
The active ingredients of Camellia japonica flowers(CJF)at high and low altitudes,as well as their skin care efficacy were compared.The dried red CJF at high and low altitudes were ultrasonically extracted with 70%eth...The active ingredients of Camellia japonica flowers(CJF)at high and low altitudes,as well as their skin care efficacy were compared.The dried red CJF at high and low altitudes were ultrasonically extracted with 70%ethanol,and these extracts were concentrated and then diluted to a constant volume.The content of total flavonoids,total polyphenols and total proteins was tested and analyzed.In addition,DPPH free radical scavenging,inhibition of the formation of advanced glycation end products,and inhibitory activity against elastase was measured to compare their skin care efficacy in anti-oxidation,anti-glycation,anti-wrinkling and firming.The results showed that,based on the dry weight of CJF,the content of total flavonoids and total proteins of the CJF at high altitude was approximately 1.5 times of the CJF at low altitude,while the content of total polyphenols was approximately 2.4 times that of the CJF at low altitude.The skin care efficacy of CJF at high altitude was significantly better than that of the CJF at low altitude.This work could provide theoretical basis for the selection and application of Camellia japonica flowers in the field of cosmetics.展开更多
Based on our previous work, the winter sea surface temperature(SST) in the Kuroshio Extension(KE) region showed significant variability over the past century with periods of ~6 a between 1930 and 1950 and ~10 a be...Based on our previous work, the winter sea surface temperature(SST) in the Kuroshio Extension(KE) region showed significant variability over the past century with periods of ~6 a between 1930 and 1950 and ~10 a between1980 and 2009. How the activity of the Aleutian Low(AL) induces this dual-period variability over the two different timespans is further investigated here. For the ~6 a periodicity during 1930–1950, negative wind stress curl(WSC)anomalies in the central subtropical Pacific associated with an intensified AL generate positive sea surface height(SSH) anomalies. When these wind-induced SSH anomalies propagate westwards to the east of Taiwan, China two years later, positive velocity anomalies appear around the Kuroshio to the east of Taiwan and then the mean advection via this current of velocity anomalies leads to a strengthened KE jet and thus an increase in the KE SST one year later. For the ~10 a periodicity during 1980–2009, a negative North Pacific Oscillation-like dipole takes2–3 a to develop into a significant positive North Pacific Oscillation-like dipole, and this process corresponds to the northward shift of the AL. Negative WSC anomalies associated with this AL activity in the central North Pacific are able to induce the positive SSH anomalies. These oceanic signals then propagate westward into the KE region after 2–3 a, favoring a northward shift of the KE jet, thus leading to the warming of the KE SST. The feedbacks of the KE SST anomaly on the AL forcing are both negative for these two periodicities. These results suggest that the dual-period KE SST variability can be generated by the two-way KE-SST-AL coupling.展开更多
Purpose: The purpose of this study was to evaluate the effect of using a passive exoskeleton on lumbar muscle activity during lifting movements, and to determine whether muscle activity remains altered after exoskelet...Purpose: The purpose of this study was to evaluate the effect of using a passive exoskeleton on lumbar muscle activity during lifting movements, and to determine whether muscle activity remains altered after exoskeleton removal. This study sought to identify the potential risks and benefits associated with the use of passive exoskeletons for the prevention and treatment of low back pain. Methods: Eighteen healthy adult participants lifted a 10 kg suitcase while wearing a passive exoskeleton. Muscle activity and postures were measured during lifting and before, during, and after exoskeleton use. This study examined whether the reduced muscle activity observed during exoskeleton use persisted after exoskeleton removal. Muscle activity was assessed using electromyography and postures were recorded using reflective markers and a camera. Results: The study found that Lumbar muscle activity decreased significantly (approximately 40%) during exoskeleton use compared to that without exoskeleton use. Importantly, lumbar muscle activity remained low after exoskeleton removal, at levels similar to those observed during exoskeleton use. This suggests that individuals adapted to the exoskeleton support and maintained altered muscle control, even without the exoskeleton. Conclusion: This study demonstrates that passive exoskeletons significantly reduce lumbar muscle activity during lifting tasks, and that this altered muscle control persists after exoskeleton removal. These findings contribute to the understanding of the risks and benefits of passive exoskeletons, potentially aiding their development and informing their use in the prevention and treatment of low back pain.展开更多
Activity recognition of indoor occupants using indirect sensing with less privacy violation is one of the hot research topics. This paper proposes a CO<sub>2</sub> sensor-based indoor occupant activity mon...Activity recognition of indoor occupants using indirect sensing with less privacy violation is one of the hot research topics. This paper proposes a CO<sub>2</sub> sensor-based indoor occupant activity monitoring system. Using the IoT sensor node that contains CO<sub>2</sub> sensors, the measured CO<sub>2</sub> concentrations in three locations (laboratory, office, and bedroom) were stored in a cloud server for up to 35 days starting July 1, 2023. The CO<sub>2</sub> measurements stored at 30-second intervals were statistically processed to produce a heat-mapped display of the hourly average or maximum CO<sub>2</sub> concentration. From the heatmap visualizations of CO<sub>2</sub> concentration, the proposed system estimated meeting, heating water using a portable stove, and sleep for the occupants’ activity recognition.展开更多
