Quantum Chaos of a particle in a square well : Competing Length Scales and Dynamical Localization

The classical and quantum dynamics of a particle trapped in a one-dimensional infinite square well with a time periodic pulsed field is investigated. This is a two-parameter non-KAM generalization of the kicked rotor, which can be seen as the standard map of particles subjected to both smooth and hard potentials. The virtue of the generalization lies in the introduction of an extra parameter R which is the ratio of two length scales, namely the well width and the field wavelength. If R is a non-integer the dynamics is discontinuous and non-KAM. We have explored the role of R in controlling the localization properties of the eigenstates. In particular the connection between classical diffusion and localization is found to generalize reasonably well. In unbounded chaotic systems such as these, while the nearest neighbour spacing distribution of the eigenvalues is less sensitive to the nature of the classical dynamics, the distribution of participation ratios of the eigenstates proves to be a sensitive measure; in the chaotic regimes the latter being lognormal. We find that the tails of the well converged localized states are exponentially localized despite the discontinuous dynamics while the bulk part shows fluctuations that tend to be closer to Random Matrix Theory predictions. Time evolving states show considerable R dependence and tuning R to enhance classical diffusion can lead to significantly larger quantum diffusion for the same field strengths, an effect that is potentially observable in present day experiments.Comment: 29 pages (including 14 figures). Better quality of Figs. 1,3 & 9 can be obtained from author

Sinteza i farmakološka evaluacija 3-cikloheksil-2-supstituiranih hidrazino-3H-kinazolin-4-ona kao analgetika i antiinflamatorika

A series of novel 3-cyclohexyl-2-substituted hydrazino-quinazolin-4(3H)-ones were synthesized by reacting the amino group of 3-cyclohexyl-2-hydrazino quinazolin-4(3H)-one with a variety of aldehydes and ketones. The starting material, 3-cyclohexyl-2-hydrazino quinazolin-4(3H)-one, was synthesized from cyclohexyl amine. Title compounds were investigated for analgesic, anti-inflammatory and ulcerogenic behavior. The compound 3-cyclohexyl-2-(1-methylbutylidene-hydrazino)-3H-quinazolin-4-one (4c) emerged as the most active compound of the series and is moderately more potent in its analgesic and anti-inflammatory activities compared to the reference standard diclofenac sodium. Interestingly, test compounds showed only mild ulcerogenic potential when compared to acetylsalicylic acid.Reakcijom amino skupine 3-cikloheksil-2-hidrazino kinazolin-4(3H)-ona s različitim aldehidima i ketonima sintetizirani su novi 3-cikloheksil-2-supstituirani hidrazino-kinazolin-4(3H)-oni. Početni spoj 3-cikoheksil-2-hidrazino kinazolin-4(3H)-on pripravljen je iz cikloheksilamina. Sintetizirani spojevi testirani su na analgetsko i protuupalno djelovanje te ulcerogena svojstva. Spoj 3-cikloheksil-2-(1-metilbutiliden-hidrazino)-3H-kinazolin-4-on (4c) imao je najjače analgetsko i protuupalno djelovanje, nešto jače nego referentni spoj diklofenak natrij. Osim toga, testirani spojevi imaju samo blago ulcerogeno djelovanje u usporedbi s acetilsalicilnom kiselinom

Algebraic approach in the study of time-dependent nonlinear integrable systems: Case of the singular oscillator

The classical and the quantal problem of a particle interacting in one-dimension with an external time-dependent quadratic potential and a constant inverse square potential is studied from the Lie-algebraic point of view. The integrability of this system is established by evaluating the exact invariant closely related to the Lewis and Riesenfeld invariant for the time-dependent harmonic oscillator. We study extensively the special and interesting case of a kicked quadratic potential from which we derive a new integrable, nonlinear, area preserving, two-dimensional map which may, for instance, be used in numerical algorithms that integrate the Calogero-Sutherland-Moser Hamiltonian. The dynamics, both classical and quantal, is studied via the time-evolution operator which we evaluate using a recent method of integrating the quantum Liouville-Bloch equations \cite{rau}. The results show the exact one-to-one correspondence between the classical and the quantal dynamics. Our analysis also sheds light on the connection between properties of the SU(1,1) algebra and that of simple dynamical systems.Comment: 17 pages, 4 figures, Accepted in PR

INTERNATIONAL JOURNAL OF PHARMACY & LIFE SCIENCES Formulation and evaluation of aceclofenac fast dissolving tablets

Abstract The present investigation deals with development of fast dissolving tablets of aceclofenac to produce the intended benefits. Fast dissolving tablets of aceclofenac were prepared using superdisintegrants crospovidone, croscarmellose sodium and sodium starch glycolate and surfactant sodium lauryl sulfate, using the direct compression method. The tablets prepared were evaluated for thickness, uniformity of weight, hardness, friab ility, wetting time, in vitro disintegration time and in vitro dissolution time. The tablets disintegrated within 18 to 49 seconds. Almost 90% of drug was released from all formulat ions within 15 min. Stability studies of the tablets at 40±2°/75%±5% RH for 3 months showed non significant drug loss. The formulation containing 6% of croscarmellose sodium was found to give the best results. Apart from fulfilling all official and other specifications, the tablets exhib ited higher rate of release

Does a nanomolecule of carboplatin injected periocularly help in attaining higher intravitreal concentrations?

PURPOSE. To compare intravitreal concentration (VC) of commercially available carboplatin (CAC) and the novel nanomolecule carboplatin (NMC), after periocular injection. METHODS. The study was a comparative animal study involving 24 white Sprague-Dawley rats, aged between 6 weeks and 3 months. CAC was bound with a nanoparticulate carrier by co-acervation with a biocompatible and biodegradable protein BSA (bovine serum albumin). The particulate size, binding, and structure of the carrier was analyzed with dynamic light-scattering electron microscopy, FTIR (Fourier transform infrared) spectroscopy, and SDS-polyacrylamide gel electrophoresis. Twenty-four white rats were anesthetized. The right eye of each rat was injected with periocular CAC (1 mL) and the left eye with NMC (1 mL) by a trained ophthalmologist. Four mice each were euthanatized at days 1, 2, 3, 5, 7, 14, and 21 and both eyes were enucleated. The intravitreal concentrations of commercial carboplatin and nanomolecule carboplatin were determined with HPLC (high-performance liquid chromatography). Data were analyzed with the paired t-test. The main outcome measure was intravitreal concentrations CAC and NMC over time. RESULTS. The NMC vitreal concentration was higher than the CAC concentrations in all animals, until day 7 (P = 0.0001). On days 14 and 21, the CAC vitreal concentration was higher than the NMC concentrations in all animals (P = 0.0002). Overall, the mean vitreal concentration of NMC was greater than CAC. CONCLUSIONS. Nanoparticulate-bound carboplatin has greater transscleral transport than commercially available carboplatin, especially in the first week after injection and may help enhance the proven adjuvant efficacy of periocular carboplatin over and above systemic chemotherapy in treating human retinoblastoma, especially those with vitreal seeds. This trial is being published to establish a proof of principle for this method of therapy. (Invest Ophthalmol Vis Sci. 2009;50:5896-5900) DOI:10.1167/iovs.09-391