Thermal Expansion of Three Closed Cell Polymeric Foams at Cryogenic Temperatures

The Space Shuttle External Tank (ET) contains the liquid H2 fuel and liquid oxygen oxidizer and supplies them under pressure to the three space shuttle main engines (SSME) in the orbiter during lift-off and ascent. The ET thermal protection system consists of sprayed-on foam insulation and pre-molded ablator materials. The closed-cell foams are the external coating on the ET and are responsible for minimizing the amount of moisture that condenses out and freezes on the tank from the humid air in Florida while it is on the pad with cryogenic propellant awaiting launch. This effort was part of the overall drive to understand the behavior of these materials under use-conditions. There are four specially-engineered closed-cell foams used on the tank. The thermal expansion (contraction) of three of the polyurethane and polyisocyanurate foams were measured from -423 F (the temperature of liquid hydrogen) to 125 F under atmospheric conditions and under vacuum. One of them, NCFI 24-124, is a mechanically-applied material and covers the main acreage of the tank, accounting for 77 percent of the total foam used. Another, BX-265, is also a mechanically-applied and hand-sprayed material used on the tank's "closeout" areas. PDL 1034 is a hand-poured foam used for filling odd-shaped cavities in the tank, Measurements were made in triplicate in the three primary material directions in the case of the first two materials and the two primary material directions in the case of the last. Task 1 was developing the techniques for getting a uniform heating rate and minimizing axial and radial thermal gradients in the specimens. Temperature measurements were made at four locations in the specimens during this initial development phase of testing. Major challenges that were overcome include developing techniques for transferring the coolant, liquid helium (-452 F), from its storage container to the test facility with a minimal transfer of heat to the coolant and control of the heating rate at the lowest temperatures

The role of hydrogen sulfide in doxorubicin-induced drug resistance in hepatocellular carcinoma cells

Doxorubicin is one of the most common chemical agents used in the treatment of cancers. Doxorubicin-treated cancer cells often develop drug resistance due to alterations in the trafficking and metabolism of the drug, which severely limits the drug’s effectiveness. This is seen at especially high rates in human hepatocellular carcinoma (HCC), the most common form of liver cancer. H2S is an important gasotransmitter and is involved in a variety of cellular functions and pathophysiologic processes. The role of H2S in drug resistance in cancer cells is still unclear. In this study, by using a human hepatocellular carcinoma cell line (HepG2), we found that NaHS (an H2S donor) was able to reduce cancer cell viability and colony formation in a doxorubicin dose dependent manner, while H2S alone did not show any effect. The expression of H2S-generating enzyme cystathionine gamma-lyase (CSE) but not cystathionine beta-synthase (CBS) was reduced by doxorubicin treatment. In addition, H2S promoted cellular retention of doxorubicin in HepG2 cells, possibly by suppressing the expression of ABCA1 and ABCG8, two drug efflux proteins. LXRα acts as a transcription factor for ABCA1 and ABCG8, however our findings showed that H2S had no effect on the protein expression and S-sulfhydration of LXRα, suggesting LXRα is not involved in H2S-regulated expressions of ABCA1 and ABCG8. In comparison with the parental cells, CSE expression was also reduced in doxorubicin-resistant cells. Exogenously applied NaHS reversed the drug resistance in doxorubicin-resistant cells. In conclusion, our study provides a novel solution for reversing drug resistance by targeting H2S signaling.Master of Science (MSc) in Biolog

Finnish Class Teacher’s Views on Multilingualism and Multilingual Children

In this thesis, Finnish class teachers were interviewed to learn more about their views on multilingualism and multilingual children. The following research questions were asked: 1. What are Finnish class teachers’ attitudes towards and beliefs about multilingualism? 2. How do Finnish class teachers report on their practice regarding multilingual primary school students? In six semi-structured interviews, the interviewed teachers could elaborate on their views, attitudes, beliefs, and practices related to multilingual students and multilingualism. To analyze the collected data, thematic analysis was used, and the theoretical lens of a monolingual habitus proposed by Gogolin was applied. Different expressions of multi- and monolingualism were observed in the interviewed Finnish class teachers. The two themes that were identified when analyzing the interview transcripts were: • Function of Language in School • Challenges of Teaching in Multilingual Schools. Aspects of monolingual habitus were present in the interviewed teachers, even those who taught English and Bilingual classes. Language as a resource was a subtheme in which beliefs and practices were particularly opposed. However, this habitus does not dominate all facets of teaching. Other languages are mostly seen as unproblematic when used in a social context. When language is used as a teaching tool, the language of instruction is positioned above other languages. The gap between beliefs and practices and the different contexts of language use indicates a habitus in transition. It would be interesting to investigate different contexts of Finnish primary education in future research, as this study was performed in a small area. This is especially relevant as equity and social justice are pillars of Finnish education. Therefore, it is also recommended that mixed-method research would be performed in this field in the future

