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基于肌电和优化方法的关节肌力分布模型 被引量:5
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作者 李翰君 刘卉 +1 位作者 张新 于冰 《中国运动医学杂志》 CAS CSCD 北大核心 2014年第10期981-987,共7页
目的:建立基于肌电信号的关节肌力分布模型来得到运动过程中膝关节的肌肉力。方法:测试9名运动员的急停起跳和变向动作,得到了人体下肢运动学、动力学数据以及膝关节周围7块肌肉的肌电。采用急停起跳动作得到肌肉最佳长度,代入变向动作... 目的:建立基于肌电信号的关节肌力分布模型来得到运动过程中膝关节的肌肉力。方法:测试9名运动员的急停起跳和变向动作,得到了人体下肢运动学、动力学数据以及膝关节周围7块肌肉的肌电。采用急停起跳动作得到肌肉最佳长度,代入变向动作中计算膝关节力矩。结果:在急停起跳动作中模拟的肌肉力矩与逆动力学得到的关节净力矩相似度很高。采用急停起跳得到肌肉最佳长度预测变向动作的肌肉力矩,精度仅轻微下降。结论:本建模方法可以估算活体运动时的肌肉力。 展开更多
关键词 肌电驱动 骨骼肌
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长枪管模设计之特点
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作者 张少飞 《科技创新导报》 2012年第17期19-19,共1页
在塑胶产品的模具设计中,设计长枪管模具的行位(滑块)与普通模行位(滑块)是不同的。本文介绍一款长枪管模的设计。
关键词 倒扣 行位(滑块) 模肉 斜边 刀路 抛光
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Research on the Effect of Microbial Fermentation Feeds on Slaughter Performance and Meat Quality in Pig with Large-scale Feeding 被引量:9
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作者 林标声 罗建 +1 位作者 李益明 杨小燕 《Agricultural Science & Technology》 CAS 2016年第10期2329-2331,2382,共4页
In this paper, Duroc-lanndrae-Yorkshire crossbred piggy of born at 75 days of age, bouncing with health and similar body weight were randomly divided into experimental group (136 pigs) and control group (136 pigs)... In this paper, Duroc-lanndrae-Yorkshire crossbred piggy of born at 75 days of age, bouncing with health and similar body weight were randomly divided into experimental group (136 pigs) and control group (136 pigs). Pigs in control group were fed with conventional diets, and 4% microbial fermentation feeds were added to the basal diet of experimental group to research on the effect of performance and meat quality of pig breeding. The results indicated that after feeding 106 d, compared to control group, the slaughter performance, meat quality and content of fatty acid and amino acid of experimental group were all better, its slaughter rate increased 1.53%, the carcass weight increased 2.75% and the backfat thickness decreased 0.02 cm. In addition, the pork meat in test group hadn't antibiotic and heavy metal residues, while it had higher color score, lower pH45min and pH24h value, better tenderness and rate of cooked meat and higher content of fatty acids, polyunsaturated fatty acids and amino acids. Microbial fermentation feed using in test group can significantly improved the flavor and aroma of pork, and eating this pork conducive more to human health. Thus, the application of microbial fermenta- tion feed can provide a more safe, healthy and nutritious flavor pork for human beings. 展开更多
关键词 Microbial fermentation feeds Large-scale feeding Slaughter performance Meat quality
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Digital Model of Human Lower Extremity Musculoskeletal System Based on CT & MRI 被引量:1
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作者 尚鹏 王成焘 王立 《Journal of Donghua University(English Edition)》 EI CAS 2004年第4期102-107,共6页
A new method to reconstruct a comparatively complete muscle model of the human lower limb from CT and MRI data is presented. Topological structure of more than fourteen muscles is built and coordinates of origin and i... A new method to reconstruct a comparatively complete muscle model of the human lower limb from CT and MRI data is presented. Topological structure of more than fourteen muscles is built and coordinates of origin and insertion points are given. Based on this model, straight-line model and centroid-line muscle model are acquired. Muscle force prediction is discussed according to the model reconstructed, and a multi-objective optimization method is put forward for evaluating muscle forces of the human lower extremity. 展开更多
关键词 SKELETON Muscular model muscle force optimization.
