Effects of mechanical properties, residual stress and indenter tip geometry on instrumented indentation data in thin films

In this work, an axisymmetric two-dimensional finite element model was developed to simulate instrumented indentation testing of thin ceramic films deposited onto hard steel substrates. The level of film residual stress (sigma(r)), the film elastic modulus (E) and the film work hardening exponent (n) were varied to analyze their effects on indentation data. These numerical results were used to analyze experimental data that were obtained with titanium nitride coated specimens, in which the substrate bias applied during deposition was modified to obtain films with different levels of sigma(r). Good qualitative correlation was obtained when numerical and experimental results were compared, as long as all film properties are considered in the analyses, and not only sigma(r). The numerical analyses were also used to further understand the effect of sigma(r) on the mechanical properties calculated based on instrumented indentation data. In this case, the hardness values obtained based on real or calculated contact areas are similar only when sink-in occurs, i.e. with high n or high ratio VIE, where Y is the yield strength of the film. In an additional analysis, four ratios (R/h(max)) between indenter tip radius and maximum penetration depth were simulated to analyze the combined effects of R and sigma(r) on the indentation load-displacement curves. In this case, or did not significantly affect the load curve exponent, which was affected only by the indenter tip radius. On the other hand, the proportional curvature coefficient was significantly affected by sigma(r) and n. (C) 2010 Elsevier B.V. All rights reserved.

Numerical study of tensile tests conducted on systems with elastic-plastic films deposited onto elastic-plastic substrates

In this work, a series of two-dimensional plane-strain finite element analyses was conducted to further understand the stress distribution during tensile tests on coated systems. Besides the film and the substrate, the finite element model also considered a number of cracks perpendicular to the film/substrate interface. Different from analyses commonly found in the literature, the mechanical behavior of both film and substrate was considered elastic-perfectly plastic in part of the analyses. Together with the film yield stress and the number of film cracks, other variables that were considered were crack tip geometry, the distance between two consecutive cracks and the presence of an interlayer. The analysis was based on the normal stresses parallel to the loading axis (sigma(xx)), which are responsible for cohesive failures that are observed in the film during this type of test. Results indicated that some configurations studied in this work have significantly reduced the value of sigma(xx) at the film/substrate interface and close to the pre-defined crack tips. Furthermore, in all the cases studied the values of sigma(xx) were systematically larger at the film/substrate interface than at the film surface. (C) 2010 Elsevier B.V. All rights reserved.

Thin titanium oxide films deposited by e-beam evaporation with additional rapid thermal oxidation and annealing for ISFET applications

Titanium oxide (TiO(2)) has been extensively applied in the medical area due to its proved biocompatibility with human cells [1]. This work presents the characterization of titanium oxide thin films as a potential dielectric to be applied in ion sensitive field-effect transistors. The films were obtained by rapid thermal oxidation and annealing (at 300, 600, 960 and 1200 degrees C) of thin titanium films of different thicknesses (5 nm, 10 nm and 20 nm) deposited by e-beam evaporation on silicon wafers. These films were analyzed as-deposited and after annealing in forming gas for 25 min by Ellipsometry, Fourier Transform Infrared Spectroscopy (FTIR), Raman Spectroscopy (RAMAN), Atomic Force Microscopy (AFM), Rutherford Backscattering Spectroscopy (RBS) and Ti-K edge X-ray Absorption Near Edge Structure (XANES). Thin film thickness, roughness, surface grain sizes, refractive indexes and oxygen concentration depend on the oxidation and annealing temperature. Structural characterization showed mainly presence of the crystalline rutile phase, however, other oxides such Ti(2)O(3), an interfacial SiO(2) layer between the dielectric and the substrate and the anatase crystalline phase of TiO(2) films were also identified. Electrical characteristics were obtained by means of I-V and C-V measured curves of Al/Si/TiO(x)/Al capacitors. These curves showed that the films had high dielectric constants between 12 and 33, interface charge density of about 10(10)/cm(2) and leakage current density between 1 and 10(-4) A/cm(2). Field-effect transistors were fabricated in order to analyze I(D) x V(DS) and log I(D) x Bias curves. Early voltage value of -1629 V, R(OUT) value of 215 M Omega and slope of 100 mV/dec were determined for the 20 nm TiO(x) film thermally treated at 960 degrees C. (C) 2009 Elsevier B.V. All rights reserved.

