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Effect of gas nanobubbles on the efficacy of peracetic acid and chlorine against Escherichia coli and Listeria monocytogenes

Effect of gas nanobubbles on the efficacy of peracetic acid and chlorine against Escherichia coli and Listeria monocytogenes

Primary Author: Arshdeep Singh

Faculty Sponsor: Minto Michael

 

Primary College/Unit: Agricultural, Human and Natural Resource Sciences

Category: Agricultural and Natural Resource Sciences

Campus: Pullman

 

Abstract:

 

Nanobubbles are defined as fine bubbles with diameter varying from 20 to 200 nm with distinctive surfactant properties because of their small size. Nanobubbles are proven effective in irrigation systems, fisheries, wastewater treatments and dentistry. This research was conducted to study the impact of gas nanobubbles on the efficacy of commonly used antimicrobials in food industry. This study was conducted as a completely randomized block design (three replications). Air, CO2 and N2 were used to generate nanobubbles in water. Peracetic acid and chlorine were used to make the nanobubble-antimicrobial solutions and were tested against Escherichia coli O157:H7 and Listeria monocytogenes. Antimicrobials mixed with water without any gas acted as controls. Nine-milliliter of antimicrobial solutions were taken into individual test tubes and inoculated with 1 ml of individual microbial inoculum. After the holding time of 1.5 and 3 min, 1 ml of the sample was taken, neutralized with Dey-Engley broth, and plated on brain heart infusion agar. pH and Eh of antimicrobial solutions were measured before and after the addition of master inoculum. After 3 min for E. coli, CO2 nanobubbles with chlorine was the most effective treatment with 6.4 log reductions as compared to 4.2 log reductions in control. For L. monocytogenes, CO2 nanobubbles with peracetic acid was most lethal treatment with 4.6 log reductions compared to 1.9 log reduction in control. This study demonstrated that efficacy of various antimicrobials can be increased by incorporating gas nanobubbles. Further, this method can be tested against other pathogens in different food matrices.

 

Modeling the Impact of Staff to Patient Ratios on MRSA Acquisition in an Intensive Care Unit

Modeling the Impact of Staff to Patient Ratios on MRSA Acquisition in an Intensive Care Unit

Primary Author: Stephanie Sikavitsas Johnson

Faculty Sponsor: Eric Lofgren

 

Primary College/Unit: College of Veterinary Medicine

Category: Medical and Life Sciences

Campus: Pullman

 

Abstract:

 

Staff-to-Patient ratios in hospitals impact several hospital acquired infections (HAIs). Intuitively, increasing the number of nurses and doctors in an intensive care unit (ICU) should impact rates of HAI transmission by reducing the number of patients per provider, allowing less patient-patient interaction. Designing a study to determine how different staffing ratios would affect HAIs is difficult to in person because of lots of different factors that make each hospital and unit unique. Mathematical modeling can be used instead to simulate how staffing ratios affect methicillin-resistant S. aureus (MRSA) being acquired in a 15-bed ICU.

 

We varied the number of doctors in the ICU from one to three. For each doctor scenario, the nurse -patient ratio was 1:1, 1:2.5, 1:3. And 1:5. We ran each model 1000 times, with each time simulating 1 year in the ICU. The outcome was the mean number of MRSA acquisitions in one year for each of the 12 models. Our baseline model we compared everything to was the single doctor, 1:3 nurse-patient ratio model.

 

Adding more doctors slightly decreased the number of acquisitions, with the steeper decline going from one doctor to two. Going from a 1:3 nursing ratio to 1:1 ratio decreased MRSA acquisition by 64%. Increasing to a 1:5 ratio raised acquisitions 21.5%. These results suggest reduction in provider contact may have an impact on HAI rates. Appropriate staffing should be considered in infection control guidelines, and the cost of staffing be weighed against its impact on infection prevention.

 

The effect of mindsets and ex-offenders’ redemptive narratives on managers’ willingness to consider hiring ex-offenders

The effect of mindsets and ex-offenders’ redemptive narratives on managers’ willingness to consider hiring ex-offenders

Primary Author: Eunjeong Shin

Faculty Sponsor: Jerry Goodstein

 

Primary College/Unit: Carson College of Business

Category: Business, Communication, and Politial Sciences

Campus: Pullman

 

Abstract:

Principal Topic

The United States has been one of the most punitive countries with the highest rate of incarceration. Previous research has suggested that employers play an essential role in reintegrating ex-offenders back to the community as they offer job opportunities. This paper aims to investigate managers’ mindsets that influence their willingness to consider hiring ex-offenders. I explored two categories of managers’ mindsets – justice mindsets (punitive and restorative mindsets) and fixed vs. growth mindsets – and how ex-offenders’ use of redemptive narratives moderate the relationships between managers’ mindsets and their hiring decisions.

