OBJECTIVE:To study the effects of temperature on different facial areas by suspended moxibustion at two points,Zusanli(ST 36) and Hegu(LI 4),and probe the phenomena underlying self-regulation in the human body after t...OBJECTIVE:To study the effects of temperature on different facial areas by suspended moxibustion at two points,Zusanli(ST 36) and Hegu(LI 4),and probe the phenomena underlying self-regulation in the human body after thermal stimulation.METHODS:Thirty healthy volunteers accepted moxibustion over Zusanli(ST 36) and Hegu(LI 4),and the order of moxibustion points was randomly determined.Moxibustion method:suspension of moxibustion over Zusanli(ST 36) and Hegu(LI 4) on both sides was performed using an ignited moxa stick stuck in a support for 20 min.Observation method:An infrared thermal image of the face was taken before and after suspended moxibustion using a CK350 medical infrared thermal imaging instrument.Data analysis:A thermal microscopic section view system(TMTSys) was used to analyze the change in temperature in special facial areas.Statistical analysis was carried out using SPSS 14.0 software.RESULTS:Before moxibustion was suspended,the facial thermal image showed a T-shaped thermal area related to the vascular distribution with even temperature and good symmetry on both sides.Suspended moxibustion over Zusanli(ST 36) have a very significant increase in temperature at the forehead,around the nose,at the corners of the mouth,and at the cheeks and lips(P<0.01).Suspended moxibustion over Hegu(LI 4) also have a significant(P<0.05) increase in temperature around the nose,the corners of the mouth,the cheeks,and lips,where has a new high temperature area was formed(P<0.01).Suspended moxibustion over Hegu(LI 4) raised the temperature at the middle point of the lips more obviously than did Zusanli(ST 36) in the same person,(P<0.05).After 10 min of moxibustion over Zusanli(ST 36) and Hegu(LI 4),the change in temperature in the facial area reached its peak value.CONCLUSIONS:Facial infrared thermography of healthy people revealed a T-shaped thermal area reflecting a physiological thermal area.Moxibustion over Zusanli(ST 36) or Hegu(LI 4) raised the temperature in this facial T-shaped thermal area.Hegu(LI 4) led to the 展开更多
Subjects with Bell＇s palsy and healthy individuals were treated with moxibustion thermal stimulation on the Hegu （LI4） acupoint; an infrared thermal imaging system was used to observe facial-temperature changes. B...Subjects with Bell＇s palsy and healthy individuals were treated with moxibustion thermal stimulation on the Hegu （LI4） acupoint; an infrared thermal imaging system was used to observe facial-temperature changes. Bell＇s palsy patients developed low or high temperatures at the affected side, with poor symmetry. Healthy people showed high temperatures on the forehead, medial angle of the eye, nasal ala and around the lips, but low temperatures on bilateral cheeks, thus forming a ＂T-type hot area＂ in the face, with good temperature symmetry. Moxibustion treatment for 11 minutes significantly improved high asymmetry in temperature in the faces of Bell＇s palsy patients. This evidence indicates that moxibustion treatment on Hegu enables increases in facial temperatures in healthy people and Bell＇s palsy patients, especially around the lips. Moxibustion stimulation at the Hegu not only improves the global circulation but also has specific effects on the lips in Bell＇s palsy patients, but the underlying mechanism needs further investigation.展开更多
The recent development of tough tissue adhesives has stimulated intense interests among material scientists and medical doctors.However,these adhesives have seldom been tested in clinically demanding surgeries.Here we...The recent development of tough tissue adhesives has stimulated intense interests among material scientists and medical doctors.However,these adhesives have seldom been tested in clinically demanding surgeries.Here we demonstrate adhesive anastomosis in organ transplantation.Anastomosis is commonly conducted by dense sutures and takes a long time,during which all the vessels are occluded.Prolonged occlusion may damage organs and even cause death.We formulate a tough,biocompatible,bioabsorbable adhesive that can sustain tissue tension and pressurized flow.We expose the endothelial surface of vessels onto a gasket,press two endothelial surfaces to the adhesive using a pair of magnetic rings,and reopen the bloodstream immediately.The time for adhesive anastomosis is shortened compared to the time for sutured anastomosis.We have achieved adhesive anastomosis of a great vein in transplanting the liver of a pig.After the surgery,the adhesive is absorbed,the vein heals,and the pig lives for over one month.展开更多
