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Bacillus licheniformis is a gram-positive, endospore-forming, saprophytic and facultative anaerobe that is resistant to heat and environmental conditions. This study was the first to isolate and confirm B. licheniformis as a cause of bovine mastitis in Iran. In the summer of 2020, 105 samples of mastitic milk were collected from dairy farms around Tehran and sent to the microbiology laboratory of the Faculty of Veterinary Medicine at the University of Tehran. The bacterial pathogens were identified using selective and differential culture media and confirmed by PCR to contain the toxin synthetase genes licA, licB and licC in mastitic isolates of B. licheniformis. Resistance patterns to 19 antibiotics were determined for two isolates of B. licheniformis. Staphylococcus aureus and Escherichia coli were identified as the most important organisms in the samples. B. licheniformis was isolated from the two samples containing all three genes. Both isolates were resistant to streptomycin, trimethoprim-sulfamethoxazole, cefixime, ampicillin, bacitracin, clindamycin, and gentamicin. B. licheniformis was reported for the first time in Iran as a cause of bovine mastitis with clinical symptoms. The first isolation of toxin-producing strains of B. licheniformis from mastitic cows in Iran raises concerns about the safety of dairy products. In principle, selected strains with toxigenic potential should not be used as feed additives and animal feed. However, whole genome sequencing is proposed to search for genes coding for toxins. [ABSTRACT FROM AUTHOR]

Abstract The protective actions of components isolated from Aloe arborescens Miller var. natalensis Berger (Kidachi aloe in Japanese) on streptozotocin (Sz)-induced necrosis of B cells in the pancreatic islets of [...]

Background: Salmonellosis is one of the most important zoonotic diseases in humans and animals worldwide. Aims: The main objective of this study was to report serovars, clonal relatedness, and antimicrobial resistance of Salmonella strains isolated from human, different animal hosts including pigeons, broilers, cattle, camel, parrots, and hamsters in different regions of Iran. Methods: Twenty-four Salmonella isolates were confirmed at the genus level by biochemical tests and polymerase chain reaction (PCR) by showing the presence of invA gene. Serovars were determined and their clonal relatedness was assessed by RAPD-PCR and antibiotic resistance profiles. Results: Overall, Salmonella Typhimurium was the most prevalent serovar (45.8%, 11/24), which was recovered from humans, pigeons, and camels. Salmonella Enteritidis (29.2%, 7/24) was the second common serovar that was recovered from cattle, broilers, humans, and hamsters. Salmonella Infantis (12.5%, 3/24) belonged only to broiler sources, and Salmonella Seftenberg (12.5%, 3/24) was isolated from eggs and a parrot. The major RAPD pattern was VI (33.3%) in which the two S. Typhimurium isolates (belonged to humans and pigeons) exhibited similarity in both RAPD pattern and resistance profile. Antimicrobial susceptibility test showed full resistance to tylosin and erythromycin (100%, 24/24). All isolates (100%, 24/24) were susceptible to ceftriaxone, cefixime, and gentamicin. In total, 75% of the isolates were multi-drug resistant (MDR) and revealed 15 different antimicrobial resistance profiles (R-type). Conclusion: This study supports the potential transmission of Salmonella serovars via animal contacts. Thus, it is necessary to establish a national systematic monitoring program with one health approach for controlling Salmonella infections. [ABSTRACT FROM AUTHOR]

A Ru-SiO2 intermediate layer is introduced between Ru and recording layers to reduce the intermediate layer thickness of CoCrPt-SiO2 perpendicular recording media. A structural analysis revealed that the Ru-SiO2 intermediate layer enhanced the oxide segregation in the initial growth region of the recording layer.

A study was conducted to analyze the influence of CoCrZr seed layer on the noise characteristics and microstructure of CoCrPT media. The films were deposited on chemically enforced soda-lime glass substrates by direct current magnetron sputtering. Experimental results indicated that the microstructure is very sensitive to the zirconium content and affects the microstructure of the magnetic layer.

