Quantitative analysis of Förster resonance energy transfer from spectrally resolved fluorescence measurements

Die Arbeit beschreibt eine neuartige Methode zur Analyse von "Förster Energie-Transfer (FRET)"Signalen. Die Methode stellt eine allgemeine Lösung für Schätzwerte der apparenten FRET-Effizienz bereit, die sich entweder auf Fluoreszenzlöschung des Donors oder auf sensibilisierte Fluoreszenz des Akzeptors beziehen. Daneben werden Schätzwerte für die Gesamtkonzentration von Donor und Akzeptor geliefert. Die eventuelle Gegenwart von freien Donor- und Akzeptorfluorophoren wird berücksichtigt. Korrekturen für das Übersprechen zwischen spektralen Komponenten - sowohl was Anregung als auch was Emission betrifft - sind integrale Bestandteile der Methode. Eine Realisierung der Methode am Spektralphotometer zeigt auf, dass zwei der häufigsten Fehlerquellen von FRET-Messungen identifiziert und korrigiert werden können: Bleichung und Protonierung der Fluorophoren. Weitere Anwendungen der Methode zeigen ihr Potential molekulare Interaktionen quantitativ auszuwerten. Für die Anwendung in der Mikroskopie wird zusätzlich eine Analyse des Photonenrauschens geliefert, sowie die Fehlerfortpflanzung behandelt, was das Signal-Rausch-Verhötnis der FRET-Schätzwerte betrifft. Es werden Modelle berechnet, welche das Signal-Rausch-Verhältnis als eine Funktion der Anzahl der detektierten Photonen beschreiben und die Optimierung der Effizienz in der Verwertung der beobachteten `Photone erlauben. Als Anwendung der Methode werden dynamische Veränderungen in der Konzentration von cAMP beschrieben, wobei ein EPAC-basierter FRET-Sensor eingesetzt wird. Es wird gezeigt, dass Einflüsse auf das Signal-Rausch-Verhältnis der FRET- Messungen, wie sie durch Bleichen und Veränderung der FRET-Effizienz bewirkt werden, korrekt vorhergesagt werden können

GENDER AND NETWORKING: BUILDING AND BENEFITING FROM HIGH STATUS TIES IN THE WORKPLACE

While organizations have significantly reduced the overt and intentional forms of sex discrimination that impeded women’s careers in the past, a great deal of research suggests women continue to face informal barriers in the workplace. One such arena in which women tend to be disadvantaged is in their workplace networks. In many ways, men and women have similar networks, yet women are less likely than their male counterparts to have personal relationships with high status coworkers. Scholars have long suggested that these strategic connections are valuable and may be especially beneficial to or necessary for women. Networking has long been touted as one way women can overcome workplace disadvantage by strategically developing and/or capitalizing on such networks, which can enable their success and satisfaction at work. However, networking is a considerable investment. Indeed, networking has been called women’s third shift, after work and family responsibilities. As such, it is vital that we understand how women and men can best capitalize on their investments in networking. This research seeks to add to our scholarly understanding by examining the extent to which men and women can translate their networking behaviors into high status connections and capitalize on those connections to enhance their performance and job satisfaction. Results suggest networking behaviors enable men and women to have friends with higher informal status. However, while men’s networking behaviors are related to having higher ranking (formal status) friends, women’s networking behaviors are related to having lower ranking friends. Post-hoc analyses begin to explore the possibility that these gender differences are due to choices made by or others’ reactions to male and female networkers. Results also distinguish between employees’ gender and legitimacy to shed light on how and why men and women can develop and capitalize on high status connections, providing practical implications for employees and organizations seeking to intervene to enable women and men to develop high status connections. This research uses multimethod data to illuminate ways in which both women and men can translate their networking behaviors into high status connections, workplace performance, and job satisfaction

Internet Addiction and the Relationship to Self and Interpersonal Functioning Within the Alternative Model for Personality Disorders (AMPD): Implications for Psychosocial Development

Internet addictive use inclusive of inextricably interconnected mobile devices, applications, and social media predicts diminished Self and Interpersonal functioning. Internet addiction research is burdened by conflicting theoretical views, lack of standardized definitions and criteria, and the use of assessment measures adapted from those used for substance use disorders. Alternative and dimensional diagnostic models for internet addiction through a psychosocial developmental lens might further understanding of Internet addiction and reduce challenges which impact the ability to advance research and achieve clinically useful, culturally informed, and evidence-based practices for the assessment and treatment of Internet addiction

Superpriming of synaptic vesicles as a common basis for intersynapse variability and modulation of synaptic strength.

Glutamatergic synapses show large variations in strength and short-term plasticity (STP). We show here that synapses displaying an increased strength either after posttetanic potentiation (PTP) or through activation of the phospholipase-C-diacylglycerol pathway share characteristic properties with intrinsically strong synapses, such as (i) pronounced short-term depression (STD) during high-frequency stimulation; (ii) a conversion of that STD into a sequence of facilitation followed by STD after a few conditioning stimuli at low frequency; (iii) an equalizing effect of such conditioning stimulation, which reduces differences among synapses and abolishes potentiation; and (iv) a requirement of long periods of rest for reconstitution of the original STP pattern. These phenomena are quantitatively described by assuming that a small fraction of "superprimed" synaptic vesicles are in a state of elevated release probability (p ∼ 0.5). This fraction is variable in size among synapses (typically about 30%), but increases after application of phorbol ester or during PTP. The majority of vesicles, released during repetitive stimulation, have low release probability (p ∼ 0.1), are relatively uniform in number across synapses, and are rapidly recruited. In contrast, superprimed vesicles need several seconds to be regenerated. They mediate enhanced synaptic strength at the onset of burst-like activity, the impact of which is subject to modulation by slow modulatory transmitter systems

Klipsun Magazine 2002, Volume 32, Issue 06 - September

https://cedar.wwu.edu/klipsun_magazine/1215/thumbnail.jp

Klipsun Magazine, 2002, Volume 32, Issue 05 - June

https://cedar.wwu.edu/klipsun_magazine/1214/thumbnail.jp

The Meaning of Time: An Introduction into Philosophical, Biological and Physical Aspects of Time

This report presents an introduction into philosophy, biology astrophysics and other physical sciences as they relate to time. Time in man's basic experience, symbolizations of time, the western view of historical time and the evolution of the concept of time in philosophy are outlined. A brief introduction to biological clocks, chemical oscillations, biochemical cycles, and speculations about the human time sense follow. The major portion of the report deals with the search for the arrow of time in nature from physics. Absolute time in Newtonian physics, time in special relativity and the time inversion invariance of physical laws, appears to leave no room for an arrow of time in nature. Even the concept of entropy and the second law of thermodynamics are found not to be grounded in the laws of nature themselves but rather in the initial conditions of time evolving systems. The search for the origin of the arrow of time leads to the big bang origin of the universe which has a very low entropy state. The proper description of the evolution of the universe in terms of general relativity shows that time cannot be a dimension external to the universe but appears as an internal evolution parameter in recent attempts in the literature to give a cosmological description of the origin of the universe using the quantum theoryNaval Postgraduate School, Monterey, CAhttp://archive.org/details/meaningoftimeint00woehNaval Postgraduate School, Monterey, CANAApproved for public release; distribution is unlimited