Economic design of an X chart for short-run production

The aim of this paper is to present an economical design of an X chart for a short-run production. The process mean starts equal to mu(0) (in-control, State I) and in a random time it shifts to mu(1) > mu(0) (out-of-control, State II). The monitoring procedure consists of inspecting a single item at every m produced ones. If the measurement of the quality characteristic does not meet the control limits, the process is stopped, adjusted, and additional (r - 1) items are inspected retrospectively. The probabilistic model was developed considering only shifts in the process mean. A direct search technique is applied to find the optimum parameters which minimizes the expected cost function. Numerical examples illustrate the proposed procedure. (C) 2009 Elsevier B.V. All rights reserved.

NEW PHYTOSEIIDAE (ACARI: MESOSTIGMATA) FROM COSTA RICA, WITH ADDITIONAL INFORMATION ON OTHER SPECIES

This paper reports on a study of phytoseiids collected from the La Selva Biological Field Station, the ALAS (Arthropods of La Selva) Project, made available to us by the Canadian National Collection via Dr. E. E. Lindquist. This material includes two new species, Proprioseiopsis versus n. sp. and Transeius costarricensis n. sp., three new records for Central America, and additional information for nine species previously reported from La Selva.

Spatial portability of numerical models of leaf wetness duration based on empirical approaches

Leaf wetness duration (LWD) models based on empirical approaches offer practical advantages over physically based models in agricultural applications, but their spatial portability is questionable because they may be biased to the climatic conditions under which they were developed. In our study, spatial portability of three LWD models with empirical characteristics - a RH threshold model, a decision tree model with wind speed correction, and a fuzzy logic model - was evaluated using weather data collected in Brazil, Canada, Costa Rica, Italy and the USA. The fuzzy logic model was more accurate than the other models in estimating LWD measured by painted leaf wetness sensors. The fraction of correct estimates for the fuzzy logic model was greater (0.87) than for the other models (0.85-0.86) across 28 sites where painted sensors were installed, and the degree of agreement k statistic between the model and painted sensors was greater for the fuzzy logic model (0.71) than that for the other models (0.64-0.66). Values of the k statistic for the fuzzy logic model were also less variable across sites than those of the other models. When model estimates were compared with measurements from unpainted leaf wetness sensors, the fuzzy logic model had less mean absolute error (2.5 h day(-1)) than other models (2.6-2.7 h day(-1)) after the model was calibrated for the unpainted sensors. The results suggest that the fuzzy logic model has greater spatial portability than the other models evaluated and merits further validation in comparison with physical models under a wider range of climate conditions. (C) 2010 Elsevier B.V. All rights reserved.

