Chemical sensing materials characterization by Kelvin probe technique

This paper deals first of all with an improvement of the Kelvin probe (KP) theory taking into consideration the series resistance of the input circuit. Then it illustrates a number of work function measurements performed on self-assembled monolayers interacting with varieties of analytes, and on Langmuir–Blodgett (LB) films of porphyrins of different thickness. The output intensities of the work function have been investigated and comments are given of the results obtained. The link between the work function and thickness of material under test has been analyzed and discussed as a method for the coverage factor estimation of absorbing surfaces.     

Effect of the electronic properties of Mo sulfide phase on the hydrotreating activity of catalysts supported on Al2O3, Nb2O5 and Nb2O5/Al2O3

Activity in thiophene hydrodesulfurization (HDS) and in the three routes of 2,6-dimethylaniline (DMA) decomposition was examined on Mo sulfide catalysts supported on Al₂O₃, Nb₂O₅ and Nb₂O₅–Al₂O₃. Catalysts activity is enhanced when Mo phase is deposited on niobium-containing support. For HDS and for the hydrogenation route of DMA decomposition, the niobium-containing support strongly contributes to the catalyst activity whereas the activity of the Mo phase per Mo atom decreases with the increase of niobium amount in the support. By contrast, as for the DMA route, which leads to xylene formation (XYL), the activity of the Mo sulfide phase per Mo atom is strongly enhanced. The electronic properties of the MoS₂ phase were studied by means of IR spectroscopy of CO adsorption. Comparison of ν(CO/Mo) wavenumbers reveals an upward shift when Mo sulfide phase is deposited on Nb-containing support. The modification of the electronic properties of the sulfide phase is related to an interaction Mo–Nb either through the formation of a mixed Mo–Nb sulfide phase, or through the interaction MoS₂ slabs – support whose strength depends on the support acidity. Hence, the beneficial effect for xylene formation route is attributed to a decrease of the electron density of the Mo sulfide phase that should strengthen the DMA adsorption on the sulfide phase.     

The relation of family functioning to violence among inner-city minority youths.

The relationship between family influences and participation in violent and nonviolent delinquent behavior was examined among a sample of 362 African American and Latino male adolescents living in the inner city. Participants were classified into three groups: (a) nonoffenders, (b) nonviolent offenders, and (c) violent offenders. Families in the violent delinquent group reported poorer discipline, less cohesion, and less involvement than the other two groups. These results were consistent across ethnic groups. However, the factor Beliefs About Family related to violence risk in opposite directions for African American and Latino families. These results highlight the need to look at ethnic group differences when constructing models of risk. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Paradox Effect of Calcification in Carotid Atherosclerosis: Microcalcification Is Correlated with Plaque Instability

Background: this study aims to investigate the possible association among the histopathologic features of carotid plaque instability, the presence of micro- or macrocalcifications, the expression of in situ inflammatory biomarkers, and the occurrence of the major risk factors in this process in a large series of carotid plaques. Methods: a total of 687 carotid plaques from symptomatic and asymptomatic patients were collected. Histological evaluation was performed to classify the calcium deposits in micro or macrocalcifications according to their morphological features (location and size). Immunohistochemistry was performed to study the expression of the main inflammatory biomarkers. Results: results here reported demonstrated that calcifications are very frequent in carotid plaques, with a significant difference between the presence of micro- and macrocalcifications. Specifically, microcalcifications were significantly associated to high inflamed unstable plaques. Paradoxically, macrocalcifications seem to stabilize the plaque and are associated to a M2 macrophage polarization instead. Discussion: the characterization of mechanisms involved in the formation of carotid calcifications can lay the foundation for developing new strategies for the management of patients affected by carotid atherosclerosis. Data of this study could provide key elements for an exhaustive evaluation of carotid plaque calcifications allowing to establish the risk of associated clinical events.     

