Floating marine debris influx in the intertidal zone of offshore islands in Bangladesh: A case study of Manpura Island.

Marine Debris is all-pervading in the world's oceans. In this research, for the first time, Floating Marine Debris (FMD) accumulation in the intertidal zone of Manprua island, an offshore island of Bangladesh, is reported. The assessment has been done by integrating both physical investigations and questionnaire survey. The Study shows high debris density on the windward and river-facing sides of the island. The density of debris items in this area varies from 550,000 to 60,000 items per km2 (8.5 to 0.08 g/m2) for transect samples during low tide and 350,000 to 60,000 items per km2 (5.76 to 1.20 g/m2) for net samples during high tide. However, the most damaging debris items are uprooted trees and water hyacinths because they hinder fishing activities. This study provides baseline information on FMD in the Meghna Estuary, which can be used as a reference for sustainable monitoring and management of marine pollution.

Environmental surveillance of commonly-grown vegetables for investigating potential lead and chromium contamination intensification in Bangladesh.

With regard to previously reported Lead (Pb) and Chromium (Cr) contamination in egg, a semi-quantitative assessment of the general environment of Bangladesh is carried out through nation-wide sampling of commonly grown and consumed vegetables. Five vegetables, namely, White Potato (Solanum tuberosum), Green Cabbage (Brassica oleracea capitata var. alba L.), Red Spinach (Amaranthus dubius), White Radish (Raphanus sativus var. longipinnatus), and Green Bean (Phaseolus vulgaris) were selected for sampling from all 64 Districts of the country as per their availability during the sampling season. This results in a collection of 292 samples. Due to the necessity of incorporating a wide spectrum of vegetable types (e.g. tuber, brassica, leafy, root, and fruiting vegetables) as well as the need for including the geographic expanse of the whole country, replicates were not accommodated in the study, hence, the study being semi-quantitative in nature. The results do not substantiate evidence of public health risk due to Cr yet, with only 0.69 % of the samples found contaminated with Cr. Pb contamination (concentrations above a health-based guidance value) is found in 29.47 % of the samples; and together with the insight of such contamination likely being non-point origin, communicates on potential public health risk due to Pb as residual effects of extensive ambient atmospheric Pb pollution in recent history of the country. For the purpose of comparison, Cadmium (Cd) contents of the samples are also analyzed. Although there is no extensive Cd pollution history/source in the country, the likely point-source nature of Cd contamination found in 17.83 % of the samples indicates the scope of managing any existing contamination source by directing efforts into the potential point-sources.

Anti-diabetic effects of the acetone fraction of Senna singueana stem bark in a type 2 diabetes rat model.

ETHNOPHARMACOLOGICAL RELEVANCE: Senna singueana is currently used in the traditional treatment of diabetes mellitus in Nigeria. The present study examined the anti-diabetic activity of the Senna singueana acetone fraction (SSAF) of stem bark in a type 2 diabetes (T2D) rat model. MATERIALS AND METHODS: Crude ethyl acetate extract of the Senna singueana stem bark was fractionated with various solvents and the acetone fraction was selected for in vivo studies based on the high α-glucosidase and α-amylase inhibitory activities. In the in vivo study, male Sprague-Dawley rats were induced with T2D and treated with the SSAF at 150 and 300 mg/kg body weight. Several T2D-related parameters were measured in the study. RESULTS: After 4 weeks of intervention, non-fasting blood glucose concentrations were significantly decreased and the glucose tolerance ability was significantly improved in the SSAF treated groups compared to the diabetic control group. Serum insulin concentrations, pancreatic ß-cell function (HOMA-ß) and liver glycogen were significantly (P<0.05) increased while serum alanine transaminase, alkaline phosphatase and urea were significantly decreased in the SSAF treated diabetic rats compared to the diabetic control group. Though insignificantly (P>0.05), other T2D-induced abnormalities such as food and fluid intake, body weight, serum lipids, serum fructosamine level and peripheral insulin resistance (HOMA-IR) were also partially ameliorated by the SSAF treatment. CONCLUSION: Data of this study suggest that orally administered SSAF could ameliorate most of the T2D-induced abnormalities in a T2D model of rats.

In vivo detection of cortical optical changes associated with seizure activity with optical coherence tomography.

The most common technology for seizure detection is with electroencephalography (EEG), which has low spatial resolution and minimal depth discrimination. Optical techniques using near-infrared (NIR) light have been used to improve upon EEG technology and previous research has suggested that optical changes, specifically changes in near-infrared optical scattering, may precede EEG seizure onset in in vivo models. Optical coherence tomography (OCT) is a high resolution, minimally invasive imaging technique, which can produce depth resolved cross-sectional images. In this study, OCT was used to detect changes in optical properties of cortical tissue in vivo in mice before and during the induction of generalized seizure activity. We demonstrated that a significant decrease (P < 0.001) in backscattered intensity during seizure progression can be detected before the onset of observable manifestations of generalized (stage-5) seizures. These results indicate the feasibility of minimally-invasive optical detection of seizures with OCT.

