Background： With the progress ofperinatal medicine and neonatal technology, more and more extremely low birth weight （ELBW） survived all over the world. This study was designed to investigate the short-term ontcome...Background： With the progress ofperinatal medicine and neonatal technology, more and more extremely low birth weight （ELBW） survived all over the world. This study was designed to investigate the short-term ontcomes of ELBW infants during their Neonatal Intensive Care Unit （NICU） stay in the mainland of China. Methods： All infants admitted to 26 NICUs with a birth weight （BW） 〈1000 g were included between January 1,2011 and December 31,2011. All the data were collected retrospectively from clinical records by a prospectively designed questionnaire. The data collected from each NICU transmitted to the main institution where the results were aggregated and analyzed. Categorical variables were performed with Pearson Chi-square test. Binary Logistic regression analysis was used to detect risk factors. Results： A total of 258 ELBW infants were admitted to 26 NICUs, of whom the mean gestational age （GA） was 28.1 ± 2.2 weeks, and the mean BW was 868 ± 97 g. The overall survival rate at discharge was 50.0%. Despite aggressive treatment 60 infants （23.3%） died and another 69 infants （26.7%） died after medical care withdrawal. Furthermore, the survival rate was significantly higher in coastal areas than inland areas （53.6% vs. 35.3%, P = 0.019）. BW 〈750 g and GA 〈28 weeks were the largest risk factors, and being small for gestational age was a protective factor related to mortality. Respiratory distress syndrome was the most common complication. The incidence of patent ductus arteriosus, intraventricular hemorrhage, periventricular leukomalacia, bronchopulmonary dysplasia, retinopathy of prematurity was 26.2%, 33.7%, 6.7%, 48.1%, and 41.4%, respectively. Ventilator associated pneumonia was the most common hospital acquired infection during hospitalization. Conclusions： Our study was the first survey that revealed the present status of ELBW infants in the mainland of China. The mortality and morbidity of ELBW infants remained high as compared to other developed countries.展开更多
Sublethal effects of chlorantraniliprole to Helicoverpa armigera （Hiibner） larvae were evaluated through exposure of third instar larvae to the insecticide incorporated into an artificial diet. When larvae were fed ...Sublethal effects of chlorantraniliprole to Helicoverpa armigera （Hiibner） larvae were evaluated through exposure of third instar larvae to the insecticide incorporated into an artificial diet. When larvae were fed on the insecticide-containing diet for 7 d, the LC10, LC20, LC40, and LC50values were 3.790, 7.977, 21.577, and 33.121 μg active ingredient L^-1, respectively. Chlorantraniliprole at sublethal concentrations significantly reduced the larval body mass, emergence ratio, adult longevity and egg hatching rate in both the parental and offspring generations. The pupation and copulation rate in the parental generation and the pupal mass in the offspring also strongly decreased. Reproduction was seriously disturbed in both the parental and offspring groups even when only one of the partners was exposed to chlorantraniliprole at larval stages. However, at the lowest concentration of exposure （LC^0）, offspring fecundity was strongly reduced only when both partners were exposed. The net reproductive rate （R0）, intrinsic rate of increase （rm）, and gross reproduction rate （GRR） at LC20, LC40 concentrations were significantly lower than that of the control. Post-exposure effects also included an extended larval developmental time and increased male proportion in both generations. The doubling time （Dt） at LC20, LC40 concentrations as well as gross reproduction rate （GRR） at LC10 concentration were also significantly increased. Chlorantraniliprole might have significant effects on H. armigera population dynamics even at sublethal concentrations on both parental and offspring generations.展开更多
Estrogen plays an important role in regulating Sertoli cell number in the testis. The objective of the study was to identify whether 17β-estradiol affected the proliferation of cultured, immature boar Sertoli cells v...Estrogen plays an important role in regulating Sertoli cell number in the testis. The objective of the study was to identify whether 17β-estradiol affected the proliferation of cultured, immature boar Sertoli cells via the estrogen receptor β （ERβ） and the cAMP-extracellular signal-regulated kinase （ERK1/2） pathway. Low levels （10-10-10-8 mol L-1） of 17β-estradiol increased cell number, but high levels （10-7-10-6 mol L-1） decreased it （P〈0.05）. Sertoli cell number began to recover for an additional 24 h in the medium without 17β-estradiol （10-6 mol L-l） （P〉0.05）. The effects of 17β-estradiol （10-9 mol L-1） peaked at the first 24 h （P〈0.05）. 17β-estradiol activated ERK1/2 from 5 min to 24 h, but the activiy of ERK1/2 began to decrease after 4 h. Both PD98059 and U0126, two ERK inhibitors, blocked cell division （P〈0.05）. 17β-estradiol （10-10-10-6 mol L-1） dose-dependently increased cAMP production （P 〈 0.05）, and both 17β-estradiol （10-9 mol L-1） and forskolin, which increases cAMP levels, induced cell proliferation and activated ERK1/2 （P〈 0.05）. Rp-cAMP, an antagonist of cAMP, blocked this 17β-estradiol activity （P〈 0.05）. Two estrogen receptor antagonists, ICI 182780 and ERβ antagonist （ERβAnt）, reduced Sertoli cell number, cAMP production and ERK1/2 activation （P〈 0.05）, but ERaAnt did not （P〉 0.05）. Therefore, 17β- estradiol mainly promotes pig Sertoli cell proliferation via ERβ to induce cAMP production and ERK activation to promote cell proliferation.展开更多
Amino acids are the building blocks of protein synthesis.They are structural elements and energy sources of cells necessary for normal cell growth,differentiation and function.Amino acid metabolism disorders have been...Amino acids are the building blocks of protein synthesis.They are structural elements and energy sources of cells necessary for normal cell growth,differentiation and function.Amino acid metabolism disorders have been linked with a number of pathological conditions,including metabolic diseases,cardiovascular diseases,immune diseases,and cancer.In the case of tumors,alterations in amino acid metabolism can be used not only as clinical indicators of cancer progression but also as therapeutic strategies.展开更多
