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A targeted development of safe medical products can be supported by design methods. This paper analyses which design methods are applied in the development of medical devices and whether they are adapted for considering medical devices’ special features (legal, human and technical issues). In particular, variety management, risk assessment and user-centered design for medical devices are examined. Typically, interdisciplinary risk assessment is methodically supported. Additionally, user-centered design methods for requirements assessment, design verification and design validation are applied.
Postoperative cognitive impairment is among the most common medical complications associated with surgical interventions – particularly in elderly patients. In our aging society, it is an urgent medical need to determine preoperative individual risk prediction to allow more accurate cost–benefit decisions prior to elective surgeries. So far, risk prediction is mainly based on clinical parameters. However, these parameters only give a rough estimate of the individual risk. At present, there are no molecular or neuroimaging biomarkers available to improve risk prediction and little is known about the etiology and pathophysiology of this clinical condition. In this short review, we summarize the current state of knowledge and briefly present the recently started BioCog project (Biomarker Development for Postoperative Cognitive Impairment in the Elderly), which is funded by the European Union. It is the goal of this research and development (R&D) project, which involves academic and industry partners throughout Europe, to deliver a multivariate algorithm based on clinical assessments as well as molecular and neuroimaging biomarkers to overcome the currently unsatisfying situation.
Measurements in the infrared wavelength domain allow direct assessment of the physical state and energy balance of cool matter in space, enabling the detailed study of the processes that govern the formation and evolution of stars and planetary systems in galaxies over cosmic time. Previous infrared missions revealed a great deal about the obscured Universe, but were hampered by limited sensitivity.
SPICA takes the next step in infrared observational capability by combining a large 2.5-meter diameter telescope, cooled to below 8 K, with instruments employing ultra-sensitive detectors. A combination of passive cooling and mechanical coolers will be used to cool both the telescope and the instruments. With mechanical coolers the mission lifetime is not limited by the supply of cryogen. With the combination of low telescope background and instruments with state-of-the-art detectors SPICA provides a huge advance on the capabilities of previous missions.
SPICA instruments offer spectral resolving power ranging from R ~50 through 11 000 in the 17–230 μm domain and R ~28.000 spectroscopy between 12 and 18 μm. SPICA will provide efficient 30–37 μm broad band mapping, and small field spectroscopic and polarimetric imaging at 100, 200 and 350 μm. SPICA will provide infrared spectroscopy with an unprecedented sensitivity of ~5 × 10−20 W m−2 (5σ/1 h)—over two orders of magnitude improvement over what earlier missions. This exceptional performance leap, will open entirely new domains in infrared astronomy; galaxy evolution and metal production over cosmic time, dust formation and evolution from very early epochs onwards, the formation history of planetary systems.
We successfully obtained the first optical spectra of the faint light echoes around Cassiopeia A and Tycho Brahe's supernova remnants (SNRs) with FOCAS and the Subaru Telescope. We conclude that Cas A and Tycho's SN 1572 belong to the Type IIb and normal Type Ia supernovae, respectively. Light echo spectra are important in order to obtain further insight into the supernova explosion mechanism of Tycho's SN 1572: how the Type Ia explosion actually proceeds, and whether accretion occurs from a companion or by the merging of two white dwarfs. The proximity of the SN 1572 remnant has allowed detailed studies, such as the possible identification of the binary companion, and provides a unique opportunity to test theories of the explosion mechanism and the nature of the progenitor. Future light-echo spectra, obtained in different spatial directions of SN 1572, will enable to construct a three-dimensional spectroscopic view of the explosion.
The Herschel Key Project SHINING performs a study of the ISM in star forming and active
infrared bright galaxies (starbursts, AGN, (U)LIRGs, interacting and low metallicity
galaxies) at local and intermediate redshifts. Here we present some surprising and
promising first results from parts of this programme, including spatially resolved PDR
diagnostics, line deficit diagnostics, and large scale molecular outflows traced by the OH
In standard diffraction experiments, ensembles of objects are characterized yielding
averaged, statistical properties (meaningful only if the ensemble is monodisperse).
Focused x-ray beams are used here to localize single nanostructures, identifying and
probing individual objects one by one. In a scanning mode, a 2-dimensional image of the
sample is recorded, which allows the reproducible alignment of a specific nanostructure
for analysis. The x-ray scattered signal is analyzed and modelled, to give access to the
shape, strain and composition inside the single object with sub-micron resolution.
