bluuebunny/crossref_metadata_2025 huggingface dataset:
Lithium, potassium and sodium additions to cement pastes
Authors: Bentz D. P.
Published: April 2006

In the present study the influence of three alkali cations, namely lithium, potassium and sodium, on the hydration rates and the developing capillary pore structures of hydrating cement pastes was investigated. A quantitative examination of these effects was obtained by applying a set of experimental techniques that included isothermal calorimetry, loss-on-ignition measurements and low temperature calorimetry. Low temperature calorimetry was used specifically to assess the percolation (connectivity) of pore networks with various size entryways. Differences amongst the influences of the alkalis are highlighted and discussed in terms of their intrinsic atomic characteristics.
Performance of volcanic ash and pumice-based blended cements in sulphate and sulphate–chloride environments
Authors: Hossain K. M. A.
Published: April 2006

The deterioration of concrete structures due to sulphate and mixed sulphate—chloride in soils, groundwater and marine environments is a well-known phenomenon. The use of blended cements incorporating supplementary cementing materials and cements with low C3A content is becoming common in such aggressive environments. This paper presents the results of an investigation on the performance of volcanic ash (VA)- and finely ground volcanic pumice (VP)-based ASTM Type I and Type V (low C3A) blended cements (using 20% VA or VP as cement replacement) with varying immersion periods of up to 80 weeks in environments characterised by the conjoint presence of chlorides and sulphates. The effect of sulphate and sulphate—chloride environments on the strength and expansion characteristics of mortar specimens was evaluated. X-ray diffraction analysis and differential scanning calorimetry tests were also conducted to determine phase composition, pozzolanic activity and chloride binding of plain and blended cements. The performance of blended cements was found to be better in comparison with plain cements in terms of strength reduction and expansion characteristics and the performance was also found to depend on the type of cement (Type I or Type V). Results also indicate that the presence of chloride ions in the sulphate environment mitigates the sulphate attack in both plain and blended cements.
Predicting non-evaporable water loss of cement paste at elevated temperature
Authors: Tan T. H. , Ng L. P.
Published: April 2006

A research programme was conducted to predict non-evaporable water loss in hardened cement paste at elevated temperature. Existing models underestimate non-evaporable water loss for blended cement paste as the models are expressed as a function of mass of anhydrous cement. Thermogravimetric analysis and differential thermogravimetry were used to determine the decomposition profile of amorphous hydrates and portlandite. Analysis of test results showed that the decomposition profile of amorphous hydrates and portlandite was independent of mix design, degree of hydration and inclusion of pozzolana. An equation which addresses limitations in existing models is proposed to predict non-evaporable water loss at elevated temperature based on the volumetric ratio and decomposition profile of amorphous hydrates and portlandite in hardened cement paste. Both experimental and predicted non-evaporable mass losses were in accordance.
Surface Properties
Authors: Koberstein Jeffrey T.
Published: April 2006

The properties of polymer surfaces, and in particular the surface tension, are critical to many applications of polymeric materials. Surface tension controls the stability of thin films and the ability for polymers to wet a substrate, and is also an important factor in the adhesion of polymers to various substrates. The fundamental origin of surface tension is reviewed herein with emphasis on how surface tension depends on molecular parameters such as molecular weight and chemical constitution of the polymer. Theoretical and empirical correlations for the prediction of surface tension are presented to provide some basis for the molecular design of polymer surface properties. Since many commercial polymers are multicomponent in nature, the effects of compositional heterogeneity on surface tension are discussed for functional polymers and polymer blends. Finally, methods for experimental determination of polymer surface tension are discussed.
Evoked Potentials, Adaptive Filtering of
Authors: Chan F.H.Y. , Qiu W. , Poon P.W.F. , Ting K.H.
Published: April 2006

Evoked potentials (EPs) are time‐varying signals typically buried in relatively large background noise. Tracking variations in both the latency and the amplitude of EPs are important in quantifying properties of the nervous system. Adaptive filtering is a powerful tool for tracking such variations. In this article, EP signal estimation by adaptive filtering was introduced in the framework of an adaptive signal enhancer (ASE). Two inputs exist in ASE: the primary input, or the raw recorded data, that contains a signal plus noise, and the reference input that contains a signal related to, but not necessarily having the same waveform as the signal components in the primary input, and an additive noise, which is not correlated to the noise in the primary input. ASE requires a proper reference input signal for its optimal performance. Several effective reference input designs are introduced in this article. The results confirm the superior performance of ASE over the traditional ensemble average method.
Radiofrequency Energy, Biological Effects of
Authors: Foster Kenneth R.
Published: April 2006

