Strongly correlated superconductivity in a copper-based metal-organic framework with a perfect kagome lattice

Metal-organic frameworks (MOFs), which are self-assemblies of metal ions and organic ligands, provide a tunable platform to search a new state of matter. A two-dimensional (2D) perfect kagome lattice, whose geometrical frustration is a key to realizing quantum spin liquids, has been formed in the π - d conjugated 2D MOF [Cu₃(C₆S₆)] _n (Cu-BHT). The recent discovery of its superconductivity with a critical temperature T _c of 0.25 kelvin raises fundamental questions about the nature of electron pairing. Here, we show that Cu-BHT is a strongly correlated unconventional superconductor with extremely low superfluid density. A nonexponential temperature dependence of superfluid density is observed, indicating the possible presence of superconducting gap nodes. The magnitude of superfluid density is much smaller than those in conventional superconductors and follows the Uemura's relation of strongly correlated superconductors. These results imply that the unconventional superconductivity in Cu-BHT originates from electron correlations related to spin fluctuations of kagome lattice.

5-fs, Multi-mJ, CEP-locked parametric chirped-pulse amplifier pumped by a 450-nm source at 1 kHz

We report on the development of an optical parametric chirpedpulse amplifier at a 1-kHz repetition rate with a 5.5-fs pulse duration, a 2.7-mJ pulse energy and carrier-envelope phase-control. The amplifier is pumped by a 450-nm pulse from a frequency-doubled Ti:sapphire laser.

The effect of core framework designs on the fracture loads of all-ceramic fixed partial dentures on posterior implants

This study evaluated the fracture loads of three-unit all-ceramic bridges on implants; the core frameworks of the bridges were made of zirconium oxide. Three core framework designs were fabricated according to the design of the bars between the retainers: (i) straight, (ii) curved in the occlusal direction, or (iii) curved in the gingival direction. A static load was applied at the centre of the pontic, and the mean initial crack and final fracture loads were measured and compared. The core framework curved in the occlusal direction had the highest final fracture loads; there were significant differences (P < 0.05) in the mean final fracture load, whereas initial fracture load, which fractured of veneered porcelain, did not show significant differences among three designs. The all-ceramic bridges on the implants made with Procera zirconium core frameworks had high final fracture load. The core framework design that curved in the occlusal direction helped the framework withstand the occlusal load, which results in reliable prostheses, especially in the molar region.

Observation of light-phase-sensitive photoemission from a metal

We demonstrate that multiphoton-induced photoelectron emission from a gold surface caused by low-energy (unamplified) 4-fs, 750-nm laser pulses is sensitive to the timing of electric field oscillations with respect to the pulse peak. This observation confirms recent theoretical predictions and opens the door to measuring the absolute value of the carrier-envelope phase difference of few-cycle light pulses with a solid-state detector.

Generation of two-color femtosecond pulses by self-synchronizing Ti:sapphire and Cr:forsterite lasers

We report a novel technique for the synchronization of two different femtosecond solid-state lasers by crossing of both laser pulses in a Kerr medium. Stable dual-wavelength femtosecond pulses at central wavelengths of 820 and 1250 nm have been obtained. The tolerance of cavity-length mismatch is ~0.6mum , where the pulse widths of the Ti:sapphire and the Cr:forsterite lasers are 18 and 40 fs, respectively, at average powers of 600 and 110 mW. The typical timing jitter derived from the cross correlation is less than 3 fs.

Single-shot measurement of carrier-envelope phase changes by spectral interferometry

We demonstrated single-shot measurements of spectral interference between a white-light continuum generated in a hollow-fiber and its second harmonic. The interference has information on the carrier-envelope phase of an input pulse to the fiber and the time delay of the blue wing of the continuum. By analyzing the observed spectral interference, we estimated shot-by-shot changes of the carrier-envelope phase. This method is useful for determining the carrier-envelope phase changes of a low-repetition-rate, high-intensity laser.

