Lithography‐Free Fabrication of Silica Nanocylinders with Suspended Gold Nanorings for LSPR‐Based Sensing

Tunable plasmonic platforms are important for a variety of applications such as photovoltaics, LED's, optoelectronics, medical research, and biosensors. In particular, development of label‐free plasmonic biosensors is one of the key research areas that utilizes plasmonic nanostructures for detection of biologically relevant molecules at low concentrations. The authors have developed a cost‐effective, fast, and lithography‐free method to fabricate transparent fused silica nanocylinders. The technique allows tuning of nanocylinder height, diameter, and density and can be scaled to large surface areas, such as 8 in. wafers. The authors demonstrate that gold coated nanocylinders support localized surface plasmon resonances (LSPR) from visible to near infrared wavelengths. The plasmonic platform can be characterized as suspended gold nanorings and exhibits a sensitivity of 658 nm RIU^–1 with a figure‐of‐merit of 10, comparable to other state‐of‐the‐art LSPR sensing platforms that utilize more complex nanofabrication pathways. It was observed that the LSPR peak positions can be controlled by varying the geometry of the nanocylinders. The authors illustrate surface functionalization, biosensing, and surface regeneration properties of the platform using thiols and detection of bovine serum albumin (BSA). The observed LSPR shifts for 11‐mercaptoundecanoic acid and BSA was 12 and 26 nm, respectively.     

Nitrogen Oxides Ozonation as a Method for NOx Emission Abatement

Attempts to develop new technologies of reduction of NO_x emission are still carried out all around the world. However, most of them as literature survey suggests is focused on NO_x emission control from power plants and mobile vehicles. Fewer investigations are conducted on the NO_x emission abatement from the chemical industry. One of the relatively new approaches is the application of ozone injection into exhaust gas stream followed by an absorption process. Ozone is used to transform NO_x to higher nitrogen oxides that are more soluble in water, and therefore the higher yield of nitric acid is expected. The main objective of this article is to present results of our studies in which the effectiveness of the ozonation process, as well as the dependence of the conversion rate and the selectivities of NO ozonation into NO₂, N₂O₅ and HNO₃ on the residence time of reagents in the reactor space were studied. Results of laboratory investigations were confirmed during ozonation experiments with real exhaust gases from a nitric acid pilot plant in Fertilizers Research Institute in Pulawy, Poland.     

Structures of Alcohol Dehydrogenases from Ralstonia and Sphingobium spp. Reveal the Molecular Basis for Their Recognition of ‘Bulky–Bulky’ Ketones

Alcohol dehydrogenases (ADHs) are applied in industrial synthetic chemistry for the production of optically active secondary alcohols. However, the substrate spectrum of many ADHs is narrow, and few, for example, are suitable for the reduction of prochiral ketones in which the carbonyl group is bounded by two bulky and/or hydrophobic groups; so-called ‘bulky–bulky’ ketones. Recently two ADHs, RasADH from Ralstonia sp. DSM 6428, and SyADH from Sphingobium yanoikuyae DSM 6900, have been described, which are distinguished by their ability to accept bulky–bulky ketones as substrates. In order to examine the molecular basis of the recognition of these substrates the structures of the native and NADPH complex of RasADH, and the NADPH complex of SyADH have been determined and refined to resolutions of 1.5, 2.9 and 2.5 Å, respectively. The structures reveal hydrophobic active site tunnels near the surface of the enzymes that are well-suited to the recognition of large hydrophobic substrates, as determined by modelling of the bulky–bulky substrate n-pentyl phenyl ketone. The structures also reveal the bases for NADPH specificity and (S)-stereoselectivity in each of the biocatalysts for n-pentyl phenyl ketone and related substrates.     

Pyrolysed 3D‐Carbon Scaffolds Induce Spontaneous Differentiation of Human Neural Stem Cells and Facilitate Real‐Time Dopamine Detection

Structurally patterned pyrolysed three‐dimensional carbon scaffolds (p3D‐carbon) are fabricated and applied for differentiation of human neural stem cells (hNSCs) developed for cell replacement therapy and sensing of released dopamine. In the absence of differentiation factors (DF) the pyrolysed carbon material induces spontaneous hNSC differentiation into mature dopamine‐producing neurons and the 3D‐topography promotes neurite elongation. In the presence and absence of DF, ≈73–82% of the hNSCs obtain dopaminergic properties on pyrolysed carbon, a to‐date unseen efficiency in both two‐dimensional (2D) and 3D environment. Due to conductive properties and 3D environment, the p3D‐carbon serves as a neurotransmitter trap, enabling electrochemical detection of a significantly larger dopamine fraction released by the hNSC derived neurons than on conventional 2D electrodes. This is the first study of its kind, presenting new conductive 3D scaffolds that provide highly efficient hNSC differentiation to dopaminergic phenotype combined with real‐time in situ confirmation of the fate of the hNSC‐derived neurons.     