Heparin has been used as an anticoagulant drug for many years, but it has significant side ef fects. In the search for good substitutes, low molecular weight(MW) polysaccharides from S argassum fusiforme have been exa...Heparin has been used as an anticoagulant drug for many years, but it has significant side ef fects. In the search for good substitutes, low molecular weight(MW) polysaccharides from S argassum fusiforme have been examined and confi rmed to possess biological activities. Here, S. fusiforme polysaccharides(SFP) were extracted and subjected to a hydrogen peroxide(H_2O_2) oxidation method for the preparation of low-MW SFP(LSFP). The effects of temperature, pH, and H_2O_2 concentration on the degradation process were also examined. Several LSFP of 36, 9, 5.7, and 2.7 kDa were obtained under different conditions, and their anticoagulant activities studied in vitro. The results showed that SFP and LSFP prolonged activated partial thromboplastin(APTT), prothrombin(PT) and thrombin times(TT) significantly, indicating that these low MW polysaccharides possessed anticoagulant activity in the intrinsic, extrinsic, and common coagulation pathways. As these ef fects were related to the MW of the polysaccharides in APTT and TT but not in PT, the contents of the monosaccharide fucose and sulfate and the polysaccharide MW could have exerted combined ef fects. The details of this mechanism require further verifi cation.展开更多
Sunflower seed meal peptide as one sort of bioactive peptide has intensively application prospects. However, preparation of low salt peptide from sunflower seed meal with high efficiency remains a challenge. In this s...Sunflower seed meal peptide as one sort of bioactive peptide has intensively application prospects. However, preparation of low salt peptide from sunflower seed meal with high efficiency remains a challenge. In this study, single and compound proteases were optimized to hydrolyze protein. Results showed that hydrolysis at pH 7.0 by proteases resulted in ash content in the range of 5.66%-7.37% and small peptides. Among all hydrolysis processes, sequential hydrolysis of Alcalase with Flavourzyme and Alcalase with Protamex showed higher nitrogen recovery ratio (67.66% and 66.49%, respectively). Furthermore, biological activities of peptides were investigated by testing their ABTS (2,2-azinobis (3-ethylben-zothiazoline-6-sulfonic acid) diammonium salt) radical scavenging activity, DPPH (2,2-diphenyl-1-picrylhydrazil) radical scavenging activity and angiotensin converting enzyme (ACE) inhibitory activity. Peptide hydrolyzed by Alcalase with Papain presented the highest antioxidant activity, followed by Alcalase with Protamex, with ABTS scavenging rate as 63.01% and 31.75%, and DPPH scavenging rate as 56.04% and 28.06%, respectively. Synchronously, peptide hydrolyzed by Alcalase with Protamex and Alcalase with Alcalase had the highest ACE inhibitory activity (56.74%, 56.76%). In conclusion, hydrolysis by proteases Alcalase with Protamex at pH 7.0 was the most effective method for the preparation of low salt peptide from sunflower seed meal, which could be an alternative for anti-oxidants and anti-vasoconstrictor.展开更多
Zinc deficiency is one of the most widespreadmicro-nutritional disorder for rice. To solve the problem, screening Zn-efficient cultivars isan available method and understanding geno-
The polyoxometalate(POM)-imidazole ionic liquid(IL) [C8mim]2[Mo6O19](C8mim=1-methyl-3-octylimi- dazolium) with a low melting point of 82.6 °C was successfully prepared and characterized by FTIR, XPS, NMR, T...The polyoxometalate(POM)-imidazole ionic liquid(IL) [C8mim]2[Mo6O19](C8mim=1-methyl-3-octylimi- dazolium) with a low melting point of 82.6 °C was successfully prepared and characterized by FTIR, XPS, NMR, TG and so on. The polyoxomolybdate-based IL has high stability, and its decomposing temperature reaches 321 °C, which is higher than that of 1-alkyl-3-methylimidazolium halides IL. Further photocatalytic performances of the IL were measured via degrading dye rhodamine B(RB) in aqueous solution under the UV light irradiation. The experiments show that the conversion of RB reaches 80.5% after 90 min under UV-light and the degradation efficiency depends on the pH value of the solution, irradiation time and the dosage of the IL and so on.展开更多
This work was supported by the National Natural Science Foundation of China (No. 3870902). Objective: To determine the NK activity of lymphocyte subsets and the effects of low dose radiation. Methods: Lymphocyte s...This work was supported by the National Natural Science Foundation of China (No. 3870902). Objective: To determine the NK activity of lymphocyte subsets and the effects of low dose radiation. Methods: Lymphocyte subsets were separated by monoclonal antibodies. The NK activity of each subset on tumor cells was detected by radioactive release method. Results: The results showed that besides NK cells, CD 4, CD 8 and B cells alone can kill tumor cells. But the cellkilling activity of NK cells appeared to be strongest. There was synergistic effect between CD 4 and NK cells. The activity of mixed lymphocytes was more than that of only one subset. The effect of low dose radiation (LDR) on NK activity of panlymphocytes or NK cells was different. Conclusion: This paper demonstrated that NK activity of mononuclear cells was called “NK activity of lymphocytes”, but it is not true. Only when NK cells were separated by monoclonal antibodies, its killer activity can be called “activity of NK cells”.展开更多
