Life Sciences Commons^™

Hyperhomocysteinemia-Induced Gene Expression Changes In The Cell Types Of The Brain, Erica M. Weekman, Abigail E. Woolums, Tiffany L. Sudduth, Donna M. Wilcock

Sanders-Brown Center on Aging Faculty Publications

High plasma levels of homocysteine, termed hyperhomocysteinemia, are a risk factor for vascular cognitive impairment and dementia, which is the second leading cause of dementia. While hyperhomocysteinemia induces microhemorrhages and cognitive decline in mice, the specific effect of hyperhomocysteinemia on each cell type remains unknown. We took separate cultures of astrocytes, microglia, endothelial cells, and neuronal cells and treated each with moderate levels of homocysteine for 24, 48, 72, and 96 hr. We then determined the gene expression changes for cell-specific markers and neuroinflammatory markers including the matrix metalloproteinase 9 system. Astrocytes had decreased levels of several astrocytic end feet …

Physical Aggressiveness And Gray Matter Deficits In Ventromedial Prefrontal Cortex, David S. Chester, Donald R. Lynam, Richard Milich, C. Nathan Dewall

Psychology Faculty Publications

What causes individuals to hurt others? Since the famous case of Phineas Gage, lesions of the ventromedial prefrontal cortex (VMPFC) have been reliably linked to physically aggressive behavior. However, it is unclear whether naturally-occurring deficits in VMPFC, among normal individuals, might have widespread consequences for aggression. Using voxel based morphometry, we regressed gray matter density from the brains of 138 normal female and male adults onto their dispositional levels of physical aggression, verbal aggression, and sex, simultaneously. Physical, but not verbal, aggression was associated with reduced gray matter volume in the VMPFC and to a lesser extent, frontopolar cortex. Participants …

Influence Of Dietary Salt Knowledge, Perceptions, And Beliefs On Consumption Choices After Stroke In Uganda, Martin N. Kaddumukasa, Elly Katabira, Martha Sajatovic, Svetlana Pundik, Mark Kaddumukasa, Larry B. Goldstein

Neurology Faculty Publications

Background

Previous research on Uganda's poststroke population revealed that their level of dietary salt knowledge did not lead to healthier consumption choices.

Purpose

Identify barriers and motivators for healthy dietary behaviors and evaluate the understanding of widely accepted salt regulation mechanisms among poststroke patients in Uganda.

Methods

Convergent parallel mixed methods triangulation design comprised a cross-sectional survey (n = 81) and 8 focus group discussions with 7-10 poststroke participants in each group. We assessed participant characteristics and obtained insights into their salt consumption attitudes, perceptions, and knowledge. Qualitative responses were analyzed using an inductive approach with thematic analytic procedures. Relationships …

Language And Socioeconomics Predict Geographic Variation In Peer Review Outcomes At An Ecology Journal, C. Sean Burns, Charles W. Fox

Information Science Faculty Publications

Papers submitted by scientists located in western nations generally fare better in the peer review process than do papers submitted by scientists from elsewhere. This paper examines geographic variation in peer review outcomes (whether a manuscript is sent for review, review scores obtained, and final decisions by editors) for 3529 submissions over a 4.5 year period at the journal Functional Ecology. In particular, we test whether geographic variation in language and socioeconomics are adequate to explain most or are all of this variation. There was no relationship between the geographic regions of handling editors and the decisions to send …

Psychosocial Functioning And The Cortisol Awakening Response: Meta-Analysis, P-Curve Analysis, And Evaluation Of The Evidential Value In Existing Studies, Ian Andres Boggero, Camelia E. Hostinar, Eric A. Haak, Michael L. M. Murphy, Suzanne C. Segerstrom

Psychology Faculty Publications

Cortisol levels rise immediately after awakening and peak approximately 30-45 minutes thereafter. Psychosocial functioning influences this cortisol awakening response (CAR), but there is considerable heterogeneity in the literature. The current study used p-curve and metaanalysis on 709 findings from 212 studies to test the evidential value and estimate effect sizes of four sets of findings: those associating worse psychosocial functioning with higher or lower cortisol increase relative to the waking period (CARi) and to the output of the waking period (AUCw). All four sets of findings demonstrated evidential value. Psychosocial predictors explained 1%-3.6% of variance in CARi and AUCw …

