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Biomedical subjects

A J Dobson

Publications and source records attributed to A J Dobson.

At least 37 records · Page 2Linked to original sources

C-H...O interactions in dimethyl 6,6'-dimethoxy-3,3',5,5'-tetramethylbiphenyl-2,2'-dicarboxylate.

The title compound, C22H26O6, crystallized in the centrosymmetric space group Pbcn with half of the molecule as the asymmetric unit (the molecular symmetry is 2). The H atoms of each of the four methyl groups in the asymmetric unit are disordered over two sites. Nine leading C-H...O interactions are present, with H...O distances ranging from 2.50 to 2.87 A and C...O distances ranging from 3.157 (3) to 3.567 (3) A. The various interaction chains from a three-dimensional network. The intramolecular angle between the biphenyl ring planes (twist angle) is 71.3 (1) degree.

Benzoates↗

Hydrogen bonding in quinolinium-4-carboxylate trihydrate.

The previously undescribed title substance, C10H7NO2.-3H2O, crystallized in the centrosymmetric space group P1 with one zwitterionic organic molecule and three water molecules in the asymmetric unit. One N-H...O and six O-H...O hydrogen bonds are present in this structure, with donor-acceptor distances ranging from 2.607(2) to 2.931(3) A. The H atoms in these hydrogen bonds are ordered. The hydrogen bonds generate a two-dimensional network. Structural comparisons are made with quinolinium-4-carboxylate dihydrate.

Crystallization↗

Hydrogen bonding in quinolinium-4-carboxylate dihydrate.

The title acid, C10H7NO2.2H2O, crystallized in the non-centrosymmetric space group Cc with one zwitterionic organic molecule and two water molecules in the asymmetric unit. One N-H...O and four O-H...O hydrogen bonds are present in this structure, with donor-acceptor distances ranging from 2.688 (2) to 2.852 (3) A. These hydrogen bonds generate a three-dimensional network. Structural comparisons are made with anhydrous quinoline-4-carboxylic acid.

Crystallography, X-Ray↗

Hydrogen bonding in 4-aminohippuric acid.

The title acid, C9H10N2O3, crystallized in the non-centrosymmetric space group P2(1)2(1)2(1) with one molecule in the asymmetric unit. Four hydrogen bonds occur whose donor-acceptor distances are: O1...O3 2.630 (2), N1...O3 3.090 (2), N2...O1 3.099 (2), and N2...O2 3.022 (2) A, and whose angles fall in the range 163 (2)-173 (2) degrees. The H atoms in these bonds are ordered. Cyclic hydrogen-bonded dimers are not formed; through second-level graphs, only hydrogen-bonded chains occur. These form a strongly three-dimensional array of hydrogen bonds. The dihedral angle between the core plane and the carboxyl plane is 54.8 (2) degrees, and between the core plane and the plane of the amino group, 34 (1) degree. The structure is compared with a previous determination by Chakrabarti & Dattagupta [Z. Kristallogr. (1993), 207, 53-58] and with the structure of the parent molecule, hippuric acid.

Crystallography, X-Ray↗

Hydrogen bonding in 4,4',6,6'-tetramethyl-biphenyl-2,2'-dicarboxylic acid.

The title compound, C18H18O4, crystallizes in the centrosymmetric space group P2(1)/c, with two molecules in the asymmetric unit. Each of the four independent carboxylic H atoms is ordered, and each participates in hydrogen bonding. The OD...OA distances in the hydrogen bonds are 2.598 (3), 2.608 (3), 2.652 (3) and 2.641 (3) A. Two cyclic hydrogen-bonded dimers are found, neither occurring about a center of symmetry; each, however, occurs about a pseudo-center. Numerous hydrogen-bonded chains, all propagating along [010], are also present. The biphenyl twist angles are 88.4 (2) and 87.5 (2) degrees. Structural comparisons are made with the structures of the 'parent' compound, diphenic acid, and its 4,4'- and 6,6'-dimethyl derivatives.

