The so-called 'negative difference effect'(NDE) was often defined by the increasing rate of hydrogen evolution from magnesium(Mg) surface under anodic polarization.In this work,a series of electrochemical test...The so-called 'negative difference effect'(NDE) was often defined by the increasing rate of hydrogen evolution from magnesium(Mg) surface under anodic polarization.In this work,a series of electrochemical tests and microstructure observations were performed to provide an evidence that the NDE of Mg-Li alloys can be retarded by increasing lithium content.Potentiostatic,galvanostatic and potentiodynamic polarization experiments using Mg-xLi(x=4,7.5 and 14 wt%) alloys electrodes indicated that Mg-4 Li alloy maintained the enhancing NDE prior to anodic dissolution as that of conventional Mg alloys.However,the emergence of β-Li phase weakened the NDE of duplex Mg-7.5 Li alloy at a low anodic current density,but it was still enhanced apparently after a high applied anodic value(more than 2 mA/cm^2).The surface observations,including the plane and cross-sectional morphologies,confirmed that the cracked surface film derived from the anodic dissolution resulted in the catalytic activity of NDE for Mg-4 Li and Mg-7.5 Li alloys.Furthermore,the NDE of Mg-14 Li alloy was suppressed obviously after a prior applied anodic polarization,which was attributed to the persistent and integrated surface film which endured a higher level of applied anodic potential and current.展开更多
In comparison with the ITRF2000 model, the ITRF2005 model represents a significant improvement in solution generation, datum definition and realization. However, these improvements cause a frame difference between the...In comparison with the ITRF2000 model, the ITRF2005 model represents a significant improvement in solution generation, datum definition and realization. However, these improvements cause a frame difference between the ITRF2000 and ITRF2005 models, which may impact GNSS data processing. To quantify this im- pact, the differences of the GNSS results obtained using the two models, including station coordinates, base- line length and horizontal velocity field, were analyzed. After transformation, the differences in position were at the millimeter level, and the differences in baseline length were less than 1 ram. The differences in the hori- zontal velocity fields decreased with as the study area was reduced. For a large region, the differences in these value were less than 1 mm/a, with a systematic difference of approximately 2 degrees in direction, while for a medium-sized region, the differences in value and direction were not significant.展开更多
There is usually source effect in the field work of controlled-source audio-frequency magnetotelluric method.Source effect is a thorny problem during field working,data processing and interpretation.Therefore,it is ve...There is usually source effect in the field work of controlled-source audio-frequency magnetotelluric method.Source effect is a thorny problem during field working,data processing and interpretation.Therefore,it is very important for the results of field prospecting to model source effect and summarize its influence rules.Based on the previous research,the authors use 3D finite difference method to simulate the electromagnetic field and set different anomaly situation to study the source effect in near-field measurement,then conclude the influence rules of source effect.Simulations provide the reference for the actual field work and data processing to correct the influence of source effect,so the information of the underground will be more approaching to the real.展开更多
The English vocabulary study is a very complicated process,affected by lots of factors.This article will analyze several important individual differences among learners,such as,learning style,gender and learning strat...The English vocabulary study is a very complicated process,affected by lots of factors.This article will analyze several important individual differences among learners,such as,learning style,gender and learning strategy,exploring the most effective ways to expand English vocabulary.展开更多
In the present paper two contents are enclosed .First ,the Fourier analysis approach of the dispersion relation and group velocity effect of finite difference schemes is discussed.the defects of the approach is pointe...In the present paper two contents are enclosed .First ,the Fourier analysis approach of the dispersion relation and group velocity effect of finite difference schemes is discussed.the defects of the approach is pointed out and the correction is made;Second,a new systematic analysis method -remaider -effect analysis (abbr.REAM)is proposed by means of the modified partial differential equations (abbr MPDE)of finite difference schemes.The analysis is based on the synthetical study of the rational dispersion-and dissipation relations of finite difference schemes.And the method clearly possesses constructivity展开更多
Framework definitions of earlier informally used notions of effect and phenomenon are proposed, examples of their role in developing mathematics are given. Phenomena of singular cycle and deepening boundary layer in t...Framework definitions of earlier informally used notions of effect and phenomenon are proposed, examples of their role in developing mathematics are given. Phenomena of singular cycle and deepening boundary layer in the theory of singularly perturbed differential equations and ancient popular synergetic process described by system of random difference equations are presented.展开更多
