Interferometry-based modal analysis with finite aperture effects

We analyze the effects of aperture finiteness on interferograms recorded to unveil the modal content of optical beams in arbitrary basis using generalized interferometry. We develop a scheme for modal reconstruction from interferometric measurements that accounts for the ensuing clipping effects. Clipping-cognizant reconstruction is shown to yield significant performance gains over traditional schemes that overlook such effects that do arise in practice. Our work can inspire further research on reconstruction schemes and algorithms that account for practical hardware limitations in a variety of contexts

Compressive optical interferometry

Compressive sensing (CS) combines data acquisition with compression coding to reduce the number of measurements required to reconstruct a sparse signal. In optics, this usually takes the form of projecting the field onto sequences of random spatial patterns that are selected from an appropriate random ensemble. We show here that CS can be exploited in `native' optics hardware without introducing added components. Specifically, we show that random sub-Nyquist sampling of an interferogram helps reconstruct the field modal structure. The distribution of reduced sensing matrices corresponding to random measurements is provably incoherent and isotropic, which helps us carry out CS successfully

Culture and molecular characterization of phages isolated from rainbow trout farms and sewage treatment plants and investigation of their effects on Yersinia ruckeri

In the present study bacteriophages isolated from rainbow trout farms and sewage treatment plants were genetically identified and their effectiveness on Yersinia ruckeri isolates from clinical cases of red mouth disease was investigated. Fish samples suspected to red mouth disease were collected from rainbow trout farms located in west Azerbaijan. Y. ruckeri, the causative agent of red mouth disease was initially identified using biochemical tests. The biotypes of all Y. ruckeri isolates were determined and their identity was confirmed by employing genus specific primers. Antimicrobial resistance of Y. ruckeri isolates were examined using common antibiotics in use in aquaculture. In order to isolating lytic bacteriophages, environmental samples mainly from rainbow trout farms and sewage treatment plants were collected in a period of six months. Isolated bacteriophages were titrated using two-layer agar method and their bactericidal effects were examined. For molecular characterization of bacteriophages, genomic DNA was extracted. Extracted genomic DNA from bacteriophages was digested using MspI endonuclease. The results revealed that 4.48% of examined fish were positive for Y. ruckeri. Bacteriophages isolated from urban sewage treatment plants were effective on Y. ruckeri isolates. Maragheh and Urmia sewage treatment plants had the maximum and minimum phage titers, respectively. The genomic DNA of all isolated phages were smaller than genomic DNA of Lambda phage and all examined phages showed similar genomic DNA digestion patterns. It was concluded that sewage treatment plants could be an important source for phages effective on Y. ruckeri and maybe other aquaculture bacterial pathogens

Allelic polymorphism of 'Makoei' sheep myostatin gene identified by polymerase chain reaction and single strand conformation polymorphism

Myostatin, a transforming growth factor-beta (TGF-) super family member, has been well documented as a negative regulator of muscle growth and development. Myostatin with 376 amino acids is synthesized as a precursor protein. In this study, polymorphism of myostatin gene in Iranian 'Makoei' sheep breeds was investigated by polymerase chain reaction and single strand conformation polymorphism technique (PCR–SSCP). Genomic DNA was isolated from the blood of 92 sheep. A 417 bp myostatin intron 1 segment was amplified by standard PCR, using the locus specific primers. Four different SSCP patterns, representing four different genotypes, were identified. The frequencies of the observed genotypes were , 0.293, 0.130, and 0.163 for AD, AC, AE, and BC, respectively. Allele frequencies were 0.4185, 0.0815, 0.2283, 0.2065 and 0.0652 for A, B, C, D and E. Observed heterozygosity (Hobs) value was 0.7192. The chi-square test showed significant (P<0.05) deviation from Hardy-Weinberg equilibrium for this locus in studied population.Key words: Myostatin gene, polymerase chain reaction (PCR), single strand conformation polymorphism technique (SSCP), Ovis aries

Combined efficacy of silver nanoparticles and commercial antibiotics on different phylogenetic groups of Escherichia coli