This chapter reviews the interaction of radiofrequency (RF) energy with tissue, including mechanisms of interaction, principles of exposure assessment, and known or reported biological effects. Major therapeutic effects and potential hazards of RF energy are described, together with the basis for major exposure limits. Major areas of controversy about biological effects of radiofrequency energy are reviewed. A supplemental reading guide includes links to expert panel reports on health effects of RF energy.
Bio‐Optical Signals
Authors: Akin Ata
Published: April 2006

Neuroimaging techniques aim to provide information regarding the physiological changes that take place during activation of the brain in cognitive tasks. One such system, recently established, is the functional near‐infrared spectroscopy that uses light sources in the range of 650–950 nm to probe the underlying brain regions. The main absorbers of light within this range is the oxygenated hemoglobin (HbO2) and deoxygenated hemoglobin (Hb). The signal obtained from the prefrontal cortex of humans during cognitive tasks show that the increase of ([HbO2]) concentration surpasses that of ([Hb]), which means that regional cerebral blood flow to the activated region has increased to compensate for the demand in oxygen and glucose utilization. This article aims to present the underlying physical and physiological principles giving rise to biooptical signals of the brain.
Platelet‐Rich Plasma in Bone Repair
Authors: Ranly Don M. , McMillan Jacquelyn , Krause Wade F. , Lohmann Christoph H. , Boyan Barbara D. , Schwartz Zvi
Published: April 2006

Activation and degranulation of platelets releases cytokines that have effects on soft tissue and bone healing. Delivery of these growth factors to the site of wound healing may be achieved by preparation of a gel from platelet‐rich plasma, with or without the inclusion of the leukocyte fraction. This review describes the individual actions of the cytokines present in this gel, their effects on wound and bone healing, and the different methods of preparation of growth‐factor‐rich gels. Clinical results in the fields of bone and soft tissue healing, especially in the areas of maxillofacial and spinal surgery, are summarized.
Cell Surface Interactions
Authors: Wegener Joachim
Published: April 2006

The interaction of animal cells with technical surfaces is of increasing importance in many fields of biomedical and biotechnological science. The paper reviews the basic interactions that mediate the adhesion of cells on protein‐coated substrates and describes the experimental techniques that are used to study the interface between cell and surface.
Vascular and Capillary Endothelium
Authors: Brown Melissa , Wallace Charles S. , Truskey George A.
Published: April 2006

The endothelium is a monolayer of cells that line the inner lumen of all blood vessels. Endothelial cells respond to both mechanical forces created by blood flow and stimulatory molecules within the blood by producing vasoactive molecules that control vessel tone, thrombosis, and leukocyte adhesion. The healthy endothelium creates a nonthrombogenic surface, but when stimulated by injury, endothelial cells can produce cytokine or chemokine activators of the coagulation cascade or an inflammatory response. Vascular diseases such as atherosclerosis, diabetes, and sickle cell disease involve alterations of the function of the endothelium in which the cells promote vasoconstriction and a prothrombotic and proinflammatory state. While endothelial cells have the capacity to proliferate, endothelial progenitor cells derived from bone marrow and circulating in blood have the potential to regenerate injured regions of endothelium. These progenitor cells provide a new source of endothelium that may delay the onset of atherosclerosis and be used to generate new blood vessels.
Eye Movements
Authors: Enderle John
Published: April 2006

A description of eye movements is presented in this chapter. In addition, models of the saccadic system and smooth pursuit system are also presented. Five different types of eye movements exist: saccades, smooth pursuit, vestibular ocular eye movements, optokinetic eye movements, and vergence eye movements. Saccades are a fast eye movement used to acquire a target by placing the image of the target on the fovea. Smooth pursuit is a slow eye movement used to track a target as it moves by keeping the target on the fovea. The vestibular ocular movement is used to keep the eyes on a target during brief head movements. The optokinetic eye movement is a combination of saccadic and slow eye movements that keeps a full‐field image stable on the retina during sustained head rotation. Each of these movements is a conjugate eye movement, that is, movements of both eyes together driven by a common neural source. A vergence movement is a nonconjugate eye movement allowing the eyes to track targets as they come closer or move farther away.