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Deletion of 93 bp Far-upstream Fragment of Rice Cytosolic Fructose- 1, 6-Bisphosphatase Promoter Completely Alter Its Expression Pattern 被引量:4
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作者 司丽珍 王力 +1 位作者 曹守云 储成才 《Acta Botanica Sinica》 CSCD 2002年第11期1339-1345,共7页
The 1 195 bp 5′ flanking region of rice ( Oryza sativa L.) cytosolic fructose_1, 6_bisphosphatase (cyFBPase) can direct tissue, cell specific expression in transgenic rice. In order to identify sequence elements ... The 1 195 bp 5′ flanking region of rice ( Oryza sativa L.) cytosolic fructose_1, 6_bisphosphatase (cyFBPase) can direct tissue, cell specific expression in transgenic rice. In order to identify sequence elements responsible for the regulation of mesophyll_specific expression, the 5′ flanking regions of -1 195 bp, -1 102 bp, -768 bp, and -644 bp upstream of the translation initiation ATG codon were fused to the reporter gene encoding β_glucuronidase (GUS) and transferred to rice via particle bombardment. Analysis of the 5′ promoter deletions identified that a 93 bp fragment between -1 195 bp and -1 102 bp is essential for directing mesophyll specific expression. High constitutive expression of GUS reporter gene was found in the -768 deletion lines and another two deletion series. These results indicate the great potential utility of the promoter in rice biotechnology. 展开更多
关键词 rice ( Oryza sativa ) cis _regulatory elements cytosolic fructose_1 6_bisphosphatase gene mesophyll_specific expression constitutive expression
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Establishment of a transplantation tumor model of human osteosarcoma in chick embryo 被引量:2
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作者 Jianping Wang Lihong Wang Lin Cai 《The Chinese-German Journal of Clinical Oncology》 CAS 2009年第9期531-536,共6页
Objective: We established a transplantation tumor model of human osteosarcoma in chick embryo, studied its morphological and biological characteristics, and observed its dynamic process of angiogenesis induction so th... Objective: We established a transplantation tumor model of human osteosarcoma in chick embryo, studied its morphological and biological characteristics, and observed its dynamic process of angiogenesis induction so that a simple and practical model can be provided for studying osteosarcoma. Methods: Human osteosarcoma cells at different concentrations were inoculated in chorioallantoic membrane (CAM) of chick embryos at different embryonic ages to observe the factors affecting the survival of the transplanted osteosarcoma in chick embryo, growth characteristics of the transplantation tumor, and the morphological characteristics and biological characteristics of the transplantation tumor. Results: The transplantation tumor model of human osteosarcoma in chick embryo was successfully established. It was found that the transplantation tumor was easy to grow and it showed strong angiogenesis-inducing effects. Under the light microscope, the transplantation tumor showed a similar tissue structure to human osteosarcoma. Conclusion: It is feasible to establish a transplantation tumor model of human osteosarcoma in chick embryo. The model can be easily duplicated with a simple operation, which provides a useful animal model for studying osteosarcoma. 展开更多
关键词 animal model chick embryo chorioallantoic membrane OSTEOSARCOMA
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Growth Modeling of Charolais and Serrana Soriana Native Spanish Beef Cattle
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作者 J. A. Miguel J. Ciria J. L. Calvo B. Asenjo 《Journal of Agricultural Science and Technology(A)》 2011年第5期778-782,共5页
The alternative productions, increasingly importance, are based on the rational utilization of the resources, on agreement with the environment and the use of autochthonous breeds that many cases are found in danger o... The alternative productions, increasingly importance, are based on the rational utilization of the resources, on agreement with the environment and the use of autochthonous breeds that many cases are found in danger of disappearance, due to the tact that their suckling is not economically profitable. A way of predicting and knowing the growth of the animals is using mathematical models. This work presented the results of the estimate of the growth according to the Gompertz-Laird model of males of the atttochthonous breed Serrana Soriana and Charolais. The weight to the birth of the breed calfs Charolais (45.14 kg), was superior to those of Serrana Soriana (40.13 kg), and presented a greater relative growth (9.9%) before the inflection point of the growth curve: furthermore it ~as also superior to the maximum decline relative after this point (6%), Serrana Soriana reached 7 days after the maximum growth point but with a smaller weight (315.05 kg vs 384.76 kg). It was calculated a weight to the maturity of 1 ,(176.91) kg for Charolais and 856.40 kg for Serrana Soriana. 展开更多
关键词 Alternative productions Gompertz-Laird growth curve beef cattle.
