Biomedical subjects

J Dunn

Publications and source records attributed to J Dunn.

At least 19 recordsLinked to original sources

PubMed2007

Crack cocaine: a five-year follow-up study of treated patients.

OBJECTIVES: To follow-up a group of 131 crack cocaine users and examine drug use, treatment experience, employment status, involvement in crime and mortality at 2 and 5 years. METHODS: Consecutive crack-dependent patients who were admitted to a detoxification unit in São Paulo between 1992 and 1994 were re-interviewed on two occasions: 1995-1996 and 1998-1999. RESULTS: 5 years after treatment information was obtained on 124 (95%) of the original cohort. 39.7% (n = 52) of the patients reported having been abstinent from cocaine for at least the last year, and 21.4% (n = 28) had used the drug. Of those subjects not using cocaine at 2 years, 19 (62%) were still abstinent at 5 years. Twenty-three (17.6%) patients had died by the 5-year follow-up with homicide, due to firearms or other weapons, being the commonest cause (n = 13). The annual adjusted mortality rate for the sample was 24.92 deaths/1,000 individuals, the excess mortality rate was of 21.64 deaths/1,000 individuals, and the standardized mortality ratio was 7.60. A history of injecting drug use, unemployment at the time of the index admission and administrative discharge at the index admission were factors that contributed to the risk of dying over the next 5 years. CONCLUSIONS: There was a progressive movement towards abstinence over the follow-up period, and there was evidence that once abstinence had been achieved it was maintained. On the other hand, the mortality rate was extremely high and was higher among those who were still using crack at 2 years.

Adolescent↗

PubMed2006

Continuous high-repetition-rate operation of collisional soft-x-ray lasers with solid targets.

We have generated a laser average output power of 2 microW at a wavelength of 13.9 nm by operating a tabletop laser-pumped Ni-like Ag laser at a 5 Hz repetition rate, using a solid helicoidal target that is continuously rotated and advanced to renew the target surface between shots. More than 2 x 10(4) soft-x-ray laser shots were obtained by using a single target. Similar results were obtained at 13.2 nm in Ni-like Cd with a Cd-coated target. This scheme will allow uninterrupted operation of laser-pumped tabletop collisional soft-x-ray lasers at a repetition rate of 10 Hz for a period of hours, enabling the generation of continuous high average soft-x-ray powers for applications.

Journal Article↗

PubMed2006

A genome-wide linkage scan for genes controlling variation in urinary albumin excretion in type II diabetes.

The main hallmark of diabetic nephropathy is elevation in urinary albumin excretion. We performed a genome-wide linkage scan in 63 extended families with multiple members with type II diabetes. Urinary albumin excretion, measured as the albumin-to-creatinine ratio (ACR), was determined in 426 diabetic and 431 nondiabetic relatives who were genotyped for 383 markers. The data were analyzed using variance components linkage analysis. Heritability (h2) of ACR was significant in diabetic (h2=0.23, P=0.0007), and nondiabetic (h2=0.39, P=0.0001) relatives. There was no significant difference in genetic variance of ACR between diabetic and nondiabetic relatives (P=0.16), and the genetic correlation (rG=0.64) for ACR between these two groups was not different from 1 (P=0.12). These results suggested that similar genes contribute to variation in ACR in diabetic and nondiabetic relatives. This hypothesis was supported further by the linkage results. Support for linkage to ACR was suggestive in diabetic relatives and became significant in all relatives for chromosome 22q (logarithm of odds, LOD=3.7) and chromosome 7q (LOD=3.1). When analyses were restricted to 59 Caucasian families, support for linkage in all relatives increased and became significant for 5q (LOD=3.4). In conclusion, genes on chromosomes 22q, 5q and 7q may contribute to variation in urinary albumin excretion in diabetic and nondiabetic individuals.

Adult↗

PubMed2005

Plasma conditions for improved energy coupling into the gain region of the Ni-like Pd transient collisional x-ray laser.

We have directly probed the conditions in which the Ni-like Pd transient collisional x-ray laser is generated and propagates by measuring the near-field image and by utilizing picosecond resolution soft x-ray laser interferometry of the preformed Pd plasma gain medium. The electron density and gain region of the plasma have been determined experimentally and are found to be in good agreement with simulations. We observe a strong dependence of the laser pump-gain medium coupling on the laser pump parameters. The most efficient coupling occurs with the formation of lower density gradients in the preformed plasma and when the duration of the main heating pulse is comparable to the gain lifetime (approximately 10 ps for mid- Z Ni-like schemes). This increases the output intensity by more than an order of magnitude relative to the commonly utilized case where the same pumping energy is delivered within a shorter heating pulse duration (<3 ps) . In contrast, the higher intensity heating pulses are observed to be absorbed at higher electron densities and in regions where steep density gradients limit the effective length of the gain medium.

