Cell-mediated gene therapy is one of the new modalities branching out from the wide-ranging field of gene transfer and therapy. When applied to bone formation and regeneration, it has particular advantages depending on the type of cell used as a platform for gene delivery. When utilizing adult mesenchymal stem cells or osteoprogenitor cells for the expression of bone-promoting osteogenic factors, the cells not only express the factors promoting bone growth, but can respond, differentiate and participate in the bone formation process. The ability of engineered cells to respond to the transgene, as well as to other local signals in vivo, confers on them special properties that enable the formation and regeneration of large-scale bone tissue. This approach is a paradigm for the development of gene therapy strategies for other skeletal tissues. Here, we review the most recent studies related to cell-mediated gene therapy for bone formation and regeneration.
EEB Campbell, AV Glotov, A Lassesson, and RD LEVINE. 2002. “Cluster-cluster fusion.” COMPTES RENDUS PHYSIQUE, 3, Pp. 341-352. Abstract
An experimental study of molecular fusion in fullerene-fullerene collisions is presented and the theoretical interpretation of the cross section is reconsidered in terms of phase space arguments and competition with direct collision induced dissociation. The form and absolute magnitude of the cross sections for C60+ + C-70 (or C-70(+) + C-60) and C-70(+) + C-70 can be understood, however, the much smaller cross section for C-60(+)+ C-60 remains a puzzle. The fragmentation behaviour of the hot fusion product is well described by a maximal entropy model indicating equipartition of the centre of mass collision energy followed by statistical fragmentation. (C) 2002 Academie des sciences/Editions scientifiques et medicales Elsevier SAS.
The temperature dependence of the coherent DC conductivity of an Ag quantum dot (QD) monolayer has been computed allowing for size fluctuations of the QDs as well as for packing disorder. The computation uses a scattering formalism with an electron exchange coupling for adjacent QDs. The strength of this coupling can be tuned by compression of the array, and the same coupling is used as previously deter-mined from second harmonic generation spectroscopy of such monolayers. To agree with the experimental results, the computations center attention on the regime of not fully compressed arrays, when the exchange coupling does not fully mask the role of disorder. At very low disorder and/or at higher compressions. the computations show a phase transition to a fully delocalized conducting regime. At very low temperatures, the computed conductivity increases with temperature as exp(-2(E-0/kT)(1/2)). The characteristic energy Eo is found to be a measure of the effective coupling of next-nearest neighbors, suggesting that conduction occurs by variable range charge hopping or, in the language of electron transfer, by super-exchange, At higher temperatures, there is a crossover to an activated regime, exp(-(E-a/kT)), where the activation energy E. is shown to be a measure of the mean excess energy of the moving charges. The transition temperature to activated conduction scales with the extent of disorder. The increase of conductivity with temperature is interpreted as reflecting a gap in the density of conducting states for energies just above the ground electronic state of the array.
Presents information on the consensus development symposium convened by the Bone Club of the European Society for Pediatric Endocrinology on July 6, 2001 concerning the supplementation of vitamin D. Background on vitamin D; Overview of vitamin D deficiency rickets; Risk of children of immigrants for rickets.
Economic impact studies based on short-run spending injections and multipliers lack conceptual ties to measures of economic surplus, fail to capture intangible benefits and generally fail to measure costs. In this case study of the Eurovision Song Contest (ESC) held in Israel in 1999, national benefits from the government-financed televising of the ESC are measured as producer surplus (approximated by private sector incremental profits), consumer surplus (measured as the incremental willingness to pay for an event staged at home) and government surplus (linked to national implicit benefits in the form of promotional advertising cost savings). The opportunity costs of diverting resources to this particular televised event are expressly included as an offset to these gross surplus benefits. Despite the conservative approach, the results show moderate social justification for public support of this high profile televised spectacle and suggest that a cost-benefit approach to cultural events can have wider applications.
Computational results for the temperature-dependent conductivity of compressed arrays of size-selected Ag nanodots are discussed. Special attention is given to the role of phase transitions of the array as a function of external control variables: the applied voltage, the temperature, and the compression of the array. The computations are based on a scattering formalism that is presented in detail so that all the assumptions are explicitly spelled out. The results demonstrate the ability of low-lying excited electronic states of 2D lattices to probe by temperature-dependent conductivity measurements.
This is beyond doubt the finest Coptic grammar ever written, a splendid achievement, masterfully carrying out the formidable task of making the leap from Stern’s pre-scientific (if insightful) Koptische Grammatik of 1880, to bridge a century of Coptic and Egyptian linguistic study. By painstaking and elegant grammatical charting, the Sahidic dialect of Coptic now has a definitive, authoritative description, which I daresay will be superseded only if the corpus changes considerably. The work consolidates the findings of almost a century of research work on Coptic grammar, adding numerous new insights in statements that result from a correct and penetrating analysis of complicated data. It opens much new ground, while providing a clear, even-handed and lucid account of established comprehension, and puts much in a fresh perspective, often contradicting orthodoxy and deepening or clarifying the insights offered in many a study.
A new algorithm for computing anharmonic vibrational states for polyatomic molecules is proposed. The algorithm starts with the vibrational self-consistent field (VSCF) method and uses degenerate perturbation theory to correct for effects of correlation between different vibrational modes. The algorithm is developed in a version that computes the anharmonic vibrational spectroscopy directly from potential energy surface points calculated by using ab initio codes. The method is applied to several molecules where near degeneracies occur for excited vibrational states, including HOOH, HSSH, and HOOOH. The method yields results in very good accordance with experiments and generally provides improvements over nondegenerate perturbation corrections for VSCF. (C) 2002 American Institute of Physics.
This article examines the relationship between demonic possession and female spirituality in convents during late medieval and early modern Europe. The author argues the misdiagnosis of possession was acutally a result of psychological and spiritual tensions due to contradictory expectations of the nuns.
We find that the anomalous behavior of optical spatial screening solitons observed in the high-symmetry paraelectric phase is a consequence of nonlinear dielectric effects. These, coupled to space charge in saturated conditions, change the effective optical nonlinearity even far from the phase-transition regime.
This paper looks at the impact of high technology employment concentrations on urban sprawl. A methodology for translating spatial employment patterns, into place of residence patterns, is presented. On this basis, the consumption of land at the urban fringe due to both residential and non-residential uses, is estimated. The method is tested empirically using data relating to the two main outer suburban agglomerations of high technology activity in the Chicago metropolitan area. Two counter-factual situations are simulated. The first relates to a spatial counter-factual whereby the high tech concentrations develop in the city of Chicago or within the inner suburbs. The second presents an industry counter-factual that estimates the land consumption impacts arising from the development of an alternative industrial concentration in the same location. The results of the actual and hypothetical cases are compared. They point to a considerable saving in acreage in all alternative scenarios. Some policy implications are highlighted.
This essay argues that by structuring specific patterns of response, a work of literature (Hamlet) can create an awareness that cannot be achieved through systematic philosophical presentation. The play's extensive [...]
Molecular-dynamics simulations of a cluster impacting a hard surface show that, initially, the cluster is rapidly compressed and translationally heated. During this short but distinct stage, the cluster is a suitable medium for chemistry: the number of layers of the cluster is not changing; the constituents of the cluster can collide several times and both bimolecular and collisionally driven unimolecular reactions can occur. Hypersonic velocities of impact are needed for a considerable temperature rise. Following compression, the cluster fragments by expanding into a hemispheroidal plume. For supersonic impact. the cluster expands nearer to the surface forming an oblate, omelet-like, hemispheroid. (C) 2002 Elsevier Science B.V. All rights reserved.
