A predictive model to guide management of the overlap region between target volume and organs at risk in prostate cancer volumetric modulated arc therapy

Mattes, Malcolm D.,Lee, Jennifer C.,Elnaiem, Sara,Guirguis, Adel,Ikoro, N.C.,Ashamalla, Hani The Korean Society for Radiation Oncology 2014 Radiation Oncology Journal Vol.32 No.1

Purpose: The goal of this study is to determine whether the magnitude of overlap between planning target volume (PTV) and rectum ($Rectum_{overlap}$) or PTV and bladder ($Bladder_{overlap}$) in prostate cancer volumetric-modulated arc therapy (VMAT) is predictive of the dose-volume relationships achieved after optimization, and to identify predictive equations and cutoff values using these overlap volumes beyond which the Quantitative Analyses of Normal Tissue Effects in the Clinic (QUANTEC) dose-volume constraints are unlikely to be met. Materials and Methods: Fifty-seven patients with prostate cancer underwent VMAT planning using identical optimization conditions and normalization. The PTV (for the 50.4 Gy primary plan and 30.6 Gy boost plan) included 5 to 10 mm margins around the prostate and seminal vesicles. Pearson correlations, linear regression analyses, and receiver operating characteristic (ROC) curves were used to correlate the percentage overlap with dose-volume parameters. Results: The percentage $Rectum_{overlap}$ and $Bladder_{overlap}$ correlated with sparing of that organ but minimally impacted other dose-volume parameters, predicted the primary plan rectum $V_{45}$ and bladder $V_{50}$ with $R^2$ = 0.78 and $R^2$ = 0.83, respectively, and predicted the boost plan rectum $V_{30}$ and bladder $V_{30}$ with $R^2$ = 0.53 and $R^2$ = 0.81, respectively. The optimal cutoff value of boost $Rectum_{overlap}$ to predict rectum $V_{75}$ >15% was 3.5% (sensitivity 100%, specificity 94%, p < 0.01), and the optimal cutoff value of boost $Bladder_{overlap}$ to predict bladder $V_{80}$ >10% was 5.0% (sensitivity 83%, specificity 100%, p < 0.01). Conclusion: The degree of overlap between PTV and bladder or rectum can be used to accurately guide physicians on the use of interventions to limit the extent of the overlap region prior to optimization.

Mechanical Circulatory Support in the Cardiac Catheterization Laboratory for Cardiogenic Shock

Matt Ryan,Divaka Perera,Natalia Briceno 대한심장학회 2019 Korean Circulation Journal Vol.49 No.3

Despite the development of acute revascularisation, the mortality rate for cardiogenic shock remains around 50%. Mechanical circulatory support devices have long held promise in improving outcomes in shock, but high-quality evidence of benefit has not been forthcoming. In this article we review the currently available devices for treating shock, their physiological effects and the evidence base for their use in practice. We subsequently look ahead within this developing field, including new devices and novel indications for established technology.

Gly184 of the Escherichia coli cAMP receptor protein provides optimal context for both DNA binding and RNA polymerase interaction

Matt N. Hicks,Sanjiva Gunasekara,Jose Serate,박진,Pegah Mosharaf,Yue Zhou,이진원,윤환 한국미생물학회 2017 The journal of microbiology Vol.55 No.10

The Escherichia coli cAMP receptor protein (CRP) utilizes the helix-turn-helix motif for DNA binding. The CRP’s recognition helix, termed F-helix, includes a stretch of six amino acids (Arg180, Glu181, Thr182, Val183, Gly184, and Arg185) for direct DNA contacts. Arg180, Glu181 and Arg185 are known as important residues for DNA binding and specificity, but little has been studied for the other residues. Here we show that Gly184 is another F-helix residue critical for the transcriptional activation function of CRP. First, glycine was repeatedly selected at CRP position 184 for its unique ability to provide wild type-level transcriptional activation activity. To dissect the glycine requirement, wild type CRP and mutants G184A, G184F, G184S, and G184Y were purified and their in vitro DNA-binding activity was measured. G184A and G184F displayed reduced DNA binding, which may explain their low transcriptional activation activity. However, G184S and G184Y displayed apparently normal DNA affinity. Therefore, an additional factor is needed to account for the diminished transcriptional activation function in G184S and G184Y, and the best explanation is perturbations in their interaction with RNA polymerase. The fact that glycine is the smallest amino acid could not fully warrant its suitability, as shown in this study. We hypothesize that Gly184 fulfills the dual functions of DNA binding and RNA polymerase interaction by conferring conformational flexibility to the F-helix.