Reduction of cyanide content of cassava flour in Mozambique by the wetting method

Fifty cassava flour samples from Mogincual District of Nampula Province in Mozambique were found to contain, on average, 43 mg HCN equivalents/kg flour (ppm), of total cyanide, which is typical for a year of average rainfall. Five gram samples of the 30 flour samples of highest cyanide content were mixed with water and left for 5 h at 30 °C and it was found that the mean% retention of cyanide was 16.7%. Using 500 g instead of 5 g samples caused an increase in the % retention due to accumulation of the very weak acid, HCN, in the damp flour mass, which also decreased its pH and somewhat reduced the rate of breakdown of linamarin catalysed by linamarase. This problem was overcome by spreading out the damp flour in an approximately 0.5 cm thick layer on a tray, which allowed the release of HCN.     

Matching island topologies to problem structure in parallel evolutionary algorithms

In the context of Parallel Evolutionary Algorithms, it has been shown that different population structures induce different search performances. Nevertheless, no work has shown a clear cut evidence that there is a correlation between the solver’s population structure and the problem’s network structure. In this work, we verify this correlation performing a clear and systematic analysis of a large set of population structures (based on the well known β-graphs and NK-landscape problems. Furthermore, we go beyond our findings in these idealised experiments by analysing the performance of variable-topology EAs on a dynamic real-world problem, the Multi-Skills Call Centre.     

Assessing allergenicity of different tomato ecotypes by using pooled sera of allergic subjects: identification of the main allergens

An evaluation of the potential allergenicity of different tomato ecotypes is reported. Twelve tomato ecotypes were assessed through a proteomic approach, using pools of sera of allergic patients from two different regions (Emilia Romagna in Northern Italy and Campania in Southern Italy), in order to identify the major allergens and evaluate differences in IgE binding properties of the tomato cultivars. Pooled sera of allergic people from Emilia Romagna showed as the main allergen a suberization-associated anionic peroxidase, whereas pooled sera of allergic patients from Campania were mostly reactive to profilin. The two proteins were identified through a proteomic approach based on the use of high-resolution mass spectrometric techniques. Quite interestingly, in some cases, several ecotypes showed a less reactivity toward patients?? sera than other, potentially indicating the possibility to identify ipoallergenic varieties. Anyway, the allergenic pattern response to tomatoes was serum-specific, indicating that the allergenic properties of different tomato ecotypes are defined by the specific proteins to which the patient is sensitized, a strong indication that ipoallergenicity of the different ecotypes is possible, but mostly related to the individual susceptibility.     

Impact of trehalose,sucrose and/or maltodextrin addition on aroma retention in freeze dried strawberry puree

Trehalose was studied as a drying aid to establish its impact on aroma retention in freeze dried strawberry puree. The evaluation was done by sensory analysis and headspace‐solid phase microextraction‐gas chromatography with a mass detector (HS‐SPME‐GC‐MS); results were compared with those obtained using sucrose and maltodextrin (MD) as drying aids. The carbohydrate used significantly modified the type and concentration of volatiles retained during freeze drying. HS‐SPME‐GC‐MS outcomes showed that the use of trehalose (alone or with MD) resulted in the product with the chromatographic profile most similar to fresh strawberry puree, being different from sucrose and MD. Meanwhile, sensory analysis showed a similarity with the aromatic profiles when using trehalose or sucrose, remaining both different from MD. This study proved that the use of trehalose as a drying aid can be beneficial on volatile aroma retention and that different combinations of organic volatiles can lead to similar sensory profiles.     

Accumulation of non-proteolytic aminoacyl derivatives in Parmigiano-Reggiano cheese during ripening

For the first time, the identification of N-γ-glutamyl-, N-pyroglutamyl- and N-lactoyl-amino acids in Parmigiano-Reggiano cheese is reported. Their structures were assigned by electrospray mass spectrometric analysis and demonstrated for several compounds by the synthesis of authentic specimens and sample spiking. The comparison with the synthesised compounds also allowed the determination of their absolute stereochemistry (l,l), which indicated a common enzymatic origin. All these molecules were shown to accumulate in Parmigiano-Reggiano during ripening, probably because of a resistance to proteolysis due to their unusual structures. Thus, these compounds can be used as markers of ripening time and may be involved in the development of the pleasant flavour of aged cheeses. Their presence in other cheeses was also demonstrated.