83 research outputs found

    Conceptual model of effect and form of architecture and structures

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    In addition to having the most stability, the first task that every building has to do is having the economic factor, which is one of the concerns of the builders. One of the tools for the advent of architectural form is the structure. This is despite the fact that the limitless artistic thinking has very little unity with numerical and enclosed numerical thinking in the framework of structural engineering math. The date of the interaction between the architecture and the structure implies that the industrial revolution and the consequences are considered as a major event contributed to the further disruption of the relationship between architecture and structural engineering. In many studies, the form of architecture, structure, and nature have been distinctly examined, but in the present study, it was tried to link these two relatives, structures and architectures from the form in nature using technology. First, the evolution of structural and architectural harmony in different historical periods was studied. Then, we focused on natural patterns such as human, plant, and animal structures and finally, works by the Spanish architect, Gullart, was analyzed as an external case study. Regarding the above, this study has achieved a model and a strategy to enhance the quality of construction and interaction of structure and architecture using the structural structure in the existing forms in nature.Keywords: Architecture, Structures, Nature, Architectural and Structural Interactio

    Cloning and optimization of expression and purification of the catalytic domain of adenylate cyclase toxin from an Iranian strain of Bordetella pertussis

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    زمینه و هدف: توکسین آدنیلات سیکلاز (Adenylate cyclas Toxin= ACT) یکی از فاکتور های ویرولانس ترشحی و ایمونوژنیک بوردتلا پرتوسیس است که دارای یک دمین کاتالیزوری با 400 اسید آمینه، به نام AC، در ناحیه N- ترمینال خود می باشد. این دمین با تحریک غیر قابل بازگشت cAMP در سلول یوکاریوت نقش مهمی در ایجاد بیماری سیاه سرفه ایفا می کند و به عنوان یک ابزار زیست شناسی سلولی بوده و در داروهای ضد سرطانی نیز مورد استفاده قرار گرفته است؛ لذا هدف از این مطالعه، دستیابی به بیان بالایی از ناحیه AC به منظور بررسی خواص آنتی ژنیک آن در جهت استفاده از آن در واکسن، ادجونت و یا تهیه ی کیت های تشخیصی می باشد. روش بررسی: در این مطالعه تجربی، قطعه AC، توسط واکنش PCR تکثیر و در وکتور pET28a کلون و در باکتری E.coli BL21(DE3)، بیان و پس از بهینه سازی شرایط بیان، آنالیز پروتئین توسط ژل SDS PAGE و وسترن بلات انجام و سپس تخلیص آن بر روی ستون کروماتوگرافی (NI-NTA) صورت پذیرفت. یافته ها: قطعه AC با موفقیت در وکتور بیانی pET28a کلون شده و تحت سیستم بیانی القا شونده توسط IPTG با غلظت 5/0 میلی مولار، پس از 4 ساعت در دمای 37 درجه می تواند قابلیت حداکثر بیان با بازدهی 25 میلی گرم بر لیتر و خلوص 95 را داشته باشد. نتیجه گیری: این مطالعه نشان داد با القای تنها 5/0 میلی مولار IPTG، می توان بیان بالای دمین کاتالیزوری پروتئین ACT، با حداکثر میزان خلوص را دارا بود که این میزان برای اکثر کاربردهای تحقیقی و تشخیصی مناسب است

    Antimicrobial resistance profile and presence of class I integrongs among Salmonella enterica serovars isolated from human clinical specimens in Tehran, Iran

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    International audienceBACKGROUND AND OBJECTIVES: Salmonella is one of the leading causes of food-borne diseases. Increasing occurrence of antimicrobial resistance, especially multidrug-resistance, in Salmonella serovars is a major public health problem worldwide. This study was carried out to detect class I integrons and antibiotic resistance profiles in clinical isolates of Salmonella serovars collected from seven hospitals in Tehran during November 2009 to June 2010. MATERIALS AND METHODS: Antibiotic susceptibility profile of 19 antibiotics against 58 Salmonella isolates commonly used in humans was determined using disk diffusion assay. Minimum inhibitory concentration against ceftriaxone and ciprofloxacin was studied. PCR assays were used to detect class I integrons. RESULTS: Among 58 Salmonella isolates, 72.4% were Salmonella enterica serovar Enteritidis, 8.7% were Salmonella enterica serovar Typhimurium and 18.9% were other serovars. Of the total 58 Salmonella serovars, 43 (74.1%) were multidrug-resistant and showed resistance to three or more antibiotic families. Class I integrons were identified in 38 (88.3%) MDR Salmonella isolates. Ciprofloxacin minimum inhibitory concentration ranged between 0.125-2 g/ml for four isolates and other four isolates exhibited resistance to ceftriaxone (MIC 64-256 g /ml). CONCLUSION: The high prevalence of class I integrons was seen in our MDR Salmonella isolates and class I integrons might play an important role in the dissemination of antimicrobial resistance determinants

