Progress in the Preparation of Aluminum Nitride Substrates from Bulk Crystals

Large (11-mm diameter) single-crystal AlN boules have been prepared using sublimationrecondensation growth. X-ray topography shows that substrates prepared from those boules have a dislocation density of less than 500 cm-2, while the central region of these substrates was nearly dislocation-free. Rocking curves of less than 10 arcsecs have been obtained indicating the high quality of these crystals. The AlN substrates have been used to growth an AlGaN/AlN multiquantum well structure with excellent crystalline quality and with photoluminescence peaked at around 260nm. In addition, a UV LED with emission wavelength at 360nm has been fabricated. This is the first operating opto-electronic device demonstrated on an AlN substrate.

Electronic excitations in B12As2 and their temperature dependence by vacuum ultraviolet ellipsometry

The dielectric response function of epitaxial B(12)As(2) films on 4H-SiC was determined at room temperature and at 10 K in the spectral region of 3.6-9.8 eV, i.e., in the vacuum ultraviolet (VUV) spectral region, by synchrotron ellipsometry. The experimental dielectric function was simulated with the critical point parabolic band model. The parameters of the dispersive structures were derived by numerical fitting of the experimental data to the proposed model. New high energy optical transitions are resolved at 5.95, 7.8 and 8.82 eV and their lineshape and origin are discussed. The temperature dependence of the critical point energies and transition strengths was determined, and the excitonic effect is considered.

CC chemokine receptor 5 influences late-stage atherosclerosis

Members of the chemokine system, play a central role in inflammatory processes that underlie the pathogenesis of atherosclerosis and possibly, aortic valve sclerosis. Here we show that genetic inactivation of CC chemokine receptor 5 (CCR5) in the atherosclerosis-prone Apoe-/- mice (Apoe-/- Ccr5-/-) fed a normal chow or a high-fat diet (HFD) are protected against advanced atherosclerosis as well as age-associated aortic valve thickening (AAAVT)--a murine correlate of aortic valve sclerosis. Notably, human sclerotic valves contained CCR5+ cells. We confirm that Apoe-/- Ccr5-/- mice does not influence early-atherosclerotic stage. Adoptive transfer studies showed that the atheroprotective effect of CCR5 inactivation resided in the bone marrow compartment, but was not dependent on T-cells. The CCR5-null state was associated with phenotypes postulated to be atheroprotective such as reduced macrophage accumulation in the plaque, and lower circulating levels of IL-6 and MCP-5. The lack of CCR5 expression in Apoe-/- mice was also associated with higher numbers of endothelial progenitor cells (EPCs)--another postulated athero-protective factor. Compared with controls, carriers of a polymorphism in the Ccr5 gene that leads to the lack of CCR5 in the cell surface had an increased mean percentage of EPCs, but this difference did not reach statistical significance. Collectively, these findings underscore a critical role of CCR5 in age-associated cardiovascular diseases, and highlight that the effects of the chemokine system can be temporally constrained to distinct stages of these disease processes.

CC chemokine receptor (CCR)-2 prevents arthritis development following infection by Mycobacterium avium

The host factors that influence autoimmune arthritides such as rheumatoid arthritis have not been fully elucidated. We previously found that genetic inactivation of CC chemokine receptor 2 (CCR2) in the arthritis-prone DBA/1j mouse strain significantly increases the susceptibility of this strain to autoimmune arthritis induced by immunization with collagen type II (CII) and complete Freund's adjuvant (CFA). Here, we show that following intradermal infection with Mycobacterium avium, a similar arthritis phenotype was detected in Ccr2-null mice in the DBA/1j, but not in the BALB/c background. The failure to develop arthritis in Ccr2-null BALB/c mice occurred in the face of high bacterial burdens and low interferon gamma (IFNgamma) production. By contrast, Ccr2-null DBA/1j mice had low bacterial burdens, produced normal amounts of IFNgamma, and had high titers of autoantibodies against CII. Thus, the Ccr2-null state in an arthritic-prone genetic background leads to increased arthritis susceptibility following infectious (M. avium) and noninfectious (CII/CFA) challenges. Because CCR2 serves as a negative regulator of murine arthritis, caution might need to be exercised while testing CCR2 blockers in human arthritis or other diseases. These findings also indicate that Ccr2-null DBA/1j mice might serve as a valuable model system to uncover the immunological determinants of arthritis and to test novel antiarthritic agents.

