Estrogen increases synaptic connectivity between single presynaptic inputs and multiple postsynaptic CA1 pyramidal cells: A serial electron-microscopic study

Dendritic spines are sites of the vast majority of excitatory synaptic input to hippocampal CA1 pyramidal cells. Estrogen has been shown to increase the density of dendritic spines on CA1 pyramidal cell dendrites in adult female rats. In parallel with increased spine density, estrogen has been shown also to increase the number of spine synapses formed with multiple synapse boutons (MSBs). These findings suggest that estrogen-induced dendritic spines form synaptic contacts with preexisting presynaptic boutons, transforming some previously single synapse boutons (SSBs) into MSBs. The goal of the current study was to determine whether estrogen-induced MSBs form multiple synapses with the same or different postsynaptic cells. To quantify same-cell vs. different-cell MSBs, we filled individual CA1 pyramidal cells with biocytin and serially reconstructed dendrites and dendritic spines of the labeled cells, as well as presynaptic boutons in synaptic contact with labeled and unlabeled (i.e., different-cell) spines. We found that the overwhelming majority of MSBs in estrogen-treated animals form synapses with more than one postsynaptic cell. Thus, in addition to increasing the density of excitatory synaptic input to individual CA1 pyramidal cells, estrogen also increases the divergence of input from individual presynaptic boutons to multiple postsynaptic CA1 pyramidal cells. These findings suggest the formation of new synaptic connections between previously unconnected hippocampal neurons.

Specialization in pyramidal cell structure in the sensory-motor cortex of the chacma baboon (Papio ursinus) with comparative notes on macaque and vervet monkeys

The systematic study of pyramidal cell structure has revealed new insights into specialization of the phenotype in the primate cerebral cortex. Regional specialization in the neuronal phenotype may influence patterns of connectivity and the computational abilities of the circuits they compose. The comparative study of pyramidal cells in homologous cortical areas is beginning to yield data on the evolution and development of such specialized circuitry in the primate cerebral cortex. Recently, we have focused our efforts on sensory-motor cortex. Based on our intracellular injection methodology, we have demonstrated a progressive increase in the size of, the branching structure in, and the spine density of the basal dendritic trees of pyramidal cells through somatosensory areas 3b, 1, 2, 5, and 7 in the macaque and vervet monkeys. In addition, we have shown that pyramidal cells in premotor area 6 are larger, more branched, and more spinous than those in the primary motor cortex (MI or area 4) in the macaque monkey, vervet monkey, and baboon. Here we expand the basis for comparison by studying the basal dendritic trees of layer III pyramidal cells in these same sensory-motor areas in the chacma baboon. The baboon was selected because it has a larger cerebral cortex than either the macaque or vervet monkeys; motor cortex has expanded disproportionately in these three species; and motor cortex in the baboon reportedly has differentiated to include a new cortical area not present in either the macaque or vervet monkeys. We found, as in monkeys, a progressive increase in the morphological complexity of pyramidal cells through areas 3b, 5, and 7, as well as from area 4 to area 6, suggesting that areal specialization in microcircuitry was likely to be present in a common ancestor of primates. In addition, we found subtle differences in the extent of the interareal differences in pyramidal cell structure between homologous cortical areas in the three species. (c) 2005 Wiley-Liss, Inc.

Enhanced connectivity and QoE through LTE-WiFi interworking in Smart Cities

Mobile communication and networking infrastructures play an important role in the development of smart cities, to support real-time information exchange and management required in modern urbanization. Mobile WiFi devices that help offloading data traffic from the macro-cell base station and serve the end users within a closer range can significantly improve the connectivity of wireless communications between essential components including infrastructural and human devices in a city. However, this offloading function through interworking between LTE and WiFi systems will change the pattern of resource distributions operated by the base station. In this paper, a resource allocation scheme is proposed to ensure stable service coverage and end-user quality of experience (QoE) when offloading takes place in a macro-cell environment. In this scheme, a rate redistribution algorithm is derived to form a parametric scheduler to meet the required levels of efficiency and fairness, guided by a no-reference quality assessment metric. We show that the performance of resource allocation can be regulated by this scheduler without affecting the service coverage offered by the WLAN access point. The performances of different interworking scenarios and macro-cell scheduling policies are also compared.

Development of distributed generation infrastructure for microgrid connectivity to operational power systems

Distributed Generation (DG) from alternate sources and smart grid technologies represent good solutions for the increase in energy demands. Employment of these DG assets requires solutions for the new technical challenges that are accompanied by the integration and interconnection into operational power systems. A DG infrastructure comprised of alternate energy sources in addition to conventional sources, is developed as a test bed. The test bed is operated by synchronizing, wind, photovoltaic, fuel cell, micro generator and energy storage assets, in addition to standard AC generators. Connectivity of these DG assets is tested for viability and for their operational characteristics. The control and communication layers for dynamic operations are developed to improve the connectivity of alternates to the power system. A real time application for the operation of alternate sources in microgrids is developed. Multi agent approach is utilized to improve stability and sequences of actions for black start are implemented. Experiments for control and stability issues related to dynamic operation under load conditions have been conducted and verified.

