MECHANICAL PROPERTIES OF GRAPHENE NANOPLATELET/EPOXY COMPOSITES

Due to their high specific stiffness, carbon-filled polymer composites are commonly used in the construction of structural components of subsonic fixed-wing aircrafts, such as the fuselage and control surfaces. In this work, neat epoxy (EPON 862 with EPIKURE Curing Agent W) was fabricated along with 1- 6 wt% of three types of GNP available from XG Sciences Inc. and 1-4 wt% of another type of GNP available from Asbury Carbons added to epoxy. The curing cycle for this epoxy was 121 °C for 2 hours followed by 177 °C for two hours. GNP are short stacks of individual layers of graphite that are newly developed and available at a low cost. XG Sciences Inc. xGnP®-M-15 has a platelets diameter of 15 μm and a thickness of 7 nm. xGnP®-M-5 has a diameter of 5 μm and a thickness of 7 nm. The specific surface area for both M-grades is 130 m2/g. xGnP®-C-300 has a diameter of 2 μm and a thickness of 2 nm with a specific surface area of 300 m2/g. Asbury Carbon’s TC307 GNP has a particle size \u3c1 μm diameter and ~8 layers (1.1 nm) thick and a specific surface area of 350 m2/g. Development of good dispersion techniques was the most important contribution of this project. Proper dispersion is very important for obtaining a good composite. For each of the four types of GNP used in this study, a unique dispersion method was developed. High shear mixing was used in combination with sonication to exfoliate the GNP and disperse it into the epoxy matrix. An optical microscope was used to monitor the dispersion during mixing progression. The composites were tested for their mechanical properties using typical macroscopic tensile testing, nanoindentation, and dynamic mechanical analysis. The addition of any of the four types of GNP resulted in an increase in the modulus (stiffness). The modulus can be predicted using the Halpin-Tsai model. The Halpin-Tsai model takes into account the mechanical properties of the polymer and the filler and also the filler geometry. The 2D randomly oriented filler Halpin-Tsai model was useful for predicting the modulus for xGnP®-M-15 in epoxy and xGnP®-M-5 in epoxy, this was confirmed visually through microscopy. The 3D randomly oriented filler Halpin-Tsai model predicted the modulus well for the xGnP®-C-300 and the TC307, microscopy visually confirmed that the filler was oriented in all three planes. From the mechanical properties, one type of GNP was chosen for use in a unidirectional carbon fiber composite. The continuous carbon fiber composites were tested via macroscopic tensile tests. The GNP chosen did not have an effect on the composite’s axial modulus, but increased the transverse modulus. The carbon fiber’s mechanical properties dominate over the GNP/epoxy properties in the axial direction. As far as current literature available, continuous carbon fiber has never been used as a reinforcement for GNP/epoxy composites

Augustana Seniors Fall 1883: William P. Anderson

William P. Anderson was a senior at Augustana College, Rock Island, Illinois, in the fall of 1883. His name appears in the college catalog of 1883 – 1884, along with his birthplace, the year of his birth, and a few other facts. From this start, we researched the genealogy and family history of William P. Anderson. This paper contains a short biography of William P. Anderson, a report on his ancestors, a report on his descendants, and some open questions for further research

Meiotic cellular rejuvenation is coupled to nuclear remodeling in budding yeast.

Production of healthy gametes in meiosis relies on the quality control and proper distribution of both nuclear and cytoplasmic contents. Meiotic differentiation naturally eliminates age-induced cellular damage by an unknown mechanism. Using time-lapse fluorescence microscopy in budding yeast, we found that nuclear senescence factors - including protein aggregates, extrachromosomal ribosomal DNA circles, and abnormal nucleolar material - are sequestered away from chromosomes during meiosis II and subsequently eliminated. A similar sequestration and elimination process occurs for the core subunits of the nuclear pore complex in both young and aged cells. Nuclear envelope remodeling drives the formation of a membranous compartment containing the sequestered material. Importantly, de novo generation of plasma membrane is required for the sequestration event, preventing the inheritance of long-lived nucleoporins and senescence factors into the newly formed gametes. Our study uncovers a new mechanism of nuclear quality control and provides insight into its function in meiotic cellular rejuvenation

Continuous or intermittent walking, the effect on glycated hemoglobin in sedentary employees during 10-week intervention

To examine long term changes on glycated hemoglobin in sedentary employees exposed to two different walking programs during a 10-week intervention. A total of 68 sedentary employees participated in a 10-week walking intervention and were randomly assigned to one of three groups: intermittent walking, continuous walking or control group. Hemoglobin A1cNOW+ device tested glycated hemoglobin and accelerometry assessed physical activity. Results showed glycated hemoglobin significantly decreased over the ten weeks (5.82±0.49, 5.66±0.44) F(1,64) =4.229, p=.044) in the continuous walking group. Post-Hoc test showed the continuous walking group was significantly affected, F=8.463, p=.009, with a large size effect n2=.297. There were no changes within the intermittent group (5.69±0.63, 5.63±0.6) or control group (5.59±0.6, 5.6±0.54) (p>0.05). Accelerometry showed a main effect of time by group interaction F(4,124) =4.688, p=0.001). Post-Hoc indicated that the continuous walking group took significantly longer bouts of moderate to vigorous intensity walking at week-6 compared to pre-test (p=0.006) at this could have influenced the results, there were no changes in the length of bouts in the intermittent or control groups (p>0.05). Sedentary employees who perform a moderate intensity continuous walking program show benefits in controlling blood glucose, thereby, reducing the risk of developing type 2 diabetes

