bluuebunny/crossref_metadata_2025_split huggingface dataset:
Brain Function, Magnetic Resonance Imaging of
Authors: Uğurbil Kâmil , Chen Wei , Harel Noam , Van de Moortele Pierre-Francois , Yacoub Essa , Zhu Xiaohan , Uludaǧ Kamil 
Published: April 2006

AbstractMost of our understanding of brain function derives from electrophysiology studies that use single and multiple unit recordings. This methodology is precise, but tedious, and the data produced are inherently undersampled because coverage over large areas of the cortex is impractical. Optical imaging techniques provide an alternative approach. However, these methods cannot penetrate more than ∼1 mm in depth on the exposed cortical surface when used for high‐resolution functional mapping and are restricted to a few millimeters with relatively course spatial resolution when performed non‐invasively through the intact scalp and skull. Radioactively labeled glucose analog 2‐[1‐14C]‐deoxyglucose has been used in early seminal experiments on functional parcellation in the brain; this method, however, is limited by the availability of differently labeled glucose analogs, and hence, the number of conditions that can be studied in a single animal. Of course, a major drawback with all of these methodologies is that they are invasive, or even terminal, therefore, unsuitable for human brain applications.These limitations are the reasons why functional magnetic resonance imaging (fMRI), since its introduction, has come to play a dominant role in both human and animal model studies.
Photoconducting Devices
Authors: Bhatia Vasuda , Narayan K.S. 
Published: April 2006

Abstract
Devices that change their resistance upon exposure to incident radiation are called photoconducting devices. A photoconducting device or a photoconductor can also be termed a photoresistor, photoconductive cell, or a photocell. Photoconductivity was first observed in selenium more than 100 years ago. In general, electrical conductivity of materials, especially semiconductors, increases with the photoexcitation. These devices have simple structure, low cost of fabrication, and rugged features and thus have numerous applications. Applications include detectors (flame, smoke, or burglar), photographic meters, electrophotography, card readers, lighting controls for street lamps, detection of nuclear radiation, electrical switches controlled by light, variable resistance in a circuit, and so on. Extrinsic photoconductors can also operate in long wavelength regions and thus make popular infrared photodetectors.
Photovoltaic Cells
Authors: Richards Bryce S. , Green Martin A. 
Published: April 2006

AbstractPhotovoltaic cells use the photovoltaic effect to convert sunlight directly into electric current and voltage. The efficiency of the conversion process ranges from a few percent up to nearly 37%, depending on the type of photovoltaic cell. In addition, they are sold with warranties of up to 30 years and generate many times their embodied energy during their operation lifetime. The energy conversion is performed silently, without moving parts or the emission of greenhouse gases, they require little or no maintenance and are modular. The first application of photovoltaic cells, also commonly called solar cells, was for powering spacecraft, but they have been used for many years to power a wide range of products, such as watches, calculators, navigation aids, telecommunications equipment, and also to provide power in remote locations via solar‐home systems. The most important present market is grid‐connected photovoltaic (PV) arrays, which can also serve as a structural part of a roof or façade, circumventing the issue of energy storage. Photovoltaic cells have also been applied in biomedical engineering, in areas such as imaging, powering implanted devices, and acting as a sensor.
Plasma Separation and Purification by Membrane
Authors: Jaffrin Michel Y. , Legallais Cecile 
Published: April 2006

Abstract
This article presents the various applications of plasma separation (plasmapheresis) from whole blood, consisting mainly of plasma and platelet collections from donors and therapeutic plasma purification with emphasis on membrane processes. It also describes the various available techniques for these applications. Plasma collection from donors is mainly achieved by continuous centrifugation because of its low cost, with a centrifugal bowl placed in an extracorporeal circuit or with a small cylindrical rotating filter the Autopheresis C from Baxter. Therapeutic plasma purification can be carried out by first separating plasma from blood by membrane filtration and replacing it by an albumin solution of fresh frozen plasma obtained from donors. Other described techniques consist of selective removal of a pathogeneous molecule by secondary filtration, chemical adsorption, or immunoadsorption. Respective advantages and drawbacks of these methods are discussed. The last section describes a method of blood salvage during surgery by washing and concentration of red blood cells by a plasmapheresis membrane.
Prosthetic Devices and Methods
Authors: Gard Steven 
Published: April 2006

