Ideal Platform (ideal + platform)

Distribution by Scientific Domains

Selected Abstracts

A Polymorphic Dynamic Network Loading Model

Nie Yu (Marco)
The polymorphism, realized through a general node-link interface and proper discretization, offers several prominent advantages. First of all, PDNL allows road facilities in the same network to be represented by different traffic flow models based on the tradeoff of efficiency and realism and/or the characteristics of the targeted problem. Second, new macroscopic link/node models can be easily plugged into the framework and compared against existing ones. Third, PDNL decouples links and nodes in network loading, and thus opens the door to parallel computing. Finally, PDNL keeps track of individual vehicular quanta of arbitrary size, which makes it possible to replicate analytical loading results as closely as desired. PDNL, thus, offers an ideal platform for studying both analytical dynamic traffic assignment problems of different kinds and macroscopic traffic simulation. [source]

Patterned Hydrogels for Controlled Platelet Adhesion from Whole Blood and Plasma

Tobias Ekblad
Abstract This work describes the preparation and properties of hydrogel surface chemistries enabling controlled and well-defined cell adhesion. The hydrogels may be prepared directly on plastic substrates, such as polystyrene slides or dishes, using a quick and experimentally simple photopolymerization process, compatible with photolithographic and microfluidic patterning methods. The intended application for these materials is as substrates for diagnostic cell adhesion assays, particularly for the analysis of human platelet function. The non-specific adsorption of fibrinogen, a platelet adhesion promoting protein, is shown to be completely inhibited by the hydrogel, provided that the film thickness is sufficient (>5,nm). This allows the hydrogel to be used as a matrix for presenting selected bioactive ligands without risking interference from non-specifically adsorbed platelet adhesion factors, even in undiluted whole blood and blood plasma. This concept is demonstrated by preparing patterns of proteins on hydrogel surfaces, resulting in highly controlled platelet adhesion. Further insights into the protein immobilization and platelet adhesion processes are provided by studies using imaging surface plasmon resonance. The hydrogel surfaces used in this work appear to provide an ideal platform for cell adhesion studies of platelets, and potentially also for other cell types. [source]

Self-Assembled Pb Nanostructures on Si(111) Surfaces: From Nanowires to Nanorings

Rui Wu
Abstract A template-directed growth method for metals is described in which ordered arrays of super-long single-crystalline metal nanowires with atomic-level-controlled width, thickness (height), and surface location are prepared by molecular beam epitaxy. Their subsequent examination by in situ scanning tunneling microscopy is also outlined. A phase-separated stripe pattern composed of alternately a Ge-rich incommensurate phase and a ,3,,,3 phase is first obtained by Ge deposition on Si(111) substrates. Further deposition of Pb on this patterned surface leads to a well-ordered array of super-long Pb nanowires. Using the same mechanism, superconducting Pb nanorings can also be fabricated. In this review of our recent work, these Pb single-crystalline nanowires and nanorings are shown to serve as an ideal platform for the study of superconductivity in reduced dimensionalities. Furthermore, because the widths and spatial distributions of two phases can be precisely controlled by the Ge coverage and substrate temperature, and because a metal will always selectively nucleate on one of two phases, this template-directed growth method can be applied to a wide range of metals. [source]

Charting protein complexes, signaling pathways, and networks in the immune system

Angela Bauch
Summary:, Systematic deciphering of protein,protein interactions has the potential to generate comprehensive and instructive signaling networks and to fuel new therapeutic and diagnostic strategies. Here, we describe how recent advances in high-throughput proteomic technologies, involving biochemical purification methods and mass spectrometry analysis, can be applied systematically to the characterization of protein complexes and the computation of molecular networks. The networks obtained form the basis for further functional analyses, such as knockdown by RNA interference, ultimately leading to the identification of nodes that represent candidate targets for pharmacological exploitation. No individual experimental approach can accurately elucidate all critical modulatory components and biological aspects of a signaling network. Such functionally annotated protein,protein interaction networks, however, represent an ideal platform for the integration of additional datasets. By providing links between molecules, they also provide links to all previous observations associated with these molecules, be they of genetic, pharmacological, or other origin. As exemplified here by the analysis of the tumor necrosis factor (TNF)-,/nuclear factor-,B (NF-,B) signaling pathway, the approach is applicable to any mammalian cellular signaling pathway in the immune system. [source]

