Magnetic Properties of Pure and Doped Gallium Nitride Nanocrystals.

In the present paper, Ga(1− x) Co(x) N, Ga(1− x) Ni(x) N and Ga(1− x) Tb(x) N (0 ≤ x ≤ 0.1) nanocrystals have been synthesized by a facile solvothermal method. Crystallographic characterization of synthesized materials has been done using powder X-ray diffraction technique. Recorded diffraction patterns reveal the formation of wurtzite (hexagonal) structured GaN nanocrystals. Electron microscopic studies have been carried for the detailed topographical and morphological analyses of synthesized nanomaterials. Recorded electron micrographs indicate the formation of nearly mono-disperse nanoparticles, having average size ˜4 nm. Magnetic measurements of doped nanocrystals revealed ferromagnetic behavior at room temperature however pure GaN is diamagnetic at room temperature.

Nanoindentation of Carbon Nanostructures.

In the present research paper carbon nanostructures viz. single walled carbon nanotubes, multi-walled carbon nanotubes, single walled carbon nanohorns and graphene nanoplatelets have been synthesized by CVD technique, hydrothermal method, DC arc discharge method in liquid nitrogen and microwave technique respectively. After synthesis 5 mm thick pallets of given nanomaterial are prepared by making a paste in isopropyl alcohol and using polyvinylidene difluoride as a binder and then these pallets were used for nanoindentation measurements. Hardness, reduced modulus, stiffness, contact height and contact area have been measured using nanoindenter.

An ocular cysticercosis case: Caused by Asian genotype of Taenia solium.

An ocular cysticercosis case of a 42-year-old male, who presented with anterior uveitis is being reported. Microscopical examination of the cyst revealed presence of only one hooklet suggestive of T. solium cysticercus. Mitochondrial DNA analysis confirmed it to be T. solium cysticercus of Asian genotype. This is the first report on molecular typing of cysticercus isolate from ocular cysticercosis patient in India. The study suggests that the molecular analysis of cox1 gene may be a useful diagnostic tool in cases where microscopic examination is not confirmatory.

Human subcutaneous dirofilariasis in India: a report of three cases with brief review of literature.

Human subcutaneous dirofilariasis is a rare infection caused by filarial worms of the genus Dirofilaria. The parasites are transmitted to man by mosquitoes and the infection is manifested as subcutaneous nodules. Excision of the lesion is both diagnostic and therapeutic. Hereby we report three cases of human subcutaneous dirofilariasis. The worms were sent to our department for identification over a period of four years (2006-2009). Of these three patients, two men and one woman were between 15 and 45 years of age. In two cases, the infection manifested as a nodule on face, in one case near lower eyelid and in the other on the cheek, while in the third case as an itchy nodule on the abdomen. It is emphasized that both clinicians and microbiologists should have an increased awareness of this entity and include dirofilariasis in the differential diagnosis of patients presenting with subcutaneous nodules.

Ophthalmomyiasis: three cases from North India.

Three cases of external ophthalmomyiasis are reported here. The larvae were identified to be Oestrus ovis in two cases and Cochliomyia hominivorax in one. Two of the patients were immunocompetent while one was undergoing treatment for squamous cell carcinoma of eyelid. In the latter myiasis led to complete destruction of the eye.

Photoluminescence decay kinetics of doped ZnS nanophosphors.

Doped nanophosphor samples of ZnS:Mn, ZnS:Mn, Co and ZnS:Mn, Fe were prepared using a chemical precipitation method. Photoluminescence (PL) spectra were obtained and lifetime studies of the nanophosphors were carried out at room temperature. To the best of our knowledge, there are very few reports on the photoluminescence investigations of Co-doped or Fe-doped ZnS:Mn nanoparticles in the literature. Furthermore, there is no report on luminescence lifetime shortening of ZnS:Mn nanoparticles doped with Co or Fe impurity. Experimental results showed that there is considerable change in the photoluminescence spectra of ZnS:Mn nanoparticles doped with X (X = Co, Fe). The PL spectra of the ZnS:Mn, Co nanoparticle sample show three peaks at 410, 432 and 594 nm, while in the case of the ZnS:Mn, Fe nanoparticle sample the peaks are considerably different. The lifetimes are found to be in microsecond time domain for 594 nm emission, while nanosecond order lifetimes are obtained for 432 and 411 nm emission in ZnS:Mn, X nanophosphor samples. These lifetimes suggest a new additional decay channel of the carrier in the host material.

