Effect of Small Focus on Electron Heating and Proton Acceleration in Ultrarelativistic Laser-Solid Interactions.

Acceleration of particles from the interaction of ultraintense laser pulses up to 5×10^{21} W cm^{-2} with thin foils is investigated experimentally. The electron beam parameters varied with decreasing spot size, not just laser intensity, resulting in reduced temperatures and divergence. In particular, the temperature saturated due to insufficient acceleration length in the tightly focused spot. These dependencies affected the sheath-accelerated protons, which showed poorer spot-size scaling than widely used scaling laws. It is therefore shown that maximizing laser intensity by using very small foci has reducing returns for some applications.

Proton beam quality enhancement by spectral phase control of a PW-class laser system.

We report on experimental investigations of proton acceleration from solid foils irradiated with PW-class laser-pulses, where highest proton cut-off energies were achieved for temporal pulse parameters that varied significantly from those of an ideally Fourier transform limited (FTL) pulse. Controlled spectral phase modulation of the driver laser by means of an acousto-optic programmable dispersive filter enabled us to manipulate the temporal shape of the last picoseconds around the main pulse and to study the effect on proton acceleration from thin foil targets. The results show that applying positive third order dispersion values to short pulses is favourable for proton acceleration and can lead to maximum energies of 70 MeV in target normal direction at 18 J laser energy for thin plastic foils, significantly enhancing the maximum energy compared to ideally compressed FTL pulses. The paper further proves the robustness and applicability of this enhancement effect for the use of different target materials and thicknesses as well as laser energy and temporal intensity contrast settings. We demonstrate that application relevant proton beam quality was reliably achieved over many months of operation with appropriate control of spectral phase and temporal contrast conditions using a state-of-the-art high-repetition rate PW laser system.

Ion species discrimination method by linear energy transfer measurement in Fujifilm BAS-SR imaging plate.

We have developed a novel discrimination methodology to identify ions in multispecies beams with similar charge-to-mass ratios, but different atomic numbers. After an initial separation by charge-to-mass ratios using co-linear electric and magnetic fields, individual ions can be discriminated by considering the linear energy transfer of ions irradiating a stimulable phosphor plate (Fujifilm imaging plate) by comparison with the Monte Carlo calculation. We apply the method to energetic multispecies laser-driven ion beams and use it to identify silver ions produced by the interaction between a high contrast, high intensity laser pulse; and a sub-micrometer silver foil target. We also show that this method can be used to calibrate the imaging plate for arbitrary ion species in the range of Z ≥ 6 with dE/dx > 0.1 MeV/µm without requiring individual calibration.

Laser ion acceleration via control of the near-critical density target.

Duration-controlled amplified spontaneous emission with an intensity of 10(13) W/cm(2) is used to convert a 7.5-microm -thick polyimide foil into a near-critical plasma, in which the p -polarized, 45-fs , 10(19) -Wcm (2) laser pulse generates 3.8-MeV protons, emitted at some angle between the target normal and the laser propagation direction of 45 degrees . Particle-in-cell simulations reveal that the efficient proton acceleration is due to the generation of a quasistatic magnetic field on the target rear side with magnetic pressure inducing and sustaining a charge separation electrostatic field.

Scintillator-based transverse proton beam profiler for laser-plasma ion sources.

A high repetition rate scintillator-based transverse beam profile diagnostic for laser-plasma accelerated proton beams has been designed and commissioned. The proton beam profiler uses differential filtering to provide coarse energy resolution and a flexible design to allow optimisation for expected beam energy range and trade-off between spatial and energy resolution depending on the application. A plastic scintillator detector, imaged with a standard 12-bit scientific camera, allows data to be taken at a high repetition rate. An algorithm encompassing the scintillator non-linearity is described to estimate the proton spectrum at different spatial locations.

Estimation of photon dose generated by a short pulse high power laser.

The authors obtain a new equation to estimate the forward component of a photon dose generated through the interaction between a target and a short pulse high power laser. As the equation is quite simple, it is useful for calculating the photon dose. The equation shows that the photon dose is proportional to the electron temperature in the range>3 MeV and proportional to the square of the electron temperature in the range<3 MeV. The dose estimated with this method is roughly consistent with the result of Monte Carlo simulation. With some assumptions and corrections, it can reproduce experimental results obtained and the dose result calculated at other laboratories.

