Size Effects In Mesoscale Mechanical Testing Of Snow

Thesis (Ph.D.) University of Alaska Fairbanks, 2013Snow is a naturally-occurring, heterogeneous material whose interactions with humans make it desirable for analysis as a geotechnical engineering material. In this study, clean, undisturbed, natural snows of two common types were collected in and around Fairbanks, Alaska and subjected to laboratory testing, and the results were compiled and analyzed. Three types of tests--flat pin indentation, unconfined compression, and cone penetration--were carried out while varying size parameters, and size effects were observed and studied. From flat-pin indentation testing, it was observed that first peak indentation strength initially fell exponentially with increasing indenter cross-sectional area, with the exponent averaging 0.84. Furthermore, the strength eventually rose to a plateau value, and the compression strength of snow could be calculated from this plateau value. This plateau, too, initially depended exponentially on the pin cross-sectional area for smaller pins. From unconfined compression testing, it was observed that as cross-sectional area of a flat pin indenter increased, plateau strength eventually reached that value found from unconfined compression testing. Furthermore, initial strength, plateau strength, and energy absorption density all increased linearly with increasing aspect ratio. From cone penetration testing, it was found that empirical values of snow strength may be obtained on both a micromechanical and macromechanical scale using cone penetration. Size effects, were also observed--smaller cone diameters and larger cone included angles yielded larger values for apparent snow strength. Some of the mechanisms behind all of these size effects are explainable from theory; others must be regarded for now as empirical in nature. In both cases, the results are quite reliable descriptors for a natural material, and may be safely interpolated from

Characteristics and Risk of Microgrid Outages from a Complex Systems Point of View

Cordova is a town of approximately 2,000 people located on the southern coast of Alaska. A power grid for a town this size, with a large seasonal fishing economy, is considered a moderate to large sized microgrid in terms of power produced. Understanding the vulnerabilities and risks of failures in such a grid is important for planning and operations. Investigating these characteristics in the context of complex system dynamics is a novel approach. The analysis of Cordova’s microgrid is a case study relevant to a large class of microgrid communities. We analyze the outage data based on size, cause characteristics and load demand on the system and find long time correlations and power laws in the failure size distributions. Finally we apply a risk metric to give a single numerical value to the risk of an outage occurring during certain time periods and under certain conditions

Anesthesia Services in the Time of COVID

Our hospital is a 400-bed Level-1 trauma center with 78 ICU beds serving the greater Louisville metropolitan area. The COVID-19 pandemic forced our hospital to re-evaluate our core business operations and to develop a coherent response to a fluid situation. Between March 15 and May 15, 2020, the University of Louisville Hospital admitted more than 100 COVID-19 inpatients, approximately 30 were admitted to the intensive care unit (ICU) and most required endotracheal intubation. The following review describes our Department of Anesthesiology & Perioperative Medicine foci, actions and rationale during the COVID-19 pandemic. While we hope not to experience another pandemic in the near future, this review may be a helpful starting point for preparing for future respiratory spread pandemics

Do bank loans and local amenities explain Chinese urban house prices?

Using Chinese city-level data from 1999 to 2012 and considering geological, environmental, and social diversity, this study suggests that credit plays a significant role in driving up house prices after the Great Recession, whereas property prices only influence bank lending before 2008. Besides, local amenities such as higher education, green infrastructure, healthcare, and climate also positively affect house prices. Moreover, the impacts of bank loans and amenities on housing prices are interacted rather than isolated

Does social contact lessen perceived cultural distance? Evidence from tourist–host social contact

2016-2017 > Academic research: refereed > Publication in refereed journal201804_a bcm

Hai Di Lao Hot Pot: From Employee Stimulation to Service Innovation

The management of Chinese restaurant chains has for some time followed the western model while accommodating Chinese customers. The new Hai Di Lao Hot Pot Restaurant chain has established its own management style, pioneering chain catering management to help the Chinese restaurant industry establish a professional image, explore a local management model, and maintain high standards of food safety. The objectives of this case study are to introduce the Hai Di Lao managerial strategy, investigate the secrets of its success from a human resources management perspective, to explore its innovative service, and to assess why it has inspired both marketers and the catering industry. The results show that human resources management can change employees’ behavior and emotional states by addressing a wide variety of needs. In addition, attention to service quality can improve customer satisfaction and retention

Neighbourhood environment and dementia in older people from high-, middle- and low-income countries: results from two population-based cohort studies