Age Drives Distortion Of Brain Metabolic, Vascular And Cognitive Functions, And The Gut Microbiome, Jared D. Hoffman, Ishita Parikh, Stefan J. Green, George Chlipala, Robert P. Mohney, Mignon Keaton, Bjoern Bauer, Anika M. S. Hartz, Ai-Ling Lin

Sanders-Brown Center on Aging Faculty Publications

Advancing age is the top risk factor for the development of neurodegenerative disorders, including Alzheimer’s disease (AD). However, the contribution of aging processes to AD etiology remains unclear. Emerging evidence shows that reduced brain metabolic and vascular functions occur decades before the onset of cognitive impairments, and these reductions are highly associated with low-grade, chronic inflammation developed in the brain over time. Interestingly, recent findings suggest that the gut microbiota may also play a critical role in modulating immune responses in the brain via the brain-gut axis. In this study, our goal was to identify associations between deleterious changes in …

Preventing Horse-Related Injuries By Watching Out For Other Humans, William R. Gombeski Jr., Fernanda C. Camargo, Holly Wiemers, Connie Jehlik, Polly Haselton Barger, James Mead

Animal and Food Sciences Faculty Publications

The more one rides or handles horses, the more likely one is to have a horse-related injury. These injuries are caused by many factors, including those generated by other riders, handlers or spectators. An analysis of 266 cases of injured equestrians showed that 16% of those injuries were caused by other humans. A panel of horse riding safety experts felt 63% were preventable, and the injured individuals themselves felt 51% were preventable. The study findings suggest that increased awareness of the role others play in causing horse-related injuries and increased education about common people-caused injuries could reduce the number of …

Interleukin-6 (Il-6) Rs1800796 And Cyclin Dependent Kinase Inhibitor (Cdkn2a/Cdkn2b) Rs2383207 Are Associated With Ischemic Stroke In Indigenous West African Men, Rufus Akinyemi, Donna K. Arnett, Hemant K. Tiwari, Bruce Ovbiagele, Fred Sarfo, Vinodh Srinivasasainagendra, Marguerite Ryan Irvin, Abiodun Adeoye, Rodney T. Perry, Albert Akpalu, Carolyn Jenkins, Lukman Owolabi, Reginald Obiako, Kolawole Wahab, Emmanuel Sanya, Morenikeji Komolafe, Michael Fawale, Philip Adebayo, Godwin Osaigbovo, Taofiki Sunmonu, Paul Olowoyo, Innocent Chukwuonye, Yahaya Obiabo, Onoja Akpa, Sylvia Melikam, Raelle Saulson, Raj Kalaria, Adesola Ogunniyi, Mayowa Owolabi

Epidemiology and Environmental Health Faculty Publications

Background—Inherited genetic variations offer a possible explanation for the observed peculiarities of stroke in sub – Saharan African populations. Interleukin–6 polymorphisms have been previously associated with ischemic stroke in some non-African populations.

Aim—Herein we investigated, for the first time, the association of genetic polymorphisms of IL-6 and CDKN2A- CDKN2B and other genes with ischemic stroke among indigenous West African participants in the Stroke Investigative Research and Education Network (SIREN) Study.

Methods—Twenty-three previously identified single nucleotide polymorphisms (SNPs) in 14 genes of relevance to the neurobiology of ischemic stroke were investigated. Logistic regression models adjusting for known …

Linking Kindling To Increased Glutamate Release In The Dentate Gyrus Of The Hippocampus Through The Stxbp5/Tomosyn-1 Gene, Seth R. Batten, Elena A. Matveeva, Sidney W. Whiteheart, Thomas C. Vanaman, Greg A. Gerhardt, John T. Slevin

Psychology Faculty Publications

Introduction: In kindling, repeated electrical stimulation of certain brain areas causes progressive and permanent intensification of epileptiform activity resulting in generalized seizures. We focused on the role(s) of glutamate and a negative regulator of glutamate release, STXBP5/tomosyn-1, in kindling.

Methods: Stimulating electrodes were implanted in the amygdala and progression to two successive Racine stage 5 seizures was measured in wild-type and STXBP5/tomosyn-1^−/− (Tom^−/−) animals. Glutamate release measurements were performed in distinct brain regions using a glutamate-selective microelectrode array (MEA).

