Laser-Induced Creation of Antiferromagnetic 180-Degree Domains in NiO/Pt Bilayers

The antiferromagnetic order in heterostructures of NiO/Pt thin films can be modified by optical pulses. After the irradiation with laser light, the optically induced creation of antiferromagnetic domains can be observed by imaging the created domain structure utilizing the X-ray magnetic linear dichroism effect. The effect of different laser polarizations on the domain formation can be studied and used to identify a polarization-independent creation of 180° domain walls and domains with 180° different Néel vector orientation. By varying the irradiation parameters, the switching mechanism can be determined to be thermally induced. This study demonstrates experimentally the possibility to optically create antiferromagnetic domains, an important step towards future functionalization of all optical switching mechanisms in antiferromagnets.     

The "If only I were thin…" Treatment Program: Decreasing the stigmatizing effects of fatness.

The authors describe an innovative treatment program for fat women designed to increase the number and variety of their daily activities and decrease their fat phobic attitudes and depression, thereby increasing their self-esteem. Data on 47 female clients who completed the Fat Phobia Scale, the Restricted Activities Scale, the Beck Depression Inventory-Short Form, and the Self-Esteem Scale, before and after treatment, indicate improvement on all four instruments. The therapy approach, which focused on (a) increasing clients' daily activities, (b) examining individual eating patterns, (c) redefining standards of beauty, and (d) teaching assertiveness skills to confront the prejudice and discrimination faced by fat people, is presented in detail. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Automated immunomagnetic processing and separation of Legionella pneumophila with manual detection by sandwich ELISA and PCR amplification of the ompS gene

The culture-independent and automated detection of bacteria in the environment is a scientific and technological challenge. For detection alone, a number of sensitive methods are known (e.g., PCR, enzyme-linked immunosorbent assay [ELISA], fluorescent in situ hybridization) but a major problem remaining is the enrichment and separation of the bacteria that usually occur at low concentrations. Here, we present an automated capturing and separation system, which can easily be combined with one of the sensitive detection techniques. We have developed a method for enrichment and detection of Legionella pneumophila in liquid media. Concentrated microorganisms were either detected by PCR or by sandwich ELISA. The limit of detection with the immunological assay was about 750 bacteria. Using PCR, the equivalent of about 2000 genomes could be detected. The assays were then transferred to a laboratory prototype for automated processing. It was possible to automatically enrich L. pneumophila by immunomagnetic separation (IMS), and again, the bacteria were detected by sandwich ELISA and PCR amplification of the ompS gene. As a novel aspect, ompS gene was used for the first time as a target for the detection of L. pneumophila on magnetic beads. The aim of this work was to develop an automated procedure and a device for IMS of bacteria. With Legionella as a model organism, we could show that such a novel fully automated system can be an alternative to time-consuming conventional cultivation methods for detecting bacteria or other microorganisms.     

Learning knowledge bases of multi-objective evolutionary fuzzy systems by simultaneously optimizing accuracy, complexity and partition integrity

In the last few years, several papers have exploited multi-objective evolutionary algorithms (MOEAs) to generate Mamdani fuzzy rule-based systems (MFRBSs) with different trade-offs between interpretability and accuracy. In this framework, a common approach is to distinguish between interpretability of the rule base (RB), also known as complexity, and interpretability of fuzzy partitions, also known as integrity of the database (DB). Typically, complexity has been used as one of the objectives of the MOEAs, while partition integrity has been ensured by enforcing constraints on the membership function (MF) parameters. In this paper, we propose to adopt partition integrity as an objective of the evolutionary process. To this aim, we first discuss how partition integrity can be measured by using a purposely defined index based on the similarity between the partitions learned during the evolutionary process and the initial interpretable partitions defined by an expert. Then, we introduce a three-objective evolutionary algorithm which generates a set of MFRBSs with different trade-offs between complexity, accuracy and partition integrity by concurrently learning the RB and the MF parameters of the linguistic variables. Accuracy is assessed in terms of mean squared error between the actual and the predicted values, complexity is calculated as the total number of conditions in the antecedents of the rules and integrity is measured by using the purposely defined index. The proposed approach has been experimented on six real-world regression problems. The results have been compared with those obtained by applying the same MOEA, but with only accuracy and complexity as objectives, both to learn only RBs, and to concurrently learn RBs and MF parameters, with and without constraints on the parameter tuning. We show that our approach achieves the best trade-offs between interpretability and accuracy. Finally, we compare our approach with a similar MOEA recently proposed in the literature.     

On reducing computational overhead in multi-objective genetic Takagi–Sugeno fuzzy systems

The use of multi-objective evolutionary algorithms (MOEAs) to generate a set of fuzzy rule-based systems (FRBSs) with different trade-offs between complexity and accuracy has gained more and more interest in the scientific community. The evolutionary process requires, however, a large number of FRBS generations and evaluations. When we deal with high dimensional datasets, these tasks can be very time-consuming, especially when we generate Takagi–Sugeno FRBSs, thus making a satisfactory exploration of the search space very awkward. In this paper, we first analyze the time complexity for both the generation and the evaluation of Takagi–Sugeno FRBSs. Then we introduce a simple but effective technique for speeding up the identification of the rule consequent parameters, one of the most time-consuming phases in Takagi–Sugeno FRBS generation. Finally, we highlight how the application of this technique produces as a side-effect a decoupling of the rules. This decoupling allows us to avoid re-computing consequent parameters of rules which are not directly modified during the evolutionary process, thus saving a considerable amount of time.In the experimental part we first test the correctness of the predicted asymptotical time complexity. Then we show the benefits in terms of computing time saving and improved search space exploration through an example of multi-objective genetic learning of Takagi–Sugeno FRBSs in the regression domain.     

