Inkjet printing and adhesion characterisation of conductive tracks on a commercial printed circuit board material

Silver nanoparticle-based conductive tracks were inkjet printed using a piezoelectric drop-on-demand inkjet printer on a commercially available electronics grade fibre glass (E-glass) reinforced substrate material, and the experimental results have been summarised. Ink jetting was done on two variants of this substrate material, viz. etched and unetched, to determine the influence of substrate surface topography on adhesion and accuracy of the printed tracks. The pull-off adhesion test method was used to quantify adhesive strength. The dependence of the pull-off test results on local geometry of the test area are illustrated with the aid of scanning electron microscope images and interferometer studies. Based on the outcomes of the experiments, conclusions concerning the suitable surface topography for inkjet printing have been arrived at.     

Metabolic Remodeling with Hepatosteatosis Induced Vascular Oxidative Stress in Hepatic ERK2 Deficiency Mice with High Fat Diets

We previously demonstrated the marked hepatosteatosis and endothelial dysfunction in hepatocyte-specific ERK2 knockout mice (LE2KO) with a high-fat/high-sucrose diet (HFHSD), but detailed metabolic changes and the characteristics in insulin-sensitive organs were not tested. This study aimed to characterize metabolic remodeling with changes in insulin-sensitive organs, which could induce endothelial dysfunction in HFHSD-LE2KO. The serum glucose and fatty acid (FA) were modestly higher in HFHSD-LE2KO than HFHSD-Control. FA synthesis genes were up-regulated, which was associated with the decreased phosphorylation of AMPK and ACC, and with the up-regulation of SREBP-1 in the liver from HFHSD-LE2KO. In FA and amino acids fraction analysis, arachidonic acid/eicosapentaenoic acid ratio, L-ornithine/arginine ratio, asymmetric dimethylarginine and homocysteine levels were elevated in HFHSD-LE2KO. Insulin-induced phosphorylation of AKT was blunted in skeletal muscle. Serum leptin and IL-1β were elevated, and serum adiponectin was decreased with the enlargement of epididymal adipocytes. Finally, the enhanced superoxide levels in the aorta, which were blunted with CCCP, apocynin, and tempol, were observed in HFHSD-LE2KO. A pre-incubation of aortic rings with tempol improved endothelial dysfunction in HFHSD-LE2KO. HFHSD-LE2KO revealed an acceleration of FA synthesis in the liver leading to insulin resistance in skeletal muscle and the enlargement of visceral adipocytes. Global metabolic remodeling such as changes in arginine metabolism, ω3/ω6 ratio, and adipocytokines, could affect the vascular oxidative stress and endothelial dysfunction in HFHSD-LE2KO.     

4D printing shape memory polymers for dynamic jewellery and fashionwear

4D printing is a novel approach that enables dynamic functionality in ordinary static object. We used a methacrylated semicrystalline polymer to print objects exhibiting thermally triggered shape memory behaviour. By exploring various molecular weights, it was found that a methacrylated polycaprolactone polymer with a number average molecular weight of 10,000?g?mol^?1 exhibited the best thermal and mechanical behaviour. The effect of dyes’ addition to the ink formulation on the photopolymerisation and on the printing processes was evaluated. The ink was utilised for demonstrating fabrication of dynamic jewellery and a shoe accessory by Digital Light Processing printing.     

Mean shift trackers with cross-bin metrics

Cross-bin metrics have been shown to be more suitable than bin-by-bin metrics for measuring the distance between histograms in various applications. In particular, a visual tracker that minimizes the earth mover's distance (EMD) between the candidate and reference feature histograms has recently been proposed. This tracker was shown to be more robust than the Mean Shift tracker, which employs a bin-by-bin metric. In each frame, the former tracker iteratively shifts the candidate location by one pixel in the direction opposite to the EMD's gradient until no improvement is made. This optimization process involves the clustering of the candidate feature density in feature space, as well as the computation of the EMD between the candidate and reference feature histograms after each shift of the candidate location. In this paper, alternative trackers that employ cross-bin metrics as well, but that are based on Mean Shift (MS) iterations, are derived. The proposed trackers are simpler and faster due to 1) the use of MS-based optimization, which is not restricted to single pixel shifts, 2) abstention from any clustering of feature densities, and 3) abstention from EMD computations in multidimensional spaces.     