Step-controlled strain relaxation in the vicinal surface epitaxy of nitrides

On-axis and vicinal GaN/AlN/6H-SiC structures grown under identical conditions have been studied by x-ray diffraction and transmission electron microscopy to demonstrate the distinctive features of vicinal surface epitaxy (VSE) of nitrides on SiC. In VSE, the epilayers are tilted from the substrate due to the out-of-plane lattice mismatch (Nagai tilts), and the in-plane mismatch strains are more relaxed. The majority of misfit dislocations (MDs) at the vicinal AlN/6H-SiC interface are found to be unpaired partial MDs that are geometrically necessary to correct the stacking sequences from 6H to 2H. This mechanism indicates that it is possible to develop "step-controlled-epitaxy" strategies to control strain relaxation by adjusting the substrate offcut angles.

Simulation of threading dislocation images in X-ray topographs of silicon carbide homo-epilayers

Three types of dislocation are seen in homo-epilayers of SiC grown on 4H-SiC wafers with an 8° surface offcut: axial screw dislocations, basal plane dislocations propagated into the epilayer at an 8° inclination and threading edge dislocations. These types may be imaged by monochromatic synchrotron X-ray topography in the grazing-incidence reflection geometry using the 11\overline 28 reflection. Equations needed to apply the ray-tracing method of computer simulating X-ray topographic defect images in this experimental geometry were derived and used to simulate images of all three. Simulations for axial screw dislocations appear as white circles surrounded by narrow dark rings, and those for basal plane dislocations as linear white streaks, both consistent with experimental topographs. Simulations of the threading edge dislocations showed 4 µm wide white ovals with narrow arcs of dark contrast at their ends, inclined relative to the g vector of the topograph according to the sign of their Burgers vector. These images resembled the experimental topographs inasmuch as was possible at the maximum resolution of X-ray topographs.

Periorbital swelling: the important distinction between allergy and infection

Orbital cellulitis and abscess formation are rare complications of sinusitis, however acute orbital inflammation is secondary to sinusitis in about 70% of cases. Delay in diagnosis must not occur to avoid serious complications such as blindness and life threatening intracranial sepsis. A case is reported in which despite late referral, emergency surgical intervention was sight saving.

Secretory proteins in the reproductive tract of the snapping turtle, Chelhydra serpentina

SDS-polyacrylamide gel electrophoresis was used to separate the secretory proteins produced by the epithelial and endometrial glands of the uterine tube and uterus in the snapping turtle Chelydra serpentina. The proteins were analyzed throughout the phases of the reproductive cycle from May to August, including preovulatory, ovulatory, postovulatory or luteal, and vitellogenic phases. The pattern of secretory proteins is quite uniform along the length of the uterine tube, and the same is true of the uterus, but the patterns for uterine tube and uterus are clearly different. We identify 13 major proteins in C. serpentina egg albumen. Bands co-migrating with 11 of these are found in the uterine tube, but at most 4 are found in the uterus, suggesting that the majority of the albumen proteins are most likely secreted in the uterine tube, not in the uterus. Although some of the egg albumen proteins are present in the uterine tube only at the time of ovulation, most of the bands corresponding to albumen proteins are present throughout the breeding season even though the snapping turtle is a monoclutch species. These results suggest that the glandular secretory phase in the uterine tube is active and quite homogeneous in function regardless of location or phase of the reproductive cycle.

The contrast of inclusions compared with that of micropipes in back-reflection synchrotron white-beam topographs of SiC

Images of inclusions in synchrotron white-beam back-reflection X-ray topographs appear as spots of light contrast surrounded by darker rings, resembling images of micropipes, which appear as distinct white circles surrounded by dark rings. Section topographs taken across the centers of micropipes gave vertically displaced two-tailed images, arising from the helical tilt of the reflecting planes about the micropipes' screw dislocation axes. Section topographs taken across the inclusions showed no vertical displacement, only dark bars bracketing a region of depleted contrast, arising from the convex bulge of the reflecting planes lying above the inclusion. The features of the inclusion images could be reproduced in computer simulations based on the elastic displacement function of a spherical inclusion in a semi-infinite solid, and compared with others based on the displacement function of a screw dislocation in an infinite solid.

