Comparison of mesophyll protoplast isolation and transformation between \u3ci\u3ePanicum virgatum\u3c/i\u3e and \u3ci\u3ePanicum hallii\u3c/i\u3e

Protoplasts are appropriate targets for genome editing, DNA functional screens and transgenesis. This project focuses on the comparison of inexpensive mesophyll protoplast isolation via the use of food-grade enzymes and transformation between diploid Panicum hallii Vasey (PAH) and polyploid cellulosic feedstock Panicum virgatum L (switchgrass), a relative of PAH. PAH has great potential as a C4 model species for crop and bioenergy research. Here an inexpensive switchgrass and PAH mesophyll protoplast isolation and transformation system was developed; the first protoplast system for PAH. Using low-cost commercial food-grade enzymes, a cost reduction of ~1000-fold was achieved compared to traditional protoplast isolating enzymes with a cost of $0.003 (USD) per reaction for switchgrass mesophyll protoplasts and$0.0018 (USD) per reaction for switchgrass cell-suspension culture-derived protoplasts. Additionally, PEG-mediated switchgrass mesophyll protoplast transformation was improved to a maximum 30.4 % over the previous transformation efficiency of 9.1 %, achieving higher transformation efficiency with a reduction in DNA quantity. In the first protoplast isolation system for PAH, an average fivefold increase in protoplast yield from PAH leaf tissue over the optimum switchgrass tissue protoplast isolation was shown. PAH yielded an average 7340 ± 1816 viable protoplasts per mg mesophyll tissue and switchgrass yielded 1468 ± 431 viable protoplasts per mg mesophyll tissue with both species having greater than 95 % viable protoplasts. With additional food-grade enzyme concentration optimization, an additional cost decrease to $0.001 (USD) per reaction was shown. PAH mesophyll protoplasts have a diameter from 3.9- 28.1 µm [micrometer], with a mean of 13.5 µm, which are significantly smaller than switchgrass mesophyll protoplasts which range from 6.5- 39.4 µm with a mean of 17.4 µm. Polyethylene glycol (PEG)-mediated transformation of PAH protoplasts revealed an optimum transformation efficiency of 46.7 ± 5.5 % with switchgrass protoplast transformation efficiency of 9.3 ± 1.9 %. The methods in this project provide an essential step toward using P. hallii as a C4 panicoid model species

Neurotrophic effects of growth/differentiation factor 5 in a neuronal cell line

The neurotrophin growth/differentiation factor 5 (GDF5) is studied as a potential therapeutic agent for Parkinson's disease as it is believed to play a role in the development and maintenance of the nigrostriatal system. Progress in understanding the effects of GDF5 on dopaminergic neurones has been hindered by the use of mixed cell populations derived from primary cultures or in vivo experiments, making it difficult to differentiate between direct and indirect effects of GDF5 treatment on neurones. In an attempt to establish an useful model to study the direct neuronal influence of GDF5, we have characterised the effects of GDF5 on a human neuronal cell line, SH-SY5Y. Our results show that GDF5 has the capability to promote neuronal but not dopaminergic differentiation. We also show that it promotes neuronal survival in vitro following a 6-hydroxydopamine insult. Our results show that application of GDF5 to SH-SY5Y cultures induces the SMAD pathway which could potentially be implicated in the intracellular transmission of GDF5 s neurotrophic effects. Overall, our study shows that the SH-SY5Y neuroblastoma cell line provides an excellent neuronal model to study the neurotrophic effects of GDF5

Meeting house : a behavioral approach and architectural model for a neighborhood multi-service centre.

