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  • Author: Shalini Sharma x
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CVD synthesis of graphene nanoplates on MgO support

Abstract

Synthesis of graphene directly on MgO has been carried out and the structural properties of the obtained material have been investigated. Few-layered graphene was produced by simple thermal decomposition of methane over MgO powder at 950 °C in a CVD reactor. The samples were purified by 10 N HNO3 treatment, and studied by TEM, Raman spectroscopy, EDAX and SEM. TEM clearly indicated the formation of graphene. EDAX showed that the purified sample contained only carbon and no traces of MgO. The characteristic Raman features of graphene were also seen as D-band at 1316 cm−1, G-band at 1602 cm−1, and a small 2D-band at 2700 cm−1 in the Raman spectra. The strong D-band suggests that the graphene possess large number of boundary defects. The small 2D-band indicates the formation of few-layered graphene.

Open access
Adrenal Histoplasmosis in Immunocompetent Patients Presenting as Adrenal Insufficiency

Abstract

Objective: Histoplasmosis is an infectious disease caused by the dimorphic fungus Histoplasma capsulatum, endemic in central and eastern states of United States, South America and Africa. India is considered to be non-endemic area for histoplasmosis. Disseminated histoplasmosis may affect almost all systems. Disseminated histoplasmosis with asymptomatic adrenal involvement has been described in immunocompromised patients; whereas isolated adrenal involvement with adrenal insufficiency as the presenting manifestation of the disease is rare.

Material and Method: Twelve patients from a non-endemic area with adrenal histoplasmosis, who were immunocompetent and diagnosed as adrenal histoplasmosis by cytology/histopathology between January 2012 to December 2014 were studied. 18F-FDG PET/CT (fluorodeoxyglucose positron emission tomography/computed tomography) was used to assess the extent of involvement.

Results: There were a total of 12 immunocompetent males (mean age: 56.9 years). Ten patients had bilateral adrenal involvement and two had a unilateral left adrenal mass. All the patients had histopathologically/cytologically proven adrenal histoplasmosis. Two patients had simultaneous histoplasmosis of other sites, one in the epiglottis and the other in the alveolus. 18F-FDG PET/CT was performed in 10 patients showing high FDG uptake in the adrenals. All these patients received Amphotericin B and/or Itraconazole treatment that led to symptomatic improvement.

Conclusion: A diagnosis of invasive fungal infection requires a high index of suspicion, especially in immunocompetent patients who present with nonspecific symptoms, clinical signs, laboratory and radiological features that can resemble adrenal neoplasms. Clinical specimens must be sent for cytopathology/histopathology together with fungal culture for a definite diagnosis and appropriate management.

Open access
A testimony of detachment of an inland lake from marine influence during the mid-Holocene in the Vestfold Hills region, East Antarctica

Abstract

A 47 cm long sediment core collected from an inland lake of the Vestfold Hills, East Antarctica has been examined to reconstruct the palaeolacustrine environmental changes. The core shows dates at two core intervals of 18-19 cm and 28-29 cm as 5050±98 yrs BP and 5560±96 yrs BP, respectively. The core exhibits a good amount of diatom population throughout the length. Prior to 5560±96 yrs BP, the core shows high abundance of diatom population (>10×107 g-1) along with sufficient salt crystal, which indicates the connection of this lake with the marine environment. From 5560±96 yrs BP to 5050±98 yrs BP the total number diatoms decreased substantially along with the decrease in salt crystal, which indicates the withdrawal of the marine influence from the lake during that period. From 5050±98 yrs BP to Recent, the low number of diatoms and the rare occurrence of salt crystal suggest that the lake remained mostly detached from the sea during the last 5000 yrs.

Open access