BACKGROUND： Prenatal stress has been shown to inhibit cell proliferation in the dentate gyrus and hippocampus, reduce hippocampal volume, and cause neuronal loss and oxidative damage in the hippocampus of offspring r...BACKGROUND： Prenatal stress has been shown to inhibit cell proliferation in the dentate gyrus and hippocampus, reduce hippocampal volume, and cause neuronal loss and oxidative damage in the hippocampus of offspring rats, but the sexual difference of the effects on offsprings is seldom referred to. OBJECTIVE： To observe the effect of prenatal stress to adult pregnant rats on expression of extracellular signal-regulated kinases （ERK） in hippocampus of the offspring rats of different genders. DESIGN ： A randomized and control animal experiment.SETTING： Department of Physiology and Pathophysiology, School of Medicine, Xi＇an Jiaotong University. MATERIALS ： The experiments were carried out in the Key Laboratory of Environment and Gene Related Diseases （Xi＇an Jiaotong University）, Ministry of Education between October 2005 and March 2006. Fifteen female and five male adult Sprague-Dawley rats were adopted. Female rats weighing 230-250 g and male rats weighing 280-350 g were used. METHODS： The virgin female rats were placed overnight with adult male rats （3：1） for mating. A total of twelve pregnant rats were randomly assigned to prenatal stress group （PNS group, n=6） and control group （n=6）. The pregnant rats of the PNS group were exposed to restraint stress on days 14-20 of pregnancy three times a day, 45 minutes for each time . The restraint device was a transparent plastic tube （6.8 cm in diameter） with air holes for breathing and closed end. The length could be adjusted to accommodate the size of the animals. To prevent habituation of animals to the daily procedure, restraint periods were randomly shifted within certain time periods （8：00-11：00, 11：00-14：00, and 16：00-19：00）. After birth, offsprings of all groups were culled to 8-10 litters in each group and housed in the same animal room, and kept together with their biologic mothers. The pregnant rats of the control group were left undisturbed. On day 21, after all the offspring were weaned, male and female pups were separated and housed four in each cage respectively until test at 30 days of age. At the end of postnatal day 30, one male and female offspring rats from the same dam were selected with a random choice and a total of 24 animals from 12 different dams were used. The experimental rats were sacrificed by decapitation under anesthesia. Bilateral hippocampal tissues were isolated and homogenized in cold condition. Alkaline carbonate buffer （BCA） method was used to detect the concentration of extracellular signal-regulated kinases （ERK）, then mixed with loading buffer, the constant voltage was 100 V. Finally, BCIP/NBT staining and electrDphoresis were performed, the absorbance （A） value for the bands was detected with the Bandscan analytical software, and the expression of ERK in hippocampus of offspring rats of different genders in each group was quantitatively analyzed. MAIN OUTCOME MEASURES： The level of ERK expression in hippocampus of offspring rats of different genders in each group was observed.RESULTS： All the 24 offspring rats were involved in the analysis of results. ① The staining results of ERP activity in the extract of brain tissue detected with Western blotting technique and specific antibody analysis showed that the ERP in hippocampus of offspring rats had two subtypes of ERK-1 and ERK-2, and the latter was the main type.② Standardized by the average A value in the control group, the quantitative data of the general A value of total ERK showed that the expression of ERK-2 in hippocampus of female offspring rats was obviously higher in the PNS group than in the control group （A value： 126±6.76,100±4.89,P〈 0.01）. ③The expression of ERK-2 had no obvious difference between the female and male offspring rats in the control group.④ The expression of ERK-2 in hippocampus of male offspring rats was a little higher in the PNS group than in the control group （A value： 104±6.27,102±5.48,P 〉 0.05）. CONCLUSION ： PNS significantly affects the increase of ERK expression in hippocampus of female offspring rats, but has no obvious influence on that of male ones.展开更多
Objective: to explore the best surgical treatment of appendicitis in clinical treatment. Methods: appendicitis patients treated with surgery in our hospital from March 2019 to February 2021 were included in the study....Objective: to explore the best surgical treatment of appendicitis in clinical treatment. Methods: appendicitis patients treated with surgery in our hospital from March 2019 to February 2021 were included in the study. According to the different operations selected, 63 cases were divided into the laparoscopic operation group and 61 cases were divided into the laparotomy operation group. The clinical effects of patients treated with different operations were compared. Results: (1) there were significant differences in the amount of bleeding, treatment time, exhaust time, ambulation time, and hospitalization time between the two groups (P<0.05, t=2.055, 2.197, 2.734, 1.935, 2.393). (2) Analysis of postoperative complications in two groups. The total incidence of complications between groups was 3.17% (2 cases) and 22.95% (14 cases), respectively, and the difference was significant (P < 0.05, χ2 =3.771). Conclusion: laparoscopic surgery is a good choice for appendicitis patients with less complication.展开更多
Objective To investigate the effect of gender differences in distal femoral geometry on the clinical outcomes of total knee arthroplasty (TKA).Methods From March 2003 to October 2006,213 cases with 294 osteoarthritic ...Objective To investigate the effect of gender differences in distal femoral geometry on the clinical outcomes of total knee arthroplasty (TKA).Methods From March 2003 to October 2006,213 cases with 294 osteoarthritic knees who展开更多
