Microstructure and elastic modulus evolution of TiTaNb alloys.

In order to develop Ti based alloys with promising biocompatibility and matching mechanical response with human bone, TiTaNb alloys with 15, 23 and 30 mass% Ta are designed and systematically examined in terms of microstructural evolution and mechanical response. The Ti-30mass%Ta-10mass%Nb is demonstrated to be satisfactory with an elastic modulus ~60 GPa, hardness ~3.1 GPa, and strength ~1250 MPa. The evolution trend of the resulting microstructure and phases as a function of Ta content and annealing temperature are established. The relationship between the various phase amounts and alloy moduli is explored.

Unexpected observation of splitting of skyrmion phase in Zn doped Cu2OSeO3.

Polycrystalline (Cu1-xZnx)2OSeO3 (0≤x≤0.2) samples were synthesized using solid-state reaction and characterized by X-ray diffraction (XRD). The effect of Zn doping upon saturation magnetization (MS) indicates that the Zn favors to occupying Cu(II) square pyramidal crystallographic site. The AC susceptibility (χ'ac) was measured at various temperatures (χ'ac-T) and magnetic field strengths (χ'ac-H). The Zn doping concentration is found to affect greatly the M-T and χ'ac-T. The skyrmion phase has been inferred from the χ'ac-H data, and then indicated within the H-T phase diagrams for various Zn doping concentrations. The striking and unexpected observation is that the skyrmion phase region becomes split upon Zn doping concentration. Interestingly, second conical boundary accompanied by second skyrmion phase was also observed from dχ'ac/dH vs. H curves. Atomic site disorder created by the chemical doping modulates the delicate magnetic interactions via change in the Dzyaloshinskii-Moriya (DM) vector of distorted Cu(II) square pyramidal, thereby splitting of skyrmion phase might occur. These findings illustrate the potential of using chemical and atomic modification for tuning the temperature and field dependence of skyrmion phase of Cu2OSeO3.

Improvement of bio-corrosion resistance for Ti42Zr40Si15Ta3 metallic glasses in simulated body fluid by annealing within supercooled liquid region.

The effects of the nanocrystalline phases on the bio-corrosion behavior of highly bio-friendly Ti42Zr40Si15Ta3 metallic glasses in simulated body fluid were investigated, and the findings are compared with our previous observations from the Zr53Cu30Ni9Al8 metallic glasses. The Ti42Zr40Si15Ta3 metallic glasses were annealed at temperatures above the glass transition temperature, Tg, with different time periods to result in different degrees of α-Ti nano-phases in the amorphous matrix. The nanocrystallized Ti42Zr40Si15Ta3 metallic glasses containing corrosion resistant α-Ti phases exhibited more promising bio-corrosion resistance, due to the superior pitting resistance. This is distinctly different from the previous case of the Zr53Cu30Ni9Al8 metallic glasses with the reactive Zr2Cu phases inducing serious galvanic corrosion and lower bio-corrosion resistance. Thus, whether the fully amorphous or partially crystallized metallic glass would exhibit better bio-corrosion resistance, the answer would depend on the crystallized phase nature.

Association between use of FK506 and prevalence of post-transplantation diabetes mellitus in kidney transplant patients.

BACKGROUND: Tacrolimus (FK506) use has been suggested as a risk factor for post-transplantation diabetes mellitus (PTDM) because it can impair insulin secretion. This association warrants further investigation. This study aimed to examine the prevalence of PTDM and its association with FK506 use in kidney transplant recipients. The study also aimed to examine the relationship of FK506 use and diabetes-related biologic markers. METHODS: A retrospective chart review was used to collect data at a medical center in northern Taiwan from September 2003 to February 2012. PTDM was defined with the use of the criteria of the American Diabetes Association. RESULTS: Among 166 patients included in the analysis, PTDM was reported in 49 patients (29.5%). A total of 93 patients used the FK506 regimen, of whom 34 (36.6%) were PTDM cases. Logistic regression showed that FK506 use (odds ratio [OR], 2.71; 95% confidence interval [CI], 1.20-6.11; P = .016) and older age (OR,1.08; 95% CI, 1.03-1.13; P = .001) were significant risk factors for PTDM. In addition, FK506 use in PTDM cases was associated with a significantly higher hemoglobin A1c level (7.55 vs 5.81; P = .01) and a borderline significantly higher insulin resistance index (3.24 vs 1.92; P = .053) than was FK506 use without the presence of PTDM. CONCLUSIONS: Older age and an FK506 regimen were important predictors of the prevalence of PTDM. Greater early detection and prevention efforts for PTDM are needed for older transplant recipients. PTDM patients with an FK506 regimen had higher hemoglobin A1c levels and insulin resistance index than did patients who did not use FK506. The association of serum indicators with FK506 use in the prevalence of PTDM warrants further investigation.

Does mycophenolate mofetil increase the incidence of infections in stable renal transplant recipients initially treated with a two-drug regimen?