Neuronal ensemble activity codes working memory.In this work,we developed a neuronal ensemble sparse coding method,which can effectively reduce the dimension of the neuronal activity and express neural coding.Multicha...Neuronal ensemble activity codes working memory.In this work,we developed a neuronal ensemble sparse coding method,which can effectively reduce the dimension of the neuronal activity and express neural coding.Multichannel spike trains were recorded in rat prefrontal cortex during a work memory task in Y-maze.As discretesignals,spikes were transferred into cont inuous signals by estinating entropy.Then the normalized continuous signals were decomposed via non-negative sparse met hod.The non-negative components were extracted to reconstruct a low-dimensional ensemble,while none of the feature components were missed.The results showed that,for well-trained rats,neuronal ensemble activities in the prefrontal cortex changed dynamically during the.working memory task.And the neuronal ensemble is more explicit via using non-negative sparse coding.Our results indicate that the neuronal ensemblesparse coding method can effectively reduce the dimnension of neuronal activity and it is a useful tool to express neural coding.展开更多
After defining landslide and debris flow, human activity, and precipitation indices, using with landslide and debris flow disaster data in low-latitude plateau of China, reflecting human activity and precipitation dat...After defining landslide and debris flow, human activity, and precipitation indices, using with landslide and debris flow disaster data in low-latitude plateau of China, reflecting human activity and precipitation data, the influence of human activity and precipitation on mid-long term evolution of landslide and debris flow was studied with the wavelet technique. Results indicate that mid-long evolution of landslide and debris flow disaster trends to increase 0.9 unit every year, and presents obvious stage feature. The abrupt point from rare to frequent periods took place in 1993. There is significant in-phase resonance oscillation between human activity and landslide and debris flow frequency on a scale of 11-16 years, in which the variation of human activity occurs about 0.2-2.8 years before landslide and debris flow variation. Thus, the increase of landslide and debris flow frequency in low latitude plateau of China may be mainly caused by geo-environmental degradation induced by human activity. After the impact of human activity is removed, there is sig- nificant in-phase resonance oscillation between landslide and debris flow frequency and summer rainfall in low-latitude plateau of China in quasi-three-year and quasi-six-year scales, in which the variation of summer precipitation occurs about 0.0-0.8 years before landslide and debris flow variation. Summer precipitation is one of important external causes which impacts landslide and debris flow frequency in low-latitude plateau of China. The mid-long term evolution predicting model of landslide and debris flow disasters frequency in low-latitude plateau region with better fitting and predicting ability was built by considering human activity and summer rainfall.展开更多
Low-fi'equency vertical vibration isolation systems play important roles in precision measurements to reduce seismic and environmental vibration noise. Several types of active vibration isolation systems have been de...Low-fi'equency vertical vibration isolation systems play important roles in precision measurements to reduce seismic and environmental vibration noise. Several types of active vibration isolation systems have been developed. However, few researches focus on how to optimize the test mass install position in order to improve the vibration transmissibility. An active low-frequency vertical vibration isolation system based on an earlier instrument, the Super Spring, is designed and implemented. The system, which is simple and compact, consists of two stages: a parallelogram-shaped linkage to ensure vertical motion, and a simple spring-mass system. The theoretical analysis of the vibration isolation system is presented, including terms erroneously ignored before. By carefully choosing the mechanical parameters according to the above analysis and using feedback control, the resonance frequency of the system is reduced from 2.3 to 0.03 Hz, a reduction by a factor of more than 75. The vibration isolation system is installed as an inertial reference in an absolute gravimeter, where it improved the scatter of the absolute gravity values by a factor of 5. The experimental results verifies the improved performance of the isolation system, making it particularly suitable for precision experiments. The improved vertical vibration isolation system can be used as a prototype for designing high-performance active vertical isolation systems. An improved theoretical model of this active vibration isolation system with beam-pivot configuration is proposed, providing fundamental guidelines for vibration isolator design and assembling.展开更多
As reported in this paper, a strain of oil-degrading bacterium Sp - 5 - 3 was determined to belong to Enterobacteriaceae, which would be useful for microbial enhanced oil recovery (MEOR). The aim of our study was to g...As reported in this paper, a strain of oil-degrading bacterium Sp - 5 - 3 was determined to belong to Enterobacteriaceae, which would be useful for microbial enhanced oil recovery (MEOR). The aim of our study was to generate a mutant using low energy N+ beam implantation. With 10 keV of energy and 5.2× 1014 N+/cm2 of dose - the optimum condition, a mutant, S-34, was obtained, which had nearly a 5-fold higher surface and a 13-fold higher of emulsifica-tion activity than the wild type. The surface activity was measured by two methods, namely, a surface tension measuring instrument and a recording of the repulsive circle of the oil film; the emulsification activity was scaled through measuring the separating time of the oil-fermentation mixture. The metabolic acid was determined as methane by means of gas chromatography.展开更多
