A Simple Method for a Protective Coating on Stainless Steel against Molten Aluminum Alloy Comprising Polymer-Derived Ceramics,Oxides and Refractory Ceramics

A new coating based on polymer-derived ceramics (PDC), oxides and refractory ceramic with a thickness of around 50 µm has been developed to improve the resistance corrosion of stainless steel substrate against molten aluminum alloy in a thermal energy storage (TES) system designed to run at high temperature (up to 600 °C). These coatings implemented by straightforward methods, like tape casting or paintbrush, were coated on planar and cylindrical stainless-steel substrates, pyrolyzed at 700 °C before being plunged for 600 and 1200 h in molten AlSi₁₂ at 700 °C. The stainless-steel substrate appears healthy without intermetallic compounds, characteristic of molten aluminum alloy corrosion. The protective coating against AlSi₁₂ corrosion shows excellent performance and appears interesting for TES applications.     

Testing of Materials and Elements in Civil Engineering

This issue is proposed and organized as a means to present recent developments in the field of testing of materials in civil engineering. For this reason, the articles highlighted in this issue should relate to different aspects of testing of different materials in civil engineering, from building materials and elements to building structures. The current trend in the development of materials testing in civil engineering is mainly concerned with the detection of flaws and defects in elements and structures using destructive, semi-destructive, and nondestructive testing. The trend, as in medicine, is toward designing test equipment that allows one to obtain a picture of the inside of the tested element and materials. Very interesting results with significance for building practices of testing of materials and elements in civil engineering were obtained.     

Conformally Gated Surface Conducting Behaviors of Single-Walled Carbon Nanotube Thin-Film-Transistors

Semiconducting single-walled carbon nanotubes (s-SWCNTs) have gathered significant interest in various emerging electronics due to their outstanding electrical and mechanical properties. Although large-area and low-cost fabrication of s-SWCNT field effect transistors (FETs) can be easily achieved via solution processing, the electrical performance of the solution-based s-SWCNT FETs is often limited by the charge transport in the s-SWCNT networks and interface between the s-SWCNT and the dielectrics depending on both s-SWCNT solution synthesis and device architecture. Here, we investigate the surface and interfacial electro-chemical behaviors of s-SWCNTs. In addition, we propose a cost-effective and straightforward process capable of minimizing polymers bound to s-SWCNT surfaces acting as an interfering element for the charge carrier transport via a heat-assisted purification (HAP). With the HAP treated s-SWCNTs, we introduced conformal dielectric configuration for s-SWCNT FETs, which are explored by a carefully designed wide array of electrical and chemical characterizations with finite-element analysis (FEA) computer simulation. For more favorable gate-field-induced surface and interfacial behaviors of s-SWCNT, we implemented conformally gated highly capacitive s-SWCNT FETs with ion-gel dielectrics, demonstrating field-effect mobility of ~8.19 cm²/V⋅s and on/off current ratio of ~10⁵ along with negligible hysteresis.     

The use of “high‐stakes testing” in nursing education: Rhetoric or rigor?

The expectations for clinically ready graduates have increased over the years, paralleling changes in the NCLEX exam with increasingly cognitively difficult items in preparation for professional nursing practice. Yet, it is widely recognized that nursing program exit standardized exams have come under increased scrutiny in several public cases. Several articles have frequently been cited in the opposing argument against use of the HESI Exit Exam or other standardized nursing exit exams. We review two of these for logical coherence and standard psychometric adherence given their recurrent use in arguing against nursing program exit standardized testing. In light of patient safety implications and school accreditation consequences, it's more important that schools use exit standardized testing and assess minimum competency of students based on an exit program standardized exam. Measurement standards are critical to these analyses. The use of a program exit standardized exam also alerts students that faculty are holding them accountable for their time in the program.     

Psychosocial work environment and cross‐cultural competence among native and foreign‐born registered nurses

Cross‐cultural competence is an essential component of the nursing profession, but little is known about the specific psychosocial work characteristics that potentially promote or hinder such competence. In the present study, psychosocial work characteristics were based on Karasek's Job Demand—Control Model. The researchers examined whether Karasek's psychosocial work characteristics, such as high‐strain jobs, high‐strain isolated jobs, active jobs, and active collective jobs, are associated with cross‐cultural competence (empathy, skills, positive attitudes, and motivation), and whether there are differences between native and foreign‐born registered nurses (RN) in these potential associations. A random sample of 744 native RNs (91.0% women) and a total sample (n = 212) of foreign‐born RNs (94.3% women) working in Finland were used. Data were collected using a questionnaire and analyzed with a series of multiple linear regression analyses. High‐strain and high‐strain isolated jobs were negatively associated with all four dimensions of cross‐cultural competence. Active collective jobs, but not active jobs, were positively associated with cross‐cultural skills. There were no differences between native and migrant nurses in these associations. The psychosocial work environment is associated with cross‐cultural competence in both native and migrant nurses. Improvements in psychosocial working conditions, especially minimizing negative factors in the work environment, such as high‐strain and high‐strain isolated jobs, may need to be considered as a part of the efforts aimed to enhance cross‐cultural competence among nursing personnel.     

