WORMHOLES IN SCALAR-TENSOR THEORIES OF GRAVITY

RIAZI N. The Korean Astronomical Society 1996 Journal of The Korean Astronomical Society Vol.29 No.suppl1

Wormhole solutions of general theory of relativity are known to violate energy conditions. We have considered the possibility of having wormhole solutions in Brans-Dicke theory which is the prototype of scalar-tensor theories of gravity.

Effect of Vitamin D on the Vaginal Health of Menopausal Women: A Systematic Review

Hedyeh Riazi,Masumeh Ghazanfarpour,Mahboubeh Taebi,Somayeh Abdolahian 대한폐경학회 2019 대한폐경학회지 Vol.25 No.3

Menopause is associated with the onset of climacteric symptoms due to low estradiol levels, which may cause insufficient maturation of the vaginal mucosa. Vitamin D may regulate the growth and differentiation of cells that are adversely affected due to low estradiol levels, thereby restoring vaginal health. The objective of this systematic review, the first on this subject, was to investigate the effect of vitamin D on the vaginal health of menopausal women. PubMed, Embase, Scopus, Web of Science, and Google Scholar databases and reference lists of hand-searched articles were searched for published studies from February 2000 to November 2018. The selection criteria were as follows: randomized or quasi-randomized trials that compared the effects of vitamin D or related compounds, alone or with calcium, on vaginal health (growth and differentiation of epithelial cells, dryness, acidity [pH]) outcomes in menopausal women. The methodological quality of these studies was examined using the Cochrane tool checklist by two independent investigators, following which the data were extracted. Of six examined studies, two showed that vitamin D administration improved the growth and differentiation of vaginal epithelial cells, improved vaginal pH, and decreased vaginal dryness in menopausal women. Although the level of evidence for the effects of vitamin D on vaginal health is low in our study, we concluded that vitamin D may improve the vaginal health of women, especially during menopause.

Performance of polyacrylamide/Cr(III) gel polymer in oil recovery from heterogeneous porous media: An experimental study

Masoud Riazi,Zahra Kargozarfard,Shahab Ayatollahi,Sheida Shahnazar 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.12

Water channeling due to reservoir heterogeneity is an important factor that could decrease the displacement efficiency of a water flooding process. In this study, the ability of polyacrylamide/ chromium acetate system on altering water path in heterogeneous layered media was investigated using glass bead micromodels. After the relevant parameters were optimized, a series of water and gel injection experiments were conducted in glass bead micromodel. The experimental results show that sweep efficiency is basically controlled by gel strength. The gel strength has a minor impact on the oil recovery from the higher permeable zone, whereas the oil recovery from the lower permeable zone is a strong function of gel strength. Gels with F and G strength codes were observed to divert the water path mostly into low permeable layers. Whereas, gels with B strength code or weaker would alter the water path within the higher permeable layers.

Iranian EFL Learners' Pattern of Language Learning Strategy Use

Abdolmehdi Riazi,Mohammad Rahimi 아시아영어교육학회 2005 The Journal of Asia TEFL Vol.2 No.1

Lexis in English Textbooks in Iran: Analysis of Exercises and Proposals for Consciousness-Raising Activities

( Abdolmehdi Riazi ),( Arezoo Aryashokouh ) 범태평양응용언어학회 2007 범태평양응용언어학회지 Vol.11 No.1

Influence of Ultraviolet Light Irradiation on the Corrosion Behavior of Carbon Steel AISI 1015

H. R. Riazi,I. Danaee,M. Peykari 대한금속·재료학회 2013 METALS AND MATERIALS International Vol.19 No.2

Corrosion of carbon steel in sodium chloride solution was studied under ultraviolet illumination using weight loss, polarization, electrochemical impedance spectroscopy and current transient tests. The polarization test revealed an increase in the corrosion current density observed under UV illumination. The impedance spectroscopy indicated that the charge transfer resistance of the system was decreased by irradiation of UV light on a carbon steel electrode. The weight loss of carbon steel in solution increased under UV light,which confirms the results obtained from electrochemical measurements. We propose that the main effect of UV irradiation is on the oxide film, which forms on the surface. Thus, in presence of UV, the conductivity of oxide film might increase and lead to higher metal dissolution and corrosion rate.

Incidence of Venous Thromboembolic Complications in Instrumental Spinal Surgeries with Preoperative Chemoprophylaxis

Hamidi, Saeed,Riazi, Mahdieh The Korean Neurosurgical Society 2015 Journal of Korean neurosurgical society Vol.57 No.2