In recent decades,while the incidence of thyroid cancer has increased exponentially around the world,mortality has remained stable.The vast majority of this increase is attributable to the identification of intrathyro...In recent decades,while the incidence of thyroid cancer has increased exponentially around the world,mortality has remained stable.The vast majority of this increase is attributable to the identification of intrathyroidal papillary microcarcinomas,which exhibit slow growth rates with indolent courses.A diagnosis of thyroid cancer based upon the presence of these small tumors could be considered as an overdiagnosis,as the majority of these tumors would not likely result in death if left untreated.Although surgical resection was the classical standard therapy for papillary microcarcinomas,active surveillance(AS)has emerged over the last three decades as an alternative approach that is aimed to recognize a minority group of patients who will clinically progress and would likely benefit from rescue surgery.Despite the encouraging results of AS,its implementation in clinical practice is strongly influenced by psychosocial factors.The aim of this review is to describe the epidemiology,clinical evolution,prognostic factors,and mortality of papillary thyroid microcarcinomas.We also summarize the AS strategy according to published evidence,characterize the criteria for selecting patients for AS according to risk factors and environmental characteristics,as well as analyze the current limitations for AS implementation.展开更多
The effect of ultrasonic cavitations on the activity of vanadium catalysts atlow temperatures for the oxidation of sulfur dioxide, in which refined carbonized mother liquor hadbeen added, was investigated. Twenty minu...The effect of ultrasonic cavitations on the activity of vanadium catalysts atlow temperatures for the oxidation of sulfur dioxide, in which refined carbonized mother liquor hadbeen added, was investigated. Twenty minutes were needed to produce obvious cavitations when thecatalyst raw material was treated in the 50 W ultrasonic generator. However, only 10 minutes wouldbe needed in a 150 W ultrasonic generator. The higher the temperature of the wet material, the lesstime was needed to produce cavitations, and the optimal temperature was 60℃. The water content inthe wet material mainly affected the quantity of cavitations. Ls-8 catalyst was prepared usingultrasonic. Its activity for conversion of SO_2 reached to 52.5% at 410℃ and 4.2% at 350℃. Thedifferential thermal analyses indicate that both endothermic peaks and exothermic peaks noticeablyshifted forward compared with Ls catalyst prepared without ultrasonic, and SEM results show auniform pore size distribution for Ls-8 catalyst.展开更多
Aiming at providing with high-load capability in active vibration control of large-scale rotor system, a new type of active actuator to simultaneously reduce the dangers of low frequency flexural and torsional vibrati...Aiming at providing with high-load capability in active vibration control of large-scale rotor system, a new type of active actuator to simultaneously reduce the dangers of low frequency flexural and torsional vibrations is designed. The actuator employs electro-hydraulic system and can provide a high and circumferential load. To initialize new research, the characteristics of various kinds of active actuators to control rotor shaft vibration are briefly introduced. The purpose of this paper is to introduce the preliminary results via presenting the structure, functions and operating principles, in particular, the working process of the electro-hydraulic system of the new actuator which includes a set of high speed electromagnetic valves and a series of sloping cone-shaped openings, and presenting the transmission relationships among the control parameters from control signals into the valves to active load onto shaft. The course of the work is dynamic, and a series of spatial forces and moments are put on the shaft to get an external resultant force to reduce excitations that induce vibration of shafts. By checking states of vibration, the actuator can control the impulse width and the interval of injection time for applying different control force to a vibration shaft in two circumference directions through the regulating action of a set of combination directional control valves. The results from simulating analysis and experiment show evidence of that this design can satisfy the case of active process of decreasing of flexural and torsional vibrations.展开更多
Radio frequency plasma was used to prepare a vanadium catalyst. The resultsshowed that activating time of the catalyst could be shortened quickly and the catalytic activitywas improved to some extent with the use of p...Radio frequency plasma was used to prepare a vanadium catalyst. The resultsshowed that activating time of the catalyst could be shortened quickly and the catalytic activitywas improved to some extent with the use of plasma. Catalyst Ls-9 was prepared under an optimalcondition of 40 W discharge power, 10 min discharge time and 8 Pa gas pressure. The catalyticactivity was up to 54.7% at 410℃, which was 2.2% higher than that of the Ls-8 catalyst. Only 10 minwas needed to activate the catalyst with plasma, which was 1/9 of the traditional calcination time.For Ls-9, both the endothermic as well as the exothermic peaks detected by differential thermalanalysis shifted to higher temperatures obviously, indicating that its crystal phase could melteasily. There existed an apparent endothermic peak at 283℃. SEM photographs showed a uniform sizedistribution. It is inferred that the quadrivalent vanadium compound may exist mainly in the form ofVOSO_4.展开更多
基金supported by the National Natural Science Foundation of China(22221005 and 22008033).
