Spin-Wave Optics in YIG Realized by Ion-Beam Irradiation

Direct focused-ion-beam writing is presented as an enabling technology for realizing functional spin-wave devices of high complexity, and demonstrate its potential by optically-inspired designs. It is shown that ion-beam irradiation changes the characteristics of yttrium iron garnet films on a submicron scale in a highly controlled way, allowing one to engineer the magnonic index of refraction adapted to desired applications. This technique does not physically remove material, and allows rapid fabrication of high-quality architectures of modified magnetization in magnonic media with minimal edge damage (compared to more common removal techniques such as etching or milling). By experimentally showing magnonic versions of a number of optical devices (lenses, gratings, Fourier-domain processors) this technology is envisioned as the gateway to building magnonic computing devices that rival their optical counterparts in their complexity and computational power.     

GARUSO: a gamification approach for involving stakeholders outside organizational reach in requirements engineering

Stakeholder participation is a key success factor of Requirements Engineering (RE). Typically, the techniques used for identifying and involving stakeholders in RE assume that stakeholders can be identified among the members of the organizations involved when a software system is ordered, developed or maintained—and that these stakeholders can be told or even mandated to contribute. However, these assumptions no longer hold for many of today’s software systems where significant stakeholders (in particular, end-users and people affected by a system) are outside organizational reach: They are neither known nor can they easily be identified in the involved organizations nor can they be told to participate in RE activities. We have developed the GARUSO approach to address this problem. It uses a strategy for identifying stakeholders outside organizational reach and a social media platform that applies gamification for motivating these stakeholders to participate in RE activities. In this article, we describe the GARUSO approach and report on its empirical evaluation. We found that the identification strategy attracted a crowd of stakeholders outside organizational reach to the GARUSO platform and motivated them to participate voluntarily in collaborative RE activities. From our findings, we derived a first set of design principles on how to involve stakeholders outside organizational reach in RE. Our work expands the body of knowledge on crowd RE regarding stakeholders outside organizational reach.

     

Social Capital,Resilience and Accessibility in Urban Systems: a Study on Sweden

Spatial systems appear to exhibit often a complex pattern of socio-economic development, in terms of (un)employment, income, mobility, ethnic composition, and urbanisation rates. Their evolution is co-determined by such factors as: market proximity, labour and housing market developments, public amenities, use of and access to transport systems, socio-economic composition of the population, etc. In addition, a sine qua non for sustaining urban economic growth is the local or regional presence of individual and collective cognitive assets that favour knowledge acquisition and transfer, education, innovation, and creativity. In this context, social capital and spatial accessibility are critical factors. The present paper aims to provide an operational framework for mapping out and understanding the mechanisms which drive spatial systems from the perspective of the resilience of urban areas, in the light of their social capital in combination with accessibility. Particular attention is therefore given to the essential role of social capital and transport accessibility in shaping both the economic development of cities and the spatial pattern in the evolution of cities, in terms of, inter alia, education, age, ethnic composition, (un)employment, and socio-economic poverty. For our quantitative analysis of the Swedish urban system, a quantile regression model is introduced and applied in order to study which urban-economic factors in Sweden determine the different levels of social capital, which are seen here as the fundamental component of the resilience capacity of urban areas.     

3D Printing and Nanotechnology: A Multiscale Alliance in Personalized Medicine

3D printing and nanotechnology have been two important tools in the development of therapeutic approaches for personalized medicine. More recently, their alliance has been improved in an effort to build innovative, versatile, multifunctional, and/or smart medical and pharmaceutical products. Therefore, an extensive review about scientific studies that ally 3D printing and nanomaterials in the development of new approaches for pharmaceutical and medical applications for the treatment and prevention of diseases is presented here. The articles are classified into five categories according to their main application: Cell growth and tissue engineering, antimicrobial, drug delivery, stimulus-response, and theranostics. Semisolid extrusion, inorganic nanoparticles, and cell growth and tissue engineering are the most reported 3D printing technique, type of nanomaterial, and application, respectively. The increase in papers dedicated to these areas is also notable, especially in the 2019 and 2020, when semisolid extrusion became the most used technique, overcoming fused deposition modelling. In fact, this review highlights that the possibility of an alliance between 3D printing and nanotechnology for the production of multiscale materials is undoubtedly a great opportunity for knowledge and innovation in the pharmaceutical and medical area.     

