Plaque-type blue nevus

Blue nevus may rarely appear in plaque form. It seems to be a benign and asymptomatic lesion, but because of its rarity, no definite prognosis can be given. Only through reporting of additional cases and their follow-up will the prognosis become clear.     

Rupture of Valsalva''s sinus of subacute development

In this study, the effects of forearm static exercise were determined on local blood flow and oxygen consumption in 15 normal individuals (NL) and their responses were compared with ten patients in congestive heart failure (CHF). Forearm blood flow was determined by a plethysmographic technique before and during 15% of maximum voluntary contraction of the forearm. Regional arterial and venous oxygen contents were sampled and forearm oxygen consumption calculated by the Fick principle. At rest, forearm blood flow was less in patients with heart failure than in normal individuals; however, this was compensated for by an increased oxygen extraction, thus maintaining forearm oxygen consumption at a normal level. In contrast, during static exercise, forearm blood flow failed to rise normally with heart failure (NL 9.31; CHF 4.35 ml/min-100 ml, P less than 0.001) and the increased oxygen extraction was not sufficient to maintain a normal forearm oxygen consumption (NL .82; CHF .44 ml/min-100 ml, P less than 0.01). Therefore, patients with congestive heart failure demonstrate regional circulatory and metabolic abnormalities during static exercise that are comparable to those present during dynamic exercise. Because of a limited ability of their skeletal muscle resistance vessels to respond to dilator stimuli, they have an attenuation of their exercise hyperemia which leads to an earlier shift to anaerobic metabolism.     

Influence of carbon source on nitrate removal by nitrate-tolerant Klebsiella oxytoca CECT 4460 in batch and chemostat cultures

The nitrate-tolerant organism Klebsiella oxytoca CECT 4460 tolerates nitrate at concentrations up to 1 M and is used to treat wastewater with high nitrate loads in industrial wastewater treatment plants. We studied the influence of the C source (glycerol or sucrose or both) on the growth rate and the efficiency of nitrate removal under laboratory conditions. With sucrose as the sole C source the maximum specific growth rate was 0.3 h-1, whereas with glycerol it was 0.45 h-1. In batch cultures K. oxytoca cells grown on sucrose or glycerol were able to immediately use sucrose as a sole C source, suggesting that sucrose uptake and metabolism were constitutive. In contrast, glycerol uptake occurred preferentially in glycerol-grown cells. Independent of the preculture conditions, when sucrose and glycerol were added simultaneously to batch cultures, the sucrose was used first, and once the supply of sucrose was exhausted, the glycerol was consumed. Utilization of nitrate as an N source occurred without nitrite or ammonium accumulation when glycerol was used, but nitrite accumulated when sucrose was used. In chemostat cultures K. oxytoca CECT 4460 efficiently removed nitrate without accumulation of nitrate or ammonium when sucrose, glycerol, or mixtures of these two C sources were used. The growth yields and the efficiencies of C and N utilization were determined at different growth rates in chemostat cultures. Regardless of the C source, yield carbon (YC) ranged between 1.3 and 1.0 g (dry weight) per g of sucrose C or glycerol C consumed. Regardless of the specific growth rate and the C source, yield nitrogen (YN) ranged from 17.2 to 12.5 g (dry weight) per g of nitrate N consumed. In contrast to batch cultures, in continuous cultures glycerol and sucrose were utilized simultaneously, although the specific rate of sucrose consumption was higher than the specific rate of glycerol consumption. In continuous cultures double-nutrient-limited growth appeared with respect to the C/N ratio of the feed medium and the dilution rate, so that for a C/N ratio between 10 and 30 and a growth rate of 0.1 h-1 the process led to simultaneous and efficient removal of the C and N sources used. At a growth rate of 0.2 h-1 the zone of double limitation was between 8 and 11. This suggests that the regimen of double limitation is influenced by the C/N ratio and the growth rate. The results of these experiments were validated by pulse assays.     

