On the Nature and Elimination of Stimulus Artifact in Nerve Signals Evoked and Recorded Using Surface Electrodes

The electrical stimulus pulse and the surface electrodes commonly used to study compound action potentials of peripheral nerves give rise to an artifact consisting of an initial spike and a longer lasting tail which often interferes with the recorded signal. The artifact has four sources: 1) the voltage gradient between the recording electordes caused by stimulus current flowing through the limb, 2) the common-mode voltage of the limb caused by current escaping through the ground electrode, 3) the capacitive coupling between the stimulating and recording leads, and 4) the high-pass filtering characteristics of the recording amplifier. This paper models these sources and presents several methodological rules for minimizing their effects. Also presented are three computer-based methods for subtracting the residual artifact from contaminated records using estimates of the artifact obtained from: 1) subthreshold stimulation, 2) a second recording site remote from the nerve, or 3) stimulation during the refractory period of the nerve.     

Evaluation of the Lifetime and Thermal Conductivity of Dysprosia-Stabilized Thermal Barrier Coating Systems

The aim of this study was the further development of dysprosia-stabilized zirconia coatings for gas turbine applications. The target for these coatings was a longer lifetime and higher insulating performance compared to today’s industrial standard thermal barrier coating. Two morphologies of ceramic top coat were studied: one using a dual-layer system and the second using a polymer to generate porosity. Evaluations were carried out using a laser flash technique to measure thermal properties. Lifetime testing was conducted using thermo-cyclic fatigue testing. Microstructure was assessed with SEM and Image analysis was used to characterize porosity content. The results show that coatings with an engineered microstructure give performance twice that of the present reference coating.     

The 2016 Thermal Spray Roadmap

Considerable progress has been made over the last decades in thermal spray technologies, practices and applications. However, like other technologies, they have to continuously evolve to meet new problems and market requirements. This article aims to identify the current challenges limiting the evolution of these technologies and to propose research directions and priorities to meet these challenges. It was prepared on the basis of a collection of short articles written by experts in thermal spray who were asked to present a snapshot of the current state of their specific field, give their views on current challenges faced by the field and provide some guidance as to the R&D required to meet these challenges. The article is divided in three sections that deal with the emerging thermal spray processes, coating properties and function, and biomedical, electronic, aerospace and energy generation applications.     

Immunohistochemical staining for bcl-2 and mcl-1 in intrathyroidal epithelial thymoma (ITET)/carcinoma showing thymus-like differentiation (CASTLE) and cervical thymic carcinoma

Intrathyroidal epithelial thymoma (ITET)/carcinoma showing thymus-like differentiation (CASTLE), a rare thyroid neoplasm, was recently shown to be immunoreactive for CD5, providing immunophenotypic evidence of previously postulated thymic differentiation. To assess whether ectopic malignant neoplasms with thymic differentiation display other markers associated with thymic carcinoma, we studied five cases of ITET/CASTLE, two cases of cervical thymic carcinoma, and one case of cervical thymoma for bcl-2 and mcl-1 immunoreactivity. Both of these antiapoptosis proto-oncogenes have been reported to be expressed by the majority of true thymic carcinomas but only a minority of thymomas. All of the five cases of ITET/CASTLE, both CD5-positive cervical thymic carcinomas, and one CD5-negative cervical thymoma were immunoreactive for bcl-2, as were 10 (91%) of 11 thymic carcinomas arising in the thymus, in contrast to 6 (25%) of 24 benign and invasive thymomas arising in the thymus. Similarly, all of the five cases of ITET/CASTLE, both cervical thymic carcinomas, but not the cervical thymoma, were immunoreactive for mcl-1, as were 9 (90%) of 10 thymic carcinomas, in contrast to 6 (33%) of 18 benign and invasive thymomas. We conclude that dual immunoreactivity for bcl-2 and mcl-1 is a feature of malignant neoplasms with thymic differentiation in general, both within the thymus and at ectopic sites.     

Flow and heat transfer in a film of viscous liquid on a rotating disk

A numerical method employing a computer is used to investigate the hydrodynamics and heat transfer of a thin film of incompressible viscous liquid on a rotating disk for the case of laminar flow when it is possible to neglect surface tension, body forces, and friction between liquid film and gas medium.     

The basis for self-tolerance of natural killer cells in beta2-microglobulin- and TAP-1- mice

Cells from mice with mutations in the genes for beta2-microglobulin (beta2m) or for TAP-1 express only low levels of MHC class I proteins on their surfaces, and are thus sensitive to attack by normal NK cells. Although NK cells are present in beta2m- mice and TAP-1(-) mice, they are completely self-tolerant. The underlying mechanism for this tolerance is unknown. It has been proposed that education processes render NK cells from these mice hypersensitive to class I-mediated inhibition, so that they can be inhibited even by the low levels of class I expressed on autologous cells. In this study, we present evidence against this hypothesis, by demonstrating that NK cells from beta2m- mice and TAP-1(-) mice fail to attack beta2m(-)TAP-1(-) double-mutant cells in both in vitro and in vivo assays. The latter cells express substantially lower levels of class I than single-mutant cells, based on serologic tests, as well as a significantly diminished sensitivity to attack by class I-specific CTL. Furthermore, the Ly-49 repertoire on NK cells derived from beta2m(-)TAP-1(-) mice is highly similar to that of either single mutant, indicating that the developmental processes that shape the Ly-49 repertoire cannot respond to the differences in class I levels among these mice. We propose that self-tolerance of NK cells in beta2m- mice and TAP-1(-) mice is likely to result from hyporesponsiveness of the cells to activating signals, or alternatively, to induction of inhibitory signaling through receptors specific for non-class I MHC ligands.     

Raising powder steel wear resistance by electrocontact coating with white cast iron

A process has been developed for hardening powder steel by surface coating with white cast iron. The electrical and chemicothermal parameters have been determined theoretically. Formulas are derived that define the heating conditions and cooling rate. Structural features of the hardened layers have been examined. Electrocontact melting raises the resistance to wear in SP60 powder steel under conditions of dry friction and lubricated friction by a factor six by comparison with hardened high-speed steel.     

Substitutes for leadership: test of a construct.

The study reported here examined the impact of leadership substitutes on subordinate job satisfaction and organizational commitment. Leadership substitutes, as suggested by Kerr (1977), replace or "act in the place of" a specific leader behavior. Multiple regression was used to test the validity and strength of potential substitutes. Results indicated mixed support for the substitutes construct.     

Novel telomeric repeat elongation assay performed on zinc oxide nanorod array supports

We developed a highly sensitive and effective telomeric repeat elongation (TRE) assay by exploiting the fluorescence signal enhancing ability of ZnO nanorod (NR) platforms. We report that this novel ZnO NR-based TRE assay can be successfully used for detecting active telomerase. Our TRE assays enable complex biological reactions between many different biological components to take place effectively on various ZnO NR platforms. Therefore, ZnO NRs can effectively determine telomerase activity even at ultratrace concentration level, by functioning as excellent fluorescence enhancing biosupports. We also show the potential of ZnO NR-based TRE assays in a high-throughput and multiplexed screening of active telomerase in a large number of samples. As telomerase is a useful biomarker in cancer diagnosis and screening, our ZnO NR-based TRE assays may prove to be not only useful in basic biological research but also in clinical testing.