MICROEMULSIONS: PLATFORM FOR IMPROVEMENT OF SOLUBILITY AND DISSOLUTION OF POORLY SOLUBLE DRUGS

ABSTRACTThis study reviews that solubilization of lipophilic drugs with low aqueous solubility has been a major trust area in recent years. It can be seen thatthere is a real and continuing need for the development of effective drug delivery systems for poorly water-soluble drugs to enhance their absorptionand bioavailability. One such approach might be pharmaceutical microemulsions as they have emerged as potential solubility enhancing technologies.Microemulsion system has considerable potential to act as a drug delivery vehicle by incorporating a wide range of drug molecules. Microemulsionhas got advantage like excellent thermodynamic stability, high drug solubilization capacity, improved oral bioavailability and protection againstenzymatic hydrolysis. This review focuses on the basic concept, formulation, characterization, and recent advances in microemulsions as novel drugdelivery system.Keywords: Microemulsion, Lipophilicity, Solubilization, Bioavailability, Phase behavior

Relativistic calculations of the lifetimes and hyperfine structure constants in 67^{67}Zn+^{+}

This work presents accurate {\it ab initio} determination of the magnetic dipole (M1) and electric quadrupole (E2) hyperfine structure constants for the ground and a few low-lying excited states in $^{67}$Zn$^{+}$, which is one of the interesting systems in fundamental physics. The coupled-cluster (CC) theory within the relativistic framework has been used here in this calculations. Long standing demands for a relativistic and highly correlated calculations like CC can be able to resolve the disagreements among the lifetime estimations reported previously for a few low-lying states of Zn$^{+}$. The role of different electron correlation effects in the determination of these quantities are discussed and their contributions are presented.Comment: 9 pages, 1 figure. submitted to J. Phys. B Fast Trac

RGS Proteins and Septins Cooperate to Promote Chemotropism by Regulating Polar Cap Mobility

Background—Septins are well known to form a boundary between mother and daughter cells in mitosis, but their role in other morphogenic states is poorly understood. Results—Using microfluidics and live cell microscopy, coupled with new computational methods for image analysis, we investigated septin function during pheromone-dependent chemotropic growth in yeast. We show that septins colocalize with the regulator of G-protein signaling (RGS) Sst2, a GTPase-activating protein that dampens pheromone receptor signaling. We show further that the septin structure surrounds the polar cap, ensuring that cell growth is directed toward the source of pheromone. When RGS activity is abrogated, septins are partially disorganized. Under these circumstances the polar cap travels toward septin structures and away from sites of exocytosis, resulting in a loss of gradient tracking. Conclusion—Septin organization is dependent on RGS protein activity. When assembled correctly, septins promote turning of the polar cap and proper tracking of a pheromone gradient

Competitive selection, trade, and employment:The strategic use of subsidies

We thank Holger Görg, Philipp Schröder, Fredrik Sjöholm, participants at the Danish International Economics Workshop, seminar participants at Aberdeen, Sheffield and Loughborough, three anonymous referees and the Editor of the journal, for helpful comments and suggestions. Funding from the European Union’s Seventh Framework Programme for research, technological development and demonstration under grant agreement no 290647 is gratefully acknowledged.Peer reviewedPostprin

How Efficient Is The Langacker-Pi Mechanism of Monopole Annihilation?

We investigate the dynamics of monopole annihilation by the Langacker-Pi mechanism. We find taht considerations of causality, flux-tube energetics and the friction from Aharonov-Bohm scatteering suggest that the monopole annihilation is most efficient if electromagnetism is spontaneously broken at the lowest temperature ($T_{em} \approx 10^6 GeV$) consistent with not having the monopoles dominate the energy density of the universe.Comment: 10 page

Viscosity solutions of systems of PDEs with interconnected obstacles and Multi modes switching problems

This paper deals with existence and uniqueness, in viscosity sense, of a solution for a system of m variational partial differential inequalities with inter-connected obstacles. A particular case of this system is the deterministic version of the Verification Theorem of the Markovian optimal m-states switching problem. The switching cost functions are arbitrary. This problem is connected with the valuation of a power plant in the energy market. The main tool is the notion of systems of reflected BSDEs with oblique reflection.Comment: 36 page

Corporate Hierarchies and the Size of Nations: Theory and Evidence

Corporate organization varies within a country and across countries with country size. The paper starts by establishing some facts about corporate organization based on unique data of 660 Austrian and German corporations. The larger country (Germany) has larger firms with flatter more decentral corporate hierarchies compared to the smaller country (Austria). Firms in the larger country change their organization less fast than firms in the smaller country. Over time firms have been introducing less hierarchical organizations by delegating power to lower levels of the corporation. We develop a theory which explains these facts and which links these features to the trade environment that countries and firms face. We introduce firms with internal hierarchies in a Krugman (1980) model of trade. We show that international trade and the toughness of competition in international markets induce a power struggle in firms which eventually leads to decentralized corporate hierarchies. We offer econometric evidence which is consistent with the models predictions

Improved crop productivity and rural livelihoods through balanced nutrition in the rainfed semi-arid tropics

Diagnostic soil analysis in targeted clusters of eight districts in Andhra Pradesh revealed critical deficiencies of sulphur (61 to 98%), boron (23 to 98%) and zinc (45 to 85%) in addition to that of soil carbon (25 to 97%), and phosphorus (14 to 84%) which are apparently holding back the productivity potential. The soil test based application of sulphur, boron and zinc together increased productivity by 8 to 102% in cotton, groundnut, castor, sorghum, greengram, cowpea, chickpea and maize. Economic assessment reveal that per rupee invested as additional cost (` 1,400/- to ` 2,150/-) gave ` 1.6 to 28.5 in return. Residual benefits of balanced nutrition were observed during 4 succeeding seasons. Soil health improved in balanced nutrition plots, inspite of higher yields and nutrient removal. The results showed that balanced nutrition is the way forward to increase crop productivity through resilience building of production systems and improve farm based livelihoods in the SAT regions

Correlation Effect on Peierls Transition

The effect of correlation on Peierls transition, which is accompanied by a dimerization, t_d, of a bond alternation for transfer energy, has been examined for a half-filled one-dimensional electron system with on-site repulsive interaction (U). By applying the renormalization group method to the interaction of the bosonized Hamiltonian, the dimerization has been calculated variationally and self-consistently with a fixed electron-phonon coupling constant (\lambda) and it is shown that t_d takes a maximum as a function of U. The result is examined in terms of charge gap and spin gap and is compared with that of the numerical simulation by Hirsch [Phys. Rev. Lett 51 (1983) 296]. Relevance to the spin Peierls transition in organic conductors is discussed.Comment: 4 pages, 4 figures, to be published in J. Phys. Soc. Jpn. 71 No.3 (2002