Timing Recollision in Nonsequential Double Ionization by Intense Elliptically Polarized Laser Pulses.

We examine correlated electron and doubly charged ion momentum spectra from strong field double ionization of neon employing intense elliptically polarized laser pulses. An ellipticity-dependent asymmetry of correlated electron and ion momentum distributions has been observed. Using a 3D semiclassical model, we demonstrate that our observations reflect the subcycle dynamics of the recollision process. Our Letter reveals a general physical picture for recollision impact double ionization with elliptical polarization and demonstrates the possibility of ultrafast control of the recollision dynamics.

Haem is associated with thrombosis in neonates and infants undergoing cardiac surgery for congenital heart disease.

BACKGROUND: Haem levels are associated with thrombosis in a variety of diseases, as well as being a contributing cause of thrombotic events in animal models. MATERIALS AND METHODS: We retrospectively analyzed samples from 39 children who underwent cardiac surgery with cardiopulmonary bypass, including 15 children who developed a postoperative thrombosis and 24 controls. RESULTS: Patients who developed thrombosis postoperatively had statistically significant higher average haem levels over time (presurgery to 12 h postsurgery) compared to patients who did not develop thrombosis. CONCLUSION: Higher cell-free total haem levels are associated with a higher risk of thrombosis in a paediatric cardiac surgical cohort.

Nonsequential Double Ionization by Counterrotating Circularly Polarized Two-Color Laser Fields.

We report on nonsequential double ionization of Ar by a laser pulse consisting of two counterrotating circularly polarized fields (390 and 780 nm). The double-ionization probability depends strongly on the relative intensity of the two fields and shows a kneelike structure as a function of intensity. We conclude that double ionization is driven by a beam of nearly monoenergetic recolliding electrons, which can be controlled in intensity and energy by the field parameters. The electron momentum distributions show the recolliding electron as well as a second electron which escapes from an intermediate excited state of Ar^{+}.

ABO-immune complex formation and impact on platelet function, red cell structural integrity and haemostasis: an in vitro model of ABO non-identical transfusion.

BACKGROUND: Transfusion of ABO non-identical platelets has been associated with fatal haemolytic reactions, increased red cell transfusion needs and other adverse effects, but the practice of ABO matching in platelet transfusion is controversial. Immune complexes can be formed from the anti-A and/or anti-B antibodies and ABO soluble antigen(s) present in donor and recipient plasma after ABO non-identical transfusions. We hypothesized that these immune complexes affect recipient red cell structural integrity, platelet function and haemostasis. STUDY DESIGN AND METHODS: Haemolysis, platelet function and haemostatic function were assessed before and after incubation of recipient red cells, platelets and whole blood with normal saline controls, ABO-identical plasma controls or in vitro-generated ABO-immune complexes. RESULTS: ABO-immune complexes caused significantly increased haemolysis (P < 0·001), inhibition of platelet function (P = 0·001) and disruption of clot formation kinetics (P < 0·005) in both group A and O recipient samples. CONCLUSIONS: Substantial changes in platelet function, red cell integrity and haemostasis occur after in vitro exposure to immune complexes. These in vitro findings may explain, in part, previously observed associations of ABO non-identical platelet transfusions with adverse effects including increased red cell transfusion needs, organ failure and mortality.

Observation of electron energy discretization in strong field double ionization.

We report on the observation of discrete structures in the electron energy distribution for strong field double ionization of argon at 394 nm. The experimental conditions were chosen in order to ensure a nonsequential ejection of both electrons with an intermediate rescattering step. We have found discrete above-threshold ionization like peaks in the sum energy of both electrons, as predicted by all quantum mechanical calculations. More surprisingly, however, is the observation of two above-threshold ionization combs in the energy distribution of the individual electrons.

Percutaneous transluminal coronary angioplasty after thrombolytic therapy: a prospective controlled randomized trial.

