Publications by authors named "Sean Kang"

Objective:  The aim of this study was to assess the impact of a tactical harness on three-dimensional motion of the thoracic limb in dogs.

Animals:  Five adult mixed-breed dogs (age: 4-6 years, weight: 25-35 kg) were used in this study.

Methods:  Custom-fit tactical harnesses were applied to each dog and 19 retroreflective skin markers were used to determine three-dimensional joint motion during dynamic motion, with and without the harness.

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Objectives: Regaining and maintaining sternal stability are key to recovery after cardiac surgery and resuming baseline quality of life. Montage (ABYRX) is a moldable, calcium phosphate-based putty that adheres to bleeding bone, hardens after application, and is resorbed and replaced with bone during the remodeling process. We evaluate the feasibility, safety, and efficacy of enhanced sternal closure with this novel putty to accelerate recovery in patients after sternotomy.

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Extracellular matrix bioscaffolds can influence the cardiac microenvironment and modulate endogenous cellular mechanisms. These materials can optimize cardiac surgery for repair and reconstruction. We investigated the biocompatibility and bioinductivity of bovine pericardium fixed via dye-mediated photo-oxidation on human cardiac fibroblast activity.

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Cardiovascular disease is the most prevalent cause of morbidity and mortality in diabetes. Epicardial adipose tissue (EAT) lies in direct contact with the myocardium and coronary arteries and can influence cardiac (patho) physiology through paracrine signaling pathways. This study hypothesized that the proteins released from EAT represent a critical molecular link between the diabetic state and coronary artery endothelial cell dysfunction.

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During learning, interleaving exemplars from different categories (e.g., ABCBCACAB) rather than blocking by category (e.

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Coronary heart disease is a leading cause of death. Tissue remodeling and fibrosis results in cardiac pump dysfunction and ischemic heart failure. Cardiac fibroblasts may rebuild damaged tissues when prompted by suitable environmental cues.

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Background: Empagliflozin, an SGLT2 inhibitor, has shown remarkable reductions in cardiovascular mortality and heart failure admissions (EMPA-REG OUTCOME). However, the mechanism underlying the heart failure protective effects of empagliflozin remains largely unknown. Cardiac fibroblasts play an integral role in the progression of structural cardiac remodelling and heart failure, in part, by regulating extracellular matrix (ECM) homeostasis.

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Although previous research on retrieval practice (RP) has predominantly featured stimuli with discrete right-or-wrong answers, continuous measures offer potentially greater sensitivity in assessing the effects of RP on memory precision. The present study used a colour gradient (125 points ranging from magenta to yellow) as a continuous response variable. The colours of different images were learned through either RP or restudy and either one or three cycles of practice after initial study.

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Objectives: Fluoroquinolone (FQ) antibiotics are associated with adverse aortic clinical events. We assessed human aortic myofibroblast-mediated extracellular matrix (ECM) dysregulation as a possible cellular mechanism underlying FQ-associated aortopathy.

Methods: Human aortic myofibroblasts were isolated from patients with aortopathy undergoing elective ascending aortic resection (N = 9).

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Structural cardiac remodeling after ischemic injury can induce a transition to heart failure from progressive loss of cardiac function. Cellular regenerative therapies are promising but face significant translational hurdles. Tissue extracellular matrix (ECM) holds the necessary environmental cues to stimulate cell-based endogenous myocardial repair pathways and promote adaptive remodeling toward functional recovery.

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The thermostable Geobacillus stearothermophilus GsI-IIC intron is among the few bacterial group II introns found to proliferate to high copy number in its host genome. Here, we developed a bacterial genetic assay for retrohoming and biochemical assays for protein-dependent and self-splicing of GsI-IIC. We found that GsI-IIC, like other group IIC introns, retrohomes into sites having a 5'-exon DNA hairpin, typically from a bacterial transcription terminator, followed by short intron-binding sequences (IBSs) recognized by base pairing of exon-binding sequences (EBSs) in the intron RNA.

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Hyperglycaemia is a major contributor to diabetic cardiovascular disease with hyperglycaemia-induced endothelial dysfunction recognized as the initiating cause. Coagulation pathway-regulated proteinase-activated receptors (PARs) that can regulate vascular tone in vivo cause eNOS-mediated endothelium-dependent vasodilation; but, the impact of hyperglycaemia on this vasodilatory action of PAR stimulation and the signalling pathways involved are unknown. We hypothesized that vascular sodium-glucose co-transporter 2 activity and hyperglycaemia-induced oxidative stress involving Src-kinase, EGF receptor-kinase, Rho-kinase and protein-kinase-C biochemical signalling pathways would compromise PAR2-mediated endothelium-dependent vasodilation.

