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West Jerusalem, Israel

Mercado J.,University of Washington | Gordon-Shaag A.,Hadassah College | Zagotta W.N.,University of Washington | Zagotta W.N.,Howard Hughes Medical Institute | Gordon S.E.,University of Washington
Journal of Neuroscience

TRPV2 is a member of the transient receptor potential family of ion channels involved in chemical and thermal pain transduction. Unlike the related TRPV1 channel, TRPV2 does not appear to bind either calmodulin or ATP in its N-terminal ankyrin repeat domain. In addition, it does not contain a calmodulin-binding site in the distal C-terminal region, as has been proposed for TRPV1. We have found that TRPV2 channels transiently expressed in F-11 cells undergo Ca2+-dependent desensitization, similar to the other TRPVs, suggesting that the mechanism of desensitization may be conserved in the subfamily of TRPV channels. TRPV2 desensitization was not altered in whole-cell recordings in the presence of calmodulin inhibitors or on coexpression of mutant calmodulin but was sensitive to changes in membrane phosphatidylinositol 4,5-bisphosphate (PIP2), suggesting a role of membrane PIP 2 in TRPV2 desensitization. Simultaneous confocal imaging and electrophysiological recording of cells expressing TRPV2 and a fluorescent PIP2-binding probe demonstrated that TRPV2 desensitization was concomitant with depletion of PIP2. We conclude that the decrease in PIP2 levels on channel activation underlies a major component of Ca 2+-dependent desensitization of TRPV2 and may play a similar role in other TRP channels. Copyright©2010 the authors. Source

Israel's population is ageing alongside the worldwide ageing population. As the population ages and the number of older people who are 'ageing in place' increases, the system of elderly care will face new opportunities and challenges in responding to noninstitutional services for elderly care. There is an increasing demand for foreign caregivers despite differences in language and cultural background. This case report describes the global care services provided in Israel by caregivers from the Philippines to emphasis the cultural and social components of elderly care. The following case analyses the use of somatic care practices as culturally intuitive sensitivity practices adjustable to the local culture, especially since the caregiver from the Philippines and her Israeli patient do not share a common language or cultural background. Source

Ben-Knaz R.,Hebrew University of Jerusalem | Pedahzur R.,Hadassah College | Avnir D.,Hebrew University of Jerusalem
RSC Advances

The entrapment of chlorhexidine (CH) within metallic silver (CH@Ag) results in a composite material bearing powerful synergetic bactericidal action towards two opportunistic wound pathogenic bacteria, the Gram-negative Pseudomonas aeruginosa and the Gram-positive Staphylococcus epidermidis. TEM and STEM imaging revealed morphological abnormalities in bacteria exposed to the composite. Release profiles of the active ingredients, CH and ionic silver, from the composite were evaluated by UV spectroscopy and by ICP-MS elemental analysis, and indicated that the strong bactericidal effects were associated with their co-release and presence in the solution. The use of both powder form and pressed form of CH@Ag provides means to control the release kinetics of entrapped CH from the composite and demonstrates the potential application of such composites in wound treatments. © 2013 The Royal Society of Chemistry. Source

Ben-Knaz R.,Hebrew University of Jerusalem | Pedahzur R.,Hadassah College | Avnir D.,Hebrew University of Jerusalem
Advanced Functional Materials

A new concept in bactericidal agents is described: the entrapment of an organic biocidal agent within a bactericidal metal, which leads to synergism between the two components. Specifically this concept is demonstrated for the entrapment of Chlorhexidine digluconate (CHD) within an aggregated silver matrix, a metal known for its own biocidal qualities, forming the CHD@silver composite. The bactericidal efficacy against E. coli is evaluated and compared with the separate components. While the bactericidal efficacy of the individual ingredients (CHD and metallic silver) is very low, CHD@silver exhibits a markedly enhanced efficacy. This enhanced bactericidal effect is partially attributed to the simultaneous release and presence of the active biocidal ingredients CHD and Ag+ in the solution. Detailed composite characterization is provided. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Land M.,Hadassah College
Journal of Physics: Conference Series

We study the quantum mechanical harmonic oscillator in two and three dimensions, with particular attention to the solutions as basis states for representing their respective symmetry groups - O(2), O(1,1), O(3), and O(2,1). The goal of this study is to establish a correspondence between Hilbert space descriptions found by solving the Schrodinger equation in polar coordinates, and Fock space descriptions constructed by expressing the symmetry operators in terms of creation/annihilation operators. We obtain wavefunctions characterized by a principal quantum number, the group Casimir eigenvalue, and one group generator whose eigenvalue is m + s, for integer m and real constant parameter s. For the three groups that contain O(2), the solutions split into two inequivalent representations, one associated with s 0, from which we recover the familiar description of the oscillator as a product of one-dimensional solutions, and the other with s > 0 (in three dimensions, solutions are found for s 0 and s 1/2) whose solutions are non-separable in Cartesian coordinates, and are hence overlooked by the standard Fock space approach. The O(1,1) solutions are singlet states, restricted to zero eigenvalue of the symmetry operator, which represents the boost, not angular momentum. For O(2), a single set of creation and annihilation operators forms a ladder representation for the allowed oscillator states for any s, and the degeneracy of energy states is always finite. However, in three dimensions, the integer and half-integer eigenstates are qualitatively different: the former can be expressed as finite dimensional irreducible tensors under O(3) or O(2,1) while the latter exhibit infinite degeneracy. Creation operators that produce the allowed integer states by acting on the non-degenerate ground state are constructed as irreducible tensor products of the fundamental vector representation. However, the half-integer eigenstates are infinite-dimensional, as expected for the non-compact O(2,1), and no Fock space description is found for this case. For all s ≠ 0 solutions, the SU(N) symmetry of the harmonic oscillator Hamiltonian recently discovered by Bars is spontaneously broken by the ground state. The connection of this symmetry breaking to the non-separability into one-dimensional Cartesian solutions is demonstrated. We conclude with a discussion of the O(2,1) solutions, and the problem of timelike ghost excitations. © Published under licence by IOP Publishing Ltd. Source

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