Carbon−Phosphorus Bond Activation of Tri(2-thienyl)phosphine at Dirhenium and Dimanganese Centers

Reaction of [Re2(CO)9(NCMe)] with tri(2-thienyl)phosphine (PTh3) in refluxing cyclohexane affords three substituted dirhenium complexes: [Re2(CO)9(PTh3)] (1), [Re2(CO)8(NCMe)(PTh3)] (2), and [Re2(CO)8(PTh3)2] (3). Complex 2 was also obtained from the room-temperature reaction of [Re2(CO)8(NCMe)2] with PTh3 and is an unusual example in which the acetonitrile and phosphine ligands are coordinated to the same rhenium atom. Thermolysis of 1 and 3 in refluxing xylene affords [Re2(CO)8(μ-PTh2)(μ-η1:κ1-C4H3S)] (4) and [Re2(CO)7(PTh3)(μ-PTh2)(μ-H)] (5), respectively, both resulting from carbon−phosphorus bond cleavage of a coordinated PTh3 ligand. Reaction of [Re2(CO)10] and PTh3 in refluxing xylene gives a complex mixture of products. These products include 3−5, two further binuclear products, [Re2(CO)7(PTh3)(μ-PTh2)(μ-η1:κ1-C4H3S)] (6) and [Re2(CO)7(μ-κ1:κ2-Th2PC4H2SPTh)(μ-η1:κ1-C4H3S)] (7), and the mononuclear hydrides [ReH(CO)4(PTh3)] (8) and trans-[ReH(CO)3(PTh3)2] (9). Binuclear 6 is structurally similar to 4 and can be obtained from reaction of the latter with 1 equiv of PTh3. Formation of 7 involves a series of rearrangements resulting in the formation of a unique new diphosphine ligand, Th2PC4H2SPTh. Reaction of [Mn2(CO)10] with PTh3 in refluxing toluene affords the phosphine-substituted product [Mn2(CO)9(PTh3)] (10) and two carbon−phosphorus bond cleavage products, [Mn2(CO)6(μ-PTh2)(μ-η1:η5-C4H3S)] (11) and [Mn2(CO)5(PTh3)(μ-PTh2)(μ-η1:η5-C4H3S)] (12). Both 11 and 12 contain a bridging thienyl ligand that is bonded to one manganese atom in a η5-fashion. The molecular structures of eight of these new complexes were established by single-crystal X-ray diffraction studies, allowing a detailed analysis of the disposition of the coordinated ligands

A study on biogas technology in Bangladesh

The anaerobic digestive method has the advantage of low or no energy consumption in operation, less sludge left and small land occupancy. The use of anaerobic digestive method for the treatment of various organic wastes from domestic, commercial, industrial and agricultural sources generates biogas (a mixture of methane and carbon dioxide, which is being used as energy) and preserves the nutrients which are recycled back to the agricultural land in the form of slurry. The relevance of biogas technology in Bangladesh lies in the fact that it makes the best possible utilization of various organic wastes (which have no or little economic value at the present moment) as a renewable source of clean energy in the rural and semi-urban areas. The implementation of biogas technology has a great potential of mitigating several problems related to ecological imbalance, minimise crucial fuel demand, improve hygiene and health and therefore, there is an overall improvement in quality of life in rural and semi-urban areas. This paper is aimed to highlight the potential of biogas technology in the Bangladesh context, and to identify the problems and research needs in this field

Diagnosed hematological malignancies in Bangladesh - a retrospective analysis of over 5000 cases from 10 specialized hospitals

