Showing papers by "University of Newcastle published in 2003"

A Comparison of Outcomes With Angiotensin-Converting--Enzyme Inhibitors and Diuretics for Hypertension in the Elderly

Abstract: Background Treatment of hypertension with diuretics, beta-blockers, or both leads to improved outcomes. It has been postulated that agents that inhibit the renin–angiotensin system confer benefit beyond the reduction of blood pressure alone. We compared the outcomes in older subjects with hypertension who were treated with angiotensin-converting–enzyme (ACE) inhibitors with the outcomes in those treated with diuretic agents. Methods We conducted a prospective, randomized, open-label study with blinded assessment of end points in 6083 subjects with hypertension who were 65 to 84 years of age and received health care at 1594 family practices. Subjects were followed for a median of 4.1 years, and the total numbers of cardiovascular events in the two treatment groups were compared with the use of multivariate proportional-hazards models. Results At base line, the treatment groups were well matched in terms of age, sex, and blood pressure. By the end of the study, blood pressure had decreased to a similar exte...

IAHS Decade on Predictions in Ungauged Basins (PUB), 2003–2012: Shaping an exciting future for the hydrological sciences

Abstract: Drainage basins in many parts of the world are ungauged or poorly gauged, and in some cases existing measurement networks are declining. The problem is compounded by the impacts of human-induced changes to the land surface and climate, occur-ring at the local, regional and global scales. Predictions of ungauged or poorly gauged basins under these conditions are highly uncertain. The IAHS Decade on Predictions in Ungauged Basins, or PUB, is a new initiative launched by the International Association of Hydrological Sciences (IAHS), aimed at formulating and implementing appropriate science programmes to engage and energize the scientific community, in a coordinated manner, towards achieving major advances in the capacity to make predictions in ungauged basins. The PUB scientific programme focuses on the estimation of predictive uncertainty, and its subsequent reduction, as its central theme. A general hydrological prediction system contains three components: (a) a model that describes the key processes of interest, (b) a set of parameters that represent those landscape properties that govern critical processes, and (c) appropriate meteorological inputs (where needed) that drive the basin response. Each of these three components of the prediction system, is either not known at all, or at best known imperfectly, due to the inherent multi-scale space-time heterogeneity of the hydrological system, especially in ungauged basins. PUB will therefore include a set of targeted scientific programmes that attempt to make inferences about climatic inputs, parameters and model structures from available but inadequate data and process knowledge, at the basin of interest and/or from other similar basins, with robust measures of the uncertainties involved, and their impacts on predictive uncertainty. Through generation of improved understanding, and methods for the efficient quantification of the underlying multi-scale heterogeneity of the basin and its response, PUB will inexorably lead to new, innovative methods for hydrological predictions in ungauged basins in different parts of the world, combined with significant reductions of predictive uncertainty. In this way, PUB will demonstrate the value of data, as well as provide the information needed to make predictions in ungauged basins, and assist in capacity building in the use of new technologies. This paper presents a summary of the science and implementation plan of PUB, with a call to the hydrological community to participate actively in the realization of these goals.

Extinction vulnerability in marine populations

Abstract: Human impacts on the world's oceans have been substantial, leading to concerns about the extinction of marine taxa. We have compiled 133 local, regional and global extinctions of marine populations. There is typically a 53-year lag between the last sighting of an organism and the reported date of the extinction at whatever scale this has occurred. Most disappearances (80%) were detected using indirect historical comparative methods, which suggests that marine extinctions may have been underestimated because of low-detection power. Exploitation caused most marine losses at various scales (55%), followed closely by habitat loss (37%), while the remainder were linked to invasive species, climate change, pollution and disease. Several perceptions concerning the vulnerability of marine organisms appear to be too general and insufficiently conservative. Marine species cannot be considered less vulnerable on the basis of biological attributes such as high fecundity or large-scale dispersal characteristics. For commercially exploited species, it is often argued that economic extinction of exploited populations will occur before biological extinction, but this is not the case for non-target species caught in multispecies fisheries or species with high commercial value, especially if this value increases as species become rare. The perceived high potential for recovery, high variability and low extinction vulnerability of fish populations have been invoked to avoid listing commercial species of fishes under international threat criteria. However, we need to learn more about recovery, which may be hampered by negative population growth at small population sizes (Allee effect or depensation) or ecosystem shifts, as well as about spatial dynamics and connectivity of subpopulations before we can truly understand the nature of responses to severe depletions. The evidence suggests that fish populations do not fluctuate more than those of mammals, birds and butterflies, and that fishes may exhibit vulnerability similar to mammals, birds and butterflies. There is an urgent need for improved methods of detecting marine extinctions at various spatial scales, and for predicting the vulnerability of species.

