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Full-Text Articles in Physical Sciences and Mathematics

Detectability Of Excitatory Versus Inhibitory Drive In An Integrate-And-Fire-Or-Burst Thalamocortical Relay Neuron Model, Gregory D. Smith, S. M. Sherman Dec 2002

Detectability Of Excitatory Versus Inhibitory Drive In An Integrate-And-Fire-Or-Burst Thalamocortical Relay Neuron Model, Gregory D. Smith, S. M. Sherman

Arts & Sciences Articles

Although inhibitory inputs are often viewed as equal but opposite to excitatory inputs, excitatory inputs may alter the firing of postsynaptic cells more effectively than inhibitory inputs. This is because spike cancellation produced by an inhibitory input requires coincidence in time, whereas an excitatory input can add spikes with less temporal constraint. To test for such potential differences, especially in the context of the function of thalamocortical (TC) relay nuclei, we used a stochastic “integrate-and-fire-or-burst” TC neuron model to quantify the detectability of excitatory and inhibitory drive in the presence and absence of the low-threshold Ca 2+ current, IT, and …


Synthesis And Characterization Of Hydroxyapatite-Collagen Biocomposite Materials, Vuk Uskoković, Nenad Ignjatović, Nadejda Petranović Sep 2002

Synthesis And Characterization Of Hydroxyapatite-Collagen Biocomposite Materials, Vuk Uskoković, Nenad Ignjatović, Nadejda Petranović

Pharmacy Faculty Articles and Research

Hydroxyapatite-collagen composite is a prosperous biomaterial in reconstructive surgery for the reparation of defects within human hard tissue. Within this research, three-dimensional blocks of HAp/collagen composite biomaterial were synthesized by homogenizing the HAp/collagen mixture by cold and hot (T=60oC) pressing (P=49 MPa). The changes in the system were followed by using thermal analysis (DSC & TGA), FT-IR spectroscopy and scanning electron microscopy (SEM). The identification and kinetic analysis of appearing phase transition were done. FT-IR spectrum of the biocomposite shows that neither cold nor hot pressing had significant influence on the individual components of the composite. SEM of the fracture …


Actiononaias Ligamentina As A Biomonitor In The Green River: An Unique Approach For Analysis Of Environmental Impacts, Robert Kirkland Jan 2002

Actiononaias Ligamentina As A Biomonitor In The Green River: An Unique Approach For Analysis Of Environmental Impacts, Robert Kirkland

Masters Theses & Specialist Projects

Biomonitoring has become an important component in bioassessment programs. It is used to maintain high water quality standards, and determine contaminant levels and biological affects in areas that have been heavily disturbed. The objectives of this research were 1) to improve and apply certain modern biomonitoring techniques and 2) to locate possible contaminant sources affecting the flora and fauna of the Green River and of Mammoth Cave. Actinonaias ligamentina (Lamarck, 1819), a freshwater mussel, was used for interpretation of these impacts as well as refinement of biomonitoring techniques. The mussels were collected in the Lawler Bend region of the Green …