Syntheses and catalytic oxotransfer activities of oxo molybdenum(vi) complexes of a new aminoalcohol phenolate ligand.

The new aminoalcohol phenol 2,4-di-tert-butyl-6-(((2-hydroxy-2-phenylethyl)amino)methyl)phenol (H2L) was prepared by a facile solvent-free synthesis and used as a tridentate ligand for new cis-dioxomolybdenum(vi)(L) complexes. In the presence of a coordinating solvent (DMSO, MeOH, pyridine), the complexes crystallise as monomeric solvent adducts while in the absence of such molecules, a trimer with asymmetric Mo[double bond, length as m-dash]O→Mo bridges crystallises. The complexes can catalyse epoxidation of cis-cyclooctene and sulfoxidation of methyl-p-tolylsulfide, using tert-butyl hydroperoxide as oxidant.

Nanowires: a new pathway to nanotechnology-based applications.

The synthesis and the characterisation of silicon nanowires (SiNWs) have recently attracted great attention due to their potential applications in electronics and photonics. As yet, there are no practical uses of nanowires, except for research purposes, but certain properties and characteristics of nanowires look very promising for the future. Graphical abstractSemiconductor nanowires are attracting more and more interest for their applications in nanoscience and nanotechnology. The characteristic of the nanowires is their geometry with a diameter in the range of a few nanometers and a length far greater than their diameter. The structural defects often lead to mechanical defects. By reducing the number of defects per unit length, decreasing the lateral dimensions, crystalline nanowires are expected to be more resistant than the solid. Recently nanowires are attracting intense interest for solar energy conversion. In this review, we summarize the different methods of nanowires production and their applications. Special focus will be kept on silicon nanowires.

Effect of zinc on growth of preterm babies.

Zinc is being recognized increasingly as an important element in human growth, development and immunological function. It is probably the most intensely studied microelement in newborn nutrition. Zinc deficiency is common in young infants in the developing world and is associated with reduced immunocompetence and increased rates of serious disease. Preterm neonates are especially vulnerable because of preterm delivery and low birth weight. The preterm baby has very limited stored energy and needs an adequate supply of nutrient. Preterm infant have high zinc dietary requirements as 60% fetal zinc is acquired during third trimester of pregnancy. Low concentration of zinc was found in pre-term low birth weight babies in different studies. Studies showed that before supplementation serum zinc level in preterm low birth weight babies were 62+/-12.4 microgm/dl, 65 microgm/dl, 54+/-14.4 microgm/dl and after supplementation serum zinc level were 105.8+/-16.6 microgm/dl, 86.4+/-24.7 microgm/dl respectively. At the same time mean weight & length of supplementation and without supplementation group were 6084 gm vs. 5280 gm, 2779+/-638.7 gm vs. 2474.6+/-441.8 gm and length 23.7 cm vs. 21.4 cm, 46.49+/-2.6 cm vs. 44.1+/-2.8 cm respectively. So supplementation of zinc in preterm babies causes improved growth and development. Various reports showed beneficial effect of long supplement in early growth of pre-term babies. However long term follow up studies are needed to evaluate the beneficial effect of zinc supplementation on growth of preterm babies.

Serum zinc level in preterm low birth weight babies and its comparison between preterm AGA and preterm SGA babies.

Low birth weight (LBW) is a major child health problem in Bangladesh and continuing to great threat to child health and child survival in Bangladesh. LBW is a silent emergency but crisis is real and its persistence has profound and frightening impact on neonatal mortality. This observational study was conducted in Dhaka Shishu Hospital, Dhaka, Bangladesh during July 2004 to June 2005. Serum zinc levels were estimated between two groups: group-I preterm AGA (n=50), group II preterm SGA (n=50) babies. Blood samples were collected from the study population in neonatal unit and serum zinc levels were measured by flame atomic absorption spectrophotometry in Atomic Energy Center, Dhaka, Bangladesh. Observed data were made comparison among groups by Students 't' test. It was observed serum zinc level (60.2+/-15.2) in group I and (62.1+/-12.4) in group II. Serum zinc level was in lower limit of normal range in both groups with more lower level in preterm AGA babies but their difference was not statistically significant (p>0.05). So zinc supplementation may enhance the growth of preterm LBW babies in their early months of lives.

Raman and near-field spectroscopic study on localized surface plasmon excitation from the 2D nanostructure of gold nanoparticles.

We have studied electromagnetic field on the surface of two-dimensional nanostructure of gold nanoparticles through two-photon-induced photoluminescence images by using scanning near-field optical microscope and far-field surface-enhanced Raman scattering measurements. The near-field two-photon-induced photoluminescence image shows that strong inhomogeneous enhancement in two-photon-induced photoluminescence occurs over the two-dimensional nanostructure, representing localized surface plasmon excitations. The results suggest that the local structure of the two-dimensional nanostructure influences the distribution of localized surface plasmon excitation.

