Giant Magnetoresistance Effect in the Metal-Insulator Transition of Pyrochlore Oxide Nd2Ir2O7

We investigated the magnetoresistance (MR) effect of the pyrochlore oxide Nd2Ir2O7, which shows a metal-insulator transition at T_MI =33 K. A small positive MR effect was observed in the metallic state above T_MI, while a large negative MR effect was observed in the insulating state below T_MI . MR effects exceeding 3000% were found at 1 K at a field of 9 T. As a result, we confirmed the crossover from the insulating state to a state with a small or partial band gap in a field up to 56 T. Furthermore, from the MR effect in Eu2Ir2O7 (T_MI = 120 K) and Gd$_2$Ir$_2$O$_7$ (T_MI = 127 K), we revealed that the large negative MR effect of the pyrochlore iridate Ln2Ir2O7 depends on the magnetism of the lanthanide Ln^{3+} ion. The d-f interaction plays a significant role in the large negative MR effect in the insulating state.Comment: 10 pages, 4 figure

Metal–Insulator Transitions in Pyrochlore Oxides Ln2Ir2O7

We report the physical properties of Ln2Ir2O7 (Ln = Nd, Sm, Eu, Gd, Tb, Dy, and Ho), which exhibit metal-insulator transitions (MITs) at different temperatures. The transition temperature TMI increases with a reduction in the ionic radius of Ln. The ionic radius　boundary for MITs in Ln2Ir2O7 lies between Ln = Pr and Nd. MITs in Ln2Ir2O7 have some common features. They are second-order transitions. Under the field cool condition, a weak ferromagnetic component (»10−3 μB/f.u.) caused by Ir 5d electrons is observed below TMI.The entropy associated with MITs for Ln = Nd, Sm, and Eu is estimated to be 0.47, 2.0, and 1.4 J/K mole, respectively. The change in entropy is much smaller than 2R ln 2 [11.5 J /K mole] expected in a magnetic transition due to localized moments of S = 1/2. The feature of continuous MITs in Ln2Ir2O7 is discussed

"Control of residual stress in thin films by substrate vibration and their mechanical property"

"The prevention of residual stress of thin film syntheses is very important in processing engineering surfaces. In this paper, details of residual stress control by thevibration of the substrate using PZT at voltage of 0-100 V are presented. The thin films deposited are crystalline TiN, Ti, Cu, Al films and amorphous C, Si films. The residual stresses are measured using Stoney's method. The results of our experiment show that for Ti, TiN and Cu thin films, compressive stresses are changed to tensile stresses. XRD and Auger spectroscopy results verify that the composition and crystalline structure of the treated and untreated crystalline thin films to be the same. But it is shown that the grain size in the film tend to decrease with increasing vibration amplitude. From the change of the microstructure of the film, a model for the control of residual stress is proposed. The change of adhesion strength is measured by a pin-on-disk tribo-tester with variation of the residual stress. The adhesion strength shows the maximum value at near zero residual stress. Therefore, control of residual stress by substrate vibration is shown to be an effective method for improving the wear life.

Metal–Insulator Transitions in Pyrochlore Oxides Ln2Ir2O7

We report the physical properties of Ln2Ir2O7 (Ln = Nd, Sm, Eu, Gd, Tb, Dy, and Ho), which exhibit metal-insulator transitions (MITs) at different temperatures. The transition temperature TMI increases with a reduction in the ionic radius of Ln. The ionic radius　boundary for MITs in Ln2Ir2O7 lies between Ln = Pr and Nd. MITs in Ln2Ir2O7 have some common features. They are second-order transitions. Under the field cool condition, a weak ferromagnetic component (»10−3 μB/f.u.) caused by Ir 5d electrons is observed below TMI. The entropy associated with MITs for Ln = Nd, Sm, and Eu is estimated to be 0.47, 2.0, and 1.4 J/K mole, respectively. The change in entropy is much smaller than 2R ln 2 [11.5 J /K mole] expected in a magnetic transition due to localized moments of S = 1/2. The feature of continuous MITs in Ln2Ir2O7 is discussed

Primary Colonic Signet Ring Cell Carcinoma Presenting Carcinocythemia: An Autopsy Case

