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This paper reviews and discusses the concept of nonlinear optical spectroscopy (NLOS) and microscopy employing ultra-broadband laser pulses. A spectral phase modulation technique of the ultra-broadband pulses, which allows the control of nonlinear optical processes, enables multimodal imaging in nonlinear optical microscopy. This technique uses the difference of the excitation spectra of molecules of interest. A spectroscopic technique combining NLOS with a Fourier-transform (FT) spectroscopy provides a broadband excitation spectrum with the bandwidth of the ultra-broadband pulse and a high spectral resolution in a single measurement. FT-NLOS can also be applied directly to multispectral microspectroscopy.

Background: Some reports have suggested the involvement of the D2 dopaminergic function in the expression of suicidal behavior. Here, we examined associations between suicide attempts and two kinds of functional polymorphisms in the dopamine D2 receptor (DRD2) gene, namely, TaqIA and –141C Ins/Del. Methods: Subjects included 120 suicide attempters and 123 unrelated volunteers. Those who attempted suicide were severely injured and were transferred to the emergency unit in our university hospital. To determine each genotype, we performed polymerase chain reaction and restriction fragment length polymorphism analyses. Results: We found significant differences in genotypic and allelic frequencies of –141C Ins/Del and TaqIA polymorphisms between suicide attempters and healthy controls (–141C Ins/Del, p = 0.01; TaqIA,p = 0.036). The Ins allele of –141C Ins/Del was significantly more frequent in suicide attempters (p = 0.011), as well as the A2 allele of TaqIA (p = 0.017). Haplotype analysis revealed no significant linkage disequilibrium between –141C Ins/Del and TaqIA polymorphisms (D′ = 0.226, r2 = 0.016, p = 0.10). Conclusions: These findings suggest that DRD2 gene polymorphisms may be involved in the biological susceptibility to suicide.

一般歯科医院において3ヶ月から12ヶ月間隔で15年以上32年の間メインテナンスを受けている患者291名の歯の喪失について後ろ向きの調査を行った。患者の平均年齢は39歳で女性が186名, 男性が105名であった。平均26年間のメインテナンス期間中, 1本も歯を失わなかった人は111名, 全体の38.2%であった。歯周基本治療終了後の総歯数は7536本, メインテナンス期間中の喪失歯の総数は626本 (8.3%)で一人当たりの平均喪失歯数は2.2本であった。喪失の原因は歯周疾患が157本 (2.1%), 歯周疾患以外が469本 (6.2%)であった。喪失歯数は大臼歯が一番多く, 一番少なかったのは下顎の犬歯だった。また, 歯の喪失は両側性にほぼ左右対称に進行していくことが示された。今回の我々の調査により, 長期のメインテナンスが歯の喪失を抑制するために効果的である可能性が示唆された。日本歯周病学会会誌 (日歯周誌)51 (2) : 169-174, 2009

We have developed and demonstrated a pointing and power stabilization system for intense few-cycle pulse generation at high repetition rates. The output power from a 1 kHz Ti:sapphire laser system was controlled by the voltage applied to a Pockels cell, and the beam pointing was controlled by a fast analog device composed of a position-sensitive detector and a piezo-driven mirror. As a result, the pointing and power fluctuations were stabilized within 1 µm rms and 0.15% rms, respectively, by feedback control. After spectral broadening inside a hollow fiber for pulse compression, the fluctuations in the output power and spectral intensity were 1.1% rms and 3.5% rms, respectively. Finally, we obtained stable intense few-cycle pulses with an energy of 2.7 mJ and a pulse duration of 5.4 fs.

We propose nonlinear Fourier-transform spectroscopy using a broadband pulse, which can discriminate the origin in Four-wave mixing (FWM) process. By taking account of the response function of a sample in the third-order interferometric autocorrelation (IAC) signal, we theoretically analyze FWM-FTS using a broadband pulse. The discrimination of the origin is achieved by taking advantage of the FWM power spectrum obtained by the Fourier-transform of the IAC signal. In the FWM power spectrum, there are frequency components, which indicate the effects of the two-photon electronic resonance and the Raman resonance. By focusing into the frequency components, the origin in FWM process is identified. Based on the theoretical analysis, we experimentally demonstrate nonlinear FTS employing the tightly focused pulse with a pulse duration of 5 fs and measure the Raman and two-photon electronic spectra in FWM process.