AbstractLimb prostheses are designed to replace missing or absent anatomical limbs for the purpose of providing increased function or cosmesis. The goal of the prosthetist is to fit the patient with a prosthesis that best suits their needs and is able to maximize their rehabilitation potential while minimizing disability. Some of the issues that the prosthetist must consider when fabricating a prosthesis include the patient's level of amputation, the condition of their residual anatomy, and the potential impact other health problems may have on their prosthetic usage. Furthermore, the patient's age, gender, activity level, rehabilitation goals, vocational needs, and avocational desires must also be taken into account. The goal in the fitting of lower‐limb prostheses is generally to restore a person's ability to stand and ambulate, and the components are selected by the prosthetist according to the potential walking ability of the patient. Upper‐limb prostheses are used for reaching, grasping, holding, and positioning objects. Issues concerning the control and interfacing of the upper‐limb prosthesis with the body are of primary consideration. The latest technological advances in prosthetic limb components have been aimed at improving function and simplifying operation, with the goal of enabling users to move naturally and to effectively interact with the environment.
Radon Transform
Authors: Dhawan Atam 
Published: April 2006

Abstract
The mathematical foundation of multi‐dimensional imaging with image reconstruction algorithms was laid out by Radon in his classic paper on image reconstruction from projections that was published in 1917. However, the implementation of the Radon transform for reconstructing medical images from the data collected from imaging instrumentation was only realized in the 1960s. In 1963, A. M. Cormack showed radiological applications of the representation of a function through line integrals and later developed a model for image reconstruction from projections using Radon's work. In 1972, G. N. Hounsfield developed the first commercial x‐ray computed tomography (CT) scanner that used a computerized image reconstruction algorithm based on the Radon transform. G. N. Hounsfield and A. M. Cormack jointly received the 1979 Nobel Prize for their contributions to the development of computerized tomography for radiological applications. Radon transform has found a large number of application areas including medical imaging, microscopy, astronomy, and geophysics.
It should be noted that although the early evolution in computed tomography was based on image reconstruction using parallel‐beam geometry‐based image scanners, more sophisticated geometrical configuration and scanning instrumentation are used today for faster data collection and image reconstruction. New computed tomography (CT) image scanners (often called fourth‐generation CT scanners) use a cone‐beam of x‐ray radiation and multiple rings of detectors for fast 3‐D multislice scanning. Also, the basic Radon transform that established the foundation of image reconstruction from projections has been extended to a spectrum of exciting applications of image reconstructions in multi‐dimensional space using a variety of imaging modalities. However, the discussion in this chapter is focused on 2‐D representation of Radon transform only for image reconstruction from projections that are obtained through parallel‐beam scanning geometry in computed tomography.
Transport Across Endothelial Barriers, Modeling of
Authors: Fu Bingmei 
Published: April 2006

AbstractMicrovessel walls consist mainly of endothelial cells. Vascular endothelium is the principle barrier to, and regulator of, material exchange between circulating blood and the body tissues. The ultrastructural pathways and mechanisms whereby endothelial cells and the cleft between the cells modulate microvessel permeability to water and solutes have been a classic question in microvessel transport since the early 1950s. To bridge the gap between the ultrastructural data from serial section electron microscopy study about the cleft between endothelial cells (structure) andin vivomeasurement of microvessel permeability to water and solutes (function), a series of mathematical models have been developed since the 1950s. These models show that permeabilities to water and hydrophilic (water‐loving) solutes in microvessels of different tissues can be accounted for by interendothelial cleft pathways with a surface fiber layer and junction strands with discontinuous leakages. The surface glycocalyx (fiber matrix) layer at the luminal entrance of the cleft serves as a molecular filter and is crucial for microvessel walls to maintain low permeability to macromolecules.
Pharmacokinetic and Pharmacodynamic Control
Authors: Park Kyungsoo , D'Argenio David Z. 
Published: April 2006

Abstract

The use of mathematical modeling and simulation is central to the study of the absorption, distribution, and elimination of therapeutic drugs (pharmacokinetics) and to understanding how drugs produce their effects (pharmacodynamics). From its inception, the field of pharmacokinetics and pharmacodynamics has applied methods of mathematical modeling, estimation, simulation, experiment design, and control in an effort to better understand, quantify, and regulate the processes of uptake, disposition, and action of therapeutic drugs. These methods for pharmacokinetic/pharmacodynamic systems analysis impact all aspects of drug development including
in vitro
, animal and human testing, as well as drug therapy. Systems analysis methods applied to pharmacokinetic/pharmacodynamic processes confront many challenges related in part to the severe restrictions on the number and type of measurements that are available from laboratory experiments and clinical trials, as well as the variability in the experiments and the uncertainty associated with the processes themselves. Accordingly, specialized pharmacokinetic/pharmacodynamic systems analysis methods have been developed that address these unique challenges. This chapter focuses on the control of pharmacokinetic/pharmacodynamic processes, which has application to the problems of dose regimen design for patient therapy (pharmacotherapeutics) and for the design of clinical drug trials. After a review of the field, a general pharmacokinetic/pharmacodynamic modeling framework is presented and the control problem is presented, followed by a discussion of the enabling computational methods along with an example illustrating the problem and methods.
Transcutaneous Magnetic Coupling of Power and Data
Authors: Ghovanloo Maysam , Lazzi Gianluca 
Published: April 2006

