University of Massachusetts Boston

About: University of Massachusetts Boston is a education organization based out in Boston, Massachusetts, United States. It is known for research contribution in the topics: Population & Health care. The organization has 6541 authors who have published 12918 publications receiving 411731 citations. The organization is also known as: UMass Boston.

Design of a Si-based lattice-matched room-temperature GeSn/GeSiSn multi-quantum-well mid-infrared laser diode.

Abstract: This paper presents modeling and simulation of a silicon-based group IV semiconductor injection laser diode in which the active region has a multiple quantum well structure formed with Ge(0.9)Sn(0.1) quantum wells separated by Ge(0.75)Si(0.1)Sn(0.15) barriers. These alloy compositions were chosen to satisfy three conditions simultaneously: a direct band gap for Ge(0.9)Sn(0.1), type-I band alignment between Ge(0.9)Sn(0.1) and Ge(0.75)Si(0.1)Sn(0.15,) and a lattice match between wells and barriers. This match ensures that the entire structure can be grown strain free upon a relaxed Ge(0.75)Si(0.1)Sn(0.15) buffer on a silicon substrate - a CMOS compatible process. Detailed analysis is performed for the type I band offsets, carrier lifetime, optical confinement, and modal gain. The carrier lifetime is found to be dominated by the spontaneous radiative process rather than the Auger process. The modal gain has a rather sensitive dependence on the number of quantum wells in the active region. The proposed laser is predicted to operate at 2.3 μm in the mid infrared at room temperature.

How Patient Centered Are Medical Decisions?: Results of a National Survey

Abstract: Importance Informing and involving patients in their medical decisions is increasingly becoming a standard for good medical care, particularly for primary care physicians. Objective To learn how patients describe the decision-making process for 10 common medical decisions, including 6 that are most often made in primary care. Design A survey of a national sample of adults 40 years or older who in the preceding 2 years had either experienced or discussed with a health care provider 1 or more of 10 decisions: medication for hypertension, elevated cholesterol, or depression; screening for breast, prostate, or colon cancer; knee or hip replacement for osteoarthritis, or surgery for cataract or low back pain. Setting Adults living in households in the United States in 2011. Participants A national sample of adults drawn from a probability sample–based web panel developed by Knowledge Networks. Main Outcomes and Measures Patients’ perceptions of the extent to which the pros and cons were discussed with their health care providers, whether the patients were told they had a choice, and whether the patients were asked for their input. Results Responses were obtained from 2718 patients, with a response rate of 58.3%. Respondents reported much more discussion of the pros than the cons of all tests or treatments; discussions about the surgical procedures tended to be more balanced than those about medications to reduce cardiac risks and cancer screening. Most patients (60%-78%) said they were asked for input for all but 3 decisions: medications for hypertension and elevated cholesterol and having mammograms (37.3%-42.7%). Overall, the reported decision-making processes were most patient centered for back or knee replacement surgery and least for breast and prostate cancer screening. Conclusions and Relevance Discussions about these common tests, medications, and procedures as reported by patients do not reflect a high level of shared decision making, particularly for 5 decisions most often made in primary care.