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Second harmonic generation (SHG) is a phenomenon observed in nonlinear optics that leads to frequency duplication for a high intensity laser incident on nonlinear crystal using BBO crystal. The SHG yield is achieved when the photons interact with a nonlinear optical material and effectively combine to form new photons with double frequency, and therefore double energy and half wavelength. This paper is concerned with the establishment of an SHG experiment to govern the process of producing half-wavelength laser beam from the input one. The theoretical effort was extended to compute the efficiency by using MATLAB software based on mathematical relationships. The values of the conversion maximum efficiencies, which were computed as a function of the input and output powers of the theoretical computations, were 15.6% and 16% at input and output power values of 0.6 and 0.1, respectively. The experimental results of the laser source of 532nm wavelength (fundamental frequency was 0.563x1015s-1) gave a half wavelength of 266nm (double frequency was 1.126x1015s-1). The conversion efficiencies, computed as a function of the input and output powers of the experimental measurements, were 14.32% and 12.97%, respectively. [ABSTRACT FROM AUTHOR]

It is well known that the laser--target interaction at high power and high laser intensity may result in the emission of strong electromagnetic pulses with frequencies in the range from tens of MHz to a few GHz and the duration of hundreds of nanoseconds. It was recently pointed out that the electric polarization of the target and the resulting neutralization current play an important role in the electromagnetic pulses emission. The target charge and the neutralization current generated with laser pulses of 30 fs to several ps duration were studied in detail at the Eclipse laser facility at CELIA, Bordeaux, with the laser pulse energy at the level of up to 100 mJ on target. In this contribution we report on the measurements of the target charge and the electromagnetic pulses performed at the 10 TW fs laser facility in IPPLM, Warsaw, for the laser pulse energies reaching 400 mJ on target and the laser pulse duration in the range of 50 fs to 400 fs. Due to higher laser pulse energy, the effect of proton acceleration off the rear side of the thin foil targets could be easily observed. This is an important bonus since the mechanism of target normal sheath acceleration of protons which prevails in these laser conditions is closely related to the mechanism of charge ejection from the target, thus providing an additional constraint on any attempts at modeling of the target charge. The collected data is confronted with simplified models of charge ejection and target normal sheath acceleration of protons and qualitative agreement is found. [ABSTRACT FROM AUTHOR]

Over the past decade, High Intensity Focused Ultrasound (HIFU) has emerged as an important novel therapeutic modality in the treatment of cancers, that avoids many of the associated negative side effects of more well-established cancer therapies (eg chemotherapy and radiotherapy). In this paper, a coupled system of partial differential equations is used to model the interaction of HIFU with biological tissue. The mathematical model takes into account the effects of both diffusive and convective transport on the temperature field, when acoustic (ultrasound) energy is deposited at a particular location (focal point) in the biological tissue. The model poses significant challenges in establishing existence and uniqueness of solutions, which we consider to be a crucial first step in any realistic, applied mathematical study of HIFU therapy. In this paper, we establish well-posedness of our model, using the Leray-Schauder principle, together with a-priori estimates. [ABSTRACT FROM AUTHOR]

We consider a quantum mechanical model for the high-order harmonic generation in bulk solids. The bandgap is assumed to be considerably larger than the exciting photon energy. Using dipole approximation, the dynamical equations for different initial Bloch states are decoupled in the velocity gauge. Although there is no quantum mechanical interference between the time evolution of different initial states, the complete harmonic radiation results from the interference of fields emitted by all the initial (valence band) states. In particular, the suppression of the even-order harmonics can also be viewed as a consequence of this interference. The number of the observable harmonics (essentially the cutoff) is also determined by interference phenomena. [ABSTRACT FROM AUTHOR]

We demonstrate the use of a 3D printed radial collimator in X-ray powder diffraction and surface sensitive grazing incidence X-ray diffraction. We find a significant improvement in the overall signal to background ratio of up to 100 and a suppression of more than a factor 3 · 105 for undesirable Bragg reflections generated by the X-ray "transparent" windows of the sample environment. The background reduction and the removal of the high intensity signals from the windows, which limit the detector's dynamic range, enable significantly higher sensitivity in experiments within sample environments such as vacuum chambers and gas- or liquid-cells. Details of the additively manufactured steel collimator geometry, alignment strategies using X-ray fluorescence, and data analysis are also briefly discussed. The flexibility and affordability of 3D prints enable designs optimized for specific detectors and sample environments, without compromising the degrees of freedom of the diffractometer. [ABSTRACT FROM AUTHOR]

Abstract Multi MeV protons (Snavely et al., 2000) and heavier ions are emitted by thin foils irradiated by high-intensity lasers, due to the huge accelerating fields, up to several teraelectronvolt per meter, at sub-picosecond timescale (Dubois et al., 2014). The evolution of these huge fields is not well understood till today. Here we report, for the first time, direct and temporally resolved measurements of the electric fields produced by the interaction of a short-pulse high-intensity laser with solid targets. The results, obtained with a sub-100 fs temporal diagnostics, show that such fields build-up in few hundreds of femtoseconds and lasts after several picoseconds. [ABSTRACT FROM AUTHOR]