文摘The efficient separation and collection of ammonia(NH_(3))during NH_(3) synthesis process is essential to improve the economic efficiency and protect the environment.In this work,ethanolammonium hydrochloride(EtOHACl)and phenol(PhOH)were used to prepare a novel class of deep eutectic solvents(DESs)with multiple active sites and low viscosities.The NH_(3) separation performance of EtOHACl+PhOH DESs was analyzed completely.It is figured out that the NH_(3) absorption rates in EtOHACl+PhOH DESs are very fast.The NH_(3) absorption capacities are very high and reach up to 5.52 and 10.74 mol·kg1 at 11.2 and 100.4 kPa under 298.2 K,respectively.In addition,the EtOHACl+PhOH DESs present highly selective absorption of NH_(3) over N_(2) and H_(2) and good regenerative properties after seven cycles of absorption/desorption.The intrinsic separation mechanism of NH_(3) by EtOHACl+PhOH DESs was further revealed by spectroscopic analysis and quantum chemistry calculations.
文摘The active ingredients of Camellia japonica flowers(CJF)at high and low altitudes,as well as their skin care efficacy were compared.The dried red CJF at high and low altitudes were ultrasonically extracted with 70%ethanol,and these extracts were concentrated and then diluted to a constant volume.The content of total flavonoids,total polyphenols and total proteins was tested and analyzed.In addition,DPPH free radical scavenging,inhibition of the formation of advanced glycation end products,and inhibitory activity against elastase was measured to compare their skin care efficacy in anti-oxidation,anti-glycation,anti-wrinkling and firming.The results showed that,based on the dry weight of CJF,the content of total flavonoids and total proteins of the CJF at high altitude was approximately 1.5 times of the CJF at low altitude,while the content of total polyphenols was approximately 2.4 times that of the CJF at low altitude.The skin care efficacy of CJF at high altitude was significantly better than that of the CJF at low altitude.This work could provide theoretical basis for the selection and application of Camellia japonica flowers in the field of cosmetics.
基金The National Basic Research Program(973 Program) of China under contract No.2013CB956203the National Natural Science Foundation of China under contract No.41375063the Junior Fellowships for CAST Advanced Innovation Think-tank Program under contract No.DXB-ZKQN-2016-019
文摘Based on our previous work, the winter sea surface temperature(SST) in the Kuroshio Extension(KE) region showed significant variability over the past century with periods of ~6 a between 1930 and 1950 and ~10 a between1980 and 2009. How the activity of the Aleutian Low(AL) induces this dual-period variability over the two different timespans is further investigated here. For the ~6 a periodicity during 1930–1950, negative wind stress curl(WSC)anomalies in the central subtropical Pacific associated with an intensified AL generate positive sea surface height(SSH) anomalies. When these wind-induced SSH anomalies propagate westwards to the east of Taiwan, China two years later, positive velocity anomalies appear around the Kuroshio to the east of Taiwan and then the mean advection via this current of velocity anomalies leads to a strengthened KE jet and thus an increase in the KE SST one year later. For the ~10 a periodicity during 1980–2009, a negative North Pacific Oscillation-like dipole takes2–3 a to develop into a significant positive North Pacific Oscillation-like dipole, and this process corresponds to the northward shift of the AL. Negative WSC anomalies associated with this AL activity in the central North Pacific are able to induce the positive SSH anomalies. These oceanic signals then propagate westward into the KE region after 2–3 a, favoring a northward shift of the KE jet, thus leading to the warming of the KE SST. The feedbacks of the KE SST anomaly on the AL forcing are both negative for these two periodicities. These results suggest that the dual-period KE SST variability can be generated by the two-way KE-SST-AL coupling.
文摘Purpose: The purpose of this study was to evaluate the effect of using a passive exoskeleton on lumbar muscle activity during lifting movements, and to determine whether muscle activity remains altered after exoskeleton removal. This study sought to identify the potential risks and benefits associated with the use of passive exoskeletons for the prevention and treatment of low back pain. Methods: Eighteen healthy adult participants lifted a 10 kg suitcase while wearing a passive exoskeleton. Muscle activity and postures were measured during lifting and before, during, and after exoskeleton use. This study examined whether the reduced muscle activity observed during exoskeleton use persisted after exoskeleton removal. Muscle activity was assessed using electromyography and postures were recorded using reflective markers and a camera. Results: The study found that Lumbar muscle activity decreased significantly (approximately 40%) during exoskeleton use compared to that without exoskeleton use. Importantly, lumbar muscle activity remained low after exoskeleton removal, at levels similar to those observed during exoskeleton use. This suggests that individuals adapted to the exoskeleton support and maintained altered muscle control, even without the exoskeleton. Conclusion: This study demonstrates that passive exoskeletons significantly reduce lumbar muscle activity during lifting tasks, and that this altered muscle control persists after exoskeleton removal. These findings contribute to the understanding of the risks and benefits of passive exoskeletons, potentially aiding their development and informing their use in the prevention and treatment of low back pain.
