Phase-locking of octave-spanning optical frequency comb based on Kerr-lens mode-locked Yb:KYW laser to reference laser

We phase locked an octave-spanning optical frequency comb based on a laser-diode-pumped Kerr-lens mode-locked Yb:KYW laser to a reference laser. We controlled the cavity length of the mode-locked laser to phase lock the mode frequency of the comb to the reference laser. This was conducted using a fast piezoelectric-actuated mirror on a lead-filled mount, which was aimed at damping the mechanical resonances. We achieved a servo bandwidth of 200 kHz, a residual phase noise of 0.47 rad, and a power concentration to a carrier of 91%. To extend the locking duration of the carrier-envelope offset frequency, we compensated its slow drift using the position of the Yb:KYW crystal while the pump-laser power was controlled to achieve its phase locking. We continuously maintained the full phase locking of the comb for 3 h until the reference lasers were out of lock

Two-photon interference of photon pairs created in photonic crystal fibers

We investigate a method to produce photon pairs by four-wave mixing in photonic crystal fibers (PCFs). By controlling the wavelength of the pump light, which determines the phase matching condition for four-wave mixing, we can obtain a broader spectrum of photon pairs than undesired Raman-scattered photons. We observe two-photon interference of photon pairs from a PCF with the help of an unbalanced Mach-Zehnder interferometer. Two-photon interference fringes with 83% visibility, which exceeds the classical limit of 50%, are obtained.Comment: 5 pages, 6 figures, to be published in JPS

Comparison of Independent Optical Frequency Measurements Using a Portable Iodine-Stabilized Nd:YAG Laser

A comparison of two independent absolute optical frequency measurements has been carried out between the National Metrology Institute of Japan/National Institute of Advanced Industrial Science and Technology (NMIJ/AIST), Tsukuba, Japan and the JILA (formerly the Joint Institute for Laboratory Astrophysics), Boulder, CO, using a portable iodine-stabilized Nd:YAG laser. The agreement between the two absolute measurements is better than the measurement uncertainty of 6.7×10-13 that can be attributed to the reproducibility limitations of the portable laser. This comparison is used to confirm the measured absolute frequency of an iodine-stabilized Nd:YAG laser at NMIJ/AIST (Y3), which is reported to the Consultative Committee for Length (CCL) for the determination of the absolute frequency value of iodine-stabilized Nd:YAG lasers

Application of Compound Action Potential of Facial Muscles Evoked by Transcranial Stimulation as a Reference Waveform of Motor-evoked Potential in Spinal Surgery

Transcranial electrical stimulation motor-evoked potential (TES-MEP) has been widely used to monitor major motor pathways in cranial and spinal surgeries. However, the results of TES-MEP might be strongly influenced by anesthetic agents and muscle relaxants. To compensate for this effect, a technique using compound muscle action potentials of the abductor pollicis brevis (APB-CMAP) evoked by median nerve stimulation has recently been reported. In this article, we adopted the transcranial electrical stimulation motor-evoked potential of facial muscles (TES-FMEP) instead of APB-CMAP as a reference waveform for compensation. Intraoperative monitoring in spinal surgeries using TES-MEP, TES-FMEP and APB-CMAP was performed in 64 patients. We compared with and without compensation methods using TES-FMEP and APB-CMAP to evaluate TES-MEP. The cases which demonstrated postoperative motor disturbance, including transient symptoms, were judged to be positive cases. Postoperative transient paraplegia was shown in one intramedullary tumor case among those 64 cases. Compensation by TES-FMEP exhibited t he highest specificity (90.5%) and lowest false-positive rate (9.5%) among the three compensation modalities when evaluated at 80% amplitude decrease. TES-FMEP, being derived from motor cortex stimulation, is not influenced by the original spinal lesion or surgical manipulation of the spine. Therefore, compensation using TES-FMEP is suitable for intraoperative monitoring during spinal surgery. The authors advocate TES-FMEP as a reference waveform for the compensation of intraoperative TES-MEP

Poor performance on the Iowa gambling task in children with obsessive-compulsive disorder

Background: Several lines of evidence implicate orbitofrontal cortex dysfunction in the pathophysiology of obsessive-compulsive disorder (OCD). The purpose of this study was to investigate neuropsychological dysfunction of the orbitofrontal cortex in children with OCD. Methods: The Iowa Gambling Task (IGT), which reflects orbitofrontal cortex function, and the Wisconsin Card Sorting Test (WCST), which is associated with functioning of the dorsolateral prefrontal cortex, were administered to 22 children with OCD and 22 healthy controls matched for gender, age, and intelligence. Results: OCD patients displayed poor performance on the IGT. In contrast, performance on the WCST was not impaired in OCD patients compared to controls. Conclusions: These findings are in line with previous studies demonstrating that OCD in childhood is associated with a dysfunction of orbitofrontal-striatal-thalamic circuitry.ArticleANNALS OF GENERAL PSYCHIATRY. 11:25 (2012)journal articl