High pressure and water-bearing caverns ahead of a karst tunnel face tend to cause geological disasters, such as water and mud bursts. So, the determination of safe thickness of the reserved rock plug is a key technic...High pressure and water-bearing caverns ahead of a karst tunnel face tend to cause geological disasters, such as water and mud bursts. So, the determination of safe thickness of the reserved rock plug is a key technical problem to be solved for karst tunnel construction. Based on the Hoek-Brown nonlinear failure criterion, the minimum safe thickness of rock plug was investigated in the light of the limit analysis theory. On the basis of the proposed failure mode, the expression of the minimum thickness for rock plug was obtained by means of upper bound theorem in combination with variational principle. The calculation results show the influence of each parameter on safe thickness and reveal the damage range of rock plug. The proposed method is verified by comparing the results with those of the drain cavern of Maluqing Tunnel. The research shows that with the increase of compressive strength and tensile strength as well as constant A of Hoek-Brown criterion, the safe thickness decreases, whereas with the increase of cavern pressure, tunnel diameter, and constant B from Hoek-Brown criterion, the safe thickness increases. Besides, the tensile strength, or constants A and B affect the shear failure angle of rock plug structure, but other parameters do not. In conclusion, the proposed method can predict the minimum safe thickness of rock plug, and is useful for water burst study and prevention measures of tunnels constructed in high-risk karst regions.展开更多
Background Gastric cancer ranks high among the most common causes of cancer-related death worldwide. This study was designed to explore key genes involved in the progression of normal gastric epithelial cells to moder...Background Gastric cancer ranks high among the most common causes of cancer-related death worldwide. This study was designed to explore key genes involved in the progression of normal gastric epithelial cells to moderate gastric epithelial dysplasia （mGED） and to gastric cancer. Methods Twelve pairs of mGED tissues, gastric cancer tissues, and normal gastric tissues were collected by gastroscopy. Total RNA was then extracted and purified. After the addition of fluorescent tags, hybridization was carried out on a Gene chip microarray slide. Significance analysis of microarrays was performed to determine significant differences in gene expression between the different tissue types. Results Microarray data analysis revealed totally 34 genes that were expressed differently： 18 highly expressed （fold change 〉2; P 〈0.01） and 16 down-regulated （fold change 〉2; P 〈0.01）. Of the 34 genes, 24 belonged to several different functional categories such as structural molecule activity, extracellular regions, structural formation, cell death, biological adhesion, developmental processes, locomotion, and biological regulation that were associated with cancer. The remaining 10 genes were not involved in cancer research. Of these genes, the expression levels of Matrix metalloproteinase-12 （MMP12）, Caspase-associated recruitment domain 14 （CARD14）, and Chitinase 3-like 1 （CHI3L1） were confirmed by semi-quantitative RT-PCR. A two-way clustering algorithm divided the 36 samples into three categories and the overall correct classification efficiency was 80.6% （29/36）. Almost all of these genes （31/34） showed constant changes in the process of normal gastric epithelial cells to mGED to gastric cancer. Conclusions The results of this study provided global gene expression profiles during the development and progression from normal gastric epithelial cells to mGED to gastric cancer. These data may provide new insights into the molecular pathology of gastric cancer which may be useful for the detect展开更多
Indica-japonica hybrid rice(Oryza sativa L.) cultivars showed high yield potential and poor tasting quality when compared with common japonica rice cultivars. Large panicle is a prominent factor of high yield for indi...Indica-japonica hybrid rice(Oryza sativa L.) cultivars showed high yield potential and poor tasting quality when compared with common japonica rice cultivars. Large panicle is a prominent factor of high yield for indica-japonica hybrid rice cultivars, and the panicle weight varies greatly among different indica-japonica hybrid rice cultivars. It is important to research on yield and grain quality of different panicle weight indica-japonica hybrid rice cultivars. In this study, two different panicle types indica-japonica hybrid cultivars were used to research on the relation of yield and grain quality. The yields of two heavy panicle weights indica-japonica hybrid cultivars were significantly higher than that of two medium panicle weight rice cultivars. The cooking and eating quality and starch properties of different panicle type cultivars were evaluated. Yongyou 6715(medium panicle) and Yongyou 1852(heavy panicle) got the relatively higher cooking and eating quality. Rice cultivars with medium panicle weight had more large starch granules and higher relative crystallinity than cultivars with heavy panicle weight. Transition temperature and retrogradation enthalpy(ΔHret) of medium panicle type cultivars were significantly higher than that of heavy panicle type cultivars. There was no significant difference in amylose content among different panicle type cultivars. Protein content of heavy panicle type cultivar was higher than that of medium panicle type cultivar, and protein content is the main factor affect cooking and eating quality in this study. The cultivar Yongyou 6715 got the highest taste value with the lowest protein content. Thus, it is suggested that the emphasis on improving rice cooking and eating quality of indica-japonica hybrid rice cultivars is how to reduce the protein content in rice grain. According to the results of this study, medium panicle type with high grain weight is the desired panicle type for high quality indica-japonica hybrid rice breeding.展开更多
Acetamiprid has a wide range of influence on physiological functions in mammals.The objective of this study was to examine the effect of acetamiprid on the reproductive function of male mice,and to study the role of o...Acetamiprid has a wide range of influence on physiological functions in mammals.The objective of this study was to examine the effect of acetamiprid on the reproductive function of male mice,and to study the role of oxidative stress in acetamiprid-induced damage to the testes.Fifty adult Kunmin male mice （25-30 g） were divided into five groups （n=10 per group）,i.e.,control,blank,acetamiprid alone,acetamiprid and vitamin E,and vitamin E alone.All groups were treated for 35 d.The results showed that acetamiprid significantly decreased the body weight and the weight of testosterone-responsive organs,such as the testis,epididymis,seminal vesicle,and prostate.Furthermore,acetamiprid also significantly reduced the serum testosterone concentration,and decreased sperm count,viability,motility,and the intactness of the acrosome （P〈0.05 for each parameter）.The mice treated with acetamiprid had damaged seminiferous tubules and Leydig cells based on the histological structure of testes;there was degeneration of the mitochondria and endoplasmic reticulum of Leydig cells.These deleterious effects of acetamiprid may be mediated by increasing oxidative stress,as acetamiprid increased malondialdehyde and nitric oxide in the testes,reduced the activity of catalase,glutathione peroxidase,superoxide dismutase,and activated p38.The concentration of acetamiprid in the testes was lower than that in liver,so did the concentrations of liver function tests,including aspartate transaminase （AST）,alanine transaminase （ALT） and alkaline phosphatase （ALP）,which suggest that male reproductive function may be affected through the indirect action of its metabolites.Vitamin E significantly ameliorated the effects of acetamiprid.We conclude that acetamiprid damages male reproductive function through inducing oxidative stress in the testes.展开更多