In vitro Studies of Functionalized Mesoporous Silica Nanoparticles for Photodynamic Therapy

Hsiung-Lin Tu
A versatile platform for photodynamic therapy (PDT), mesoporous silica nanoparticles functionalized with protoporphyrin IX (PpIX-MSNs), has been developed. In vitro studies on HeLa cells show high uptake efficiency. Phototoxicity results give both irradiation time- and dosage-dependent cell death events. Because of the ease of incorporating other biomedical functional groups, we believe MSNs would be an ideal platform for biomedical applications. [source]

Analysis of nuclear proteome in C57 mouse liver tissue by a nano-flow 2-D-LC,ESI-MS/MS approach

Jie Zhang
Abstract The analysis of whole cell or tissue extracts is too complex for current protein identification technology and not suitable for the study of proteins with low copy levels. To concentrate and enrich low abundance proteins, organelle proteomics is a promising strategy. This approach can not only reduce the protein sample complexity but also provide information about protein location in cells, organs, or tissues under analysis. Nano-flow two-dimensional strong-cation exchange chromatography (SCX),RPLC,ESI-MS/MS is an ideal platform for analyzing organelle extracts because of its advantages of sample non-bias, low amounts of sample required, powerful separation capability, and high detection sensitivity. In this study, we apply nano-scale multidimensional protein identification technology to the analysis of C57 mouse liver nuclear proteins. Organelle isolation has been optimized to obtain highly pure nuclei. Evaluation of nucleus integrity and purity has been performed to demonstrate the effectiveness of the optimized isolation procedure. The extracted nuclear proteins were identified by five independent nano-flow on-line SCX,RPLC,ESI-MS/MS analyses to improve the proteome coverage. Finally, a total of 462 proteins were identified. Corresponding analyses of protein molecular mass and pI distribution and biological function categorization have been undertaken to further validate our identification strategy. [source]

Controlling the flow of light with silicon nanostructures

W. Park
Abstract Silicon is an important material for integrated photonics applications. High refractive index and transparency in the infrared region makes it an ideal platform to implement nanostructures for novel optical devices. We fabricated silicon photonic crystals and experimentally demonstrated negative refraction and self-collimation. We also used heterodyne near-field scanning optical microscope to directly visualize the anomalous wavefronts. When the periodicity is much smaller than wavelength, silicon photonic crystal can be described by the effective medium theory. By engineering effective refractive index with silicon nanorod size, we demonstrated an all-dielectric cloak structure which can hide objects in front of a highly reflecting plane. The work discussed in this review shows the powerful design flexibility and versatility of silicon nanostructures. ( 2010 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA) [source]

Artificial intelligence advancements applied in off-the-shelf controllers

Edward M. Marszal P.E.
Since the earliest process units were built, CPI engineers have employed artificial intelligence to prevent losses. The expanding use of computer-based systems for process control has allowed the amount of intelligence applied in these expert systems to drastically increase. Standard methods for performing Expert System tasks are being formalized by numerous researchers in industry and academia. Work products from these groups include designs that present process hazards knowledge in a structured, hierarchical, and modular manner. Advancements in programmable logic controller (PLC) technology have created systems with substantial computing power that are robust and fault tolerant enough to be used in safety critical applications. In addition, IEC 1131-3 standardized the programming languages available in virtually every new controller. The function block language defined in IEC 1131-3 is particularly well suited to performing modular tasks, which makes it an ideal platform for representing knowledge. This paper begins by describing some of the advancements in knowledge-based systems for loss prevention applications. It then explores how standard IEC 1131-3 programming techniques can be used to build function blocks that represent knowledge of the hazards posed by equipment items. The paper goes on to develop a sample function block that represents the hazards of a pressure vessel, using knowledge developed in the API 14-C standard. [source]