Objective To observe postoperative effect of electroacupuncture（EA） of different frequencies in acupuncture anesthesia combined with drugs on patients undergoing thyroid surgery.Methods One hundred and twenty patien...Objective To observe postoperative effect of electroacupuncture（EA） of different frequencies in acupuncture anesthesia combined with drugs on patients undergoing thyroid surgery.Methods One hundred and twenty patients undergoing thyroid surgery were randomly divided into a 2Hz electroacupuncture anesthesia group（group A）,a 100 Hz electroacupuncture anesthesia group（group B）,a 2Hz/100 Hz electroacupuncture anesthesia group（group C） and a cervical plexus block group（group D） in accordance with the random number table method,with 30 patients in each group.In group A,group B and group C,electroacupuncture was applied at bilateral Futu（扶突 LI 18）,Hegu（合谷 LI 4） and Neiguan（内关 PC 6） at frequencies of 2 Hz,100 Hz and 2 Hz/100 Hz respectively for 30 min.The needles were retained till the end of the surgery.Dolantin and atropine were intramuscularly injected In group D,bilateral cervical plexus block was produced with a mixture of1%lidocaine and 0.375%bupivicaine.Before surgery,pain threshold and threshold of pain tolerance were determined;during surgery,the duration of surgery was recorded;and after surgery,QOLS（Quality Of Life Score） and PHS（Prince-Henry Score） were assessed.Results PHS in group A,group B and group C were lower than that in group D,respectively（0.20±0.41,0.17±0.38,0.10±0.31 vs 0.40±0.50,P〈0.01）,and PHS in group C was lower than those in group A and group B,respectively（both P〈0.01）.QOLS in group A,group B and group C were higher than that in group D,respectively（9.97±1.07,9.97±2.27,10.40±1.45 vs 9.73±1.41,P〈0.05,P〈0.01）,and QOLS in group C was higher than those in group A and group B,respectively（both P〈0.05）.Conclusion Acupuncture anesthesia combined with drugs has better postoperative effect than drug anesthesia.Electroacupuncture of different frequencies can significantly improve general quality of life of patients,so patients recover well after thyroid surgery.As patients in group C suffered from the slightest pain with the highest quality of life,they recovered best within the shortest time.Electroacupuncture at frequency of 2 Hz/100 Hz can better play postoperative analgesic effect.展开更多
Rural-urban land conversion is a universal phenomenon in the rapid process of economic development and urban growth.The welfare of farmers who lost their farmland attracted a widespread concern within the society and ...Rural-urban land conversion is a universal phenomenon in the rapid process of economic development and urban growth.The welfare of farmers who lost their farmland attracted a widespread concern within the society and academia.However,further research about differentiated policies according to the characteristics of different farmer groups is still need to be conducted.This article divides the land-lost farmers into three age groups:younger than 45,45-65,and more than 65.It proposes a welfare index system including eight functional areas based on different age groups of affected farmers,taking four districts of Wuhan City as case study area.Fuzzy mathematics method is used to derive the aggregated welfare effect index.Our analysis show that the overall welfare levels of land-lost farmers of all age groups declined,but with a varying degree,with the level of welfare in those farmers who are 45-65 years old,younger than 45 years old,and older than 65 years old decreased by 18.7%,16.6%,and 12.7%,respectively.The direction and degree of effects on the functional activity index varies among different groups.Economic conditions,living environment,health,and social participation of all age groups decrease while social security and housing conditions increase.On the other hand,development opportunities,social communication,and leisure have different changing directions in different age stages.These results call for differentiated and tailor-made compensation policies for land-lost farmers,towards improving the welfare levels of all farmers and reduce the disparity among them.展开更多
Asthma is a common chronic inflammatory disorder that is more prevalent in children than in adults.China has seen an increasing prevalence of childhood asthma in recentdecades[1].Earlier studies have shown that air pa...Asthma is a common chronic inflammatory disorder that is more prevalent in children than in adults.China has seen an increasing prevalence of childhood asthma in recentdecades[1].Earlier studies have shown that air particulate matter (PM),particularly fine particulate matter(PM2.5)[2],is an important factor triggering childhood asthma. Since nationalPM2.5data were nota vailabl euntil 2013,展开更多
Two elastoplastic constitutive models based on the unified strength the- ory （UST） are established and implemented in an explicit finite difference code, fast Lagrangian analysis of continua （FLAC/FLAC3D）, which i...Two elastoplastic constitutive models based on the unified strength the- ory （UST） are established and implemented in an explicit finite difference code, fast Lagrangian analysis of continua （FLAC/FLAC3D）, which includes an associated/non- associated flow rule, strain-hardening/softening, and solutions of singularities. Those two constitutive models are appropriate for metallic and strength-different （SD） materials, respectively. Two verification examples are used to compare the computation results and test data using the two-dimensional finite difference code FLAC and the finite element code ANSYS, and the two constitutive models proposed in this paper are verified. Two application examples, the large deformation of a prismatic bar and the strain-softening be- havior of soft rock under a complex stress state, are analyzed using the three-dimensional code FLAC3D. The two new elastoplastic constitutive models proposed in this paper can be used in bearing capacity evaluation or stability analysis of structures built of metallic or SD materials. The effect of the intermediate principal stress on metallic or SD mate- rial structures under complex stress states, including large deformation, three-dimensional and non-association problems, can be analyzed easily using the two constitutive models proposed in this paper.展开更多