Levels of blood and urine chemicals associated with longer duration of having arsenicosis in Bangladesh.

Arsenicosis is presently one of the significant public health problems in Bangladesh. Employing household screening of over 3.6 million people living in 6 arsenic-affected Upzilas of Bangladesh, 1,503 arsenicosis patients were identified at first and then blood and urine were collected from some of them and analyzed through laboratory techniques. As the relation between blood and urine chemicals with duration of having arsenicosis (DHA) is not clear, this study presented all findings by shorter versus longer DHA. Complications namely chronic bronchitis, conjunctivitis/congestions, weakness, and wasting were common, with relatively higher rates in longer group. Logistic regression analysis adjusted for age, sex, education, smoking, duration of drinking tube-well water, and whether any arsenicosis patients were in the family-indicated higher odds ratio (OR) of longer DHA (LDHA) in 3rd tertile with respect to GOT (OR = 2.12; 95%CI: 1.09-4.13), and blood glucose (OR = 2.00; 95%CI: 1.07-3.72) than 1st tertile. The OR of LDHA was significantly lower (OR = 0.48; 95%CI: 0.25-0.93) in 3rd tertile for triglycerides compared with 1st tertile. Albumin/globulin (A/G) ratio of 2nd tertile showed significantly lower OR of LDHA (OR=0.51; 95%CI: 0.28-0.95) than 1st tertile. Further epidemiological investigations based on a large sample, through cohort or case control studies, may be useful for validating and generalizing the results in Bangladesh.

Manifestation of arsenicosis patients and factors determining the duration of arsenic symptoms in Bangladesh.

This study analyzed a total of 1482 arsenicosis patients living in 6 of 496 upzilas (sub-districts) of Bangladesh, who were identified through household screening and then confirmed by a trained medical team headed by medical officer. Melanosis was common (97%) among them but about two-thirds (68.7%) of the patients were suffering from keratosis. Average age was 36 years and average duration of arsenic symptoms was 3 (median) years. About 50% of the patients had been drinking tubewell water more than 24 years. Melanosis was significantly associated with younger patients (P=0.031), shallower tubewell (P=0.005), and complication of conjunctivitis (P<0.001). Keratosis was also significantly associated with older age (P=0.022), shallower tubewell (P<0.001), complication of conjunctivitis (P<0.001), bronchitis (P<0.001), loss of appetite (P<0.001), and wasting (P<0.001). Duration of arsenic symptoms was significantly associated with older age (P<0.001), male (P=0.002), married (P<0.001), smoking (P=0.002), longer duration of consuming tubewell water (P<0.001), complication of conjunctivitis (P=0.002), loss of appetite (P<0.001), wasting (P=0.006), and social problem faced having arsenicosis (P=0.040). Multivariate odds ratio (OR) and 95% confidence interval (CI) indicated that keratosis (OR=2.00; 95% CI: 1.56-2.56) was significantly associated with longer duration of arsenic symptoms; loss of appetite (OR=1.40; 95% CI: 1.12-1.74) was a significant complication for longer duration. Similarly smoking (OR=1.33; 95% CI: 1.06-1.68) was positively associated with longer duration of arsenic symptom. These findings will help the policy makers of Bangladesh to understand about the factors that may affect the severity condition of the patients through prolongation of arsenic symptoms.

Resistance pattern of bacteria isolated from acute respiratory tract infection (ARI) cases.

Out of 350 acute respiratory tract infection (ARI) patients 110 (31.4%) were positive on culture. Among then (35.5%) yielded from upper respiratory tract infection (URI) and 64.5% yielded from lower respiratory tract infection (LRI). Predominant bacterial isolates from URI were Staph aureus (12.4%) and Strepto. pyogen (9.8%) whereas predominant agent from LRI were Strepto. pneumoniae (14.7%) and Haemophilus influenzae (8.6%). Capsular typing by polymerase chain reaction (PCR) and type specific antisera revealed that 64.7% of the isolates were type-b and rest were non-b. The most frequent resistance pattern of H. influenzae was found resistant to penicillin-ampicillin (64.7%) followed by SMX-TMP (14.7%) and tetracycline (5.9%). Among penicillin-ampicillin resistant strains, 81.8% were beta lectamase positive and 18.2% were beta lectamase negative. Among beta lectamase positive strains 66.7% were capsular type-b and 33.3% were non-b, had MICS < or = 8 microgram/ml. and < or = 4 microgram/ml. respectively. 5.9% strains of Strepto. pneumoniae was found resistant to SMX-TMP, 5.9% to penicillin-ampicillin and 2.9% to cephalexin. Common resistance pattern of Staph aureus was penicillin-ampicillin (60%), SMX-TMP (37.2%) and tetracycline-erythromycine-cephalexin (11.4%). Strepto. pyogen was found resistant to tetracycline in 12.2% cases and to SMX-TMP in 8.3% cases.