Aharonov-Bohm Radiation of Fermions

We analyze Aharonov-Bohm radiation of charged fermions from oscillating solenoids and cosmic strings. We find that the angular pattern of the radiation has features that differ significantly from that for bosons. For example, fermionic radiation in the lowest harmonic is approximately isotropically distributed around an oscillating solenoid, whereas for bosons the radiation is dipolar. We also investigate the spin polarization of the emitted fermion-antifermion pair. Fermionic radiation from kinks and cusps on cosmic strings is shown to depend linearly on the ultraviolet cut-off, suggesting strong emission at an energy scale comparable to the string energy scale.Comment: 14 pages, 6 figures. Version 2: Expanded discussion on boundary conditions obeyed by Dirac equation mode functions (in Section V B). Acknowledgements and references added. Version 3: Minor changes made in response to referee's comment

A Nearly Scale Invariant Spectrum of Gravitational Radiation from Global Phase Transitions

Using a large N sigma model approximation we explicitly calculate the power spectrum of gravitational waves arising from a global phase transition in the early universe and we confirm that it is scale invariant, implying an observation of such a spectrum may not be a unique feature of inflation. Moreover, the predicted amplitude can be over 3 orders of magnitude larger than the naive dimensional estimate, implying that even a transition that occurs after inflation may dominate in Cosmic Microwave Background polarization or other gravity wave signals.Comment: 4 pages, PRL published versio

A New Class of non-Hermitian Quantum Hamiltonians with PT Symmetry

In a remarkable development Bender and coworkers have shown that it is possible to formulate quantum mechanics consistently even if the Hamiltonian and other observables are not Hermitian. Their formulation, dubbed PT quantum mechanics, replaces hermiticity by another set of requirements, notably that the Hamiltonian should be invariant under the discrete symmetry PT, where P denotes parity and T denotes time reversal. All prior work has focused on the case that time reversal is even (T^2 = 1). We generalize the formalism to the case of odd time reversal (T^2 = -1). We discover an analogue of Kramer's theorem for PT quantum mechanics, present a prototypical example of a PT quantum system with odd time reversal, and discuss potential applications of the formalism. Odd time reversal symmetry applies to fermionic systems including quarks and leptons and a plethora of models in nuclear, atomic and condensed matter physics. PT quantum mechanics makes it possible to enlarge the set of possible Hamiltonians that physicists could deploy to describe fundamental physics beyond the standard model or for the effective description of condensed matter phenomena.Comment: Replaced submitted version with accepted version; to appear in Phys Rev

Zero modes on cosmic strings in an external magnetic field

A classical analysis suggests that an external magnetic field can cause trajectories of charge carriers on a superconducting domain wall or cosmic string to bend, thus expelling charge carriers with energy above the mass threshold into the bulk. We study this process by solving the Dirac equation for a fermion of mass $m_f$ and charge $e$, in the background of a domain wall and a magnetic field of strength $B$. We find that the modes of the charge carriers get shifted into the bulk, in agreement with classical expectations. However the dispersion relation for the zero modes changes dramatically -- instead of the usual linear dispersion relation, $\omega_k =k$, the new dispersion relation is well fit by $\omega \approx m_f tanh(k/k_*)$ where $k_*=m_f$ for a thin wall in the weak field limit, and $k_*=eBw$ for a thick wall of width $w$. This result shows that the energy of the charge carriers on the domain wall remains below the threshold for expulsion even in the presence of an external magnetic field. If charge carriers are expelled due to an additional perturbation, they are most likely to be ejected at the threshold energy $\sim m_f$.Comment: 9 pages, 4 figure

Study of drug utilization, morbidity pattern and cost of hypolipidemic agents in a tertiary care hospital

