Molecular Dynamics Simulations of Plastic Material Deformation in Machining with a Round Cutting Edge

김창주,Rhett Mayor,Jun Ni 한국정밀공학회 2012 International Journal of Precision Engineering and Vol. No.

This paper reviews the application of the molecular dynamics simulation approach to the high-resolution visualization of the plastic material flow at the tool/workpiece interface during orthogonal cutting. MD simulation techniques have been applied to nano-scale processes, but due to restrictions in the model size and computational time, they have not been utilized to investigate processes occurring at the micro-scale. Techniques employed to extend the MD simulation techniques to the micro-scale are discussed. Preferred ranges for model parameters that provide for sufficient resolution in order to adequately describe the characteristic features of the plastic material flow, yet achieve significant reduction in the model computational times, are identified. An investigation of the plastic material flow at the tool/workpiece interface as the uncut chip thickness increases from 10% to 90% of the edge radius of the tool was undertaken. A key observation is that there is a marked variation in the geometry of the observed characteristic features, most notable being the rotation and growth of the stable built-up edge as the uncut chip thickness increases. Furthermore, the transition between the plowing and cutting regimes is observed.

A critique: The good and bad of a review

Debbie McMullen,Rhett McClean,Sok Cheon Pak 셀메드 세포교정의약학회 2015 TANG Vol.5 No.3

Evidence based medicine involves using both the individual clinician’s expertise and the current best available external clinical evidence from systematic research in deciding on the appropriate care for individual patients. The current approach to evidence based practice in healthcare adds a third component which is patient values. Evidence based practice is thus a triad, in which the practitioner’s expertise, research evidence and the patient’s values are all given consideration. The balance to be struck between them depends on the individual case. The literature indicates that complementary medicine practitioners are moving away from traditional knowledge and towards the use of evidence based practice in their clinical discussions. In the context of the daily practice of complementary medicine practitioners and their continuing development of their knowledge base of evidence based practice, this short review discusses the good and bad of a review journal article.

Meshed Acellular Dermal Matrix for Two-Staged Prepectoral Breast Reconstruction: An Institutional Experience

Luo Jessica,Willis Rhett N.,Ohlsen Suzanna M.,Piccinin Meghan,Moores Neal,Kwok Alvin C.,Agarwal Jayant P. 대한성형외과학회 2022 Archives of Plastic Surgery Vol.49 No.1

The introduction of acellular dermal matrix (ADM) to breast reconstruction has allowed surgeons to reexplore the prepectoral implant placement technique in postmastectomy breast reconstruction. Our institution adopted a novel approach using meshed ADM to lessen the financial burden of increased ADM utilization with the prepectoral breast reconstruction. This is a retrospective, single-center review of two-stage prepectoral breast reconstruction using meshed human-derived ADM for anterior prosthesis coverage. Patient demographics, oncologic data, perioperative characteristics, and complications were examined and reported as means with standard deviations. Cost-saving with the meshed technique was evaluated. Forty-eight patients (72 breasts) with a mean age of 48.5 ± 15.0 years (range 26–70 years) were included in the study. The mean follow-up time was 13.2 ± 4.4 months (range 4.1–25.8 months). Nineteen breasts (24.6%) experienced complications, with seromas being the most common complication (12.5%, n = 9). Expander removal and reoperation occurred at a rate of 8.3 and 9.7%, respectively. The average time to drain removal was 18.8 ± 6.6 days (range 8–32 days). Meshed ADM provided an average cost savings of $6,601 for unilateral and $13,202 for bilateral reconstructions. Our study found that human-derived meshed ADM can be safely used in two-staged prepectoral tissue expander-based breast reconstruction and can result in significant cost savings.

Molecular Dynamics Simulations of Plastic Material Deformation in Machining with a Round Cutting Edge

Kim, Chang-Ju,Mayor, Rhett,Ni, Jun 한국정밀공학회 2012 International Journal of Precision Engineering and Vol.13 No.8

This paper reviews the application of the molecular dynamics simulation approach to the high-resolution visualization of the plastic material flow at the tool/workpiece interface during orthogonal cutting. MD simulation techniques have been applied to nano-scale processes, but due to restrictions in the model size and computational time, they have not been utilized to investigate processes occurring at the micro-scale. Techniques employed to extend the MD simulation techniques to the micro-scale are discussed. Preferred ranges for model parameters that provide for sufficient resolution in order to adequately describe the characteristic features of the plastic material flow, yet achieve significant reduction in the model computational times, are identified. An investigation of the plastic material flow at the tool/workpiece interface as the uncut chip thickness increases from 10% to 90% of the edge radius of the tool was undertaken. A key observation is that there is a marked variation in the geometry of the observed characteristic features, most notable being the rotation and growth of the stable built-up edge as the uncut chip thickness increases. Furthermore, the transition between the plowing and cutting regimes is observed.

