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Human coronary arteries in both early and advanced stages of atherosclerosis were studied for understanding the nature of Ca deposits in terms of their Ca/P mass ratio with the use of Eindhoven nuclear microprobe. The ratios observed differed appreciably from that of hydroxyapatite (2.15), which is commonly referred to as the Ca component in arteries affected by atherosclerosis. Very small granular calcified structures were found in an early stage. Broadly, two types of calcified structures were observed: the Ca/P ratio corresponding to the advanced stage (3.18) was found higher compared to those for the early stage (1.46–1.77). It has been argued that besides phosphates, the large Ca/P ratio corresponding to intense calcification may be due to a Ca deposit with a different anion (oxalate, hydroxide or even carbonate), while, the lower ratios may be due to an additional inorganic phosphate. The distribution of S/P ratios was used to account for enhanced deposition of lipid materials in the affected area at the expense of proteins.

A method is presented to correlate spatially trace elements with morphological features of atherosclerotic plaques by combining microprobe techniques and histological staining. Patterns from scanning transmission ion microscopy and morphology obtained from optical microscopy could be brought in fair to good agreement. It was possible to obtain element concentrations belonging to specific morphological features as indicated by optical microscopy.

Nonuniform seismic motion affects the seismic behavior of long-span bridges. Three main reasons for this nonuniformity have been identified. They are local soil conditions, wave passage, and incoherency effects. Other effects, such as extended source and attenuation, are relatively small. The importance of nonuniform seismic motions, especially for sensitive and important structures, has led to the development of several methods of analysis. These methods can be subdivided into two general categories, deterministic and stochastic. Because of the inherent uncertainty of the nonuniform seismic motions, deterministic methods, mainly time integration methods, can be computationally inefficient. Stochastic methods have been based mainly on modal analysis methods. The input/output are described in terms of either power spectral density or response spectra. This paper presents a direct frequency-domain method that is based on formulating the whole soil-structure problem. The use of this direct frequency-domain m...

The important recent progress in three-dimensional boundary-layer transition research is reviewed with emphasis on the crossflow instability that leads to transition on swept wings with a favorable pressure gradient. Following a brief overview of swept-wing instability mechanisms and the crossflow problem, a summary of the important findings of the 1990s is given. The discussion is presented from the experimental viewpoint, and where appropriate, relevant comparisons with CFD are drawn. The recent research conducted with distributed roughness is described in more detail in order to underscore the latest developments concerning nonlinear effects and transition control. Sommario. I recenti importanti sviluppi sullo studio della tansizione in uno strato limite tridimensionale sono esaminati con particolare attenzione alla instabilita trasversale che conduce alla transizione su ali a freccia con gradiente di pressione favorevole. Dopo una breve descrizione dei meccanismi di instabilita sulle ali a freccia viene dato un riassunto degli importanti progressi ottenuti negli anni '90. La discussione e presentata dal punto di vista sperimentale e, ove appropriato, sono riportati confronti con la simulazione numerica. La recente ricerca, condotta con rugosita distribuita,e descritta con maggiore dettaglio allo scopo di presentare gli ultimi sviluppi concernenti gli effetti non lineari ed il controllo della transizione.

International audience; The outcome of an infection is determined by a delicate balance between pathogen virulence and the ability of host to mount immune response. In this context, approaches that enable the study of mechanisms carried out by pathogens in vivo represent fundamental tools for a comprehensive view of infectious processes.

An experimental investigation of the parameter space of biologically inspired hover kinematics for flapping wings is conducted. The present research continues earlier work conducte at a Reynolds number of 4.8 x 10^3 and with a reduced frequency of 0.38. The kinematics considered are pitch and plunge motions based on the kinematics of the Agrius Convolvuli, which include a hover kinematic ignoring elevation angle, a hover kinematic incorporating a correction for elevation angle, and a harmonic pitch/plunge motion of the same amplitude. A parameter space exploration of these baseline motions is performed. First, the reduced frequency is increased to a value of 0.7. Second, a phase lag of 10%T and -10%T are introduced to study the effects of advanced and delayed rotation. Force measurements are reported and the results compared to the baseline motions. An increase in reduced frequency increases the average thrust coefficient substantially for all motions. The efficiency decreases slightly for all but the pure sinusoidal motion. Introducing a phase lag of 10% of the period changes the forces significantly. For delayed rotation thrust production and efficiency decrease by a large amount. Increases in thrust occur in the advanced rotation cases, although there is a penalty in efficiency.

