Nanoscale Oxide Formation at α-Al2O3–Nb Interfaces

Parts for metallurgical applications made from refractory metal–ceramic composites offer improved thermal shock resistance due to their capability for resistive heating compared to ones made solely from ceramics such as Al₂O₃. The combination of Al₂O₃ and Nb is intriguing as both show similar thermal expansion behavior over a wide temperature range. The high affinity of Nb for O to form nonprotective oxides, however, hampers its use in oxidative environments. Formation of such phases at the ceramic–metal interface can have detrimental effects on the cohesion of the composites. For this work, nanocrystalline Nb films are deposited on sapphire substrates by magnetron sputtering to study diffusion of O and high-temperature phase formation at a refractory metal–ceramic interface during heat treatment under Ar at 1600 °C. A combined approach of atom probe tomography and transmission electron microscopy for compositional and crystallographic analyses reveals that at triple junctions of the sapphire–Nb interface with Nb grain boundaries, heterogeneous nucleation of nanoscale NbO₂ occurs, which further reacts with Al₂O₃ to form AlNbO₄, while the Nb film itself remains metallic. Fast O transport through grain boundaries leads to internal oxidation at the interface, whereas regions further away from Nb grain boundaries remain unchanged.     

Synthesis of Novel Nitroxoline Analogs with Potent Cathepsin B Exopeptidase Inhibitory Activity

Nitroxoline, a well-known antimicrobial agent, has been identified in several independent studies, and on different molecular targets, as a promising candidate to be repurposed for cancer treatment. One specific target of interest concerns cathepsin B, a lysosomal peptidase involved in the degradation of the extracellular matrix (ECM), leading to tumor invasion, metastasis and angiogenesis. However, dedicated optimization of the nitroxoline core is needed to actually deliver a nitroxoline-based antitumor drug candidate. Within that context, 34 novel nitroxoline analogs were synthesized and evaluated for their relative cathepsin B inhibitory activity, their antiproliferative properties and their antimicrobial activity. More than twenty analogs were shown to exert a similar or even slightly higher cathepsin B inhibitory activity compared to nitroxoline. The implemented modifications of the nitroxoline scaffold and the resulting SAR information can form an eligible basis for further optimization toward more potent cathepsin B inhibitors in the quest for a clinical nitroxoline-based antitumor agent.     

Binomial CUSUM chart with curtailment

The binomial cumulative sum (CUSUM) chart has been widely used to monitor the fraction nonconforming (p) of a process. It is a powerful procedure for detecting small and moderate p shifts. This article proposes a binomial CUSUM control chart using curtailment technique (Curt_CUSUM chart in short). The new chart is able to improve the overall detection effectiveness while holding the false alarm rate at a specified level. The results of the comparative studies show that, on average, the Curt_CUSUM chart is more effective than the CUSUM chart without curtailment by 30%, in terms of Average Number of Defectives, under different circumstances. The Curt_CUSUM chart can be applied to a 100% inspection as well as a general random sampling inspection.     

In vitro Synthesis of New Cyclodepsipeptides of the PF1022‐Type: Probing the α‐D‐Hydroxy Acid Tolerance of PF1022 Synthetase

The nonribosomal peptide synthetase PF1022‐synthetase (PFSYN) synthesises the cyclooctadepsipeptide PF1022 from the building blocks D ‐lactate, D ‐phenyllactate and N‐methylleucine. The substrate tolerance of PFSYN for hydroxy acids was probed by in vitro screening of a set of aliphatic and aromatic α‐D ‐hydroxy acids with various structural modifications in the side chain. Thus, new PF1022 derivatives for example, propargyl‐D ‐lactyl‐PF1022 and β‐thienyl‐D ‐lactyl‐PF1022 were generated. The promiscuous behaviour of PFSYN towards aliphatic and aromatic α‐D ‐hydroxy acids is considerably larger than that of related enniatin synthetase (ESYN) and thus gives rise to the enzymatic generation of various new PF1022 derivatives.     

Application of PSRK for Process Design

A survey about the current status and potential of the predictive Soave-Redlich-Kwong (PSRK) group contribution equation of state (EoS) is given. The PSRK method combines the SRK EoS with the UNIFAC group contribution model by the PSRK mixing rule. The availability of a large number of interaction parameters between UNIFAC and new PSRK main groups allows calculating the phase equilibrium behavior and other thermodynamic quantities for various kinds of systems even with strong electrolytes. Different fields of application are discussed: the prediction of gas solubilities in asymmetric systems, the air solubility calculated for mixed solvents, the removal of H₂S from natural gas by predicting the physical absorption, and the calculation of the enthalpy effects of absorption processes with pressure and temperature.     

