Reactions of TiNi with Oxygen

X-ray diffraction and metallography have been applied to study the formation conditions for the phase in Ti₄Ni₂O in the reaction of TiNi with oxygen. The phase diagram for the Ti Ni O system indicates that the phase (Fe₃W₃C structure type) is a solid solution of oxygen in Ti₂Ni. For TiNi made in an oxygen-bearing medium or from initial materials contaminated with oxygen, one gets the phase and Ni₃Ti. Those phases are formed also in surface oxidation as products from the initial interaction of the alloy with oxygen. They occur when there is a low oxygen partial pressure, as on annealing TiNi powder in a vacuum given by a rotary pump or in a layer under scale formed on a cast TiNi specimen on oxidation in air. The layer under the scale is formed because of the preferential loss of titanium from the TiNi and consists of Ti₄Ni₂O, Ni₃Ti, and an Ni(Ti) solid solution, which in turn occurs because of preferential loss of titanium from Ni₃Ti. In the subsequent oxidation stages, there is selective oxidation of Ti₄Ni₂O to lower titanium oxides. The decomposition of TiNi alloy containing oxygen when the composition is varied near the equiatomic one can be used for practical purposes. For example, the segregation of the hydride-forming phase may improve the hydrogen uptake by the alloy, while the dispersed segregation of Ni₃Ti and the lower oxides may favor hardening.     

Coating of intravascular balloon with paclitaxel prevents constrictive remodeling of the dilated porcine femoral artery due to inhibition of intimal and media fibrosis

Here we investigated how a coating of intravascular balloon with paclitaxel (drug-coated balloon; DCB, Freeway?) impacted porcine peripheral artery vascular function and remodeling. Domestic swine (n = 54) underwent percutaneous overstretch balloon dilation of femoral and iliac arteries, controlled by angiography and optical coherence tomography (OCT). Paclitaxel tissue uptake was measured at 1 h and 1, 3, and 9 days post-dilation. At these time-points and at 32 ± 2 days, vascular function of the dilated arteries was assessed using the organ chamber model. Neointimal growth and remodeling indices were determined using OCT and histology at 32 ± 2 days. Intima and media fibrosis were quantified by picrosirius red staining. Post-inflation femoral artery tissue drug levels were 460 ± 214, 136 ± 123, 14 ± 6, and 0.1 ± 0.1 ng/mg at 1 h and 1, 3, and 9 days, respectively. Compared to plain balloon, Freeway? resulted in a significantly smaller neointimal area (P < 0.05), less tunica intima (8.0 ± 5.4 vs 14.2 ± 4.7 %) and media fibrosis (15.6 ± 7.7 vs 24.5 ± 5.4 %), and less femoral artery constrictive remodeling (remodeling index: 1.08 ± 0.08 vs 0.94 ± 0.08). The DCB was associated with significantly increased vasoconstrictor tone and endothelium-dependent vasodilation impairment shortly after post-overstretch injury. Overall, DCB dilation of peripheral arteries resulted in high drug uptake into arterial tissue. Compared with the plain balloon, the DCB was associated with decreased vessel wall fibrosis after balloon overstretch injury, and reduced degrees of constrictive remodeling and neointimal hyperplasia.     

N‐acetylcysteine may improve residual renal function in hemodialysis patients: A pilot study

Clinical outcomes in chronic dialysis patients are highly dependent on preservation of residual renal function (RRF). N‐acetylcysteine (NAC) may have a positive effect on renal function in the setting of nephrotoxic contrast media administration. In our recent study, we showed that NAC may improve RRF in peritoneal dialysis patients. The aim of the present study was to investigate the effect of NAC on RRF in patients treated with chronic hemodialysis. Prevalent chronic hemodialysis patients with a residual urine output of at least 100 mL/24 hours were included. The patients were administered oral NAC 1200 mg twice daily for 2 weeks. Residual renal function was assessed at baseline and at the end of treatment using a midweek interdialytic urine collection for measurement of urine output and calculation of residual renal Kt/V and glomerular filtration rate (GFR). Residual GFR was measured as the mean of urea and creatinine residual renal clearance. Each patient served as his own control. Twenty patients were prospectively enrolled in the study. Administration of NAC 1200 mg twice daily for 2 weeks resulted in significant improvement in RRF: urine volume increased from 320 ± 199 to 430 ± 232 mL/24 hours (P < 0.01), residual renal Kt/V increased from 0.19 ± 0.12 to 0.29 ± 0.14 (P < 0.01), and residual GFR increased from 1.6 ± 1.6 to 2.4 ± 2.3 mL/minute/1.73 m² (P < 0.01). N‐acetylcysteine may improve RRF in patients treated with chronic hemodialysis.     

