Electro‐optic effects in nematic liquid crystals

Experimental results on the electro-optic effects in nematic liquid crystals are presented. A hexagonal grid pattern is observed with (ac + dc) field at a critical frequency f(c) (168 Hz). The time required for the formation of the grid pattern with applied field is estimated

Effective atomic numbers, electron densities, and tissue equivalence of some gases and mixtures for dosimetry of radiation detectors

Total mass attenuation coefficients, µm, effective atomic number, Zeff, and effective electron density, Neff, of different gases - carbon dioxide, methane, acetylene, propane, butane, and pentane used in radiation detectors, have been calculated for the photon energy of 1 keV to 100 GeV. Each gas has constant Zeff values between 0.10 to 10 MeV photon energies; however, these values are way far away from ICRU tissue. Carbon dioxide gas shows the closest tissue equivalence in the entire photon energy spectrum. Relative tissue equivalences of the mixtures of gases with respect to ICRU tissue are in the range of 0.998-1.041 for air, argon (4.5%) + methane (95.5%), argon (0.5%) + carbon dioxide (99.5%), and nitrogen (5%) + methane (7%) + carbon dioxide (88%). The gas composition of xenon (0.5%) + carbon dioxide (99.5%) shows 1.605 times higher tissue equivalence compared to the ICRU tissue. The investigated photon interaction parameters are useful for exposure and energy absorption buildup factors calculation and design, and fabrication of gaseous detectors for ambient radiation measurement by the Geiger-Muller detector, ionization chambers and proportional counters

Assessment of methods for estimation of effective atomic numbers of common human organ and tissue substitutes: Waxes, plastics and polymers

We calculated mass attenuation coefficients, effective atomic numbers and Kerma relative to air for human organ and tissue substitutes (i.e. wax, plastic and polymer materials). The effective atomic numbers of the tissue substitutes were calculated by the direct method, interpolation method, Auto-Z(eff) software and single value XMuDat program and then compared. The calculated effective atomic numbers were also compared with available experimental data and a good agreement was observed. A large difference in effective atomic numbers calculated by the direct and interpolation methods was observed in photoelectric and pair-production regions. The direct method was found to be appropriate for effective atomic number computation in low-(>10 keV) and medium-(0.1 <= E <= 10 MeV) photon energy regions. Kerma relative to air of the selected tissue substitutes was found to be dependent upon the atomic number and element compositions, which show a sharp peak due to K-edge absorption

Multidrug and extensively drug-resistant tuberculosis from a general practice perspective

Despite intensive efforts to eradicate the disease, tuberculosis continues to be a major threat to Indian society, with an estimated prevalence of 3.45 million cases in 2006. Emergence of multidrug-resistant tuberculosis has complicated eradication attempts in recent years. Incomplete and/inadequate treatment are the main causes for development of drug resistance. Directly observed therapy, short-course (DOTS) is the World Health Organization (WHO) strategy for worldwide eradication of tuberculosis, and our country achieved 100% coverage for DOTS through the Revised National Tuberculosis Control Program in 2006. For patients with multidrug-resistant tuberculosis, the WHO recommends a DOTS-Plus treatment strategy. Early detection and prompt treatment of multidrug-resistant tuberculosis is crucial to avoid spread of the disease and also because of the chances of development of potentially incurable extensively drug-resistant tuberculosis in these cases. This review discusses the epidemiologic, diagnostic, and therapeutic aspects of multidrug-resistant tuberculosis, and also outlines the role of primary care doctors in the management of this dangerous disease

Bilateral hypertrophic olivary nucleus degeneration on magnetic resonance imaging in children with Leigh and Leigh-like syndrome

Objective: Bilateral hypertrophic olivary degeneration on brain MRI has been reported in a few metabolic, genetic and neurodegenerative disorders, including mitochondrial disorders. In this report, we sought to analyse whether bilateral symmetrical inferior olivary nucleus hypertrophy is specifically associated with mitochondrial disorders in children. Methods: This retrospective study included 125 children (mean age, 7.6  &#177;  5 years; male:female, 2.6:1) diagnosed with various metabolic and genetic disorders during 2005–2012. The routine MRI sequences (T1 weighted, T2 weighted and fluid-attenuated inversion–recovery sequences) were analysed for the presence of bilateral symmetrical olivary hypertrophy and central tegmental tract or dentate nuclei signal changes. The other imaging findings and the final diagnoses were noted. Results: The cohort included patients with Leigh and Leigh-like syndrome (n = 25), other mitochondrial diseases (n = 25), Wilson disease (n = 40), Type 1 glutaric aciduria (n = 14), maple syrup urine disease (n = 13), giant axonal neuropathy (n = 5) and L-2 hydroxy glutaric aciduria (n = 3). Bilateral inferior olivary nucleus hypertrophy was noted in 10 patients, all of whom belonged to the Leigh and Leigh-like syndrome group. Conclusion: Bilateral hypertrophic olivary degeneration on MRI is relatively often, but not routinely, seen in children with Leigh and Leigh-like syndrome. Early detection of this finding by radiologists and physicians may facilitate targeted metabolic testing in these children

Identifikacija ptičjih vrsta lančanom reakcijom polimerazom i analizom slijeda mitohondrijskoga gena 12S rRNA

Authentic identification and differentiation of avian species is a vital step in conservative, taxonomic, forensic, legal and other ornithological interventions. The present investigation involved the application of molecular biological approach to identify and differentiate avian species i.e. two species of birds, namely black kite (Milvus migrans) and parakeet (Psittacula krameri). The DNA was isolated from blood samples of each species and a part of the mitochondrial 12S rRNA gene was amplified through polymerase chain reaction (PCR). The PCR products were sequenced and aligned using Basic Local Alignment Search Tool (BLAST) of the GenBank (NCBI). Based on the alignment and similarity/divergence, these avian species were accurately identified and differentiated.Autentična identifikacija i razlikovanje ptičjih vrsta od presudnoga su značenja u različitim konzervirajućim, taksonomskim, sudbenim, zakonskim i drugim ornitološkim aktivnostima. Ovo istraživanje bavi se molekularnobiološkim pristupom identifikaciji i razlikovanja dviju ptičjih vrsta: crvenkaste lunje (sokola) (Milvus migrans) i papige (Psittacula krameri). DNA je bila izdvojena iz uzoraka njihove krvi te je dio mitohondrijskoga 12S rRNA bio umnožen lančanom reakcijom polimerazom. Proizvodi PCR-a bili su sekvencirani i analizirani upotrebom Basic Local Alignment Search Tool (BLAST) genske banke GenBank (NCBI). Na osnovi sličnosti odnosno različitosti nalaza identificirane su te dvije pretraživane vrste