Indian J Otolaryngol Head Neck Surg
December 2022
Hearing is an important sense organ for human beings essential for speech, language and overall development. Universal neonatal hearing screening programmes are mandatory in many developed countries. In India out of 1000 neonates approximately 5-6 infants are diagnosed with hearing impairment but still universal neonatal hearing screening programme is in its infancy.
View Article and Find Full Text PDFIndian J Otolaryngol Head Neck Surg
December 2022
Tracheobronchial foreign body aspiration amongst paediatric population is one of the commonest challenges faced by the otolaryngologist. Subcutaneous emphysema is an uncommon presentation of this condition and the ENT specialist needs to have a high index of clinical suspicion of a foreign body. We report a case of 2-year old child presented with subcutaneous emphysema later diagnosed with a foreign body in the bronchus.
View Article and Find Full Text PDFIndian J Otolaryngol Head Neck Surg
June 2021
Olfactory dysfunction (OD) and gustatory dysfunction (GD) has been reported as one of the presenting symptoms amongst COVID-19 patients. However the literature available is disjunct on this aspect. This study is conducted to identify the prevalence of olfactory and/or gustatory dysfunction in patients with coronavirus disease in Northern part of India.
View Article and Find Full Text PDFSilicon-based microelectromechanical systems (MEMS) sensors have become ubiquitous in consumer-based products, but realization of an interconnected network of MEMS devices that allows components to be remotely monitored and controlled, a concept often described as the "Internet of Things," will require a suite of MEMS materials and properties that are not currently available. We report on the synthesis of metallic nickel-molybdenum-tungsten films with direct current sputter deposition, which results in fully dense crystallographically textured films that are filled with nanotwins. These films exhibit linear elastic mechanical behavior and tensile strengths exceeding 3 GPa, which is unprecedented for materials that are compatible with wafer-level device fabrication processes.
View Article and Find Full Text PDFElemental boron exhibits many polymorphs in nature based mostly on an icosahedral shell motif, involving stabilization of 13 strong multicenter intraicosahedral bonds. It is commonly accepted that the most thermodynamic stable structure of elemental boron at atmospheric pressure is the β rhombohedral boron (β-B). Surprisingly, using high-resolution transmission electron microscopy, we found that pure boron powder contains grains of two different types, the previously identified β-B containing a number of randomly spaced twins and what appears to be a fully transformed twinlike structure.
View Article and Find Full Text PDFNanotwinned structures in superhard ceramics rhombohedral boron suboxide (R-B6O) have been examined using a combination of transmission electron microscopy (TEM) and quantum mechanics (QM). QM predicts negative relative energies to R-B6O for various twinned R-B6O (denoted as τ-B6O, 2τ-B6O, and 4τ-B6O), consistent with the recently predicted B6O structure with Cmcm space group (τ-B6O) which has an energy 1.1 meV/B6O lower than R-B6O.
View Article and Find Full Text PDFThe roles of grain boundaries and twin boundaries in mechanical properties are well understood for metals and alloys. However, for covalent solids, their roles in deformation response to applied stress are not established. Here we characterize the nanotwins in boron suboxide (B6O) with twin boundaries along the {0111} planes using both scanning transmission electron microscopy and quantum mechanics.
View Article and Find Full Text PDFAmorphous shear bands are the main deformation and failure mode of super-hard boron carbide subjected to shock loading and high pressures at room temperature. Nevertheless, the formation mechanisms of the amorphous shear bands remain a long-standing scientific curiosity mainly because of the lack of experimental structure information of the disordered shear bands, comprising light elements of carbon and boron only. Here we report the atomic structure of the amorphous shear bands in boron carbide characterized by state-of-the-art aberration-corrected transmission electron microscopy.
View Article and Find Full Text PDFCapsaicin is employed as a condiment and colorant in the cosmetic and pharmaceutical industries. Metabolism of capsaicin produces reactive phenoxy radicals, which inflict damage to DNA. Micronutrients such as zinc and selenium facilitate the expression of tissue repair factors, and lycopene has natural antioxidant action.
View Article and Find Full Text PDFCeramics typically have very high hardness, but low toughness and plasticity. Besides intrinsic brittleness associated with rigid covalent or ionic bonds, porosity and interface phases are the foremost characteristics that lead to their failure at low stress levels in a brittle manner. Here we show that, in contrast to the conventional wisdom that these features are adverse factors in mechanical properties of ceramics, the compression strength, plasticity and toughness of nanocrystalline boron carbide can be noticeably improved by introducing nanoporosity and weak amorphous carbon at grain boundaries.
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