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Biomedical subjects

J M Bowman

Publications and source records attributed to J M Bowman.

At least 19 recordsLinked to original sources
PubMed2006

Signatures of H2CO photodissociation from two electronic states.

Even in small molecules, the influence of electronic state on rotational and vibrational product energies is not well understood. Here, we use experiments and theory to address this issue in photodissociation of formaldehyde, H2CO, to the radical products H + HCO. These products result from dissociation from the singlet ground electronic state or the first excited triplet state (T1) of H2CO. Fluorescence spectra reveal a sudden decrease in the HCO rotational energy with increasing photolysis energy accompanied by substantial HCO vibrational excitation. Calculations of the rotational distribution using an ab initio potential energy surface for the T1 state are in very good agreement with experiment and strongly support dominance of the T1 state in the dynamics at the higher photolysis energies.

Electrochemistry↗
PubMed2004

The roaming atom: straying from the reaction path in formaldehyde decomposition.

We present a combined experimental and theoretical investigation of formaldehyde (H2CO) dissociation to H2 and CO at energies just above the threshold for competing H elimination. High-resolution state-resolved imaging measurements of the CO velocity distributions reveal two dissociation pathways. The first proceeds through a well-established transition state to produce rotationally excited CO and vibrationally cold H2. The second dissociation pathway yields rotationally cold CO in conjunction with highly vibrationally excited H2. Quasi-classical trajectory calculations performed on a global potential energy surface for H2CO suggest that this second channel represents an intramolecular hydrogen abstraction mechanism: One hydrogen atom explores large regions of the potential energy surface before bonding with the second H atom, bypassing the saddle point entirely.

Journal Article↗
PubMed2004

Experimental and theoretical study of the infrared spectra of BrHI- and BrDI-.

Gas phase vibrational spectra of BrHI- and BrDI- have been measured from 6 to 17 microm (590-1666 cm(-1)) using tunable infrared radiation from the free electron laser for infrared experiments in order to characterize the strong hydrogen bond in these species. BrHI-.Ar and BrDI-.Ar complexes were produced and mass selected, and the depletion of their signal due to vibrational predissociation was monitored as a function of photon energy. Additionally, BrHI- and BrDI- were dissociated into HBr (DBr) and I- via resonant infrared multiphoton dissociation. The spectra show numerous transitions, which had not been observed by previous matrix studies. New ab initio calculations of the potential-energy surface and the dipole moment are presented and are used in variational ro-vibrational calculations to assign the spectral features. These calculations highlight the importance of basis set in the simulation of heavy atoms such as iodine. Further, they demonstrate extensive mode mixing between the bend and the H-atom stretch modes in BrHI- and BrDI- due to Fermi resonances. These interactions result in major deviations from simple harmonic estimates of the vibrational energies. As a result of this new analysis, previous matrix-isolation spectra assignments are reevaluated.

Journal Article↗
PubMed2000

Chemistry. Beyond platonic molecules.

Molecular motion is influenced by quantum mechanics, which thus affect molecular properties such as their reactivity and the ease with which they isomerize. In his Perspective, Bowman describes recent theoretical advances that allow accurate quantum mechanical calculation of molecular motions for ever larger systems.

Journal Article↗
PubMed1999

Differences in African American and white women with myocardial infarction: history, presentation, diagnostic methods, and infarction type.

BACKGROUND: Despite overall declining death rates from cardiovascular disease, the number of women dying of cardiovascular disease increases each year, with substantially higher rates in African American women than in white women. OBJECTIVE: To investigate differences in presentation, diagnostic method, and type of infarction between African American and white women with myocardial infarction. METHODS: Chart review of all women with discharge diagnosis of myocardial infarction. RESULTS: No significant differences were found between African American and white women in admitting diagnosis, diagnostic methods, or type of infarction. At the time of admission, 2 medical history variables, stroke and hypertension, differed significantly between African American and white women (P = .027 and P = .002, respectively). CONCLUSIONS: Healthcare professionals must be aware of possible racial differences in medical history, signs and symptoms, and prognosis when assessing patients and planning interventions. Studies with larger samples are needed to confirm these findings on African American and white women with myocardial infarction.

Black or African American↗
PubMed1998

Factors that influence patient satisfaction in the emergency department.

This descriptive correlation study examined the satisfaction levels of urgent and nonurgent patients in relation to nursing care, the emergency department (ED) environment, ancillary services, and information received. The sample consisted of 28 subjects, with the majority of patients being very satisfied with nursing care. The primary area of concern was information about the length of waiting time. The satisfaction levels of ED patients with the care they receive has become increasingly important in today's health care environment. ED nurses play an important role in ensuring that patients are satisfied and receive quality care.