Thesis. 1975. M.Arch.--Massachusetts Institute of Technology. Dept. of Architecture.Bibliography: leaves 166-167.M.Arch

Resolving the morphological and mechanical properties of palm petioles: shape analysis methods for symmetric sections of natural form

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University London.Palms support the largest leaves in the world and have evolved on Earth for over 120 million years. They are often reported to be the only structure left standing post-hurricane. Cross-sectional shapes of cantilevered structures are important design factors affecting torsional and bending performance. Understanding the shape contribution of natural sections such as palm petioles (modified leaf stalks) is more difficult than those for simple 2D shapes because conventional methods of calculating section properties are not well suited to these irregular shapes. The role of internal structure, material properties and external shape of palm petioles in cantilever performance has been investigated and three main contributions to knowledge result from this research. Firstly, 3D mapping, i.e., the size, orientation and position, of vascular bundles in the Trachycarpus fortunei palm petiole reveals the distributions of stress and Young’s modulus values, providing a more detailed understanding of petioles than previous work. Secondly, bulk elastic material properties along the longitudinal axis of the same petiole are then input to a bi-layered model of the same petiole establishing the Young’s modulus of the two layers without mechanically testing them individually and for determining that the outer layer is not lignified. Thirdly, the largest contribution is the introduction of modified shape transformers employing the use of circular envelopes, eliminating error caused by approximating second moment of area with the torsional constant. This leads to a novel Shape Edge Mapping (SEM) technique which deconstructs petiole cross section shape elements and enables the structural contribution of these elements to be calculated, improving the understanding of the petiole section and how it relates to its mechanical function. This thesis makes a valuable addition to the knowledge of palm function and presents novel techniques for non-destructive extraction of natural shape data for abstraction and use in preliminary engineering design

The Diversity of Life by E.O. Wilson

In The Diversity of Life, E. O. Wilson tells a tale about how our earth is on track for another extinction event and humans are at fault. Wilson discusses various topics such as environmental preservation, biodiversity and its importance, and how life has evolved over time. Wilson views biodiversity differently than many as he focuses on all species found in the ecosystem rather than narrowing his focus on one. He mentions how new species can be created by groups evolving and developing new skills or existing in new environments. Species are going extinct and being created constantly; these extinctions don\u27t have to be large; they can exist on small scales yet still cause an impact on the entire ecosystem. Wilson goes on to explain that humans have existed for a small period of time yet we are the number one cause of extinction events within species. Ultimately, humans will be the cause of our own downfall as the environment is a reflection and product of human actions.https://scholarworks.moreheadstate.edu/celebration_posters_2023/1008/thumbnail.jp

Real-Time Optimization of Anti-Reflective Coatings for CIGS Solar Cells

A new method combining in-situ real-time spectroscopic ellipsometry and optical modeling to optimize the thickness of an anti-reflective (AR) coating for Cu(In,Ga)Se2 (CIGS) solar cells is described and applied directly to fabricate devices. The model is based on transfer matrix theory with input from the accurate measurement of complex dielectric function spectra and thickness of each layer in the solar cell by spectroscopic ellipsometry. The AR coating thickness is optimized in real time to optically enhance device performance with varying thickness and properties of the constituent layers. Among the parameters studied, we notably demonstrate how changes in thickness of the CIGS absorber layer, buffer layers, and transparent contact layer of higher performance solar cells affect the optimized AR coating thickness. An increase in the device performance of up to 6% with the optimized AR layer is demonstrated, emphasizing the importance of designing the AR coating based on the properties of the device structure

Characterization and Analysis of Ultrathin CIGS Films and Solar Cells Deposited by 3-Stage Process

In view of the large-scale utilization of Cu(In,Ga)Se2 (CIGS) solar cells for photovoltaic application, it is of interest not only to enhance the conversion efficiency but also to reduce the thickness of the CIGS absorber layer in order to reduce the cost and improve the solar cell manufacturing throughput. In situ and real-time spectroscopic ellipsometry (RTSE) has been used conjointly with ex situ characterizations to understand the properties of ultrathin CIGS films. This enables monitoring the growth process, analyzing the optical properties of the CIGS films during deposition, and extracting composition, film thickness, grain size, and surface roughness which can be corroborated with ex situ measurements. The fabricated devices were characterized using current voltage and quantum efficiency measurements and modeled using a 1-dimensional solar cell device simulator. An analysis of the diode parameters indicates that the efficiency of the thinnest cells was restricted not only by limited light absorption, as expected, but also by a low fill factor and open-circuit voltage, explained by an increased series resistance, reverse saturation current, and diode quality factor, associated with an increased trap density