This paper presents the results of an experimental study of the aerodynamics of an elliptical flap plate wing in pitch-plunge motion. Several wing motion kinematics are derived from the kinematics of the Agrius Convolvuli (hawk moth) in hover. The experiments are conducted at a Reynolds number of 4, 800 and reduced frequency of 0.38, which are typical of the hawk moth flight. Three cases are reported: the hawk moth kinematics in which the elevation angle is ignored, the hawk moth kinematics with a correction to account for elevation angle effects, and a harmonic pitch-plunge kinematic of the same frequency and amplitude as the hawk moth kinematics. In all cases the wing pivots about the leading edge. The experiments are performed in The University of Michigan water channel. The wing model used has a Zimmerman planform shape with aspect ratio 3.87. Phase averaged force measurements are reported. Average thrust coefficients of 2.79, 2.64 and 2.39, respectively, are measured for the three cases. The measured peak thrust coefficients are 5.0, 4.8 and 6.1, respectively. The propulsion figure of merit in hover was also measured and found to be 0.47, 0.48 and 0.49 for the three cases. The flow evolution was measured using PIV. The results show formation of Leading Edge Vortices (LEV) and Trailing Edge Vortices (TEV) at different phases of the motion which depend on the particular kinematics. The relation between LEV and TEV vortex evolution and force generation is discussed.

Sensors based on organic electronic devices are emerging in a wide range of application areas. Here we present a sensor platform using organic light emitting diodes (OLED) and organic photodiodes (OPD) as active components. By means of lamination and interconnection technology the functional foils with OLED and OPD arrays form an in-plane optical sensor platform (IPOS). This platform can be extended with a wireless data and signal processing unit yielding a sensor node. The focus of our research is to engage the node in a healthcare application, in which a bandage is able to monitor the vital signs of a person, a so-called Smart Bandage. One of the principles that is described here is based on measuring the absorption modulation of blood volume induced by the pulse (photoplethysmography). The information from such a bandage could be used to monitor wound healing by measuring the perfusion in the skin. The OLED and OPD devices are manufactured on separate foils and glass substrates by means of printing and coating technologies. Furthermore, the modular approach allows for the application of the optical sensing unit in a variety of other fields including chemical sensing. This, ultimately enables the measurement of a large variety of physiological parameters using the same bandage and the same basic sensor architecture. Here we discuss the build-up of our device in general terms. Specific characteristics of the used OLEDs and OPDs are shown and finally we demonstrate the functionality by simultaneously recorded photoplethysmograms of our device and a clinical pulseoximeter.

Although sarcomas are the most frequent primary malignant tumor of the heart, they very rarely involve only the left heart valves. A 72-year-old woman was diagnosed with a severe mitral valve disease and referred for cardiac surgery. Preoperative transthoracic echocardiography revealed a cardiac mass involving the mitral and aortic valves. The aortic valve had an unusual appearance, with a cystic mass protruding to the left ventricular outflow tract. The mitral valve apparatus was also involved, with chordal rupture. Extended resection and dual valve replacement was performed. A histological examination revealed an undifferentiated sarcoma. Postoperatively, neither chemotherapy nor radiotherapy therapy was used. Although most patients may benefit from adjunctive therapy, some respond well in the short term with only surgical resection, despite the poor prognosis of this rare entity.

The current paradigm reads that calcifications characterize the advanced and complex lesions in the atherosclerotic process. To explore the possibility that coronary artery wall calcifications already commence at an early stage of atherosclerosis, a combination of proton beam techniques with a (sub-) micrometer resolution, i.e., micro-proton induced X-ray emission, backward and forward scattering spectroscopy, was applied on human coronary arteries with lesions preceding overt atheromas. The detection limits of phosphorus and calcium in each separate pixel, 0.88*0.88 microm2 in size, were approximately 150 and 80 microg/g dry weight, respectively. Calcium distributions of entire coronary artery cross section were obtained, and calcifications were demonstrated at a preatheroma stage of the atherosclerotic process. The size of the microcalcifications varied between 1 and 10 microm. The composition of the microcalcifications was deduced from the calcium-to-phosphorus ratio. In order to quantify this ratio, the thickness of the specific X-ray absorber used for PIXE had to be accurately determined. Also, thick target PIXE calculations were performed and the method was validated. The calcium-to-phosphorus ratios of the microcalcifications were assessed with good accuracy and varied from 1.62 to 2.79, which corresponds with amorphous calcium phosphate.