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Training gastroenterology fellows to perform gastric polypectomy using a novel ex vivo model
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作者 Ming-Jen Chen Ching-Chung Lin +6 位作者 Chia-Yuan Liu Chih-Jen Chen Chen-Wang Chang Ching-Wei Chang Chien-Wei Lee Shou-Chuan Shih Horng-Yuan Wang 《World Journal of Gastroenterology》 SCIE CAS CSCD 2011年第41期4619-4624,共6页
AIM:To evaluate the effect of hands-on training of gastroenterology fellows in gastric polypectomy using an ex vivo simulator.METHODS:Eight gastroenterology fellows at Mackay Memorial Hospital,Taipei were evaluated in... AIM:To evaluate the effect of hands-on training of gastroenterology fellows in gastric polypectomy using an ex vivo simulator.METHODS:Eight gastroenterology fellows at Mackay Memorial Hospital,Taipei were evaluated in gastricpolypectomy techniques using a pig stomach with artificial polyps created by a rubber band ligation device.The performance of four second year(year-2)fellows who had undergone one year of clinical training was compared with that of four f irst year(year-1)fellows both before and after a 4-h workshop using the ex vivo simulator.The workshop allowed for hands-on train-ing in the removal of multiple artif icial polyps and the placement of hemoclips at the excision site.Evaluation included observation of technical skills,procedure time,and the fellows' conf idence scale.RESULTS:One week after the workshop,the year-1 fellows were re-evaluated and had significantly im-proved mean performance scores(from 17.9 ± 1.8 to 22.5 ± 0.7),conf idence scale(from 4.5 ± 1.0 to 7.8 ± 0.5)and procedure time(from 615.0 ± 57.4 s to 357.5 ± 85.0 s)compared with their baseline performance.After 4 h of training using the ex vivo simulator,the skills of the year-1 fellows were statistically similar to those of the year-2 fellows.CONCLUSION:Use of this ex vivo simulator significantly improved the endoscopic gastric polypectomy skills of gastroenterology fellows who had not had previous clinical training in gastric polypectomy. 展开更多
关键词 Ex vivo Animal tissue model Hands-on training Pig stomach POLYPECTOMY
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Solitary gastric Peutz-Jeghers type stomach polyp mimicking a malignant gastric tumor
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作者 Jong-Shiaw Jin Ji-Kuen Yu +1 位作者 Tang-Yi Tsao Lien-Fu Lin 《World Journal of Gastroenterology》 SCIE CAS CSCD 2012年第15期1845-1848,共4页
Most cases of Peutz-Jeghers type polyps of the stomach are associated with mucocutaneous pigmentation and multiple intestinal polyposis.A solitary PeutzJeghers type polyp of the stomach is rare.We here report a case o... Most cases of Peutz-Jeghers type polyps of the stomach are associated with mucocutaneous pigmentation and multiple intestinal polyposis.A solitary PeutzJeghers type polyp of the stomach is rare.We here report a case of a 71-year-old woman with a solitary Peutz-Jeghers type polyp of the stomach who presented with intolerable epigastric pain and weight loss of 5 kg over the prior two months.During the hospital treatment course for this patient,endoscopic examination revealed a bulging lesion with a central hole,mucosal ulceration,an asymmetrical wall thickness and a narrowing of the gastric lumen.A gastric biopsy further revealed ulceration with moderate dysplasia.The patient received endoscopic ultrasonography which showed a second subepithelial lesion that measured 4 cm×3 cm.Computed tomography of the abdomen subsequently showed a thickened gastric wall with three visibly enlarged lymph nodes,all greater than 1 cm.The suspected diagnosis was malignant gastric cancer with lymph node metastases.The other lesion,which measured 2 cm×2 cm×1 cm was noted in the submucosa of the jejunum during surgery.The patient was treated using a subtotal gastrectomy and partial resection of the jejunal tumor.The final pathological report indicated a gastric Peutz-Jeghers type polyp with proliferation of smooth muscle bundles in the submucosal layer,and hyperplastic glands in the mucosal layer and ectopic pancreas of the jejunum.This is the first reported clinical case of a solitary Peutz-Jeghers type polyp of the stomach accompanying a lymph node enlargement and ectopic pancreas in the jejunum that simulates stomach cancer with lymph node metastases. 展开更多
关键词 Peutz-Jeghers type polyp Submucosa lesion Stomach cancer Ectopic pancreas Endoscopic ultrasonography
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A Survey on Pneumatic Muscle Actuators Modeling 被引量:1