AbstractSince the invention of the first implantable pacemaker in 1958, wireless implantable microelectronic devices (IMDs) have been significantly improved by going through many generations. They have made it possible to treat a wide range of ailments and disabilities from bradycardia and chronic back pain to epilepsy and deafness. IMDs have the potential to alleviate more challenging types of disabilities such as blindness and paralysis. These devices need to transmit and receive information wirelessly across the skin barrier as breaching the skin with interconnect wires would be a source of morbidity for the patient and significantly increases the risk of infection.IMDs can be divided inautonomousandsensorydevices which, in turn, results in different requirements for the wireless telemetry system. Autonomous devices such as pacemakers, cardioverters, and deep‐brain stimulators usually have a small number of stimulating sites (<5), low stimulus pulse rates (<500/s), and low power requirements. The anatomical location of implantation for most autonomous devices in the body allows them to be large enough to contain an energy source that would last for several years. Their autonomous operation limits the need to communicate with the external world to only occasional adjustments and interrogations, which can take place at low data rates. On the other hand, in sensory prosthetic devices—those that interface with the central nervous system (CNS) to restore a sensory function such as hearing or vision—the quality of perception enhances with the number of stimulating sites/electrodes and the rate of stimulation. These latter devices may stimulate the neural tissue by means of tens to hundreds of stimulating channels and, consequently, they generally require considerably more power and communication bandwidth than autonomous devices. Future visual prostheses might even go beyond one thousand sites to better provide the most important visual functions to the blind such as mobility without a cane, face recognition, and reading. Thus, sensory prosthetic devices usually require an inductive link between two (or more) magnetically couple coils for the transmission of power and data to the implanted device.
Electrical Activity in Cardiac Tissue, Modeling of
Authors: Cloherty S.L. , Dokos S. , Lovell N.H. 
Published: April 2006

Abstract
The heart is a complex organ, exhibiting significant variation in both structural and functional characteristics from one region to another. Mathematical modeling represents a powerful tool for improving our understanding of the mechanisms underlying both normal and abnormal cardiac function. This article describes the techniques routinely employed in modeling the electrical activity of the heart at the cellular and tissue scales. These techniques have proven useful in modeling the structural and functional characteristics in all areas of the heart and provide a foundation for constructing integrated models of the entire heart.
Interface Modification to Improve Hole‐Injection Properties in Organic Electronic Devices
Authors: Choulis S. A. , Choong V.‐E. , Patwardhan A. , Mathai M. K. , So F. 
Published: April 2006

AbstractThe performance of organic electronic devices is often limited by injection. In this paper, improvement of hole injection in organic electronic devices by conditioning of the interface between the hole‐conducting layer (buffer layer) and the active organic semiconductor layer is demonstrated. The conditioning is performed by spin‐coating poly(9,9‐dioctyl‐fluorene‐co‐N‐ (4‐butylphenyl)‐diphenylamine) (TFB) on top of the poly(3,4‐ethylene dioxythiophene): poly(styrene sulfonate) (PEDOT:PSS) buffer layer, followed by an organic solvent wash, which results in a TFB residue on the surface of the PEDOT:PSS. Changes in the hole‐injection energy barriers, bulk charge‐transport properties, and current–voltage characteristics observed in a representative PFO‐based (PFO: poly(9,9‐dioctylfluorene)) diode suggest that conditioning of PEDOT:PSS surface with TFB creates a stepped electronic profile that dramatically improves the hole‐injection properties of organic electronic devices.
Engineering Increased Stability into Self‐Assembled Protein Fibers
Authors: Smith A. M. , Banwell E. F. , Edwards W. R. , Pandya M. J. , Woolfson D. N. 
Published: April 2006

AbstractTwo stages in the rational redesign of a peptide‐based, self‐assembling fiber (SAF) are described. The SAF system comprises two peptides designed to form an offset α‐helical coiled‐coil heterodimer. The “sticky‐ends” are complementary and promote longitudinal assembly. Alone, the two peptides are unstructured, but co‐assemble upon mixing to form α‐helical fibrils, which bundle to form fibers 40–50 nm wide and tens of micrometers long. Assembly is controllable and occurs at pH 7 in water, making SAFs a potential scaffold for 3D cell culture. The purposes of the redesigns were 1) to investigate the fiber‐thickening process, and 2) to increase fiber stability for potential biological and biomedical applications. First, mutations were made to the original peptide designs to increase fibril–fibril interactions and so produce thicker and more‐stable fibers. The second iteration aimed to increase the primary peptide–peptide interactions by increasing the overlap in the offset dimer and so promote the initial step in fiber formation. As judged by circular dichroism spectroscopy and transmission electron microscopy, both iterations improved fiber assembly and stability: the critical peptide concentration for assembly improved from 60 μM to 4 μM; the midpoint of thermal unfolding increased from 22 °C to 65 °C; and the salt tolerance improved from 75 mM to greater than 250 mM KCl. These improvements bring closer applications of the SAF system under physiological conditions, for example as a biocompatible material for 3D cell culture. In addition, ordered surface features were observed in the second‐ and third‐generation fibers compared with the original design. This indicates improved internal order in the redesigned fibers. In turn, this suggests a molecular mechanism for the improved stability and sheds light on the fiber‐assembly process.
Hybrid Solar Cells Using HgTe Nanocrystals and Nanoporous TiO2 Electrodes
Authors: Günes S. , Neugebauer H. , Sariciftci N. S. , Roither J. , Kovalenko M. , Pillwein G. , Heiss W. 
Published: April 2006