Journal Article↗

PubMed2005

High-repetition-rate grazing-incidence pumped x-ray laser operating at 18.9 nm.

We have demonstrated a 10 Hz Ni-like Mo x-ray laser operating at 18.9 nm with 150 mJ total pump energy by employing a novel pumping scheme. The grazing-incidence scheme is described, where a picosecond pulse is incident at a grazing angle to a Mo plasma column produced by a slab target irradiated by a 200 ps laser pulse. This scheme uses refraction of the short pulse at a predetermined electron density to increase absorption to pump a specific gain region. The higher coupling efficiency inherent to this scheme allows a reduction in the pump energy where 70 mJ long pulse energy and 80 mJ short pulse energy are sufficient to produce lasing at a 10 Hz repetition rate. Under these conditions and by optimizing the delay between the pulses, we achieve strong amplification and close to saturation for 4 mm long targets.

Journal Article↗

PubMed2005

Observation of a multiply ionized plasma with index of refraction greater than one.

We present clear experimental evidence showing that the contribution of bound electrons can dominate the index of refraction of laser-created plasmas at soft x-ray wavelengths. We report anomalous fringe shifts in soft x-ray laser interferograms of Al laser-created plasmas. The comparison of measured and simulated interferograms shows that this results from the dominant contribution of low charge ions to the index of refraction. This usually neglected bound electron contribution can affect the propagation of soft x-ray radiation in plasmas and the interferometric diagnostics of plasmas for many elements.

Journal Article↗

PubMed2005

Motivation for change in alcohol dependent outpatients from Brazil.

The general aim of this study was to investigate the reliability and factor structure of the stages of change readiness and treatment eagerness scale (SOCRATES) in 326 outpatients with alcohol dependence. The questionnaire was translated and cross-culturally adapted into Portuguese and back-translated to English. The confirmatory factor analysis showed that two correlated factors provided the best fit for the data.

Adult↗

PubMed2003

Scoreboard advertising at sporting events as a health promotion medium.

This report describes spectator recall of SunSmart skin cancer prevention advertising displayed on the Brisbane Cricket Ground scoreboard at intermittent periods throughout the 1999/2000 cricket season and the sun-protective behaviors of these spectators. Two hundred and thirty-one spectators were asked a series of five questions about their recall of SunSmart advertising and their present sunscreen usage. Respondents' sun-protective behavior observed at the time of questioning was also recorded. The SunSmart advertising was seen by 15.6% of respondents. Recall of the SunSmart advertising was higher amongst spectators observed to have high levels of sun protection than amongst spectators with low levels of sun protection. Females were more likely than males to recall the SunSmart advertising. The efficacy of health-promoting advertising in the sports setting has yet to be established and therefore results cannot be compared against accepted benchmarks. This study contributes baseline data that will enable such comparisons to be made. The increase in recent years of health-promoting advertising at sports events, often as part of a comprehensive sponsorship program, necessitates the need for further research in this area.

Advertising↗

PubMed2002

Picosecond x-ray laser interferometry of dense plasmas.

We present the first results from picosecond interferometry of dense laser-produced plasmas using a soft x-ray laser. The picosecond duration and short wavelength of the 14.7 nm Ni-like Pd laser mitigates effects associated with motion blurring and refraction through millimeter-scale plasmas. This enables direct measurement of the electron-density profile to within 10 microm of the target surface. A series of high-quality two-dimensional (2D) density measurements provide unambiguous characterization of the time evolution in a fast-evolving plasma suitable for validation of existing 1D and 2D hydrodynamic codes.

Journal Article↗

PubMed2002

Sterilization of plastic containers using electron beam irradiation directed through the opening.

AIMS: Studies were performed to demonstrate the efficacy of a novel electron beam irradiation system for the on-line sterilization of polymeric containers using energetic electrons directed through the container opening. METHODS AND RESULTS: The distribution of dosage delivered during conveyance beneath the electron beam treatment system was determined for two sizes (8 or 16 ounces) of high-density polyethylene (HDPE) blow-moulded bottles. The biological effects of treatment were then determined using Bacillus pumilus ATCC 27142 spores inoculated as 10 microl droplets dried (i) onto the surface of flat coupons of the high-density polyethylene bottle material, and (ii) onto the region of lowest delivered dose (the bottom side wall) within each bottle. The inactivation obtained was determined by examining the level of survival after swab recovery of the inoculated spores, with reference to the level recovered from untreated control samples. CONCLUSIONS: The inactivation of B. pumilus spores during treatment was reproducible and proportional to the applied dose. In each instance, the logarithm of the surviving fraction of spores was well fitted by linear regression models and in good general agreement with values reported for inactivation of the same organism using gamma irradiation. SIGNIFICANCE AND IMPACT OF THE STUDY: The results of this work demonstrate the potential of a new physical method capable of high throughput for in-line sterilization of polymeric containers. The ability of the process to eliminate the washing step involved with traditional chemical sterilants, such as hydrogen peroxide, greatly reduces the size and environmental impact of these systems.