Pembrolizumab-induced hypothyroidism caused reversible increased serum creatinine levels: a case report

Background The advent of immune checkpoint inhibitors (ICIs) has significantly improved the prognosis of patients with advanced malignancies. On the other hand, these drugs might cause immune-related adverse events (irAEs) including endocrinopathies and nephropathies. Thyroid dysfunction is one of the most common irAEs. For ICIs-induced nephropathies, most cases are due to tubulointerstitial nephritis, which might require steroid treatment. Here, we report a patient with non-small cell lung cancer treated with ICI who developed increased serum creatinine (s-Cr) levels due to ICIs-induced hypothyroidism. Case presentation A 57-year-old Asian man with refractory non-small cell lung cancer under ICIs therapy (pembrolizumab, an anti-programmed cell death-1 monoclonal antibody) developed increased s-Cr levels 5 months after the pembrolizumab initiation. His laboratory data, renal biopsy, and Gallium-67 scintigraphy findings denied pembrolizumab-induced tubulointerstitial nephritis. His renal function was correlated with thyroid function. Despite the increase of s-Cr levels, serum cystatin C levels were normal, which could be explained by the hypothyroidism. Levothyroxine treatment improved renal function as well as thyroid function. Then pembrolizumab was resumed, and both his thyroid and renal function remained normal level. Ultimately, we concluded that the increased s-Cr levels were caused by pembrolizumab-induced hypothyroidism. Conclusion All clinicians involved in ICI treatment need to recognize the possible increase in s-Cr levels caused by ICIs-induced hypothyroidism, and we propose monitoring serum cystatin C levels to differentiate ICIs-induced hypothyroidism from tubulointerstitial nephritis before invasive renal biopsies or steroid treatment, which are recommended by the prescribing information for pembrolizumab, are performed

Characteristic findings in images of extra-pancreatic lesions associated with autoimmune pancreatitis

Purpose: Autoimmune pancreatitis is a unique form of chronic pancreatitis characterized by a variety of extra-pancreatic involvements which are frequently misdiagnosed as lesions of corresponding organs. The purpose of this study was to clarify the diagnostic imaging features of extra-pancreatic lesions associated with autoimmune pancreatitis. Materials and methods: We retrospectively analyzed diagnostic images of 90 patients with autoimmune pancreatitis who underwent computer-assisted tomography, magnetic resonance imaging, and/or gallium-67 scintigraphy before steroid therapy was initiated. Results: AIP was frequently (92.2%) accompanied by a variety of extra-pancreatic lesions, including swelling of lachrymal and salivary gland lesions (47.5%), lung hilar lymphadenopathy (78.3%), a variety of lung lesions (51.2%), wall thickening of bile ducts (77.8%), peri-pancreatic or para-aortic lymphadenopathy (56.0%), retroperitoneal fibrosis (19.8%), a variety of renal lesions (14.4%), and mass lesions of the ligamentum teres (2.2%). Characteristic findings in CT and MRI included lymphadenopathies of the hilar, peri-pancreatic, and para-aortic regions; wall thickening of the bile duct; and soft tissue masses in the kidney, ureters, aorta, paravertebral region, ligamentum teres, and orbit. Conclusions: Recognition of the diagnostic features in the images of various involved organs will assist in the diagnosis of autoimmune pancreatitis and in differential diagnoses between autoimmune pancreatitis-associated extra-pancreatic lesions and lesions due to other pathologies.ArticleEUROPEAN JOURNAL OF RADIOLOGY. 76(2):228-238 (2010)journal articl

Li diffusion in Lix_xCoO2_2 probed by muon-spin spectroscopy

The diffusion coefficient of Li$^+$ ions ($D_{\rm Li}$) in the battery material Li$_x$CoO$_2$ has been investigated by muon-spin relaxation ($\mu^+$SR). Based on the experiments in zero-field and weak longitudinal-fields at temperatures up to 400 K, we determined the fluctuation rate ($\nu$) of the fields on the muons due to their interaction with the nuclear moments. Combined with susceptibility data and electrostatic potential calculations, clear Li$^+$ ion diffusion was detected above $\sim150$K. The $D_{\rm Li}$ estimated from $\nu$ was in very good agreement with predictions from first-principles calculations, and we present the $\mu^+$SR technique as an % novel and optimal probe to detect $D_{\rm Li}$ for materials containing magnetic ions.Comment: 4 pages, 4 figures. accepted for publication in PR