Chemical etching without acids: from early etching solutions to today's corrosive salts

Conferència impartida a l'Accademia di Belle Arti di Bologna en motiu de de les jornades "Atossico incisione e la sua introduzione in istruzione superiore", del 25 al 27 de gener del 2011 a Bologna

Optimal and continuous anaemia control in a cohort of dialysis patients in Switzerland.

BACKGROUND: Guidelines for the management of anaemia in patients with chronic kidney disease (CKD) recommend a minimal haemoglobin (Hb) target of 11 g/dL. Recent surveys indicate that this requirement is not met in many patients in Europe. In most studies, Hb is only assessed over a short-term period. The aim of this study was to examine the control of anaemia over a continuous long-term period in Switzerland. METHODS: A prospective multi-centre observational study was conducted in dialysed patients treated with recombinant human epoetin (EPO) beta, over a one-year follow-up period, with monthly assessments of anaemia parameters. RESULTS: Three hundred and fifty patients from 27 centres, representing 14% of the dialysis population in Switzerland, were included. Mean Hb was 11.9 +/- 1.0 g/dL, and remained stable over time. Eighty-five % of the patients achieved mean Hb >or= 11 g/dL. Mean EPO dose was 155 +/- 118 IU/kg/week, being delivered mostly by subcutaneous route (64-71%). Mean serum ferritin and transferrin saturation were 435 +/- 253 microg/L and 30 +/- 11%, respectively. At month 12, adequate iron stores were found in 72.5% of patients, whereas absolute and functional iron deficiencies were observed in only 5.1% and 17.8%, respectively. Multivariate analysis showed that diabetes unexpectedly influenced Hb towards higher levels (12.1 +/- 0.9 g/dL; p = 0.02). One year survival was significantly higher in patients with Hb >or= 11 g/dL than in those with Hb <11 g/dL (19.7% vs 7.3%, p = 0.006). CONCLUSION: In comparison to European studies of reference, this survey shows a remarkable and continuous control of anaemia in Swiss dialysis centres. These results were reached through moderately high EPO doses, mostly given subcutaneously, and careful iron therapy management.

How Much Does It Cost? Optimization of Costs in Sequence Analysis of Social Science Data

One major methodological problem in analysis of sequence data is the determination of costs from which distances between sequences are derived. Although this problem is currently not optimally dealt with in the social sciences, it has some similarity with problems that have been solved in bioinformatics for three decades. In this article, the authors propose an optimization of substitution and deletion/insertion costs based on computational methods. The authors provide an empirical way of determining costs for cases, frequent in the social sciences, in which theory does not clearly promote one cost scheme over another. Using three distinct data sets, the authors tested the distances and cluster solutions produced by the new cost scheme in comparison with solutions based on cost schemes associated with other research strategies. The proposed method performs well compared with other cost-setting strategies, while it alleviates the justification problem of cost schemes.

Evidence-Based Recommendations for Optimal Dietary Protein Intake in Older People: A Position Paper From the PROT-AGE Study Group.

New evidence shows that older adults need more dietary protein than do younger adults to support good health, promote recovery from illness, and maintain functionality. Older people need to make up for age-related changes in protein metabolism, such as high splanchnic extraction and declining anabolic responses to ingested protein. They also need more protein to offset inflammatory and catabolic conditions associated with chronic and acute diseases that occur commonly with aging. With the goal of developing updated, evidence-based recommendations for optimal protein intake by older people, the European Union Geriatric Medicine Society (EUGMS), in cooperation with other scientific organizations, appointed an international study group to review dietary protein needs with aging (PROT-AGE Study Group). To help older people (>65 years) maintain and regain lean body mass and function, the PROT-AGE study group recommends average daily intake at least in the range of 1.0 to 1.2 g protein per kilogram of body weight per day. Both endurance- and resistance-type exercises are recommended at individualized levels that are safe and tolerated, and higher protein intake (ie, ≥1.2 g/kg body weight/d) is advised for those who are exercising and otherwise active. Most older adults who have acute or chronic diseases need even more dietary protein (ie, 1.2-1.5 g/kg body weight/d). Older people with severe kidney disease (ie, estimated GFR <30 mL/min/1.73m(2)), but who are not on dialysis, are an exception to this rule; these individuals may need to limit protein intake. Protein quality, timing of ingestion, and intake of other nutritional supplements may be relevant, but evidence is not yet sufficient to support specific recommendations. Older people are vulnerable to losses in physical function capacity, and such losses predict loss of independence, falls, and even mortality. Thus, future studies aimed at pinpointing optimal protein intake in specific populations of older people need to include measures of physical function.

Optimal dividend strategies for a compound Poisson risk process under transaction costs and power utility

We characterize the value function of maximizing the total discounted utility of dividend payments for a compound Poisson insurance risk model when strictly positive transaction costs are included, leading to an impulse control problem. We illustrate that well known simple strategies can be optimal in the case of exponential claim amounts. Finally we develop a numerical procedure to deal with general claim amount distributions.

Shear thinning and thixotropy of HMHEC and HEC water solutions

Steady state viscosity and thixotropy of hydrophobically modified hydroxyethyl cellulose HMHEC and nonassociative cellulose water solutions are studied. Although all the samples are shear thinning, only the HMHEC is thixotropic, since the migration of hydrophobes to micelles is controlled by diffusion. The Cross model fits steady state curves. The Mewis model, a phenomenological model that proposes that the rate of change of viscosity when the shear rate is suddenly changed is related to the difference between the steady state and current values of viscosity raised to an exponent, fits structure construction experiments when the exponent, n, is estimated to be around 2. The Newtonian assumption used by Mewis cannot be used here, however. This seems to be related to the fact that the thickening is due to bridged micelle formation, which is a slow process, and also to topological constraints and entanglements, which are rapid processes. The kinetic parameter was redefined to kn in order to make it independent of initial conditions. So, kn depends only on how the shear affects the structure. kn reaches a plateau at shear rates too low to produce structure destruction and decreases at higher shear rates.