Meshed Acellular Dermal Matrix for Two-Staged Prepectoral Breast Reconstruction: An Institutional Experience

Luo Jessica,Willis Rhett N.,Ohlsen Suzanna M.,Piccinin Meghan,Moores Neal,Kwok Alvin C.,Agarwal Jayant P. 대한성형외과학회 2022 Archives of Plastic Surgery Vol.49 No.2

The introduction of acellular dermal matrix (ADM) to breast reconstruction has allowed surgeons to reexplore the prepectoral implant placement technique in postmastectomy breast reconstruction. Our institution adopted a novel approach using meshed ADM to lessen the financial burden of increased ADM utilization with the prepectoral breast reconstruction. This is a retrospective, single-center review of two-stage prepectoral breast reconstruction using meshed human-derived ADM for anterior prosthesis coverage. Patient demographics, oncologic data, perioperative characteristics, and complications were examined and reported as means with standard deviations. Cost-saving with the meshed technique was evaluated. Forty-eight patients (72 breasts) with a mean age of 48.5 ± 15.0 years (range 26–70 years) were included in the study. The mean follow-up time was 13.2 ± 4.4 months (range 4.1–25.8 months). Nineteen breasts (24.6%) experienced complications, with seromas being the most common complication (12.5%, n = 9). Expander removal and reoperation occurred at a rate of 8.3 and 9.7%, respectively. The average time to drain removal was 18.8 ± 6.6 days (range 8–32 days). Meshed ADM provided an average cost savings of $6,601 for unilateral and $13,202 for bilateral reconstructions. Our study found that human-derived meshed ADM can be safely used in two-staged prepectoral tissue expander-based breast reconstruction and can result in significant cost savings.

An Experimental Investigation on Semi-Solid Forming of Micro/Meso-Scale Features

Kim, Gap-Yong,Ni, Jun,Mayor, Rhett,Kim, Heesool ASME International 2007 JOURNAL OF MANUFACTURING SCIENCE AND ENGINEERING-T Vol.129 No.2

Evidence based practice within the complementary medicine context

Lisa McLean,Peter Steve Micalos,Rhett McClean,Sok Cheon Pak 셀메드 세포교정의약학회 2016 셀메드 (CellMed) Vol.6 No.3

Evidence based practice (EBP) is a system of applying the most current and valid high quality evidence to support clinical decision making in a healthcare setting. In the twenty five years since its inception, EBP has become the accepted benchmark for excellence in healthcare. Although the system emerged within the biomedical sciences, in the years since EBP has become normative across all healthcare modalities from dentistry, allied health to complementary and alternative medicine (CAM). Practicing evidence based medicine within any modality potentially offers the patient the best available care based on high quality evidence. Yet it is the nature of the evidence that provokes some questions about the suitability of EBP across all modalities of healthcare. The meta analysis of randomized controlled trial (RCT) stands at the pinnacle of the hierarchy of evidence in EBP. This forms a challenge to CAM due to the difficulty in reducing the elementals of a holistic naturopathic assessment of a patient into an answerable question to be tested within a RCT. On one level this makes EBP paradigmatically incompatible with CAM, yet on another level it presents the opportunity to redefine the parameters of what is considered high level evidence. EBP has become a tool, and at times a weapon wielded by governments and health insurance companies to direct healthcare funding and policy. The implications of the nature of accepted evidence are becoming far reaching. The pursuit of the best available healthcare for each individual is the focus of EBP. However, the injudicious use of this system to direct health policy is fraught with biomedical bias and dominance. This issue raises the challenge to CAM to present high level evidence according to the rules of evidence, or face the annihilation of centuries of empirical knowledge.

Intrawound Vancomycin Powder in Primary Total Hip Arthroplasty Increases Rate of Sterile Wound Complications

( Brian L. Dial ),( Alexander J. Lampley ),( Cynthia L. Green ),( Rhett Hallows ) 대한고관절학회 2018 Hip and Pelvis Vol.30 No.1

Purpose: Total hip arthroplasty (THA) is a successful surgery for the treatment of hip osteoarthritis; however, the risk of a post-operative prosthetic joint infection (PJI) remains at 1% to 2%. The purpose of this study was to investigate the safety profile of using vancomycin powder (VP) to reduce infection rates by reviewing acute postoperative complications. Materials and Methods: A retrospective review of 265 consecutive patients undergoing THA was performed. The first 128 patients, the control group, did not receive VP, and the subsequent 137 patients, the VP group, received VP at the time of wound closure. Patient demographic data, medical comorbidities, and perioperative information were compared. Results: The primary outcome was a post-operative surgical complication within 90 days from surgery. The control and VP group’s demographic, medical comorbidities and perioperative information data were statistically similar. Deep infection rate in the control group was 5.5%, whereas the deep infection rate in the VP group was 0.7% (P=0.031). Sterile wound complication rate was 4.4% in the VP group, and 0% in the control group (P=0.030). Remaining complications were not statistically different between the groups. Conclusion: VP was associated with an increase rate of sterile wound complications compared to the control group. The rate of PJI was decreased with the use of VP. We do not recommend for or against the use of VP at time of wound closure to prevent PJI, and higher powered studies will need to be performed to demonstrate the efficacy of VP.