The 2-m aperture Chinese Space Station Telescope(CSST),which observes at wavelengths ranging from 255 to 1000 nm,is expected to start science operations in 2024.An ultra-deep field observation program covering approxi...The 2-m aperture Chinese Space Station Telescope(CSST),which observes at wavelengths ranging from 255 to 1000 nm,is expected to start science operations in 2024.An ultra-deep field observation program covering approximately 10 deg2is proposed with supernovae(SNe) and other transients as one of its primary science drivers.This paper presents the simulated detection results of type Ⅰa supernovae(SNe Ⅰa) and explores the impact of new datasets on the determinations of cosmological parameters.The simulated observations are conducted with an exposure time of 150 s and cadences of 10,20,and 30 d.The survey mode covering a total of 80 observations but with a random cadence in the range of 4 to 14 d is also explored.Our simulation results indicate that the CSST can detect up to ~1800 SNe la at z <1.3.The simulated SNe la are then used to constrain the cosmological parameters.The constraint on can be improved by 37.5% using the 10-d cadence sample in comparison with the Pantheon sample.A deeper measurement simulation with a 300 s exposure time together with the Pantheon sample improves the current constraints on Ωmby 58.3% and ω by 47.7%.Taking future lager sets of nearby SN Ⅰa sample form ground-based surveys(i.e.,N~3400) into consideration,the constraints on ω can be improved by 59.1%.The CSST ultra-deep field observation program is expected to discover large amounts of SNe la over a broad redshift span and enhance our understanding of the nature of dark energy.展开更多
DNA methylation is a prevalent epigenetic modification in vertebrates,and it has been shown to be involved the regulation of gene expression and embryo development.However,it remains unclear how DNA methylation regula...DNA methylation is a prevalent epigenetic modification in vertebrates,and it has been shown to be involved the regulation of gene expression and embryo development.However,it remains unclear how DNA methylation regulates sexual development,especially in species without sex chromosomes.To determine this,we utilized zebrafish to investigate DNA methylation reprogramming during juvenile germ cell development and adult female-to-male sex transition.We reveal that primordial germ cells(PGCs)undergo significant DNA methylation reprogramming during germ cell development,and the methylome of PGCs is reset to an oocyte/ovary-like pattern at 9 days post fertilization(9 dpf).When DNA methyltransferase(DNMT)activity in juveniles was blocked after 9 dpf,the zebrafish developed into females.We also show that Tet3 is involved in PGC development.Notably,we find that DNA methylome reprogramming during adult zebrafish sex transition is similar to the reprogramming during the sex differentiation from 9 dpf PGCs to sperm.Furthermore,inhibiting DNMT activity can prevent the female-to-male sex transition,suggesting that methylation reprogramming is required for zebrafish sex transition.In summary,DNA methylation plays important roles in zebrafish germ cell development and sexual plasticity.展开更多
Surface modification of magnesium alloy AZ91HP (9wt%Al, 0.5wt%Zn, 0.5wt%Mn, Mg remaining percentage) by high current pulsed electron beam (HCPEB) treatment was studied in this paper. The secondary phase MgnAln is near...Surface modification of magnesium alloy AZ91HP (9wt%Al, 0.5wt%Zn, 0.5wt%Mn, Mg remaining percentage) by high current pulsed electron beam (HCPEB) treatment was studied in this paper. The secondary phase MgnAln is nearly completely dissolved and as a result, a super-saturated solid solution forms on the re-melted surface. The microhardness is increased both in and far beyond the heat-affected zone (HAZ), reaching about 250um. Measurements on sliding wear have shown that the wear resistance of the treated samples was improved by a factor of about 2.4 as compared to the as-received sample. It is also found that the sliding wear resistance can be further improved by surface alloying with TiN.展开更多
The effects of amphiphilic O/W emulsions,stabilized by the alkyl polyglycoside(APG)or cholesterol-grafted sodium alginate(CSAD)/APG systems,on lambda-cyhalothrin adsorption/desorption mechanisms on natural soil minera...The effects of amphiphilic O/W emulsions,stabilized by the alkyl polyglycoside(APG)or cholesterol-grafted sodium alginate(CSAD)/APG systems,on lambda-cyhalothrin adsorption/desorption mechanisms on natural soil minerals(i.e.,illite and kaolinite)were investigated.Sorption and desorption of lambda-cyhalothrin onto soil minerals was studied via batch equilibration to give insight into the adsorption equilibrium,kinetics,and thermodynamics of lambda-cyhalothrin adsorption onto minerals.The results indicate the following:(i)The adsorption processes for the APG system and CSAD/APG system include:rapid adsorption,slow adsorption,and adsorption equilibrium.The adsorption kinetics of pesticide on illite and kaolinite are in accordance with the Ho and McKay model,and the adsorption isotherm conforms to the Freundlich model.In addition,the adsorption processes of pesticide for the two systems on minerals were spontaneous and feasible(ΔG^0<0),endothermic(ΔH^0>0),and mainly involved chemical bonding(ΔH^0>60).(ii)The equilibrium adsorption percentages of the pesticide on illite for the APG system and CSAD/APG system were 42.4%and 64.8%,and the corresponding equilibrium adsorption percentages on kaolinite were 40.8%and 61.8%,respectively.Moreover,the pesticide adsorption rate K_(2-CSAD/APG)was faster than K_(2-APG),and its adsorption capacity K_(f-CSAD/APG )was greater than K_(f-APG).Meanwhile,the pesticide desorption K_(fd)in the CSAD/APG system was smaller than that in the APG system.As a result,this eco-friendly O/W emulsion based on amphiphilic sodium alginate derivatives might provide a green pesticide formulation,since it could reduce the amount of lambda-cyhalothrin entering aquatic systems to threaten non-target fish and invertebrate species.展开更多