In 162 patients with acute transmural myocardial infarction, combined intravenous and intracoronary thrombolytic therapy with streptokinase was initiated. In vessels that remained occluded, mechanical recanalization was performed with a 3F recanalization catheter (group I, n = 79) or a 4F Grüntzig balloon catheter (group II, n = 83). After reperfusion, intracoronary streptokinase was administered superselectively. After termination of streptokinase infusion, angioplasty was performed only in patients in group II. There was no difference between the groups in relation to sex, age, infarct location, creatine kinase levels and time between onset of symptoms and start of treatment. Initial coronary angiography showed an open vessel in 27 (34%) of 79 patients in group I and 21 (25%) of 83 patients in group II. The final reperfusion rate was 90% (71 of 79) in group I and 86% (71 of 83) in group II. Angioplasty was attempted in 69 of the 71 patients in group II with a success rate of 65% and an occlusion rate of 3%. During the hospital stay, reocclusion occurred in 14 (20%) of 71 patients in group I. After thrombolytic therapy, coronary luminal narrowing in group I was 75 +/- 17% in patients without and 87 +/- 6% in patients with reocclusion (p less than 0.05). In group II, reocclusion was found in 10 (14%) of 71 patients. After angioplasty, the degree of coronary stenosis in group II was reduced from 82 +/- 12 to 51 +/- 30% (p less than 0.001). Reocclusion was found in 3 (7%) of the 45 patients with successful angioplasty and in 7 (32%) of the 22 patients with unsuccessful angioplasty (p less than 0.01). Improvement in regional left ventricular function was observed only in patients from group II with anterior myocardial infarction. In conclusion, by combined medical and mechanical recanalization, the rate of coronary reperfusion can be increased and infarct time shortened, providing the possibility of full revascularization by angioplasty, with improvement of regional wall motion and reduction of the rate of reocclusion.

Anastomosis to the wrong vessel during off-pump bypass surgery via mini-thoracotomy.

Recently, minimally invasive coronary artery bypass graft operation has been established as a new treatment strategy for cardiac surgeons. We report on a patient who underwent off-pump coronary artery bypass graft operation through a mini-thoracotomy to the wrong coronary artery (first diagonal) with consecutive successful percutaneous transluminal coronary angioplasty of the vessel involved (left anterior descending coronary artery) to demonstrate a special risk that is associated with this kind of operation.

Estimation of age-dependent internal dose from radiopharmaceuticals.

The age-dependence of the radiation dose absorbed in a target organ or the total body is determined by the mass, size, shape and separation of the organs as well as by the metabolic behaviour of the radionuclide compound. Using values of the specific absorbed dose for adults, the age-dependent effective dose equivalents for 28 radiopharmaceuticals (62 radionuclides) were calculated by modifying the above mentioned values, considering radiation type, organ mass and source-target separation. From the results, the currently used mathematical models for the modification of values of specific absorbed doses in the adult prove to be of sufficient accuracy. In comparison with the few available values calculated by Monte Carlo-techniques, our method overestimates the specific absorbed fractions by a factor of four in the least favourable case. For practical radionuclide dose estimates, these deviations are of minor importance as long as the availability of reliable information on the metabolic behaviour of radionuclide compounds and radiopharmaceuticals as a function of age is extremely limited. Considering, however, both the parenteral administration and the short half-life of radionuclides used in paediatric nuclear medicine, this uncertainty in regard to the gastrointestinal absorption and the biological half-lives is of little consequence for the results of absorbed dose calculations.

Long-term follow-up of global and regional left ventricular function by two-dimensional echocardiography after thrombolytic therapy in acute myocardial infarction.

In order to evaluate changes in left ventricular volumes and regional left ventricular function after thrombolytic therapy in acute myocardial infarction serial two-dimensional echocardiography was performed during a follow-up of 2 years in 206 consecutive patients treated with streptokinase and adjunctive angioplasty in a randomized group of patients. Unexpected progressive left ventricular enlargement was detected both with and without angioplasty. In anterior wall infarction, end-diastolic volume index increased from 55 +/- 14 to 91 +/- 28 ml/m2 (+65%, P < 0.01) and end-systolic volume index increased from 31 +/- 11 to 55 +/- 23 ml/m2 (+79%, P < 0.01), whereas ejection fraction decreased from 45 +/- 9 to 41 +/- 7% (-9%, P = NS). Averaged regional anterior wall motion improved during the first 4 weeks (11 +/- 10 to 16 +/- 12%), but subsequently deteriorated (16 +/- 12 to 10 +/- 6, P < 0.05). The number of segments with pathological wall motion increased. Similar volumetric and regional wall motion data were demonstrated in inferior wall infarction. We believe this reflects a chronic ventricular remodelling phenomenon. This process takes place predominantly during the first 3 months, but continues over the whole follow-up period. Forty percent of the patients suffered symptoms of heart failure on long-term follow-up. Attenuation of progressive ventricular enlargement remains a therapeutic challenge in the long-term care of these patients. Angiotensin-converting enzyme inhibitors are promising agents in this regard.

[Absorbed dose for children and juveniles in nuclear medical diagnostics (author's transl)]. / Strahlenexposition von Kindren und Jugendlichen in der nuklearmedizinischen Diagnostik.

By means of special models and methods of calculation, values of the specific absorbed dose for the ICRP-reference man were corrected for the application to children and juveniles. For several commonly used radio-pharmaceuticals organ-dose values were calculated. For reasons of comparing the age dependence, values of the effective whole-body dose equivalent were computed. The age-dependence of these values mainly reflects the mass-dependence of the absorbed dose, so that for the administration of an age-dependence amount of radio-pharmaceutical the absorbed whole-body dose is nearly independent of the age, while the organ-dose may vary to a much greater extent.

