Valley-dependent spin polarization in bulk MoS2 with broken inversion symmetry

The valley degree of freedom of electrons is attracting growing interest as a carrier of information in various materials, including graphene, diamond and monolayer transition-metal dichalcogenides. The monolayer transition-metal dichalcogenides are semiconducting and are unique due to the coupling between the spin and valley degrees of freedom originating from the relativistic spin-orbit interaction. Here, we report the direct observation of valley-dependent out-of-plane spin polarization in an archetypal transition-metal dichalcogenide--MoS2--using spin- and angle-resolved photoemission spectroscopy. The result is in fair agreement with a first-principles theoretical prediction. This was made possible by choosing a 3R polytype crystal, which has a non-centrosymmetric structure, rather than the conventional centrosymmetric 2H form. We also confirm robust valley polarization in the 3R form by means of circularly polarized photoluminescence spectroscopy. Non-centrosymmetric transition-metal dichalcogenide crystals may provide a firm basis for the development of magnetic and electric manipulation of spin/valley degrees of freedom.

The use of the transverse acetabular ligament in total hip replacement

It has recently been reported that the transverse acetabular ligament (TAL) is helpful in determining the position of the acetabular component in total hip replacement (THR). In this study we used a computer-assisted navigation system to determine whether the TAL is useful as a landmark in THR. The study was carried out in 121 consecutive patients undergoing primary THR (134 hips), including 67 dysplastic hips (50%). There were 26 men (29 hips) and 95 women (105 hips) with a mean age of 60.2 years (17 to 82) at the time of operation. After identification of the TAL, its anteversion was measured intra-operatively by aligning the inferomedial rim of the trial acetabular component with the TAL using computer-assisted navigation. The TAL was identified in 112 hips (83.6%). Intra-observer reproducibility in the measurement of anteversion of the TAL was high, but inter-observer reproducibility was moderate.

Each surgeon was able to align the trial component according to the target value of the angle of anteversion of the TAL, but it was clear that methods may differ among surgeons. Of the measurements of the angle of anteversion of the TAL, 5.4% (6 of 112 hips) were outliers from the safe zone.

In summary, we found that the TAL is useful as a landmark when implanting the acetabular component within the safe zone in almost all hips, and to prevent it being implanted in retroversion in all hips, including dysplastic hips. However, as anteversion of the TAL may be excessive in a few hips, it is advisable to pay attention to individual variations, particularly in those with severe posterior pelvic tilt.

Cite this article: Bone Joint J 2014;96-B:306–11.

The use of the transverse acetabular ligament in total hip replacement: An analysis of the orientation of the trial acetabular component using a navigation system

It has recently been reported that the transverse acetabular ligament (TAL) is helpful in determining the position of the acetabular component in total hip replacement (THR). In this study we used a computer-assisted navigation system to determine whether the TAL is useful as a landmark in THR. The study was carried out in 121 consecutive patients undergoing primary THR (134 hips), including 67 dysplastic hips (50%). There were 26 men (29 hips) and 95 women (105 hips) with a mean age of 60.2 years (17 to 82) at the time of operation. After identification of the TAL, its anteversion was measured intra-operatively by aligning the inferomedial rim of the trial acetabular component with the TAL using computer-assisted navigation. The TAL was identified in 112 hips (83.6%). Intra-observer reproducibility in the measurement of anteversion of the TAL was high, but inter-observer reproducibility was moderate. Each surgeon was able to align the trial component according to the target value of the angle of anteversion of the TAL, but it was clear that methods may differ among surgeons. Of the measurements of the angle of anteversion of the TAL, 5.4% (6 of 112 hips) were outliers from the safe zone. In summary, we found that the TAL is useful as a landmark when implanting the acetabular component within the safe zone in almost all hips, and to prevent it being implanted in retroversion in all hips, including dysplastic hips. However, as anteversion of the TAL may be excessive in a few hips, it is advisable to pay attention to individual variations, particularly in those with severe posterior pelvic tilt.

Effect of ghrelin and anamorelin (ONO-7643), a selective ghrelin receptor agonist, on tumor growth in a lung cancer mouse xenograft model

Purpose

Anamorelin (ONO-7643) is an orally active ghrelin receptor agonist in development for non-small cell lung cancer (NSCLC)-related anorexia/cachexia. It displays both orexigenic and anabolic properties via ghrelin mimetic activity and transient increases in growth hormone (GH). However, increasing GH and insulin-like growth factor-1 in cancer patients raises concerns of potentially stimulating tumor growth. Therefore, we investigated the effect of ghrelin and anamorelin on tumor growth in a murine NSCLC xenograft model.