At present, radical resection remains the only effective treatment for patients with hilar cholangiocarcinoma. The surgical approach for R0 resection of hilar cholangiocarcinoma is complex and diverse, but for the bil...At present, radical resection remains the only effective treatment for patients with hilar cholangiocarcinoma. The surgical approach for R0 resection of hilar cholangiocarcinoma is complex and diverse, but for the biliary reconstruction after resection, almost all surgeons use Roux-en-Y hepaticojejunostomy. A viable alternative to Roux-en-Y reconstruction after radical resection of hilar cholangiocarcinoma has not yet been proposed. We report a case of performing duct-to-duct biliary reconstruction after radical resection of Bismuth Ⅲa hilar cholangiocarcinoma. End-to-end anastomosis between the left hepatic duct and the distal common bile duct was used for the biliary reconstruction, and a singlelayer continuous suture was performed along the bile duct using 5-0 prolene. The patient was discharged favorably without biliary fistula 2 wk later. Evidence for tumor recurrence was not found after an 18 mo follow- up. Performing bile duct end-to-end anastomosis in hilar cholangiocarcinoma can simplify the complex digestive tract reconstruction process.展开更多
A method of analyzing the stability of twin shallow tunnels was presented using both limit analysis with nonlinear failure criterion and reliability theory.In the condition of nonlinear failure criterion,the critical ...A method of analyzing the stability of twin shallow tunnels was presented using both limit analysis with nonlinear failure criterion and reliability theory.In the condition of nonlinear failure criterion,the critical clear distancesof twin shallow tunnels were obtained by analyzing the change of surrounding pressure.A reliability model was established based on limit state equation,and the failure probability was solved by virtue of Monte Carlo method.Safety factor and corresponding clear distance of different safety levels were obtained by introducing a target reliability index.The scope of clear distance for different safety levels is described,which can be used as a supplement and improvement to the design codes of tunnels.展开更多
A new horn failure mechanism was constructed for tunnel faces in the soft rock mass by means of the logarithmic spiral curve. The seismic action was incorporated into the horn failure mechanism using the pseudo-static...A new horn failure mechanism was constructed for tunnel faces in the soft rock mass by means of the logarithmic spiral curve. The seismic action was incorporated into the horn failure mechanism using the pseudo-static method. Considering the randomness of rock mass parameters and loads, a three-dimensional (3D) stochastic collapse model was established. Reliability analysis of seismic stability of tunnel faces was presented via the kinematical approach and the response surface method. The results show that, the reliability of tunnel faces is significantly affected by the supporting pressure, geological strength index, uniaxial compressive strength, rock bulk density and seismic forces. It is worth noting that, if the effect of seismic force was not considered, the stability of tunnel faces would be obviously overestimated. However, the correlation between horizontal and vertical seismic forces can be ignored under the condition of low calculation accuracy.展开更多
Background Pancreatic cancer is one of the most common tumors and has a 5-year survival for all stages of less than 5%. Most patients with pancreatic cancer are diagnosed at an advanced stage and therefore are not can...Background Pancreatic cancer is one of the most common tumors and has a 5-year survival for all stages of less than 5%. Most patients with pancreatic cancer are diagnosed at an advanced stage and therefore are not candidates for surgical resection. In recent years, investigation into alternative treatment strategies for this aggressive disease has led to advances in the field of gene therapy for pancreatic cancer. E. coil purine nucleoside phosphorylase/6-methylpurine deoxyribose （ePNP/MePdR） is a suicide gene/prodrug system where PNP enzyme cleaves nontoxic MePdR into cytotoxic membrane-permeable compounds 6-methylpurine （MeP） with high bystander activity, hTERT is expressed in cell lines and tissues for telomerase activity. In this study we examined the efficacy of ePNP under the control of hTERT promoter sequences and assessed the selective killing effects of the ePNP/prodrug MePdR system on pancreatic tumors. Methods Recombinant pET-PNP was established. The protein of E. coil PNPase was expressed and an antibody to E. coil PNPase was prepared. Transcriptional activities of hTERT promoter sequences were analyzed using a luciferase reporter gene. A recombinant phTERT-ePNP vector was constructed. The ePNP/MePdR system affects SW1990 human pancreatic cancer cell lines in vitro. Results The hTERT promoter had high transcriptional activity and conferred specificity on cancer cell lines. The antibody to E. coil PNPase was demonstrated to be specific for the ePNP protein. The MePdR treatment induced a high in vitro cytotoxicity on the sole hTERT-ePNP-producing cell lines and affected SW1990 cells in a dose-dependent manner. Conclusions The hTERT promoter control of the ePNP/MePdR system can provide a beneficial anti-tumor treatment in pancreatic cancer cell lines including a good bystander killing effect.展开更多
Background Pancreatic cancer is one of the most lethal human cancers with a very low survival rate of 5 years. Conventional cancer treatments including surgery, radiation, chemotherapy or combinations of these show li...Background Pancreatic cancer is one of the most lethal human cancers with a very low survival rate of 5 years. Conventional cancer treatments including surgery, radiation, chemotherapy or combinations of these show little effect on this disease. Several proteins have been proved critical to the development and the progression of pancreatic cancer. The aim of this study was to investigate the effect of resveratrol on apoptosis in pancreatic cancer cells. Methods Several pancreatic cancer cell lines were screened by resveratrol, and its toxicity was tested by normal pancreatic cells. Western blotting was then performed to analyze the molecular mechanism of resveratrol induced apoptosis of pancreatic cancer cell lines.展开更多