    Molecular diversity of hpd gene in clinical isolates of Haemophilus influenzae

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    Infections due to Haemophilus influenzae result in tremendous global morbidity. The conjugated vaccines against H. influenzae type b (Hib) have dramatically reduced the incidence of invasive Hib disease in the routine immunization of infants. The several proteins used as vaccine candidates for this pathogen, but they don't produce efficient immune in animal models against all strains of H. influenzae. This study aimed to determine the diversity of hpd gene nucleotide sequences of Iranian native clinical isolates of H. influenzae as a native vaccine candidate compared to standard strains. Twenty isolates of H. influenzae recovered from different clinical specimens of patients admitted to Milad and Imam Khomeini hospitals, Tehran, Iran. Then, isolates detected and identified as H. influenzae using biochemical tests, and further confirmation through omp6 gene PCR. The hpd gene was amplified by PCR using gene-specific primers, and the amplicons digested with EcoR1. For four isolates, the Amplicon of hpd gene sequenced, and the sequences aligned with sequences harbored in GenBank. Subsequently, sequences were submitted to the EMBL site (http://www.ebi.ac.uk/embl/). EcoR1 restriction enzyme pattern was the same among the 19 clinical isolates, and only one isolate was different. That different one with 3 out of 19 isolates were sequenced. The results showed that the nucleotide sequences and the deduced amino acid sequences for protein D in clinical isolates were highly conserved with similarities >95. In conclusion, regarding high similarity up to 99 in clinical isolates, protein D can be a novel vaccine candidate against all types of H. influenza from Iran. This finding should be proved with more isolates, and also, evaluate the immunological features of protein D in animal models. © 201

    Isolation and genetic characterization of metallo-β-lactamase and carbapenamase producing strains of Acinetobacter baumannii from patients at Tehran hospitals

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    International audienceBACKGROUND AND OBJECTIVE: Carbapenems are therapeutic choice against infections caused by gram-negative bacilli including strains of Acinetobacter baumannii. Resistance to these antibiotics is mediated by efflux pumps, porins, PBPs and ß-lactamases. The aim of this study was to determine the possibility of existence of MBLs, OXAs and GES-1 betalactamase genes among clinical isolates of Acinetobacter collected from Tehran hospitals. MATERIAL AND METHODS: Two hundred and three Acinetobacter isolates were collected from patient at Tehran hospitals. The isolates were identified using biochemical tests. The susceptibility to different antibiotics was evaluated by disk diffusion method and MICs of imipenem were determined using Micro broth dilution method (CLSI). PCR was performed for detection of bla(VIM-2), bla(SPM-1), bla(IMP-2), bla(GES-1), bla(OXA-51), bla(OXA-23) betalactamase genes. Clonal relatedness was estimated by PFGE with the restriction enzyme SmaI. RESULTS AND CONCLUSION: Of 100 isolates of imipenem resistant Acinetobacter spp. collected from Tehran hospitals in 2009 and 2010, 6 isolates produced metallo-beta-lactamases and 94 isolates produced OXA-type carbapenemase. The bla(SPM-1), bla(GES-1), bla(OXA-51), bla(OXA-23) genes were detected by PCR among 6, 2, 94 and 84 isolates of A. baumannii, respectively. The MICs of isolates to imipenem were 8-128 µg/mL. PFGE analysis of 29 bla(OXA-51) and bla(OXA-23)-positive A. baumannii isolates gave 6 different patterns. This is the first report of SPM-1 and GES-1 beta-lactamase producing A. baumannii. Production of the OXA-23, OXA-51, GES-1 and SPM-1 enzyme presents an emerging threat of carbapenem resistance among A. baumannii in Iran

    Development of a modified DNA extraction method for pulsed-field gel electrophoresis analysis of Staphylococcus aureus and enterococci without using lysostaphin

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    A modified pulsed-field gel electrophoresis (PFGE) protocol was developed and applied to clinical isolates of Staphylococcus aureus and enterococci to reduce the cost of using lysostaphin. This protocol reduces the expenses of PFGE typing of S. aureus and enterococci as it removes the use of lysostaphin during the spheroplast formation from these bacteria

    Evaluation of phenotypic and genotypic characteristics of carbapnemases-producing enterobacteriaceae and its prevalence in a referral hospital in Tehran city

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    Background & Objective: Carbapenem-resistant Enterobacteriaceae is a growing concern worldwide including Iran. The emergence of this pathogen is worrying as carbapenem is one of the �last-line� antibiotics for treatment of infections caused by multi drug resistant gram- negative bacteria. The main objective of this study was to determine the prevalence of carbapenem-resistant Enterobacteriaceae in a referral hospital in Tehran, Iran. Methods: In this study, all positive isolates of Enterobacteriaceae recorded in blood, urine, and other body fluids were studied during April 2017 to April 2018 in a referral hospital in Tehran. All cases of resistance to carbapenems were first tested by modified Hodge test. All cases with positive or negative test, after gene extraction, were examined genotypically based on the primers designed for the three Klebsiella pneumoniae carbapenemase (KPC), New Delhi metallo-β-lactamase (NDM), and OXA-48 genes by conventional PCR method. Results: 108 isolates (13.6) were resistant to all cephalosporins as well as to imipenem and meropenem. In a genotypic study, including 45 isolates, 13 isolates were positive for OXA-48 gene, 11 isolates for OXA-48 and NDM genes, 11 isolates for OXA-48, NDM and KPC genes, 4 isolates for OXA-48 genes and KPC, 3 isolates for NDM, one isolate for KPC. On the other hand, two isolates were negative for all three genes examined. Conclusion: OXA-48 gene was one of the most common genes resistant to carbapenems in Iran. According to studies, the prevalence of antibiotic resistance in Iran is rising dramatically, which reduces the choice of antibiotics to treat severe infections in the future. © 2020, Iranian Society of Pathology. All rights reserved

