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Background: Staphylococcus epidermidis isolates are among the most important causes of nosocomial infections and could be classified as health threatening agents. This study aimed to determine the biofilm formation ability and clonal dissemination of S. epidermidis strains isolated from patients and healthy people in Isfahan during 2016 and 2017.
Materials & Methods: A total of 139 and 123 suspected colonies of S. epidermidis were collected from different clinical specimens and the arm of healthy people, respectively. The ability to form biofilm was determined using a combination of Congo-red agar (CRA) and microtiter plate (MTP) assays. The presence of genes involved in biofilm formation was also tested by the polymerase chain reaction (PCR) test. The susceptibility of all strains to 12 antibiotics was evaluated using the disk diffusion method according to the Clinical & Laboratory Standards Institute (CLSI) guidelines. Moreover, all biofilm-producing strains were typed using PhenePlate system as well as cassette chromosome mec (SCCmec) and accessory gene regulator (agr) locus typing method.
Findings: A total of 43 biofilm-producing S. epidermidis strains were identified among 107 and 123 confirmed strains isolated from hospitalized patients and healthy people, respectively; all of which were positive for aap gene, and the presence of ica operon was limited to 86 and 27% of the strains isolated from patients and healthy people, respectively. All the strains showed susceptibility to vancomycin, quinupristin-dalfopristin, and linezolid. Moreover, SCCmec Types III, IV, and V were detected among all methicillin-resistant S. epidermidis (MRSE) strains, and agr Type I was the most frequent one. Among all biofilm-positive strains, 3 common types (CTs) and 7 single types (STs) were determined;  CT1 and CT2 were the most common types among the strains isolated from hospitalized patients and healthy people.
Conclusion: These findings indicated the presence and persistence of diverse clone types of biofilm-producing S. epidermidis strains with common types of PhP, agr, and SCCmec in the hospital and the community of Isfahan.

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Backgrounds: Nowadays, the need for replacement of new drug structures is felt more than ever due to the spread of microbial resistance. S-triazoles are significant five-membered heterocyclic scaffolds due to their wide range of biological activities.
Materials & Methods: A new series of Schiff bases (5a-f) were synthesized by the reaction of 4-amino-S-triazoles (3a-c) with furan and benzaldehyde 4(d-e). Then a novel series of triazole thioglycosides (7a-f) were synthesized by the reaction of Schiff bases (5a-f) and T-O-acetyle-α-D-glucopyranosyle-Br in the presence of potassium carbonate as a weak base in acetone. The structure of the products was confirmed by FT-IR, H-NMR, and C-NMR assays. The antimicrobial properties of the newly synthesized compounds were studied against four bacterial strains, including Bacillus cereus, Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli, and two fungal strains, including Aspergillus niger and Candida albicans.
Findings: The synthesized compounds exhibited better antifungal activity than antibacterial activity, espetially 7d. Among all the compounds, the compound 7d was found to have the highest activity against C. albicans with IZ=18±0.7 mm, MIC=250 mg/mL, and MFC= 250 mg/mL.
Conclusion: The present study results indicated that compounds containing S-triazole had the potential to be used in a wide variety of new antifungal formulations.

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Backgrounds: Listeria monocytogenes is an opportunistic pathogen causing listeriosis, its pathogenicity is due to the presence of virulence factors including InlA, InlB, PlcA, PlcB, ActA, Iap, and Hly. The purpose of this study was to evaluate the formation of biofilm and its association with serotypes and virulence factors in L. monocytogenes isolates.
Material and Methods: In this study, 51 L. monocytogenes isolates were collected from blood, urine, feces, placenta, rectum, and vagina samples as well as livestock and food samples. Biofilm production was measured using microtiter plate assay, and virulence genes were identified by PCR method.
Findings: Out of 51 isolates, 27 (52.9%) were non-biofilm producers, 17 (33.3%) were weak biofilm producers, four (7.8%) were medium biofilm producers, and three (5.9%) were strong biofilm producers. According to this study results, different L. monocytogenes strains could form biofilm with various intensities. The actA, flaA, inlJ, inlA, and plcB genes were observed in all the isolates. The frequency of the hlyA, plcA, iap, inlB, and inlC genes among the isolates was 90.2, 94.1, 98, 88.2, and 82.4%, respectively. There was no significant correlation between the presence/absence of virulence genes in biofilm producing and non-biofilm forming isolates, except for the inlC and iap genes, which showed a significant correlation with the ability to form biofilm.
Conclusion: Due to the high prevalence rate of biofilm formation among the isolates and the importance of biofilm production in medical surfaces and food industries, eradication of biofilm-forming isolates is important.
 

