Interactive effects of joint angle, contraction state and method on estimates of Achilles tendon moment arms

The muscle-tendon moment arm is an important input parameter for musculoskeletal models. Moment arms change as a function of joint angle and contraction state and depend on the method being employed. The overall purpose was to gain insights into the interactive effects of joint angle, contraction state and method on the Achilles tendon moment arm using the center of rotation (COR) and the tendon excursion method (TE). Moment arms were obtained at rest (TErest, CORrest) and during a maximum voluntary contraction (CORMVC) at four angles. We found strong correlations between TErest and CORMVC for all angles (0.72 ≤ r ≤ 0.93) with Achilles tendon moment arms using CORMVC being 33 - 36% greater than those obtained from TErest. The relationship between Achilles tendon moment arms and angle was similar across both methods and both levels of muscular contraction. Finally, Achilles tendon moment arms for CORrest were 1 – 8% greater than for CORMVC. [NB rendition of scientific symbols is approximate in this display; please check full text for precise rendition]

A novel stand-alone solar-powered agriculture greenhouse-desalination system; increasing sustainability and efficiency of greenhouses

This is the author accepted manuscript.The countries in the Middle East and North Africa (MENA) region are suffering from the scarcity of freshwater resources. With the economic development and population growth, planning the additional water supplies is critical for this region. Desalination of saline water is, therefore, considered as a strategic alternative water resources and technology to be adopted in MENA region. On the other hand, open field agriculture in such conditions is not economical particularly with high ambient temperature and solar intensity. Agriculture Greenhouses (GH) present a suitable alternative for different plants growth for the region’s desert. In most cases GHs can reduce about 90% of irrigating water demand compared open field. With the available high solar energy, integration of solar – GH – desalination presents a real challenge and is the field of newly funded N-M R&D proposal. This paper presents an integration of solar energy, agriculture GH and suitable desalination processes targeting the development and pilot testing of a novel stand-alone system that grows its energy and irrigation water demand.British CouncilScience & Technology Development Fund (STDF), Egyp

Effect of high temperature VPT conditions on the development of aligned ZnO nanorod arrays grown by a three step catalyst-free method

Using Transmission Electron Microscopy-related techniques, we study the effect of the high temperature in the Vapour Phase Transport (VPT) process on the morphology and chemistry of VPT ZnO nanorod arrays deposited on a two-step Chemical Bath Deposition (CBD) buffer layers on silicon substrates. Though well-aligned and c-axis oriented arrays of ZnO nanorods are achieved, we have noticed the strong dependence of the nanorod morphology on the VPT growth conditions such as the temperature ramp rate and the placement of samples with respect to the metal source. The development of conical structures in the nanorod bases and the formation of a double intermediate layer below the base of nanorods are the main features found. The modifications of the ZnO nanostructures both in the base and in the underlying buffer layers due to the high VPT temperatures are also examined in detail

Solitonic excitations in the Haldane phase of a S=1 chain

We study low-lying excitations in the 1D $S=1$ antiferromagnetic valence-bond-solid (VBS) model. In a numerical calculation on finite systems the lowest excitations are found to form a discrete triplet branch, separated from the higher-lying continuum. The dispersion of these triplet excitations can be satisfactorily reproduced by assuming approximate wave functions. These wave functions are shown to correspond to moving hidden domain walls, i.e. to one-soliton excitations.Comment: RevTex 3.0, 24 pages, 2 figures on request by fax or mai

Universality class of S=1/2 quantum spin ladder system with the four spin exchange

We study s=1/2 Heisenberg spin ladder with the four spin exchange. Combining numerical results with the conformal field theory(CFT), we find a phase transition with central charge c=3/2. Since this system has an SU(2) symmetry, we can conclude that this critical theory is described by k=2 SU(2) Wess-Zumino-Witten model with Z$_2$ symmetry breaking

Study of morphological and chemical changes of aligned zinc oxide nanorods growth by vapour phase transport on chemical bath deposited buffer layers

c-axis aligned ZnO nanorods were deposited by vapour phase transport on textured chemical bath deposited buffer layers. In this work we examine the role of the buffer layer and how it influences the vapour phase transport deposition process using both scanning and scanning transmission electron microscopes and related techniques. Vapour phase transport deposition on chemical bath deposited buffer is a complex growth process with many simultaneously effects including; (i) substantial morphological transformation at high temperature, which influences the base of the nanorods; (ii) the formation of a mixed amorphous / crystalline ZnxSi1-xOy interface during the vapour phase transport growth on silicon substrates; (iii) the overgrowth of the ZnO seed layers, by the silica interface rendering them inactive for nanorod nucleation, suggesting there is a minimum critical thickness ZnO buffer layer necessary for vapour phase transport growth of ZnO nanorods on silicon substrates. We discuss the relative importance of these effects on the overall growth process and use this understanding to explain previous results in the literature