Osteoporosis, characterized by loss of bone mass and microarchitectural deterioration of bone tissue, results in enhanced bone fragility and increases risk of fractureIll. In China, the incidence of primary osteoporos...Osteoporosis, characterized by loss of bone mass and microarchitectural deterioration of bone tissue, results in enhanced bone fragility and increases risk of fractureIll. In China, the incidence of primary osteoporosis is as high as 50%-70% in 60-69 years old females and approximately 30% in 60-69 years old males[21, which is closely related with the low intake of calcium. According to the nationwide nutrition and health survey in 2002 in China, the average daily calcium intake of Chinese residents is 391 mg, accounting for 41% of the recommended calcium intake.展开更多
Time fractional diffusion equation is usually used to describe the problems involving non-Markovian random walks. This kind of equation is obtained from the standard diffusion equation by replacing the first-order tim...Time fractional diffusion equation is usually used to describe the problems involving non-Markovian random walks. This kind of equation is obtained from the standard diffusion equation by replacing the first-order time derivative with a fractional derivative of order α∈(0, 1). In this paper, an implicit finite difference scheme for solving the time fractional diffusion equation with source term is presented and analyzed, where the fractional derivative is described in the Caputo sense. Stability and convergence of this scheme are rigorously established by a Fourier analysis. And using numerical experiments illustrates the accuracy and effectiveness of the scheme mentioned in this paper.展开更多
In this paper, three implicit finite difference methods are developed to solve one dimensional time fractional advection-diffusion equation. The fractional derivative is treated by applying right shifted Grünwald...In this paper, three implicit finite difference methods are developed to solve one dimensional time fractional advection-diffusion equation. The fractional derivative is treated by applying right shifted Grünwald-Letnikov formula of order α ∈(0, 1). We investigate the stability analysis by using von Neumann method with mathematical induction and prove that these three proposed methods are unconditionally stable. Numerical results are presented to demonstrate the effectiveness of the schemes mentioned in this paper.展开更多
In order to solve the problem of large temperature difference between the center and ends of the metallic rod in the purification process of solid-state electrotransport(SSE),three types of electrode connections of ta...In order to solve the problem of large temperature difference between the center and ends of the metallic rod in the purification process of solid-state electrotransport(SSE),three types of electrode connections of tantalum and the corresponding rods of metallic lanthanum were designed,the temperature distributions of three kinds of rod were measured,and the influence of temperature difference on the purification effect of solid-state electrotransport was investigated.The results indicate that the maximum temperature difference of the rod will be significantly reduced through decreasing the cross section of electrode connection to make its unit length resistance close to that of rod,or increasing the unit length resistance of the section at both ends of the rod.When these two measures are adopted at the same time,the effect of decreasing rod temperature difference is the best in the present study,and the maximum temperature difference of the rod can be reduced to 29℃when the maximum temperature of the rod is 820℃.The migration velocity of the impurities at rod ends can be obviously improved after the rod temperature difference is reduced,which enables the purification effect and efficiency of solid-state electrotransport to be greatly raised;it is also found that the major impurities iron in metallic lanthanum migrates more easily than oxygen and carbon during the purification of metal lanthanum with solid-state electrotransport.展开更多
Straw checkerboard sand barriers with a porous structure that consists of a pervious upper portion and a dense lower portion are widely used to achieve great sand control effect.Considering this,and resolving the seri...Straw checkerboard sand barriers with a porous structure that consists of a pervious upper portion and a dense lower portion are widely used to achieve great sand control effect.Considering this,and resolving the serious earth surface undercutting problem after HDPE sandbreak net checkboard barriers setting,the authors used HDPE(high-density polyethylene)materials to prepare new sandbreak materials with a similar porous structure.Through wind tunnel simulations and field sand control monitoring,we compared the sand control effect of three HDPE sandbreak nets with different porosity structure.Compared to the sandbreak net with uniform porosity structure,the three types of HDPE sandbreak nets with different porosity structure had poorer effect on reducing sand transport rates,but had longer effective protection distance before sandbreak nets at low wind velocity conditions(<12 m/s),longer effective protection distance at high wind velocity(>14 m/s)and longer effective protection distance between sandbreak nets at all experimental wind velocity conditions.Wind and sand control effect characteristics of HDPE sandbreak nets with different porosity structure provide an ideal material on semiburied checkerboard sand barriers for sand stabilization.By contrast,uniform-type sandbreak nets are used as materials on high upright sand fences for sand blocking.These HDPE sandbreak nets can be used to replace traditional sandbreak materials and have a very high potential for widespread and popular application in aeolian sand disaster control.展开更多