Objective : Venous thromboembolism (VTE) after spinal surgery affects a patients' postoperative recovery and also carries a mortality risk. Some studies recommended chemical prophylaxis for high-risk patients and for those after complex spinal surgeries. However, chemoprophylaxis for VTE in spinal surgery is underemployed and there is no agreement on the use of VTE prophylaxis in spinal surgery. The aim of this study was to document the incidence of VTE after an elective instrumental spinal surgery, among those receiving preoperative chemoprophylaxis as compared with patients who did not receive it. Methods : This study was carried out on eighty-nine patients allocated randomly to receive either low molecular weight heparin (LMWH) or no prophylaxis before elective instrumental spinal surgery. All patients received postoperative compression stockings. A compression Doppler ultrasonography was performed for all patients to detect postoperative deep vein thrombosis. In addition, further imaging studies were performed for patients suspected of VTE. Results : Three (3.3%) patients were diagnosed with VTE. One of them had received preoperative chemoprophylaxis. There were no significant difference in incidence of VTE between the two groups (p>0.95; 95% confidence interval, 0.06-8.7). Laterality of gender and postsurgical recumbence duration were all independent predictors of VTE (p=0.01 and p<0.001, respectively). Conclusion : The difference in the incidence of thromboembolic complications between the two groups was not significant. Moreover, we found that preoperative prophylactic LMWH injection has no major bleeding complications altering postoperative course; still, the issue concerning the initiation time of chemoprophylaxis in spinal surgery remains unclear.

Cutoff Values of Plasma D-Dimer Level in Patients with Diagnosis of the Venous Thromboembolism after Elective Spinal Surgery

Saeed Hamidi,Mahdieh Riazi 대한척추외과학회 2015 Asian Spine Journal Vol.9 No.2

Study Design: A prospective clinical study. Purpose: Our objective in the present study was twofold. First, we sought to evaluate the relationship between postoperative venous thromboembolism (VTE) development and concentration of D-dimer to determine the cutoff value in patients who underwent elective spinal surgery. Second, we identified the predictive risk factors for postoperative VTE. Overview of Literature: VTE affects the general health of patients and may even cause death. Since the complications of VTE are difficult to predict, the safest and most cost effective diagnostic method should be used in order to confirm a suspected VTE event after spinal surgery. Methods: This study was performed on 97 patients who underwent elective spinal surgery. The D-dimer assay was carried out on the day before surgery, and on days 1, 3, and 10 following surgery. VTE occurrence and D-dimer levels were compared between the VTE and the control groups. Results: Four patients (4.1%) were diagnosed with deep vein thrombosis and one patient (1%) was diagnosed with a pulmonary embolism. The optimum D-dimer cutoff value on day 3 following surgery in the VTE group was determined to be more than 2.1 μg/mL with a sensitivity of 100% and a specificity of 80.7%. Moreover, the duration of postoperative recumbency was a significant risk factor for the development of VTE in this study. Conclusions: We have demonstrated that postoperative D-dimer measurements in patients who underwent elective spinal surgery can provide a complementary diagnostic screening for VTE during the first week after surgery.

MHD copper-water nanofluid flow and heat transfer through convergent-divergent channel

Mohammadreza Azimi,Rouzbeh Riazi 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.10

This work is focused on the analytical solution of a nanofluid consisting of pure water with copper nanoparticle steady flow through convergent-divergent channel. The velocity and temperature distributions are determined by a novel method called Reconstruction of variational iteration method (RVIM). The effects of angle of the channel, Reynolds and Hartmann numbers on the nanofluid flow are then investigated. The influences of solid volume fraction and Eckert number upon the temperature distribution are discussed. Based on the achieved results, Nusselt number enhances with increment of solid volume fraction of nanoparticles, Reynolds and Eckert numbers. Also the fourth order Runge-Kutta method, which is one of the most relevant numerical techniques, is used to investigate the validity and accuracy of RVIM and good agreement is observed between the solutions obtained from RVIM and some known numerical results.

Modification of Substrate Inhibition of Synaptosomal Acetylcholinesterase by Cardiotoxins

Ranaei-Siadat, Seyed-Omid,Riazi, Gholam-Hosein,Sadeghi, Mehdi,Chang, Long-Sen,Lin, Shinne-Ren,Eghtesadi-Araghi, Peyman,Hakimelahi, Gholam Hossein,Moosavi-Movahedi, Ali Akbar Korean Society for Biochemistry and Molecular Biol 2004 Journal of biochemistry and molecular biology Vol.37 No.3

Different types of cardiotoxin (I-V and n) were isolated and purified from the venom of the Taiwan cobra (Naja naja atra). The effects of these cardiotoxins were studied on membrane-bound acetylcholinesterase, which was isolated from a sheep's brain cortex. The results showed that cardiotoxins I-III, V, and n activated the enzyme by modification of substrate inhibition, but cardiotoxin IV's reaction was different. The inhibition and activation of acetylcholinesterase were linked to the functions of the hydrophobicity index, presence of a cationic cluster, and the accessible arginine residue. Our results indicate that Cardiotoxins have neither a cationic cluster nor an arginine residue in their surface area of loop I; therefore, in contrast to fasciculin, cardiotoxins are attached by loop II to the peripheral site of the enzyme. As a result, fasciculin seems to stabilize nonfunctional conformation, but cardiotoxins seem to stabilize the functional conformation of the enzyme. Based on our experimental and theoretical findings, similar secondary and tertiary structures of cardiotoxins and fasciculin seem to have an opposite function once they interact with acetylcholinesterase.