Carrier-phase control among subharmonic pulses in a femtosecond optical parametric oscillator

We have generated femtosecond subharmonic pulses by using an optical parametric oscillator. The optical frequencies of the idler and the signal are one third and two thirds, respectively, of the optical frequency of the pump pulse. The carrier phase of the signal pulse relative to that of the pump pulse was locked by electronic feedback. The carrier-envelope phase slip frequency of the signal pulse relative to that of the pump was locked to F/6 , where F is defined as the repetition frequency.

High-Average-Power Self-Starting Mode-Locked Ti:sapphire Laser With a Broadband Semiconductor Saturable-Absorber Mirror

We present a novel high-power, self-starting mode-locked Ti:sapphire laser with a semiconductor saturable-absorber mirror as the starter element. This laser, whose slope efficiency is 22%, generates pulses with an average power as high as 1.7 W and a pulse width as short as 16 fs. The self-starting process is also investigated.

Timing jitter in a kilohertz regenerative amplifier of a femtosecond-pulse Ti:Al(2)O(3) laser

We measure the timing error of femtosecond pulses amplified by a Ti:sapphire regenerative amplifier at a 1-kHz repetition rate by use of a modified cross-correlation technique. Linearly frequency-chirped amplified pulses are frequency mixed with transform-limited oscillator pulses. A shift in the sum frequency corresponds to the timing error of each amplified pulse relative to the oscillator pulses. The timing error was measured every 6 ms with approximately 1-fs resolution over a measurable range of 400 fs.

Measurement of the optical phase relation among subharmonic pulses in a femtosecond optical parametric oscillator

We observed the phase relation among subharmonic pulses generated by a femtosecond optical parametric oscillator (OPO). The ratio of the optical frequencies of the idler, the signal, and the pump pulses was set to 1:2:3. Under these conditions the wavelengths of the second harmonic of the signal pulse and the sum frequency between the pump and the idler pulses are the same. The beat signal between these two pulses represents the phase relationship among the pump, the signal, and the idler. The beat frequency varied when the cavity length of the OPO was changed.

Self-starting mode-locked Cr(4+):YAG laser with a low-loss broadband semiconductor saturable-absorber mirror

We report a self-starting mode-locked Cr(4+):YAG laser with a low-loss broadband metal reflector-based semiconductor saturable-absorber mirror. The minimum pulse width was 44 fs at a wavelength of 1520 nm.

[Phase 2 clinical study of 123I-IBF, a dopamine D2 receptor imaging agent, to evaluate clinical efficacy and safety in Parkinson's disease and Parkinson syndromes]

A Phase 2 multicenter trial of 123I-IBF, (S)-5-iodo-7-N-[(1-ethyl-2- pyrrolidinyl)methyl]carboxamido-2,3-dihydrobenzofuran, was conducted to evaluate its clinical efficacy and safety in 158 patients with Parkinson's disease (PD) or Parkinson syndromes (PS). SPECT data were acquired at two hours (2H-SPECT), after intravenous injection of 123I-IBF (167 MBq). Additional SPECT scan at three hours (3H-SPECT) and dynamic SPECT scan at most until one hour were performed when possible. No severe side effects due to 123I-IBF injection were observed. The sensitivity, specificity and accuracy for discriminating PS from PD using the striatal specific binding count-to-frontal cortex count ratio (St/Fc-1) in 3H-SPECT were 72.7%, 81.0% and 78.1% in 64 clinically definite cases (i.e., typical cases), respectively. The putamen-to-caudate ratios were significantly lower in striatonigral degeneration compared with those in PD. The contralateral-to-ipsilateral ratios against the symptomatic side of tremor and/or rigidity in the patients with PD (Hoehn & Yahr I) were significantly higher than the left-to-right ratios in the normal controls. St/Fc-1 in 3H-SPECT was significantly lower in the patients showing a poor response to levodopa than in those showing a good response. The dopamine D2 receptor binding potential (k3/k4), obtained by dynamic SPECT based on compartment model analysis, correlated well with the striatal specific binding count-to-occipital cortex count ratio. These results suggest that 123I-IBF is a promising agent for differential diagnosis and pathophysiological evaluation of PD and PS.

