Surface modification of polyacrylonitrile staple fibers via alkaline hydrolysis for superabsorbent applications

The alkaline hydrolysis of polyacrylonitrile staple fibers was investigated for evaluation as superabsorbent materials. Studies were performed to analyze the hydrolysis of fibers and the quantification of the developed functional groups, such as carboxyl and amide groups as well as changes in the nitrile content by means of Micro‐ATR. Dyeing of the samples with methylene blue was carried out to monitor the carboxyl groups formed during the hydrolysis. A gradual decrease in the nitrile groups and built up of the carboxyl and the amide groups was observed during the hydrolysis. Microscopic investigation carried out to investigate the surface structure of hydrolyzed fibers. Hydrolysis led to surface nonhomogeneity and erosion that was dependent on the hydrolysis conditions. The fibers showed good water retention behavior, making them superabsorbent materials. The dyeing showed more intense coloration in the surface region of the modified fibers. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3127–3133, 2004     

Probability effects on stimulus evaluation and response processes.

Investigated the effects of probability information on response preparation and stimulus evaluation. Eight Ss responded with 1 hand to the target letter H and with the other to the target letter S. The target letter was surrounded by noise letters that were either the same as or different from the target letter. In 2 conditions, the targets were preceded by a warning stimulus unrelated to the target letter. In 2 other conditions, a warning letter predicted that the same letter or the opposite letter would appear as the imperative stimulus with .80 probability. Correct reactions times (RTs) were faster and error rates were lower when imperative stimuli confirmed the predictions of the warning stimulus. Probability information affected (1) the preparation of motor responses during the foreperiod, (2) the development of expectancies for a particular target letter, and (3) a process sensitive to the identities of letter stimuli but not to their locations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The learning of generalized motor programs: Reducing the relative frequency of knowledge of results enhances memory.

In earlier studies, reducing the relative frequency of knowledge of results (KR) enhanced retention of single movements. In the experiments here we asked whether this variable also enhances memory for classes of actions governed by generalized motor programs. Acquisition conditions involved practicing three versions of a sequential timing task. All three versions had the same temporal structure (or phasing), but the overall durations were different. KR was presented on either 100% or 67% of the trials for two groups. In Experiment 1, reduced relative KR frequency, spread equally across all task versions, enhanced accuracy of the learned relative timing structure as measured on a transfer test with a novel movement duration. Experiment 2 showed that retention of a medium-duration version was more accurate for subjects who never received KR about it in acquisition, as compared with subjects who always did. The data support the view that reduced KR frequency enhances acquisition of the relative-timing structure underlying memory for a class of actions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Synthesis and Biological Evaluation of Papain‐Family Cathepsin L‐Like Cysteine Protease Inhibitors Containing a 1,4‐Benzodiazepine Scaffold as Antiprotozoal Agents

Novel papain‐family cathepsin L‐like cysteine protease inhibitors endowed with antitrypanosomal and antimalarial activity were developed, through an optimization study of previously developed inhibitors. In the present work, we studied the structure–activity relationships of these derivatives, with the aim to develop new analogues with a simplified and more synthetically accessible structure and with improved antiparasitic activity. The structure of the model compounds was significantly simplified by modifying or even eliminating the side chain appended at the C3 atom of the benzodiazepine scaffold. In addition, a simple methylene spacer of appropriate length was inserted between the benzodiazepine ring and the 3‐bromoisoxazoline moiety. Several rhodesain and falcipain‐2 inhibitors displaying single‐digit micromolar or sub‐micromolar antiparasitic activity against one or both parasites were identified, with activities that were one order of magnitude more potent than the model compounds.     

Latent risk and trend models for the evolution of annual fatality numbers in 30 European countries

In this paper a unified methodology is presented for the modelling of the evolution of road safety in 30 European countries. For each country, annual data of the best available exposure indicator and of the number of fatalities were simultaneously analysed with the bivariate latent risk time series model. This model is based on the assumption that the amount of exposure and the number of fatalities are intrinsically related. It captures the dynamic evolution in the fatalities as the product of the dynamic evolution in two latent trends: the trend in the fatality risk and the trend in the exposure to that risk. Before applying the latent risk model to the different countries it was first investigated and tested whether the exposure indicator at hand and the fatalities in each country were in fact related at all. If they were, the latent risk model was applied to that country; if not, a univariate local linear trend model was applied to the fatalities series only, unless the latent risk time series model was found to yield better forecasts than the univariate local linear trend model. In either case, the temporal structure of the unobserved components of the optimal model was established, and structural breaks in the trends related to external events were identified and captured by adding intervention variables to the appropriate components of the model. As a final step, for each country the optimally modelled developments were projected into the future, thus yielding forecasts for the number of fatalities up to and including 2020.     

Digital image correlation techniques to investigate strain fields and cracking phenomena in asphalt materials

This paper is the outcome of a specific task group of the RILEM Technical Committee 241-MCD “Mechanisms of Cracking and Debonding in Asphalt and Composite Pavements”. The group on “Advanced Measurement Techniques” was established in 2011 to investigate DIC applications for non-destructive and non-contact measurements of strain fields during laboratory testing. The paper illustrates different DIC/optical flow applications in measuring strain distribution during laboratory testing. Specific applications of DIC for evaluating crack initiation and crack propagation in asphalt materials are presented.     

Radon in workplaces: first results of an extensive survey and comparison with radon in homes

Extensive radon surveys have been carried out in many countries only in dwellings, whereas surveys in workplaces are rather sparse and generally restricted to specific workplaces/activities, e.g. schools, spas and caves. Moreover, radon-prone areas are generally defined on the basis of radon surveys in dwellings, while radon regulations use this concept to introduce specific requirements in workplaces in such areas. This approach does not take into account that work activities and workplace characteristics can significantly affect radon concentration. Therefore, an extensive survey on radon in different workplaces have been carried out in a large region of Italy (Tuscany), in order to evaluate radon distribution in workplaces over the whole territory and to identify activities and workplace characteristics affecting radon concentration. The results of this extensive survey are compared with the results of the survey carried out in dwellings in the same period. The workplaces monitored were randomly selected among the main work activities in the region, including both public and industrial buildings. The survey monitored over 3500 rooms in more than 1200 buildings for two consecutive periods of ～6 months. Radon concentration was measured by means of passive nuclear track detectors.     

Wavelet transforms to probe long- and short-range forces by thermally excited dynamic force spectroscopy

The use of wavelet transforms in thermally excited dynamic force spectroscopy allows us to gain insight into the fundamental thermodynamical properties of a cantilever's Brownian motion as well as giving a meaningful and intuitive representation of the cantilever dynamics in time and frequency caused by the interaction with long- and short-range forces. The possibility of carrying out measurements across the jump-to-contact transition without interruption, providing information on both van der Waals forces and short-range adhesion surface forces, is remarkable.