79717 research outputs found
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Drying and bleaching walnuts
Get PDFPublished November 1948. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalo
The Marion blackberry
Get PDFPublished February 1957. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalo
Controlling house ants
No full textPublished October 1951. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalo
Pedigree system used by poultry department
No full textPublished January 1931. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalo
Some factors in the control of surface and cheesy flavors in butter : recommended method of washing churns
Get PDFPublished April 1935. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalo
Exploration of the Phage Adsorption Mechanism in Mycobacterium abscessus Toward Improving the Efficacy of Current Antibiotics
Get PDFBackground: Mycobacterium abscessus (MAB) is a rapidly growing opportunistic pathogen that causes infections in immunocompromised patients. The highly impermeable cell wall and surface transport systems are major contributing factors to MAB intrinsic resistance, influencing the efficacy of bactericidal antibiotics. Phages are promising alternatives to antibiotics and have been used in clinics during difficult to manage cases such as drug-resistant and disseminated MAB infections. Interestingly, bacterial surface transport systems are employed by phages for attachment and entry into the host. While therapeutic phages are merely selected for their lytic activity, there is limited knowledge of molecular mechanisms of phage-MAB interaction. In this study, we aimed to establish the phage adsorption mechanisms. Method and Results: We have generated the bank of over 300 mycobacteriophages, and 131 were found to be lytic against the MAB19977 strain. To establish phages with wide-range activity between MAB strains, we screened the MAB phage library across 8 clinical isolates of cystic fibrosis patients. Twenty-five phages were lytic against all 8 of our clinical isolate strains. Assessment of phage lytic ability against phenotypically altered MAB in different nutrient and in vivo mimicking environments such as biofilm and phagosomal medias allowed us to identify lytic phages against MAB in more host- specific conditions. Our recent research has identified the MAB_0937c gene encoding
the MmpL10 drug efflux pump associated with MAB intrinsic resistance to antibiotics. We screened the mmpL10 gene knockout mutant against 28 selected phages and found that 21 phages had decreased lytic ability against the drug efflux pump mutant. The gene complementation has restored the phenotype. Furthermore, MmpL10 is involved in transporting a major cell wall component, 2,3-diacyltrehalose (DAT), on the cell surface. To rule out if phage resistance was due to deficiency in the efflux pump or lack of DAT on the cell wall, we tested selected phages against the MAB_0939 gene knockout mutant of the polyketide synthase (Pks). This key enzyme is involved in the DAT synthesis in mycobacteria. Our results indicate that Pks mutant exhibit resistance to the same phages as the MmpL10 mutant, validating DAT's importance for the phage adsorption process. By comparing phage lytic ability against MAB in the presence of efflux inhibitor compounds, we found 5 phages that showed decreased lytic function. In addition, we found that the use of the phages selected for their association with efflux pumps for phage adsorption in combination with antibiotics (amikacin) demonstrated the accelerated clearance of MAB when compared with the antibiotic treatment group alone. Conclusion: This study identified DAT as one of the receptors for phage adsorption into MAB. Additionally, we discovered phages that likely effect the function of efflux pumps. The combination of these phages with antibiotics significantly increased bacterial killing when compared with phage or antibiotic treatment alone
Understanding School Counselors' Perceptions of Esports and Igaming as a Career Choice
Get PDFOver the past 20 years, there has been a steady increase in the popularity of online gaming in the United States culture. There are many factors that have contributed to this spike in popularity, but the most significant are advancements in technology, televised competitions, social media, lucrative cash prizes, product endorsements, and scholarships (Morgan & Cole, 2023). From electronic sports (esports) to internet gaming (igaming), many of today's children, adolescents, and young adults perceive the virtual world of game play as both psychologically and financially rewarding. This has resulted in many young people pursuing professional gaming as a viable career choice. Undoubtedly, as more young people pursue esports and igaming as potential careers, high school counselors will find themselves interacting more with these students and providing them guidance into the world of professional esports and igaming.
These studies examined the high school counselors’ perceptions of esports and igaming as potential career choices for their students. The first study examined how high school counselors experience the phenomenon of esports as a career choice. The second study examined how high school counselors experience igaming as a career choice.
Interpretative phenomenological analysis (IPA) was chosen as the qualitative design for both studies. IPA is a hermeneutic circle of research where the researcher is involved in making sense of the experience while the participant reflects on the experience (Smith & Osborn, 2003). Participants were recruited from message board posts on high school counseling social media pages (e.g. Instagram, Facebook, and Twitter), personal emails, and through the following professional counseling and gaming organizations’ websites: American School Counselor Association (ASCA), the National Career Development Association (NCDA), and National Association of Collegiate Esports (NACE).