A pH dependent reduction in growth, Pigment, ATP content, O,' evolution, carbonfixation, Photosynthetic electron transport system, nutrient uptake (NO,' and NH4+),nitrate reductase, and ATPase activities and i...A pH dependent reduction in growth, Pigment, ATP content, O,' evolution, carbonfixation, Photosynthetic electron transport system, nutrient uptake (NO,' and NH4+),nitrate reductase, and ATPase activities and increase in K+ emux of Chlorella vulgaris wasnoticed following supplementation of Cu and Ni to the culture medium. PS II was foundto be more sensitive to both pH and metals than PS I. Though, nitrate reductase (NR) wasmore sensitive to both PH and metals, the ATPase was however, more sensitive t0 metalsbut less sensitive to acidic pH. Acid PH was found to dst the nutrient (NO,' and NH4+)uptake and nitrate reductase in a non-competitive manner. The inhibition Pnduced by thetest metals alone was of noncompetitive type for NO3' uptake, nitrate reductase andATPase and competitive for NH'+ uptake. Acidity not only inhibited the metabolicvariables directly but also through facilitated uptake of metals and increased membranepermeability. A very low sensitivity of ATPase to acidic pH seems to be resgnsible forthe survival of algae in acid environment.展开更多
基金supported financially by the National Key Research and Development Program of China (Nos. 2017YFB0702001 and 2016YFB0301105)the National Natural Science Foundation of China Projects (Nos. 51901047,51871211 and51701129)+5 种基金the Doctor Startup Fund of Natural Science Foundation Program of Liaoning Province (No. 2019-BS-200)the Strategic New Industry Development Special Foundation of Shenzhen (No. JCYJ20170306141749970)the Funds of International Joint Laboratory for Light Alloys, the Liaoning Bai Qian Wan Talents Programthe Domain Foundation of Equipment Advance Research of 13th Five-year Plan (No. 61409220118)the Innovation Fund of Institute of Metal Research (IMR), Chinese Academy of Sciences (CAS)the National Basic Research Program of China (No. 2013CB632205)。
文摘The so-called 'negative difference effect'(NDE) was often defined by the increasing rate of hydrogen evolution from magnesium(Mg) surface under anodic polarization.In this work,a series of electrochemical tests and microstructure observations were performed to provide an evidence that the NDE of Mg-Li alloys can be retarded by increasing lithium content.Potentiostatic,galvanostatic and potentiodynamic polarization experiments using Mg-xLi(x=4,7.5 and 14 wt%) alloys electrodes indicated that Mg-4 Li alloy maintained the enhancing NDE prior to anodic dissolution as that of conventional Mg alloys.However,the emergence of β-Li phase weakened the NDE of duplex Mg-7.5 Li alloy at a low anodic current density,but it was still enhanced apparently after a high applied anodic value(more than 2 mA/cm^2).The surface observations,including the plane and cross-sectional morphologies,confirmed that the cracked surface film derived from the anodic dissolution resulted in the catalytic activity of NDE for Mg-4 Li and Mg-7.5 Li alloys.Furthermore,the NDE of Mg-14 Li alloy was suppressed obviously after a prior applied anodic polarization,which was attributed to the persistent and integrated surface film which endured a higher level of applied anodic potential and current.
基金supported by the Special Earthquake Research Project Granted by the China Earthquake Administration(201308009)
文摘In comparison with the ITRF2000 model, the ITRF2005 model represents a significant improvement in solution generation, datum definition and realization. However, these improvements cause a frame difference between the ITRF2000 and ITRF2005 models, which may impact GNSS data processing. To quantify this im- pact, the differences of the GNSS results obtained using the two models, including station coordinates, base- line length and horizontal velocity field, were analyzed. After transformation, the differences in position were at the millimeter level, and the differences in baseline length were less than 1 ram. The differences in the hori- zontal velocity fields decreased with as the study area was reduced. For a large region, the differences in these value were less than 1 mm/a, with a systematic difference of approximately 2 degrees in direction, while for a medium-sized region, the differences in value and direction were not significant.
基金Supported by project of China Geological Survey(No.12120113098400)
文摘There is usually source effect in the field work of controlled-source audio-frequency magnetotelluric method.Source effect is a thorny problem during field working,data processing and interpretation.Therefore,it is very important for the results of field prospecting to model source effect and summarize its influence rules.Based on the previous research,the authors use 3D finite difference method to simulate the electromagnetic field and set different anomaly situation to study the source effect in near-field measurement,then conclude the influence rules of source effect.Simulations provide the reference for the actual field work and data processing to correct the influence of source effect,so the information of the underground will be more approaching to the real.
文摘The English vocabulary study is a very complicated process,affected by lots of factors.This article will analyze several important individual differences among learners,such as,learning style,gender and learning strategy,exploring the most effective ways to expand English vocabulary.
文摘In the present paper two contents are enclosed .First ,the Fourier analysis approach of the dispersion relation and group velocity effect of finite difference schemes is discussed.the defects of the approach is pointed out and the correction is made;Second,a new systematic analysis method -remaider -effect analysis (abbr.REAM)is proposed by means of the modified partial differential equations (abbr MPDE)of finite difference schemes.The analysis is based on the synthetical study of the rational dispersion-and dissipation relations of finite difference schemes.And the method clearly possesses constructivity
文摘Framework definitions of earlier informally used notions of effect and phenomenon are proposed, examples of their role in developing mathematics are given. Phenomena of singular cycle and deepening boundary layer in the theory of singularly perturbed differential equations and ancient popular synergetic process described by system of random difference equations are presented.
