AMS-100: The Next Generation Magnetic Spectrometer in Space - An International Science Platform for Physics and Astrophysics at Lagrange Point 2.

The next generation magnetic spectrometer in space, AMS-100, is designed to have a geometrical acceptance of 100 m2 sr and to be operated for at least ten years at the Sun-Earth Lagrange Point 2. Compared to existing experiments, it will improve the sensitivity for the observation of new phenomena in cosmic rays, and in particular in cosmic antimatter, by at least a factor of 1000. The magnet design is based on high temperature superconductor tapes, which allow the construction of a thin solenoid with a homogeneous magnetic field of 1 Tesla inside. The inner volume is instrumented with a silicon tracker reaching a maximum detectable rigidity of 100 TV and a calorimeter system that is 70 radiation lengths deep, equivalent to four nuclear interaction lengths, which extends the energy reach for cosmic-ray nuclei up to the PeV scale, i.e. beyond the cosmic-ray knee. Covering most of the sky continuously, AMS-100 will detect high-energy gamma rays in the calorimeter system and by pair conversion in the thin solenoid, reconstructed with excellent angular resolution in the silicon tracker.

Extrapolation from ten sections can make CT-based quantification of lung aeration more practicable.

PURPOSE: Clinical applications of quantitative computed tomography (qCT) in patients with pulmonary opacifications are hindered by the radiation exposure and by the arduous manual image processing. We hypothesized that extrapolation from only ten thoracic CT sections will provide reliable information on the aeration of the entire lung. METHODS: CTs of 72 patients with normal and 85 patients with opacified lungs were studied retrospectively. Volumes and masses of the lung and its differently aerated compartments were obtained from all CT sections. Then only the most cranial and caudal sections and a further eight evenly spaced sections between them were selected. The results from these ten sections were extrapolated to the entire lung. The agreement between both methods was assessed with Bland-Altman plots. RESULTS: Median (range) total lung volume and mass were 3,738 (1,311-6,768) ml and 957 (545-3,019) g, the corresponding bias (limits of agreement) were 26 (-42 to 95) ml and 8 (-21 to 38) g, respectively. The median volumes (range) of differently aerated compartments (percentage of total lung volume) were 1 (0-54)% for the nonaerated, 5 (1-44)% for the poorly aerated, 85 (28-98)% for the normally aerated, and 4 (0-48)% for the hyperaerated subvolume. The agreement between the extrapolated results and those from all CT sections was excellent. All bias values were below 1% of the total lung volume or mass, the limits of agreement never exceeded ± 2%. CONCLUSION: The extrapolation method can reduce radiation exposure and shorten the time required for qCT analysis of lung aeration.

The effect of mechanical cleaning and thermal disinfection on light intensity provided by fibrelight Macintosh laryngoscopes.

The increased use of thermal decontamination procedures for fibrelight laryngoscope blades, to comply with international guidelines, will have considerable economical effects. We evaluated the effect of mechanical cleaning plus thermal disinfection at 90 degrees C, with or without subsequent steam sterilisation at 134 degrees C, on light intensity provided by fibrelight laryngoscopes. After mounting the blades in a special frame with a built-in light source, light intensity was measured using radiometer/photometer. In total, 14 blades provided by 11 companies were tested. The majority of fibrelight laryngoscope blades were fairly resistant to the damaging effects of machine washing plus disinfection at 90 degrees C (mean [range] reduction in light intensity 34.6%[2.1-78.3%]). However, when exposed to an additional sterilisation procedure at 134 degrees C, the majority of blades were unable to withstand the combined treatment for 300 cycles (mean [range] reduction in light intensity 86.5%[32.0-98.7%]). This study stresses the need for fibrelight laryngoscope blades which are more resistant to thermal decontamination procedures than those available at present.

Hyperperfusion of anterior cingulate gyrus in a case of paroxysmal nocturnal dystonia.

The authors report the clinical, EEG, and SPECT findings of a patient with nocturnal paroxysmal dystonia. Ictal and interictal scalp EEG showed epileptiform activity over both frontal lobes. Subtraction ictal SPECT co-registered to MRI indicated a bilateral significant hyperperfusion in the anterior part of the cingulate gyrus. These results support earlier electrophysiologic investigations by others suggesting that anterior cingulate epilepsy may manifest as nocturnal paroxysmal dystonia, and illustrate the usefulness of computer-assisted SPECT analysis.

Severe hypertension in children with renovascular disease.

Renovascular disease is an important cause of hypertension in children and is associated with considerable morbidity and mortality risks. Secondary hypertension is more common in children than in adults, with children accounting for 75% to 80% of cases. In 70% of secondary hypertension in children, the cause is fibromuscular hyperplasia. Other associated conditions are aorto-aortitis, the midaortic syndrome, and Williams-Bueren syndrome. Imaging techniques have an important role in the early discovery of renal artery stenosis. Although renal arteriography remains the definitive method, noninvasive and less invasive radiographic procedures such as ultrasonography with duplex Doppler scanning and radionuclide scintigraphy have been used as adjunct diagnostic tools in children. The authors describe three young children with renovascular hypertension in whom dynamic radionuclide scintigraphy with Tc-99m MAG3 played an essential role in the diagnosis of renovascular hypertension.

[Value of the 'non-diagnostic' lung scan--further classification as to the risk of pulmonary embolism not reliable]. / De waarde van de 'niet-diagnostische' longscan--verdere classificatie naar de kans op longembolie niet betrouwbaar.

OBJECTIVE: To determine to what extent the 'non-diagnostic' lung scans made because of a clinical suspicion of pulmonary embolism enable further determination of the risk of pulmonary embolism. DESIGN: Retrospective. METHOD: All non-diagnostic lung perfusion ventilation scans made in the Academic Medical Centre of Amsterdam in 1997 of 114 patients in succession (55 males and 59 females aged 27-85 years) were subjected to blind and independent re-evaluation by three observers (an experienced nuclear medicine expert, an experienced and an inexperienced intern) who, using a lung segment chart, estimated the risk of embolism as < 25%, 25-50%, 50-75% and > 75%. They did this first without and then with the chest X-ray. The findings were grouped on the basis of accordance or non-accordance with the pulmonary angiogram. The interobserver agreement was calculated by means of kappa statistics. RESULTS: Of 58 patients the lung scan could be compared with a chest X-ray and a pulmonary angiogram. In 43 patients with a normal angiogram the observers in an average of 50% of the scans estimated the risk of pulmonary embolism as < 25%, as against 25-50% in 27%, 50-75% in 9% and > 75% in 5%. In 15 patients with a deviant pulmonary angiogram, these figures were 22%, 38%, 20%, and 12%, respectively. The interobserver kappa for evaluation without chest X-ray was < or = 0.16, as against < or = 0.41% with the chest X-ray. CONCLUSIONS: A reliable classification of the risk of pulmonary embolism was not possible on the basis of non-diagnostic lung scans, regardless of whether the patient did or did not have pulmonary embolism. The interobserver variability was less when the lung scan was evaluated together with the chest X-ray, but even so it was unacceptably high.

Self-care agency: conceptualizations and operationalizations.

This article traces the interactive process between theory and research as it has been used to clarify the concept of self-care agency, a key concept in Orem's model of nursing. Theoretical constructions of self-care agency that have emerged in the work of Orem and the Nursing Development Conference Group are reviewed. Operational measures of self-care agency are described, particularly with regard to their underlying theoretical formulations. Factorial structures for some self-care agency instruments are related to the components of self-care agency in Orem's most recent conceptualization. Dimensions of self-care agency that are consistently supported by research studies of this phenomenon are identified.