We review generation of intense high-order harmonics and its application to nonlinear multiphoton processes in atoms and molecules. Phase-matched high harmonics by a loosely focusing geometry produce highly focusable intensity with fully spatiotemporal coherence, which is sufficient to induce nonlinear optical phenomena in the extreme ultraviolet and soft X-ray (XUV) region where no intense coherent sources had previously existed. Observation of two-photon double ionization as well as two-photon above-threshold ionization in He is demonstrated with 42-eV high-harmonic photons. These nonlinear processes allow us to measure directly the temporal shapes of XUV high-harmonic pulses of which duration should be shorter than 1 fs. By combining intensity autocorrelation and photoelectron spectroscopy in two-photon above threshold ionization in Ar, temporal characterization of a train of attosecond pulses is achieved. On the other hand, when intense high harmonics around 20 eV is subjected to N 2 molecules, occurrence of Coulomb explosion following two-photon double ionization is observed in attosecond temporal precision. Taking advantage of larger cross section of two-photon ionization in molecules, we successfully perform the interferometric autocorrelation of an attosecond pulse train with the ion signals produced by Coulomb explosion of nitrogen molecules. The result reveals the phase relation between attosecond pulses in the train.

We demonstrate optical drive with 1.16-PHz frequency using gallium nitride (GaN) wide-bandgap semiconductor. An isolated attosecond pulse with coherent broadband spectrum reveals dipole oscillation with 860-as periodicity in the GaN electron and hole system.

We demonstrate a novel light source based on coherent two-channel waveform multiplexing employing 28-fs carrier-envelope-phase stable pulses. The two-channel pulse energy reaches 50 mJ, which is the highest energy ever reported for a parallel synthesizer.

Plasma-induced frequency shift can be found in angularly resolved harmonic spectrographs by non-collinear high-harmonic generation. Based on the results we derive time-dependent ionization degree of the gaseous medium during high-harmonic conversion process.

We investigate the characteristics of an all-reflective interferometric autocorrelator in which the reflective beam splitter has functions as a beam splitter and an optical delay line. Theoretical autocorrelation functions are derived as functions of the beam profile, gap width, and alignment conditions. The results are compared with experiments in order to verify their practical use.

We present the design concept of a setup of a pulse shaper to be used for high-power femtosecond lasers. The pulse shaper is constructed from a high-damage threshold fused-silica spatial light modulator and a 4-f optical system based on the design concept to avoid optical damage. We have successfully demonstrated a pulse compression of 20 fs, 5 mJ pulses obtained from a 1 kHz repetition rate Ti:sapphire chirped pulse amplification system at an average power of 5 W.

背景．自然気胸を初発とする肺癌は稀であり，自然気胸を契機に発見された微小肺癌症例を経験したので報告する．症例．53歳，男性．2006年5月，呼吸困難感を自覚し，前医を受診した．左自然気胸と診断され，当院紹介となり，胸腔ドレナージが施行された．自然気胸は改善したが，胸部CTにて左S1＋2胸膜直下に胸膜陥入を認め，周囲にGGOを伴った径10 mmの結節影を認めた．2ヶ月の経過観察にて結節影は消退せず，充実部分の増大および胸膜陥入の増悪傾向がみられたため，同年7月胸腔鏡下肺生検を施行し，肺腺癌と診断した．左肺上大区域切除およびリンパ節郭清術を引き続き行い，病理組織学的には腫瘍径7×7×5 mmの，高分化型腺癌pT1N0M0 stage IAと診断した．結論．近年，CT画像の向上とともに微小肺癌が発見される機会が増えつつあり，自然気胸症例といえどもCTの画像評価は，腫瘍性病変を見落とさないように慎重に行うべきである．周囲にGGOを伴う結節性小型病変は，悪性である可能性があり，経過観察にて消退しない場合，肺癌の可能性を念頭において精検すべきである．

