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排序方式: 共有532条查询结果,搜索用时 31 毫秒
81.
Chakravarthy VS Gupte N Yogesh S Salhotra A 《International journal of neural systems》2008,18(2):157-164
Synchronization of chaotic low-dimensional systems has been a topic of much recent research. Such systems have found applications for secure communications. In this work we show how synchronization can be achieved in a high-dimensional chaotic neural network. The network used in our studies is an extension of the Hopfield Network, known as the Complex Hopfield Network (CHN). The CHN, also an associative memory, has both fixed point and limit cycle or oscillatory behavior. In the oscillatory mode, the network wanders chaotically from one stored pattern to another. We show how a pair of identical high-dimensional CHNs can be synchronized by communicating only a subset of state vector components. The synchronizability of such a system is characterized through simulations. 相似文献
82.
The mechanisms that mediate biomembrane shape transformations are of considerable interest in cell biology. Recent in vitro experiments show that the chemical transformation of minor membrane lipids can induce dramatic shape changes in biomembranes. Specifically, it was observed that the addition of DOPA to DOPE has no effect on the stability of the bilayer structure of the membrane. In contrast, the addition of LPA to DOPE stabilizes the bilayer phase of DOPE, increasing the temperature of a phase transition from the bilayer to the inverted hexagonal phase. This result suggests that the chemical conversion of DOPA to LPA is sufficient for triggering a dramatic change in the shape of biomembranes. The LPA/DOPA/DOPE mixture of lipids provides a simple model system for understanding the molecular events driving the shape change. In this work, we used coarse-grained molecular dynamics simulations to study the phase transitions of this lipid mixture. We show that despite the simplicity of the coarse-grained model, it reproduces the experimentally observed phase changes of: 1), pure LPA and DOPA with respect to changes in the concentration of cations; and 2), LPA/DOPE and DOPA/DOPE mixtures with respect to temperature. The good agreement between the model and experiments suggests that the computationally inexpensive coarse-grained approach can be used to infer macroscopic membrane properties. Furthermore, analysis of the shape of the lipid molecules demonstrates that the phase behavior of single-lipid systems is consistent with molecular packing theory. However, the phase stability of mixed lipid systems exhibits significant deviations from this theory, which suggests that the elastic energy of the lipids, neglected in the packing theory, plays an important role. 相似文献
83.
Achur RN Kakizaki I Goel S Kojima K Madhunapantula SV Goyal A Ohta M Kumar S Takagaki K Gowda DC 《Biochemistry》2008,47(47):12635-12643
Infection with Plasmodium falciparum during pregnancy results in the adherence of infected red blood cells (IRBCs) in placenta, causing pregnancy-associated malaria with severe health complications in mothers and fetuses. The chondroitin 4-sulfate (C4S) chains of very low sulfated chondroitin sulfate proteoglycans (CSPGs) in placenta mediate the IRBC adherence. While it is known that partially sulfated but not fully sulfated C4S effectively binds IRBCs, structural interactions involved remain unclear and are incompletely understood. In this study, structurally defined C4S oligosaccharides of varying sulfate contents and sizes were evaluated for their ability to inhibit the binding of IRBCs from different P. falciparum strains to CSPG purified from placenta. The results clearly show that, with all parasite strains studied, dodecasaccharide is the minimal chain length required for the efficient adherence of IRBCs to CSPG and two 4-sulfated disaccharides within this minimal structural motif are sufficient for maximal binding. Together, these data demonstrate for the first time that the C4S structural requirement for IRBC adherence is parasite strain-independent. We also show that the carboxyl group on nonreducing end glucuronic acid in dodecasaccharide motif is important for IRBC binding. Thus, in oligosaccharides containing terminal 4,5-unsaturated glucuronic acid, the nonreducing end disaccharide moiety does not interact with IRBCs due to the altered spatial orientation of carboxyl group. In such C4S oligosaccharides, 14-mer but not 12-mer constitutes the minimal motif for inhibition of IRBC binding to placental CSPG. These data have important implications for the development and evaluation of therapeutics and vaccine for placental malaria. 相似文献
84.
85.
Rong Chen Alex A Morgan Joel Dudley Tarangini Deshpande Li Li Keiichi Kodama Annie P Chiang Atul J Butte 《Genome biology》2009,9(12):R170
Background
Candidate single nucleotide polymorphisms (SNPs) from genome-wide association studies (GWASs) were often selected for validation based on their functional annotation, which was inadequate and biased. We propose to use the more than 200,000 microarray studies in the Gene Expression Omnibus to systematically prioritize candidate SNPs from GWASs. 相似文献86.
