Magnetized plasma implosion in a snail target driven by a moderate-intensity laser pulse.

Optical generation of compact magnetized plasma structures is studied in the moderate intensity domain. A sub-ns laser beam irradiated snail-shaped targets with the intensity of about 1016 W/cm2. With a neat optical diagnostics, a sub-megagauss magnetized plasmoid is traced inside the target. On the observed hydrodynamic time scale, the hot plasma formation achieves a theta-pinch-like density and magnetic field distribution, which implodes into the target interior. This simple and elegant plasma magnetization scheme in the moderate-intensity domain is of particular interest for fundamental astrophysical-related studies and for development of future technologies.

Quantitative evaluation of active thermography using contrast-to-noise ratio.

Active thermography is an infrared-based technique for nondestructive testing of materials. It often uses advanced evaluation techniques based on temperature spatial and temporal changes. Results of active thermography are contrast differences, which indicate possible defects in an inspected material. These differences cannot be quantified by temperature. This contribution is focused on the active thermography results' evaluation parameters and the contrast-to-noise ratio method, which can be used for quantitative evaluation of the results. Different result interpretation procedures are introduced. The influence of a selection method for indication and reference regions and the effect of image scaling on inspection results are discussed.

Synchronizing single-shot high-energy iodine photodissociation laser PALS and high-repetition-rate femtosecond Ti:sapphire laser system.

A system of precise pulse synchronization between a single-shot large-scale laser exploiting an acousto-optical modulator and a femtosecond high repetition rate laser is reported in this article. This opto-electronical system has been developed for synchronization of the sub-nanosecond kJ-class iodine photodissociation laser system (Prague Asterix Laser System-PALS) with the femtosecond 25-TW Ti:sapphire (Ti:Sa) laser operating at a repetition rate 1 kHz or 10 Hz depending on the required energy level of output pulses. At 1 kHz synchronization regime, a single femtosecond pulse of duration about 45 fs and a small energy less than 1 mJ are exploited as a probe beam for irradiation of a three-frame interferometer, while at 10 Hz repetition rate a single femtosecond pulse with higher energy about 7-10 mJ is exploited as a probe beam for irradiation of a two-channel polaro-interferometer. The synchronization accuracy ±100 ps between the PALS and the Ti:Sa laser pulses has been achieved in both regimes of synchronization. The femtosecond interferograms of laser-produced plasmas obtained by the three-frame interferometer and the femtosecond polarimetric images obtained by the two-frame polaro-interferometer confirm the full usefulness and correct functionality of the proposed method of synchronization.

Active thermography inspection of protective glass contamination on laser scanning heads.

Industrial lasers are an expanding technology of welding and other materials processing. Lasers with optical scanning heads are often used, as these provide more versatility, accuracy, and speed. The output part of the scanning head is covered by a protective glass, which might get contaminated by various particles from the laser processing. This decreases the transmissivity of the glass, and it can affect the production quality. The contamination needs to be checked regularly, but a visual inspection might not always be effective. This paper proposes two alternative methods of inspecting the protective glass: flash-pulse active thermography, and laser active thermography. They are based on the thermal excitation of the glass and measuring the response with an infrared camera. The experimental setup and practical results are described and the advantages and disadvantages are discussed. The presented methods are proven to be effective in detecting the contamination of the glass.

Measurement of the target current by inductive probe during laser interaction on terawatt laser system PALS.

Measurements of the return-current flowing through a solid target irradiated with the sub-nanosecond kJ-class Prague Asterix Laser System is reported. A new inductive target probe was developed which allows us measuring the target current derivative in a kA/ns range. The dependences of the target current on the laser pulse energy for cooper, graphite, and polyethylene targets are reported. The experiment shows that the target current is proportional to the deposited laser energy and is strongly affected by the shot-to-shot fluctuations. The corresponding maximum target charge exceeded a value of 10 µC. A return-current dependence of the electromagnetic pulse produced by the laser-target interaction is presented.

Generation of high currents of carbon ions with the use of subnanosecond near-infrared laser pulses.

Emission of carbon currents reaching values up to 2 A/cm(2) at a distance of 1 m from the laser ion source driven by the subnanosecond Prague Asterix Laser System operated at a fundamental wavelength of 1315 nm is reported. Graphite targets were exposed to intensities up to 5x10(16) W/cm(2) varying both the laser energy and the position of the laser beam focus with respect to the target surface. The maximum energy gain of carbon ions was approximately = 1 MeV/u. At high laser intensities the shape of time-of-flight spectra is also formed by plasma outbursts, whose growth correlates with the oscillatory self-focusing of the laser beam.

Laser generation of Au ions with charge states above 50+.