Formation of nanostructured epoxy networks containing polyhedral oligomeric silsesquioxane (POSS) blocks

Nanostructured epoxy networks, based on DGEBA and poly(oxypropylene)diamine (Jeffamine D), containing nano-sized inorganic blocks, polyhedral oligomeric silsesquioxanes (POSS), were investigated. The POSS were incorporated in the network as crosslinks or as pendant units by using octa- or monoepoxy-POSS monomers, respectively, as well as diepoxides with pendant POSS. The authors focused on investigating the relationship between the network formation process and the final product properties. The reactivity of the epoxy-functional POSS monomers, the hybrid systems' time of gelation, the gel fractions and the phase structure of the networks were determined using ¹H or ¹³C NMR spectroscopy, chemorheology experiments, sol-gel analysis and transmission electron microscopy (TEM).All the POSS epoxides tested show a reduced reactivity if compared to their respective model compounds due to sterical crowding in the neighborhood of their functional groups and due to reduced epoxy group mobility. The incorporation of pendant POSS into networks of the type DGEBA-Jeffamine D-monoepoxy-POSS hence took place only in the late reaction stage. Together with the high tendency of these POSS to aggregation, the kinetics favors the formation of small nano-phase-separated POSS domains, which act as physical crosslinks due to their covalent bonds to the organic matrix. At POSS loadings higher than 70%, topological constraint by POSS leads to a strongly reduced elastic chain mobility, thus additionally strongly reinforcing the networks. The network build-up and gelation of the octaepoxy-POSS-Jeffamine D system were slow compared to the reference DGEBA-Jeffamine D network due to a low octaepoxy-POSS reactivity and due to its strong tendency to cyclization reactions with primary amines. The topology of the amino groups is shown to be very important. In contrast to monoepoxy-POSS, the octaepoxy-POSS becomes dispersed as oligomeric junctions (purely chemical crosslinks) of the network in the cured product. The octaepoxide's reinforcing effect is small and is given only by its high functionality and not by its inorganic nature. The functionality effect is reduced by the mentioned cyclizations.     

Precise measurements of the total concentration of atmospheric CO2 and 13CO2/12CO2 isotopic ratio using a lead-salt laser diode spectrometer

We have developed a tunable diode laser spectrometer, called SIMCO (spectrometer for isotopic measurements of CO(2)), for determining the concentrations of (12)CO(2) and (13)CO(2) in atmospheric air, from which the total concentration of CO(2) and the isotopic composition (expressed in delta units) delta(13)CO(2) are calculated. The two concentrations are measured using a pair of lines around 2290.1 cm(-1), by fitting a line profile model, taking into account the confinement narrowing effect to achieve a better accuracy. Using the Allan variance, we have demonstrated (for an integration time of 25 s) a precision of 0.1 ppmv for the total CO(2) concentration and of 0.3[per thousand] for delta(13)CO(2). The performances on atmospheric air have been tested during a 3 days campaign by comparing the SIMCO instrument with a gas chromatograph (GC) for the measurement of the total CO(2) concentration and with an isotopic ratio mass spectrometer (MS) for the isotopic composition. The CO(2) concentration measurements of SIMCO are in very good agreement with the GC data with a mean difference of Delta(CO(2))=0.16+/-1.20 ppmv for a comparison period of 45 h and the linearity of the concentration between the two instruments is also very good (slope of correlation: 0.9996+/-0.0003) over the range between 380 and 415 ppmv. For delta(13)CO(2), the comparison with the MS data shows a larger mean difference of Delta(delta(13)CO(2))=(-1.9+/-1.2)[per thousand], which could be partly related to small residual fluctuations of the overall SIMCO instrument response.     