Surface-relaxation contributions to axial screw dislocation contrast in synchrotron white-beam X-ray topographs of SiC

Micropipe images appeared in synchrotron white-beam X-ray topographs of thin basal-cut SiC wafers taken using prismatic reflections whereg · b= 0. They consisted of white ovals inclined along the direction of the topographs'gvector that were terminated with dark spikes at either end. The thin wafers tended to curl; the appearance of a defect's image varied depending on the sign of the curvature relative to the side serving as the diffracted beam's exit surface. The micropipe images were computer simulated using the ray-tracing method. The calculation assumed that they arose from the surface-relaxation strain component of a closed-core screw dislocation perpendicular to the surface of a thin foil. The qualitative features of the micropipe images were reproduced in their simulations, but the magnitude of the lattice misorientations predicted by the model was not large enough to account for the size of the experimentally observed dislocation images.

Synchrotron white-beam X-ray topography of ribonuclease S crystals

With careful experimental design, indexed synchrotron white-beam X-ray topographs of ribonuclease S crystals at ambient temperature could be recorded with a definition and contrast comparable to that of monochromatic beam topographs of other proteins reported in the literature. By excluding wavelengths longer than 1 A from the white beam with a filter, a radiation dose equivalent to that required to record about 18 topographs could be tolerated without appreciable radiation damage to the samples. Bragg angles of 0.5 degrees or less were required to select low-index harmonically pure reflections with high intensities and extinction lengths only several times the sample's thickness. The resulting X-ray topographs in some cases showed topographic detail and in others showed the even featureless background that has been considered characteristic of a protein crystal of low mosaicity. The ribonuclease S crystals were well ordered single crystals of a quality comparable to other protein crystals that have been studied by X-ray topography.

Popped eye (blunt trauma leading to penetrating eye injury and lens displacement in the pseudophakic eye)

Blunt trauma to the eye of patients with an artificial intraocular lens may cause globe rupture with all the accompanying sequelae. It must be recognised promptly and dealt with appropriately before urgent referral to ophthalmology.

From efficacy to effectiveness: managing organisational change to improve health services for young people with deliberate self harm behaviour

Repeat Deliberate Self Harm is a recognised risk factor for completed suicide and therefore reduction by effective health service response represents a valid contribution to suicide prevention. However, only a small fraction of people with deliberate self harm presentations to general health settings actually reach specialist mental health follow-up appointments. Therefore, even if responses at that point are known to be effective they do not make a significant contribution to reducing repeat self-harm overall. We describe health system organisational change strategies to improve health service engagement for the target group, and present data demonstrating the effectiveness of these strategies.

X-ray topographic dislocation contrast visible in reflections orthogonal to the Burgers vectors of axial screw dislocations in hexagonal silicon carbide

Contrast is associated with micropipes in X-ray topographs of SiC crystals obtained with prismatic reflections, representing an apparent violation of theg·b= 0 invisibility criterion. This is explained as a population of basal-plane dislocations with Burgers vectors of the setb= {\textstyle{1 \over 3}}〈11{\bar{2}}0〉 that occur in a high density within a few micrometers of the micropipes, below the resolution of X-ray topography. These basal-plane dislocations could be observed under an electron microscope. The presence of the surfaces of the micropipes influences the dislocation images in the topographs taken with prismatic reflections, often resulting in a band of light contrast along the axes of the micropipes.

Forbidden X-ray wavefields of three-beam Bragg reflections from thick crystals

A detailed analysis of a three-beam diffraction dispersion surface is performed to study the forbidden wavefields of thick-crystal Bragg reflections. From the asymptotic transition between two- and three-beam diffraction, it is found that the excitation state of each wavefield can be accurately determined with the two-beam criterion. Consequently, Bragg-case three-beam diffraction from thick crystals is either a four-mode diffraction process for the Bragg-Laue geometry or a two-mode process for the Bragg-Bragg geometry, and the amplitudes of the excited wavefields can be completely determined by the entrance boundary conditions. Based on this picture, the intrinsic mechanisms underlying three-beam Bragg reflections are clearly illustrated.

