LECTURES ON DIFFERENTIAL GEOMETRY OF AFFINE HYPERSURFACES TAEGU,1995

RYAN, PATRICK J. TOPOLOGY AND GEOMETRY RESEARCH CENTER 1995 Proceedings of the Topology and Geometry Research Vol.6 No.-

Progress and challenges of the bioartificial pancreas

Hwang Patrick T. J.,Shah Dishant K.,Garcia Jacob A.,Bae Chae Yun,Lim Dong-Jin,Huiszoon Ryan C.,Alexander Grant C.,Jun Ho-Wook 나노기술연구협의회 2016 Nano Convergence Vol.3 No.28

Pancreatic islet transplantation has been validated as a treatment for type 1 diabetes since it maintains consistent and sustained type 1 diabetes reversal. However, one of the major challenges in pancreatic islet transplantation is the body’s natural immune response to the implanted islets. Immunosuppressive drug treatment is the most popular immunomodulatory approach for islet graft survival. However, administration of immunosuppressive drugs gives rise to negative side effects, and long-term effects are not clearly understood. A bioartificial pancreas is a therapeutic approach to enable pancreatic islet transplantation without or with minimal immune suppression. The bioartificial pancreas encapsulates the pancreatic islets in a semi-permeable environment which protects islets from the body’s immune responses, while allowing the permeation of insulin, oxygen, nutrients, and waste. Many groups have developed various types of the bioartificial pancreas and tested their efficacy in animal models. However, the clinical application of the bioartificial pancreas still requires further investigation. In this review, we discuss several types of bioartificial pancreases and address their advantages and limitations. We also discuss recent advances in bioartificial pancreas applications with microfluidic or micropatterning technology.

Characterizing treatment pathways at scale using the OHDSI network

Hripcsak, George,Ryan, Patrick B.,Duke, Jon D.,Shah, Nigam H.,Park, Rae Woong,Huser, Vojtech,Suchard, Marc A.,Schuemie, Martijn J.,DeFalco, Frank J.,Perotte, Adler,Banda, Juan M.,Reich, Christian G.,S National Academy of Sciences 2016 PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF Vol.113 No.27

<P>Observational research promises to complement experimental research by providing large, diverse populations that would be infeasible for an experiment. Observational research can test its own clinical hypotheses, and observational studies also can contribute to the design of experiments and inform the generalizability of experimental research. Understanding the diversity of populations and the variance in care is one component. In this study, the Observational Health Data Sciences and Informatics (OHDSI) collaboration created an international data network with 11 data sources from four countries, including electronic health records and administrative claims data on 250 million patients. All data were mapped to common data standards, patient privacy was maintained by using a distributed model, and results were aggregated centrally. Treatment pathways were elucidated for type 2 diabetes mellitus, hypertension, and depression. The pathways revealed that the world is moving toward more consistent therapy over time across diseases and across locations, but significant heterogeneity remains among sources, pointing to challenges in generalizing clinical trial results. Diabetes favored a single first-line medication, metformin, to a much greater extent than hypertension or depression. About 10% of diabetes and depression patients and almost 25% of hypertension patients followed a treatment pathway that was unique within the cohort. Aside from factors such as sample size and underlying population (academic medical center versus general population), electronic health records data and administrative claims data revealed similar results. Large-scale international observational research is feasible.</P>

Performance of laterally loaded piles considering soil and interface parameters

Fatahi, Behzad,Basack, Sudip,Ryan, Patrick,Zhou, Wan-Huan,Khabbaz, Hadi Techno-Press 2014 Geomechanics & engineering Vol.7 No.5

To investigate the soil-pile interactive performance under lateral loads, a set of laboratory model tests was conducted on remoulded test bed of soft clay and medium dense sand. Then, a simplified boundary element analysis had been carried out assuming floating pile. In case of soft clay, it has been observed that lateral loads on piles can initiate the formation of a gap, soil heave and the tension crack in the vicinity of the soil surface and the interface, whereas in medium dense sand, a semi-elliptical depression zone can develop. Comparison of test and boundary element results indicates the accuracy of the solution developed. However, in the boundary element analysis, the possible shear stresses likely to be developed at the interface are ignored in order to simplify the existing complex equations. Moreover, it is unable to capture the influence of base restraint in case of a socketed pile. To bridge up this gap and to study the influence of the initial stress state and interface parameters, a field based case-study of laterally-loaded pile in layered soil with socketed tip is explored and modelled using the finite element method. The results of the model have been verified against known field measurements from a case-study. Parametric studies have been conducted to investigate the influence of the coefficient of lateral earth pressure and the interface strength reduction factor on the results of the model.