Abstract To this day the interaction of high-intensity lasers with matter is considered to be a possible candidate for next generation particle accelerators. Within the LIGHT collaboration crucial work for the merging of a high-intensity laser driven ion source with conventional accelerator technology has been done in the past years. The simulation studies we report about are an important step in providing short and intense mid-Z heavy ion beams for future applications. Highlights • Coupling of laser-driven ion beams into conventional accelerators is quintessential. • Transport efficiency of 20% for carbon ions at 1 MeV/u over 6 m in simulations. • Simulations showcase intense beams with up to 1 0 8 carbon ions in t p u l s e < 0. 5 ns. [ABSTRACT FROM AUTHOR]

In this paper, a mathematical physics model is set up to study dielectric constant profile of aqueous solvent in ionic solution, to revise Brownian dynamics simulation in ionic solution by considering time-variant dielectric constant profile with change in ion positions, and to study the effect of high-intensity electric pulses on the profile. The validation of the model is confirmed with verification calculations. By means of the proposed model, dielectric constant profiles in calcium chloride and sodium chloride solutions and their response to pulses are simulated. Based on numerical results, dielectric constants of aqueous solvent spatially vary instead of being the same value in ionic solutions. And the profiles are variant with time due to ion motion in solutions. From the profiles, overall dielectric constant in calcium chloride solution is lower than that in sodium chloride solution. And overall dielectric constant decreases with increment of solution concentration. In addition, the results show that influence on the profiles depends on solution concentration and field intensity of the pulse. The profile in solutions with low concentration is more vulnerable to the pulse than that with high concentration. And overall dielectric constant decreases dramatically as field intensity increases. Those understandings provide basis for application of pulses in biomedical engineering at the molecular level. Meanwhile, pulse radiation provides a potential way to constrain water molecules at room temperature reflected by significantly reducing dielectric constant, and to lower absorption loss of electromagnetic field in millimeter and far infrared band. [ABSTRACT FROM AUTHOR]

Abstract The aim of this research is to develop a new method for the enhancement of bioactivity of glass and transparent materials by the deposition of Ti nanofibrous structures generated by a high intensity laser induced reverse transfer method (HILIRT). Titanium nanofibers with different porosity, fiber diameter, and bioactivity are synthesized at various ranges of pulse frequency, power, and scanning speed combined with the HILIRT method. Features and bioactivity of these deposited Ti coatings before and after seven days immersion in simulated body fluid are compared. The results show increasing laser frequency and laser power leads to more Ti nanofiber generation and enhanced biocompatibility, while increasing laser scanning speed results in lower Ti nanofiber growth and lower biocompatibility. Combination of the laser parameters such as frequency, power, and scanning speed can optimize the deposited Ti nanofiber properties for a wide range of biomedical applications using transparent biomaterials such as implanted optoelectronics and light guiding devices, lab on a chip (LoC) and in-vitro and real time analysis of living cells in laboratories. Highlights • New method for generation of nanofibrous thin-film biocompatible materials via laser pulses and under ambient conditions. • Enhancement of biocompatibility of bioglass and transparent materials in single step. • Introduction of new concept for deposition of nanofibers on transparent materials. • Study the effect of laser pulses on the biocompatibility of the synthesized nanofibrous structures on the glass substrate. [ABSTRACT FROM AUTHOR]

Objective: The purpose of this study was to assess the effectiveness of pulsed high-intensity laser therapy on pain, adhesions, and quality of life in women with endometriosis. Background data: Endometriosis is among the most common gynecological problems affecting females of childbearing age. The majority of women with endometriosis seek treatment to alleviate pain. Materials and methods: The sample included 40 women with endometriosis to either a mild or a moderate degree aged between 24 and 32 years. They were randomly assigned to two groups, group I of 20 women received pulsed high-intensity laser therapy three times per week for 8 weeks, as well as the usual regimen of hormonal treatment given to endometriosis patients, and group II of 20 women were given sham laser treatment three times per week for 8 weeks and the usual regimen of hormonal treatment. For all patients, pain, the degree of endometriosis, and quality of life were measured using present pain intensity and pain relief scales, laparoscopy, and the Endometriosis Health Profile (EHP-5) before treatment began and at the end of the 8 weeks. Results: In comparison to the sham laser treatment, pulsed high-intensity laser therapy produced a significantly different result ( p < 0.0001), in women with endometriosis. Conclusions: Pulsed high-intensity laser therapy is an effective method of pain alleviation, reducing adhesions, and improving the quality of life in women with endometriosis. [ABSTRACT FROM AUTHOR]

Objective: The aim of this study was to evaluate the efficacy of high-intensity laser therapy (HILT) in the treatment of knee osteoarthritis (OA). Background: Due to increased number of randomized controlled trials evaluating efficiency of HILT in patients with knee OA, there was a need to present them in the form of systematic review. Methods: The search includes the databases as well as a manual search until August, 2017. The quality of the selected articles was determined in accordance with the revised guidelines of the CONSORT statement. Results: Six studies were included. Laser fluence ranged from 0.51 to 120 J/cm2 for one treatment. The total energy transmitted during one treatment ranged from 1250 to 3000 J. All the selected studies found HILT to be beneficial in treatment of knee OA. Conclusions: HILT seems to be efficient in reducing pain and for providing functional improvements in patients with knee OA. [ABSTRACT FROM AUTHOR]