文摘Activity recognition of indoor occupants using indirect sensing with less privacy violation is one of the hot research topics. This paper proposes a CO<sub>2</sub> sensor-based indoor occupant activity monitoring system. Using the IoT sensor node that contains CO<sub>2</sub> sensors, the measured CO<sub>2</sub> concentrations in three locations (laboratory, office, and bedroom) were stored in a cloud server for up to 35 days starting July 1, 2023. The CO<sub>2</sub> measurements stored at 30-second intervals were statistically processed to produce a heat-mapped display of the hourly average or maximum CO<sub>2</sub> concentration. From the heatmap visualizations of CO<sub>2</sub> concentration, the proposed system estimated meeting, heating water using a portable stove, and sleep for the occupants’ activity recognition.
基金Supported by the Ocean Public Welfare Scientifi c Research Project,State Oceanic Administration of the People’s Republic of China(No.201505033)the Qingdao People’s Livelihood Science and Technology Program(No.16-6-2-41-nsh)
文摘Heparin has been used as an anticoagulant drug for many years, but it has significant side ef fects. In the search for good substitutes, low molecular weight(MW) polysaccharides from S argassum fusiforme have been examined and confi rmed to possess biological activities. Here, S. fusiforme polysaccharides(SFP) were extracted and subjected to a hydrogen peroxide(H_2O_2) oxidation method for the preparation of low-MW SFP(LSFP). The effects of temperature, pH, and H_2O_2 concentration on the degradation process were also examined. Several LSFP of 36, 9, 5.7, and 2.7 kDa were obtained under different conditions, and their anticoagulant activities studied in vitro. The results showed that SFP and LSFP prolonged activated partial thromboplastin(APTT), prothrombin(PT) and thrombin times(TT) significantly, indicating that these low MW polysaccharides possessed anticoagulant activity in the intrinsic, extrinsic, and common coagulation pathways. As these ef fects were related to the MW of the polysaccharides in APTT and TT but not in PT, the contents of the monosaccharide fucose and sulfate and the polysaccharide MW could have exerted combined ef fects. The details of this mechanism require further verifi cation.
基金supports of the National Key R & D Program of China (2017YFD0400402)the National Natural Science Foundation of China (31501409)
文摘Sunflower seed meal peptide as one sort of bioactive peptide has intensively application prospects. However, preparation of low salt peptide from sunflower seed meal with high efficiency remains a challenge. In this study, single and compound proteases were optimized to hydrolyze protein. Results showed that hydrolysis at pH 7.0 by proteases resulted in ash content in the range of 5.66%-7.37% and small peptides. Among all hydrolysis processes, sequential hydrolysis of Alcalase with Flavourzyme and Alcalase with Protamex showed higher nitrogen recovery ratio (67.66% and 66.49%, respectively). Furthermore, biological activities of peptides were investigated by testing their ABTS (2,2-azinobis (3-ethylben-zothiazoline-6-sulfonic acid) diammonium salt) radical scavenging activity, DPPH (2,2-diphenyl-1-picrylhydrazil) radical scavenging activity and angiotensin converting enzyme (ACE) inhibitory activity. Peptide hydrolyzed by Alcalase with Papain presented the highest antioxidant activity, followed by Alcalase with Protamex, with ABTS scavenging rate as 63.01% and 31.75%, and DPPH scavenging rate as 56.04% and 28.06%, respectively. Synchronously, peptide hydrolyzed by Alcalase with Protamex and Alcalase with Alcalase had the highest ACE inhibitory activity (56.74%, 56.76%). In conclusion, hydrolysis by proteases Alcalase with Protamex at pH 7.0 was the most effective method for the preparation of low salt peptide from sunflower seed meal, which could be an alternative for anti-oxidants and anti-vasoconstrictor.
文摘Zinc deficiency is one of the most widespreadmicro-nutritional disorder for rice. To solve the problem, screening Zn-efficient cultivars isan available method and understanding geno-
基金Supported by the National Natural Science Foundation of China(Nos.2067101120731002+3 种基金20801004 10876002 20801005)the Specialized Research Fund for the Doctoral Program of Higher Education of China(No.200800070015).
文摘The polyoxometalate(POM)-imidazole ionic liquid(IL) [C8mim]2[Mo6O19](C8mim=1-methyl-3-octylimi- dazolium) with a low melting point of 82.6 °C was successfully prepared and characterized by FTIR, XPS, NMR, TG and so on. The polyoxomolybdate-based IL has high stability, and its decomposing temperature reaches 321 °C, which is higher than that of 1-alkyl-3-methylimidazolium halides IL. Further photocatalytic performances of the IL were measured via degrading dye rhodamine B(RB) in aqueous solution under the UV light irradiation. The experiments show that the conversion of RB reaches 80.5% after 90 min under UV-light and the degradation efficiency depends on the pH value of the solution, irradiation time and the dosage of the IL and so on.