Studies on peroxidized lipids. V. Formation and characterization of 1,4-dihydropyridine-3,5-dicarbaldehydes as model of fluorescent components in lipofuscin

We investigated fluorescence properties of 1,4-dihydropyridine-3,5-dicarbaldehydes and their formation in mild reaction of primary amines and malonaldehyde, in order to clarify the role of malonaldehyde in the formation of fluorescent components of lipofuscin. The compounds exhibited fluorescence with excitation maxima at 375–405 nm and emission maxima at 435–465 nm, which was similar to those of lipofuscin and the fluorescent substances derived from the reaction of oxidized fatty acids with primary amines. Fluorescence of the compounds was greatly affected in acidic medium and little influenced in alkaline medium or by the metal chelator. The compounds lost fluorescence by treatment with sodium borohydride. They were inert to thiobarbituric acid reaction. Some of the fluorescence properties of the compounds were different from those of lipofuscin and the related fluorescent substances. Mild reaction of methylamine with pure malonaldehyde gave a single fluorescent compound, 1,4-dimethyl-1,4-dihydropyridine-3,5-dicarbaldehyde (Ia), and the reaction with the acid hydrolysate of tetramethoxypropane gave Ia and 1-methyl-4-(dimethoxyethyl)-1,4-dihydropyridine-3,5-dicarbaldehyde (IIa), the latter being produced from the impurity in the hydrolysate. These reactions produced a non-fluorescent Schiff base, a 1∶1-adduct of methylamine and malonaldehyde (IIIa), as a major product. It looks unlikely that malonaldehyde is the only product of lipid oxidation that produces fluorescent components in lipofuscin complex.     

Essential Amino Acid Composition of Fleshy Fruits Versus Maintenance Requirements of Passerine Birds

Nutritional analyses were performed on 27 fruit species that are eaten by frugivorous birds in east Mediterranean habitats in Israel. The essential amino acid (EAA) profile [compared by principal component analysis (PCA)] of these fruits indicated two distinct groups of fruits. The main group consisted of 23 species that were similar in their relatively low total EAA quantities and unbalanced EAA profiles. On average, the EAAs phenylalanine and tyrosine were most concentrated and histidine least (tryptophan was not measured). Comparing the relative amounts of EAAs in fruits with required amounts for maintenance of granivorous passerine birds revealed that these fruits are deficient in all or most EAAs. The sulfur-containing amino acids (methionine and cystine) were most limiting relative to the required amount (41–61% below requirement), while four others (arginine, lysine, isoleucine, and leucine) were severely deficient (30–37% below requirement). These results complement reports suggesting that frugivorous birds have lower total protein demands than granivores. The second group of four fruit species had relatively high total EAA contents. Each of these fruits appeared to contain especially large quantities of some EAAs, but it was uncertain whether some high concentrations could have resulted from interactions in the pulp during preparation and chemical analysis.     

Random low-degree polynomials are hard to approximate

We study the problem of how well a typical multivariate polynomial can be approximated by lower-degree polynomials over mathbb F{mathbb F} . We prove that almost all degree d polynomials have only an exponentially small correlation with all polynomials of degree at most d − 1, for all degrees d up to Θ(n). That is, a random degree d polynomial does not admit a good approximation of lower degree. In order to prove this, we prove far tail estimates on the distribution of the bias of a random low-degree polynomial. Recently, several results regarding the weight distribution of Reed–Muller codes were obtained. Our results can be interpreted as a new large deviation bound on the weight distribution of Reed–Muller codes.     

Flame acceleration in channels with obstacles in the deflagration-to-detonation transition

It was demonstrated recently in Bychkov et al. [Bychkov et al., Phys. Rev. Lett. 101 (2008) 164501], that the physical mechanism of flame acceleration in channels with obstacles is qualitatively different from the classical Shelkin mechanism. The new mechanism is much stronger, and is independent of the Reynolds number. The present study provides details of the theory and numerical modeling of the flame acceleration. It is shown theoretically and computationally that flame acceleration progresses noticeably faster in the axisymmetric cylindrical geometry as compared to the planar one, and that the acceleration rate reduces with increasing Mach number and thereby the gas compressibility. Furthermore, the velocity of the accelerating flame saturates to a constant value that is supersonic with respect to the wall. The saturation state can be correlated to the Chapman-Jouguet deflagration as well as the fast flames observed in experiments. The possibility of transition from deflagration-to-detonation in the obstructed channels is demonstrated.     

Full penetration welding of thick high tensile strength steel plate with high-power disk laser in low vacuum

This study was undertaken in order to investigate the effect of reduced ambient pressure from an atmospheric pressure (101 kPa) to 0.1 kPa on one-pass full penetration welding of thick high-tensile strength steel plate of 23 mm thickness. A 16 kW disk laser of 1030 nm in wavelength was employed to weld HT980 grade plates at the speed of 5–25 mm/s. In partial penetration welding, it was revealed that humping phenomena occurred easily. Full penetration welding of the high-tensile strength steel plates could not be achieved at 101 kPa. On the other hand, full penetration welding was obtained at the welding speed of less than 20 mm/s at the pressure of less than 10 kPa. Especially, at 0.1 kPa, and 17 and 20 mm/s, sound weld joints without defects were obtained. According to the observation results of a keyhole inlet and a surface molten pool during welding with a high-speed video camera, the melt in front of a keyhole was smaller and the behaviour of a keyhole and a plume was much more stable at 0.1 kPa than at 101 kPa. Moreover, in the full penetration welding, spattering was suppressed under the proper conditions. Such phenomena became more stable in fast welding. It was revealed in laser welding of thick high-tensile strength steel plates that the formation of narrow I-shaped weld beads by achieving full-penetration welding in low vacuum was essential for the production of sound welds without defect.