The recent development of ultra-high intensity laser facilities is finally opening up the possibility of studying high-field quantum electrodynamics in the laboratory. Arguably, one of the central phenomena in this area is that of quantum radiation reaction experienced by an ultra-relativistic electron beam as it propagates through the tight focus of a laser beam. In this paper, we discuss the major experimental challenges that are to be faced in order to extract meaningful and quantitative information from this class of experiments using existing and near-term laser facilities. [ABSTRACT FROM AUTHOR]

Background and aims High-intensity interval training (HIIT) has been identified to be efficient for increasing health-related fitness in general and in lifestyle-induced chronic diseases such as hypertension, obesity and metabolic syndrome. This study aimed to evaluate HIIT effects on optic nerve head (ONH) and macular perfusion in healthy adults using optical coherence tomography angiography (OCTA). Methods Fifty-eight healthy participants (22.0 ± 2.02 years, 40 females (69.0%)) performed a 4-week HIIT with two exercise sessions/week: Group 1, 4 × 30 HIIT, running at maximal speed (all-out) for 4 × 30 s with 30 s active recovery, Group 2, 8 × 15 HIIT, running at maximal speed (all-out) for 8 × 15 s with 15 s active recovery. OCTA of the ONH and the macula was performed at baseline and follow-up to detect changes of the foveal avascular zone (FAZ). Flow density was evaluated in the superficial and deep plexus of the central macula, in the radial peripapillary capillary layer, the nerve head layer of the disc region and of the peripapillary region. Results The mean deep FAZ area and flow density of the superficial layer decreased by 14.00 ± 13.02% and 1.26 ± 3.20%, respectively, in response to overall HIIT (pre vs . post p <0.0001; p = 0.0041). The flow density of the nerve head layer in the peripapillary area showed an overall increase by 1.94 ± 2.39% (pre vs post p  < 0.0001). All other parameters showed no difference. Conclusions HIIT may be performed to induce changes in ophthalmic measures such as FAZ and nerve head perfusion. OCTA imaging of the central retina and the ONH could represent a sensitive tool for the early detection of systemic vascular changes. [ABSTRACT FROM AUTHOR]

This study aimed to compare the effect of high-intensity interval training (HIIT) with additional whole-body vibration (WBV) on body composition and lipid profile in obese/overweight adults on a hypocaloric diet. Forty adults were randomly assigned to (a) HIIT and vibration and hypocaloric diet (HIITWBV, n ¼ 13), (b) HIIT and diet (HIIT, n ¼ 14), and (c) diet only (control [CON], n ¼ 13). High-intensity interval training WBV participants trained 3 times per week for 8 weeks (6 sets × 1 minute of HIIT, cycling at 90% heart rate peak followed by 1 minute of interset vibration, at a frequency of 18 Hz increasing until 25 Hz with a peak-topeak displacement of 4 mm. Training volume increased 1 set every 2 weeks until 10 sets). The HIIT group performed HIIT training followed by 2 minutes of passive recovery, while the CON continued with their daily activities combined with calorie restriction. Body composition (body fat and fat-free mass) and biochemical indices (glucose, total cholesterol, high-density lipoprotein cholesterol, and triglycerides) were determined. Following 8 weeks, body fat was significantly reduced by 7.5% and both triglycerides and total cholesterol decreased in the HIITWBV group only (-16.5% and -11.7% respectively). This study suggests that HIIT in combination with WBV and a hypocaloric diet can improve overall lipid profile in overweight/obese individuals. [ABSTRACT FROM AUTHOR]

Investigations of energy transfer of high intensity (I = 5 × 1019 W/cm2), ultrashort (<30 fs) Ti:Sa laser pulses to solid targets with a randomly rough surface have been performed. We investigated the influence of the target surface morphology on the efficiency of energy transfer of p- polarized laser pulses characterized by a very high contrast. Targets with a roughness σ larger than ∼20% of the laser wavelength proved to absorb a remarkably large fraction of energy reaching up to 70%, almost independent of the incidence angle. Numerical simulations of various interaction conditions are in agreement with the experimental data and confirm the effect of the target morphology and its surface parameters on the enhanced energy absorbed fraction. [ABSTRACT FROM AUTHOR]

The development, performance, and testing of the longitudinal bunch shape monitor, namely, the Fast Faraday Cup (FFC), are presented in this paper. The FFC is an invasive instrument controlled by a stepper motor, and its principle of operation is based on a strip line structure. The longitudinal bunch shape was determined by sampling a small part of the beam hitting the strip line through a 1-mm hole. The rise time of the detector reached 24 ps. To accommodate experiments that utilize high-intensity beams, the materials of the bunch shape monitor were chosen to sustain high temperatures. Water cooling was also integrated in the detector system to enhance heat transfer and prevent thermal damage. We also present an analysis of the heating caused by the beam. The bunch shape monitor has been installed and commissioned at the China ADS proton LINAC Injector II. [ABSTRACT FROM AUTHOR]