Adult↗
PubMed1995

Fetofetal transfusion in triplets.

A case of fetofetal transfusion syndrome (FFTS) in a monochorionic triplet pregnancy, in which all three fetuses shared a common circulation, is reported. All babies were born alive, although two died within two days of delivery. This case highlights the problem of FFTS with accompanying high perinatal morbidity and mortality in naturally occurring monochorionic triplet gestations.

Adult↗
PubMed1994

Neonatal portal vein thrombosis successfully treated by regional streptokinase infusion.

We report a case of portal vein thrombosis (PVT) in a term neonate following an exchange transfusion through an umbilical vein catheter which was left in situ for 16 h after the transfusion. The baby made a complete recovery after successful thrombolysis with regional streptokinase infusion. To our knowledge, this is the first reported case of a PVT following an indwelling portal venous catheter left in situ with complete resolution following thrombolysis with regional streptokinase infusion.

Humans↗
PubMed1994

Perception of surgical pain by nurses and patients.

A descriptive study of postoperative patients was conducted to determine if there were any differences in the pain ratings of nurses and patients using a 10-centimeter graphic rating scale (GRS). The sample consisted of 16 patients: 3 males and 13 females. There were 13 nurses: 54% R.N.s and 46% L.P.N.s. When patients requested pain medication, both the patient and nurse were asked independently to indicate their perception of the patient's pain on the scale. The mean patient score on the GRS was 7.59; the mean for nurses was 4.59. At test revealed a significant difference between the nurses' and patients' pain ratings (t = 4.22, p = .0002). Based on this study, there is further need to examine assessment of the patient and the perceptions of the nurse and patient.

Adult↗
PubMed1994

Attitudes of baccalaureate nursing students in one school toward acquired immune deficiency syndrome.

The purpose of this descriptive study was to gather information about the attitudes of nursing students toward Acquired Immune Deficiency Syndrome (AIDS) and to determine if there was a relationship between demographic variables and the attitudes expressed. In this study the AIDS Attitude Scale developed by Shrum, Turner, and Bruce (1989) was administered to baccalaureate nursing students. The scale contained 54 items using a five-response scale and included six demographic variables. The results indicated that this sample had a positive attitude toward AIDS (mean = 73.58). Personally knowing someone with AIDS and level of knowledge of AIDS were found to significantly affect one's attitude toward AIDS. The findings of this study can assist nurse educators in planning appropriate content for AIDS education.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Fetomaternal hemorrhage following funipuncture: increase in severity of maternal red-cell alloimmunization.

OBJECTIVE: To determine the prevalence of fetomaternal transplacental hemorrhage after funipuncture and its effect on maternal red-cell alloantibody levels. METHODS: The prevalence and size of transplacental hemorrhages at the Health Sciences Centre were studied in two groups of patients: 174 women who were not alloimmunized or were carrying fetuses whose red cells were negative for the antigen to which they were immunized, and 122 women who were alloimmunized and carrying fetuses whose red cells were positive for the antigen to which they were immunized. In the alloimmunized group with affected fetuses, we surveyed the incidence of maternal antibody increase in titer by two or more doubling dilutions and the Rh(D) antibody increase (in microgram/mL of serum) of more than 50% after funipuncture. RESULTS: One hundred of the 174 women (57.5%) in the nonimmunized group and 69 of the 122 women (56.6%) in the immunized group had evidence of transplacental hemorrhages ranging in volume from 0.03 mL to greater than 5 mL of fetal red blood cells. In the latter group, antibody titer increases of 2 to 9 and doubling dilutions occurred in 37 of 74 women (50%) in whom such measurements were carried out. Increases of anti-D exceeding 50% occurred in 44 of 53 women (83%) in whom quantitative measurements were assayed. CONCLUSION: Funipuncture carries a high risk of fetal transplacental hemorrhage. In the immunized woman carrying an antigen-positive fetus, this will increase the level of her antibody and probably increase the severity of hemolytic disease in her fetus. In alloimmunized women, funipuncture should rarely be carried out to determine the fetal antigen status. Serial amniocenteses combined with careful serial ultrasound observation of the fetus are safer. Funipuncture should not be done in alloimmunized women before the cord vessels are of adequate size to allow immediate intravascular fetal transfusion, if required.

Blood Group Antigens↗
PubMed1994

Massive fetomaternal hemorrhage: Manitoba experience.

