Burkholderia vietnamiensis causing a non-lactational breast abscess in a non-cystic fibrosis patient in Tamil Nadu, India.

Burkholderia cepacia complex is a Gram-negative opportunistic pathogen usually found in people with an immunocompromised condition such as cystic fibrosis (CF). In a tropical country like India, this organism has been associated with a number of hospital-acquired infections including sepsis. We present here a report of a case of Burkholderia vietnamiensis causing a non-lactational breast abscess in a non-CF patient. The pathogen was identified as B. cepacia using Vitek system and matrix-assisted laser desorption ionisation-time of flight. This was confirmed by polymerase chain reaction (PCR) using recA genus-specific gene and sequencing of the PCR amplicons. recA-restriction fragment length polymorphism and recA gene sequencing revealed that the isolate is B. vietnamiensis. This is the first description of B. vietnamiensis isolated from a clinical case from India.

Near Band Edge Emission by Free Exciton Decay and Intrinsic Ferromagnetic Ordering of Cu-Doped SnO2 Hollow Nanofibers.

High quality nanocrystalline pristine and Cu-doped SnO2 hollow nanofibers were successfully prepared through simple and effective electrospinning technique. Nanofibers calcined at 600 °C for 3 h were characterized with different analytical techniques such as X-ray diffraction (XRD), Transmission electron Microscope (TEM) and Vibrating sample magnetometer (VSM). Observed TEM images and XRD patterns were corroborate to the formation of tetragonal crystalline SnO2 hollow nanofibers with rutile phase. Excellent optical behaviour was observed for Cu-doped SnO2. Highly intense near band edge emission at 3.58 eV for Cu-doped SnO2 evidences the free exciton decay process in the hollow nanofibers. For the first time we have reported here the near band edge PL emission in Cu-doped SnO2 tubular hollow nanostructure. This study substantiates that material potential for UV-lasing application. In addition to the above, magnetic measurement ascribes that Cu-doped SnO2 exhibit the intrinsic room temperature ferromagnetism within the low field strength. The occurrence of ferromagnetism in Cu-doped SnO2 is directly related to the p-d ferromagnetic exchange coupling between the local magnetic moment of Cu2+ and the polarized valence electrons of surrounding oxygen. Over all this study provides the primary information about tunable multifunctionality of SnO2 hollow nanostructures by adding the non-magnetic Cu ions.

Optical and magnetic studies of electrospun Mn-doped SnO2 hollow nanofiber dilute magnetic semiconductor.

The hollow nanofibers of Mn-doped SnO2 were fabricated by electrospinning method. The structural and magnetic properties of the electrospun fibers calcined at 600 degrees C were studied. X-ray diffraction patterns of the nanofibers showed broad diffraction peaks and were indexed to the characteristic diffraction pattern of tetragonal SnO2. The hollow fiber micro-structure of Mn-doped and pure SnO2 were confirmed from the observed HRSEM and TEM analysis. Typical diameter of the hollow nanofibers was found to be around 150 nm. Strong emission peak in the visible region of the PL spectra characteristic of the optical activity of the SnO2 is obtained. Surface composition of the nanofiber and successful incorporation of Mn into SnO2 were confirmed from intense peaks recorded in the XPS spectra. Finally, a reasonable ferromagnetic transition observed at 10 K in the Mn-doped SnO2, substantiates that the presence of undetectable Sn-Mn solid solution or the formation of Mn based oxide secondary phases. It concludes that the induced ferromagnetism is only due to the precipitated impurity phases and does not arise from any intrinsic pure SnO2 or the dopant.