Observation of a critical charge mode in a strange metal.

Understanding the strange metallic behavior that develops at the brink of localization in quantum materials requires probing the underlying electronic charge dynamics. Using synchrotron radiation-based Mössbauer spectroscopy, we studied the charge fluctuations of the strange metal phase of ß-YbAlB4 as a function of temperature and pressure. We found that the usual single absorption peak in the Fermi-liquid regime splits into two peaks upon entering the critical regime. We interpret this spectrum as a single nuclear transition, modulated by nearby electronic valence fluctuations whose long time scales are further enhanced by the formation of charged polarons. These critical charge fluctuations may prove to be a distinct signature of strange metals.

Establishment of an objective index for the diagnosis of attention deficit/hyperactivity disorder by the continuous performance test "MOGRAZ".

OBJECTIVE: The diagnosis of attention deficit/hyperactivity disorder (AD/HD) in Japan is mainly based on information obtained from caregivers. There is therefore a need to establish an objectivity index that can be easily used in clinical practice. The purpose of the study was to create a predictive model for the diagnosis of AD/HD using the MOGRAZ, a visual continuous performance test developed in Japan. METHODS: We collected data from an AD/HD group and a non-AD/HD group. The AD/HD group included 75 children with predominantly inattentive type AD/HD and 48 with combined type AD/HD who were aged 6 to 12 years and diagnosed at our department. The non-AD/HD group included 153 Japanese children aged 6 to 11 years enrolled in regular classes at a public elementary school. In both groups, multiple logistic regression analysis was performed using the results of MOGRAZ, age, and sex as parameters, and algorithms for a predictive diagnostic model of AD/HD were created. RESULTS: The area under the receiver operating characteristic curve (ROC-AUC) between the predominantly inattentive type AD/HD subgroup and non-AD/HD group was 0.884 (95% confidence interval: 0.837-0.932), and the ROC-AUC between the combined type AD/HD subgroup and non-AD/HD group was 0.914 (95% CI: 0.869-0.959). CONCLUSION: The prediction model using the MOGRAZ score allowed us to create an objectivity index to determine the diagnosis of AD/HD that can be easily used in clinical practice. We plan additional verification of this prediction model with additional participants.

Pressure dependence of transverse acoustic phonon energy in ferropericlase across the spin transition.

We investigated transverse acoustic (TA) phonons in iron-bearing magnesium oxide (ferropericlase) up to 56 GPa using inelastic x-ray scattering (IXS). The results show that the energy of the TA phonon far from the Brillouin zone center suddenly increases with increasing pressure above the spin transition pressure of ferropericlase. Ab initio calculations revealed that the TA phonon energy far from the Brillouin zone center is higher in the low-spin state than in the high spin state; that the TA phonon energy depend weakly on pressure; and that the energy gap between the TA and the lowest-energy-optic phonons is much narrower in the low-spin state than in the high-spin state. This allows us to conclude that the anomalous behavior of the TA mode in the present experiments is the result of gap narrowing due to the spin transition and explains contradictory results in previous experimental studies.

Pressure-induced change of the electronic state in the tetragonal phase of CaFe2As2.

We have investigated the electronic states of single-crystal CaFe2As2 under hydrostatic pressure using (57)Fe Mössbauer spectroscopy and magnetization measurements. The center shift and the quadrupole splitting were refined from observed (57)Fe Mössbauer spectra using the single-crystalline sample under pressure at room temperature. A discontinuous decrease in the pressure dependence of the refined center shift was observed at 0.33 GPa without any anomaly in the pressure dependence of the refined quadrupole splitting, indicating a purely electronic state change in CaFe2As2 with a tetragonal structure. Such a change is shown to be reflected in the peak-like anomalies observed in the pressure dependences of the magnetic susceptibility at 0.26 GPa above 150 K. Our results reveal that this pressure-induced electronic state change suppresses the tetragonal-to-orthorhombic structural phase transition accompanied by an antiferromagnetic ordering. We further observed superconductivity in CaFe2As2 below ∼ 8 K around 0.33 GPa although our sample was not in a single phase at this pressure. These findings suggest that the electronic state change observed in CaFe2As2 with the tetragonal structure is relevant to the appearance of the pressure-induced superconductivity in AFe2As2.

Note: Improved sensitivity of magnetic measurements under high pressure in miniature ceramic anvil cell for a commercial SQUID magnetometer.