Connectivity Mapping (ssCMap) To Predict A20 Inducing Drugs: Anti-inflammatory Action In Cystic Fibrosis

Cystic Fibrosis (CF) lung disease is characterised by a chronic and exaggerated inflammation in the airways. Despite recent developments to therapeutically overcome the underlying functional defect in CFTR (cystic fibrosis transmembrane conductance regulator), there is still an unmet need to also normalise the inflammatory response. The prolonged and heightened inflammatory response in CF is in part mediated by a lack of intrinsic downregulation of the pro-inflammatory NF-kB pathway. We have previously identified reduced expression of the NF-kB down-regulator A20 in CF as a key target to normalise the inflammatory response. Here we have used publically available gene array expression data together with sscMap (statistically significant connections’map)to successfully predict drugs already licensed for the use in humans to induce A20 mRNA and protein expression and thereby reduce inflammation. The effect of the predicted drugs on A20 and NFkB (p65) expression (mRNA) as well as pro-inflammatory cytokine release (IL-8) in the presence and absence of bacterial LPS was shown in bronchial epithelial cells lines (16HBE14o-, CFBE41o-) and in primary nasal epithelial cells (PNECs) from patients with CF (Phe508del homozygous) and non-CF controls. Additionally, the specificity of the drug action on A20 was confirmed using cell lines with TNFAIP3 (A20) knockdown (siRNA). We also show that the A20 inducing effect of ikarugamycin and quercetin is lower in CF derived airway epithelial cells than in non-CF cells.

Effective Cell-Centred Time-Domain Maxwell's Equations Numerical Solvers

This research work analyses techniques for implementing a cell-centred finite-volume time-domain (ccFV-TD) computational methodology for the purpose of studying microwave heating. Various state-of-the-art spatial and temporal discretisation methods employed to solve Maxwell's equations on multidimensional structured grid networks are investigated, and the dispersive and dissipative errors inherent in those techniques examined. Both staggered and unstaggered grid approaches are considered. Upwind schemes using a Riemann solver and intensity vector splitting are studied and evaluated. Staggered and unstaggered Leapfrog and Runge-Kutta time integration methods are analysed in terms of phase and amplitude error to identify which method is the most accurate and efficient for simulating microwave heating processes. The implementation and migration of typical electromagnetic boundary conditions. from staggered in space to cell-centred approaches also is deliberated. In particular, an existing perfectly matched layer absorbing boundary methodology is adapted to formulate a new cell-centred boundary implementation for the ccFV-TD solvers. Finally for microwave heating purposes, a comparison of analytical and numerical results for standard case studies in rectangular waveguides allows the accuracy of the developed methods to be assessed.

Combining ganglion cell topology and data of patients with glaucoma to determine a structure-function map

PURPOSE: To introduce techniques for deriving a map that relates visual field locations to optic nerve head (ONH) sectors and to use the techniques to derive a map relating Medmont perimetric data to data from the Heidelberg Retinal Tomograph. METHODS: Spearman correlation coefficients were calculated relating each visual field location (Medmont M700) to rim area and volume measures for 10 degrees ONH sectors (HRT III software) for 57 participants: 34 with glaucoma, 18 with suspected glaucoma, and 5 with ocular hypertension. Correlations were constrained to be anatomically plausible with a computational model of the axon growth of retinal ganglion cells (Algorithm GROW). GROW generated a map relating field locations to sectors of the ONH. The sector with the maximum statistically significant (P < 0.05) correlation coefficient within 40 degrees of the angle predicted by GROW for each location was computed. Before correlation, both functional and structural data were normalized by either normative data or the fellow eye in each participant. RESULTS: The model of axon growth produced a 24-2 map that is qualitatively similar to existing maps derived from empiric data. When GROW was used in conjunction with normative data, 31% of field locations exhibited a statistically significant relationship. This significance increased to 67% (z-test, z = 4.84; P < 0.001) when both field and rim area data were normalized with the fellow eye. CONCLUSIONS: A computational model of axon growth and normalizing data by the fellow eye can assist in constructing an anatomically plausible map connecting visual field data and sectoral ONH data.

Regulation of human stem cell research in Australia

Australia is currently well placed to contribute to the global growth of human stem cell research. However, as the science has progressed, authorities have had to deal with the ongoing challenges of regulating such a fast moving field of scientific endeavour. Australia’s past and current approach to regulating the use of embryos in human embryonic stem cell research provides an insight into how Australia may continue to adapt to future regulatory challenges presented by human stem cell research. In the broader context, a number of issues have been identified that may impact upon the success of future human stem cell research in Australia.