Sodium-calcium exchange in Purkinje fibers: Electrical and mechanical effects

Summary The role of Na and Ca in the modulation of electrical and mechanical events was studied in canine cardiac Purkinje fibers perfusedin vitro. The results show that: 1) A low Na–Ca solution (Na 80.8 mM, Ca 1.08) increased contractile force and shortened the action potential transiently; during the recovery, the force decreased below and increased transiently above control; the action potential lengthened transiently. 2) A low Na solution increased force and transiently shortened the action potential; during the recovery, the force transiently decreased and the action potential lengthened again. 3) A low Ca solution decreased force and prolonged the action potential; during the recovery, the force increased transiently and the action potential shortened. 4) In low Na–Ca solution, verapamil, manganese or a fast driving rate did not prevent the transient increase in force but in the steady state the force was lower. 5) If the low Na–Ca solution was begun during quiescence resuming activity after one minute already resulted in a higher force. 6) Caffeine and high K decreased force but only caffeine markedly decreased the inotropic effects of low Na. 7) The initial increase in force was reversed in calcium-overloaded fibers. And 8) The Na–Ca ratio necessary to maintain force is smaller for Purkinje than myocardial fibers. It is concluded that a low Na–Ca solution increases force by increasing cellular calcium stores probably in the sarcoplasmic reticulum, that the maintenance of force is critically dependent on a smaller slow inward current, and that there are substantial differences between Purkinje and ventricular muscle fibers.Supported by grants HL17451 and 27038 from the National Institutes of Health, Heart and Lung Institute.During this work Dr. Li was a New York Heart Postdoctoral Fellow. Dr. Li's present address is Searl Research and Development, 4901 Searl Parkway, Skokie, Ill. 60077.     

Ambulatory blood pressure monitoring in the 21st century

In clinical practice, ambulatory blood pressure monitoring (ABPM) tends to be used solely for diagnosing hypertension, especially to identify white‐coat and masked hypertension. However, ABPM can provide additional information to guide the management and drug treatment of hypertension. In this brief review, the general principles governing the use of ABPM in clinical practice, such as the devices and software, recording requirements, the thresholds for the day, night and 24‐hour periods and how often to repeat ABPM are summarized. The use of ABPM for diagnosing, determining the efficacy of treatment, and assessing the long‐term control of hypertension are discussed.     

Abnormal glutathione metabolism and increased cytotoxicity caused by H2O2 in human umbilical vein endothelial cells cultured in high glucose medium

Summary To determine whether increased oxidative stress in diabetes mellitus is due to an impaired freeradical scavenger function in endothelial cells, GSH-dependent H₂O₂ degradation in human umbilical vein endothelial cells was studied. The GSH-dependent, NaN₃-uninhibitable H₂O₂-degradation in endothelial cells was reduced by 48% (p <0.001) when the cells were exposed to 33 mmol/l d-glucose vs 5.5 mmol/l d-glucose. This impairment was dependent not only on the d-glucose concentration in the medium but also on d-glucose specific metabolism, since neither 27.5 mmol/l l-glucose nor 27.5 mmol/l d-raffinose had any effect on the peroxide degradation activity. Activation of the glutathione redox cycle by H₂O₂ in cells exposed to high glucose concentrations was attenuated as compared with 5.5 mmol/l d-glucose because of: 1) a 42% decrease (p <0.001) in intracellular NADPH content, and 2) a 34% reduction (p <0.01) in glutathione release into the media. This results in an accumulation of GSSG in the cells following exposure to H₂O₂. Both H₂O₂-evoked ⁵¹Cr-release and H₂O₂-induced endothelial cell damage were significantly (p <0.01) greater in the 33 mmol/l d-glucose group than in the 5.5 mmol/l d-glucose group. These results indicate that the abnormal glutathione redox cycle observed in endothelial cells is induced by high glucose concentrations in the medium, resulting in an impairment of reduced GSH-dependent H₂O₂-degradation. These abnormalities may associate with the increased cellular damage following an exogenous exposure to H₂O₂.Abbreviations GSH Reduced glutathione - GSSG oxidized glutathione - BSO L-buthionine-[S,R]-sulfoximine