Results of recent studies on highly charged Au ion generation, using the intense long pulses of the PALS high power iodine laser (lambda=1.315 microm, E(L)=800 J400 ps), operating under variable experimental conditions (1omega, 3omega, varying target thickness and changing focus positions), are presented. Both the ion collectors and the ion electrostatic analyzers were applied for the identification of ions in a large distance from the target. The time-of-flight collector signals were treated by a means of peak deconvolution assuming a shifted Maxwell-Boltzmann form of the constituent ion current peaks. Attention was paid to the influence of pulse precursor, which becomes evident, especially, if using thinner targets and 1omega. The results for 3omega point to the presence of several groups of ions with the highest recorded charge state Au(53+).

Hugoniot data of plastic foams obtained from laser-driven shocks.

In this paper we present Hugoniot data for plastic foams obtained with laser-driven shocks. Relative equation-of-state data for foams were obtained using Al as a reference material. The diagnostics consisted in the detection of shock breakout from double layer Al/foam targets. The foams [poly(4-methyl-1-pentene) with density 130 > rho > 60 mg/cm3] were produced at the Institute of Laser Engineering of Osaka University. The experiment was performed using the Prague PALS iodine laser working at 0.44 microm wavelength and irradiances up to a few 10(14) W/cm2. Pressures as high as 3.6 Mbar (previously unreached for such low-density materials) where generated in the foams. Samples with four different values of initial density were used, in order to explore a wider region of the phase diagram. Shock acceleration when the shock crosses the Al/foam interface was also measured.

Hugoniot data for carbon at megabar pressures.

We present an experimental point for the carbon equation of state (EOS) at megabar pressures, obtained by laser-driven shock waves. The rear side emissivity of "two-materials two-steps" targets (Al-C) was recorded with space and time resolution and, by applying the impedance mismatch method, allowed a direct determination of relative EOS points. Experiments were performed at the PALS and LULI laboratories using carbon samples with two different values of initial density, in order to explore a wider region of the phase diagram. Previously unreached pressures were obtained. The results are compared with previous experiments and with available theoretical models and seem to show a high compressibility of carbon at megabar pressures.

Distribution of Ca.LSU intron and acid protease production by Candida albicans strains isolated from gastrointestinal tract of diabetes children.

The association between the presence of self-splicing intron Ca.LSU and proteolytic activity of Candida albicans isolates was tested. Study included 95 C. albicans strains isolated from gastrointestinal tract of diabetes children. The strains with the intron (genotype B) displayed a significantly higher proteolytic activity (385.2+/-192U/L) than did strains without intron (genotype A) (119+/-115U/L) (p = 0.0000048).

Ablation pressure scaling at short laser wavelength.

The ablation pressure at a 0.44-microm laser wavelength has been measured at irradiance up to 2 x 10(14) W/cm(2). The diagnostics consisted in the detection of shock breakout from stepped Al targets. By adopting large focal spots and smoothed laser beams, the lateral energy transport and "drilling effects" have been avoided. The measured scaling shows a fair agreement with analytical models.

[Duration of surgery in osteosynthesis of fractures of the trochanter]. / Operacní cas pri osteosyntéze zlomenin trochanterického masivu.