基金the National Natural Science Foundation of China, No. 30270445
文摘BACKGROUND： Prenatal stress has been shown to inhibit cell proliferation in the dentate gyrus and hippocampus, reduce hippocampal volume, and cause neuronal loss and oxidative damage in the hippocampus of offspring rats, but the sexual difference of the effects on offsprings is seldom referred to. OBJECTIVE： To observe the effect of prenatal stress to adult pregnant rats on expression of extracellular signal-regulated kinases （ERK） in hippocampus of the offspring rats of different genders. DESIGN ： A randomized and control animal experiment.SETTING： Department of Physiology and Pathophysiology, School of Medicine, Xi＇an Jiaotong University. MATERIALS ： The experiments were carried out in the Key Laboratory of Environment and Gene Related Diseases （Xi＇an Jiaotong University）, Ministry of Education between October 2005 and March 2006. Fifteen female and five male adult Sprague-Dawley rats were adopted. Female rats weighing 230-250 g and male rats weighing 280-350 g were used. METHODS： The virgin female rats were placed overnight with adult male rats （3：1） for mating. A total of twelve pregnant rats were randomly assigned to prenatal stress group （PNS group, n=6） and control group （n=6）. The pregnant rats of the PNS group were exposed to restraint stress on days 14-20 of pregnancy three times a day, 45 minutes for each time . The restraint device was a transparent plastic tube （6.8 cm in diameter） with air holes for breathing and closed end. The length could be adjusted to accommodate the size of the animals. To prevent habituation of animals to the daily procedure, restraint periods were randomly shifted within certain time periods （8：00-11：00, 11：00-14：00, and 16：00-19：00）. After birth, offsprings of all groups were culled to 8-10 litters in each group and housed in the same animal room, and kept together with their biologic mothers. The pregnant rats of the control group were left undisturbed. On day 21, after all the offspring were weaned, male and female pups were separated and housed four in each cage respectively until test at 30 days of age. At the end of postnatal day 30, one male and female offspring rats from the same dam were selected with a random choice and a total of 24 animals from 12 different dams were used. The experimental rats were sacrificed by decapitation under anesthesia. Bilateral hippocampal tissues were isolated and homogenized in cold condition. Alkaline carbonate buffer （BCA） method was used to detect the concentration of extracellular signal-regulated kinases （ERK）, then mixed with loading buffer, the constant voltage was 100 V. Finally, BCIP/NBT staining and electrDphoresis were performed, the absorbance （A） value for the bands was detected with the Bandscan analytical software, and the expression of ERK in hippocampus of offspring rats of different genders in each group was quantitatively analyzed. MAIN OUTCOME MEASURES： The level of ERK expression in hippocampus of offspring rats of different genders in each group was observed.RESULTS： All the 24 offspring rats were involved in the analysis of results. ① The staining results of ERP activity in the extract of brain tissue detected with Western blotting technique and specific antibody analysis showed that the ERP in hippocampus of offspring rats had two subtypes of ERK-1 and ERK-2, and the latter was the main type.② Standardized by the average A value in the control group, the quantitative data of the general A value of total ERK showed that the expression of ERK-2 in hippocampus of female offspring rats was obviously higher in the PNS group than in the control group （A value： 126±6.76,100±4.89,P〈 0.01）. ③The expression of ERK-2 had no obvious difference between the female and male offspring rats in the control group.④ The expression of ERK-2 in hippocampus of male offspring rats was a little higher in the PNS group than in the control group （A value： 104±6.27,102±5.48,P 〉 0.05）. CONCLUSION ： PNS significantly affects the increase of ERK expression in hippocampus of female offspring rats, but has no obvious influence on that of male ones.
文摘Objective: to explore the best surgical treatment of appendicitis in clinical treatment. Methods: appendicitis patients treated with surgery in our hospital from March 2019 to February 2021 were included in the study. According to the different operations selected, 63 cases were divided into the laparoscopic operation group and 61 cases were divided into the laparotomy operation group. The clinical effects of patients treated with different operations were compared. Results: (1) there were significant differences in the amount of bleeding, treatment time, exhaust time, ambulation time, and hospitalization time between the two groups (P<0.05, t=2.055, 2.197, 2.734, 1.935, 2.393). (2) Analysis of postoperative complications in two groups. The total incidence of complications between groups was 3.17% (2 cases) and 22.95% (14 cases), respectively, and the difference was significant (P < 0.05, χ2 =3.771). Conclusion: laparoscopic surgery is a good choice for appendicitis patients with less complication.
