Photonic Fractal Metamaterials: A Metal–Semiconductor Platform with Enhanced Volatile-Compound Sensing Performance

Advance of photonics media is restrained by the lack of structuring techniques for the 3D fabrication of active materials with long-range periodicity. A methodology is reported for the engineering of tunable resonant photonic media with thickness exceeding the plasmonic near-field enhancement region by more than two orders of magnitude. The media architecture consists of a stochastically ordered distribution of plasmonic nanocrystals in a fractal scaffold of high-index semiconductors. This plasmonic-semiconductor fractal media supports the propagation of surface plasmons with drastically enhanced intensity over multiple length scales, overcoming the 2D limitations of established metasurface technologies. The fractal media are used for the fabrication of plasmonic optical gas sensors, achieving a limit of detection of 0.01 vol% at room temperature and sensitivity up to 1.9 nm vol%⁻¹, demonstrating almost a fivefold increase with respect to an optimized planar geometry. Beneficially to their implementation, the self-assembly mechanism of this fractal architecture allows fabrication of micrometer-thick media over surfaces of several square centimeters in a few seconds. The designable optical features and intrinsic scalability of these photonic fractal metamaterials provide ample opportunities for applications, bridging across transformation optics, sensing, and light harvesting.     

A modified technique for the impregnation of lanthanum tracer to study the integrity of tight junctions on cells grown on a permeable substrate

Ionic lanthanum is commonly used to trace permeability pathways across epithelia and endothelia in biological electron microscopy. A method for obtaining a uniformly dense precipitate of lanthanum is described. The method, which is a modification of the technique described by Shaklai and Tavassoli (1977) was suitable for fixation of cell cultures grown on permeable filter inserts and was successfully applied to study opening of tight junctions by hypertonic solutions in the airway epithelial cell line 16HBE14o(-). The preparation method formed the basis for a semiquantitative morphological determination in which the tight junctions were subdivided as "intact," "weakened," and "open." By using this modified technique, it could be demonstrated that opening of tight junctions in airway epithelial cells increased, with increasing osmolarity with electrolytes having a stronger effect than nonelectrolytes. A significant linear relationship was found between the osmolarity of the medium and the open state of the tight junctions (as determined by the semiquantitative morphological technique) or the transepithelial electrical resistance.     

Model testing of fixture–workpiece interface compliance in dynamic conditions

This paper is focused on the problem of compliance of interface between clamping/locating fixture elements and workpiece, under dynamic loads during machining. In contrast to previous investigations, the authors have developed a special device dedicated to testing of physical models which represent clamping/locating elements and workpiece. This device allows optimization of a large number of input parameters which are critical to interface compliance. It was used in experimental investigations to establish the impact that the radius of the spherical tip of a clamping/locating element has on the interface compliance and load capacity. The results of experimental investigation show that, under certain conditions, the clamping/locating elements with larger-radius spherical tips provide significantly lower interface compliance. Future investigations should be aimed at finding optimum macro- and micro-geometries of contact interface, as well as the selection of materials for clamping/locating elements.     

Reversible Image Contrast Manipulation with Thermally Tunable Dielectric Metasurfaces

Increasing demand for higher resolution of miniaturized displays requires techniques achieving high contrast tunability of the images. Employing metasurfaces for image contrast manipulation is a new and rapidly growing field of research aiming to address this need. Here, a new technique to achieve image tuning in a reversible fashion is demonstrated by dielectric metasurfaces composed of subwavelength resonators. It is demonstrated that by controlling the temperature of a metasurface the encoded transmission pattern can be tuned. To this end, two sets of nanoresonators composed of nonconcentric silicon disks with a hole that exhibit spectrally sharp Fano resonances and forming a Yin‐Yang pattern are designed and fabricated. Through exploitation of the thermo‐optical properties of silicon, full control of the contrast of the Yin‐Yang image is demonstrated by altering the metasurface temperature by ΔT ≈ 100 °C. This is the first demonstrated technique to control an image contrast by temperature. Importantly, the turning technique does not require manipulating the external stimulus, such as polarization or angle of the illumination and/or the refractive index of this environment. These results open many opportunities for transparent displays, optical switches, and tunable illumination systems.     

Fischer–Tropsch Synthesis: Differences Observed in Local Atomic Structure and Selectivity with Pd Compared to Typical Promoters (Pt, Re, Ru) of Co/Al2O3 Catalysts

Pd was examined as a promoter for Fischer?CTropsch synthesis, and its effects on cobalt oxide reduction and product selectivities relative to commonly used promoters (i.e., Pt, Re, and Ru) at atomically equivalent levels were compared. Pd was identified to promote cobalt oxide reduction to even lower temperatures than Pt and Ru. However, Pd addition deleteriously affected product selectivity, and a clear shift to favor light products was observed. XANES analysis of an activated model catalyst revealed that Pd was in the reduced state. Local atomic structure was examined by EXAFS. Unlike Pt, Re, and Ru promoters, where previous investigations by groups such as Dr. Guczi??s and ours have only observed coordination of the promoter with cobalt, Pd displayed both direct coordination to Co as well as other Pd atoms. The results suggest that this feature may be responsible for the measurably higher light gas selectivities observed.     