Hexagonal porous Nb2O5 was synthesized for the first time via a facile solid-state reaction.The structure and electrochemical properties have been optimized through tuning heating temperature.X-ray diffraction results...Hexagonal porous Nb2O5 was synthesized for the first time via a facile solid-state reaction.The structure and electrochemical properties have been optimized through tuning heating temperature.X-ray diffraction results indicate that pseudo hexagonal Nb2O5(TT-Nb2O5)and orthorhombic Nb2O5 have been synthesized at different temperatures.Hexagonal sheet and porous structure of Nb2O5 were characterized by scanning electron microscopy and N2-adsorption-desorption isotherms.The as-prepared TT-Nb2O5(heated at 600℃)shows the best performance with a remarkable charge capacity of 178 mA∙h/g at 0.2C,which is higher than that of T-Nb2O5.Even at 20℃,TT-Nb2O5 offers unprecedented rate capability up to 86 mA∙h/g.The high rate capacity is due to pseudocapacitive Li+intercalation mechanism of TT-Nb2O5.The reported results demonstrate that Nb2O5 with good crystal structure and high specific surface area is a powerful composite design for high-rate and safe anode materials.展开更多
AIM: To investigate whether bis (7)-tacrine, a multifunctional drug, inhibits N-methyl-D-aspartate (NMDA) -activated current in retinal ganglion cells (RGC) and provides neuroprotection against retinal cell damage. ME...AIM: To investigate whether bis (7)-tacrine, a multifunctional drug, inhibits N-methyl-D-aspartate (NMDA) -activated current in retinal ganglion cells (RGC) and provides neuroprotection against retinal cell damage. METHODS: Purified RGC cultures were obtained from retinas of 1-3 days old Sprague-Dawley (SD) rats, following a two-step immunopanning procedure. After 7 days of cultivation, the inhibition of NMDA-activated current by bis(7) -tacrine was measured by using patch-clamp recording techniques. In animal experiments, RGCs were damaged after intravitreal injection of NMDA (5 mu L, 40nmol) in adult rats. Bis (7)-tacrine(0.05, 0.1, 0.2mg/kg) or memantine(20mg/kg) was intraperitoneal administered to the rats fifteen minutes before intravitreally injection of NMDA. RGC damage was analyzed by histologic techniques, TUNEL and retrograde labeling techniques. RESULTS: Whole-cell patch-clamp recordings demonstrated that NMDA (30 mu mol/L) resulted in approximately -50 pA inward currents that were blocked by bis (7)-tacrine (1 mu mol/L). Histological examination and retrograde labeling analysis revealed that bis (7)-tacrine induced a significant neuroprotective effect against NMDA-induced cell damage 7 days after NMDA injection. TUNEL staining showed that pretreatment with bis(7)-tacrine was effective in ameliorating NMDA-induced apoptotic cell loss in the retinal ganglion cell layer 18 hours after injection. CONCLUSION: Bis (7)-tacrine possesses remarkable neuroprotective activities against retinal excitotoxicity through inhibition of NMDA receptors.展开更多
Schwannomas are rarely observed in the gastrointestinal tract.The most common symptoms of a gastric schwannoma are abdominal pain or dyspepsia,gastrointestinal bleeding,and an abdominal mass.Many gastric schwannomas a...Schwannomas are rarely observed in the gastrointestinal tract.The most common symptoms of a gastric schwannoma are abdominal pain or dyspepsia,gastrointestinal bleeding,and an abdominal mass.Many gastric schwannomas are asymptomatic and are discovered incidentally or at postmortem.The diagnosis of a schwannoma is based on immunohistochemical positivity for S-100 protein.Wepresent a case report of a rare complication of gastric schwannoma causing gastroduodenal intussusception that was successfully managed by a BillrothⅡdistal gastrectomy.In this rare case,the patient had intermittent,colicky abdominal pain,nausea,and vomiting for over 4wk accompanied by a weight loss.A diagnosis of gastric intussusception was made by computed tomography.A BillrothⅡdistal gastrectomy was then performed,and complete en bloc removal(R0 resection)was achieved.Pathology confirmed a gastric schwannoma through positive immunohistochemical staining for S-100 protein.展开更多
The Shanghai soft X-ray free-electron laser(SXFEL)user facility project started in 2016 and is expected to be open to users by 2022.It aims to deliver ultra-intense coherent femtosecond X-ray pulses to five endstation...The Shanghai soft X-ray free-electron laser(SXFEL)user facility project started in 2016 and is expected to be open to users by 2022.It aims to deliver ultra-intense coherent femtosecond X-ray pulses to five endstations covering a range of 100–620 eV for ultrafast X-ray science.Two undulator lines are designed and constructed,based on different lasing modes:self-amplified spontaneous emission and echo-enabled harmonic generation.The coherent scattering and imaging(CSI)endstation is the first of five endstations to be commissioned online.It focuses on high-resolution single-shot imaging and the study of ultrafast dynamic processes using coherent forward scattering techniques.Both the single-shot holograms and coherent diffraction patterns were recorded and reconstructed for nanoscale imaging,indicating the excellent coherence and high peak power of the SXFEL and the possibility of‘‘diffraction before destruction’’experiments at the CSI endstation.In this study,we report the first commissioning results of the CSI endstation.展开更多
The current study is to observe the effect of the locking system strengthened by biomimetic mineralized collagen putty for the treatment of senile proximal humeral osteoporotic fractures.From January 2012 to December ...The current study is to observe the effect of the locking system strengthened by biomimetic mineralized collagen putty for the treatment of senile proximal humeral osteoporotic fractures.From January 2012 to December 2015,80 cases of senile patients with osteoporotic proximal humeral fractures were randomly divided into an observation group and a control group,each group with a total of 40 cases.The control group was simply treated with locking plate.The observation group was treated with locking plate in combination with biomimetic mineralized collagen putty.The therapeutic effect thereby was observed.The excellent and satisfactory rate was 90%in observation group and was 72.5%in control group.The difference between the two groups was statistically significant(χ^(2)=5.3312,P<0.05).The fracture healing time was 11.8263.62 weeks in observation group and 19.7865.46 weeks in control group.The shoulder joint function score was 89.6368.12 in observation group and 76.9268.18 in control group.There was significant difference between the two groups(t=7.1272;12.7834,P<0.05).The complication rate was 10%in the observation group and 32.5%in the control group(χ^(2)=7.3786,P<0.05).Locking system strengthened by biomimetic mineralized collagen putty has advantages such as accelerating healing of senile proximal humeral fracture,improving the therapeutic effect,reducing the complications.As one of the optimal internal fixation method,it provides a new option for better treatment of senile osteoporotic fracture.展开更多
The pressure and deflagration to detonation transition(DDT)characteristics of acetylene and oxygen flame were studied in a detonation tube.The pressure history and the flame velocity along the tube were measured with ...The pressure and deflagration to detonation transition(DDT)characteristics of acetylene and oxygen flame were studied in a detonation tube.The pressure history and the flame velocity along the tube were measured with high frequency pressure transducers and ion probes.By analyzing the data recorded in the experiment,the detonation wave pressure,post wave pressure and DDT distance were obtained,together with the effects of the initial pressure varying from 2×10^(4)Pa to 10^(5)Pa,equivalence ration from 0.3 to 1.0,and mixture concentration from 60%to 100%.It was found that the detonation pressure was decreased respectively with the decrease of initial pressure,equivalence ratio and mixture concentration,but the DDT distance was enlarged.The DDT distance was found particularly sensitive to mixture concentration.展开更多
