Novel deformation-induced polymorphic crystallization and softening of Al-based amorphous alloys

© 2018 Acta Materialia Inc. Melt-spun amorphous ribbons of Al 90 Y 10 (at.%) (90Al) and Al 84 Y 8.5 Ni 4 Co 2 Pd 1 Fe 0.5 (84Al) are cold-rolled at near to liquid-nitrogen temperature or at room temperature, inducing partial crystallization to nanoscale fcc-Al (α-Al). The crystallization is characterized and contrasted with the distinct sequences of reactions on annealing 90Al and 84Al amorphous alloys. Rolling-induced crystallization leads to softening, opposite to the effect of nanocrystallization induced by annealing. The origins of the hardness changes are analyzed. The rolling induces novel polymorphic crystallization to α-Al with extended solid solubility. This transformation, which occurs equally in 84Al and 90Al, despite the much greater thermal stability of the former, allows the ribbons to retain good bending ductility, and delays the onset of embrittlement on subsequent annealing. Partial crystallization induced by cold-rolling is useful in avoiding the formation of compound phases associated with brittleness, and is a promising process for high-solute Al-based amorphous alloys to be further developed as structural materials

Anomalous structure in the single particle spectrum of the fractional quantum Hall effect

The two-dimensional electron system (2DES) is a unique laboratory for the physics of interacting particles. Application of a large magnetic field produces massively degenerate quantum levels known as Landau levels. Within a Landau level the kinetic energy of the electrons is suppressed, and electron-electron interactions set the only energy scale. Coulomb interactions break the degeneracy of the Landau levels and can cause the electrons to order into complex ground states. In the high energy single particle spectrum of this system, we observe salient and unexpected structure that extends across a wide range of Landau level filling fractions. The structure appears only when the 2DES is cooled to very low temperature, indicating that it arises from delicate ground state correlations. We characterize this structure by its evolution with changing electron density and applied magnetic field. We present two possible models for understanding these observations. Some of the energies of the features agree qualitatively with what might be expected for composite Fermions, which have proven effective for interpreting other experiments in this regime. At the same time, a simple model with electrons localized on ordered lattice sites also generates structure similar to those observed in the experiment. Neither of these models alone is sufficient to explain the observations across the entire range of densities measured. The discovery of this unexpected prominent structure in the single particle spectrum of an otherwise thoroughly studied system suggests that there exist core features of the 2DES that have yet to be understood.Comment: 15 pages, 10 figure

Delayed blood transfusion is associated with mortality following radical cystectomy

Objectives: To examine the temporal association between blood transfusion and 90-day mortality in patients with bladder cancer treated with radical cystectomy. / Methods: This represents a retrospective cohort study of patients treated with radical cystectomy within the Premier Hospital network between 2003 and 2015. Patients outcomes were stratified those who received early blood transfusion (day of surgery) vs delayed blood transfusion (postoperative day ≥1) during the index admission. Primary end point was 90-day mortality following surgery. / Results: The median age of 12,056 patients identified was 70 years. A total of 7,201 (59.7%) patients received blood transfusion. Within 90 days following surgery, 57 (2.2%), 162 (5.9%) and 123 (6.7%) patients in the early, delayed and both early and delayed transfused patients died respectively. Following multivariate logistic regression to account for patient (age and Charlson Comorbidity Index [CCI]) and hospital (surgeon volume, surgical approach and academic status) factors, delayed blood transfusion was independently associated with 90-day mortality (Odds ratio [OR], 2.64; 95% Confidence Interval [CI], 1.98–3.53; p < 0.001). A sensitivity analysis defining early blood transfusion as <2 days postoperatively, increased 90-day mortality persisted in patients receiving delayed transfusion (OR, 2.20; 95% CI, 1.63-3.00; p < 0.001). Older patients (≥77 years) with the highest CCI (≥2) had a 7% absolute increase in the predicted probability of 90-day mortality if they were transfused late compared to patients transfused early. / Conclusion: Patient undergoing cystectomy may benefit from expedited transfusion to prevent subsequent clinical deterioration which may lead to patient mortality. Future work is needed to elucidate the optimal timing of blood transfusion

