Structural origins of the unusual thermal stability of amorphous CuxGe50-xTe50(0⩽x⩽33.3)

We have investigated the local atomic structures of several compositions of the amorphous phase of the system Cu_xGe50-xTe₅₀(0⩽x⩽33.3), based on extended x-ray absorption fine-structure as well as anomalous x-ray scattering experiments, and discuss the unusual trend regarding their thermal stability as a function of the Cu content. At low concentrations (x⩽15), Cu atoms tend to agglomerate in flat nanoclusters reminiscent of the crystalline phase of metallic Cu, leading to a more and more Ge-deficient Ge-Te host network structure with growing Cu content and an increasing thermal stability. At higher Cu concentrations (x⩾25), Cu is incorporated into the network, leading to an overall weaker bonding situation which is associated with a decreasing thermal stability.

Collective excitations in a melt of fast phase change material GeCu2Te3

Inelastic x-ray scattering measurements have been carried out to investigate atomic dynamics in a melt of fast phase change material GeCu₂Te₃. The dynamic structure factor was analysed using the model function with three damped harmonic oscillator components. By investigating the correlation between the excitation energy and the linewidth, and that between the excitation energy and the intensity on contour maps of a relative approximate probability distribution function proportional toexp(-χ2/N), we could judge the reliability of each inelastic excitation in the dynamic structure factor. The results indicate that there are two inelastic excitation modes besides the longitudinal acoustic one in the liquid. The lower energy excitation could be assigned to the transverse acoustic one whereas the higher energy one disperses like fast sound. The latter result may imply that the liquid ternary alloy exhibits a microscopic phase separation tendency.

Low energy excitation in liquid Sb and liquid Bi observed in inelastic x-ray scattering spectra

The dynamic structure factorS(Q,E), whereQandEare momentum and energy transfer, respectively, has been measured for liquid Sb, using inelastic x-ray scattering. A modified damped harmonic oscillator model function was applied to analyseS(Q,E) of liquid Sb and also to that of liquid Bi by Inuiet al(2015Phys. Rev.B92, 054206). The obtained excitation energy was in fairly good agreement with that predicted byab initiomolecular dynamics simulations on these liquid semi-metals. The excitation energy of the longitudinal acoustic mode in liquid Sb and liquid Bi exhibits flat-toppedQdependence whereas the lower excitation energy below the longitudinal acoustic excitation showsQ-gap behaviour. From the viscosity estimated from theQ-gap experimentally obtained, it is inferred that the lower energy excitation arises from the transverse acoustic excitation in the liquids.

Experimental observation of density fluctuations in liquid metals associated with liquid-liquid, liquid-gas and metal-nonmetal transitions

We have developed a special technique and succeeded to carry out small-angle x-ray scattering measurements for some liquid metal systems. The purpose is to investigate effects of transitions such as liquid-liquid (LLT), liquid-gas (LGT) and metal-nonmetal (MNMT) transitions on mesoscopic density fluctuations in liquids. In liquid Te systems (Se-Te and Ge-Te mixtures), which show continuous LLT accompanying MNMT, parameters of density fluctuations show maxima almost in the middle of the transition, both in strength and spatial size. This work (and Kajihara et al 2012 Phys. Rev. B86 214202) was the first direct observation that density fluctuations exhibit maximum corresponding to LLT. However in this study, we could not clearly separate the effects of LLT and MNMT on the observed density fluctuations. Thus, we also investigated fluid Hg under high pressure and high temperature conditions, which shows MNMT near a critical point of LGT, to investigate how MNMT affects them. We observed distinct density fluctuations; a strength and a correlation length of them show maxima at around a critical isochore of LGT, and the former is basically consistent with a phase diagram (compressibility) of LGT; they do not show any peaks at MNMT region. Precise analysis revealed that MNMT only affects a shift of another parameter, a short-range correlation length. These results in fluid Hg indicate that the density fluctuations are mainly derived from a critical phenomena of LGT and MNMT does not play any critical role on them. We believe that the latter conclusion also holds true for liquid Te systems; MNMT plays no important role on the density fluctuations in liquid Te systems and LLT is the main origin of them.

Peculiar temperature dependence of dynamical sound speed in liquid Se50Te50 by inelastic x-ray scattering

Inelastic x-ray scattering (IXS) measurements were carried out on liquid Se₅₀Te₅₀ at temperatures up to 1323 K to investigate how the atomic dynamics changes with temperature through the semiconductor-metal transition. The acoustic mode was clearly observed in the dynamic structure factor and its energy was determined using a damped harmonic oscillator model. The dynamical sound speed obtained by IXS for [Formula: see text] nm^-1 was found to behave similarly to the temperature dependence of ultrasonic sound velocity with a minimum near the semiconductor metal transition. The results can be explained by taking liquid Se₅₀Te₅₀ to be an inhomogeneous liquid consisting of metallic and semiconducting domains whose size is approximately 3 nm. The relaxation time obtained from frequency dependence of the dynamical sound speed was on a picosecond time scale.

