Exploring the possibility of enhancing the figure-of-merit ( >> 2) of Na0.74_{0.74}CoO2_{2}: A combined experimental and theoretical study

Search of new thermoelectric (TE) materials with high \textit{figure-of-merit} (ZT) is always inspired the researcher in TE field. Here, we present a combined experimental and theoretical study of TE properties of Na$_{0.74}$CoO$_{2}$ compound in high-temperature region. The experimental Seebeck coefficient (S) is found to vary from 64 to 118 $\mu$V/K in the temperature range $300-620$ K. The positive values of S are indicating the dominating p-type behaviour of the compound. The observed value of thermal conductivity ($\kappa$) is $\sim$ 2.2 W/m-K at 300 K. In the temperature region $300-430$ K, the value of $\kappa$ increases up to $\sim$ 2.6 W/m-K and then decreases slowly till 620 K with the corresponding value of $\sim$ 2.4 W/m-K. We have also carried out the theoretical calculations and the best matching between experimental and calculated values of transport properties are observed in spin-polarized calculation within DFT+\textit{U} by chosen \textit{U} = 4 eV. The maximum calculated value of ZT is found to be $\sim$ 0.67 at 1200 K for p-type conduction. Our computational study suggests that the possibility of n-type behaviour of the compound which can lead to a large value of ZT at higher temperature region. Electron doping of $\sim$ 5.1$\times$10$^{20}$ cm$^{-3}$ is expected to give rise the high ZT value of $\sim$ 2.7 at 1200 K. Using these temperature-dependent ZT values, we have calculated the maximum possible values of efficiency ($\eta$) of thermoelectric generator (TEG) made by p and n-type Na$_{0.74}$CoO$_{2}$. The present study suggests that one can get the efficiency of a TE cell as high as $\sim$ 11$\%$ when the cold and hot end temperature are fixed at 300 K and 1200 K, respectively. Such high values of ZT and efficiency suggest that Na$_{0.74}$CoO$_{2}$ can be used as a potential candidate for high-temperature TE applications

Experimental and computational approaches to study the high temperature thermoelectric properties of novel topological semimetal CoSi

Here, we study the thermoelectric properties of topological semimetal CoSi in the temperature range $300-800$ K by using combined experimental and density functional theory (DFT) based methods. CoSi is synthesized using arc melting technique and the Rietveld refinement gives the lattice parameters of a = b = c = 4.445 {\AA}. The measured values of Seebeck coefficient (S) shows the non-monotonic behaviour in the studied temperature range with the value of $\sim-$81 $\mu$V/K at room temperature. The $|S|$ first increases till 560 K ($\sim-$93 $\mu$V/K) and then decreases up to 800 K ($\sim-$84 $\mu$V/K) indicating the dominating n-type behaviour in the full temperature range. The electrical conductivity, $\sigma$ (thermal conductivity, $\kappa$) shows the monotonic decreasing (increasing) behaviour with the values of $\sim$5.2$\times 10^{5}$ (12.1 W/m-K) and $\sim$3.6$\times 10^{5}$ (14.2 W/m-K) $\Omega^{-1}m^{-1}$ at 300 K and 800 K, respectively. The $\kappa$ exhibits the temperature dependency as, $\kappa \propto T^{0.16}$. The DFT based Boltzmann transport theory is used to understand these behaviour. The multi-band electron and hole pockets appear to be mainly responsible for deciding the temperature dependent transport behaviour. Specifically, the decrease in the $|S|$ above 560 K and change in the slope of $\sigma$ around 450 K are due to the contribution of thermally generated charge carriers from the hole pockets. The temperature dependent relaxation time is computed which shows temperature dependency of $1/T^{0.35}$. Present study suggests that electronic band-structure obtained from DFT provides reasonably good estimate of the transport coefficients of CoSi in the high temperature region of $300-800$ K

A human MAP kinase interactome.