Importance of characterizing a reference filter test system

Standards governing the performance of air filters are there to enable comparisons to be made between different filter tests. However, measurement data from different filter test systems can vary widely, making comparisons difficult. Palas GmbH, Germany, has developed a modifed test system that it says meets the minimum requirements of a reference filter test system.     

UV polarizers based on oriented poly(vinyl alcohol)–Chrysophenine–Congo red blend films

The availability of efficient low‐cost ultraviolet (UV) film polarizers is of vital importance to a number of applications, which rely on the use of polarized light in the near‐UV regime. We describe here the preparation of such elements based on stretch‐oriented films comprising poly(vinyl alcohol) and a combination of two commercially available azo dyes, Congo Red and Chrysophenine. Films of various dye contents were prepared and oriented by uniaxial tensile deformation. Moderately stretched films (draw ratio l/l₀ = 4–8) exhibit a pronounced optical dichroism, characterized by a polarizing efficiency up to 0.98 at a wavelength of 365 nm. Initial experiments suggest that, even under rather harsh irradiation conditions and without any packaging, these azo‐dye‐based polarizers are surprisingly inert under simulated operating conditions. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1235–1239, 2002     

The steady-state behavior of multivariate exponentially weighted moving average control charts

Abstract

Multivariate exponentially weighted moving average (MEWMA) charts are popular, handy, and effective procedures to detect distributional changes in a stream of multivariate data. For doing appropriate performance analysis, dealing with the steady-state behavior of the MEWMA statistic is essential. Going beyond early papers, we derive quite accurate approximations of the respective steady-state densities of the MEWMA statistic. It turns out that these densities could be rewritten as the product of two functions depending on one argument only that allows feasible calculation. For proving the related statements, the presentation of the noncentral chi-square density deploying the confluent hypergeometric limit function is applied. Using the new methods it was found that for large dimensions, the steady-state behavior becomes different from what one might expect from the univariate monitoring field. Based on the integral equation driven methods, steady-state and worst-case average run lengths are calculated with higher accuracy than before. Eventually, optimal MEWMA smoothing constants are derived for all considered measures.     

Unit root testing with slowly varying trends

A unit root test is proposed for time series with a general nonlinear deterministic trend component. It is shown that asymptotically the pooled OLS estimator of overlapping blocks filters out any trend component that satisfies some Lipschitz condition. Under both fixed‐b and small‐b block asymptotics, the limiting distribution of the t‐statistic for the unit root hypothesis is derived. Nuisance parameter corrections provide heteroskedasticity‐robust tests, and serial correlation is accounted for by pre‐whitening. A Monte Carlo study that considers slowly varying trends yields both good size and improved power results for the proposed tests when compared to conventional unit root tests.     

Biosynthesis and localization of phosphatidyl-scyllo-inositol in barley aleurone cells

A novel isomer of phosphatidylinositol (PI), phosphatidyl-scyllo-inositol, was characterized in the aleurone cells of barley seeds. In this investigation, the subcellular localization of scyllo-PI and the relative rates of biosynthesis and accumulation of [³²P]phosphoric acid ([³²Pi])-labeled scyllo- and myo-phosphoinositides in the plasma membrane and intracellular membrane pools were investigated. About 25% of the [³²Pi]-labeled phospholipids were present in plasma membrane and 75% in intracellular membranes. Incorporation of [³²Pi] into scyllo-PI was greater than into myo-PI in both the plasma membranes and intracellular membranes at all time points investigated, thus suggesting a higher rate of biosynthesis; however, the data do not preclude reduced breakdown of labeled scyllo-PI as a contributing factor. In vitro studies were conducted to investigate the presence of cytidinediphosphate diacylglycerol (CDP-DG):scyllo-inositol 3-phosphatidyltransferase (scyllo-PI synthase) and to optimize enzymatic activity. The inclusion of nonionic detergents (Brij 58 and Triton X-100) effected significant enhancement in the biosynthesis of scyllo-PI, whereas anionic, cationic, and zwitterionic detergents had little or no effect. This is the first evidence for CDP-DG:scyllo-inositol 3-phosphatidyltransferase activity.