Numerous reports have described differences in the distribution of orbitofrontal cortex (OFC) sulcogyral patterns between patients with schizophrenia (SZ patients) and healthy controls (HC). Alterations in OFC morphology are also observed in those at high risk for developing SZ and in first-episode SZ, suggesting that genetic associations may be extant in determining OFC sulcogyral patterns. We investigated the association between single nucleotide polymorphisms (SNP) in NRG1 and OFC sulcogyral patterns.A total of 59 Japanese patients diagnosed with SZ and 60 HC were scanned on a 1.5-T magnet. Patients were also assessed clinically. OFC sulcogyral patterns were evaluated for each participant, and genotyping was performed for four SNP in NRG1 (SNP8NRG243177, SNP8NRG221533, SNP8NRG241930, and rs1081062).There were significant differences in the distribution of OFC sulcogyral patterns between SZ patients and HC (χ(2) = 6.52, P = 0.038). SZ patients showed an increase in the frequency of Type III expression, which was associated with an earlier age of disease onset (β = -0.302, F = 4.948, P = 0.030). Although no difference was found in genotype frequencies between SZ patients and HC, an NRG1 SNP, SNP8NRG243177, was associated with Type II expression in SZ patients (β = 0.237, F = 4.120, P = 0.047).Our results suggest that OFC sulcogyral pattern formation in schizophrenia may be associated with NRG1 allele frequency, which is closely related to neurodevelopment.

We characterized a dipole response with an inner shell induced by an isolated attosecond pulse. We reconstruct the dipole response from the spectral interferogram constructed with two fields of electromagnetic radiation in a neon atom.

Transient fluorescent variations of enhanced green fluorescent protein and enhanced yellow fluorescent protein indicate the existence of two transient dark states including the lowest triplet state and the other dark state with a longer life time.

High-harmonic generation by non-collinear wave mixing in ionized media is demonstrated, in which the phase matching is realized in the direction of difference frequency mixing. The emission angle temporally varies depending on the ionization degree.

We aimed to design a rapid and reliable method to identify coronary lesions at high risk for the no-reflow phenomenon before elective coronary stent implantation using integrated backscatter intravascular ultrasound (IB-IVUS). The no-reflow phenomenon occurring during elective percutaneous coronary intervention (PCI) worsens patient prognosis, regardless of whether the phenomenon is transient or persistent. We retrospectively studied 353 coronary lesions to identify factors potentially promoting the no-reflow phenomenon, including lesion location and severity. We also performed component analysis by two- and three-dimensional IB-IVUS before elective stent implantation. The cutoff values of the true lipid volume and estimated lipid volume (lipid area at the minimal lumen diameter site × total stent length) for the no-reflow phenomenon were determined by receiver operating curve analysis. Type C lesions, regardless of location and a thrombolysis in myocardial flow grade of 0, were risk factors for the no-reflow phenomenon during PCI. The estimated lipid volume was significantly correlated with the true lipid volume (R 2 = 0.778, p

A completely dense femtosecond optical supercontinuum is observed for the first time. It does not exhibit the oscillation-like frequency structure of the well-known optical supercontinuum generated by self-phase modulation. The newly observed optical supercontinuum is attributed to bremsstrahlung radiation from electrons that tunnel the bound potential under a strong optical field. The basic properties of the dense optical supercontinuum are studied.

9-Hydroxy-10-oxo-12(Z),15(Z)-octadecadienoic acid (KODA) induces flowers in Lemna paucicostata after reacting with catecholamine (Yokoyama et al. 2000; Yamaguchi et al. 2001), and changes in endogenous KODA levels during the flower-inductive phase in short-day-induced cotyledons are closely related to flower induction (Suzuki et al. 2003). Here, we examined the change of KODA level after the flower induction period. KODA showed a transient increase in immature flower buds in all the plants we examined, i.e., Pharbitis nil, Dianthus caryophyllus L., Dendranthema grandiflorum Kitam. and Eustoma russellianum Griseb. No such increase of KODA was seen in foliar buds of P. nil. These phenomena indicate that KODA may be involved in flower formation, as well as flower induction.

A pressure gradient method for spectral broadening of intense-femtosecond laser pulses in gas-filled hollow fiber is proposed. The simulations using input energy of 6 mJ and pulse duration of 40 fs have shown that using the same value of ∫ p(x)dx, the energy transmittance can be enhanced by a factor of 25% compared to that of using constant gas pressure while the global spatial phase is also improved.