Background The global burden from cancer is rising, especially as low-income countries like Bangladesh observe rapid aging. So far, there are no comprehensive descriptions reporting diagnosed cancer group that include hematological malignancies in Bangladesh. Methods This was a multi-center hospital-based retrospective descriptive study of over 5000 confirmed hematological cancer cases in between January 2008 to December 2012. Morphological typing was carried out using the “French American British” classification system. Results A total of 5013 patients aged between 2 to 90 years had been diagnosed with malignant hematological disorders. A 69.2% were males (n = 3468) and 30.8% females (n = 1545), with a male to female ratio of 2.2:1. The overall median age at diagnosis was 42 years. Acute myeloid leukemia was most frequent (28.3%) with a median age of 35 years, followed by chronic myeloid leukemia with 18.2% (median age 40 years), non-Hodgkin lymphoma (16.9%; median age 48 years), acute lymphoblastic leukemia (14.1%; median age 27 years), multiple myeloma (10.5%; median age 55 years), myelodysplastic syndromes (4.5%; median age 57 years) and Hodgkin’s lymphoma (3.9%; median age 36 years). The least common was chronic lymphocytic leukemia (3.7%; median age 60 years). Below the age of 20 years, acute lymphoblastic leukemia was predominant (37.3%), followed by acute myeloid leukemia (34%). Chronic lymphocytic leukemia and multiple myeloma had mostly occurred among older patients, aged 50-over. Conclusions For the first time, our study presents the pattern and distribution of diagnosed hematological cancers in Bangladesh. It shows differences in population distributions as compared to other settings with possibly a lower presence of non-Hodgkin lymphoma. There might be under-reporting of affected women. Further studies are necessary on the epidemiology, genetics and potential environmental risk factors within this rapidly aging country

Methanolic extracts of Withania somnifera leaves, fruits and roots possess antioxidant properties and antibacterial activities

Abstract Background Withania somnifera, also known as ashwagandha, is an important herb in ayurvedic and indigenous medical systems. The present study was designed to evaluate the antioxidant and antibacterial activities of an 80% aqueous methanolic extract of W. somnifera roots (WSREt), fruits (WSFEt) and leaves (WSLEt). Methods Several assays were performed to determine the antioxidant properties of this herb including 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) scavenging activity, ferric reducing antioxidant power (FRAP), ferrous chelation and inhibition of β-carotene bleaching. Results The values for DPPH, FRAP, ferrous chelation and inhibition of β carotene bleaching for the three types of extracts ranged from 101.73-801.93 μg/ml, 2.26-3.29 mM Fe/kg, 0.22-0.65 mg/ml and 69.87-79.67%, respectively, indicating that W. somnifera, particularly the leaves, possesses significant antioxidant properties. The mean ascorbic acid content was 20.60-62.60 mg/100 g, and the mean anthocyanin content was 2.86-12.50 mg/100 g. Antibacterial activities were measured using the agar well diffusion method and five pathogenic Gram-negative bacteria: Escherichia coli, Salmonella typhi, Citrobacter freundii, Pseudomonas aeruginosa and Klebsiella pneumoniae. The leaf extracts displayed the highest activity against S. typhi (32.00 ± 0.75 mm zone of inhibition), whereas the lowest activity was against K. pneumoniae (19.00 ± 1.48 mm zone of inhibition). The lowest minimum inhibitory concentration value was 6.25 mg/ml, which was against S. typhi, followed by 12.5 mg/ml against E. coli. Conclusion In addition to its antioxidant properties, W. somnifer a exhibited significant antibacterial activities against Gram-negative bacteria, particularly S. typhi. </jats:sec

Nutrition-related factors and binge eating behaviour in a sample of Malaysian University students

Binge eating (BE) behaviour is associated with obesity and eating disorders. This cross-sectional study investigates BE behaviour and its relationship with nutrition-related factors among university students. A total of 170 (69% females) university students in Malaysia aged 19 to 24 years participated in this study. BE behaviour was assessed with the use of Binge Eating Scale (BES) questionnaire. Socio-demographic background and nutritional status (anthropometric measurements, body mass index (BMI) and dietary intake) were also measured. BE behaviour reported by 10% percent of the participants. BE behaviour was associated with increased energy intake, elevated BMI and sex (Adjusted R2 = 0.116, p < 0.001). Differences in sex-specific factors in predicting the risk of BE behaviour were evident. In male participants, an increased in energy intake, elevated BMI and had a higher waist circumference associated with the risk of BE behaviour (Adjusted R2 = 0.411, p < 0.001). In female participants, only a higher waist circumference associated with BE behaviour (Adjusted R2 = 0.028, p < 0.05). The finding suggests that understanding sex-specific factors are necessary to prevent BE. These are the potential targets for tailored eating behaviour intervention among university students