The smooth pursuit system allows tracking of a slow‐moving target to maintain its position on the fovea. Models of the smooth pursuit have been developed using systems control theory, all involving a negative feedback control system that includes a time delay, controller, and plant in the forward loop with unity feedback. The oculomotor plant and saccade generator are the basic elements of the saccadic system. The oculomotor plant consists of three muscle pairs and the eyeball. The control of saccades is initiated by the superior colliculus (SC) and terminated by the cerebellar fastigial nucleus (FN), and involves a complex neural circuit in the mid brain. Both of these control models are for horizontal eye movements only.
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

Most 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

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

Photovoltaic 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.
Piezoelectric Actuators
Authors: Uchino Kenji
Published: April 2006

Piezoelectric actuators/sensors have been commercialized in various smart structures and systems such as precision positioners, adaptive mechanical dampers, and miniature ultrasonic motors. This article reviews the recent developments of piezoelectric actuators in terms of actuator materials, device designs, drive/control techniques, modeling, and applications.
Plasma Separation and Purification by Membrane
Authors: Jaffrin Michel Y. , Legallais Cecile
Published: April 2006

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.
Probability Distributions
Authors: Borror Connie
Published: April 2006

Probability distributions play an important role in engineering and the sciences In this chapter, several important probability distributions are presented and illustrated with examples. Discrete and continuous distributions are discussed and some of their applications in biomedical engineering are provided through examples.
Prosthetic Devices and Methods
Authors: Gard Steven
Published: April 2006

Limb 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

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.
Respiration Measurements
Authors: Fanelli Vito , Ferrari Andrea , Ranieri Vito Marco , Chiaia Bernardino
Published: April 2006

Mechanical ventilation is a life‐saving support that can induce even severe iatrogenic complications. Monitoring respiratory mechanics, patient‐ventilator interactions allows us to minimize the risks and facilitate withdrawal of ventilatory support.
Transport Across Endothelial Barriers, Modeling of
Authors: Fu Bingmei
Published: April 2006

Microvessel 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

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

Since 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

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

The 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

Two 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

HgTe 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

A 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

According 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.
CAPN3 mutations in patients with idiopathic eosinophilic myositis
Authors: Krahn Martin , Lopez De Munain Adolfo , Streichenberger Nathalie , Bernard Rafaëlle , Pécheux Christophe , Testard Hervé , Pena‐Segura José L. , Yoldi Eugenia , Cabello Ana , Romero Norma B. , Poza Juan J. , Bouillot‐Eimer Sandrine , Ferrer Xavier , Goicoechea Maria , Garcia‐Bragado Federico , Leturcq France , Urtizberea J. Andoni , Lévy Nicolas
Published: April 2006

Objective

Eosinophilic myositis (EM) constitutes a rare pathological entity characterized by eosinophilic infiltration of skeletal muscles, usually associated with parasite infections, systemic disorders, or the intake of drugs or L‐tryptophan. The exclusion of such causes defines the spectrum of idiopathic EM. Based on a protein analysis performed in one affected patient, we identified the gene encoding calpain‐3, CAPN3, as a candidate for a subset of idiopathic EM.

Methods

We screened CAPN3 for mutations using DHPLC and direct sequencing in six unrelated patients, recruited for EM diagnosed after histological examination of muscle biopsy samples, without any identified causative factor.

Results

We identified CAPN3 mutations in the six unrelated patients originally diagnosed with idiopathic EM.

Interpretation

Mutations in CAPN3 can cause EM. Thus, a subset of idiopathic EM is genetically determined, with an autosomal recessive mode of inheritance. Patients presented with a triad that appears to be indicative of CAPN3 mutations: (1) EM in the first decade, (2) elevated serum creatine phosphokinase levels (isolated or with little corresponding weakness), and (3) inconstant peripheral hypereosinophilia. However, that EM represents a distinct phenotype associated to CAPN3 mutations or, rather, an early histopathological picture of LGMD2A must be further evaluated. Our findings should be of interest toward further investigating the role of calpain‐3 in skeletal muscle. Furthermore, patients with idiopathic EM should undergo calpain‐3 protein analysis and be considered for subsequent molecular analysis of the CAPN3 gene.
Inhibiting matrix metalloproteinases with prinomastat produces abnormalities in fetal growth and development in rats
Authors: Younis Husam S. , Jessen Bart A. , Wu Ellen Y. , Stevens Gregory J.
Published: April 2006

