Comparison of the bond strength of ceramics to Co-Cr alloys made by casting and selective laser melting

Shirin Lawaf,Shahbaz Nasermostofi,Mahtasadat Afradeh,Arash Azizi 대한치과보철학회 2017 The Journal of Advanced Prosthodontics Vol.9 No.1

PURPOSE. Considering the importance of metal-ceramic bond, the present study aimed to compare the bond strength of ceramics to cobalt-chrome (Co-Cr) alloys made by casting and selective laser melting (SLM). MATERIALS AND METHODS. In this in-vitro experimental study, two sample groups were prepared, with one group comprising of 10 Co-Cr metal frameworks fabricated by SLM method and the other of 10 Co-Cr metal frameworks fabricated by lost wax cast method with the dimensions of 0.5 × 3 × 25 mm (following ISO standard 9693). Porcelain with the thickness of 1.1 mm was applied on a 3 × 8-mm central rectangular area of each sample. Afterwards, bond strengths of the samples were assessed with a Universal Testing Machine. Statistical analysis was performed with Kolmogorov-Smirnov test and T-test. RESULTS. Bond strength in the conventionally cast group equaled 74.94 ± 16.06 MPa, while in SLM group, it equaled 69.02 ± 5.77 MPa. The difference was not statistically significant (P ≤ .05). CONCLUSION. The results indicated that the bond strengths between ceramic and Co-Cr alloys made by casting and SLM methods were not statistically different.

Combination of Genistin and Fructooligosaccharides Prevents Bone Loss in Ovarian Hormone Deficiency

Shirin Hooshmand,Shanil Juma,Bahram H. Arjmandi 한국식품영양과학회 2010 Journal of medicinal food Vol.13 No.2

We have reported that soy isoflavones are capable of preventing loss of bone mineral density (BMD) in rats due to ovariectomy. The intestinal microflora is important in rendering soy isoflavones bioavailability by facilitating their conversion to equol. Hence, substances that can modulate the intestinal microflora could affect the bioavailability of isoflavones. The purpose of this study was to examine whether combination of genistin and fructooligosaccharides (FOS), a prebiotic, can enhance the effects of soy isoflavones on bone in ovariectomized (OVX) female rats. Forty-eight 90-day-old female Sprague-Dawley rats were either sham-operated (Sham; one group) or Ovx (three groups) and were placed on dietary treatment for 50 days. The Sham and one Ovx group received a control diet, and the remaining Ovx groups received genistin-rich isoflavones diet (Ovx+G) or genistin-rich isoflavones and FOS diet (Ovx+G+FOS). After 50 days, blood and bone specimens were collected for analysis. The genistin-rich isoflavones diet was able to significantly increase the whole-body, right femur, and fourth lumbar BMD by 1.6%, 1.48%, and 1.3%, respectively in comparison with the Ovx control. The combination of genistin-rich isoflavones diet and 5% FOS further increased whole-body, right femur, and fourth lumbar BMD more compared to the genistin-rich isoflavones diet. Our findings suggest that although a genistin-rich isoflavones diet can increase the BMD in rats with Ovx-induced bone loss, combination of genistin-rich isoflavones and FOS had greater effect in preventing bone loss in this rat model.

An unusual cause for trismus caused by mandibular coronoid osteoma : a case report

Shirin Vashishth,Kanika Garg,Venkatraman Sreenivasan 대한구강악안면방사선학회 2013 Imaging Science in Dentistry Vol.43 No.1

Osteoma is a dense bony proliferation of otherwise normal membranous bone. This tumor is essentially restricted to the craniofacial skeleton and is rarely diagnosed in other bones. The mandible and the paranasal sinuses are the most common sites, while the involvement of the coronoid process has been reported in only 6 cases so far. This report demonstrated a case of osteoma occurring at the mandibular coronoid process in a 26-year-old female patient. The patient was managed with surgical resection of the osteoma followed by physiotherapy.

Evaluation of Lipid Profile Changes in Pediatric Patients with Acute Mononucleosis

Shirin Sayyahfar,Amin Lavasani,Alireza Nateghian,Abdollah Karimi 대한감염학회 2017 Infection and Chemotherapy Vol.49 No.1