Thinned-skull cortical window technique for in vivo optical coherence tomography imaging.

Optical coherence tomography (OCT) is a biomedical imaging technique with high spatial-temporal resolution. With its minimally invasive approach OCT has been used extensively in ophthalmology, dermatology, and gastroenterology. Using a thinned-skull cortical window (TSCW), we employ spectral-domain OCT (SD-OCT) modality as a tool to image the cortex in vivo. Commonly, an opened-skull has been used for neuro-imaging as it provides more versatility, however, a TSCW approach is less invasive and is an effective mean for long term imaging in neuropathology studies. Here, we present a method of creating a TSCW in a mouse model for in vivo OCT imaging of the cerebral cortex.

GPU accelerated real-time multi-functional spectral-domain optical coherence tomography system at 1300 nm.

We present a GPU accelerated multi-functional spectral domain optical coherence tomography system at 1300 nm. The system is capable of real-time processing and display of every intensity image, comprised of 512 pixels by 2048 A-lines acquired at 20 frames per second. The update rate for all four images with size of 512 pixels by 2048 A-lines simultaneously (intensity, phase retardation, flow and en face view) is approximately 10 frames per second. Additionally, we report for the first time the characterization of phase retardation and diattenuation by a sample comprised of a stacked set of polarizing film and wave plate. The calculated optic axis orientation, phase retardation and diattenuation match well with expected values. The speed of each facet of the multi-functional OCT CPU-GPU hybrid acquisition system, intensity, phase retardation, and flow, were separately demonstrated by imaging a horseshoe crab lateral compound eye, a non-uniformly heated chicken muscle, and a microfluidic device. A mouse brain with thin skull preparation was imaged in vivo and demonstrated the capability of the system for live multi-functional OCT visualization.

Extracting structural features of rat sciatic nerve using polarization-sensitive spectral domain optical coherence tomography.

We present spectral domain polarization-sensitive optical coherence tomography (SD PS-OCT) imaging of peripheral nerves. Structural and polarization-sensitive OCT imaging of uninjured rat sciatic nerves was evaluated both qualitatively and quantitatively. OCT and its functional extension, PS-OCT, were used to image sciatic nerve structure with clear delineation of the nerve boundaries to muscle and adipose tissues. A long-known optical effect, bands of Fontana, was also observed. Postprocessing analysis of these images provided significant quantitative information, such as epineurium thickness, estimates of extinction coefficient and birefringence of nerve and muscle tissue, frequency of bands of Fontana at different stretch levels of nerve, and change in average birefringence of nerve under stretched condition. We demonstrate that PS-OCT combined with regular-intensity OCT (compared with OCT alone) allows for a clearer determination of the inner and outer boundaries of the epineurium and distinction of nerve and muscle based on their birefringence pattern. PS-OCT measurements on normal nerves show that the technique is promising for studies on peripheral nerve injury.

Calcium signaling in the islets.

Easy access to rodent islets and insulinoma cells and the ease of measuring Ca(2+) by fluorescent indicators have resulted in an overflow of data that have clarified minute details of Ca(2+) signaling in the rodent islets. Our understanding of the mechanisms and the roles of Ca(2+) signaling in the human islets, under physiological conditions, has been hugely influenced by uncritical extrapolation of the rodent data obtained under suboptimal experimental conditions. More recently, electrophysiological and Ca(2+) studies have elucidated the ion channel repertoire relevant for Ca(2+) signaling in the human islets and have examined their relative importance. Many new channels belonging to the transient receptor potential (TRP) family are present in the beta-cells. Ryanodine receptors, nicotinic acid adenine dinucleotide phosphate channel, and Ca(2+)-induced Ca(2+) release add new dimension to the complexity of Ca(2+) signaling in the human beta-cells. A lot more needs to be learnt about the roles of these new channels and CICR, not because that will be easy but because that will be difficult. Much de-learning will also be needed. Human beta-cells do not have a resting state in the normal human body even under physiological fasting conditions. Their membrane potential under physiologically relevant resting conditions is approximately -50 mV. Biphasic insulin secretion is an experimental epiphenomenon unrelated to the physiological pulsatile insulin secretion into the portal vein in the human body. Human islets show a wide variety of electrical activities and patterns of [Ca(2+)](i) changes, whose roles in mediating pulsatile secretion of insulin into the portal vein remain questionable. Future studies will hopefully be directed toward a better understanding of Ca(2+) signaling in the human islets in the context of the pathogenesis and treatment of human diabetes.