Ultrasonic storage modulus as a novel parameter for analyzing protein-protein interactions in high protein concentration solutions: correlation with static and dynamic light scattering measurements 下载免费PDF全文
The purpose of this work was to establish ultrasonic storage modulus (G') as a novel parameter for characterizing protein-protein interactions (PPI) in high concentration protein solutions. Using an indigenously developed ultrasonic shear rheometer, G' for 20-120 mg/ml solutions of a monoclonal antibody (IgG(2)), between pH 3.0 and 9.0 at 4 mM ionic strength, was measured at frequency of 10 MHz. Our understanding of ultrasonic rheology indicated decrease in repulsive and increase in attractive PPI with increasing solution pH. To confirm this behavior, dynamic (DLS) and static (SLS) light scattering measurements were conducted in dilute solutions. Due to technical limitations, light scattering measurements could not be conducted in concentrated solutions. Mutual-diffusion coefficient, measured by DLS, increased with IgG(2) concentration at pH 4.0 and this trend reversed as pH was increased to 9.0. Second virial coefficient, measured by SLS, decreased with increasing pH. These observations were consistent with the nature of PPI understood from G' measurements. Ultrasonic rheology, DLS, and SLS measurements were also conducted under conditions of increased ionic strength. The consistency between rheology and light scattering analysis under various solution conditions established the utility of ultrasonic G' measurements as a novel tool for analyzing PPI in high protein concentration systems. 相似文献
87.
Shouvik Kumar Nandy Sattwik Das Sadanand Pandey Pallab Kalita Manoj K. Gupta Atul Kabra Pankaj Wadhwa Deepak Kumar 《Luminescence》2024,39(5):e4771
The second-most common cause of death resulting from genetic mutations in DNA sequences is cancer. The difficulty in the field of anticancer research is the application of the traditional methods, which also affects normal cells. Mutations, genetic replication alterations, and chromosomal abnormalities have a direct impact on the effectiveness of anticancer drugs at different stages. Presently, therapeutic techniques utilize nanotechnology, transition metal dichalcogenides (TMDCs), and robotics. TMDCs are being increasingly employed in tumor therapy and biosensing applications due to their biocompatibility, adjustable bandgap, versatile functionality, exceptional photoelectric properties, and wide range of applications. This study reports the advancement of nanoplatforms based on TMDCs that are specifically engineered for responsive and intelligent cancer therapy. This article offers a thorough examination of the current challenges, future possibilities for theranostic applications using TMDCs, and recent progress in employing TMDCs for cancer therapy. Currently, there is significant interest in two-dimensional (2D) TMDCs nanomaterials as ultrathin unique physicochemical properties. These materials have attracted attention in various fields, including biomedicine. Due to their inherent ability to absorb near-infrared light and their exceptionally large surface area, significant efforts are being made to prepare multifunctional nanoplatforms based on 2D TMDCs. 相似文献
88.
Saurabh Dixit Dieudonné R. Baganizi Rajnish Sahu Ejowke Dosunmu Atul Chaudhari Komal Vig Shreekumar R. Pillai Shree R. Singh Vida A. Dennis 《Journal of biological engineering》2017,11(1):49
The repair or replacement of damaged skins is still an important, challenging public health problem. Immune acceptance and long-term survival of skin grafts represent the major problem to overcome in grafting given that in most situations autografts cannot be used. The emergence of artificial skin substitutes provides alternative treatment with the capacity to reduce the dependency on the increasing demand of cadaver skin grafts. Over the years, considerable research efforts have focused on strategies for skin repair or permanent skin graft transplantations. Available skin substitutes include pre- or post-transplantation treatments of donor cells, stem cell-based therapies, and skin equivalents composed of bio-engineered acellular or cellular skin substitutes. However, skin substitutes are still prone to immunological rejection, and as such, there is currently no skin substitute available to overcome this phenomenon. This review focuses on the mechanisms of skin rejection and tolerance induction and outlines in detail current available strategies and alternatives that may allow achieving full-thickness skin replacement and repair. 相似文献
89.
Singh P Mittal A Bhardwaj A Kaur S Kumar S 《Bioorganic & medicinal chemistry letters》2008,18(1):85-89
Indoles carrying a cyclic ester (gamma-butyrolactone) at C-3 position have been synthesized by the allylation of 3-indoleglyoxylate followed by iodocyclisation and the nucleophilic replacement of the iodo-group. Screening of these molecules for COX-2 inhibition and anti-cancer activities has identified compounds 10 and 11 as highly potent and selective for COX-2 as well as showing remarkable anti-cancer activities (better than that of indomethacin). 相似文献
90.
Resende R Moreira PI Proença T Deshpande A Busciglio J Pereira C Oliveira CR 《Free radical biology & medicine》2008,44(12):2051-2057
Alzheimer disease (AD) is a neurodegenerative disease which is characterized by the presence of extracellular senile plaques mainly composed of amyloid-beta peptide (Abeta), intracellular neurofibrillary tangles, and selective synaptic and neuronal loss. AD brains revealed elevated levels of oxidative stress markers which have been implicated in Abeta-induced toxicity. In the present work we addressed the hypothesis that oxidative stress occurs early in the development of AD and evaluated the extension of the oxidative stress and the levels of antioxidants in an in vivo model of AD, the triple-transgenic mouse, which develops plaques, tangles, and cognitive impairments and thus mimics AD progression in humans. We have shown that in this model, levels of antioxidants, namely, reduced glutathione and vitamin E, are decreased and the extent of lipid peroxidation is increased. We have also observed increased activity of the antioxidant enzymes glutathione peroxidase and superoxide dismutase. These alterations are evident during the Abeta oligomerization period, before the appearance of Abeta plaques and neurofibrillary tangles, supporting the view that oxidative stress occurs early in the development of the disease. 相似文献