China's bee industry is a small proportion of domestic agriculture with fewer farmers, and the government didn't attach much attention to or give supports to it. Agricultural production sector does not fully r...China's bee industry is a small proportion of domestic agriculture with fewer farmers, and the government didn't attach much attention to or give supports to it. Agricultural production sector does not fully recognize the economic value of honeybee pollination. Chinese beekeepers gain profits only from products such as honey, royal jelly and bee pollen. Because of the production mode that aims at gathering and producing more honey while neglecting the health care of bees and the quality of products; export enterprises lack guidance and knowledge in export inspection and quarantine and technical regulations, and thus, the average price of China's bee honey exports is much lower than that of other countries in the world. Meanwhile, in domestic market, given the sustained development of China's macro economy and increasing incomes of residents, people show increasing interests in the health care function of honey. Based on the survey data of honey market in Beijing, Hangzhou, Qingdao, Zhengzhou and Chengdu from 2012 to 2015, the paper analyzes the price feature of China's honey market and its formulation basis, and also compares prices of honey with the same quality in different markets. Moreover, the paper combines data from fixed observation places of honey products production, which is carried out by the economic research group of bee industry in 11 provinces, to discuss reasons for continuous honey price rising in domestic market. Lastly, the paper uses the honey as an example to analyze pricing strategy of agricultural products with health care functions. The paper hold the opinions that the keys to solve the problem that high quality agricultural material couldn't sell in high price and good and bad are mixed in the market, is to build up quality and price mechanism in the processing of raw material purchasing to the terminal market, publicize more products information and superior customer attractiveness on health care effect.展开更多
In this study,perovskite-type La_(0.7)Ca_(0.3)Co_(0.3)Fe_(0.6)M_(0.1)O_(3-δ)(M=Cu,Zn)powders were synthesized using a scalable reverse co-precipitation method,presenting them as novel materials for oxygen transport m...In this study,perovskite-type La_(0.7)Ca_(0.3)Co_(0.3)Fe_(0.6)M_(0.1)O_(3-δ)(M=Cu,Zn)powders were synthesized using a scalable reverse co-precipitation method,presenting them as novel materials for oxygen transport membranes.The comprehensive study covered various aspects including oxygen permeability,crystal structure,conductivity,morphology,CO_(2) tolerance,and long-term regenerative durability with a focus on phase structure and composition.The membrane La_(0.7)Ca_(0.3)Co_(0.3)Fe_(0.6)M_(0.1)O_(3-δ)exhibited high oxygen permeation fluxes,reaching up to 0.88 and 0.64 mL·min^(−1)·cm^(−2) under air/He and air/CO_(2) gradients at 1173 K,respectively.After 1600 h of CO_(2) exposure,the perovskite structure remained intact,showcasing superior CO_(2) resistance.A combination of first principles simulations and experimental measurements was employed to deepen the understanding of Cu/Zn substitution effects on the structure,oxygen vacancy formation,and transport behavior of the membranes.These findings underscore the potential of this highly CO_(2)-tolerant membrane for applications in high-temperature oxygen separation.The enhanced insights into the oxygen transport mechanism contribute to the advancement of next-generation membrane materials.展开更多
The Hengduan Mountains is in the transitional zone between the Qinghai-Tibet Plateau(QTP)and the YunnanGuizhou Plateau in China,and a key area for elucidating the Quaternary environmental changes in Asia.The paleo-Dao...The Hengduan Mountains is in the transitional zone between the Qinghai-Tibet Plateau(QTP)and the YunnanGuizhou Plateau in China,and a key area for elucidating the Quaternary environmental changes in Asia.The paleo-Daocheng ice cap was located on the Shaluli Hilly Plateau in the northeastern Hengduan Mountains,the oldest moraines in the Hengduan Mountains region were found in the ice cap area.Such glacial landforms provide key evidence to study the timing when this area entered the cryosphere with the uplift of the QTP.However,it is difficult to collect suitable glacial boulders from these moraines for traditional terrestrial in-situ cosmogenic nuclide(TCN)exposure dating because of long-term severe moraine degradation.Here,we collected clast samples from the moraine surface and depth profile to constrain the age of the oldest moraine in Kuzhaori(moraine E)using TCN^(10)Be dating technique.The minimum^(10)Be ages of five clast samples from the moraine surface range from 187.4±1.5 to 576.8±4.3 ka,implying that the moraine has been seriously degraded since deposition.Based on the TCN^(10)Be concentrations of the samples from a depth profile and simulations,the exposure-erosion-inheritance history of the profile was obtained.By fitting to the profile^(10)Be concentrations using the chi-square test,the simulations yielded a reliable age of 626.0±52.5 ka for the moraine.Therefore,the oldest moraine(moraine E)in Kuzhaori was most likely formed at about 0.63Ma ago,corresponding to the marine isotope stage(MIS)16.This glaciation represents the maximum Quaternary glaciation after the QTP was elevated into the cryosphere by the Kunlun-Yellow River Tectonic Movement.展开更多
