期刊文献+
共找到82篇文章
< 1 2 5 >
每页显示 20 50 100
A study on the cognitive status of human papillomavirus among adult males in Tianjin based on the health belief model
1
作者 ming ma Fei-Fei Hong +3 位作者 Yu Liu Xin-Ran Huang Qi-Yun ma Peng-Xi Liu 《Infectious Diseases Research》 2024年第3期1-8,共8页
Background:To understand the health beliefs and knowledge of human papillomavirus among adult males in Tianjin.Methods:An online questionnaire survey was conducted from 18 January 2023 to 6 March 2023 using snowball s... Background:To understand the health beliefs and knowledge of human papillomavirus among adult males in Tianjin.Methods:An online questionnaire survey was conducted from 18 January 2023 to 6 March 2023 using snowball sampling method.Analyze the health belief scores and human papillomavirus(HPV)and HPV vaccine knowledge scores of adult males in Tianjin,and analyze their influencing factors.Results:A total of 388 adult males in Tianjin were surveyed,with an average total score of 3.23±0.04 for their health beliefs.Among them,the average scores for perceived severity,perceived susceptibility,perceived impairment,perceived benefit,and self-efficacy were 3.41±1.05,2.37±1.20,2.96±1.00,3.51±0.90,and 3.36±1.08,respectively.Multiple linear regression analyses showed education was a factor influencing health beliefs.The average total score of knowledge is 64.09±15.62,with 277 people scoring above 60,and a pass rate of 71.4%.Through multiple linear regression analysis,education level,emotional status,whether disease testing has been done,and whether family and friends have been diagnosed with HPV positive are the main influencing factors.Conclusion:The awareness rate of HPV among adult males in Tianjin is still acceptable,but there are still misconceptions.The overall level of health beliefs is moderate,and the perceived susceptibility level is low.It is necessary to strengthen health education on HPV related knowledge for males and improve their cognitive level. 展开更多
关键词 human papillomavirus Health Beliefs COGNITION adult male human papillomavirus vaccine
下载PDF
Identification and effective regulation of scarb1 gene involved in pigmentation change in autotetraploid Carassius auratus
2
作者 Xi-Dan Xu Yue Zhou +9 位作者 Chong-Qing Wang Xu Huang Kun Zhang Xiao-Wei Xu Li-Wen He Xin-Yue Zhang Xin-Zhu Fu ming ma Qin-Bo Qin Shao-Jun Liu 《Zoological Research》 SCIE CSCD 2024年第2期381-397,共17页
The autotetraploid Carassius auratus(4nRR,4n=200,RRRR)is derived from whole-genome duplication of Carassius auratus red var.(RCC,2n=100,RR).In the current study,we demonstrated that chromatophores and pigment changes ... The autotetraploid Carassius auratus(4nRR,4n=200,RRRR)is derived from whole-genome duplication of Carassius auratus red var.(RCC,2n=100,RR).In the current study,we demonstrated that chromatophores and pigment changes directly caused the coloration and variation of 4nRR skin(red in RCC,brownish-yellow in4nRR).To further explore the molecular mechanisms underlying coloration formation and variation in 4nRR,we performed transcriptome profiling and molecular functional verification in RCC and 4nRR.Results revealed that scarb1,associated with carotenoid metabolism,underwent significant down-regulation in 4nRR.Efficient editing of this candidate pigment gene provided clear evidence of its significant role in RCC coloration.Subsequently,we identified four divergent scarb1 homeologs in 4nRR:two original scarb1 homeologs from RCC and two duplicated ones.Notably,three of these homeologs possessed two highly conserved alleles,exhibiting biased and allelespecific expression in the skin.Remarkably,after precise editing of both the original and duplicated scarb1homeologs and/or alleles,4nRR individuals,whether singly or multiply mutated,displayed a transition from brownishyellow skin to a cyan-gray phenotype.Concurrently,the proportional areas of the cyan-gray regions displayed a gene-dose correlation.These findings illustrate the subfunctionalization of duplicated scarb1,with all scarb1genes synergistically and equally contributing to the pigmentation of 4nRR.This is the first report concerning the functional differentiation of duplicated homeologs in an autopolyploidfish,substantiallyenrichingour understanding of coloration formation and change within this group of organisms. 展开更多