Large scale molecular dynamics simulations of nanomachining and stretching of single crystal copper are performed to analyze the machining process’ influence on the material’s mechanical properties. The simulation r...Large scale molecular dynamics simulations of nanomachining and stretching of single crystal copper are performed to analyze the machining process’ influence on the material’s mechanical properties. The simulation results show that the machining process will introduce interfacial defects inside the specimen and enhance the compressive stress beneath the surface. Gener- ally speaking, interfacial defects lead to the decrease of the strength limit, while residue compressive stress can enhance the elastic limit and even the strength limit. Various machining parameters are adopted to investigate their influence on the me- chanical behavior of machined specimen. Lower cutting speed and smaller cutting depth lead to less defects and greater residue compressive stress, which brings about better mechanical properties. The elastic limit increases by 36.8% under the cutting depth of 0.73 nm and decreases by 21.1% under the cutting depth of 1.46 nm. The strength limit increases by 7.7% under the cutting speed of 100 m/s and decreases by 28.2% under the cutting speed of 300 m/s.展开更多
Coal bed methane （CBM） has a huge potential to be purified to relieve the shortage of natural gas meanwhile to weaken the greenhouse effect. This paper proposed an optimal design strategy for CBM to obtain an integr...Coal bed methane （CBM） has a huge potential to be purified to relieve the shortage of natural gas meanwhile to weaken the greenhouse effect. This paper proposed an optimal design strategy for CBM to obtain an integrated process configuration consisting of three each single separation units, membrane, pressure swing absorption, and cryogenics. A superstructure model was established including all possible network configurations which were solved by MINLP. The design strategy optimized the separation unit configuration and operating conditions to satisfy the target of minimum total annual process cost. An example was presented for the separation of CH4/N2 mixtures in coal bed methane （CBM） treatment. The key operation parameters were also studied and they showed the influence to process configurations.展开更多
The height of fractured zone(HFZ) at the high-intensity longwall mining panel plays a vital role in the safety analysis of coal mining under bodies of water. This paper described definitions of the highintensity minin...The height of fractured zone(HFZ) at the high-intensity longwall mining panel plays a vital role in the safety analysis of coal mining under bodies of water. This paper described definitions of the highintensity mining. The processes of overburden failure transfer(OFT) were analyzed, which were divided into the development stage and the termination stage. Through theoretical analysis, the limited suspension-distance and the limited overhanging distance were proposed to judge the damage of each stratum. Mechanical models of strata suspended integrity and overhanging stability were established.A theoretical method to predict the HFZ at the high-intensity longwall mining panel was put forward based on the processes of OFT. Taking a high-intensity longwall mining panel(No. 11915 panel) as an example, the theoretical method proposed, the engineering analogy and the empirical formulas in the Regulation were used to predict the HFZ. The results show that the theoretical result is consistent with the engineering analogies' result and empirical formulas' result. The rationality and reliability of the theoretical method proposed is verified.展开更多
High-power electric actuators are generally used on solid propellant motors,which further enhances the requirement on onboard supply voltage and output power of a launch vehicle.In this paper,combined with the electri...High-power electric actuators are generally used on solid propellant motors,which further enhances the requirement on onboard supply voltage and output power of a launch vehicle.In this paper,combined with the electrical demand of China’s new generation solid-liquid bundled launch vehicle(LM-6 A),high-voltage battery technology,high-power switch control technology,insulation protection technology under low pressure are studied,and the key technologies and schemes are presented.The flight test of LM-6 A shows that the high-voltage power supply and distribution technology adopted is reasonable and feasible,and can be used as a reference for the designs of other launch vehicles or spacecrafts.展开更多