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作者 Eleni Kelasidi George Andrikopoulos +1 位作者 George Nikolakopoulos Stamatis Manesis 《Journal of Energy and Power Engineering》 2012年第9期1442-1452,共11页
The aim of this article is to provide a survey on the most popular modeling approaches for PMAs (pneumatic muscle actuators). PMAs are highly non-linear pneumatic actuators where their elongation is proportional to ... The aim of this article is to provide a survey on the most popular modeling approaches for PMAs (pneumatic muscle actuators). PMAs are highly non-linear pneumatic actuators where their elongation is proportional to the interval pressure. During the last decade, there has been an increase in the industrial and scientific utilization of PMAs, due to their advantages such as high strength and small weight, while various types of PMAs with different technical characteristics have appeared in the literature. This article will: (a) analyse the PMA's operation from a mathematical modeling perspective; (b) present their merits and drawbacks of the most common PMAs; and (c) establish the fundamental basis for developing industrial applications and conducting research in this field. 展开更多
关键词 SURVEY MODELING PMA (pneumatic muscle actuator) pneumatic artificial muscle fluidic muscle.
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CFD modeling of a headbox with injecting dilution water in a central step diffusion tube
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作者 Xu Yang Jinsong Zeng +1 位作者 Kefu Chen Yucheng Feng 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2016年第10期1313-1324,共12页
For engineering applications of water dilution controlling system,the fluid dynamics of a mixed flow was studied with computational fluid dynamics(CFD) simulations and self-designed experimental set-up.In order to exa... For engineering applications of water dilution controlling system,the fluid dynamics of a mixed flow was studied with computational fluid dynamics(CFD) simulations and self-designed experimental set-up.In order to examine the predictability of CFD model for the headbox in industrial scale,two pulp suspensions before mixing were treated as homogeneous flows separately.Standard k-ε turbulence models with the mass diffusion in turbulent flows-species transport approach were applied in the simulations.A numerical simulation of this headbox model was analyzed with semi-implicit method for pressure linked equations scheme with pressure–velocity coupling.Results show that the model can predict hydrodynamic characteristics of headbox with injecting dilution water in a central diffusion tube,and the distribution of water content at the outlet of the slice lip is ideally normal at different speeds. 展开更多
关键词 Computational fluid dynamics Headbox Turbulence model Species transport Pulp suspension
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Dietary copper triggers onset of fulminant hepatitis in the Long-Evans cinnamon rat model 被引量:3
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作者 Ramsi Siaj Vanessa Sauer +4 位作者 Sandra Stppeler Hans-Ullrich Spiegel Gabriele Khler Andree Zibert Hartmut HJ Schmidt 《World Journal of Gastroenterology》 SCIE CAS CSCD 2012年第39期5542-5550,共9页
AIM: To investigate the impact of dietary copper given at different time points on the onset of fulminant hepatitis. METHODS: The Long-Evans cinnamon (LEC) rat mod- el of Wilson's disease (WD) was used to study... AIM: To investigate the impact of dietary copper given at different time points on the onset of fulminant hepatitis. METHODS: The Long-Evans cinnamon (LEC) rat mod- el of Wilson's disease (WD) was used to study the im- pact of high dietary copper (hCu) on the induction of fulminant hepatitis at early or late time points of life. High Cu diet was started in rat pups or in adults (month 5) for three months. Animals that received reduced di- etary copper (rCu) throughout their lifetime served as a control. Hepatitis-associated serum markers (alanine aminotransferase, aspartate transaminase, bilirubin) were analyzed in animal groups receiving hCu or rCu. Liver copper content and liver histology were revealed at sacrifice. A set of 5 marker genes previously found to be affected in injured liver and which are related to angiogenesis (Vegfa), fat metabolism (Srebf1), ex- tracellular matrix (Timp1), oxidative stress (Hmox1), and the cell cycle (Cdknla) were analyzed by real-time polymerase chain reaction. RESULTS: Regardless of the time point when hCu was started, LEC rats (35/36) developed fulminant hepati- tis and died. Animals receiving rCu (36/36) remained healthy, did not develop hepatitis, and