Foldon-guided self-assembly of ultra-stable protein fibers

Anshul Bhardwaj
Abstract A common objective in protein engineering is the enhancement of the thermodynamic properties of recombinant proteins for possible applications in nanobiotechnology. The performance of proteins can be improved by the rational design of chimeras that contain structural elements with the desired properties, thus resulting in a more effective exploitation of protein folds designed by nature. In this paper, we report the design and characterization of an ultra-stable self-refolding protein fiber, which rapidly reassembles in solution after denaturation induced by harsh chemical treatment or high temperature. This engineered protein fiber was constructed on the molecular framework of bacteriophage P22 tail needle gp26, by fusing its helical core to the foldon domain of phage T4 fibritin. Using protein engineering, we rationally permuted the foldon upstream and downstream from the gp26 helical core and characterized gp26-foldon chimeras by biophysical analysis. Our data demonstrate that one specific protein chimera containing the foldon immediately downstream from the gp26 helical core, gp26(1-140)-F, displays the highest thermodynamic and structural stability and refolds spontaneously in solution following denaturation. The gp26-foldon chimeric fiber remains stable in 6.0 M guanidine hydrochloride, or at 80C, rapidly refolds after denaturation, and has both N and C termini accessible for chemical/biological modification, thereby representing an ideal platform for the design of self-assembling nanoblocks. [source]

Automatic Extraction of ECG Strips from Continuous 12-lead Holter Recordings for QT Analysis at Prescheduled versus Optimized Time Points

Fabio Badilini Ph.D.
Background: Continuous 12-lead ECG monitoring (Holter) in early-phase pharmaceutical studies is today widely used as an ideal platform to extract discrete ECGs for analysis. The extraction process is typically performed manually by trained readers using commercial Holter processing systems. Methods: Antares, a novel method for automatic 12-lead extraction from continuous Holter recordings applying minimal noise criteria and heart-rate stability conditions is presented. A set of 12-lead Holter recordings from healthy subjects administered with sotalol is used to compare ECG extractions at fixed time points with ECG extractions generated by Antares optimizing noise and heart rate inside 5 minute windows centered around each expected time point of interest. Results: Global, low- and high-frequency noise content of extracted ECGs was significantly reduced via optimized approach by Antares. Heart rate was also slightly reduced (from 69 13 to 64 13 bpm, P < 0.05). Similarly, the corrected QT interval from optimized extractions was significantly reduced (QTcB from 414 32 to 402 30 ms, P < 0.05). Using only baseline data, and after adjusting for intersubject variability, the standard deviation (SD) of QT intervals was highly reduced with optimized extraction (SD of QTcF from 11 8 to 7 2 ms, P < 0.05). Conclusions: Extraction of discrete 12-lead ECG strips from continuous Holter generates less noisy and more stable ECGs leading to more robust QTc data, thereby potentially facilitating the assessment of ECG effects on clinical trials. [source]

Photocaged Agonist for an Analogue-Specific form of the Vitamin D Receptor

CHEMBIOCHEM, Issue 7 2007
John B. Biggins Dr.
Abstract Nuclear hormone receptors (NHRs) represent a diverse class of ligand-dependent transcriptional regulators. NHRs that have been rendered functionally inactive due to mutations that abrogate proper ligand binding can often be rescued by appropriately designed hormone analogues. The analogue-specific receptor,ligand pairs provide an ideal platform from which to develop new chemogenomic tools for the spatial and temporal control of gene expression. Here, we describe the synthesis and in vitro assessment of a photocaged VDR agonist specific to a mutant NHR that is associated with vitamin D-resistant rickets. The results provide insight into the utility of the agonist as a potential tool for photoinduced gene patterning. [source]