Bringing broader impacts to the community via university K-12 partnerships: growth in and seed quality of Betula neoalaskana Sargent

Thesis (M.S.) University of Alaska Fairbanks, 2020Betula neoalaskana Sargent is the most abundant birch species in Alaska. All parts of the tree can be used in creating timber and non-timber products, and birch stands provide high-value ecosystem services for ecotourism and outdoor recreational purposes. For these reasons, the OneTree Alaska program of the University of Alaska Fairbanks uses Interior Alaska white birch as the centerpiece of its work. This M.S. thesis is a contribution to OneTree Alaska's goal of raising the public's understanding of the effects of Interior Alaska's lengthening growing season on the growth and reproduction of the local birch resource. Specifically, the thesis relates to the growth and reproduction of the offspring of the original "one trees" harvested on Nenana Ridge in October 2009. The saplings have been growing in the Generation OneTree Research Plot in the T-field, north of the Smith Lake on the University of Alaska Fairbanks campus, since June 2011 and represent half-sibling families reared from the seed of 8 maternal trees. As seedlings, they were reared for growing seasons of variable length, both by students at the Watershed Charter School of the Fairbanks North Star Borough and by OneTree personnel in a University of Alaska Fairbanks growth chamber. Prior to this study, end of year measurements had been taken of the young trees in the T-field for all but one year and established that the length of the first growing season persistently affected the number of stems and the diameter at breast height (DBH) of the main stems. New findings in this thesis show that the elevation difference among trees impacts the number of infructescences and germination rates but not the number of male catkins. At least for the 2018 seed crop, seeds from trees planted at higher elevations in the T-field showed higher germination rates than those planted at lower elevations, while they produce fewer infructescences at up slope. Other findings demonstrate that sibling family does not have an effect on either vegetative or reproductive growth. Instead, the length of the first growing season provides for a diversity of canopy shapes across sibling families. The most significant finding is the effect of elevation on female reproductive growth: It suggests a number of next steps, tools, and analysis to better understand environmental variables that work alongside elevation in determining growth and reproductive success. Soil moisture and pH (H2O), Carbon/Nitrogen ratio, Inductively Coupled Plasma Mass Spectrometry (ICP-MS) to determine micronutrient composition, sensors to capture wind speed/direction and solar radiation, photosynthetic traits, and chlorophyll concentration measurements could all be valuable in further elucidating the hypotheses being advanced by this research regarding the interactions between changing environment and reproduction.Heiwa Nakajima FoundationChapter 1: Introduction -- 1.1. Betula neoalaskana Sargent: boreal forest and birch in Alaska -- 1.2. OneTree Alaska -- 1.2.1. Broader Impacts Activity -- 1.2.2. STEM to STEAM -- 1.2.3. Concept and History -- 1.3. Justification. Chapter 2. T-field Vegetative and Reproductive growth -- 2.1. Introduction -- 2.1.1. Problem statements -- 2.1.2. Hypothesis -- 2.2. Material, Methods and Timeline of T-field -- 2.2.1. Original experiment from 2009 to 2011 -- 2.2.2. LiDAR data and GIS Analysis for T-field in 2018 -- 2.2.3. Growing condition: precipitation and temperature data -- 2.2.4. Stem numbers, Height, and DBH measurement in 2018 by a class -- 2.2.5. Reproduction assessment -- 2.2.6. Statistic analysis -- 2.3. Results -- 2.3.1. Vegetative data of T-field in 2018 -- 2.3.2. Reproductive growth data of T-field in 2018 -- 2.4. Discussion -- 2.4.1. The effect of the first growing seasons -- 2.4.2. The effect of elevation and the distance from the edge of the sub-canopy -- 2.4.3. Resemblance from the former studies on birch and critiques. Chapter 3. Germination Experiment -- 3.1 Introduction -- 3.1.1. Problem statement -- 3.1.2. Hypothesis -- 3.2 Material, Methods, and Timeline -- 3.2.1. Seed sampling from T-field in 2018 -- 3.2.2. Cupcake method -- 3.2.3. Growing conditions in the greenhouse -- 3.2.4. Statistic analysis -- 3.3. Qualification of the cupcake method -- 3.3.1. Result of the statistic analysis -- 3.3.2. Price of the cupcake method -- 3.3.3. Recommendation -- 3.4. Germination results -- 3.4.1. The increment of germination over 21 days -- 3.4.2. The numbers of germination on 21st day -- 3.5. Discussion -- 3.5.1. Reproductive ecology in life strategy and seed vigor -- 3.5.2. Resemblance from the former studies and questions for the future. Chapter 4. General Discussion and Conclusion -- 4.1. General discussion -- 4.2. General conclusion -- 4.3. Further research suggestions -- 4.4. Germination experiment protocol for citizen scientists -- 4.4.1. Introductory remarks -- 4.4.2. Find Birch -- 4.4.3. Find and get birch seeds -- 4.4.4. Prepare tray and soil -- 4.4.5. Sow seeds -- 4.4.6. Take care of seeds -- 4.4.7. Find germination -- 4.5. Afterthoughts -- Literature cited

Performance of a Biodegradable Composite with Hydroxyapatite as a Scaffold in Pulp Tissue Repair

Vital pulp therapy is an important endodontic treatment. Strategies using growth factors and biological molecules are effective in developing pulp capping materials based on wound healing by the dentin-pulp complex. Our group developed biodegradable viscoelastic polymer materials for tissue-engineered medical devices. The polymer contents help overcome the poor fracture toughness of hydroxyapatite (HAp)-facilitated osteogenic differentiation of pulp cells. However, the composition of this novel polymer remained unclear. This study evaluated a novel polymer composite, P(CL-co-DLLA) and HAp, as a direct pulp capping carrier for biological molecules. The biocompatibility of the novel polymer composite was evaluated by determining the cytotoxicity and proliferation of human dental stem cells in vitro. The novel polymer composite with BMP-2, which reportedly induced tertiary dentin, was tested as a direct pulp capping material in a rat model. Cytotoxicity and proliferation assays revealed that the biocompatibility of the novel polymer composite was similar to that of the control. The novel polymer composite with BMP-2-induced tertiary dentin, similar to hydraulic calcium-silicate cement, in the direct pulp capping model. The BMP-2 composite upregulated wound healing-related gene expression compared to the novel polymer composite alone. Therefore, we suggest that novel polymer composites could be effective carriers for pulp capping