RISS 학술연구정보서비스

검색
다국어 입력

http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.

변환된 중국어를 복사하여 사용하시면 됩니다.

예시)
  • 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
  • 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
닫기
    인기검색어 순위 펼치기

    RISS 인기검색어

      검색결과 좁혀 보기

      선택해제
      • 좁혀본 항목 보기순서

        • 원문유무
        • 원문제공처
          펼치기
        • 등재정보
        • 학술지명
          펼치기
        • 주제분류
          펼치기
        • 발행연도
          펼치기
        • 작성언어
        • 저자
          펼치기

      오늘 본 자료

      • 오늘 본 자료가 없습니다.
      더보기
      • 무료
      • 기관 내 무료
      • 유료
      • A model for tensile strength of polymer/carbon nanotubes nanocomposites assuming the percolation of interphase regions

        Razavi, Razieh,Zare, Yasser,Rhee, Kyong Yop Elsevier 2018 Colloids and surfaces. A, Physicochemical and engi Vol.538 No.-

        <P><B>Abstract</B></P> <P>In this paper, a model is developed for tensile strength of polymer/carbon nanotubes nanocomposites (PCNT) assuming the network formation above percolation threshold based on Ouali approach. The reinforcing and networking roles of interphase are also considered in the developed model, because the interphase regions commonly form in polymer nanocomposites. Several equations are established to enable the developed model to predict the strength using the properties of polymer matrix, nanoparticles, and interphase. The suggested model is evaluated using the experimental results of several samples. Also, the logical and average levels of thickness, strength, and percolation threshold of interphase regions are calculated for the reported samples. The developed model shows acceptable agreement with the experimental results of nanocomposites. Additionally, the developed model demonstrates the reasonable effects of the volume fraction and radius of nanoparticles as well as the volume fraction, percolation threshold, thickness and strength of interphase on the strength. All observations validate the predictability of the developed model for tensile strength of PCNT.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

      • Accuracy of Endoscopic Ultrasonography for Determination of Tumor Invasion Depth in Gastric Cancer

        Razavi, Seyed Mohsen,Khodadost, Mahmoud,Sohrabi, Masoudreza,Keshavarzi, Azam,Zamani, Farhad,Rakhshani, Naser,Ameli, Mitra,Sadeghi, Reza,Hatami, Khadijeh,Ajdarkosh, Hossein,Golmahi, Zeynab,Ranjbaran, M Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.8

        Background: Gastric cancer (GC) is one the common lethal cancers in Iran. Detection of GC in the early stages would assesses to improve the survival of patients. In this study, we attempt to evaluate the accuracy of EUS in detection depth of invasion of GC among Iranian Patients. Materials and Methods: This study is a retrospective study of patients with pathologically confirmed GC. They underwent EUS before initiating the treatment. The accuracy of EUS and agreement between the two methods was evaluated by comparing pre treatment EUS finding with post operative histopathological results. Results: The overall accuracy of EUS for T and N staging was 67.9% and 75.47, respectively. Underestimation and overestimation was seen in 22 (14.2%) and 40 (25.6%) respectively. The EUS was more accurate in large tumors and the tumors located in the middle and lower parts of the stomach. The EUS was more sensitive in T3 staging. The values of weighted Kappa from the T and N staging were 0.53 and 0.66, respectively. Conclusions: EUS is a useful modality for evaluating the depth of invasion of GC. The accuracy of EUS was higher if the tumor was located in the lower parts of the stomach and the size of the tumor was more than 3 cm. Therefore, judgments made upon other criteria evaluated in this study need to be reconsidered.

      • Oral Cancer Knowledge and Practice among Dental Patients and their Attitude Towards Tobacco Cessation in Iran

        Razavi, Sayed Mohammad,Tahani, Bahareh,Nouri, Samin,Khazaei, Azadeh Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.13

        Background: One of the main causes of delay in diagnosis of oral cancer is lack of awareness about aetiology and symptoms among the general population. The aim of this study was to assess the knowledge and practice of patients regarding oral cancer and their attitude towards tobacco cessation. Materials and Methods: This study was carried out in Isfahan-Iran in 2014. A 29-item self-administrated questionnaire was designed and piloted and distributed to patients attending dental clinics. Questions were focused on awareness about oral cancer risk factors, signs and symptoms, places in the mouth which are more susceptible and attitude toward tobacco cessation. Chi-square, T-test, ANOVA and logistic regression tests were used for statistical analysis. Results: A total of 546 valid completed questionnaires were obtained. The mean knowledge score of patients was 4.1(${\pm}2.7$) out of 13. Some 80% of patients did not know about early manifestations of oral cancer. Only 18% knew the most likely sites of oral cancer. Only 43.1% and 65.2% of patients reported alcohol and tobacco consumption as the main risk factors but they had a fair knowledge about other risk factors. There was no significant difference in Knowledge level between patients regarding their sex, educational levels and age. Most patents (90%) expected their dentists to warn them about the harmful effects of smoking and showed willingness to quit if recommended. Conclusions: Knowledge about oral cancer was found to be quite low. It seems necessary to increase the level of public awareness using educational programs with cooperation of dentists in tobacco cessation programs.