The Type-B authentic response regulator(ARR-Bs)gene family is one of the important plant-specific transcription factor families involved in variety of physiological processes.However,study of ARR-Bs gene family in soy...The Type-B authentic response regulator(ARR-Bs)gene family is one of the important plant-specific transcription factor families involved in variety of physiological processes.However,study of ARR-Bs gene family in soybean is limited.Genome-wide analysis and expression profiling of the ARR-Bs gene family were performed in the soybean genome.31 ARR-Bs genes(namely GmARR-B1-31)were identified,containing conserved catalytic domains with protein lengths and molecular weights ranging from 246 to 699 amino acids(aa)and 28.30 to 76.86 kDa,respectively.Phylogenetic analysis grouped ARR-Bs genes into three clusters—Cluster I,Cluster II,and Cluster III—which included 15,12,and 4 genes,respectively,and were asymmetrically distributed on 17 chromosomes.Tissue specific expression analysis of GmARR-Bs family revealed a high transcription level in flowers,roots and seeds.The subcellular localization of GmARR5,GmARR14 were observed in the nucleus,and the promoter region of them included low-temperature responsive element(LTR),the C-repeat/dehydration responsive element(DRE),MBS,ABRE,MYB,MEJA and TCA-elements,which possibly participate in abiotic stress and hormones responses.qRTPCR analysis showed that the expression of GmARR-B genes were affected by different abiotic stresses,especially cold stress and salt stress,and GmARR-B5 and GmARR-B14 were significantly induced by cold stress.This suggested that ARR-Bs genes were involved in multiple abiotic stress response pathways and acted as a positive factor under cold stress.展开更多
Surface treatment of magnesium alloys AZ31 and AZ91HP by a high current pulsed electron beam (HCPEB) was investigated in the present paper. The corrosion resistance of treated samples was tested in a 5% (wt%) NaCl sol...Surface treatment of magnesium alloys AZ31 and AZ91HP by a high current pulsed electron beam (HCPEB) was investigated in the present paper. The corrosion resistance of treated samples was tested in a 5% (wt%) NaCl solution, showing remarkably improvement as manifested by polarization curves. According to EPMA analysis, the intermetallic Mg17Al12 in the surface layer of AZ91HP sample almost disappeared after the treatment of HCPEB, leaving the surface layer in a state of supersaturated solid solution. Both the augmentation of aluminum content and the formation of supersaturated structure in the surface layer are believed to contribute to the improved corrosion resistance of AZ31 and AZ91HP.展开更多
In this study,surface modification of monocrystalline silicon with two doses of hydrogen ion implantation and the plunge cutting process were conducted to explore the influence of hydrogen ions on the cutting behavior...In this study,surface modification of monocrystalline silicon with two doses of hydrogen ion implantation and the plunge cutting process were conducted to explore the influence of hydrogen ions on the cutting behavior of silicon.The results show that ion implantation is capable of deteriorating or improving the machinability of silicon,depending on the implantation dose.More cleavages and a reduction of critical depth of cut(CDoC)were observed for the silicon with a low implantation dose in the cutting direction of<100>in comparison to bare silicon,while no cleavage and an increase of CDoC were achieved after implantation with a high dose in the same cutting direction.Besides,the ductile cutting and thrust forces of the silicon with the low dose are larger than the bare silicon,but the forces are significantly reduced for the silicon after the high dose of implantation.The variation of the cutting forces is due to the different required stresses to overcome ductile and fracture deformation of silicon.展开更多
Soil aggregation plays an important role in agricultural production activities.However,the structure of soil aggregation is destroyed by the natural environment and unreasonable farming management,resulting in the los...Soil aggregation plays an important role in agricultural production activities.However,the structure of soil aggregation is destroyed by the natural environment and unreasonable farming management,resulting in the loss of water,fertilizers and pesticides in soil.At present,hydrogels have been widely reported to promote the formation of soil aggregation.In this paper,amphiphilic calcium alginate(ASA/Ca^(2+))was applied to promote the formation of soil aggregation and enhance pesticide retention.Initially,an ASA was obtained through the one-pot Ugi condensation(a four-component green chemical reaction).Then,ASA/Ca^(2+) hydrogel is prepared by Ca^(2+) cross-linking.The formation of soil aggregation was determined through the Turbiscan Lab Expert stability analyzer,Confocal Laser Scanning Microscope(CLSM),and Transmission Electron Microscope(TEM).And the effect of soil aggregation on acetamiprid environmental behavior was investigated by adsorption kinetics,adsorption isotherms,and leaching.The results shown that the three-dimensional network structure of ASA/Ca^(2+) hydrogel can promote the formation of soil aggregation.Aggregate durability index(ADI)was 0.55 in the presence of ASA/Ca^(2+) hydrogel,indicating that amphiphilic hydrogel can enhance the stability of soil aggregation.The adsorbing capacity of acetamiprid was 1.58 times higher than pure soil,and the release of acetamiprid only about 20%in the presence of ASA/Ca^(2+) hydrogel.These results would be helpful for the formation of soil aggregation and pesticides adsorption on soil aggregation.Thus,ASA/Ca^(2+) hydrogel is likely to improve soil quality,simultaneously it can minimize the mobility of pesticides in the agricultural system.展开更多
