Buccal Drug Delivery: Past, Present and Future – A Review

The major hindrance for the absorption of a drug taken orally is extensive first pass metabolism or stability problems within the GI environment like instability in gastric pH and complexation with mucosal membrane. These obstacles can be overcome by altering the route of administration as parenteral, transdermal or trasmucosal. Among these trasmucosal has the advantage of ease of administration, patient compliance and are economic too. The mucosa of the buccal cavity is the most easily accessible transmuocosal site. Buccal transmucosal delivery helps to bypass first- pass metabolism by allowing direct access to the systemic circulation through the internal jugular vein. The buccal transmucosal route has been researched for a wide variety of drugs. Several methodologies have been considered so far, to design and manipulate the release properties towards the invention of buccal mucosal delivery systems. This article aims at reviewing the numerous techniques that has been designed till date for optimizing buccal transmucosal drug delivery.Keywords: complexation; parenteral; transdermal; trasmucosa

Influence of dissipative entry temperature on laminar heat transfer in thermally developing region of a circular pipe with viscous dissipation

Paper presented at the 8th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Mauritius, 11-13 July, 2011.Steady laminar forced convection heat transfer in the thermal entrance region of a circular pipe including viscous dissipation has been studied assuming the flow to be hydrodynamically fully developed and thermally developing. The circular pipe is subjected to constant wall temperature. Two entry temperatures have been considered. 1) A temperature that varies with the radial coordinate obtained in an adiabatic pipe due to viscous dissipation while the flow is hydrodynamically developing. This temperature is termed as the dissipative entry temperature. 2) A uniform temperature equal to the bulk mean value of the dissipative entry temperature. It has been shown that the difference in the Nusselt numbers and heat transfer obtained with these two entry temperatures is insignificant. Thus, the simplicity of classical assumption of uniform entry temperature can be retained when the entry temperature has been chosen as the bulk mean of the dissipative entry temperature.mp201

The nil Hecke ring and singularity of Schubert varieties

We give a criterion for smoothness of a point in any Schubert variety in any G/B in terms of the nil Hecke ring.Comment: AMSTE

Crack avalanches in the three dimensional random fuse model

We analyze the scaling of avalanche precursors in the three dimensional random fuse model by numerical simulations. We find that both the integrated and non-integrated avalanche size distributions are in good agreement with the results of the global load sharing fiber bundle model, which represents the mean-field limit of the model.Comment: 6 pages, 2 figures, submitted for the proceedings of the conference "Physics Survey of Irregular Systems", in honor of Bernard Sapova

Improved Non-Isolated Bidirectional DC-DC Converter Assisted with an Active Resonant Network

OP VVV Electrical Engineering Technologies with High-Level of Embedded Intelligence CZ.02.1.01/0.0/0.0/18_069/0009855 and project No. SGS-2021-021This paper proposes a new non-isolated bidirectional dc-dc converter (NI-BDC) with an auxiliary resonant network (ARN) that is typically operated in both boost and buck modes. Regardless the direction of power flow, soft-switching capabilities such as zero voltage switching (ZVS) and zero current switching (ZCS) conditions has been obtained under light and heavy loads. This converter avoids the need of coupled inductors as against conventional converters thus reducing the size of the converter and minimizes the device count. The auxiliary resonant network mainly consisting of resonant inductor, capacitor, auxiliary switch and a diode. Furthermore, the zero voltage switching and zero current switching conditions have been achieved in both boost and buck modes that reduces reverse recovery conduction period of the body diodes of all the power switches. The proposed converter operates with soft-switching at constant switching frequency giving continuous inductor current. The detailed operating principles for boost and buck modes are described. The theoretical analysis and simulation results are presented

Effect of Lanthanum Substitution on the Structural, dielectric, Ferroelectric and Piezoelectric Properties of Mechanically Activated PZt Electroceramics

Different compositions of (Pb1-xLax) (Zr0.60Ti0.40)O3 (abbreviated as PLZT x/60/40; x=0, 0.07, 0.08 and 0.10) ceramics were prepared by a combinatorial approach by high energy mechano-chemical ball milling and cold isostatic pressing (CIP). X-ray diffraction patterns and transmission as well as scanning electron microscope were used for the micro-structural and morphological studies. The average particle size of PLZT milled powders was measured from the TEM images and was found to be in the nm range.XRD patterns of the sintered PLZT x/60/40 ceramics confirm the perovskite phase formation after heat treatment. SEM of sintered PLZT x/60/40 ceramics show a close packed dense structure. PLZT 8/60/40 ceramics show the fine grains (~1.3 µm) with density ~97 per cent. Dielectric constant and loss were measured as a function of temperature. PLZT 8/60/40 ceramics shows the highest value of room temperature dielectric constant ~2480 at 1 kHz. Ferroelectric studies were done with the help of polarisation (P-E) and strain (S-E) vs. electric field measurements. PLZT 8/60/40 ceramics shows the maximum value of remnant polarisation (~36 µC/cm2) and strain (~0.27 per cent), respectively. PLZT x/60/40 ceramic samples were poled at optimized poling conditions. The measured values of piezoelectric charge coefficient (d33) and electromechanical coupling factor (kp) of PLZT 8/60/40 ceramics were found to be, ~690 pC/N and ~71 per cent, respectively