Mitogen-activated protein kinase (MAPK) pathways form the backbone of signal transduction in the mammalian cell. Here we applied a systematic experimental and computational approach to map 2,269 interactions between human MAPK-related proteins and other cellular machinery and to assemble these data into functional modules. Multiple lines of evidence including conservation with yeast supported a core network of 641 interactions. Using small interfering RNA knockdowns, we observed that approximately one-third of MAPK-interacting proteins modulated MAPK-mediated signaling. We uncovered the Na-H exchanger NHE1 as a potential MAPK scaffold, found links between HSP90 chaperones and MAPK pathways and identified MUC12 as the human analog to the yeast signaling mucin Msb2. This study makes available a large resource of MAPK interactions and clone libraries, and it illustrates a methodology for probing signaling networks based on functional refinement of experimentally derived protein-interaction maps

Hemobilia caused by a ruptured hepatic cyst: a case report

<p>Abstract</p> <p>Introduction</p> <p>Hemobilia is a rare cause of upper gastrointestinal bleeding. More than 50% of hemobilia cases are related to iatrogenic trauma from hepatobiliary procedures, and needle biopsy of the liver represents the most common cause. A minority of hemobilia cases are due to hepatobiliary disorders such as cholangitis, hepatobiliary cancers, choledocholithiasis, and vascular abnormalities in the liver. The classic presentation of hemobilia is the triad of right upper quadrant (biliary) pain, obstructive jaundice, and upper gastrointestinal bleeding. We report a rare case of hemobilia caused by a spontaneous hepatic cyst rupture, where our patient presented without the classical symptoms, in the absence of therapeutic or pathological coagulopathy, and in the absence of spontaneous or iatrogenic trauma.</p> <p>Case presentation</p> <p>A 91-year-old African-American woman was referred to our out-patient gastroenterology clinic for evaluation of mild epigastric pain and intermittent melena. An abdominal computed tomography scan was remarkable for multiple hepatic cysts. Esophagogastroduodenoscopy revealed multiple blood clots at the ampulla of Vater. Endoscopic retrograde cholangiopancreatography showed a single 18 mm-sized filling defect in the common hepatic duct wall at the junction of the right and left hepatic duct, adjacent to one of the hepatic cysts. The ruptured hepatic cyst communicated to the bile ducts and was the cause of hemobilia with an atypical clinical presentation.</p> <p>Conclusion</p> <p>Hemobilia is an infrequent cause of upper gastrointestinal bleeding and rarely occurs due to hepatic cyst rupture. To the best of our knowledge, this is only the second case report in the literature that describes hemobilia due to hepatic cyst rupture. However, it is the first case in the literature of hemobilia due to hepatic cyst rupture in the absence of iatrogenic or spontaneous trauma, and in the absence of a spontaneous or pathological coagulopathy.</p

Lower bounds on multiple sequence alignment using exact 3-way alignment

<p>Abstract</p> <p>Background</p> <p>Multiple sequence alignment is fundamental. Exponential growth in computation time appears to be inevitable when an optimal alignment is required for many sequences. Exact costs of optimum alignments are therefore rarely computed. Consequently much effort has been invested in algorithms for alignment that are heuristic, or explore a restricted class of solutions. These give an upper bound on the alignment cost, but it is equally important to determine the quality of the solution obtained. In the absence of an optimal alignment with which to compare, lower bounds may be calculated to assess the quality of the alignment. As more effort is invested in improving upper bounds (alignment algorithms), it is therefore important to improve lower bounds as well. Although numerous cost metrics can be used to determine the quality of an alignment, many are based on sum-of-pairs (SP) measures and their generalizations.</p> <p>Results</p> <p>Two standard and two new methods are considered for using exact 2-way and 3-way alignments to compute lower bounds on total SP alignment cost; one new method fares well with respect to accuracy, while the other reduces the computation time. The first employs exhaustive computation of exact 3-way alignments, while the second employs an efficient heuristic to compute a much smaller number of exact 3-way alignments. Calculating all 3-way alignments exactly and computing their average improves lower bounds on sum of SP cost in <it>v</it>-way alignments. However judicious selection of a subset of all 3-way alignments can yield a further improvement with minimal additional effort. On the other hand, a simple heuristic to select a random subset of 3-way alignments (a random packing) yields accuracy comparable to averaging all 3-way alignments with substantially less computational effort.</p> <p>Conclusion</p> <p>Calculation of lower bounds on SP cost (and thus the quality of an alignment) can be improved by employing a mixture of 3-way and 2-way alignments.</p