The thermoneutral zone(TNZ)reflects the adaptation of mammals to their natural habitat.However,it remains unclear how TNZ shifts in response to variations in ambient temperature.To test the hypothesis that ambient temp...The thermoneutral zone(TNZ)reflects the adaptation of mammals to their natural habitat.However,it remains unclear how TNZ shifts in response to variations in ambient temperature.To test the hypothesis that ambient temperature plays a key role in determining TNZ variations between seasons,we measured metabolic rate,body temperature,and cytochrome c oxidase(COX)activity of several visceral organs in striped hamsters(Cricetulus barabensis)either acclimated to semi-natural conditions over a year,or subjected to a gradual decrease in mean temperature from 30±1°C to-15±1°C.The TNZ range in striped hamsters differed seasonally,with a wider TNZ and a lower lower-critical temperature in winter compared to summer.The hamsters showed a consider-able leftward shift of lower-critical temperature from 30°C to 20°C after the ambient temperature of acclimation from 30°C down to-15°C,whereas the upper-critical temperature of TNZ remainedfixed at 32.5°C.The rest-ing metabolic rate in thermoneutral zone(RMRt),nonshivering thermogenesis(NST),and COX activity of brown adipose tissue,liver,skeletal muscle,brain,and kidneys,increased significantly in hamsters acclimated at lower ambient temperatures.Following acute exposure to 5°C and-15°C,hamsters acclimated to 32.5°C had signifi-cantly lower maximal NST and lower serum thyroid tri-iodothyronine(T3)levels compared to those kept at 23°C.Thesefindings suggest that acclimation to the upper-critical temperature of TNZ impairs the hamsters’thermo-genic capacity to cope with extreme cold temperature.Reduced ambient temperature was mainly responsible for the leftward shift of TNZ in striped hamsters,which reflects the adaptation to cold environments.展开更多
Large-sized cranial bone defect repair presents a great challenge in the clinic.The ideal cranioplasty materials to realize the functional and cosmetic recovery of the defect must have sufficient mechanical support,ex...Large-sized cranial bone defect repair presents a great challenge in the clinic.The ideal cranioplasty materials to realize the functional and cosmetic recovery of the defect must have sufficient mechanical support,excellent biocompatibility,good osseointegration and biodegradability as well.In this study,a high-strength mineralized collagen(MC)bone scaffold was developed with biomimetic composition,microstructure and mechanical properties for the repair of sheep largesized cranial bone defects in comparison with two traditional cranioplasty materials,polymethyl methacrylate and titanium mesh.The compact MC scaffold showed no distinct pore structure and therefore possessed good mechanical properties.The strength and elastic modulus of the scaffold were much higher than those of natural cancellous bone and slightly lower than those of natural compact bone.In vitro cytocompatibility evaluation revealed that the human bone marrow mesenchymal stem cells(hBMSC)had good viability,attachment and proliferation on the compact MC scaffold indicating its excellent biocompatibility.An adult sheep cranial bone defect model was constructed to evaluate the performances of these cranioplasty materials in repairing the cranial bone defects.The results were investigated by gross observation,computed tomography scanning as well as histological assessments.The in vivo evaluations indicated that compact MC scaffold showed notable osteoconductivity and osseointegration with surrounding cranial bone tissues by promoting bone regeneration.Our results suggested that the compact MC scaffold has a promising potential for large-sized cranial bone defect repair.展开更多
South China preserves a rich archaeological record elucidating the evolution of early modern humans during the Late Pleistocene.However,few studies on plant utilization were conducted in this region.We used phytolith ...South China preserves a rich archaeological record elucidating the evolution of early modern humans during the Late Pleistocene.However,few studies on plant utilization were conducted in this region.We used phytolith analysis from Yahuai Cave,Guangxi,to infer human use of plant resources over the past 30000 years.AMS 14C dating was used to constrain the chronological framework.Results indicate that several economically essential species were present throughout the sequence including Urticineae(cf.Ulmus sp.),which appears in the lower layers of the sequence(Marine Isotope Stage 3 through Heinrich 1);bamboo and palm which appear throughout the sequence,and wild rice which appears in a clear archaeological context dating to 16000 years ago.This is the earliest record of wild rice in South China and a prerequisite for rice domestication.The unique stone tool assemblages,which resemble those in north China as opposed to South China,point to the possibility that humans,seeking refuge from the colder north,brought their tool kit with them and utilized familiar northern taxa.Warmer South China would have served as a refuge for human populations escaping the cold,harsh climate in the north with more ameliorate conditions in the south.展开更多
The life history of many animals includes periods of food shortage.Two behavioral strategies are involved in small mammals in response to food shortage:an increase in activity behavior,representing the increased forag...The life history of many animals includes periods of food shortage.Two behavioral strategies are involved in small mammals in response to food shortage:an increase in activity behavior,representing the increased foraging or migratory behavior,and a decrease in activity level,serving as a mechanism for conserving energy.However,it is uncertain whether animals adopt both strategies in response to food shortage,and whether hormone and neuroendocrine mechanisms are involved in both strategies.In the present study,changes in behavior and metabolic rate were examined in food-deprived striped hamsters(Cricetulus barabensis).The effects of leptin supplement on activity behavior,metabolic rate and hypothalamic neuropeptide gene expression were also examined.The behavior of food-deprived hamsters significantly changed with photoperiod phases:with increasing activity during the dark phase compared to those fed ad libitum,whereas decreasing activity and simultaneously increasing resting behavior during the light phase.Resting metabolic rate,body mass,and masses of fat depots and digestive tracts significantly decreased in food-deprived hamsters compared with ad libitum controls.Leptin supplement tended to attenuate the increased activity in the dark phase.Gene expression of hypothalamic neuropeptide Y(NPY)was significantly upregulated in food-deprived hamsters,while was significantly attenuated by exogenous leptin.These findings suggest that both behavior strategies are important behavioral adjustments in free-living animals to cope with food shortage.Leptin and hypothalamic NPY gene expression may be involved in the adjustments of physiology and behavior in animals demonstrating a hyperactivity strategy in response to food shortage.展开更多
