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21.
Iron-sulfur clusters are multifaceted iron-containing cofactors coordinated and utilized by numerous proteins in nearly all biological systems. Fe-S-cluster-containing proteins help direct pathways essential for cell viability and participate in biological applications ranging from nucleotide biosynthesis and stability, protein translation, enzyme catalysis, and mitochondrial metabolism. Fe-S-containing proteins function by utilizing the unique electronic and chemical properties inherent in the Fe containing cofactor. Fe-S clusters are constructed of inorganic iron and sulfide arranged in a distinct caged structural makeup ranging from [Fe(2) -S(2) ], [Fe(3) -S(4) ], [Fe(4) -S(4) ], up to [Fe(8) -S(8) ] clusters. In eukaryotes, cluster activity is controlled in part at the assembly level and the major pathway for cluster production exists within the mitochondria. Recent insight into the pathway of mitochondrial cluster assembly has come from new in vivo and in vitro reports that provided direct insight into how all protein partners within the assembly pathway interact. However, we are only just beginning to understand the role of each protein within this complex pageant that is mitochondrial Fe-S cluster assembly. In this report we present results, using the yeast model for mitochondrial assembly, to describe the molecular details of how important proteins in the pathway coordinate for cluster assembly. 相似文献
22.
Nano-structured nickel oxide based DNA biosensor for detection of visceral leishmaniasis (Kala-azar)
Sol-gel synthesized nickel oxide (NiO) film deposited onto indium tin oxide (ITO) coated glass plate has been utilized for the development of sensitive and stable DNA biosensor and demonstrated for diagnosis of visceral leishmaniasis also known as Kala-azar. Leishmania specific sensor is developed by immobilizing 23mer DNA sequence (oligonucleotide) identified from 18S rRNA gene sequences from Leishmania donovani. Characterization studies like X-Ray Diffraction and Scanning Electron Microscopy revealed the formation of nano-structured NiO, while immobilization of single strand (ss)-DNA of Leishmania was supported by UV-visible, Fourier Transform Infrared Spectroscopy and Scanning Electron Microscopy techniques. Response studies of ss-DNA/NiO/ITO bioelectrode are carried out using differential pulsed voltammetry in presence of methylene blue redox dye as a redox mediator. A linear response is obtained in the wide concentration range of 2 pg ml(-1) to 2 μg ml(-1) of complementary target genomic DNA (disease DNA) within the variation of 10% for 5 sets of studies. The observed results hold promise not only for diagnosis of Kala-azar patients but also hold enormous potential of the nano-NiO based probe for development of stable and sensitive biosensors. 相似文献
23.
A molecular dynamics study of the interaction of oleate and dodecylammonium chloride surfactants with complex aluminosilicate minerals 总被引:1,自引:0,他引:1
Rai B Sathish P Tanwar J Pradip Moon KS Fuerstenau DW 《Journal of colloid and interface science》2011,362(2):510-516
Surface characteristics of complex aluminosilicate minerals like spodumene [LiAl(SiO(3))(2)], jadeite [NaAl(SiO(3))(2)], feldspar [KAlSi(3)O(8)], and muscovite [K(2)Al(4)(Al(2)Si(6)O(20))(OH)(4)]) are modeled. Surface energies are computed for the cleavage planes of these minerals. Adsorption mechanisms of anionic chemisorbing type oleate and cationic physisorbing type dodecylammonium chloride molecules on two different crystal planes, that is (110) and (001), of spodumene and jadeite are studied in terms of the surface-surfactant interaction energies computed using molecular dynamics (MD) simulations. The conclusions drawn from purely theoretical computations match remarkably well with our experimental results. 相似文献
24.
The positions of maxima and minima in the rainbow structure have been calculated for the Kihara core potential by using the uniform approximation. The results have been reported in the tabular form as functions of reduced energy, quantum parameter and core diameter. The potential parameters for this potential have been determined for the systems Ar-Kr and Ar-Xe from the rainbow data in conjunction with other properties. The results show the success of the Kihara potential in interpreting the various properties of the systems considered by using a single set of potential parameters. 相似文献
25.