Six participants met the criteria of the study and were interviewed utilizing online video conferencing software (i.e. Zoom). Semi-structured interviews were conducted lasting between 45 and 80 minutes. Upon conclusion, the interviews were transcribed verbatim and the transcripts analyzed identifying major themes, along with similarities and differences in the experiences of the six participants. Following step-by-step analysis presented by Smith, Flowers, and Larkin (2009), a master table was created of the discovered themes. Additionally, strategies were used to increase trustworthiness, including peer debriefing, research positionality reflection, and member checking (Morrow, 2005).
The first manuscript examined how the participants (N=6) experienced esports as a career choice. The following five themes emerged from the data: (a) sense of limited job-specific knowledge, (b) marginalization of students due to stigma, (c) being guided by one’s professional identity and values of career counseling, (d) sense of determination to validate esports as a career choice, and (e) addressing feelings associated with navigating the professional relationship with students.
The second manuscript examined how the high school counselors (N=6) experienced igaming as a career choice. The following five themes emerged from the data: (a) underlying absence of knowledge about igaming as a career, (b) anticipatory navigation of student marginalization based on school counselors’ biases, (c) countering personal bias with professional values and identity as they ponder working with students, (d) struggling to see igaming as a viable career and emerging realization of igaming career awareness, and (e) anticipating a professional relationship with students pursuing igaming as a career choice.
The findings of both studies identified the need for more education, information and understanding of opportunities associated with esports and igaming as a career choice. The findings have multiple implications for research that are directed at the overall growth of knowledge in the experience of high school counselors working with students pursuing careers in these two phenomen
Molecular Dynamics Study of structural Evolution, Tensile Deformation and Nanoindentation of Monatomic Metallic Glasses
Get PDFMetallic glasses are attracting tremendous attention because of their fundamental significance and great potential to be used as structural or functional materials in engineering applications. Significant efforts have been devoted to studying their unique properties as well as their disordered nature. Metallic glasses possess much higher strength and elastic strain limit than their crystalline counterparts. Maximum allowed size of metallic glass products is being increased continuously as new alloy compositions with high glass forming ability are developed. However, the glassy structure and the mechanical behavior of metallic glasses are still far from thoroughly understood. This is partly due to the chemical complexity of multi-component metallic glasses that are examined in most studies. Newly discovered monatomic metallic glasses, such as Ta metallic glass, could bring new insights since they are consisted of only one type of element. This thesis thus focuses on investigating the atomic structure and mechanical properties of monatomic metallic glasses using molecular dynamics simulations. Comparisons are made to multi-component metallic glasses, represented by a specific Cu-Zr binary alloy.
We first found that Ta and V monatomic metallic glasses have a more active structural behavior than other binary or multicomponent metallic glasses at temperatures far below glass transition temperature. Secondly, we studied the initiation of shear transformation zones of metallic glasses under low uniaxial stress with different compositions, geometries and strain rates. We found very different response of surface atoms and interior atoms to the stress and related the difference to the potential energy and the coordination number. Lastly, we simulated nano-indentaion and tensile tests on Ta and Cu46Zr54 metallic glasses. Ta monatomic metallic glass has a decreasing hardness with increasing testing temperature. And it has a higher hardness and tensile strength than Cu46Zr54 metallic glass under the same normalized temperature. Furthermore, the hardness and the tensile strength of Ta metallic glass change more rapidly with temperature than Cu46Zr54 metallic glass. This is consistent with the more active structural evolution in Ta metallic glass that is likely due to the lack of chemical constraints in the monatomic metallic glass
Reduction of Salmonella spp. on In-shell Hazelnuts Using Continuous Steam Blanching and Prevalence of Salmonella spp. on In-shell Oregon Hazelnuts
Get PDFTree nuts have been implicated in a number of foodborne outbreaks and recalls in recent years linked to enteric pathogens, particularly Salmonella. Therefore, prior to distribution and marketing, it is necessary to understand the biological risks associated with the consumption of tree nuts and to find effective methods to inactivate foodborne pathogens. Steam treatment processes have been validated for use on California almonds, but little research has been conducted for in-shell hazelnuts. Hazelnuts grown in Oregon were recalled nearly annually from 2009 to 2017 and were implicated in an outbreak of E. coli O157:H7 that sickened 10 people in the Midwest and Canada in 2011 (Miller et al. 2014). In 2017, an outbreak of Salmonella Typhirium sickened 5 people and was traced to an 80-acre Oregon farm and nursery that sold between 32,000 to 48,000 pounds of raw in-shell hazelnuts directly to consumers from a road-side stand (Yada et al. 2019). To help characterize the biological risk of in-shell hazelnuts, we conducted a prevalence and amounts survey of Salmonella on in-shell hazelnuts grown in Oregon over two harvest years (2013-2014). In a separate study, we developed a steam treatment process that inactivates a 5-log reduction of Salmonella spp. on the surface of in-shell hazelnuts with minimal impact on final product quality.