Working Group Report: Heavy-Ion Physics and Quark-Gluon Plasma

This is the report of Heavy Ion Physics and Quark-Gluon Plasma at WHEPP-09 which was part of Working Group-4. Discussion and work on some aspects of Quark-Gluon Plasma believed to have created in heavy-ion collisions and in early universe are reported.Comment: 20 pages, 6 eps figures, Heavy-ion physics and QGP activity report in "IX Workshop on High Energy Physics Phenomenology (WHEPP-09)" held in Institute of Physics, Bhubaneswar, India, during January 3-14, 2006. To be published in PRAMANA - Journal of Physics (Indian Academy of Science

In vitro inhibitory activities of selected Australian medicinal plant extracts against protein glycation, angiotensin converting enzyme (ACE) and digestive enzymes linked to type II diabetes

This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.Background There is a need to develop potential new therapies for the management of diabetes and hypertension. Australian medicinal plants collected from the Kuuku I’yu (Northern Kaanju) homelands, Cape York Peninsula, Queensland, Australia were investigated to determine their therapeutic potential. Extracts were tested for inhibition of protein glycation and key enzymes relevant to the management of hyperglycaemia and hypertension. The inhibitory activities were further correlated with the antioxidant activities. Methods Extracts of five selected plant species were investigated: Petalostigma pubescens, Petalostigma banksii, Memecylon pauciflorum, Millettia pinnata and Grewia mesomischa. Enzyme inhibitory activity of the plant extracts was assessed against α-amylase, α-glucosidase and angiotensin converting enzyme (ACE). Antiglycation activity was determined using glucose-induced protein glycation models and formation of protein-bound fluorescent advanced glycation endproducts (AGEs). Antioxidant activity was determined by measuring the scavenging effect of plant extracts against 1, 1-diphenyl-2-picryl hydrazyl (DPPH) and using the ferric reducing anti-oxidant potential assay (FRAP). Total phenolic and flavonoid contents were also determined. Results Extracts of the leaves of Petalostigma banksii and P. pubescens showed the strongest inhibition of α-amylase with IC50 values of 166.50 ± 5.50 μg/mL and 160.20 ± 27.92 μg/mL, respectively. The P. pubescens leaf extract was also the strongest inhibitor of α-glucosidase with an IC50 of 167.83 ± 23.82 μg/mL. Testing for the antiglycation potential of the extracts, measured as inhibition of formation of protein-bound fluorescent AGEs, showed that P. banksii root and fruit extracts had IC50 values of 34.49 ± 4.31 μg/mL and 47.72 ± 1.65 μg/mL, respectively, which were significantly lower (p < 0.05) than other extracts. The inhibitory effect on α-amylase, α-glucosidase and the antiglycation potential of the extracts did not correlate with the total phenolic, total flavonoid, FRAP or DPPH. For ACE inhibition, IC50 values ranged between 266.27 ± 6.91 to 695.17 ± 15.38 μg/mL. Conclusions The tested Australian medicinal plant extracts inhibit glucose-induced fluorescent AGEs, α-amylase, α-glucosidase and ACE with extracts of Petalostigma species showing the most promising activity. These medicinal plants could potentially be further developed as therapeutic agents in the treatment of hyperglycaemia and hypertension