Polishing of CVD-Diamond Substrates Using Reactive Ion Etching

Multichip modules (MCM)have proved to be a viable packaging technology for achieving small size and high performance. By their nature, MCMs typically integrate multiple bare die into a module that can be the plastic or ceramic package. As a result, the MCMrequires an efficient mechanism for removing excess heat. Diamond with its excellent thermal conductivity, is the ideal choice as a substrate material for these applications. Chemical vapor deposited (CVD) diamond substrates makes possible the practical realization of a novel diamond based 3-D MCM. However, the diamond films grown by CVD technique are polycrystalline and have non-uniform filmroughness and randomly faceted crystals. These non-planar surfaces reduce the diamond\u27s thermal management efficiency. Therefore, itbecomes imperative that the asdeposited diamond films be polished for use inMCMs. Chemical assisted mechanical polishing (CAMP) technique has been developed at HiDEC,University of Arkansas. In this technique diamond is lapped against an alumina plate under a load in the presence of certain chemicals. Although CAMP technique reduces the lapping time considerably, stillnewer techniques must be developed to reduce polishing cost further. We are currently using reactive ion etching (RIE) to substantially reduce the polishing time. Preliminary studies using reactive ion etching showed etch rates of 500 - lOOOA/min at low pressures. These etched films showed a considerably higher polishing rate (using CAMP technique) than the nonetched films. Changes in the morphology and structure of the diamond films due to etching and polishing were characterized by scanning electron microscopy (SEM), Dektak profilometer and Raman spectroscopy. This paper presents a systematic study ofRIEand CAMP of CVD-diamond substrates

Fingertip digital thermal monitoring: a fingerprint for cardiovascular disease?

Cardiac Dysfunction and Arrhythmia

Increased accuracy in computed tomography coronary angiography; a new body surface area adapted protocol

Vascular Biology and Interventio

Coronary artery calcium screening: current status and recommendations from the European Society of Cardiac Radiology and North American Society for Cardiovascular Imaging

Current guidelines and literature on screening for coronary artery calcium for cardiac risk assessment are reviewed for both general and special populations. It is shown that for both general and special populations a zero score excludes most clinically relevant coronary artery disease. The importance of standardization of coronary artery calcium measurements by multi-detector CT is discussed

Aggressive presentation of streptococcus constellatus

The Streptococcus anginosus group (SAG) consists of three bacteria (Streptococcus intermedius, Streptococcus constellatus, and Streptococcus anginosus) that are known commensals of the upper respiratory, digestive, and reproductive tracts. While a rare occurrence, these bacteria have the capability of causing devastating pyogenic infections and ensuing abscess formations. It is often difficult to distinguish this group as a contaminant or the offending organism (as it is often cultured in respiratory specimens); therefore, it is important to understand the risk factors, clinical presentation, and diagnostic findings that can provide a more accurate picture to identify the organism. Published literature pertaining to the SAG group has rarely documented any invasive surgical intervention that was undertaken for treatment. We describe a case of a 59-year-old male who presented for persistent chest pain and profuse productive cough weeks after he was diagnosed with a left lower extremity deep vein thrombosis and right-sided pulmonary embolism. The patient was found to have a rapidly evolving Streptococcus constellatus right middle lobe lung abscess complicated by a right hemithorax empyema. Management included an exploration of the right chest, decortication, parietal pleurectomy, and partial excision of the right middle lobe. Subsequently, the patient completed four weeks of antibiotics with ertapenem

Comparison of best medical management with carotid intervention procedures in the prevention of stroke recurrence in patients with symptomatic internal carotid artery stenosis

Background: As per the current recommendations, carotid interventional procedures (carotid endarterectomy/carotid artery stenting) are considered superior to medical management in reducing the stroke recurrence in patients with symptomatic extracranial internal carotid artery (ICA) stenosis. Objective: The objective of this study is to compare the best medical management with carotid interventional procedures in the prevention of stroke recurrence in the patients with symptomatic extracranial ICA stenosis. Materials and Methods: This was a parallel, prospective, two-arm, open-label, observational study. Participants were selected consecutively and prospectively among patients from Outpatient and Inpatient Departments of Neurology at Nizam's Institute of Medical Sciences, Hyderabad, Telangana, India. The study period was from January 2012 to December 2017. Results: Of 150 patients with symptomatic extracranial ICA stenosis of ≥50%, 100 preferred best medical management (m = 75, f = 25) and 50 (m = 37, f = 13) opted for carotid intervention. The mean age of the patient cohort was 59.8 ± 12.7. Follow-up was done at regular intervals from 3 months to 1 year. In the medical group, the recurrence occurred in 10 patients; 4 (40%) within 6 months, 5 (50%) within 6–12 months, and 1 (10%) after 1 year. In the intervention group, the recurrence occurred in 6 patients; 5 (83%) within the first 6 months and 1 (17%) within 6–12 months. Conclusions: Overall, there was no statistically significant difference in the rate of recurrence between the best medical management and the carotid interventional procedures