Nonlinear increase of X-ray intensities from thin foils irradiated with a 200 TW femtosecond laser.

We report, for the first time, that the energy of femtosecond optical laser pulses, E, with relativistic intensities I > 10(21) W/cm(2) is efficiently converted to X-ray radiation, which is emitted by "hot" electron component in collision-less processes and heats the solid density plasma periphery. As shown by direct high-resolution spectroscopic measurements X-ray radiation from plasma periphery exhibits unusual non-linear growth ~E(4-5) of its power. The non-linear power growth occurs far earlier than the known regime when the radiation reaction dominates particle motion (RDR). Nevertheless, the radiation is shown to dominate the kinetics of the plasma periphery, changing in this regime (now labeled RDKR) the physical picture of the laser plasma interaction. Although in the experiments reported here we demonstrated by observation of KK hollow ions that X-ray intensities in the keV range exceeds ~10(17) W/cm(2), there is no theoretical limit of the radiation power. Therefore, such powerful X-ray sources can produce and probe exotic material states with high densities and multiple inner-shell electron excitations even for higher Z elements. Femtosecond laser-produced plasmas may thus provide unique ultra-bright X-ray sources, for future studies of matter in extreme conditions, material science studies, and radiography of biological systems.

Correlation between metabolism of betamethasone 17,21-dipropionate and adrenal hypertrophy in rat fetuses.

The effects of metabolites of betamethasone 17,21-dipropionate (BMDP) on the hypothalamo-pituitary-adrenocortical axis were assessed by measurements of adrenal weights, after studying the metabolism of BMDP in vivo and in vitro in pregnant rats and mice. After BMDP was injected intravenously at a dose of 5 mg/kg into rats and mice in late stages of pregnancy, it disappeared rapidly from the plasma and brain stages of pregnancy, it disappeared rapidly from the plasma and brain in both mothers and fetuses while betamethasone 17-propionate (BMP) was detected as the main metabolite followed by betamethasone (BM). In vitro studies demonstrated that BMDP was metabolized to BMP in maternal and fetal tissues (plasma, liver, brain and placenta) of both species. The subcutaneous administration of BMP to rats in the late stages of pregnancy induced adrenal hypertrophy in fetuses, though the adrenals of the mothers became atrophic. In the case of mice, both maternal and fetal adrenals became atrophic. Administration of BM produced adrenal atrophy in mothers and fetuses of both species. The subcutaneous administration of 6 beta-hydroxybetamethasone 17-propionate (6 beta-OH-BMP) to rat fetuses in utero produced adrenal hypertrophy and 6 beta-hydroxybetamethasone (6 beta-OH-BM) showed no effect. These data suggest that BMP is transferred across the placental barrier to produce marked adrenal hypertrophy in rat fetuses.

Changes in serum hepatic fibrosis markers in biochemical responders to interferon therapy for chronic hepatitis C.

Serum hepatic fibrosis markers (7s domain of type IV collagen, N-terminal peptide of type III procollagen, and hyaluronate) were determined during and after a 6-month interferon treatment of patients with chronic hepatitis C. Changes in these markers were compared among the patients who showed a sustained normalization of serum alanine transaminase (ALT) levels with and without eradication of serum hepatitis C virus RNA (complete responders and biochemical responders) and nonresponders. In the case of complete responders, the serum 7s domain of type IV collagen and the N-terminal peptide of type III procollagen levels decreased at the end and 24 weeks after the end of the treatment. Hyaluronate levels were significantly decreased 24 weeks after the end of the treatment, as compared with those prior to the treatment. During and after interferon treatment, changes in these markers in the case of biochemical responders were nearly the same as those in the complete responders. These results suggest that serum hepatic fibrosis markers decrease in patients with chronic hepatitis C who show a sustained normalization of ALT after interferon treatment, even if serum hepatitis C virus RNA fails to be eradicated.

Malignant lymphoma originating in the jejunum of a long-term follow-up case of protein-losing enteropathy.

A 50-year-old female patient, who had been followed for 15 years for protein-losing enteropathy, was hospitalized due to epigastric pain. Examination on admission revealed that the patient was in the sub-ileus state. On the 26th day after admission, she complained of severe abdominal pain and shortly after she went into shock. The emergency laparotomy documented intestinal perforation and a tumor. The perforated site was right at the middle of tumor. The histological and histochemical studies identified the tumor as malignant lymphoma of B lymphocyte lineage. As far as we know, this is the third case of malignant lymphoma occurring in the jejunum in a patient with protein-losing enteropathy in Japan. The possible relationship between lymphomas and protein-losing enteropathy is discussed.

