Biomedical subjects

Matthew Comstock

Publications and source records attributed to Matthew Comstock.

3 recordsLinked to original sources

PubMed2006

Absolute orientation of molecules at interfaces.

A method to determine the absolute orientation of molecules at liquid interfaces by sum frequency generation (SFG) is reported. It is based on measurements of the orientations of two nonparallel vibrationally active chromophores in the molecule of interest combined with a rotation matrix formulation to obtain the absolute molecular orientation. We chose m-tolunitrile, a planar molecule adsorbed to the air/water interface, as a proof-of-method experiment. Quantitative analysis of different polarization sum frequency intensities facilitate unique peak assignments of the methyl and nitrile groups of m-tolunitrile. The SFG analysis of the measurement yields a nitrile group tilting at 53 degrees to the surface normal, and the C3 axis of the methyl group is almost upright at 23 degrees with respect to the surface normal. Using a rotation matrix formulation, we found that the angle between the surface plane and the m-tolunitrile molecular plane is 70 degrees.

Journal Article↗

PubMed2005

Certificate-of-Need regulation in outpatient surgery and specialty care: implications for plastic surgeons.

For plastic surgeons, independent development of outpatient surgical centers and specialty facilities is becoming increasingly common. These facilities serve as important avenues not only for increasing access and efficiency but in maintaining a sustainable, competitive specialty advantage. Certificate of Need regulation represents a major hurdle to plastic surgeons who attempt to create autonomy in this fashion. At the state level, Certificate of Need programs were initially established in an effort to reduce health care costs by preventing unnecessary capital outlays for facility expansion (i.e., managing supply of health care resources) in addition to assisting with patient safety and access to care. The purpose of this study was to examine the effect of Certificate of Need regulations on health care costs, patient safety, and access to care and to discuss specific implications of these regulations for plastic surgeons. Within Certificate of Need states, these regulations have done little, if anything, to control health care costs or affect patient safety. Presently, Certificate of Need effects coupled with recent provisions in the Medicare Modernization Act banning development of specialty hospitals may restrict patient access to ambulatory surgical and specialty care. For the plastic surgeon, these effects not only act as an economic barrier to entry but can threaten the efficiencies gained from providing surgical care in an ambulatory setting. An appreciation of these effects is critical to maintaining specialty autonomy and access to fiscal policy.

Certificate of Need↗

PubMed2004

Use of coherent control methods through scattering biological tissue to achieve functional imaging.

We test whether coherent control methods based on ultrashort-pulse phase shaping can be applied when the laser light propagates through biological tissue. Our results demonstrate experimentally that the spectral-phase properties of shaped laser pulses optimized to achieve selective two-photon excitation survive as the laser pulses propagate through tissue. This observation is used to obtain functional images based on selective two-photon excitation of a pH-sensitive chromophore in a sample that is placed behind a slice of biological tissue. Our observation of coherent control through scattering tissue suggests possibilities in multiphoton-based imaging and photodynamic therapy.

Animals↗