10 research outputs found
Recorded Bedrock Motions and Site Effects Evaluation in Tehran City
In this paper, the results of theoretical analyses related to the evaluation of site effects in Tehran city, the capital of Iran, are presented. To evaluate the response of site, recorded bedrock motions in BHRC (Building and Housing Research Center) acceleration stations at Tehran city were used as bedrock input motion. These motions were recorded during Firozabad-Kojour (2004) earthquake (Ms=6.4), which occurred near Tehran city. Equivalent linear analysis was performed to evaluate the seismic response of each selected geotechnical and geophysical profile subjected to the scaled 475-year bedrock input motion. The results are presented in terms of site response spectrum and site amplification factor, computed in the period ranges 0.1- 0.5 and 0.1- 2.5 s. The estimated site response spectra were compared with the suggested one in Iranian Code (Standard No. 2800). This comparison reveals that there are acceptable trend between the estimated response spectra and Iranian Code. The values of amplification factor in ranges of period 0.1–0.5s and 0.1–2.5 s can also be considered in designing typical and generic buildings of the area
Determination of MSE Wall Pseudo Static Coefficient Based on Seismic Performance
This study, tries to suggest a design method based on displacement using finite difference numerical modeling in reinforcing soil retaining wall. In this case, loading characteristics, such as magnitude, frequency, peak ground acceleration and geometrical characteristics of reinforced soil structure are considered to correct the pseudo static method and finally introduce the pseudo static coefficient as a function of seismic performance level and peak ground acceleration. In addition, the authors has tried to simply suggest the equivalent harmonic loading of selected acceleration records. Considering the loading parameters, mechanically stabilized earth wall parameters and type of the site showed that the used method in this study leads to most efficient designs in comparison with other methods which are generally suggested in cods that are usually based on limitequilibrium concept. The outputs shows the over-estimation of equilibrium design methods in comparison with proposed displacement based methods here
Solvent-free preparation of amido-alkyl-phenols catalyzed by trityl chloride under neutral media
One-pot, multi-component condensation reaction of phenols, aromatic aldehydes, and amides in the presence of catalytic amount of trityl chloride (TrCl) as a homogeneous organocatalyst under solvent-free condition to prepare a new category of compounds, namely amido-alkyl-phenols has been reported. It is interesting that TrCl by in situ generation of trityl carbocation with inherent instability catalyzes the reaction.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author
Outcomes of Single Segment Implantation of Conventional Intacs versus Intacs SK for Keratoconus
Purpose: To compare the visual, refractive, and keratometric outcomes of single-segment conventional and severe keratoconus (SK) types of Intacs for correction of inferior keratoconus (KCN).
Methods: A total number of 41 consecutive eyes of 23 patients with a diagnosis of inferior KCN underwent Intacs implantation. Eight eyes were excluded due to postoperative complications (4 eyes) and loss to follow-up (4 eyes) and finally 33 eyes underwent statistical analysis. Two groups were created according to Intacs type insertion; conventional group (17 eyes) and SK groups (16 eyes). Intracorneal ring segments (ICRS) implantation was indicated in keratoconic patients with contact-lens intolerance or reduced best spectacle-corrected visual acuity (BSCVA).
Results: In the conventional group, mean uncorrected distance visual acuity (UCDVA) improved from 0.45 ± 0.41 preoperatively to 0.69 ± 0.39 six months after surgery representing a gain of 2 Snellen lines, and in the SK group mean UCDVA changed from 0.40 ± 0.35 preoperatively to 0.58 ± 0.48 equivalent to two Snellen lines improvement 6 months after operation (P = 0.48). Mean preoperative BSCVA in the conventional group improved from 0.72 ± 0.41 to 0.86 ± 0.39 (2 lines improvement) postoperatively and in the SK group improved from 0.71 ± 0.69 to 0.75 ± 0.45 (0.50 line improvement) ( P = 0.29). Mean preoperative spherical equivalent (SE) decreased from −4.86 ± 2.26 D to −3.57 ± 2.21 D (conventional group) and from −4.20 ± 1.82 D to −3.60 ± 1.89 D (P = 0.34), mean astigmatism (AST) decreased from −5.20 ± 2.07 D and −4.50 ± 2.26 D to −4.02 ± 2.57 D and − 3.18 ± 2.14 D in the conventional and SK groups, respectively (P = 0.68). Finally, mean K min decreased from 47.11 ± 2.51 D to 45.40 ± 3.30 D in the conventional group and from 45.05 ± 2.59 D to 44 ± 3.88 D in the SK group (P = 0.63) and mean K max was decreased from 52.82 ± 3.23 D to 50.52 ± 3.57 D and from 49.72 ± 3.17 D to 48.55 ± 4.50 D, respectively (P = 0.48).