Implementation of W-CDMA Cell Search on a Highly Parallel and Scalable MPSoC

The performance of the W-CDMA cell search algorithm can be significantly improved using homogeneous general purpose Multi-Processor System-on-Chip (MPSoC) architectures. The application also scales well, as the number of processing nodes increases, allowing practical accelerations to become close to the theoretical maximum. In this work we describe a template MPSoC architecture based on multiprocessor computational clusters, called Ninesilica. Each Ninesilica consist of nine processing nodes based on COFFEE RISC architecture. MPSoC inter- and intra-cluster communication are enabled using hierarchical Network-on-Chip with dedicated point to point and broadcast communication services for better performance. Proposed template has been used to instantiate complete systems with one and four Ninesilica clusters, resulting in MPSoCs with respectively 9 and 36 computational nodes. The MPSoCs have been physically prototyped on a FPGA device, and the W-CDMA cell search algorithm has been mapped on both MPSoC platforms. The four Ninesilica MPSoC can execute W-CDMA in 20.5 ms (at 115 MHz, slow mode implementation) with the total speed-up of 24.3X and 3.3X when compared to a single processing core system and to a single Ninesilica cluster, respectively.     

A Data-Mining Approach for Investigating Social and Economic Geographical Dynamics of $beta$-Thalassemia's Spread

beta-Thalassemia is an anemic genetic disorder that remains a major global health issue, especially in the globalized era where public health, economics, and education are tightly interwoven. Previous studies have examined the disease's rate and heredity. This study analyzed beta-thalassemia's socioeconomic geography and how it affects the afflicted population. We processed survey data and performed data mining using self-organizing maps to identify underlying data structure. We hypothesized that certain variables mark subgroups within the affected population and we aimed at identifying these subgroups and used a correlation-based measure to assess the variable's importance to the subgroup's distinction. The population's education level was one of the major factors that divided it into different subgroups. Our study showed that recurring patterns of specific variables separated the affected population into disparate subgroups based on their response to questionnaires. Future studies can use such tools to delve deeper into how other variables (e.g. socioeconomic and genomic) can identify subgroups within larger affected populations.     

Hierarchy of maturation parameters in oil-source rock correlations. Case study: Drmno depression, Southeastern Pannonian Basin, Serbia and Montenegro

Hierarchy of triterpane, sterane, naphthalene and phenanthrene maturation parameters in oil-source rock correlations (Drmno depression, southeastern part of the Pannonian Basin, Serbia and Montenegro) was evaluated. Different triterpane and sterane parameters were found to be very similar in all investigated samples. Phenanthrene and naphthalene maturation parameters demonstrated much less uniformity, and thus higher applicability. In order to establish a detailed hierarchy of these maturation parameters, the factor analysis was used. Parameters based on isomerization reactions (α → β) of methylnaphthalenes and methylphenanthrenes, having high loadings, defined the statistically most significant factor 1. Parameters based on dealkylation processes of dimethyl- and trimethylphenanthrenes into methylphenanthrenes, having extremely high loadings values, determined factor 2. In the last significant, factor 3, high loadings were observed with triterpane and sterane parameters. The factor analysis involving just the phenanthrene and naphthalene isomerization parameters, classified methylphenanthrene isomerization parameters into factor 1. Among the naphthalene isomerization maturation parameters a certain hierarchy was also observed, which depended on whether the parameters represented isomer ratios which differed on the position of one or two alkyl groups. General conclusion based on factor analysis is in agreement with theoretical presumptions concerning the transformations of phenanthrene and naphthalene isomers.     

Fibrinolysis during pregnancy. The pre- and postpartal changes

Our previous research as well as data in literature (Yuasas, Ishizawa M.--1992) emphasised increased plasma fibrinolytic activity (PFA) in women during labor. Starting from these data we have tried to observe plasma fibrinolytic activity studied through euglobulin lysis time (ELT) in women during pregnancy and after delivery. We studied 25 healthy pregnant women aged between 18 and 30 years which were tested in the seventh month, during labour and at 48 hours after delivery. Blood samples were taken from the antecubital vein by venous puncture. The study showed an increased PFA (shortened ELT) only during labor; in the seventh month and at 48 hours after delivery ELT had almost the same values.