Photochemical reactions of lignin: Opportunities for valorisation

Lignin is the second most abundant biopolymer after cellulose and is the largest bio-based source of aromatic compounds. However, its heterogeneous and recalcitrant structure makes it difficult to depolymerise for use in renewable chemicals production. Photochemical reactions can be performed at mild conditions and can achieve efficient reaction pathways without the use of additional reagents. The potential efficiency gains in terms of energy and use of materials have led to renewed interest in photochemistry research, as we seek to improve the environmental sustainability of industry.Concepts for valorisation of lignin through heterogenous and homogenous photocatalysis are currently being investigated. Although this photocatalyst research has shown some encouraging results, the synthesis, separation, and recycling of catalysts would add significant costs to a process. If it were possible to induce direct photochemical reactions with ultraviolet light, the difficulties associated with catalysis could be avoided, and it would bring a photochemical lignin valorisation concept closer to feasibility.This thesis deals with the topic of how ultraviolet light can induce changes in lignin. The contents in Paper I describe our early work, which demonstrated that UV light causes changes to functional groups in lignin and that UV light can be used to extract lignin from sawdust. In our more recent experiments, we use 280 nm light from UV-LEDs using a homemade 3D printed photoreactor, the details of which are covered in Paper II. The results presented here also include a comparison between acetonitrile and aqueous NaOH as solvents for the photoreactions. The evaluation of whether benzophenone can be used as a photosensitiser to increase the reaction rate or yield toward desired products in reactions of Kraft lignin and 2-(benzyloxy)phenol, a model compound used to represent an ether bond between two phenolic rings, is covered in Paper III. We also needed to access whether our conclusions are robust against changes in lignin concentration and light intensity, and an analysis of this is included in the results and discussion. Lignin has also been observed to act as a photocatalyst. The beginning of an investigation into this phenomenon is covered in this thesis using the photooxidation of methanol to formate as an example. 1H NMR is the primary analysis technique used in this work. Results based on GC-MS and diffusion NMR are included to demonstrate their intended use in future work. The analysis across all areas focuses on using the analysis methods to estimate reaction rates and selectivity toward certain products, and aims to understand the connections between these results and the details of the reactions.The results gathered so far have laid the groundwork for understanding the complex relationships between the properties of lignin, reaction conditions, and changes which occur upon irradiation with UV light. The end of the thesis discusses future plans for increasing our understanding of these photoreactions

Low Blood Sugar Impacts Athletic Performance in Kids with Diabetes

Low blood sugar has a negative effect on the athletic ability of adolescents with type 1 diabetes. It also affects their ability to respond to visual stimuli.York's Knowledge Mobilization Unit provides services and funding for faculty, graduate students, and community organizations seeking to maximize the impact of academic research and expertise on public policy, social programming, and professional practice. It is supported by SSHRC and CIHR grants, and by the Office of the Vice-President Research & Innovation. [email protected] www.researchimpact.c

An overview of the Salish Sea Marine Survival Project: U.S.-Canada integration

The Salish Sea Marine Survival Project (Project) is a multi-year transboundary effort to determine the primary factors affecting juvenile salmon and steelhead survival in the Salish Sea. The Project, coordinated by nonprofits Long Live the Kings (U.S.) and the Pacific Salmon Foundation (Canada), brings together multidisciplinary expertise from over 20 Federal and State agencies, Tribes, academia and nonprofit organizations on both sides of the U.S.-Canada border. Through the development of a comprehensive, ecosystem-based research framework; coordinated data collection and standardization; and improved information sharing, the Project will help managers better understand the critical relationship between salmon and the Salish Sea. This transboundary initiative began in 2012 and will last seven years. Foundational reports include the Pacific Salmon Foundation’s Strait of Georgia Chinook and Coho Proposal (2009) and subsequently the Hypotheses and Preliminary Research Recommendations for Puget Sound (2012). In November 2012, a workshop with 90 participants was held to receive feedback from the broader scientific community regarding the critical elements of a US-Canada research program. The foundational and workshop summary reports are available at the Project web site (www.marinesurvivalproject.org). Science teams are now using this information to develop and implement the necessary research. We will present an overview of the Salish Sea Marine Survival Project, describing its history, leading hypotheses for poor survival, current status in research development and implementation, and how this work will contribute to Salish Sea sustainable resource management and recovery efforts. We will highlight the multi-disciplinary, collaborative nature of this project and the role of non-governmental organizations in aiding this large-scale initiative