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Passive walkers are robots, which perform a walking like, stable limit cycle on small slopes without any external control. This concept was published on 90’s by McGeer and there are lots of related researches going on in the past few years. Keeping in mind the novelty of the concept, investigating the effects of structural parameters on walking performance and finding their optimums, simulating the biped and establishing a trend to its optimal design and build, and finally doing experimental researches, would be of a great concern. In this research, a deployed model of biped that can be built has been considered, and then its walking performance sensitivity such as efficiency, stability and robustness on uneven trains due to variation of structural parameters and their optimum limits have been investigated. It was shown that the foot arc radius and center of mass height have the most important effect on walking performance. After comparing the results with previous researches and doing simulations in MSC.ADAMS software, an optimum design trend has been suggested. At the end based on experimental results, it was shown beside optimization of structural parameters, considering the impact condition as well would be very important to achieve optimal walking.

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One of the most important challenges in the field of structural health monitoring and non-destructive testing is to assess some features of damages in structures, like the shape of damaged region. To reconstruct the shape of damage there are different methods in tomography. Already, researchers have used two general types of shape reconstruction techniques: transform based methods and algebraic reconstruction methods. Both methods suffer from some disadvantages like high sensitivity to incomplete data sets, bulky and expensive scanning hardware or low image resolution. In this work, a novel method to find the shape of damage via polygon reconstruction technique in tomography using the Radon transform is introduced. In this technique, damaged region is approximated by a polygon which the number of its sides is chosen arbitrarily, and the aim is to find this polygon’s vertices. To achieve this goal, an aluminum plate with a triangular hole as the damage was modeled in software. Then beams of guided Lamb wave were propagated toward the damaged region using arrays of piezoelectric transducers in just a few numbers of angles. Finally the polygon’s vertices were determined by processing the reflected signals from the damaged region. The results confirmed the efficiency of the proposed method.

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The fixtures play a significant role in harnessing the metal sheets in the assembly stage. The high flexibility of the metal sheets and the initial deviation in the pressed sheets cause deviation in the final product. Using the optimal layout of the clamping points in the fixture can reduce the deviation effectively and raising the final product quality. On the other hand, the cost of construction is intensively influence by the number of clamps, rising the number of clamps causes the cost of construction to increase and reducing it cause the deviation in the final product to increase. Therefore, the number of clamps should be considered in the optimal design of the fixture. It is challenging to achieve optimal design for fixture due to the difficulty in predicting sheet behavior and computational constraints. In this paper the relationship between the initial deviation of sheet and the deviation of final product is investigated and a method is proposed by using ant colony algorithm and finite element method for optimizing the position of the clamping points to reducing the deviation of the product after assembly with considering the minimizing the number of clamping points. Finally the proposed method is applied to a simple square sheet with initial deviation and based on the cost function, the number of clamping points and their position are optimized. The results show that reducing the amount of sheet deviation in the fixture causes reduce the deviation of final product.

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Data Envelopment Analysis (DEA) is a powerful technique for measuring efficiency. The traditional DEA approach is applicable when inputs and outputs are certain. Since, some input and output data, such as CO2 emission are often imprecise or vague in real world, this approach cannot be used efficiently. Therefore, this study uses the fuzzy data envelopment analysis to measure carbon-environmental efficiency. The results show that the average interval carbon-environmental efficiency is 75.90 percent in the sample and period under study. In addition, the minimum and maximum carbon- environmental efficiency scores in Iran are 61 and 74 percent, respectively, which indicates low environmental efficiency in Iran compared to other countries.  Accordingly, using inputs optimally and lowering dependency on resources are recommended for increasing the carbon-environmental efficiency.