Results: Naïve Tom^−/− mice had significant increases in KCl-evoked glutamate release compared to naïve wild type as …

Pro-Angiogenesis Therapy And Aging: A Mini-Review, Charles T. Ambrose

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Apart from major illnesses and chronic afflictions, the elderly experience lesser ailments, such as muscle weakness, cold intolerance, and transient memory lapses. Physical signs in the aged include wrinkled skin and the slow healing of skin abrasions. These ailments and signs are grouped together because they may be due in part to an age-linked, waning microcirculation. A reduced capillary density (CD) throughout the body of aged people and animals has been reported in over 40 papers. The reduced CD is due in turn to declining levels of angiogenic growth factors (AGFs) throughout the body during old age, as documented in …

Impact Of Home Visit Capacity On Genetic Association Studies Of Late-Onset Alzheimer's Disease, David W. Fardo, Laura E. Gibbons, Shubhabrata Mukherjee, M. Maria Glymour, Wayne Mccormick, Susan M. Mccurry, James D. Bowen, Eric B. Larson, Paul K. Crane

Biostatistics Faculty Publications

INTRODUCTION—Findings for genetic correlates of late-onset Alzheimer's disease (LOAD) in studies that rely solely on clinic visits may differ from those with capacity to follow participants unable to attend clinic visits.

METHODS—We evaluated previously identified LOAD-risk single nucleotide variants in the prospective Adult Changes in Thought study, comparing hazard ratios (HRs) estimated using the full data set of both in-home and clinic visits (n = 1697) to HRs estimated using only data that were obtained from clinic visits (n = 1308). Models were adjusted for age, sex, principal components to account for ancestry, and additional health indicators.

RESULTS …

Impulsive Personality Dimensions Are Associated With Altered Behavioral Performance And Neural Responses In The Monetary Incentive Delay Task, Ruolei Gu, Yang Jiang, Seth Kiser, Chelsea L. Black, Lucas S. Broster, Yue-Jia Luo, Thomas H. Kelly

Behavioral Science Faculty Publications

Individual differences in dimensions of impulsivity personality including disinhibition and sensation seeking modulate approach responses to reinforcing stimuli, such as drugs and money. The current study examined the effects of monetary incentive on both behavioral performance and electrophysiological activity among individuals varying in disinhibition and sensation seeking. The monetary incentive delay (MID) task was completed under electroencephalogram (EEG) recording. Behavioral data showed that higher disinhibition and sensation-seeking were associated with lower performance accuracy. Event-related potential (ERP) data showed that high reinforcement cues elicited a larger late positive component (LPC) than other conditions among high disinhibition participants, indicating its strong emotional …

Using Neonatal Skin To Study The Developmental Programming Of Aging, Leryn J. Reynolds, Brett J. Dickens, Benjamin B. Green, Carmen J. Marsit, Kevin J. Pearson

Pharmacology and Nutritional Sciences Faculty Publications

Numerous studies have examined how both negative and positive maternal exposures (environmental contaminants, nutrition, exercise, etc.) impact offspring risk for age-associated diseases such as obesity, type 2 diabetes, hypertension, and others. The purpose of this study was to introduce the foreskin as a novel model to examine developmental programming in human neonates, particularly in regard to adipogenesis and insulin receptor signaling, major contributors to age-associated diseases such as obesity and diabetes. Neonatal foreskin was collected following circumcision and primary dermal fibroblasts were isolated to perform adipocyte differentiation and insulin stimulation experiments. Human neonatal foreskin primary fibroblasts take up lipid when …

Stimulus-Selectivity Of Drug Purchase Tasks: A Preliminary Study Evaluating Alcohol And Cigarette Demand, Justin Charles Strickland, William W. Stoops

Psychology Faculty Publications

The use of drug purchase tasks to measure drug demand in human behavioral pharmacology and addiction research has proliferated in recent years. Few studies have systematically evaluated the stimulus selectivity of drug purchase tasks to demonstrate that demand metrics are specific to valuation of or demand for the commodity under study. Stimulus selectivity is broadly defined for this purpose as a condition under which a specific stimulus input or target (e.g., alcohol, cigarettes) is the primary determinant of behavior (e.g., demand). The overall goal of the present study was to evaluate the stimulus selectivity of drug purchase tasks. Participants were …