Two modifications have been made to a miniature ceramic anvil high pressure cell (mCAC) designed for magnetic measurements at pressures up to 12.6 GPa in a commercial superconducting quantum interference (SQUID) magnetometer [N. Tateiwa et al., Rev. Sci. Instrum. 82, 053906 (2011); ibid. 83, 053906 (2012)]. Replacing the Cu-Be piston in the former mCAC with a composite piston composed of the Cu-Be and ceramic cylinders reduces the background magnetization significantly smaller at low temperatures, enabling more precise magnetic measurements at low temperatures. A second modification to the mCAC is the utilization of a ceramic anvil with a hollow in the center of the culet surface. High pressures up to 5 GPa were generated with the "cupped ceramic anvil" with the culet size of 1.0 mm.

Observation of a pressure-induced As-As hybridization associated with a change in the electronic state of Fe in the tetragonal phase of EuFe2As2.

The electronic and vibrational properties of EuFe(2)As(2) in the tetragonal phase between 0 and 5 GPa have been investigated using (57)Fe Mössbauer spectroscopy and (57)Fe nuclear resonance inelastic scattering, respectively. We find a discontinuous increase of the center shift around 2.3 GPa, reflecting a change of the electronic state of Fe, and above 2.5 GPa a softening of the optical phonon modes associated with an increase of the relative volume of the FeAs(4) tetrahedron in the unit cell. Our findings reveal that an effective As-As hybridization along the c axis appears at approximately 2.3 GPa in the tetragonal phase of EuFe(2)As(2), along with a change in the electronic state of Fe, causing bulk superconductivity to appear at a low temperature. Consequently, the change in the electronic state of the Fe atom and the effective As-As hybridization play key roles in the pressure-induced superconductivity in the tetragonal phase of AFe(2)As(2).

Evaluation of neutron dosimetry on pancreatic cancer phantom model for application of intraoperative boron neutron-capture therapy.

Pancreatic cancer is one of the most difficult neoplasms to cure and there is a need for new combinated therapy. If sufficient boron compound can be targeted accurate to the tumour, Boron Neutron-Capture Therapy (BNCT) can be applied to pancreatic cancer. We administrated BNCT to a cancer with pancreatic cancer patient using intraoperative irradiation. In this study, we performed preliminary dosimetry of a phantom model of the abdominal cavity. The flux of 8>x10(7)n/cm(2)/s (0.1 ratio) was 4.5 cm in depth from the surface in the case of simple irradiation, and the field of thermal neutrons was spread as 13 cm and 11.5 cm were usage of Void and Void with LiF collimation, respectively in thermal (OO-0011) mode. In the case of epithermal (CO-0000) mode, epithermal and fast components are four times higher at the surface level. In the case of mixed beam (OO-0000) mode, thermal neutron flux was the same as thermal neutron mode at a depth of 10 cm, but the gamma-ray component was two times higher than that of thermal neutron mode. With the use of Void and LiF collimation, thermal neutrons were selectively applied to the tumour combined with the CT-imaging of the cancer patient. This means that we could irradiate the tumour selectively and safely as possible, reducing the effects on neighboring healthy tissues. High resolution whole body dosimetry will be necessary to extend the application of BNCT to pancreatic cancer.

Development of the sexual skin with pubertal maturation in female chimpanzees.

We examined the adolescent development of the sexual skin of chimpanzees (Pan troglodytes) by daily observation, evaluation of swelling, and weekly photogrametry. Although the size of swelling differed with the individual, the development of sexual swelling followed four stages: (1) initial stage, the labial region began to show a slight swelling and recovery; (2) labial stage, swelling at the labial region became maximal; (3) anal stage, another swelling center appeared in the anal region and enlarged; and (4) full maturity stage, the labial and anal regions merged into a full swelling. Menarche occurred after the beginning of the anal stage, and the regular cycle was then established. All of the swelling stages and the peak swelling size are regarded as good indicators of reproductive maturation in chimpanzees.

Identification of a protanomalous chimpanzee by molecular genetic and electroretinogram analyses.

We determined the structures of long (L)-wavelength-sensitive and middle (M)-wavelength-sensitive opsin gene array of 58 male chimpanzees and we investigated relative sensitivity to red and green lights by electroretinogram flicker photometry. One subject had protanomalous color vision, while others had normal color vision. Unlike in humans, a polymorphic difference in the copy number of the genes and a polymorphic base substitution at amino acid position 180 were not frequently observed in chimpanzees.

Phonon density of states and compression behavior in iron sulfide under pressure.

