Catalytic constants enable the emergence of bistability in dual phosphorylation

Dual phosphorylation of proteins is a principal component of intracellular signalling. Bistability is considered an important property of such systems and its origin is not yet completely understood. Theoretical studies have established parameter values for multistationarity and bistability for many types of proteins. However, up to now no formal criterion linking multistationarity and bistability to the parameter values characterizing dual phosphorylation has been established. Deciding whether an unclassified protein has the capacity for bistability, therefore requires careful numerical studies. Here, we present two general algebraic conditions in the form of inequalities. The first employs the catalytic constants, and if satisfied guarantees multistationarity (and hence the potential for bistability). The second involves the catalytic and Michaelis constants, and if satisfied guarantees uniqueness of steady states (and hence absence of bistability). Our method also allows for the direct computation of the total concentration values such that multistationarity occurs. Applying our results yields insights into the emergence of bistability in the ERK–MEK–MKP system that previously required a delicate numerical effort. Our algebraic conditions present a practical way to determine the capacity for bistability and hence will be a useful tool for examining the origin of bistability in many models containing dual phosphorylation.     

A Comprehensive Review of Genetically Engineered Mouse Models for Prader-Willi Syndrome Research

Prader-Willi syndrome (PWS) is a neurogenetic multifactorial disorder caused by the deletion or inactivation of paternally imprinted genes on human chromosome 15q11-q13. The affected homologous locus is on mouse chromosome 7C. The positional conservation and organization of genes including the imprinting pattern between mice and men implies similar physiological functions of this locus. Therefore, considerable efforts to recreate the pathogenesis of PWS have been accomplished in mouse models. We provide a summary of different mouse models that were generated for the analysis of PWS and discuss their impact on our current understanding of corresponding genes, their putative functions and the pathogenesis of PWS. Murine models of PWS unveiled the contribution of each affected gene to this multi-facetted disease, and also enabled the establishment of the minimal critical genomic region (PWScr) responsible for core symptoms, highlighting the importance of non-protein coding genes in the PWS locus. Although the underlying disease-causing mechanisms of PWS remain widely unresolved and existing mouse models do not fully capture the entire spectrum of the human PWS disorder, continuous improvements of genetically engineered mouse models have proven to be very powerful and valuable tools in PWS research.     

Repeated thermo-hydrolytic disintegration of medium density fibreboards (MDF) for the production of new MDF

European Journal of Wood and Wood Products - Medium density fibreboards (MDF) are currently not recycled after service life, but various publications report on recycling by the disintegration of...     

BioPACE

While developing the specifications for electronically enabled Machine Readable Travel Documents, the ICAO paid significant attention to security aspects related to the digital information stored in this type of electronic document. This has resulted in Passive and Active Authentication, Basic Access Control and Extended Access Control. The goal of Basic Access Control (BAC) is preventing unauthorized access to the chip data stored on eMRTDs. The PACE protocol has been developed as a future-proof method to overcome the limitations of BAC and to replace BAC in the future. In this paper the BioPACE protocol is proposed as a supplement to the PACE protocol. Besides verifying if the document holder is indeed the rightful owner, the BioPACE protocol provides a higher convenience for the bearer of the document.     

Universal access to awareness information: using smart artefacts to mediate awareness in distributed teams

This paper presents a set of design recommendations for team awareness systems based on fundamental social and technical requirements. The work was motivated by recurring usability problems identified in evaluations of state-of-the-art awareness systems. Based on these findings, it is argued that the limited success of existing systems is mostly caused by conceptual shortcomings, which can be overcome by adhering to a set of design recommendations elaborated in this paper. To demonstrate the validity of this argumentation, the development and evaluation of an ambient awareness system is illustrated.     

Design characteristics of a workload manager to aid drivers in safety–critical situations

Cognition, Technology & Work - The objective of this study was to evaluate a workload manager designed to supervise the presentation of in-vehicle information for two age groups of drivers...     

Gas/liquid oxygen-transfer to flowing lead alloys

For the application of liquid lead or lead-bismuth eutectic as coolant in nuclear reactors, the concentration of dissolved oxygen, determining the compatibility with steels used as construction materials, is of critical importance. In general, oxygen has to be added continuously to the liquid metal, so as to compensate for consumption by oxide formation on the surface of the reactor components. A potential method of keeping the oxygen concentration in a favourable range is transferring oxygen from an oxygen-containing gas, which is investigated on the basis of the experience from operating a gas/liquid transfer device in the CORRIDA loop. Conclusions on oxygen transfer in industrial-scale systems are drawn.     

Flash Sintering of Nanocrystalline Zinc Oxide and its Influence on Microstructure and Defect Formation

We report the sintering behavior of nanocrystalline zinc oxide under external AC electric field between 0 and 160 V/cm. In situ acquisition of density by means of laser dilatometry, evaluation of specimen temperature, real‐time measurement of electric field and current help analyze this peculiar behavior. Field strength and blocking electrodes significantly affect densification and microstructure, which was evaluated in the vicinity of the flash event and for the fully sintered material. High current densities flow through the sample at high electric fields, entailing a sudden increment of the temperature estimated to several hundreds of K and an exaggerated grain growth. In contrast, low current density flows through the sample at lower electric fields, which guarantees normal grain growth and highest final density. Macroscopic photoluminescence measurements give insights into the development of the defect structure. Electric fields are expected to enhance defect mobility, explaining the high densification rates observed during the sintering process.