The Effects Of Nicotine In The Neonatal Quinpirole Rodent Model Of Psychosis: Neural Plasticity Mechanisms And Nicotinic Receptor Changes, Daniel J. Peterson, W. Drew Gill, John M. Dose, Donald B. Hoover, James R. Pauly, Elizabeth D. Cummins, Katherine C. Burgess, Russell W. Brown

Pharmaceutical Sciences Faculty Publications

Neonatal quinpirole (NQ) treatment to rats increases dopamine D2 receptor sensitivity persistent throughout the animal’s lifetime. In Experiment 1, we analyzed the role of α7 and α4β2 nicotinic receptors (nAChRs) in nicotine behavioral sensitization and on the brain-derived neurotrophic factor (BDNF) response to nicotine in NQ- and neonatally saline (NS)-treated rats. In Experiment 2, we analyzed changes in α7 and α4β2 nAChR density in the nucleus accumbens (NAcc) and dorsal striatum in NQ and NS animals sensitized to nicotine. Male and female Sprague-Dawley rats were neonatally treated with quinpirole (1 mg/kg) or saline from postnatal days (P)1–21. Animals were given …

Single-Trait And Multi-Trait Genome-Wide Association Analyses Identify Novel Loci For Blood Pressure In African-Ancestry Populations, Jingjing Liang, Thu H. Le, Digna R. Velez Edwards, Bamidele O. Tayo, Kyle J. Gaulton, Jennifer A. Smith, Yingchang Lu, Richard A. Jensen, Guanjie Chen, Lisa R. Yanek, Karen Schwander, Salman M. Tajuddin, Tamar Sofer, Wonji Kim, James Kayima, Colin A. Mckenzie, Ervin Fox, Michael A. Nalls, J. Hunter Young, Yan V. Sun, Jacqueline M. Lane, Sylvia Cechova, Jie Zhou, Hua Tang, Myriam Fornage, Solomon K. Musani, Heming Wang, Juyoung Lee, Adebowale Adeyemo, Albert W. Dreisbach, Donna K. Arnett

Epidemiology and Environmental Health Faculty Publications

Hypertension is a leading cause of global disease, mortality, and disability. While individuals of African descent suffer a disproportionate burden of hypertension and its complications, they have been underrepresented in genetic studies. To identify novel susceptibility loci for blood pressure and hypertension in people of African ancestry, we performed both single and multiple-trait genome-wide association analyses. We analyzed 21 genome-wide association studies comprised of 31,968 individuals of African ancestry, and validated our results with additional 54,395 individuals from multi-ethnic studies. These analyses identified nine loci with eleven independent variants which reached genome-wide significance (P < 1.25×10⁻⁸) for either systolic and …

Discovery And Fine-Mapping Of Adiposity Loci Using High Density Imputation Of Genome-Wide Association Studies In Individuals Of African Ancestry: African Ancestry Anthropometry Genetics Consortium, Maggie C. Y. Ng, Mariaelisa Graff, Yingchang Lu, Anne E. Justice, Poorva Mudgal, Ching-Ti Liu, Kristin Young, Lisa R. Yanek, Mary F. Feitosa, Mary K. Wojczynski, Kristin Rand, Jennifer A. Brody, Brian E. Cade, Latchezar Dimitrov, Qing Duan, Xiuqing Guo, Leslie A. Lange, Michael A. Nalls, Hayrettin Okut, Salman M. Tajuddin, Bamidele O. Tayo, Sailaja Vedantam, Jonathan P. Bradfield, Guanjie Chen, Wei-Min Chen, Alessandra Chesi, Marguerite R. Irvin, Badri Padhukasahasram, Jennifer A. Smith, Wei Zheng, Donna K. Arnett

Epidemiology and Environmental Health Faculty Publications

Genome-wide association studies (GWAS) have identified > 300 loci associated with measures of adiposity including body mass index (BMI) and waist-to-hip ratio (adjusted for BMI, WHR_adjBMI), but few have been identified through screening of the African ancestry genomes. We performed large scale meta-analyses and replications in up to 52,895 individuals for BMI and up to 23,095 individuals for WHR_adjBMI from the African Ancestry Anthropometry Genetics Consortium (AAAGC) using 1000 Genomes phase 1 imputed GWAS to improve coverage of both common and low frequency variants in the low linkage disequilibrium African ancestry genomes. In the sex-combined analyses, we identified …