The thermal decay of written bits in CoCrPt/CrTi thin film media for high density longitudinal magnetic recording is examined using a magnetoresistive head at room temperature. A decay in signal output over time is observed for the media with a thin magnetic layer less than about 14 nm thick and the media noise increases. The thermal stability factor Ku [center dot] V/k [center dot] T of these media is estimated to be less than about 100. The signal decay and noise increase are more serious at higher linear recording densities. These results are consistent with the results of a micromagnetic simulation taking into account the thermal aftereffects. These characteristics suggest that media with a large magnetic anisotropy constant Ku will be required to realize high storage densities of over 10 Gb/[in.sup.2].

Magnetic and recording characteristics of CoCrPt media with a CrTiB underlayer was investigated. Higher coercivity Hc and coercive squareness [S.sup.*] were obtained compared with the media that had a CrTi underlayer. The overwrite property of the media was also improved by adding boron, while the change in media noise was very small. Transmission electron microscopy analysis showed that the crystal grain-size dispersion in the magnetic layer was reduced by about 15% when boron was added to the underlayer, and the average grain size was almost the same as when the CrTi underlayer was used. The higher [S.sup.*] and improved overwrite property that resulted when using a CrTiB underlayer should be attributed to the reduction in the grain size dispersion, which provides a narrower switching field distribution.

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A Ru–SiO2 intermediate layer was introduced between the Ru and recording layers to reduce the intermediate layer thickness of CoCrPt–SiO2 perpendicular recording media. A structural analysis revealed that the Ru–SiO2 intermediate layer enhanced the oxide segregation in the initial growth region of the recording layer. A micromagnetic simulation and magnetic property measurements indicated that the Ru–SiO2 intermediate layer reduced the intergranular exchange coupling in the initial growth region of the recording layer without magnetic anisotropy degradation. We reduced the intermediate layer thickness down to 9.1 nm by using the Ru–SiO2 intermediate layer while maintaining the signal-to-noise ratio. [ABSTRACT FROM AUTHOR]

Effects of bcc and hcp intermediate layers between a bcc–Cr[sub 80]Ti[sub 20] underlayer and a hcp–CoCrPtTa magnetic layer on magnetic and recording characteristics were investigated. The medium without an intermediate layer has a low coercivity H[sub c] of 0.27 kOe due to the perpendicular orientation of the c axis of the CoCrPtTa layer. By introducing a 5-nm-thick intermediate layer of bcc–Cr[sub 60]Mo[sub 40] or hcp–Co[sub 70]Cr[sub 30], the c axis of the CoCrPtTa layer can be effectively in-plane oriented, resulting in a high H[sub c] of 2.71–2.87 kOe and a coercive squareness S[sup *] of 0.72–0.81. The medium with the Cr[sub 60]Mo[sub 40] layer has lower media noise than the medium with the Co[sub 70]Cr[sub 30] layer. This lower noise is considered to be caused by the small grain size of 10.4 nm. The addition of the thin Cr[sub 60]Mo[sub 40] intermediate layer is therefore effective to obtain both high H[sub c] and low noise in the CoCrPtTa media with the CrTi underlayer. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]

This study aims at molecular identification of Salmonella Infantis isolated from backyard chickens and the detection of their antibiotic resistance genes. A total of 46 Salmonella-suspected samples isolated from backyard chickens of northern Iran were collected. Serotyping was done by the traditional method and then confirmed by PCR. Antimicrobial susceptibility of the isolates against 13 antimicrobial agents was determined by the standard disk diffusion method. There were 44 samples identified as Salmonella. Serotyping results showed that all 44 isolates belonged to serogroup C1 and serovar Infantis. The most resistance observed was to tetracycline and doxycycline (100%), chloramphenicol (79%) and florfenicol (72%). The floR, catI, tetA and tetG genes were used for the detection of florfenicol chloramphenicol and tetracycline resistance. In order to identify the phenotypic resistance in strains which showed resistance genes by PCR, colony PCR and culture on plates each containing antibiotic was performed simultaneously. All the Salmonella Infantis resistant toflorfenicol and chloramphenicol harbored floR and catI. None of the Salmonella resistant to tetracycline carried tetA or tetG. The result of colony PCR and culture in antibiotic medium confirmed the results of PCR and indicated phenotypic resistance in these samples. [ABSTRACT FROM AUTHOR]