Refractory Diborides of Zirconium and Hafnium

This paper reviews the crystal chemistry, synthesis, densification, microstructure, mechanical properties, and oxidation behavior of zirconium diboride (ZrB₂) and hafnium diboride (HfB₂) ceramics. The refractory diborides exhibit partial or complete solid solution with other transition metal diborides, which allows compositional tailoring of properties such as thermal expansion coefficient and hardness. Carbothermal reduction is the typical synthesis route, but reactive processes, solution methods, and pre-ceramic polymers can also be used. Typically, diborides are densified by hot pressing, but recently solid state and liquid phase sintering routes have been developed. Fine-grained ZrB₂ and HfB₂ have strengths of a few hundred MPa, which can increase to over 1 GPa with the addition of SiC. Pure diborides exhibit parabolic oxidation kinetics at temperatures below 1100°C, but B₂O₃ volatility leads to rapid, linear oxidation kinetics above that temperature. The addition of silica scale formers such as SiC or MoSi₂ improves the oxidation behavior above 1100°C. Based on their unique combination of properties, ZrB₂ and HfB₂ ceramics are candidates for use in the extreme environments associated with hypersonic flight, atmospheric re-entry, and rocket propulsion.     

Spatially resolved recording of transient fluorescence‐lifetime effects by line‐scanning TCSPC

We present a technique that records transient changes in the fluorescence lifetime of a sample with spatial resolution along a one‐dimensional scan. The technique is based on scanning the sample with a high‐frequency pulsed laser beam, detecting single photons of the fluorescence light, and building up a photon distribution over the distance along the scan, the arrival times of the photons after the excitation pulses and the time after a stimulation of the sample. The maximum resolution at which lifetime changes can be recorded is given by the line scan period. Transient lifetime effects can thus be resolved at a resolution of about one millisecond. We demonstrate the technique for recording photochemical and nonphotochemical chlorophyll transients in plants and transient changes in free Ca²⁺ in cultured neurons. Microsc. Res. Tech. 77:216–224, 2014. © 2014 Wiley Periodicals, Inc.     

Development of Sandwich Double-Competitive ELISA for Sulfonamides. Comparative Analytical Characteristics and Matrix Effect Resistance

Sandwich enzyme-linked immunosorbent assay (ELISA) of sulfonamides based on double-competitive interaction between haptenized protein as a captured antigen and analyte for binding to immobilized and enzyme-labeled antibodies was developed. This experimental assay format was examined in analytical properties and matrix effect resistance in comparison with usual ones: indirect, direct antigen-coated and antibody-coated ELISAs. All four assay formats were designed on the basis of interactions between the previously prepared monoclonal antibody and immunizing hapten, 4-(4-(4-aminophenylsulfonamido) phenyl)butanoic acid, providing the uniform output optical signal for correct comparison of each assay characteristic. The sensitivity (IC₅₀) of the developed competitive sandwich assay was rather below 100 ng/ml for 11 sulfonamides which was suitable for their determination in milk, muscles and animal sera at established maximum residue limit concentration. Comparative examination did not reveal changes in assay specificity, and advantages in sensitivity, matrix effect resistance, and procedure duration before commonly used assay formats. Moreover, new design of assay was shown to be three-fold more consumable in antibody reagents in comparison with direct assay formats.     