A higher order uniformly convergent method for singularly perturbed parabolic turning point problems
Swati Yadav Pratima Rai Kapil K. Sharma 《Numerical Methods for Partial Differential Equations》2020,36(2):342-368
In this article, we study numerical approximation for a class of singularly perturbed parabolic (SPP) convection-diffusion turning point problems. The considered SPP problem exhibits a parabolic boundary layer in the neighborhood of one of the sides of the domain. Some a priori bounds are given on the exact solution and its derivatives, which are necessary for the error analysis. A numerical scheme comprising of implicit finite difference method for time discretization on a uniform mesh and a hybrid scheme for spatial discretization on a generalized Shishkin mesh is proposed. Then Richardson extrapolation method is applied to increase the order of convergence in time direction. The resulting scheme has second-order convergence up to a logarithmic factor in space and second-order convergence in time. Numerical experiments are conducted to demonstrate the theoretical results and the comparative study is done with the existing schemes in literature to show better accuracy of the proposed schemes. 相似文献
26.
Swati Mukhopadhyay 《中国物理 B》2013,(7):298-302
A boundary layer analysis is presented for non-Newtonian fluid flow and heat transfer over a nonlinearly stretching surface. The Casson fluid model is used to characterize the non-Newtonian fluid behavior. By using suitable transformations, the governing partial differential equations corresponding to the momentum and energy equations are converted into non-linear ordinary differential equations. Numerical solutions of these equations are obtained with the shooting method. The effect of increasing Casson parameter is to suppress the velocity field. However the temperature is enhanced with the increasing Casson parameter. 相似文献
27.
Dr. Swati Deswal Rishukumar Panday Dr. Dipti R. Naphade Prashant Dixit Dr. Balu Praveenkumar Dr. Jan K. Zaręba Prof. Dr. Thomas D. Anthopoulos Prof. Dr. Satishchandra Ogale Prof. Dr. Ramamoorthy Boomishankar 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(33):e202200751
Bismuth containing hybrid molecular ferroelectrics are receiving tremendous attention in recent years owing to their stable and non-toxic composition. However, these perovskite-like structures are primarily limited to ammonium cations. Herein, we report a new phosphonium based discrete perovskite-like hybrid ferroelectric with a formula [Me(Ph)3P]3[Bi2Br9] ( MTPBB ) and its mechanical energy harvesting capability. The Polarization-Electric field (P-E) measurements resulted in a well-defined ferroelectric hysteresis loop with a remnant polarization value of 2.1 μC cm−2. Piezoresponse force microscopy experiments enabled visualization of the ferroelectric domain structure and evaluation of the piezoelectric strain coefficient (d33) for an MTPBB single crystal and thin film sample. Furthermore, flexible devices incorporating MTPBB in polydimethylsiloxane (PDMS) matrix at various concentrations were fabricated and explored for their mechanical energy harvesting properties. The champion device with 20 wt % of MTPBB in PDMS rendered a maximum peak-to-peak open-circuit voltage of 22.9 V and a maximum power density of 7 μW cm−2 at an optimal load of 4 MΩ. Moreover, the potential of MTPBB -based devices in low power electronics was demonstrated by storing the harvested energy in various electrolytic capacitors. 相似文献
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Chitinases are glycosyl hydrolases that catalyze the hydrolysis of β-(1,4)-glycosidic bonds in chitin, the major structural polysaccharide presented in the cuticle and gut peritrophic matrix of insects. Two aspartate residues (D143, D145) and one tryptophan (W146) in the Lymantria dispar chitinase are highly conserved residues observed within the second conserved motif of the family 18 chitinase catalytic region. In this study, a chitinase cDNA, LdCht5, was cloned from L. dispar, and the roles of the three residues were investigated using site-directed mutagenesis and substituting them with three other amino acids. Seven mutant proteins, D143E, D145E, W146G, D143E/D145E, D143E/W146G, D145E/W146G, and D143E/D145E/W146G, as well as the wild-type enzyme, were produced using the baculovirus-insect cell line expression system. The enzymatic and kinetic properties of these mutant enzymes were measured using the oligosaccharide substrate MU-(GlcNAc)3. Among the seven mutants, the D145E, D143E/D145E, and D145E/W146G mutations kept some extant catalytic activity toward MU-(GlcNAc)3, while the D143E, W146G, D143E/W146G, and D143E/D145E/W146G mutant enzymes were inactivated. Compared with the mutant enzymes, the wild-type enzyme had higher values of k cat and k cat / K m . A study of the multiple point mutations in the second conserved catalytic region would help to elucidate the role of the critical residues and their relationships. 相似文献