Primary colorectal signet ring cell carcinoma (SRCC) is a rare but distinctive type of mucin-producing adenocarcinoma of the large intestine with still controversial clinicopathological features and prognosis. We encountered primary colonic SRCC in a 51-year-old Japanese man with extensive bone metastasis ultimately leading to carcinocythemia before the initiation of chemotherapy and surgical intervention. Three days before death, besides progressive disseminated intravascular coagulation that had been present on admission, hematological examination showed sudden leukocytosis with nonhematopoietic cells that subsequently turned out to be signet ring cells (SRCs). Carcinocythemia, the presence of circulating cancer cells in peripheral blood, is considered to be a rare but an ominous phenomenon occurring in the advanced stage of certain types of cancers, particularly mammary lobular carcinoma. It can be assumed that carcinoma cells lacking intercellular cohesiveness and polarized cell membrane organization, including SRCs as well as lobular carcinoma cells, can readily get access to the peripheral circulation; however, to our knowledge, this is the first report of primary colorectal SRCC that presented carcinocythemia. Extensive bone metastatic sites, in the present case, may have functioned as a reservoir of circulating SRCs

Histological Observation of the Development of Follicles and Follicular Atresia in Immature Rat Ovaries

To clarify the development of follicular growth and atresia in the immature ovary, rats. ovaries and blood were removed at fixed points during the period from 0 to 35 days after birth (Day 0 to Day 35). The ovaries were immunohistochemically examined, and blood concentrations of serum follicle-stimulating hormone (FSH) and estrogen (E) were measured. We investigated how time-course changes in follicular cell proliferation, estrogen receptor β (ERβ), apoptosis, and FSH and E concentrations are connected with follicular growth and atresia. Apoptosis was found in the ova from Day 0 to Day 3. On Day 15, apoptosis occurred in some granulosa cell nuclei in some follicles, but BrdU uptake and the presence of cyclin D2 and ER β could be observed in other granulosa cells. From Day 17, apoptosis increased in the follicular granulosa cells, and BrdU uptake and the presence of cyclin D2 and ERβ were decreased. Follicular atresia continued, reaching a peak on Day 30. Serum FSH and E concentrations increased until Day 15, then markedly decreased after Day 17. The mechanism of apoptosis in the ova from Day 0 to 3 has not been clarified. However, the onset of follicular atresia was caused by apoptotic degeneration from Days 15 to 17. These results showed that the oocytes were selected by apoptosis at 2 points in the time-course of the maturation of the ovary

Cognitive Profile of Idiopathic Normal Pressure Hydrocephalus

Background/Aims: Frontal lobe dysfunction is believed to be a primary cognitive symptom in idiopathic normal pressure hydrocephalus (iNPH); however, the neuropsychology of this disorder remains to be fully investigated. The objective of this study was to delineate a comprehensive profile of cognitive dysfunction in iNPH and evaluate the effects of cerebrospinal fluid (CSF) shunt surgery on cognitive dysfunction. Methods: A total of 32 iNPH patients underwent neuropsychological testing of memory, attention, language, executive function, and visuoperceptual and visuospatial abilities. Of these 32 patients, 26 were reevaluated approximately 1 year following CSF shunt surgery. The same battery of tests was performed on 32 patients with Alzheimer’s disease (AD) and 30 healthy elderly controls. Results: The iNPH patients displayed baseline deficits in attention, executive function, memory, and visuoperceptual and visuospatial functions. Impairments of attention, executive function, and visuoperceptual and visuospatial abilities in iNPH patients were more severe than in those with AD, whereas the degree of memory impairment was comparable to that in AD patients. A significant improvement in executive function was observed following shunt surgery. Conclusion: Patients with iNPH are impaired in various aspects of cognition involving both ‘frontal’ executive functions and ‘posterior cortical’ functions. Shunt treatment can ameliorate executive dysfunction

Study of interleukin-6 in the spread of colorectal cancer: the diagnostic significance of IL-6.

We investigated the diagnostic significance of IL-6 for lymph node metastasis and/or hepatic metastasis from colorectal cancer in 65 patients and evaluated the contributions of 8 factors (IL-6, HGF, IL-1beta, TNF-alpha, TGF-beta1, ELAM-1, ICAM-1, VCAM-1) toward Dukes.s classification of 53 patients. We also examined IL-6 expression in tumor tissue. From the receiver operating characteristic (ROC) curve analysis, an optimal cutoff value of 5.8 pg/ml was determined to classify lymph node and/or hepatic metastasis, and that of 6.3 pg/ml was determined to classify hepatic metastasis. These values indicated sensitivities of 55.0% and 71.4%, and specifi cities of 100% and 88.6%, respectively. IL-6, HGF, and ELAM-1 were very useful for distinguishing among Dukes.s A/B group, C group, and D group. In all cases with high IL-6 values (more than 25.0 pg/ml), immunohistochemical staining was positive for IL-6 in the cytoplasm of cancer cells. IL-6 is strongly suspected to be involved in lymph node and/or hepatic metastasis by promoting it through HGF, and serum IL-6 value (pg/ml) would be useful diagnostically to estimate whether or not there is a high risk of lymph node and/or hepatic metastasis