The Hunter Serotonin Toxicity Criteria: simple and accurate diagnostic decision rules for serotonin toxicity.

Abstract: Background: There are difficulties with the diagnosis of serotonin toxicity, particularly with the use of Sternbach’s criteria. Aim: To improve the criteria for diagnosing clinically significant serotonin toxicity. Design: Retrospective analysis of prospectively collected data Methods: We studied all patients admitted to the Hunter Area Toxicology Service (HATS) following an overdose of a serotonergic drug from January 1987 to November 2002 ( n = 2222). Main outcomes were: diagnosis of serotonin toxicity by a clinical toxicologist, fulfilment of Sternbach’s criteria and treatment with a serotonin receptor (5-HT2A) antagonist. A learning dataset of 473 selective serotonin reuptake inhibitor (SSRI)-alone overdoses was used to determine individual clinical features predictive of serotonin toxicity by univariate analysis. Decision rules using CART analysis were developed, and tested on the dataset of all serotonergic overdose admissions. Results: Numerous clinical features were associated with serotonin toxicity, but only clonus (inducible, spontaneous or ocular), agitation, diaphoresis, tremor and hyperreflexia were needed for accurate prediction of serotonin toxicity as diagnosed by a clinical toxicologist. Although the learning dataset did not include patients with life-threatening serotonin toxicity, hypertonicity and maximum temperature > 38°C were universal in such patients; these features were therefore added. Using these seven clinical features, decision rules (the Hunter Serotonin Toxicity Criteria) were developed. These new criteria were simpler, more sensitive (84% vs. 75%) and more specific (97% vs. 96%) than Sternbach’s criteria. Discussion: These redefined criteria for serotonin toxicity should be more sensitive to serotonin toxicity and less likely to yield false positives.

Science Communication: A Contemporary Definition

Abstract: Science communication is a growing area of practice and research. During the past two decades, the number of activities, courses, and practitioners has steadily increased. But what actually is science communication? In what ways is it different to public awareness of science, public understanding of science, scientific culture, and scientific literacy? The authors review the literature to draw together a comprehensive set of definitions for these related terms. A unifying structure is presented and a contemporary definition of science communication positioned within this framework. Science communication (SciCom) is defined as the use of appropriate skills, media, activities, and dialogue to produce one or more of the following personal responses to science (the AEIOU vowel analogy): Awareness, Enjoyment, Interest, Opinion-forming, and Understanding. The definition provides an outcomes-type view of science communication, and provides the foundations for further research and evaluation.

Capital structure and financing of SMEs: Australian evidence

Abstract: This paper investigates the determinants of capital structure and use of financing for small and medium sized enterprises. Hypotheses utilising static trade-off and pecking order arguments are empirically examined using a series of firm characteristics including: size, asset structure, profitability, growth and risk. The hypotheses developed are tested using a large Australian nationwide panel survey. The results suggest that asset structure, profitability and growth are important determinants of capital structure and financing. For asset structure the direction of the influence is reliant upon the capital structure or financing measure employed. The results generally support static trade-off and pecking order arguments proposed by theoretical models.

Predicting obesity in early adulthood from childhood and parental obesity.