By making use of extended mapping method and auxiliary equation for finding new periodic wave solu tions of nonlinear evolution equations in mathematical physics, we obtain some new periodic wave solutions for general...By making use of extended mapping method and auxiliary equation for finding new periodic wave solu tions of nonlinear evolution equations in mathematical physics, we obtain some new periodic wave solutions for generalized Klein-Cordon equation and Benjamin equation, which cannot be found in previous work. This method also can be used to find new periodic wave solutions of other nonlinear evolution equations.展开更多
文摘Background： With the progress ofperinatal medicine and neonatal technology, more and more extremely low birth weight （ELBW） survived all over the world. This study was designed to investigate the short-term ontcomes of ELBW infants during their Neonatal Intensive Care Unit （NICU） stay in the mainland of China. Methods： All infants admitted to 26 NICUs with a birth weight （BW） 〈1000 g were included between January 1,2011 and December 31,2011. All the data were collected retrospectively from clinical records by a prospectively designed questionnaire. The data collected from each NICU transmitted to the main institution where the results were aggregated and analyzed. Categorical variables were performed with Pearson Chi-square test. Binary Logistic regression analysis was used to detect risk factors. Results： A total of 258 ELBW infants were admitted to 26 NICUs, of whom the mean gestational age （GA） was 28.1 ± 2.2 weeks, and the mean BW was 868 ± 97 g. The overall survival rate at discharge was 50.0%. Despite aggressive treatment 60 infants （23.3%） died and another 69 infants （26.7%） died after medical care withdrawal. Furthermore, the survival rate was significantly higher in coastal areas than inland areas （53.6% vs. 35.3%, P = 0.019）. BW 〈750 g and GA 〈28 weeks were the largest risk factors, and being small for gestational age was a protective factor related to mortality. Respiratory distress syndrome was the most common complication. The incidence of patent ductus arteriosus, intraventricular hemorrhage, periventricular leukomalacia, bronchopulmonary dysplasia, retinopathy of prematurity was 26.2%, 33.7%, 6.7%, 48.1%, and 41.4%, respectively. Ventilator associated pneumonia was the most common hospital acquired infection during hospitalization. Conclusions： Our study was the first survey that revealed the present status of ELBW infants in the mainland of China. The mortality and morbidity of ELBW infants remained high as compared to other developed countries.
基金supported by the National 863 Program of China(2012AA101502)the Special Fund for Agro-Scientific Research in the Public Interest, China (200903033)
文摘Sublethal effects of chlorantraniliprole to Helicoverpa armigera （Hiibner） larvae were evaluated through exposure of third instar larvae to the insecticide incorporated into an artificial diet. When larvae were fed on the insecticide-containing diet for 7 d, the LC10, LC20, LC40, and LC50values were 3.790, 7.977, 21.577, and 33.121 μg active ingredient L^-1, respectively. Chlorantraniliprole at sublethal concentrations significantly reduced the larval body mass, emergence ratio, adult longevity and egg hatching rate in both the parental and offspring generations. The pupation and copulation rate in the parental generation and the pupal mass in the offspring also strongly decreased. Reproduction was seriously disturbed in both the parental and offspring groups even when only one of the partners was exposed to chlorantraniliprole at larval stages. However, at the lowest concentration of exposure （LC^0）, offspring fecundity was strongly reduced only when both partners were exposed. The net reproductive rate （R0）, intrinsic rate of increase （rm）, and gross reproduction rate （GRR） at LC20, LC40 concentrations were significantly lower than that of the control. Post-exposure effects also included an extended larval developmental time and increased male proportion in both generations. The doubling time （Dt） at LC20, LC40 concentrations as well as gross reproduction rate （GRR） at LC10 concentration were also significantly increased. Chlorantraniliprole might have significant effects on H. armigera population dynamics even at sublethal concentrations on both parental and offspring generations.
基金supported by the National Natural Science Foundation of China(30270955)the Foundamental Research Funds for the Central Universities,China(XDJK2009B035)
文摘Estrogen plays an important role in regulating Sertoli cell number in the testis. The objective of the study was to identify whether 17β-estradiol affected the proliferation of cultured, immature boar Sertoli cells via the estrogen receptor β （ERβ） and the cAMP-extracellular signal-regulated kinase （ERK1/2） pathway. Low levels （10-10-10-8 mol L-1） of 17β-estradiol increased cell number, but high levels （10-7-10-6 mol L-1） decreased it （P〈0.05）. Sertoli cell number began to recover for an additional 24 h in the medium without 17β-estradiol （10-6 mol L-l） （P〉0.05）. The effects of 17β-estradiol （10-9 mol L-1） peaked at the first 24 h （P〈0.05）. 17β-estradiol activated ERK1/2 from 5 min to 24 h, but the activiy of ERK1/2 began to decrease after 4 h. Both PD98059 and U0126, two ERK inhibitors, blocked cell division （P〈0.05）. 17β-estradiol （10-10-10-6 mol L-1） dose-dependently increased cAMP production （P 〈 0.05）, and both 17β-estradiol （10-9 mol L-1） and forskolin, which increases cAMP levels, induced cell proliferation and activated ERK1/2 （P〈 0.05）. Rp-cAMP, an antagonist of cAMP, blocked this 17β-estradiol activity （P〈 0.05）. Two estrogen receptor antagonists, ICI 182780 and ERβ antagonist （ERβAnt）, reduced Sertoli cell number, cAMP production and ERK1/2 activation （P〈 0.05）, but ERaAnt did not （P〉 0.05）. Therefore, 17β- estradiol mainly promotes pig Sertoli cell proliferation via ERβ to induce cAMP production and ERK activation to promote cell proliferation.
基金The National Natural Science Foundation of China(82073144,J.W.)the Health Commission of Zhejiang Province(JBZX-202004,J.W.)the Huadong Medicine Joint Funds of the Zhejiang Provincial Natural Science Foundation of China(LHDMD22H310005,J.W.).
文摘Amino acids are the building blocks of protein synthesis.They are structural elements and energy sources of cells necessary for normal cell growth,differentiation and function.Amino acid metabolism disorders have been linked with a number of pathological conditions,including metabolic diseases,cardiovascular diseases,immune diseases,and cancer.In the case of tumors,alterations in amino acid metabolism can be used not only as clinical indicators of cancer progression but also as therapeutic strategies.