关键词 Autopolyploidization Coloration change scarb1 Functional differentiation Genetic changes
下载PDF
A multi-mechanism numerical simulation model for CO_(2)-EOR and storage in fractured shale oil reservoirs
3
作者 Yuan-Zheng Wang Ren-Yi Cao +3 位作者 Zhi-Hao Jia Bin-Yu Wang ming ma Lin-Song Cheng 《Petroleum Science》 SCIE EI CAS CSCD 2024年第3期1814-1828,共15页
Under the policy background and advocacy of carbon capture,utilization,and storage(CCUS),CO_(2)-EOR has become a promising direction in the shale oil reservoir industry.The multi-scale pore structure distribution and ... Under the policy background and advocacy of carbon capture,utilization,and storage(CCUS),CO_(2)-EOR has become a promising direction in the shale oil reservoir industry.The multi-scale pore structure distribution and fracture structure lead to complex multiphase flow,comprehensively considering multiple mechanisms is crucial for development and CO_(2) storage in fractured shale reservoirs.In this paper,a multi-mechanism coupled model is developed by MATLAB.Compared to the traditional Eclipse300 and MATLAB Reservoir Simulation Toolbox(MRST),this model considers the impact of pore structure on fluid phase behavior by the modified Peng—Robinson equation of state(PR-EOS),and the effect simultaneously radiate to Maxwell—Stefan(M—S)diffusion,stress sensitivity,the nano-confinement(NC)effect.Moreover,a modified embedded discrete fracture model(EDFM)is used to model the complex fractures,which optimizes connection types and half-transmissibility calculation approaches between non-neighboring connections(NNCs).The full implicit equation adopts the finite volume method(FVM)and Newton—Raphson iteration for discretization and solution.The model verification with the Eclipse300 and MRST is satisfactory.The results show that the interaction between the mechanisms significantly affects the production performance and storage characteristics.The effect of molecular diffusion may be overestimated in oil-dominated(liquid-dominated)shale reservoirs.The well spacing and injection gas rate are the most crucial factors affecting the production by sensitivity analysis.Moreover,the potential gas invasion risk is mentioned.This model provides a reliable theoretical basis for CO_(2)-EOR and sequestration in shale oil reservoirs. 展开更多
关键词 CO_(2)-EOR CO_(2)storage Shale oil reservoir Complex fracture model Multiple mechanisms
下载PDF
The diagnostic value of tenascin-C in acute aortic syndrome
4
作者 ming ma Wei CHEN +4 位作者 Hai-Long CAO Jun PAN Qing ZHOU Xin-Long TANG Dong-Jin WANG 《Journal of Geriatric Cardiology》 SCIE CAS CSCD 2024年第3期359-368,共10页
OBJECTIVES Misdiagnosis of acute aortic syndrome(AAS)significantly increases mortality.Tenascin-C(TN-C)is an extracellular matrix glycoprotein related to cardiovascular injury.The elevation of TN-C in AAS and whether ... OBJECTIVES Misdiagnosis of acute aortic syndrome(AAS)significantly increases mortality.Tenascin-C(TN-C)is an extracellular matrix glycoprotein related to cardiovascular injury.The elevation of TN-C in AAS and whether it can discriminate suddenonset of acute chest pain in Chinese remains unclear.METHODS We measured the plasma concentration of TN-C by ELISA in a cohort of 376 patients with chest or back pain.Measures to discriminate AAS from acute coronary syndrome(ACS)were compared and calculated.RESULTS From October 2016 to September 2021,376 undiagnosed patients with chest or back pain were enrolled.166 of them were finally diagnosed as AAS,100 were ACS and 110 without cardiovascular diseases(NCV).TN-C was significantly elevated in AAS at 18.18 ng/mL(IQR:13.10–27.68)compared with 7.51 ng/mL(IQR:5.67–11.38)in ACS(P<0.001)and 3.68 ng/mL(IQR:2.50–5.29)in NCV(P<0.001).There was no significant difference in TN-C level among the subtypes of AAS.Of the 166 AAS patients,the peaked level of TN-C was at acute stage(P=0.012),then a slight of decrease was observed at subacute stage.The area under receiver operating characteristic curve for AAS patients versus NCV was 0.979(95%CI:0.964-0.994)for TN-C.At a cutoff level of 11.474 ng/mL,TN-C has a sensitivity of 76.0%,specificity of 85.5%,accuracy of 82.0%,positive predictive value(PPV)of 76.0%,negative predictive value(NPV)of 85.5%.Diagnostic performance of TN-C was superior to D-dimer and hs-cTnT.CONCLUSIONS The concentration of serum TN-C in AAS patients was significantly higher than that in ACS patients and NCV.TN-C could be a new biomarker to distinguish AAS patients in the early stage after symptoms onset from other pain diseases. 展开更多