Non-universal minimal Z' models: present bounds and early LHC reach

We consider non-universal 'minimal' Z' models, whose additional U(1) charge is a non-anomalous linear combination of the weak hypercharge Y, the baryon number B and the partial lepton numbers (L_e, L_mu, L_tau), with no exotic fermions beyond three standard families with right-handed neutrinos. We show that the observed pattern of neutrino masses and mixing can be fully reproduced by a gauge-invariant renormalizable Lagrangian, and flavor-changing neutral currents in the charged lepton sector are suppressed by a GIM mechanism. We then discuss the phenomenology of some benchmark models. The electrophilic B-3L_e model is significantly constrained by electroweak precision tests, but still allows to fit the hint of an excess observed by CDF in dielectrons but not in dimuons. The muonphilic B-3L_mu model is very mildly constrained by electroweak precision tests, so that even the very early phase of the LHC can explore significant areas of parameter space. We also discuss the hadrophobic L_mu-L_tau model, which has recently attracted interest in connection with some puzzling features of cosmic ray spectra.Comment: 29 pages, 13 figure

Holographic Anomalous Conductivities and the Chiral Magnetic Effect

We calculate anomaly induced conductivities from a holographic gauge theory model using Kubo formulas, making a clear conceptual distinction between thermodynamic state variables such as chemical potentials and external background fields. This allows us to pinpoint ambiguities in previous holographic calculations of the chiral magnetic conductivity. We also calculate the corresponding anomalous current three-point functions in special kinematic regimes. We compare the holographic results to weak coupling calculations using both dimensional regularization and cutoff regularization. In order to reproduce the weak coupling results it is necessary to allow for singular holographic gauge field configurations when a chiral chemical potential is introduced for a chiral charge defined through a gauge invariant but non-conserved chiral density. We argue that this is appropriate for actually addressing charge separation due to the chiral magnetic effect.Comment: 17 pages, 1 figure. v2: 18 pages, 1 figure, discussion clarified throughout the text, references added, version accepted for publication in JHE

Efficacy of three BCG strains (Connaught, TICE and RIVM) with or without secondary resection (re-TUR) for intermediate/high-risk non-muscle-invasive bladder cancers: results from a retrospective single-institution cohort analysis

Purpose: (I) To evaluate the clinical efficacy of three different BCG strains in patients with intermediate-/high-risk non-muscle-invasive bladder cancer (NMIBC). (II) To determine the importance of performing routine secondary resection (re-TUR) in the setting of BCG maintenance protocol for the three strains. Methods: NMIBCs who received an adjuvant induction followed by a maintenance schedule of intravesical immunotherapy with BCG Connaught, TICE and RIVM. Only BCG-naïve and those treated with the same strain over the course of follow-up were included. Cox proportional hazards model was developed according to prognostic factors by the Spanish Urological Oncology Group (CUETO) as well as by adjusting for the implementation of re-TUR. Results: n = 422 Ta-T1 patients (Connaught, n = 146; TICE, n = 112 and RIVM, n = 164) with a median (IQR) follow-up of 72 (60-85) were reviewed. Re-TUR was associated with improved recurrence and progression outcomes (HRRFS: 0.63; 95% CI 0.46-0.86; HRPFS: 0.55; 95% CI 0.31-0.86). Adjusting for CUETO risk factors and re-TUR, BGC TICE and RIVM provided longer RFS compared to Connaught (HRTICE: 0.58, 95% CI 0.39-0.86; HRRIVM: 0.61, 95% CI 0.42-0.87) while no differences were identified between strains for PFS and CSS. Sub-analysis of only re-TUR cases (n = 190, 45%) showed TICE the sole to achieve longer RFS compared to both Connaught and RIVM. Conclusion: Re-TUR was confirmed to ensure longer RFS and PFS in intermediate-/high-risk NMIBCs but did not influence the relative single BCG strain efficacy. When routinely performing re-TUR followed by a maintenance BCG schedule, TICE was superior to the other strains for RFS outcomes

Radial Corrugations of Multi-Walled Carbon Nanotubes Driven by Inter-Wall Nonbonding Interactions