Effect of Compression with Oscillatory Torsion Processing on Structure and Properties of Cu

The results presented in this study were concerned with microstructures and mechanical properties of polycrystalline Cu subjected to plastic deformation by a compression with oscillatory torsion process. Different deformation parameters of the compression with oscillatory torsion process were adopted to study their effects on the microstructure and mechanical properties. The deformed microstructure was characterized quantita- tively by electron backscattered diffraction (EBSD) and scanning transmission electron microscopy (STEM). Mechanical properties were determined on an MTS QTest/10 machine equipped with digital image correlation. From the experimental results, processes performed at high compression speed and high torsion frequency are recommended for refining the grain size. The size of structure elements, such as average grain size (D) and subgrain size (d), reached 0.42 μm and 0.30 μm, respectively, and the fraction of high angle boundaries was 35% when the sample was deformed at a torsion frequency f = 1.6 Hz and compression rate v = 0.04 mm/s. These deformation parameters led to an improvement in the strength properties. The material exhibited an ultimate tensile strength (UTS) of 434 MPa and a yield strength (YS) of 418 MPa. These values were about two times greater than those of the initial state.     

Stresses Generated During Convective and Microwave Drying

Abstract

An outline of the mechanistic model of convective and microwave drying of saturated capillary-porous materials is presented. The model was derived in the framework of irreversible thermodynamics. Particular attention is devoted to construction of the term describing the power of microwave radiation absorbed per unit volume, which is converted into internal heat source. The qualitative difference in distribution of temperature, moisture content, and the drying-induced stresses in materials under convective and microwave drying is illustrated in the examples of cylindrical kaolin samples. The diagrams of acoustic emission are taken off on-line from these samples in order to illustrate the development of material destruction caused by the stresses induced during both convective and microwave drying.     

Dried strawberries as a high nutritional value fruit snack

The purpose of this study was to determine the possibility of using a chokeberry juice concentrate as a component of osmotic solution and convection-microwave-vacuum drying applying to obtain dried pro-health-promoting strawberries. The research material was Honeoye strawberries, which were dehydrated in sucrose and sucrose with chokeberry juice concentrate addition, and then subjected to microwave-convection-vacuum or freeze-drying. Analyses were conducted to determine the influence of the applied processes on vitamin C content, total polyphenols, antioxidant activity, and sensory properties in dried fruit. Study results confirmed the possibility of using a chokeberry juice concentrate as a component of the osmotic solution, especially with regard to polyphenolics content and antioxidant activity. In addition, convection-microwave-vacuum drying was shown to be a promising technology for the production of dried strawberries, with high pro-health potential and acceptable sensory qualities.     

Macroalgal Defense against Competitors and Herbivores

Macroalgae are the source of many harmful allelopathic compounds, which are synthesized as a defense strategy against competitors and herbivores. Therefore, it can be predicted that certain species reduce aquaculture performance. Herein, the allelopathic ability of 123 different taxa of green, red, and brown algae have been summarized based on literature reports. Research on macroalgae and their allelopathic effects on other animal organisms was conducted primarily in Australia, Mexico, and the United States. Nevertheless, there are also several scientific reports in this field from South America and Asia; the study areas in the latter continents coincide with areas where aquaculture is highly developed and widely practiced. Therefore, the allelopathic activity of macroalgae on coexisting animals is an issue that is worth careful investigation. In this work, we characterize the distribution of allelopathic macroalgae and compare them with aquaculture locations, describe the methods for the study of macroalgal allelopathy, present the taxonomic position of allelopathic macroalgae and their impact on coexisting aquatic competitors (Cnidaria) and herbivores (Annelida, Echinodermata, Arthropoda, Mollusca, and Chordata), and compile information on allelopathic compounds produced by different macroalgae species. This work gathers the current knowledge on the phenomenon of macroalgal allelopathy and their allelochemicals affecting aquatic animal (competitors and predators) worldwide and it provides future research directions for this topic.     

Influence of the Surface Enhancement on the Flow Boiling Heat Transfer in a Minichannel

This paper presents results concerning flow boiling heat transfer in three parallel vertically oriented and asymmetrically heated rectangular minichannels. Each minichannel was 1.7 mm deep, 16 mm wide, and 180 mm long. The heated element for Fluorinert FC-72 flowing in the minichannels was a thin foil. Infrared thermography was used to determine changes in the temperature on the outer smooth side of the foil. Two-phase flow patterns were observed through a glass pane. The heated surfaces in contact with the fluid in the minichannels differed in roughness. In one minichannel the surface was smooth. In the other two, the surface was enhanced. Two types of surface enhancement were analyzed: a surface with unevenly distributed minicavities and a surface coated with metallic powder applied by soldering. This paper analyzes the effects of the microstructured heated surface on the heat transfer coefficient. The results are presented as: relationships between the heat transfer coefficient and the vapor quality, boiling curves and two-phase flow images. The experimental data obtained for the two types of enhanced surfaces was compared with the results recorded for the smooth surface. The highest local values of the heat transfer coefficient were reported for the enhanced foil with minicavities.