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Degradable And Tunable Silyl Ether And Silyl Ester Containing Polymers: Synthesis, Characterization, Hyperbranching, And Applications
No full textThe development of degradable polymers has emerged as a significant focus within academic research, driven by increasing concerns over non-degradable waste. Previous studies showed the ability to degrade the Si-O-C bond in mild conditions, which was further taken into medical applications. The slow degradation time of the linear polymers and their nanoparticles in mild conditions led us to pursue two different solution paths. In this work we looked at hyperbranched poly(silyl ether)s A2+B3 and A2A’+B3 methodologies and silyl ester containing polymers. Hyperbranched polymers show potential in drug delivery applications as they are capable of loading more of the drug and releasing them faster. Silyl esters were studied previously and found to have faster degradation than silyl ethers. Hyperbranched polymers possess extensive surface areas, rendering them particularly suitable for nanoparticle formation, drug encapsulation, and polymer functionalization. The polymers are synthesized and subjected to characterization using NMR spectroscopy assess connectivity and branching. In this work we used 1H, 13C inverse gated, HSQCHC, HSQCHSi, HMBCHC, HMBCHSi, and HOESY NMR to differentiate the units of the polymers and calculate their degree of branching. The first system we studied was A2+B3, where we learned that varying the ratio of the two controls branching of the polymers. Our results showed that we were able to add excess SiH and OH groups to the backbone of the polymers for further functionalization. This was illustrated by end-capping the SiH groups with varying mono alcohols which can be changed based on applications. This idea led us to the A2A’+B3 system, where the A’ and the A2 groups are in competition. This led to lower branching, with a handle on the polymer for different applications. Poly(silyl ether-ester)s are prepared through a novel ring-opening reduction of cyclic anhydrides and hydrosilanes. This technique facilitates the transformation of symmetrical cyclic anhydrides into protected asymmetrical hydroxy-acids. We began with the reduction by tertiary hydrosilanes to form monomers, establishing the reaction and learning about the reaction, optimized conditions and the yields. Ring opening reductive polymerization was further derived, using dihydrosilanes and dihydro disilanes in order to form polymers containing silyl esters in the backbone. The polymers were found to have good thermal stability with two degradation peaks above 300 and 500 C coming from the silyl ethers and esters respectively. The polymers showed to degrade within six hours in the presence of water. The polymers showed the same propertied as previous works, differing in high yields, faster reactions, higher molecular weights, non-metal catalysts, and high efficiency. The carbonyls containing in the polymers can further be reduced by hydrosilanes, leading to hyperbranching. Further reduction occurs to the carbonyl leading to silyl acetal formations. Silyl acetals were found to degrade faster than esters and degrade at lower temperatures in comparison to silyl ethers and esters with temperatures around 200 C. Hyperbranched poly(silyl ether-silyl ester-silyl acetal)s were found capable of fully branching, reaching a degree of branching value of 1 while retaining their solubility. This is uncommon in A2+B3 systems, as the polymers retain solubility and the ability to gel in the presence of heat, typically 80 C. This work shows the ability to synthesize different degradable polymers with great potential in applications, both medical and industrial
Edith Freeman Thompson, ca. 1970
No full textPhotograph of Edith Freeman Thompson taken at 510 Reeves Drive, ca. 1970.https://commons.und.edu/gf-city-photos/1245/thumbnail.jp
You Can\u27t Have Our Braids
No full textTwo women with grey faces and white braids suspended in the air stand next to each other. They each have one eye and a series of lines across their faces. One woman is depicted wearing blue and the other in yellow, both with a repeating pattern across their garments.
Featured in the exhibition, Plain of Stars: An exhibition to uplift, acknowledge, and celebrate Indigenous students.https://commons.und.edu/native-art/1107/thumbnail.jp
Odd Fellows Block
No full textUndated photograph of the Odd Fellows Block.
The Odd Fellows Block, located at 23-25 S Fourth Street and 324 Kittson Ave in the Down Town Historic District of Grand Forks is a historic building built in 1888 as a home for the Odd Fellows meeting hall, which was situated on the third floor. The hall was fitted with a large and well-appointed lodge room, a banquet hall, and numerous smaller rooms.
The building is listed on the National Register of Historic Places and is home to the Urban Stampede coffee shop (6/9/2025) The building was home to the Odd Fellows as well as the Daughters of Rebekah, the lodges of the Ancient Order of United Workmen, the Knights of the Maccabees, the Order of Foresters, the Grand Army of the Republic, and the Royal Arcanum.
The Odd Fellows Block is architecturally significant in that it is one of two remaining Richardsonian Romanesque buildings extant in Grand Forks along with the St John\u27s Block. These buildings were, along with the now demolished Security Building, the most impressive in Grand Forks in the late 19th century. (theclio.com)https://commons.und.edu/gf-city-photos/1261/thumbnail.jp
The Effect of Physical Activity on Anxiety and Depression
No full textMental health challenges, such as anxiety and depression affect millions of Americans daily. While traditional treatments such as medication are effective, researchers are searching for other methods to combat the symptoms these conditions. Exercise has been that solution for researchers. Physical exercise provides a free and natural way to decrease symptoms of anxiety and depression. In as little as 30 minutes the release of endorphins and neurotransmitters in the body will make the body feel happy and relaxed. This takes away the feelings of worry and sadness one experiences when dealing with anxiety and depression. Incorporating exercise into one’s daily routine can be difficult at first but with patience and staying motivated, it can become a life changing habit. Despite the growing evidence, further research is needed to determine the optimal types and intensities of exercise for different individuals and mental health conditions. Physical exercise provides a powerful and accessible alternative to alleviate symptoms of anxiety and depression
From Screen to Reality: The Potential Correlation Between Video Games and Aggression
Get PDFThis paper discusses studies pertaining to video games and its potential influence on behavior\u27s such as aggression and moral disengagement
Between the Layers
No full textInformation provided by Zachary Miller:
Peggy Thurston Farrell (American)
Between the Layers, 1981
Silkscreen
Purchased with funds from the Myers Foundations
University Art Collections: Art & Design Study Collection
Peggy Thurston Farrell studied art education at Carroll College in 1972 and later obtained a Master of Fine Arts from the University of Wisconsin-Milwaukee. Her work has been showcased globally, throughout her career. Her current work has moved towards symbolism and three-dimensional presentations.
Between the Layers owes its origins to underground treasures and artifacts, which inspired the production of this work. Hard-edge painting and post-painterly abstraction are two artistic movements, originating in the 1950s and ending in the 1970s, that share similarities to Thurston Farrell’s work. These similarities are a consequence of the temporal relation of her 1981 Between the Layers silkscreen to artwork of the 1980s. Abstract art of that era was largely a combination of earlier abstract movements.
Part of a diptych, other half is missing.https://commons.und.edu/uac-all/4917/thumbnail.jp
Daron Norwood
No full textDaron Norwood at the Chester Fritz Performing Arts Centerhttps://commons.und.edu/performing-arts-photos/1055/thumbnail.jp