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Biomedical subjects

J P McGuire

Publications and source records attributed to J P McGuire.

9 recordsLinked to original sources
PubMed2004

Spin accumulation in forward-biased MnAs/GaAs Schottky diodes.

We describe a new means for all-electrical generation of spin polarization in semiconductors. In contrast with spin injection of electrons by tunneling through a reverse-biased Schottky barrier, we observe accumulation at the metal-semiconductor interface of forward-biased ferromagnetic Schottky diodes, which is consistent with a theory of spin-dependent reflection off the interface. Spatiotemporal Kerr microscopy is used to image the electron spin and the resulting dynamic nuclear polarization that arises from the nonequilibrium carrier polarization.

Journal Article↗
PubMed2002

Spin polarization of semiconductor carriers by reflection off a ferromagnet.

We present a theory of generation or alteration of the electron spin coherence and population in an n-doped semiconductor by reflection at the interface with a ferromagnet. The dependence of the spin reflection on the Schottky barrier height and the doping concentration in the semiconductor was computed for a generic model. The theory provides an explanation for the spontaneous electron spin coherence and nuclear polarization in the semiconductor interfaced with a ferromagnet and associated phenomena recently observed by time-resolved Faraday rotation experiments. The study also points to an alternative approach to spintronics different from spin injection.

Journal Article↗
PubMed1995

Sleep and psychological characteristics of children on a psychiatric inpatient unit.

OBJECTIVE: To assess the association of objective measures of sleep-wake patterns and psychological status and abuse history of children hospitalized in a psychiatric inpatient unit. METHOD: Thirty-nine inpatient children participated in the study. They were monitored for one to three consecutive nights with miniature wrist activity monitors for objective assessment of sleep-wake patterns. In addition, a thorough psychiatric and psychosocial assessment was completed with each child and the parents. RESULTS: Children's self-ratings of depression, hopelessness, and low self-esteem were significantly correlated with objective sleep measures indicating poorer sleep quality. No significant correlations between intelligence scores and sleep measures were found. Nonabused and sexually abused children had better sleep quality than physically abused children. CONCLUSIONS: Sleep quality during hospitalization is strongly associated with self experiences of depression, hopelessness, and low self-esteem in children with severe behavior disorders.

Adolescent↗
PubMed1994

Somatic, cognitive and emotional characteristics of abused children in a psychiatric hospital.

A systematic review of medical records of one hundred consecutive admissions to a children's psychiatric inpatient unit was conducted to assess specific somatic, cognitive and emotional characteristics that distinguish sexually abused children from other hospitalized children. Sexually abused children were characterized by: a lower performance IQ, higher incidence of parasomnia prior to admission, longer length of hospital stay, and comparatively small physical stature.

Adolescent↗
PubMed1994

Comparison of forced-air patient warming systems for perioperative use.

BACKGROUND: Perianesthetic hypothermia is common and produces several complications, including postoperative shivering, decreased drug metabolism and clearance, and impaired wound healing. Forced-air warming transfers more than 50 W to the body and is an efficient method for either preventing or reversing decreases in core temperature. METHODS: The authors compared the efficacy of four complete forced-air warming systems: (1) Bair Hugger 250/PACU Patient Warming System with 300 Warming Cover (Augustine Medical, Eden Prairie, MN); (2) Thermacare TC1000 Power Unit with TC1050 Comfort Quilt (Gaymar Industries, Orchard Park, NY); (3) WarmAir 130 Hypothermia System with 140 Warming Tube (Cincinnati Sub-Zero Products, Cincinnati, OH); and (4) WarmTouch 5000 Patient Warming System and 503-0810 CareQuilt (with the connecting hose compressed [short] and extended [long]) (Mallinckrodt Medical, St. Louis, MO). Six minimally clothed male volunteers were studied supine in a 24.5 degrees C environment. Cutaneous heat flux and skin temperature was measured at 14 area-weighted sites using thermal flux transducers. After 20-min control periods, volunteers were warmed for 40 min in each condition. A cotton blanket was placed over each cover. Power units were placed at the foot end of the bed, started cold, and set at maximum temperature and flow settings. All units reached maximum efficiency within 20 min. RESULTS: Total heat transfer with the Bair Hugger system (95 +/- 7 W) was greater (P < 0.05) than with WarmTouch (short hose 81 +/- 6 W and long hose 68 +/- 8 W), Thermacare (61 +/- 5 W), and WarmAir (38 +/- 6 W) systems. Each cover also was tested on a common power unit (Bair Hugger 200). Total heat transfer was greater (P < 0.05) with the Warming Cover (Bair Hugger) (88 +/- 8 W), followed by the Comfort Quilt (Thermacare) (56 +/- 6 W), CareQuilt (WarmTouch) (50 +/- 7 W), and the Warming Tube (WarmAir) (43 +/- 6 W). CONCLUSIONS: The advantages of the Bair Hugger system and Warming Cover are evident in areas that are important for heat transfer from the periphery to the body core (chest, axilla, abdomen, and upper legs).

Adult↗
PubMed1980

Prediction of self-disclosure from objective personality assessment techniques.

Prior theory and research have suggested that self-disclosure may have a curvilinear relationship with psychological disturbance. The present study investigated the hypothesis using the CPI, MMPI, and Bipolar Psychological Inventory and employing Ss (N = 28) from a correctional institution. Analyses involved correlational, multiple regression and discriminant analysis techniques. The results offer partial support for the hypothesis and add substantially to the external validity of prior research.

Humans↗