Calibration of a sheet of thermosensitive liquid crystals viewed non-orthogonally

A thin adhesive sheet of encapsulated thermochromic liquid crystals (TLCs) is attached to a submerged plate, impinged by an ionic jet in an electrohydrodynamics experiment. In order to measure the local temperature and obtain the heat transfer coefficients on the plate, a proper calibration of the liquid crystals is needed. A colour can be expressed as a weighted combination of three attributes: hue, saturation and intensity. In TLCs, hue is a function of temperature in a narrow range. However, TLCs colour also depends on the angle under which a point on the sheet is viewed, as well as on the lighting conditions. Due to the particular specifications and inherent constraints of our experimental apparatus, the calibration procedure becomes fairly complicated. In fact, the digital camera for the acquisition of the colour pattern has to be positioned on the side of the sheet. Besides, the TLCs are non-uniformly lighted, including the presence of shadows. The relationship between the hue field and the temperature field on the plate is then obtained by means of a filtering and interpolation technique, as described in the paper. The overall accuracy of the developed technique is ±0.1 K.     

Traditional and innovative protective coatings for outdoor bronze: Application and performance comparison

A comparative evaluation of traditional and innovative coatings for outdoor bronze surfaces was carried out, including blending or pre‐treatment with non‐toxic corrosion inhibitors on bare and patinated bronze surfaces to simulate both as cast and aged surfaces. Coatings recently applied in bronze conservation practice, commercially available coatings and an innovative end‐capped poly(lactic acid) with a benzotriazole (BTA) moiety have been tested, as well as a triple‐layer system (wax/acrylic polymer/wax). BTA, single‐layer Soter wax, and double layer Incral44/Soter wax were used as a reference. The products were evaluated in terms of aesthetic features, molecular structure, and corrosion protection by means of colorimetric, spectroscopic, and electrochemical tests. All inhibitors showed similar or significantly better results compared to BTA. In particular, sodium oleate and tolyltriazole could be considered as promising lower‐toxicity alternatives to BTA, while the triple‐layer coating applied without pre‐filming inhibitors proved to give a very high protection against corrosion. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46011.     

Evaluation of a grid based molecular dynamics approach for polypeptide simulations

Molecular dynamics is very important for biomedical research because it makes possible simulation of the behavior of a biological macromolecule in silico. However, molecular dynamics is computationally rather expensive: the simulation of some nanoseconds of dynamics for a large macromolecule such as a protein takes very long time, due to the high number of operations that are needed for solving the Newton's equations in the case of a system of thousands of atoms. In order to obtain biologically significant data, it is desirable to use high-performance computation resources to perform these simulations. Recently, a distributed computing approach based on replacing a single long simulation with many independent short trajectories has been introduced, which in many cases provides valuable results. This study concerns the development of an infrastructure to run molecular dynamics simulations on a grid platform in a distributed way. The implemented software allows the parallel submission of different simulations that are singularly short but together bring important biological information. Moreover, each simulation is divided into a chain of jobs to avoid data loss in case of system failure and to contain the dimension of each data transfer from the grid. The results confirm that the distributed approach on grid computing is particularly suitable for molecular dynamics simulations thanks to the elevated scalability.     

Comparison of the Diatheva STEC FLUO with BAX System Kits for Detection of O157:H7 and Non-O157 Shiga Toxin-Producing <Emphasis Type="Italic">Escherichia coli</Emphasis> (STEC) in Ground Beef and Bean Sprout Samples Using Different Enrichment Protocols

The aim of this study was to assess the performance of the Diatheva STEC FLUO and BAX System real-time PCR assays for detection of Shiga toxin-producing Escherichia coli (STEC) (stx1/stx2 and eae target genes) and O-group identification in ground beef and bean sprout samples. Ground beef (325 g or 25 g) and mung bean sprout (25 g) samples were inoculated with ~?10 CFU of the “top five” STEC (O157:H7, O26, O103, O111, and O145 as specified in EU regulation ISO13136:2012), enriched using different broths and incubation temperatures, and tested using the Diatheva and BAX real-time PCR assays. In ground beef, both molecular methods were able to detect the “top five” STEC, and lower Ct values were observed for the Diatheva kits compared to BAX System. The O111-contaminated samples gave negative results with both methods using mTSB?+?novobiocin for enrichment. In bean sprouts, both methods provided positive results, although detection was not possible using mTSB?+?acriflavin/cefsulodin/vancomycin for enrichment. In conclusion, the Diatheva and BAX methods detected the “top five” STEC in ground beef and bean sprouts when inoculated at low levels. Both assays provided equivalent results in terms of performance and reliability. Thus, the Diatheva kits are comparable to reference STEC-detection methods and could be used by the food industry to reliably detect the “top five” STEC.     

Scaling of the energy gap in pattern-hydrogenated graphene

Recent experiments show that a substantial energy gap in graphene can be induced via patterned hydrogenation on an iridium substrate. Here, we show that the energy gap is roughly proportional to N(H)(1/2)/N(C) when disorder is accounted for, where N(H) and N(C) denote concentrations of hydrogen and carbon atoms, respectively. The dispersion relation, obtained through calculation of the momentum-energy resolved density of states, is shown to agree with previous angle-resolved photoemission spectroscopy results. Simulations of electronic transport in finite size samples also reveal a similar transport gap, up to 1 eV within experimentally achievable N(H)(1/2)/N(C) values.     