Desert hamsters(Phodopus roborovskii)are the least known species in the genus Phodopus with respect to ecology and physiology,and deserve scientific attention,particularly because of their small body size.Here,the res...Desert hamsters(Phodopus roborovskii)are the least known species in the genus Phodopus with respect to ecology and physiology,and deserve scientific attention,particularly because of their small body size.Here,the responses of energy metabolism and reproductive function to short photoperiods in desert hamsters were investigated.Male and female desert hamsters were acclimated to either long day(LD)(L:D 16:8 h)or short day(SD)photoperiods(L:D 8:16 h)for three months,and then the females were transferred back to an LD photoperiod for a further five months,while at the end of the SD acclimation the males were killed and measurements were taken for serum leptin as well as molecular markers for thermogenesis.We found that like the other two species from the genus Phodopus,the desert hamsters under SD decreased body mass,increased adaptive thermogenesis as indicated by elevated mitochondrial protein content and uncoupling protein-1 content in brown adipose tissue,and suppressed reproduction compared to those under LD.However,different from the other two species,desert hamsters did not show any differences in energy intake or serum leptin concentration between LD and SD.These data suggest that different species from the same genus respond in different ways to the environmental signals,and the desert adapted species are not as sensitive to change in photoperiod as the other two species.展开更多
phytohemagglutinin(PHA)-induced swelling is widely used to investigate cell-mediated and innate immunity across different vertebrate taxa.However,its physiological mechanism is still an open question due to the comple...phytohemagglutinin(PHA)-induced swelling is widely used to investigate cell-mediated and innate immunity across different vertebrate taxa.However,its physiological mechanism is still an open question due to the complexity of the involved immune components.In the present study,we measured the synchronous variations of PHA response,the proportion of different subtypes of leukocytes,as well as serum bactericidal capacity in circulation blood at 6,12 and 24 h after PHA versus PBS injection in striped hamster,Cricetulus barabensis.First,the results showed that PHA responses reached a peak at 6 h postinjection,then sharply declined at 12 h and 24 h postinjection.Serum bactericidal capacity was higher at 6 h and 12 h than at 24 h.The proportion of different subtypes of leukocytes,as well as the ratio of neutrophils to lymphocytes did not display significant changes across different time points.Second,PHA response was positively correlated with the proportion of neutrophils and serum bactericidal capacity.The proportion of monocytes was negatively correlated with that of eosinophils and neutrophils.The proportion of basophils was negatively correlated with that of lymphocytes.Our results indicate that earlier enhanced PHA response is important for the striped hamster to cope with changing environmental conditions due to its small body mass,and the increased components of innate immunity in circulation blood may contribute to the enhancement of PHA swelling response.展开更多
Ambient temperature considerably affects the physiology and behavior of mammals.Thermosensory and thermoregulatory abilities play an important role in the response to changing ambient temperature in endotherms.However...Ambient temperature considerably affects the physiology and behavior of mammals.Thermosensory and thermoregulatory abilities play an important role in the response to changing ambient temperature in endotherms.However,the molecular mechanisms of behavioral thermoregulation remain poorly understood.Transient receptor potential vanilloid-1(TRPV1)is activated by changes in ambient temperature and is involved in acute thermoregulation.Here,we aimed to determine whether TRPV1 is involved in behavioral thermoregulation in wild rodents by conducting 2 experiments.In the first,42 adult Mongolian gerbils(Meriones unguiculatus;14 per treatment)were randomly assigned to 3 housing temperatures(4,23,and 36℃for 4 weeks.In the second,20 gerbils(10 per treatment)were randomly injected with capsaicin(TRPV1 agonist)or AMG517(TRPV1 antagonist).The results showed a significant decrease in food intake and non-shivering thermogenesis in the gerbils housed at 36℃.Additionally,there was a significant increase in the preference of gerbils housed at 4℃ to low temperatures.The expression of TRPV1 protein in the brown adipose tissue(BAT)and liver was significantly positively correlated with that of protein kinase A(PKA).The expression of TRPV1 and PKA proteins in the BAT was positively correlated with the temperature preference of the gerbils.The gerbils injected with capsaicin preferred significantly lower temperatures than the control group gerbils.These findings suggest that TRPV1 and PKA are involved in behavioral thermoregulation in Mongolian gerbils.展开更多
