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Biomedical subjects

B Chance

Publications and source records attributed to B Chance.

728 records · Page 41Linked to original sources
PubMedDate not supplied

Rabbit cornea stromal hydration measured with proton NMR spectroscopy.

The suitability of water proton spin-lattice relaxation time T1 as a measure of corneal dysfunction is investigated in this paper. Proton nuclear magnetic resonance measurements were performed on excised rabbit corneas using the saturation recovery method to determine the proton spin-lattice relaxation time T1. Both freshly excised and progressively swollen rabbit corneas were studied. The experimental results are consistent with a two compartment model of "bound" water and "free" water. This model results in a linear correlation between 1 / T1 (measured) and 1/corneal hydration. This correlation suggests that water proton T1 values can be used as an index of corneal dysfunction.

Animals↗
PubMedDate not supplied

A new spectroscopic approach to cardiac energy metabolism.

The optical characteristics of the hemoglobin-free perfused rat heart have been examined in detail. For dual-wavelength spectrophotometry, absorption pairs at 605-620 nm and 587-620 nm are found to be suited for the investigation of the oxidation-reduction changes of cytochrome aa3 and oxygenation-deoxygenation of myoglobin in cardiac tissue. Techniques by which the absorption changes of myoglobin and cytochrome aa3 can be measured during one cycle of contraction-relaxation are presented. The results demonstrate that, in the aerobic state, myoglobin is more oxygenated during the systolic and diastolic periods and deoxygenated in the resting period, whereas cytochrome aa3 is more reduced in the systole and diastole and oxidized in the resting period.

Aerobiosis↗
PubMedDate not supplied

Who me? Reduce hemorrhoids? It's not my job!

Hemorrhoids are a problem for many postpartum patients. A procedure for manually reducing hemorrhoids is outlined along with necessary patient teaching. This procedure is a nursing responsibility as long as the patient does not have other anorectal area trauma.

Female↗
PubMedDate not supplied

Physical and psychosocial side effects of antepartum hospital bed rest.

The purpose of this study was to describe the physical and psychosocial effects of antepartum hospital bed rest on pregnant women and to determine whether the symptoms exhibited differed from those exhibited by pregnant women not on bed rest. Women on complete bed rest (n = 10) had greater gastrocnemius muscle dysfunction, weight loss, and dysphoria than women on partial bed rest (n = 7) or no bed rest (n = 18). Separation from family was the greatest hospital stressor. Postpartum recovery from the side effects of bed rest was prolonged and included symptoms of muscular and cardiovascular deconditioning. The severity of side effects appeared to be directly related to the degree of severity restriction.

Activities of Daily Living↗
PubMedDate not supplied

Feasibility study of a single- and multiple-source near-infrared phase-modulation device for characterizing biologic systems.

Near-infrared (NIR) spectroscopy is an inexpensive and noninvasive optical method to characterize biologic and physiologic systems. Measurements of oxygen saturation in various organs, cytochrome oxidase concentration, and glucose concentration in tissue are examples of NIR spectroscopy applications. This instrument also has potential for diagnostic imaging by comparing the optical properties of a given point in tissue with those of the surrounding areas, e.g., tumor localization, hematoma detection, or deep vein thrombosis detection. Currently, NIR spectroscopy is available in three modalities: time-resolved spectroscopy (TRS), continuous-wave spectroscopy (CWS), and a phase-modulation device. This paper describes a single-source phase-modulation device and a multiple-source (in- and anti-phased) device and their application to system identification. The phase and intensity information for homogeneous systems is correlated with system and instrumental parameters. Phase and intensity changes resulting from the presence of one and two absorbers are illustrated. The sensitivity of in- and anti-phased phase-modulation devices (phased arrays) is demonstrated. The use of amplitude-modulated phased array for heterogeneity detection is described.

Computer Simulation↗