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| 1 | Inoperable esophageal cancer and outcome of palliative care显示文摘AIM:To determine the outcome of esophageal cancer patients referred for palliative care,in Gorgan and Gonbad gastrointestinal clinics,northeast of Iran. METHODS:This cross-sectional study was done on inoperable esophageal cancer cases referred to gastrointestinal clinics in Gorgan and Gonbad city(2005-2006) . Demographic data were collected during the procedure and cases were followed up every one month. Improvement proportion was calculated with 95% confidence interval,to determine the rate of improvement. Survival analysis and Kaplan-Meier methods were used to estimate the duration of palliative care effectiveness. RESULTS:We recruited 39 cases into the study. Squamous cell carcinoma was the most prevalent(92.3%) . The middle third of the esophagus was involved predominantly(51.3%) . Dilation was the most preferred method(89.7%) and stenting was done in 4 cases. Decreasing dysphagia score was not related to palliation method or pathology type of carcinoma. Age of the patients was significantly related to the improvement of dysphagia score. Mean survival time was 137.6 d and median was 103 d. CONCLUSION:Results of this study showed a low survival rate after palliative care in esophageal cancer cases despite dysphagia scores' improvement after dilating or stenting. | Sima Besharat Ali Jabbari Shahryar Semnani Abbasali Keshtkar Jeran Marjani | 2008 | World Journal of Gastroenterology2008，14，23： | 5 |
| 2 | Numerical approach for enhanced oil recovery with surfactant flooding显示文摘The remained oil in the reservoir after conventional water-flooding processes,forms a dispersed phase in the form of oil drops which is trapped by capillary forces and is almost about 70%of the original oil in the place(OOIP).To reduce oil residual saturation in laboratory experiments and field projects,surfactant flooding is effective via decreasing the interfacial tension mobility ratio between oil and water phases.Estimation of the role of design variables,like chemical concentrations,partition coefficient and injection rate in different performance quantities,considering a heterogeneous and multiphase oil reservoir is a critical stage for optimal design.Increasing demand for oil production from water-flooded reservoirs has caused an increasing interest in surfactant-polymer(SP)and alkali-surfactant-polymer(ASP).Modeling minimizes the risk of high cost of chemicals by improving our insight of process.In the present paper,a surfactant compositional flood model for a three-component(water,petroleum and surfactant),two phase(aqueous and oleic)system is studied.A homogeneous,two-dimensional,isothermal reservoir with no free gas or alkali is assumed.The governing equations are in three categories:the continuity equations for the transport of each component,Darcy's equation for the transport of each phase and other auxiliary equations.The equations are solved by finite-differences using a procedure implicit in pressure and explicit in saturation.The validation of the model is achieved through comparing the modeling results with CMG simulators and BuckleyeLeverett theory.The results of modeling showed good agreement with CMG results,and the comparison with BuckleyeLeverett theory is explained according to different assumptions.After validation of the model,in order to investigate sensitivity analysis,the effects of system variables(partition coefficient,surface tension,oil viscosity and surface injection concentration)and performance variable(cumulative oil recovery)are studied.Finally,the comparison of oil recovery between water-flooding and surfactant-flooding was done.The results showed higher oil recovery with changes in capillary number when the partition coefficient is greater than unity.Increasing oil viscosity resulted in decreasing the oil recovery by changing in fractional flow.Moreover,it was concluded that the oil recovery was enhanced by increasing surfactant injection concentration.The oil recovery was increased when surfactant was injected to the system and this result was obtained by comparing water-flooding and surfactantflooding. | Sadegh Keshtkar Morteza Sabeti Amir H.Mohammadi | 2016 | Petroleum2016，2，1： | 4 |
| 3 | 问荆提取物页岩水化膨胀抑制剂性能及防膨机理显示文摘提出将问荆提取物作为页岩水化膨胀抑制剂,通过室内实验研究了其抑制页岩水化膨胀的性能,与氯化钾和聚胺进行了对比,并分析了其防膨机理。膨润土水化抑制实验、膨润土沉淀实验、动态线性膨胀实验、滚动回收实验和吸附量测定实验结果表明:问荆提取物可以抑制膨润土的水化,阻止黏土矿物在溶液中均匀分散,减小膨润土的膨胀,抑制钻屑在水中破碎和分散,且与氯化钾和聚胺性能相当。对问荆提取物的防膨机理进行分析后发现:其成分中具有活性烃基的物质与膨润土颗粒表面间氢键缔合,降低了膨润土颗粒表面的吸水率,从而抑制膨润土膨胀。除了具有良好的防膨能力,问荆提取物获取容易、价格低廉,且不会破坏生态环境,是一种理想的页岩水化膨胀抑制剂。 | BARATI Pezhman KESHTKAR Sadegh AGHAJAFARI Amirhossein SHAHBAZI Khalil MOMENI Ali | 2016 | 石油勘探与开发2016，43，3： | 4 |