BACKGROUND: Matrix metalloproteinases (MMPs) play key roles in remodeling of the extracellular matrix during embryogenesis and fetal development. The objective of this study was to determine the effects of prinomastat, a potent selective MMP inhibitor, on fetal growth and development. METHODS: Prinomastat (25, 100, 250 mg/kg/day, p.o.) was administered to pregnant female Sprague–Dawley rats on gestational days (GD) 6–17. A Cesarian section was carried out on GD 20 and the fetuses were evaluated for viability and skeletal and soft tissue abnormalities. RESULTS: Prinomastat treatment at the 250 mg/kg/day dose produced a decrease in body weight and food consumption in the dams. A dose‐dependent increase in post‐implantation loss was observed in the 100 and 250 mg/kg/day‐dose groups, resulting in only 22% of the dams having viable litters for evaluation at the 250 mg/kg/day dose. Fetal skeletal tissue variations and malformations were present in all prinomastat treated groups and their frequency increased with dose. Variations and malformation in fetal soft tissue were also increased at the 100 and 250 mg/kg/day doses. Prinomastat also interfered with fetal growth of rat embryo cultures in vitro. CONCLUSIONS: These data confirm that MMP inhibition has a profound effect on fetal growth and development in vivo and in vitro. Birth Defects Research (Part B) 77:95–103, 2006. © 2006 Wiley‐Liss, Inc.
A kinetic model to explain the maximum in α‐amylase activity measurements in the presence of small carbohydrates
Authors: Baks Tim , Janssen Anja E.M. , Boom Remko M.
Published: April 2006

The effect of the presence of several small carbohydrates on the measurement of the α‐amylase activity was determined over a broad concentration range. At low carbohydrate concentrations, a distinct maximum in the α‐amylase activity versus concentration curves was observed in several cases. At higher concentrations, all carbohydrates show a decreasing α‐amylase activity at increasing carbohydrate concentrations. A general kinetic model has been developed that can be used to describe and explain these phenomena. This model is based on the formation of a carbohydrate–enzyme complex that remains active. It is assumed that this complex is formed when a carbohydrate binds to α‐amylase without blocking the catalytic site and its surrounding subsites. Furthermore, the kinetic model incorporates substrate inhibition and substrate competition. Depending on the carbohydrate type and concentration, the measured α‐amylase activity can be 75% lower than the actual α‐amylase activity. The model that has been developed can be used to correct for these effects in order to obtain the actual amount of active enzyme. © 2006 Wiley Periodicals, Inc.
Closure effects on oxygen transfer and aerobic growth in shake flasks
Authors: Nikakhtari Hossein , Hill Gordon A.
Published: April 2006

Oxygen mass transfer in shake flasks is an important aspect limiting the culture of aerobic microorganisms. In this work, mass transfer of oxygen through a closure and headspace of shake flasks is investigated. New equations for prediction of kGa in shake flasks with closures are introduced. Using Pseudomonas putida, microbial growth on glucose (fast metabolism) and phenol (slow metabolism) in shake flasks with closures were studied, considering both substrate and oxygen restrictions. A combined model for oxygen mass transfer and microbial growth is shown to accurately predict experimental oxygen concentrations and oxygen yield factors during growth experiments more accurately than previous models. © 2006 Wiley Periodicals, Inc.
The Efficient Direct Synthesis of N,O‐Acetal Compounds as Key Intermediates of Discorhabdin A: Oxidative Fragmentation Reaction of α‐Amino Acids or β‐Amino Alcohols by Using Hypervalent Iodine(III) Reagents
Authors: Harayama Yu , Yoshida Masako , Kamimura Daigo , Wada Yasufumi , Kita Yasuyuki
Published: April 2006

Hypervalent iodine(III) reagents are readily available, easy to handle, and have a low toxicity and similar reactivities to those of heavy metal reagents, and hence they are used for various oxidative reactions. The oxidative cleavage of alkynes or carbonyl compounds by using bis(trifluoroacetoxy)iodo(III) pentafluorobenzene (C6F5I(OCOCF3)2) has been reported.1 Herein, the efficient direct synthesis of N,O‐acetal compounds as key intermediates of discorhabdin A, by the oxidative fragmentation reaction of α‐amino acids or β‐amino alcohols by using C6F5I(OCOCF3)2, is described.
Gd‐enhanced MR images of substrates other than water
Authors: Terreno Enzo , Botta Mauro , Dastrù Walter , Aime Silvio
Published: April 2006

This communication reports the dramatic relaxation enhancements that can be obtained upon the interaction of substrates like lactate, trifluorolactate and inorganic phosphate with the paramagnetic GdDO3A agent. This occurs thanks to the formation of kinetically labile ternary complexes in which the substrate nuclei are in close proximity to the paramagnetic center. It is demonstrated that heteronuclear 13C, 19F and 31P‐MR images can be obtained from phantoms containing the substrate in the millimolar concentration range. Copyright © 2006 John Wiley & Sons, Ltd.
Transfusion independence in patients with myelodysplastic syndromes
Authors: Balducci Lodovico
Published: April 2006