关键词 ACUTE CARDIOVASCULAR ELEVATED
下载PDF
Effects of Thermal and Hydric Conditions on Egg Incubation and Hatchling Phenotypes in Two Phrynocephalus Lizards 被引量:5
5
作者 Xiaolong TANG Feng YUE +3 位作者 ming ma Ningbo WANG Jianzheng HE Qiang CHEN 《Asian Herpetological Research》 SCIE 2012年第3期184-191,共8页
Flexible-shelled eggs of the lizards Phrynocephalus przewalskii and P. versicolor were incubated under different thermal and hydric conditions to elicit the effects of incubation environment on hatching success, embry... Flexible-shelled eggs of the lizards Phrynocephalus przewalskii and P. versicolor were incubated under different thermal and hydric conditions to elicit the effects of incubation environment on hatching success, embryonic development and duration as well as hatchling phenotypes. Embryogenesis of the two species was not sensitive to changes in the hydric environment except P. przewalskii incubated in 30°C group. Temperature significantly altered the duration of embryogenesis, with cooler temperatures leading to a longer incubation period. Hatching success was greater at 26 and 30°C than at 34°C. The hatchlings incubated at 26 and 30°C had longer snout-vent length, larger body mass, and better locomotor performance than those incubated at 34°C. Compared to P. przewalskii, P. versicolor had a shorter incubation period and yielded smaller hatchlings, which then had a higher survival rate in cooler and drier habitats. We conclude that an incubation temperature of 30°C would produce the best balance among developmental rate, hatching success, and post-hatching performance. We speculate that the upper temperature limit for incubation of P. versicolor eggs may be slightly higher than 34°C. 展开更多
关键词 egg incubation hatchling phenotypes post-hatching performance Phrynocephalus przewalskii Phrynocephalus versicolor
下载PDF
Copy number alteration profiling facilitates differential diagnosis between ossifying fibroma and fibrous dysplasia of the jaws 被引量:4
6
作者 ming ma Lu Liu +7 位作者 Ruirui Shi Jianyun Zhang Xiaotian Li Xuefen Li Jiaying Bai Jianbin Wang Yanyi Huang Tiejun Li 《International Journal of Oral Science》 SCIE CAS CSCD 2021年第2期200-209,共10页
Ossifying fibroma(OF)and fibrous dysplasia(FD)are two fibro-osseous lesions with overlapping clinicopathological features,making diagnosis challenging.In this study,we applied a whole-genome shallow sequencing approac... Ossifying fibroma(OF)and fibrous dysplasia(FD)are two fibro-osseous lesions with overlapping clinicopathological features,making diagnosis challenging.In this study,we applied a whole-genome shallow sequencing approach to facilitate differential diagnosis via precise profiling of copy number alterations(CNAs)using minute amounts of DNA extracted from morphologically correlated microdissected tissue samples.Freshly frozen tissue specimens from OF(n=29)and FD(n=28)patients were obtained for analysis.Lesion fibrous tissues and surrounding normal tissues were obtained by laser capture microdissection(LCM),with~30–50 cells(5000–10000µm2)per sample.We found that the rate of recurrent CNAs in OF cases was much higher(44.8%,13 of 29)than that in FD cases(3.6%,1 of 28).Sixty-nine percent(9 of 13)of the CNA-containing OF cases involved segmental amplifications and deletions on Chrs 7 and 12.We also identified eight CNA-associated genes(HILPDA,CALD1,C1GALT1,MICALL2,PHF14,AIMP2,MDM2,and CDK4)with amplified expression,which was consistent with the copy number changes.We further confirmed a jaw lesion with a previous uncertain diagnosis due to its ambiguous morphological features and the absence of GNAS mutation as OF based on the typical Chr 12 amplification pattern in its CNA profile.Moreover,analysis of a set of longitudinal samples collected from an individual with a cellular lesion in suspicion of OF at the first surgery,recurrence and the latest malignant transformation revealed identical CNA patterns at the three time points,suggesting that copy number profiling can be used as an important tool to identify borderline lesions or lesions with malignant potential.Overall,CNA profiling of fibro-osseous lesions can greatly improve differential diagnosis between OF and FD and help predict disease progression. 展开更多