文摘Objective To investigate the effect of gender differences in distal femoral geometry on the clinical outcomes of total knee arthroplasty (TKA).Methods From March 2003 to October 2006,213 cases with 294 osteoarthritic knees who
文摘Objective To observe postoperative effect of electroacupuncture（EA） of different frequencies in acupuncture anesthesia combined with drugs on patients undergoing thyroid surgery.Methods One hundred and twenty patients undergoing thyroid surgery were randomly divided into a 2Hz electroacupuncture anesthesia group（group A）,a 100 Hz electroacupuncture anesthesia group（group B）,a 2Hz/100 Hz electroacupuncture anesthesia group（group C） and a cervical plexus block group（group D） in accordance with the random number table method,with 30 patients in each group.In group A,group B and group C,electroacupuncture was applied at bilateral Futu（扶突 LI 18）,Hegu（合谷 LI 4） and Neiguan（内关 PC 6） at frequencies of 2 Hz,100 Hz and 2 Hz/100 Hz respectively for 30 min.The needles were retained till the end of the surgery.Dolantin and atropine were intramuscularly injected In group D,bilateral cervical plexus block was produced with a mixture of1%lidocaine and 0.375%bupivicaine.Before surgery,pain threshold and threshold of pain tolerance were determined;during surgery,the duration of surgery was recorded;and after surgery,QOLS（Quality Of Life Score） and PHS（Prince-Henry Score） were assessed.Results PHS in group A,group B and group C were lower than that in group D,respectively（0.20±0.41,0.17±0.38,0.10±0.31 vs 0.40±0.50,P〈0.01）,and PHS in group C was lower than those in group A and group B,respectively（both P〈0.01）.QOLS in group A,group B and group C were higher than that in group D,respectively（9.97±1.07,9.97±2.27,10.40±1.45 vs 9.73±1.41,P〈0.05,P〈0.01）,and QOLS in group C was higher than those in group A and group B,respectively（both P〈0.05）.Conclusion Acupuncture anesthesia combined with drugs has better postoperative effect than drug anesthesia.Electroacupuncture of different frequencies can significantly improve general quality of life of patients,so patients recover well after thyroid surgery.As patients in group C suffered from the slightest pain with the highest quality of life,they recovered best within the shortest time.Electroacupuncture at frequency of 2 Hz/100 Hz can better play postoperative analgesic effect.
基金supported by National Natural Science Foundation of China(71003041)the Fundamental Research Funds of the Central Universities(2662015PY198)
文摘Rural-urban land conversion is a universal phenomenon in the rapid process of economic development and urban growth.The welfare of farmers who lost their farmland attracted a widespread concern within the society and academia.However,further research about differentiated policies according to the characteristics of different farmer groups is still need to be conducted.This article divides the land-lost farmers into three age groups:younger than 45,45-65,and more than 65.It proposes a welfare index system including eight functional areas based on different age groups of affected farmers,taking four districts of Wuhan City as case study area.Fuzzy mathematics method is used to derive the aggregated welfare effect index.Our analysis show that the overall welfare levels of land-lost farmers of all age groups declined,but with a varying degree,with the level of welfare in those farmers who are 45-65 years old,younger than 45 years old,and older than 65 years old decreased by 18.7%,16.6%,and 12.7%,respectively.The direction and degree of effects on the functional activity index varies among different groups.Economic conditions,living environment,health,and social participation of all age groups decrease while social security and housing conditions increase.On the other hand,development opportunities,social communication,and leisure have different changing directions in different age stages.These results call for differentiated and tailor-made compensation policies for land-lost farmers,towards improving the welfare levels of all farmers and reduce the disparity among them.
基金supported by the Development Foundation of Shanghai Meteorological and Health Key Laboratory [QXJK201606]the Investigation of Science&Technology Basic Resources Program of China [2017FY101206]the General Program Foundation of Hebei Meteorological Bureau [17KY10]
文摘Asthma is a common chronic inflammatory disorder that is more prevalent in children than in adults.China has seen an increasing prevalence of childhood asthma in recentdecades[1].Earlier studies have shown that air particulate matter (PM),particularly fine particulate matter(PM2.5)[2],is an important factor triggering childhood asthma. Since nationalPM2.5data were nota vailabl euntil 2013,
基金Project supported by the National Natural Science Foundation of China (No. 41172276)the Central Financial Funds for the Development of Characteristic Key Disciplines in Local Universities(Nos. 106-00X101 and 106-5X1205)
文摘Two elastoplastic constitutive models based on the unified strength the- ory （UST） are established and implemented in an explicit finite difference code, fast Lagrangian analysis of continua （FLAC/FLAC3D）, which includes an associated/non- associated flow rule, strain-hardening/softening, and solutions of singularities. Those two constitutive models are appropriate for metallic and strength-different （SD） materials, respectively. Two verification examples are used to compare the computation results and test data using the two-dimensional finite difference code FLAC and the finite element code ANSYS, and the two constitutive models proposed in this paper are verified. Two application examples, the large deformation of a prismatic bar and the strain-softening be- havior of soft rock under a complex stress state, are analyzed using the three-dimensional code FLAC3D. The two new elastoplastic constitutive models proposed in this paper can be used in bearing capacity evaluation or stability analysis of structures built of metallic or SD materials. The effect of the intermediate principal stress on metallic or SD mate- rial structures under complex stress states, including large deformation, three-dimensional and non-association problems, can be analyzed easily using the two constitutive models proposed in this paper.
