628 research outputs found
Polymer globule as a nanoreactor
Peculiarities of chemical reactions inside polymer globules with sizes falling in the nanometric range have been theoretically studied. The simplest example of a polymer-catalyzed bimolecular reaction between two low-molecular-weight compounds has been considered to illustrate the advantages of conducting chemical transformations in globular solution of macromolecules. Under theoretical examination of polymer-analogous transformations of polymer molecules, the possibility has been shown of reaction-induced conformational transitions between their coil and globular states. Besides, a pronounced effect has been revealed of the preferential sorption of low-molecular-weight reagents on composition of copolymers formed
The Influence of Self-efficacy and Goal Orientation on Learning Behavior: The Intervening Role of Feedback
Geitz, G., Joosten-ten Brinke, D., & Kirschner, P. (2013). The Influence of Self-efficacy and Goal Orientation on Learning Behavior: The Intervening Role of Feedback. Paper bij de masterclass ‘Hoe balanceer je formatief en summatief toetsen?’ [How to balance formative and summative assessment?], Heerlen, The Netherlands.In this study, the relationship between self-efficacy, goal orientation and feedback is examined to influence the learning behavior corresponding to the state of self-efficacy and the adopted goal orientation. The ultimate aim is to influence learning behavior in order to increase learning outcomes
Nonlinear elasticity and friction of liquid-crystalline polymer monolayers
In the present paper we consider nonlinear elasticity and friction of grafted persistent chains, which are highly stretched in the normal to the surface direction due to orientational interactions. We examine the normal and the lateral forces both in equilibrium and under shear sliding when the monolayer is confined by a bare surface. We show that in the confined monolayer in equilibrium the tilted orientation of the director becomes stable. In the sliding regime the friction force passes through a maximum value. The additional normal force in the sliding regime, when the distance between the surfaces is fixed, is also considered. We show that this force is attractive for small velocities and becomes repulsive for high velocities after the friction force passes through the maximum value
Phase behavior and structure formation of hairy-rod supramolecules
Phase behavior and microstructure formation of rod and coil molecules, which can associate to form hairy-rod polymeric supramolecules, are addressed theoretically. Association induces considerable compatibility enhancement between the rod and coil molecules and various microscopically ordered structures can appear in the compatibility region. The equilibria between microphase-separated states, the coil-rich isotropic liquid and the rod-rich nematic are discussed in detail. In the regime where hairy-rod supramolecules with a high grafting density appear as a result of the association, three phase diagram types are possible depending on the value of the association energy. In the low grafting density regime only the lamellar microstructure is proven to be stable
Prediction of response to biological treatment with monoclonal antibodies in severe asthma
In recent years, major developments have occurred in severe asthma management. Different asthma phenotypes and subgroups have been identified and new treatment options have become available. A total of five monoclonal antibodies are currently approved in severe asthma treatment: omalizumab, mepolizumab, reslizumab, benralizumab and dupilumab. These drugs have been shown to reduce exacerbations and to have an oral corticosteroid-sparing effect in many severe asthma patients. However, biological treatment is not successful in all patients and should be discontinued in non-responsive patients. Treating the right patient with the right biologic, and therefore biologic response prediction, has become a major point of interest in severe asthma management. A variety of response outcomes is utilized in the different clinical trials, as well as a huge range of potential predicting factors. Also, regarding the timing of the response evaluation, there are considerable differences between studies. This review summarizes the results from studies on predicting responses and responders to biological treatment in severe asthma, taking into account clinical, functional and inflammatory parameters assessed prior to the start of treatment as well as following a few months of therapy. In addition, future perspectives are discussed, highlighting the need for more research to improve patient identification and treatment responses in the field of biological treatment in severe asthma
Entangling photons via the double quantum Zeno effect
We propose a scheme for entangling two photons via the quantum Zeno effect,
which describes the inhibition of quantum evolution by frequent measurements
and is based on the difference between summing amplitudes and probabilities.
For a given error probability , our scheme requires that the
one-photon loss rate and the two-photon absorption rate
in some medium satisfy , which is significantly improved in comparison to previous
approaches. Again based on the quantum Zeno effect, as well as coherent
excitations, we present a possibility to fulfill this requirement in an
otherwise linear optics set-up.Comment: 4 pages RevTeX, 2 figure
Chain elongation suppression of cyclic block copolymers in lamellar microphase-separated bulk
Chain elongation suppression of cyclic block copolymers in microphase-separated bulk was determined quantitatively. Solvent-cast and annealed films are confirmed to show alternating lamellar structure and their microdomain spacing D increases with increasing total molecular weight M according to the relationship Dproportional toM(0.59), which agrees quite consistently with the theoretically predicted power law, i.e., Dproportional toM(3/5). This result is in contrast to the well-established issue for linear block copolymers, where the relationship Dproportional toM(2/3) has been confirmed to hold both experimentally and theoretically. This means that chain elongation of each component block is suppressed considerably, owing to their looped conformation in strongly segregated bulk. (C) 2004 American Institute of Physics.</p
Muscle Function in Moderate to Severe Asthma:Association With Clinical Outcomes and Inflammatory Markers
BackgroundPatients with severe asthma have been shown to have low muscle mass, but the clinical consequences are unknown.ObjectiveIn a clinical cohort of patients with moderate to severe asthma, we aimed to assess muscle mass and strength and their relation with functional and clinical outcomes, as well as with systemic inflammatory markers.MethodsMuscle mass and strength were assessed by the fat-free mass index (FFMI), creatinine excretion in a 24-hour urine sample, and handgrip strength test. Functional outcomes included pulmonary function tests and the 6-minute walking distance, whereas clinical outcomes were assessed with questionnaires on asthma control, quality of life, and health care use. Associations of muscle mass and strength with asthma outcomes were assessed with multivariable regression analyses.ResultsA total of 114 patients participated (36% male; mean age, 51.9 ± 14.4 years; body mass index, 27.7 ± 5.7 kg/m2). According to predefined criteria, 16% had a low FFMI and 8% a low urinary creatinine excretion, which did not differ between categories of asthma severity. Both lower FFMI and urinary creatinine excretion were associated with lower values of FEV1 and 6-minute walking distance, whereas a lower handgrip strength was related to worse asthma control, poorer quality of life, and a higher probability of emergency visits (all P < .05). Except for higher leukocytes in relation to lower FFMI, we did not find associations between systemic inflammatory markers and muscle function.ConclusionsThis study demonstrates that low muscle mass is prevalent in patients with moderate to severe asthma and, along with low muscle strength, is associated with poorer clinical and functional outcomes. Our results encourage longitudinal studies into muscle function as a potential target for treatment to improve asthma outcomes
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