Background: Acute Epstein–Barr virus (EBV) infection could lead to atherogenic lipid profile changes in adults; while there is noevidence about the children with Infectious mononucleosis (IM). The aim of this study was to evaluate the lipid profile of the childrenin acute phase of mononucleosis and two months after the recovery. Materials and Methods: From 2010 through 2012, 36 children with IM aged 1-10 years were enrolled in a prospective cross-sectionalstudy. Fasting serum total cholesterol, high density lipoprotein (HDL), low density lipoprotein (LDL), and triglyceride levelwere measured during acute phase of the disease and after 2 months of the recovery. Results: From 36 patients enrolled, 25 (69.4%) cases were male and the mean age of the patients was 4.1 ± 2.0 years. The meanof the total cholesterol level in the acute phase and 2 months after the recovery were 149.5 ± 35.3 mg/dL and 145.7 ± 30.6,respectively (P = 0.38). However, the serum level of HDL cholesterol in patients after 2 months of recovery was significantly increased(37.9 ± 9.3 mg/dL vs. 28.5 ± 10.6 mg/dL, P <0.001). The mean value of serum LDL cholesterol was significantly reduced,two months after recovery (81.4 ± 19.5 mg/dL, vs. 92.6 ± 28.8 mg/dL, P = 0.009). Furthermore, the serum triglyceride level wassignificantly reduced after the recovery (108.7 ± 36.9 mg/dL) compared with the acute phase (163.8 ± 114.3 mg/dL) (P = 0.004). Conclusion: EBV infection in children could change lipid profile which is partially restored 2 months after the recovery.

Gram Scale and Room Temperature Functionalization of Boron Nitride Nanosheets for Water Treatment

Shirin Daneshnia,MOHSEN ADELI,Yaghoub Mansourpanah 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.8

Two-dimensional hexagonal boron nitride is a fascinating nanomaterial with a broad range of potential applications. However, further development of this nanomaterial is hampered because of its poor functionality and low processability. One of the efficient strategies for improving the processability of two-dimensional hexagonal boron nitride is the covalent functionalization of this nanomaterial. In this study, we report on a straightforward approach for functionalization of two-dimensional hexagonal boron nitride by lithium cyclopentadienyl and its application for water treatment. Cyclopentadienyl-functionalized boron nitride was characterized by different spectroscopy and microscopy methods as well as thermal and BET analysis. The synthesized nanomaterial was able to efficiently remove methylene blue from water in a short time. Adsorption capacity of this nanomaterial was as high as 476.3 mg/g, which was superior to the non-functionalized boron nitride. Our results showed that cyclopentadienyl-functionalized boron nitride is a promising candidate for the removal of cationic pollutants from water.

Antibiotic Susceptibility Evaluation of Group A Streptococcus Isolated from Children with Pharyngitis: A Study from Iran

Shirin Sayyahfar,Alireza Fahimzad,Amir Naddaf,Sara Tavassoli 대한감염학회 2015 Infection and Chemotherapy Vol.47 No.4

Background: The aim of this study was to evaluate the antibiotic susceptibility of Group A streptococcus (GAS) to antibiotics usually used in Iran for treatment of GAS pharyngitis in children. Materials and Methods: From 2011 to 2013, children 3-15 years of age with acute tonsillopharyngitis who attended Mofid Children’s Hospital clinics and emergency ward and did not meet the exclusion criteria were enrolled in a prospective study in a sequential manner. The isolates strains from throat culture were identified as GAS by colony morphology, gram staining, beta hemolysis on blood agar, sensitivity to bacitracin, a positive pyrrolidonyl aminopeptidase (PYR) test result, and the presence of Lancefield A antigen determined by agglutination test. Antimicrobial susceptibility was identified by both disk diffusion and broth dilution methods. Results: From 200 children enrolled in this study, 59 (30%) cases were culture positive for GAS. All isolates were sensitive to penicillin G. The prevalence of erythromycin, azithromycin, and clarithromycin resistance by broth dilution method was 33.9%, 57.6%, and 33.9%, respectively. Surprisingly, 8.4% of GAS strains were resistant to rifampin. In this study, 13.5% and 32.2% of the strains were resistant to clindamycin and ofloxacin, respectively. Conclusion: The high rate of resistance of GAS to some antibiotics in this study should warn physicians, especially in Iran, to use antibiotics restrictedly and logically to prevent the rising of resistance rates in future. It also seems that continuous local surveillance is necessary to achieve the best therapeutic option for GAS treatment.

ENERGENT: An Energy-Efficient UAV-Assisted Fog-IoT Framework for Disaster Management

Shirin Abkenar, Forough,Iranmanesh, Saeid,Bouguettaya, Athman,Raad, Raad,Jamalipour, Abbas 한국통신학회 2022 Journal of communications and networks Vol.24 No.6

In this paper, we propose ENergy-efficient disastERmanaGmENT (ENERGENT) as a novel framework for disastermanagement in the unmanned aerial vehicle (UAV)-assisted Fog-Internet of things (IoT) networks. ENERGENT optimizes theenergy consumption of the terminal nodes (TNs), as well asthe UAVs, using three proposed algorithms. The first algorithmoptimally adjusts the 3D placement of the UAVs such that thesenodes consume the minimum energy to reach the desired clusterof the TNs. Besides, the transmit power and the transmissionrate of the TNs are set in a way that their energy consumptionis minimized and the outage probability requirements are metin the network. In the second algorithm, we propose an optimaltask offloading scheme where tasks are offloaded to the UAVsin order to meet the network delay constraints. Finally, thethird algorithm takes advantage of wireless power transfer totransfer energy to the TNs when their remaining energy degradesa predefined threshold. This scheme guarantees a minimumthroughput for all TNs within a cluster by which the totalnetwork throughput is maximized. Simulation results revealthat ENERGENT outperforms the existing methods in terms ofoptimized network energy consumption, delay, and throughput.