基金Project(2013CB036004)supported by the National Basic Research Program of ChinaProject(51378510)supported by the National Natural Science Foundation of ChinaProject(CX2014B069)supported by Hunan Provincial Innovation Foundation for Postgraduate,China
文摘High pressure and water-bearing caverns ahead of a karst tunnel face tend to cause geological disasters, such as water and mud bursts. So, the determination of safe thickness of the reserved rock plug is a key technical problem to be solved for karst tunnel construction. Based on the Hoek-Brown nonlinear failure criterion, the minimum safe thickness of rock plug was investigated in the light of the limit analysis theory. On the basis of the proposed failure mode, the expression of the minimum thickness for rock plug was obtained by means of upper bound theorem in combination with variational principle. The calculation results show the influence of each parameter on safe thickness and reveal the damage range of rock plug. The proposed method is verified by comparing the results with those of the drain cavern of Maluqing Tunnel. The research shows that with the increase of compressive strength and tensile strength as well as constant A of Hoek-Brown criterion, the safe thickness decreases, whereas with the increase of cavern pressure, tunnel diameter, and constant B from Hoek-Brown criterion, the safe thickness increases. Besides, the tensile strength, or constants A and B affect the shear failure angle of rock plug structure, but other parameters do not. In conclusion, the proposed method can predict the minimum safe thickness of rock plug, and is useful for water burst study and prevention measures of tunnels constructed in high-risk karst regions.
文摘Background Gastric cancer ranks high among the most common causes of cancer-related death worldwide. This study was designed to explore key genes involved in the progression of normal gastric epithelial cells to moderate gastric epithelial dysplasia （mGED） and to gastric cancer. Methods Twelve pairs of mGED tissues, gastric cancer tissues, and normal gastric tissues were collected by gastroscopy. Total RNA was then extracted and purified. After the addition of fluorescent tags, hybridization was carried out on a Gene chip microarray slide. Significance analysis of microarrays was performed to determine significant differences in gene expression between the different tissue types. Results Microarray data analysis revealed totally 34 genes that were expressed differently： 18 highly expressed （fold change 〉2; P 〈0.01） and 16 down-regulated （fold change 〉2; P 〈0.01）. Of the 34 genes, 24 belonged to several different functional categories such as structural molecule activity, extracellular regions, structural formation, cell death, biological adhesion, developmental processes, locomotion, and biological regulation that were associated with cancer. The remaining 10 genes were not involved in cancer research. Of these genes, the expression levels of Matrix metalloproteinase-12 （MMP12）, Caspase-associated recruitment domain 14 （CARD14）, and Chitinase 3-like 1 （CHI3L1） were confirmed by semi-quantitative RT-PCR. A two-way clustering algorithm divided the 36 samples into three categories and the overall correct classification efficiency was 80.6% （29/36）. Almost all of these genes （31/34） showed constant changes in the process of normal gastric epithelial cells to mGED to gastric cancer. Conclusions The results of this study provided global gene expression profiles during the development and progression from normal gastric epithelial cells to mGED to gastric cancer. These data may provide new insights into the molecular pathology of gastric cancer which may be useful for the detect
基金the National Key R&D Program of China(2016YFD0300503)the National Rice Industry Technology System,China(CARS-01-27)+3 种基金the National Natural Science Foundation of China(31971841)the Key Research Program of Jiangsu Province,China(BE2016344 and BE2018355)the earmarked fund for Jiangsu Agricultural Industry Technology System,China(JATS[2018]298)the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions,China。
文摘Indica-japonica hybrid rice(Oryza sativa L.) cultivars showed high yield potential and poor tasting quality when compared with common japonica rice cultivars. Large panicle is a prominent factor of high yield for indica-japonica hybrid rice cultivars, and the panicle weight varies greatly among different indica-japonica hybrid rice cultivars. It is important to research on yield and grain quality of different panicle weight indica-japonica hybrid rice cultivars. In this study, two different panicle types indica-japonica hybrid cultivars were used to research on the relation of yield and grain quality. The yields of two heavy panicle weights indica-japonica hybrid cultivars were significantly higher than that of two medium panicle weight rice cultivars. The cooking and eating quality and starch properties of different panicle type cultivars were evaluated. Yongyou 6715(medium panicle) and Yongyou 1852(heavy panicle) got the relatively higher cooking and eating quality. Rice cultivars with medium panicle weight had more large starch granules and higher relative crystallinity than cultivars with heavy panicle weight. Transition temperature and retrogradation enthalpy(ΔHret) of medium panicle type cultivars were significantly higher than that of heavy panicle type cultivars. There was no significant difference in amylose content among different panicle type cultivars. Protein content of heavy panicle type cultivar was higher than that of medium panicle type cultivar, and protein content is the main factor affect cooking and eating quality in this study. The cultivar Yongyou 6715 got the highest taste value with the lowest protein content. Thus, it is suggested that the emphasis on improving rice cooking and eating quality of indica-japonica hybrid rice cultivars is how to reduce the protein content in rice grain. According to the results of this study, medium panicle type with high grain weight is the desired panicle type for high quality indica-japonica hybrid rice breeding.
基金supported by the Natural Science Foundation Project of CQ CSTC,China(2010BB1138)the National Innovation Experiment Program for Undergraduate,China (091063530)
文摘Acetamiprid has a wide range of influence on physiological functions in mammals.The objective of this study was to examine the effect of acetamiprid on the reproductive function of male mice,and to study the role of oxidative stress in acetamiprid-induced damage to the testes.Fifty adult Kunmin male mice （25-30 g） were divided into five groups （n=10 per group）,i.e.,control,blank,acetamiprid alone,acetamiprid and vitamin E,and vitamin E alone.All groups were treated for 35 d.The results showed that acetamiprid significantly decreased the body weight and the weight of testosterone-responsive organs,such as the testis,epididymis,seminal vesicle,and prostate.Furthermore,acetamiprid also significantly reduced the serum testosterone concentration,and decreased sperm count,viability,motility,and the intactness of the acrosome （P〈0.05 for each parameter）.The mice treated with acetamiprid had damaged seminiferous tubules and Leydig cells based on the histological structure of testes;there was degeneration of the mitochondria and endoplasmic reticulum of Leydig cells.These deleterious effects of acetamiprid may be mediated by increasing oxidative stress,as acetamiprid increased malondialdehyde and nitric oxide in the testes,reduced the activity of catalase,glutathione peroxidase,superoxide dismutase,and activated p38.The concentration of acetamiprid in the testes was lower than that in liver,so did the concentrations of liver function tests,including aspartate transaminase （AST）,alanine transaminase （ALT） and alkaline phosphatase （ALP）,which suggest that male reproductive function may be affected through the indirect action of its metabolites.Vitamin E significantly ameliorated the effects of acetamiprid.We conclude that acetamiprid damages male reproductive function through inducing oxidative stress in the testes.