survived long term without symptoms of overt disease, although liver copper accumulated in adult animals (477 ± 75 μg/g). With regard to start of hCu, onset of fulminant hepatitis was significantly (P 〈 0.001) earlier in adults (35±9 d) that showed pre-accumulation of liver copper as com- pared to the pup group (77±15 d). Hepatitis-associ- ated serum markers, liver copper and liver histology, as well as gene expression, were affected in LEC rats re- ceiving hCu. However, except for early and rapid onset of hepatitis, biochemical and molecular markers were similar at the early and late time points of disease. CONCLUSION: Rapid onset of fulminant hepatitis in asymptomatic LEC rats with elevated liver copper sug- gests that there is a critical threshold of liver copper which is important to trigger the course of WD. 展开更多
关键词 Wilson's disease Fulminant hepatitis Acuteliver failure Dietary copper Long-Evans cinnamon rat A TP7B
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Angle Control of a Pneumatically Driven Musculoskeletal Model Based on Coordination of Agonist-Antagonist Muscle
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作者 Yuki Honda Fumio Miyazaki Atsushi Nishikawa 《Journal of Mechanics Engineering and Automation》 2012年第12期709-719,共11页
In recent years, researchers have been actively pursuing research into developing robots that can be useful in many fields of industry (e.g., service, medical, and aging care). Such robots must be safe and flexible ... In recent years, researchers have been actively pursuing research into developing robots that can be useful in many fields of industry (e.g., service, medical, and aging care). Such robots must be safe and flexible so that they can coexist with people. Pneumatic actuators are useful for achieving this goal because they are lightweight units with natural compliance. Our research focuses on joint angle control for a pneumatically driven musculoskeletal model. In such a model, we use a one-degree-of-freedom joint model and a five-fingered robot hand as test beds. These models are driven by low pressure-driven pneumatic actuators, and mimic the mechanism of the human hand and musculoskeletal structure, which has an antagonistic muscle pair for each joint. We demonstrated a biologically inspired control method using the parameters antagonistic muscle ratio and antagonistic muscle activity. The concept of the method is based on coordination of an antagonistic muscle pair using these parameters. We have investigated the validity of the proposed method both theoretically and experimentally, developed a feedback control system, and conducted joint angle control by implementing the test beds. 展开更多
关键词 Musculoskeletal model pneumatic actuator position control muscle coordination agonist-antagonist muscle.
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Effects of the viability of Lactobacillus rhamnosus GG on rotavirus infection in neonatal rats 被引量:3
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作者 Hanna Ventola Liisa Lehtoranta +5 位作者 Mari Madetoja Marja-Leena Simonen-Tikka Leena Maunula Merja Roivainen Riitta Korpela Reetta Holma 《World Journal of Gastroenterology》 SCIE CAS CSCD 2012年第41期5925-5931,共7页
AIM:To study the effects of live and dead Lactobacillus rhamnosus GG(GG) on rotavirus infection in a neonatal rat model.METHODS:At the age of 2 d,suckling Lewis rat pups were supplemented with either live or dead GG a... AIM:To study the effects of live and dead Lactobacillus rhamnosus GG(GG) on rotavirus infection in a neonatal rat model.METHODS:At the age of 2 d,suckling Lewis rat pups were supplemented with either live or dead GG and the treatment was continued daily throughout the experi-ment.At the age of 5 and 6 d the pups received oral rotavirus(RV) SA-11 strain.The pups were sacrificed at the age of 7 or 8 d by decapitation.The gastrointestinal tract was removed and macroscopic observations were done.The consistency of feces in the colon was classified using a four-tier system.RV was detected from the plasma,small intestine,colon and feces by real-time quantitative polymerase chain reaction(PCR).RESULTS:In this neonatal rat model,RV induced a mild-to-moderate diarrhea in all except one pup of the RV-inoculated rats.RV moderately reduced body weight development from day 6 onwards.On day 7,after 2 d of RV infection,live and dead GG groups gained significantly more weight than the RV group without probiotics [36%(P = 0.001) and 28%(P = 0.031),respectively].In addition,when compared with the RV control group,both live and dead GG reduced the weight ratio of colon/animal