Catalytic constructive deoxygenation of lignin-derived phenols: new C-C bond formation processes from imidazole-sulfonates and ether cleavage reactions

Funding: UK Engineering and Physical Sciences Research Council (EPSRC)As part of a programme aimed at exploiting lignin as a chemical feedstock for less oxygenated fine chemicals, several catalytic C-C bond forming reactions utilising guaiacol imidazole sulfonate are demonstrated. These include the cross-coupling of a Grignard, a non-toxic cyanide source, a benzoxazole, and nitromethane. A modified Meyers reaction is used to accomplish a second constructive deoxygenation on a benzoxazole functionalised anisole.Publisher PDFPeer reviewe

Transcriptional Regulation of Cell-type Specific Expression in the Arabidopsis Root

Characterizing transcription factor interactions with their corresponding binding sites is crucial for understanding how gene expression is regulated by DNA sequence. A more comprehensive understanding of this process could have benefits in synthetic promoter design and creation of genetically modified organisms. Herein, the promoters of genes exhibiting cell-type specific expression within a single layer of the Arabidopsis root are analyzed to identify cis-regulatory motifs implicated in cell-type specific expression. De novo motif prediction identifies multiple motif candidates overly represented in the promoter sequences of co-expressed genes specific for epidermal, cortex, and endodermal expression. Several endodermal specific putative motifs are further analyzed for positional biases and tested in planta. A priori mapping of known cis-regulatory motifs catalogued in publicly available databases is also performed. Results show that cell-types contain different statistically significant enrichment patterns of both predicted and known cis-regulatory motifs. These results will help future research in designing cell-type specific synthetic promoters

Plant improvement for insect resistance: Testing of the candidate organism Beauveria bassiana, transgenic tobacco expressing protease inhibitors, and rapid screen of insect resistance genes in an agroinfiltration transient expression system

This study focused on three aspects of plant improvement for insect resistance including: testing of candidate organisms for their production of insecticidal proteins, testing of transgenic plants expressing insect resistance genes, and testing novel systems for the evaluation of insect resistance genes. In the initial part of this study, the candidate fungus Beauveria bassiana was tested for its production of insecticidal proteins through a series of insect bioassays containing fungal protein extracts. These extracts were shown to be orally toxic to Plutella xylostella (diamondback moth) and Spodoptera frugiperda (fall armyworm). Assays involving protease treatments significantly decreased mortality indicating the presence of a protein based oral toxin. The following research tested transgenic tobacco plants expressing proteinase inhibitors from Brassica oleracea (cabbage) and Manduca sexta (tobacco hornworm) on the insect pests Helicoverpa zea (corn earworm) and Heliothis virescens (tobacco budworm). Insects fed transgenic tobacco were able to adapt to the recombinant proteinase inhibitors to varying degrees and resulted in no major impacts on insect growth and development. The last part of this study tested a novel insect resistance gene screening system. Agroinfiltrated tobacco transiently co-expressing genes encoding GFP with either a known insecticidal protein (Bt Cry1Ac) or a candidate gene (Brassica oleracea proteinase inhibitor, BoPI) were fed to larval H. zea. Insects fed the known insecticidal protein experienced high mortality. Insects fed tobacco expressing GFP and BoPI showed significant decreases in growth compared to those fed GFP only tissue. Insects feeding on GFP only tissue showed unexpected increases in growth and development compared to insects fed control tissue. Agroinfiltration coupled with an insect bioassay constitutes an efficient system for the evaluation of candidate insect resistance genes

MODELING AND SIMULATIONS FOR OPTIMIZATION OF MICROFLUIDIC MICROCAPACITOR ARRAYS OF BIOMIMETIC ARTIFICIAL MUSCLES FOR QUIET PROPULSION AND EXOSKELETAL LOCOMOTION

The technology that we focused on was the biomimetic actuation of microfluidic microcapacitors, which are electrostatically actuated structures that contract and function like biological muscles. Our thesis aims to find the optimal muscle-to-tendon ratio while expanding both the standard and gap design arrays and to find the respective force-density saturation values so predicted force output can be calculated for muscle fibers of a practical size. We also studied if a 3D virtual object can be a suitable model for the human operators’ examination of the artificial muscle and the optimization of its structure. Our results showed a maximum force density saturation of 8800 Pa and 6700 Pa when simulating the standard and gap array respectively with planar polarity wired artificial muscles. The optimal muscle-to-tendon ratio from the data gathered on the standard array simulations is approximately 9 to 1, meaning 90 percent of the surface area of the XY plane represents microfluidic capacitors and 10 percent is dielectric tendon material. The optimal muscle to tendon ratio from the data gathered on the gap array simulations is approximately 75 to 25, meaning 75 percent of the surface area of the XY plane are microfluidic capacitors, and 25 percent is both the dielectric material and gaps.Office of Naval Research, Arlington, VA, 22203-1995Outstanding ThesisCaptain, United States Marine CorpsCaptain, United States Marine CorpsApproved for public release. Distribution is unlimited

Application of high-resolution airborne data using individual tree crowns in Japanese conifer plantations

The original publication is available at www.springerlink.comArticleJOURNAL OF FOREST RESEARCH. 14(1):10-19 (2009)journal articl

Adversarial Coreset Selection for Efficient Robust Training

Neural networks are vulnerable to adversarial attacks: adding well-crafted, imperceptible perturbations to their input can modify their output. Adversarial training is one of the most effective approaches to training robust models against such attacks. Unfortunately, this method is much slower than vanilla training of neural networks since it needs to construct adversarial examples for the entire training data at every iteration. By leveraging the theory of coreset selection, we show how selecting a small subset of training data provides a principled approach to reducing the time complexity of robust training. To this end, we first provide convergence guarantees for adversarial coreset selection. In particular, we show that the convergence bound is directly related to how well our coresets can approximate the gradient computed over the entire training data. Motivated by our theoretical analysis, we propose using this gradient approximation error as our adversarial coreset selection objective to reduce the training set size effectively. Once built, we run adversarial training over this subset of the training data. Unlike existing methods, our approach can be adapted to a wide variety of training objectives, including TRADES, $\ell_p$-PGD, and Perceptual Adversarial Training. We conduct extensive experiments to demonstrate that our approach speeds up adversarial training by 2-3 times while experiencing a slight degradation in the clean and robust accuracy.Comment: Accepted to the International Journal of Computer Vision (IJCV). Extended version of the ECCV2022 paper: arXiv:2112.00378. arXiv admin note: substantial text overlap with arXiv:2112.0037

First Assessment of Mountains on Northwestern Ellesmere Island, Nunavut, as Potential Astronomical Observing Sites

Ellesmere Island, at the most northerly tip of Canada, possesses the highest mountain peaks within 10 degrees of the pole. The highest is 2616 m, with many summits over 1000 m, high enough to place them above a stable low-elevation thermal inversion that persists through winter darkness. Our group has studied four mountains along the northwestern coast which have the additional benefit of smooth onshore airflow from the ice-locked Arctic Ocean. We deployed small robotic site testing stations at three sites, the highest of which is over 1600 m and within 8 degrees of the pole. Basic weather and sky clarity data for over three years beginning in 2006 are presented here, and compared with available nearby sea-level data and one manned mid-elevation site. Our results point to coastal mountain sites experiencing good weather: low median wind speed, high clear-sky fraction and the expectation of excellent seeing. Some practical aspects of access to these remote locations and operation and maintenance of equipment there are also discussed.Comment: 21 pages, 2 tables, 15 figures; accepted for publication in PAS