Methods

Female nude mice (15–21/group) with established A549 tumors were administered ghrelin (2 mg/kg i.p.), anamorelin (3, 10, or 30 mg/kg p.o.), or vehicle controls daily for 28 days. Tumor growth, food consumption, and body weight were monitored. Murine growth hormone (mGH) and murine insulin-like growth factor-1 (mIGF-1) were measured in plasma.

Results

Tumor growth progressed throughout the study, with no significant differences between treatment groups. Daily food consumption was also relatively unchanged, while the percentage of mean body weight gain at the end of treatment was significantly increased in animals administered 10 and 30 mg/kg compared with controls (p < 0.01). Peak mGH levels were significantly higher in ghrelin- and anamorelin-treated animals than in controls, while peak mIGF-1 levels were slightly elevated but not statistically significant. All regimens were well tolerated.

Conclusions

These findings demonstrate that neither anamorelin nor ghrelin promoted tumor growth in this model, despite increased levels of mGH and a trend of increased mIGF-1. Together with anamorelin’s ability to increase body weight, these results support the clinical development of ghrelin receptor agonist treatments for managing NSCLC-related anorexia/cachexia.

The effects of long-term exposure to ozokerite mainly consisting of an aliphatic series of hydrocarbons using F344 rats

Combined chronic toxicity and carcinogenicity studies of ozokerite (OZK), a natural wax substance used as a food additive for a gum base, were performed in male and female F344 rats. Dietary concentrations of 0%, 0.05%, 0.1% and 0.2% OZK were applied in a 52-week chronic toxicity study and 0%, 0.1% and 0.2% in a 104-week carcinogenicity study. In the chronic toxicity study, treatment with OZK caused a xenobiotic reaction against absorbed OZK, including formation of histiocytosis and granulomas with crystalline material in many organs in all of the treated males and females. Particularly in the liver, granulomatous inflammation was accompanied by hepatocellular vacuolation and changes in the serum biochemical parameters indicative of hepatic disorder. The number and area of glutathione S-transferase placental form (GST-P) positive foci were increased in all of the treated groups of both sexes, suggesting the proliferative effect of OZK. In the carcinogenicity study, the incidence of hepatocellular adenoma and the total tumor incidence in the liver of all of the treated males were significantly increased compared with the controls. In conclusion, long-term exposure to OZK caused systemic chronic inflammation due to a foreign body response. OZK was weakly carcinogenic in the liver of male F344 rats.

Topological surface states with persistent high spin polarization across the Dirac point in Bi2Te2Se and Bi2Se2Te

Helical spin textures with marked spin polarizations of topological surface states have been unveiled for the first time by state-of-the-art spin- and angle-resolved photoemission spectroscopy for two promising topological insulators, Bi(2)Te(2)Se and Bi(2)Se(2)Te. Their highly spin-polarized natures are found to be persistent across the Dirac point in both compounds. This novel finding paves a pathway to extending the utilization of topological surface states of these compounds for future spintronic applications.

The interaction between Lyn and FcεRIβ is indispensable for FcεRI-mediated human mast cell activation

BACKGROUND

FcεRIβ reportedly functions as an amplifier of the FcεRIγ-mediated activation signal using a reconstitution system. However, the amplification mechanisms in human mast cells (MCs) are poorly understood. We previously reported the hyperexpression of FcεRIβ of MCs in giant papillae from vernal keratoconjunctivitis patients, compared with that in conjunctivae from nonallergic conjunctivitis patients. Elucidation of the molecular mechanisms of the amplification induced by FcεRIβ should provide new targets for novel therapeutic interventions. The aim is to understand in greater details the function of FcεRIβ in human MC FcεRI expression and signaling.

METHODS

FcεRIβ and Lyn expression was reduced using a lentiviral shRNA silencing technique. Localization of Lyn and FcεRIβ in cultured MCs was examined by confocal microscopic analysis. Mediators were measured by ELISAs.

RESULTS

The diminution of FcεRIβ significantly downregulated cell surface FcεRI expression and FcεRI-mediated mediator release/production. The downregulation of FcεRI-mediated degranulation was not only due to the decrease in FcεRI expression. The diminution of FcεRIβ inhibited the redistribution of Lyn within the cell membrane following IgE sensitization. The diminution of Lyn in MCs significantly downregulated FcεRI-mediated degranulation. The recombinant cell-penetrating forms of phosphorylated FcεRIβ immunoreceptor tyrosine-based activation motif (ITAM) for intracellular delivery disturbed the interaction between Lyn and phosphorylated endogenous FcεRIβ ITAM, resulted in inhibiting IgE-dependent histamine release from MCs in vitro and from giant papillae specimens ex vivo.