文摘Osteoporosis, characterized by loss of bone mass and microarchitectural deterioration of bone tissue, results in enhanced bone fragility and increases risk of fractureIll. In China, the incidence of primary osteoporosis is as high as 50%-70% in 60-69 years old females and approximately 30% in 60-69 years old males[21, which is closely related with the low intake of calcium. According to the nationwide nutrition and health survey in 2002 in China, the average daily calcium intake of Chinese residents is 391 mg, accounting for 41% of the recommended calcium intake.
基金Supported by the Discipline Construction and Teaching Research Fund of LUTcte(20140089)
文摘Time fractional diffusion equation is usually used to describe the problems involving non-Markovian random walks. This kind of equation is obtained from the standard diffusion equation by replacing the first-order time derivative with a fractional derivative of order α∈(0, 1). In this paper, an implicit finite difference scheme for solving the time fractional diffusion equation with source term is presented and analyzed, where the fractional derivative is described in the Caputo sense. Stability and convergence of this scheme are rigorously established by a Fourier analysis. And using numerical experiments illustrates the accuracy and effectiveness of the scheme mentioned in this paper.
文摘In this paper, three implicit finite difference methods are developed to solve one dimensional time fractional advection-diffusion equation. The fractional derivative is treated by applying right shifted Grünwald-Letnikov formula of order α ∈(0, 1). We investigate the stability analysis by using von Neumann method with mathematical induction and prove that these three proposed methods are unconditionally stable. Numerical results are presented to demonstrate the effectiveness of the schemes mentioned in this paper.
基金financially supported by the National Basic Research Program of China(No.2012CBA01207)the National High Technology Research and Development Program of China(No.2011AA03A409)。
文摘In order to solve the problem of large temperature difference between the center and ends of the metallic rod in the purification process of solid-state electrotransport(SSE),three types of electrode connections of tantalum and the corresponding rods of metallic lanthanum were designed,the temperature distributions of three kinds of rod were measured,and the influence of temperature difference on the purification effect of solid-state electrotransport was investigated.The results indicate that the maximum temperature difference of the rod will be significantly reduced through decreasing the cross section of electrode connection to make its unit length resistance close to that of rod,or increasing the unit length resistance of the section at both ends of the rod.When these two measures are adopted at the same time,the effect of decreasing rod temperature difference is the best in the present study,and the maximum temperature difference of the rod can be reduced to 29℃when the maximum temperature of the rod is 820℃.The migration velocity of the impurities at rod ends can be obviously improved after the rod temperature difference is reduced,which enables the purification effect and efficiency of solid-state electrotransport to be greatly raised;it is also found that the major impurities iron in metallic lanthanum migrates more easily than oxygen and carbon during the purification of metal lanthanum with solid-state electrotransport.
基金fund by Strategic Priority Research Program of the Chinese Academy of Sciences(XD23060201)the National Natural Science Foundation of China(41730644,42171016,)。
文摘Straw checkerboard sand barriers with a porous structure that consists of a pervious upper portion and a dense lower portion are widely used to achieve great sand control effect.Considering this,and resolving the serious earth surface undercutting problem after HDPE sandbreak net checkboard barriers setting,the authors used HDPE(high-density polyethylene)materials to prepare new sandbreak materials with a similar porous structure.Through wind tunnel simulations and field sand control monitoring,we compared the sand control effect of three HDPE sandbreak nets with different porosity structure.Compared to the sandbreak net with uniform porosity structure,the three types of HDPE sandbreak nets with different porosity structure had poorer effect on reducing sand transport rates,but had longer effective protection distance before sandbreak nets at low wind velocity conditions(<12 m/s),longer effective protection distance at high wind velocity(>14 m/s)and longer effective protection distance between sandbreak nets at all experimental wind velocity conditions.Wind and sand control effect characteristics of HDPE sandbreak nets with different porosity structure provide an ideal material on semiburied checkerboard sand barriers for sand stabilization.By contrast,uniform-type sandbreak nets are used as materials on high upright sand fences for sand blocking.These HDPE sandbreak nets can be used to replace traditional sandbreak materials and have a very high potential for widespread and popular application in aeolian sand disaster control.
文摘A pH dependent reduction in growth, Pigment, ATP content, O,' evolution, carbonfixation, Photosynthetic electron transport system, nutrient uptake (NO,' and NH4+),nitrate reductase, and ATPase activities and increase in K+ emux of Chlorella vulgaris wasnoticed following supplementation of Cu and Ni to the culture medium. PS II was foundto be more sensitive to both pH and metals than PS I. Though, nitrate reductase (NR) wasmore sensitive to both PH and metals, the ATPase was however, more sensitive t0 metalsbut less sensitive to acidic pH. Acid PH was found to dst the nutrient (NO,' and NH4+)uptake and nitrate reductase in a non-competitive manner. The inhibition Pnduced by thetest metals alone was of noncompetitive type for NO3' uptake, nitrate reductase andATPase and competitive for NH'+ uptake. Acidity not only inhibited the metabolicvariables directly but also through facilitated uptake of metals and increased membranepermeability. A very low sensitivity of ATPase to acidic pH seems to be resgnsible forthe survival of algae in acid environment.