Can lizard embryos survive climate warming? Thermal constraints on the physiology of developing Eastern fence lizards

Sublethal stressors will likely mediate an organism’s response to climate change. Mobile animals can change their behavior to maintain temperatures within preferred ranges. However, animals in immobile life stages are particularly vulnerable to warming. For example, lizard embryos experience recurrent thermal stress as they develop in shallow nests with daily temperature fluctuations. Nesting temperatures above 41.5°C can be lethal to Eastern fence lizard (Sceloporus undulatus) embryos. Although that is beyond the range experienced at current nest sites, rapid warming will push nest conditions toward critical limits. Therefore, it is important to examine the effects of sublethal high nest temperatures on developing lizards. We reared S. undulatus embryos under three thermal regimes—one to simulate contemporary nest conditions with a maximum daily temperature (Tmax) of 32.1°C, and two regimes to simulate warming scenarios in which the Tmax was raised to 35.6°C and 39.1°C. We tracked changes in physiology and survival through embryonic development, and we measured growth and metabolic rates of surviving hatchlings. Results showed reduced embryo survival and decreased hatchling growth for lizards reared under sublethal warming, suggesting that thermal constraints on the physiology of developing Eastern fence lizards may limit the persistence of the species under climate warming

A 3D printed photoreactor for investigating variable reaction geometry, wavelength, and fluid flow

Research in the field of photochemistry, including photocatalysis and photoelectrocatalysis, has been revitalized due to the potential that photochemical reactions show in the sustainable production of chemicals. Therefore, there is a need for flexible photoreactor equipment that allows for the evaluation of the geometry, light wavelength, and intensity of the vessel, along with the fluid flow in various photochemical reactions. Light emitting diodes (LEDs) have narrow emission spectra and can be either pulsed or run continuously; being flexible, they can be arranged to fit the dimensions of various types of the reactor vessel, depending on the application. This study presents a 3D printed photoreactor with the ability to adjust distances easily and switch between high-power LED light sources. The reactor design utilizes customized printed circuit boards to mount varying numbers and types of LEDs, which enables multiple wavelengths to be used simultaneously. These LED modules, comprised of heat sinks and cooling fans, fulfill the higher heat dissipation requirements of high-power LEDs. The flexibility of the reactor design is useful for optimizing the reaction geometry, flow conditions, wavelength, and intensity of photochemical reactions on a small scale. The estimates for incident light intensity under five possible reactor configurations using ferrioxalate actinometry are reported so that comparisons with other photoreactors can be made. The performance of the photoreactor for differing vessel sizes and distances, in both the flow and batch modes, is given for a photochemical reaction on 2-benzyloxyphenol-a model substance for lignin and applicable in the production of biobased chemicals

Blood Glucose Levels and Performance in a Sports Camp for Adolescents with Type 1 Diabetes Mellitus: A Field Study

Background. Acute hypo- and hyperglycemia causes cognitive and psychomotor impairment in individuals with type 1 diabetes mellitus (T1DM) that may affect sports performance. Objective. To quantify the effect of concurrent and antecedent blood glucose concentrations on sports skills and cognitive performance in youth with T1DM attending a sports camp. Design/Methods. 28 youth (ages 6–17 years) attending a sports camp carried out multiple skill-based tests (tennis, basketball, or soccer skills) with glucose monitoring over 4 days. Glucose levels at the time of testing were categorized as (a) hypoglycemic (<3.6 mM); (b) within an acceptable glycemic range (3.6–13.9 mM); or (c) hyperglycemic (>13.9 mM). Results. Overall, sports performance skill was ∼20% lower when glucose concentrations were hypoglycemic compared to either acceptable or hyperglycemic at the time of skill testing (P < .05). During Stroop testing, “reading” and “color recognition” also degraded during hypoglycemia, while “interference” scores improved (P < .05). Nocturnal hypoglycemia was present in 66% of subjects, lasting an average of 84 minutes, but this did not affect sports skill performance the following day. Conclusions. Mild hypoglycemia markedly reduces sports skill performance and cognition in young athletes with T1DM