Let G = (V, E) be an undirected weighted graph on |V | = n vertices and |E| = m edges. For the graph G, A spanner with stretch t ∈ N is a subgraph (V, ES), ES ⊆ E, such that the distance between any pair of vertices in this subgraph is at most t times the distance between them in the graph G. We present simple and efficient dynamic algorithms for maintaining spanners with essentially optimal (e...

Mechanical ventilation can injure the lung, causing edema and alveolar inflammation. Interleukin-8 (IL-8) plays an important role in this inflammatory response. We postulated that cyclic cell stretch upregulates the production and release of IL-8 by human alveolar epithelium in the absence of structural cell damage or paracrine stimulation. To test this hypothesis, alveolar epithelial cells (A5...

Hemodynamic forces are important effectors of endothelial cell phenotype and function. Because CD40-CD154 interactions between endothelial cells and mononuclear leukocytes or activated platelets play an important role in vascular dysfunction, we investigated the effects of cyclic stretch on CD40 expression in human cultured endothelial cells. Short-term stretch transiently up-regulated CD40 exp...

In humans, enhanced joint range of motion is observed after static stretch training and results either from an increased stretch tolerance or from a change in the biomechanical properties of the muscle-tendon unit. We investigated the effects of an intermittent stretch training on muscle biomechanical and structural variables. The left plantarflexors muscles of seven anesthetized New Zealand (N...

We consider the problem of routing in an asynchronous dynamically changing ring of processors using schemes that minimize the storage space for the routing information. In general, applying static techniques to a dynamic network would require significant re-computation. Moreover, the known dynamic techniques applied to the ring lead to inefficient schemes. In this paper we introduce a new techn...

Renal obstruction is frequently found in adults and children. Mechanical stimuli, including pressure and stretch in the obstructed kidney, contribute to damage; animal models of obstruction are characterized by increased cellular proliferation. We were interested in the direct effects of pressure and stretch on renal tubular cell proliferation. Human HKC-8 or rat NRK-52E proximal tubule cells w...

Establishing extracellular milieus to stimulate neuronal regeneration is a critical need in neuronal tissue engineering. Many studies have used a soluble factor (such as nerve growth factor or retinoic acid [RA]), micropatterned substrate, and electrical stimulation to induce enhanced neurogenesis in neuronal precursor cells. However, little attention has been paid to mechanical stimulation bec...

Hemodynamic forces are important effectors of endothelial cell phenotype and function. Because CD40-CD154 interactions between endothelial cells and mononuclear leukocytes or activated platelets play an important role in vascular dysfunction, we investigated the effects of cyclic stretch on CD40 expression in human cultured endothelial cells. Shortterm stretch transiently up-regulated CD40 expr...

Stretch-induced skeletal muscle growth may involve increased autocrine secretion of insulin-like growth factor-1 (IGF-1) since IGF-1 is a potent growth factor for skeletal muscle hypertrophy, and stretch elevates IGF-1 mRNA levels in vivo. In tissue cultures of differentiated avian pectoralis skeletal muscle cells, nanomolar concentrations of exogenous IGF-1 stimulated growth in mechanically st...

The aim of this study was to determine whether Ia and II fiber discharges of soleus muscle spindles were modified after a 14-day period of hypodynamia (absence of weight bearing) and hypokinesia (reduction of motor activity). Fifty-one and 38 afferent fibers were studied, respectively, in control and hypodynamia-hypokinesia (HH) groups. Under deep anesthesia (pentobarbital, 30 mg/kg), a L3-L6 l...