文摘At present, radical resection remains the only effective treatment for patients with hilar cholangiocarcinoma. The surgical approach for R0 resection of hilar cholangiocarcinoma is complex and diverse, but for the biliary reconstruction after resection, almost all surgeons use Roux-en-Y hepaticojejunostomy. A viable alternative to Roux-en-Y reconstruction after radical resection of hilar cholangiocarcinoma has not yet been proposed. We report a case of performing duct-to-duct biliary reconstruction after radical resection of Bismuth Ⅲa hilar cholangiocarcinoma. End-to-end anastomosis between the left hepatic duct and the distal common bile duct was used for the biliary reconstruction, and a singlelayer continuous suture was performed along the bile duct using 5-0 prolene. The patient was discharged favorably without biliary fistula 2 wk later. Evidence for tumor recurrence was not found after an 18 mo follow- up. Performing bile duct end-to-end anastomosis in hilar cholangiocarcinoma can simplify the complex digestive tract reconstruction process.
基金Project(51378514)supported by the National Natural Science Foundation of China
文摘A method of analyzing the stability of twin shallow tunnels was presented using both limit analysis with nonlinear failure criterion and reliability theory.In the condition of nonlinear failure criterion,the critical clear distancesof twin shallow tunnels were obtained by analyzing the change of surrounding pressure.A reliability model was established based on limit state equation,and the failure probability was solved by virtue of Monte Carlo method.Safety factor and corresponding clear distance of different safety levels were obtained by introducing a target reliability index.The scope of clear distance for different safety levels is described,which can be used as a supplement and improvement to the design codes of tunnels.
基金Projects(51804113,51434006,51874130)supported by the National Natural Science Foundation of ChinaProject(E51768)supported by the Doctoral Initiation Foundation of Hunan University of Science and Technology,China+1 种基金Project(E61610)supported by the Postdoctoral Research Foundation of Hunan University of Science and Technology,ChinaProject(E21734)supported by the Open Foundation of Work Safety Key Lab on Prevention and Control of Gas and Roof Disasters for Southern Coal Mines,China
文摘A new horn failure mechanism was constructed for tunnel faces in the soft rock mass by means of the logarithmic spiral curve. The seismic action was incorporated into the horn failure mechanism using the pseudo-static method. Considering the randomness of rock mass parameters and loads, a three-dimensional (3D) stochastic collapse model was established. Reliability analysis of seismic stability of tunnel faces was presented via the kinematical approach and the response surface method. The results show that, the reliability of tunnel faces is significantly affected by the supporting pressure, geological strength index, uniaxial compressive strength, rock bulk density and seismic forces. It is worth noting that, if the effect of seismic force was not considered, the stability of tunnel faces would be obviously overestimated. However, the correlation between horizontal and vertical seismic forces can be ignored under the condition of low calculation accuracy.
基金the 135 Project and Science-Technology Fund of Health Department of Jiangsu Province(Z200618)the Science-Technology Fund of Southeast University(XJ0690219)
文摘Background Pancreatic cancer is one of the most common tumors and has a 5-year survival for all stages of less than 5%. Most patients with pancreatic cancer are diagnosed at an advanced stage and therefore are not candidates for surgical resection. In recent years, investigation into alternative treatment strategies for this aggressive disease has led to advances in the field of gene therapy for pancreatic cancer. E. coil purine nucleoside phosphorylase/6-methylpurine deoxyribose （ePNP/MePdR） is a suicide gene/prodrug system where PNP enzyme cleaves nontoxic MePdR into cytotoxic membrane-permeable compounds 6-methylpurine （MeP） with high bystander activity, hTERT is expressed in cell lines and tissues for telomerase activity. In this study we examined the efficacy of ePNP under the control of hTERT promoter sequences and assessed the selective killing effects of the ePNP/prodrug MePdR system on pancreatic tumors. Methods Recombinant pET-PNP was established. The protein of E. coil PNPase was expressed and an antibody to E. coil PNPase was prepared. Transcriptional activities of hTERT promoter sequences were analyzed using a luciferase reporter gene. A recombinant phTERT-ePNP vector was constructed. The ePNP/MePdR system affects SW1990 human pancreatic cancer cell lines in vitro. Results The hTERT promoter had high transcriptional activity and conferred specificity on cancer cell lines. The antibody to E. coil PNPase was demonstrated to be specific for the ePNP protein. The MePdR treatment induced a high in vitro cytotoxicity on the sole hTERT-ePNP-producing cell lines and affected SW1990 cells in a dose-dependent manner. Conclusions The hTERT promoter control of the ePNP/MePdR system can provide a beneficial anti-tumor treatment in pancreatic cancer cell lines including a good bystander killing effect.
文摘Background Pancreatic cancer is one of the most lethal human cancers with a very low survival rate of 5 years. Conventional cancer treatments including surgery, radiation, chemotherapy or combinations of these show little effect on this disease. Several proteins have been proved critical to the development and the progression of pancreatic cancer. The aim of this study was to investigate the effect of resveratrol on apoptosis in pancreatic cancer cells. Methods Several pancreatic cancer cell lines were screened by resveratrol, and its toxicity was tested by normal pancreatic cells. Western blotting was then performed to analyze the molecular mechanism of resveratrol induced apoptosis of pancreatic cancer cell lines.
基金Projects(51974137,51774150)supported by the National Natural Science Foundation of ChinaProject(2020M671361)supported by China Postdoctoral Science Foundation。
文摘Hexagonal porous Nb2O5 was synthesized for the first time via a facile solid-state reaction.The structure and electrochemical properties have been optimized through tuning heating temperature.X-ray diffraction results indicate that pseudo hexagonal Nb2O5(TT-Nb2O5)and orthorhombic Nb2O5 have been synthesized at different temperatures.Hexagonal sheet and porous structure of Nb2O5 were characterized by scanning electron microscopy and N2-adsorption-desorption isotherms.The as-prepared TT-Nb2O5(heated at 600℃)shows the best performance with a remarkable charge capacity of 178 mA∙h/g at 0.2C,which is higher than that of T-Nb2O5.Even at 20℃,TT-Nb2O5 offers unprecedented rate capability up to 86 mA∙h/g.The high rate capacity is due to pseudocapacitive Li+intercalation mechanism of TT-Nb2O5.The reported results demonstrate that Nb2O5 with good crystal structure and high specific surface area is a powerful composite design for high-rate and safe anode materials.