PURPOSE OF THE WORK: To analyze duration of surgery in individual types of internal fixation of fractures of the trochanteric massif and identify factors which have an impact on it. MATERIAL: Analysis covered a group of 137 patients treated with Ender nailing (EN), 314 patients by means of Dynamic Hip Screw (DHS), 74 patients by means of Gamma nail, 37 patients by means of Proximal Femoral Nail (PFN) and 13 patients by means of 130 degrees angled blade plate. The groups of patients included basicervical femoral neck fractures (29 cases), peritrochanteric and subtrochanteric fractures. Peritrochanteric fractures were evaluated according to Kyle classification, types I and II as stable (174 cases), type III unstable (159 cases) similarly as type IV (peri/subtrochanteric fractures or comminuted fractures of the whole trochanteric massif--35 cases). High subtrochanteric fractures (55 cases) were evaluated after Seinsheimer. From the viewpoint of AO/ASIF classification they were 31A1, 31A2, 31A3 fractures. EN was indicated mainly in Kyle I through IV fractures, DHS for basicervical fractures and Kyle I through III fractures, Gamma nail for Kyle I through IV fractures and high subtrochanteric fractures, PFN mainly for high subtrochanteric fractures and Kyle III fractures, 130 degrees angled blade plate was indicated only for stable peritrochanteric Kyle I fractures. RESULTS: The average duration of surgery, i.e. starting from the skin incision until the suture of the wound, was in DHS 47 min., in EN 52 min., in 130 degrees angled blade plate 54 min., in PFN 58 min. and in Gamma nail 70 min. The shortest time intervals were achieved in stable peritrochanteric fractures of Kyle I and II (EN, DHS, Gamma), the longest ones in high subtrochanteric fractures (Gamma, PFN). The impact of the learning curve was analyzed in DHS. In 1995 the average duration was 70 min. (35 patients/year), in 2000 already only 39 min. (123 patients/year). DISCUSSION: If we wish to make a serious evaluation of the duration of surgery of any method we must not forget that apart from it there is a whole number of other factors by which it is influenced. In case of proximal femur it is the type of fracture, the number and experience of surgeons, mastering the learning curve, annual frequency of surgeries at the respective Department as well as variation within the surgical technique (e.g. in DHS the number of distal locking and the number of locking screws, etc.) A significant role in this study was also played by the development of internal fixation at the Department of the authors. For instance, considerably shorter duration of surgery as well as minimum of complications in PFN were achieved thanks to mastering of the learning curve on the Gamma nail which we had started to use 3 years before. An objective evaluation requires also a sufficient number of cases in order to eliminate errors caused by low numbers and other variable factors. CONCLUSION: Surgery duration data which we present are comparable with the values included in the world literature. It applies not only to the duration of surgery in individual implants but also in individual types of proximal femur fractures. At present at our Department the average duration of surgery ranges in dependence on the applied implant, type of fracture and skills of the surgeon between 30 and 60 minutes. Relatively shortest duration can be achieved in DHS, in Gamma nail and PFN the duration is slightly longer. However, the duration of surgery is only a supporting factor. Of much greater importance for the patient is the quality of the surgery. Thus favouring any method only on the basis of the duration of surgery is absolutely irrelevant.

Change in heart rate and heart rate variability during treatment for depression in patients with coronary heart disease.

OBJECTIVE: Major depression is a common problem in patients with coronary heart disease (CHD) and is associated with an increased risk for cardiac morbidity and mortality. It is not known whether treating depression will improve medical prognosis in patients with CHD. Depression is also associated with elevated heart rate and reduced heart rate variability (HRV), which are known risk factors for cardiac morbidity and mortality that may explain the increased risk associated with depression. The purpose of this study was to determine whether treatment for depression with cognitive behavior therapy (CBT) is associated with decreased heart rate or increased HRV. METHODS: Thirty depressed patients with stable CHD, classified as either mildly or moderately to severely depressed, received up to 16 sessions of CBT. The 24-hour heart rate and HRV were measured in these patients and in 22 medically comparable nondepressed controls before and after treatment of the depressed patients. RESULTS: Average heart rate and daytime rMSSD (reflecting mostly parasympathetic activity) improved significantly in the severely depressed patients, but remained unchanged in the mildly depressed and the control patients. However, only rMSSD improved to a level comparable to the control patients. None of the remaining indices of HRV showed improvement. CONCLUSIONS: The results suggest that treating depression with CBT may reduce heart rate and increase short-term HRV. Thus, CBT may have a beneficial effect on a risk factor for mortality in depressed patients with coronary heart disease. A randomized, controlled study is needed to confirm these findings.

Severe depression is associated with markedly reduced heart rate variability in patients with stable coronary heart disease.

OBJECTIVE: The purpose of this study was to investigate the relationship between depression and heart rate variability in cardiac patients. METHODS: Heart rate variability was measured during 24-hour ambulatory electrocardiographic (ECG) monitoring in 40 medically stable out-patients with documented coronary heart disease meeting current diagnostic criteria for major depression, and 32 nondepressed, but otherwise comparable, patients. Patients discontinued beta-blockers and antidepressant medications at the time of study. Depressed patients were classified as mildly (n = 21) or moderately-to-severely depressed (n = 19) on the basis of Beck Depression Inventory scores. RESULTS: There were no significant differences among the groups in age, gender, blood pressure, history of myocardial infarction, diabetes, or smoking. Heart rates were higher and nearly all indices of heart rate variability were significantly reduced in the moderately-to-severely versus the nondepressed group. Heart rates were also higher and mean values for heart rate variability lower in the mildly depressed group compared with the nondepressed group, but these differences did not attain statistical significance. CONCLUSION: The association of moderate to severe depression with reduced heart rate variability in patients with stable coronary heart disease may reflect altered cardiac autonomic modulation and may explain their increased risk for mortality.

Major depression, heart rate, and plasma norepinephrine in patients with coronary heart disease.