基金Supported by the National Natural Science Foundation (No.30973795)
文摘OBJECTIVE:To study the effects of temperature on different facial areas by suspended moxibustion at two points,Zusanli(ST 36) and Hegu(LI 4),and probe the phenomena underlying self-regulation in the human body after thermal stimulation.METHODS:Thirty healthy volunteers accepted moxibustion over Zusanli(ST 36) and Hegu(LI 4),and the order of moxibustion points was randomly determined.Moxibustion method:suspension of moxibustion over Zusanli(ST 36) and Hegu(LI 4) on both sides was performed using an ignited moxa stick stuck in a support for 20 min.Observation method:An infrared thermal image of the face was taken before and after suspended moxibustion using a CK350 medical infrared thermal imaging instrument.Data analysis:A thermal microscopic section view system(TMTSys) was used to analyze the change in temperature in special facial areas.Statistical analysis was carried out using SPSS 14.0 software.RESULTS:Before moxibustion was suspended,the facial thermal image showed a T-shaped thermal area related to the vascular distribution with even temperature and good symmetry on both sides.Suspended moxibustion over Zusanli(ST 36) have a very significant increase in temperature at the forehead,around the nose,at the corners of the mouth,and at the cheeks and lips(P<0.01).Suspended moxibustion over Hegu(LI 4) also have a significant(P<0.05) increase in temperature around the nose,the corners of the mouth,the cheeks,and lips,where has a new high temperature area was formed(P<0.01).Suspended moxibustion over Hegu(LI 4) raised the temperature at the middle point of the lips more obviously than did Zusanli(ST 36) in the same person,(P<0.05).After 10 min of moxibustion over Zusanli(ST 36) and Hegu(LI 4),the change in temperature in the facial area reached its peak value.CONCLUSIONS:Facial infrared thermography of healthy people revealed a T-shaped thermal area reflecting a physiological thermal area.Moxibustion over Zusanli(ST 36) or Hegu(LI 4) raised the temperature in this facial T-shaped thermal area.Hegu(LI 4) led to the
基金supported by the National Natural Science Foundation of China,No.30973795
文摘Subjects with Bell＇s palsy and healthy individuals were treated with moxibustion thermal stimulation on the Hegu （LI4） acupoint; an infrared thermal imaging system was used to observe facial-temperature changes. Bell＇s palsy patients developed low or high temperatures at the affected side, with poor symmetry. Healthy people showed high temperatures on the forehead, medial angle of the eye, nasal ala and around the lips, but low temperatures on bilateral cheeks, thus forming a ＂T-type hot area＂ in the face, with good temperature symmetry. Moxibustion treatment for 11 minutes significantly improved high asymmetry in temperature in the faces of Bell＇s palsy patients. This evidence indicates that moxibustion treatment on Hegu enables increases in facial temperatures in healthy people and Bell＇s palsy patients, especially around the lips. Moxibustion stimulation at the Hegu not only improves the global circulation but also has specific effects on the lips in Bell＇s palsy patients, but the underlying mechanism needs further investigation.
基金This work was supported by grants from the Key R&D Project of Shaanxi Province(No.2020GXLH-Z-001)the National Key R&D Project of China(No.2018YFC0115300 and No.2018YFC0115305)+1 种基金the National Natural Science Foundation of China(No.81727802,12172272,11702208,11820101001)China Postdoctoral Science Foundation(No.BX201700192,2018M643620).
文摘The recent development of tough tissue adhesives has stimulated intense interests among material scientists and medical doctors.However,these adhesives have seldom been tested in clinically demanding surgeries.Here we demonstrate adhesive anastomosis in organ transplantation.Anastomosis is commonly conducted by dense sutures and takes a long time,during which all the vessels are occluded.Prolonged occlusion may damage organs and even cause death.We formulate a tough,biocompatible,bioabsorbable adhesive that can sustain tissue tension and pressurized flow.We expose the endothelial surface of vessels onto a gasket,press two endothelial surfaces to the adhesive using a pair of magnetic rings,and reopen the bloodstream immediately.The time for adhesive anastomosis is shortened compared to the time for sutured anastomosis.We have achieved adhesive anastomosis of a great vein in transplanting the liver of a pig.After the surgery,the adhesive is absorbed,the vein heals,and the pig lives for over one month.
