Dextran mediated MnFe2O4/ZnS magnetic fluorescence nanocomposites for controlled self-heating properties.

Dextran mediated MnFe2O4/ZnS opto-magnetic nanocomposites with different concentrations of ZnS were competently synthesized adopting the co-precipitation method. The structural, morphological, magnetic, and optical properties of the nanocomposites were exhaustively characterized by XRD, HRTEM, FTIR, VSM techniques, and PL spectroscopy. XRD spectra demonstrate the existence of the cubic spinel phase of MnFe2O4 and the cubic zinc blend phase of ZnS in the nanocomposites. HRTEM images show the average crystallite size ranges of 15-21 nm for MnFe2O4 and 14-45 nm for ZnS. Investigation of the FTIR spectra reveals the incorporation of ZnS nanoparticles on the surface of MnFe2O4 nanoparticles by dint of biocompatible surfactant dextran. The nanocomposites exhibit both magnetic and photoluminescence properties. Photoluminescence analysis confirmed the redshift of the emission peaks owing to the trap states in the ZnS nanocrystals. The room temperature VSM analysis shows that the saturation magnetization and coercivity of MnFe2O4 nanoparticles initially increase then decrease with the increasing concentration of ZnS in the nanocomposite. The induction heating analysis shows that the presence of dextran enhances the self heating properties of the MnFe2O4/ZnS nanocomposites which can also be controlled by tailoring the concentration of the ZnS nanoparticles. These suggest that MnFe2O4/Dex/ZnS is a decent candidate for hyperthermia applications.

Molecular characterization of extended spectrum ßlactamase producing bacteria isolated from urinary tract infected patients, Bangladesh.

The aims of the study were to examine the presence of extended spectrum ßlactamase (ESBL) producing pathogen in urinary tract infected (UTI) patients and their respected molecular characterization and classification. The isolates collected from UTI patients attending a private hospital during the period between January and June, 2012, were biochemically identified and subjected to double disc synergy method for the detection of ESBL. ESBL genes were detected by multiplex PCR and antibiotic sensitivity test was performed. Thirty two percent of all Gram negative isolates were found as ESBL producer. Among 65 ESBL positive isolates, 77% were Escherichia coli, 20% Klebsiella pneumoniae and 3% were Pseudomonas spp. Around 48% isolates were found carrying at least one of the four ESBL genes, blaCTX-M, blaTEM, blaSHV and blaOXA, and were found in 32%, 23%, 18.5% and 3% of the isolates respectively. In antibiotic sensitivity assay, higher resistance was found in E. coli than K. pneumonia against ciprofloxacin and nalidixic acid. Interestingly, two E. coli and three K. pneumonia strains were found resistant to only 3rd generation cephalosporines, but susceptible to all other antibiotics assessed. One E. coli strain was found resistant to ciprofloxacin but sensitive to nalidixic acid. Pseudomonas spp. was found resistant to most of the antibiotics. The susceptible rate to nitrofurantoin, amikacin, and gentamicin was also not satisfactory. Susceptibility (100%) to meropenem and imipenem render these as good alternatives to treat UTI. The majority of the isolates were positive for blaCTX-M and adverted to molecular class A. Two strains carrying blaOXA gene along with blaSHV/blaTEM/blaCTX-M, could not be included in any of the established ESBL classification.

Characterization of shiga toxin producing (STEC) and enteropathogenic Escherichia coli (EPEC) in raw yak (Poephagus grunniens) milk and milk products.

Thirty-one shiga toxin-producing (STEC) and 6 enteropathogenic Escherichia coli (EPEC) were isolated from 87 raw yak milk and 63 'churpi' samples. Of 18 stx(1) positive isolates (48.6%), 14 carried stx(1c) (77.7%). Subtyping of 28 stx(2) positive isolates (75.7%) revealed the presence of stx(2c) (9, 32.1%), stx(2d) (3, 10.7%), stx(2e) (1, 3.57%) and stx(2f) (3, 10.7%) variants. Furthermore, intimin (eaeA), enterohaemolysin (ehxA), autoagglutinating adhesin (saa), iha (adherence conferring protein), efa1 (EHEC factor for adherence), bundle forming pilli (bfpA) and toxB (type III secreted protein encoded on LEE Island, similar to toxin B of Clostridium difficile) genes were detected in 14, 16, 12, 4, 3, 2 and 2 isolates, respectively. Univariate and multivariate analysis depicted that both stx(1) and stx(2) or their variants were more likely to occur in isolates from Arunachal Pradesh (p<0.04) rather than Sikkim. Dendogram constructed on the basis of RAPD and ERIC PCR profile distributed the STEC and EPEC isolates in separate clusters irrespective of their sources and serotypes. The STEC and EPEC isolates exhibited resistance against erythromycin, amikacin, azithromycin, amoxicillin, ampicillin+cloxacillin, cephalothin, furazolidone, gentamicin, kanamycin, streptomycin and tetracycline. This is the first ever report on occurrence and characterization of STEC and EPEC isolated from yak milk and milk products.

Effect of fenugreek seeds on the fasting blood glucose level in the streptozotocin induced diabetic rats.

In this experiment defatted Trigonella foenumgraecum (fenugreek seeds/methi seeds) has used as the antidiabetogenic herbal medicine. The experiment was carried out in Bangabandhu Sheikh Mujib Medical University and BIRDEM from 1996 to 1998 on a total of 58 Long Evans rats of either sex. They were 50-60 days young rats with average body weight 72-174 gm. Among the total, 10 rats were treated with only vehicle called as non-diabetic control rats, 48 rats were treated with Streptozotocin (STZ) at a dose of 90 mg in 1 ml of citrate buffer solution per kg body weight, among which 20 were diabetics. Ten (1 died, 1 escaped) diabetic rats were again treated with fenugreek called as Fenugreek-treated diabetic rats and the rest 10 diabetic rats were called as diabetic control rats. The change in the mean fasting blood glucose (FBG) level in different groups of rat from day 5 from streptozotocin injection were higher in diabetic control group and in fenugreek-treated diabetic group than in non diabetic control group. The FBG level on day 13 the mean in non-diabetic control group was 5.21 mmol/L. In diabetic control group and in fenugreek-treated diabetic group the mean FBG level were 24.33 mmol/L and 9.89 mmol/L respectively. So, from this experiment it may be concluded that fenugreek decreases the FBG level considerably by improving diabetes mellitus.