H2-MHR PRE-CONCEPTUAL DESIGN SUMMARY FOR HYDROGEN PRODUCTION

MATT RICHARDS 한국원자력학회 2007 Nuclear Engineering and Technology Vol.39 No.1

Hydrogen and electricity are expected to dominate the world energy system in the long term. The world currently consumes about 50 million metric tons of hydrogen per year, with the bulk of it being consumed by the chemical and refining industries. The demand for hydrogen is expected to increase, especially if the U.S. and other countries shift their energy usage towards a hydrogen economy, with hydrogen consumed as an energy commodity by the transportation, residential and commercial sectors. However, there is strong motivation to not use fossil fuels in the future as a feedstock for hydrogen production, because the greenhouse gas carbon dioxide is a byproduct and fossil fuel prices are expected to increase significantly. An advanced reactor technology receiving considerable international interest for both electricity and hydrogen production, is the modular helium reactor (MHR), which is a passively safe concept that has evolved from earlier high-temperature gas-cooled reactor (HTGR) designs. For hydrogen production, this concept is referred to as the H2-MHR. Two different hydrogen production technologies are being investigated for the H2-MHR; an advanced sulfur-iodine (SI) thermochemical water splitting process and hightemperature electrolysis (HTE). This paper describes pre-conceptual design descriptions and economic evaluations of fullscale, nth-of-a-kind SI-Based and HTE-Based H2-MHR plants. Hydrogen production costs for both types of plants are estimated to be approximately $2 per kilogram.

Should Workers Avoid Consumption of Chilled Fluids in a Hot and Humid Climate?

Matt B. Brearley 한국산업안전보건공단 산업안전보건연구원 2017 Safety and health at work Vol.8 No.4

Despite provision of drinking water as the most common method of occupational heat stress prevention, there remains confusion in hydration messaging to workers. During work site interactions in a hot and humid climate, workers commonly report being informed to consume tepid fluids to accelerate rehydration. When questioned on the evidence supporting such advice, workers typically cite that fluid absorption is delayed by ingestion of chilled beverages. Presumably, delayed absorption would be a product of fluid delivery from the gut to the intestines, otherwise known as gastric emptying. Regulation of gastric emptying is multifactorial, with gastric volume and beverage energy density the primary factors. If gastric emptying is temperature dependent, the impact of cooling is modest in both magnitude and duration ( 5 minutes) due to the warming of fluids upon ingestion, particularly where workers have elevated core temperature. Given that chilled beverages are most preferred by workers, and result in greater consumption than warm fluids during and following physical activity, the resultant increased consumption of chilled fluids would promote gastric emptying through superior gastric volume. Hence, advising workers to avoid cool/cold fluids during rehydration appears to be a misinterpretation of the research. More appropriate messaging to workers would include the thermal benefits of cool/cold fluid consumption in hot and humid conditions, thereby promoting autonomy to trial chilled beverages and determine personal preference. In doing so, temperature-based palatability would be maximized and increase the likelihood of workers maintaining or restoring hydration status during and after their work shift.

Giant Magellan Telescope Overview

Matt Johns 한국천문학회 2008 天文學會報 Vol.33 No.1

Spacecraft Guidance Algorithms for Asteroid Intercept and Rendezvous Missions

Matt Hawkins,Yanning Guo,Bong Wie 한국항공우주학회 2012 International Journal of Aeronautical and Space Sc Vol.13 No.2

This paper presents a comprehensive review of spacecraft guidance algorithms for asteroid intercept and rendezvous missions. Classical proportional navigation (PN) guidance is reviewed first, followed by pulsed PN guidance, augmented PN guidance, predictive feedback guidance, Lambert guidance, and other guidance laws based on orbit perturbation theory. Optimal feedback guidance laws satisfying various terminal constraints are also discussed. Finally, the zero-effort-velocity (ZEV) error, analogous to the well-known zero-effort-miss (ZEM) distance, is introduced, leading to a generalized ZEM/ZEV guidance law. These various feedback guidance laws can be easily applied to real asteroid intercept and rendezvous missions. However, differing mission requirements and spacecraft capabilities will require continued research on terminal-phase guidance laws.