基金supported by the China Manned Spaced Project (Grant Nos. CMS-CSST-2021-A12, CMS-CSST-2021-B01, and CMS-CSST-2021B04)National Natural Science Foundation of China (Grant Nos. 12288102, and 12033003)+5 种基金Scholar Program of Beijing Academy of Science and Technology (Grant No. DZ:BS202002)Tencent Xplorer Prizesupported by the Beijing Postdoctoral Research Foundationsupported by the Informatization Plan of Chinese Academy of Sciences (Grant No. CAS-WX2021PY-0101)supported by the State Key Program of National Natural Science Foundation of China (Grant No. 12233008)supported by the project “Transient Astrophysical Objects” GINOP 2.3.2-15-2016-00033 of the National Research, Development and Innovation Office (NKFIH), Hungary, funded by the European Union。
文摘The 2-m aperture Chinese Space Station Telescope(CSST),which observes at wavelengths ranging from 255 to 1000 nm,is expected to start science operations in 2024.An ultra-deep field observation program covering approximately 10 deg2is proposed with supernovae(SNe) and other transients as one of its primary science drivers.This paper presents the simulated detection results of type Ⅰa supernovae(SNe Ⅰa) and explores the impact of new datasets on the determinations of cosmological parameters.The simulated observations are conducted with an exposure time of 150 s and cadences of 10,20,and 30 d.The survey mode covering a total of 80 observations but with a random cadence in the range of 4 to 14 d is also explored.Our simulation results indicate that the CSST can detect up to ~1800 SNe la at z <1.3.The simulated SNe la are then used to constrain the cosmological parameters.The constraint on can be improved by 37.5% using the 10-d cadence sample in comparison with the Pantheon sample.A deeper measurement simulation with a 300 s exposure time together with the Pantheon sample improves the current constraints on Ωmby 58.3% and ω by 47.7%.Taking future lager sets of nearby SN Ⅰa sample form ground-based surveys(i.e.,N~3400) into consideration,the constraints on ω can be improved by 59.1%.The CSST ultra-deep field observation program is expected to discover large amounts of SNe la over a broad redshift span and enhance our understanding of the nature of dark energy.
基金supported by the grants from the Ministry of Science and Technology of China(Grant No.2018YFC1003300)the National Natural Science Foundation of China(Grant Nos.31630040,81871171,31871454 and 31671540)+2 种基金the CAS Funding(Grant No.QYZDY-SSWSMC016)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB38020500)the Youth Innovation Promotion Association of the Chinese Academy of Sciences(Grant No.292020000011)
文摘DNA methylation is a prevalent epigenetic modification in vertebrates,and it has been shown to be involved the regulation of gene expression and embryo development.However,it remains unclear how DNA methylation regulates sexual development,especially in species without sex chromosomes.To determine this,we utilized zebrafish to investigate DNA methylation reprogramming during juvenile germ cell development and adult female-to-male sex transition.We reveal that primordial germ cells(PGCs)undergo significant DNA methylation reprogramming during germ cell development,and the methylome of PGCs is reset to an oocyte/ovary-like pattern at 9 days post fertilization(9 dpf).When DNA methyltransferase(DNMT)activity in juveniles was blocked after 9 dpf,the zebrafish developed into females.We also show that Tet3 is involved in PGC development.Notably,we find that DNA methylome reprogramming during adult zebrafish sex transition is similar to the reprogramming during the sex differentiation from 9 dpf PGCs to sperm.Furthermore,inhibiting DNMT activity can prevent the female-to-male sex transition,suggesting that methylation reprogramming is required for zebrafish sex transition.In summary,DNA methylation plays important roles in zebrafish germ cell development and sexual plasticity.
文摘Surface modification of magnesium alloy AZ91HP (9wt%Al, 0.5wt%Zn, 0.5wt%Mn, Mg remaining percentage) by high current pulsed electron beam (HCPEB) treatment was studied in this paper. The secondary phase MgnAln is nearly completely dissolved and as a result, a super-saturated solid solution forms on the re-melted surface. The microhardness is increased both in and far beyond the heat-affected zone (HAZ), reaching about 250um. Measurements on sliding wear have shown that the wear resistance of the treated samples was improved by a factor of about 2.4 as compared to the as-received sample. It is also found that the sliding wear resistance can be further improved by surface alloying with TiN.
基金supported by the Key Projects in the Hainan provincial Science & Technology Program (Nos. ZDYF2018061, ZDYF2018107)the National Natural Science Foundation of China (Nos. 21566009, 21706045)+1 种基金the Natural Science Foundation of Hainan Province (No. 217021)the Key Laboratory of Water Environment Pollution Treatment & Resource of Hainan Province
文摘The effects of amphiphilic O/W emulsions,stabilized by the alkyl polyglycoside(APG)or cholesterol-grafted sodium alginate(CSAD)/APG systems,on lambda-cyhalothrin adsorption/desorption mechanisms on natural soil minerals(i.e.,illite and kaolinite)were investigated.Sorption and desorption of lambda-cyhalothrin onto soil minerals was studied via batch equilibration to give insight into the adsorption equilibrium,kinetics,and thermodynamics of lambda-cyhalothrin adsorption onto minerals.The results indicate the following:(i)The adsorption processes for the APG system and CSAD/APG system include:rapid adsorption,slow adsorption,and adsorption equilibrium.The adsorption kinetics of pesticide on illite and kaolinite are in accordance with the Ho and McKay model,and the adsorption isotherm conforms to the Freundlich model.In addition,the adsorption processes of pesticide for the two systems on minerals were spontaneous and feasible(ΔG^0<0),endothermic(ΔH^0>0),and mainly involved chemical bonding(ΔH^0>60).(ii)The equilibrium adsorption percentages of the pesticide on illite for the APG system and CSAD/APG system were 42.4%and 64.8%,and the corresponding equilibrium adsorption percentages on kaolinite were 40.8%and 61.8%,respectively.Moreover,the pesticide adsorption rate K_(2-CSAD/APG)was faster than K_(2-APG),and its adsorption capacity K_(f-CSAD/APG )was greater than K_(f-APG).Meanwhile,the pesticide desorption K_(fd)in the CSAD/APG system was smaller than that in the APG system.As a result,this eco-friendly O/W emulsion based on amphiphilic sodium alginate derivatives might provide a green pesticide formulation,since it could reduce the amount of lambda-cyhalothrin entering aquatic systems to threaten non-target fish and invertebrate species.