Bacillus↗

PubMed2001

Does multisite sampling improve patient heterogeneity in drug misuse research?

The aim of this study was to investigate whether multisite sampling increased heterogeneity among a sample of cocaine users from São Paulo, Brazil. Six hundred and fourteen cocaine users were interviewed at 23 fixed sites plus an out-of-treatment sample. The sites were then regrouped into six main types: university outpatient clinics, public outpatient clinics, public inpatient units, private inpatient units, HIV services and non-treatment. Marked differences were found between users recruited at these sites, especially in relation to age, gender, employment status, criminal history, history of prostitution, previous drug misuse treatment, duration of cocaine use and lifetime use of intravenous cocaine. These results suggest that multisite sampling is a valid method for increasing patient heterogeneity, but whether it improves representativeness and thus the generalisability of drug misuse research is debatable.

Adult↗

PubMed2001

The effects of slice-selective excitation/refocusing in localized spectral editing with gradient-selected double-quantum coherence transfer.

Spectral editing using gradient-selected double-quantum filtering (DQF) with PRESS localization has been used for selective observation of metabolites in vivo. In previous studies using localized DQF sequences, it is generally assumed that the slice-selective pulses used in the sequence have no roles in coherence transfer, and do not interfere with DQF. To validate this assumption, the effects of slice-selective excitation/refocusing on DQF were investigated in DQF lactate editing sequences combined with PRESS localization. Contrary to the previous assumption, the results show that, due to chemical shift displacement artifact and J coupling, slice selection in DQF does interfere with coherence transfer, affecting both the accuracy of spatial localization and the detection sensitivity adversely. In the case of lactate editing, the effects of this interference can be accounted for simply by adjusting the strength of the slice-selection gradients and by using narrowband slice-selective refocusing pulses.

Calibration↗

PubMed2001

Acting nasty in the face of failure? Longitudinal observations of "hard-to-manage" children playing a rigged competitive game with a friend.

Peer problems are almost universal among children with disruptive behavior disorders, and have been linked to social information processing deficits that lead to heightened threat responses. This 2-year longitudinal study uses direct observations to examine the real-life significance of this finding. Forty "hard-to-manage" children and 40 typically developing control children were filmed at ages 5 and 7 playing a rigged competitive game in which they experienced a clear threat of losing. Group differences in negative behavior (hard-to-manage > controls) were stable over time and independent of verbal ability. Predictors of individual differences in negative behavior were also examined. Previous studies with this sample have shown that at 4 years of age, the hard-to-manage children displayed elevated frequencies of violent pretend play, coupled with poor performance on tests of executive function and theory of mind. In this study, 4-year-olds whose pretend play indicated a preoccupation with violence were more likely to respond negatively to the threat of losing a competitive game at age 5 and at age 7. Four-year-olds who performed poorly on tests of theory of mind and executive function showed higher rates of negative behavior at age 5 but not age 7. These findings highlight just a few of the multiple paths leading to peer problems among children with disruptive behavior problems.

Affect↗

PubMed2001

Men's attitudes toward prostate cancer and seeking prostate-specific antigen testing.

BACKGROUND: Although the Australian Cancer Society recommends against performing PSA tests to screen for prostate cancer, many Australian men currently undergo such screening. This study investigated attitudinal variables that may predict prostate cancer screening behaviors in this context. METHODS: A questionnaire was administered by mail in a two-phase procedure, first to a sample of 1,461 men (46% response), then to 919 men from the initial sample. Prostate cancer screening behaviors of men > 40 years old were examined. The questionnaire assessed worry about prostate cancer, perceived vulnerability to prostate cancer, belief in the efficacy of PSA testing for detection, having received a PSA test for detection, and the presence of urologic symptoms at the time of testing. RESULTS: Men who had had PSA testing with urologic symptoms at the time of the test were more worried about prostate cancer and perceived themselves as more vulnerable to prostate cancer compared with both asymptomatic tested and untested men. Men who had undergone PSA testing believed the test to be more effective in the detection of prostate cancer than did men who had not. CONCLUSIONS: Urologic symptoms act as a risk cue for men to prostate cancer. Asymptomatic men should be considered separately from symptomatic men in the investigation of psychological variables predictive of seeking screening for prostate cancer. These findings are discussed in terms of both the focus and design of interventions to alter prostate cancer screening behavior and their implications for the clinical management of men with urologic symptoms.

Adult↗

PubMed2001

Mental health and foster carer training.