The nonlinear susceptibility of atoms interacting with an intense laser field has been investigated using numerical solution of the time-dependent Schrödinger equation. It was found that the behavior of nonlinear susceptibility strongly depends on the intensity; it increases linearly in low intensity regime (Kerr nonlinearity), then saturates at higher intensity. Furthermore, it has also been found that the nonlinear susceptibility is substantially influenced by the onset of ionization.

The two-photon excitation fluorescence (TPEF) process of an enhanced green fluorescent protein (EGFP) for fluorescence signals was adaptively controlled by the phase-modulation of femtosecond pulses. After the iteration of pulse shaping, a twofold increase in the ratio of the fluorescence signal to the laser peak power was achieved. Compared with conventional pulses optimized for peak power, phase-optimized laser pulses reduced the bleaching rate of EGFP by a factor of 4 while maintaining the same intensity of the fluorescence signal. Our method will provide a powerful solution to various problems confronting researchers, such as the photobleaching of dyes in two-photon excitation microscopy.

A simple and reliable “modeless” dye laser is created. Spectrally dense, tunable generation of strongly suppressed mode structure of about 6 GHz bandwidth is obtained. The laser parameters allow to detect simultaneously the entire inhomogeneously broadened spectral line for a number of practical cases.

We have developed a novel interferometric autocorrelator composed of only reflective elements, which functions as a beam splitter and an optical delay line. Analytical expressions are derived to give second-order autocorrelation functions and deconvolution factors for various conditions. The measurement of femtosecond laser pulses by interferometric autocorrelation is demonstrated in the visible region. The results are compared with those by calculation.

We examine the mechanism of photobleaching of fluorescent proteins using nonlinear Fourier-transform spectroscopy with ultrabroadband femtosecond pulses. Photobleaching of two-photon excited fluorescent molecules occurs through one-photon excited-state absorption.

The use of hollow-core optical fibers in ultrafast nonlinear optics opens up the way to provide favorable conditions in the interaction between optical waves and gaseous media. The fundamental properties of optical waves propagating in a hollow fiber and various nonlinear phenomena generated inside the fiber are described.

In many atomic, molecular and solid systems, Lorentzian and Fano profiles are commonly observed in a broad research fields throughout a variety of spectroscopies. As the profile structure is related to the phase of the time-dependent dipole moment, it plays an important role in the study of quantum properties. Here we determine the dipole phase in the inner-shell transition using spectral phase interferometry for direct electric-field reconstruction (SPIDER) with isolated attosecond pulses (IAPs). In addition, we propose a scheme for pulse generation and compression by manipulating the inner-shell transition. The electromagnetic radiation generated by the transition is temporally compressed to a few femtoseconds in the extreme ultraviolet (XUV) region. The proposed pulse-compression scheme may provide an alternative route to producing attosecond pulses of light., Characterizing and understanding the profile of atomic spectral lines tells us a great deal about an atom’s properties. Here, the authors combine attosecond transient spectroscopy and the SPIDER technique to reconstruct the dipole oscillation phase of the auto-ionisation inner-shell transition in neon.

We present results from interaction of helium with intense, femtosecond laser pulses. Using spectral methodfor selecting the harmonics, it can be shown that under certain condition, a single femto or subfemtosecondharmonic pulses as well as train of attosecond pulses can be generated from femtosecond intense driving field.

The mutual interference between the transient stimulated Raman scattering and the self-phase modulation was considered a long time ago [Phys. Rev. A 2 (1970) 60]. In this work we have studied experimentally, for the first time to our knowledge, the influence of the transient stimulated Raman scattering on the self-phase modulation, considering single-shot Raman spectra. The stimulated Raman scattering was excited in methane by 140 fs pulses of the fundamental wave of a Ti:sapphire laser. Narrowing of the Stokes spectrum and suppression of the self-phase modulation structure were observed with increasing Raman gain, in agreement with the theoretical predictions. The effect has been observed up to 40 atm of methane pressure.

The generation and propagation of attosecond pulses in He gas by using intense sub-10-fs driver pulse are numerically investigated. It is shown that a single attosecond pulse can be generated by Fourier synthesis of selected successive harmonics either in the cutoff or in the plateau regions of spectrum. In both cases the maximal electric field intensity and the duration of the attosecond pulse can be controlled by appropriately choosing the propagation length.

