A Note on Stable States of Dipolar Systems at Low Temperatures

In the past several years, many important innovations in nanotechnology were made. Today it becomes possible to make nanosize magnetic particles, and development of high storage-density magnetic device is desired. In such a magnetic particle system, dipole interaction plays the main role. In this note, we consider stable states of dipolar systems at low temperature: Some systems show ``antiferromagnetic structure'', and others show magnetic domain structure, depending on lattice shapes.Comment: 5 pages including 5 eps figures, to appear in "Computer Simulation Studies in Condensed Matter Physics XVIII", Eds. D. P. Landau, S. P. Lewis, and H.-B. Sch\"{u}ttler (Springer Verlag, Heidelberg, Berlin

Finite dipolar hexagonal columns on piled layers of triangular lattice

We have investigated, by the Monte Carlo simulation, spin systems which represent moments of arrayed magnetic nanoparticles interacting with each other only by the dipole-dipole interaction. In the present paper we aim the understanding of finite size effects on the magnetic nanoparticles arrayed in hexagonal columns cut out from the close-packing structures or from those with uniaxial compression. In columns with the genuine close-packing structures, we observe a single vortex state which is also observed previously in finite 2-dimensional systems. On the other hand in the system with the inter-layer distance set $1/\sqrt{2}$ times of the close-packing one, we found ground states which depend on the number of layers. The dependence is induced by a finite size effect and is related to a orientation transition in the corresponding bulk system.Comment: 3 pages, 2 figures. Proceedings of the International Conference on Magnetism 2006 (ICM2006) conference. To appear in a special volume of Journal of Magnetism and Magnetic Material

Positive Autoregulation Delays the Expression Phase of Mammalian Clock Gene Per2

In mammals, cellular circadian rhythms are generated by a transcriptional-translational autoregulatory network that consists of clock genes that encode transcriptional regulators. Of these clock genes, Period1 (Per1) and Period2 (Per2) are essential for sustainable circadian rhythmicity and photic entrainment. Intriguingly, Per1 and Per2 mRNAs exhibit circadian oscillations with a 4-hour phase difference, but they are similarly transactivated by CLOCK-BMAL1. In this study, we investigated the mechanism underlying the phase difference between Per1 and Per2 through a combination of mathematical simulations and molecular experiments. Mathematical analyses of a model for the mammalian circadian oscillator demonstrated that the slow synthesis and fast degradation of mRNA tend to advance the oscillation phase of mRNA expression. However, the phase difference between Per1 and Per2 was not reproduced by the model, which implemented a 1.1-fold difference in degradation rates and a 3-fold difference in CLOCK-BMAL1 mediated inductions of Per1 and Per2 as estimated in cultured mammalian cells. Thus, we hypothesized the existence of a novel transcriptional activation of Per2 by PER1/2 such that the Per2 oscillation phase was delayed. Indeed, only the Per2 promoter, but not Per1, was strongly induced by both PER1 and PER2 in the presence of CLOCK-BMAL1 in a luciferase reporter assay. Moreover, a 3-hour advance was observed in the transcriptional oscillation of the delta-Per2 reporter gene lacking cis-elements required for the induction by PER1/2. These results indicate that the Per2 positive feedback regulation is a significant factor responsible for generating the phase difference between Per1 and Per2 gene expression

Overexpression of TEAD4 in atypical teratoid/rhabdoid tumor: New insight to the pathophysiology of an aggressive brain tumor