Systematic process and outcome evaluation of brief staff training in psychosocial interventions for severe mental illness

This study evaluated systematically the integrity and effectiveness of a topical staff training programme. The integrity of the training was evaluated in terms of its adherence to the trainer's protocol, using an observational instrument. To assess effectiveness, multiple measures of learner satisfaction, learning, generalisation and impact were administered longitudinally to N = 45 multi-disciplinary mental health professionals in the UK. The integrity evaluation indicated that the training had been delivered appropriately. Significant effects of the training were obtained on the learning assessments (knowledge gain and skill enhancement) and on the generalisation measure. No adverse effects were found, and learner satisfaction was very favourable. The findings indicate that a brief in-service training programme can be delivered consistently and can foster good practice amongst mental health staff, leading to benefits for their clients.

Superscrew dislocation contrast on synchrotron white-beam topographs: an accurate description of the direct dislocation image

A kinematic (geometrical) diffraction simulation model has been developed to provide understanding of direct dislocation images on synchrotron white-beam X-ray topographs, and has been successfully applied to illustrate the contrast formation mechanisms involved in images of micropipe-related superscrew dislocations in silicon carbide crystals. The coincidence of the simulations with the contrast features of the superscrew dislocation images, recorded using a series of synchrotron topography techniques, shows that this model is capable of revealing the detailed diffraction behavior of the highly distorted region around the dislocation core and determining the quantitative characteristics of the dislocations. The simulation technique is thus demonstrated to be a simple but efficient method for interpretation of synchrotron topographs, and may be applied to explain the topographic contrast characters of general crystal defects.

Craniofacial trauma presenting at an adult accident and emergency department with an emphasis on soft tissue injuries

We have retrospectively compiled data on 1000 consecutive adult patients presenting at an accident and emergency department (AED) with a total of 1048 soft tissue injuries and 151 fractures to the craniofacial region, with an emphasis on soft tissue injuries. Facial injuries were common in the AED, forming 7% of all attenders. The main cause of facial fractures was assaults (56%), whereas the largest proportion of soft tissue injuries was caused by falls/ accidents (44%). There was a left sided dominance in soft tissue injuries arising from assaults. However, when subdivided into type of soft tissue injuries, the left sided dominance was significant in contusions only, with virtually equal side distribution in open wounds. Almost half of the 458 open wounds which required treatment were in the upper third of the face. Most lacerations in the upper face can be managed by steristrips or glue but most lacerations in the lower third required suturing. 90% of these injuries were treated by AED personnel. Tertiary referrals were made in only 10% of these cases.

Fish oil supplementation does not impair the gut immune response to Trichinella spiralis infection in rats

BACKGROUND

Fish oil has been recommended as a source of omega-3 fatty acids for preterm infants and for therapy of some inflammatory diseases.

METHODS

Because fish oil supplementation could downregulate the host's immune response, we studied the gut inflammatory response to an enteric infection in 72 rats assigned to three dietary groups with differing fatty acid profile: 1) fish oil, rich in eicosapentaenoic and docosahexaenoic acid; 2) olive oil, containing 71% monounsaturated fat; and 3) rat chow, containing 57% saturated fat. One half (n = 36) of the rats were infected with Trichinella spiralis larvae; the other half served as controls. The inflammatory response to initial infection (study 1), and type I hypersensitivity response to a subsequent parasite-derived antigenic challenge (study 2) were assessed. Jejunal inflammatory cell infiltrate, mean villus height, disaccharidase levels, changes in short-circuit current in response to glucose absorption, and chloride secretagogues (study 1) were measured 9 days after infection. Short-circuit current changes induced by chloride secretion were measured when the proximal jejunum was challenged with T. spiralis-derived antigen 40 days after infection (study 2).

RESULTS

In study 1, jejunal tissue from infected animals had more eosinophilic infiltrate, lower disaccharidase levels, and less glucose absorptive and chloride secretory capacity than tissue from noninfected animals. In study 2, the jejunum of infected animals showed an antigen-induced chloride secretory response, whereas no response was obtained from jejunal tissue from noninfected animals. Type of diet did not affect the response in either study.

CONCLUSION

Under the conditions of this experiment, fish oil supplementation did not interfere with the local intestinal inflammatory response after T. spiralis infection.

