BACKGROUND Understanding the impact of early sensory deficits on brain development is essential for understanding developmental processes and developing potential interventions.While previous studies have looked into ...BACKGROUND Understanding the impact of early sensory deficits on brain development is essential for understanding developmental processes and developing potential interventions.While previous studies have looked into the impact of prenatal experiences on language development,there is a lack of research on how these experiences affect early language and brain function development in individuals with sensorineural hearing loss(SNHL).AIM To investigate SNHL effects on early brain development and connectivity in 4-month-olds vs healthy newborns and controls.METHODS The research involved analyzing the functional brain networks of 65 infants,categorized into three groups:28 healthy newborns,224-month-old participants with SNHL,and 15 age-matched healthy participants.The resting-state functional connectivity was measured and compared between the groups using functional near-infrared spectroscopy and graph theory to assess the brain network properties.RESULTS Significant differences were found in resting-state functional connectivity between participants with SNHL and age-matched controls,indicating a developmental lag in brain connectivity for those with SNHL.Surprisingly,SNHL participants showed better connectivity development compared to healthy newborns,with connectivity strengths of 0.13±0.04 for SNHL,0.16±0.08 for controls,and 0.098±0.04 for newborns.Graph theory analysis revealed enhanced global brain network properties for the SNHL group,suggesting higher communication efficiency at 4 months.No significant differences were noted in network properties between 4-month-old SNHL participants and neonates.A unique pattern of central hubs was observed in the SNHL group,with 2 hubs in the left hemisphere compared to 6 in controls.CONCLUSION 4-month-old infants with SNHL have a distinct brain network pattern with efficient long-distance information transmission but less effective local communication compared to age-matched controls.展开更多
The changes in pore structure within soil-rock mixtures under freeze-thaw cycles in cold regions result in strength deterioration,leading to instability and slope failure.However,the existing studies mainly provided q...The changes in pore structure within soil-rock mixtures under freeze-thaw cycles in cold regions result in strength deterioration,leading to instability and slope failure.However,the existing studies mainly provided qualitative analysis of the changes in pore or strength of soil-rock mixture under freeze-thaw cycles.In contrast,few studies focused on the quantitative evaluation of pore change and the relationship between the freeze-thaw strength deterioration and pore change of soil-rock mixture.This study aims to explore the correlation between the micro-pore evolution characteristics and macro-mechanics of a soil-rock mixture after frequent freeze-thaw cycles during the construction and subsequent operation in a permafrost region.The pore characteristics of remolded soil samples with different rock contents(i.e.,25%,35%,45%,and 55%)subjected to various freeze-thaw cycles(i.e.,0,1,3,6,and 10)were quantitatively analyzed using nuclear magnetic resonance(NMR).Shear tests of soil-rock samples under different normal pressures were carried out simultaneously to explore the correlation between the soil strength changes and pore characteristics.The results indicate that with an increase in the number of freeze-thaw cycles,the cohesion of the soil-rock mixture generally decreases first,then increases,and finally decreases;however,the internal friction angle shows no apparent change.With the increase in rock content,the peak shear strength of the soil-rock mixture rises first and then decreases and peaks when the rock content is at 45%.When the rock content remains constant,as the number of freeze-thaw cycles rises,the shear strength of the sample reaches its peak after three freeze-thaw cycles.Studies have shown that with an increase in freeze-thaw cycles,the medium and large pores develop rapidly,especially for pores with a size of 0.2–20μm.Freeze-thaw cycling affects the internal pores of the soil-rock mixture by altering its skeleton and,therefore,impacts its macro-mechanical characteristics.展开更多