During the interaction of a short-pulse high-intensity laser with the preplasma produced by the pulse's pedestal in front of a high-Z metal solid target, high-energy electrons are produced, which in turn create an X-ray source by interacting with the atoms of the converter target. The current brought by the hot electrons is almost completely neutralized by a return current j → driven by the background electrons of the conductive target, and the force exerted on the hot electrons by the electric field E → which induces Ohmic heating j →. E → , produced by the background electrons, reduces the energy of the hot electrons and thus lowers the X-ray emission and photon dose. This effect is analyzed here by means of a simple 1-D temperature model which contains the most significant terms of the relativistic Fokker-Planck equation with electron multiple scattering, and the energy equations of ions, hot, and cold electrons are then solved numerically. This Ohmic heating energy loss fraction τOh is introduced as a corrective term in an improved photon dose model. For instance, for a ps laser pulse with 10 μm spot size, the dose obtained with a tantalum target is reduced by less than about 10% to 40% by the Ohmic heating, depending upon the plasma scale length, target thickness, laser parameters, and in particular its spot size. The laser and plasma parameters may be optimized to limit the effect of Ohmic heating, for instance at a small plasma scale length or small laser spot size. Conversely, others regimes not suitable for dose production are identified. For instance, the resistive heating is enhanced in a foam target or at a long plasma scale length and high laser spot size and intensity, as the mean emission angle θ0 of the incident hot electron bunch given by the ponderomotive force is small; thus, the dose produced by a laser interacting in a gas jet may be inhibited under these circumstances. The resistive heating may also be maximized in order to reduce the X-ray emission to lower the radiation level for instance in a safety radiological goal. [ABSTRACT FROM AUTHOR]

The recent development of ultra-high intensity laser facilities is finally opening up the possibility of studying high-field quantum electrodynamics in the laboratory. Arguably, one of the central phenomena in this area is that of quantum radiation reaction experienced by an ultra-relativistic electron beam as it propagates through the tight focus of a laser beam. In this paper, we discuss the major experimental challenges that are to be faced in order to extract meaningful and quantitative information from this class of experiments using existing and near-term laser facilities. [ABSTRACT FROM PUBLISHER]

We consider a quantum mechanical model for the high-order harmonic generation in bulk solids. The bandgap is assumed to be considerably larger than the exciting photon energy. Using dipole approximation, the dynamical equations for different initial Bloch states are decoupled in the velocity gauge. Although there is no quantum mechanical interference between the time evolution of different initial states, the complete harmonic radiation results from the interference of fields emitted by all the initial (valence band) states. In particular, the suppression of the even-order harmonics can also be viewed as a consequence of this interference. The number of the observable harmonics (essentially the cutoff) is also determined by interference phenomena.

High intensity lasers can induce in solid targets a charge separation resulting in a time-dependent induced polarization. In this work, the characterization of a plastic target subjected to a laser irradiation has been analysed. A focus was particularly devoted to the interaction of the target with the whole grounded chamber, manipulated through the change of the target-holder surface ratio. The targets are thick samples (thickness >1 mm) of polymers arranged in discs according to the metallic holder shape. A possible correlation between the target current and the main features of the produced plasma was analyzed, in order to acquire a deeper knowledge on laser–matter interactions with the laser pulse on the nanosecond scale. Collected signals were analyzed to reconstruct the time evolution of key observables as well as the charge space distribution in the chamber. The experimental setting allowing the target current observation and the measurement procedure is discussed. [ABSTRACT FROM AUTHOR]

We present an improvement design of a two-dimensional (2D) angular-resolved proton spectrometer for wide-angle measurement of proton beams from high-intensity laser-solid interactions. By using a 2D selective entrance pinhole array with different periods in orthogonal axes, the angular resolution along one dimension is improved by a factor of 6.7. This improvement provides the accessibility to detect the spatial fine structures of the proton energy spectrum. [ABSTRACT FROM AUTHOR]

The results of investigating the focusing of a high-power ion beam, which is formed by a diode with a semicylindrical geometry and a passive anode, are presented. Two types of focusing diodes were investigated: with external magnetic insulation (one-pulse mode) and self-magnetic insulation of electrons (twopulse mode). Measurements of the energy-density distribution of the ion beam and the ion-current density were performed. It was found that when the diode operates in the two-pulse mode, the region of the maximum ion-beam energy density in the focal plane is displaced relative to the region of the maximum ion-current density by 5-10 mm. It is shown that the effect of a displacement of the focal spot with the maximum energy density is determined by the presence of a large number of accelerated neutral atoms in the ion beam. These atoms are produced as a result of the ion charge-exchange process in the anode-cathode gap of the ion diode during its operation in the two-pulse mode. [ABSTRACT FROM AUTHOR]