Because of the low Cr/sup 4+/ concentration in Cr/sup 4+/: YAG crystals, the output energy of the Cr/sup 4+/:YAG laser is limited by the ground-state depletion of Cr/sup 4+/ when pumped by a Q-switched Nd:YAG laser. We propose and demonstrate a double-pulse pumping technique to improve the output power and energy, by which a Cr/sup 4+/ ion that returns to the ground state during lasing is repumped by the second pump pulse and can immediately contribute to lasing. The output power and energy were increased by factors of 5 and 4, respectively, from those in conventional single-pulse pumping. These enhancement factors were limited by the relaxation time from the higher excited state following excited-state absorption to the upper laser level. In addition to the fast relaxation reported so far, we found that there is a slow relaxation channel with a time constant of approximately 100 ns, which was also explored by using the double-pulse pumping technique.

High-harmonic generation in He atoms illuminated by high-intensity femtosecond excitation pulses is studied. It is shown that single attosecond pulses as well as trains of several attosecond pulses, one per half a period, can be generated in the multicycle regime of the driver pulse.

We prospectively examined the survival rate of 67 chronic obstructive pulmonary disease (COPD) and 74 late sequelae of pulmonary tuberculosis (TB seq) patients to clarify whether nocturnal oxyhemoglobin desaturation (NOD)could be one of the independent factors determining their mortality. The sleep monitoring of arterial oxygen saturation (SpO2) and pulmonary function tests were assessed in all patients at the time of registration. Forty %of COPD and 24%of TB seq died as the direct result of deterioration of chronic respiratory failure during the 7-year observation period. Cox's proportional hazards analysis showed that NOD was an independent prognostic factor in both groups, and this was especially prominent when evaluated in terms of sleep lowest SpO2 in COPD and 85% desaturation time in TB seq. No significant prognostic factor was observed among age, vital capacity percent predicted (%VC), forced expiratory volume in one second (FEV1.0%)and partial pressure of carbon dioxide (PaCO2). We conclude that the degree of NOD can affect mortality in COPD and TB seq.(Internal Medicine 37: 354-359, 1998)

We demonstrate that temporal focusing microscopy with structured illumination provides super-resolution even if wavefront distortion within the sample results in stretching the point spread function of the microscope.

We present the measurement of photobleaching spectra of fluorescent proteins with nonlinear Fourier-transform spectroscopy using ultrabroadband femtosecond pulses. Photobleaching of two-photon excited fluorescent molecules occurs through one-photon excited-state absorption.

We temporally manipulated optical field emitted from autoionizing transition stimulated by isolated attosecond pulse. The controlled optical field has approximately 1-eV bandwidth, which corresponds to approximately 2 fs duration.

The FT-IR spectra of clusters of UF6 seeded in argon were measured in a continuous supersonic Laval nozzle flow. We observed absorption peaks of UF6 clusters on both the red- and the blue-shifted sides of the monomer peak (around 627 cm−1) at a temperature below 130 K. We assigned these peaks using calculated results on the frequency shifts and transition strength of the IR spectra of UF6 clusters. Clusters as large as 10 in size were found to be formed under our experimental conditions. Vibrational predissociation of UF6 clusters was observed after a single shot from a Raman laser tuned to a vibrational mode of the UF6 clusters (614.8 cm−1) in the Laval nozzle. We monitored the concentration of UF6 monomers in the ground state with a diode laser spectrometer, and qualitatively interpreted the time-scale of the predissociation of the UF6 clusters and the recombination of UF6 monomers subsequent to the predissociation in the nozzle. After the UF6 clusters had dissociated in less than 1 ns, the excited monomers formed by the dissociation were deactivated with a time constant of about 0.3 μs via vibrational relaxation induced by collisions with carrier gas (argon) atoms. The recombination of UF6 monomers produced by the vibrational predissociation competed with vibrational relaxation. The time constant of the recombination (about 6 μs) was found to be much larger than that of the relaxation.

Based on a calculation for the Raman gain coefficient of the S/sub 0/(2) transition in ortho-D/sub 2/, we have demonstrated the generation of first Stokes waves in the 15-16-/spl mu/m spectral region. Use of ortho-D enriched by a catalytic converter enabled us to realize efficient conversion at room temperature. Stokes energies as high as 400 mJ were obtained.