Electrochemical features of Pt(S)[n(110) × (100)] surfaces in acidic media

Experiments have been carried out in sulfuric and perchloric acid solutions on Pt(S)[n(110) × (100)] electrodes. The comparison between the two different electrolytic media reveals an important influence of the anion in the voltammetric features. Total charge curves have been obtained with the CO charge displacement method in combination with voltammetric measurements. From these curves, the dependence of the pztc with the step density and the strength of the anion adsorption have been analyzed. The problem of the so-called third peak is treated for a series of electrodes that contain (110) terraces, revealing the requirement of (110) domains for occurrence of this adsorption state.

Organizational maintenance manual : lathe, engine, bench mounted, solid bed type, 10 inch swing, no. 2 Morse taper center, 1-3/8 spindle hole, 110-volts, 60 cycle, single phase 3/4-horsepower, w/Army dwg. no. 7550151 bench (standard-modern tool series 2,000 model, 11 inch) (3416-517-0955).

"November 1965."

Nd:YAG Laser Improves Biocompatibility of Human Dental Root Surfaces

Objective: Our goal was to compare the in vivo biocompatibility of dental root surfaces submitted to four different treatments after tooth avulsion followed by implantation into rat subcutaneous tissue. Background Data: Dental root surface preparation prior to replanting teeth remains a challenge for endodontists. Root surface changes made by Nd:YAG irradiation could be an alternative preparation. Methods: Forty-eight freshly extracted human dental roots were randomly divided into four treatment groups prior to implantation into rat subcutaneous tissue: G1, dry root, left in the environment up to 3 h; G2, the same treatment as G1, followed by a soaking treatment in a 2.4% sodium fluoride solution (pH 5.5); G3, root soaked in physiologic saline after avulsion for 72 h; G4, the same treatment as G1, followed by Nd:YAG laser irradiation (2.0 W, 20 Hz, 100 mJ, and 124.34 J/cm(2)). The animals were sacrificed 1, 7, and 45 d later. Histological and scanning electron microscopy analyses were done. Results: All dental roots were involved and in intimate contact with connective tissue capsules of variable thicknesses. Differences were observed in the degree of inflammation and in connective tissue maturation. In G3 the inflammatory infiltrate was maintained for 45 d, whereas the Nd:YAG laser irradiation (G4) led to milder responses. The overall aspects of the root surfaces were similar, except by the irradiated roots, where fusion and resolidification of the root surface covering the dentinal tubules were observed. Conclusion: Nd:YAG laser irradiation improves the biocompatibility of dental root and thus could be an alternative treatment of dental root prior to replantation.

Morphologic changes and removal of debris on apical dentin surfaces after Nd : YAG laser and diode laser irradiation

Objective: To verify the effects of laser energy on intracanal dentin surfaces, by analyzing the morphologic changes and removal of debris in the apical third of 30 extracted human teeth, prepared and irradiated with the Nd:YAG laser and diode laser. Background Data: Lasers have been widely used in endodontics. The morphologic changes in dentin walls caused by Nd: YAG and diode laser irradiation could improve apical seals and cleanliness. Materials and Methods: The protocol used for Nd: YAG laser irradiation was 1.5 W, 100 mJ, and 15 Hz, in pulsed mode, and for diode laser was 2.5 W in continuous mode. Each specimen was irradiated four times at a speed of 2 mm/sec with a 20-sec interval between applications. Five calibrated examiners scored the morphologic changes and debris removal on a 4-point scale. Results: In analyzing the scores, there were no statistically significant differences between the two types of laser for either parameter, according to Kruskal-Wallis testing at p = 0.05. The SEM images showed fusion and resolidification of the dentin surface, with partial removal of debris on the specimens irradiated with the Nd: YAG laser and the diode laser, compared with controls. Conclusion: Both lasers promote morphologic changes and debris removal. These alterations of the dentin surface appeared to be more evident in the Nd: YAG laser group, but the diode laser group showed more uniform changes.

Elementary Excitations at Magnetic Surfaces and Their Spin Dependence

The elementary surface excitations are studied by spin-polarized electron energy loss spectroscopy on a prototype oxide surface [an oxygen passivated Fe(001)-p(1 x 1) surface], where the various excitations coexist. For the first time, the surface phonons and magnons are measured simultaneously and are distinguished based on their different spin nature. The dispersion relation of all excitations is probed over the entire Brillouin zone. The different phonon modes observed in our experiment are described by means of ab initio calculations.

Influence of Poly(Vinyl Alcohol) (PVA) on the Cyclic-Voltammetry Behavior of Single-Crystal Pt Surfaces in Aqueous H(2)SO(4)

In the present work we investigated the electrochemical behavior of PVA on polycrystalline Pt and single-crystal Pt electrodes. PVA hampered the characteristic hydrogen UPD and anion adsorption on all investigated surfaces, with the processes on Pt(110) being the most affected by the PVA presence. Several oxidation waves appeared as the potential was swept in the positive direction and the Pt(111) was found to be the most active for the oxidation processes. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3615965] All rights reserved.