关键词 DIAGNOSIS PRECISE PROFILING
下载PDF
Tocilizumab promotes corneal allograft survival in rats by modulating Treg-Th17 balance 被引量:4
7
作者 Xiao-Song Wu Xiao-Li Lu +3 位作者 Jing Wu ming ma Jian Yu Zhen-Yu Zhang 《International Journal of Ophthalmology(English edition)》 SCIE CAS 2019年第12期1823-1831,共9页
AIM: To examine the therapeutic effects of tocilizumab on experimental corneal transplantation and its effect on Treg/Th17 balance. METHODS: Allograft corneal graft was performed between host Sprague Dawley and Wistar... AIM: To examine the therapeutic effects of tocilizumab on experimental corneal transplantation and its effect on Treg/Th17 balance. METHODS: Allograft corneal graft was performed between host Sprague Dawley and Wistar donor rats.The rats were randomly divided into four groups: normal,autograft, allograft, and allograft treated with tocilizumab.Kaplan-Meier was performed to draw the survival curve.The protein levels of interleukin-17A(IL-17A), vascular endothelial growth factor(VEGF), and forkhead box protein3(Foxp3) were measured by immunohistochemistry.The mRNA levels of IL-17A, VEGF, retinoid-related orphan receptor gammat(RORγt), interleukin-6(IL-6) and Foxp3 were detected by reverse transcription real-time polymerase chain reaction(RT-PCR). The Treg and Th17 cells were investigated by flow cytometry. RESULTS: The survival time of tocilizumab group was(24±1.27 d) longer than that of allograft group(10±0.55 d).Moreover, immunohistochemical examination revealed that IL-17A and VEGF protein levels in the allograft group were significantly higher than that of tocilizumab group(P<0.01),while Foxp3 levels in the allograft group was significantly lower than that of the tocilizumab treated group(P<0.001).Flow cytometry showed that the number of Th17 cellsin allograft group was significantly higher than that in tocilizumab group(P<0.001). Meanwhile, the number of Tregs was significantly lower than in tocilizumab group(P<0.001). Simultaneously, Foxp3 m RNA expression level in corneal tissues of tocilizumab treated group was significantly higher than other groups(P<0.001). CONCLUSION: These findings suggest that tocilizumab may promote corneal allograft survival, possibly by modulating Treg-Th17 balance. 展开更多
关键词 TOCILIZUMAB corneal transplantation TH17/TREG RATS
下载PDF
7, 8-dihydroxycoumarin improves neurological function in a mouse model of sciatic nerve injury 被引量:2
8
作者 Jianshi Du Qing Zhao +2 位作者 Yingli Zhang Yu Wang ming ma 《Neural Regeneration Research》 SCIE CAS CSCD 2012年第6期445-450,共6页
In the present study, a mouse model of sciatic nerve injury was treated with intraperitoneal injection of 7, 8-dihydroxycoumarin (10, 5, or 2.5 mg/kg per day). Western blot and real-time PCR results showed that grow... In the present study, a mouse model of sciatic nerve injury was treated with intraperitoneal injection of 7, 8-dihydroxycoumarin (10, 5, or 2.5 mg/kg per day). Western blot and real-time PCR results showed that growth associated protein 43 expression was significantly increased in the L4-6 segments of the spinal cord. The amplitude and velocity of motor nerve conduction in the sciatic nerve were significantly increased in model mice. In addition, the appearance of the myelin sheath in the injured sciatic nerve was regular, with an even thickness and clear outline, and the surrounding fibroplasia was not obvious. Our results indicate that 7, 8-dihydroxycoumarin can promote the repair of injured nerve by upregulating growth associated protein 43 expression in the corresponding spinal cord segments of mice with sciatic nerve injury. 展开更多
关键词 7 8-dihydroxycoumarin growth associated protein 43 sciatic nerve peripheral nerve injury neural regeneration
下载PDF
Magnetic Solid-Phase Extraction of Phthalate Esters from Environmental Water Samples using Fibrous Phenyl-functionalized Fe3O4@SiO2@KCC-1 被引量:2
9
