Essential amino acid supplements ingestion has a positive effect on executive function after moderate-intensity aerobic exercise.

Aerobic exercise acutely improves cognitive function (e.g., executive function (EF); memory recognition (MR)) and increases circulating brain-derived neurotrophic factor (BDNF). In addition, branched-chain amino acids (BCAA) ingestion acutely shortens the choice reaction time and increases brain BDNF. We examined whether the ingestion of essential amino acid (EAA) supplements (mainly composed of BCAA) would positively impact on cognitive function and circulating BDNF after moderate-intensity aerobic exercise. Twenty-two healthy young men received either an EAA supplements or the placebo (PL) 30 min before undergoing aerobic exercise. The participants performed a cycling exercise at 60% of peak oxygen uptake for 30 min. EF after aerobic exercise was better after the EAA treatment than after the PL treatment (P = 0.02). MR (P = 0.38 for response accuracy; P = 0.15 for reaction time) and circulating BDNF (P = 0.59) were not altered by EAA supplements. EF improvement was correlated with increases in some amino acids (leucine, isoleucine, valine, lysine, phenylalanine; all Ps < 0.05) that are potential substrates for synthesizing neurotransmitters in the brain. These results suggest that EAA supplements ingestion had a positive effect on EF after moderate-intensity aerobic exercise, while MR and BDNF were not altered.

Optical thin film coated organic nonlinear crystal for efficient terahertz wave generation.

In the process of terahertz (THz) wave generation via optical rectification of infrared femtosecond pulses in a non-linear optical crystal, the power of terahertz wave is directly proportional to the square of the optical pump power. Therefore, high power terahertz wave can be generated using a high power femtosecond laser provided that the crystal has both high laser induced damage threshold and optical non-linear coefficient. However, a significant amount of pump power is lost in this process due to the Fresnel's reflection at the air-crystal boundary. In this paper, we numerically and experimentally demonstrate that the coat of optical thin film called Cytop on the 4-N, N-dimethylamino-4'-N'-methyl-stilbazolium tosylate (DAST) crystal effectively reduces the reflection loss of pump power, thereby increasing the THz wave emission efficiency of the DAST crystal. We found that the average power of THz wave emitted by the thin film coated crystal is about 28% higher than the THz power emitted by the uncoated crystal when an equal amount of laser power is used. The thin film coated DAST crystals can be used not only in terahertz measurement systems but also in optical devices such as modulators and waveguides.

Effects of Non-Essential Amino Acids on Knee Joint Conditions in Adults: A Randomised, Double-Blind, Placebo-Controlled Trial.

Joint problems impair performance during exercise and daily activities and influence quality of life. The present study aimed to examine the effects of a combination of six non-essential amino acids (6AA) on joint conditions in an adult population. A total of 50 participants aged between 20 and 64 years with joint discomfort but no diagnosed joint disorder were randomly and blindly assigned to a control or 6AA group. The 6AA group took 12 g of the non-essential amino acid formulation orally (4 g three times a day) and the control group took equivalent doses of a placebo. Each group maintained the daily dose for 12 weeks. Primary outcome measures were evaluated with the visual analogue scale (VAS), the Japanese Knee Osteoarthritis Measure (JKOM), and the Japanese Orthopaedic Association score (JOA). These tests were taken before the experiment began at 4 weeks and 12 weeks after the intervention. The results of the VAS indicated that 6AA improved joint pain, discomfort, and stiffness both during a resting state and during normal activity. Participants' scores on the JKOM and JOA also showed significant improvements in the group that had taken the 6AA supplement. These results demonstrate that 6AA improves symptoms of joint problems, such as pain, discomfort, stiffness, and difficulty in performing daily activities after 4 weeks of daily consumption.

Nonlinear optical process of second-order nonlinear optical susceptibility χ133(2) in an organic nonlinear optical crystal DAST.

A large unexamined second-order nonlinear optical (NLO) process is found in a 4-N,N-dimethylamino-4'-N'-methyl stilbazolium tosylate (DAST) crystal, which has a large figure of merit among NLO crystals. In second-order NLO processes using a DAST crystal, the χ111(2) process of light excitation is commonly used, involving a-axis polarized light excitation with light generation of a-axis polarized light. However, there have been few studies of other second-order NLO susceptibility processes to date. In this Letter, terahertz (THz) wave generation via second-order NLO processes based on the χ133(2) second-order NLO susceptibility of the DAST crystal was investigated. By adjusting the polarization direction of the excitation light using a prism-coupled Cerenkov phase-matching method, efficient generation of THz waves was achieved using a process involving χ133(2). The magnitude of the NLO constant χ133(2) estimated from the THz intensity ratio was 77.8 pm/V. These results indicate that prism-coupled Cherenkov phase matching can be used to identify undiscovered NLO processes for NLO crystals.

