Neurogenesis from Neural Stem Cells, Ependymal Cells and Fibroblasts

Stroke is a major cause of death and disability around the world. Stroke leads to loss of neurons and also other cells in the brain due to lack of blood supply. Currently no therapies are available to treat stroke-related disability. It has been shown that stroke leads to increased neurogenesis, birth of new neurons, within the brain. This increased neurogenesis is not sufficient to restore lost function. There is a need to develop therapies for neuronal replacement by improving neurogenesis within the brain and / or transplanting neurons. Cortical strokes lead to more disability after stroke as compared to those affecting the striatum, and whether cortical neurogenesis occurs after stroke is controversial. Cell transplantation may be the key to cortical repair after stroke. Reports have identified positive but very few negative regulators of neurogenesis after stroke, and suggested that ependymal cells can also contribute to stroke-induced neurogenesis. Transplantation of neurons generated from different sources such as fetal brain, embryonic stem cells and induced pluripotent stem cells are associated with ethical issues and carry the risk of immune rejection and tumorigenicity. Direct conversion of patient’s own skin cells to neurons could overcome these problems and potentially restore function after transplantation in stroke-damaged brain. In this thesis we have used transgenic models, viral vectors, electroporation-mediated gene delivery and overexpression of transcription factors to demonstrate neurogenesis from neural stem cells, ependymal cells in the lateral ventricular wall and fibroblasts. We show that Lnk, a known inhibitor of hematopoietic stem cell self-renewal, is also expressed in the brain. Overexpression or removal of Lnk expression leads to decreased or increased neurogenesis in vitro respectively. When brain is damaged by stroke there is increased proliferation of neural stem cells in animals without Lnk expression. This was not observed in status epilepticus, a severe form of epilepsy. We determined that upregulation of Stat1/3 after stroke leads to increased Lnk expression. Subsequently Lnk inhibits cellular response to increased IGF1 stimulation after stroke, by decreasing Akt phosphorylation. We have identified Lnk signaling as a novel mechanism of influencing neurogenic response to stroke. We next determined if ependymal cells in lateral ventricular wall of adult rat brain contribute to neurogenesis after stroke. We identified FoxJ1 as a marker of ependymal cells in rats similar to mice, and used FoxJ1 promoter in piggyBac system to genetically label these cells with fluorescent reporter proteins GFP or RFP by electroporation. Tracing the lineage of the labeled cells in intact and stroke-damaged brain, we identified that FoxJ1 expressing cells contribute to olfactory bulb neurogenesis while the striatal neurogenic response was not significant. Thus, FoxJ1 expressing cells probably have only a minor role in repair after stroke. We then tested whether human fetal lung fibroblasts could be directly converted to cortical neurons. We overexpressed sets of transcription factors that are known to be involved in cortical neuron development. We found that overexpression of different sets of these factors in fibroblasts converted them to cortical-like neurons. These neurons expressed markers of cortical neurons and were functional by electrophysiology. In summary, these results raise the possibility that inhibition of Lnk, a negative regulator of neurogenesis from the brain’s own neural stem cells, and intracortical transplantation of cortical neurons directly converted from fibroblasts could be developed into novel therapeutic strategies for stroke in the future

Analysis of GRACE range-rate residuals with focus on KBR instrument system noise

We investigate the post-fit range-rate residuals after the gravity field parameter estimation from the inter-satellite ranging data of the gravity recovery and climate experiment (GRACE) satellite mission. Of particular interest is the high-frequency spectrum (f gt 20 MHz) which is dominated by the microwave ranging system noise. Such analysis is carried out to understand the yet unsolved discrepancy between the predicted baseline errors and the observed ones. The analysis consists of two parts. First, we present the effects in the signal-to-noise ratio (SNRs) of the k-band ranging system. The SNRs are also affected by the moon intrusions into the star cameras field of view and magnetic torque rod currents in addition to the effects presented by Harvey et al. [2016]. Second, we analyze the range-rate residuals to study the effects of the KBR system noise. The range-rate residuals are dominated by the non-stationary errors in the high-frequency observations. These high-frequency errors in the range-rate residuals are found to be dependent on the temperature and effects of sun intrusion into the star cameras field of view reflected in the SNRs of the K-band phase observations

Metasediments of the deep crustal section of Southern Karnataka

A review of the rocks of supracrustal origin in the amphibolite and granulite facies terrane in southern Karnataka was presented. In addition to introducing the metasediments in the field area of the workshop, a review was presented of the common occurrence of metasediments in amphibolite and granulite facies rocks worldwide. Models of granulite metamorphism must include a mechanism for the burial of these sediments to the depths recorded by the geobarometers in granulite metamorphism in addition to their reexposure at the surface. Unfortunately, the common occurrence of supracrustals in granulite facies rocks, sometimes with remarkably little deformation was deemed significant

Genetic Variability in Indian Spinach (Basella alba L.)