Hoopoe: Simulation of Extreme Programming

Experts agree that “smart” communication are an interesting new topic in the field of cryptography, and systems engineers concur. In our research, we verify the visualization of DNS [34]. In this paper we propose a novel system for the simulation of the memory bus (Hoopoe), which we use to disprove that suffix trees can be made self-learning, interposable, and ubiquitous

Understanding Forage Quality Analysis

2 pp.This publication discusses forage characteristics important to dairy rations and explains quality parameters such as protein and fiber content and relative feed value

Biomechanical analysis and modeling of different vertebral growth patterns in adolescent idiopathic scoliosis and healthy subjects

<p>Abstract</p> <p>Background</p> <p>The etiology of AIS remains unclear, thus various hypotheses concerning its pathomechanism have been proposed. To date, biomechanical modeling has not been used to thoroughly study the influence of the abnormal growth profile (i.e., the growth rate of the vertebral body during the growth period) on the pathomechanism of curve progression in AIS. This study investigated the hypothesis that AIS progression is associated with the abnormal growth profiles of the anterior column of the spine.</p> <p>Methods</p> <p>A finite element model of the spinal column including growth dynamics was utilized. The initial geometric models were constructed from the bi-planar radiographs of a normal subject. Based on this model, five other geometric models were generated to emulate different coronal and sagittal curves. The detailed modeling integrated vertebral body growth plates and growth modulation spinal biomechanics. Ten years of spinal growth was simulated using AIS and normal growth profiles. Sequential measures of spinal alignments were compared.</p> <p>Results</p> <p>(1) Given the initial lateral deformity, the AIS growth profile induced a significant Cobb angle increase, which was roughly between three to five times larger compared to measures utilizing a normal growth profile. (2) Lateral deformities were absent in the models containing no initial coronal curvature. (3) The presence of a smaller kyphosis did not produce an increase lateral deformity on its own. (4) Significant reduction of the kyphosis was found in simulation results of AIS but not when using the growth profile of normal subjects.</p> <p>Conclusion</p> <p>Results from this analysis suggest that accelerated growth profiles may encourage supplementary scoliotic progression and, thus, may pose as a progressive risk factor.</p

Teacher Perceptions of Skills, Knowledge, and Resources Needed to Promote Social and Emotional Learning in Rural Classrooms

The incorporation of social and emotional learning (SEL) in schools has been shown to improve academic and psychological health of students. Research has been limited regarding implementation of SEL programs in rural communities, where student needs are heightened. The current study examined factors that could impact teachers’ intentions to be early adopters of a SEL curriculum in a rural community. Seventy-six teachers provided self-report data regarding perceptions of professional strengths, school climate, school resources for student support, ability to educate diverse students, ability to teach specific SEL domains, and intentions to be an early adopter of a SEL program. Present results indicated positive perceptions of school climate, one’s ability to teach diverse students, and one’s ability to teach self-management skills positively predicted intentions to be an early adopter of a SEL curriculum. Implications for rural schools are explored and recommendations for adoption of SEL curricula in rural schools are provided

Efficacy of personalized cognitive counseling in men of color who have sex with men: secondary data analysis from a controlled intervention trial.

In a previous report, we demonstrated the efficacy of a cognitively based counseling intervention compared to standard counseling at reducing episodes of unprotected anal intercourse (UAI) among men who have sex with men (MSM) seeking HIV testing. Given the limited number of efficacious prevention interventions for MSM of color (MOC) available, we analyzed the data stratified into MOC and whites. The sample included 196 white MSM and 109 MOC (23 African Americans, 36 Latinos, 22 Asians, eight Alaskan Natives/Native Americans/Hawaiian/Pacific Islander, and 20 of mixed or other unspecified race). Among MOC in the intervention group, the mean number of episodes of UAI declined from 5.1 to 1.6 at six months and was stable at 12 months (1.8). Among the MOC receiving standard counseling, the mean number of UAI episodes was 4.2 at baseline, 3.9 at six months and 2.1 at 12 months. There was a significant treatment effect overall (relative risk 0.59, 95% confidence interval 0.35-0.998). These results suggest that the intervention is effective in MOC