Z Deviation Based Demand Side Control to Reduce FIDVR

Accurate load modeling is key to depicting realistic system behavior in power system simulations. In the past, the use of static load models resulted in overly optimistic results, which led to unforeseen outages and issues following faults. One common cause of these types of unforeseen issues is Fault Induced Delayed Voltage Recovery (FIDVR). FIDVR occurs due to the stalling of single-phase residential air conditioners (A/C), and causes the voltage recovery after a fault to be slow. Improvements in load models over time have resulted in the capability of modeling load dynamics, and therefore better FIDVR. A composite load model based on real world composition data is applied to a 179 bus system representing the WECC system. Then through mathematical derivation and fault analysis, a method, Z Deviation, is proposed as a way to identify the occurrence of FIDVR. Z Deviation is then implemented in a control scheme used to improve voltage recovery following FIDVR, and its effectiveness is compared to a device level protection scheme

Managing Student Bullying of Professors in Higher Educational Institutions

Workplace bullying has affected more than 60 million workers in the United States. The specific problem was a lack of information about academic contrapower harassment on conflict management in higher educational institutions. The purpose of this qualitative multiple case study was to explore how administrators in higher educational institutions addressed student bullying of professors when reported by professors to administrators. The research question was to explore what conflict management strategies were used by school administrators in higher educational institutions to address targeted professors’ reports of student bullying. The conceptual framework for the study included academic contrapower harassment, student entitlement, and student consumerism. Seventeen professors who were targets of student bullying through social media participated. Semistructured interviews data were collected and analyzed by establishing three hierarchical coding nodes matching the interview questions contributing to thematic data saturation and triangulation. Findings showed that school administrators primarily used investigations, appeasing students, and practicing avoidance to respond to targeted professors’ reports of student bullying. Fifteen professors viewed bullying by students being problematic in higher education. Recommendations for future research comprise interventions about academic contrapower harassment from the school administrators’ perspectives. The implications for positive social change may occur when administrators in higher educational institutions increase the awareness of academic contrapower harassment, promote human self-worth, and evaluate the effectiveness of school administrators’ conflict management strategies to address workplace bullying

Managing Student Bullying of Professors in Higher Educational Institutions

Workplace bullying has affected more than 60 million workers in the United States. The specific problem was a lack of information about academic contrapower harassment on conflict management in higher educational institutions. The purpose of this qualitative multiple case study was to explore how administrators in higher educational institutions addressed student bullying of professors when reported by professors to administrators. The research question was to explore what conflict management strategies were used by school administrators in higher educational institutions to address targeted professors’ reports of student bullying. The conceptual framework for the study included academic contrapower harassment, student entitlement, and student consumerism. Seventeen professors who were targets of student bullying through social media participated. Semistructured interviews data were collected and analyzed by establishing three hierarchical coding nodes matching the interview questions contributing to thematic data saturation and triangulation. Findings showed that school administrators primarily used investigations, appeasing students, and practicing avoidance to respond to targeted professors’ reports of student bullying. Fifteen professors viewed bullying by students being problematic in higher education. Recommendations for future research comprise interventions about academic contrapower harassment from the school administrators’ perspectives. The implications for positive social change may occur when administrators in higher educational institutions increase the awareness of academic contrapower harassment, promote human self-worth, and evaluate the effectiveness of school administrators’ conflict management strategies to address workplace bullying

I Just Want To Be Me, Authentically : Identity Shifting Among Racially and Ethnically Diverse Young Adults

Identity shifting represents a common but complex social, behavioral, and cognitive phenomenon. However, some forms of identity shifting originate in response to structural, institutional, and interpersonal marginalization enacted on lower status groups, such as people of color in the United States. The current study investigated ways young adults from diverse ethnic/racial groups discussed shifting to fit in with White Americans (a dominant group) in the United States and their own ethnic/racial group (a minoritized group) and elucidated self-reported motivations for shifting. Participants consisted of 764 young adults (ages = 18–23) recruited from two large public universities in the Southeast and Southwest regions of the United States. The majority of participants identified as Black/African American (41%), Asian/Asian American (27%), or Hispanic/Latinx (22%). Analysis of participants’ qualitative responses identified six types of shifts and two motivations for shifting. The shifts included: behavioral, linguistic, cognitive, physical, food, and affect. Motivations for shifting focused on avoiding risks and obtaining rewards. The discussion offers interpretation of the results and recommendations for future research on identity shifting