Abstract: OBJECTIVE: To determine the degree of tracking of adiposity from childhood to early adulthood, and the risk of overweight in early adulthood associated with overweight in childhood and parental weight status in a cohort of children born in the mid-1970s. DESIGN: Longitudinal observational study. SUBJECTS: Approximately 155 healthy boys and girls born in Adelaide, South Australia, 1975–1976 and their parents. MEASUREMENTS: Height and weight of subjects at 2 y, annually from 4 to 8 y, biennially from 11 to 15 y and at 20 y, and of parents when subjects were aged 8 y. Body mass index (BMI) of subjects converted to standard deviation scores and prevalence of overweight and obesity determined using worldwide definitions. Parents classified as overweight if BMI≥25 kg/m2. Tracking estimated as Pearson's correlation coefficient. Risk ratio used to describe the association between weight status at each age and parental weight status and weight status at 20 y and weight status at each earlier age, both unadjusted and adjusted for parental weight status. RESULTS: The prevalence of overweight/obesity increased with age and was higher than that reported in international reference populations. Tracking of BMI was established from 6 y onwards to 20 y at r-values >0.6, suggesting that BMI from 6 y is a good indicator of later BMI. Tracking was stronger for shorter intervals and for those subjects with both parents overweight compared with those with only one or neither parent overweight. Weight status at an earlier age was a more important predictor of weight status at 20 y than parental weight status, and risk of overweight at 20 y increased further with increasing weight status of parents. CONCLUSION: Strategies for prevention of overweight and targeted interventions for prevention of the progression of overweight to obesity are urgently required in school-aged children in order to stem the epidemic of overweight in the adult population.

The Gastrointestinal Tract

Abstract: The oesophagus extends from the pharynx at the level of the sixth cervical vertebra to the stomach at the level of T10. It lies in close relation to the aorta from T3 downwards and is behind the heart in the anterior/posterior plane from T5 to T10. It is lined by squamous epithelium.

Regulation of innate and adaptive immunity by the female sex hormones oestradiol and progesterone.

Abstract: Women mount more vigorous antibody- and cell-mediated immune responses following either infection or vaccination than men. The incidence of most autoimmune diseases is also higher in women than in men; however, during pregnancy many autoimmune diseases go into remission, only to flare again in the early post-partum period. Successful pregnancy requires that the female immune system tolerate the presence of a semi-allogeneic graft for 9 months. Oral contraceptive use can increase susceptibility to certain genital tract infections and sexually transmitted diseases in women. Moreover, treatment of mice and rats with female sex hormones is required to establish animal models of genital tract Chlamydia, Neisseria and Mycoplasma infection. This review describes what is currently known about the effects of the female sex hormones oestradiol and progesterone on innate and adaptive immune responses in order to provide a framework for understanding these sex differences. Data from both human and animal studies will be reviewed.

Statistical analysis of relativistic electron energies for cyclotron resonance with EMIC waves observed on CRRES

Abstract: Electromagnetic ion cyclotron (EMIC) waves which propagate at frequencies below the proton gyrofrequency can undergo cyclotron resonant interactions with relativistic electrons in the outer radiation belt and cause pitch-angle scattering and electron loss to the atmosphere. Typical storm-time wave amplitudes of 1-10 nT cause strong diffusion scattering which may lead to significant relativistic electron loss at energies above the minimum energy for resonance, E-min. A statistical analysis of over 800 EMIC wave events observed on the CRRES spacecraft is performed to establish whether scattering can occur at geophysically interesting energies (less than or equal to2 MeV). While E-min is well above 2 MeV for the majority of these events, it can fall below 2 MeV in localized regions of high plasma density and/or low magnetic field (f(pe)/f(ce,eq) > 10) for wave frequencies just below the hydrogen or helium ion gyrofrequencies. These lower energy scattering events, which are mainly associated with resonant L-mode waves, are found within the magnetic local time range 1300 4.5. The average wave spectral intensity of these events (4-5 nT(2)/Hz) is sufficient to cause strong diffusion scattering. The spatial confinement of these events, together with the limited set of these waves that resonate with less than or equal to2 MeV electrons, suggest that these electrons are only subject to strong scattering over a small fraction of their drift orbit. Consequently, drift-averaged scattering lifetimes are expected to lie in the range of several hours to a day. EMIC wave scattering should therefore significantly affect relativistic electron dynamics during a storm. The waves that resonate with the similar toMeV electrons are produced by low-energy (similar tokeV) ring current protons, which are expected to be injected into the inner magnetosphere during enhanced convection events.