We report the partial phonon densities of states (DOS) of iron sulfide, a possible component of the rocky planet's core, measured by the 57Fe nuclear resonant inelastic x-ray scattering and calculate the total phonon DOS under pressure. From the phonon DOS, we drive thermodynamic parameters. A comparison of the observed and estimated compressibilities makes it clear that there is a large pure electronic contribution in the observed compressibility in the metallic state. Our results present the observation of thermodynamic parameters of iron sulfide with the low-spin state of an Fe2+ ion at the high density, which is similar to the condition of the Martian core.

Intracellular targeting of sodium mercaptoundecahydrododecaborate (BSH) to solid tumors by transferrin-PEG liposomes, for boron neutron-capture therapy (BNCT).

The successful treatment of cancer by boron neutron-capture therapy (BNCT) requires the selective delivery of relatively high concentration of 10B compounds to malignant tumor tissue. This study focuses on a new tumor-targeting drug delivery system for BNCT that uses small (less than 200 nm in diameter), unilamellar mercaptoundecahydrododecaborate (BSH)-encapsulating, transferrin (TF)-conjugated polyethyleneglycol liposomes (TF-PEG liposomes). When TF-PEG liposomes were injected at a dose of 35 mg 10B/kg, we observed a prolonged residence time in the circulation and low uptake by the reticuloendothelial system (RES) in Colon 26 tumor-bearing mice, resulting in enhanced accumulation of 10B into the solid tumor tissue (e.g., 35.5 microg/g). TF-PEG liposomes maintained a high 10B level in the tumor, with concentrations over 30 microg/g for at least 72 h after injection. This high retention of 10B in tumor tissue indicates that binding and concomitant cellular uptake of the extravasated TF-PEG liposomes occurs by TF receptor and receptor-mediated endocytosis, respectively. On the other hand, the plasma level of 10B decreased, resulting in a tumor/plasma ratio of 6.0 at 72 h after injection. Therefore, 72 h after injection of TF-PEG liposomes was selected as the time point of BNCT treatment. Administration of BSH encapsulated in TF-PEG liposomes at a dose of 5 or 20 mg 10B/kg and irradiation with 2 x 10(12) neutrons/cm2 for 37 min produced tumor growth suppression and improved long-term survival compared with PEG liposomes, bare liposomes and free BSH. Thus, intravenous injection of TF-PEG liposomes can increase the tumor retention of 10B atoms, which were introduced by receptor-mediated endocytosis of liposomes after binding, causing tumor growth suppression in vivo upon thermal neutron irradiation. These results suggest that BSH-encapsulating TF-PEG liposomes may be useful as a new intracellular targeting carrier in BNCT therapy for cancer.

Extended study for performances of beam quality indicator.

The performance of the beam quality indicator (BQI) was studied for confirmation of its reliability. An original BQI (named "BQI.org") and five newly designed BQIs (named "BQI.001-BQI.005") were compared with a variety of imaging systems with different beam spectra. With the best quality of a BQI image obtained, the data was carefully analyzed, and +/-1% precision was expected. However, a +/-7% systematic uncertainty was observed for imaging systems, including a difference of BQIs. Spectra of attenuation coefficients were measured using a TOF method for Pb and Ti, which was used to define a calibration curve for the BQIs. The curve will be compared with the previously defined calibration curve for the BQI.org.

Performance comparison of neutron and X-ray sensitive photo-stimulated imaging plates.

Statistical characteristics of photo-stimulated luminescent (PSL) signals are studied using thermal neutrons, X- and gamma-rays. It is shown that the statistical fluctuation of PSL is described simply by the PSL value itself and is independent of radiation type, except for short-range high-LET particles. However, it is expected that the spatial resolution should be affected if the range of electrons or secondaries were much longer than the instrumental resolution (pixel size). When output PSL signals are compared between X- and gamma-rays, the PSL values were proportional to the exposed air dose, independent of X-ray energy. However, signals from 60Co gamma-rays were approximately 1% of 22-40 kV X-ray output at the same dose.

Accumulation of boron compounds to tumor with polyethylene-glycol binding liposome by using neutron capture autoradiography.