Content management for dynamic, digital displays in academic libraries

Deakin University Library installed eight large multimedia screens in late 2013. Five touch-interactive screens, known as The Verge, became the central component of the installation and were positioned inside the main entrance of our Geelong Waterfront Campus Library. Based on our experience creating and maintaining displays for The Verge, this paper will discuss content types and patterns of success. We will also explore key considerations including user engagement, interaction and animation, physical space, hardware and software, resourcing, defining and measuring success. By reflecting on our experiences and considering research trends we draw conclusions to inform future development plans for digital displays in academic libraries

Can Philanthropy be Taught?

In recent years, colleges and universities have begun investing significant resources into an innovative pedagogy known as experiential philanthropy. The pedagogy is considered to be a form of service-learning. It is defined as a learning approach that provides students with opportunities to study social problems and nonprofit organizations and then make decisions about investing funds in them. Experiential philanthropy is intended to integrate academic learning with community engagement by teaching students not only about the practice of philanthropy but also how to evaluate philanthropic responses to social issues. Despite this intent, there has been scant evidence demonstrating that this type of pedagogic instruction has quantifiable impacts on students\u27 learning or their personal development. Therefore, this study explores learning and development outcomes associated with experiential philanthropy, and examines the efficacy of experiential philanthropy as a pedagogic strategy within higher education. Essentially, we seek to answer the question: Can philanthropy be taught

Serial interferon-gamma release assay (IGRA) testing to monitor treatment responses in cases of feline mycobacteriosis

The interferon-gamma release assay (IGRA) is used to diagnose cases of feline mycobacteriosis, but the use of serial testing to monitor treatment responses has not been evaluated in this species. From a population of cats that underwent IGRA testing for diagnostic investigation, individuals were identified with a pre- and end-of-treatment IGRA that passed control thresholds. The number of cats which reverted to negative at the end-of-treatment IGRA, changes in paired antigen-specific optical density (OD) values and differences in the pre-treatment antigen-specific OD values for those which underwent reversion were compared. Factors to explain reversion or recurrence of disease post-treatment were explored. Four of 18 cats (22%) reverted to negativity at the point of clinical resolution (p = 0.33), there was no difference in paired antigen-specific OD values (p ≥ 0.12), and cats that reverted did not have a lower baseline OD value (p = 0.63). No statistically significant factors were identified to predict reversion (p ≥ 0.08). Remaining positive at the end of treatment IGRA was not associated with recurrence of disease post-treatment (p = 0.34). Overall, these data suggest there is limited value in the use of the IGRA to monitor treatment responses in cats

Multiplex ligation-dependent probe amplification (MLPA) analysis is an effective tool for the detection of novel intragenic PLA2G6 mutations: Implications for molecular diagnosis

Phospholipase associated neurodegeneration (PLAN) comprises a heterogeneous group of autosomal recessive neurological disorders caused by mutations in the PLA2G6 gene. Direct gene sequencing detects 85% mutations in infantile neuroaxonal dystrophy. We report the novel use of multiplex ligation-dependent probe amplification (MLPA) analysis to detect novel PLA2G6 duplications and deletions. The identification of such copy number variants (CNVs) expands the PLAN mutation spectrum and may account for up to 12.5% of PLA2G6 mutations. MLPA should thus be employed to detect CNVs of PLA2G6 in patients who show clinical features of PLAN but in whom both disease-causing mutations cannot be identified on routine sequencin

A proteinaceous organic matrix regulates carbonate mineral production in the marine teleost intestine

Marine teleost fish produce CaCO(3) in their intestine as part of their osmoregulatory strategy. This precipitation is critical for rehydration and survival of the largest vertebrate group on earth, yet the molecular mechanisms that regulate this reaction are unknown. Here, we isolate and characterize an organic matrix associated with the intestinal precipitates produced by Gulf toadfish (Opsanus beta). Toadfish precipitates were purified using two different methods, and the associated organic matrix was extracted. Greater than 150 proteins were identified in the isolated matrix by mass spectrometry and subsequent database searching using an O. beta transcriptomic sequence library produced here. Many of the identified proteins were enriched in the matrix compared to the intestinal fluid, and three showed no substantial homology to any previously characterized protein in the NCBI database. To test the functionality of the isolated matrix, a micro-modified in vitro calcification assay was designed, which revealed that low concentrations of isolated matrix substantially promoted CaCO(3) production, where high concentrations showed an inhibitory effect. High concentrations of matrix also decreased the incorporation of magnesium into the forming mineral, potentially providing an explanation for the variability in magnesium content observed in precipitates produced by different fish species