For the 4r=360° space-charge resonance in high intensity linear accelerators, the emittance growth is surveyed for input Gaussian beams, as a function of the depressed phase advance per cellrand the initial tune depression (r∘ -r). For each data point, the linac lattice is designed such that the fourth order resonance dominates over the envelope instability. The data show that the maximum emittance growth takes place at r≈ 87∘ over a wide range of the tune depression (or beam current), which confirms that the relevant parameter for the emittance growth is r and that for the bandwidth is r∘ - r. An interesting four-fold phase space structure is observed that cannot be explained with the fourth order resonance terms alone. Analysis attributes this effect to a small negative sixth order detuning term as the beam is redistributed by the resonance. Analytical studies show that the tune increases monotonically for the Gaussian beam which prevents the resonance for r>90°. Frequency analysis indicates that the four-fold structure observed for input Kapchinskij-Vladmirskij beams when r<90°, is not the fourth order resonance but a fourth order envelope instability because the 1/4=90°/360° component is missing in the frequency spectrum. [ABSTRACT FROM AUTHOR]

We assessed the long-term effects of pulsed high-intensity laser therapy (HILT) in post-burn pruritus treatment. A total of 49 adult burn patients with mean age of 31.53 ± 10.14 years participated, with 24 patients randomly assigned to the active laser group (ALG) and 25 in the placebo laser group (PLG). The ALG received HILT three times per week for 6 weeks, while the PLG received placebo HILT. Both groups received 10-mg cetirizine tablets twice daily and 10 mg at bedtime. All patients were advised to massage their burn scars with coconut oil for 5 min four times daily. The outcomes measured were the itch severity scale (ISS), impairment of pruritus-related quality of life (QoL), pain level by the visual analog scale (VAS), hand grip strength by handheld dynamometer, and daily cetirizine intake. Repeated-measures ANOVA was used to compare the baseline and post-treatment measurements and after 12 weeks of follow-up. Statistical significance was set at P < 0.05. ISS decreased significantly in the ALG after 6 weeks of treatment and after 12 weeks of follow-up compared with the PLG. The QoL results showed a significant improvement in the ALG compared with the PLG, which continued after 12 weeks. VAS results significantly decrease, hand grip strength significantly improved, and cetirizine intake significantly decreased post-treatment in the ALG relative to the PLG. HILT combined with cetirizine seems more effective in patients with post-burn pruritus than a placebo laser procedure with cetirizine. [ABSTRACT FROM AUTHOR]

Purpose A major complication for abdominal High Intensity Focused Ultrasound ( HIFU) applications is the obstruction of the acoustic beam path by the thoracic cage, which absorbs and reflects the ultrasonic energy leading to undesired overheating of healthy tissues in the pre-focal area. Prior work has investigated the determination of optimized transducer apodization laws, which allow for a reduced rib exposure whilst (partially) restoring focal point intensity through power compensation. Although such methods provide an excellent means of reducing rib exposure, they generally increase the local energy density in the pre-focal area, which similarly can lead to undesired overheating. Therefore, this numerical study aimed at evaluating whether a novel transducer design could provide improvement for intercostal HIFU applications, in particular with respect to the pre-focal area. Methods A combination of acoustic and thermal simulations was used to evaluate 2 mono-element transducers, 2 clinical phased array transducers, and 4 novel transducers based on Fermat's Spiral ( FS), two of which were Voronoi-tessellated ( VTFS). Binary apodizations were determined for the phased array transducers using a collision detection algorithm. A tissue geometry was modeled to represent an intercostal HIFU sonication in the liver at 30 and 50 mm behind the ribs, including subsequent layers of gel pad, skin, subcutaneous fat, muscle, and liver tissue. Acoustic simulations were then conducted using propagation of the angular spectrum of plane waves ( ASPW). The results of these simulations were used to evaluate pre-focal intensity levels. Subsequently, a finite difference scheme based on the Pennes bioheat equation was used for thermal simulations. The results of these simulations were used to calculate both the energy density in the pre-focal skin, fat, and muscle layers, as well as the energy exposure of the ribs. Results The acoustic simulations showed that for a sonication in a single point without beamsteering, comparing the best performing clinical phased array in this study to an equivalent VTFS transducer, the maximum intensity in the focal point was increased from 19.0 to 27.0 W/mm2 for the sonication 30 mm behind the ribs, while the rib area exposed to ≥20 J/cm2 was reduced from 0.88 to 0.14 cm2. For the sonication 50 mm behind the ribs, the maximum focal point intensity was increased from 13.4 to 21.5 W/mm2, while the rib area exposed to ≥40 J/cm2 was lowered from 2.71 to 0.01 cm2. The thermal simulations showed that for a circular sonication cell of 4 mm diameter in the transversal plane, sonication times for sonications 30/50 mm behind the ribs were reduced from 13.9 to 8.38 s/38.2 to 17.4 s, respectively. Energy density levels in the skin for these sonications were decreased from 5.28 to 2.22/9.45 to 3.78 J/mm2. Conclusions VTFS transducers are expected to provide improvement for intercostal HIFU applications compared to currently available clinical transducers, as they reduce both the energy density in the pre-focal zone and the energy exposure of the ribs. These characteristics allow for increasing either the re-sonication rate or the treatment volume per sonication. [ABSTRACT FROM AUTHOR]