Static and dynamic structures of liquid Ba8Ga16Sn30: a melt of the thermoelectric clathrate compounds

X-ray diffraction and inelastic x-ray scattering measurements of liquid Ba₈Ga₁₆Sn₃₀ have been carried out to investigate local structure and atomic dynamics in the liquid. The pair distribution function shows shorter and longer interatomic distances in the first coordination shell. The dynamic structure factor exhibits the inelastic excitations on both sides of the quasielastic central peak. The inelastic excitations disperse with increasing the momentum transfer, suggesting the longitudinal acoustic mode. We found a low energy excitation in addition to the longitudinal acoustic excitation in the dynamic structure factor and it reminds us a strong relationship with a rattling motion of a guest (Ba) atom in the solid state. The temperature dependence of the pair distribution function and the longitudinal acoustic excitation energy is very weak in a range from 600 to 900 °C. The result suggests that Ba and other atoms in the melt are located around minimum positions of the effective pair potential approximated as a harmonic one.

Viscoelastic anomaly accompanying anti-crossing behaviour in liquid As2Se3

We investigate the dynamic structure factor of the melt of the well known glass former, As₂Se₃, using inelastic x-ray scattering for temperatures, T, [Formula: see text] K and momentum transfers Q from [Formula: see text] nm^-1. An anomaly was observed at Q  =  2.7 nm^-1 ([Formula: see text] K) with, in the context of a simple model, both an abrupt change in frequency and an increased linewidth reminiscent of an anti-crossing in a solid. Comparison with structural information from reverse Monte Carlo modeling of x-ray diffraction data allows us to associate the disappearance of the anomaly at higher temperatures with a drop in the number of mechanical constraints per atom, n _mc, to [Formula: see text] reminiscent of the threshold applicable for glass formation in rigidity theory. It is inferred that the surprising jump in the dispersion in the liquid may be correlated with a stiffness transition in a network glass.

Living Related Renal Transplantation Using a Saphenous Vein Graft: A Case Report

We report a case of living related renal transplantation that used the recipient's saphenous vein as a graft to extend the length of the right donor renal vein. A 41-year-old woman underwent ABO-incompatible living related renal transplantation from her 74-year-old mother in November 2014. A retroperitoneal laparoscopic right donor nephrectomy was performed, because the right kidney showed a cyst on preoperative computed tomography. As the right kidney after donor nephrectomy had a short renal vein and the kidney was large at 280 g, anastomosis with the external iliac vein was difficult. Therefore, we obtained the recipient's 15-cm-long right saphenous vein and created a 1 cm saphenous vein graft. We anastomosed 1 side of the saphenous vein graft to the allograft renal vein in bench surgery and performed end-to-side anastomosis of the other end to the recipient's external iliac vein. The allograft renal artery was used to perform end-to-end anastomosis to the recipient's internal iliac artery. Allograft kidney function was good after transplantation. When the longer axis of the renal graft vein is short, as in the right kidney, a saphenous vein graft may be useful.

ABO-Incompatible Living Kidney Transplants: Evolution of Outcomes and Immunosuppressive Management

ABO-incompatible living kidney transplantation (ABO-ILKT) has steadily become more widespread. However, the optimal immunosuppressive regimen for ABO-ILKT remains uncertain. We aimed to determine the longitudinal changes in the outcomes from ABO-ILKT compared with those from ABO-compatible living kidney transplantation (ABO-CLKT) over the last 25 years. Of 1195 patients who underwent living kidney transplantations (LKT) at our institute between 1989 and 2013, 1032-including 247 ABO-ILKT and 785 ABO-CLKT cases-were evaluated for graft survival, patient survival, infectious adverse events, and renal function. The patients were divided into four groups according to the transplantation era and ABO-compatibility. In the past decade, ABO-ILKT and ABO-CLKT recipients yielded almost equivalent outcomes with respect to the 9-year graft survival rates, which were 86.9% and 92.0%, respectively (hazard ratio [HR] 1.38, 95% confidence interval [CI] 0.59-3.22, p = 0.455). The graft survival rate for ABO-ILKT conducted between 2005 and 2013 was better than that for ABO-ILKT conducted between 1998 and 2004 (HR 0.30, 95% CI 0.13-0.72, p = 0.007). ABO-ILKT recipients showed substantial improvements in the graft survival rate over time. Graft survival was almost identical over the past decade, regardless of ABO-incompatibility. Currently, ABO-ILKT is an acceptable treatment for patients with end-stage renal disease.

Transverse excitations in liquid Fe, Cu and Zn

Transverse acoustic (TA) excitation modes were observed in inelastic x-ray scattering spectra of liquid Fe, Cu and Zn. From the analysis of current correlation functions, we concluded that TA excitation modes can experimentally be detected through the quasi-TA branches in the longitudinal current correlation spectra in these liquid metals. The microscopic elastic constants are estimated and a characteristic difference from macroscopic polycrystalline value was found in Poisson's ratio of liquid Fe, which shows an extremely softer value of ∼0.38 compared with the macroscopic value of ∼0.275. The lifetime of the TA modes were determined to be ∼0.45 ps for liquid Fe and Cu and ∼0.55 ps for liquid Zn, reflecting different interatomic correlations between liquid transition metals and non-transition metals. The propagation length of the TA modes are ∼0.85 nm in all of liquid metals, corresponding to the size of icosahedral or similar size of cages formed instantaneously in these liquid metals.