OBJECTIVE: To determine the incidence, size, and outcome of spontaneous massive fetomaternal transplacental hemorrhage in Manitoba. METHODS: The Kleihauer maternal-fetal screening records at the Rh Laboratory were reviewed for the period October 1970 to December 1992. Rh Laboratory correspondence for the 7-year period ending December 31, 1992, was reviewed to determine those instances of fetomaternal transplacental hemorrhage for which there was knowledge regarding fetal and neonatal outcome. RESULTS: Twenty-seven of 30,944 Rh-negative women undergoing routine Kleihauer screening at delivery had fetomaternal transplacental hemorrhages of at least 80 mL of fetal blood (incidence one in 1146 pregnancies); in 11 of the 27, the hemorrhages were 150 mL of blood or more (one in 2813 pregnancies). In non-routinely screened, selected maternal blood samples, sent because of unexplained fetal distress, fetal death, or neonatal anemia, 36 had evidence of fetomaternal transplacental hemorrhage of at least 80 mL of blood, 28 of which were in the 7-year period ending December 31, 1992 (one in 3893 pregnancies). Of these 28, 25 had hemorrhages of at least 150 mL of blood (one in 4360 pregnancies). Ascertainment of fetomaternal transplacental hemorrhage of 150 mL or more in women referred because of fetal or neonatal problems was 2813/4360 x 100 = 64.5%. Twenty-six cases in the final 7-year period had information regarding perinatal outcome. The incidence of adverse outcomes following massive fetomaternal transplacental hemorrhage was 46% (12 of 26). There were ten perinatal deaths, one infant death at 6 months, and one infant with spastic quadriplegia. CONCLUSIONS: Massive fetomaternal transplacental hemorrhage is uncommon but not rare, and subsequent adverse outcomes are common. A high index of suspicion with prompt investigation and appropriate management may improve the perinatal outcome following massive fetomaternal transplacental hemorrhage.

Female↗
PubMed1993

Maternal CW alloimmunization.

The Winnipeg Rh Laboratory has reviewed its experiences with maternal CW alloimmunization. From September 24, 1956, to March 31, 1992, 12 women with significant CW alloimmunization underwent 18 pregnancies. In 3 (4 pregnancies) the antibody, despite its strength, was 'naturally occurring' (i.e. there was no known exposure to CW-positive red cells). The remaining 9 women (14 pregnancies) had CW-positive husbands. Two had CW-negative babies and a third infant, probably CW negative, was stillborn and macerated at 43 weeks gestation. Eleven babies were CW positive and had hemolytic disease of the newborn (HDN), with antiglobulin-positive red cells. Five did not require treatment; 2 needed phototherapy only, and 4 (born between 1956 and 1963) required exchange transfusions. No anti-CW screening was carried out until 1977; thereafter it was sporadic, 11 of 51 screening red cells being CW positive in the 39-month period ending March 31st, 1992. From November 1, 1977, to March 31, 1992, 24 women (30 pregnancies, 31 conceptuses) with insignificant anti-CW alloantibodies were identified. Extrapolating these figures to the entire period from September 24, 1956, to March 31, 1992, we estimate that at least 430 women (at least 573 pregnancies) were CW alloimmunized, most of the antibodies being 'naturally occurring'. Only 2% of the conceptuses were CW positive and affected; none were severely affected. Anti-CW is relatively common, occurring in about 1 pregnant Manitoban woman in 1,100. On very rare occasions (11 times in Manitoba in 36 years and 5 months) anti-CW HDN occurs which, although not severe, may end in kernicterus with brain damage or neonatal death unless it is detected promptly and treated appropriately.

Coombs Test↗
PubMed1992

Severe anti-C hemolytic disease of the newborn.

OBJECTIVE: Because of referral of a C-alloimmunized pregnant woman with a previous hydropic death whose fetus survived after four intraperitoneal transfusions, prevalence and severity of anti-C hemolytic disease of the newborn were investigated. STUDY DESIGN: The numbers of C- or Ce-alloimmunized pregnancies in Manitoban women and their outcome for the 28-year period ending Oct. 31, 1990, were reviewed. The literature relating to C or Ce alloimmunization from 1944 to 1990 was surveyed. RESULTS: In Manitoba for the period reviewed there were 120 pregnancies in 80 C- or Ce-alloimmunized women. Twenty-two ended in abortion and two in fetal death unrelated to anti-C or anti-Ce. Of the remaining 96, 33 fetuses of 32 pregnancies were affected but only eight (6.7%) required treatment after birth. None were severely affected. In the literature there are only three other reported deaths from C or Ce hemolytic disease; two of the three may have been the same patient. The prevalence of C or Ce alloimmunization reported in various series, including our own, ranged from 8.7 to 185 per 100,000 pregnancies. CONCLUSIONS: Because on rare occasions, C or Ce alloimmunization can cause severe hemolytic disease, criteria for investigative measures such as amniocentesis or cordocentesis do not differ from the criteria for instituting these measures in Rho (D)-alloimmunized pregnancies.

Erythroblastosis, Fetal↗