Self-organization of intrinsically disordered proteins with folded N-termini

Thousands of human proteins lack recognizable tertiary structure in most of their chains. Here we hypothesize that some use their structured N-terminal domains (SNTDs) to organise the remaining protein chain via intramolecular interactions, generating partially structured proteins. This model has several attractive features: as protein chains emerge, SNTDs form spontaneously and serve as nucleation points, creating more compact shapes. This reduces the risk of protein degradation or aggregation. Moreover, an interspersed pattern of SNTD-docked regions and free loops can coordinate assembly of sub-complexes in defined loop-sections and enables novel regulatory mechanisms, for example through posttranslational modifications of docked regions

Assessment of Cognitive Strain in Digital Logistics Work: Background, Analysis and Implications

Digital logistics processes are not only a technological challenge. In addition, the question of human cognitive strain and human-computer interaction are important success factors for digital logistics work concepts. After a background introduction, conceptual and an analytical frameworks for identifying cognitive strain in digital logistics work are presented and applied to specific logistics activities. Characteristic features are the speed and density of work tasks, the requirement for teamwork and inter-organizational cooperation as well as the important role of motivation in the “people business” of logistics. Further research is warranted regarding the specific characteristics of digital logistics work and the impact on cognitive workload of human workers

Wakefield-Induced Ionization injection in beam-driven plasma accelerators

We present a detailed analysis of the features and capabilities of Wakefield-Induced Ionization (WII) injection in the blowout regime of beam driven plasma accelerators. This mechanism exploits the electric wakefields to ionize electrons from a dopant gas and trap them in a well-defined region of the accelerating and focusing wake phase, leading to the formation of high-quality witness-bunches [Martinez de la Ossa et al., Phys. Rev. Lett. 111, 245003 (2013)]. The electron-beam drivers must feature high-peak currents ($I_b^0\gtrsim 8.5~\mathrm{kA}$) and a duration comparable to the plasma wavelength to excite plasma waves in the blowout regime and enable WII injection. In this regime, the disparity of the magnitude of the electric field in the driver region and the electric field in the rear of the ion cavity allows for the selective ionization and subsequent trapping from a narrow phase interval. The witness bunches generated in this manner feature a short duration and small values of the normalized transverse emittance ($k_p\sigma_z \sim k_p\epsilon_n \sim 0.1$). In addition, we show that the amount of injected charge can be adjusted by tuning the concentration of the dopant gas species, which allows for controlled beam loading and leads to a reduction of the total energy spread of the witness beams. Electron bunches, produced in this way, fulfil the requirements to drive blowout regime plasma wakes at a higher density and to trigger WII injection in a second stage. This suggests a promising new concept of self-similar staging of WII injection in steps with increasing plasma density, giving rise to the potential of producing electron beams with unprecedented energy and brilliance from plasma-wakefield accelerators

Impurity intrusion in radio-frequency micro-plasma jets operated in ambient air

Space and time resolved concentrations of helium metastable atoms in an atmospheric pressure radio-frequency micro-plasma jet were measured using tunable diode laser absorption spectroscopy. Spatial profiles as well as lifetime measurements show significant influences of air entering the discharge from the front nozzle and of impurities originating from the gas supply system. Quenching of metastables was used to deduce quantitative concentrations of intruding impurities. The impurity profile along the jet axis was determined from optical emission spectroscopy as well as their dependance on the feed gas flow through the jet.Comment: Journal of Physics D: Applied Physics (accepted), 6 page

Is TNF-α a prognostic factor in patients with sepsis?

Objective: To determine tumor necrosis factor-α (TNF-α) levels in a prospective study in 58 hospitalized patients in a department of internal medicine (63 episodes, 29 in immunocompromised patients) during a 7-month period.Methods: Patients fulfilling the following criteria were included: clinical evidence of acute infection, temperature >38.2°C, tachycardia >90 beats/min, tachypnea >20 breaths/min. Samples were taken from day 1 up to day 13 after an infection was diagnosed, and TNF-α was determined by enzyme immunoassay.Results: In 29 episodes (46.0%) the infection was microbiologically documented. The median of the TNF-α levels in the Gram-negative episodes was significantly higher than that in the Gram-positive episodes (p = 0.002). Thirteen of 63 episodes (20.6%) had a fatal outcome. With respect to all measured values, the non-survivors had a significantly higher median of TNF-α levels than the survivors (p = 0.0001). There was, however, great interpatient and intrapatient variability in TNF-α levels; thus, no unequivocal correlation between TNF-α and outcome could be documented.Conclusions: Our data indicate that the influence of the infecting organism on TNF-α kinetics is less pronounced than that of the underlying disease