Phloem loading and unloading of sugars and amino acids

Abstract: In terrestrial higher plants, phloem transport delivers most nutrients required for growth and storage processes. Some 90% of plant biomass, transported as sugars and amino nitrogen (N) compounds in a bulk flow of solution, is propelled though the phloem by osmotically generated hydrostatic pressure differences between source (net nutrient export) and sink (net nutrient import) ends of phloem paths. Source loading and sink unloading of sugars, amino N compounds and potassium largely account for phloem sap osmotic concentrations and hence pressure differences. A symplasmic component is characteristic of most loading and unloading pathways which, in some circumstances, may be interrupted by an apoplasmic step. Raffinose series sugars appear to be loaded symplasmically. However, sucrose, and probably certain amino acids, are loaded into minor veins from source leaf apoplasms by proton symporters localized to plasma membranes of their sieve element/companion cell (se/cc) complexes. Sucrose transporters, with complementary kinetic properties, are conceived to function as membrane transporter complexes that respond to alterations in source/sink balance. In contrast, symplasmic unloading is common for many sink types. Intervention of an apoplasmic step, distal from importing phloem, is reserved for special situations. Effluxers that release sucrose and amino acids to the surrounding apoplasm in phloem loading and unloading are yet to be cloned. The physiological behaviour of effluxers is consistent with facilitated membrane transport that can be energy coupled. Roles of sucrose and amino acid transporters in phloem unloading remain to be discovered along with mechanisms regulating symplasmic transport. The latter is hypothesized to exert significant control over phloem unloading and, in some circumstances, phloem loading.

Direct numerical simulations of turbulent channel flow with transverse square bars on one wall

Abstract: Direct numerical simulations have been carried out for a fully developed turbulent channel flow with a smooth upper wall and a lower wall consisting of square bars separated by a rectangular cavity. A wide range of of the Clauser roughness function reflects that of the form drag.

Multi‐decadal variability of flood risk

Abstract: Recent research has highlighted the persistence of multi-decadal epochs of enhanced/reduced flood risk across New South Wales (NSW), Australia. Recent climatological studies have also revealed multi-decadal variability in the modulation of the magnitude of El Nin椀/Southern Oscillation (ENSO) impacts. In this paper, the variability of flood risk across NSW is analysed with respect to the observed modulation of ENSO event magnitude. This is achieved through the use of a simple index of regional flood risk. The results indicate that cold ENSO events (La Nin和) are the dominant drivers of elevated flood risk. An analysis of multidecadal modulation of flood risk is achieved using the interdecadal Pacific Oscillation (IPO) index. The analysis reveals that IPO modulation of ENSO events leads to multi-decadal epochs of elevated flood risk, however this modulation appears to affect not only the magnitude of individual ENSO events, but also the frequency of their occurrence. This dual modulation of ENSO processes has the effect of reducing and elevating flood risk on multi-decadal timescales. These results have marked implications for achieving robust flood frequency analysis as well as providing a strong example of the role of natural climate variability.

Radiosensitization and DNA Repair Inhibition by the Combined Use of Novel Inhibitors of DNA-dependent Protein Kinase and Poly(ADP-Ribose) Polymerase-1

Abstract: The DNA repair enzymes, DNA-dependent protein kinase (DNA-PK) and poly(ADP-ribose) polymerase-1 (PARP-1), are key determinants of radio- and chemo-resistance. We have developed and evaluated novel specific inhibitors of DNA-PK (NU7026) and PARP-1 (AG14361) for use in anticancer therapy. PARP-1- and DNA-PK-deficient cell lines were 4-fold more sensitive to ionizing radiation (IR) alone, and showed reduced potentially lethal damage recovery (PLDR) in G(0) cells, compared with their proficient counterparts. NU7026 (10 micro M) potentiated IR cytotoxicity [potentiation factor at 90% cell kill (PF(90)) = 1.51 +/- 0.04] in exponentially growing DNA-PK proficient but not deficient cells. Similarly, AG14361 (0.4 micro M) potentiated IR in PARP-1(+/+) (PF(90) = 1.37 +/- 0.03) but not PARP-1(-/-) cells. When NU7026 and AG14361 were used in combination, their potentiating effects were additive (e.g., PF(90) = 2.81 +/- 0.19 in PARP-1(+/+) cells). Both inhibitors alone reduced PLDR approximately 3-fold in the proficient cell lines. Furthermore, the inhibitor combination completely abolished PLDR. IR-induced DNA double strand break (DNA DSB) repair was inhibited by both NU7026 and AG14361, and use of the inhibitor combination prevented 90% of DNA DSB rejoining, even 24-h postirradiation. Thus, there was a correlation between the ability of the inhibitors to prevent IR-induced DNA DSB repair and their ability to potentiate cytotoxicity. Thus, individually, or in combination, the DNA-PK and PARP-1 inhibitors act as potent radiosensitizers and show potential as tools for anticancer therapeutic intervention.

