Effects of gamma radiation on nutritional and microbial quality of Pampus chinensis (Euphrasen 1788)

To evaluate the efficiency of gamma radiation in combination with low temperature Chinese pomfret, Pampus chinensis were preserved by the treatment of different doses of gamma radiation (3, 5 and 8 KGy) at freezing temperature (-20°C) during 90 days of storage period. Quality assessments for fish were carried out at an interval of 15 days during the storage period. Quality assessments were done by organoleptic, chemical (Total Volatile Nitrogen, TVN and Trimethylamine, TMA) and microbiological (Total Bacterial Count, TBC and Total Mould Count, TMC) evaluation. From the analysis of all parameters, maximum shelf-life was observed for irradiated (8 KGy) sample. It remained acceptable up to 75 days and that was the highest duration among 4 types of samples

Effects of irradiation on formaldehyde concentration and nutritional changes of formalin treated fish, Pampus chinensis

Formaldehyde is a very reactive compound capable of interacting with many functional groups of proteins including intermolecular and intramolecular cross-links of the molecules. The formation of cross-linking bonds may induce conformational change in proteins that favor further interaction of functional and hydrophobic groups. Formaldehyde which has been using illegally as a chemical preservative by some fish traders in our country. A study was carried out to determine the effects of irradiation (1.5 KGy) on formaldehyde concentration and nutritional (protein and lipid) changes of formalin (37% formaldehyde) treated fish (fresh) samples and found that the concentration of formaldehyde both in treated samples (0.37% formalin and 0.37% formalin with 1.5 KGy irradiation) were 37.0 µg/gm and 36.75 µg/gm. On the other hand, the amount of protein and lipid in treated samples before radiation (14.56% and 3.49%) and after radiation (14.15% and 3.25%). That means, radiation has no effect on the change of protein, lipid and formaldehyde

Momentum-Resolved Inelastic X-ray Scattering as a Novel Tool to Study Charge Gap in Complex Insulators

We report particle-hole pair excitations in a cuprate insulator in the intermediate regimes of momentum-transfers using high energy inelastic x-ray scattering. The excitation spectra show dispersive features near the Mott edge which shed light on the momentum structure of the upper Hubbard band in cuprates. We briefly discuss the potential use of such a technique to study the momentum dependence of unoccupied bands and q-dependent charge fluctuations in complex insulators.Comment: 3 pages, 2 figures, Revise

Nature of Correlated Motion of Electrons in the Parent Cobaltate Superconductors

Recently discovered class of cobaltate superconductors (Na0.3CoO2.nH2O) is a novel realization of interacting quantum electron systems in a triangular network with low-energy degrees of freedom. We employ angle-resolved photoemission spectroscopy to uncover the nature of microscopic electron motion in the parent superconductors for the first time. Results reveal a large hole-like Fermi surface (consistent with Luttinger theorem) generated by the crossing of super-heavy quasiparticles. The measured quasiparticle parameters collectively suggest a two orders of magnitude departure from the conventional Bardeen-Cooper-Schrieffer electron dynamics paradigm and unveils cobaltates as a rather hidden class of relatively high temperature superconductors.Comment: 5 pages, 4 figures, 1 tabl

Change in economic burden of diarrhoea in children under-five in Bangladesh: 2007 vs. 2018

Background: In Bangladesh, diarrhoea in children under-five is a major public health problem with cost implications. Although under-five diarrhoea mortality and morbidity have declined from 2007 to 2018, change in the economic burden is unknown. This study determined the change in the societal economic burden of under-five diarrhoea in Bangladesh comparing 2007 to 2018. Methods: A prevalence-based, retrospective cost analysis was conducted from a societal perspective, including costs to households, providers, and economic loss from premature deaths. Data were obtained from the previous cost of illness studies, government reports, and international databases. Direct costs for treatment were estimated by the bottom-up costing approach. Indirect costs on the loss of productivity of caretakers and loss from premature deaths were calculated by the human capital method. Total costs were presented in both local currency (Bangladeshi Taka (BDT)) and US dollars (US$)) in 2018 price. Sensitivity analyses were conducted to assess the robustness of the input parameters. Results: A 36.4$1 209 million (95% CI = 1066 million-1299 million) for 2007 and US$769 million (95% CI = 484 million-873 million) for 2018. Economic loss from premature deaths imposed the highest costs (2007 = 66%, 2018 = 66% of all) followed by indirect costs on the loss of productivity of caretakers (2007 = 21%, 2018 = 26%) and direct medical costs (2007 = 13%, 2018 = 8%). Conclusions: Societal costs from diarrhoeal diseases were reduced from 2007 to 2018 in Bangladesh. However, the economic burden was equivalent to 0.29% of country’s gross domestic product in 2018 and remains a challenge. The major contributor to the costs was premature mortality from diarrhoeal diseases. Premature deaths are still prevalent though they to a large extent are avoidable. To further limit the economic burden, under-five diarrhoea mortality and morbidity reduction should be accelerated