Harmonic composition of synchrotron white-beam X-ray topographic back-reflection images of basal-cut silicon carbide single-crystal wafers

Superscrew dislocations are visible in back-reflection synchrotron white-beam X-ray topographs of basal-cut SiC wafers in striking contrast as black rings surrounding white circles, even though such topographs suffer from extensive harmonic contamination. The contributions to the synchrotron white-beam topograph of each member of its series of harmonic reflections, {\bf g}=(0006n), where n=3 to 16, were calculated. Through intensity considerations and comparison with a {\bf g}=00018 topograph taken with Cu Kα1radiation, the {\bf g}=00024 harmonic was determined to be the most important contributor. The contrast of features lying deep beneath the crystal's surface was attributed to higher harmonics with larger penetration depths.

Coroners' records of rural and non-rural cases of youth suicide in New South Wales

OBJECTIVE

The aim of this study is to compare the frequency of certain putative risk factors for youth suicide in New South Wales (especially use of alcohol, social class, unemployment, and internal migration) in metropolitan and rural settings.

METHOD

A review of 137 files for 10-19-year-old subjects judged by the Coroner to have committed suicide in 1988-1990 was carried out.

RESULTS

One hundred and fifteen males and 21 females were identified (one subjects sex was unavailable). The male-female ratio was higher in rural (13.0) areas than non-rural (4.9 chi 2 = 12.14, p < 0.01). Of 27 subjects migrating within Australia, most migrated in a rural direction, and most to rural shires. Unemployment was somewhat more common among rural (38.5%) than non-rural (28.9%) subjects (chi 2 = 0.75, p = 0.39). Eleven of 50 non-rural parents of the deceased, but none of the 11 rural parents, were ranked as being in social classes 2 or 3. Alcohol consumption appeared more common in rural shires (44%) than metropolitan areas (32.9%), but this was not statistically significant. Medical services were less utilised prior to death in rural (15%) than non-rural (25%) areas (chi 2 = 1.69, p = 0.19), and a psychiatric diagnosis was recorded more commonly in non-rural areas.

CONCLUSIONS

Incomplete coronial file data and relatively small numbers limit this study's conclusions. Male suicides, principally by firearms, predominated in rural areas. Youth firearm access remains highly relevant to rural communities. Possible trends among rural subjects toward rural migration, higher unemployment, lower social class and lower medical attendance may point to resource deprivation among this group; these matters require further investigation.

Open reduction and bone plate stabilization, compared with closed reduction and external fixation, for treatment of comminuted tibial fractures: 47 cases (1980-1995) in dogs

OBJECTIVE

To compare open reduction and bone plate fixation with closed reduction and external skeletal fixation as treatment for severely comminuted fractures of the tibia. Limb alignment, fracture reduction, operating time, hospitalization time, postoperative care, time to unrestricted activity, bone healing, complications, and number of surgical procedures were considered.

DESIGN

Retrospective case series.

ANIMALS

47 dogs with severely comminuted fractures of the tibia treated with open reduction and bone plate application (22 dogs) or closed reduction and external fixation (25 dogs).

PROCEDURE

Medical records of all dogs included in this study were reviewed. Postoperative and follow-up radiographs were evaluated by 2 independent observers.

RESULTS

Differences were not found in hospitalization time, time to unrestricted activity, or time to earliest radiographic evidence of bone healing between dogs with fractures treated with a bone plate and dogs with fractures treated with an external fixator. Fractures treated with an external fixator had more caudal malalignment, and fractures treated with a bone plate had more valgus malalignment. Malalignments were determined not to be related to clinical problems. Dogs with fractures treated with an external fixator had shorter surgery times and more recheck examinations. Dogs with fractures treated with a bone plate had more complications.

CLINICAL IMPLICATIONS

Open reduction with bone plate fixation and closed reduction with external fixation were both effective for treatment of comminuted tibial fractures. External fixation was associated with shorter surgery time, but dogs required more extensive postoperative care. Bone plate fixation was associated with more complications.

Assessment of the value of technician reporting of electrocardiographs in an accident and emergency department

OBJECTIVE

To assess the value of a cardiac technicians' report on electrocardiographs (ECGs) in reducing serious errors of interpretation by senior house officers.