      • Assessment of sensitivity-based FE model updating technique for damage detection in large space structures

        Razavi, Mojtaba,Hadidi, Ali Techno-Press 2020 Structural monitoring and maintenance Vol.7 No.3

        Civil structures may experience progressive deterioration and damage under environmental and operational conditions over their service life. Finite element (FE) model updating method is one of the most important approaches for damage identification in structures due to its capabilities in structural health monitoring. Although various damage detection approaches have been investigated on structures, there are limited studies on large-sized space structures. Thus, this paper aims to investigate the applicability and efficiency of sensitivity-based FE model updating framework for damage identification in large space structures from a distinct point of view. This framework facilitates modeling and model updating in large and geometric complicated space structures. Considering sensitivity-based FE model updating and vibration measurements, the discrepancy between acceleration response data in real damaged structure and hypothetical damaged structure have been minimized through adjusting the updating parameters. The feasibility and efficiency of the above-mentioned approach for damage identification has finally been demonstrated with two numerical examples: a flat double layer grid and a double layer diamatic dome. According to the results, this method can detect, localize, and quantify damages in large-scaled space structures very accurately which is robust to noisy data. Also, requiring a remarkably small number of iterations to converge, typically less than four, demonstrates the computational efficiency of this method.

      • Load-deflection analysis prediction of CFRP strengthened RC slab using RNN

        Razavi, S.V.,Jumaat, Mohad Zamin,El-Shafie, Ahmed H.,Ronagh, Hamid Reza Techno-Press 2015 Advances in concrete construction Vol.3 No.2

        In this paper, the load-deflection analysis of the Carbon Fiber Reinforced Polymer (CFRP) strengthened Reinforced Concrete (RC) slab using Recurrent Neural Network (RNN) is investigated. Six reinforced concrete slabs having dimension $1800{\times}400{\times}120mm$ with similar steel bar of 2T10 and strengthened using different length and width of CFRP were tested and compared with similar samples without CFRP. The experimental load-deflection results were normalized and then uploaded in MATLAB software. Loading, CFRP length and width were as neurons in input layer and mid-span deflection was as neuron in output layer. The network was generated using feed-forward network and a internal nonlinear condition space model to memorize the input data while training process. From 122 load-deflection data, 111 data utilized for network generation and 11 data for the network testing. The results of model on the testing stage showed that the generated RNN predicted the load-deflection analysis of the slabs in acceptable technique with a correlation of determination of 0.99. The ratio between predicted deflection by RNN and experimental output was in the range of 0.99 to 1.11.

      • SCOPUSKCI등재

        The Relaxant Activity of Safranal in Isolated Rat Aortas is Mediated Predominantly via an Endothelium-Independent Mechanism - Vasodilatory mechanism of safranal -

        Razavi, Bibi Marjan,Amanloo, Mojtaba Alipoor,Imenshahidi, Mohsen,Hosseinzadeh, Hossein KOREAN PHARMACOPUNCTURE INSTITUTE 2016 Journal of pharmacopuncture Vol.19 No.4

        Objectives: Safranal is a pharmacologically active component of saffron and is responsible for the unique aroma of saffron. The hypotensive effect of safranal has been shown in previous studies. This study evaluates the mechanism for the vasodilatory effects induced by safranal on isolated rat aortas. Methods: To study the vasodilatory effects of safranal (0.2, 0.4 and 0.8 mM), we contracted isolated rat thoracic aorta rings by using $10^{-6}-M$ phenylephrine (PE) or 80-mM KCl. Dimethyl sulfoxide (DMSO) was used as a control. The vasodilatory effect of safranal was also evaluated both on intact and denuded endothelium aortic rings. Furthermore, to study the role of nitric oxide and prostacyclin in the relaxation induced by safranal, we incubated the aortic rings by using L-NAME ($10^{-6}M$) or indomethacin ($10^{-5}M$), each for 20 minutes. Results: Safranal induced relaxation in endothelium-intact aortic rings precontracted by using PE or KCl in a concentration-dependent manner, with a maximum relaxation of more than 100%. The relaxant activity of safranal was not eliminated by incubating the aortic rings with L-NAME ($EC_{50}=0.29$ vs. $EC_{50}=0.43$) or with indomethacin ($EC_{50}=0.29$ vs. $EC_{50}=0.35$), where $EC_{50}$ is the half maximal effective concentration. Also, the vasodilatory activity of safranal was not modified by endothelial removal. Conclusion: This study indicated that relaxant activity of safranal is mediated predominantly through an endothelium-independent mechanism.