Root Water Extraction under Combined Water and Osmotic Stress

Using a numerical implicit model for root water extraction by a single root in a symmetric radial flow problem, based on the Richards equation and the combined convection-dispersion equation, we investigated some aspects of the response of root water uptake to combined water and osmotic stress. The model implicitly incorporates the effect of simultaneous pressure head and osmotic head on root water uptake, and does not require additional assumptions (additive or multiplicative) to derive the combined effect of water and salt stress. Simulation results showed that relative transpiration equals relative matric flux potential, which is defined as the matric flux potential calculated with an osmotic pressure head-dependent lower bound of integration, divided by the matric flux potential at the onset of limiting hydraulic conditions. In the falling rate phase, the osmotic head near the root surface was shown to increase in time due to decreasing root water extraction rates, causing a more gradual decline of relative transpiration than with water stress alone. Results furthermore show that osmotic stress effects on uptake depend on pressure head or water content, allowing a refinement of the approach in which fixed reduction factors based on the electrical conductivity of the saturated soil solution extract are used. One of the consequences is that osmotic stress is predicted to occur in situations not predicted by the saturation extract analysis approach. It is also shown that this way of combining salinity and water as stressors yields results that are different from a purely multiplicative approach. An analytical steady state solution is presented to calculate the solute content at the root surface, and compared with the outputs of the numerical model. Using the analytical solution, a method has been developed to estimate relative transpiration as a function of system parameters, which are often already used in vadose zone models: potential transpiration rate, root length density, minimum root surface pressure head, and soil theta-h and K-h functions.

Process Capability Indexes Determination on Tabletting Performance during the Process Validation for Metamizol Tablets

The aim of the present study was to provide a numerical measure, through the process capability indexes (PCIs), C(p) and C(pk), on whether or not the manufacturing process can be considered capable of producing metamizol (500 mg) tablets. They were also used as statistical tool in order to prove the consistency of the tabletting process, making sure that the tablet weight and the content uniformity of metamizol are able to comply with the preset requirements. Besides that, the ANOVA, the t-test and the test for equal variances were applied to this study, allowing additional knowledge of the tabletting phase. Therefore, the proposed statistical approach intended to assure more safety, precision and accuracy on the process validation analysis.

Evaluation of the antioxidant activity as an additional parameter to attain the functional quality of natural extracts

Due to differences in the functional quality of natural extracts, we have also faced differences in their effectiveness. So, it was intended to assess the antioxidant activity of natural extracts in order to attain their functional quality. It was observed that all the extracts (brown and green propolis, Ginkgo biloba and Isoflavin Beta (R)) and the standard used (quercetin) showed antioxidant activity in a dose-dependent manner with IC50 values ranging from 0.21 to 155.28 mu g mL(-1) (inhibition of lipid peroxidation and scavenging of the DPPH center dot assays). We observed a high correlation (r(2)= 0.9913) among the antioxidant methods; on the other hand, the antioxidant activity was not related to the polyphenol and flavonoid content. As the DPPH center dot assay is a fast method, presents low costs and even has a high correlation with other antioxidant methods, it could be applied as an additional parameter in the quality control of natural extracts.

Increasing the Rates of Complete Response to Neoadjuvant Chemoradiotherapy for Distal Rectal Cancer: Results of a Prospective Study Using Additional Chemotherapy During the Resting Period

OBJECTIVES: Addition of chemotherapy in the resting period between radiotherapy completion and response assessment during neoadjuvant treatment for distal rectal cancer could potentially increase rates of complete tumor regression. The purpose of this study was to evaluate toxicity rates and the impact of an extended neoadjuvant chemoradiation regimen on complete response rates. METHODS: Thirty-four consecutive patients with nonmetastatic distal rectal cancer were prospectively included. Patients were managed by 5,400 Gy of radiation and 5-fluorouracil/leucovorin-based chemotherapy given for three consecutive days every 21 days for six cycles (three cycles concomitant with radiotherapy). Tumor response assessment was performed at ten weeks from radiation completion. Patients with complete clinical response were strictly monitored and were not immediately operated on. Patients with incomplete clinical response were referred to surgery. RESULTS: Twenty-nine patients had completed 12 months of follow-up and were included in this preliminary analysis. Twenty-eight (97%) successfully completed treatment. Fifteen of 16 patients had Grade III toxicities that were skin-related (93%). Median follow-up was 23 months. Fourteen patients (48%) were considered as complete clinical responders sustained for at least 12 months (median, 24 months) after chemoradiation completion by clinical assessment alone. An additional five patients (17%) were considered as complete responders with ypT0 results after full-thickness local excision. Overall, the complete response rate was 65%. CONCLUSIONS: The addition of chemotherapy during the resting period after neoadjuvant chemoradiation is associated with acceptable toxicity and high tolerability rates. The considerably high rates of complete response in this preliminary series requires further follow-up, but they may provide valuable information for future prospective, randomized trials.

