Policy working paper : dynamic agribusiness-focused aquaculture for poverty reduction and economic growth in Bangladesh

Aquaculture development, Bangladesh,

Study of the aldopentoses and fucose in human urine by thin-layer chromatography

• 1. The thesis describes an investigation into the presence and quantities of four free, monosaccharides, L- arabinose, D-xylose, D-ribose and (presumably -) fucose in the urine of healthy human subjects and of patients suffering from renal failure. • 2. Two new quantitative analytical procedures based on one - dimensional thin-layer chromatography have been devised whereby it has become possible for the first time rapidly (3 h) to separate and measure at microgram levels, arabinose, ribose, xylose and fucose from the numerous other sugars present in urine from human subjects. On thin -layers of Kieselguhr G buffered with sodium acetate (acetate plate), arabinose and ribose are measured. On thin-layers of Kieselguhr G buffered with sodium dihydrogen phosphate (phosphate plate), fucose is determined. Xylose is measured by difference between ribose on an acetate plate and xylose plus ribose on a phosphate plate. Previously, only one complicated technique, occupying 5 days for the paper chromatography was available (Date, 1958a, 1958b, 1958c and 1966). • 3. The spraying reagents used to colour the sugar spots can detect qualitatively to the lowest limit of 0.5 μg of each sugar on the devised t.l.c. systems. The new PABA reagent visually distinguishes different sugar classes on the both t.l.c. systems. This reagent may be employed for quantitative measurements whereby linear relationship holds upto 30 μg for recovered colour of xylose from acetate plates and upto 80 μg for fucose from phosphate plates. Using the p-anisidine hydrochloride staining reagent, quantitative spectrophotometric determination of the extracted sugar spots is possible to the lowest limit of 2.5 μg for each sugar; linear relationship holds upto 8.0 dug for each sugar on either plate. • 4. Preparatory to chromatography, deionisation of urine samples is obligatory and accomplished by means of ion- exchange resins Amberlite IR-120 (H⁺) and Amberlite IRA -400 (acetate) using two glass columns in tandem. • 5. Specificity is conferred on the estimates by the comparable behaviours of the urinary aldopentoses and fucose so estimated and the authentic sugars on the thin-layer chromatograms. • 6. The separation of the sugars on the devised thin-layers is always reproducible. Quantitative reproducibilities (coefficient of variations) in a septuplicate analysis of the same urine sample show arabinose as 13.1%, xylose 15%, ribose 7.2% and fucose 10.2%. The mean±S.D. recoveries of 10-30 μg of arabinose, xylose, ribose and fucose added to the same urine samples in six experiments are 93%±5% (range 80-113%), 101%±41% (range 50-166 %), 95%±9% (range 85-110%) and 95%±14% (range 80-110%) respectively. • 7. All urine samples of six fasting healthy males and six fasting healthy females invariably contain arabinose, xylose, ribose and fucose. These sugars must presumably originate in endogenous processes. There is no significant difference in the excretion between the corresponding sugars in fasting state in two sexes. The mean fasting rates of excretion (,ig/min) of the sugars for the twelve subjects are 13.3±3.4 (arabinose), 8.5±1.9 (xylose), 5±1.5 (ribose) and 16.6±5.6 (fucose). • 8. Consuming an ample diet, free as far as possible from known sources of aldopentoses, healthy subjects at three different periods of the day excrete the sugars at rates unchanged from those in the fasting state. It is suggested that these sugars are excreted at constant rate independently of the urine volume. • 9. On diets potentially rich in aldopentoses, the subjects of (8) show increased rates of excretion of aldopentoses, mainly that of xylose and less so of arabinose. Noteworthy is the fact that rates of excretion of both ribose and fucose were not increased. • 10. Urines from all six patients with various forms of renal failure repeatedly show the same picture. Ribose is always excreted at the lower end of the normal range while arabinose, xylose and fucose, if detectable, are excreted only in unmeasurable amounts. • 11. The results are compared and discussed with other workers' findings. In so far as any reasonable suggestions can be made, the excretion of these four monosaccharides in health and in renal failure are discussed in the light of our knowledge of the somatic origins and metabolism of arabinose, ribose, xylose and fucose. The prospects of employing this technique and the measurements of these sugars in certain diseases are indicated

Terahertz quantum cascade laser with an X-valley-based injector

We present a novel terahertz (THz) quantum cascade laser (QCL) design where Γ-valley states are used for lasing transition and X-valley states—in particular, Xz-states—are used as injector subbands. Since the lasing states in our proposed structure are populated and depopulated mainly through the interface roughness assisted Γ-Xz electron scattering, we present a model to describe this intervalley carrier transport. In the injector region of the proposed THz QCL, we use quaternary AlGaAsP material to introduce tensile strain, which plays a crucial role in increasing the gain. To compensate the strain per period, we propose to grow the periodic heterostructure on a GaAs.94P.06 virtual substrate. To simulate the carrier transport, and hence calculate the gain and lasing performance of the proposed THz QCL, we use a simplified density matrix formalism that considers resonant tunneling, dephasing, and the important intersubband scattering mechanisms. Since electron temperature significantly varies from lattice temperature for QCLs, we take their difference into account using the kinetic energy balance (KEB) method. We show that the proposed structure is capable of lasing up to a maximum lattice temperature of ∼119 K at 4.8 THz. For future improvements of the device, we identify major performance-degrading factors of the proposed design

Role of Mothers\u27 Nutritional Knowledge, Nutritional Factors on the School Performance

A cross sectional study was carried out to investigate the effects of mothers\u27 nutritional knowledge, health and nutritional factors and socio-economic parameters on school performance among class five students of University Laboratory School, Dhaka. All of the eighty students were selected for this study. This study found there is a strong relationship between mother\u27s knowledge score and school performance. It was found that mothers\u27 knowledge score was responsible for 91.1 percent change in school performance. The mean BMI of the mothers was 20.44. We found that the school performance measured by class roll number of the students is significantly related with mothers BMI. There was an imperfect negative association between socio-economic parameters and school performance. But the relationship between the school performances with socio-economic parameters was strongly significant. This study also observed the relationship between Individual Dietary Diversity Score (IDDS) of respondent and marks achieved in class 4 final exam. It is alarming that consumption percentage were low for eggs (30) and milk and milk products (37.5), but majority of the students who consumed milk and milk products (63.3%) and eggs (66.7%) got the highest marks

Seipin oligomers can interact directly with AGPAT2 and lipin 1, physically scaffolding critical regulators of adipogenesis

This work was supported by a Merit Scholarship from the Islamic Development Bank (to M.M.U.T.), The Agency for Science, Technology and Research, Singapore (A*STAR) (M.F.M.S), the Medical Research Council (MRC) [NIRG GO800203 and Research Grant MR/L002620/1 (to J.J.R.), Program GrantG09000554 (to S.O.R)], The Wellcome Trust [078986/Z/06/Z (to S.O.R.)], the MRC Centre for Obesity and Related Metabolic Disorders (MRC-CORD) [GO600717] and the NIHR Comprehensive Biomedical Research Centre [CG50826].Peer reviewedPublisher PD