Rollenerwartungen unterschiedlicher Berufsgruppen im OP

Zusammenfassung: Hintergrund: Ausdifferenzierte Rollenstrukturen haben den Vorteil, dass sie den Teammitgliedern vorgeben, welches Verhalten von ihnen erwartet wird bzw. welches Verhalten sie von den anderen Mitgliedern erwarten können. Die Entstehung einer solchen Rollenstruktur erfordert jedoch eine Vielzahl an Interaktionen der betreffenden Menschen und somit eine Mindestkontaktdauer. Im OP-Saal arbeiten die Teams meist in wechselnder Zusammensetzung. In diesen kurzfristig zusammengestellten Teams kann sich eine Rollenstruktur nicht ausdifferenzieren. In der vorliegenden Untersuchung wird der Frage nachgegangen, ob die Zugehörigkeit zu einer bestimmten Berufsgruppe die fehlende Möglichkeit zur häufigen Interaktion im OP-Bereich substituiert. Methode: Anhand eines 9-Item-Fragebogens zur sozialperspektivischen Imagepositionierung (Kurzform von SYMLOG) wurden in einer schriftlichen Befragung OP-Saal-Mitarbeiter aus zwei Krankenhäusern zu ihrer Einschätzung von professionsspezifischen Verhaltensmerkmalen bezüglich Einfluss, Sympathie und Zielorientierung befragt (n=179). Ergebnisse: Die jeweiligen Berufsgruppen beurteilen sich selbst in der Eigenbewertung in jeder der 3Dimensionen höher, als sie die beiden anderen Professionen in der Fremdbeurteilung bewerten. Die Fremdbewertungen können jedoch den Wert der Eigenbewertung übersteigen. Die Analyse der Rollenwahrnehmung zeigt auf, dass sich beide akademischen Berufsgruppen einen großen Einfluss und eine große Zielorientierung zuschreiben. Hieraus kann ein Führungsanspruch abgeleitet werden, der ein Konfliktpotenzial beinhalten könnte. Diskussion: Die Datenanalyse zeigt, dass im untersuchten Kollektiv eine ausdifferenzierte Rollenstruktur im OP-Saal nicht vorhanden war. Hieraus lassen sich Optimierungsmöglichkeiten ableiten, wie beispielsweise der verstärkte Einsatz eingespielter Teams oder die Implementierung Konflikt reduzierender Methode

In Vitro Formation of Urinary Stones : Generation of Spherulites of Calcium Phosphate in Gel and Overgrowth with Calcium Oxalate Using a New Flow Model of Crystallization

Calcium phosphate (CaP) has been detected in the majority of urinary stones containing predominantly calcium oxalate (CaOx). Therefore, crystal phases of CaP might play an important role with respect to the formation of urinary calcium stones in general. Very often, CaP found in stones or tissue of human kidney occurs in the shape of small spherulites. In this paper, we report on a new flow model of crystallization (FMCG), which has been used to generate spherulites of CaP in a gel matrix of 1% agar-agar at 37°C from a supersaturated, metastable solution continuously flowing over the gel surface. Scanning electron microscopy (SEM), X-ray diffraction and microscopic Fourier transformed infrared spectroscopy (FTIR) revealed that the particles formed (diameter: up to 200 μm) consisted of a poorly crystal-line core of carbonatoapatite which was partly surrounded by a well-crystallized shell of octacalcium phosphate (OCP) showing radially oriented sheet-like structures. Subsequently, CaOx was grown on these spherulites from a flow of a correspondingly supersaturated solution conducted over the gel matrix. It could be shown by SEM that growth of calcium oxalate monohydrate (COM) was characteristically induced by the OCP shell. Radial sheet-like forms of OCP were directly continued by COM showing a certain radial orientation. The model of crystallization in gel matrices applied here should be well-suited to simulate the process of urinary stone formation under in vitro conditions

Linkage disequilibrium under recurrent bottlenecks

Understanding patterns of selectively neutral genetic variation is essential in order to model deviations from neutrality, caused for example by different forms of selection. Best understood is neutral genetic variation at a single locus, but additional insights can be gained by investigating genetic variation at multiple loci. The corresponding patterns of variation reflect linkage disequilibrium and provide information about the underlying multi-locus gene genealogies. The statistical properties of two-locus genealogies have been intensively studied for populations of constant census size, as well as for simple demographic histories such as exponential population growth, and single bottlenecks. By contrast, the combined effect of recombination and sustained demographic fluctuations is poorly understood. Addressing this issue, we study a two-locus Wright-Fisher model of a population subject to recurrent bottlenecks. We derive coalescent approximations for the covariance of the times to the most recent common ancestor at two loci. We find, first, that an effective population-size approximation describes the numerically observed linkage disequilibrium provided that recombination occurs either much faster or much more slowly than the population size changes. Second, when recombination occurs frequently between bottlenecks but rarely within bottlenecks, we observe long-range linkage disequilibrium. Third, we show that in the latter case, a commonly used measure of linkage disequilibrium, sigma_d^2 (closely related to r^2), fails to capture long-range linkage disequilibrium because constituent terms, each reflecting long-range linkage disequilibrium, cancel. Fourth, we analyse a limiting case in which long-range linkage disequilibrium can be described in terms of a Xi-coalescent process allowing for simultaneous multiple mergers of ancestral lines.Comment: 34 pages, 7 figure