42 research outputs found

    Microstructural Control and Characterization of Bi2V0.9Cu0.1O5.35 (BICUVOX) Ceramics

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    The widespread commercialization of solid-oxide fuel cells (SOFCs) and solid-oxide electrolyte cells (SOECs) is primarily limited by material degradation issues related to the required high temperature operation (\u3e800°C). Applications of stabilized zirconia based electrolytes, which are the most commonly used oxide ion conductors, have been limited to this high temperature regime due to its low oxygen ion conductivity below 800°C. Solid electrolytes made of the BIMEVOX compositional family of materials (Bi2MexV 1-xO5.5-delta where Me=Cu, Co, Mg, Ni, Fe...) exhibit high oxide ionic conductivity similar to YSZ at a low temperature (300--600°C). Among these materials copper-substituted bismuth vanadate (Bi2V0.9Cu0.1O5.35, BICUVOX), was reported to have the highest ionic conductivity at 400°C (0.02 S/cm). It\u27s one of the most important drawbacks of using BICUVOX, as a SOFC electrolyte is the low mechanical strength, which makes it unusable for most electrolyte supported applications. This research aims at improving mechanical strength by careful control of synthesis processing and sintering processes, thus making BICUVOX a viable material option for intermediate temperature SOFC. A co-precipitation method was used to synthesize submicron BICUVOX powder. The powder was utilized to fabricate a thin (\u3c 250 microm) BICUVOX electrolyte membrane, with 2.5 cm2 active area and high mechanical strength. The fabricated BICUVOX membranes were densified to 97% theoretical density at lower sintering temperature and shorter time (675°C/1 h), and shows fine grain size (\u3c1.5microm) and high mechanical strength (159 MPa)

    Evaluating the Geotechnical and Geophysical Characteristics of Expanding Districts in Tehran Using Field Experiments

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    Considering the increasing population growth and the rapid growth of urbanization and pollution in the environment, providing zoning maps and urban engineering geology seem to be important. The rapid construction growth of cities, as well as the confrontation with events such as earthquakes and failure to observe the geological and geotechnical issues, has caused many engineering problems. The use of geophysical methods not only cannot lonely provide us a complete and comprehensive information on the geotechnical conditions of the earth but also has many disturbances in urban areas, and its use in urban centers is almost impractical. Therefore, it seems that the best way of examining and interpreting the geotechnical characteristics of a site, especially in urban areas, is the use of suspicious data. Therefore, performing geotechnical studies and geotechnical zoning can be useful for retrofitting buildings and engineering structures and reducing their risks. Hence, zoning studies are conducted in this research in order to better recognize the technical soil status for safe construction due to rising the population of Tehran in recent decades and the concentration of population in certain areas of Tehran, especially in the eastern and western regions (districts 4 and 22). In this study, different geotechnical field tests such as standard penetration test (SPT), cone penetration test (CPT) were used to estimate parameters such as adhesion coefficient (C), internal friction angle ( ), Young modulus (E). Other common experiments with conventional geophysical experiments, such as in good experiments, refractive and CSSW were applied to estimate geophysical parameters of bedrock depth and shear wave velocity for zoning these areas

    Antimicrobial Susceptibility Profile of Enterococcus Species Isolated from Companion Birds and Poultry in the Northeast of Iran

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    Enterococci are Gram-positive facultative anaerobic bacteria commonly found in the gastrointestinal tract of the mammals and birds. These cocci are isolated from urinary tract infections, bacteremia, endocarditis, and burn wounds in humans. The evolution of antibiotic-resistant enterococci raised a problem due to the possibility of the transmission of these organisms between poultry and human. Regarding this, the present study was conducted to evaluate the prevalence of Enterococcus species among companion birds and poultry in the Northeastern of Iran and determine the antibiotic susceptibility profile of enterococci. To this end, oral and cloacal swabs were collected from 150 caged birds. Antibiotic susceptibility profile was determined using the standard disk diffusion method. The results revealed that out of 150 samples, 56 (37.33%) cases contained enterococci. Most of the specimens (25.33%) were Enterococcus faecalis isolated from 6.66% of the samples. Additionally, 2.66% and 1.33% of the samples were contaminated with Enterococcus mundtii and Enterococcus gallinarum, respectively. Furthermore, Enterococcus malodoratus and Enterococcus raffinosus were isolated from 0.66% of the samples. The results revealed that all of the isolates of E. faecalis and E. faecium were resistant to more than five antimicrobial agents. Most of E. faecalis and E. faecium isolates showed resistance to Cefazolin, Tiamulin, Flumequine, and Cephalexin. Accordingly, the majority of the isolates had multidrug resistance to the tested antibiotics. In conclusion, the presence of multidrug-resistant enterococci in the birds living close to humans requires thorough observations due to the transmission of these organisms to humans