BackgroundAtypical teratoid/rhabdoid tumor (AT/RT) is a highly malignant embryonal brain tumor that occurs mainly in early childhood. Although most of the tumors are characterized by inactivating mutations of the tumor suppressor gene, SMARCB1, the biological basis of its tumorigenesis and aggressiveness is still unknown.ProcedureWe performed high‐throughput copy number variation analysis of primary cell lines generated from primary and relapsed tumors from one of our patients to identify new genes involved in AT/RT biology. The expression of the identified gene was validated in 29 AT/RT samples by gene expression profiling, quantitative real‐time polymerase chain reaction, and immunohistochemistry (IHC). Furthermore, we investigated the function of this gene by mutating it in rhabdoid tumor cells.ResultsTEAD4 amplification was detected in the primary cell lines and its overexpression was confirmed at mRNA and protein levels in an independent cohort of AT/RT samples. TEAD4’s co‐activator, YAP1, and the downstream targets, MYC and CCND1, were also found to be upregulated in AT/RT when compared to medulloblastoma. IHC showed TEAD4 and YAP1 overexpression in all samples. Cell proliferation and migration were significantly reduced in TEAD4‐mutated cells.ConclusionsWe report the overexpression of TEAD4 in AT/RT, which is a key component of Hippo pathway. Recent reports revealed that dysregulation of the Hippo pathway is implicated in tumorigenesis and poor prognosis of several human cancers. Our results suggest that TEAD4 plays a role in the pathophysiology of AT/RT, which represents a new insight into the biology of this aggressive tumor.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/137309/1/pbc26398_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/137309/2/pbc26398.pd

An unexplored role of the CrOx shell in an elaborated Rh/CrOx core–shell cocatalyst for photocatalytic water splitting: a selective electron transport pathway from semiconductors to core metals, boosting charge separation and H₂ evolution

A core–shell structured Rh/CrOx cocatalyst has endowed various semiconductors with high efficiency in water-splitting photocatalysis, where thin CrOx layers on Rh have been assumed to be physical blockers of O₂ to the metal surface to suppress unfavorable reverse reactions (e.g., catalytic H₂O formation from H₂ and O₂). Herein, we propose another unexplored but favorable function of CrOx layers: a selective electron transport pathway from photocatalysts to the Rh core boosting charge separation and H₂ production. The subsequent loading of CrOx layers onto Rh increased the rate of visible light H₂ evolution of a Bi₄NbO₈Cl photocatalyst, even in a half reaction with a hole scavenger where O₂ does not evolve. Transient absorption spectroscopy revealed that the CrOx layer increases the electron path from Bi₄NbO₈Cl to Rh. Importantly, the highest H₂-evolution activity was obtained by simultaneous photodeposition using CrIII and RhIII precursors, which had not yet been examined. In this sample, Rh nanoparticles were enclosed by an amorphous CrOx shell, where Rh particles were less directly attached to the semiconductor. Therein, CrOx inserted between Bi₄NbO₈Cl and Rh effectively suppresses undesirable hole transfer from Bi₄NbO₈Cl to Rh, while such hole transfer partially occurs when they are in direct contact. These results indicated that CrOx functions as a selective electron transport pathway and improves the H₂ evolution activity. Although the development strategy of cocatalysts has so far focused on surface redox reactions, this study offers a new approach for the design of highly efficient cocatalysts based on the carrier transfer process, especially at semiconductor–cocatalyst interfaces

Manipulation of charge carrier flow in Bi₄NbO₈Cl nanoplate photocatalyst with metal loading

Separation of photoexcited charge carriers in semiconductors is important for efficient solar energy conversion and yet the control strategies and underlying mechanisms are not fully established. Although layered compounds have been widely studied as photocatalysts, spatial separation between oxidation and reduction reaction sites is a challenging issue due to the parallel flow of photoexcited carriers along the layers. Here we demonstrate orthogonal carrier flow in layered Bi₄NbO₈Cl by depositing a Rh cocatalyst at the edges of nanoplates, resulting in spatial charge separation and significant enhancement of the photocatalytic activity. Combined experimental and theoretical studies revealed that lighter photogenerated electrons, due to a greater in-plane dispersion of the conduction band (vs. valence band), can travel along the plane and are readily trapped by the cocatalyst, whereas the remaining holes hop perpendicular to the plane because of the anisotropic crystal geometry. Our results propose manipulating carrier flow via cocatalyst deposition to achieve desirable carrier dynamics for photocatalytic reactions in layered compounds