Expression of B7-H3, a potential factor of tumor immune evasion in combination with the number of regulatory T cells, affects against recurrence-free survival in breast cancer patients

Background

In the tumor microenvironment, factors inhibiting the targeting of cancer cells by activated T cells have recently been noted. B7-H3 belongs to the B7 superfamily of immune regulatory ligands and plays an important role in the adaptive immune response of co-inhibitory/stimulatory factors in regulating T cells. However, the degree to which B7-H3 directly affects tumor immune evasion mechanisms remains unclear, particularly in patients with breast cancer. Regulatory T cells (Tregs) are known as a key player in the inhibition of immune mechanisms. The present study demonstrated that expression of B7-H3 on tumor cells and the number of Tregs in the tumor microenvironment independently affected prognosis in breast cancer patients.

Methods

We immunohistochemically investigated the presence of B7-H3 and forkhead box P3 (Foxp3)-positive Tregs in pathological specimens from 90 patients with breast cancer.

Results

Positive B7-H3 expression was associated with shorter recurrence-free survival (RFS) (p = 0.014). A higher percentage of Foxp3-positive cells also correlated with shorter RFS (p = 0.039). Multivariate analysis showed B7-H3 as an independent factor on RFS. Foxp3 expression in tumor-infiltrating lymphocytes (TILs) correlated significantly with larger tumor size (>2 cm), expression of human epidermal growth factor receptor 2 (HER2), and higher nuclear grade (p = 0.003, p < 0.001, p = 0.001, respectively). No correlation was identified between expression of B7-H3 and the percentage of Foxp3-positive TILs.

Conclusions

B7-H3 and Foxp3 can be regarded as markers of poor prognosis in breast cancer. These expressions were not correlated, suggesting that B7-H3 expression plays an independent role in tumor immune evasion, regardless of Tregs.

Transverse excitations in liquid Sn

Transverse acoustic (TA) excitation modes were observed in inelastic x-ray scattering (IXS) spectra of liquid Sn. The excitation energies and widths of the TA modes are in good agreement with results of an ab initio molecular dynamics simulation. By comparing current correlation spectra between the experimental and theoretical results quantitatively, we have concluded that the TA modes can be detected experimentally through the quasi-TA branches in the longitudinal current correlation spectra. The lifetime and propagation length of the TA modes were determined to be ~0.7 ps and 0.8-1.0 nm, respectively, corresponding to the size of cages formed instantaneously in liquid Sn.

Signaling crosstalk between TGFβ and Dishevelled/Par1b

Crosstalk of signaling pathways is critical during metazoan development and adult tissue homeostasis. Even though the transforming growth factor-beta (TGFβ) transduction cascade is rather simple, in vivo responsiveness to TGFβ ligands is tightly regulated at several steps. As such, TGFβ represents a paradigm for how the activity of one signaling system is modulated by others. Here, we report an unsuspected regulatory step involving Dishevelled (Dvl) and Par1b (also known as MARK2). Dvl and Par1b cooperate to enable TGFβ/bone morphogenetic protein (BMP) signaling in Xenopus mesoderm development and TGFβ responsiveness in mammalian cells. Mechanistically, the assembly of the Par1b/Dvl3/Smad4 complex is fostered by Wnt5a. The association of Smad4 to Dvl/Par1 prevents its inhibitory ubiquitination by ectodermin (also known as transcriptional intermediary factor 1 gamma or tripartite motif protein 33). We propose that this crosstalk is relevant to coordinate TGFβ responses with Wnt-noncanonical and polarity pathways.

First example of multi-scale reverse Monte Carlo modeling for small-angle scattering experimental data using reverse mapping from coarse-grained particles to atoms

We propose a new method for multi-scale reverse Monte Carlo (RMC) modeling of small-angle scattering data using reverse mapping from coarse-grained particles to atoms in cases where scale separation cannot be assumed. For efficient RMC analysis for small-angle scattering data, it is important to determine a large scale structure with the lowest possible computing cost. In order to find this large scale structure, a method using coarse-grained particles instead of atoms is suitable. As our first example, we examine the structure of expanded fluid Hg near the critical point. For this system, small-angle x-ray scattering (SAXS) data and wide-angle x-ray diffraction data (XRD) are observed in the same thermodynamic state. First, RMC analysis using coarse-grained particles for SAXS data is performed. Second, RMC analysis for SAXS and XRD data is performed with the replacement of a coarse-grained particle by an ad hoc cluster of several Hg atoms. In the present study, we have determined that the size of one coarse-grained particle corresponds to ten Hg atoms. The number density for the coarse-grained particles is set to one-tenth the actual number density of atoms and the cutoff length is three times (6.9 Å) that of Hg atoms (2.3 Å). As a result, this approach is found to be successful and the computing cost of RMC analysis can be reduced.