Combination of x-ray microdiffraction technique with other micro-probe experiments on the
very same individual object (simultaneous coupling of x-ray diffraction measurements with
atomic force microscopy (AFM)) is also shown; we prove the possibility to interact with
the objects and to address elastic properties for individual nano-structures out of an
Seventy-eight Cotswold piglets weaned from sows receiving 0% or 2% conjugated linoleic acid (CLA)-supplemented rations from day 85 of gestation through lactation were allocated to nursery diets (ND) according to their dam’s lactation ration (LR) as follows (1) 0%-0% (0% CLA LR: 0% CLA ND, n = 17); (2) 0%-2% (0% CLA LR: 2% CLA ND, n = 17); (3) 2%-0% (2% CLA LR: 0% CLA ND, n = 23); and (4) 2%-2% (2% CLA LR: 2% CLA ND, n = 21). At 28 ± 2 days of age all piglets received an oral Escherichia coli K88+ (enterotoxigenic Escherichia coli, ETEC) challenge and were subsequently monitored for scour development and overall health until 36 ± 2 days of age, after which blood and tissue samples were collected. Piglet BW was not affected by dietary CLA supplementation to LR (P > 0.05). However, by day 36 piglets receiving 2% CLA-supplemented ND were significantly lighter (P < 0.05) than piglets receiving control diets. Average daily gain and feed efficiency were not affected by CLA supplementation. Average daily feed intake (ADFI) was greater for piglets weaned from 2% CLA-supplemented sows from day 17 to 28 (P < 0.05), otherwise ADFI was unaffected by dietary CLA supplementation (P > 0.05). The development of scours was less severe in piglets weaned from 2% CLA-supplemented sows at 8, 24, 48 and 56 h after ETEC challenge (P < 0.05). Intestinal coliform and lactic acid bacteria populations post challenge were not affected by CLA supplementation. However, cecal ammonia-N was numerically greatest in 0%-0% piglets compared to the other treatment groups, and the total volatile fatty acid production was numerically lower in 0%-0% and 0%-2% piglets compared to 2%-0% and 2%-2% piglets. In addition, piglets weaned from 2% CLA-supplemented sows had increased serum immunoglobulin A (P < 0.001) and G (P < 0.05) levels and reduced (P < 0.05) intestinal mucosal inflammation compared to piglets weaned from control sows. Although there were no obvious additional health effects observed when CLA was provided in ND, supplementing sow rations with 2% CLA from mid-gestation through weaning appears to have immune-stimulating carry-over effects post weaning. Thus, supplementing sow rations with CLA may be a practical strategy for enhancing passive immune transfer and improving the immune status and overall gut health of nursery piglets.
Progesterone is essential for maintaining pregnancy, and several authors have suggested that low peripheral concentrations of progesterone may be responsible for high rates of embryonic loss. The primary organ involved in the catabolism of progesterone is the liver, and cytochrome P450 2C and 3A sub-families account for a large proportion of this catabolism. Elucidating a mechanism to decrease progesterone catabolism, thereby increasing embryonic and uterine exposure to progesterone, seems a logical approach to ameliorate high rates of embryonic loss. The objectives of the current experiment were to determine the pattern of insulin secretion after supplementing feed with either sodium acetate or sodium propionate and to determine any association between the differential patterns of insulin secretion with the hepatic activity of cytochrome P450 2C and 3A and progesterone clearance. Sixteen ovariectomized ewes were fed 3 kg/day for 10 days of a diet consisting of 50% corn silage, 38% triticale haylage, 12% soybean meal and 600 ml of 3.5 M sodium acetate (energy control; n = 8) or 2.0 M sodium propionate (gluconeogenic substrate; n = 8). Equal portions of the ration (1 kg as-fed basis along with 200 ml of 3.5 M sodium acetate or 2.0 M sodium propionate) were offered three times daily at 0600, 1400 and 2200 h. Concentrations of insulin in plasma were determined immediately before feeding and at 15, 30, 60, 90, 120, 180, 240 and 300 min after feeding. Progesterone clearance from peripheral circulation (ng/ml per min) was measured by giving a 5 mg injection of progesterone into the left jugular vein and collecting blood via the right jugular vein at 0, 2, 4, 6, 8, 10, 15, 20 and 30 min afterwards. Liver biopsies were taken 1 h after feeding to determine cytochrome P450 2C and 3A activities. Insulin concentrations in ewes supplemented with sodium propionate were elevated at 15, 30 and 60 min after feeding compared to the sodium acetate group. Cytochrome P450 2C and 3A activities were decreased 1 h after feeding in the sodium propionate-treated ewes relative to sodium acetate. Insulin appears to down-regulate cytochrome P450 activity, which could be used to decrease the catabolism of progesterone during early gestation, thereby increasing peripheral concentrations of progesterone and, consequently, embryonic exposure to progesterone.
