Bronchospasm and its Biophysical Basis in Airway Smooth Muscle

Airways hyperresponsiveness is a cardinal feature of asthma but remains unexplained. In asthma, the airway smooth muscle cell is the key end-effector of bronchospasm and acute airway narrowing, but in just the past five years our understanding of the relationship of responsiveness to muscle biophysics has dramatically changed. It has become well established, for example, that muscle length is equilibrated dynamically rather than statically, and that non-classical features of muscle biophysics come to the forefront, including unanticipated interactions between the muscle and its time-varying load, as well as the ability of the muscle cell to adapt rapidly to changes in its dynamic microenvironment. These newly discovered phenomena have been described empirically, but a mechanistic basis to explain them is only beginning to emerge

Airway obstruction in asthma: does the response to a deep inspiration matter?

Airway hyperresponsiveness in asthma may not be a problem of too much airway smooth muscle strength. Rather, it may be a problem of too little of the factors that oppose muscle shortening. The weight of available evidence seems to support the idea that loss of the dilating response to a deep inspiration may play a central role in this process, and that the locus of the response is within the airway smooth muscle cell. Bridge dynamics and plastic reorganization of the smooth muscle cytoskeleton are the focus of this commentary; how these factors interact and details about underlying mechanisms remain unclear

PIV-Based Examination of Deep Stall on an Oscillating Air foil

A number of studies suggest that the deep stall flow fields produced by a pure-pitch and a pure-plunge oscillating airfoil are equivalent, when effective angles of attack are matched. This assumption is examined using particle image velocimetry (PIV). Sinusoidal oscillations of a pure-plunge and pure-pitch airfoil with matched reduced frequency k = 3.93 and with kinematically equivalent amplitudes of effective angle of attack are comparatively examined using results of PIV in a free surface water tunnel at AFRL/RB, Wright Patterson AFB. Experiments were conducted at Re = 10,000 and Re = 40,000, based on free stream velocity and airfoil chord, in order to observe the legitimacy of assuming Reynolds number insensitivity on the respective flow fields. Comparisons are made to computational flow field results collected in a separate, but coordinated, CFD effort. Results for both the pure-plunge case and the pure-pitch case confirm the Reynolds number insensitivity for the high frequency motions researched here. The resulting flow fields for pure-plunge case and the pure-pitch case were vastly different. Experimental results for the pure-plunge case closely resembled those achieved by computation. However, the pure-pitch case experimental and computation results were dissimilar even after considering possible wall effects of the water tunnel. The flow field disagreement between the two motions is not surprising considering trailing edge kinematic dissimilarities

Organizational transformation: Handling the double-edged sword of urgency

A central idea in organizational research and practice is that change efforts demand a sense of urgency. It is also commonly accepted that renewal beyond incremental improvements demand individuals and teams to have what earlier research has called a “promotion focus”—to think innovatively, see opportunities, and think long term. Urgency, however, leads to a “prevention focus,” with which teams and their members are more inclined to seek incremental improvements and error reduction. Hence, urgency seems to both support change and prevent it. Earlier research has not established the conditions under which urgency may lead to creative and productive outcomes. This paper aims to do so. In a study of seven change initiatives at a large media company undergoing a serious crisis, we found that urgency cues could be productively handled by managers and project team members when they addressed three core relationships: (a) the success-failure relationship, (b) the safety-accountability relationship, and (c) the operative-strategic relationship. We make three related theoretical propositions regarding the role of urgency in innovation-driven change and transformation

Learning From Collaborative Action Research in Three Organizations: How Purpose Activates Change Agency

Based on a 2-year collaborative study, this paper explores purpose as an enabler for change agency during the integration of new organizational concepts. We followed three organizations that attempted to actively use purpose to motivate and negotiate innovation-based change initiatives in their respective organizations. Data were gathered through a set of interviews and collaborative inquiry workshops, conducted individually with each organization and collectively with all three. Based on the data, the paper systematically analyzes five ways of how purpose may activate change agency. Moreover, the paper suggests that activation of distributed change agency can support the management of contextual ambidexterity. This study also points toward how other organizations can use the acquired knowledge, both from the study and the collaborative inquiry process

Landskapsanalys med GIS och ett skogligt planeringssystem

Skogsvårdsorganisationen startade en rikstäckande utbildningskampanj under 1999 kallad Grönare Skog. En viktig del av kampanjen utgjordes av de demon­ strationsområden som planerades och färdigställdes under våren 1999. För de landskapsavsnitt där demonstrationsområdena förlades krävdes ett fördjupat underlag med avseende både på kulturella och biologiska faktorer. Syftet med examensarbetet var att ta fram planeringsunderlag på landskapsnivå för de aktuella områdena i form av temakartor över t.ex. lövskogsandel och nyckel­ biotoper, att studera den historiska förändringen av lövskogens utbredning samt att genomföra en analys med avseende på skogens ekonomiska nuvärde. studie­ objektet är beläget i östra Göinge kommun i nordöstra Skåne. De delar av området som idag klassificeras som nyckelbiotoper var 1936 till 80% lövskogar och till 20 % blandskogar. Mycket av den tidigare lövskogen har till idag gjorts om till barrskogar och knappt några nya lövskogar har skapats. Att inte ta hänsyn till naturvården ger högst nuvärde. Ä ven tillväxten och avverkningen blir större om man ej tar hänsyn till naturvården.The National Board of Farestry started a nationwide training and information campaign during 1999 called Greener Forests. An important part of the campaign constitutes of the demonstration areas that were planned and finished during the spring of 1999. In those landscape seetians where the demonstration areas were placed a deepening foundation with reference to both cultural and biologkal factors was needed. The purpose of this thesis was to create planning bases at landscape level for the current areas in the shape of theme mapsover e. g. deci­duous tree share and key habitats, to study the historical change of the deciduous forests and finally to carry through an analysis according to the forests economical net present value. The study object is located in eastern Göinge municipality in the north east of Skåne and covers 2314 ha. The key habitats in the area were in 1936 80 % deciduous forests and 20 % mixed forests. Much of the earlier deciduous forests are remade into coniferous forests and hardly any new deciduous forests have been created. Not taking the environ­ment benefit into consideration gives the highest present net value. Also the growth and the felling are larger while not taking the environment benefit into consideration

Turbulent pseudo-sound production in atherosclerotic arteries.

Massachusetts Institute of Technology. Dept. of Mechanical Engineering. Thesis. 1974. Ph.D.Vita.Bibliography: leaves 114-118.Ph.D