Retention Of Normal Glia Function By An Isoform-Selective Protein Kinase Inhibitor Drug Candidate That Modulates Cytokine Production And Cognitive Outcomes, Zhengqiu Zhou, Adam D. Bachstetter, Claudia B. Späni, Saktimayee M. Roy, D. Martin Watterson, Linda J. Van Eldik

Sanders-Brown Center on Aging Faculty Publications

Background: Brain p38α mitogen-activated protein kinase (MAPK), a potential therapeutic target for cognitive dysfunction based on the neuroinflammation-synaptic dysfunction cycle of pathophysiology progression, offers an innovative pharmacological strategy via inhibiting the same activated target in both glia and neurons, thereby enhancing the possibility for efficacy. The highly selective, brain-penetrant p38αMAPK inhibitor MW150 attenuates cognitive dysfunction in two distinct Alzheimer's disease (AD)-relevant models and avoids the problems encountered with previous mixed-kinase inhibitor drug candidates. Therefore, it is essential that the glial effects of this CNS-active kinase inhibitor be addressed in order to anticipate future use in clinical investigations.

Methods: …

Csf Protein Changes Associated With Hippocampal Sclerosis Risk Gene Variants Highlight Impact Of Grn/Pgrn, David W. Fardo, Yuriko Katsumata, John S. K. Kauwe, Yuetiva Deming, Oscar Harari, Carlos Cruchaga, Alzheimer’S Disease Neuroimaging Initiative, Peter T. Nelson

Sanders-Brown Center on Aging Faculty Publications

Objective—Hippocampal sclerosis of aging (HS-Aging) is a common cause of dementia in older adults. We tested the variability in cerebrospinal fluid (CSF) proteins associated with previously identified HS-Aging risk single nucleotide polymorphisms (SNPs).

Methods—Alzheimer’s Disease Neuroimaging Initiative cohort (ADNI; n=237) data, combining both multiplexed proteomics CSF and genotype data, were used to assess the association between CSF analytes and risk SNPs in four genes (SNPs): GRN (rs5848), TMEM106B (rs1990622), ABCC9 (rs704180), and KCNMB2 (rs9637454). For controls, non-HS-Aging SNPs in APOE (rs429358/rs7412) and MAPT (rs8070723) were also analyzed against Aβ1-42 and total tau CSF analytes.

Results—The GRN risk …

A Prototypical First-Generation Electronic Cigarette Does Not Reduce Reports Of Tobacco Urges Or Withdrawal Symptoms Among Cigarette Smokers, Arit M. Harvanko, Catherine A. Martin, Richard J. Kryscio, William W. Stoops, Joshua A. Lile, Thomas H. Kelly

Psychology Faculty Publications

It is unknown whether first-generation electronic cigarettes reduce smoking urges and withdrawal symptoms following a 24 h deprivation period. This study tested whether a first-generation electronic cigarette reduces smoking urges and withdrawal symptoms in cigarette smokers. Following 24 h of tobacco deprivation, using a within-subjects design, eight nontreatment seeking tobacco cigarette smokers (3 females) administered 10 puffs from a conventional cigarette or a first-generation electronic cigarette containing liquid with 0, 8 or 16 mg/ml nicotine. Conventional cigarettes ameliorated smoking urges and electronic cigarettes did not, regardless of nicotine concentration. First-generation electronic cigarettes may not effectively substitute for conventional cigarettes in …

Impacts Of Corn Price And Imported Beef Price On Domestic Beef Price In South Korea, Gwanseon Kim, Tyler Mark

Agricultural Economics Faculty Publications

South Korea is one of the largest beef importing countries in the world. Australia, USA, and New Zealand provide the majority of beef they import. The objective of this study is to evaluate the price relationship of Korean cattle and corn, prices of the imported beef and corn, and prices of Korean cattle and imported beef. We examine threshold points using threshold vector autoregressive (TVAR) model by assuming the presence of nonlinearity. We find that there are two thresholds in Australian beef price with first difference data. This study finds that the current Korean beef price is positively affected by …

Tuning Up The Old Brain With New Tricks: Attention Training Via Neurofeedback, Yang Jiang, Reza Abiri, Xiaopeng Zhao