 

Method

We collected data from 251 U.S. managers from various industries through Amazon M-Turk. All participants were randomly assigned to read one of the two versions of the scenarios (either high or low redemptive narrative) and were then asked to indicate their willingness to consider hiring the applicant with a 7-points Likert scale. I adopted the existing justice mindsets and fixed vs. growth mindset scale to measure managers’ mindsets. We used SPSS hierarchical regression analysis to analyze the data.

 

Results / implications

The results indicated that all four mindsets significantly influenced the managers’ hiring decision, supporting our hypotheses. Managers with punitive or fixed mindset were less willingness to consider hiring ex-offenders while managers with restorative or growth mindset were more willingness to consider hiring ex- offenders. The moderating effect of redemptive narrative was not supported. Interestingly, however, contrary to our expectation, high usage of ex-offender’s redemptive narratives was negatively related to managers’ willingness to consider hiring the applicant.

 

Diverse Parents’ Perspectives and Roles in Supports for Children with Challenging Behavior

Diverse Parents’ Perspectives and Roles in Supports for Children with Challenging Behavior

Primary Author: Kathryn Sheridan Stiefel

Faculty Sponsor: Don McMahon

 

Primary College/Unit: College of Education

Category: Arts and Education Sciences

Campus: Pullman

 

Abstract:

 

PRINCIPAL TOPIC

Responding to the needs and concerns of parents of children with challenging behavior is critical for collaboration across stakeholders. However, in the growing body of research on behavior challenges in youth, the perspectives and roles of parents in discipline and intervention are not always clearly stated. The purpose of this systematic literature review is to explore the themes of the extant research literature at the intersection of “challenging behavior” and “parent roles” across differing regions and cultures.

 

METHOD

To determine patterns across the research literature, data was extracted from eight selected articles included in this systematic review. In total, five overarching themes were identified, including: a lack of diversity in research, culturally responsive practices, required elements for sustainable interventions, behavior modification and management strategies, and the importance of community.

 

RESULTS

The implications of this review may be helpful for parents seeking treatment and/or interventions for their family, or for educational stakeholders that would like to learn more about parents’ perspectives and perceptions of a variety of effective supports at the family and community level. Moving forward, it is the goal of the researcher to capture wider representation of parents’ perspectives and roles. Next steps in this research will include expanding the base of journals searched and search criteria utilized. Additionally, incorporating perspectives of the children in these families with challenging behavior is recommended, so that these children at the heart of this research can be represented in determining the most effective supports for themselves and their families.

 

Determination of thermal inactivation parameters of Salmonella in nonfat dry milk and whole milk powder during four months storage

Determination of thermal inactivation parameters of Salmonella in nonfat dry milk and whole milk powder during four months storage

Primary Author: Amninder Singh Sekhon

Faculty Sponsor: Minto Michael

 

Primary College/Unit: Agricultural, Human and Natural Resource Sciences

Category: Agricultural and Natural Resource Sciences

Campus: Pullman

 

Abstract:

 

Principal Topic- Foodborne pathogens such as Salmonella can endure dry environments of milk powders for extended periods of time due to increased adaptability at low water activity (aw) levels and proliferate when powders are hydrated. This study focused to compare survivability and thermal resistance of Salmonella in NFDM and WMP stored for 120 days.

 

Methods- This study was designed as completely randomized with three replications. Milk powders were spray inoculated with 5-serovar Salmonella cocktail and dried back to original pre-inoculation aw. The D-values of Salmonella in inoculated NFDM and WMP were determined periodically (every 30 days, starting from day-one). The D and z-values were also performed for hydrated forms of NFDM and WMP. Rehydration (13% total solids w/v) was performed on days of performing D- and z-value study. Five separate thermal death time disks containing 5g or 5 mL of respective sample were transferred into five thermal-death-time, sealed and placed in hot-water baths set at 80, 85 and 90°C for inoculated powder, and 59, 62 and 65°C for hydrated inoculated powder. Samples were held for 0 to 56 minutes in hot-water baths and quickly transferred to cold-water baths at pre-determined time intervals. The samples were enumerated using injury-recovery media, and D- and z-values were calculated.