AIMS: To evaluate the impact of training foster carers on children's emotional and behavioural functioning. METHODS: In a randomised controlled trial in 17 Scottish local council areas, with immediate and nine month follow up, 182 children and their foster families were randomly allocated to either standard services alone or standard services plus extra training for foster carers on communication and attachment. Main outcome measures were child psychopathology, attachment disorder, self esteem, and cost of foster care. RESULTS: Over 60% of children had measurable psychopathology at baseline. The training was perceived as beneficial by participants. Scores for parent reported psychopathology and attachment disorders decreased by around 5%, self esteem increased by 2%, and costs by 22% in the intervention group. Results were non-significant. CONCLUSIONS: Despite being well received by foster carers, the training was not sufficient to make a useful impact on the high level of psychopathology. This group may warrant more intensive interventions.

Caregivers↗

PubMed2001

Overexpression of Na+/Ca2+ exchanger alters contractility and SR Ca2+ content in adult rat myocytes.

The functional consequences of overexpression of rat heart Na+/Ca2+ exchanger (NCX1) were investigated in adult rat myocytes in primary culture. When maintained under continued electrical field stimulation conditions, cultured adult rat myocytes retained normal contractile function compared with freshly isolated myocytes for at least 48 h. Infection of myocytes by adenovirus expressing green fluorescent protein (GFP) resulted in >95% infection as ascertained by GFP fluorescence, but contraction amplitude at 6-, 24-, and 48-h postinfection was not affected. When they were examined 48 h after infection, myocytes infected by adenovirus expressing both GFP and NCX1 had similar cell sizes but exhibited significantly altered contraction amplitudes and intracellular Ca2+ concentration ([Ca2+]i) transients, and lower resting and diastolic [Ca2+]i when compared with myocytes infected by the adenovirus expressing GFP alone. The effects of NCX1 overexpression on sarcoplasmic reticulum (SR) Ca2+ content depended on extracellular Ca2+ concentration ([Ca2+]o), with a decrease at low [Ca2+]o and an increase at high [Ca2+]o. The half-times for [Ca2+]i transient decline were similar, suggesting little to no changes in SR Ca2+-ATPase activity. Western blots demonstrated a significant (P < or = 0.02) threefold increase in NCX1 but no changes in SR Ca2+-ATPase and calsequestrin abundance in myocytes 48 h after infection by adenovirus expressing both GFP and NCX1 compared with those infected by adenovirus expressing GFP alone. We conclude that overexpression of NCX1 in adult rat myocytes incubated at high [Ca2+]o resulted in enhanced Ca2+ influx via reverse NCX1 function, as evidenced by greater SR Ca2+ content, larger twitch, and [Ca2+]i transient amplitudes. Forward NCX1 function was also increased, as indicated by lower resting and diastolic [Ca2+]i.

Adenoviridae↗

PubMed2001

Why are children in the same family so different? Nonshared environment a decade later.

OBJECTIVE: To review recent developments in the study of nonshared environment; that is, the environmental influences that make children growing up in the same family different, rather than similar. METHOD: We review several recent influential books and papers on the subject of nonshared environment from the decade following the 1987 paper that highlighted its importance in psychological development. RESULTS: Modest progress has been made toward identifying the specific aspects of the environment responsible for nonshared environment. Although parents treat their multiple children differently, such differential treatment accounts for only a small amount of nonshared environmental influence, once genetic factors are controlled. It has been suggested that some degree of nonshared environment may be due to the fact that siblings react differently to ostensibly shared environmental influences. Peer influence and other experiences outside the family may be more important sources of systematic nonshared environment. CONCLUSIONS: Despite the difficulties encountered in identifying specific sources of nonshared environment, the fact remains that most environmental variance affecting the development of psychological dimensions and psychiatric disorders is not shared by children growing up in the same family. More research and theory are needed to explain why such siblings are so different. Chance, in the sense of idiosyncratic experiences, also needs to be considered.

Adoption↗

PubMed2001

Family settings and children's adjustment: differential adjustment within and across families.

BACKGROUND: Children in stepfamilies and single-parent families exhibit elevated levels of behavioural and emotional problems compared with children in intact (biological) families, but there is variation within and across these family types. AIMS: To examine the sources of variation in children's behavioural and emotional problems across diverse family settings. METHOD: Levels of behavioural and emotional problems in children from diverse stepfamilies and single-parent families were compared with children living with both biological parents. Psychosocial risks were measured at the individual child and family levels. RESULTS: Behavioural and emotional problems were elevated in children in stepmother/complex stepfamilies and single-parent families, but not in simple stepfather families, relative to 'biological' families. Psychopathology associated with family type was explained by compromised quality of the parent-child relationship, parental depression and socio-economic adversity. Sibling similarity in behavioural and emotional problems was most pronounced in high-risk family settings. CONCLUSIONS: Family type is a proxy for exposure to psychosocial risks; the extent of family-wide influence on children's development may be strongest in high-stress settings.

Adaptation, Psychological↗