The bolometric luminosity of LFIR = 2×1012 L⊙ makes ISOSS J 15079+7247 one of the most luminous and unusual galaxies detected by the 170 μm ISOPHOT Serendipity Survey (ISOSS). The detection of CO (1-0) emission identifies a giant elliptical galaxy at redshift z = 0.2136 as the counterpart of the FIR source. The derived high gas mass of 3 × 1010 M⊙ favours the picture that the dust emission is associated with this elliptical galaxy. The ultraluminous IR emission can be explained by a hidden starburst in the center of the elliptical. This is supported by the strength of non-thermal radio continuum emission. The huge dust mass of 5×108 M⊙ corresponds to a visual extinction of AV ~ 1000 mag, being consistent with the non-detection of any signatures of a strong starburst in ISOSS J 15079+7247 in optical spectra.
The higher spatial resolution and sensitivity of ISO allowed several extragalactic surveys to be extended to greater depth than obtained with IRAS. With the extended wavelength range deep surveys were performed for the first time at wavelengths up to ~ 200 μm. They favour galaxy models with strong evolution. With ISO's new capabilities the spectral energy distributions of larger samples of ULIRGs in the local universe and those of quasars and radio galaxies were determined. These data are applicable as templates to the more distant universe. Foreground components from zodiacal light and cirrus to the intracluster dust emission were studied in connection with their separation from the extragalactic background radiation.
Background. Catatonia is a psychomotor syndrome that can be characterized by behavioural,
affective and motor abnormalities. In order to reveal further underlying pathophysiological
mechanisms of psychomotor disturbances in catatonia we investigated neuropsychological function
and regional cerebral perfusion (r-CBF) in a combined study.
Methods. Ten catatonic patients were investigated with Tc-99mECD brain SPECT and compared
with 10 psychiatric (similar age, sex, medication and underlying psychiatric diagnosis but without
catatonic syndrome) and 20 healthy controls. Neuropsychological measures included tests for
general intelligence, attention, executive functions and right parietal visual–spatial abilities.
Correlational analyses were performed between neuropsychological measures, catatonic symptoms
Results. Catatonic patients showed a significant decrease of r-CBF in right lower and middle
prefrontal and parietal cortex compared with psychiatric and healthy controls as well as
significantly poorer performance in visual–spatial abilities associated with right parietal function.
Correlational analysis revealed significant correlations between visual–spatial abilities and right
parietal r-CBF only in psychiatric and healthy controls but not in catatonic patients. In contrast,
attentional measures correlated significantly with motor symptoms, visual–spatial abilities and right
parietal r-CBF in catatonia only but not in psychiatric or in healthy controls.
Conclusion. Findings are preliminary but suggest right lower prefronto-parietal cortical dysfunction
in catatonia, which may be closely related to psychomotor disturbances.
Electrochemical Double Layer Capacitors (EDLC) for high energy and power density applications, based on glassy carbon (GO) electrodes, are being developed in our laboratory. In the context of this project, GC sheets were oxidized and investigated with Small Angle X-ray Scattering (SAXS), Electrochemical Impedance Spectroscopy (EIS) and Nitrogen Gas Adsorption (BET). During oxidation an active film with open pores is built on the surface of the GC. Upon oxidation, the internal volumetric surface area of the active film decreases, whereas the volumetric electrochemical double layer capacitance increases. We show that this effect is correlated with the opening, the growth and the coalescence of the pores.
Oxygen implanted silicon-on-insulator material, SIMOX, (Separation by IMplanted Oxygen) provides improved speed and radiation hardness over bulk silicon for integrated circuits which are built on the thin superficial Si layer above the buried oxide layer. A high quality superficial Si layer is required, but may be degraded by high defect densities of 109 to 1010 cm-2 in annealed SIMOX. Defect densities have been reduced down to 106cm-2 or less. They were achieved with a final high temperature annealing step (1300-1400°C) in conjunction with: a) high temperature implantation or; b) channeling implantation or; c) multiple cycle implantation. The defect structure developed during implantation, which is strongly affected by temperature, plays a significant role in the defect structure in the annealed material. In this work we are reporting on the effect of implantation temperature on defect formation and also some new details on the structure of the defects that are present.