Dental stem cells(DSCs), an important source of mesenchymal stem cells(MSCs), can be easily obtained by minimally invasive procedures and have been used for the treatment of various diseases. Classic paradigm attribut...Dental stem cells(DSCs), an important source of mesenchymal stem cells(MSCs), can be easily obtained by minimally invasive procedures and have been used for the treatment of various diseases. Classic paradigm attributed the mechanism of their therapeutic action to direct cell differentiation after targeted migration, while contemporary insights into indirect paracrine effect opened new avenues for the mystery of their actual low engraftment and differentiation ability in vivo. As critical paracrine effectors, DSC-derived extracellular vesicles(DSC-EVs) are being increasingly linked to the positive effects of DSCs by an evolving body of in vivo studies. Carrying bioactive contents and presenting therapeutic potential in certain diseases, DSC-EVs have been introduced as promising treatments. Here, we systematically review the latest in vivo evidence that supports the therapeutic effects of DSC-EVs with mechanistic studies. In addition, current challenges and future directions for the clinical translation of DSC-EVs are also highlighted to call for more attentions to the(Ⅰ) distinguishing features of DSC-EVs compared with other types of MSC-EVs,(Ⅱ)heterogeneity among different subtypes of DSC-derived EVs,(Ⅲ) action modes of DSC-EVs,(Ⅳ) standardization for eligible DSC-EVs and(Ⅴ) safety guarantee for the clinical application of DSC-EVs. The present review would provide valuable insights into the emerging opportunities of DSC-EVs in future clinical applications.展开更多
By statistically analyzing the storm data from the Joint Typhoon Warning Center(JTWC) over the Bengal Bay during the period 1945-2006,it is found that the yearly averaged tropical cyclone(TC) number over the Bay of Be...By statistically analyzing the storm data from the Joint Typhoon Warning Center(JTWC) over the Bengal Bay during the period 1945-2006,it is found that the yearly averaged tropical cyclone(TC) number over the Bay of Bengal is 8.12,which takes place in any month of the whole year;February and March have the fewest TC numbers.The TC numbers begin to increase starting in April and arrive at a peak in October.Differing from TC over the Bay of Bengal,the tropical storms(TS) over the Bay of Bengal has two peak periods,appear in May and in October or November,respectively.With regard to TS intensity,the super severe storm of H4 criterion appeared only one time during the period 1971-1986,but appeared eight times during the period 1987-2006.The monthly change of the original position,the averaged maintaining time,and the longest maintaining time of TS also have two peak values:They appear in April or May and in October or November,respectively.The peak value of the original position in October or November is bigger than that in April or May.The peak value of the average maintaining time and the longest main-taining time of the TS in April or May is bigger than that in October or November.TC landfall path is mostly moving toward northwest or west and accounts for 56.7 percent.The landfall path of the TS differs from that of TC in some respects.The main difference is that the numbers of the northwestern path and un-landfall of TS are less than those for TC,and the numbers of the western path and northeastern path of TS are greater than for TC.Because of the landfall TS in the north-east path has a peak,it and the beginning of the rainy season in Yunnan Province are closely related;it is on Yunnan Province's early summer precipita-tion that they have a great impact.展开更多
In order to clarify the influence of different forest types on soil erosion resistance in water source area of Central Yunnan,with the soils under three different kinds of typical forest in Yizhe watershed as the rese...In order to clarify the influence of different forest types on soil erosion resistance in water source area of Central Yunnan,with the soils under three different kinds of typical forest in Yizhe watershed as the research object,this paper uses field simulation method and principal component analysis to analyze the soil erosion resistance of three kinds of soils. The results show that there is a significant difference in the shear strength of soil among three types of typical forest,and the size of soil shear strength is in the order of Pinus yunnanensis forest land >mixed broadleaf-conifer forest land > eucalyptus forest land. The difference in the soil erosion coefficient among different forests is not significant,and the soil erosion resistance is highest in mixed broadleaf-conifer forest land( 39. 0%),followed by eucalyptus woodland( 37. 0%)and Pinus yunnanensis forest land( 24. 0%). Under heavy rain intensity and long duration of rainfall,the ability of soil under eucalyptus ×Pinus yunnanensis mixed forests to resist disintegration is more obvious. Using principal component analysis to analyze soil erosion resistance of soils under three different forests,we get the comprehensive evaluation model for soil erosion resistance: Y = 0. 763Y1+ 0. 236Y2. The soil erosion resistance is in the order of mixed broadleaf-conifer forest land( 0. 150) > eucalyptus forest land( 0. 127) > Pinus yunnanensis forest land(-0. 079),indicating that the mixed forests have better water loss and soil erosion control effect than pure forests.展开更多