Targeting Serotonin 2A and Adrenergic α1 Receptors for Ocular Antihypertensive Agents: Discovery of 3,4‐Dihydropyrazino[1,2‐b]indazol‐1(2H)‐one Derivatives

Glaucoma affects millions of people worldwide and causes optic nerve damage and blindness. The elevation of the intraocular pressure (IOP) is the main risk factor associated with this pathology, and decreasing IOP is the key therapeutic target of current pharmacological treatments. As potential ocular hypotensive agents, we studied compounds that act on two receptors (serotonin 2A and adrenergic α₁) linked to the regulation of aqueous humour dynamics. Herein we describe the design, synthesis, and pharmacological profiling of a series of novel bicyclic and tricyclic N2‐alkyl‐indazole‐amide derivatives. This study identified a 3,4‐dihydropyrazino[1,2‐b]indazol‐1(2H)‐one derivative with potent serotonin 2A receptor antagonism, >100‐fold selectivity over other serotonin subtype receptors, and high affinity for the α₁ receptor. Moreover, upon local administration, this compound showed superior ocular hypotensive action in vivo relative to the clinically used reference compound timolol.     

Antagonistic effects on mechanical properties of microfibrillar composites with dual reinforcement: Explanation by FEA model of soft interface

Nanofillers (NF) in microfibrillar composites support melt‐drawing and may lead to improved performance. However, antagonistic effects have also been found. The deterioration of mechanical properties by drawing in the presence of NF, as found by other authors in analogous undrawn systems, has not yet been explained. Experiments indicating the importance of NF migration between the HDPE matrix and the PA6 fibrils in the course of drawing have led to a tentative conclusion of changed crystallinity in the interfacial area resulting in a layer with reduced modulus. This was confirmed by the finite element analysis considering the formation of a “soft” interface as a result of reduced content of HDPE spherulites at the fiber surfaces. The results show a marked impact of this phenomenon on modulus. This original concept presents a basis for explaining some antagonistic effects in multicomponent polymer systems and a tool for the more rational design of composite materials. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44712.     

Impact of particle morphology on structure,crystallization kinetics,and properties of PCL composites with TiO<Subscript>2</Subscript>-based particles

Crystallization kinetics of polycaprolactone (PCL) filled with TiO₂-based particles (TiX) was shown to depend on the TiX particle type and concentration, which were associated with a slight polymer matrix degradation. The partially degraded, shorter, and more mobile polymer chains increased the overall crystallization rate at the initial stage of crystallization, while at the later stages, the non-nucleating TiX particles acted as a sterical hindrance, slowing down the crystallization process. The PCL/TiX composites were prepared by melt-mixing and contained 2.5 and 5 wt% of the filler. The investigated TiX particles included isometric anatase microparticles (mTiO₂) and titanate nanotubes with high-aspect ratio (TiNT). Light and electron microscopy showed very homogeneous dispersion of the mTiO₂ particles in the PCL matrix, while the TiNT formed large agglomerates. In situ polarized light microscopy displayed faster isothermal crystallization of all PCL/TiX composites, but the micrographs indicated that the TiX particles did not act as nucleation centres. Isothermal DSC experiments, evaluated in terms of Avrami theory, confirmed the PLM results and showed that the overall rate of isothermal crystallization increased in the following order: PCL <PCL/TiNT <PCL/mTiO₂. Non-isothermal DSC and rheological measurements revealed the correlation between the crystallization rate and the polymer matrix degradation—the well-dispersed mTiO₂ particles with high specific surface caused the highest PCL degradation and, consequently, the earliest start of non-isothermal crystallization as well as the fastest isothermal crystallization. Microindentation hardness measurements confirmed that the partial degradation of the polymer matrix did not have a significant impact on the mechanical performance of PCL/mTiO₂ composites.