BACKGROUND: Although it is now well established that psychiatric depression is associated with adverse outcomes in patients with coronary heart disease (CHD), the mechanism underlying this association is unclear. Elevated heart rate (HR) and plasma norepinephrine (NE), possibly reflecting altered autonomic nervous system activity, have been documented in medically well depressed psychiatric patients, and this pattern is associated with increased risk for cardiac events in patients with CHD. The purpose of this study was to determine whether autonomic nervous system activity is altered in depressed CHD patients. METHODS: HR, plasma NE, and blood pressure (BP) were measured in 50 depressed and 39 medically comparable nondepressed CHD patients at rest and during orthostatic challenge. RESULTS: Resting HR (p = .005), and the change from resting HR at 2, 5, and 10 min after standing (p = .02, .004, and .02, respectively), were significantly higher in the depressed than in the nondepressed patients. There were no differences between the groups in NE or in BP at rest, or in standing minus resting change scores at any time during orthostatic challenge (p < .05). CONCLUSIONS: Depression is associated with altered autonomic activity in patients with CHD, as reflected by elevated resting HR and an exaggerated HR response to orthostatic challenge. Previously reported differences in NE levels between depressed and nondepressed patients were not replicated.

Functional analysis of three adjacent open reading frames from the right arm of yeast chromosome XVI.

A 7.24 kb genomic DNA fragment from the yeast Saccharomyces cerevisiae chromosome XVI was isolated by complementation of a new temperature-sensitive mutation tsa1. We determined the nucleotide sequence of this fragment located on the right arm of chromosome XVI. Among the three, complete open reading frames: YPR041w, YPR042c and YPR043w contained within this fragment, the gene YPR041w was shown to complement the tsa1 mutation and to correspond to the TIF5 gene encoding an essential protein synthesis initiation translation factor. The YPR042c gene encodes a hypothetical protein of 1075 amino acids containing four putative transmembrane segments and is non-essential for growth. The gene YPR043c encoding the 10 kDa product, highly similar to the human protein L37a from the 60S ribosomal subunit, was found to be essential and a dominant lethal. We conclude that three tightly linked yeast genes are involved in the translation process.

Adherence to a prophylactic medication regimen in patients with symptomatic versus asymptomatic ischemic heart disease.

Although angina pectoris is the most common symptom of coronary artery disease, some patients do not experience angina during ischemic episodes. The effects of asymptomatic (silent) heart disease on patient self-management have rarely been studied. Studies of other patient populations with asymptomatic illnesses indicate that patients with silent myocardial ischemia might adhere less well to a prophylactic medication regimen than would those with symptomatic ischemia. Depression, a state associated with poor adherence to medical regimens is more common among patients with symptomatic ischemia. For prevention of thromboembolic events, 37 patients with documented ischemic heart disease who denied having anginal symptoms and 28 patients who reported almost daily symptoms were given a 3-week supply of low-dose aspirin packaged in an unobtrusive electronic adherence monitor. All other medications were provided in standard pill bottles. The symptomatic patients removed their prescribed aspirin on 62.4% of the days; the patients with silent ischemia took their medication on 77.3% of the days. Possible explanations for these results, their clinical implications, and directions for future research are discussed.

Image restoration in a highly non-steady-state regime of stimulated Brillouin scattering in a photodissociation iodine laser.

For what we believe to be the first time, mask restoration in a backscattered signal in a highly non-steady-state regime of stimulated Brillouin scattering was attained. A special two-lens system of laser beam insertion into a scattering medium was used. Results are compared with those of ordinary one-lens focusing.

[Purging of hemopoietic progenitor cells in autologous transplantation]. / Cistení hemopoetických progenitorových bunek pro autologní transplantace.

The authors describe the results of purification of bone marrow and peripheral progenitor cells (PBPC) for clinical transplantations. Vepeside was used to purify in 1990-1995 a total of 41 bone marrows of adults and children. Of these 23 were transplanted. Maphosphamide was used bone marrow purging in two patients; transplantation was performed in one case. By a combination of Vepeside with methylprednisolone haematopoietic cells of 24 patients were purged, transplantations were performed in 10. Three-day cultivation of haematopoietic cells in the presence of Desferal was used for purging cells of 22 patients with neuroblastoma; transplantations were performed in 10 patients. The authors give the values of nucleated cells, haematopoietic colonies of CFU-GM and CD34 positive cells obtained after purification calculated per kg body weight of the patient and the percentage yields.

Heart rate variability is independent of age, gender, and race in congestive heart failure with a recent acute exacerbation.

Among normal adults, indexes of heart rate variability are affected by age, gender, and race. These effects are not seen among patients with congestive heart failure with a recent acute exacerbation, in whom indexes of heart rate variability are remarkably uniform and appear to be determined primarily by their recent cardiac failure.