Organizational Citizenship Behaviors as Influenced by Supervisor Communication: The Role of Solidarity and Immediate Behaviors

Stephanie Kelly,Laura Graham,Patrick MacDonald,Ryan Goke 한국경영커뮤니케이션학회 2018 Business Communication Research and Practice Vol.1 No.2

Objectives:The purpose of this study was to assess the influence of supervisors’ immediate behaviors and solidarity on subordinates’ loyalty, obedience, and participation (i.e., organizational citizenship behaviors). A model was predicted in which supervisors’ immediate behaviors and solidarity indirectly induced subordinates’ organizational citizenship behaviors through the mediation of perceived immediacy. Methods: Electronic questionnaires were disseminated through social media. A total of 228 participants completed the questionnaire, representing a variety of occupations and supervisor communicative styles. Results: Each unidimensional measurement model was first subjected to a confirmatory factor analysis. The relationships between all variables were tested through Pearson correlations and were found to be both statistically significant and positive. Then, the data were analyzed through structural equation modeling. The data supported a path model in which perceived immediacy mediated supervisors’ solidarity and immediate behaviors as influence of subordinates’ loyalty. The mediation paths, however, were not supported for participation and obedience. Conclusions:It is speculated that mediation was not observed in the obedience and participation paths because not engaging in these two organizational citizenship behaviors can have indirect consequences for subordinates, whereas loyalty is truly altruistic. It was concluded that supervisor solidarity and immediate behaviors can be practiced and refined to enhance the workplace climate, increasing loyalty in subordinates.

Ventral inlay buccal mucosal graft urethroplasty: A novel surgical technique for the management of urethral stricture disease

Robert Caleb Kovell,Ryan Patrick Terlecki 대한비뇨의학회 2015 Investigative and Clinical Urology Vol.56 No.2

To describe the novel technique of ventral inlay substitution urethroplasty for the management of male anterior urethral stricturedisease. A 58-year-old gentleman with multifocal bulbar stricture disease measuring 7 cm in length was treated using a ventral inlaysubstitution urethroplasty. A dorsal urethrotomy was created, and the ventral urethral plated was incised. The edges of the urethralplate were mobilized without violation of the ventral corpus spongiosum. A buccal mucosa graft was harvested and affixedas a ventral inlay to augment the caliber of the urethra. The dorsal urethrotomy was closed over a foley catheter. No intraoperativeor postoperative complications occurred. Postoperative imaging demonstrated a widely patent urethra. After three years of followup,the patient continues to do well with no voiding complaints and low postvoid residuals. Ventral inlay substitution urethroplastyappears to be a safe and feasible technique for the management of bulbar urethral strictures.

A CONTINUOUSLY OPERABLE HYDRAULIC MODEL OF SELECTIVE WITHDRAWAL FROM A STRATIFIED RESERVOIR

ETTEMA ROBERT,MUSTE MARIAN,ODGAARD JACOB,RYAN PATRICK,LOCHER FREDERICK,TU SCOTT 한국수자원학회 2005 한국수자원학회 학술대회 Vol.2005 No.1

Multivalent Electrochemistry of Spinel Mg_<i>x</i>Mn_3-<i>x</i>O₄ Nanocrystals

Kim, Chunjoong,Adil, Abdullah A.,Bayliss, Ryan D.,Kinnibrugh, Tiffany L.,Lapidus, Saul H.,Nolis, Gene M.,Freeland, John W.,Phillips, Patrick J.,Yi, Tanghong,Yoo, Hyun Deog,Kwon, Bob Jin,Yu, Young-Sang American Chemical Society 2018 Chemistry of materials Vol.30 No.5

<P>Oxides undergoing reversible electrochemical cycling of Mg<SUP>2+</SUP> ions would enable novel battery concepts beyond Li<SUP>+</SUP>, capable of storing large amounts of energy. However, materials showing this chemical reactivity are scarce. Suitable candidates require small particles to shorten transport lengths, together with chemically complex structures that promote cation mobility, such as spinel. These goals pose a challenge for materials chemists. Here, nanocrystals of spinel-type Mg<SUB>0.5</SUB>Mn<SUB>2.5</SUB>O<SUB>4</SUB> were prepared using colloidal synthesis, and their electrochemical activity is presented. Cycling in an aqueous Mg<SUP>2+</SUP> electrolyte led to a reversible transformation between a reduced spinel and an oxidized layered framework. This reaction involves large amounts of capacity because of the full oxidation to Mn<SUP>4+</SUP>, through the extraction of both Mg<SUP>2+</SUP> and, in the first cycle, Mn<SUP>2+</SUP> ions. Re-formation of the spinel upon reduction resulted in enrichment with Mg<SUP>2+</SUP>, indicating that its insertion is more favorable than that of Mn<SUP>2+</SUP>. Incorporation of water into the structure was not indispensable for the transformation, as revealed by experiments in non-aqueous electrolytes and infrared spectroscopy. The findings open the door for the use of similar nanocrystals in Mg batteries provided that electrolytes with suitable anodic stability are discovered, thereby identifying novel routes toward electrode materials for batteries with high energy.</P> [FIG OMISSION]</BR>