In the present study,we examined metabolic,morphological and neurochemical changes in male striped hamsters(Cricetulus barabensis)in response to variations in food availability.Males with low and high levels of metabo...In the present study,we examined metabolic,morphological and neurochemical changes in male striped hamsters(Cricetulus barabensis)in response to variations in food availability.Males with low and high levels of metabolic rate(MR:L-MR and H-MR,respectively),defined by their activity MR,were compared.In Experiment 1,36-h food deprivation was found to significantly decrease MR levels,body fat content,mass of small and large intestines,and leptin gene expression in the white adipose tissues in male hamsters.Interestingly,L-MR males displayed decreased MR during both the day and night phases of circadian cycles,whereas H-MR males only showed a decrease in MR during the day(resting phase).These data indicate that individual differences in physical activity were associated with animals’different metabolic responses to food deprivation.In Experiment 2,both groups of males went through a 4-week fasting and re-feeding(re)paradigm.H-re males showed a persistent high level of MR,with decreased body fat content and a trending decrease in leptin mRNA expression,compared to L-re males.Together,our data indicate that male striped hamsters with different levels of physical activity display altered,adaptive changes in response to variations in food availability.The neurochemical involvement of such adaptive changes needs to be further studied.展开更多
Damage of axon and glial scars formation both inhibit nerve regenerative growth during nerve injury.In addition,mechanical stretch at high displacement rates of 10%tensile strain can cause marked nerve injury,it is im...Damage of axon and glial scars formation both inhibit nerve regenerative growth during nerve injury.In addition,mechanical stretch at high displacement rates of 10%tensile strain can cause marked nerve injury,it is important for finding a proper nano biomaterial to repair nerve injury.Nano-hydroxyapatite(n-HA)has excellent biocompatibility and high bioactivity,which is a good candidate for biomedical engineering applications.But the certain mechanism of n-HA on the injured nerve is seldom reported.In this study,we determined the role of n-HA on the mechanical stretch-induced nerve injury at adult rat spine.Mechanical stretch under strain 10%at displacement rates of 60 mm/min can cause marked broken vessels and edema in spinal cord and dorsal root ganglion tissue in haematoxylin-eosin(HE)staining.However,n-HA application can reverse hemorrhage and edema triggered by high rates of 60 mm/min stretch.Moreover,n-HA can promote positive staining of Netrin-1 increase significantly in spinal cord and dorsal root ganglion tested by immunohistochemistry(IHC)staining.In general,our study indicated that n-HA can repair mechanical stretch-induced nerve injury,it may provide a new approach to block injury and accelerate nerve regeneration in future.展开更多
Appropriate mechanical support and excellent osteogenic capability are two essential prerequisites of customized implants for regenerating large-sized cranial bone defect.Although porous bone scaffolds have been widel...Appropriate mechanical support and excellent osteogenic capability are two essential prerequisites of customized implants for regenerating large-sized cranial bone defect.Although porous bone scaffolds have been widely proven to promote bone regeneration,their weak mechanical properties limit the clinical applications in cranioplasty.Herein,we applied two previously developed mineralized collagen-based bone scaffolds(MC),porous MC(pMC)and compact MC(cMC)to construct a biphasic MC composite bone scaffold(bMC)to repair the large-sized cranial bone defect in developing sheep.A supporting frame composed of cMC phase in the shape of tic–tac–toe structure was fabricated first and then embedded in pMC phase.The two phases had good interfacial bond,attributing to the formation of an interfacial zone.The in vivo performance of the bMC scaffold was evaluated by using a cranial bone defect model in 1-month-old sheep.The computed tomography imaging,X-ray scanning and histological evaluation showed that the pMC phase in the bMC scaffold,similar to the pMC scaffold,was gradually replaced by the regenerative bone tissues with comprehensively increased bone mineral density and complete connection of bone bridge in the whole region.The cMC frame promoted new bone formation beneath the frame without obvious degradation,thus providing appropriate mechanical protection and ensuring the structural integrity of the implant.In general,the sheep with bMC implantation exhibited the best status of survival,growth and the repair effect.The biphasic structural design may be a prospective strategy for developing new generation of cranioplasty materials to regenerate cranial bone defect in clinic.展开更多
Rice(Oryza sativa)is one of the most important food crops in the world today,feeding more than one-third of the global population.Therefore.the domestication of rice has always been an international research topic(Gro...Rice(Oryza sativa)is one of the most important food crops in the world today,feeding more than one-third of the global population.Therefore.the domestication of rice has always been an international research topic(Gross and Zhao,2014).When,where,and how rice was cultivated and eventually domesticated has been a hot issue in many research fields such as archaeology,biology,and agronomy(Fuller et al.,2009).展开更多