Laser biostimulation involves applying a laser beam to the tissue to facilitate healing and regenerative processes. Laser therapy is one of the most important physical methods used in human physiotherapy. In veterinary medicine, laser therapy is a new and so far poorly examined method. The results of studies conducted so far are very promising, yet the positive effect of laser light, especially that of class IV, has yet to be confirmed. This article presents an overview of the available literature on the effect of laser treatment on the human and animal organism. [ABSTRACT FROM AUTHOR]

High intensity ultrasound (HIUS) is a novel and efficient tool for top-down nanostructuring of multi-phase metal systems. Ultrasound-assisted structuring of the phase in metal alloys relies on two main mechanisms including interfacial red/ox reactions and temperature driven solid state phase transformations which affect surface composition and morphology of metals. Physical and chemical properties of sonication medium strongly affects the structuring pathways as well as morphology and composition of catalysts. HIUS can serve as a simple, fast, and effective approach for the tuning of structure and surface properties of metal particles, opening the new perspectives in design of robust and efficient catalysts. [ABSTRACT FROM AUTHOR]

With the advent of ultrashort high intensity laser pulses, laser absorption during laser-plasma interactions has received significant attention during the past two decades since it is related to a variety of applications of high intensity lasers, including the hot electron production for fast ignition of fusion targets, bright X-ray and gamma-ray sources, ion acceleration, compact neutron sources, and generally the creation of high energy density matters. Although some absorption mechanisms appear for short laser pulses with nanosecond duration time, they usually appear for some nonlinear phenomena as electron ohmic heating and laser pulse ponderomotive force are not considered. In this paper, the absorption of the S-polarized laser pulse through an interaction with an underdense plasma in attendance of electron ohmic heating and ponderomotive nonlinearities is analyzed. It is shown that, due to the effect of the ponderomotive force in both isothermal and non-isothermal plasmas, the increasing laser radiation angle leads to the increasing electric field wavelength. Also, since the ponderomotive force modifies the electron density and temperature distribution, it is shown that the decreasing radiation angle leads to the steepening of the electron density profile and the narrowing of electron bunching. Furthermore, by increasing the radiation angle, the absorption coefficient is decreased strongly. It is found that due to the heat of the plasma at the expanse of the wave energy in the case of a non-thermal plasma, the absorption coefficient is increased intensively in comparison to a collisional plasma. [ABSTRACT FROM AUTHOR]

Background Routine diagnostic Transcranial Magnetic Stimulation (TMS) is performed with a round coil (RC) for cranial and spinal root stimulation, being less successful for motor evoked potentials (MEP) of lower limb muscles. MEP elicited with a special configured flat figure-of-eight coil designed for high intensity stimulation (HI-coil) were compared to RC with regard to handling, efficiency, and physiological properties of MEP. New methods MEP elicited with HI-coil and 9-cm diameter RC for cortical, spinal and peripheral stimulation (PES) were compared for Motor threshold (MT), latencies and amplitudes of bilateral Abductor pollicis brevis (APB) and Abductor hallucis muscles (AH). Results and comparison with existing methods MT for HI-coil were significantly lower for cortical and spinal root stimulation compared to RC (APB: 37% vs. 48%; AH: 58% vs. 72%). MEP-latencies elicited with HI-coil and RC were without significant difference. AH-MEP amplitudes were significantly larger for HI-coil cortical (705 ± 980 μV vs. 370 ± 280 μV) and root stimulation (260 ± 210 μV vs. 151 ± 100 μV). Amplitudes elicited by PES compared to HI-coil were always significantly larger. Conclusion Results for cortical and spinal root stimulation with regards to latencies and amplitudes for APB were equivalent between HI-coil and RC. PES was superior in achieving supramaximal stimulation in terms of amplitudes. The use of the HI-coil might be advantageous for MEP of lower extremity muscles with emphasis on pathologic conditions requiring higher stimulation intensities. [ABSTRACT FROM AUTHOR]

The commissioning of up-to-date linacs, designed to deliver flattening-filter-free (FFF) photon beams, is performed by measurements using air-vented ionization chambers which are often employed for traditional beams. The aim is to select the ionization chambers which are able to minimize the ion recombination effect, critical for these high intensity beams. In order to provide operators with information about the response to FFF beams of widely used chambers, the recombination correction factor k s and the dose-per-pulse (DPP) were determined in different irradiation conditions. The study, performed by using devices available in most radiotherapy departments, confirmed the reliability of the Boag model for FFF beams as well as with-flattening-filter (WFF) beams. The results showed that k s factor largely depends on the spacing between the collecting electrodes ( d el )in the ionization chamber and on the DPP of the linac output, which in turn depends on beam energy but is independent of monitor unit rate (MU/min). For plane-parallel and pin-point chambers, whose d el is minimal, the k s factor is negligible, whereas for Farmer type chambers the recombination could be important and hence the correction is to be applied (also at voltages higher than the recommended one). [ABSTRACT FROM AUTHOR]