      • SCIESCOPUSKCI등재
      • Attitude and Practices Among Dentists and Senior Dental Students in Iran Toward Tobacco Cessation as an Effort to Prevent Oral Cancer

        Razavi, Sayed Mohammad,Zolfaghari, Behzad,Doost, Mostafa Emami,Tahani, Bahareh Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.1

        Background: Oral health professionals are responsible in Iran for providing a brief tobacco cessation program to smoker patients. The aim of this study was to assess Iranian dental student and dentist practice, knowledge and attitudes toward smoking cessation programs. Materials and Methods: A valid and reliable self-administered questionnaire was designed and distributed to 150 dentists working in Isfahan-Iran and 60 dental students. Some questions were developed based on the expected 5A tobacco cessation protocol. Statements on attitudes focused on professional responsibility towards smoking cessation and its effectiveness. Chi-square, ANOVA, and t test were used for statistical analysis. Results: The cessation program in dental settings covers a small group of patients (18%). Some 69.1% (n=96) of dentists reported asking their patients about tobacco use, 64% (n=83) advising their patients to quit, 33.8% (n=47) assessing their patients willingness to quit and 20% (n=28) reported helping their patients in changing their behavior. A far lower percentage reported active involvement in arranging assistance for smokers to quit (4.3%, n=5). Some 22% of students and 26% of dentists disagreed that the tobacco cessation programs should be as part of dentists' professional responsibility and 70% of them were willing to follow the protocol of tobacco cessation for patients. Conclusions: Iranian dentist performance regarding tobacco cessation is weak. Dentists and students indicated their lack of knowledge as the major reason for non-adherence to the protocol. Therefore, planning to encourage dentist to follow the protocol needs continuous educational programs.

      • SCIESCOPUS

        Laboratory investigation of the effects of translation on the near-ground tornado flow field

        Razavi, Alireza,Sarkar, Partha P. Techno-Press 2018 Wind and Structures, An International Journal (WAS Vol.26 No.3

        Translation of tornadoes is an important feature in replicating the near-ground tornado flow field which has been simulated in previous studies based on Ward-type tornado simulators using relative motion of the ground plane. In this laboratory investigation, effects of translation on the near-ground tornado flow field were studied using the ISU Tornado Simulator that can physically translate over a ground plane. Two translation speeds, 0.15 m/s and 0.50 m/s, that scale up to those corresponding to slowly-moving tornadoes in the field were selected for this study. Compared with the flow field of a stationary tornado, the simulated tornado with translation had an influence on the spatial distribution and magnitude of the horizontal velocities, early reversal of the radial inflow, and expansion of the core radius. Maximum horizontal velocities were observed to occur behind the center of the translating tornado and on the right side of its mean path. An increase in translation speed, resulted in reduction of maximum horizontal velocities at all heights. Comparison of the results with previous studies that used relative motion of the ground plane for simulating translating tornadoes, showed that translation has similar effects on the flow field at smaller radial distances (~2 core radius), but different effects at larger radial distances (~4 core radius). Further, it showed that the effect of translation on velocity profiles is noticeable at and above an elevation of ~0.6 core radius, unlike those in studies based on the relative motion of the ground plane.

      • KCI등재

        Biochemical characterization of digestive proteases and carbohydrases of the carob moth, Ectomyelois ceratoniae (Zeller) (Lepidoptera: Pyralidae)

        Parvin Razavi Tabatabaei,,Vahid Hosseininaveh,Seyed Hossein Goldansaz,Khalil Talebi 한국응용곤충학회 2011 Journal of Asia-Pacific Entomology Vol.14 No.2

        Digestive proteinases and carbohydrases of Ectomyelois ceratoniae (Zeller) larvae were investigated using appropriate substrates and inhibitors. Midgut pH in larvae was determined to be slightly alkaline. Midgut extracts showed optimum activity for proteolysis of hemoglobin at pH 9–12. Midgut proteinases also hydrolyzed the synthetic substrates of trypsin, chymotrypsin, and elastase at pH 8–11. Maximum digestive α-amylase activity was also observed at pH 8–11. However, optimum activity for α- and β-glucosidase occurred at pH 5–8. Alpha- and β-galactosidases optimum activities occurred at pH 5 and pH 6, respectively. Inhibitors of serine proteases were effective on midgut serine proteases (trypsin and chymotrypsin proteases). Zymogram analyses revealed at least five bands of total proteolytic activity in the larval midgut. Proteasespecific zymogram analyses revealed at least four, two, and one isozymes for trypsin-, chymotrypsin-, and elastase-like activities respectively. Two α-amylase isozymes were found in the midgut of fifth instar larvae and in the whole bodies of 1st through 5th instar larvae. Zymogram studies also revealed the presence of one and two bands of activity for β- and α-glucosidase, respectively. Recycling of α-amylase and proteases in the larval midgut was not complete. At least one isozyme of trypsin, chymotrypsin, elastase, and α-amylase were not recycled and were observed in the larval hindgut.

      연관 검색어 추천

      이 검색어로 많이 본 자료

      활용도 높은 자료

      해외이동버튼