Direct measurement of instantaneous source speed for a HDR brachytherapy unit using an optical fiber based detector

Purpose: Several attempts to determine the transit time of a high dose rate (HDR) brachytherapy unit have been reported in the literature with controversial results. The determination of the source speed is necessary to accurately calculate the transient dose in brachytherapy treatments. In these studies, only the average speed of the source was measured as a parameter for transit dose calculation, which does not account for the realistic movement of the source, and is therefore inaccurate for numerical simulations. The purpose of this work is to report the implementation and technical design of an optical fiber based detector to directly measure the instantaneous speed profile of a (192)Ir source in a Nucletron HDR brachytherapy unit. Methods: To accomplish this task, we have developed a setup that uses the Cerenkov light induced in optical fibers as a detection signal for the radiation source moving inside the HDR catheter. As the (192)Ir source travels between two optical fibers with known distance, the threshold of the induced signals are used to extract the transit time and thus the velocity. The high resolution of the detector enables the measurement of the transit time at short separation distance of the fibers, providing the instantaneous speed. Results: Accurate and high resolution speed profiles of the 192Ir radiation source traveling from the safe to the end of the catheter and between dwell positions are presented. The maximum and minimum velocities of the source were found to be 52.0 +/- 1.0 and 17.3 +/- 1:2 cm/s. The authors demonstrate that the radiation source follows a uniformly accelerated linear motion with acceleration of vertical bar a vertical bar = 113 cm/s(2). In addition, the authors compare the average speed measured using the optical fiber detector to those obtained in the literature, showing deviation up to 265%. Conclusions: To the best of the authors` knowledge, the authors directly measured for the first time the instantaneous speed profile of a radiation source in a HDR brachytherapy unit traveling from the unit safe to the end of the catheter and between interdwell distances. The method is feasible and accurate to implement on quality assurance tests and provides a unique database for efficient computational simulations of the transient dose. (C) 2010 American Association of Physicists in Medicine. [DOI: 10.1118/1.3483780]

Group psychotherapy: An additional approach to burning mouth syndrome

Introduction: Glossodynia or burning mouth syndrome (BMS) is a common and poorly understood disorder. Its treatment is uncertain. Otherwise, there is some evidence of the importance of psychological factors in the genesis of this disease. Objectives: Verify the usefulness of group psychotherapy as an adjuvant therapeutic method in the treatment of BMS. Casuistics and Methods: The study group consisted of 64 consecutive patients with a clinical diagnosis of BMS seen at the Stomatology Outpatient Clinic, ENT Department, Sao Paulo University Medical School, between May 2002 and May 2007. All the patients were submitted to physical examination, laboratorial screening tests, psychological assessment (Crown-Crisp Experimental Inventory), and answered a short form of the McGill Pain Questionnaire. Only 44 patients who did not show any abnormality in the protocol exams entered the study. Twenty-four of them underwent group psychotherapy. Twenty patients received placebo. Chi-square test was applied to compare the results of treatment with or without psychotherapy. Results: There were 15 men and 29 women in the study group. Tongue burning was the main complaint of the patients. Improvement of symptoms was reported by 17 (70.8%) of the patients undergoing psychotherapy, while among those who did not eight (40%) had improvement of symptoms (P=.04). Conclusion: Psychological assessment demonstrated a close correlation between symptoms and psychological factors, suggesting that group psychotherapy is an important alternative to conventional treatment methods. (C) 2009 Elsevier Inc. All rights reserved.