Numerical Investigation of the Shock Train in a Scramjet with the Effects of Back-Pressure and Divergent Angles

Numerical simulations are carried out to study the effect of divergence angle and adverse pressure gradient on the movement of shock wave train in a scramjet isolator. The commercial software tool ANSYS Fluent 16 was used to simplify two dimensional Reynolds averaged Navier Stokes equation with compressible fluid flow by considering the density-based solver with standard K-ε turbulence model. The species transport model with single step volumetric reaction mechanism is employed. Initially, the simulated results are validated with experimental results available in open literature. The obtained results show that the variation of the divergence angle and back pressure on the scramjet isolator has greater significance on the flow field. Also, with an increase in the back pressure, due to the intense turbulent combustion, the shock wave train developed should expand along the length and also moves towards the leading edge of the isolator leading to rapid rise in the pressure so that the pressure at the entrance of the isolator can match the enhanced back pressures

Efficiency Improvement Of An Electrical Transformer By Design Development Of FINS

A transformer is an electrical gadget that exchanges electrical energy between two or more circuits through electromagnetic affectation. Normally, transformers are utilized to increment or diminish the voltages of exchanging current in electric force applications; a differing current in the transformer's essential winding makes a changing attractive flux in the transformer center and a shifting attractive field impinging on the transformer's auxiliary winding. This fluctuating attractive field at the auxiliary winding affects a shifting electromotive power (EMF) or voltage in the optional winding. Making utilization of Faraday's Law in conjunction with high attractive porousness center properties, transformers can along these lines be intended to proficiently change AC voltages starting with one voltage level then onto  another within power networks.   Copper losses are resistive and proportional to load current and are sometimes called “load losses”, as the transformer is loaded; heat is produced in the primary and secondary windings and connections due to losses. At low loads, the quantity of heat produced will be small but as load increases, the amount of heat produced becomes significant at full load, the windings will be operating at or near their design temperature, Figure shows the relationship between load-current and the heat produced in transformer windings and connections. If the ambient temperature is too high then the transformer will automatically fail to work , even though some coolants are employed in the transformers to carry away the heat, they are not enough during summer seasons so there is a need to develop better cooling systems In this project we develop better cooling system for a transformer using 3D modelling and Finite Element Methods so that the transformers will work without fail. For 3D modelling we use Catia V5 R20 and for finite element analysis we use Ansys 15.

Multiwavelength Study on Solar and Interplanetary Origins of the Strongest Geomagnetic Storm of Solar Cycle 23

We study the solar sources of an intense geomagnetic storm of solar cycle 23 that occurred on 20 November 2003, based on ground- and space-based multiwavelength observations. The coronal mass ejections (CMEs) responsible for the above geomagnetic storm originated from the super-active region NOAA 10501. We investigate the H-alpha observations of the flare events made with a 15 cm solar tower telescope at ARIES, Nainital, India. The propagation characteristics of the CMEs have been derived from the three-dimensional images of the solar wind (i.e., density and speed) obtained from the interplanetary scintillation data, supplemented with other ground- and space-based measurements. The TRACE, SXI and H-alpha observations revealed two successive ejections (of speeds ~350 and ~100 km/s), originating from the same filament channel, which were associated with two high speed CMEs (~1223 and ~1660 km/s, respectively). These two ejections generated propagating fast shock waves (i.e., fast drifting type II radio bursts) in the corona. The interaction of these CMEs along the Sun-Earth line has led to the severity of the storm. According to our investigation, the interplanetary medium consisted of two merging magnetic clouds (MCs) that preserved their identity during their propagation. These magnetic clouds made the interplanetary magnetic field (IMF) southward for a long time, which reconnected with the geomagnetic field, resulting the super-storm (Dst_peak=-472 nT) on the Earth.Comment: 24 pages, 16 figures, Accepted for publication in Solar Physic

Statistical mechanics of semiflexible ribbon polymers

The statistical mechanics of a ribbon polymer made up of two semiflexible chains is studied using both analytical techniques and simulation. The system is found to have a crossover transition at some finite temperature, from a type of short range order to a fundamentally different sort of short range order. In the high temperature regime, the 2-point correlation functions of the object are identical to worm-like chains, while in the low temperature regime they are different due to a twist structure. The crossover happens when the persistence length of individual strands becomes comparable to the thickness of the ribbon. In the low temperature regime, the ribbon is observed to have a novel ``kink-rod'' structure with a mutual exclusion of twist and bend in contrast to smooth worm-like chain behaviour. This is due to its anisotropic rigidity and corresponds to an {\it infinitely} strong twist-bend coupling. The double-stranded polymer is also studied in a confined geometry. It is shown that when the polymer is restricted in a particular direction to a size less than the bare persistence length of the individual strands, it develops zigzag conformations which are indicated by an oscillatory tangent-tangent correlation function in the direction of confinement. Increasing the separation of the confining plates leads to a crossover to the free behaviour, which takes place at separations close to the bare persistence length. These results are expected to be relevant for experiments which involve complexation of two or more stiff or semiflexible polymers.Comment: 20 pages, 11 figures. PRE (in press