 

Results- During storage, heat resistance of Salmonella in WMP was statistically higher than NFDM. D-values of Salmonella on day 120 in WMP were 24.6, 11.4, and 7.0 minutes at 80, 85 and 90°C respectively as compared to 21.9, 9.2, and 5.2 min in NFDM.

 

Grain Protein Content Stability and Genomic Selection for Predicting the Grain Protein Content in Wheat

Grain Protein Content Stability and Genomic Selection for Predicting the Grain Protein Content in Wheat

Primary Author: Karansher Sandhu

Faculty Sponsor: Arron Carter

 

Primary College/Unit: Agricultural, Human and Natural Resource Sciences

Category: Agricultural and Natural Resource Sciences

Campus: Pullman

 

Abstract:

 

Grain protein content (GPC) is controlled by a complex genetic system, yet it is an important quality determinant for hard red spring wheat as it has a positive effect on bread and pasta quality. GPC is highly variable among genotypes and is also variable across different environments. Thus, understanding the genetic control of wheat GPC and identifying genotypes with less variation under different environments, is an important breeding goal. The objectives of this research were to identify wheat families having less variation for GPC across environments and identify quantitative trait loci (QTL) controlling the stability of GPC. We used 650 recombinant inbred lines from the spring wheat nested association mapping (NAM) population derived from 26 diverse founder parents each crossed to one common parent, ‘Berkut’. The population was phenotyped for three years (2014-16). Genomic prediction (GP) models were developed to predict GPC and GPC stability. The GPC was highly variable between these families across environments. We selected seven families that had less variation of GPC. The stability index of each genotype was obtained by Finlay-Wilkinson regression. Genome-wide association study (GWAS) identified eight significant QTLs using a Bonferroni correction of 0.05. This study also demonstrated that genome-wide trait prediction with ridge regression/best linear unbiased estimates reached up to r = 0.69. Overall, this study helped in the identification of QTLs controlling the stability of GPC. The genomic prediction accuracies suggest that genomic selection can be used to select breeding lines having higher protein content and improve genetic gain more rapidly.

 

Optimizing the Production of Stem-cell-based Cartilage for Arthritis Treatment

Optimizing the Production of Stem-cell-based Cartilage for Arthritis Treatment

Primary Author: Olivia Reynolds

Faculty Sponsor: Bernard Van Wie

 

Primary College/Unit: Voiland College of Engineering and Architecture

Category: Engineering and Environmental Science

Campus: Pullman

 

Abstract:

 

Principle topic

Osteoarthritis (OA), the degradation of articular cartilage tissue which lines joints, affects 30 million adults in the United States. There are few effective treatment options for OA; however, stem-cell-based therapy is a promising emerging treatment as stem cells can form new healthy cartilage. The use of chemical growth factors and anti-inflammatory compounds, as well as the co-culture of stem cells with native cartilage cells can enhance cartilage formation and promote the production of critical structural proteins such as glycosaminoglycans (GAG) and collagen. However, the optimum combination of these factors is unknown. Thus, this work investigated the combined roles of the growth factor dexamethasone, the anti-inflammatory compound alpha-tocopherol, and the ratio of stem cells to cartilage cells in an effort to determine an optimum combination and improve the quality of engineered cartilage tissue.

 

Method

In this work, dexamethasone concentration, alpha-tocopherol concentration, and stem cell percentage were varied using a Box-Behnken fractional factorial design scheme. Following 21 days of cell culture, total collagen, GAG, and DNA were measured for each experimental group to quantify the amount of cartilage-specific proteins produced. Data were analyzed to determine the culture conditions which resulted in the maximum quantity of collagen and GAG as these proteins indicate cartilage formation.

 

Results/implications

The results of this study showed that the highest protein production occurred at low stem cell percentages, low to moderate anti-inflammatory concentrations, and moderate growth factor concentration. These results may be used to improve the production of cartilage for applications in OA treatment.

 

Exploring the Effectiveness of Academic Probation/Reinstatement Interventions on Academic Success Behaviors and Strategies of Undergraduate Students

Exploring the Effectiveness of Academic Probation/Reinstatement Interventions on Academic Success Behaviors and Strategies of Undergraduate Students

Primary Author: Katie Reilly

Faculty Sponsor: Olusola Adesope

 

Primary College/Unit: College of Education

Category: Arts and Education Sciences

Campus: Pullman

 

Abstract:

PRINCIPAL TOPIC

Undergraduate students who are on academic probation/reinstatement due to falling short of expected GPA standards set by colleges and universities are at high risk of dropping out or being dismissed. To retain these students and to support students at-risk of academic failure, many colleges and universities have focused on providing interventions to increase retention and academic success. The goal of this pilot study was to examine the impact of academic support interventions that possibly contribute to the academic success and retention of students who are not meeting WSU academic standards.

