273 research outputs found

    Role of histaminegic and calcium channels in the inhibitory effects of hydroalcoholic extract of matricaria recutita L. on isolated rabbit jejunum

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    Introduction: Considering the long traditional history of anti-inflammatory and anti-spasmodic effects of Matricria spices on the gastrointestinal system, the present study aimed to investigate the role of calcium channels and Histamine receptors in the inhibitory effects of hydroalcoholic dry extract of German chamomile (Matricaria recutita L.) on the isolated rabbit jejunum. Methods: All experiments were done on the isolated jejunum of New Zealand rabbits (1.8-2.5 kg). Dry extract of aerial parts of M. recutita was obtained by the maceration technique. The study was performed on two groups (n=6 in each group). In the first group, the effects of cumulative concentrations of M. recutita (3×10-3-1×10-2 mg/ml) on normal and K+-induced contractions (50 mM) of isolated jejunum were studied. In the second group, the inhibitory role of M. recutita (3 – 13×10-3 mg/ml) was evaluated in the presence and absence of histamine and cetrizine. In the presence and absence of 10 μM certizine, a histamine H1-antagonist, a concentration-dependent inhibitory effect of M. recutita extract in the range of 3-13×10-3 mg/ml was recorded the rabbit jejunum. Results: Results showed that EC50 of M. recutita in the absence and presence of K+ was 6.3×10-3 and 6.5×10- 3mg/ml, respectively. IC50 values for two concentrations of M. recutita (8×10-3 , 1×10-2 ) to abrogated contractive phase of Histamine was 9.55 × 10-6 and 1.57 × 10-6 μM. Cetrizine (10 μM) abolished inhibitory effects of M. recutita (IC50=3.6×10-3), (p< 0.001). Conclusion: Dry extract of matricaria recutita had inhibitory effects on the contractions of isolated rabbit jejunum. Calcium channels and histamine were involved in these antispasmodic effects

    A Generalized Modular Multilevel Current Source Inverter

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    This paper proposes a novel topology of multilevel current source inverter which is suitable to apply in low/medium voltage. The proposed topology is capable of producing desirable bidirectional output current levels. Furthermore, it can employ symmetrical DC current sources as well as asymmetrical ones which is a significant advantage. Asymmetrical mode makes it possible to generate a great number of output levels by appropriate selection of DC current source magnitude, needless to make changes in the hardware of the inverter. As a result, various methods are presented to compute the magnitude of needed DC current sources. In comparison to the conventional H-Bridge inverter (CHB), the proposed inverter has lessened the number of required DC current sources, switches as well as related gate driver circuits. The reduced number of required components has leads to cost and volume advantages. In addition, the control layout has become simpler. Reduction of power loss as a result of reduced number of on-state switches is the other merit of the proposed inverter. To evaluate the efficiency of the proposed inverter, its simulation and experimental results are extracted including results of various methods of determining DC current source magnitude

    Content analysis of secondary school chemistry textbooks based on components of resistance economy: Shannon Entropy Methodod

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    Background and Objectives:The present study aims to analyze the content of second grade chemistry textbooks based on the emphasis on the goals of resistance economy. Methods: The research method in this study was descriptive content analysis. In this study, after collecting quantitative data, Shannon entropy technique was used for anarysis. The statistical population of this study formed the content of all secondary high school chemistry textbooks. The sampling method in this study was census; Therefore, all second grade chemistry textbooks were analyzed. The registration unit in this study was the subject. In this study, the frequency of components and themes of resistance economy in chemistry curricula were examined. Findings: The findings of the content analysis showed that in secondary high school chemistry books, the most attention was paid to the goals of resistance economy in the field of consumption the field of skills and the field of production attitude. Conclusion: From the present study, it can be concluded that in the second grade chemistry textbooks, very little attention has been paid to the goals of the resistance economy. Also, in secondary school chemistry curricula, little attention has been paid to the goals and components of the resistance economy and the amount of attention to the goals of the resistance economy do not have a normal distribution and only some components of the resistance economy in the second secondary school (three dimensions and three areas) are consi dered

    Homotopy analysis method for solving multi-term linear and nonlinear diffusion–wave equations of fractional order

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    AbstractIn this paper we have used the homotopy analysis method (HAM) to obtain solutions of multi-term linear and nonlinear diffusion–wave equations of fractional order. The fractional derivative is described in the Caputo sense. Some illustrative examples have been presented

    Design of hierarchical structures for synchronized deformations

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    In this paper we propose a general method for creating a new type of hierarchical structures at any level in both 2D and 3D. A simple rule based on a rotate-and-mirror procedure is introduced to achieve multi-level hierarchies. These new hierarchical structures have remarkably few degrees of freedom compared to existing designs by other methods. More importantly, these structures exhibit synchronized motions during opening or closure, resulting in uniform and easily-controllable deformations. Furthermore, a simple analytical formula is found which can be used to avoid collision of units of the structure during the closing process. The novel design concept is verified by mathematical analyses, computational simulations and physical experiments

    Minor differences in body condition and immune status between avian influenza virus-infected and noninfected mallards: a sign of coevolution?