Studies have investigated the effects of androgen deprivation therapy(ADT)use on the incidence and clinical outcomes of coronavirus disease 2019(COVID-19);however,the results have been inconsistent.We searched the Pub...Studies have investigated the effects of androgen deprivation therapy(ADT)use on the incidence and clinical outcomes of coronavirus disease 2019(COVID-19);however,the results have been inconsistent.We searched the PubMed,Medline,Cochrane,Scopus,and Web of Science databases from inception to March 2022;13 studies covering 84003 prostate cancer(PCa)patients with or without ADT met the eligibility criteria and were included in the meta-analysis.We calculated the pooled risk ratios(RRs)with 95%confidence intervals(CIs)to explore the association between ADT use and the infection risk of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)and severity of COVID-19.After synthesizing the evidence,the pooled RR in the SARS-CoV-2 positive group was equal to 1.17,and the SARS-CoV-2 positive risk in PCa patients using ADT was not significantly different from that in those not using ADT(P=0.544).Moreover,no significant results concerning the beneficial effect of ADT on the rate of intensive care unit admission(RR=1.04,P=0.872)or death risk(RR=1.23,P=0.53)were found.However,PCa patients with a history of ADT use had a markedly higher COVID-19 hospitalization rate(RR=1.31,P=0.015)than those with no history of ADT use.These findings indicate that ADT use by PCa patients is associated with a high risk of hospitalization during infection with SARS-CoV-2.A large number of high quality studies are needed to confirm these results.展开更多
The changes in various states of water in ursolic acid(UA)loaded chitosan nanoparticles were assessed using lowfield nuclear magnetic resonance(LF-NMR)during microwave freeze drying(MFD)process,and six thin-layer mode...The changes in various states of water in ursolic acid(UA)loaded chitosan nanoparticles were assessed using lowfield nuclear magnetic resonance(LF-NMR)during microwave freeze drying(MFD)process,and six thin-layer models were applied to simulate the drying kinetics.UA nanoparticles were dried at different microwave power densities(1 W/g,2 W/g and 4 W/g).The results showed that three water fractions with different transverse relaxation times(T_(2))were detected in fresh UA nanoparticles.The T_(2)relaxation time of water decreased significantly with drying time at different microwave power densities.And the mutual migration and transformation of water in different states during the drying process of chitosan nanoparticles occurred.Furthermore,mathematical model analysis showed that the Page model provided the best description during the process of UA nanoparticle dried by MFD.The Page model can better simulate the drying kinetics of chitosan nanoparticles dried by MFD,and LF-NMR technology can monitor the changes in water status of UA nanoparticles.The results revealed that LF-NMR can monitor the changes of water in UA nanoparticles during the drying process.展开更多
In order to reduce the energy consumption of freeze drying(FD),microwave freeze drying(MFD)can be used to dry Chinese yam.Porosity is a critical factor influencing transport mechanism,and can be considered as an impor...In order to reduce the energy consumption of freeze drying(FD),microwave freeze drying(MFD)can be used to dry Chinese yam.Porosity is a critical factor influencing transport mechanism,and can be considered as an important index to reflect the changes of structure of MFD foods.In this study,the changes of pore structure during the process of MFD Chinese yam were investigated by SEM and mercury porosimetry.The results showed that some closed pores could transform to open pores in drying process,and the open porosity showed a rising trend throughout the drying process.The pore size distribution range was about 10 nm to 10^(6) nm throughout the drying process.In the early stage of drying,the pore size was mainly in the range of 10-10^(4) nm,and then the pore size and the number of pores reduced.In the middle and late drying stages,the size of large pores increased again.展开更多
In order to explore the effects of different pretreatments on the pore structure of Chinese yam during Microwave Freeze Drying(MFD),the samples were treated by typical drying pretreatments including osmosis,blanching ...In order to explore the effects of different pretreatments on the pore structure of Chinese yam during Microwave Freeze Drying(MFD),the samples were treated by typical drying pretreatments including osmosis,blanching and ultrasound,and compared with the untreated samples.The results showed that the pretreatment had significant impacts on the porosity of MFD Chinese yam.Ultrasonic pretreatment could obtain the highest open porosity,and the internal pore network structure of the material showed a uniform sponge shape.The shape of pores obtained by blanching pretreatment was the most irregular.The pore network structure obtained by different pretreatments could result in various product texture and rehydration,which implied that pretreatment methods should be carefully selected according to actual requirements.All these pretreatments could improve the open porosity of MFD Chinese yam,which result in a better rehydration capability.Among them,ultrasonic treatment is worth further investigating.展开更多
