Peripheral T Cell Lymphoma of Parotid Gland: A Diagnostic Challenge.

Peripheral T-cell lymphoma of salivary gland is a rare clinical entity most commonly involving the parotid gland and mimics a salivary gland carcinoma. It has an aggressive clinical course with poor prognosis. Majority of the cases are diagnosed after surgical excision whereas the principal treatment is non-surgical (chemotherapy). Core biopsy is an excellent method of identifying these indeterminate lesions pre-operatively which would avoid unnecessary surgical intervention. We present a case report with diagnostic challenge in identifying peripheral T cell lymphoma of salivary gland with the review of literature.

Molecular probe dynamics reveals suppression of ice-like regions in strongly confined supercooled water.

The structure of the hydrogen bond network is a key element for understanding water's thermodynamic and kinetic anomalies. While ambient water is strongly believed to be a uniform, continuous hydrogen-bonded liquid, there is growing consensus that supercooled water is better described in terms of distinct domains with either a low-density ice-like structure or a high-density disordered one. We evidenced two distinct rotational mobilities of probe molecules in interstitial supercooled water of polycrystalline ice [Banerjee D, et al. (2009) ESR evidence for 2 coexisting liquid phases in deeply supercooled bulk water. Proc Natl Acad Sci USA 106: 11448-11453]. Here we show that, by increasing the confinement of interstitial water, the mobility of probe molecules, surprisingly, increases. We argue that loose confinement allows the presence of ice-like regions in supercooled water, whereas a tighter confinement yields the suppression of this ordered fraction and leads to higher fluidity. Compelling evidence of the presence of ice-like regions is provided by the probe orientational entropy barrier which is set, through hydrogen bonding, by the configuration of the surrounding water molecules and yields a direct measure of the configurational entropy of the same. We find that, under loose confinement of supercooled water, the entropy barrier surmounted by the slower probe fraction exceeds that of equilibrium water by the melting entropy of ice, whereas no increase of the barrier is observed under stronger confinement. The lower limit of metastability of supercooled water is discussed.

Vitrification and glass transition of water: insights from spin probe ESR.

Three long-standing problems related to the physics of water, viz., the possibility of vitrifying bulk water by rapid quenching, its glass transition, and the supposed impossibility of obtaining supercooled water between 150 and 233 K, the so-called "no man's land" of its phase diagram, are studied using the highly sensitive technique of spin probe ESR. Our results suggest that water can indeed be vitrified by rapid quenching; it undergoes a glass transition at approximately 135 K, and the relaxation behavior studied using this method between 165 K and 233 K closely follows the predictions of the Adam-Gibbs model.