Background: Data on the extent of use and costs of lipid-lowering agents are not widely available. Our aim was to study the drug utilization and morbidity pattern, cost of different hypolipidemic drugs along with the risk assessment for coronary heart disease.Methods: After approval of protocol by the Institutional Review Board, an observational, prospective study was carried out in 300 patients using NCEP and ATP III Guidelines-2002 for evaluation of presence or absence of risk factors for coronary heart diseases. Data were analysed using SPSS software version 16.0and WHO Core Drug Prescribing Indicators.Results: Patient’s morbidity pattern revealed that 62%, 49.3%, 28% suffered from ischemic heart disease, hypertension and type 2 diabetes mellitus respectively. On risk assessment, 48%, 13.3% patients had borderline and high level of total cholesterol respectively; 42%, 22.7% had borderline and high triglyceride levels respectively; 71.1% men and 62% women had low HDL cholesterol levels while 17.3%, 6% and 2.7% patients had borderline high, high and very high level of LDL cholesterol levels respectively. Frequency of prescriptions was atorvastatin (82%), rosuvastatin (9.3%) and simvastatin (4.7%) among the most frequently prescribed statins drug group. The mean number of drugs per prescription was 7.34. Drugs prescribed by generic name and from essential drugs list was 24.96% and 71.81% respectively. Mean cost of hypolipidemic agents/prescription/day was 10.74 (±1.96) Indian Rupees with rosuvastatin being the costliest.Conclusion: Rational use of hypolipidemic agents with an increasing trend of statins prescriptions will significantly reduce the morbidity and mortality from coronary heart diseases.

STUDY OF BINDING INTERACTIONS OF HUMAN CARBONIC ANHYDRASE XII

Objective: The present study was carried out to study the binding interactions of different N'-(substituted phenyl sulfonyl)-pyridine-2-carbohydrazide derivatives and N'-(substituted phenyl sulfonyl)-thiophene-2-carbohydrazide derivatives which were synthesized by senior students from research laboratory, with objective to explore the suitability of selected ligands for their binding affinity for the selected target.Methods: Binding interactions of the selected ligands were studied using glide module of Schrodinger software using Maestro 10.1 interface. At the end of molecular docking studies, docking scores along with 2D and 3D binding interactions of these ligands were studied to evaluate the potency of ligands to act as selective human carbonic anhydrase (hCAXII) inhibitors in comparison with standard inhibitor Acetazolamide (AZA).Results: Docking study on the ligands exhibited very similar conformation and binding interactions with hCAXII as that of standard. This suggests that selected ligands might possess significant binding affinity for hCAXII.Conclusion: It can be concluded that the selected ligands have the potential to act as inhibitors of hCAXII

A study of morbidity and drug utilization pattern in indoor patients of high risk pregnancy at tertiary care hospital

Background: Pregnancy represents a special physiological state during which the use of drug is of growing concern due to risk of teratogenicity. High risk pregnancy is common threat to mother and foetus. Therefore, our aim was to study the drug utilization and morbidity pattern in high risk pregnancy in hospitalized pregnant women. Methods:An observational, prospective study was carried out in 250 patients for 6 months in the tertiary care hospital. Protocol was approved by the Institutional Review Board (IRB). The data were collected in a pre-designed proforma. Data were analysed by using SPSS version 20.0 Software. Results: Among 250 patients, 19 (7.6%), 218 (87.2%) and 13 (5.2%) were of less than 20, 20 to 30 and more than 30 years of age respectively. About 68.8% women had complained of abdominal pain and 67.6% had weakness followed by headache / body ache (47.2%), oedema (26.4%) and vomiting (18.8%). Iron (91.2%) and calcium (84.5%) were the commonest drugs prescribed followed by folic acid (59.6%), protein powder (54.8%), vitamin C (46.8%) and isoxsuprine (26.6%). As per FDA Drug Risk Category, Category-A (82.21%) was most frequently prescribed followed by Category-B (15.64%) and Category-C (2.15%). Percentage of drugs prescribed by generic name and from essential drug list was 62.80% and 80.79%. Conclusion: Iron, Calcium and Folic acid were most commonly prescribed drugs. There is lesser number of drugs prescribed by generic name suggesting need for sincere efforts to improve situation