Yellow maize as raw materials,hot air drying was used to reduce moisture content,and the tempering was implemented after drying.This study aimed to investigate the effects of hot air drying temperature and tempering t...Yellow maize as raw materials,hot air drying was used to reduce moisture content,and the tempering was implemented after drying.This study aimed to investigate the effects of hot air drying temperature and tempering time on the properties of maize starch.The wet milling was used to extract maize starch.Starch yield,protein content,amylose and amylopectin content,transparency and coagulation,solubility index and swelling power,color,pasting properties,and gelatinization properties were researched.The results showed that when the hot air temperature increased,the properties such as starch yield,amylopectin content,transparency,solubility,swelling power,whiteness decreased,and properties such as protein content and amylose content,coagulation,gelatinization temperature increased.Compared to drying temperature,tempering time has a less remarkable effect on the maize starch properties.The maize starch with better whiteness,solubility,swelling power could be obtained by adjusting tempering time.展开更多
Marfan syndrome is a systemic connective tissu disease that could affect the cardiovascular system and eventually lead to heart enlargement an heart failure with high mortality, mainly due t progressive heart failure ...Marfan syndrome is a systemic connective tissu disease that could affect the cardiovascular system and eventually lead to heart enlargement an heart failure with high mortality, mainly due t progressive heart failure and/or sudden cardia death caused by malignant arrhythmia. Here w report that a patient received a cardiac resyn chronization therapy-defibrillator (CRT-D) with pre-monitor function for heart failure and ex perienced obvious improvements in his cardia function. Postoperative follow-up showed that th patient had reduced morbidity and hospitalizatio for heart failure, and also experienced improve quality of life.展开更多
Superconductivity in crystals without inversion symmetry has received extensive attention due to its unconventional pairing and possible nontrivial topological properties.Using first-principles calculations,we systemi...Superconductivity in crystals without inversion symmetry has received extensive attention due to its unconventional pairing and possible nontrivial topological properties.Using first-principles calculations,we systemically study the electronic structure of noncentrosymmetric superconductors A_(2)Cr_(3)As_(3)(A=Na,K,Rb,and Cs).展开更多
基金Supported by the National Social Science Foundation,No.18BY0911.
文摘BACKGROUND Understanding the impact of early sensory deficits on brain development is essential for understanding developmental processes and developing potential interventions.While previous studies have looked into the impact of prenatal experiences on language development,there is a lack of research on how these experiences affect early language and brain function development in individuals with sensorineural hearing loss(SNHL).AIM To investigate SNHL effects on early brain development and connectivity in 4-month-olds vs healthy newborns and controls.METHODS The research involved analyzing the functional brain networks of 65 infants,categorized into three groups:28 healthy newborns,224-month-old participants with SNHL,and 15 age-matched healthy participants.The resting-state functional connectivity was measured and compared between the groups using functional near-infrared spectroscopy and graph theory to assess the brain network properties.RESULTS Significant differences were found in resting-state functional connectivity between participants with SNHL and age-matched controls,indicating a developmental lag in brain connectivity for those with SNHL.Surprisingly,SNHL participants showed better connectivity development compared to healthy newborns,with connectivity strengths of 0.13±0.04 for SNHL,0.16±0.08 for controls,and 0.098±0.04 for newborns.Graph theory analysis revealed enhanced global brain network properties for the SNHL group,suggesting higher communication efficiency at 4 months.No significant differences were noted in network properties between 4-month-old SNHL participants and neonates.A unique pattern of central hubs was observed in the SNHL group,with 2 hubs in the left hemisphere compared to 6 in controls.CONCLUSION 4-month-old infants with SNHL have a distinct brain network pattern with efficient long-distance information transmission but less effective local communication compared to age-matched controls.
基金supported by the National Natural Science Foundation of China(Nos.42071100,42271144)the Shaanxi Qin Chuangyuan"Scientists+Engineers"Team Construction Project(No.2022KXJ-086).