body weight to the same level as in the healthy control group,with reductions of 22%(P = 0.002) and 28%(P < 0.001),respectively.Diarrhea increased moderately in both GG groups.However,the diarrhea incidence and severity in the GG groups were not statistically significantly different as compared with the RV control group.Moreover,observed diarrhea did not provoke weight loss or death.The RV control group had the largest amount of RV PCR-positive samples among the RV-infected groups,and the live GG group had the smallest amount.Rats receiving live GG had significantly less RV in the colon(P = 0.027) when compared with the RV control group.Live GG was also more effective over dead GG in reducing the quantity of RV from plasma(P = 0.047).CONCLUSION:Both live and dead GG have beneficial effects in RV infection.GG may increase RV clearance from the body and reduce colon swelling. 展开更多
关键词 DIARRHEA lactobacillus rhamnosus GG Neonatal rat ROTAVIRUS VIABILITY
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Expression Pattern of Peptide and Amino Acid Genes in Digestive Tract of Transporter Juvenile Turbot(Scophthalmus maximus L.) 被引量:3
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作者 XU Dandan HE Gen +3 位作者 MAI Kangsen ZHOU Huihui XU Wei SONG Fei 《Journal of Ocean University of China》 SCIE CAS 2016年第2期334-340,共7页
Turbot(Scophthalmus maximus L.),a carnivorous fish species with high dietary protein requirement,was chosen to examine the expression pattern of peptide and amino acid transporter genes along its digestive tract which... Turbot(Scophthalmus maximus L.),a carnivorous fish species with high dietary protein requirement,was chosen to examine the expression pattern of peptide and amino acid transporter genes along its digestive tract which was divided into six segments including stomach,pyloric caeca,rectum,and three equal parts of the remainder of the intestine.The results showed that the expression of two peptide and eleven amino acid transporters genes exhibited distinct patterns.Peptide transporter 1(Pep T1) was rich in proximal intestine while peptide transporter 2(PepT2) was abundant in distal intestine.A number of neutral and cationic amino acid transporters expressed richly in whole intestine including B^0-type amino acid transporter 1(B^0AT1),L-type amino acid transporter 2(LAT2),T-type amino acid transporter 1(TAT1),proton-coupled amino acid transporter 1(PAT1),y^+L-type amino acid transporter 1(y^+LAT1),and cationic amino acid transporter 2(CAT2) while ASC amino acid transporter 2(ASCT2),sodium-coupled neutral amino acid transporter 2(SNAT2),and y^+L-type amino acid transporter 2(y^+LAT2) abundantly expressed in stomach.In addition,system b^(0,+) transporters(rBAT and b^(0,+)AT) existed richly in distal intestine.These findings comprehensively characterized the distribution of solute carrier family proteins,which revealed the relative importance of peptide and amino acid absorption through luminal membrane.Our findings are helpful to understand the mechanism of the utilization of dietary protein in fish with a short digestive tract. 展开更多
关键词 TURBOT digestive tract amino acid PEPTIDE TRANSPORTER expression pattern
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Progression of diethylnitrosamine-induced hepatic carcinogenesis in carnitine-depleted rats 被引量:4
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作者 Salim S Al-Rejaie Abdulaziz M Aleisa +5 位作者 Abdulaziz A Al-Yahya Saleh A Bakheet Abdulmalik Alsheikh Amal G Fatani Othman A Al-Shabanah Mohamed M Sayed-Ahmed 《World Journal of Gastroenterology》 SCIE CAS CSCD 2009年第11期1373-1380,共8页
AIM:To investigate whether carnitine deficiency is a risk factor during the development of diethylnitrosamine (DENA)-induced hepatic carcinogenesis. METHODS:A total of 60 male Wistar albino rats were divided into six ... AIM:To investigate whether carnitine deficiency is a risk factor during the development of diethylnitrosamine (DENA)-induced hepatic carcinogenesis. METHODS:A total of 60 male Wistar albino rats were divided into six groups with 10 animals in each group.Rats in group 1(control group)received a single intraperitoneal(i.p.)injection of normal saline. Animals in group 2(carnitine-supplemented group) were given L-carnitine(200 mg/kg per day)in drinking water for 8 wk.Animals in group 3(carnitine-depleted group)were given D-carnitine(200 mg/kg per day)and mildronate(200 mg/kg per day)in drinking water for 8 wk.Rats in group 4(DENA group)were injected with a single dose of DENA(200 mg/kg,i.p.)and 2 wk later received a single dose of carbon tetrachloride(2 mL/kg) by