Clinical assessment of unilateral pulmonary artery occlusion test with dobutamine infusion. Expansion of surgical indications in patients with primary lung cancer and impaired cardiopulmonary functions.

OBJECTIVES: We evaluated the possibility of expanding indications for pulmonary resection based on an assessment of the pressure-flow relationship in pulmonary circulation. METHODS: In 6 of 28 lung cancer patients whose total pulmonary vascular resistance index exceeded the threshold during unilateral pulmonary artery occlusion testing, we conducted unilateral pulmonary artery occlusion testing with dobutamine administration, followed by lung resection. We studied hemodynamics during testing and derived a new indication for pulmonary resection from the postoperative course. RESULTS: Cardiac output was 3.82 +/- 0.74 l/min before testing, 3.66 +/- 0.76 l/min during pulmonary artery occlusion testing, and 5.92 +/- 1.78 l/min during unilateral pulmonary artery occlusion testing with dobutamine infusion. The total pulmonary vascular resistance index was 890 +/- 350 dyne.sec.cm-5.m2 before testing, 1170 +/- 320 dyne.sec.cm-5.m2 during testing, and 800 +/- 160 dyne.sec.cm-5.m2 during testing with dobutamine infusion. Cardiac output increased (p = 0.014) during unilateral pulmonary artery occlusion testing with dobutamine infusion, and the total pulmonary vascular resistance index significantly decreased (p = 0.034). Of the 4 patients eligible for lobectomy, 2 underwent the procedure--one undergoing segmentectomy in which pulmonary metastasis was found during surgery and the other undergoing radiotherapy for cN2 disease with chest wall invasion. Of the 2 initially ineligible for lobectomy, one underwent partial pulmonary resection and the other underwent lobectomy because the total pulmonary vascular resistance index was less than 800 dyne.sec.cm-5.m2 during selective pulmonary artery occlusion testing with dobutamine infusion, indicating eligibility for lobectomy. No severe complications of cardiopulmonary function failure after surgery occurred in any of the 5 cases. CONCLUSIONS: Unilateral pulmonary artery occlusion testing with dobutamine infusion is useful in determining patient eligibility for pulmonary resection.

[Conservative treatment of postoperative chylothorax in a patient with chronic traumatic aneurysm of thoracic aorta].

A 66-year-old male was admitted to our hospital because of a chronic traumatic aneurysm of the thoracic aorta caused by a traffic accident 5 years earlier. Although he had been treated successfully by patch closure under extracorporeal circulation, chylothorax gradually manifested 9 days after the operation. The fact that our conservative treatment resulted in complete recovery from chylothorax, strongly suggested that progress of nutriology was a contributing factor.

[A case of bilateral coronary artery fistulae into main pulmonary artery].

A case of coronary-pulmonary artery fistulae was presented with the review of the literature. A 46-year-old man was admitted to our department with an ischemic change in leads III, a VF on ECG. Although he had no complaint, the exercise ECG showed significant depression of ST segment in leads II, III, V4, V5. Coronary angiography revealed fistulae from left anterior descending branch to main pulmonary artery, and also from right coronary artery to main pulmonary artery. No coronary organic narrowing were found. Ligation of the fistulae was performed and postoperative course was uneventful.

[Total aortic arch replacement for distal aortic arch aneurysm with adhered left lung: report of a case].

A 76-year-old man with a history of pleuritis and a cerebral infarct underwent a total arch replacement for an aneurysm of the distal aortic arch. Computed tomography revealed a true aneurysm having a maximum diameter of 70 mm as well as pleural thickening and calcification. Total arch replacement with selective cerebral perfusion was performed through median sternotomy and left thoracotomy. The myocardial ischemic time was shortened by reperfusion from the right axillary artery after the anastomosis of the proximal ascending aorta and the brachiocephalic artery. After the other branches of the arch were anastomosed, a distal anastomosis through the left thoracotomy was then performed using the pull-through method, enabling minimal decortication of the adhered lung. Our surgical procedure for distal arch aneurysm with adhered lung involves the addition of a left thoracotomy, but the reduction in the myocardial ischemic time and lung injury are of benefit.

[Increased incidence of hepatocellular carcinoma in abstinent patients with alcoholic cirrhosis].