Tropomodulin’s Actin-Binding Abilities Are Required to Modulate Dendrite Development

There are many unanswered questions about the roles of the actin pointed end capping and actin nucleation by tropomodulins (Tmod) in regulating neural morphology. Previous studies indicate that Tmod1 and Tmod2 regulate morphology of the dendritic arbor and spines. Tmod3, which is expressed in the brain, had only a minor influence on morphology. Although these studies established a defined role of Tmod in regulating dendritic and synaptic morphology, the mechanisms by which Tmods exert these effects are unknown. Here, we overexpressed a series of mutated forms of Tmod1 and Tmod2 with disrupted actin-binding sites in hippocampal neurons and found that Tmod1 and Tmod2 require both of their actin-binding sites to regulate dendritic morphology and dendritic spine shape. Proximity ligation assays (PLAs) indicate that these mutations impact the interaction of Tmod1 and Tmod2 with tropomyosins Tpm3.1 and Tpm3.2. This impact on Tmod/Tpm interaction may contribute to the morphological changes observed. Finally, we use molecular dynamics simulations (MDS) to characterize the structural changes, caused by mutations in the C-terminal helix of the leucine-rich repeat (LRR) domain of Tmod1 and Tmod2 alone and when bound onto actin monomers. Our results expand our understanding of how neurons utilize the different Tmod isoforms in development

Pretransplant assessment of human liver grafts by plasma lecithin: cholesterol acyltransferase (LCAT) activity in multiple organ donors.

In spite of the improved outcome of orthotopic liver transplantation (OLTx), primary graft nonfunction remains one of the life-threatening problems following OLTx. The purpose of this study was to evaluate plasma lecithin: cholesterol acyltransferase (LCAT) activity in multiple organ donors as a predictor of liver allograft viability prior to OLTx. Thirty-nine donors were studied during a 5-month period between April and August 1988. Allograft hepatectomy was performed using a rapid technique or its minor modification with hilar dissections, and the allografts were stored cold (4 degrees C) in University of Wisconsin (UW) solution. Early post-transplant allograft function was classified as good, fair, or poor, according to the highest SGOT, SGPT, and prothrombin time within 5 days following OLTx. Procurement records were reviewed to identify donor data, which included conventional liver function tests, duration of hospital stay, history of cardiac arrest, and graft ischemic time. Blood samples from the donors were drawn immediately prior to aortic crossclamp, and from these plasma LCAT activity was determined. Plasma LCAT activity of all donors was significantly lower than that of healthy controls (12.4 +/- 8.0 vs 39.2 +/- 13.3 micrograms/ml per hour, P less than 0.01). LCAT activity (16.4 +/- 8.3 micrograms/ml per hour) in donors of grafts with good function was significantly higher than that in those with fair (8.6 +/- 4.5 micrograms/ml per hour, P less than 0.01) or poor (7.3 +/- 2.4 micrograms/ml per hour, P less than 0.01) function.(ABSTRACT TRUNCATED AT 250 WORDS

Robustness of Cooperation in the Evolutionary Prisoner's Dilemma on Complex Networks

Recent studies on the evolutionary dynamics of the Prisoner's Dilemma game in scale-free networks have demonstrated that the heterogeneity of the network interconnections enhances the evolutionary success of cooperation. In this paper we address the issue of how the characterization of the asymptotic states of the evolutionary dynamics depends on the initial concentration of cooperators. We find that the measure and the connectedness properties of the set of nodes where cooperation reaches fixation is largely independent of initial conditions, in contrast with the behavior of both the set of nodes where defection is fixed, and the fluctuating nodes. We also check for the robustness of these results when varying the degree heterogeneity along a one-parametric family of networks interpolating between the class of Erdos-Renyi graphs and the Barabasi-Albert networks.Comment: 18 pages, 6 figures, revised version accepted for publication in New Journal of Physics (2007