BACKGROUND: A drug regimen including a calcineurin inhibitor (cyclosporine or tacrolimus) and prednisone has been the mainstay of maintenance immunosuppression in our renal transplant recipients for more than 10 years. After the introduction of mycophenolate mofetil (MMF), a new, potent immunosuppressant that may reduce the incidence of late rejection in renal transplant recipients, the immunosuppressive protocol in some recipients was changed to an MMF-based regimen. We sought to ascertain whether the addition of MMF lead to greater susceptibility to infectious complications. PATIENTS AND METHODS: Between May 1991 and November 2002, all renal transplant recipients who received a two-drug regimen initially for more than 6 months were changed to an MMF-based regimen. The study includes patients with functional grafts for more than 6 months thereafter. Differences in the incidence, etiology, and outcome of infections were compared during the non-MMF versus the MMF periods. RESULTS: Eighty patients of mean age of 38.6 years (range 13 to 69) included 43 men and 37 women. The mean daily MMF dose was 663 mg/patient (range 250 to 1500 mg). The mean follow-up time of non-MMF period and MMF periods were 3.4 and 2.1 years, respectively. The overall incidence of infections in the two periods was similar (0.2 infections/patient in the non-MMF period and 0.25 infections/patient in the MMF period, P = .57). No mortality was associated with these infectious complications. In conclusion, addition of MMF, a more potent immunosuppressive protocol, did not increase the incidence of infections in stable renal transplant recipients initially treated with a two-drug regimen.

An intelligent emissions controller for fuel lean gas reburn in coal-fired power plants.

The application of artificial intelligence techniques for performance optimization of the fuel lean gas reburn (FLGR) system is investigated. A multilayer, feedforward artificial neural network is applied to model static nonlinear relationships between the distribution of injected natural gas into the upper region of the furnace of a coal-fired boiler and the corresponding oxides of nitrogen (NOx) emissions exiting the furnace. Based on this model, optimal distributions of injected gas are determined such that the largest NOx reduction is achieved for each value of total injected gas. This optimization is accomplished through the development of a new optimization method based on neural networks. This new optimal control algorithm, which can be used as an alternative generic tool for solving multidimensional nonlinear constrained optimization problems, is described and its results are successfully validated against an off-the-shelf tool for solving mathematical programming problems. Encouraging results obtained using plant data from one of Commonwealth Edison's coal-fired electric power plants demonstrate the feasibility of the overall approach. Preliminary results show that the use of this intelligent controller will also enable the determination of the most cost-effective operating conditions of the FLGR system by considering, along with the optimal distribution of the injected gas, the cost differential between natural gas and coal and the open-market price of NOx emission credits. Further study, however, is necessary, including the construction of a more comprehensive database, needed to develop high-fidelity process models and to add carbon monoxide (CO) emissions to the model of the gas reburn system.

Acute disseminated encephalomyelitis after Rocky Mountain spotted fever.

Although acute disseminated encephalomyelitis has been observed after a variety of viral infections and an occasional bacterial infection, it has not been reported in association with rickettsial infections. Reported is a 7-year-old male with magnetic resonance images and clinical manifestations suggestive of acute disseminated encephalomyelitis after a tick bite and serologically proven Rocky Mountain spotted fever.

A facile synthesis and carbon-13 nuclear magnetic resonance spectral properties of 7-ketocholesteryl benzoate.

This paper presents a modified method of the selective allylic oxidation of cholesteryl benzoate. Pyridinium chlorochromate, in refluxing benzene, has been found to be an effective and convenient reagent for the efficient oxidation of cholesteryl benzoate to 7-ketocholesteryl benzoate in high yield. Also included herein are the carbon-13 nuclear magnetic resonance spectral properties of 7-ketocholesteryl benzoate and cholesteryl benzoate.

Diffusion rates of cell surface antigens of mouse-human heterokaryons. I. Analysis of the population.

The rate of appearance, in a newly formed heterokaryon population, of cells bearing completely intermixed mouse and human surface antigens may be used to estimate diffusion constants for antigens on individual cells. From this estimate, it appears that the surface antigens in most cells do not diffuse at the rate expected, but rather move more slowly, by a factor of ten or more, than expected from either measured or calculated diffusion constants for proteins freely mobile in the plane of a lipid membrane. Differences in diffusion rates between cells are not due to effects of Sendai virus, or of trypsin. Restrictions on diffusion are apparently not due to cytochalasin B- or Colcemid-sensitive elements.

Diffusion rates of cell surface antigens of mouse-human heterokaryons. II. Effect of membrane potential on lateral diffusion.

The rate of appearance, in a population of mouse-human heterokaryons, of cells with intermixed mouse and human surface antigens may be used to estimate the rate of lateral diffusion of the antigens in a single cell. Most heterokaryons appear to restrict diffusion of their surface antigens. These restrictions are altered by exposing either heterokaryons or their parent cells to conditions that change cell surface membrane potential. Media containing unphysiological concentrations of potassium ion, drugs, affecting the Na+,K+ ATPase, or a channel-forming antibiotic, gramicidin, all affect lateral mobility of cell surface antigens in a manner consistent with a common effect on membrane potential.