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Objective: Intrapericardial fibrous adhesions increase the risk of sternal reentry. Proteoglycan 4/lubricin (PRG4) is a mucin-like glycoprotein that lubricates tissue compartments and prevents inflammation. We characterized PRG4 expression in human pericardium and examined its effects in vitro on human cardiac myofibroblast fibrotic activity and in vivo as a measure of its therapeutic potential to prevent adhesions.

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Extracellular matrix (ECM) maintains a reservoir of bioactive growth factors and matricellular proteins that provide bioinductive effects on local cells that influence phenotype and behaviors. Bioactive acellular ECM scaffolds can be used therapeutically to stimulate adaptive tissue repair. Fibroblast growth factor-2 (FGF-2) attenuates transforming growth factor-β1 (TGF-β1)-mediated cardiac fibrosis.

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Background: Suspected genetic causes for extracellular matrix (ECM) dysregulation in the ascending aorta in patients with bicuspid aortic valves (BAV) have influenced strategies and thresholds for surgical resection of BAV aortopathy. Using 4-dimensional (4D) flow cardiac magnetic resonance imaging (CMR), we have documented increased regional wall shear stress (WSS) in the ascending aorta of BAV patients.

Objectives: This study assessed the relationship between WSS and regional aortic tissue remodeling in BAV patients to determine the influence of regional WSS on the expression of ECM dysregulation.

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If multiple opportunities are available to review to-be-learned material, should a review occur soon after initial study and recur at progressively expanding intervals, or should the reviews occur at equal intervals? Landauer and Bjork (1978) argued for the superiority of expanding intervals, whereas more recent research has often failed to find any advantage. However, these prior studies have generally compared expanding versus equal-interval training within a single session, and have assessed effects only upon a single final test. We argue that a more generally important goal would be to maintain high average performance over a considerable period of training.

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Reviewing information stored in memory will generally strengthen that information, so it seems reasonable that reviews should make it harder to replace the information in memory if it is later found to be erroneous. In Experiment 1, subjects learned three facts about each of 12 topics. On Day 2, the same facts were either reread, tested, or not reviewed; then the facts were "corrected" with new replacement facts.

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Second language (L2) instruction programs often ask learners to repeat aloud words spoken by a native speaker. However, recent research on retrieval practice has suggested that imitating native pronunciation might be less effective than drill instruction, wherein the learner is required to produce the L2 words from memory (and given feedback). We contrasted the effectiveness of imitation and retrieval practice drills on learning L2 spoken vocabulary.

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We have reported that melatonin induces histone hyperacetylation in mouse neural stem cells, suggesting an epigenetic role for this pleiotropic hormone. To support such a role, it is necessary to demonstrate that melatonin produces similar effects in vivo. Histone acetylation, following chronic treatment with melatonin (4μg/ml in drinking water for 17 days), was examined by western blotting in selected rat brain regions.

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Sereno, O'Donnell, and Sereno (2009) reported that words are recognized faster in a lexical decision task when their referents are physically large than when they are small, suggesting that "semantic size" might be an important variable that should be considered in visual word recognition research and modelling. We sought to replicate their size effect, but failed to find a significant latency advantage in lexical decision for "big" words (cf. "small" words), even though we used the same word stimuli as Sereno et al.

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Is learning of a complex functional relationship enhanced by trying to predict what output will go with a given input, as compared to studying an input-output pair? We examined learning of a bilinear function and transfer to new items outside the trained range. Subjects either saw the input-output pairs (study-only condition) or attempted to guess the output and then saw the pair (test/study condition). The total study times were equated, and motivation was enhanced with a monetary bonus.

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Studies examining the beneficial effect of testing on memory have relied almost exclusively on verbal materials. Whether testing can improve the learning of novel, abstract visuospatial information was investigated, using Chinese characters as study stimuli. Subjects with no prior Chinese language experience studied English words paired with their Chinese equivalents.

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Nairne, Thompson, and Pandeirada (2007) reported a series of experiments in which processing unrelated words in terms of their relevance to a grasslands survival scenario led to better retention relative to other semantic processing tasks. The impetus for their study was the premise that human memory systems evolved under the selection pressures of our ancestral past. In 3 experiments, we extended this functional approach to investigate the congruity effect-the common finding that people remember items better if those items are congruent with the way in which they are processed.

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