Effect of GLUMA desensitizer on the retention of full metal crowns cemented with Rely X U200 self-adhesive cement.

Shirin Lawaf,Ezatallah Jalalian,Roshanak Roshan,Arash Azizi 대한치과보철학회 2016 The Journal of Advanced Prosthodontics Vol.8 No.5

PURPOSE. Considering the importance of retention in the success and long-term clinical service of fixed partial dentures (FPDs) as well as the existing controversy regarding the effect of GLUMA desensitizer on the retention of full metal crowns cemented with RelyX U200 self-adhesive cement, this study aimed to assess the effect of GLUMA desensitizer on the retention of full metal crowns cemented using RelyX U200. MATERIALS AND METHODS. In this experimental study, 20 sound human premolars were prepared; a 0.5 mm chamfer finish line was prepared above the cementoenamel junction. The teeth were randomly assigned to two groups: a desensitizer group (n = 10, treated with GLUMA desensitizer) and a control (n = 10, no surface treatment). Full metal crowns were fabricated of base metal alloy and had a ring. All crowns were cemented with RelyX U200 and subjected to retention test by using a universal testing machine. The data were analyzed using SPSS version 20 and independent t-test. RESULTS. The mean tensile bond strength was significantly higher in the GLUMA desensitizer group (230.63 ± 63.8 N) compared to the control group (164.45 ± 39.3 N) (P≤.012). CONCLUSION. GLUMA desensitizer increases the tensile bond strength of RelyX U200 self-adhesive cement to dentin.

Commercial tree products modeling case study in Gorazbon district, Kheyroud Forest, Iran

Shirin Varkouhi,Manoochehr Namiranian,Meghdad Joorgholami 한국산림과학회 2017 Forest Science And Technology Vol.13 No.2

Reliable yield predictions are essential for sustainable forest management, with the quality of forest management plans hinging on the reliability of growth and yield predictions. Due to lack of both efficient harvest plans and product models in Hyrcanian forests, these requirements have implications for model design, implementation, and use. This study aims to estimate the percentage of different industrial products for oriental beech (Fagus orientalis Lipsky) and hornbeam (Carpinus betulus L.) at the Kheyroud Forest Research Station located in the Caspian forests of northern Iran. For this purpose at first enhancement in accuracy of district’s tariff tables were done by new clues from a new inventory. In order to determine the relation between product percentages and diameter at breast height (DBH), a set of models extracted to help forest managers predict when, where, and how much timber of hornbeam and oriental beech in each diameter class can be harvested. The results showed logs to be the most important output, reaching a peak at 100 and 115 cm diameter classes in both species, versus Bolt grade 1 & 2 reaching a minimum in these diameter classes behave conversely due to decay and harrow stems. The result of validation showed high accuracy of models in predicting commercial tree species products. In general the model is considered suitable for implementation in integrated forest sector modeling.

The Impact of Mobile Technology on Vocabulary Learning of L2 Learners: The Case of WhatsApp Application

Shirin Tahounehchi 아시아테플 2021 The Journal of Asia TEFL Vol.18 No.1

Mobile technologies are receiving an increasing attention within diverse educational contexts. However, the scope of research on the affordances various mobile technologies provide to learning outcomes is still limited. The aim of this study was to investigate the effect of using WhatsApp application on vocabulary learning of Iranian EFL learners. Twenty-six female EFL learners at pre-intermediate level of proficiency were selected through convenience sampling to participate in the study. A vocabulary test was utilized for ensuring the homogeneity of the learners and then the participants were divided into two experimental (N = 13) and control (N = 13) groups, followed by assessing their vocabulary knowledge. Then, the 14-session treatment began, which included teaching new words using WhatsApp in the experimental group and traditional face-to-face method in the control group. At the end of the course, a vocabulary post–test was administered to both groups. Additionally, an attitude questionnaire was administrated to both groups for examining their attitude towards using WhatsApp and the traditional vocabulary learning method. The results indicated that the experimental group outperformed the control group. In addition, it was revealed that the learners who used WhatsApp for enhancing their vocabulary skill had a more positive attitude toward foreign language vocabulary learning as compared to the other group. The implications of the study for mobile-assisted vocabulary learning are discussed.