AbstractHgTe nanocrystals are demonstrated to increase the photon‐harvesting efficiency of hybrid solar cells over a broad spectral region between 350 and 1500 nm. Devices combining two solar cell concepts, a solid‐state nanocrystal‐sensitized solar cell and a nanocrystal/polymer‐blend solar cell, are described. These devices give incident photon to current efficiencies up to 10 % at around 550 nm monochromatic irradiation and short‐circuit current densities of 2 mA cm–2 under simulated AM1.5 (100 mW cm–2) illumination (AM: air mass).
Nanocrystalline TiO2 Photocatalytic Membranes with a Hierarchical Mesoporous Multilayer Structure: Synthesis, Characterization, and Multifunction
Authors: Choi H. , Sofranko A. C. , Dionysiou D. D. 
Published: April 2006

AbstractA novel sol–gel dip‐coating process to fabricate nanocrystalline TiO2 photocatalytic membranes with a robust hierarchical mesoporous multilayer and improved performance has been studied. Various titania sols containing poly(oxyethylenesorbitan monooleate) (Tween 80) surfactant as a pore‐directing agent to tailor‐design the porous structure of TiO2 materials at different molar ratios of Tween 80/isopropyl alcohol/acetic acid/titanium tetraisopropoxide = R:45:6:1 have been synthesized. The sols are dip‐coated on top of a homemade porous alumina substrate to fabricate TiO2/Al2O3 composite membranes, dried, and calcined, and this procedure is repeated with varying sols in succession. The resulting asymmetric mesoporous TiO2 membrane with a thickness of 0.9 μm exhibits a hierarchical change in pore diameter from 2–6, through 3–8, to 5–11 nm from the top to the bottom layer. Moreover, the corresponding porosity is incremented from 46.2, through 56.7, to 69.3 %. Compared to a repeated‐coating process using a single sol, the hierarchical multilayer process improves water permeability significantly without sacrificing the organic retention and photocatalytic activity of the TiO2 membranes. The prepared TiO2 photocatalytic membrane has great potential in developing highly efficient water treatment and reuse systems, for example, decomposition of organic pollutants, inactivation of pathogenic microorganisms, physical separation of contaminants, and self‐antifouling action because of its multifunctional capability.
Sources of mineralization and salinization of thermal groundwater of Jordan
Authors: Möller Peter , Geyer Stefan , Salameh Elias , Dulski Peter 
Published: April 2006

AbstractAccording to spider patterns five different types of thermal groundwater are distinguishable in Jordan. Each spider diagram comprises groups of elements which characterise soluble minerals of the aquifer such as halite, calcite, and gypsum, and leachable fractions of trace elements such as B, Ba, Br, Y, Cs, Rb, and U. In Jordan, mineralization of groundwater is largely controlled by dissolution of halite, carbonates, gypsum, and leaching diverse K‐bearing minerals. Caused by interaction with Neogene basalts, limestones are silicified and mineralogically altered. Groundwater from these aquifers significantly differs in composition from those of the unaltered limestone aquifers. The benefit of spider patterns is that they visualise (i) chemical differences in groundwater from essentially similar aquifer rock such as young, old or thermally altered limestones and (ii) chemical similarities of groundwater produced from different geological formations. In contrast to spider patterns, ionic ratios widely overlap and do not unequivocally allow grouping of groundwater. δ34S(sulfate) varies between –4 and +29 ‰. Low values prove the presence of oxidised sulfides either of igneous origin or from sedimentary rocks. The spread of δ34S is caused by mixing with marine sulfate. All analysed water from Paleozoic rocks is replenished from younger aquifers. Considerable transaquifer flow exists more or less all over the Jordan territory. Salinization of sandstone‐bound water along the rift escarpment is caused by a Na+‐K+‐SO42–‐HCO3– brine, whereas the wells Al Umari 1 and Wadi Araba 5 are affected by the presence of a Ca2+‐Cl– brine.