Benzoates↗

6,6'-Dimethoxy-3,3',5,5'-tetramethylbiphenyl-2,2'-dimethanol.

The title compound, C20H26O4, crystallized in the centrosymmetric space group P21/c with a single molecule as the asymmetric unit. The two hydroxyl-H atoms are ordered and are involved in hydrogen bonds whose OD...OA distances are 2.807 (2) and 2.805 (2) A; one of these bonds is intramolecular. The intramolecular dihedral angle between the ring planes (twist angle) is 87.3 (1) degree.

Benzyl Alcohols↗

Changing patterns of coronary heart disease in the hunter region of New South Wales, Australia.

A population-based observational study of men and women aged 35-69 years in the Hunter Region of New South Wales, Australia, was conducted to assess the impact of risk-factor modification and increased drug therapy on the trends in major coronary events and case fatality. From 1985 to 1993, there were 3006 coronary deaths and 6450 nonfatal major coronary events. Rates of death and nonfatal myocardial infarction declined, but there was an increase in hospital admissions for prolonged chest pain. Reductions in cigarette smoking, diastolic blood pressure, total cholesterol, and increased use of aspirin can fully explain the 3.3% (95% confidence interval [CI] 2.4, 4.2) average annual reduction in rates of major coronary events for men and the 4.1% (95% CI 2.7, 5.5) reduction for women. In contrast, increased use of aspirin, beta-blockers, fibrinolytic therapy, and angiotensin-converting enzyme inhibitors explain less than half of the 8.9% (95% CI 5.9, 11.8) and 6.9% (95% CI 2.7, 10.9) average annual reduction in case fatality in hospital for men and women, respectively. These trends suggest a decline in severity of coronary heart disease consistent with reductions in risk-factor levels and improved acute medical treatment.

Adult↗

Women's Health Australia: on the progress of the main cohort studies.

More than 41,000 women aged 18-23, 45-50, and 70-75 years in 1996 are participating in the Australian Longitudinal Study on Women's Health (Women's Health Australia). Baseline surveys were conducted for all three cohorts in 1996, and the first follow-up survey of the mid-age group in 1998 has achieved a response rate exceeding 90%. The main findings so far reflect the large differences in the life experiences of the three cohorts. The young women report high levels of stress. The physical and mental health of those with young children is worse than for those without children, but confounding by sociodemographic characteristics may account for the differences. Two thirds of young women in the healthy weight or underweight range would like to weigh less, and early onset of dieting is associated with poorer physical and mental health. Most of the women in the mid-age group have multiple roles--in paid work, home duties, and caring for children and other dependents. The potential of the study to investigate the long-term impact of such busy lives on health outcomes is considerable. At this stage, the main health issues for these women relate to tiredness, weight gain, and menopause. The older cohort presents a picture of positive aging. These women are heavier users of health services than the mid-age and younger women, and they are also more satisfied with these services. Although their physical health is poorer, their mental health is better, and they report less stress than women in the other two cohorts. The follow-up survey of this group, planned for 1999, will focus on the coping strategies used by these women. An overall goal of the project is to understand the interactions among social roles, life events, and women's health in order to provide a basis for improved health policies and services. Analysis of these interactions, which relies on both quantitative and qualitative data, poses many challenges that will be addressed as the longitudinal data become available.

Adult↗

9H-fluorene-2-carboxaldehyde.

The title compound, C14H10O, crystallized in the centrosymmetric space group P2(1)/c with a single molecule in the asymmetric unit. The C-H...O interaction having the shortest C...O distance involves the ring-bridging C9 atom and one of its H atoms, and results in the formation of a cyclic dimer about a center of symmetry. The molecular core is nearly planar. The dihedral angle between the best-fit plane of the ring to which the aldehyde group is attached and the plane of the aldehyde group is 4.4 (9) degrees. In a number of respects the molecular disposition is similar to that previously determined for the geometrically similar dibenzofuran-4-carboxaldehyde molecule.

Aldehydes↗

Quinoline-4-carboxylic acid.