Generation of 12-fs pulses from a diode-pumped Kerr-lens mode-locked Cr:LiSAF laser

We demonstrate 12-fs-pulse generation from a diode-pumped Kerr-lens mode-locked Cr:LiSAF laser. This is to our knowledge the shortest pulse ever produced from a mode-locked Cr:LiSAF laser. Based on an improved estimation of the intracavity dispersions, we utilized BK7 glass for the Brewster-prism-pair material.

Stable mode-locking operation in a Cr:forsterite laser with a five-mirror cavity

The experimental finding of more-stable mode-locking operation in a five-mirror cavity than in a conventional four-mirror cavity for a Cr:forsterite laser [IEEE J. Quantum Electron. 33, 1975 (1997)] was interpreted by ABCD-matrix formalism. Since the optimum cavity configuration operation for mode-locking operation was attainable in the middle of the stable cavity condition, we conclude that one can easily achieve KLM alignment and stable mode locking with a five-mirror cavity.

[Present and future of nuclear medicine]

In this age of "Medical Imaging", Nuclear Medicine has occupied a preeminent position, heralded by the following four points: the development of novel radio-nuclides containing compounds (radio-diagnostic and radio-therapeutic agents), the power of extremely sensitive new measuring devices, the highly reliable quantification of physio-pathological changes occurring in disease and the guidance to medical diagnosis. On those four points, Nuclear Medicine will continue to spread, but new frontiers are emerging, and it is challenged to provide measurements of consistently reliable accuracy to guide various forms of treatment and radiotherapy requiring a high standard of competence.

Diode-Pumped Cr:forsterite Laser Mode Locked by a Semiconductor Saturable Absorber

We report the passive mode locking of a diode-pumped Cr:forsterite laser using a semiconductor saturable absorber. The laser generates 10-pJ pulses as short as 1.5 ps in duration with ~650 mW of absorbed pump power. We measured the transient reflectance of the saturable absorber mirror under different incident energy fluences by using a standard pump-probe method. The performance of this laser is also compared with a high-power fiber-laser-pumped femtosecond forsterite laser mode locked with the same absorber.

Broadband semiconductor saturable-absorber mirror for a self-starting mode-locked Cr:forsterite laser

We report a low-loss broadband semiconductor saturable-absorber mirror (SESAM) that uses gold film as the reflector. A semiconductor- SiO(2) double-layer stack enhances the reflectivity of the gold film. This low-loss SESAM was used in a mode-locked Cr:forsterite laser to produce self-starting 20-fs-scale laser pulses at 1.3 microm . The structure can be applied to SESAM's for other wavelengths.

Femtosecond Cr:forsterite laser diode pumped by a double-clad fiber

We present a compact, all-solid-state femtosecond Cr:forsterite laser. The laser is pumped by diodes through a double-clad fiber. Kerr-lens mode locking is initiated and stabilized by a semiconductor saturable-absorber mirror with a single InGaAs quantum well. This system generates transform-limited 80-fs pulses near 1.3microm . An average power of 68 mW with fluctuation of much less than 1% is obtained with 3.8 W of absorbed pump power. The stability, efficiency, compactness, and potential for scaling to higher power of this system make it an attractive short-pulse source for applications.

Self-starting mode-locked femtosecond forsterite laser with a semiconductor saturable-absorber mirror

We report on a self-starting mode-locked femtosecond Cr:forsterite laser pumped by a diode-pumped Nd:YVO(4) laser. The mode locking is initiated by a semiconductor saturable-absorber mirror (SESAM). We also present the measured group delay of the forsterite crystal and the SESAM.