作者 Xue-zheng Zhou Xiang-yang Yan +6 位作者 Ling Zhu ming ma Ya Dai Chang-guo Wang Li-jun Zhu Ke-jie Yu Shao-min Liu 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2020年第6期749-756,I0003,共9页
A new kind of phenyl-functionalized magnetic fibrous mesoporous silica(Fe3 O4@Si O2@KCC-1-phenyl) was prepared by copolymerization as an efficient adsorbent for the magnetic extraction of phthalate esters from environ... A new kind of phenyl-functionalized magnetic fibrous mesoporous silica(Fe3 O4@Si O2@KCC-1-phenyl) was prepared by copolymerization as an efficient adsorbent for the magnetic extraction of phthalate esters from environmental water samples. The obtained Fe3 O4@Si O2@KCC-1-phenyl showed monodisperse fibrous spherical morphology, fairly strong magnetic response(29 emu/g), and an abundant π-electron system, which allowed rapid isolation of the Fe3 O4@Si O2@KCC-1-phenyl from solutions upon applying an appropriate magnetic field. Several variables that affect the extraction efficiency of the analytes,including the type of the elution solvent, amount of adsorbent, extraction time and reusability, were investigated and optimized. Under optimum conditions, the Fe3 O4@Si O2@KCC-1-phenyl was used for the extraction of four phthalate esters from environmental water samples followed by high-performance liquid chromatographic analysis. Validation experiments indicated that the developed method presented good linearity(0.1-20 ng/m L), low limit of detection(7.5-29 μg/L, S/N =3). The proposed method was applied to the determination of phthalate esters in different real water samples, with relative recoveries of 93%-103.4%and relative standard deviation of 0.8%-8.3%. 展开更多
关键词 Fibrous mesoporous silica Phenyl-functionalized Magnetic solid-phase ex-traction High performance liquid chromatography Phthalate esters Environmental water
下载PDF
Magnetic nanocomposites of Fe_3O_4/SiO_2-FITC with pH-dependent fluorescence emission 被引量:1
10
作者 Yu Zhang Shang Wen Yan Gong +4 位作者 Lu Jin Shuang man Li Zhong Ping Chen ming ma Ning Gu 《Chinese Chemical Letters》 SCIE CAS CSCD 2009年第8期969-972,共4页
This paper describes the formation of magnetic and fluorescent nanocomposite particles which consist of superparamagnetic Fe3O4 core, SiO2 shell and organic dye (FITC) coating layer on their surface. The obtained na... This paper describes the formation of magnetic and fluorescent nanocomposite particles which consist of superparamagnetic Fe3O4 core, SiO2 shell and organic dye (FITC) coating layer on their surface. The obtained nanocomposites possess typical superparamagnetism and exhibit clear green fluorescence image. And their fluorescence emission is pH-dependent, which would be applied to pH sensing. ?2009 Yu Zhang. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All fights reserved. 展开更多
关键词 NANOCOMPOSITES Cote-shell structure Magnetic nanoparticles FLUORESCENCE
下载PDF
Geographic range size patterns across plants and animals of Xinjiang,China
11
作者 LiPing Li ChunYan Zhang +15 位作者 Eimear Nic Lughadha Tarciso CCLeão Kate Hardwick YaoMin Zheng HuaWei Wan ming ma Nurbay Abudusalih Ying Hai Zhen Pu JiangShan Lai ZhanFeng Shen Li Liu Tuo Wang Yangming Jiang HuiHui Zhao QingJie Liu 《Research in Cold and Arid Regions》 CSCD 2022年第1期54-67,共14页
Patterns in species geographic range size are relatively well-known for vertebrates,but still poorly known for plants.Contrasts of these patterns between groups have rarely been investigated.With a detailed flora and ... Patterns in species geographic range size are relatively well-known for vertebrates,but still poorly known for plants.Contrasts of these patterns between groups have rarely been investigated.With a detailed flora and fauna distribution database of Xinjiang,China,we used regression methods,redundancy analysis and random forests to explore the relationship of environment and body size with the geographic range size of plants,mammals and birds in Xinjiang and contrast these patterns between plants and animals.We found positive correlations between species range size and body size.The range size of plants was more influenced by water variables,while that of mammals and birds was largely influenced by temperature variables.The productivity variable,i.e.,Enhanced Vegetation Index(EVI)was far more correlated with range size than climatic variables for both plants and animals,suggesting that vegetation productivity inferred from remote sensing data may be a good predictor of species range size for both plants and animals. 展开更多