Landing mechanism tends to rebound and turn over,and the stability time is long when landing on the small celestial body.Its landing performance in different conditions is necessary to be evaluated to guide the landin...Landing mechanism tends to rebound and turn over,and the stability time is long when landing on the small celestial body.Its landing performance in different conditions is necessary to be evaluated to guide the landing.Here,landing performance evaluation is realized by simulation.Key factors affecting the landing performance including cardan element damping,foot anchors,retro-rocket thrust,landing slope angle,and landing attitude are analyzed.A microgravity platform is built to test the landing mechanism,and the consistency between the simulation and the experiment is compared.On the basis of simulation and experiment,some landing suggestions are proposed to improve the landing performance.展开更多
基金Supported by the Project of Building National Bee Industry Technology system(NO.:CARS-45-KXJ20)Support by the Youth Fund of Shandong Academy of Agricultural Science(2014QNM31)+1 种基金the China Agriculture Research System of Sweet Potato(CARS-11-B-06)the Scientific and Technical Innovation Project of Chinese Academy of Agricultural Sciences(ASTIP-IAED-2016-05)
文摘China's bee industry is a small proportion of domestic agriculture with fewer farmers, and the government didn't attach much attention to or give supports to it. Agricultural production sector does not fully recognize the economic value of honeybee pollination. Chinese beekeepers gain profits only from products such as honey, royal jelly and bee pollen. Because of the production mode that aims at gathering and producing more honey while neglecting the health care of bees and the quality of products; export enterprises lack guidance and knowledge in export inspection and quarantine and technical regulations, and thus, the average price of China's bee honey exports is much lower than that of other countries in the world. Meanwhile, in domestic market, given the sustained development of China's macro economy and increasing incomes of residents, people show increasing interests in the health care function of honey. Based on the survey data of honey market in Beijing, Hangzhou, Qingdao, Zhengzhou and Chengdu from 2012 to 2015, the paper analyzes the price feature of China's honey market and its formulation basis, and also compares prices of honey with the same quality in different markets. Moreover, the paper combines data from fixed observation places of honey products production, which is carried out by the economic research group of bee industry in 11 provinces, to discuss reasons for continuous honey price rising in domestic market. Lastly, the paper uses the honey as an example to analyze pricing strategy of agricultural products with health care functions. The paper hold the opinions that the keys to solve the problem that high quality agricultural material couldn't sell in high price and good and bad are mixed in the market, is to build up quality and price mechanism in the processing of raw material purchasing to the terminal market, publicize more products information and superior customer attractiveness on health care effect.
文摘In this study,perovskite-type La_(0.7)Ca_(0.3)Co_(0.3)Fe_(0.6)M_(0.1)O_(3-δ)(M=Cu,Zn)powders were synthesized using a scalable reverse co-precipitation method,presenting them as novel materials for oxygen transport membranes.The comprehensive study covered various aspects including oxygen permeability,crystal structure,conductivity,morphology,CO_(2) tolerance,and long-term regenerative durability with a focus on phase structure and composition.The membrane La_(0.7)Ca_(0.3)Co_(0.3)Fe_(0.6)M_(0.1)O_(3-δ)exhibited high oxygen permeation fluxes,reaching up to 0.88 and 0.64 mL·min^(−1)·cm^(−2) under air/He and air/CO_(2) gradients at 1173 K,respectively.After 1600 h of CO_(2) exposure,the perovskite structure remained intact,showcasing superior CO_(2) resistance.A combination of first principles simulations and experimental measurements was employed to deepen the understanding of Cu/Zn substitution effects on the structure,oxygen vacancy formation,and transport behavior of the membranes.These findings underscore the potential of this highly CO_(2)-tolerant membrane for applications in high-temperature oxygen separation.The enhanced insights into the oxygen transport mechanism contribute to the advancement of next-generation membrane materials.
基金supported by the National Natural Science Foundation of China(Grant Nos.41971009&41503054)the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDA2000300)。
文摘The Hengduan Mountains is in the transitional zone between the Qinghai-Tibet Plateau(QTP)and the YunnanGuizhou Plateau in China,and a key area for elucidating the Quaternary environmental changes in Asia.The paleo-Daocheng ice cap was located on the Shaluli Hilly Plateau in the northeastern Hengduan Mountains,the oldest moraines in the Hengduan Mountains region were found in the ice cap area.Such glacial landforms provide key evidence to study the timing when this area entered the cryosphere with the uplift of the QTP.However,it is difficult to collect suitable glacial boulders from these moraines for traditional terrestrial in-situ cosmogenic nuclide(TCN)exposure dating because of long-term severe moraine degradation.Here,we collected clast samples from the moraine surface and depth profile to constrain the age of the oldest moraine in Kuzhaori(moraine E)using TCN^(10)Be dating technique.The minimum^(10)Be ages of five clast samples from the moraine surface range from 187.4±1.5 to 576.8±4.3 ka,implying that the moraine has been seriously degraded since deposition.Based on the TCN^(10)Be concentrations of the samples from a depth profile and simulations,the exposure-erosion-inheritance history of the profile was obtained.By fitting to the profile^(10)Be concentrations using the chi-square test,the simulations yielded a reliable age of 626.0±52.5 ka for the moraine.Therefore,the oldest moraine(moraine E)in Kuzhaori was most likely formed at about 0.63Ma ago,corresponding to the marine isotope stage(MIS)16.This glaciation represents the maximum Quaternary glaciation after the QTP was elevated into the cryosphere by the Kunlun-Yellow River Tectonic Movement.
基金supported by grants from National Natural Science Foundation of China(Nos.31670417,31870388).