| 4 | Knowledge management and the entrepreneur:Insights from Ikujiro Nonaka's Dynamic Knowledge Creation model(SECI)显示文摘A key goal of knowledge management(KM)is to foster innovation through the ceation of new knowledge.Surprisingly,there is little research on KM in the context of entrepre-neurship,a domain where innovation is considered essential.This paper extends estab-lished theories and frameworks for KM to the understudied context of KM in small and medium entrepreneurial firms,particularly young startups.Translating KM fr ameworks,such as the widely studied SECI model,into the entrepreneurial domain could eventually help startups in their quest for sustainability and growth.The SECI model is an aspir ational process with which to build new knowledge,including the explicit knowledge assets that startups commonly lack.However,an aspiration is only useful if the subject knows where he or she stands in relation to it.This study focuses on understanding whether entre-preneurial activities embed into,and can further enable,the'virtuous'knowledge-creation cycle.The secondary objective of this paper is to acknowledge Ikujiro Nonaka's contribution to western and eastern KM theories,and extend his seminal theories into other domains,such as small and medium enterprises.This work pilots the use of a content analysis technique largely used in psychology to analyze the connection between entrepreneurship and KM.With this method,the study highlights how the four phases of the SECI model apply to startup firms in a business incubator in the United States.It provides insights into the knowledge-creation process of entrepreneurs,and suggests how entrepreneurs can improve startup survival through greater awareness and use of KM in their business planning and operational activities. | Cesar Bandera Fazel Keshtkar Michael R.Bartolacci Shiromani Neerudu Katia Passerini | 2017 | International Journal of Innovation Studies2017，1，3： | 4 |
| 5 | Preparation of Rod-like Aluminum Doped Zinc Oxide Powders by Sol-gel Technique Using Metal Chlorides and Acetylacetone Precursors显示文摘Al-doped ZnO(AZO) powders were prepared by using metal chloride precursors and the sol-gel technique. IR peaks observed at 1590 cm-1 and 1620 cm^(-1) indicated the formation of metal chelate as a consequence of the addition of acetylacetone to the metal chloride solution. TG-DSC analysis of the AZO gels confirmed the formation of metal chelate as evidenced by the development of several weight loss peaks accompanied by the introduction of new endothermic peaks. The resulting AZO gels were annealed at 500, 600, and 800 ℃ to study the effect of annealing temperature. XRD and SEM results showed that crystallization of AZO gels takes place around 600 ℃. Hexagonal wurtzite structure was identified as the main phase for all the samples. In addition, small shift of the XRD(002) peak coupled with XPS results from the AZO powders confirmed the successful doping of the ZnO powders. Micron sized rod-like AZO powders were uniform in dimension and morphology and remained stable even at 800 ℃. | KESHTKAR Javad VARGAS GARCIA Jorge Roberto GALAVIZ PEREZ Jorge MARTINEZ TRINIDAD José | 2018 | Journal of Wuhan University of Technology(Materials Science)2018，33，6： | 2 |
| 6 | The effect of bladder volume changes on the measured electrical impedance of the urothelium显示文摘 | Ahmad Keshtkar Asghar Mesbahi Parinaz Mehnati | 2008 | International Journal of Biomedical Engineering and Technology2008，1，3： | 1 |
| 7 | Comparative study on PVA/silica membrane functionalized with mercapto and amine groups for adsorption of Cu(II) from aqueous solutions显示文摘 | Mohammad Irani Ali Reza Keshtkar Mohammad Ali Moosavian | 2012 | Journal of the Taiwan Institute of Chemical Engineers2012，，： | 1 |
| 8 | The effect of applied pressure on the electrical impedance of the bladder tissue using small and large probes显示文摘 | Keshtkar A | 2008 | J Med Eng Technol2008，32，6： | 1 |
| 9 | Equilibrium, kinetic and thermodynamic study of the biusorption of uranium onto Cystoseria indica algae显示文摘 | Khani M H Keshtkar A R Ghannadi M | 2008 | Journal of Hazardous Materials2008，150，： | 1 |
| 10 | Durability design process for truck body structures显示文摘 | Sridhar Srikantan Shekar Yerrapalli Hamid Keshtkar | 2000 | International Journal of Vehicle Design2000，23，95： | 1 |
| 11 | Transition study of current dis- tribution and maximum current density in railgun by 3-D FEM-IEM 显示文摘 | Bayati M S Keshtkar A | 2011 | IEEE Transactions on Plasma Science2011，39，1： | 1 |
| 12 | Bladder eaneer detection usingeleetrieal impedance technique ( tabfiz mark 1 ) 显示文摘 | Keshtkar A Salehnia Z Keshtkar A | 2012 | Patholog Res Int2012，，47： | 1 |
| 13 | Relationship between p53 expression and gastric cancers in cardia and antrum 显示文摘 | Azarhoush R Keshtkar AA Amiriani T | 2008 | Arch Iran Med2008，1，5： | 1 |
| 14 | The role of IL-6 for predicting neonatal sepsis:a systematic review and meta-analysis显示文摘 | Shahkar L Keshtkar A Mirfazeli A | 2011 | Iran J Pediatr2011，21，4： | 1 |
| 15 | Equilibrium, kinetic and thermodynamic study of the biosorption of uranium onto cysto- seria indica algae显示文摘 | KHANI M H KESHTKAR A R GHANNADI M | 2008 | Journal of Hazardous Materials2008，150，： | 1 |
| 16 | Development and extension of PSRK/UNIQUAC model to methane and ni- trogen gases 显示文摘 | Keshtkar A Jalali F Moshfeghian M | 1998 | Fluid Phase Equilibia1998，145，： | 1 |
| 17 | Some early results related to electrical impedance of normal and abnormal gastric tissue 显示文摘 | Keshtkar A Salehnia Z Somi MH | 2012 | Phys Med2012，28，1： | 1 |
| 18 | The role of IL- 6 for predicting neonatal sepsis:a systematic review and meta-analysis显示文摘 | Shahkar L Keshtkar A Mirfazeli A | 2011 | Iran J Pediatr2011，21，4： | 1 |
| 19 | Effect of rail dimension on current distribution and inductance gradient显示文摘 | Keshtkar A | 2005 | IEEE Transactions on Magnetics2005，41，1： | 1 |
| 20 | Transition study ofcurrent distribution and maximum current density in railgun by 3-D FEM-IEM显示文摘 | BAYATI M S KESHTKAR A | | 0，，01： | 1 |
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