Altered lipid parameters in patients infected with Entamoeba histolytica, Entamoeba dispar and Giardia lamblia.

Information on the effect of parasitic infections on lipid parameters is scarce. Certain parasites induce significant changes in lipid parameters, as demonstrated by the fact that substitution of lipid/cholesterol for serum in axenic culture medium (in vitro) and in experimental models (in vivo) supports vigorous growth of Entamoeba histolytica. Thus, significant changes in lipid parameters may be induced in an infected host. Blood samples are obtained from intestinal amoebiasis patients passing E. histolytica (n=8), E. dispar (n=15) or Giardia lamblia (n=9) cysts, or diagnosed with amoebic liver abscess (ALA; n=50) and from apparently normal healthy individuals (control group; n=30). Levels of total serum cholesterol, high-density lipoprotein and low-density lipoprotein are assessed using commercial kits. E. histolytica and E. dispar isolates are differentiated by hexokinase isoenzyme electrophoresis and by enzyme-linked immunosorbent assay (ELISA; Techlab) tests. Results show that E. histolytica, E. dispar and G. lamblia cyst passers had significantly lower levels of total serum cholesterol (73.42 +/- 2.24 mg/dL), compared to levels in ALA cases (101 +/- 2.85 mg/dL) and in controls (166.26 +/- 2.02 mg/dL). Further study of a greater number of cases is needed to explore the relevance of this finding.

Acanthamoeba adherence to soft contact lens and human corneal stroma.

In the present study, the adhesibility of Acanthamoeba castellani trophozoites and cysts to hydrogel contact lenses and to human cornea was investigated. Segments of unworn contact lenses were prepared (120 segments in total). In addition, 8 corneal buttons were obtained from 8 enucleated eyes. And each cornea cut into 8 radial segments. To these lens and corneal segments, 1.2 x 106/ml and 1.3 x 106/ml of cysts and trophozoites respectively were added under varying conditions. The adhesion was checked at 0, 3 and 24 hours after the exposure. Adhesion analysis showed that the trophozoites adhered equally well to lens or cornea. There is an increase in the number of trophozoites adhering to contact lenses as well as cornea. This difference is more significant for contact lenses. Washing of contact lenses significantly decreased the adherence of the trophozoites after 3 hours of incubation. When the comparison of adhesion was done between the unwashed worn and unwashed unworn contact lenses, it was observed that there was a significant difference in adherence to new lenses where the adherence was much lower. The study shows that washing of contact lenses does decrease the chances of colonization by Acantamoeba catellani and also that older lenses have higher chances of getting colonized probably due to the occurrence of scratches et. on the surface which may help in colonization.

Gastrointestinal bleeding due to worm infestation, with negative upper gastrointestinal endoscopy findings: impact of enteroscopy.

BACKGROUND AND STUDY AIMS: In cases of hookworm and roundworm infestation, chronic occult bleeding is well known, but acute gastrointestinal bleeding is rarely described. We report five patients with worm infestation who presented with acute massive gastrointestinal bleeding. PATIENTS AND METHODS: Over 1 year, we have encountered 15 patients with obscure gastrointestinal bleeding. All the patients had normal findings on upper gastrointestinal endoscopy. Push enteroscopy was performed in each patient and evaluation of the proximal 40-50 cm of the jejunum was done. RESULTS: Five patients (four men, one woman; average age 50 yr, range 40-60) had worm infestation (two hookworm, three roundworm). All the patients had gastrointestinal bleeding (five had melena, one hematemesis, and two hematochezia) for a duration of 7-14 days. Hemoglobin ranged from 2.8 to 9 g/dl. Push enteroscopy revealed fresh blood in the jejunum, multiple erosions, and hookworms in two patients and roundworms in three patients. Hookworms were retrieved endoscopically in two patients whereas roundworms could be retrieved in only one patient. All the patients were treated with mebendazole (100 mg twice a day for 3 days), iron, and folic acid. Gastrointestinal bleeding subsided in all the patients. CONCLUSIONS: In developing countries, worm infestation should be considered an important cause of obscure acute gastrointestinal bleeding. Evaluation of the jejunum using an enteroscope will result in more frequent diagnosis of worms as a cause of acute gastrointestinal bleeding which might have been classified as obscure gastrointestinal bleeding.

Diagnostic value of push-type enteroscopy: a report from India.

