Impedimetric Chemosensing of Volatile Organic Compounds Released from Li-Ion Batteries.

Detection of toxic and flammable gases and volatile organic compounds (VOCs) released from Li-ion batteries during thermal runaway can generate an early warning. A submicron (∼0.15 µm)-thick poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) sensor film is coated on a platinum electrode through a facile aqueous dispersion. The resulting sensor reliably detected different volatile organic compounds (VOCs) released during the early stages of thermal runaway of lithium-ion batteries (LIBs) even at low concentrations. The single-electrode sensor utilizes impedance spectroscopy to measure ethyl methyl carbonate and methyl formate concentrations at 5, 15, and 30 ppm independently and in various combinations using ethanol as a reference. In contrast to DC resistance measurement, which provides a single parameter, impedance spectroscopy provides a wealth of information, including impedance and phase angle at multiple frequencies as well as fitted charge transfer resistance and constant-phase elements. Different analytes influence the measurement of different parameters to varying degrees, enabling distinction using a single sensing material. The response time for ethyl methyl carbonate was measured to be 6 s. Three principal components (PCs) preserve more than 95% of information and efficiently enable discrimination of different classes of analytes. Application of low-power PEDOT:PSS-based gas sensors will facilitate cost-effective early detection of VOCs and provide early warning to battery management systems (BMS), potentially mitigating catastrophic thermal runaway events.

Atypical Presentation of Granular Cell Tumor Involving Tongue: A Rare Case Report.

Granular cell tumor (GCT) is a rare benign tumor chiefly affecting the orofacial region, especially tongue. The origin of this neoplasia, after remaining a controversy for years, was finally identified to be from Schwann cell or neuroendocrine cell. They usually present as asymptomatic, firm, sessile, submucosal, solitary, or multiple nodule/papule like lesions. Histopathologically, the presence of sheets, cords or nests of large cells having abundant, eosinophilic granular cytoplasm, and pseudoepitheliomatous hyperplasia are the characteristic features of this neoplasm. Immunohistochemical stains such as S100, Cluster of differentiation 68, neuron-specific enolase, and laminin also aid in the proper diagnosis of granular cells. We hereby present a case of GCT in a 50-year-old male, which had a unique exophytic appearance, probably being only the second to be reported till date.

Oral sarcoidosis aiding in diagnosis of underlying systemic disease.

Sarcoidosis is a chronic, multisystemic, granulomatous disease of unknown aetiology characterised by the formation of non-caseating granuloma. It shows slight female predominance and has a bimodal age distribution. Lungs, skin, eye and liver are commonly affected. The oral lesion, though uncommon, may present as submucosal nodule, papule or superficial ulceration. Occasionally, oral lesion may be the first manifestation of underlying systemic disease. This case is interesting because it emphasises that dental practitioners may play a key role in early recognition of the clinical presentation of this multifaceted disease, and thereby aid in the diagnosis of the systemic condition. The present report deals with a case of sarcoidosis affecting the buccal mucosa in a 48-year-old woman. The patient was treated with oral prednisolone and within 4 months of corticosteroid therapy, the oral lesion regressed with no recurrence or new lesion noted over a period of 1 year.

Bacteriorhodopsin-ZnO hybrid as a potential sensing element for low-temperature detection of ethanol vapour.

Zinc oxide (ZnO) and bacteriorhodopsin (bR) hybrid nanostructures were fabricated by immobilizing bR on ZnO thin films and ZnO nanorods. The morphological and spectroscopic analysis of the hybrid structures confirmed the ZnO thin film/nanorod growth and functional properties of bR. The photoactivity results of the bR protein further corroborated the sustainability of its charge transport property and biological activity. When exposed to ethanol vapour (reducing gas) at low temperature (70 °C), the fabricated sensing elements showed a significant increase in resistivity, as opposed to the conventional n-type behaviour of bare ZnO nanostructures. This work opens up avenues towards the fabrication of low temperature, photoactivated, nanomaterial-biomolecule hybrid gas sensors.