The predictors of quality care

Patients' perceptions of quality are important to the performance ratings, financial viability, and operational options afforded to purchasers of health care. Through TRICARE, the Department of Defense provides care for the more than 1.5 million active duty service members charged with the defense of the nation. As patients, these service members are typically incapable of assessing the technical quality of the care they receive. This study examines the attributes of health care delivery that define military patients' perceptions of quality and discusses the implications of these assessments.     

Design and validation of a rehabilitation robotic exoskeleton for tremor assessment and suppression.

Exoskeletons are mechatronic systems worn by a person in such a way that the physical interface permits a direct transfer of mechanical power and exchange of information. Upper limb robotic exoskeletons may be helpful for people with disabilities and/or limb weakness or injury. Tremor is the most common movement disorder in neurological practice. In addition to medication, rehabilitation programs, and deep brain stimulation, biomechanical loading has appeared as a potential tremor suppression alternative. This paper introduces the robotic exoskeleton called WOTAS (wearable orthosis for tremor assessment and suppression) that provides a means of testing and validating nongrounded control strategies for orthotic tremor suppression. This paper describes in detail the general concept for WOTAS, outlining the special features of the design and selection of system components. Two control strategies developed for tremor suppression with exoskeletons are described. These two strategies are based on biomechanical loading and notch filtering the tremor through the application of internal forces. Results from experiments using these two strategies on patients with tremor are summarized. Finally, results from clinical trials are presented, which indicate the feasibility of ambulatory mechanical suppression of tremor.     

Three-dimensional motion and reconstruction of coronary arteries from biplane cineangiography

A new approach is described for reconstructing coronary arteries from two sequences of projection images. The estimation of motion is performed on three-dimensional line segments (or centrelines), and is based on a ‘predictionprojection-optimization’ loop. The method copes with time varying properties, deformations and superpositions of vessels. Experiments using simulated and real data have been carried out. and the results found to be robust over a full cycle of a human heart. Local and global kinetic features can then be derived to obtain a greater insight on the cardiac functional state     

Influence de chargements cycliques de faible fréquence sur le comportement mécanique d'éprouvettes de mortier

Résumé Nous examinons le comportement du mortier soumis à des cycles de chargement de faible fréquence. Ceux-ci sont plus représentatifs des sollicitations que subit une structure que les essais habituels de fatigue. Dans cette étude le chargement eset monoaxial et le suivi des déformations longitudinales et transversales nous permet de définir le comportement rhéologique du mortier tant durant l'applicátion du chargement harmonique qu'après sa cessation. Nous déterminons les modifications dans le comportement mécanique du mortier que l'application du chargement cyclique entra?ne. Enfin, nous comparons l'évolution du mortier soumis à des cycles de chargement avec celle obtenue par un chargement stationnaire.

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Summary This research aims at defining the typical behaviour of a mortar subjected to a reference cyclic loading and comparing it with behaviour under constant load. Testing is carried out under monoaxial compression and low-cycle harmonic loading: 2 cycles per minute. Compared with routine fatigue testing, these conditions are more representative of load effects normally applied to structures. The minimum and maximum bounds of harmonic loading are respectively equal to 25% and 50% of ultimate load. The reference loading comprises 10 000 cycles. Studying the rheological behaviour of mortar subjected to harmonic loading has shown that at the beginning of cyclic loading the development of longitudinal deformation is twice as pronounced as that of transverse deformation. This difference tends to lessen when the number of cycles increases. The structural explanation of this phenomenon is linked to the progressive closing of free pores and the pressurizing of pore water. For a 6-month mortar the overall development of longitudinal deformation after the cycles is 17% of instantaneous deformation. Recovery stabilizes at 6% after 300 hours rest. After cycling we found that the mortar had undergone consolidation leading to linearisation of stress/strain curves, apparent shakedown, an increase in the modulus of longitudinal deformation and test piece volume decrease. Comparing the harmonic loading test and the constant load test underlines a much more pronounced development of longitudinal deformation in the latter and inversely a slighter deformation of transverse deformation. The loss of volume during creep is therefore greater than during cyclic loading of the same duration.