49 research outputs found
Quantum Phase Transition in the Itinerant Antiferromagnet (V0.9Ti0.1)2O3
Quantum-critical behavior of the itinerant electron antiferromagnet
(V0.9Ti0.1)2O3 has been studied by single-crystal neutron scattering. By
directly observing antiferromagnetic spin fluctuations in the paramagnetic
phase, we have shown that the characteristic energy depends on temperature as
c_1 + c_2 T^{3/2}, where c_1 and c_2 are constants. This T^{3/2} dependence
demonstrates that the present strongly correlated d-electron antiferromagnet
clearly shows the criticality of the spin-density-wave quantum phase transition
in three space dimensions.Comment: 4 pages, 4 figure
Wide dynamic range charge sensor operation by high-speed feedback control of radio-frequency reflectometry
Semiconductor quantum dots are useful for controlling and observing quantum
states and can also be used as sensors for reading out quantum bits and
exploring local electronic states in nanostructures. However, challenges remain
for the sensor applications, such as the trade-off between sensitivity and
dynamic range and the issue of instability due to external disturbances. In
this study, we demonstrate proportional-integral-differential feedback control
of the radio-frequency reflectometry in GaN nanodevices using a
field-programmable gate array. This technique can maintain the operating point
of the charge sensor with high sensitivity. The system also realizes a wide
dynamic range and high sensor sensitivity through the monitoring of the
feedback signal. This method has potential applications in exploring dynamics
and instability of electronic and quantum states in nanostructures.Comment: 13 pages, 5 figure
Distinct and Essential Roles of Transcription Factors IRF-3 and IRF-7 in Response to Viruses for IFN-α/β Gene Induction
AbstractInduction of the interferon (IFN)-α/β gene transcription in virus-infected cells is an event central to innate immunity. Mice lacking the transcription factor IRF-3 are more vulnerable to virus infection. In embryonic fibroblasts, virus-induced IFN-α/β gene expression levels are reduced and the spectrum of the IFN-α mRNA subspecies altered. Furthermore, cells additionally defective in IRF-7 expression totally fail to induce these genes in response to infections by any of the virus types tested. In these cells, a normal profile of IFN-α/β mRNA induction can be achieved by coexpressing both IRF-3 and IRF-7. These results demonstrate the essential and distinct roles of the two factors, which together ensure the transcriptional efficiency and diversity of IFN-α/β genes for the antiviral response
Nonlinear magnetic susceptibility and aging phenomena in reentrant ferromagnet: CuCoCl-FeCl graphite bi-intercalation compound
Linear and nonlinear dynamic properties of a reentrant ferromagnet
CuCoCl-FeCl graphite bi-intercalation compound are
studied using AC and DC magnetic susceptibility. This compound undergoes
successive phase transitions at the transition temperatures (= 16 K),
(= 9.7 K), and (= 3.5 K). The static and dynamic behaviors of
the reentrant spin glass phase below are characterized by those of
normal spin glass phase with critical exponent = 0.57 0.10, a
dynamic critical exponent = 8.5 1.8, and an exponent (= 1.55
0.13) for the de Almeida -Thouless line. A prominent nonlinear
susceptibility is observed between and and around ,
suggesting a chaotic nature of the ferromagnetic phase () and the helical spin ordered phase (). The
aging phenomena are observed both in the RSG and FM phases, with the same
qualitative features as in normal spin glasses. The aging of zero-field cooled
magnetization indicates a drastic change of relaxation mechanism below and
above . The time dependence of the absorption
is described by a power law form () in the
ferromagnetic phase, where at =
0.05 Hz and = 7 K. No -scaling law for
[] is observed.Comment: 14 pages, 16 figures, and 2 table
イガン ジュツゴ ニ チョクチョウ テンイ オ キタシタ 1レイ
We report a case of rectal metastasis from gastric cancer. The patient was a 69-year-old man with diarrhea as his major symptoms, who underwent a distal gastrostomy for gastric cancer 2 years previously. We suspected primary or metastatic rectal cancer from colonoscopic examination and barium enema. A lower anterior resection was performed. Postoperative historical examination identified poorly differentiated adenocarcinoma and signet cell carcinoma identical to the gastric cancer. Finally the lesion was diagnosed as metastatic rectal cancer from gastric cancer that showed same pattern in PAS stain. There were only 40 cases in reports in the literature from 2002 to 2012, to our knowledge. We report a rare case
ジュツゼン シンダン ガ コンナン ダッタ フクジン シュッケツ ノ 1レイ
A 73-year-old man was admitted to the hospital because of a growing tumor in his left upper abdomen. The tumor was peripherally enhanced and filled with necrotic tissue by contrast CT. By PET-CT, SUV max was high in the peripheral area of the tumor. Endocrinogical data for adrenal function were within the normal range. Accordingly, we diagnosed a nonfunctional adrenal tumor. Left adrenalectomy was performed, because a possibility of malignant tumor could not be ruled out and abdominal tumor was growing fast for a few months. At laparotomy, we saw the dorsal displacement of the transverse colon by a giant cystic tumor, which has several septums and was filled with old bloody fluid components. The resected tumor was 15cm in maximum diameter and 860g in weight. Histopathological diagnosis was adrenal hemorrhage without malignant findings
Severe neurological phenotypes of Q129 DRPLA transgenic mice serendipitously created by en masse expansion of CAG repeats in Q76 DRPLA mice
We herein provide a thorough description of new transgenic mouse models for dentatorubral–pallidoluysian atrophy (DRPLA) harboring a single copy of the full-length human mutant DRPLA gene with 76 and 129 CAG repeats. The Q129 mouse line was unexpectedly obtained by en masse expansion based on the somatic instability of 76 CAG repeats in vivo. The mRNA expression levels of both Q76 and Q129 transgenes were each 80% of that of the endogenous mouse gene, whereas only the Q129 mice exhibited devastating progressive neurological phenotypes similar to those of juvenile-onset DRPLA patients. Electrophysiological studies of the Q129 mice demonstrated age-dependent and region-specific presynaptic dysfunction in the globus pallidus and cerebellum. Progressive shrinkage of distal dendrites of Purkinje cells and decreased currents through α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid and γ-aminobutyrate type A receptors in CA1 neurons were also observed. Neuropathological studies of the Q129 mice revealed progressive brain atrophy, but no obvious neuronal loss, associated with massive neuronal intranuclear accumulation (NIA) of mutant proteins with expanded polyglutamine stretches starting on postnatal day 4, whereas NIA in the Q76 mice appeared later with regional specificity to the vulnerable regions of DRPLA. Expression profile analyses demonstrated age-dependent down-regulation of genes, including those relevant to synaptic functions and CREB-dependent genes. These results suggest that neuronal dysfunction without neuronal death is the essential pathophysiologic process and that the age-dependent NIA is associated with nuclear dysfunction including transcriptional dysregulations. Thus, our Q129 mice should be highly valuable for investigating the mechanisms of disease pathogenesis and therapeutic interventions