Abstract: Background: A growing number of studies have explored how features of the neighbourhood environment can be related to cognitive health in later life. Yet few have focused on low- and middle-income countries and compared the results across different settings. The aim of this study is to investigate the cross-sectional associations between neighbourhood amenities and dementia in older people from high-, middle- and low-income countries. Methods: This study was based on two population-based cohort studies of people aged≥65: the Cognitive Function and Ageing Study II (CFAS II) in UK (N = 4955) and a subset of the 10/66 study in China, Dominican Republic and Mexico (N = 3386). In both cohorts, dementia was assessed using the Geriatric Mental State−Automated Geriatric Examination for Computer Assisted Taxonomy (GMS-AGECAT) algorithm. The 10/66 dementia diagnostic algorithm was also used as an additional criterion in the 10/66 study. Publicly accessible databases, Google Maps and Open Street Map, were used to obtain geographic information system data on distance to neighbourhood amenities, including lifestyle (cafés, libraries, movie theatres, parks), daily life (post offices, convenience stores), healthcare (hospitals, pharmacies) and percentages of local green and blue spaces within 400 and 800 m of participants’ residences. Multilevel logistic regression was used to investigate the associations between these environmental features and dementia adjusting for sociodemographic factors and self-rated health. Results: Living far from daily life amenities was associated with higher odds of dementia in both CFAS II (1.47; 95% CI: 0.96, 2.24) and the 10/66 study (1.53; 95% CI: 1.15, 2.04), while living far from lifestyle (1.50; 95% CI: 1.13, 1.99) and healthcare amenities (1.32; 95% CI: 0.93, 1.87) was associated with higher odds of dementia only in the 10/66 study. A high availability of local green and blue spaces was not associated with dementia in either cohort yet living far from public parks was associated with lower odds of dementia in CFAS II (0.64; 95% CI: 0.41, 1.00). Conclusions: The different relationships across cohorts may indicate a varying role for local amenities in diverse settings. Future research may investigate mechanisms related to these differences and social, cultural and historical influences on the interaction between neighbourhood amenities and older people

Wheat amylase/trypsin inhibitors (ATIs) : occurrence, function and health aspects

Amylase/trypsin inhibitors (ATIs) are widely consumed in cereal-based foods and have been implicated in adverse reactions to wheat exposure, such as respiratory and food allergy, and intestinal responses associated with coeliac disease and non-coeliac wheat sensitivity. ATIs occur in multiple isoforms which differ in the amounts present in different types of wheat (including ancient and modern ones). Measuring ATIs and their isoforms is an analytical challenge as is their isolation for use in studies addressing their potential effects on the human body. ATI isoforms differ in their spectrum of bioactive effects in the human gastrointestinal (GI), which may include enzyme inhibition, inflammation and immune responses and of which much is not known. Similarly, although modifications during food processing (exposure to heat, moisture, salt, acid, fermentation) may affect their structure and activity as shown in vitro, it is important to relate these changes to effects that may present in the GI tract. Finally, much of our knowledge of their potential biological effects is based on studies in vitro and in animal models. Validation by human studies using processed foods as commonly consumed is warranted. We conclude that more detailed understanding of these factors may allow the effects of ATIs on human health to be better understood and when possible, to be ameliorated, for example by innovative food processing. We therefore review in short our current knowledge of these proteins, focusing on features which relate to their biological activity and identifying gaps in our knowledge and research priorities.Peer reviewe

Contribution of adipocyte Na/K-ATPase α1/CD36 signaling induced exosome secretion in response to oxidized LDL

IntroductionAdipose tissue constantly secretes adipokines and extracellular vesicles including exosomes to crosstalk with distinct tissues and organs for whole-body homeostasis. However, dysfunctional adipose tissue under chronic inflammatory conditions such as obesity, atherosclerosis, and diabetes shows pro-inflammatory phenotypes accompanied by oxidative stress and abnormal secretion. Nevertheless, molecular mechanisms of how adipocytes are stimulated to secrete exosomes under those conditions remain poorly understood.MethodsMouse and human in vitro cell culture models were used for performing various cellular and molecular studies on adipocytes and macrophages. Statistical analysis was performed using Student's t-test (two-tailed, unpaired, and equal variance) for comparisons between two groups or ANOVA followed by Bonferroni's multiple comparison test for comparison among more than two groups.Results and discussionIn this work, we report that CD36, a scavenger receptor for oxidized LDL, formed a signaling complex with another membrane signal transducer Na/K-ATPase in adipocytes. The atherogenic oxidized LDL induced a pro-inflammatory response in in vitro differentiated mouse and human adipocytes and also stimulated the cells to secrete more exosomes. This was largely blocked by either CD36 knockdown using siRNA or pNaKtide, a peptide inhibitor of Na/K-ATPase signaling. These results showed a critical role of the CD36/Na/K-ATPase signaling complex in oxidized LDL-induced adipocyte exosome secretion. Moreover, by co-incubation of adipocyte-derived exosomes with macrophages, we demonstrated that oxidized LDL-induced adipocyte-derived exosomes promoted pro-atherogenic phenotypes in macrophages, including CD36 upregulation, IL-6 secretion, metabolic switch to glycolysis, and mitochondrial ROS production. Altogether, we show here a novel mechanism through which adipocytes increase exosome secretion in response to oxidized LDL and that the secreted exosomes can crosstalk with macrophages, which may contribute to atherogenesis

Major Functional Transcriptome of an Inferred Center Regulator of an ER(−) Breast Cancer Model System

We aimed to find clinically relevant gene activities ruled by the signal transducer and activator of transcription 3 (STAT3) proteins in an ER(−) breast cancer population via network approach. STAT3 is negatively associated with both lymph nodal category and stage. MYC is a component of STAT3 network. MYC and STAT3 may co-regulate gene expressions for Warburg effect, stem cell like phenotype, cell proliferation and angiogenesis. We identified a STAT3 network in silico showing its ability in predicting its target gene expressions primarily for specific tumor subtype, tumor progression, treatment options and prognostic features. The aberrant expressions of MYC and STAT3 are enriched in triple negatives (TN). They promote histological grade, vascularity, metastasis and tumor anti-apoptotic activities. VEGFA, STAT3, FOXM1 and METAP2 are druggable targets. High levels of METAP2, MMP7, IGF2 and IGF2R are unfavorable prognostic factors. STAT3 is an inferred center regulator at early cancer development predominantly in TN