关键词 range size body size Enhanced Vegetation Index(EVI) arid region CONSERVATION
下载PDF
The Equitable Total Chromatic Number of Some Join graphs
12
作者 Gang ma ming ma 《Open Journal of Applied Sciences》 2012年第4期96-99,共4页
A proper total-coloring of graph G is said to be?equitable if the number of elements (vertices and edges) in any?two color classes differ by at most one, which the required?minimum number of colors is called the equit... A proper total-coloring of graph G is said to be?equitable if the number of elements (vertices and edges) in any?two color classes differ by at most one, which the required?minimum number of colors is called the equitable total chromatic?number. In this paper, we prove some theorems on equitable?total coloring and derive the equitable total chromatic numbers?of Pm V?Sn, Pm V?Fn and Pm V Wn. 展开更多
关键词 JOIN GRAPH equitable TOTAL COLORING equitable TOTAL CHROMATIC NUMBERS
下载PDF
Effects of CH_(4)/CO_(2) multi-component gas on components and properties of tight oil during CO_(2) utilization and storage: Physical experiment and composition numerical simulation
13
作者 Zhi-Hao Jia Ren-Yi Cao +5 位作者 Bin-Yu Wang Lin-Song Cheng Jin-Chong Zhou Bao-Biao Pu Fu-Guo Yin ming ma 《Petroleum Science》 SCIE EI CAS CSCD 2023年第6期3478-3487,共10页
An essential technology of carbon capture, utilization and storage-enhanced oil recovery (CCUS-EOR) for tight oil reservoirs is CO_(2) huff-puff followed by associated produced gas reinjection. In this paper, the effe... An essential technology of carbon capture, utilization and storage-enhanced oil recovery (CCUS-EOR) for tight oil reservoirs is CO_(2) huff-puff followed by associated produced gas reinjection. In this paper, the effects of multi-component gas on the properties and components of tight oil are studied. First, the core displacement experiments using the CH_(4)/CO_(2) multi-component gas are conducted to determine the oil displacement efficiency under different CO_(2) and CH_(4) ratios. Then, a viscometer and a liquid density balance are used to investigate the change characteristics of oil viscosity and density after multi-component gas displacement with different CO_(2) and CH_(4) ratios. In addition, a laboratory scale numerical model is established to validate the experimental results. Finally, a composition model of multi-stage fractured horizontal well in tight oil reservoir considering nano-confinement effects is established to investigate the effects of multi-component gas on the components of produced dead oil and formation crude oil. The experimental results show that the oil displacement efficiency of multi-component gas displacement is greater than that of single-component gas displacement. The CH_(4) decreases the viscosity and density of light oil, while CO_(2) decreases the viscosity but increases the density. And the numerical simulation results show that CO_(2) extracts more heavy components from the liquid phase into the vapor phase, while CH_(4) extracts more light components from the liquid phase into the vapor phase during cyclic gas injection. The multi-component gas can extract both the light components and the heavy components from oil, and the balanced production of each component can be achieved by using multi-component gas huff-puff. 展开更多
关键词 Multi-component gas Properties and components Core displacement experiment Nano-confinement numerical simulation CO_(2)utilization and storage
下载PDF
BIFURCATION ANALYSIS IN A PREDATOR-PREY MODEL WITH AN ALLEE EFFECT AND A DELAYED MECHANISM
14
作者 李丹阳 刘华 +3 位作者 张濠天 马明 叶勇 魏玉梅 《Acta Mathematica Scientia》 SCIE CSCD 2023年第3期1415-1438,共24页