METHODS

A parallel study of interpretation of ECGs by senior house officers from 238 cases seen in an accident and emergency (A&E) department in a teaching hospital. 129 ECGs were reported by a cardiac technician at the time of recording and before the senior house officer wrote a report, and 109 were reported only by the senior house officers. Misinterpretations by doctors and technicians were graded by a consultant cardiologist on a four point scale and compared in the two groups. Serious errors (grade 4) were defined as those which potentially affected immediate management.

RESULTS

The number of grade 4 errors of interpretation of ECGs by A&E senior house officers was reduced by 59% when there was a prior technical report (mean (SD), 18(17)% v 6 (7%); Fisher's exact test P < 0.05).

CONCLUSIONS

When cardiac technicians provide a report on an ECG at the time of its recording, serious errors of interpretation by senior house officers are reduced.

Suicide among young rural Australians 1964-1993: a comparison with metropolitan trends

The study tested hypotheses that from 1964 to 1993: (1) suicide rates among Australian 15- to 24-year-old males rose more sharply in rural than metropolitan areas; (2) firearm suicide rates among 15- to 24-year-old males, declining throughout Australia recently, rose continuously in rural areas; (3) suicide rates among 15- to 24-year-old females did not change significantly in either metropolitan or rural areas. Suicides of those aged 10-24 years recorded by the Australian Bureau of Statistics (ABS) were classified according to the subject's residential grouping. Rates were calculated using ABS population data corresponding to these groupings. Results were analysed using log-linear analysis and chi-square statistics. The results supported the first two hypotheses, but not the third. Suicide rates for 15- to 24-year-old males rose by a factor of 2.2 in metropolitan areas, by 4-fold in towns with populations between 4,000 and 25,000, and by 12-fold in towns with populations less than 4,000. Male firearm suicide rates continued to rise in rural areas, and the greatest proportion of deaths in those locations were by firearms, though male hanging rates increased most in recent years in all locations. Female youth suicide rates did not change overall, but in towns with populations less than 4,000, they increased 4.5-fold. Possible explanations for this epidemic, which are mostly speculative and require confirmation, are discussed.

Jumping the gun: firearms and the mental health of Australians

OBJECTIVES

The aims of this study were to (i) survey mental health-related correlates of firearms ownership and availability in Australia, and (ii) assess possible causal relationships between civilian gun deaths, gun availability and mental disorders.

METHOD

Available data regarding firearms ownership, injuries and deaths were reviewed as well as studies of (i) gun ownership, suicide and homicide, and (ii) gun control laws and suicide.

RESULTS

Findings indicated that 85% of firearm deaths are triggered by distress, as opposed to crime. Most firearm homicides are intrafamilial or involve familiar persons. Firearm suicide rates, although tapering off in recent years, continue to rise among certain groups. It was also found that: (1) Beyond reasonable doubt, a causal relationship exists between gun ownership and firearm suicides and homicides. The role of method substitution is controversial, but is probably less important among the young. (2) Outside the United States, legislation may be useful in reducing firearm and possibly overall suicide rates. (3) If firearm owners are representative of the community, then 15-20% suffer from a psychiatric disorder at any time. While a modest increase in risk of firearms misuse exists for this group, especially those with a history of substance abuse or violence, concern also arises regarding those with mental disorders who access firearms because owners have not secured them. No uniform definition or way of verifying self-reports exists for gun licence applicants regarding these issues.

CONCLUSIONS

Further regulation of firearm safety and availability is warranted. Public health measures include improved surveillance regarding firearm events, advocacy for appropriate firearm legislation, and better education and communication about firearms.

Bacterial resistance mechanisms to beta-lactam antibiotics: assessment of management strategies

Several mechanisms render antimicrobials inactive; one of these, beta-lactamase hydrolysis of beta-lactam antimicrobials, is a common and serious problem resulting in loss of antimicrobial activity. Resistance in gram-negative organisms may be caused by chromosomally or plasmid-mediated beta-lactamases. Chromosomally mediated resistance may result from exposure to inducer compounds (induction) or by selection of stably derepressed mutants. Plasmids are extrachromosomal elements of DNA that can transfer resistance between bacteria. Common plasmid-encoded beta-lactamases are the TEM- and SHV-type enzymes, which include the newer extended-spectrum beta-lactamases. Infections caused by resistant bacteria frequently result in longer hospital stays, higher mortality, and increased cost of treatment. When bacteria develop resistance during antimicrobial therapy, therapeutic failure ensues in approximately 50% of patients. Clinical studies demonstrate that resistance mediated by beta-lactamases is a critical issue. Strategies for overcoming it include use of beta-lactam-beta-lactamase inhibitor combinations, development of new antimicrobial compounds, and use of regimens that optimize in vivo exposure to drug.