文摘This work was supported by the National Natural Science Foundation of China (No. 3870902). Objective: To determine the NK activity of lymphocyte subsets and the effects of low dose radiation. Methods: Lymphocyte subsets were separated by monoclonal antibodies. The NK activity of each subset on tumor cells was detected by radioactive release method. Results: The results showed that besides NK cells, CD 4, CD 8 and B cells alone can kill tumor cells. But the cellkilling activity of NK cells appeared to be strongest. There was synergistic effect between CD 4 and NK cells. The activity of mixed lymphocytes was more than that of only one subset. The effect of low dose radiation (LDR) on NK activity of panlymphocytes or NK cells was different. Conclusion: This paper demonstrated that NK activity of mononuclear cells was called “NK activity of lymphocytes”, but it is not true. Only when NK cells were separated by monoclonal antibodies, its killer activity can be called “activity of NK cells”.
基金supported by the National Natural Science Foundation of China(No.61074131,91132722)the Doctoral Fund of the Ministry of Education of China(20101202110007).
文摘Neuronal ensemble activity codes working memory.In this work,we developed a neuronal ensemble sparse coding method,which can effectively reduce the dimension of the neuronal activity and express neural coding.Multichannel spike trains were recorded in rat prefrontal cortex during a work memory task in Y-maze.As discretesignals,spikes were transferred into cont inuous signals by estinating entropy.Then the normalized continuous signals were decomposed via non-negative sparse met hod.The non-negative components were extracted to reconstruct a low-dimensional ensemble,while none of the feature components were missed.The results showed that,for well-trained rats,neuronal ensemble activities in the prefrontal cortex changed dynamically during the.working memory task.And the neuronal ensemble is more explicit via using non-negative sparse coding.Our results indicate that the neuronal ensemblesparse coding method can effectively reduce the dimnension of neuronal activity and it is a useful tool to express neural coding.
基金supported by National Natural Science Foundation of China(Grant No.U0933603)National Science and Technology Sup-port Program(Grant No.2011BAC09B07)
文摘After defining landslide and debris flow, human activity, and precipitation indices, using with landslide and debris flow disaster data in low-latitude plateau of China, reflecting human activity and precipitation data, the influence of human activity and precipitation on mid-long term evolution of landslide and debris flow was studied with the wavelet technique. Results indicate that mid-long evolution of landslide and debris flow disaster trends to increase 0.9 unit every year, and presents obvious stage feature. The abrupt point from rare to frequent periods took place in 1993. There is significant in-phase resonance oscillation between human activity and landslide and debris flow frequency on a scale of 11-16 years, in which the variation of human activity occurs about 0.2-2.8 years before landslide and debris flow variation. Thus, the increase of landslide and debris flow frequency in low latitude plateau of China may be mainly caused by geo-environmental degradation induced by human activity. After the impact of human activity is removed, there is sig- nificant in-phase resonance oscillation between landslide and debris flow frequency and summer rainfall in low-latitude plateau of China in quasi-three-year and quasi-six-year scales, in which the variation of summer precipitation occurs about 0.0-0.8 years before landslide and debris flow variation. Summer precipitation is one of important external causes which impacts landslide and debris flow frequency in low-latitude plateau of China. The mid-long term evolution predicting model of landslide and debris flow disasters frequency in low-latitude plateau region with better fitting and predicting ability was built by considering human activity and summer rainfall.
基金Supported by Tsinghua University’s Scientific Research Initiative Program,China(Grant No.2010THZ05)
文摘Low-fi'equency vertical vibration isolation systems play important roles in precision measurements to reduce seismic and environmental vibration noise. Several types of active vibration isolation systems have been developed. However, few researches focus on how to optimize the test mass install position in order to improve the vibration transmissibility. An active low-frequency vertical vibration isolation system based on an earlier instrument, the Super Spring, is designed and implemented. The system, which is simple and compact, consists of two stages: a parallelogram-shaped linkage to ensure vertical motion, and a simple spring-mass system. The theoretical analysis of the vibration isolation system is presented, including terms erroneously ignored before. By carefully choosing the mechanical parameters according to the above analysis and using feedback control, the resonance frequency of the system is reduced from 2.3 to 0.03 Hz, a reduction by a factor of more than 75. The vibration isolation system is installed as an inertial reference in an absolute gravimeter, where it improved the scatter of the absolute gravity values by a factor of 5. The experimental results verifies the improved performance of the isolation system, making it particularly suitable for precision experiments. The improved vertical vibration isolation system can be used as a prototype for designing high-performance active vertical isolation systems. An improved theoretical model of this active vibration isolation system with beam-pivot configuration is proposed, providing fundamental guidelines for vibration isolator design and assembling.