Asynchronous electric field visualization using an integrated multichannel electro-optic probe.

The higher the frequency, the more complex the scattering, diffraction, multiple reflection, and interference that occur in practical applications such as radar-installed vehicles and transmitter-installed mobile modules, etc. Near-field measurement in "real situations" is important for not only investigating the origin of unpredictable field distortions but also maximizing the system performance by optimal placement of antennas, modules, etc. Here, as an alternative to the previous vector-network-analyzer-based measurement, we propose a new asynchronous approach that visualizes the amplitude and phase distributions of electric near-fields three-dimensionally without placing a reference probe at a fixed point or plugging a cable to the RF source to be measured. We demonstrate the visualization of a frequency-modulated continuous wave (FMCW) signal (24 GHz ± 40 MHz, modulation cycle: 2.5 ms), and show that the measured radiation patterns of a standard horn antenna agree well with the simulation results. We also demonstrate a proof-of-concept experiment that imitates a realistic situation of a bumper installed vehicle to show how the bumper alters the radiation patterns of the FMCW radar signal. The technique is based on photonics and enables measuring in the microwave to millimeter-wave range.

Pump wavelength-independent broadband terahertz generation from a nonlinear optical crystal.

In nonlinear optical (NLO) crystals, the selection of pump light wavelengths for the generation of terahertz (THz) waves is limited due to problems associated with coherence length, refractive index, and absorption by the crystal. Relaxation of this limitation would open up potential light sources for THz generation. One such solution, Cherenkov phase matching, removes the coherence length constraint. In this study, we attempted to generate THz waves from an NLO crystal using femtosecond pulses of various wavelengths. Specifically, 805-nm and 1560-nm femtosecond pulses were used to pump a prism-coupled LiNbO3 crystal. Broadband THz-wave generation and a THz-wave output proportional to the square of the pump light intensity were observed at both wavelengths. The generation of THz waves by prism-coupled Cherenkov phase matching was not limited by the wavelength of the pump light. Moreover, THz-wave generation at even greater intensities may be possible by optimizing the pump source and coupling to an NLO crystal.

Mapping of electromagnetic waves generated by free-running self-oscillating devices.

Near-field mapping has proven to be a powerful technique for characterizing and diagnosing antennas in the microwave frequency range. However, conventional measurement methods based on a network analyzer cannot be applied to on-chip antenna devices extensively studied for future wireless communication in the millimeter wave (mm-wave) (30-300 GHz) and terahertz (THz) wave (0.1-10 THz) frequency regions. Here, we present a new asynchronous mapping technique to investigate the spatial distribution of not only the amplitude but also the phase of the electric field generated by free-running, self-oscillating generators including CMOS oscillators, Gunn oscillators, resonant tunneling diodes, and quantum cascaded lasers. Using a photonic-electronic hybrid measurement system, a wide frequency coverage, minimal invasiveness of the field to be measured, and phase distribution measurements with a theoretically-limited sensitivity are simultaneously achieved. As a proof-of-concept experiment, we demonstrate the mapping of a mm-wave (77 GHz) generated by a free-running Gunn oscillator and antenna characterization based on near-to-far field transformation.

Prism-coupled Cherenkov phase-matched terahertz wave generation using a DAST crystal.

Terahertz (THz) wave generation based on nonlinear frequency conversion is a promising method for realizing a tunable monochromatic high-power THz-wave source. Unfortunately, many nonlinear crystals have strong absorption in the THz frequency region. This limits efficient and widely tunable THz-wave generation. The Cherenkov phase-matching method is one of the most promising techniques for overcoming these problems. Here, we propose a prism-coupled Cherenkov phase-matching (PCC-PM) method, in which a prism with a suitable refractive index at THz frequencies is coupled to a nonlinear crystal. This has the following advantages. Many crystals can be used as THz-wave emitters; the phase-matching condition inside the crystal does not have to be observed; the absorption of the crystal does not prevent efficient generation of radiation; and pump sources with arbitrary wavelengths can be employed. Here we demonstrate PCC-PM THz-wave generation using the organic crystal 4-dimethylamino-N-metyl-4-stilbazolium tosylate (DAST) and a Si prism coupler. We obtain THz-wave radiation with tunability of approximately 0.1 to 10 THz and with no deep absorption features resulting from the absorption spectrum of the crystal. The obtained spectra did not depend on the pump wavelength in the range 1300 to 1450 nm. This simple technique shows promise for generating THz radiation using a wide variety of nonlinear crystals.

High-resolution time-of-flight terahertz tomography using a femtosecond fiber laser.