Whole body content and turnover of Cs and K.

In persons who had accumulated radiocesium from the fallout of the Chernobyl nuclear reactor accident, the amount of radiocesium and radiopotassium was measured in the total body and in urine. The stable Cs content in the urine was determined at the same time by instrumental nuclear activation analysis. From the data obtained, the total body Cs pool was calculated to be 1500 micrograms, that of K 110 g. The Cs turnover rate was found to be 0.64%/d for men and 0.81 for women; the K turnover 2.4 and 2.7, respectively. The Cs:K ratio in the total body was 4 times higher than that in urine, demonstrating that, in relation to the intake, the body is able to accumulate more Cs than K.

Balloon coronary angioplasty in patients with acute myocardial infarction.

After successful thrombolysis, approximately 75% of all patients will have significant coronary stenosis, which can be dilated by means of percutaneous transluminal balloon angioplasty (PTCA). In a randomized control study, 95 of our patients (Group I) had thrombolysis alone, whereas 95 others (Group II) had thrombolysis and PTCA. Both groups were comparable with respect to age, sex, infarct location, and maximal creatine kinase (CK) value. The clinical outcome during the hospital phase was better in Group II, which had a reocclusion rate of 13%, a reinfarction rate of 5%, a lethal reinfarction rate of 2%, and a cardiac death rate of 7%, compared with respective rates of 20%, 13%, 7%, and 13% in Group I. Furthermore, in Group I, residual coronary stenosis immediately after thrombolysis (75% +/- 20%) did not improve significantly until the end of the hospital phase, when it decreased to 69% +/- 21%. In Group II, stenosis (78% +/- 16%) was improved by PTCA to 33% +/- 21%, and this improvement remained constant during the hospital phase (30% +/- 26%). In Group-II patients who had an unsuccessful PTCA, stenosis was approximately the same before dilatation (83% +/- 12%), after dilatation (80% +/- 17%), and at the control study (83% +/- 17%). The end-diastolic, end-systolic, and stroke volume indices, as well as the ejection fraction, also remained unchanged. In Group I, the number of pathologic wall segments (12.2 +/- 5.0) did not improve during the hospital phase (12.2 +/- 7.9), but in Group II, the improvement was significant (14.0 +/- 5.7 vs. 10.9 +/- 8.2) (p < 0.05). PTCA seems to improve the clinical outcome, reduce the infarction and mortality rates, and enhance myocardial perfusion and performance.

Thyroid doses resulting from the Ukraine Chernobyl accident--Part I: Dose estimates for the population of Kiev.

In the context of the radiation exposure of the Ukrainian population resulting from the Chernobyl accident, the quantification of the thyroid doses due to iodine incorporation is of special interest. This first part of a series of planned publications deals with the dose and risk estimation for Kiev citizens. Although these doses are expected to be considerably lower than those for some other regions of Ukraine, the investigations started with this population because the quantification of the thyroid doses due to iodine incorporation is of special interest. This first part of a series of planned publications deals with the dose and risk estimation for Kiev citizens. Although these doses are expected to be considerably lower than those for some other regions of Ukraine, the investigations started with this population because of the availability of rather reliable measurements and because of the size of this population. The methods developed allowed the estimation of individual thyroid doses. The average values of individual thyroid doses for five age groups (birth years 1983-1986, 1979-1982, 1975-1978, 1971-1974, and < 1971) are 104, 62, 19, 18, and 41 mGy, respectively. The collective thyroid doses were estimated as 83 x 10(3) person-Gy for those born before 1971 and as 38 x 10(3) person-Gy for younger inhabitants. The numbers of expected thyroid cancers in the whole Kiev population are 66 and 130, respectively.

Evaluation of the 131I thyroid-monitoring measurements performed in Ukraine during May and June of 1986.

After the Chernobyl accident in 1986, about 150,000 monitoring measurements were performed in Ukraine. From this data base, 40,000 measurements were selected for which the results of the reference-source measurements could be analyzed by statistical means. The majority of these measurements are of high quality. In this paper, the uncertainties introduced due to the variabilities of anatomic parameters and the measurement geometry are quantified by measurements using a thyroid-neck phantom. Parameters considered are the thyroid mass, the thickness of the tissue overlying the thyroid as well as the detector-neck distance, the orientation, and the horizontal and vertical position of the detector. The uncertainty introduced due to the variability of these factors corresponds to a coefficient of variation in the range of 25-40% for the measured activity.

The role of the ICRP in radiation protection--a view from industry.