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    Wildlife pathogens can alter host fitness. Low pathogenic avian influenza virus (LPAIV) infection is thought to have negligible impacts on wild birds; however, effects of infection in free-living birds are largely unstudied. We investigated the extent to which LPAIV infection and shedding were associated with body condition and immune status in free-living mallards (Anas platyrhynchos), a partially migratory key LPAIV host species. We sampled mallards throughout the species\u27 annual autumn LPAIV infection peak, and we classified individuals according to age, sex, and migratory strategy (based on stable hydrogen isotope analysis) when analyzing data on body mass and five indices of immune status. Body mass was similar for LPAIV-infected and noninfected birds. The degree of virus shedding from the cloaca and oropharynx was not associated with body mass. LPAIV infection and shedding were not associated with natural antibody (NAbs) and complement titers (first lines of defense against infections), concentrations of the acute phase protein haptoglobin (Hp), ratios of heterophils to lymphocytes (H:L ratio), and avian influenza virus (AIV)-specific antibody concentrations. NAbs titers were higher in LPAIV-infected males and local (i.e., short distance) migrants than in infected females and distant (i.e., long distance) migrants. Hp concentrations were higher in LPAIV-infected juveniles and females compared to infected adults and males. NAbs, complement, and Hp levels were lower in LPAIV-infected mallards in early autumn. Our study demonstrates weak associations between infection with and shedding of LPAIV and the body condition and immune status of free-living mallards. These results may support the role of mallards as asymptomatic carriers of LPAIV and raise questions about possible coevolution between virus and host

    Knowledge, attitude and practice of nuclear medicine staff towards radiation protection

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    Introduction: Ionizing radiation in medical imaging is one of the dominant sources of exposure, and correct knowledge of radiation protection, affects staff safety behaviors during procedures. This study aimed to assess the radiation protection Knowledge, Attitude and Practice (KAP) amongst nuclear medicine centers' staff in Iran. Methods: To evaluate the level of radiation protection KAP, a validated questionnaire was distributed between 243 participants considering demographic characteristics in different geographical regions in Iran from 2014 to 2015. Results: There were statistically significant differences in the level of nuclear medicine staff KAP radiation protection with gender (p0.05). Conclusion: Our findings have shown that radiation protection KAP level of nuclear medicine staff was inadequate in some regions. This might be due to the lack of continuous training and absence of adequate safety knowledge about ionizing radiation. It seems that awareness about radiation protection rules and regulations, along with continuous training and preparations has a direct effect on radiation practice leading to enhanced KAP of staff in nuclear medicine centers. © 2019 Tehran University of Medical Sciences. All rights reserved

    Radiation protection knowledge, attitude, and practice (KAP) in interventional radiology

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    Objectives: Due to increasing cardiac disease and its mortality rate, the frequency of cardiac imaging has grown and, as a result, interventional cardiologists potentially receive high radiation doses in cardiac examinations. This study aimed to assess the knowledge, attitude, and practice (KAP) level of radiation protection (RP) among interventional radiology staff in Iranian health care centers across the country. Methods: We used a validated questionnaire survey consisting of 30 multiple-choice questions to perform a cross-sectional study. Participants were healthcare personnel working professionally with radiation at different levels (i.e., secretary, radiology technologists, nurse, and physician). The questionnaire was divided into three sections to assess KAP regarding RP. Results: Significant differences exist in RP KAP mean scores based on educational age (p 0.050). We found a significant difference between RP KAP mean scores and different regions (p < 0.050). Conclusions: Educational and practice age, sex, type of hospital, and geographical region affect he KAP of interventional radiology staff regarding RP. Since many of the subjective radiation harms for both medical team and patients, this can be easily controlled and prevented; a checkup for personnel of interventional radiology departments, considering samples from different parts of the country with different levels of education, continuous training, and practical courses may help map the status of KAP. The results of this study may also help authorized health physics officers design strategic plans to enhance the quality of such services in radiation departments. © 2018, Oman Medical Specialty Board. All rights reserved

    Assessment of knowledge, attitude and practice of operating room personnelss in selected hospitals of Iran about radiation protection

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    Introduction: Radiation protection in hospitals is a very important topic due to some economical, health, human and moral considerations. In order to promote a radiological protection program in hospitals, it is very important to have a good knowledge and attitude, as well as proper practice of personnels in this area. Therefore, the purpose of this study was to investigate the current status regarding knowledge, attitude and practice of operating room personnels about radiation protection in Iran. Materials and Methods: This descriptive cross-sectional study was performed on 332 operating room personnels with multi-stage selection in hospitals on the knowledge, attitude and practice at different cities in Iran. To do so, the operating room staff was considered as a statistical society during 2015-2016. The respondents to the questionnaire included physicists, nurses, apprentice and secretaries in different hospitals with low, medium and large number of beds. The selected provinces included: Alborz, East Azarbaijan, Tehran, Khorasan Razavi, Semnan, Qom, Golestan, Gilan, Kurdistan, Kermanshah and Mazandaran. Data were analyzed using SPSS software version 16 and one-way ANOVA test (P<0.05). Results: The findings of this study indicate that there is a significant relationship between the level of knowledge, attitude and practice of operating room personnels in radiation protection and different provinces. Also, the number of hospital beds is related whit the level of knowledge, attitude and performance of the personnels. Conclusion: The findings of current study showed that the provinces of Golestan, West Azarbayjan and Gilan had the highest level of knowledge, attitude and practice, respectively. Semnan, Tehran and Kurdistan were the provinces with the lowest level of knowledge, attitude and practice, respectively. There were also significant differences between the level of knowledge, attitude and practice of the personnel�s operating room with radiation protection and the place of service, which it can be due to the lack of supervision, facilities and lack of experience in deprived provinces, and oversight and inattention to the radiation exposure due to overcrowding of the services in non-deprived provinces. © 2018, Semnan University of Medical Sciences. All rights reserved
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