High intensity focused ultrasound (HIFU) has recently emerged as a promising alternative approach for thrombolysis. However, the high acoustic energy required by HIFU could elicit thermal damage bioeffects, impeding the clinical translation of this technique. This paper investigates the use of dual-frequency focused ultrasound (DFFU) mediated by microbubbles (MBs) to minimize the acoustic power required for thrombolysis in vitro. It was found that MBs, with sufficient concentration, could significantly lower the power threshold for thrombolysis for both DFFU and single-frequency focused ultrasound (SFFU). In addition, SFFU needs about 96%-156% higher energy to achieve the same thrombolysis efficiency as that of DFFU. The thrombolysis efficiency is also found to increase with the duty cycle. The measured cavitation signals reveal that the enhanced inertial cavitation is likely responsible for the improved thrombolysis under DFFU and MBs. [ABSTRACT FROM AUTHOR]

High-intensity lasers interacting with solids in vacuum produce non-equilibrium plasma having high equivalent temperatures and high ion energies. In these conditions, depending on the laser parameters, irradiation conditions and target composition and geometry, different nuclear reactions can be induced due to both the high plasma temperature and the wide ion energy distribution of the accelerated species. By focusing the laser spot of very high laser intensities above 1015 W/cm2on solid targets it is possible to accelerate electrons and ions at relativistic energies above 1–10 MeV/nucleon, sufficient to penetrate into the nucleus of many light atoms. Thus laser–plasma may induce activation, transmutation, fission and fusion processes. The high plasma density and the non-isotropic plasma distribution enhance the number of nuclear events during the laser–plasma interaction along special directions. X and gamma rays, electrons, different ion species and neutrons can be produced mono-energetically or in wide energy distribution. The nuclear reactions2H(d,n)3He,2H(d,p)3H,7Li(d,n)8Be and11B(p,a)8Be are discussed in more detail with respect to many others when hydrogenated targets containing deuterium, lithium and boron are employed, respectively. The monitoring of the plasma pulse and of the products of the nuclear reactions using different detectors and techniques are also presented and discussed. [ABSTRACT FROM PUBLISHER]

The objective of this study was to induce crystallization in enzymatically interesterified fats (IE) with 20 and 30% palmitic acid at the sn-2 position using high intensity ultrasound (HIU). The physical blends (PB) used to prepare these two IE were consisted of tripalmitin and high oleic sunflower oil and contained 13.2 and 27.1% tripalmitin, respectively. Crystallization behavior of IE was compared with PB at supercoolings of 9, 6 and 3 °C. Results show that the melting point, SFC, and crystallization rate of PB were higher than IE and were driven mainly by tripalmitin content. HIU induced crystallization and generated small crystals in the IE samples. At 9 °C supercooling, sonication did not increase the viscosity of IE C16:0 20%, while that of the IE C16:0 30% increased significantly from 192.4 ± 118.9 to 3297.7 ± 1368.6 Pa·s. The elastic modulus (G') for IE C16:0 30% increased from 12521 ± 2739.8 to 75076.7 ± 18259 Pa upon sonication at 9 °C supercooling, while the G' of the IE C16:0 20% did not increase. Similar behavior was observed for the other supercoolings tested. This research suggests that HIU can improve the functional properties of IE with low content of C16:0 creating more viscous and elastic materials. These fats with low C16:0 content and improved functional properties could be used as trans-free fat alternatives. [ABSTRACT FROM AUTHOR]

We have developed a cryogenic target for use at the High Intensity γ -ray Source (HI γ S). The target system is able to liquefy 4 He at 4 K, hydrogen at 20 K, and deuterium at 23 K to fill a 0.3 L Kapton cell. Liquid temperatures and condenser pressures are recorded throughout each run in order to ensure that the target's areal density is known to ∼ 1 %. The target is being utilized in a series of experiments which probe the electromagnetic polarizabilities of the nucleon. [ABSTRACT FROM AUTHOR]

The effective scaling of positron-electron pair production by direct, ultraintense laser-matter interaction is investigated for a range of target materials and thicknesses. An axial magnetic field, acting as a focusing lens, was employed to measure positron signals for targets with atomic numbers as low as copper (Z=29). The pair production yield was found to be consistent with the Bethe-Heitler mechanism, where the number of positrons emitted into a 1 steradian cone angle from the target rear was found to be proportional to Z2. The unexpectedly low scaling results from Coulomb collisions that act to stop or scatter positrons into high angles. Monte Carlo simulations support the experimental results, providing a comprehensive power-law scaling relationship for all elemental materials and densities. [ABSTRACT FROM AUTHOR]

SiC detectors for charged particle identification can be assembled as a “telescope” device. It represents a powerful detector showing some advantages with respect to the traditional silicon ones. Their high gap energy, high density, high sensitivity, and high radiation resistance confer indisputable advantages with respect to silicon. A special geometry for this telescope is proposed and discussed in order to detect ions from low kiloelectron-volts energy up to energies of 100 MeV using different fluence. An active depth of 100~\mu \textm is employed for the ion stopper detector and an active superficial layer of 4- \mu \textm depth for the energy loss detector. Applications to low fluence use radioactive sources, while short plasma pulses generated by high intensity lasers are used at high fluence. [ABSTRACT FROM AUTHOR]