gavage as 1:1 dilution in corn oil.Animals in group 5(DENA-carnitine depleted group)received the same treatment as group 3 and group 4.Rats in group 6 (DENA-carnitine supplemented group)received the same treatment as group 2 and group 4.RESULTS:Administration of DENA resulted in a significant increase in alanine transaminase(ALT), gamma-glutamyl transferase(G-GT),alkaline phosphatase(ALP),total bilirubin,thiobarbituric acid reactive substances(TBARS)and total nitrate/ nitrite(NOx)and a significant decrease in reduced glutathione(GSH),glutathione peroxidase(GSHPx), catalase(CAT)and total carnitine content in liver tissues.In the carnitine-depleted rat model,DENA induced a dramatic increase in serum ALT,G-GT,ALP and total bilirubin,as well as a progressive reduction in total carnitine content in liver tissues.Interestingly, L-carnitine supplementation resulted in a complete reversal of the increase in liver enzymes,TBARS and NOx,and a decrease in total carnitine,GSH,GSHPx, and CAT induced by DENA,compared with the control values.Histopathological examination of liver tissues confirmed the biochemical data,where L-carnitine prevented DENA-induced hepatic carcinogenesis while D-carnitine-mildronate aggravated DENA-induced hepatic damage. CONCLUSION:Data from this study suggest for the first time that:(1)carnitine deficiency is a risk factor and should be viewed as a mechanism in DENA- induced hepatic carcinogenesis;(2)oxidative stress plays an important role but is not the only cause of DENA-induced hepatic carcinogenesis;and(3) long-term L-carnitine supplementation prevents the development of DENA-induced liver cancer. 展开更多
关键词 Carnitine deficiency D-carnitine L-CARNITINE DIETHYLNITROSAMINE Hepatic carcinogenesis
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Prevalence and Predictors of Salmonella spp. in Retail Meat Shops in Kathmandu
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作者 Mukul Upadhyaya Naiyatat Poosaran Reinhard Fries 《Journal of Agricultural Science and Technology(A)》 2012年第9期1094-1106,共13页
A cross-sectional study was conducted from November 2008 to May 2009 to estimate the prevalence of Salmonella in retail meat shops in Kathmandu. The methods followed were ISO 18593:2004 for swab sample collection, IS... A cross-sectional study was conducted from November 2008 to May 2009 to estimate the prevalence of Salmonella in retail meat shops in Kathmandu. The methods followed were ISO 18593:2004 for swab sample collection, ISO 6579:2002 for Salmonella isolation and manufacturer's instructions (SIFIN, Germany) for serotype identification. A questionnaire was used to collect information on some of the risk factors of shops likely to be associated with Salmonella identification. A total of 492 environmental swab samples (164 chopping board samples, 164 knife samples and 164 table samples) from 82 retail meat shops were analyzed. The prevalence of Salmonella positive shops was 40.2% (95% CI: 29-51). The isolation rates of Salmonella from chopping boards (36.0%), knives (32.9%) and tables (25.0%) were not significantly different (P 〉 0.05). Retail meat shops were 1.9 times more likely to yield Salmonella in the evening (38.2%) as compared to the morning (24.4%) (P = 0.001). S. Typhimurium (54.5%) was the most common serotype found in retail meat shops followed by S. Enteritidis (16.9%), S. Haifa (13.6%), S. Virchow (10.4%), S. Agona (3.9%) and S. enterica (0.6%). Among the risk factors examined, "hygiene status of shop", "type of shops", "number of person handling meats", "number of knives used", "number of kinds of meat sold" and "number of kinds of meat sold using different numbers of knives" were individually significantly (P 〈 0.05) associated with Salmonella contamination in the retail meat shops. After univariate analysis of these risk factors, a final logistic regression model with Salmonella yes or no category of shops as outcome variable identified four significant predictors. Odds ratios, indicating the likelihood increase of a shop to achieve Salmonella positivity status were 10.17 for multiple persons rather than a single person involved, 7.66 for open rather than closed shops, 9.44 for use of several knives rather than one knife and 5.18 for single kind of meat using several knives. The results of this investigation revealed that retail meat shops to a noticeable extent are Salmonella contaminated, with a considerable degree of cross-contamination between meats and personnel and equipment used during a day in processing of meats. 展开更多
关键词 SALMONELLA retail meat shops PREVALENCE swab samples risk factors Kathmandu.
