Development of a quantitative spectrophotometric assay for lectins

A new quantitative spectrophotometric assay for lectins has been developed. It involves mixing a copolymer with a lectin solution and measuring the absorbance change as a function of time as the resulting solution becomes turbid. The slope obtained could be correlated quantitatively with the amount of lectin present. The assay has sensitivity problems at low lectin concentrations and also a reproducibility problem. More study is required in these two areas

Correct-by-Construction Control Design for Mixed-Invariant Systems in Lie Groups

In this paper, we use the derivative of the exponential map to derive the exact evolution of the logarithm of the tracking error for mixed-invariant systems. Following correct-by-construction software paradigm, we propose an invariant control law for mixed-invariant systems, with application to Unmanned Aerial Systems (UASs), that is designed for efficient safety verification. We derive the nonlinear distortion matrix in the transformed differential equation in the Lie algebra and express the distortion matrix in a series form for any matrix Lie group and in a closed-form for the SE(2) Lie group. Given the input distortion, we employ dynamic inversion to linearize the evolution of error dynamics and apply a linear control strategy. We employ Linear Matrix Inequalities (LMIs) to bound the tracking error given a bounded disturbance amplified by the distortion matrix and leverage the tracking error bound to create flow pipes for the creation of a Polyhedral Invariant Hybrid Automaton (PIHA) model. We demonstrate the usefulness of our method by applying it to a simplified holonomic aircraft and nonholonomic rover with polynomial-based path planning methods.Comment: 15 pages, 19 figures. Submitted to IEEE TA

Evaluation of Material Shortage Effect on Assembly Systems Considering Flexibility Levels

The global pandemic caused delays in global supply chains, and numerous manufacturing companies are experiencing a lack of materials and components. This material shortage affects assembly systems at various levels: process level (decreasing of the resource efficiency), system level (blocking or s tarvation of production entities), and company level (breaking the deadlines for the supplying of the products to customers or retailers). Flexible assembly systems allow dynamic reactions in such uncertain environments. However, online scheduling algorithms of current research are not considering reactions to material shortages. In the present research, we aim to evaluate the influence of material shortage on the assembly system performance. The paper presents a discrete event simulation of an assembly system. The system architecture, its behavior, the resources, their capacities, and product specific operations are included. The material shortage effect on the assembly system is compensated utilizing different system flexibility levels, characterized by operational and routing flexibility. An online control algorithm determines optimal production operation under material shortage uncertain conditions. With industrial data, different simulation scenarios evaluate the benefits of assembly systems with varying flexibility levels. Consideration of flexibility levels might facilitate exploration of the optimal flexibility level with the lowest production makespan that influence further supply chain, as makespan minimization cause reducing of delays for following supply chain entities

Coulomb blockade and quantum tunnelling in the low-conductivity phase of granular metals

We study the effects of Coulomb interaction and inter-grain quantum tunnelling in an array of metallic grains using the phase-functional approach for temperatures $T$ well below the charging energy $E_{c}$ of individual grains yet large compared to the level spacing in the grains. When the inter-grain tunnelling conductance $g\gg1$, the conductivity $\sigma$ in $d$ dimensions decreases logarithmically with temperature ($\sigma/\sigma_{0}\sim1-\frac{1}{2\pi gd}\ln(gE_{c}/T)$), while for $g\to0$, the conductivity shows simple activated behaviour ($\sigma \sim \exp(-E_c/T)$). We show, for bare tunnelling conductance $g \gtrsim 1$, that the parameter $\gamma \equiv g(1-2/(g\pi)\ln(gE_{c}/T))$ determines the competition between charging and tunnelling effects. At low enough temperatures in the regime $1\gtrsim \gamma \gg 1/\sqrt{\beta E_{c}}$, a charge is shared among a finite number $N=\sqrt{(E_{c}/T)/\ln(\pi/2\gamma z)}$ of grains, and we find a soft activation behaviour of the conductivity, $\sigma\sim z^{-1}\exp(-2\sqrt{(E_{c}/T)\ln(\pi/2\gamma z)})$, where $z$ is the effective coordination number of a grain.Comment: 11 pages REVTeX, 3 Figures. Appendix added, replaced with published versio

Selbstständiges Lernen an der Hochschule: Diskussion eines computergestützten niedrigschwelligen Förderansatzes