[Effectiveness of the radioactive strontium (89Sr) chloride agent, SMS.2P for pain palliation in patients with metastatic bone tumor in phase III multicenter clinical trial]

The phase III clinical trial of strontium-89 chloride agent (SMS.2P) was performed in 90 patients with painful bone metastases secondary to prostate (53), breast (18) and other types of cancer (19). Some patients experienced a transient increase in pain or nausea and vomiting. However both symptoms subsided and serious side effects were not observed in any of the patients. As reported, we confirmed some abnormal changes in peripheral blood picture. A decrease in the number of white blood cells and platelets was considered to be partly a result of bone marrow suppression due to 89Sr irradiation. Pain was substantially improved after 89Sr therapy in 58% of the patients and there was some alleviation in 12%. The release from pain was accompanied by an improved quality of life for these patients including sleep patterns and morbidity. Some patients were able to resume their former life styles. Most of the improved patients experienced pain relief from days to one week following 89Sr therapy and in half cases, this remained effective for 2 or 3 months. There were even cases in which the pain relief continued over an observation period of time of clinical study.

[Measurement of serum tissue polypeptide antigen (TPA) in patients with malignant tumor using prolifigen TPA-M "Daiichi" kit]

Serum tissue polypeptide antigen (TPA) was measured using a newly developed Prolifigen TPA-M "Daiichi" kit in 1,236 healthy subjects, 2,867 patients with malignant tumors, and 901 with benign diseases. Because 94.0% of healthy subjects had serum TPA under 70 U/l, the cut-off value was set at 70 U/l. Serum TPA was elevated in more than 50% of patients with head and neck cancer, lung cancer, liver cancer, gallbladder or bile duct cancer, pancreatic cancer, colorectal cancer, ovarian cancer, and prostate cancer. The overall positive rate in malignant tumors was 55.5%. Serum TPA was higher in advanced cancer than in earlier stage cancer, and decreased after the resection of the tumor. The false positive rate in benign diseases was 31.3%. ROC analysis revealed the usefulness of TPA as a tumor marker in many cancers. The correlation coefficient between TPA and CYFRA 21-1, and between TPA and TPSA, was 0.747 and 0.694, respectively. In conclusion, measurement of serum TPA using the new kit is useful in the management of patients with various malignant tumors.

[A phase 3 clinical trial of 123I-iomazenil, a new central-type benzodiazepine receptor imaging agent (Part 3)--Report on clinical usefulness in epilepsy]

A Phase 3 clinical trial of 123I-Iomazenil (IMZ), a tracer which binds specifically to central-type benzodiazepine receptors (BZR), was performed, and the clinical usefulness of IMZ was evaluated in 121 patients with epilepsy (106 cases with partial epilepsy and 15 cases with generalized epilepsy). A regional abnormality in the BZR distribution was detected in late IMZ images in 20 of 24 cases without abnormal MRI and/or X-ray CT findings. Moreover, only 16 of these 20 cases showed abnormal findings in the cerebral blood flow (CBF) images. In partial epilepsy, abnormal regions in late IMZ images agreed or partially agreed with epileptic foci estimated from the clinical symptoms of epileptic seizures, interictal EEG, and MRI and/or X-ray CT findings in 76%, 70% and 96% of the cases detected. These regions also agreed or partially agreed with the estimated epileptic foci in 92% of the cases with foci estimated by combination of those three methods and in 72% of those estimated by ictal EEG. The agreement or partial agreement rates of late IMZ images with each of the other methods were higher than those of CBF images, although the differences were not significant. For surgically-proven epileptic foci without any abnormality in the CBF image, abnormal regions were detected in late IMZ images. These findings suggest that IMZ SPECT is a useful new tool for detecting epileptic foci based on the distribution of BZR in the brain.