文摘The thermoneutral zone(TNZ)reflects the adaptation of mammals to their natural habitat.However,it remains unclear how TNZ shifts in response to variations in ambient temperature.To test the hypothesis that ambient temperature plays a key role in determining TNZ variations between seasons,we measured metabolic rate,body temperature,and cytochrome c oxidase(COX)activity of several visceral organs in striped hamsters(Cricetulus barabensis)either acclimated to semi-natural conditions over a year,or subjected to a gradual decrease in mean temperature from 30±1°C to-15±1°C.The TNZ range in striped hamsters differed seasonally,with a wider TNZ and a lower lower-critical temperature in winter compared to summer.The hamsters showed a consider-able leftward shift of lower-critical temperature from 30°C to 20°C after the ambient temperature of acclimation from 30°C down to-15°C,whereas the upper-critical temperature of TNZ remainedfixed at 32.5°C.The rest-ing metabolic rate in thermoneutral zone(RMRt),nonshivering thermogenesis(NST),and COX activity of brown adipose tissue,liver,skeletal muscle,brain,and kidneys,increased significantly in hamsters acclimated at lower ambient temperatures.Following acute exposure to 5°C and-15°C,hamsters acclimated to 32.5°C had signifi-cantly lower maximal NST and lower serum thyroid tri-iodothyronine(T3)levels compared to those kept at 23°C.Thesefindings suggest that acclimation to the upper-critical temperature of TNZ impairs the hamsters’thermo-genic capacity to cope with extreme cold temperature.Reduced ambient temperature was mainly responsible for the leftward shift of TNZ in striped hamsters,which reflects the adaptation to cold environments.
基金supported by National Natural Science Foundation of China(No.51572144,81360164 and 81660214)111 Project(No.B17026)Beijing Nova Program(Z161100004916051)。
文摘Large-sized cranial bone defect repair presents a great challenge in the clinic.The ideal cranioplasty materials to realize the functional and cosmetic recovery of the defect must have sufficient mechanical support,excellent biocompatibility,good osseointegration and biodegradability as well.In this study,a high-strength mineralized collagen(MC)bone scaffold was developed with biomimetic composition,microstructure and mechanical properties for the repair of sheep largesized cranial bone defects in comparison with two traditional cranioplasty materials,polymethyl methacrylate and titanium mesh.The compact MC scaffold showed no distinct pore structure and therefore possessed good mechanical properties.The strength and elastic modulus of the scaffold were much higher than those of natural cancellous bone and slightly lower than those of natural compact bone.In vitro cytocompatibility evaluation revealed that the human bone marrow mesenchymal stem cells(hBMSC)had good viability,attachment and proliferation on the compact MC scaffold indicating its excellent biocompatibility.An adult sheep cranial bone defect model was constructed to evaluate the performances of these cranioplasty materials in repairing the cranial bone defects.The results were investigated by gross observation,computed tomography scanning as well as histological assessments.The in vivo evaluations indicated that compact MC scaffold showed notable osteoconductivity and osseointegration with surrounding cranial bone tissues by promoting bone regeneration.Our results suggested that the compact MC scaffold has a promising potential for large-sized cranial bone defect repair.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB26000000)the National Natural Science Foundation of China(Grant Nos.41877427&41730319)+1 种基金the National Basic Research Program of China(Grant No.2015CB953803)the Youth Innovation Promotion Association of Chinese Academy of Sciences(Grant No.2018099)。
文摘South China preserves a rich archaeological record elucidating the evolution of early modern humans during the Late Pleistocene.However,few studies on plant utilization were conducted in this region.We used phytolith analysis from Yahuai Cave,Guangxi,to infer human use of plant resources over the past 30000 years.AMS 14C dating was used to constrain the chronological framework.Results indicate that several economically essential species were present throughout the sequence including Urticineae(cf.Ulmus sp.),which appears in the lower layers of the sequence(Marine Isotope Stage 3 through Heinrich 1);bamboo and palm which appear throughout the sequence,and wild rice which appears in a clear archaeological context dating to 16000 years ago.This is the earliest record of wild rice in South China and a prerequisite for rice domestication.The unique stone tool assemblages,which resemble those in north China as opposed to South China,point to the possibility that humans,seeking refuge from the colder north,brought their tool kit with them and utilized familiar northern taxa.Warmer South China would have served as a refuge for human populations escaping the cold,harsh climate in the north with more ameliorate conditions in the south.
基金This work was funded by grants(no.31670417 and 31070367)from the National Natural Science Foundation of Chinaa grant(pd2013374)from the Department of Education of Zhejiang Province.
文摘The life history of many animals includes periods of food shortage.Two behavioral strategies are involved in small mammals in response to food shortage:an increase in activity behavior,representing the increased foraging or migratory behavior,and a decrease in activity level,serving as a mechanism for conserving energy.However,it is uncertain whether animals adopt both strategies in response to food shortage,and whether hormone and neuroendocrine mechanisms are involved in both strategies.In the present study,changes in behavior and metabolic rate were examined in food-deprived striped hamsters(Cricetulus barabensis).The effects of leptin supplement on activity behavior,metabolic rate and hypothalamic neuropeptide gene expression were also examined.The behavior of food-deprived hamsters significantly changed with photoperiod phases:with increasing activity during the dark phase compared to those fed ad libitum,whereas decreasing activity and simultaneously increasing resting behavior during the light phase.Resting metabolic rate,body mass,and masses of fat depots and digestive tracts significantly decreased in food-deprived hamsters compared with ad libitum controls.Leptin supplement tended to attenuate the increased activity in the dark phase.Gene expression of hypothalamic neuropeptide Y(NPY)was significantly upregulated in food-deprived hamsters,while was significantly attenuated by exogenous leptin.These findings suggest that both behavior strategies are important behavioral adjustments in free-living animals to cope with food shortage.Leptin and hypothalamic NPY gene expression may be involved in the adjustments of physiology and behavior in animals demonstrating a hyperactivity strategy in response to food shortage.