    H Syndrome Masquerade as Rheumatologic Disease

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    Background  H syndrome is an autosomal recessive genodermatosis with a low prevalence which is caused by a mutation in SLC29A3 gene. This disorder is characterized by sclerotic, hyperpigmented, hypertrichotic cutaneous plaques with systemic involvement including: hepatosplenomegaly, heart anomalies, hearing loss, hypogonadism, low height, and hyperglycemia. Case Presentation  Here we have presented two cases of H syndrome that have been misdiagnosed and mismanaged as rheumatologic disease. The first case had been represented with sclerotic skin lesions and diagnosed as morphea, and second one with chronic and recalcitrant to treatment arthritis as juvenile idiopathic arthritis. Conclusion  H syndrome is an autosomal recessive genodermatosis that has been recently recognized with a variety of manifestations and overlapping features with other diseases. Increase the knowledge of physicians for wide spectrum manifestations of this syndrome along with reporting the misdiagnosis of this condition can increase the accuracy of physicians for its better identification. This time our cases masquerade as rheumatologic diseases

    Isolation and toxin gene detection of Clostridium (Clostridioides) difficile from traditional and commercial quail farms and packed quail meat for market supply – Short communication

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    Clostridium (Clostridioides) difficile is a Gram-positive anaerobic rod-shaped bacterium and the main cause of nosocomial diarrhoea in humans. In recent years, the transmission of C. difficile from environmental reservoirs (e.g. food) to humans has become a major focus of research. The aim of this study was to investigate the prevalence and corresponding toxin genes of C. difficile in faecal samples and meat of quails. Thirty samples of packed quail meat in Mashhad, Iran and 500 faecal samples (pooled to n = 5) were collected on quail farms in the Northeastern Khorasan region for further investigation. Of 100 pooled quail faecal samples 10% showed cultural growth of C. difficile. In meat samples two out of 30 specimens (7%) showed cultural growth. In six of ten isolates from faecal samples toxin genes (tcdB and tcdA) were present, while four isolates harboured no toxin genes. However, in meat isolates no toxin genes were present. Mutations in the tcdC gene were not detected, indicating that ‘hypervirulent’ strains such as RT027 and RT078 were not present. The data suggest that quail and quail products might hold a potential for the spread of C. difficile

    Rethinking the role of alpha toxin in Clostridium perfringens-associated enteric diseases: a review on bovine necro-haemorrhagic enteritis

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    Varicella Zoster Infection in Infancy (A Very Rare Case Report)

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    Background: Herpes zoster occurs due to reactivation of varicella zoster-virus (VZV) that is latent in dorsal root ganglion cells after primary varicella infection. It can occur in any age but is very rare during infancy. Acquisition of this virus in utero or early after birth may result in infantile herpes zoster. Case report: Here, it is aimed to report an infant with herpes zoster whom his mother had developed varicella two years before pregnancy. Conclusion: Despite the rarity of shingles in infants after birth, any infant who has a vesicular lesion in a particular neurological dermatome should be aware of the disease

    An outbreak of yolk sac infection and dead-in-shell mortality in common canary (Serinus canaria) caused by Klebsiella pneumoniae

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    Summary Yolk sac infection (YSI) and dead-in-shell mortality caused by Enterobacteriaceae in birds are not a rare phenomenon, however there are only a few reports indicating the association between these conditions and Klebsiella spp. among canary chicks (Serinus canaria). There have been reports of high mortality among 1-3 day old canary chicks in an indoor flock of canaries. In order to study the causative agent, yolk sac samples from dead-in-shell and day-old canary chicks were cultured. Klebsiella pneumonia was isolated and identified based on biochemical tests and using genus and species-specific multiplex PCR and later tested for their susceptibility to 13 antimicrobial agents. The isolates showed susceptibility to Gentamycin, Chloramphenicol, Florfenicol and Streptomycin

    Molecular diagnosis of Mycoplasma conjunctivae in an outbreak of infectious keratoconjunctivitis in sheep

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    Summary Infectious keratoconjunctivitis (IKC) is a painful, highly contagious ocular disease in sheep and goats. This study was carried out for identification and characterization of causative agent of ocular disease in a sheep flock consisting of 300 ewes in Mashhad, Iran. Several ocular swabs were taken from affected animals. The samples were pooled and processed in a laboratory for isolation of suspecious agent. Following inoculation of the pooled sample in PPLO broth and agar, turbidity and growth of colonies were observed in them, respectively. Sequencing of the 1013 bp PCR product of 16S rDNA gene revealed that the causative agent of the outbreak has 100% sequence identity to Mycoplasma conjunctivae. Based on our knowledge this is the first documented report of isolation and molecular characterization of M. conjunctivae in Iran
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