 

METHOD

This study sought to answer the following research questions: 1) What are the overall impacts of academic probation interventions on the academic success strategies and behaviors of students on academic probation? and 2) Which intervention(s) have the most significant impact on the academic success strategies and behaviors of students on academic probation? Using an experimental within-subjects design, this study investigated the impact of three support interventions: an academic success course, academic coaching, and workshops.

 

RESULTS AND IMPLICATIONS

Initial results showed increases in positive academic success behaviors and strategies for all three interventions, however academic coaching interventions saw higher gains in academic success strategies and behaviors than students enrolled in an academic success course or students assigned to workshops. While research has mostly focused on impacts academic success courses have on supporting students on academic probation/reinstatement, this study suggests that research should begin exploring additional methods of support that may ultimately be more constructive to this special population.

 

Exploring and Quantifying Unsystematic Risk in US Hotel REITs

Exploring and Quantifying Unsystematic Risk in US Hotel REITs

Primary Author: Hongwei Zhao

Faculty Sponsor: Ming-Hsiang Chen

 

Primary College/Unit: Carson College of Business

Category: Business, Communication, and Politial Sciences

Campus: Pullman

 

Abstract:

 

Principal topic:

Although Real Estate Investment Trusts (REITs) were originally conceptualized as mechanisms for individual investors to participate in institutional real estate, the ownership of REIT stocks has recently become dominated by institutional investors. Meanwhile, the hybrid nature of REITs is problematic for investors, particularly less diversified, individual investors who cannot mitigate unsystematic risk. This study included three sections intended to deconstruct unsystematic risk and enable investors to make more informed decisions in their investment portfolios.

Method:

Section one investigated unsystematic risk by selecting all publicly-traded company daily returns from January 2001 to December 2018 and running Fama-French model. Section two conducted a parallel analysis of unsystematic risk and institutional ownership. Section three investigated herding behavior in the Hotel REIT sector by parallel regression.

Results/implications:

Hotel REIT stocks have experienced wide variations in unsystematic risk between 14% and 92.5%. The trend toward institutional ownership of stocks is shown to have a significant negative impact on the levels of unsystematic risk. The implications remain to be identified as to whether higher levels of institutional ownership improve management efficiency and account for more monitoring power, in which price reflects more information and contains less individual specific risk. The unsystematic risk from REIT market returns is significantly lower than the one from the entire market returns, supporting that herding behavior in the Hotel REIT sector might “systematize” a portion of the unsystematic risk. Tracking investor sentiment may be one of factors explaining unsystematic risk for Hotel REITs.

 

Comparison of Microwave and Conventional Thermal Pasteurization of Frozen Green Beans

Comparison of Microwave and Conventional Thermal Pasteurization of Frozen Green Beans

Primary Author: ZHI QU

Faculty Sponsor: Juming Tang

 

Primary College/Unit: Agricultural, Human and Natural Resource Sciences

Category: Agricultural and Natural Resource Sciences

Campus: Pullman

 

Abstract:

 

PRINCIPAL TOPIC

Pasteurization is the process to eliminate pathogens and extend shelf life of food products. Consumer’s desire for high quality food and convenience has been a major driver for advancements of processing technologies. Microwave pasteurization can provide more rapid heating and better heating uniformity compared to conventional thermal pasteurization, thus holds potential to produce better quality vegetable products, such as fresh appearance and texture. The objective of this research was to study the influence of microwave and conventional thermal pasteurization on quality of green beans during storage at various cold chain temperatures.

METHOD

Thawed frozen green beans were vacuum sealed in 8 oz polymer trays, pasteurized in a pilot-scale 915 MHz Microwave Assisted Pasteurization System (MAPS) and conventional water bath (WB). The processed samples were stored at 10 and 2 °C. Color and chlorophyll content of green beans were quantified to elucidate the quality of the food.

RESULTS/IMPLICATIONS

For green beans, chlorophyll and green color suffered greater degradation when pasteurized using WB. During storage, under both temperatures, microwave pasteurized samples showed better color retention and higher chlorophyll content. And, microwave pasteurized green beans can be preserved for a longer time at 2°C (100 days) than WB heated one (80 days) with no package swelling observed. This implicates that microwave pasteurization might be a potential alternative to produce safe, high-quality vegetable products and preserve the quality during storage.