For the Salmonella prevalence study, raw, green-dried in-shell hazelnut samples (n = 472) were collected by six of the largest hazelnut handlers in Oregon’s Willamette Valley and tested for the presence of Salmonella spp. using a modified method from the Food and Drug Administration’s (FDA) Bacteriological Analytical Manual (BAM). In-shell hazelnut samples (375 g) were enriched in 1:10 (w/v) lactose broth followed by selective enrichment in Rappaport-Vassiliadis Broth (RV) and Tetrathionate Broth (TT). Selective enrichments were streaked for isolation onto Hektoen Enteric (HE) and Xylose Lysine Desoxycholate (XLD) Agars. Suspected colonies displaying Salmonella spp. morphology were confirmed on CHROMagar Salmonella Plus. A most-probable-number (MPN) method (3 x 333, 33.3, 3.3 g) using the same cultural steps as the initial testing was used to determine Salmonella population levels on naturally-contaminated in-shell hazelnuts. The prevalence of Salmonella spp. by year was 21.7% (55/254) and 46.8% (102/218) for 2013 and 2014, respectively. Salmonella population levels ranged from 0.092 to 30.7 MPN/100 g, with an average of 2.6 MPN/100 g. These data will help support risk assessment strategies for the Oregon hazelnut industry.
In our second study, we evaluated the efficacy of steam blanching on the reduction of Salmonella spp. on the surface of in-shell hazelnuts as a potential thermal postharvest treatment for hazelnuts. A pilot-scale steam blancher was used to deliver a continuous steam treatment at atmospheric pressure. In-shell hazelnuts were inoculated (~8.5 log CFU/g) with a five-strain Salmonella spp. cocktail and exposed to steam (88°C) for 15 s, 1, 3, 5, and 10 min. Following steam treatment, hazelnut samples were transferred to 0.1% peptone water
(24°C), hand agitated 1 min, serially diluted, plated on Hektoen Enteric agar and incubated at 37°C for 24 h. D-values (0.82 to 1.53 min) were calculated based on plate counts. Salmonella spp. could not be recovered by enrichment after hazelnuts inoculated at 5 log CFU/g were treated with steam at 88°C for 10 min. These data will be useful when developing validated postharvest steam treatments for the hazelnut industry
Existence of Eta-Quotients for Squarefree Levels and Modular Type Supercongruences for Hypergeometric Functions
Get PDFIn this dissertation, we consider two problems in number theory, both relating to modular forms. First we consider when a given modular form can be expressed as a quotient in Dedekind's function. Rouse and Webb \cite{RW} have determined the integers such that the graded ring of modular forms is generated by -quotients. Arnold-Roksandich, James, and Keaton \cite{ARJK} provide counts of the number of linearly independent -quotients in for prime levels . The author, Anderson, Hamakiotes, Oltsik, and Swisher \cite{AAHOS} give necessary and sufficient conditions for the space to contain -quotients when is relatively prime to and is either prime or a product of two distinct primes. In this dissertation we generalize these necessary conditions for all levels which are relatively prime to . We then show that these conditions are sufficient as well for a large family of squarefree levels coprime to 6.
In the latter chapters of the dissertation we consider congruences between hypergeometric series and Fourier coefficients of modular forms. In 2003, Rodriguez Villegas \cite{RV} conjectured 14 supercongruences between hypergeometric functions arising as periods of certain families of rigid Calabi-Yau threefolds and the Fourier coefficients of weight 4 modular forms. Uniform proofs of these supercongruences were given in 2019 by Long, Tu, Yui, and Zudilin \cite{LTYZ}. Using p-adic techniques of Dwork \cite{Dwork}, they reduce the original supercongruences to related congruences which involve only the hypergeometric series. We generalize their techniques to consider six further supercongruences recently conjectured by Long \cite{Long20}. In particular we prove an analogous version of Long, Tu, Yui, and Zudilin's reduced congruences for each of these six cases. We also conjecture a generalization of Dwork's work which has been observed computationally and which would, together with a proof of modularity for Galois representations associated to our hypergeometric data, yield a full proof of Long's conjectures