文摘The changes in pore structure within soil-rock mixtures under freeze-thaw cycles in cold regions result in strength deterioration,leading to instability and slope failure.However,the existing studies mainly provided qualitative analysis of the changes in pore or strength of soil-rock mixture under freeze-thaw cycles.In contrast,few studies focused on the quantitative evaluation of pore change and the relationship between the freeze-thaw strength deterioration and pore change of soil-rock mixture.This study aims to explore the correlation between the micro-pore evolution characteristics and macro-mechanics of a soil-rock mixture after frequent freeze-thaw cycles during the construction and subsequent operation in a permafrost region.The pore characteristics of remolded soil samples with different rock contents(i.e.,25%,35%,45%,and 55%)subjected to various freeze-thaw cycles(i.e.,0,1,3,6,and 10)were quantitatively analyzed using nuclear magnetic resonance(NMR).Shear tests of soil-rock samples under different normal pressures were carried out simultaneously to explore the correlation between the soil strength changes and pore characteristics.The results indicate that with an increase in the number of freeze-thaw cycles,the cohesion of the soil-rock mixture generally decreases first,then increases,and finally decreases;however,the internal friction angle shows no apparent change.With the increase in rock content,the peak shear strength of the soil-rock mixture rises first and then decreases and peaks when the rock content is at 45%.When the rock content remains constant,as the number of freeze-thaw cycles rises,the shear strength of the sample reaches its peak after three freeze-thaw cycles.Studies have shown that with an increase in freeze-thaw cycles,the medium and large pores develop rapidly,especially for pores with a size of 0.2–20μm.Freeze-thaw cycling affects the internal pores of the soil-rock mixture by altering its skeleton and,therefore,impacts its macro-mechanical characteristics.
基金funded by the National Natural Science Foundation of China (81922038, 81870361, 81671816)China Postdoctoral Innovation Science Foundation (BX20200254)+3 种基金National Key R&D Program of China (2019YFA0210500)Applied Basic Research Project of Wuhan Municipal Science and Technology Bureau (2020020601012249)Hubei Natural Science Foundation Outstanding Young Talents Project (2020CFA068)China Postdoctoral Science Foundation (2021M692474)
文摘Dental stem cells(DSCs), an important source of mesenchymal stem cells(MSCs), can be easily obtained by minimally invasive procedures and have been used for the treatment of various diseases. Classic paradigm attributed the mechanism of their therapeutic action to direct cell differentiation after targeted migration, while contemporary insights into indirect paracrine effect opened new avenues for the mystery of their actual low engraftment and differentiation ability in vivo. As critical paracrine effectors, DSC-derived extracellular vesicles(DSC-EVs) are being increasingly linked to the positive effects of DSCs by an evolving body of in vivo studies. Carrying bioactive contents and presenting therapeutic potential in certain diseases, DSC-EVs have been introduced as promising treatments. Here, we systematically review the latest in vivo evidence that supports the therapeutic effects of DSC-EVs with mechanistic studies. In addition, current challenges and future directions for the clinical translation of DSC-EVs are also highlighted to call for more attentions to the(Ⅰ) distinguishing features of DSC-EVs compared with other types of MSC-EVs,(Ⅱ)heterogeneity among different subtypes of DSC-derived EVs,(Ⅲ) action modes of DSC-EVs,(Ⅳ) standardization for eligible DSC-EVs and(Ⅴ) safety guarantee for the clinical application of DSC-EVs. The present review would provide valuable insights into the emerging opportunities of DSC-EVs in future clinical applications.
文摘By statistically analyzing the storm data from the Joint Typhoon Warning Center(JTWC) over the Bengal Bay during the period 1945-2006,it is found that the yearly averaged tropical cyclone(TC) number over the Bay of Bengal is 8.12,which takes place in any month of the whole year;February and March have the fewest TC numbers.The TC numbers begin to increase starting in April and arrive at a peak in October.Differing from TC over the Bay of Bengal,the tropical storms(TS) over the Bay of Bengal has two peak periods,appear in May and in October or November,respectively.With regard to TS intensity,the super severe storm of H4 criterion appeared only one time during the period 1971-1986,but appeared eight times during the period 1987-2006.The monthly change of the original position,the averaged maintaining time,and the longest maintaining time of TS also have two peak values:They appear in April or May and in October or November,respectively.The peak value of the original position in October or November is bigger than that in April or May.The peak value of the average maintaining time and the longest main-taining time of the TS in April or May is bigger than that in October or November.TC landfall path is mostly moving toward northwest or west and accounts for 56.7 percent.The landfall path of the TS differs from that of TC in some respects.The main difference is that the numbers of the northwestern path and un-landfall of TS are less than those for TC,and the numbers of the western path and northeastern path of TS are greater than for TC.Because of the landfall TS in the north-east path has a peak,it and the beginning of the rainy season in Yunnan Province are closely related;it is on Yunnan Province's early summer precipita-tion that they have a great impact.