The cytotoxic effect of boron neutron capture therapy (BNCT) is due to a nuclear reaction between 10B and thermal neutrons. It is necessary to accumulate the 10B atoms to the tumor cells selectively for effective BNCT. In order to achieve an accurate measurement of 10B concentrations in the biological samples, we employed a technique of neutron capture autoradiography (NCAR) of the sliced whole-body samples of tumor bearing mice using CR-39 plastic track detectors. The CR-39 detectors attached with samples were exposed to thermal neutrons in the thermal column of the TRIGA II reactor at the Institute for Atomic Energy, Rikkyo University and thermal neutron facility of Paul Scherer Institute(PSI). We obtained NCAR images for mice injected intravenously by 10B-PEG liposome, 10B-transferrin-PEG liposome, or 10B-bare liposome. The 10B concentrations in the tumor tissue of mice were estimated by means of alpha-track density measurements. In this study, we can increase the accumulation of 10B atoms in the tumor tissues by binding polyethylene-glycol chains to the surface of liposome, which increase the retention in the blood flow and escape the phagocytosis by reticulo-endothelial systems. Therefore, we will be able to apply NCAR technique for selection of effective 10B carrier in BNCT for cancer.

Sonographic evaluation of the anterior liver surface in chronic liver diseases using a 7.5-MHz annular-array transducer: correlation with laparoscopic and histopathologic findings.

PURPOSE: We studied the sonographic appearance of the anterior liver surface using an ultrasound scanner equipped with a 7.5-MHz annular-array transducer to determine the accuracy of this imaging modality in monitoring the course of chronic liver diseases. METHODS: We prospectively evaluated patterns of the liver surface in the sonograms of 77 consecutive patients with chronic liver diseases who had undergone sonographic examination with a 7.5-MHz annular-array transducer and a 3.75-MHz convex-array transducer over a 2-year period and compared these findings with those of laparoscopy (using previously described categories) and histopathology. RESULTS: Histopathologically confirmed disease prevalences for inactive chronic hepatitis, active chronic hepatitis, liver cirrhosis, and others were 10% (8/77), 56% (43/77), 29% (22/77), and 5% (4/77), respectively. The sonographic appearance of the liver surface with the 3.75-MHz transducer was classified as either a regular or an irregular pattern. The regular pattern corresponded to 69% (34/50) of the cases in laparoscopic category 200 or 300 and the irregular pattern with 85% (23/27) of the cases in category 400 or 500. The sonographic appearance of the liver surface with the 7.5-MHz transducer was classified as regular, unevenly irregular, diffusely irregular, or nodular. These 4 patterns detected 75% (24/32), 78% (14/18), 52% (12/23), and 75% (3/4) of the cases of laparoscopic categories 200, 300, 400, and 500, respectively. In a comparison of the sonographic patterns of the liver surface with the differential histopathologic findings, the regular sonographic pattern corresponded to 88% (7/8) of the cases of inactive chronic hepatitis, the unevenly irregular pattern with 35% (15/43) of the cases of active chronic hepatitis, and the diffusely irregular and nodular patterns (considered as 1 group) with 68% (15/22) of the cases of liver cirrhosis. CONCLUSIONS: Our results suggest that sonographic evaluation of the liver surface with a 7.5-MHz annular-array transducer using this classification provides detailed information on the evolution of chronic liver diseases that correlates with the laparoscopic and histopathologic findings and thus is a useful noninvasive method for monitoring the disease course to cirrhosis.

Metamorphosis-dependent transcriptional regulation of xak-c, a novel Xenopus type I keratin gene.

Anuran larvae transform their epidermis to the adult counterpart during metamorphosis. The major event of this process is the proliferation of larval epidermal basal cells and their differentiation into adult ones. The present study isolated novel type I keratin cDNA dubbed xak-c (Xenopus adult keratin-c) that was exclusively expressed in adult epidermal basal cells. The gene started its expression in the larval epidermis at the onset of metamorphosis. Thyroid hormone (TH) induced the precocious expression of the gene in the epidermis of premetamorphic tadpoles. To study the transcriptional regulation of this gene in relation to epidermal metamorphosis, a 2.8 kb 5'-flanking region of xak-c was cloned and its promoter activity was investigated. Gene constructs were made so as to contain the xak-c promoter region and gene of EGFP or luciferase as a reporter gene and were transfected into various types of cells, which revealed that the 5'-flanking region had an epidermal cell-specific transcriptional activity in both anurans and mammals. Larval skin tissues of Xenopus were transfected with the constructs and cultured in the presence and absence of TH, which showed that the promoter region is responsive to TH, although the region did not contain the consensus TH response element-like sequence. In sharp contrast, the promoter region did not respond to TH in the adult skin, clearly indicating that the cloned region contains specific sequences that respond to metamorphosis-dependent transcription factor(s).