Malignant peripheral nerve sheath tumor of the cervical vagus nerve in a neurofibromatosis type 1 patient - An unusual presentation

Malignant peripheral nerve sheath tumors (MPNST’S) of the head and neck comprise 2% to 6% of head and neck sarcomas. These tumors may arise as sporadic variants or in patients with neurofibromatosis (NF). Development of these MPNST’s is one of the serious complications of neurofibromatosis type 1(NF1). To our knowledge there are only two reported cases of MPNST’s arising in the cervical vagal nerve, occurring in NF1 patients. We present here an NF1 patient who developed an MPNST of the cervical vagus nerve and presented only with a cervical swelling and hoarseness

Heavy Quarkonium Potential Model and the 1P1{}^1P_1 State of Charmonium

A theoretical explanation of the observed splittings among the P~states of charmonium is given with the use of a nonsingular potential model for heavy quarkonia. We also show that the recently observed mass difference between the center of gravity of the ${}^3P_J$ states and the ${}^1P_1$ state of $c\bar{c}$ does not provide a direct test of the color hyperfine interaction in heavy quarkonia. Our theoretical value for the mass of the ${}^1P_1$ state is in agreement with the experimental result, and its E1 transition width is 341.8~keV. The mass of the $\eta_c'$ state is predicted to be 3622.3~MeV.Comment: 15 page REVTEX documen

Undifferentiated Carcinoma of Larynx of Nasopharyngeal Type

Undifferentiated carcinoma of nasopharyngeal type arising in the larynx is unusual. This type of carcinoma-which occurs almost exclusively in nasopharynx-is very infrequent in the larynx (0.2%). Till date only 17 cases are reported in the medical literature. We present the clinical and histopathological findings along with the management of one additional case of undifferentiated carcinoma of nasopharyngeal type in the larynx which was managed successfully with radiotherapy

Origin of the unusual dependence of Raman D band on excitation wavelength in graphite-like materials

We have revisited the still unresolved puzzle of the dispersion of the Raman disordered-induced D band as a function of laser excitation photon energy E$_L$ in graphite-like materials. We propose that the D-mode is a combination of an optic phonon at the K-point in the Brillioun zone and an acoustic phonon whose momentum is determined uniquely by the double resonance condition. The fit of the experimental data with the double-resonance model yields the reduced effective mass of 0.025m$_{e}$ for the electron-hole pairs corresponding to the A$_{2}$ transition, in agreement with other experiments. The model can also explain the difference between $\omega_S$ and $\omega_{AS}$ for D and D$^{\star}$ modes, and predicts its dependence on the Raman excitation frequency.Comment: 4 figures in eps forma

Specific heat at constant volume in the thermodynamic model

A thermodynamic model for multifragmentation which is frequently used appears to give very different values for specific heat at constant volume depending upon whether canonical or grand canonical ensemble is used. The cause for this discrepancy is analysed.Comment: Revtex, 7 pages including 4 figure

Chi_1 and Polarisation Asymmetries for Quarkonia at High Orders in Non-relativistic QCD

We study doubly polarised asymmetries of c-cbar and b-bbar mesons in hadro- and photo-production at low transverse momentum in non-relativistic QCD to high orders in the relative velocity of the pair, v. We give the complete set of expressions required for the asymmetries up to order v^9. The asymmetries in the production of eta_{c,b} states are a stable measure of the polarised gluon densities. The asymmetries for chi_{c,b}, J/psi, psi', and the various Upsilon states are stringent tests of the NRQCD scaling relations.Comment: 21 pages LaTeX including 2 figure

Broadband optical radiation detector

A method and apparatus for detecting optical radiation by optically monitoring temperature changes in a microvolume caused by absorption of the optical radiation to be detected is described. More specifically, a thermal lens forming material is provided which has first and second opposite, substantially parallel surfaces. A reflective coating is formed on the first surface, and a radiation absorbing coating is formed on the reflective coating. Chopped, incoming optical radiation to be detected is directed to irradiate a small portion of the radiation absorbing coating. Heat generated in this small area is conducted to the lens forming material through the reflective coating, thereby raising the temperature of a small portion of the lens forming material and causing a thermal lens to be formed therein

Double-beam optical method and apparatus for measuring thermal diffusivity and other molecular dynamic processes in utilizing the transient thermal lens effect

A sample material was irradiated by relatively high power, short pulses from a dye laser. Energy from the pulses was absorbed by the sample material, thereby forming a thermal lens in the area of absorption. The pulse repetition rate was chosen so that the thermal lens is substantially dissipated by the time the next pulse reaches the sample material. A probe light beam, which in a specific embodiment is a relatively low power, continuous wave (cw) laser beam, irradiated the thermal lens formed in the sample material. The intensity characteristics of the probe light beam subsequent to irradiation of the thermal lens is related to changes in the refractive index of the sample material as the thermal lens is formed and dissipated