Type XX Collagen Is Elevated in Circulation of Patients with Solid Tumors

In the tumor microenvironment, the extracellular matrix (ECM) has been recognized as an important part of cancer development. The dominant ECM proteins are the 28 types of collagens, each with a unique function in tissue architecture. Type XX collagen, however, is poorly characterized, and little is known about its involvement in cancer. We developed an ELISA quantifying type XX collagen, named PRO-C20, using a monoclonal antibody raised against the C-terminus. PRO-C20 and PRO-C1, an ELISA targeting the N-terminal pro-peptide of type I collagen, was measured in sera of 219 patients with various solid cancer types and compared to sera levels of 33 healthy controls. PRO-C20 was subsequently measured in a separate cohort comprising 36 patients with pancreatic ductal adenocarcinoma (PDAC) and compared to 20 healthy controls and 11 patients with chronic pancreatitis. PRO-C20 was significantly elevated in all cancers tested: bladder, breast, colorectal, head and neck, kidney, lung, melanoma, ovarian, pancreatic, prostate, and stomach cancer (p < 0.01–p < 0.0001). PRO-C1 was only elevated in patients with ovarian cancer. PRO-C20 could discriminate between patients and healthy controls with AUROC values ranging from 0.76 to 0.92. Elevated levels were confirmed in a separate cohort of patients with PDAC (p < 0.0001). High PRO-C20 levels (above 2.57 nM) were predictive of poor survival after adjusting for the presence of metastasis, age, and sex (HR: 4.25, 95% CI: 1.52–11.9, p-value: 0.006). Circulating type XX collagen is elevated in sera of patients with various types of cancer and has prognostic value in PDAC. If validated, PRO-C20 may be a novel biomarker for patients with solid tumors and can help understand the ECM biology of cancer.     

Correctors Rescue CFTR Mutations in Nucleotide‐Binding Domain 1 (NBD1) by Modulating Proteostasis

We evaluated whether small molecule correctors could rescue four nucleotide‐binding domain 1 (NBD1) mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene (A455E, S492F, ΔI507, and R560T). We first transfected Cos‐7 cells (green monkey kidney cells) with A455E, S492F, ΔI507, or R560T and created HEK‐293 (human embryonic kidney cells) cell lines stably expressing these CFTR mutations. The mutants showed lowered protein expression, instability at physiological temperature, and rapid degradation. After treatment with correctors CFFT‐002, CFFT‐003, C3, C4, and/or C18, the combination of C18+C4 showed the most correction and resulted in increased CFTR residing in the plasma membrane. We found a profound decrease in binding of CFTR to histone deacetylases (HDAC) 6 and 7 and heat shock proteins (Hsps) 27 and 40. Silencing Hsp27 or 40 rescued the mutants, but no additional amount of CFTR was rescued when both proteins were knocked down simultaneously. Thus, CFTR mutations in NBD1 can be rescued by a combination of correctors, and the treatment alters the interaction between mutated CFTR and the endoplasmic reticulum machinery.     

Empirical assessment of the impact of highway design exceptions on the frequency and severity of vehicle accidents

Compliance to standardized highway design criteria is considered essential to ensure roadway safety. However, for a variety of reasons, situations arise where exceptions to standard-design criteria are requested and accepted after review. This research explores the impact that such design exceptions have on the frequency and severity of highway accidents in Indiana. Data on accidents at carefully selected roadway sites with and without design exceptions are used to estimate appropriate statistical models of the frequency and severity of accidents at these sites using recent statistical advances with mixing distributions. The results of the modeling process show that presence of approved design exceptions has not had a statistically significant effect on the average frequency or severity of accidents - suggesting that current procedures for granting design exceptions have been sufficiently rigorous to avoid adverse safety impacts. However, the findings do suggest that the process that determines the frequency of accidents does vary between roadway sites with design exceptions and those without.     

Experimental Analysis of Hydraulic Solver Convergence with Genetic Algorithms

A procedure for the experimental convergence evaluation of a hydraulic-network solver is proposed, based on using genetic algorithms to search for network parameter values that maximize the number of iterations of the hydraulic-network solver under test. The efficiency of the method is demonstrated by the example of convergence evaluation for the EPANET hydraulic simulator. Examples of a pipe network and of combinations of parameter values for which the static solver of the simulator fails to converge in a reasonable number of iterations are given. The features of the EPANET 2.00.12 solver responsible for loss of convergence are discussed. New criteria for the automatic start of solution damping aimed at improving the convergence of the solver are proposed. The better convergence of the EPANET solver modified in accordance with these criteria is confirmed by the random and the proposed search-based testing method.