基金supported by the National Natural Science Foundation of China (Grant No. 50935003)the National High Technology Research and Development Program of China (Grant No. 2009AA044305)
文摘Large scale molecular dynamics simulations of nanomachining and stretching of single crystal copper are performed to analyze the machining process’ influence on the material’s mechanical properties. The simulation results show that the machining process will introduce interfacial defects inside the specimen and enhance the compressive stress beneath the surface. Gener- ally speaking, interfacial defects lead to the decrease of the strength limit, while residue compressive stress can enhance the elastic limit and even the strength limit. Various machining parameters are adopted to investigate their influence on the me- chanical behavior of machined specimen. Lower cutting speed and smaller cutting depth lead to less defects and greater residue compressive stress, which brings about better mechanical properties. The elastic limit increases by 36.8% under the cutting depth of 0.73 nm and decreases by 21.1% under the cutting depth of 1.46 nm. The strength limit increases by 7.7% under the cutting speed of 100 m/s and decreases by 28.2% under the cutting speed of 300 m/s.
基金supported by the National Natural Science Foundation of China(Grant No.51176051)the PetroChina Innovation Foundation(2012D- 5006-0210)the Colleges and Universities High-level Talents Program of Guangdong
文摘Coal bed methane （CBM） has a huge potential to be purified to relieve the shortage of natural gas meanwhile to weaken the greenhouse effect. This paper proposed an optimal design strategy for CBM to obtain an integrated process configuration consisting of three each single separation units, membrane, pressure swing absorption, and cryogenics. A superstructure model was established including all possible network configurations which were solved by MINLP. The design strategy optimized the separation unit configuration and operating conditions to satisfy the target of minimum total annual process cost. An example was presented for the separation of CH4/N2 mixtures in coal bed methane （CBM） treatment. The key operation parameters were also studied and they showed the influence to process configurations.
基金supported by the National Natural Science Foundation of China (No.51774111)Henan province science and technology innovation outstanding talent fund of China (No.184200510003)
文摘The height of fractured zone(HFZ) at the high-intensity longwall mining panel plays a vital role in the safety analysis of coal mining under bodies of water. This paper described definitions of the highintensity mining. The processes of overburden failure transfer(OFT) were analyzed, which were divided into the development stage and the termination stage. Through theoretical analysis, the limited suspension-distance and the limited overhanging distance were proposed to judge the damage of each stratum. Mechanical models of strata suspended integrity and overhanging stability were established.A theoretical method to predict the HFZ at the high-intensity longwall mining panel was put forward based on the processes of OFT. Taking a high-intensity longwall mining panel(No. 11915 panel) as an example, the theoretical method proposed, the engineering analogy and the empirical formulas in the Regulation were used to predict the HFZ. The results show that the theoretical result is consistent with the engineering analogies' result and empirical formulas' result. The rationality and reliability of the theoretical method proposed is verified.
文摘High-power electric actuators are generally used on solid propellant motors,which further enhances the requirement on onboard supply voltage and output power of a launch vehicle.In this paper,combined with the electrical demand of China’s new generation solid-liquid bundled launch vehicle(LM-6 A),high-voltage battery technology,high-power switch control technology,insulation protection technology under low pressure are studied,and the key technologies and schemes are presented.The flight test of LM-6 A shows that the high-voltage power supply and distribution technology adopted is reasonable and feasible,and can be used as a reference for the designs of other launch vehicles or spacecrafts.
基金This work was financially supported by the National Modern Agricultural Industrial Technology System(CARS-04-01A).