Controlled continuous patterning of polymeric nanofibers on three-dimensional substrates using low-voltage near-field electrospinning

We report on a continuous method for controlled electrospinning of polymeric nanofibers on two-dimensional (2D) and three dimensional (3D) substrates using low voltage near-field electrospinning (LV NFES). The method overcomes some of the drawbacks in more conventional near-field electrospinning by using a superelastic polymer ink formulation. The viscoelastic nature of our polymer ink enables continuous electrospinning at a very low voltage of 200 V, almost an order of magnitude lower than conventional NFES, thereby reducing bending instabilities and increasing control of the resulting polymer jet. In one application, polymeric nanofibers are freely suspended between microstructures of 3D carbon on Si substrates to illustrate wiring together 3D components in any desired pattern.     

Piezoelectric potential in vertically aligned nanowires for high output nanogenerators

In this work we analyze the coupled piezoelectric and semiconductive behavior of vertically aligned ZnO nanowires under uniform compression. The screening effect on the piezoelectric field caused by the free carriers in vertically compressed zinc oxide nanowires (NWs) has been computed by means of both analytical considerations and finite element calculations. We predict that, for typical geometries and donor concentrations, the length of the NW does not significantly influence the maximum output piezopotential because the potential mainly drops across the tip, so that relatively short NWs can be sufficient for high-efficiency nanogenerators, which is an important result for wet-chemistry fabrication of low-cost, CMOS- or MEMS-compatible nanogenerators. Furthermore, simulations reveal that the dielectric surrounding the NW influences the output piezopotential, especially for low donor concentrations. Other parameters such as the applied force, the sectional area and the donor concentration have been varied in order to understand their effects on the output voltage of the nanogenerator.     

Molecular Ordering at the Interface Between Liquid Water and Rutile TiO2(110)

The pivotal importance of TiO₂ as a technological material involves most applications in an aqueous environment, but the single‐crystal TiO₂/bulk‐water interfaces are almost completely unexplored, since up to date solid/liquid interfaces are more difficult to access than surfaces in ultrahigh vacuum (UHV). Only a few techniques (as scanning probe microscopy) offer the opportunity to explore these systems under realistic conditions. The rutile TiO₂(110) surface immersed in high‐purity water is studied by in situ scanning tunneling microscopy. The large‐scale surface morphology as obtained after preparation under UHV conditions remains unchanged upon prolonged exposure to bulk water. Moreover, in contrast to UHV, atomically resolved images show a twofold periodicity along the [001] direction, indicative of an ordered structure resulting from the hydration layer. This is consistent with density‐functional theory based molecular dynamics simulations where neighboring interfacial molecules of the first water layer in contact with the bulk liquid form dimers. By contrast, this dimerization is not observed for a single adsorbed water monolayer, i.e., in the absence of bulk water.     

Comparative study by computed radiography,histology, and scanning electron microscopy of the articular cartilage of normal goats and in chronic infection with caprine arthritis‐encephalitis virus

In the northeast of Brazil, caprine arthritis‐encephalitis (CAE) is one of the key reasons for herd productivity decreasing that result in considerable economic losses. A comparative study was carried out using computed radiography (CR), histological analysis (HA), and scanning electronic microscopy (SEM) of the joints of CAE infected and normal goats. Humerus head surface of positive animals presented reduced joint space, increased bone density, and signs of degenerative joint disease (DJD). The carpal joint presented no morphological alterations in CR in any of the animals studied. Tarsus joint was the most affected, characterized by severe DJD, absence of joint space, increased periarticular soft tissue density, edema, and bone sclerosis. Histological analysis showed chronic tissue lesions, complete loss of the surface zone, absence of proteoglycans in the transition and radial zones and destruction of the cartilage surface in the CAE positive animals. Analysis by SEM showed ulcerated lesions with irregular and folded patterns on the joint surface that distinguished the limits between areas of normal and affected cartilage. The morphological study of the joints of normal and CAE positive goats deepened understanding of the alteration in the tissue bioarchitecture of the most affected joints. The SEM finding sustained previous histological reports, similar to those found for rheumatoid arthritis, suggesting that the goat infected with CAE can be considered as a potential model for research in this area. Microsc. Res. Tech. 77:11–16, 2014. © 2013 Wiley Periodicals, Inc.     

Excretion of Avenanthramides,Phenolic Acids and their Major Metabolites Following Intake of Oat Bran

1 Scope

Wholegrain has been associated with reduced chronic disease mortality, with oat intake particularly notable for lowering blood cholesterol and glycemia. To better understand the complex nutrient profile of oats, we studied urinary excretion of phenolic acids and avenanthramides after ingestion of oat bran in humans.

2 Methods and results

After a 2‐d (poly)phenol‐low diet, seven healthy men provided urine 12 h before and 48 h after consuming 60 g oat bran (7.8 μmol avenanthramides, 139.2 μmol phenolic acids) or a phenolic‐low (traces of phenolics) control in a crossover design. Analysis by ultra‐high performance liquid chromatography (UPLC)–MS/MS showed that oat bran intake resulted in an elevation in urinary excretion of 30 phenolics relative to the control, suggesting that they are oat bran‐derived. Mean excretion levels were elevated between 0–2 and 4–8 h, following oat bran intake, and amounted to a total of 33.7 ± 7.3 μmol total excretion (mean recovery: 22.9 ± 5.0%), relative to control. The predominant metabolites included: vanillic acid, 4‐ and 3‐hydroxyhippuric acids, and sulfate‐conjugates of benzoic and ferulic acids, which accounted collectively for two thirds of total excretion.

3 Conclusion

Oat bran phenolics follow a relatively rapid urinary excretion, with 30 metabolites excreted within 8 h of intake. These levels of excretion suggest that bound phenolics are, in part, rapidly released by the microbiota.