The title acid, C10H7NO2, crystallized in the centrosymmetric space group P2(1)/c with one molecule in the asymmetric unit. There is a single hydrogen bond. O-H...N, with a donor-acceptor distance of 2.596 (1) A. The carboxylic H atom is ordered. The dihedral angle between the best-fit quinoline core plane and the carboxyl plane is 45.9 (1) degrees. Structural comparisons are made with the closely related molecule 2-phenylquinoline-4-carboxylic acid.

Crystallography, X-Ray↗

(4R)-(-)-2-thioxothiazolidine-4-carboxylic acid (raphanusamic acid).

The title acid, C4H5NO2S2, crystallized in the noncentrosymmetric space group P2(1)2(1)2(1) with one molecule as the asymmetric unit. Two hydrogen bonds occur, namely, N--H...O, with a donor-acceptor distance of 2.850 (2) A, and O-H...S (resonance induced), with a donor-acceptor distance of 3.318 (2) A; both H atoms involved are ordered. These two types of bonds link a given molecule to four neighbors, the molecules linked being of space-group symmetry types 1 and 3, or 2 and 4. These two subsets of molecules alternate in layers along c. Three significant C-H...O interactions occur, one of which crosslinks the subsets just described to produce a three-dimensional network of linked molecules. The absolute structure is determined.

Crystallography, X-Ray↗

5-ammoniosalicylic acid chloride monohydrate.

The title compound, C7H8NO3+.Cl-.H2O, crystallized in the centrosymmetric space group P2(1)/c in an ionic form, the proton from HCl having been transferred to the amino N atom. The three H atoms on N, the H atom on the carboxyl group, the H atom of the hydroxyl group and the H atoms of the water molecule, all of which are involved in hydrogen bonding, are ordered. The eight 'best' hydrogen bonds have the following donor-acceptor distances: O...O 2.681 (2) and 2.598 (2); O...Cl 3.367 (1), 3.345 (2) and 3.156 (2); N...O 2.995 (2); N...Cl 3.173 (2) and 3.114 (2) A. In this structure, the acid cations are not linked directly to each other by hydrogen bonds, but are linked indirectly, via hydrogen bonds involving chloride ions and water molecules, into a three-dimensional network. Through basic second-level graphs, finite patterns substantially outnumber chains and rings.

Crystallography, X-Ray↗

5-aminoisophthalic acid hemihydrate.

The title acid, C8H7NO4.0.5H2O, crystallized in the centrosymmetric space group C2/c in a zwitterionic form (5-ammonioisophthalate), with the water molecule on a twofold axis. The three ammonio H atoms and the H atom on the remaining carboxyl group, which are involved in hydrogen bonding, are ordered. Three intermolecular N-H...O hydrogen bonds have N...O distances ranging from 2.762 (2) to 2.905 (2) A and N-H...O angles ranging from 155 (2) to 163 (2) degrees. Two intermolecular O-H...O hydrogen bonds have O...O distances of 2.536 (2) and 2.746 (2) A, and O-H...O angles of 178 (2) and 176 (2) degrees. A three-dimensional network of hydrogen bonds is present. Through basic second-level graphs involving acid-to-acid hydrogen bonds, chains are more numerous than rings.

Crystallography, X-Ray↗

8-Aminocaprylic acid.

The title acid, 8-aminooctanoic acid, C8H17NO2, crystallized in the centrosymmetric space group P2(1)/n in the zwitterionic form. The three H atoms involved in hydrogen bonding are ordered. The five intermolecular N-H...O hydrogen bonds have N...O distances ranging from 2.752 (2) to 3.258 (2) A and N-H...O angles ranging from 131 (2) to 165 (2) degrees. Each molecule is linked to six neighboring molecules by a total of ten hydrogen bonds. A complex network of hydrogen bonds ensues in which chains predominate.

Caprylates↗

DL-3-aminoisobutyric acid monohydrate.