Monitoring of personal wellbeing and optimizing human performance are areas where sensors have only begun to be used. One of the reasons for this is the specific demands that these application areas put on the underlying technology and system properties. In many cases these sensors will be integrated in clothing, be worn on the skin, or may even be placed inside the body. This implies that flexibility and wearability of the systems is essential for their success. Devices based on polymer semiconductors allow for these demands since they can be fabricated with thin film technology. The use of thin film device technology allows for the fabrication of very thin sensors (e.g. integrated in food product packaging), flexible or bendable sensors in wearables, large area/distributed sensors, and intrinsically low-cost applications in disposable products. With thin film device technology a high level of integration can be achieved with parts that analyze signals, process and store data, and interact over a network. Integration of all these functions will inherently lead to better cost/performance ratios, especially if printing and other standard polymer technology such as high precision moulding is applied for the fabrication. In this paper we present an optical transmission sensor array based on polymer semiconductor devices made by thin film technology. The organic devices, light emitting diodes, photodiodes and selective medium chip, are integrated with classic electronic components. Together they form a versatile sensor platform that allows for the quantitative measurement of 100 channels and communicates wireless with a computer. The emphasis is given to the sensor principle, the design, fabrication technology and integration of the thin film devices.

The introduction in the market of ubiquitous sensing applications relies heavily on the availability of affordable sensors. Key in the cost of a sensor is its modus of manufacture. In this paper a sensing scheme is presented, in which the signal transduction is based on an induced change in the optical path between an organic light emitting diode (OLED) and an organic photovoltaic (OPV) array. Using this platform, several aspects of cost efficient manufacturing technology are investigated. These aspects include the intrinsic printability of the active (OLED, responsive coating and OPV) components, which allows control of the local sensor functionality and sensitivity. It offers a large amount of freedom in sensor layout, while using relatively few process steps. Also investigated is the ability to realize the active devices on foil, which enables high throughput processing (e.g. in a reel-to-reel scheme). Moreover, the presented generic sensing scheme is of a modular design. It allows easy switching of the sensor functionality mostly by simply changing the transduction module. Since this does not affect the production parameters of the other components, these may be standardized, thus invoking favorable economies of scale.

Principal component analysis was applied to identify normal and pathological structures using combinations of levels of phosphorus, sulphur, chlorine, potassium and calcium in early stages of atherosclerotic coronary arteries. An inverse correlation was found between the combination of Ca–P, and that of S–Cl–K. This finding points towards the presence of smaller calcified deposits in an early phase of atherosclerosis in the human coronary artery. A possible location of cholesterol or some other carbon-based materials could also be identified. Further, a histogram method proved to be useful for characterising calcified structures of Ca/P mass ratio lower than that of hydroxyapatite. An empirical formula of (1− n )Ca 3 (PO 4 ) 2 · n A m (PO 4 ) is suggested to explain composition of these calcified structures.

Transition to turbulence in swept-wing flows has resisted correlation with linear theory because of its sensitivity to freestream conditions and 3-D roughness and because one of the principal instability modes quickly becomes nonlinear. In the face of such a formidable problem, two rather long-term fundamental efforts have been underway at DLR Gottingen and Arizona State University that address swept-wing transition. These efforts have been recently reviewed by Bippes (1997) and Reibert & Saric (1997). The present work is a continuation of studies on swept-wing boundary layers. In particular, we have taken advantage of the sensitivity to 3-D roughness and the modal nature of the instability in order to propose a particular control strategy.

Transition to turbulence in swept-wing flows has resisted correlation with linear theory because of its sensitivity to freestream conditions and 3-D roughness and because one of the principal instability modes quickly becomes nonlinear. In the face of such a formidable problem, two rather long-term fundamental efforts have been underway at DLR Gb'ttingen and Arizona State University that address swept-wing transition. These efforts have been recently reviewed by Bippes (1997) and Reibert and Saric (1997). Thus, the present work is a continuation of a series of studies on swept-wing boundary layers which have led to a better understanding of the transition process. In particular, we have taken advantage of the sensitivity to 3-D roughness and the modal nature of the instability in order to propose a particular control strategy.