We perform large-scale quasi-continuum simulations to determine the stable cross-sectional configurations of free-standing multi-walled carbon nanotubes (MWCNTs). We show that at an inter-wall spacing larger than the equilibrium distance set by the inter-wall van der Waals (vdW) interactions, the initial circular cross-sections of the MWCNTs are transformed into symmetric polygonal shapes or asymmetric water-drop-like shapes. Our simulations also show that removing several innermost walls causes even more drastic cross-sectional polygonization of the MWCNTs. The predicted cross-sectional configurations agree with prior experimental observations. We attribute the radial corrugations to the compressive stresses induced by the excessive inter-wall vdW energy release of the MWCNTs. The stable cross-sectional configurations provide fundamental guidance to the design of single MWCNT-based devices and shed lights on the mechanical control of electrical properties

Mechanical Stress Inference for Two Dimensional Cell Arrays

Many morphogenetic processes involve mechanical rearrangement of epithelial tissues that is driven by precisely regulated cytoskeletal forces and cell adhesion. The mechanical state of the cell and intercellular adhesion are not only the targets of regulation, but are themselves likely signals that coordinate developmental process. Yet, because it is difficult to directly measure mechanical stress {\it in vivo} on sub-cellular scale, little is understood about the role of mechanics of development. Here we present an alternative approach which takes advantage of the recent progress in live imaging of morphogenetic processes and uses computational analysis of high resolution images of epithelial tissues to infer relative magnitude of forces acting within and between cells. We model intracellular stress in terms of bulk pressure and interfacial tension, allowing these parameters to vary from cell to cell and from interface to interface. Assuming that epithelial cell layers are close to mechanical equilibrium, we use the observed geometry of the two dimensional cell array to infer interfacial tensions and intracellular pressures. Here we present the mathematical formulation of the proposed Mechanical Inverse method and apply it to the analysis of epithelial cell layers observed at the onset of ventral furrow formation in the {\it Drosophila} embryo and in the process of hair-cell determination in the avian cochlea. The analysis reveals mechanical anisotropy in the former process and mechanical heterogeneity, correlated with cell differentiation, in the latter process. The method opens a way for quantitative and detailed experimental tests of models of cell and tissue mechanics

Simvastatin inhibits TLR8 signaling in primary human monocytes and spontaneous TNF production from rheumatoid synovial membrane cultures

Simvastatin has been shown to have anti-inflammatory effects that are independent of its serum cholesterol lowering action, but the mechanisms by which these anti-inflammatory effects are mediated have not been elucidated. To explore the mechanism involved, the effect of simvastatin on Toll-like receptor (TLR) signalling in primary human monocytes was investigated. A short pre-treatment with simvastatin dose-dependently inhibited the production of tumor necrosis factor-α (TNF) in response to TLR8 (but not TLRs 2, 4, or 5) activation. Statins are known inhibitors of the cholesterol biosynthetic pathway, but intriguingly TLR8 inhibition could not be reversed by addition of mevalonate or geranylgeranyl pyrophosphate; downstream products of cholesterol biosynthesis. TLR8 signalling was examined in HEK 293 cells stably expressing TLR8, where simvastatin inhibited IKKα/β phosphorylation and subsequent NF-κB activation without affecting the pathway to AP-1. Since simvastatin has been reported to have anti-inflammatory effects in RA patients and TLR8 signalling contributes to TNF production in human RA synovial tissue in culture, simvastatin was tested in these cultures. Simvastatin significantly inhibited the spontaneous release of TNF in this model which was not reversed by mevalonate. Together, these results demonstrate a hitherto unrecognized mechanism of simvastatin inhibition of TLR8 signalling that may in part explain its beneficial anti-inflammatory effects

The Sphaleron Rate in SU(N) Gauge Theory

The sphaleron rate is defined as the diffusion constant for topological number NCS = int g^2 F Fdual/32 pi^2. It establishes the rate of equilibration of axial light quark number in QCD and is of interest both in electroweak baryogenesis and possibly in heavy ion collisions. We calculate the weak-coupling behavior of the SU(3) sphaleron rate, as well as making the most sensible extrapolation towards intermediate coupling which we can. We also study the behavior of the sphaleron rate at weak coupling at large Nc.Comment: 18 pages with 3 figure