Bovine Model of Doxorubicin-Induced Cardiomyopathy

Left ventricular assist devices (LVADs) constitute a recent advance in heart failure (HF) therapeutics. As the rigorous experimental assessment of LVADs in HF requires large animal models, our objective was to develop a bovine model of cardiomyopathy. Male calves (n = 8) were used. Four animals received 1.2 mg/kg intravenous doxorubicin weekly for seven weeks and four separate animals were studied as controls. Doxorubicin-treated animals were followed with weekly echocardiography. Target LV dysfunction was defined as an ejection fraction ≤35%. Sixty days after initiating doxorubicin, a terminal study was performed to determine hemodynamic, histological, biochemical, and molecular parameters. All four doxorubicin-treated animals exhibited significant (P < 0.05) contractile dysfunction, with target LV dysfunction achieved in three animals. Doxorubicin-treated hearts exhibited significantly reduced coronary blood flow and interstitial fibrosis and significantly increased apoptosis and myocyte size. Gene expression of atrial natriuretic factor increased more than 3-fold. Plasma norepinephrine and epinephrine levels were significantly increased early and late during the development of cardiomyopathy, respectively. We conclude that sequential administration of intravenous doxorubicin in calves induces a cardiomyopathy with many phenotypic hallmarks of the failing human heart. This clinically-relevant model may be useful for testing pathophysiologic responses to LVADs in the context of HF

Collagen Type XIX Regulates Cardiac Extracellular Matrix Structure and Ventricular Function

The cardiac extracellular matrix plays essential roles in homeostasis and injury responses. Although the role of fibrillar collagens have been thoroughly documented, the functions of non-fibrillar collagen members remain underexplored. These include a distinct group of non-fibrillar collagens, termed, fibril-associated collagens with interrupted triple helices (FACITs). Recent reports of collagen type XIX (encoded by Col19a1) expression in adult heart and evidence of its enhanced expression in cardiac ischemia suggest important functions for this FACIT in cardiac ECM structure and function. Here, we examined the cellular source of collagen XIX in the adult murine heart and evaluated its involvement in ECM structure and ventricular function. Immunodetection of collagen XIX in fractionated cardiovascular cell lineages revealed fibroblasts and smooth muscle cells as the primary sources of collagen XIX in the heart. Based on echocardiographic and histologic analyses, Col19a1 null (Col19a1(N/N)) mice exhibited reduced systolic function, thinning of left ventricular walls, and increased cardiomyocyte cross-sectional areas—without gross changes in myocardial collagen content or basement membrane morphology. Col19a1(N/N) cardiac fibroblasts had augmented expression of several enzymes involved in the synthesis and stability of fibrillar collagens, including PLOD1 and LOX. Furthermore, second harmonic generation-imaged ECM derived from Col19a1(N/N) cardiac fibroblasts, and transmission electron micrographs of decellularized hearts from Col19a1(N/N) null animals, showed marked reductions in fibrillar collagen structural organization. Col19a1(N/N) mice also displayed enhanced phosphorylation of focal adhesion kinase (FAK), signifying de-repression of the FAK pathway—a critical mediator of cardiomyocyte hypertrophy. Collectively, we show that collagen XIX, which had a heretofore unknown role in the mammalian heart, participates in the regulation of cardiac structure and function—potentially through modulation of ECM fibrillar collagen structural organization. Further, these data suggest that this FACIT may modify ECM superstructure via acting at the level of the fibroblast to regulate their expression of collagen synthetic and stabilization enzymes

Chronic Benzene Exposure Aggravates Pressure Overload-Induced Cardiac Dysfunction

Benzene is a ubiquitous environmental pollutant abundant in household products, petrochemicals, and cigarette smoke. Benzene is a well-known carcinogen in humans and experimental animals; however, little is known about the cardiovascular toxicity of benzene. Recent population-based studies indicate that benzene exposure is associated with an increased risk for heart failure. Nonetheless, it is unclear whether benzene exposure is sufficient to induce and/or exacerbate heart failure. We examined the effects of benzene (50 ppm, 6 h/day, 5 days/week, and 6 weeks) or high-efficiency particulate absorbing-filtered air exposure on transverse aortic constriction (TAC)-induced pressure overload in male C57BL/6J mice. Our data show that benzene exposure had no effect on cardiac function in the Sham group; however, it significantly compromised cardiac function as depicted by a significant decrease in fractional shortening and ejection fraction, as compared with TAC/Air-exposed mice. RNA-seq analysis of the cardiac tissue from the TAC/benzene-exposed mice showed a significant increase in several genes associated with adhesion molecules, cell-cell adhesion, inflammation, and stress response. In particular, neutrophils were implicated in our unbiased analyses. Indeed, immunofluorescence studies showed that TAC/benzene exposure promotes infiltration of CD11b(+)/S100A8(+)/myeloperoxidase(+)-positive neutrophils in the hearts by 3-fold. In vitro, the benzene metabolites, hydroquinone, and catechol, induced the expression of P-selectin in cardiac microvascular endothelial cells by 5-fold and increased the adhesion of neutrophils to these endothelial cells by 1.5- to 2.0-fold. Benzene metabolite-induced adhesion of neutrophils to the endothelial cells was attenuated by anti-P-selectin antibody. Together, these data suggest that benzene exacerbates heart failure by promoting endothelial activation and neutrophil recruitment

Do Dimensions of Ethnic Identity Mediate the Association Between Perceived Ethnic Group Discrimination and Depressive Symptoms?