基金The authors would like to thank Dr M.Klingensphor from the Department of Biology,Phillips University,Germany for providing the UCP1 antibody.Thanks to Lina Zhang and Bobin Jing for measuring serum leptin concentrations.Thanks to Gangbin Tang and Jianguo Cui for measuring the UCP1.The study was partly supported by the Joint Project of the Russian Basic Research and the National Natural Science Foundation of China to D.W.and N.V.
文摘Desert hamsters(Phodopus roborovskii)are the least known species in the genus Phodopus with respect to ecology and physiology,and deserve scientific attention,particularly because of their small body size.Here,the responses of energy metabolism and reproductive function to short photoperiods in desert hamsters were investigated.Male and female desert hamsters were acclimated to either long day(LD)(L:D 16:8 h)or short day(SD)photoperiods(L:D 8:16 h)for three months,and then the females were transferred back to an LD photoperiod for a further five months,while at the end of the SD acclimation the males were killed and measurements were taken for serum leptin as well as molecular markers for thermogenesis.We found that like the other two species from the genus Phodopus,the desert hamsters under SD decreased body mass,increased adaptive thermogenesis as indicated by elevated mitochondrial protein content and uncoupling protein-1 content in brown adipose tissue,and suppressed reproduction compared to those under LD.However,different from the other two species,desert hamsters did not show any differences in energy intake or serum leptin concentration between LD and SD.These data suggest that different species from the same genus respond in different ways to the environmental signals,and the desert adapted species are not as sensitive to change in photoperiod as the other two species.
基金This study was supported by a Key Project of Natural Science of the Anhui Province Department of Education,China(KJ2011A114)supported by the State Key Laboratory of Integrated Management of Pest Insects and Rodents,Institute of Zoology,The Chinese Academy of Sciences(ChineseIPM1001)to ZZQ.
文摘phytohemagglutinin(PHA)-induced swelling is widely used to investigate cell-mediated and innate immunity across different vertebrate taxa.However,its physiological mechanism is still an open question due to the complexity of the involved immune components.In the present study,we measured the synchronous variations of PHA response,the proportion of different subtypes of leukocytes,as well as serum bactericidal capacity in circulation blood at 6,12 and 24 h after PHA versus PBS injection in striped hamster,Cricetulus barabensis.First,the results showed that PHA responses reached a peak at 6 h postinjection,then sharply declined at 12 h and 24 h postinjection.Serum bactericidal capacity was higher at 6 h and 12 h than at 24 h.The proportion of different subtypes of leukocytes,as well as the ratio of neutrophils to lymphocytes did not display significant changes across different time points.Second,PHA response was positively correlated with the proportion of neutrophils and serum bactericidal capacity.The proportion of monocytes was negatively correlated with that of eosinophils and neutrophils.The proportion of basophils was negatively correlated with that of lymphocytes.Our results indicate that earlier enhanced PHA response is important for the striped hamster to cope with changing environmental conditions due to its small body mass,and the increased components of innate immunity in circulation blood may contribute to the enhancement of PHA swelling response.
基金This work was supported by the National Natural Science Foundation of China(No.31970417 and 31772461)to DHWthe State Key Laboratory of Integrated Management of Pest Insects and Rodents(Grant No.IPM2004).
文摘Ambient temperature considerably affects the physiology and behavior of mammals.Thermosensory and thermoregulatory abilities play an important role in the response to changing ambient temperature in endotherms.However,the molecular mechanisms of behavioral thermoregulation remain poorly understood.Transient receptor potential vanilloid-1(TRPV1)is activated by changes in ambient temperature and is involved in acute thermoregulation.Here,we aimed to determine whether TRPV1 is involved in behavioral thermoregulation in wild rodents by conducting 2 experiments.In the first,42 adult Mongolian gerbils(Meriones unguiculatus;14 per treatment)were randomly assigned to 3 housing temperatures(4,23,and 36℃for 4 weeks.In the second,20 gerbils(10 per treatment)were randomly injected with capsaicin(TRPV1 agonist)or AMG517(TRPV1 antagonist).The results showed a significant decrease in food intake and non-shivering thermogenesis in the gerbils housed at 36℃.Additionally,there was a significant increase in the preference of gerbils housed at 4℃ to low temperatures.The expression of TRPV1 protein in the brown adipose tissue(BAT)and liver was significantly positively correlated with that of protein kinase A(PKA).The expression of TRPV1 and PKA proteins in the BAT was positively correlated with the temperature preference of the gerbils.The gerbils injected with capsaicin preferred significantly lower temperatures than the control group gerbils.These findings suggest that TRPV1 and PKA are involved in behavioral thermoregulation in Mongolian gerbils.
基金This work was funded by the grants(No.31270458 and 31670417)from the National Natural Science Foundation of Chinapartially supported by grants(no.ChineseIPM1704)from the State Key Laboratory of Integrated Management of Pest Insects and Rodents.