[A phase 3 clinical trial of 123I-iomazenil, a new central-type benzodiazepine receptor imaging agent (Part 4)--Report on clinical usefulness in diagnosis of cerebrovascular diseases]

Single photon emission computed tomography (SPECT) using 123I-Iomanzenil (IMZ), a tracer which binds specifically to central-type benzodiazepine receptors, was performed in patients with cerebrovascular diseases (CVD) to determine the clinical signicigance of IMZ SPECT studies in evaluating the pathophysiology of CVD. IMZ SPECT images obtained three hours after administration of the tracer were compared with the images of cerebral blood flow (CBF) studies in 206 cases. In regions with decreased CBF, the uptake of IMZ was relatively preserved in patients with cerebral thrombosis in comparison with cerebral embolism, and in those with perforator branch infarction in comparison with cortical infarction. The uptake of IMZ decreased as a function of both the severity of the decrease in the CBF and the duration of illness in regions with a significantly decreased perfusion reserve. These results suggest that decreased IMZ binding in ischemic stroke reflects the neuronal damage caused by the cerebral ischemia. On the other hand, in patients with intracerebral hemorrhage, the cortical uptake of IMZ was relatively well-preserved in regions with decreased CBF, and the decrease in the uptake of IMZ was more profound as a function of the decrease in the CBF, especially in cases of putaminal hemorrhage. These results also suggest that the decreased cortical CBF is a remote effect caused by a neuronal disconnection, and neuronal damage may occur in regions with severely impaired CBF.

[A phase 3 clinical trial of 123I-iomazenil, a new central-type benzodiazepine receptor imaging agent (Part 1)--report on clinical usefulness in diagnosis of various brain diseases]

Iomazenil (IMZ) is a partial inverse agonist of central-type benzodiazepine receptors (BZR) which binds specifically to BZR with high affinity. The safety and clinical effectiveness of 123I-IMZ SPECT in the diagnosis of brain diseases were evaluated in 655 patients with various brain diseases, such as epilepsy, cerebrovascular diseases, degenerative diseases and mental disorders relating to BZR. This was a Phase 3 study conducted as a multicenter trial at 52 collaborating institutions. There was no significant adverse reactions in the clinical symptoms or abnormal laboratory test values. The investigators judged 123I-IMZ SPECT to be effective in 95% of 638 analyzed cases. The injected dose did not correlate with the image quality or the clinical effectiveness of 123I-IMZ SPECT, suggesting that these items depend largely on the characteristics of the apparatus used, the disease or pathology of the patients, rather than the dose. We conclude that 123I-IMZ imaging is safe and provides effective information based on BZR binding which is useful in the diagnosis of various brain diseases.

[A phase 3 clinical trial of 123I-iomazenil, a new central-type benzodiazepine receptor imaging agent (Part 2)--Report on clinical usefulness in diagnosis of degenerative neurological diseases and mental disorders]

Iomazenil (IMZ) is a partial inverse agonist of central-type benzodiazepine receptors (BZR) which binds specifically to BZR with high affinity. A multi-center Phase 3 clinical study was performed to evaluate the clinical usefulness of 123I-IMZ-SPECT in the diagnosis of brain disorders in 169 patients with degenerative neurological diseases and 37 patients with mental disorders such as neurotic, stress-related and somatoform disorders. In dementia, the decrease in activity in late images, obtained three hours after administration of 123I-IMZ, correlated negatively with the dementia score. In Parkinson's disease and spinocerebellar degeneration. 123I-IMZ showed a more profound decrease in uptake in late images than seen in the cerebral blood flow (CBF) images, and this decrease was in proportion to the duration and severity of the illness. In mental disorders, the ratio of the late to early image counts showed a negative correlation with Hamilton's anxiety scale in all regions in the brain cortices. In panic disorders, the ratio of the cerebral count to the cerebellar count in the late images correlated negatively with the severity of the attack in the frontal, temporal and parietal cortices. These results suggest that 123I-IMZ-SPECT enables us to evaluate the neuronal damage in degenerative diseases and the decrease in the BZR binding potential in mental disorders.