Ethnic group discrimination represents a notable risk factor that may contribute to mental health problems among ethnic minority college students. However, cultural resources (e.g., ethnic identity) may promote psychological adjustment in the context of group-based discriminatory experiences. In the current study, we examined the associations between perceptions of ethnic group discrimination and depressive symptoms, and explored dimensions of ethnic identity (i.e., exploration, resolution, and affirmation) as mediators of this process among 2,315 ethnic minority college students (age 18 to 30 years; 37% Black, 63% Latino). Results indicated that perceived ethnic group discrimination was associated positively with depressive symptoms among students from both ethnic groups. The relationship between perceived ethnic group discrimination and depressive symptoms was mediated by ethnic identity affirmation for Latino students, but not for Black students. Ethnic identity resolution was negatively and indirectly associated with depressive symptoms through ethnic identity affirmation for both Black and Latino students. Implications for promoting ethnic minority college students’ mental health and directions for future research are discussed

Physiological Biomimetic Culture System for Pig and Human Heart Slices

RATIONALE: Preclinical testing of cardiotoxicity and efficacy of novel heart failure therapies faces a major limitation: the lack of an in situ culture system that emulates the complexity of human heart tissue and maintains viability and functionality for a prolonged time. OBJECTIVE: To develop a reliable, easily reproducible, medium-throughput method to culture pig and human heart slices under physiological conditions for a prolonged period of time. METHODS AND RESULTS: Here, we describe a novel, medium-throughput biomimetic culture system that maintains viability and functionality of human and pig heart slices (300 µm thickness) for 6 days in culture. We optimized the medium and culture conditions with continuous electrical stimulation at 1.2 Hz and oxygenation of the medium. Functional viability of these slices over 6 days was confirmed by assessing their calcium homeostasis, twitch force generation, and response to β-adrenergic stimulation. Temporal transcriptome analysis using RNAseq at day 2, 6, and 10 in culture confirmed overall maintenance of normal gene expression for up to 6 days, while over 500 transcripts were differentially regulated after 10 days. Electron microscopy demonstrated intact mitochondria and Z-disc ultra-structures after 6 days in culture under our optimized conditions. This biomimetic culture system was successful in keeping human heart slices completely viable and functionally and structurally intact for 6 days in culture. We also used this system to demonstrate the effects of a novel gene therapy approach in human heart slices. Furthermore, this culture system enabled the assessment of contraction and relaxation kinetics on isolated single myofibrils from heart slices after culture. CONCLUSIONS: We have developed and optimized a reliable medium-throughput culture system for pig and human heart slices as a platform for testing the efficacy of novel heart failure therapeutics and reliable testing of cardiotoxicity in a 3D heart model

Exercise-Induced Changes in Glucose Metabolism Promote Physiological Cardiac Growth

Background: Exercise promotes metabolic remodeling in the heart, which is associated with physiological cardiac growth; however, it is not known whether or how physical activity–induced changes in cardiac metabolism cause myocardial remodeling. In this study, we tested whether exercise-mediated changes in cardiomyocyte glucose metabolism are important for physiological cardiac growth. Methods: We used radiometric, immunologic, metabolomic, and biochemical assays to measure changes in myocardial glucose metabolism in mice subjected to acute and chronic treadmill exercise. To assess the relevance of changes in glycolytic activity, we determined how cardiac-specific expression of mutant forms of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase affect cardiac structure, function, metabolism, and gene programs relevant to cardiac remodeling. Metabolomic and transcriptomic screenings were used to identify metabolic pathways and gene sets regulated by glycolytic activity in the heart. Results: Exercise acutely decreased glucose utilization via glycolysis by modulating circulating substrates and reducing phosphofructokinase activity; however, in the recovered state following exercise adaptation, there was an increase in myocardial phosphofructokinase activity and glycolysis. In mice, cardiac-specific expression of a kinase-deficient 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase transgene (GlycoLo mice) lowered glycolytic rate and regulated the expression of genes known to promote cardiac growth. Hearts of GlycoLo mice had larger myocytes, enhanced cardiac function, and higher capillary-to-myocyte ratios. Expression of phosphatase-deficient 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase in the heart (GlycoHi mice) increased glucose utilization and promoted a more pathological form of hypertrophy devoid of transcriptional activation of the physiological cardiac growth program. Modulation of phosphofructokinase activity was sufficient to regulate the glucose–fatty acid cycle in the heart; however, metabolic inflexibility caused by invariantly low or high phosphofructokinase activity caused modest mitochondrial damage. Transcriptomic analyses showed that glycolysis regulates the expression of key genes involved in cardiac metabolism and remodeling. Conclusions: Exercise-induced decreases in glycolytic activity stimulate physiological cardiac remodeling, and metabolic flexibility is important for maintaining mitochondrial health in the heart