基金Supported by Research Project of Yunnan Provincial Department of Education(2013Y114)Applied Basic Research Projects of Yunnan Province(2012FD028)+1 种基金Key Disciplines(Ecology) Project of Yunnan Education Department(05000511311)Research Starting Capital Project of Southwest Forestry University(111168)
文摘In order to clarify the influence of different forest types on soil erosion resistance in water source area of Central Yunnan,with the soils under three different kinds of typical forest in Yizhe watershed as the research object,this paper uses field simulation method and principal component analysis to analyze the soil erosion resistance of three kinds of soils. The results show that there is a significant difference in the shear strength of soil among three types of typical forest,and the size of soil shear strength is in the order of Pinus yunnanensis forest land >mixed broadleaf-conifer forest land > eucalyptus forest land. The difference in the soil erosion coefficient among different forests is not significant,and the soil erosion resistance is highest in mixed broadleaf-conifer forest land( 39. 0%),followed by eucalyptus woodland( 37. 0%)and Pinus yunnanensis forest land( 24. 0%). Under heavy rain intensity and long duration of rainfall,the ability of soil under eucalyptus ×Pinus yunnanensis mixed forests to resist disintegration is more obvious. Using principal component analysis to analyze soil erosion resistance of soils under three different forests,we get the comprehensive evaluation model for soil erosion resistance: Y = 0. 763Y1+ 0. 236Y2. The soil erosion resistance is in the order of mixed broadleaf-conifer forest land( 0. 150) > eucalyptus forest land( 0. 127) > Pinus yunnanensis forest land(-0. 079),indicating that the mixed forests have better water loss and soil erosion control effect than pure forests.
基金This study was supported by the National Natural Science Foundation of China(81972831 and 31800787)the Natural Science Foundation of Liaoning Province(502722)+4 种基金the“Seedling”Project of Young Scientific and Technological Talents of Liaoning Education Department(LR2019008)the United Fund of the Second Hospital of Dalian Medical University and Dalian Institute of Chemical Physics,Chinese Academy of Sciences(UF-QN-202004)the Dalian High-level Talents Innovation Support Program(2019RQ014)the Doctoral Research Startup Foundation of the Second Hospital of Dalian Medical University(DY2Y201704)the Young Reserve Talent Project of the Second Hospital of Dalian Medical University(dy2yhbrc202010).
文摘Studies have investigated the effects of androgen deprivation therapy(ADT)use on the incidence and clinical outcomes of coronavirus disease 2019(COVID-19);however,the results have been inconsistent.We searched the PubMed,Medline,Cochrane,Scopus,and Web of Science databases from inception to March 2022;13 studies covering 84003 prostate cancer(PCa)patients with or without ADT met the eligibility criteria and were included in the meta-analysis.We calculated the pooled risk ratios(RRs)with 95%confidence intervals(CIs)to explore the association between ADT use and the infection risk of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)and severity of COVID-19.After synthesizing the evidence,the pooled RR in the SARS-CoV-2 positive group was equal to 1.17,and the SARS-CoV-2 positive risk in PCa patients using ADT was not significantly different from that in those not using ADT(P=0.544).Moreover,no significant results concerning the beneficial effect of ADT on the rate of intensive care unit admission(RR=1.04,P=0.872)or death risk(RR=1.23,P=0.53)were found.However,PCa patients with a history of ADT use had a markedly higher COVID-19 hospitalization rate(RR=1.31,P=0.015)than those with no history of ADT use.These findings indicate that ADT use by PCa patients is associated with a high risk of hospitalization during infection with SARS-CoV-2.A large number of high quality studies are needed to confirm these results.
基金supported by the National Natural Science Foundation of China under the contract of(Grant No.32172352)the leading talents of science and technology in the Central Plain of China(Grant No.234200510020).
文摘The changes in various states of water in ursolic acid(UA)loaded chitosan nanoparticles were assessed using lowfield nuclear magnetic resonance(LF-NMR)during microwave freeze drying(MFD)process,and six thin-layer models were applied to simulate the drying kinetics.UA nanoparticles were dried at different microwave power densities(1 W/g,2 W/g and 4 W/g).The results showed that three water fractions with different transverse relaxation times(T_(2))were detected in fresh UA nanoparticles.The T_(2)relaxation time of water decreased significantly with drying time at different microwave power densities.And the mutual migration and transformation of water in different states during the drying process of chitosan nanoparticles occurred.Furthermore,mathematical model analysis showed that the Page model provided the best description during the process of UA nanoparticle dried by MFD.The Page model can better simulate the drying kinetics of chitosan nanoparticles dried by MFD,and LF-NMR technology can monitor the changes in water status of UA nanoparticles.The results revealed that LF-NMR can monitor the changes of water in UA nanoparticles during the drying process.