Multi-objective genetic fuzzy classifiers for imbalanced and cost-sensitive datasets

We exploit an evolutionary three-objective optimization algorithm to produce a Pareto front approximation composed of fuzzy rule-based classifiers (FRBCs) with different trade-offs between accuracy (expressed in terms of sensitivity and specificity) and complexity (computed as sum of the conditions in the antecedents of the classifier rules). Then, we use the ROC convex hull method to select the potentially optimal classifiers in the projection of the Pareto front approximation onto the ROC plane. Our method was tested on 13 highly imbalanced datasets and compared with 2 two-objective evolutionary approaches and one heuristic approach to FRBC generation, and with three well-known classifiers. We show by the Wilcoxon signed-rank test that our three-objective optimization approach outperforms all the other techniques, except for one classifier, in terms of the area under the ROC convex hull, an accuracy measure used to globally compare different classification approaches. Further, all the FRBCs in the ROC convex hull are characterized by a low value of complexity. Finally, we discuss how, the misclassification costs and the class distributions are fixed, we can select the most suitable classifier for the specific application. We show that the FRBC selected from the convex hull produced by our three-objective optimization approach achieves the lowest classification cost among the techniques used as comparison in two specific medical applications.     

A Model Study of Ti(OBu)4 Catalyzed Reactions during Reactive Blending of Polyethylene (PE) and Poly(ethylene terephthalate) (PET)

Summary: The effect of metal catalysts in promoting the formation of the comb copolymer between a very low density polyethylene (VLDPE) grafted with diethyl maleate and PET has been studied in this paper following a model study based on low molecular weight molecules resembling the local structure of the reactive groups in the reference macromolecules. Ti(OBu)₄ was used as the catalyst and the reactions were carried out under the same conditions as in the case of the macromolecules species. The model mixtures have been analyzed by FT‐IR, ¹H and ¹³C NMR spectroscopy, thermogravimetric analysis (TGA) and GC‐MS and evidence of the degradation of ester bonds, deactivation of hydroxyl terminals of PET and the possible crosslinking of functionalized polyolefin have been observed. The molecular model process agrees with results obtained for the macromolecular system blending PET and VLDPE grafted with diethyl maleate in a Brabender mixer in the presence of Ti(OBu)₄, as evaluated by mixer torque values and selective extraction results. Therefore, the present model study allows us to both obtain information about reaction mechanism in the complex melt biphasic system and to suggest new strategies to optimize the process.

Brabender torque/time graphics of PET in presence of different amounts of Ti(OBu)₄.     

Enhancing the bactericidal effect of electrolyzed water on Listeria monocytogenes biofilms formed on stainless steel

Biofilms are potential sources of contamination to food in processing plants, because they frequently survive sanitizer treatments during cleaning. The objective of this research was to investigate the combined use of alkaline and acidic electrolyzed (EO) water in the inactivation of Listeria monocytogenes biofilms on stainless steel surfaces. Biofilms were grown on rectangular stainless steel (type 304, no. 4 finish) coupons (2 by 5 cm) in a 1:10 dilution of tryptic soy broth that contained a five-strain mixture of L. monocytogenes for 48 h at 25 degrees C. The coupons with biofilms were then treated with acidic EO water or alkaline EO water or with alkaline EO water followed by acidic EO water produced at 14 and 20 A for 30, 60, and 120 s. Alkaline EO water alone did not produce significant reductions in L. monocytogenes biofilms when compared with the control. Treatment with acidic EO water only for 30 to 120 s, on the other hand, reduced the viable bacterial populations in the biofilms by 4.3 to 5.2 log CFU per coupon, whereas the combined treatment of alkaline EO water followed by acidic EO water produced an additional 0.3- to 1.2-log CFU per coupon reduction. The population of L. monocytogenes reduced by treatments with acidic EO water increased significantly with increasing time of exposure. However, no significant differences occurred between treatments with EO water produced at 14 and 20 A. Results suggest that alkaline and acidic EO water can be used together to achieve a better inactivation of biofilms than when applied individually.     

Cellulase EGZ of Erwinia chrysanthemi: structural organization and importance of His98 and Glu133 residues for catalysis

Biochemical, genetic and primary sequence analyses of the Erwiniachrysanthemi endoglucanase EGZ allowed us to identify two functionaldomains and to locate their boundaries. The catalytic domainextends from residue 1 to 288, while a domain required for EGZto bind to microcrystalline cellulose lies from residues 324to 385. Each domain was found capable of functioning in theabsence of the other. A region rich in Pro, Thr and Ser residueslinks both domains and appeared to be susceptible to proteolyticattack. Based upon predictions derived from a method developedto compare sequences sharing a low level of similarity, e.g.hydrophobic cluster analysis (HCA), we analysed the importanceof either residue His98 or Glul33 in EGZ catalytic activity.Two EGZ-derived proteins were engineered in which either His98or Glul33 amino acid was converted to an Ala residue. Characterizationof the purified proteins showed that no enzymatic activity couldbe detected, by using carboxymethylcellulose (CMC) or paranitrophenyl-cellobioside(pNPC) as substrates, while both mutated proteins retained thecapacity to bind to microcrystalline cellulose. These studies,which to date constitute the first experimental testing of HCA-derivedpredictions, allowed us to identify two particular amino acidsinvolved in cellulolytic activity. By taking into account datafrom chemical modification studies of other cellulases, we speculatethat the His98 residue is involved in the folding of the catalyticdomain while the Glul33 residue intervenes directly in the ß,1–4 glycosidic bond cleavage.