Conclusion: Single-segment implantation of conventional and SK Intacs improved UCDVA and BSCVA, decreased corneal AST and keratometry in both groups with comparable outcomes
Effect of 830-nm diode laser irradiation on human sperm motility
Abstract Sperm motility is known as an effective parameter in male fertility, and it depends on energy consumption. Low-level laser irradiation could increase energy supply to the cell by producing adenosine triphosphate. The purpose of this study is to evaluate how the low-level laser irradiation affects the human sperm motility. Fresh human semen specimens of asthenospermic patients were divided into four equal portions and irradiated by 830-nm GaAlAs laser irradiation with varying doses as: 0 (control), 4, 6 and 10 J/cm 2 . At the times of 0, 30, 45 and 60 min following irradiation, sperm motilities are assessed by means of computer-aided sperm analysis in all samples. Two additional tests [HOS and sperm chromatin dispersion (SCD) tests] were also performed on the control and high irradiated groups as well. Sperm motility of the control groups significantly decreased after 30, 45 and 60 min of irradiation, while those of irradiated groups remained constant or slightly increased by passing of time. Significant increases have been observed in doses of 4 and 6 J/cm 2 at the times of 60 and 45 min, respectively. SCD test also revealed a non-significant difference. Our results showed that irradiating human sperms with low-level 830-nm diode laser can improve their progressive motility depending on both laser density and post-exposure time
Comparison of volatile/inhalational and IV anesthesia in long-term survival of patients with breast cancer: a retrospective study
Abstract Objective Breast cancer is a worldwide health concern, and surgical removal has remained the preferred therapeutic option in most patients. Furthermore, the current study was designed to investigate the disease-free survival and overall survival in breast cancer patients, who receive either propofol or isoflurane during operation. Method This retrospective study was conducted on 994 patients (IV group, n = 530; volatile/inhalational group, n = 464) who underwent breast cancer operation from January 2006 to December 2016 at Faghihi Hospital, Shiraz, Iran. All studied patients were followed up till 2020. Patients are classified into two groups, IV and volatile/inhalational, according to the received anesthesia. For statistical analysis, The Cox regression test was conducted to investigate the association between factors affecting the recurrence of the disease and the Log Rank test was utilized to assess the patients’ survival. Finally, to reduce the effect of confounding factors, all patients were matched according to age, tumor size and tumor grade. Results Based on results from the log-rank test, the volatile/inhalational group had a better recurrence-free survival (P = 0.039) compared to the total IV group. However, the overall survival was not considerably different (P = 0.520). Conclusion The current study showed that although 2-year disease-free survival is higher in the volatile/inhalational group, there is no meaningful association between the 5-year overall survival and anesthesia technique
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Laboratory evaluation of laparoscopic vascular clamps using a load-cell device--are all clamps the same?
The use of effective vascular clamps is key to successful laparoscopic partial nephrectomy. Based on our clinical experience the occlusive capabilities of vascular clamps appeared to be quite variable. We compared the occlusive force of currently available laparoscopic vascular clamps.
The jaw force of 3 laparoscopic vascular clamps (Aesculap(R), Klein Surgical Systems, San Antonio, Texas and Karl Storztrade mark) were measured by clamping a 2.2 mm compression load cell (Interface Advanced Force Measurement, Scottsdale, Arizona) in pound-force. The variables tested were handheld Satinsky, DeBakey and Storz clamps vs bulldog clamps, proximal, middle and distal application position, new vs used bulldog clamps and new vs used Satinsky handheld clamps. In addition, handheld clamps were tested according to the force generated by the notches in the locking mechanism. Force retention was also determined for all instruments after clamping a 20Fr latex rubber catheter for an hour. Finally, leak pressure studies were performed using a harvested porcine artery to determine the relationship between jaw force and leak pressure in mm Hg of bulldog and Satinsky handheld clamps using a pressure gauge (Cole-Parmer(R)).
Handheld vascular clamps provided greater force than bulldog clamps. The proximal position closest to the hinge provided the greatest force across all instruments. Compared to new clamps the 2-year-old Klein Surgical Systems bulldog clamps showed a greater than 40% decrease in jaw force at all positions, whereas the 3-year-old Aesculap bulldog clamps decreased in jaw force by less than 9% at all positions. The 2-year-old Satinsky handheld clamps showed a decrease of 20%, 9% and 0% at the distal, middle and proximal jaw positions, respectively. Also, there was a positive correlation between force and the number of notches applied in handheld clamps. In addition, all instruments maintained jaw force after 1 hour of continuous clamping. Finally, leak pressure studies performed with used clamps showed that Klein Surgical Systems bulldog, Aesculap bulldog and Satinsky handheld clamps leaked at a pressure of 153 to 223, 465 to 795 and 1,500 to 2,600 mm Hg, respectively.
Vascular clamps have varying occlusive forces according to clamp type, manufacturer, jaw and teeth characteristics, jaw clamping position and duration of use. However, across all clamps the jaw force was greatest at the proximal position. This is most important when applying laparoscopic bulldog clamps. In contrast, all handheld vascular clamps generated higher force than intracorporeal bulldog clamps. At 1 notch the handheld vascular clamps provided supraphysiological occlusion force regardless of position or manufacturer
International relations in the making of political Islam: interrogating Khomeini's ‘Islamic government’
Eurocentric approaches to political Islam tend to deploy an internalist methodology that theoretically obscures the generative and constitutive role of international relations. This article addresses this problem through a critical application of Leon Trotsky's idea of ‘uneven and combined development’ to Ayatollah Khomeini's invention of the concept of ‘Islamic government’. It argues that this concept was international in its socio-political stimulus and intellectual content, and, crucially, reflected, influenced, and mobilised an emergent liminal sociality that combined Western and Islamic socio-cultural forms. This heterogeneous character of Iran's experience of modernity is, the article argues, theoretically inaccessible to Eurocentric approaches’ homogeneous and unilinear conceptions of history, which, as a result, generate exceptionalist modes of explanations