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A Prey- Predator Model for Venture Capital Investment
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作者 Letetia Mary Addison Balswaroop Bhatt David Owen 《Journal of Mathematics and System Science》 2017年第11期297-307,共11页
The Rosenzweig-Macarthur Model is used to partially explain Venture Capital investment cycles. Investment opportunities and the experience of the investors, represent the prey and predator respectively. Stability anal... The Rosenzweig-Macarthur Model is used to partially explain Venture Capital investment cycles. Investment opportunities and the experience of the investors, represent the prey and predator respectively. Stability analysis with respect to the interior equilibrium point is performed and dynamics of the system are investigated using numerical simulations and results are presented. The model shows that parameter variation affects the stability of the system and it experiences bifurcations. The results show that stability analysis is useful to provide a Venture Capitalist with the stability ranges of parameters in the system, to improve the quality of the investment process. 展开更多
关键词 prey- predator STABILITY Hopf bifurcations Venture Capital
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Facing different predators: adaptiveness of behavioral and morphological traits under predation 被引量:1
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作者 Martina HEYNEN Nils BUNNEFELD Jost BORCHERDING 《Current Zoology》 SCIE CAS CSCD 2017年第3期249-257,共9页
Predation is thought to be one of the main structuring forces in animal communities. However, se- lective predation is often measured on isolated traits in response to a single predatory species, but only rarely are s... Predation is thought to be one of the main structuring forces in animal communities. However, se- lective predation is often measured on isolated traits in response to a single predatory species, but only rarely are selective forces on several traits quantified or even compared between different predators naturally occurring in the same system. In the present study, we therefore measured be- havioral and morphological traits in young-of-the-year Eurasian perch Perca fluviatilis and com- pared their selective values in response to the 2 most common predators, adult perch and pike Esox lucius. Using mixed effects models and model averaging to analyze our data, we quantified and compared the selectivity of the 2 predators on the different morphological and behavioral traits. We found that selection on the behavioral traits was higher than on morphological traits and perch predators preyed overall more selectively than pike predators. Pike tended to positively se- lect shallow bodied and nonvigilant individuals (i.e. individuals not performing predator inspec- tion). In contrast, perch predators selected mainly for bolder juvenile perch (i.e. individuals spend- ing more time in the open, more active), which was most important. Our results are to the best of our knowledge the first that analyzed behavioral and morphological adaptations of juvenile perch facing 2 different predation strategies. We found that relative specific predation intensity for the di- vergent traits differed between the predators, providing some additional ideas why juvenile perch display such a high degree of phenotypic plasticity. 展开更多
关键词 behavior morphological variation Perca f/uviatilis PERCH PIKE predator-specific defenses selective predation
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Analysis of a harvested tritrophic food chain model in the presence of additional food for top predator 被引量:3
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作者 Prabir Panja Swarup Poria Shyamal Kumar Mondal 《International Journal of Biomathematics》 SCIE 2018年第4期271-299,共29页
In this paper, we propose and analyze a three-species predator prey system in the presence of additional food for top predator. It is assumed that the middle predator is acting as a prey as well as a predator and the ... In this paper, we propose and analyze a three-species predator prey system in the presence of additional food for top predator. It is assumed that the middle predator is acting as a prey as well as a predator and the top predator consumes both prey as well as middle predator. It is also considered that a constant amount of additional food for top predator exists in the ecosystem. The effects of harvesting of top predator are investigated. The existence and stability conditions of the equilibria have been discussed analytically. The Hopf bifurcation analysis of the system with respect to predation rate of prey to the top predator and the harvesting effort have been analyzed both analytically and numerically. Pontryagin's maximum principle is used to determine the optimal harvesting of top predator population to maximize the discounted net revenue. From our analysis, it is seen that the additional food has a significant impact to prevent the extinction risk of top predator population and also to increase revenue collection. Finally, some numerical results have been given in support of our analytical findings. 展开更多
关键词 PREDATOR PREY Hopf bifurcation Pontryagin's maximum principle Harvesting.
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