OBJECTIVE: We sought to assess the diagnostic value of push-type enteroscopy in relation to indications. METHODS: Ninety-nine consecutive patients (mean age, 42+/-15 yr; 65 men) with suspected small bowel disorders underwent push enteroscopy. The indications were chronic diarrhea (n = 54), obscure gastrointestinal (GI) bleeding (n = 21), abdominal pain (n = 10), abnormal radiological studies of small bowel (n = 5), iron deficiency anemia (n = 5), and others (n = 4). Push enteroscopy was performed using the Olympus SIF-10 (160-cm) enteroscope. RESULTS: Endoscopic examination of the jejunum was successful in all the patients, except one with a distal duodenal stricture. The length of the jejunum examined ranged from 10 to 70 cm. The time taken to complete the procedure varied from 2 to 30 min. Lesions were found in nine (42.8%) patients with obscure GI bleeding; six (28.5%) had worms (Ascaris lumbricoides [n = 3], Ankylostoma duodenale [n = 3]) in the jejunum, producing multiple erosions and bleeding points. In the chronic diarrhea group, a diagnosis was made in 13 (24%) patients on enteroscopic visualization and jejunal histology: celiac disease (n = 6), tropical sprue (n = 3), Crohn's disease (n = 1), secondary lymphangiectasia (n = 1), strongyloidiasis (n = 1), and nodular lymphoid hyperplasia with giardiasis (n = 1). In patients with abdominal pain, enteroscopy provided a diagnosis in one (10%) patient. No positive diagnosis could be made on enteroscopy in patients with iron deficiency anemia and abnormal radiological studies of small bowel. CONCLUSION: Push-type enteroscopy is a useful test in the evaluation of patients with obscure GI bleeding and chronic diarrhea. In developing countries, in patients with obscure GI bleeding, the presence of worms in the jejunum is an important finding on enteroscopy. Tropical sprue, giardiasis, and strongyloidiasis are distinct findings in patients with chronic diarrhea in the present series.

Fasciolopslasis--a re-emerging infection in Azamgarh (Uttar Pradesh).

Fasciolopsiasis is endemic in the far east. In India, there have been a few reports of the infection, prior to the 1990's. We report two cases from Azamgarh district of Uttar Pradesh. Both the cases were from nearby villages where water chestnuts are cultivated. These may be a source of infection. Pigs are commonly observed in these areas and and may be the source of ova. The only missing link is the finding of infected snails. Presence of at least three cases (one reported earlier) in the area indicates the potential for the infection to re-emerge. Further epidemiological studies are needed to analyse the various ecological factors of transmission. Fasciolopsiasis is endemic in China, Taiwan, Vietnam and Thailand. In India, (Fascilopsis buski) infections in man have been reported earlier from Assam, Maharashtra, Tamil Nadu and parts of Uttar Pradesh. However, to the best of our knowledge, no such reports have been made since 1990's. We herewith report two recent cases from district Azamgarh, Uttar Pradesh (U.P.), India. Factors, such as cultivation of water chestnuts, presence of snails as intermediate hosts and pigs as definitive host in this geographical area seem to be suggestive of an endemic focus and thus needs further epidemiological survey for preventive and control measures, at the earliest.

An experimental model of ameboma in guinea pig.

Among the wide variety of clinicopathological manifestations of intestinal amebiasis, amebomas occur rarely and their pathogenesis is not well understood. When cholesterol-fed, 2- to 4-week-old guinea pigs were infected intracecally with a virulent, monoaxenic strain of Entamoeba histolytica, gross and histologically characteristic amebomas developed in 85% of the animals by the 3rd day, in 94% by the 9th day, and in 96% by the 12th day postinfection, by which time most of them had died. Amebomas were confirmed by histopathology. Thus, a model of consistent production of amebomas was documented.

Virulence of pathogenic and non-pathogenic zymodemes of Entamoeba histolytica (Indian strains) in guinea-pigs.

Guinea-pigs were inoculated with Entamoeba histolytica strains isolated from cases of amoebic liver abscess, amoebic dysentery and asymptomatic cyst passers and the strains were classified in zymodemes by isoenzyme electrophoresis. It was observed that certain non-pathogenic zymodemes were potentially pathogenic for the guinea-pigs. The relationship of zymodemes and virulence in laboratory animals is discussed.

Mechanism of innate immunity to amoebic infection in guineapigs.

The direct lymphocyte cytotoxicity and antibody dependent cell mediated cytotoxicity against Entamoeba histolytica was studied in 3-4 wk old and 8-10 wk old guineapigs. Both these parameters were significantly increased in splenic cells in the older animals. This might be due to maturation of the immune system or to natural infection by related parasite, leading to immunity.