CONCLUSION

The interaction between Lyn and FcεRIβ is indispensable for FcεRI-mediated human MC activation, and specific inhibition of the interaction may represent a new therapeutic strategy for the treatment of human allergic diseases.

Experimental verification of PbBi2Te4 as a 3D topological insulator

The experimental evidence is presented of the topological insulator state in PbBi2Te4. A single surface Dirac cone is observed by angle-resolved photoemission spectroscopy with synchrotron radiation. Topological invariants Z2 are calculated from the ab initio band structure to be 1;(111). The observed two-dimensional isoenergy contours in the bulk energy gap are found to be the largest among the known three-dimensional topological insulators. This opens a pathway to achieving a sufficiently large spin current density in future spintronic devices.

Spin-polarized Dirac-cone-like surface state with d character at W(110)

The surface of W(110) exhibits a Dirac-cone-like state with d character within a spin-orbit-induced symmetry gap. As a function of the wave vector parallel to the surface, it shows a nearly massless energy dispersion and a pronounced spin polarization, which is antisymmetric with respect to the Brillouin zone center. In addition, the observed constant energy contours are strongly anisotropic for all energies. This discovery opens new pathways to the study of surface spin-density waves arising from a strong Fermi surface nesting as well as d-electron-based topological properties.

Surface scattering via bulk continuum states in the 3D topological insulator Bi2Se3

We have performed scanning tunneling microscopy and differential tunneling conductance (dI/dV) mapping for the surface of the three-dimensional topological insulator Bi(2)Se(3). The fast Fourier transformation applied to the dI/dV image shows an electron interference pattern near Dirac node despite the general belief that the backscattering is well suppressed in the bulk energy gap region. The comparison of the present experimental result with theoretical surface and bulk band structures shows that the electron interference occurs through the scattering between the surface states near the Dirac node and the bulk continuum states.

Hydroxyapatite Coating on Thermal Titanium Substrate in Aqueous Solution

A hydroxyapatite, HAP, film was deposited on a titanium substrate in an aqueous solution, at an ambient temperature and ambient pressure. The solution included 3 mmoldm-3 Ca(H2PO4)2 and 7 mmol dm-3 CaCl2 at pH 5.5. The temperature of the substrate surface was controlled in both methods of applying alternative current through the Ti foil and high frequency induction heating using Ti ingot. In these methods, the substrate was heated up and the temperature gradient was formed between the substrate and the solution. The effects of surface temperature, fluoride ions, additive inhibitor and heating time on the morphology of HAP crystals formed on Ti substrate were investigated in various conditions. The morphology changed from compact layer to dendrite layer with the HAP growing time in AC current method and the HAP film with the thickness of 200 μm can be obtained on Ti foil with cross section of 30 μm × 2mm by heating for 20 min at 20 A-AC. On the other hand, the deposits consisted of algae-like whisker in the induction heating method. The HAP formation is found to take place only on the substrate surface by these substrate heating methods without HAP precipitation in aqueous solution

In-Situ Tem Characterization of Whiskers on Al Electrodes for Thin-Film Transistors

The recent attention paid to stress migration of aluminum (Al) electrodes in thin-film transistor liquid crystal display (TFT-LCD) applications indicates that wiring materials with low electrical resistivities are of considerable interest for their potential use in higher-resolution displays. In this paper, we firstly describe how as-grown Al whiskers on Al electrodes fabricated on a LCD-grade glass substrate can be characterized by means of a high-voltage transmission electron microscope (HV-TEM) operated at 1 MV. The whiskers ranging from 300 to 400 nm in diameter are sufficient to be transparent to high-voltage electrons. This allows detailed observation of whisker characteristics such as its morphology and crystallography. In most cases, the as-grown Al whiskers in our study had straight rod shapes, and could be regarded as single crystals. Secondly, we report on the in-situ fabrication and observation of Al whiskers at elevated temperature with the HV-TEM. Since relatively thick TEM samples (up to about 1 mm) can be set on a sample holder in the HV-TEM, various growth stages of Al whiskers can be investigated under various heating conditions. Finally, we demonstrate a TEM sample preparation method for the cross-section of an individual Al whisker, using focused ion beam (FIB) etching. This technique makes it possible to reduce the thickness of an Al whisker close to the root. Both bright- and dark-field TEM images provide nanostructural information on the whisker/Al thin-film interface.

Experimental realization of a three-dimensional topological insulator phase in ternary chalcogenide TlBiSe₂

We report the first observation of a topological surface state on the (111) surface of the ternary chalcogenide TlBiSe₂ by angle-resolved photoemission spectroscopy. By tuning the synchrotron radiation energy we reveal that it features an almost ideal Dirac cone with the Dirac point well isolated from bulk continuum states. This suggests that TlBiSe₂ is a promising material for realizing quantum topological transport.