基金The project supported by the Knowledge Innovation Project of the Chinese Academy of Sciences(No. KSCX2-SW-324)
文摘As reported in this paper, a strain of oil-degrading bacterium Sp - 5 - 3 was determined to belong to Enterobacteriaceae, which would be useful for microbial enhanced oil recovery (MEOR). The aim of our study was to generate a mutant using low energy N+ beam implantation. With 10 keV of energy and 5.2× 1014 N+/cm2 of dose - the optimum condition, a mutant, S-34, was obtained, which had nearly a 5-fold higher surface and a 13-fold higher of emulsifica-tion activity than the wild type. The surface activity was measured by two methods, namely, a surface tension measuring instrument and a recording of the repulsive circle of the oil film; the emulsification activity was scaled through measuring the separating time of the oil-fermentation mixture. The metabolic acid was determined as methane by means of gas chromatography.
文摘In recent decades,while the incidence of thyroid cancer has increased exponentially around the world,mortality has remained stable.The vast majority of this increase is attributable to the identification of intrathyroidal papillary microcarcinomas,which exhibit slow growth rates with indolent courses.A diagnosis of thyroid cancer based upon the presence of these small tumors could be considered as an overdiagnosis,as the majority of these tumors would not likely result in death if left untreated.Although surgical resection was the classical standard therapy for papillary microcarcinomas,active surveillance(AS)has emerged over the last three decades as an alternative approach that is aimed to recognize a minority group of patients who will clinically progress and would likely benefit from rescue surgery.Despite the encouraging results of AS,its implementation in clinical practice is strongly influenced by psychosocial factors.The aim of this review is to describe the epidemiology,clinical evolution,prognostic factors,and mortality of papillary thyroid microcarcinomas.We also summarize the AS strategy according to published evidence,characterize the criteria for selecting patients for AS according to risk factors and environmental characteristics,as well as analyze the current limitations for AS implementation.
基金Project(20176065)supported by the National Natural Science Foundation of China.
文摘The effect of ultrasonic cavitations on the activity of vanadium catalysts atlow temperatures for the oxidation of sulfur dioxide, in which refined carbonized mother liquor hadbeen added, was investigated. Twenty minutes were needed to produce obvious cavitations when thecatalyst raw material was treated in the 50 W ultrasonic generator. However, only 10 minutes wouldbe needed in a 150 W ultrasonic generator. The higher the temperature of the wet material, the lesstime was needed to produce cavitations, and the optimal temperature was 60℃. The water content inthe wet material mainly affected the quantity of cavitations. Ls-8 catalyst was prepared usingultrasonic. Its activity for conversion of SO_2 reached to 52.5% at 410℃ and 4.2% at 350℃. Thedifferential thermal analyses indicate that both endothermic peaks and exothermic peaks noticeablyshifted forward compared with Ls catalyst prepared without ultrasonic, and SEM results show auniform pore size distribution for Ls-8 catalyst.
基金supported by National Natural Science Foundation of China (No.50475112)National Hi-Tech Research and Development Program of China (863 Program,No.2006AA110112).
文摘Aiming at providing with high-load capability in active vibration control of large-scale rotor system, a new type of active actuator to simultaneously reduce the dangers of low frequency flexural and torsional vibrations is designed. The actuator employs electro-hydraulic system and can provide a high and circumferential load. To initialize new research, the characteristics of various kinds of active actuators to control rotor shaft vibration are briefly introduced. The purpose of this paper is to introduce the preliminary results via presenting the structure, functions and operating principles, in particular, the working process of the electro-hydraulic system of the new actuator which includes a set of high speed electromagnetic valves and a series of sloping cone-shaped openings, and presenting the transmission relationships among the control parameters from control signals into the valves to active load onto shaft. The course of the work is dynamic, and a series of spatial forces and moments are put on the shaft to get an external resultant force to reduce excitations that induce vibration of shafts. By checking states of vibration, the actuator can control the impulse width and the interval of injection time for applying different control force to a vibration shaft in two circumference directions through the regulating action of a set of combination directional control valves. The results from simulating analysis and experiment show evidence of that this design can satisfy the case of active process of decreasing of flexural and torsional vibrations.
基金The project is supported by the National Natural Science Foundation of China (No.20176065)
文摘Radio frequency plasma was used to prepare a vanadium catalyst. The resultsshowed that activating time of the catalyst could be shortened quickly and the catalytic activitywas improved to some extent with the use of plasma. Catalyst Ls-9 was prepared under an optimalcondition of 40 W discharge power, 10 min discharge time and 8 Pa gas pressure. The catalyticactivity was up to 54.7% at 410℃, which was 2.2% higher than that of the Ls-8 catalyst. Only 10 minwas needed to activate the catalyst with plasma, which was 1/9 of the traditional calcination time.For Ls-9, both the endothermic as well as the exothermic peaks detected by differential thermalanalysis shifted to higher temperatures obviously, indicating that its crystal phase could melteasily. There existed an apparent endothermic peak at 283℃. SEM photographs showed a uniform sizedistribution. It is inferred that the quadrivalent vanadium compound may exist mainly in the form ofVOSO_4.