477 research outputs found
Analysis of the chemical diffusion master equation for creation and mutual annihilation reactions
We propose an infinite dimensional generating function method for finding the analytical solution of the so-called chemical diffusion master equation (CDME) for creation and mutual annihilation chemical reactions. CDMEs model by means of an infinite system of coupled Fokker-Planck equations the probabilistic evolution of chemical reaction kinetics associated with spatial diffusion of individual particles; here, we focus an creation and mutual annihilation chemical reactions combined with Brownian diffusion of the single particles. Using our method we are able to link certain finite dimensional projections of the solution of the CDME to the solution of a single linear fourth order partial differential equation containing as many variables as the dimension of the aforementioned projection space. Our technique extends the one presented in Lanconelli [J. Math. Anal. Appl. 526, 127352 (2023)] and Lanconelli et al. [arXiv:2302.10700 [math.PR] (2023)] which allowed for an explicit representation for the solution of birth-death type CDMEs
Trace elements in the kidney tissue of Bluefin Tuna (Thunnus thynnus L. 1758) in Turkish seas
Trace elements, namely lead (Pb), copper (Cu), manganese (Mn), nickel (Ni), zinc (Zn), and iron (Fe), found in kidney tissues were analyzed and compared between wild/fattened and female/male bluefin tuna (BFT) in the Eastern Mediterranean region of Turkey. One hundred (that is, 50 female and 50 male) individual specimens of wild and fattened tuna were investigated. The mean trace elements of the wild fish were determined to include Pb, 0.166; Cu, 1.683; Mn, 0.252; Ni, 0.322; Zn, 8.974; and Fe, 14.017 (ìg g-1 wt wt). The values for the fattened fish were determined to be Pb, 0.116; Cu, 1.279; Mn, 0.208; Ni, 0.231; Zn, 8.507; and Fe, 10.364 (ìg g-1 wt wt). The comparison of trace elements between wild and fattened fish was significant (p < 0.05). In terms of gender, the mean trace elements in the kidney tissue of wild and fattened female BFT were determined, respectively, to be Pb, 0.183, 0.124; Cu, 1.947, 1.250; Mn, 0.281, 0.217; Ni, 0.357, 0.229; Zn, 9.641, 9.205; and Fe, 14.351, 11.314. Similar values for wild and fattened male BFT were found, respectively, Pb, 0.149, 0.107; Cu, 1.418, 1.307; Mn, 0.223, 0.198; Ni, 0.286, 0.232; Zn, 8.307, 7.808; and Fe, 13.683, 9.413.Key words: Bluefin tuna, Thunnus thynnus, trace elements, lead, copper, manganese, nickel, zinc, iron,kidney
Major Mineral (P, K, Ca ) Contents and Proximate Compositions of the Male and Female Blue Swimming Crab (Portunus segnis Forskal, 1775) from Northeastern Mediterranean Sea, Mersin Bay, Turkey
The aim of this study was to demonstrate the nutritive value of blue swimming crab (Portunus segnis Forskal, 1775). Selected major mineral (P, K, Ca) contents, proximate compositions and fatty acids contents in female and male specimens of blue swimming were investigated. Crab samples used in this research were obtained from Northeastern Mediterranean Sea, Mersin Bay, Turkey. There were no significant differences in the nutritive value between the sexes (p>0.05). The protein was identified as 20.16% and 19.03% for female and male crab respevtively. This species was found to be rich in minerals and low in fat (0.66% for male, 0.91% for female) when compared with other economical crab species from Mediterranean Sea/Turkey. In fatty acid composition, the saturated fatty acid fraction was dominant, followed by monounsaturated fatty acid and polyunsaturated fatty acid for both sexes. In conclusion, from a nutritional point of view, both male and female blue swimming crab are demonstrated acceptable quality. Keywords: Minerals, Proximate analysis, Blue swimming crab; Portunus segnis; Mediterranean se
An improved crystal structure of C-phycoerythrin from the marine cyanobacterium Phormidium sp. A09DM
C-Phycoerythrin (PE) from Phormidium sp. A09DM has been crystallized using different conditions and its structure determined to atomic resolution (1.14 Å). In order for the pigment present, phycoerythrobilin (PEB), to function as an efficient light-harvesting molecule it must be held rigidly (Kupka and Scheer in Biochim Biophys Acta 1777:94–103, 2008) and, moreover, the different PEB molecules in PE must be arranged, relative to each other, so as to promote efficient energy transfer between them. This improved structure has allowed us to define in great detail the structure of the PEBs and their binding sites. These precise structural details will facilitate theoretical calculations of each PEB’s spectroscopic properties. It was possible, however, to suggest a model for which chromophores contribute to the different regions of absorption spectrum and propose a tentative scheme for energy transfer. We show that some subtle differences in one of these PEB binding sites in two of the 12 subunits are caused by crystal contacts between neighboring hexamers in the crystal lattice. This explains some of the differences seen in previous lower resolution structures determined at two different pH values (Kumar et al. in Photosyn Res 129:17–28, 2016)
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A Tubular Electrochemical Reactor for Slurry Electrodes
The research on electrochemical reactors is mostly limited to planarly designed modules. In this study, we compare a tubular and a planar electrochemical reactor for the utilization of the slurry electrodes. Cylindrical formed geometries demonstrate a higher surface-to-volume ratio, which may be favorable in terms of current density and volumetric power density. A tubular shaped electrochemical reactor is designed with conductive static mixers to promote the slurry particle mixing, and the vanadium redox flow battery is selected as a showcase application. The new tubular design presents similar cell resistances to the previously designed planar battery and shows increased discharge polarization behavior up to 100 mA cm−2. The volumetric power density reaches up to 30 mW cm−3, which is two times higher than that of the planar one. The battery performance is further investigated and 85 % coulombic, 70 % voltage and 60 % energy efficiency is found at 15 mA cm−2 with 15 wt.% slurry content. © 2020 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA
An integrated pipeline for building performance analysis:Daylighting, energy, natural ventilation, and airborne contaminant dispersion
Early design decisions influence the performance of a building significantly. Yet, computational support for performance assessment during early design is very limited. This research proposes an analysis pipeline for the accurate and comprehensive assessment of building performance by integrating simulation-based analysis tools that perform daylighting, computational fluid dynamics, energy, and contaminant transport simulations, as well as wind tunnel testing that performs velocity and pressure measurements to generate wind pressure coefficients. The pipeline is implemented in three different ways: hybrid, model-based, and empirical workflows. The hybrid workflow combines computational fluid dynamics simulations and wind tunnel testing, while the model-based and empirical workflows utilize computational fluid dynamics simulations and wind tunnel testing, respectively. In the pipeline, computational fluid dynamics is used early on to evaluate a high number of alternatives, leading to the selection of a limited number of good-performing options. Following this, wind tunnel testing is used to “correct” the initial wind pressure coefficient results for increased accuracy. Therefore, a hybrid approach operating with high accuracy that can effectively explore the design search space is needed. The pipeline is tested on a hypothetical office building with different shading device configurations. The coupling of computational and physical testing methods in a hybrid workflow significantly enhanced the accuracy of airflow-related data, which is underestimated by 15.4% using the model-based workflow. Moreover, the hybrid workflow managed the complexity of the design search space by the assessment and elimination of different design alternatives by the stepwise simulation workflow. The inclusion of shading devices also improved the accuracy of airflow-related data. If the shading devices had not been modeled for the simulations and had not been tested, the results would have overestimated the ventilation rate by 85% and underestimated the ventilation rate by 1.4%, respectively. The study's contribution is significant as it proposes a pipeline for a more accurate and comprehensive assessment of building performance, which can inform design decisions and improve the overall building's performance.</p
Metadata Provenance: Dublin Core on the Next Level
With this poster, we want to present the current state of the DCMI Metadata Provenance Task Group, which will wrap up its work at the time of DC-2011. The motivation for a Dublin Core extension for metadata provenance is twofold: Firstly, we want to represent existing metadata provenance information in a simple and unified way that is well suited as an application of Dublin Core. Secondly, we want to enable the provision of provenance information for Dublin Core metadata in a Dublin Core compatible way
Micromachined two-dimensional array piezoelectrically actuated transducers
Cataloged from PDF version of article.This letter presents micromachined two-dimensional array flextensional transducers that can be used to generate sound in air or water. Individual array elements consist of a thin piezoelectric ring and a thin, fully supported, circular membrane. We report on an optimum design for an individual array element based on finite element modeling. We manufacture the transducer in two-dimensional arrays using planar silicon micromachining and demonstrate ultrasound transmission in air at 2.85 MHz. Such an array could be combined with on-board driving and an addressing circuitry for different applications.
© 1998 American Institute of Physic
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Titanium-Based Static Mixer Electrodes to Improve the Current Density of Slurry Electrodes
Complex geometries for electrodes are a great challenge in electrochemical applications. Slurry electrodes have been one example, which use complex flow distributors to improve the charge transfer between the current collector and the slurry particles. Here we use titanium-based flow distributors produced by indirect 3D-printing to improve further the electron transfer from highly conductive flow distributors to the slurry particles for a vanadium redox flow application. The titanium static mixers are directly coated with graphite to increase the activity for vanadium redox reactions. Increasing layers of graphite have shown an optimum for the positive and negative electrolytes. The application of heat treatment on the electrodes improves the anodic and cathodic current peaks drastically. Testing the highly conductive static mixers in a self-made redox flow cell results in 110 mA cm−2 discharge polarization
The Effect of Antioxidants on Ischemia-Reperfusion Injury in Flap Surgery
Flap surgery has wide use in plastic surgery in the closure of tissue defects. In spite of the major advances in plastic surgery in the past years, flap surgery is still associated with significant mortality. Ischemia-reperfusion (I/R) injury, which is a complex injury associated with flap blood flow, is one of the most important causes of flap failure. The main pathophysiology underneath I/R injury is associated with reactive oxygen species, which can be prevented by certain antioxidant applications. Antioxidants have been widely used in flap surgery and I/R injury previously. There have been a lot of articles showing positive effects of antioxidants on I/R injury. In this chapter, we focus the mechanism of I/R injury and how antioxidants can able to diminish the damage, moreover demonstrating the effect of certain antioxidants on I/R injury that has been investigated previously
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