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We present an experimental investigation on third-order nonlinear optical properties of RF-sputtered WSe[Formula: see text] thin films using a single-beam [Formula: see text]-scan technique around the optical communication window in a near-infrared spectral band. The nonlinear absorption coefficient was obtained from the open-aperture [Formula: see text]-scan transmission using ultrashort pulses centered at [Formula: see text] excitation wavelength. The results show a reverse saturable absorption signature for all the WSe[Formula: see text] films due to two-photon absorption (TPA) mediated electronic transitions. The dependency of the TPA coefficient on film thickness is analyzed through the modification in an electronic band structure essentially caused due to defects induced in the samples. In addition, we also explored the impact of high laser intensity on the TPA process, which essentially pointed toward a significant contribution of free-carrier absorption at small laser intensities in WSe[Formula: see text] thin films. This investigation provides a basis for optimally tailoring the nonlinear optical properties of transition-metal-dichalcogenides via bandgap engineering for improving photonic device functionality.

Background: Acute febrile encephalopathy is a common clinical syndrome across the globe with the principal cause and manifestations differing according to the demographics. In developing nations like India primary central nervous system infections is the chief culprit. Aim: To identify the etiology of acute febrile encephalopathy and to document the clinical manifestations on presentation. The patients were followed up till discharge and outcome was analyzed in relation with etiology. Materials & Methods: This observational prospective study was done among 50 patients presenting with fever and altered mental status. History, clinical examination, biochemical investigations including cerebrospinal fluid analysis and neuroimaging was done to diagnose the cases individually. The statistical software SPSS version 2.0 was used for the analysis Categorical variables were expressed as number of patients or  percentage of patients and compared across the groups using Pearson’s Chi Square test for independence of attributes. Continuous variables was expressed as mean and standard deviation and compared across the groups using Kruskal Wallis Test. An alpha level of 5% was taken, i.e. if any p value is less than 0.05 it was considered as significant. Results: Out of these 50 patients 70% were due to CNS infections among which viral meningoencephalitis were the commonest cause. The other causes were leptospirosis, brain abscess, cerebral malaria, sepsis associated encephalopathy, acute disseminated encephalomyelitis, neuroleptic malignant syndrome. 14% of patients had sepsis associated encephalopathy and these patients had the highest mortality Conclusion: Acute febrile encephalopathy is a clinically heterogeneous syndrome with a number of causes. It is an important public health issue due to its steep mortality rate. Keywords: acute febrile encephalopathy, meningoencephalitis, mortality, sepsis associated encephalopathy