It is the objective of this paper to discuss some aspects concerning the role and importance of the ICRP. Here, this is done with a background of practical radiation protection in industry. The author organises and controls radiation protection for a worldwide operating company, for which efficiently realised radiation safety is as relevant for its workplaces as for its products and services. According to the author's subjective observation, the ICRP has a decreasing importance in operational radiation protection. However, there are growing demands on the ICRP as it is the only basis for internationally compatible regulations and standards. It is the merit of the ICRP that an international comparison of legal protection systems and concepts should give a much more homogeneous picture than that for any other safety and protection issue. The most valuable asset of the ICRP is its credibility as a scientific authority solely committed to the effective protection of people. But its success also brings with it an obligation: there is an increasing need for more effective communication to non-experts. This and other expectations for the future are briefly discussed.

[Long-term follow-up of thrombolytic treatment of acute infarct in combination with acute and elective revascularization]. / Langzeitverlauf nach thrombolytischer Behandlung des akuten Infarktes in Kombination mit akuter und elektiver Revaskularisation.

From March 1983 to June 1986 in 206 patients with acute transmural myocardial infarction, combined intravenous and intracoronary therapy with streptokinase was initiated. After intravenous thrombolysis and randomization in two groups we performed a coronary angiography with selective intracoronary lysis. Infarct related vessels still occluded after intracoronary streptokinase application were opened mechanically in group I. In group II we performed additionally a percutaneous transluminal coronary angioplasty (PTCA) after mechanical recanalisation (occluded vessels) or after thrombolysis (open vessels). In 85 of 87 cases in group II, PTCA could be performed in the acute phase. Elective PTCA was performed in 22 patients of group I (21%) and in nine patients of group II (9%). Up to five years after myocardial infarction, coronary artery bypass grafting (CABG) was necessary in 22 patients (21%) of group I and in 23 patients (22%) of group II. Within four weeks after infarction CABG was performed in 32% and 17% of group I and II respectively. The six-year survival rate was 78% in group I and 82% in group II. Taken all patients together, the six-year survival rate was significantly higher (p = 0.002) for those with early reperfusion (less than or equal to 3.5 h). The survival rates of CABG-patients, PTCA-patients and patients without reperfusion were 91%, 74% and 65% respectively. Streptokinase thrombolysis results, combined with acute or elective PTCA and/or coronary bypass surgery, in a high six-year survival rate after acute transmural myocardial infarction. This rate is about 20% higher than ten years ago.

Influence of beta-aminopropionitril on media hypertrophy and baroreceptor reflex in normotensive and hypertensive rats.

Experiments were performed to investigate the antihypertensive action of beta-aminopropionitril (BAPN) in normotensive and hypertensive rats and to elucidate the role of media hypertrophy and arterial wall distensibility on baroreceptor reflex and blood pressure (BP) regulation. Normotensive Wistar-Kyoto rats (WKY), DOCA-salt hypertensive WKY, and stroke-prone spontaneously hypertensive rats (SHRSP) were treated with BAPN (100 mg/kg per day, intraperitoneally) for 10 weeks. The respective control groups (n = 10 per group) received 0.9% NaC1 instead of BAPN. In BAPN-treated groups the BP of DOCA-salt WKY (145 versus 170 mmHg) and SHRSP (170 versus 208 mmHg) was lower than that of controls at the end of the treatment period. In BAPN-treated rats, the medial cross-sectional area was reduced, postmortem distensibility of vascular wall was greater, and baroreceptor reflex, estimated from heart rate responses to BP changes, showed steeper regression curves. The BAPN-induced BP decrease in the hypertensive rats demonstrates that the level of sensitivity of the baroreceptor reflex is related to the mechanical properties of the arterial wall.

Application of ISO standard 27048: dose assessment for the monitoring of workers for internal radiation exposure.

Besides ongoing developments in the dosimetry of incorporated radionuclides, there are various efforts to improve the monitoring of workers for potential or real intakes of radionuclides. The disillusioning experience with numerous intercomparison projects identified substantial differences between national regulations, concepts, applied programmes and methods, and dose assessment procedures. Measured activities were not directly comparable because of significant differences between measuring frequencies and methods, but also results of case studies for dose assessments revealed differences of orders of magnitude. Besides the general common interest in reliable monitoring results, at least the cross-border activities of workers (e.g. nuclear power plant services) require consistent approaches and comparable results. The International Standardization Organization therefore initiated projects to standardise programmes for the monitoring of workers, the requirements for measuring laboratories and the processes for the quantitative evaluation of monitoring results in terms of internal assessed doses. The strength of the concepts applied by the international working group consists in a unified approach defining the requirements, databases and processes. This paper is intended to give a short introduction into the standardization project followed by a more detailed description of the dose assessment standard, which will be published in the very near future.