Regarding delay-induced predator-prey models, much research has been done on delayed destabilization, but whether delays are stabilizing or destabilizing is a subtle issue. In this study, we investigate predator-prey ... Regarding delay-induced predator-prey models, much research has been done on delayed destabilization, but whether delays are stabilizing or destabilizing is a subtle issue. In this study, we investigate predator-prey dynamics affected by both delays and the Allee effect. We analyze the consequences of delays in different feedback mechanisms. The existence of a Hopf bifurcation is studied, and we calculate the value of the delay that leads to the Hopf bifurcation. Furthermore, applying the normal form theory and a center manifold theorem, we consider the direction and stability of the Hopf bifurcation. Finally, we present numerical experiments that validate our theoretical analysis. Interestingly, depending on the chosen delay mechanism, we find that delays are not necessarily destabilizing. The Allee effect generally increases the stability of the equilibrium, and when the Allee effect involves a delay term, the stabilization effect is more pronounced. 展开更多
关键词 DELAYS Allee effect Hopf bifurcation STABILITY
下载PDF
A comparative study of the electrical characteristics of positive and negative narrow bipolar events
15
作者 FeiFan Liu BaoYou Zhu +3 位作者 HeLin Zhou GaoPeng Lu ming ma JiuHou Lei 《Earth and Planetary Physics》 CAS CSCD 2023年第6期675-683,共9页
Narrow bipolar events(NBEs)are intriguing intra-cloud discharge that have attracted enormous interest in the lightning community.They come with two polarities that dominate at different altitudes in thunderclouds.The ... Narrow bipolar events(NBEs)are intriguing intra-cloud discharge that have attracted enormous interest in the lightning community.They come with two polarities that dominate at different altitudes in thunderclouds.The sources of negative NBEs are usually located near the top of thunderclouds;those of positive NBEs are at the middle levels.NBEs may occur at the onset of lightning.The electrical properties of NBEs remain poorly understood.We present here the first comparative study of the electrical characteristics of negative and positive NBEs.To derive electrical parameters from the fast electric field change waveforms of 1673 positive NBEs and 364 negative NBEs recorded by the Jianghuai Area Sferic Array(JASA)in China,we use an improved method based on the transmission line model.This approach concludes that negative NBEs occurring at high altitudes tend to produce a narrower current pulse and take a shorter time to traverse the channel than their positive counterparts.Moreover,compared to positive NBEs,a larger portion of negative NBEs are associated with slightly greater peak current moments but smaller overall charge moments.The differences reported herein between electrical properties of negative and positive NBEs suggest that charge distribution in NBE-producing thunderstorms tends to vary systematically with altitude. 展开更多
关键词 LIGHTNING THUNDERSTORM narrow bipolar events
下载PDF
Advances in CIGS thin film solar cells with emphasis on the alkali element post-deposition treatment
16
作者 Chenchen Zhao Shen Yu +10 位作者 Wei Tang Xinye Yuan Hongfei Zhou Tongqing Qi Xue Zheng De Ning ming ma Junyi Zhu Jie Zhang Chunlei Yang Weimin Li 《Materials Reports(Energy)》 2023年第3期24-40,共17页
In the past tens of years,the power conversion efficiency of Cu(In,Ga)Se2(CIGS)has continuously improved and been one of the fastest growing photovoltaic technologies that can also help us achieve the goal of carbon e... In the past tens of years,the power conversion efficiency of Cu(In,Ga)Se2(CIGS)has continuously improved and been one of the fastest growing photovoltaic technologies that can also help us achieve the goal of carbon emissions reduction.Among several key advances,the alkali element post-deposition treatment(AlK PDT)is regarded as the most important finding in the last 10 years,which has led to the improvement of CIGS solar cell efficiency from 20.4%to 23.35%.A profound understanding of the influence of alkali element on the chemical and electrical properties of the CIGS absorber along with the underlying mechanisms is of great importance.In this review,we summarize the strategies of the alkali element doping in CIGS solar cell,the problems to be noted in the PDT process,the effects on the CdS buffer layer,the effects of different alkali elements on the structure and morphology of the CIGS absorber layer,and retrospect the progress in the CIGS solar cell with emphasis on the alkali element post deposition treatment. 展开更多