Dynamics of rheumatoid joint

In the present communication the recent works done by the Rheumatism Research Group of Department of Orthopedic Surgery, Okayama University, are described. The principal findings may briefly be summarized as follows. 1. Pathohistological pictures of the synovial membrane are classified into six types. Among them, Fibrinoid type and Follicular-Fibrosis type are the representative ones of chronic rheumatoid arthritis. 2. For the evaluation of the systemic as well as the local activities in rheumatoid arthritis and for judging the therapeutic effect, some indices have been established. 3. Injection of steroid hormones into the local joints fails to give satisfactory results in advanced, chronic rheumatoid arthritis. In such instances the flushing of the joint with physiological saline solution is effective. 4. In the case of chronic rheumatoid arthritis where the inflammation of hand and phalangeal joints is marked, RA-test gives rapid and more intense reaction, and most of such cases are of Follicular-Fibrosis type. 5. When lymph follicles appearing in the synovial membrane are stained when methyl green pyronine, the arrangement of lymphoid cells and plasma cells becomes distinctly clear. By micro-autoradiographic observations it can be seen that ³H-thymindine injected into the joint cavity is mostly ingested by the lymphoid cells in lymph follicles. 6. In the observation by the fluorescent antibody method multinuclear leucocytes found in the joint fluid and in the peripheral blood react with 19S and 7S-gamma-globulins. 7. When the serum and the joint fluid of the patient with rheumatoid arthritis are fractionated, they separate into three peaks at 19S, 7S, and 4S. Both S. S. C. A.-test and L. F. T. tests reveal the peak at 19S. The serum of chronic hepatitis positive to RA-test and the serum of rheumatoid arthritis are found to react immunologically the same to anti-&#946;2 M globulin sheep serum. 8. When the reticulo-endothelial system of rat is blocked by 900,000 molecules of poly-vinyl-pyrroridon, the ability of antibody production is diminished. 9. Chemical synovectomy of injecting osmic acid is effective to FibrinoidCoating type. Its action mechanism lies in the complete cleaning of the surface of synovial membrane. 10. By radiating synovectomy with 193Au a fairly good result can be expected. 198Au is ingested by those cells in the surface layer of the synovial membrane and also by histiocytes in the synovial membrane. When 5 mc of 198Au are injected into the knee joint, a marked necrosis of the synovial membrane occurs. When 198Au is added to the ascites cells of rabbit during the tissue culture, in the concentration of over 14 &#956;C degeneration of these cells can be recognized. 11. From the examination results of prognosis on those 25 cases with 41 rheumatoid knee joints after surgical synovectomy, it is considered that this method is indicated for Follicular-Fibrosis type. Ones with rheumatoid knee joint of Fibrinoid-Coating type gold sol treatment should be resorted to. In the cases of hand joints, surgical synovectemy is to be recommended at a relatively early stage.</p

Hepatocellular Carcinoma with Direct Invasion to the Duodenal Bulb, Presenting with Gastrointestinal Bleeding

Hemorrhage from hepatocellular carcinoma (HCC) directly invading the gastrointestinal tract is very rare. A 71-yearold man, who had been treated with transcatheter arterial embolization and percutaneous ethanol injection for HCC in the right hepatic lobe, presented with melena. Endoscopic examination showed a crater-like ulceration coated with blood clot in the duodenal bulb, and microscopic examination of a biopsy specimen from the duodenal lesion confirmed HCC. Abdominal computed tomography (CT) revealed that the HCC mass containing air-density invaded the duodenum. Recurrent bleeding continued from the lesion and the patient died of liver failure. Postmortem examination revealed massive HCC with hepatoduodenal fistula caused by direct tumor invasion into the duodenum

Visual Properties of Transgenic Rats Harboring the Channelrhodopsin-2 Gene Regulated by the Thy-1.2 Promoter

Channelrhodopsin-2 (ChR2), one of the archea-type rhodopsins from green algae, is a potentially useful optogenetic tool for restoring vision in patients with photoreceptor degeneration, such as retinitis pigmentosa. If the ChR2 gene is transferred to retinal ganglion cells (RGCs), which send visual information to the brain, the RGCs may be repurposed to act as photoreceptors. In this study, by using a transgenic rat expressing ChR2 specifically in the RGCs under the regulation of a Thy-1.2 promoter, we tested the possibility that direct photoactivation of RGCs could restore effective vision. Although the contrast sensitivities of the optomotor responses of transgenic rats were similar to those observed in the wild-type rats, they were enhanced for visual stimuli of low-spatial frequency after the degeneration of native photoreceptors. This result suggests that the visual signals derived from the ChR2-expressing RGCs were reinterpreted by the brain to form behavior-related vision