基金National Natural Science Foundation of China (No.81000380H1204)Natural Science Foundation of Hubei Province,China (No.2008CDA053)Scientific Research Fund of the Ministry of Health,Hubei Province,China (No.QJX2010-53)
文摘AIM: To investigate whether bis (7)-tacrine, a multifunctional drug, inhibits N-methyl-D-aspartate (NMDA) -activated current in retinal ganglion cells (RGC) and provides neuroprotection against retinal cell damage. METHODS: Purified RGC cultures were obtained from retinas of 1-3 days old Sprague-Dawley (SD) rats, following a two-step immunopanning procedure. After 7 days of cultivation, the inhibition of NMDA-activated current by bis(7) -tacrine was measured by using patch-clamp recording techniques. In animal experiments, RGCs were damaged after intravitreal injection of NMDA (5 mu L, 40nmol) in adult rats. Bis (7)-tacrine(0.05, 0.1, 0.2mg/kg) or memantine(20mg/kg) was intraperitoneal administered to the rats fifteen minutes before intravitreally injection of NMDA. RGC damage was analyzed by histologic techniques, TUNEL and retrograde labeling techniques. RESULTS: Whole-cell patch-clamp recordings demonstrated that NMDA (30 mu mol/L) resulted in approximately -50 pA inward currents that were blocked by bis (7)-tacrine (1 mu mol/L). Histological examination and retrograde labeling analysis revealed that bis (7)-tacrine induced a significant neuroprotective effect against NMDA-induced cell damage 7 days after NMDA injection. TUNEL staining showed that pretreatment with bis(7)-tacrine was effective in ameliorating NMDA-induced apoptotic cell loss in the retinal ganglion cell layer 18 hours after injection. CONCLUSION: Bis (7)-tacrine possesses remarkable neuroprotective activities against retinal excitotoxicity through inhibition of NMDA receptors.
基金Supported by Department of General Surgery,Putuo Hospital,Shanghai University of Traditional Chinese Medicine,Shanghai,China
文摘Schwannomas are rarely observed in the gastrointestinal tract.The most common symptoms of a gastric schwannoma are abdominal pain or dyspepsia,gastrointestinal bleeding,and an abdominal mass.Many gastric schwannomas are asymptomatic and are discovered incidentally or at postmortem.The diagnosis of a schwannoma is based on immunohistochemical positivity for S-100 protein.Wepresent a case report of a rare complication of gastric schwannoma causing gastroduodenal intussusception that was successfully managed by a BillrothⅡdistal gastrectomy.In this rare case,the patient had intermittent,colicky abdominal pain,nausea,and vomiting for over 4wk accompanied by a weight loss.A diagnosis of gastric intussusception was made by computed tomography.A BillrothⅡdistal gastrectomy was then performed,and complete en bloc removal(R0 resection)was achieved.Pathology confirmed a gastric schwannoma through positive immunohistochemical staining for S-100 protein.
基金the Shanghai Soft X-ray Free-Electron Laser Facility beamline projectionfunded by the Major State Basic Research Development Program of China(No.2017YFA0504802)+1 种基金Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB 37040303)National Natural Science Foundation of China(No.21727817).
文摘The Shanghai soft X-ray free-electron laser(SXFEL)user facility project started in 2016 and is expected to be open to users by 2022.It aims to deliver ultra-intense coherent femtosecond X-ray pulses to five endstations covering a range of 100–620 eV for ultrafast X-ray science.Two undulator lines are designed and constructed,based on different lasing modes:self-amplified spontaneous emission and echo-enabled harmonic generation.The coherent scattering and imaging(CSI)endstation is the first of five endstations to be commissioned online.It focuses on high-resolution single-shot imaging and the study of ultrafast dynamic processes using coherent forward scattering techniques.Both the single-shot holograms and coherent diffraction patterns were recorded and reconstructed for nanoscale imaging,indicating the excellent coherence and high peak power of the SXFEL and the possibility of‘‘diffraction before destruction’’experiments at the CSI endstation.In this study,we report the first commissioning results of the CSI endstation.
基金This work was partially supported by Shanghai Municipal Health Bureau(No.2011239)the National Science and Technology Supporting Program of China(No.2012BAI17B02).
文摘The current study is to observe the effect of the locking system strengthened by biomimetic mineralized collagen putty for the treatment of senile proximal humeral osteoporotic fractures.From January 2012 to December 2015,80 cases of senile patients with osteoporotic proximal humeral fractures were randomly divided into an observation group and a control group,each group with a total of 40 cases.The control group was simply treated with locking plate.The observation group was treated with locking plate in combination with biomimetic mineralized collagen putty.The therapeutic effect thereby was observed.The excellent and satisfactory rate was 90%in observation group and was 72.5%in control group.The difference between the two groups was statistically significant(χ^(2)=5.3312,P<0.05).The fracture healing time was 11.8263.62 weeks in observation group and 19.7865.46 weeks in control group.The shoulder joint function score was 89.6368.12 in observation group and 76.9268.18 in control group.There was significant difference between the two groups(t=7.1272;12.7834,P<0.05).The complication rate was 10%in the observation group and 32.5%in the control group(χ^(2)=7.3786,P<0.05).Locking system strengthened by biomimetic mineralized collagen putty has advantages such as accelerating healing of senile proximal humeral fracture,improving the therapeutic effect,reducing the complications.As one of the optimal internal fixation method,it provides a new option for better treatment of senile osteoporotic fracture.
文摘The pressure and deflagration to detonation transition(DDT)characteristics of acetylene and oxygen flame were studied in a detonation tube.The pressure history and the flame velocity along the tube were measured with high frequency pressure transducers and ion probes.By analyzing the data recorded in the experiment,the detonation wave pressure,post wave pressure and DDT distance were obtained,together with the effects of the initial pressure varying from 2×10^(4)Pa to 10^(5)Pa,equivalence ration from 0.3 to 1.0,and mixture concentration from 60%to 100%.It was found that the detonation pressure was decreased respectively with the decrease of initial pressure,equivalence ratio and mixture concentration,but the DDT distance was enlarged.The DDT distance was found particularly sensitive to mixture concentration.
基金The project supported by the Natural Science Foundation of Anhui Province of China under Grant No. 01041188 and the Foundation of Classical Courses of Anhui Province
文摘By making use of extended mapping method and auxiliary equation for finding new periodic wave solu tions of nonlinear evolution equations in mathematical physics, we obtain some new periodic wave solutions for generalized Klein-Cordon equation and Benjamin equation, which cannot be found in previous work. This method also can be used to find new periodic wave solutions of other nonlinear evolution equations.