Objective: The purpose of the present study was investigation of eight weeks high intensity interval (HIIT) along with curcumin supplementation on liver Glutathione Peroxidase (GPX) Activity & Malondialdehyde (MDA) Concentration among diabetic male rats. Materials and Methods: Thirty-two male mice were divided to four groups of control-diabetic, exercise-diabetic, supplementarydiabetic, and exercise-supplementary-diabetic. Eight weeks' aerobic training schedule was five weekly sessions for the two exercise groups, which each session executed on animal treadmill with speed of 24 (m/min), steep of 0°, and entire span of 18 min. The two supplementary groups were being fed daily amount of 50 (mg/kg) curcumin supplementary, by using the gavage technique. The rats were killed and liver tissues were separated, after the eight weeks' schedule. Thereafter, in order to study variations of GPX and MDA enzymes, Kits of Zelbio Co. were implemented. Results: Activity levels of GPX enzyme and MDA concentration of the three groups of exercise-diabetic, supplementary-diabetic, and exercise-supplementary-diabetic in order increased and decreased than those of the control-diabetic one, significantly (P≤0.05). Discussion: both exercise and curcumin can be recommended as effective interventions on improvement of Glutathione Peroxidase (GPX) Activity & Malondialdehyde (MDA) Concentration of the liver, in diabetic condition. [ABSTRACT FROM AUTHOR]

In this study, we investigated the ripple patterns formation on the surface of Zr 41.2 Ti 13.8 Cu 12.5 Ni 10 Be 22.5 (vit1) bulk metallic glass using a nanosecond pulse laser ablation in air with a wavelength of 1064 nm. The strong thermal ablation phenomenon could be observed on vit1 BMG surface at laser energy of 200 mJ as a result of the adhibition of confining overlay. Many periodic ripples had formed on the edge of the ablated area at laser energy of 400 mJ because of the high intensity pulsed laser beam. The underlying mechanism of the periodic ripples formation could be explained by the K-H hydrodynamic instability theory. It had been shown that laser ablation with 600 mJ and 200 pulses results in the formation of many micro-cracks on the ablated area. Further analysis showed that the spatial occupation of the laser ablated area and the spacing between two adjacent ripples increased as the laser energy and the number of incident laser pulses increasing. The surface ripples feature on the edge of ablated area became more obvious with increasing laser pulses, but it was not correlated closely with the laser energies variation. [ABSTRACT FROM AUTHOR]

The interaction of high intensity laser radiation with an underdense plasma may lead to the formation of electron vortices. Though being quasistationary on the electron timescales, these structures tend to expand on a proton timescale due to Coulomb repulsion of ions. Using a simple analytical model of a stationary vortex as an initial condition, 2D PIC simulations are performed. A number of effects are observed such as vortex boundary field intensification, multistream instabilities at the vortex boundary, and bending of the vortex boundary with the subsequent transformation into smaller electron vortices. [ABSTRACT FROM AUTHOR]

ObjectivesThe aim of this study was to investigate factors affecting ablative efficiency of high intensity focused ultrasound (HIFU) for adenomyosis.Materials and methodsIn all, 245 patients with adenomyosis who underwent ultrasound guided HIFU (USgHIFU) were retrospectively reviewed. All patients underwent dynamic contrast-enhanced magnetic resonance imaging (MRI) before and after HIFU treatment. The non-perfused volume (NPV) ratio, energy efficiency factor (EEF) and greyscale change were set as dependent variables, while the factors possibly affecting ablation efficiency were set as independent variables. These variables were used to build multiple regression models.ResultsA total of 245 patients with adenomyosis successfully completed HIFU treatment. Enhancement type on T1 weighted image (WI), abdominal wall thickness, volume of adenomyotic lesion, the number of hyperintense points, location of the uterus, and location of adenomyosis all had a linear relationship with the NPV ratio. Distance from skin to the adenomyotic lesion’s ventral side, enhancement type on T1WI, volume of adenomyotic lesion, abdominal wall thickness, and signal intensity on T2WI all had a linear relationship with EEF. Location of the uterus and abdominal wall thickness also both had a linear relationship with greyscale change.ConclusionThe enhancement type on T1WI, signal intensity on T2WI, volume of adenomyosis, location of the uterus and adenomyosis, number of hyperintense points, abdominal wall thickness, and distance from the skin to the adenomyotic lesion’s ventral side can all be used as predictors of HIFU for adenomyosis. [ABSTRACT FROM PUBLISHER]

The article reports a study that investigated the efficacy, maternofetal responses, and safety of using high-intensity focused ultrasound (HIFU) treatment for twin-twin transfusion syndrome (TTTS). The researchers compared the noninvasive occlusion of placental vasculature to sham treatment in anesthetized pregnant sheep. They found the cardiovascular and metabolic fetal responses suggesting that TTTS is safe and potentially translatable to human pregnancy.

We consider the requirements of the energy-control system of the PICO laser facility and describe a design of the calorimeter based on the proposed method of laser-radiation-energy measurements using the calorimeter-sensor thermal response. We present the results of an experimental study of the calorimeter temporal parameters and dynamic analog memory. [ABSTRACT FROM AUTHOR]