High-resolution tomographic imaging is demonstrated using a reflection-type terahertz time-domain spectroscopy. To realize a practical system for general use, a robust all-fiber laser was used as the pump light source. Broadband terahertz waves were generated with the combination of optical pulses compressed to 17 fs using optical fibers and a DAST crystal. Using deconvolution signal processing, the wideband spectrum of the generated terahertz waves provided high-axial resolution leading to successful imaging of a multilayered structure containing a 2-microm-thin GaAs layer. To our knowledge, this is the first demonstration of terahertz tomographic imaging of such a thin layer.

Field-size dependence of doses of therapeutic carbon beams.

To estimate the physical dose at the center of spread-out Bragg peaks (SOBP) for various conditions of the irradiation system, a semiempirical approach was applied. The dose at the center of the SOBP depends on the field size because of large-angle scattering particles in the water phantom. For a small field of 5 x 5 cm2, the dose was reduced to 99.2%, 97.5%, and 96.5% of the dose used for the open field in the case of 290, 350, and 400 MeV/n carbon beams, respectively. Based on the three-Gaussian form of the lateral dose distributions of the carbon pencil beam, which has previously been shown to be effective for describing scattered carbon beams, we reconstructed the dose distributions of the SOBP beam. The reconstructed lateral dose distribution reproduced the measured lateral dose distributions very well. The field-size dependencies calculated using the reconstructed lateral dose distribution of the therapeutic carbon beam agreed with the measured dose dependency very well. The reconstructed beam was also used for irregularly shaped fields. The resultant dose distribution agreed with the measured dose distribution. The reconstructed beams were found to be applicable to the treatment-planning system.

Dose contributions from large-angle scattered particles in therapeutic carbon beams.

In carbon therapy, doses at center of spread-out Bragg peaks depend on field size. For a small field of 5 x 5 cm2, the central dose reduces to 96% of the central dose for the open field in case of 400 MeV/n carbon beam. Assuming the broad beam injected to the water phantom is made up of many pencil beams, the transverse dose distribution can be reconstructed by summing the dose distribution of the pencil beams. We estimated dose profiles of this pencil beam through measurements of dose distributions of broad uniform beams blocked half of the irradiation fields. The dose at a distance of a few cm from the edge of the irradiation field reaches up to a few percent of the central dose. From radiation quality measurements of this penumbra, the large-angle scattered particles were found to be secondary fragments which have lower LET than primary carbon beams. Carbon ions break up in beam modifying devices or in water phantom through nuclear interaction with target nuclei. The angular distributions of these fragmented nuclei are much broader than those of primary carbon particles. The transverse dose distribution of the pencil beam can be approximated by a function of the three-Gaussian form. For a simplest case of mono-energetic beam, contributions of the Gaussian components which have large mean deviations become larger as the depth in the water phantom increases.

Coherent tunnelling conductance in magnetic tunnel junctions of half-metallic full Heusler alloys with MgO barriers.

We have carried out electronic structure and transport calculations for magnetic tunnel junctions (MTJ) composed of MgO and a half-metallic full Heusler alloy Co(2)MnSi on the basis of the density functional theory and the Landauer formula. We find that the density of states of Co atoms at the Co(2)MnSi/MgO(001) interface shifts toward the higher energy side due to the reduced symmetry, leading to a reduction of the spin polarization at the interface. Furthermore, we show that the majority-spin transmittance as a function of the in-plane wavevector [Formula: see text] has a broad peak centred at [Formula: see text] due to the tunnelling from the Δ(1) channel of Co(2)MnSi, while the transmittance from the Δ(5) channel is three orders of magnitude smaller than that of the Δ(1) channel. These results indicate that coherent tunnelling through the Δ(1) band is dominant also in an MTJ with Co(2)MnSi and an MgO barrier, like in Fe/MgO/Fe(001) MTJ and related systems.

[Development of the QA/QC-tools for CT number calibration of the treatment planning CT-scanner.].

In order to support a routine QA of the CT number for treatment planning, we developed a phantom and a sample holder for easy handling. At most particle radiotherapy facilities in Japan, the CT number is calibrated by the poly-binary calibration method using liquid samples of 100% ethanol and 40% K(2)HPO(4) which are set in a cylindrical water phantom. However it is hard to remove air bubbles from the calibration liquid sample and maintain its stable concentration for a long time. So much time is needed for QA of the CT number. The new sample holder, which we developed, was able to keep a stable concentration of the liquid for more than 300 days. Consequently, the CT number of each sample, which was set in a water equivalent solid phantom, was the same as the CT number in a water phantom within 7 HU. In addition, we developed software which could measure the CT number of each sample semi-automatically and could calculate the calibration coefficients between the CT number and water equivalent length (WEL). Using this software, we could check the calibration result instantly at the time of CT data acquisition. These tools should be useful to carry out calibration of the CT-WEL routinely in a short time.