Dosimetric comparison of axilla and groin radiotherapy techniques for high-risk and locally advanced skin cancer

Mattes, Malcolm D.,Zhou, Ying,Berry, Sean L.,Barker, Christopher A. The Korean Society for Radiation Oncology 2016 Radiation Oncology Journal Vol.34 No.2

Purpose: Radiation therapy targeting axilla and groin lymph nodes improves regional disease control in locally advanced and high-risk skin cancers. However, trials generally used conventional two-dimensional radiotherapy (2D-RT), contributing towards relatively high rates of side effects from treatment. The goal of this study is to determine if three-dimensional conformal radiation therapy (3D-CRT), intensity-modulated radiation therapy (IMRT), or volumetric-modulated arc therapy (VMAT) may improve radiation delivery to the target while avoiding organs at risk in the clinical context of skin cancer regional nodal irradiation. Materials and Methods: Twenty patients with locally advanced/high-risk skin cancers underwent computed tomography simulation. The relevant axilla or groin planning target volumes and organs at risk were delineated using standard definitions. Paired t-tests were used to compare the mean values of several dose-volumetric parameters for each of the 4 techniques. Results: In the axilla, the largest improvement for 3D-CRT compared to 2D-RT was for homogeneity index (13.9 vs. 54.3), at the expense of higher lung $V_{20}$ (28.0% vs. 12.6%). In the groin, the largest improvements for 3D-CRT compared to 2D-RT were for anorectum $D_{max}$ (13.6 vs. 38.9 Gy), bowel $D_{200cc}$ (7.3 vs. 23.1 Gy), femur $D_{50}$ (34.6 vs. 57.2 Gy), and genitalia $D_{max}$ (37.6 vs. 51.1 Gy). IMRT had further improvements compared to 3D-CRT for humerus $D_{mean}$ (16.9 vs. 22.4 Gy), brachial plexus $D_5$ (57.4 vs. 61.3 Gy), bladder $D_5$ (26.8 vs. 36.5 Gy), and femur $D_{50}$ (18.7 vs. 34.6 Gy). Fewer differences were observed between IMRT and VMAT. Conclusion: Compared to 2D-RT and 3D-CRT, IMRT and VMAT had dosimetric advantages in the treatment of nodal regions of skin cancer patients.

[AMERICA’S DECABILLIONAIRE FAMILIES] 자산 100억 달러 보유한 美 45개 가문

Matt Durot,Andrea Murphy 중앙일보에스 2024 Forbes Korea = 포브스 코리아 Vol.2024 No.4

Quantitative Evaluation of Partial Delamination in Thermal Barrier Coatings Using Ultrasonic C-scan Imaging

matte kishore babu,Ho-Girl Lee,A. Gezaei Abera,H. J. Kim,C. S. Seok,S. J. Song 한국정밀공학회 2020 International Journal of Precision Engineering and Vol.21 No.1

Adoption of thermal barrier coatings (TBC) will help to improve the durability and thermal efficiency of turbine engines. Delamination of TBC owing to thermally grown metal oxides is a critical issue that needs periodical evaluation to ensure safety and effective maintenance for the financial benefits of industry. In this paper, a methodical approach using ultrasonic C-scan technique for quantitative evaluation of partial delamination area in TBC specimens was investigated. Preliminary studies were conducted using acoustic simulations and the experiments were carried out on a set of coin shaped TBC specimens prepared using plasma spray technique and isothermally degraded at 1100 °C for 25 h, 50 h, 100 h, and 150 h. Ultrasonic C-scans were performed using pulse echo technique with incident ultra sound radiation inclined normal to the surface of base metal of TBC system. Delamination maps of respective specimens were formulated from ultrasonic signals through proper signal processing and analysis techniques and the degree of delamination was evaluated with the help of existed mathematical model. The simulation results shows good agreement with the experimental data and this approach shows ability to estimate the degree of delamination from base metal surface.