Exploring complex fitness surfaces: Multiple ornamentation and polymorphism in male guppies

The sexual ornamentation used by male guppies to attract females comprises many components, each of which varies considerably among males. Although natural and sexual selection have been shown to contribute to divergence among populations in male sexual ornaments, the role of sexual selection in maintaining polymorphism within populations is less clear. We used both parametric quadratic regression and nonparametric projection pursuit regression techniques to reveal the major axes of non-linear sexual selection on male ornaments. We visualized the fitness surfaces defined by these axes using thin-plate splines to allow a direct comparison of the two methodologies. Identification of the major axes of selection and their visualization was critical in determining the form and strength of nonlinear selection. Both types of analysis revealed fitness surfaces comprising three peaks, suggesting that there is more than one way to make an attractive guppy. Disruptive selection may be an important process underlying the presence of multiple sexual ornaments and may contribute to the maintenance of the high levels of polymorphism in male sexual ornaments found in guppy populations.

The effects of clinical support surfaces on pressure as a risk factor in the development of pressure ulcers, from a radiographical perspective: a narrative literature review

Purpose: Pressure ulcers are a high cost, high volume issue for health and medical care providers, having a detrimental effect on patients and relatives. Pressure ulcer prevention is widely covered in the literature, but little has been published regarding the risk to patients in the radiographical setting. This review of the current literature is to identify findings relevant to radiographical context. Methods: Literature searching was performed using Science Direct and Medline databases. The search was limited to articles published in the last ten years to remain current and excluded studies containing participants less than 17 years of age. In total 14 studies were acquired; three were excluded as they were not relevant. The remaining 11 studies were compared and reviewed. Discussion: Eight of the studies used ‘healthy’ participants and three used symptomatic participants. Nine studies explored interface pressure with a range of pressure mat technologies, two studies measured shear (MRI finite element modelling, and a non-invasive instrument), and one looked at blood flow and haemoglobin oxygenation. A range of surfaces were considered from trauma, nursing and surgical backgrounds for their ability to reduce pressure including standard mattresses, high specification mattresses, rigid and soft layer spine boards, various overlays (gel, air filled, foam). Conclusion: The current literature is not appropriate for the radiographic patient and cannot be extrapolated to a radiologic context. Sufficient evidence is presented in this review to support the need for further work specific to radiography in order to minimise the development of PU in at risk patients.

An experimental study to compare the interface pressure and experience of healthy participants when lying still for 20 minutes in a supine position on two different imaging surfaces

Introduction: Pressure ulcers are a high cost, high volume issue for health and medical care providers, affecting patients’ recovery and psychological wellbeing. The current research of support surfaces on pressure as a risk factor in the development of pressure ulcers is not relevant to the specialised, controlled environment of the radiological setting. Method: 38 healthy participants aged 19-51 were placed supine on two different imaging surfaces. The XSENSOR pressure mapping system was used to measure the interface pressure. Data was acquired over a time of 20 minutes preceded by 6 minutes settling time to reduce measurement error. Qualitative information regarding participants’ opinion on pain and comfort was recorded using a questionnaire. Data analysis was performed using SPSS 22. Results: Data was collected from 30 participants aged 19 to 51 (mean 25.77, SD 7.72), BMI from 18.7 to 33.6 (mean 24.12, SD 3.29), for two surfaces, following eight participant exclusions due to technical faults. Total average pressure, average pressure for jeopardy areas (head, sacrum & heels) and peak pressure for jeopardy areas were calculated as interface pressure in mmHg. Qualitative data showed that a significant difference in experiences of comfort and pain was found in the jeopardy areas (P<0.05) between the two surfaces. Conclusion: A significant difference is seen in average pressure between the two surfaces. Pain and comfort data also show a significant difference between the surfaces, both findings support the proposal for further investigation into the effects of radiological surfaces as a risk factor for the formation of pressure ulcers.

Artefacts induced on c-type haem proteins by electrode surfaces

J Biol Inorg Chem (2011) 16:209–215 DOI 10.1007/s00775-010-0717-z

Caracterización de materiales en banda W

Para medir los coeficientes de transmisión y reflexión, S21 y S11, de diferentes materiales o muestras planas, se usa un sistema de toma de medidas en espacio libre operando banda W (75 – 110 GHz). Usando estos parámetros, S21 y S11, podemos calcular la permitividad dieléctrica relativa compleja (Er ) y la permeabilidad magnética relativa compleja (μr) mediante un proceso llamado NRW (Nicolson-Ross-Weir). El sistema para medir consiste en dos antenas de bocina, una transmisora y otra receptora, dos espejos con los que obtenemos una onda plana para medir las propiedades del material y un ordenador o dispositivo que calcula los resultados. Este dispositivo requiere de calibración para la obtención de resultados óptimos. Dicho sistema se puede simular de manera ideal con un software llamado ADS (Assistance Design System) para el estudio y comparación de grosores, permitividades dieléctricas relativas y permeabilidades magnéticas relativas de los materiales en función de la frecuencia.