The title acid, 3-amino-2-methylpropanoic acid monohydrate, C4H9NO2.H2O, crystallized in the centrosymmetric space group Pbca in the zwitterionic form. The three H atoms on N, which are involved in hydrogen bonding, are ordered. The three intermolecular N-H...O hydrogen bonds have N...O distances ranging from 2.758 (2) to 2.809 (2) A and N-H...O angles ranging from 149 (2) to 171 (1) degrees. The two intermolecular O-H...O hydrogen bonds have O...O distances 2.739 (2) and 2.755 (2) A, and O-H...O angles 170 (2) and 175 (2) degrees. Each acid molecule and its associated water molecule are directly hydrogen bonded to five acid molecules and two water molecules; the structure comprises two subsets of molecules which are not cross-linked by these hydrogen bonds. Through basic second-level graphs, approximately two-thirds of the hydrogen-bonding patterns are finite and one-third are chains; there is a single ring pattern, which occurs about a center of symmetry.

Aminoisobutyric Acids↗

Biphenyl-2-carboxylic acid: a layered structure.

The title acid, C13H10O2, crystallized in the centrosymmetric space group P2(1)/c with four molecules in the asymmetric unit. These four molecules form two pairs of cyclic hydrogen-bonded dimers of the usual sort, but these are not formed about centers of symmetry. The Odonor...Oacceptor distances in these hydrogen bonds are 2.660(3), 2.638(3), 2.676(3) and 2.634(3) A. The carboxylic H atoms and the carboxylic O atoms are ordered. The biphenyl twist angles range from 46.5(2) to 52.5(2) degrees. The dihedral angles between the carboxyl group planes and the planes of the rings to which they are attached range from 43.6(3) to 50.9(3) degrees. In the two latter respects, this structure differs appreciably from the structures of the other two biphenyl monocarboxylic acids. The structure is layered parallel to the ab plane.

Benzoates↗

Women's satisfaction with general practice consultations.

OBJECTIVE: To determine women's satisfaction with general practice services. DESIGN: Cross-sectional postal questionnaire conducted during April to September 1996 (part of the baseline survey of the Australian Longitudinal Study on Women's Health). PARTICIPANTS: Women aged 18-22 (n = 14,739), 45-49 (n = 14,013) and 70-74 (n = 12,941) years, randomly selected from the Medicare database, with oversampling of women from rural and remote areas. MAIN OUTCOME MEASURES: Frequency of use of general practice services; satisfaction with the most recent visit to a general practitioner (GP); prevalence of selected symptoms; preference for a female doctor. RESULTS: The most recent visit to a GP was rated overall as good, very good or excellent by more than 80% of women, with increasing levels of satisfaction with increasing age of the women. However, satisfaction was lower for waiting room time and cost of the visit. A third of the young and middle-aged women living in rural and remote areas were dissatisfied with the cost of the visit. Young women were more likely to prefer a female doctor, and many were dissatisfied with their GP's skills at explaining their problem and giving them a chance to give an opinion and ask questions. The most prevalent symptoms for all women included headaches and tiredness, and may were not satisfied with the health services available to help them deal with these symptoms. CONCLUSIONS: Australian women have high levels of satisfaction with GP consultations. However, more effective strategies may be needed to improve communication with younger women, and there is an unmet need for services to help all women deal with some common symptoms. Dissatisfaction with cost of services and women's preference for female doctors have implications for future health policy.

Adolescent↗

Complex network of hydrogen bonds in 3-aminopyrazole-4-carboxylic acid.

3-Aminopyrazole-4-carboxylic acid, C4H5N3O2, crystallized in the non-centrosymmetric space group P21 in the zwitterionic form. Intermolecular N--H...O hydrogen bonds with N...O distances of 2.768 (2) and 2.747 (2) A link molecules into two sets of chains propagating along [110] and [110]. The two sets of chains are crosslinked by strong hydrogen bonds. A complex network of hydrogen bonds ensues. There is a single intramolecular hydrogen bond. The pyrazole core is closely planar; the dihedral angle between the best-fit core planes of the molecules making up the two chains is 82.2 (1) degrees. The dihedral angles between the core plane and the planes of the carboxylate group and the amino group are in the region of 2 and 37 degrees, respectively.

Crystallization↗