Polymer physics inspired approaches for the study of the mechanical properties of amyloid fibrils

Amyloid structures constitute a class of highly ordered nanomaterials formed by insoluble protein aggregates. These aggregates are characterized by a cross‐β structural motif in which β‐sheets are oriented perpendicular to the fibril axis and bound together by a dense hydrogen bonding network. Although they have been associated with several neurodegenerative disorders, such as Alzheimer's and Parkinson's diseases, amyloid fibrils have also been found in many physiologically beneficial roles, for instance in adhesives and hormone storage. Inspired by this natural occurrence of functional amyloid, the hierarchal self‐assembly of these structures has recently been used to develop artificial biomaterials for applications in medicine and nanotechnology. In order to realize the full potential of amyloids as functional materials, it is important to understand their fundamental mechanical properties. This review explores a range of experimental strategies to determine the mechanical properties of amyloid fibrils and discusses the results in the context of polymer physics concepts. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014 , 52, 281–292     

A conjecture by G. Ladas

In this paper, a sufficient condition for boundedness and persistence of the solu1 /of the following delay difference equation is obtained. A conjecture by G. Ladas is proved here xn-1=A/x^pn B/x^qn-1, n=0,1,...where A, B, p, q, x-1, xo∈(0,∞).     

On classes of analytic functions related to conic domains

We introduce classes of analytic functions related to conic domains, using a new linear multiplier fractional differential operator (n∈N₀={0,1,…}, 0?α<1, λ?0), which is defined as

D⁰f(z)=f(z),     

MODELING THE EFFECTS OF WOOD AND NON‐WOOD BASED INDUSTRIES ON FORESTRY RESOURCES

Pollution due to the wood and non‐wood based industries is one of the main reasons for the depletion of forestry resources. On the onset of industrial era, the number of industries was less but now it has increased much due to rapid pace of development. Industrialization affects forestry resources in two ways: (i) using raw materials by wood based industries and cut down by non‐wood based industries and (ii) emitting pollutants by wood and non‐wood based industries. In view of this, in this paper, we have proposed and analyzed a mathematical model to assess the effects of wood and non‐wood based industries on the depletion of forestry resources. In the modeling process, it is assumed that wood and non‐wood based industries deplete the forestry resources directly, whereas pollutants emitted by both types of industries decrease the growth rate of forestry resources indirectly. The equilibria are obtained and their stability is discussed. The model analysis reveals that forestry resources decrease due to the growth in wood based industries but the overgrowth in non‐wood based industries and pollutants emitted by them in the environment adversely affect the forestry resources. Numerical simulation is provided to support analytical findings.     

Approximation of common fixed points for finite families of nonself asymptotically nonexpansive mappings in Banach spaces

Let E be a real uniformly convex Banach space, K be a closed convex nonempty subset of E which is also a nonexpansive retract with retraction P. Let be asymptotically nonexpansive mappings of K into E with sequences (respectively) satisfying kin→1 as n→∞, i=1,2,…,m, and . Let be a sequence in [?,1−?],?∈(0,1), for each i∈{1,2,…,m} (respectively). Let {xn} be a sequence generated for m?2 by

     

中立型时变非线性控制系统的镇定与控制

本文利用［１－ ３］中的方法,讨论了一类具有滞后的中立型时变非线性控制系统（在闭环情况下）的镇定与次优控制问题．得到了滞后量与非线性项的估计范围．     

PERSISTENCE OF POPULATIONS FOR A PREDATOR-PREY SYSTEM IN A POLLUTED ENVIRONMENT

1IntroductionTheinfluenceoftoxicantsonthepersistenceandextinctionofpopulationsinapollutedenvironmentisveryimportant.In1983,T.C.Hallametal.firstproposedadeterministicmodeltostudythetoxiceffectsonpopulationgrowth[fi.In1986,T.G.HallamandZ.Maproposedtheconceptofpersistenceinthemeanofpopulations[2],anewmethodtodeterminethethresholdsbetweenpersistenceandextinctionofpopulationsofnonautonomousmodelshasbeenprovidedintheirpaper.Thethresholdsbetweenpersistenceandextinctionforsomemodelshavebeenobtaine…     

具有时滞食物链系统周期解的存在性和全局渐近稳定性

本文考虑时滞三种群食物链系统,给出周期解存在和全局渐近的充分条件。     

Some Results on Sinai Diffusion

The diffusion of a particle in a one-dimensional random force field (Sinai diffusion) is studied using the replica method. This method, which maps the problem onto a quantum problem, is shown to be a simple and direct way to calculate the long-time diffusive behavior. Results for the distribution of the local Green's function, the particle distribution, and persistence are obtained.