Evaluation of eleven germplasm lines of the Indian spinach (basella) revealed maximum leaf weight/plant in IIHR-1 (160.5g), followed by IIHR-18 (111.6g) and IIHR-3 (98.3g). Results of genetic studies revealed that phenotypic coefficient of variation was higher than genotypic coefficient of variation for all the traits studied, indicating environmental influence on expression of these characters. Moderate heritability along with high genetic advance was recorded for leaf weight and total plant weight, indicating the presence of additive gene effects. Hence, selection can be employed for improvement of these characters in basella. Higher plant weight was found to be significantly and positively associated with branch number, leaf number, leaf weight and stem weight. Leaf number had the maximum direct positive effect on total plant weight, followed by leaf length. Indirect effects of other characters through these characters were also seen to be positive. Thus, for yield improvement in basella, emphasis may be laid on indirect selection through leaf characters like leaf number, leaf length and leaf weight

Building Location-based Service with Java Technologies

The growing use of Java in Location-based Service provides an opportunity to find solutions for problems and challenges in the rapidly changing telecommunications environment. This paper describes the development of location-based service components using Java technologies. The technologies include J2ME, Servlet, Java Server Pages (JSP) and XML Java Binding Tool. The developed components are the location server simulator, location service application and device client application. This study is crucial for support of BT’s launch of User Location Service on prototype ERICA mobile application platform through supporting the testing and validation of the platform components

Performance Evaluation of Multi Antenna Techniques in LTE

High data rate requirements of the Long Term Evolution - Advanced (LTE-A) systems can be achieved by adopting advanced Multiple Input Multiple Output (MIMO) antenna techniques on both uplink and downlink. The LTE air-interface supports multiple-antenna transmit arrays and different modes of multiple antenna transmissions. In this paper, performance of different MIMO techniques is evaluated using QualNet network simulator. The MIMO techniques considered for performance evaluation are SingleInput/Multiple-Output (SIMO), Open Loop Spatial Multiplexing (OLSM) and Space-Frequency Block Coding (SFBC). The performance metrics considered are throughput, delay and jitter

Performance Evaluation of Round Robin and Proportional Fair Scheduling Algorithms for Constant Bit Rate Traffic in LTE

Scheduling is a key Radio Resource Management (RRM) mechanism for realizing Quality of Service (QoS) requirements and optimizing system performance of Long Term Evolution (LTE) network. Scheduling is the process of dynamically allocating physical resources to User Equipments (UEs) based on scheduling algorithms implemented at the LTE base station. Various algorithms have been proposed by network designers/researchers as the implementation of scheduling algorithm is an open issue in LTE standard. The choice of scheduling algorithm critically impacts resource utilization and the overall performance of LTE network. This paper makes an attempt to study and compare the performance of Round Robin (RR) and Proportional Fair (PF) scheduling algorithms for Constant Bit Rate (CBR) traffic scenario. Performance metrics considered for simulation studies are throughput, delay and jitter

Performance Study of Round Robin and Proportional Fair Scheduling Algorithms by Emulation for Video Traffic in LTE Networks

Video communication over mobile broadband is gaining popularity due to the increased demand for applications such as Video on Demand (VoD), IPTV, video conferencing etc. In order to support these video applications over mobile broadband, efficient video streaming within the limited bandwidth environment is essential. Further, Long Term Evolution (LTE) network incorporates advanced Radio Resource Management (RRM) mechanism such as scheduling to realize efficient video streaming over limited bandwidth arena. Scheduling does the task of dividing and allocating radio resources in order to maximize system throughput and enhance Quality of Experience (QoE) of the end user. Hence, in this paper an attempt has been made to evaluate the performance of Round Robin (RR) and Proportional Fair (PF) scheduling algorithms using EXata network emulator for real video traffic generated by Video LAN (VLC) media player. Packet Delivery Ratio (PDR) and throughput are considered as performance metrics for the emulation studies

Performance Study of Proportional Fair Scheduling Algorithm with Transmit Diversity Multi-Antenna Technique for Lte Network

Long Term Evolution (LTE) access network is based on Orthogonal Frequency Division Multiple Access (OFDMA) which provides multi user diversity gain to enhance the system throughput. However, fading of a radio channel causes inter channel interference and reduces overall system throughput. This deteriorating effect of wireless channel fading is higher for mobile users which can be reduced by channel aware scheduling algorithm and transmit diversity multi-antenna technique. Hence in this paper, an attempt has been made to evaluate the effect of mobility on the performance of Proportional Fair (PF) channel aware scheduling algorithm in conjunction with transmit diversity multi-antenna technique by considering throughput, delay and jitter as performance metrics.