Images of psychiatry in recent Australian and New Zealand fiction

Psychiatry is variously portrayed in Australian and New Zealand fiction. This paper describes mental health professionals, settings, conditions, treatments, and social themes essayed in 128 works by 103 authors, published between 1957 and 1992. The predominant images are negative or markedly ambivalent: possible reasons for this are discussed. The perception of psychiatry by the culture in which it is formed and located, as mediated by its creative artists, has important implications for psychiatrists' understanding and explication of their social role, and has an impact on patients' expectations and experiences of psychiatry.

Dietary cholesterol supplementation improves growth and behavioral response of pigs selected for genetically high and low serum cholesterol

We hypothesized that, in pigs selected for low (L) or high (H) serum cholesterol for four generations, neonatal endogenous cholesterol synthesis would be sufficient to meet requirements for brain and body growth. In Experiment 1, eight 16-wk-old L pigs received a diet with or without 200 mg cholesterol/100 g diet for 35 d. Supplemented pigs grew approximately 25% faster and had a significantly greater concentration of free cholesterol in the cerebrum. In Experiment 2, 16 H and 16 L newborn pigs were fed a milk replacer with or without 200 mg cholesterol/100 g diet for 28 d. Pigs fed cholesterol had greater average daily gain (P < or = 0.09), significantly reduced liver 3-hydroxy-3-methylglutaryl-coenzyme A reductase activity, and significantly increased cerebral cholesterol content than pigs not fed cholesterol. One of three indices of exploratory behavior was significantly greater in the L pigs that received cholesterol compared with L pigs that did not receive cholesterol. These data suggest that these neonatal pigs are unable to produce sufficient cholesterol to meet requirements for normal growth and brain development and are dependent on dietary cholesterol in milk.

Mood disorders among mothers of infants admitted to a mothercraft hospital

The mothers (n = 100) of consecutive infants admitted to a mothercraft residential facility were asked to complete the Edinburgh Postnatal Depression Scale (EPDS). Only one of the women had been identified prior to the infant's admission as having postnatal depression, but 39% scored above the cut-off point for likely major depressive disorder. No specific infant problem correlated significantly with a higher depression score. The extent of serious mood disorders in the post-partum population has remained generally unacknowledged despite an upsurge of recent research activity in the field. Nevertheless, this problem has considerable public health significance, impinging as it does on the health of all members of the family. Possible screening and intervention strategies are discussed.

Psychosocial interventions for very low birthweight infants: their scope and efficacy

With the burgeoning of infant psychiatry, and the increasing survival and development of cohorts of very low birthweight (VLBW) infants, psychiatrists are becoming increasingly involved with other professionals in designing and implementing early intervention programs. Psychosocial interventions for VLBW infants generally report positive results regardless of the orientation of the practitioners, or the stated goal of the intervention: however, they have often taken place independently of longitudinal research, and sometimes without grounding in theories of infant and family development. This paper first reviews the current state of research and findings related to infant-focussed, parent-directed, and interactional programs. Second, it addresses a number of basic questions to be considered by psychiatrists involved in consulting to neonatal intensive care units, who have to appraise, design or implement intervention programs with this group. Throughout this discussion, it is proposed that the notion of infants at developmental risk needs to be supplemented by that of caregivers at risk, and that the professional boundaries which these distinctions represent need to be overcome.