基金This project was financially supported by the National Natural Science Foundation of China(No.31671907)the Natural Science Foundation of Henan Province(No.182300410062)The authors also thank the support of the Program for Science and Technology Innovation Team in Universities of Henan Province(No.16IRTSTHN009).
文摘In order to reduce the energy consumption of freeze drying(FD),microwave freeze drying(MFD)can be used to dry Chinese yam.Porosity is a critical factor influencing transport mechanism,and can be considered as an important index to reflect the changes of structure of MFD foods.In this study,the changes of pore structure during the process of MFD Chinese yam were investigated by SEM and mercury porosimetry.The results showed that some closed pores could transform to open pores in drying process,and the open porosity showed a rising trend throughout the drying process.The pore size distribution range was about 10 nm to 10^(6) nm throughout the drying process.In the early stage of drying,the pore size was mainly in the range of 10-10^(4) nm,and then the pore size and the number of pores reduced.In the middle and late drying stages,the size of large pores increased again.
基金The authors acknowledge that this work was financially supported by the National Natural Science Foundation of China(Contract No.31671907 and No.31972207).
文摘In order to explore the effects of different pretreatments on the pore structure of Chinese yam during Microwave Freeze Drying(MFD),the samples were treated by typical drying pretreatments including osmosis,blanching and ultrasound,and compared with the untreated samples.The results showed that the pretreatment had significant impacts on the porosity of MFD Chinese yam.Ultrasonic pretreatment could obtain the highest open porosity,and the internal pore network structure of the material showed a uniform sponge shape.The shape of pores obtained by blanching pretreatment was the most irregular.The pore network structure obtained by different pretreatments could result in various product texture and rehydration,which implied that pretreatment methods should be carefully selected according to actual requirements.All these pretreatments could improve the open porosity of MFD Chinese yam,which result in a better rehydration capability.Among them,ultrasonic treatment is worth further investigating.
基金This work was financially supported by the National Natural Science Foundation of China(Grant No.31271972,No.31671907,No.52006109)and the University Science and Technology Innovation Team Support Plan of Henan Province of China in 2016(16IRTSTHN009).
文摘Yellow maize as raw materials,hot air drying was used to reduce moisture content,and the tempering was implemented after drying.This study aimed to investigate the effects of hot air drying temperature and tempering time on the properties of maize starch.The wet milling was used to extract maize starch.Starch yield,protein content,amylose and amylopectin content,transparency and coagulation,solubility index and swelling power,color,pasting properties,and gelatinization properties were researched.The results showed that when the hot air temperature increased,the properties such as starch yield,amylopectin content,transparency,solubility,swelling power,whiteness decreased,and properties such as protein content and amylose content,coagulation,gelatinization temperature increased.Compared to drying temperature,tempering time has a less remarkable effect on the maize starch properties.The maize starch with better whiteness,solubility,swelling power could be obtained by adjusting tempering time.
文摘Marfan syndrome is a systemic connective tissu disease that could affect the cardiovascular system and eventually lead to heart enlargement an heart failure with high mortality, mainly due t progressive heart failure and/or sudden cardia death caused by malignant arrhythmia. Here w report that a patient received a cardiac resyn chronization therapy-defibrillator (CRT-D) with pre-monitor function for heart failure and ex perienced obvious improvements in his cardia function. Postoperative follow-up showed that th patient had reduced morbidity and hospitalizatio for heart failure, and also experienced improve quality of life.
基金This work has been supported by the NSFC(Nos.11874137,11574265,and 11774309)the 973 project(Nos.2014CB648400 and 2016YFA0300402).
文摘Superconductivity in crystals without inversion symmetry has received extensive attention due to its unconventional pairing and possible nontrivial topological properties.Using first-principles calculations,we systemically study the electronic structure of noncentrosymmetric superconductors A_(2)Cr_(3)As_(3)(A=Na,K,Rb,and Cs).