Identification and evaluation of defect levels in low-dimensional materials is an important aspect in quantum science. In this article, we report a facile synthesis method of low-dimensional hexagonal boron nitride (h-BN) and study light emission characteristics due to the defects. The thermal annealing procedure is optimized to obtain clean multilayered h-BN as revealed by transmission electron microscopy. UV–vis spectroscopy shows the optical energy gap of 5.28 eV, which is comparable to the reported energy gap for exfoliated, clean h-BN samples. X-ray photoelectron spectroscopy reveals the location of the valence band edge at 2 eV. The optimized synthesis route of h-BN generates two kinds of defects, which are characterized using room-temperature photoluminescence (PL) measurements. The defects emit light at 4.18 eV [deep-UV (DUV)] and 3.44 eV (UV) photons. The intensity of PL has an oscillatory dependence on the excitation energy for the defect emitting DUV light. A series of spectral lines are observed with the energy ranging between 2.56 and 3.44 eV. The average peak-to-peak energy separation is about 125 meV. The locations of the spectral lines can be modeled using Franck–Condon-type transition and associated with displaced harmonic oscillator approximation. Our facile route gives an easier approach to prepare clean h-BN, which is essential for classical two-dimensional material-based electronics and single-photon-based quantum devices.

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Evaluation of the defect levels in low-dimensional materials is an important aspect of quantum science. In this article, we report a facile synthesis method of hexagonal boron nitride (h-BN) and evaluate the defects and their light emission characteristics.The thermal annealing procedure is optimized to obtain clean h-BN. The UV-Vis spectroscopy shows the optical energy gap of 5.28 eV which is comparable to the reported energy gap for exfoliated, clean h-BN samples. The optimized synthesis route of h-BN 1 has generated two kinds of defects which are characterised using room temperature photoluminescence measurements. The defects emit light at 4.18 eV (in deep ultraviolet region) and 3.44 eV (ultraviolet), respectively. The defect emitting deep ultraviolet (DUV) has oscillatory dependency on the excitation energy, while that emitting 3.44 eV light (ZPL3.44 eV) has a phonon bands with mean energy level separation of 125 meV measured at room temperature. This agrees very well with the Franck-Condon-like structure having regularly spaced energy levels, which are typical indications of single defect levels in the low dimensional h-BN.

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Background: Antibiotic stewardship aims to optimise restricted antibiotic use and thereby prevent the emergence of antibiotic resistance and improve treatment outcome. Resistance to conventional antimicrobial’s is a major reason why restricted antibiotics are prescribed. Aim: To assess the prescribing pattern of restricted antibiotics, the indications for which restricted antibiotics were prescribed, the drug related problems associated and the sensitivity pattern of the isolated organisms. Results: Out of 340 patients included in the study, majority of patients was in the age group of 58-67(60.06 ±14.90) in both genders. There was a male (64.12%) dominance observed in the study populace and the minimum and maximum age observed was 18 and 93 years respectively. Most commonly prescribed antibiotic was Piperacillin tazobactum (31%) followed by Linezolid (16.06%). Empirically the most prescribed antibiotic was Piperacillin tazobactum (27.37%) while in definitive therapy it was Cefepime tazobactum (10.63%). The most common indication for which restricted antibiotics prescribed were for respiratory tract infection (n=116), followed by infection prophylaxis (n=114). Mean days of restricted antibiotic therapy was found to be 8.85 days ± 8.11. The maximum duration of antibiotic treatment was 62 days and minimum was 1 day. In 47% of cases IV to oral conversion was possible. When analysed retrospectively, in majority of the patients the duration of restricted antibiotic treatment was inappropriate (69.71%) while the inappropriateness in frequency and dose were 7.05% and 3.23% respectively. The total number of cultures collected were 292 in that 120 cultures were urine and found growth in 50.83%, followed by 84 cultures in sputum which accounted for 67.85% growth. The most common organism isolated was Klebsiella pneumoniae 39.73% cases followed by Pseudomonas aeruginosa 17.46% and Acinetobacter baumannii15.41. There was clinical cure in 91.47% of cases. Conclusion: When analysed retrospectively majority of the restricted antibiotics showed inappropriateness. This higher amount of inappropriateness could have been avoided to a certain extent, by the timely interventions of a clinical pharmacist. By implementing an effective antimicrobial stewardship program we could improve the rational use of restricted antibiotics and thereby prevent the future resistance and improve clinical outcome.