The relationship between psychosocial factors and developmental outcome for very low and extremely low birthweight infants: a review

Over the last quarter century, the improved survival rate of very low birthweight infants has sharpened questions about their residual disabilities. Longitudinal studies have devoted attention to the cognitive and neurodevelopmental outcome of these infants, but much less is known about their long-term social and emotional development. Psychiatrists consulting to neonatal intensive care units and assessing these infants in their families, will be assisted by a better understanding of the developmental and psychological outcomes of such infants. This paper reviews the state of knowledge in both of these areas. It argues the paramount importance of psychosocial factors to the infants' developmental outcome, and the importance of longitudinal research in further clarifying the predictive value of these factors. In a subsequent paper, we consider the efficacy of interventions with this group.

The heterochronic Teopod1 and Teopod2 mutations of maize are expressed non-cell-autonomously

Teopod1 and Teopod2 are dominant, unlinked mutations in maize that cause dramatic morphological abnormalities, including inappropriate expression of juvenile traits in adult vegetative phytomers and the transformation of reproductive structures into vegetative ones. These phenotypes are consistent with the constitutive expression of a juvenile phase of development throughout shoot growth. To investigate the basis of the Tp1 and Tp2 phenotypes we have analyzed their cell-autonomy in mosaic Teopod:wild-type plants. Mosaic plants were generated by three different mechanisms. Tp1 has previously been shown to be non-cell-autonomous; to verify and extend these results, large wild-type sectors were generated on Tp1 plants by the spontaneous loss of a B-A translocation chromosome containing the Tp1 gene. Analysis of Tp2 cell-autonomy was complicated by a lack of useful markers on chromosome 10L proximal to Tp2. To circumvent this problem two strategies were used. A reciprocal translocation was used to link Tp2 the wild-type allele of lw2. Sectors were induced in plants of this type by irradiation of imbibed seeds. Also, a chromosome-breaking Ds element located proximal to Tp2 was used to generate somatic sectors that uncovered w2, an albino mutation distal to Tp2. Our results demonstrate conclusively that both Tp1 and Tp2 are non-cell-autonomous. The general use of these techniques for clonal analysis in plants and the potential role of a diffusible factor in regulating the juvenile phase of development in maize are discussed.

Youth suicide in New South Wales: urban-rural trends

OBJECTIVE

The study tested the hypotheses that (i) the rate of suicide by firearms among youth (aged 10-19 years) is increasing at a greater rate than rates of suicide by other methods; (ii) the rate of youth suicide in rural New South Wales is significantly higher than those in urban areas; and (iii) the increase in youth suicide by means of firearms is occurring at a greater rate in rural males aged 15-19 years than in other groups.

DESIGN

Data were obtained from the NSW Office of the Australian Bureau of Statistics concerning 735 youth suicides in NSW between 1964 and 1988. These were reviewed for information concerning residential area and method of death. Five five-year periods were used, and rates were calculated with population figures obtained in the census years for the same age and sex group.

RESULTS

From 1964 to 1988, suicide by firearms has risen most substantially, from 3.4 to 5.6 per 100,000 per year in 15-19-year-old males. There has also been a substantial increase in 15-19-year-old male suicides by hanging (0.7 to 3.4 per 100,000 per year). Poisoning suicides have declined among females and males in the past 15 years. Suicide rates in Sydney, Newcastle and Wollongong have remained stable. In rural cities, they have increased from 1.5 to 4.7 per 100,000 per year (F = 4.9, P less than 0.02) while in rural municipalities and shires they have increased from 1.3 to 6.4 (F = 14.6, P less than 0.0001). The suicide rate of 15-19-year-old males has shown a modest increase in Sydney and no change in Newcastle or Wollongong, but the rate for 15-19-year-old males in rural cities has more than doubled, from 5.1 to 12.5 (F = 7.7, P less than 0.003), while in rural municipalities and shires, the rate has increased more than fivefold, from 3.9 to 20.7 (F = 9.3, P less than 0.001). There has been no significant change in the suicide rates of 15-19-year-old females, or in 10-14-year-olds. The rate of suicide by firearms among 15-19-year-old males has not risen significantly in rural cities, but in rural municipalities and shires the rates have risen fivefold from 2.8 to 14.8 (F = 5.6, P less than 0.01).

CONCLUSIONS

Each hypothesis was confirmed. An increase of this magnitude is not an artefact of coroners' verdicts. The findings are believed to be due to ready access to firearms, the use of alcohol and drugs (particularly in firearms suicides) and increasing socioeconomic, health, and identity problems for rural youth, especially males.