Anemia is the most common cytopenia associated with myelodysplastic syndromes (MDS). Current management relies on frequent red blood cell (RBC) transfusions and erythroid growth factors to alleviate symptoms. However, the dependence of patients with MDS on repeated RBC transfusions often results in significant clinical and economic consequences, poorer outcomes, and diminished health‐related quality of life. In addition, the intensity and duration of RBC transfusion dependence can influence responses to treatment after disease progression. Erythropoietic growth factors may alleviate the need for RBC transfusions in some patients with MDS, although only a minority of patients experience responses. Emerging treatment strategies to reduce or eliminate the need for RBC transfusions in patients with MDS include immunomodulating drugs, immunosuppressive therapy, and differentiating agents. The immunomodulating drug lenalidomide in patients who have MDS with 5q deletion is unique among emerging approaches, in that cytogenetic remitting activity and durable erythroid responses have been achieved. Newer treatments have the potential to improve the care of patients with MDS by alleviating the clinical, economic, and quality‐of‐life consequences of long‐term RBC transfusion dependence. Cancer 2006. © 2006 American Cancer Society.
Risk of invasive breast carcinoma among women diagnosed with ductal carcinoma in situ and lobular carcinoma in situ, 1988‐2001
Authors: Li Christopher I. , Malone Kathleen E. , Saltzman Babette S. , Daling Janet R.
Published: April 2006

BACKGROUND

Incidence rates of ductal carcinoma in situ (DCIS) and lobular carcinoma in situ (LCIS) have been rising, but little is known about which patients will develop invasive breast cancer or what types of tumors these patients may develop.

METHODS

By using Surveillance, Epidemiology and End Results (SEER) data, the authors evaluated how types of invasive breast cancers diagnosed among 37,692 DCIS and 4490 LCIS patients differed and how clinical characteristics influenced subsequent breast cancer risk.

RESULTS

Among DCIS patients, incidence rates of ipsilateral and contralateral invasive breast cancer were 5.4/1000 person‐years and 4.5/1000 person‐years, respectively; and among LCIS patients, incidence rates were 7.3/1000 person‐years and 5.2/1000 person‐years, respectively. LCIS patients were 5.3‐fold more likely than DCIS patients to develop invasive lobular carcinomas. Women whose DCIS had comedo histologic features or was poorly differentiated had 1.4‐fold and 2.0‐fold elevations in ipsilateral invasive breast cancer risk. Furthermore, among DCIS patients, 20‐49 year‐olds and black women and Hispanic white women had 1.6, 2.7, and 2.3‐fold elevated risks of Stage III/IV breast cancer compared with 50‐59 year‐olds and non‐Hispanic whites, respectively.

CONCLUSIONS

Screening young DCIS patients more frequently and improving the follow‐up care of blacks and Hispanic whites with DCIS may reduce their risk of advanced‐stage breast cancer. In addition, LCIS may be a precursor rather than just an ambiguous risk factor for invasive breast cancer, and, therefore, localized treatment for LCIS may be warranted. Given that incidence rates of DCIS and LCIS have been rising, investigations of these tumors should be continued to better understand their etiology and appropriate clinical management. Cancer 2006. © 2006 American Cancer Society.
After prostate cancer: Predictors of well‐being among long‐term prostate cancer survivors
Authors: Blank Thomas O. , Bellizzi Keith M.
Published: April 2006

BACKGROUND

Despite growing numbers of prostate cancer (PCa) survivors, to the authors' knowledge there is little research regarding how personality, coping, and treatment influence men's psychologic well‐being, as distinct from the often‐studied functional, health‐related quality of life. The purpose of this study was to examine how hope, optimism, use of coping strategies, and primary treatment predict well‐being, positive and negative affect, impact, depression, and adaptive changes among PCa survivors.

METHODS

A questionnaire tapping personality, primary treatment, and coping strategy predictor variables and outcome variables of both positive and negative aspects of well‐being was sent to 1–8‐year PCa survivors. The final sample included 490 men.

RESULTS

Basic univariate analyses demonstrated that the men reported being happy, hopeful, and positive, with low levels of negative outcomes. Regression analyses demonstrated that positive outcomes were influenced primarily by personality. Negative outcomes were found to be affected by both personality and coping strategies. Adaptive changes were the only ones found to be significantly affected by primary treatment.

CONCLUSIONS

Although longer‐term survivorship of PCa does not appear to be a highly traumatic experience, personality factors and the use of coping strategies years after treatment were found to introduce variability to well‐being in complex ways, differing in relation to positive and negative outcomes. Clinical attention should be given to how the experience of cancer fits within the larger context of an individual's attitudes, choices, and coping strategy orientation. Cancer 2006. © 2006 American Cancer Society.