An investigation was conducted for isolation, identification and determination of antibiotic sensitivity of Avibacterium paragallinarun, the causal agent of infectious coryza, from layer chickens. A total of 21 samples with characteristic symptoms of the disease were collected from a Hatchery of Gazipur. Tissue specimens obtained aseptically from swollen infra orbital sinus and tracheal swab were processed, of which, 3 were found positive while the rest 18 were negative. Isolation of bacteria was performed by first putting the specimen in Nicotinamide adenine dinucleotide (NAD) enriched phosphate buffer broth, anaerobically incubated for 24 hours followed by culturing loopful of broth on Blood agar (BA) and Chocolate agar (CA) plates enriched with NAD and streaked with feeder organism of Staphylococcus. aureus. On 24 hours of anaerobic incubation (candle jar method), dew drop satellite colonies of A. paragallinarum were visible on the culture plates. Cultural characteristics of bacteria as well as their staining, morphological, motility and biochemical properties such as sugar fermentation, MR and V-P tests, Indole production and catalase tests were recorded for identification. Further, antibiogram study revealed that the isolates were sensitive to Ciprofloxacin, Chloramphenicol and Gentamicin but resistant to Ampicillin, Amoxycillin, Oxytetracycline, Erythromycin and Sulphamethoxazole. DOI: http://dx.doi.org/10.3329/mh.v3i1.19769 Microbes and Health, June 2014. 3(1): 9-11

In this article, we have theoretically demonstrated the mechanism of an active tractor beam for multiple fully immersed objects with additional abilities to yielding stable long distance levitation, a controlled rotation and a desired 3D trapping. This is demonstrated with a single optical setup by using two coaxial, or even non-coaxial, superimposed higher order monochromatic Bessel beams of reverse helical nature and different frequencies. The superimposed beams can possess periodic intensity variations both along and around the beam-axis due to a difference in longitudinal wave-numbers and beam orders, respectively. The difference in frequencies of the two laser beams makes the intensity pattern to move along and around the beam-axis in a continuous way without manual ramping of phase, which allows for bidirectional movement of completely immersed multiple particles. The condition for increasing or decreasing the dimension of binding regions is also proposed here to manipulate multiple immersed objects of different sizes under dipole approximation.

Steel fibers and their aspect ratios are important parameters that have significant influence on the mechanical properties of ultrahigh-performance fiber-reinforced concrete (UHPFRC). Steel fiber dosage also significantly contributes to the initial manufacturing cost of UHPFRC. This study presents a comprehensive literature review of the effects of steel fiber percentages and aspect ratios on the setting time, workability, and mechanical properties of UHPFRC. It was evident that (1) an increase in steel fiber dosage and aspect ratio negatively impacted workability, owing to the interlocking between fibers; (2) compressive strength was positively influenced by the steel fiber dosage and aspect ratio; and (3) a faster loading rate significantly improved the mechanical properties. There were also some shortcomings in the measurement method for setting time. Lastly, this research highlights current issues for future research. The findings of the study are useful for practicing engineers to understand the distinctive characteristics of UHPFRC.

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