文摘In the present study,we examined metabolic,morphological and neurochemical changes in male striped hamsters(Cricetulus barabensis)in response to variations in food availability.Males with low and high levels of metabolic rate(MR:L-MR and H-MR,respectively),defined by their activity MR,were compared.In Experiment 1,36-h food deprivation was found to significantly decrease MR levels,body fat content,mass of small and large intestines,and leptin gene expression in the white adipose tissues in male hamsters.Interestingly,L-MR males displayed decreased MR during both the day and night phases of circadian cycles,whereas H-MR males only showed a decrease in MR during the day(resting phase).These data indicate that individual differences in physical activity were associated with animals’different metabolic responses to food deprivation.In Experiment 2,both groups of males went through a 4-week fasting and re-feeding(re)paradigm.H-re males showed a persistent high level of MR,with decreased body fat content and a trending decrease in leptin mRNA expression,compared to L-re males.Together,our data indicate that male striped hamsters with different levels of physical activity display altered,adaptive changes in response to variations in food availability.The neurochemical involvement of such adaptive changes needs to be further studied.
基金supported by funds from the National Natural Science Foundation of China(NSFC)Research Grant(31971238,51574246,61871014,11827803,31771019)National Key Research and Development Program(2016YFC1100704,2016YFC1102203)+1 种基金also supported by 111 Project(B13003)International Joint Research Center of Aerospace Biotechnology and Medical Engineering,Ministry of Science and Technology,China.
文摘Damage of axon and glial scars formation both inhibit nerve regenerative growth during nerve injury.In addition,mechanical stretch at high displacement rates of 10%tensile strain can cause marked nerve injury,it is important for finding a proper nano biomaterial to repair nerve injury.Nano-hydroxyapatite(n-HA)has excellent biocompatibility and high bioactivity,which is a good candidate for biomedical engineering applications.But the certain mechanism of n-HA on the injured nerve is seldom reported.In this study,we determined the role of n-HA on the mechanical stretch-induced nerve injury at adult rat spine.Mechanical stretch under strain 10%at displacement rates of 60 mm/min can cause marked broken vessels and edema in spinal cord and dorsal root ganglion tissue in haematoxylin-eosin(HE)staining.However,n-HA application can reverse hemorrhage and edema triggered by high rates of 60 mm/min stretch.Moreover,n-HA can promote positive staining of Netrin-1 increase significantly in spinal cord and dorsal root ganglion tested by immunohistochemistry(IHC)staining.In general,our study indicated that n-HA can repair mechanical stretch-induced nerve injury,it may provide a new approach to block injury and accelerate nerve regeneration in future.
基金financial support from the National Key R&D Program of China(2020YFC1107602)Shandong Province Key R&D Program of China(2019JZZY011106)the National Natural Science Foundation of China(No.81660214,81960238,82160250).
文摘Appropriate mechanical support and excellent osteogenic capability are two essential prerequisites of customized implants for regenerating large-sized cranial bone defect.Although porous bone scaffolds have been widely proven to promote bone regeneration,their weak mechanical properties limit the clinical applications in cranioplasty.Herein,we applied two previously developed mineralized collagen-based bone scaffolds(MC),porous MC(pMC)and compact MC(cMC)to construct a biphasic MC composite bone scaffold(bMC)to repair the large-sized cranial bone defect in developing sheep.A supporting frame composed of cMC phase in the shape of tic–tac–toe structure was fabricated first and then embedded in pMC phase.The two phases had good interfacial bond,attributing to the formation of an interfacial zone.The in vivo performance of the bMC scaffold was evaluated by using a cranial bone defect model in 1-month-old sheep.The computed tomography imaging,X-ray scanning and histological evaluation showed that the pMC phase in the bMC scaffold,similar to the pMC scaffold,was gradually replaced by the regenerative bone tissues with comprehensively increased bone mineral density and complete connection of bone bridge in the whole region.The cMC frame promoted new bone formation beneath the frame without obvious degradation,thus providing appropriate mechanical protection and ensuring the structural integrity of the implant.In general,the sheep with bMC implantation exhibited the best status of survival,growth and the repair effect.The biphasic structural design may be a prospective strategy for developing new generation of cranioplasty materials to regenerate cranial bone defect in clinic.
文摘Rice(Oryza sativa)is one of the most important food crops in the world today,feeding more than one-third of the global population.Therefore.the domestication of rice has always been an international research topic(Gross and Zhao,2014).When,where,and how rice was cultivated and eventually domesticated has been a hot issue in many research fields such as archaeology,biology,and agronomy(Fuller et al.,2009).
基金supported by the National Natural Science Foundation of China(no.U22B2080)the State Key Laboratory of Robotics and System(HIT)(no.SKLRS-2021-KF-14).
文摘Landing mechanism tends to rebound and turn over,and the stability time is long when landing on the small celestial body.Its landing performance in different conditions is necessary to be evaluated to guide the landing.Here,landing performance evaluation is realized by simulation.Key factors affecting the landing performance including cardan element damping,foot anchors,retro-rocket thrust,landing slope angle,and landing attitude are analyzed.A microgravity platform is built to test the landing mechanism,and the consistency between the simulation and the experiment is compared.On the basis of simulation and experiment,some landing suggestions are proposed to improve the landing performance.