Additional sensory information reduces body sway of individuals with anterior cruciate ligament injury

The purpose of this study was to investigate whether the additional sensory information could improve postural control in individuals with unilateral anterior cruciate ligament (ACL) injury. Twenty-eight individuals with unilateral ACL injury (mean age 23.6, 26 males, 2 females) and 28 healthy young control subjects (mean age 22.1 years, 26 males, 2 females) participated in this study. Postural control was evaluated with subjects single-leg standing on a force platform with eyes closed under two sensory conditions: normal sensory information and light touch to a stationary bar (applied force below 1 N). Three trials of 30 5 were performed in each single-leg stance and in each sensory condition. Mean sway amplitude and predominant frequency of center of pressure were calculated for both anterior-posterior and medial-lateral directions. Individuals with ACL injury showed greater mean sway amplitude than healthy control individuals even though the predominant frequency was similar for both groups. Additional sensory information improved postural control performance in individuals with ACL injury and healthy control, with a greater effect observed for the ACL group. Based on these results, we suggest that reduction in postural control performance in individuals with ACL injury would be due to the reduction of sensory information provided by the ACL, but when sensory information is enhanced, postural control performance improves. These results have implications for novel approaches to improve stability in individuals with ACL injury. (c) 2008 Elsevier Ireland Ltd. All rights reserved.

Influence of the Additional Er:YAG Laser Conditioning Step on the Microleakage of Class V Restorations

The purpose of this study was to evaluate the influence of an additional Er:YAG laser conditioning step after laser cavity preparations, on the microleakage of class V composite restorations. Forty-eight bovine incisors were randomly divided into four groups: G1(control) cavities prepared with bur, G2- cavities prepared with laser (400 mJ/2 Hz), G3-cavities prepared and subsequently conditioned with Er:YAG laser (60 mJ/2 Hz); G4-idem for G3, but the laser conditioning was carried out without water-spray. All the cavities were restored using Clearfill SE Bond (R) and Z-250 (R) composite resin. The samples were thermal cycled for 700 cycles and then immersed in 50% silver nitrate solution. The sectioned restorations were exposed to a photoflood lamp to reveal silver nitrate penetration. The Kruskal-Walis one-way analyses of variance test and post hoc Wilcoxon pair-wise comparison were used to compare microleakage degrees. At the gingival margin G2 showed a lower microleakage mean than the control bur-prepared cavities (p = 0.0003). At occlusal margins there were no statistically significant differences between the groups (p = 0.28). It may be concluded that Er:YAG laser class V cavity preparations do not need to be followed by an additional laser conditioning step to result in levels of microleakage similar to or lower than those obtained after bur preparations. (C) 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 87B: 538-543, 2008

Characterisation of additional mental foramina through cone beam computed tomography

Variations in jaw bone neurovascularisation must be identified to decrease the potential risk for haemorrhages and neural disturbances during surgical procedures such as implant placement and orthognatic surgeries. The aim of this study is to characterise additional mental foramina (AMF) through cone beam computed tomography (CBCT) images, by describing their frequency, size, location and direction of their associated bony canals, as well as to assess their corresponding ipsilateral and contralateral mental foramina (MF). CBCT images from 285 patients were analysed. Prevalence of AMF was 9.4%. From 0 to 2 AMF were observed, with two bilateral cases. Two cases of unilateral absence of MF were registered. Patients presenting AMF did not differ significantly from those without AMF regarding gender, age or ethnicity. Diameters of AMF and their corresponding ipsilateral and contralateral MF were 1.9 mm (+/- 0.7 mm), 3.8 mm (+/- 0.6 mm) and 4.1 mm (+/- 0.6 mm), respectively. Ratios between diameters of AMF and corresponding ipsilateral MF ranged between 0.24 and 0.99. Location of AMF was variable, with most cases located posteriorly, posterior-inferiorly, posterior-superiorly or anterior-superiorly to their respective MF. Significant anatomical variability regarding neurovascularisation was observed among patients and CBCT examinations presented as a valuable tool for individually assessing these anatomical features.