    Prevalence, risk factors, and epidemiology of food-borne botulism in Iran

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    Background: Botulism is a severe neuroparalytic disease caused by toxins produced by several Clostridium species. This work presents the surveillance results of botulism in Iran, with the distribution of the cases by regions and by vehicle of transmission. Methods: We describe the findings of the Centers for Disease Control and Prevention (CDC) surveillance on 2037 suspected cases of food-borne botulism during 2007�2017. Results: A total of 252 (12.3) cases were confirmed to food-borne botulism. The mean annual incidence per 100,000 Iranian Natives was 7.1 cases for male individuals and 3.3 cases for female individuals. All botulism events were confirmed to be foodborne. The most commonly implicated food was home-prepared traditional processed fish product, followed by the consumption of commercially canned products and non-pasteurized dairy products. Forty-eight (19) fatal botulism were reported which, the case-fatality rate declined from 4.5 to 0.7 during the study period. Conclusion: Laboratory-based diagnosis of botulism is an imperative procedure to elucidate cases, particularly food-borne botulism, to identify toxins in food and confirm clinical diagnosis, helping sanitary control measures. In addition, educational materials related to botulism prevention should be disseminated to different communities. © 2020 Atlantis Press

    Variability in gene cassette patterns of class 1 and 2 integrons associated with multi drug resistance patterns in Staphylococcus aureus clinical isolates in Tehran-Iran

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    Background: To investigate antibiotic resistance, the occurrence and distribution of class 1 and 2 integrons in multidrug- resistant Staphylococcus aureus isolates from hospitals in Tehran, Iran. The isolates were examined for susceptibility to antimicrobial agents. The mecA gene, class 1 and 2 integrons were detected by PCR. Integrase positive strains were further analysed for the presence of resistance gene cassettes using specific primers and were sequenced. Results: Among 139S.aureus isolates, 109 (78.4 ) and 112 (80.5 ) strains were considered as multidrug resistant and mecA positive, respectively. Class 1 integrons and internal variable regions were found in 72.6 (101/139) and 97 (98/101) and class 2 integrons and variable regions also in 35.2 (49/139) and 65.3 (32/49) of S.aureus clinical isolates, respectively. Twelve distinct cassette arrays were found, containing genes encoding resistance to β-lactams, aminoglycosides, streptothricin, trimethoprim, chloramphenicol,a putative glucose dehydrogenase precursor and a protein with unknown function. Gene cassette arrays aadB, aadA2 and dhfrA1-sat2-aadA1 were common in S.aureus isolates. We detected a completely new gene cassettes which contained aadB, oxa2, aacA4, orfD-aacA4-catB8, aadB-catB3, orfD-aacA4 and aadB-aadA1-cmlA6 of class 1 and dhfrA1-sat2-aadA1, dhfrA11, dhfrA1-sat2 of class 2 integrons. Conclusions: This is the first study to report carriage of class 1 and 2 integrons and associated gene cassettes among in S.aureus isolates from Iran. © 2015 Mostafa et al

    Genetic profile variation in vaccine strains and clinical isolates of bordetella pertussis recovered from iranian patients

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    Background: Re-emergence of pertussis has been reported in Iran despite a high rate of vaccination coverage. Low efficacy of the vaccine might be due to the genetic divergence between clinical versus vaccine strains. In the current study, the genetic profiles of clinical isolates and vaccine strains of Bordetella pertussis (B. pertussis) were assessed by using Pulsed Field Gel Electrophoresis (PFGE). Methods: Following phenotypic and molecular identification of isolates, XbaIdigested genomic DNA of 5 clinical isolates, 2 vaccine strains and a Tohama I strain were analyzed by PFGE along with B. parapertussis as a control. Results: Seven distinct PFGE profiles were found among all examined isolates/ strains. In 5 clinical isolates, 4 profiles were identified whereas the vaccine strains displayed 2 distinct profiles. The reference strain, Tohama I had a distinct profile. Vaccine and clinical profiles had low similarity, with relatedness of approximately 40. Conclusion: The genetic profiles of B. pertussis were different between circulating isolates and vaccine strains used in the national vaccination programs. Since new genetic profiles of B. pertussis can be disseminated periodically, the profiles of isolates circulating in the population should be monitored over the course of the re-emergence. © 2014, Avicenna Journal of Medical Biotechnology. All rights reserved
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