Excitons in Mott insulators

Motivated by recent Raman and resonant inelastic X-ray scattering experiments performed for Mott insulators, which suggest formation of excitons in these systems, we present a theory of exciton formation in the upper Hubbard band. The analysis based on the spin polaron approach is performed in the framework of an effective t-J model for the subspace of states with one doubly occupied site. Our results confirm the existence of excitons and bear qualitative resemblance to experimental data despite some simplifications in our approach. They prove that the basic underlying mechanismof exciton formation is the same as that which gives rise to binding of holes in weakly doped antiferromagnets.Comment: 4 pages, 1 figur

OPTIMIZATION OF COMPRESSION MOULDING PARAMETERS FOR MULTI FILLER POLYMER COMPOSITE USING TAGUCHI METHOD

Polymer Electrolyte Membrane Fuel Cells (PEMFC) performance depends on the properties of bipolar plates (BP). In order to produce the best performance of BP, compression moulding parameters need to be optimized. This study determined the compression moulding parameters of Graphite (G) / Carbon Black (CB) / Carbon Fiber (CF) / Polypropylene (PP) composites using Taguchi method (TM) in order to optimize the properties of BP plate. L9 Orthogonal Array with four factors and three levels was chosen as a design of experiment for G/CB/CF/PP composition with a weight percentage of 50/25/5/20. The factors selected for this study were heating temperature, load, preheating pressing time and pressing time. The electrical conductivity value of each sample was analyzed by signal to noise ratio using TM with the larger-the-better condition in order to determine the optimum parameters. Confirmation experiment was conducted to validate the optimum parameters obtained from the TM. The electrical conductivity result of G/CB/CF/PP composites for confirmation experiment was 393.49 S/cm and it was higher than nine trials and the TM predicted value. Hence, the optimum parameters of compression moulding can be obtained using TM to improve the electrical conductivity of G/CB/CF/PP composites. TM is an effective way to get the optimal moulding parameters for G/CB/CF/PP composites and is very useful to fabricate bipolar plate for PEMFC

Nonresonant inelastic light scattering in the Hubbard model

Inelastic light scattering from electrons is a symmetry-selective probe of the charge dynamics within correlated materials. Many measurements have been made on correlated insulators, and recent exact solutions in large dimensions explain a number of anomalous features found in experiments. Here we focus on the correlated metal, as described by the Hubbard model away from half filling. We can determine the B1g Raman response and the inelastic X-ray scattering along the Brillouin zone diagonal exactly in the large dimensional limit. We find a number of interesting features in the light scattering response which should be able to be seen in correlated metals such as the heavy fermions.Comment: 9 pages, 7 figures, typeset with ReVTe

From Fractional Chern Insulators to a Fractional Quantum Spin Hall Effect

We investigate the algebraic structure of flat energy bands a partial filling of which may give rise to a fractional quantum anomalous Hall effect (or a fractional Chern insulator) and a fractional quantum spin Hall effect. Both effects arise in the case of a sufficiently flat energy band as well as a roughly flat and homogeneous Berry curvature, such that the global Chern number, which is a topological invariant, may be associated with a local non-commutative geometry. This geometry is similar to the more familiar situation of the fractional quantum Hall effect in two-dimensional electron systems in a strong magnetic field.Comment: 8 pages, 3 figure; published version with labels in Figs. 2 and 3 correcte