Effects of dietary onion (Allium cepa L.) in a high-fat diet streptozotocin-induced diabetes rodent model.

BACKGROUND/AIMS: The present study was conducted to investigate the effects of two dietary doses of freeze-dried onion powder on diabetes-related symptoms in a high-fat (HF) diet streptozotocin (STZ)-induced diabetes rat model. METHODS: Five-week-old male Sprague-Dawley rats were fed a HF diet for 2 weeks and then randomly divided into 4 groups as follows: HF control (HFC), diabetic control (DBC), onion low (ONL; 0.5%) and onion high (ONH; 2.0%). Diabetes was induced by an intraperitoneal injection of STZ (40 mg/kg body weight) in all groups except the HFC group. RESULTS: After 4 weeks on the experimental diets, fasting blood glucose levels for both onion-fed groups were higher than in the DBC and HFC groups, albeit only significantly so (p < 0.05) in the ONL group. Serum insulin concentrations and insulin resistance were dose-dependently increased (however, not significantly so) in the onion-fed groups compared to the DBC group. Pancreatic beta-cell function and liver glycogen concentrations were nonsignificantly higher in the DBC and ONH groups compared to the ONL group. Additionally, the ONH group had significantly higher lipid concentrations (except for high-density lipoprotein cholesterol) compared to all other groups. The ONL group showed a similar hyperlipidemic trend, however to a lesser extent, with only triglycerides significantly differing from those of the DBC and HFC groups. CONCLUSION: The results suggest that the HF onion diet may increase insulin secretion and consequently insulin resistance in a dose-dependent manner, resulting in a worsened hyperglycemic and hyperlipidemic diabetic state. We conclude that higher dietary fat may impair the antidiabetic effects of dietary onion intake as has been previously reported.

A comparison of regional variations of fertility in Bangladesh.

This study, based on the 2004 Bangladesh Demographic and Health Survey (BDHS), examines the extent to which regional variations of reproductive behavior are explained by inherent demographic, socioeconomic, and programmatic differences among regions. This article also attempts to investigate the impact of four intermediate fertility variables; namely marriage, contraception, lactational infecundability, and induced abortion, on fertility among different regions in Bangladesh. The contribution of proximate variables was observed through the decomposition of the total fertility rate (TFR) into proximate components. The results indicate that contraception is the highest fertility reducing factor in all the regions.

Convenient method of synthesizing 3-ethoxycarbonyl indoles.

We have developed a convenient two-step procedure for the synthesis of 3-ethoxycarbonyl indoles from commercially available materials. The two-step procedure involves the synthesis of 2-aryl-3-hydroxypropenoic acid ester, followed by a catalytic reduction. This method is efficient, simple, and selective.

Acid-catalyzed reactions of aromatic aldehydes with ethyl diazoacetate: an investigation on the synthesis of 3-hydroxy-2-arylacrylic acid ethyl esters.

Several commercial Lewis acids, including those of the Bronsted type, specifically HBF(4).OEt(2), are able to catalyze the reaction between aromatic aldehydes and ethyl diazoacetate to produce 3-hydroxy-2-arylacrylic acid ethyl esters and 3-oxo-3-arylpropanoic acid ethyl esters. Reactions catalyzed by the iron Lewis acid [(eta(5)-C(5)H(5))Fe(+)(CO)(2)(THF)]BF(4)(-) (i.e., 1) have the best yields and greatest ratio of 3-hydroxy-2-arylacrylic acid ethyl ester. The product distribution of 1 is not affected in the presence of Proton Sponge, but is dependent on temperature and the nature of the substrate aldehyde, whereas the activity of HBF(4).OEt(2) is affected by the presence of Proton Sponge and is reactive at temperatures as low as -78 degrees C. Consequently, both 1 and HBF(4).OEt(2) are valuable catalysts in producing important 3-hydroxy-2-arylacrylic acid ethyl esters as precursors to biologically active compounds.

Effects of minerals on resistance of Bacillus subtilis spores to heat and hydrostatic pressure.

Among Bacillus subtilis IFO13722 spores sporulated at 30, 37, and 44 degrees C, those sporulated at 30 degrees C had the highest resistance to treatments with high hydrostatic pressure (100 to 300 MPa, 55 degrees C, 30 min). Pressure resistance increased after demineralization of the spores and decreased after remineralization of the spores with Ca(2+) or Mg(2+), whereas the resistance did not change when spores were remineralized with Mn(2+) or K(+), suggesting that former two divalent ions were involved in the activation of cortex-lytic enzymes during germination.