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.

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.

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.

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 131I thyroid doses for the evacuees from Pripjat.

The thyroid doses of 49,360 inhabitants of Pripjat evacuated after the accident at Chernobyl were reconstructed. During their evacuation most of the evacuees passed through highly contaminated territories. The evaluation of a large-scale public survey showed that only about 50% of the evacuees had left the contaminated areas within 5 days and that 30% of them stayed there for more than 30 days. As a first step, the model of dose estimations was improved, and thyroid doses were assessed for the group of evacuees for whom the 131I activity in the thyroids was measured. The 131I incorporation during the first 5 days after the accident was described by a single-intake model (inhalation); later incorporations were assumed to be proportional to the radioiodine activity in milk. As a second step, the correlation between the calculated doses and individual parameters (place of residence in Pripjat, intake of stable iodine, and age at the time of the accident) was described by an empirical equation. This equation was applied to all evacuees who completed the questionnaires of the public survey. Previous dose assessments were found to overestimate the thyroid doses especially for the younger evacuees. On the basis of these estimations, collective doses and the resulting radiation risks for thyroid cancer were assessed for different age groups.

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.

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.

Thyroid dose assessment for the Chernigov region (Ukraine): estimation based on 131I thyroid measurements and extrapolation of the results to districts without monitoring.

Based on the results of 131I thyroid activity measurements in three districts of the Chernigov region (Ukraine), individual doses were calculated and an approach of the age dependence of the average thyroid exposure was derived. Using the relationships between the thyroid doses and the 137Cs deposition as well as the location relative to the Chernobyl Nuclear Power Plant (NPP), age-dependent average thyroid doses were extrapolated also for those settlements of this region where no monitoring measurements have been carried out. The highest doses were found in the west of the region with the lowest distance to the Chernobyl NPP. In this part, the highest mean of the thyroid dose in a settlement was 3.3 Gy for infants and 0.5 Gy for adults. The collective thyroid dose was 31,000 and 27,000 person-Gy for children and adults, respectively. Based on this assessment, 140 and 21 excess thyroid cancer cases are predicted for children and adults, respectively. In the years 1989 to 1991, in the whole contaminated territory of the Ukraine 0.4-1.2 cases per 100,000 children were observed. Although the absolute numbers are very small, this indicates the possibility of an increase in thyroid cancer morbidity among children. The same trend also seems to be indicated in the Chernigov region. A careful epidemiological study in the future is necessary to enable a final evaluation of radioinduced cancers in this region.

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.

[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.

Echocardiographic and angiographic evaluation of left ventricular function during percutaneous transluminal aortic valvuloplasty.

Transesophageal echocardiography was used to study the effect of the balloon inflation on left ventricular function in 20 patients with critical aortic stenosis undergoing balloon valvuloplasty. Balloon inflation caused an increase of end-diastolic (15% to 34%) and end-systolic (57% to 72%) left ventricular volume. Left ventricular wall stress increased from 30 +/- 10 x 10(3) dyn/cm2 at diastole and 121 +/- 40 x 10(3) dyn/cm2 at systole to 44 +/- 11 x 10(3) dyn/cm2 and 191 +/- 55 x 10(3) dyn/cm2, respectively, when the balloon was inflated (P less than 0.05). Turbulent regurgitant jet across the mitral valve increased from 15 +/- 2% to 25 +/- 3% during balloon inflation (P less than 0.01). Continued monitoring of left ventricular function after balloon deflation demonstrated prolonged enlargement of left ventricular volumes. Our data show that balloon inflation causes an increase of left ventricular volume and impairment of contraction. Increase of left ventricular wall stress--associated with a reduction of coronary blood flow, due to lower aortic pressure--could result in ischemic myocardial injury.

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.

Detection of dissection of the aortic intima and media after angioplasty of coarctation of the aorta. An angiographic, computer tomographic, and echocardiographic comparative study.

Balloon coarctation angioplasty (BCA) was performed in eight patients (five male and three female) who were 14-49 years old (mean, 27.3 years) with isolated discrete unoperated coarctation of the aorta (n = 7) and postoperative recoarctation (n = 1). BCA was successful in seven of eight patients, resulting in a decrease in the gradient (64 +/- 19 to 16 +/- 13 mm Hg, p less than 0.01), an increase in the diameter at the coarctation site (0.9 +/- 0.4 to 1.6 +/- 0.4 mm, p less than 0.01). Follow-up (6 months) has demonstrated continued gradient relief (6 +/- 9 mm Hg) and diameter increase (1.6 +/- 0.2 cm). Monitoring was performed by transesophageal echocardiography (TEE) during BCA, and before and after BCA angiography and after BCA computed tomography. In three of seven patients, immediately distal to the BCA site, intimal flaps (1-2 cm) could be detected by TEE but not by angiography or computed tomography. Follow-up TEE showed spontaneous healing in two and persistence in one patient. By TEE and computed tomography in one of eight patients during follow-up, intima and media dissection was found with pleural effusion and spontaneous healing. In one female patient, aortic dissection occurred after successful uneventful BCA, detected by TEE at the 6-month follow-up study and subsequently confirmed by biplane angiography, not detected by computed tomography and previous monoplane angiography. Because of the significant morbidity of BCA in this group of patients, its role in the management of adults with coarctation has yet to be determined. Further long-term follow-up studies will demonstrate whether the observed intima and media dissection by TEE after BCA are related to aneurysm formation.

Additive effects of enoximone and nitroprusside in unstable chronic heart failure.

In the present study, the safety and efficacy of the combined administration of intravenous nitroprusside and oral enoximone, an experimental compound with phosphodiesterase inhibitory properties, were evaluated. Ten patients with unstable chronic heart failure maintained on digitalis and diuretics were selected to receive enoximone because of their poor response to intravenous nitroprusside. For a mean peak dose of 115 micrograms min-1 nitroprusside, cardiac index increased from 1.8 +/- 0.4 to 2.0 +/- 0.4 l min-1 m-2, while pulmonary artery diastolic pressure and mean right atrial pressure decreased from 29 +/- 6 to 24 +/- 5 and from 15 +/- 6 to 11 +/- 3 mmHg respectively; mean arterial pressure and heart rate were unchanged. The addition of 1.6 mg kg-1 oral enoximone t.i.d. to nitroprusside resulted in a substantial improvement of cardiac function: cardiac index increased further to 2.8 +/- 0.5 l min-1 m-2 (P less than 0.001), pulmonary artery diastolic pressure and right atrial pressure decreased to 18 +/- 5 and 7 +/- 3 mmHg (P less than 0.01), respectively, while mean arterial pressure rose from 90 +/- 11 mmHg to 95 +/- 0 mmHg (P less than 0.05); heart rate was unchanged. The salutary haemodynamic response to combined nitroprusside-enoximone therapy persisted for more than 32 h, and cardiac performance remained improved on enoximone for a further 8 h despite the discontinuation of nitroprusside. No serious side-effects or changes in the arrhythmia profile were observed. The addition of oral enoximone to nitroprusside has beneficial haemodynamic effects in unstable chronic heart failure.