关键词 CIGS solar cells Post-deposition treatment Alkali element Efficiency Absorber
下载PDF
止血绫修复内镜黏膜下剥离术后创面的应用研究 被引量:3
17
作者 陈钟 蔡艺玲 +6 位作者 马明 韩忠政 张秦 王君尧 唐庆林 张华玉 张鸣青 《中国内镜杂志》 北大核心 2017年第5期28-33,共6页
目的探讨止血绫在内镜黏膜下剥离术(ESD)后预防创面出血及创面修复中的临床应用价值。方法采用活体兔对比研究手术切开兔胃后的出血量(ml),并以活体猪为研究对象行结肠ESD手术,实验组术后用止血绫进行覆盖,对照组创面则不予以处理,术后... 目的探讨止血绫在内镜黏膜下剥离术(ESD)后预防创面出血及创面修复中的临床应用价值。方法采用活体兔对比研究手术切开兔胃后的出血量(ml),并以活体猪为研究对象行结肠ESD手术,实验组术后用止血绫进行覆盖,对照组创面则不予以处理,术后3天、1周、2周及4周分别进行内镜及病理学检查,比较两组的创面出血及组织愈合情况。结果兔胃出血量对比实验中,实验组出血量明显低于对照组,实验猪行结肠ESD术后创面均成功覆盖止血绫。行内镜检查及病理检查,实验组存在修复优势。实验组与对照组总共24处创面中,均未出现感染、穿孔等实验相关的不良事件。结论止血绫在临床ESD后创面修复中具有潜在的应用价值。 展开更多
关键词 内镜黏膜下剥离术 动物模型 止血绫 创面修复
下载PDF
新疆南部黑颈鹤种群分布及数量 被引量:2
18
作者 马鸣 张同 徐峰 《Zoological Research》 SCIE CAS CSCD 北大核心 2014年第S01期105-110,共6页
黑颈鹤(Grus nigricollis)是青藏高原特有物种,在新疆主要分布在与青海、西藏、甘肃相邻的阿尔金山、昆仑山、帕米尔高原及喀喇昆仑山地区。2010—2013年,采用路线调查法、直接计数法和扫描观测法等,对该地区黑颈鹤的地理分布、家庭组... 黑颈鹤(Grus nigricollis)是青藏高原特有物种,在新疆主要分布在与青海、西藏、甘肃相邻的阿尔金山、昆仑山、帕米尔高原及喀喇昆仑山地区。2010—2013年,采用路线调查法、直接计数法和扫描观测法等,对该地区黑颈鹤的地理分布、家庭组成、种群结构、数量动态、繁殖行为、生存现状等进行了详细调查。在乌尊硝尔、玉素甫阿勒克、鸭子泉、祁曼塔格、吐拉牧场等地的湿地中,都有黑颈鹤分布。该次调查样点25个及观测164次,共记录到黑颈鹤173只,其中,在依协克帕提湿地(N37°18',E90°20',海拔3903 m),最多一次记录到126只黑颈鹤集群,估计在整个昆仑山—阿尔金山地区共有黑颈鹤220~260只。结合早期的科学考察记录,推测整个新疆的黑颈鹤数量在300~380只。2011年11月6日黑颈鹤全部迁徙离开这一地区,与到达贵州、云南越冬地的时间衔接。此外,我们还在阿尔金山保护区观察到灰鹤3只和蓑羽鹤1只。鹤类面临的威胁来自违法采矿、过度放牧、生态旅游、盗猎(包括捡蛋、毁巢)。 展开更多
关键词 黑颈鹤 分布 数量 生存状况 昆仑山
下载PDF
扩大碟形术加带血管蒂腓骨游离移植治疗胫骨慢性骨髓炎 被引量:2
19
作者 傅晨 杨成勇 +7 位作者 张明建 马明 沈书明 王金光 陆长美 张建民 陈群 王汝渔 《亚洲外科手术病例研究》 2012年第3期13-17,共5页
目的:探索扩大碟形术加带血管蒂腓骨游离移植治疗胫骨慢性骨髓炎的可行性和疗效。方法:12例胫骨慢性骨髓炎患者行胫骨骨髓炎病灶清除、扩大碟形术,取对侧带血管蒂腓骨游离移植,修复患侧胫骨切除后缺损,置冲洗引流管。结果:经2~3年随访,... 目的:探索扩大碟形术加带血管蒂腓骨游离移植治疗胫骨慢性骨髓炎的可行性和疗效。方法:12例胫骨慢性骨髓炎患者行胫骨骨髓炎病灶清除、扩大碟形术,取对侧带血管蒂腓骨游离移植,修复患侧胫骨切除后缺损,置冲洗引流管。结果:经2~3年随访,优5例,良6例,中1例,绝大部分病例胫骨碟形化部经重建修复后在13~18月内满意愈合,恢复行走功能,少部分病例术后切口有轻微感染。经随访发现,随着骨缺损部逐渐愈合,移植来的腓骨会逐渐塑形、增粗,并与受区胫骨融为一体。结论:扩大碟形术加带血管蒂腓骨游离移植治疗胫骨慢性骨髓炎具有可行性和较满意之疗效,强调骨髓炎手术适应症的正确把握和感染病灶清除的适当彻底,须注意围手术期全程的规范化管理。 展开更多
关键词 腓骨 移植 骨髓炎 显微外科手术
下载PDF
The Influence of HIF-1α Expression on Apoptosis and Number of T Lymphocyte in Peyer’s Patches after Burn with Delayed Fluid Resuscitation in Rats at Plateau
20
作者 Cheng Zhang Yi Liu +1 位作者 ming ma Shifan Zhang 《Surgical Science》 2016年第9期390-399,共10页
Objective: To research the expression of hypoxia inducible factor-1 alpha (HIF-1 alpha) on the apoptosis and number of T lymphocyte in Peyer’s patches after severe burn on plateau in rats. Methods: Wistar rats (n = 1... Objective: To research the expression of hypoxia inducible factor-1 alpha (HIF-1 alpha) on the apoptosis and number of T lymphocyte in Peyer’s patches after severe burn on plateau in rats. Methods: Wistar rats (n = 130) were subjected to deep thickness burn injury (30% TBSA, III degree), at two different altitudes. 60 of them were given delayed fluid resuscitation (DFR, n = 30 at each altitude) 6 h after burn at different altitude;60 of them were carried out immediate fluid resuscitation (IFR, n = 30 at each altitude);10 rats were subjected to 37°C warm water as sham burn (SG, n = 10). The Peyer’s patches were harvested from the ileum of rats at different time point after burn respectively. The expression of HIF-1 alpha, CD3(+) and the apoptosis and number of T lymphocyte in Peyer’s patches were detected by tissue microarray technology and immunohistochemistry. Results: The apoptosis was higher in DFR group than that in IFR group. The increase in HIF-1 alpha expression was observed mainly on cell nucleus in T lymphocytes. The expression levels of HIF-1 alpha in Peyer’s patches were much higher in DFR group and IFR group than those in SG, and they were higher at high altitude (3848 metres) than those at lower altitude (1517 metres), and also higher in DFR group compared with IFR group (all P < 0.05). The expression levels of CD3<sup>+</sup> in Peyer’s patches were much lower in DFR group and IFR group than those in sham group, and the lowest value appeared at 12 hours after burn (all P < 0.05). Conclusion: High expression of HIF-1 alpha may induce the apoptosis of T lymphocytes in Peyer’s patches after severe burn with delayed fluid resuscitation in rats at plateau. 展开更多
关键词 Delayed Fluid Resuscitation Peyer’s Patches APOPTOSIS HIF-1Α BURN PLATEAU
下载PDF
上一页 1 2 5 下一页 到第
使用帮助 返回顶部