Burning mouth syndrome: a diagnostic and therapeutic dilemma

Burning mouth syndrome (BMS) has been considered an enigmatic condition because the intensity of pain rarely corresponds to the clinical signs of the disease. Various local, systemic and psychological factors are associated with BMS, but its etiology is not fully understood. Also there is no consensus on the diagnosis and classification of BMS. A substantial volume of research has been focused on BMS during the last two decades. Progress has been made but the condition remains a fascinating, yet poorly understood area, in the field of oral medicine. Recently, there has been a resurgence of interest in this disorder with the discovery that the pain of BMS may be neuropathic in origin and originate both centrally and peripherally. The aim of this paper is to explore the condition of BMS with the specific outcome of increasing awareness of the condition

Estimation of serum lipids in patients with Oral Submucous Fibrosis in India

Objectives: Oral submucous fibrosis (OSMF) is the most prevalent precancerous condition in India. Low levels of lipids serves as a marker and prognostic indicator in the early detection of oral precancerous and cancerous states. In spite of the high prevalence and its potential to undergo malignant transformation, this condition has not widely been investigated with respect to the serum lipid levels. In the present study, an attempt was made to analyze the complete serum lipid profile, total cholesterol (TC), triglycerides (TG), high density lipoprotein (HDL) choleste - rol, low density lipoprotein (LDL) cholesterol and very low density lipoprotein (VLDL) cholesterol in OSMF and controls. Material and Methods: The study was conducted in 45 clinically and histopathologically diagnosed cases of OSMF and 45 age and sex matched controls. The complete lipid profile including TC, TG, HDL cholesterol, LDL choles - terol and VLDL cholesterol was analyzed. Results: The serum lipid levels were significantly lower in the patients with OSMF than in the controls. When the values were compared between different disease stages, the maximum reduction of lipids was evident for stage 3 OSMF. From the present results, it is evident that the level of serum lipids decreases with progression of the disea - se. Conclusions: From these findings, it appears that the decrease in the lipid levels may be considered as a useful marker in the early diagnosis of oral premalignant condition like OSMF

Spin-Charge Separation in Two Dimensions - A Numerical Study

The question of spin-charge separation in two-dimensional lattices has been addressed by numerical simulations of the motion of one hole in a half-filled band. The calculations have been performed on finite clusters with Hubbard and t-J models. By comparing the time evolution of spin and charge polarisation currents in one and two dimensions, evidence in favor of spin-charge separation in two dimensions is presented. In contrast with this, spin-charge separation is absent in a highly doped, metallic, system.Comment: RevTeX 3.0, 10 Pages, 6 PostScript Figures (on request

Evolution of surface waviness in thin films via volume and surface diffusion

Deformation mechanisms involving mass transport by stress driven diffusion influence a large number of technological problems. We study the formation of undulations on surfaces of stressed films at high temperature by exploring the deformation kinetics governed by volume and surface diffusion. A governing equation is derived that gives the amplitude change of such surfaces as a function of time. A parametric study is then carried out using a range of practically important input values of the film material properties. The results show that at the dominant instability wavelength, under high average stresses (giga pascal range), only surface diffusion contributes to film surface morphology evolution whereas under low stress and high-temperature conditions, both surface diffusion and volume diffusion contribute to film surface morphology evolution. Furthermore, the contribution of volume diffusion depends on the sign of the film stress, with compressive stress promoting surface roughening and tensile stress promoting surface smoothing.publishedis peer reviewe

Effect of screening on exchange effects for an inhomogeneous electron gas at finite temperatures

Recently, Gupta and Rajagopal [Phys. Rev. A 21, 2064 (1980)] have calculated thermodynamic-exchange energy and potential in an "exchange-only" approximation and later calculated the correlation potential exactly within the random-phase approximation [Phys. Rev. A 22, 2792 (1980)]. In this paper we estimate the effect of screening in an approximate way. The formula obtained for the correlation potential is shown to be the product of two functions, one being that of density and the other being that of dimensionless temperature. The calculated values agree reasonably in the intermediate degeneracy region and are good at higher temperatures and densities. It is shown that the specific heat for the system can also be expressed in terms of the same parameters and the (T/lnT)-type divergence disappears

Specific heat of a two-dimensional electron gas in the exchange approximation

The specific heat of a two-dimensional inhomogeneous electron gas has been calculated using Bardeen's formula in the exchange approximation. High- and low-temperature limits are obtained. The specific heat vanishes inversely with temperature in the high-temperature limit and the expected T in T behaviour is obtained in the low-temperature limit. A universal curve is obtained which gives the specific heat in the exchange approximation for any density and temperature

Exchange and correlation potential for a two-dimensional electron gas at finite temperatures

Calculations for an inhomogeneous electron gas using density-functional theory require suitable exchange and correlation potentials. We present here the local exchange and correlation potential (Vxc) for the two-dimensional electron gas over a wide range of temperatures and densities based upon summation of ring graphs. A suitable parametric fit for Vxc is presented which is good to within 2% of the exact values. Various limits and graphs of the polarizability are presented

Osteosarcoma: A rare case report and review of literature

Osteosarcoma of the jaws is a rare, aggressive, malignant mesenchymal tumor with an estimated incidence of 5% in 100,000 of the new cases per year. Osteosarcoma of jaws is a very rare disease and may constitute approximately 1% of all head and neck cancers and only 0.14% of intraoral malignancies. Approximately 7% of all osteosarcomas arise in the jawbones. Diagnosis of the tumor is important, especially in early stages for improving prognosis. Here, we report a rare case of osteosarcoma of chondroblastic variant in a 20-year-old girl, who presented with a bony swelling in the right mandibular posterior region, with a radiographic presentation of sunburst appearance, and the histopathological examination confirmed the diagnosis

Local-density-functional model for atoms in momentum space

A local-density-functional model in momentum space enabling direct calculations of electron momentum densities for atomic systems is presented. This is based on the coordinate-space local-density-functional model of Parr et al. in conjunction with quasiclassical phase-space considerations. Within the model, electron-electron interaction and nuclear-electron attraction energies turn out to be simple local functionals of momentum density while kinetic energy has been treated exactly. The momentum densities obtained through this model have a simple algebraic form. Numerical investigations employing these densities reveal that reasonable estimates of various pn expectation values as compared to their Hartree-Fock counterparts can be obtained