Innovative Solutions for Slope Stability Reinforcement and Characterization: Vol. I, TR-489, 2005

Soil slope instability concerning highway infrastructure is an ongoing problem in Iowa, as slope failures endanger public safety and continue to result in costly repair work. Characterization of slope failures is complicated, because the factors affecting slope stability can be difficult to discern and measure, particularly soil shear strength parameters. While in the past extensive research has been conducted on slope stability investigations and analysis, this research consists of field investigations addressing both the characterization and reinforcement of such slope failures. The current research focuses on applying an infrequently-used testing technique comprised of the Borehole Shear Test (BST). This in-situ test rapidly provides effective (i.e., drained) shear strength parameter values of soil. Using the BST device, fifteen Iowa slopes (fourteen failures and one proposed slope) were investigated and documented. Particular attention was paid to highly weathered shale and glacial till soil deposits, which have both been associated with slope failures in the southern Iowa drift region. Conventional laboratory tests including direct shear tests, triaxial compression tests, and ring shear tests were also performed on undisturbed and reconstituted soil samples to supplement BST results. The shear strength measurements were incorporated into complete evaluations of slope stability using both limit equilibrium and probabilistic analyses. The research methods and findings of these investigations are summarized in Volume 1 of this report. Research details of the independent characterization and reinforcement investigations are provided in Volumes 2 and 3, respectively. Combined, the field investigations offer guidance on identifying the factors that affect slope stability at a particular location and also on designing slope reinforcement using pile elements for cases where remedial measures are necessary. The research findings are expected to benefit civil and geotechnical engineers of government transportation agencies, consultants, and contractors dealing with slope stability, slope remediation, and geotechnical testing in Iowa.

Innovative Solutions for Slope Stability Reinforcement and Characterization: Vol. II, TR-489, 2005

Soil slope instability concerning highway infrastructure is an ongoing problem in Iowa, as slope failures endanger public safety and continue to result in costly repair work. While in the past extensive research has been conducted on slope stability investigations and analysis, this current research study consists of field investigations addressing both the characterization and reinforcement of such slope failures. While Volume I summarizes the research methods and findings of this study, Volume II provides procedural details for incorporating an infrequently-used testing technique, borehole shear tests, into practice. Fifteen slopes along Iowa highways were investigated, including thirteen slides (failed slopes), one unfailed slope, and one proposed embankment slope (the Sugar Creek Project). The slopes are mainly comprised of either clay shale or glacial till, and are generally gentle and of small scale, with slope angle ranging from 11 deg to 23 deg and height ranging from 6 to 23 m. Extensive field investigations and laboratory tests were performed for each slope. Field investigations included survey of slope geometry, borehole drilling, soil sampling, in-situ Borehole Shear Testing (BST) and ground water table measurement. Laboratory investigations mainly comprised of ring shear tests, soil basic property tests (grain size analysis and Atterberg limits test), mineralogy analyses, soil classifications, and natural water contents and density measurements on the representative soil samples from each slope. Extensive direct shear tests and a few triaxial compression tests and unconfined compression tests were also performed on undisturbed soil samples for the Sugar Creek Project. Based on the results of field and lab investigations, slope stability analysis was performed on each of the slopes to determine the possible factors resulting in the slope failures or to evaluate the potential slope instabilities using limit equilibrium methods. Deterministic slope analyses were performed for all the slopes. Probabilistic slope analysis and sensitivity study were also performed for the slope of the Sugar Creek Project. Results indicate that while the in-situ test rapidly provides effective shear strength parameters of soils, some training may be required for effective and appropriate use of the BST. Also, it is primarily intended to test cohesive soils and can produce erroneous results in gravelly soils. Additionally, the quality of boreholes affects test results, and disturbance to borehole walls should be minimized before test performance. A final limitation of widespread borehole shear testing may be its limited availability, as only about four to six test devices are currently being used in Iowa. Based on the data gathered in the field testing, reinforcement investigations are continued in Volume III.

Innovative Solutions for Slope Stability Reinforcement and Characterization: Vol. III, TR-489, 2005

Soil slope instability concerning highway infrastructure is an ongoing problem in Iowa, as slope failures endanger public safety and continue to result in costly repair work. Volume I of this current study summarizes research methods and findings, while Volume II provides procedural details for incorporating into practice an infrequently-used testing technique–borehole shear tests. Volume III of this study of field investigation of fifteen slopes in Iowa demonstrates through further experimental testing how lateral forces develop along stabilizing piles to resist slope movements. Results establish the feasibility of an alternative stabilization approach utilizing small-diameter pile elements. Also, a step-by-step procedure that can be used by both state and county transportation agencies to design slope reinforcement using slender piles is documented. Initial evidence of the efficiency and cost-effectiveness of stabilizing nuisance slope failures with grouted micropiles is presented. Employment of the remediation alternative is deemed more appropriate for stabilizing shallow slope failures. Overall, work accomplished in this research study included completing a comprehensive literature review on the state of the knowledge of slope stability and slope stabilization, the preparation and performance of fourteen full-scale pile load tests, the analysis of load test results, and the documentation of a design methodology for implementing the technology into current practices of slope stabilization. Recommendations for further research include monitoring pilot studies of slope reinforcement with grouted micropiles, supplementary experimental studies, and advanced numerical studies.