Sanders-Brown Center on Aging Faculty Publications

Neurofeedback (NF) is a form of biofeedback that uses real-time (RT) modulation of brain activity to enhance brain function and behavioral performance. Recent advances in Brain-Computer Interfaces (BCI) and cognitive training (CT) have provided new tools and evidence that NF improves cognitive functions, such as attention and working memory (WM), beyond what is provided by traditional CT. More published studies have demonstrated the efficacy of NF, particularly for treating attention deficit hyperactivity disorder (ADHD) in children. In contrast, there have been fewer studies done in older adults with or without cognitive impairment, with some notable exceptions. The focus of this …

Recruitment Of Reviewers Is Becoming Harder At Some Journals: A Test Of The Influence Of Reviewer Fatigue At Six Journals In Ecology And Evolution, Charles W. Fox, Arianne Y. K. Albert, Timothy H. Vines

Entomology Faculty Publications

Background: It is commonly reported by editors that it has become harder to recruit reviewers for peer review and that this is because individuals are being asked to review too often and are experiencing reviewer fatigue. However, evidence supporting these arguments is largely anecdotal.

Main body: We examine responses of individuals to review invitations for six journals in ecology and evolution. The proportion of invitations that lead to a submitted review has been decreasing steadily over 13 years (2003–2015) for four of the six journals examined, with a cumulative effect that has been quite substantial (average decline from 56% of …

Cytomegalovirus Serostatus, Inflammation, And Antibody Response To Influenza Vaccination In Older Adults: The Moderating Effect Of Beta Blockade, Rebecca G. Reed, Richard N. Greenberg, Suzanne C. Segerstrom

Psychology Faculty Publications

Cytomegalovirus (CMV) has been implicated as a factor in immunosenescence, including poor antibody response to vaccination and higher immune activation and inflammation. Some people may be more or less vulnerable to the negative effects of CMV. The present investigation tested the effects of beta-blocker use and chronological age on the associations between CMV and immunity in adults aged 60–91 (N=98; 69% CMV seropositive) who were administered the trivalent influenza vaccine for up to 5 years. Peak antibody response, corrected for baseline, and spring (persistent) antibody response, corrected for peak, were assessed, as well as beta-2 microglobulin (β2μ) and interleukin-6 (IL-6). …

Kentucky Forestry Economic Contribution Report 2016, Jeff Stringer, Billy Thomas, Bobby Ammerman, Thomas Ochuodho, Alison Davis

Kentucky Forestry Economic Impact Reports

Forests play a pivotal role in Kentucky’s economy and in the lives of the citizens of our state. Forests are the single most dominant land type, covering nearly one-half of the state, providing a significant range of both economic and non-economic benefits to the Commonwealth. The majority of the economic contribution is derived from the harvesting of timber and processing of the wood resource. Analysis of Kentucky’s forest and wood industries in 2016 indicated an estimated direct economic contribution of $9 billion (down one percent from 2015). These industries employed over 27,700 individuals. Total economic contributions in 2016 were estimated …

Riding Through Life: A Lifespan Study Of The Attitudes, Behaviors, And Areas Of Educational Opportunity For Female Equestrians Toward Bra Use And Health Outcomes When Engaged In Equestrian Sports, Karin Pekarchik

Theses and Dissertations--Community & Leadership Development

Equestrian sport is a popular exercise choice for females of all ages, although the links between this exercise choice, health outcomes, and risk to health have not been thoroughly examined. These issues are of particular interest because the female equestrian has the opportunity to ride and/or compete for decades, from early to very late in life, covering almost the full sequence of the female lifespan. Equestrian sports provide physical activity through riding and caring for the horse, and promote positive mental outcomes through tangible practices, such as engaging in physical activity and hard work, goal-setting, acquisition of skills, and participation …

Three Essays On Food Safety Regulations And International Trade Of Agricultural Products, Jun Ho Seok

Theses and Dissertations--Agricultural Economics

This dissertation investigates food safety regulations and international trade of agricultural products dividing into three aspects: the signalling effect from U.S. strict food safety regulations on U.S. vegetable exports, political determinants of sanitary and photosanitary non-tariff barriers, and the impact of trade barriers on employment in developing countries. In chapter 2, we investigate the impact of high U.S. maximum residue limit (MRL) standards on U.S vegetable exports to 102 countries utilizing the hierarchical model. MRL, which is one of non-tariff barriers with respect to food safety, is applied to home and foreign countries at the same time. Thus, firms in …