High resolution electron microscopy (HREM) has been used to study the atomic arrangement of defects formed during high-dose oxygen implantation of silicon-on-insulator material. The effect of implantation parameters of wafer temperature, dose, and current density were investigated. Wafer temperature had the largest effect on the type and character of the defects. Above the buried oxide layer in the top silicon layer, HREM revealed that microtwins and stacking faults were created during implantation from 350–450°C. From 450–550°C, stacking faults were longer and microtwinning was reduced. From 550–700°C, a new type of defect was observed which had lengths of 40 to 140 nm and consisted of several discontinuous stacking faults which were randomly spaced and separated by two to eight atomic layers. We have referred to them as “multiply faulted defects” (MFDs). Beneath the buried oxide layer in the substrate region, the defects observed included stacking faults and ( 113 ) defects. The results indicated that some parts of the ( 1131 defects can assume a cubic diamond structure created through a twin operation across (115) planes. Details of the structure and formation mechanisms of MFDs and other defects will be discussed.
Silicon-on-insulator films were formed by ion implantation of oxygen and were treated with various annealing cycles at peak temperatures of 1150 °C, 1200 °C, and 1250 °C in a conventional diffusion furnace. The objective of this study was to examine the structural effects on samples with similar oxygen diffusion lengths (from 17 to 33 μm) achieved by annealing at different times and temperatures. The oxygen and silicon distributions, as well as the residual damage and precipitate size and distribution, were measured by Auger electron microscopy, Rutherford backscattering spectroscopy, and transmission electron microscopy. In agreement with previous findings, higher temperatures produced a larger and less defective, “precipitate-free” superficial Si region. The buried oxide layer thickened from 0.33 μm to a maximum of 0.43 μm as some precipitates were incorporated into the buried oxide while others adjacent to the buried oxide grew in size (up to 47 nm) and decreased in relative number. A new result of this systematic study of annealing conditions was that the peak temperature has a greater effect on the morphology and crystal quality of the superficial Si structure than does time at temperature. Structural changes for longer anneals at 1150 °C are not equivalent to shorter anneals at 1250 °C even though the diffusion length of oxygen for these treatments is the same.
The growth of thin Si films by RF glow discharge undergoes a transition from amorphous to microcrystalline as power density is increased. This results in a substantial change in the film's electrical conductivity and activation energy for electrical conduction. The RF glow discharge has been characterized in terms of plasma density, plasma potential and electron temperature with emissive Langmuir Probe measurements. The structural transition has been observed with a transmission electron microscope.
High dose ion implantation for materials synthesis in semiconductors is receiving increasing attention with the commercialization of medium and high current ion implanters. Surface and buried dielectric layers in silicon are being fabricated by high-dose implantation of oxygen, nitrogen, and carbon. Metallic silicides are being synthesized by implantation of metals such as cobalt and nickel. The evolution of a new phase or phases from a supersaturated solid solution during implantation occurs in a zone with increasing concentration which is also in a concentration gradient. Because of this, and the dynamic phenomena occurring, the whole process is quite complex. Additionally, a final, high temperature anneal to remove damage and to consolidate and stabilize the new phase(s) further complicates any analysis. There is no standard approach to analyze structural changes during high dose implantation and subsequent annealing, but it should be possible to approximate the phenomena based on traditional models for precipitation processes in solids. These processes include precipitate nucleation, growth, coarsening, coalescence, and dissolution. The most heavily studied process of materials synthesis by implantation is formation of a buried oxide layer in silicon (often referred to as SIMOX material).
Silicon-on-insulator (SOI) structure by high dose oxygen implantation (SIMOX) has excellent potential for use in radiation hardened and high speed integrated circuits. Device fabrication in SIMOX requires a high quality superficial Si layer above the buried oxide layer. Previously we reported on the effect of heater temperature, background doping, and annealing cycle on precipitate size, density, and location in the superficial Si layer. Precipitates were not eliminated with our processing conditions, but various authors have recently reported that high temperature annealing of SIMOX, from 1250°C to 1405°C, eliminates virtually all precipitates in the superficial Si layer. However, in those studies there were significant differences in implantation energy and dose and also annealing time and temperature. Here we are reporting on the effect of annealing time and temperature on the formation and changes in precipitates.
Scanning electron microscopy (SEM) of polymers at routine operating voltages of 15 to 25 keV can lead to beam damage and sample image distortion due to charging. These problems may be avoided by imaging polymer samples at a “crossover point”, which is located at low accelerating voltages (0.1 to 2.0 keV), where the number of electrons impinging on the sample are equal to the number of outgoing electrons emerging from the sample. This condition permits the polymer surface to remain electrically neutral and prevents image distortion due to “charging” effects. In this research we have examined Teflon (polytetrafluorethylene) samples and studied the effects of accelerating voltage and sample tilting on charging phenomena. We have also determined the approximate position of the “crossover point”.