Proof of concept: Exposing the myth of urethral atrophy after artificial urinary sphincter via assessment of circumferential recovery after capsulotomy and intraoperative pressure profiling of the pressure regulating balloon

Amy Marcia Pearlman,Alison Marie Rasper,Ryan Patrick Terlecki 대한비뇨의학회 2018 Investigative and Clinical Urology Vol.59 No.4

Purpose: Rate of continence after artificial urinary sphincter (AUS) placement appears to decline with time. After appropriate workup to exclude inadvertent device deactivation, development of urge or overflow incontinence, and fluid loss, many assume recurrent stress urinary incontinence (rSUI) to be secondary to nonmechanical failure, asserting urethral atrophy as the etiology. We aimed to characterize the extent of circumferential urethral recovery following capsulotomy and that of pressure regulating balloon (PRB) material fatigue in men undergoing AUS revision for rSUI. Materials and Methods: Retrospective review of a single surgeon database was performed. Cases of AUS removal/replacement for rSUI involving ventral subcuff capsulotomy and intraoperative PRB pressure profile assessments were identified. Results: The described operative approach involving capsulotomy was applied in 7 patients from November 2015 to September 2017. Mean patient age was 75 years. Mean time between AUS placement and revision was 103 months. Urethral circumference increased in all patients after capsulotomy (mean increase 1.1 cm; range 0.5–2.5 cm). Cuff size increased, remained the same, and decreased in 2, 3, and 2 patients, respectively. Six of 7 patients underwent PRB interrogation. Four of these 6 PRBs (66.7%) demonstrated pressures in a category below the reported range of the original manufacturer rating. Conclusions: Despite visual appearance to suggest urethral atrophy, subcuff capsulotomy results in increased urethral circumference in all patients. Furthermore, intraoperative PRB profiling demonstrates material fatigue. Future multicenter efforts are warranted to determine if capsulotomy, with or without PRB replacement, may simplify surgical management of rSUI with reductions in cost and/or morbidity.

Comparison of First-Line Dual Combination Treatments in Hypertension: Real-World Evidence from Multinational Heterogeneous Cohorts

Seng Chan You,Sungjae Jung,Joel N. Swerdel,Patrick B. Ryan,Martijn J. Schuemie,Marc A. Suchard,Seongwon Lee,Jaehyeong Cho,George Hripcsak,Rae Woong Park,Sungha Park 대한심장학회 2020 Korean Circulation Journal Vol.50 No.1

Background and Objectives: 2018 ESC/ESH Hypertension guideline recommends 2-drug combination as initial anti-hypertensive therapy. However, real-world evidence for effectiveness of recommended regimens remains limited. We aimed to compare the effectiveness of first-line anti-hypertensive treatment combining 2 out of the following classes: angiotensin-converting enzyme (ACE) inhibitors/angiotensin-receptor blocker (A), calcium channel blocker (C), and thiazide-type diuretics (D). Methods: Treatment-naïve hypertensive adults without cardiovascular disease (CVD) who initiated dual anti-hypertensive medications were identified in 5 databases from US and Korea. The patients were matched for each comparison set by large-scale propensity score matching. Primary endpoint was all-cause mortality. Myocardial infarction, heart failure, stroke, and major adverse cardiac and cerebrovascular events as a composite outcome comprised the secondary measure. Results: A total of 987,983 patients met the eligibility criteria. After matching, 222,686, 32,344, and 38,513 patients were allocated to A+C vs. A+D, C+D vs. A+C, and C+D vs. A+D comparison, respectively. There was no significant difference in the mortality during total of 1,806,077 person-years: A+C vs. A+D (hazard ratio [HR], 1.08; 95% confidence interval [CI], 0.97−1.20; p=0.127), C+D vs. A+C (HR, 0.93; 95% CI, 0.87−1.01; p=0.067), and C+D vs. A+D (HR, 1.18; 95% CI, 0.95−1.47; p=0.104). A+C was associated with a slightly higher risk of heart failure (HR, 1.09; 95% CI, 1.01−1.18; p=0.040) and stroke (HR, 1.08; 95% CI, 1.01−1.17; p=0.040) than A+D. Conclusions: There was no significant difference in mortality among A+C, A+D, and C+D combination treatment in patients without previous CVD. This finding was consistent across multi-national heterogeneous cohorts in real-world practice.