文摘The Type-B authentic response regulator(ARR-Bs)gene family is one of the important plant-specific transcription factor families involved in variety of physiological processes.However,study of ARR-Bs gene family in soybean is limited.Genome-wide analysis and expression profiling of the ARR-Bs gene family were performed in the soybean genome.31 ARR-Bs genes(namely GmARR-B1-31)were identified,containing conserved catalytic domains with protein lengths and molecular weights ranging from 246 to 699 amino acids(aa)and 28.30 to 76.86 kDa,respectively.Phylogenetic analysis grouped ARR-Bs genes into three clusters—Cluster I,Cluster II,and Cluster III—which included 15,12,and 4 genes,respectively,and were asymmetrically distributed on 17 chromosomes.Tissue specific expression analysis of GmARR-Bs family revealed a high transcription level in flowers,roots and seeds.The subcellular localization of GmARR5,GmARR14 were observed in the nucleus,and the promoter region of them included low-temperature responsive element(LTR),the C-repeat/dehydration responsive element(DRE),MBS,ABRE,MYB,MEJA and TCA-elements,which possibly participate in abiotic stress and hormones responses.qRTPCR analysis showed that the expression of GmARR-B genes were affected by different abiotic stresses,especially cold stress and salt stress,and GmARR-B5 and GmARR-B14 were significantly induced by cold stress.This suggested that ARR-Bs genes were involved in multiple abiotic stress response pathways and acted as a positive factor under cold stress.
基金the scientific research foundation for the returned overseas Chinese scholars from state education ministry of P.R.China.
文摘Surface treatment of magnesium alloys AZ31 and AZ91HP by a high current pulsed electron beam (HCPEB) was investigated in the present paper. The corrosion resistance of treated samples was tested in a 5% (wt%) NaCl solution, showing remarkably improvement as manifested by polarization curves. According to EPMA analysis, the intermetallic Mg17Al12 in the surface layer of AZ91HP sample almost disappeared after the treatment of HCPEB, leaving the surface layer in a state of supersaturated solid solution. Both the augmentation of aluminum content and the formation of supersaturated structure in the surface layer are believed to contribute to the improved corrosion resistance of AZ31 and AZ91HP.
基金The work described in this paper was jointly supported by the Research Committee(Project No.G-YBLE)State Key Laboratory of Ultra-precision Machining Technology(Project No.RUWB)of the Hong Kong Polytechnic University.
文摘In this study,surface modification of monocrystalline silicon with two doses of hydrogen ion implantation and the plunge cutting process were conducted to explore the influence of hydrogen ions on the cutting behavior of silicon.The results show that ion implantation is capable of deteriorating or improving the machinability of silicon,depending on the implantation dose.More cleavages and a reduction of critical depth of cut(CDoC)were observed for the silicon with a low implantation dose in the cutting direction of<100>in comparison to bare silicon,while no cleavage and an increase of CDoC were achieved after implantation with a high dose in the same cutting direction.Besides,the ductile cutting and thrust forces of the silicon with the low dose are larger than the bare silicon,but the forces are significantly reduced for the silicon after the high dose of implantation.The variation of the cutting forces is due to the different required stresses to overcome ductile and fracture deformation of silicon.
基金suppoted by the Key Projects in the Hainan provincial Science&Technology Program(No.ZDYF2020191)the National Natural Science Foundation of China(Nos.22068011,22007025)+1 种基金the Natural Science Foundation of Hainan Province(Nos.220MS006,220QN182)the Start-up Grants from Hainan University(Nos.KYQD(ZR)20041,KYQD(ZR)20040).
文摘Soil aggregation plays an important role in agricultural production activities.However,the structure of soil aggregation is destroyed by the natural environment and unreasonable farming management,resulting in the loss of water,fertilizers and pesticides in soil.At present,hydrogels have been widely reported to promote the formation of soil aggregation.In this paper,amphiphilic calcium alginate(ASA/Ca^(2+))was applied to promote the formation of soil aggregation and enhance pesticide retention.Initially,an ASA was obtained through the one-pot Ugi condensation(a four-component green chemical reaction).Then,ASA/Ca^(2+) hydrogel is prepared by Ca^(2+) cross-linking.The formation of soil aggregation was determined through the Turbiscan Lab Expert stability analyzer,Confocal Laser Scanning Microscope(CLSM),and Transmission Electron Microscope(TEM).And the effect of soil aggregation on acetamiprid environmental behavior was investigated by adsorption kinetics,adsorption isotherms,and leaching.The results shown that the three-dimensional network structure of ASA/Ca^(2+) hydrogel can promote the formation of soil aggregation.Aggregate durability index(ADI)was 0.55 in the presence of ASA/Ca^(2+) hydrogel,indicating that amphiphilic hydrogel can enhance the stability of soil aggregation.The adsorbing capacity of acetamiprid was 1.58 times higher than pure soil,and the release of acetamiprid only about 20%in the presence of ASA/Ca^(2+) hydrogel.These results would be helpful for the formation of soil aggregation and pesticides adsorption on soil aggregation.Thus,ASA/Ca^(2+) hydrogel is likely to improve soil quality,simultaneously it can minimize the mobility of pesticides in the agricultural system.