The morphological features of alcoholic liver diseases were followed up for a long period in patients who continued alcoholic intake and those in whom alcoholic intake was discontinued or reduced. In the continued alcoholic intake group, liver cirrhosis, which had not been seen at the first examination, appeared in 17 of the 25 cases, whereas in the abstinence or alcohol reduction group, only 6 of the 25 cases developed liver cirrhosis. Thus, the incidence of liver cirrhosis was evidently higher in patients who continued alcoholic intake. In the continued alcoholic intake group, 11 cases had liver cirrhosis at the first examination, with 2 of these 11 cases developing hepatoma during the follow-up period. In the abstinence or alcohol reduction group, 34 cases had liver cirrhosis at the first examination and 17 of them developed hepatoma. Thus, the incidence of hepatoma which developed from liver cirrhosis was higher in the abstinence or alcohol reduction group. Of the 38 cases who discontinued alcoholic intake, 12 developed hepatoma 4 years (on the average) after the beginning of abstinence. Of the 21 cases who reduced the amount of alcoholic intake, 5 developed hepatoma 9 years and 2 months (on the average) after reduction of alcoholic intake. Among others, patients who suddenly discontinued alcoholic intake after many years of heavy drinking tended to develop hepatoma in a relatively short time after abstinence.

[A case of pleural effusion secondary to breast carcinoma responding to treatment based upon thoracoscopic findings].

Patients with metastatic breast carcinoma often present symptomatic pleural effusions. A 67-years-old woman, who had undergone right radical mastectomy 7 years previously for right breast carcinoma, developed massive right pleural effusion. Thoracoscopy revealed local metastasis in the center of the parietal mediastinal pleura. On biopsy, it was found to be adenocarcinoma which was considered to have invaded the pleura directly from the mediastinum. She was treated with linac X-ray irradiation focused on the pleural metastasis and systemic chemotherapy (CMF), and resulted in a gradual decrease and final disappearance of the pleural effusion.

Measurements of electron-induced neutrons as a tool for determination of electron temperature of fast electrons in the task of optimization laser-produced plasma ions acceleration.

High intensity laser-plasma interaction has attracted considerable interest for a number of years. The laser-plasma interaction is accompanied by generation of various charged particle beams, such as high-energy proton and ions with high charge to mass ratio (Q/M; same as multi-charged ions). Results of simultaneous novel measurements of electron-induced photonuclear neutrons (photoneutron), which are a diagnostic of the laser-plasma interaction, are proposed to use for optimization of the laser-plasma ion generation. The proposed method is demonstrated by the laser irradiation with the intensity of 1 × 10(21) W/cm(2) on the metal foil target. The photoneutrons are measured by using NE213 liquid scintillation detectors. Heavy-ion signal is registered with the CR-39 track detector simultaneously. The measured signals of the electron-induced photoneutrons are well reproduced by using the Particle and Heavy Ion Transport code System. The results obtained provide useful approach for analyzing the various laser based ion beams.

Multi-charged heavy ion acceleration from the ultra-intense short pulse laser system interacting with the metal target.

Experimental demonstration of multi-charged heavy ion acceleration from the interaction between the ultra-intense short pulse laser system and the metal target is presented. Al ions are accelerated up to 12 MeV/u (324 MeV total energy). To our knowledge, this is far the highest energy ever reported for the case of acceleration of the heavy ions produced by the <10 J laser energy of 200 TW class Ti:sapphire laser system. Adding to that, thanks to the extraordinary high intensity laser field of ∼10(21) W cm(-2), the accelerated ions are almost fully stripped, having high charge to mass ratio (Q/M).

Development of a single-shot-imaging thin film for an online Thomson parabola spectrometer.

A single-shot-imaging thin scintillator film was developed for an online Thomson parabola (TP) spectrometer and the first analysis of laser accelerated ions, using the online TP spectrometer, was demonstrated at the JAEA-Kansai Advanced Relativistic Engineering Laser System (J-KAREN). An energy spectrum of ~4.0 MeV protons is obtained using only this imaging film without the need of a microchannel plate that is typically utilized in online ion analyses. A general-purpose Monte Carlo particle and heavy ion-transport code system, which consists of various quantum dynamics models, was used for the prediction of the luminescent properties of the scintillator. The simulation can reasonably predict not only the ion trajectories detected by the spectrometer, but also luminescence properties.