Myocardial Infarction in a Young Man due to a Hypoplastic Coronary Artery

Hypoplastic coronary artery disease (HCAD) is a rare condition that may lead to myocardial infarction (MI) and sudden death. We discovered HCAD in a young man who developed chest pain after heavy drinking and who was found to have suffered an MI. His ECG showed ST-segment elevation with Q waves in the anterior leads, and echocardiography revealed apical dyskinesia with moderate left ventricular (LV) dysfunction. Coronary angiography showed hypoplasia of the left anterior descending (LAD) artery. 99mTc-tetrofosmin-gated myocardial perfusion scintigraphy showed a large, fixed perfusion defect in the anteroseptal and apical segments. Sixty-four-slice cardiac CT and cardiac MR imaging demonstrated thinning of the apical wall with calcification and delayed enhancement, supporting the diagnosis of long-standing MI. The patient was discharged symptom-free on medication for ischemic heart failure two weeks after admission. Although HCAD is very uncommon, it should be considered in children and young adults who suffer MI or sudden cardiac death

A Systems Approach to Optimize the Operation of a Refrigeration Unit at a Chemical Plant

This paper focuses on the ongoing system level analysis and the optimization results of two steamturbine driven refrigeration units at the Dow Chemical company Peroxymerics (PXC) plant located at St. Charles Operations in Hahnville, LA. Six-sigma has been accepted as a corporate-wide philosophy at the Dow Chemical Company, and this methodology was applied to this refrigeration system optimization at the plant. Process refrigeration at the plant comprises of two individual systems that operate at different temperature levels and serve a myriad of process loads as well as provide chilled water for the plant. The total plant capacity is ~6,500 refrigeration tons and has a total charge of 225,000 lbs of refrigerant - R134a. Two steam turbines drive the refrigerant compressors. The utility cost structure is interlaced with costs and credits for the supply and return steam to the plant headers. As a first step towards a systems approach for optimization of the refrigeration unit operation, Dow Chemical Company contracted with Hudson Technologies to undertake a feasibility study. After the projects were completed, operational data was then collected and analyzed to quantify the cost savings and level of optimization. Trending certain key parameters indicated ongoing performance and closely monitored system degradation