NO ABSTRACT AVAILABLESilver nanoparticles (Ag-NPs) can attach to flexible polymeric chains of antibiotics, hence it can be used in combination with antibiotics against resistant bacteria. In this study, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and MBC/MIC ratio of Ag-NPs and antibiotics (gentamicin, tetracycline, erythromycin, ciprofloxacin, nalidixic acid, cefixime, cephalexin, amoxicillin, ampicillin, and penicillin) were quantified against 50 Escherichia coli isolates (25 human urinary tract infection and 25 avian colibacillosis). All isolates had been assigned as four phylogenetic groups A, B1, B2, and D. The results showed that the majority of the human and broiler isolates belonged to phylogenetic groups A and B2. MBC/MIC ratio of Ag-NPs in combination with antibiotics was assessed. It was found that the MIC of the majority of broiler isolates to Ag-NPs was equal to or greater than 50 μg/ml. To conclude, a combination of penicillin and ciprofloxacin with Ag-NPs exhibited profound impact against isolates, the combinations might be applicable for treating multidrug-resistant bacteria

Molecular identification and phylogenetic analysis of Lactobacillus and Bifidobacterium spp. isolated from gut of honeybees (Apis mellifera) from West Azerbaijan, Iran

Available online: 15 December 2016Polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) and phylogenetic analysis were used for molecular identification of lactic acid bacteria (LABs) isolated from Apis mellifera. Eighteen honeybee workers were collected from three different apiaries in West Azerbaijan. LABs from the gut of honeybees were isolated and cultured using routine biochemical procedures. Genomic DNA was extracted from LABs and a fragment of 1540 bp in size of 16S rRNA gene was amplified. PCR products were digested using HinfI endonuclease and digested products with different RFLP patterns were subjected to nucleotide sequencing and phylogenetic analysis. The results revealed that Lactobacillus and Bifidobacteria spp. are were the most abundant LABs in honeybee gut. Phylogenetic analysis showed that both Lactobacillus and Bifidobacterium were closely clustered with high similarity percentage with the same bacteria isolated from honeybees’ gut elsewhere. It was concluded that LABs isolated from honeybees had low sequence divergence in comparison with LABs isolated from other sources such as dairy products.Mohammad Farouq Sharifpour, Karim Mardani, Abdulghaffar Ownag

PCR-RFLP detection of Haemoproteus spp. (Haemosporida: Haemoproteidae) in pigeon blood samples from Iran

This study was carried out to determine Haemoproteus spp. infection in pigeons in Iran. Blood sam-ples collected from pigeons were examined for Haemoproteus spp. using stained blood smears and polymerase chain reaction (PCR). For PCR, DNA was extracted from blood samples and a fragment of 617 bp in size subjected to PCR using HAEMF and HAEMR2 derived from cytochrome b gene of the parasite mitochondrial genome. A total number of 93 blood samples from pigeons were examined for Haemoproteus spp. of which 13 (13.97%) samples were positive in stained blood smears for Haemoproteus spp. and 27 (24.73%) were positive in PCR. Digestion of PCR product with AluI re-striction endonuclease generated only one distinct pattern for all positive samples, which is indicative of identical Haemoproteus spp. presence in infected pigeons. The results also revealed that PCR had higher sensitivity in detecting Haemoproteus spp. in pigeons

What is the maximum differential group delay achievable by a space-time wave packet in free space?

The group velocity of 'space-time' wave packets $-$ propagation-invariant pulsed beams endowed with tight spatio-temporal spectral correlations $-$ can take on arbitrary values in free space. Here we investigate theoretically and experimentally the maximum achievable group delay that realistic finite-energy space-time wave packets can achieve with respect to a reference pulse traveling at the speed of light. We find that this delay is determined solely by the spectral uncertainty in the association between the spatial frequencies and wavelengths underlying the wave packet spatio-temporal spectrum $-$ and not by the beam size, bandwidth, or pulse width. We show experimentally that the propagation of space-time wave packets is delimited by a spectral-uncertainty-induced `pilot envelope' that travels at a group velocity equal to the speed of light in vacuum. Temporal walk-off between the space-time wave packet and the pilot envelope limits the maximum achievable differential group delay to the width of the pilot envelope. Within this pilot envelope, the space-time wave packet can locally travel at an arbitrary group velocity and yet not violate relativistic causality because the leading or trailing edge of superluminal and subluminal space-time wave packets, respectively, are suppressed once they reach the envelope edge. Using pulses of width $\sim$4ps and a spectral uncertainty of $\sim$ 20 pm, we measure maximum differential group delays of approximately $\pm$ 150 ps, which exceed previously reported measurements by at least three orders of magnitude