Im Vergleich zur Schule ist das Lernen an der Hochschule durch deutlich größere Freiheitsgrade mit Bezug auf die Gestaltung des eigenen Lernhandelns geprägt. Diese seitens der Institution gegebenen Freiheitsgrade bedürfen aber auch größerer Verantwortung auf Seiten der Lernenden. Basierend auf theoretischen Modellvorstellungen zum Lernen als selbstregulierten Prozess gehen wir davon aus, dass Studierende ihr Lernhandeln im Hinblick auf bestimmte Ziele wie das Bestehen einer Modulabschlussprüfung systematisch verfolgen, indem siebeispielsweise Lehrveranstaltungen gezielt besuchen und diese vor- und nachbereiten. Um Studierende in ihrer Regulationdes Lernens zu unterstützen, wurde eine Webanwendung entwickelt, die Studierende anregen soll, veranstaltungsbegleitend ihr gelerntes Wissen zu überprüfen. Ergänzt wird dies durch Feedbackelemente, die eine Reflexion über das eigene Lernhandeln und den eigenen Wissenstand anregen sollen. Neben dem theoretischen Hintergrund soll in diesem Beitrag eine erste computergestützte Umsetzung dieser Ideen dargestellt werden. Darüber hinaus werden formative Evaluationsergebnisse aus der Pilotphase vorgestellt und mit Blick auf die Weiterentwicklung dieses Programms diskutiert.In comparison to school, students in higher education settings enjoy considerably more degrees of freedom with regard to the regulation of their learning. However, more degrees of freedom on the one side require to take more responsibility for one's own learning on the other side. Based on theoretical models of self-regulated learning, we assume that students tend to plan their learning systematically in order to reach individual goals, for example to pass a specific exam. Furthermore, students monitor and reflect on their learning behavior. In order to support university students in the regulation of their learning activities, we developed a computer supported tool, which aims to regularly test student's knowledge. Furthermore, feedback with regard to the learning outcomes and learning behavior is provided. This paper delineates the theoretical background that led to the development of a new computer-supported tool aiming to promote student's self-regulated learning. Furthermore, core functions of this tool are described. Finally, we will summarize firstdata of a formative evaluation and discussfurther development of this tool

Electron dephasing near zero temperature: an experimental review

The behavior of the electron dephasing time near zero temperature, $\tau_\phi^0$, has recently attracted vigorous attention. This renewed interest is primarily concerned with whether $\tau_\phi^0$ should reach a finite or an infinite value as $T \to$ 0. While it is accepted that $\tau_\phi^0$ should diverge if there exists only electron-electron (electron-phonon) scattering, several recent measurements have found that $\tau_\phi^0$ depends only very weakly on temperature, if at all, when $T$ is sufficiently low. This article discusses the current experimental status of "the saturation problem", and concludes that the origin(s) for this widely observed saturation are still unresolved

Protein corona and nanoparticles: How can we investigate on?

Nanoparticles (NPs) represent one of the most promising tools for drug-targeting and drug-delivery. However, a deeper understanding of the complex dynamics that happen after their in vivo administration is required. Particularly, plasma proteins tend to associate to NPs, forming a new surface named the 'protein corona' (PC). This surface is the most exposed as the 'visible side' of NPs and therefore, can have a strong impact on NP biodistribution, targeting efficacy and also toxicity. The PC consists of two poorly delimited layers, known as 'hard corona' (HC) and 'soft corona' (SC), that are affected by the complexity of the environment and the formed protein-surface equilibrium during in vivo blood circulation. The HC corona is formed by proteins strongly associated to the NPs, while the SC is an outer layer consisting of loosely bound proteins. Several studies attempted to investigate the HC, which is easier to be isolated, but yielded poor reproducibility, due to varying experimental conditions. As a consequence, full mapping of the HC for different NPs is still lacking. Moreover, the current knowledge on the SC, which may play a major role in the 'first' interaction of NPs once in vivo, is very limited, mainly due to the difficulties in preserving it after purification. Therefore, multi-disciplinary approaches leading to the obtainment of a major number of information about the PC and its properties is strongly needed to fully understand its impact and to better support a more safety and conscious application of nanotechnology in medicine

The classic Lower Devonian plant-bearing deposits of northern New Brunswick, eastern Canada: Dispersed spore taxonomy and biostratigraphy

This paper describes dispersed spore assemblages recovered from the Lower Devonian Val d'Amour and Campbellton formations exposed along the Restigouche River in northern New Brunswick, eastern Canada. The dispersed spore assemblages were recovered from seven of the nine sampled sections and biostratigraphical analysis suggests that these can be assigned to the polygonalis–emsiensis, annulatus–sextantii and douglastownense–eurypterota Spore Assemblage Biozones. This indicates that these strata range in age from Pragian to late Emsian [or possibly earliest Eifelian]. The new biostratigraphical control enables accurate stratigraphical correlation of the nine sections and provides important age constraints for the famous early land plant megafossil and non-marine invertebrate/vertebrate assemblages recovered from these strata. Two new dispersed spore species are described: Emphanisporites genselae sp. nov. and Emphanisporites morrisae sp. nov