New primers for the class Actinobacteria: application to marine and terrestrial environments.

Abstract: In this study, we redesigned and evaluated primers for the class Actinobacteria In silico testing showed that the primers had a perfect match with 82% of genera in the class Actinobacteria, representing a 26-213% improvement over previously reported primers Only 4% of genera that displayed mismatches did so in the terminal three bases of the 3' end, which is most critical for polymerase chain reaction success The primers, designated S-C-Act-0235-a-S-20 and S-C-Act-0878-a-A-19, amplified an approximately 640 bp stretch of the 16S rRNA gene from all actinobacteria tested (except Rubrobacter radiotolerans) up to an annealing temperature of 72 degrees C An Actinobacteria Amplification Resource (http://microbe2nclacuk/MMB/AARhtm) was generated to provide a visual guide to aid the amplification of actinobacterial 16S rDNA Application of the primers to DNA extracted from marine and terrestrial samples revealed the presence of actinobacteria that have not been described previously The use of 16S rDNA similarity and DNA-DNA pairing correlations showed that almost every actinomycete clone represented either a new species or a novel genus The results of this study reinforce the proposition that current culture-based techniques drastically underestimate the diversity of Actinobacteria in the environment and highlight the need to evaluate taxon-specific primers regularly in line with improvements in databases holding 16S rDNA sequences

Synergistic and antagonistic interactions of anticholinesterase terpenoids in Salvia lavandulaefolia essential oil

Abstract: In vitro anticholinesterase activities of eight commercially available terpenoid constituents of Salvia lavandulaefolia have been investigated. These included 1,8-cineole, camphor, alpha-pinene, beta-pinene, borneol, caryophyllene oxide, linalool and bornyl acetate. Dose-dependent inhibition of acetylcholinesterase (AChE) by these chemical constituents was determined using the method of Ellman [Biochem. Pharmacol. 7 (1961) 88]. The IC50 value of 1,8-cineole was 0.06+/-0.01 mg/ml similar to that of the essential oil (0.05+/-0.01 mg/ml). Analyses of the expected inhibitions based on the prediction of a zero interactive response of a combination at its naturally occurring ratios were carried out in comparison with observed inhibition. Minor synergy was apparent in 1,8-cineole/alpha-pinene and 1,8-cineole/caryophyllene oxide combinations, with interaction indexes not exceeding 0.5. In contrast, a combination of camphor and 1,8-cineole was antagonistic with an interaction index of 2. A combination of all eight compounds was zero interactive. A combination of six constituents, excluding 1,8-cineole and camphor, was used to compare the method of expected response of a combination with a method of summation. These findings reveal that the inhibitory activity of the oil results from a complex interaction between its constituents, which produce both synergistic and antagonistic responses between the component terpenes. Understanding such interactions is important in comparing species on the basis of chemical composition.

Outcome in adults with juvenile idiopathic arthritis: a quality of life study.

Abstract: Objective To evaluate quality of life (QOL) in adults with juvenile idiopathic arthritis (JIA), using validated measures of functional disability and generic health status, and to quantify their educational attainment and employment status. Methods The adult rheumatology departmental database was used to identify patients. Functional disability and generic health status/QOL were assessed by the Health Assessment Questionnaire (HAQ) and the Short Form 36-item health profile (SF-36), respectively. Educational achievement and employment status were assessed by questionnaire. Results Complete data were available for 82 of the 101 patients identified. The median age of patients was 30 years, and the median disease duration was 21 years. No deaths were recorded. All subtypes of JIA were represented. Thirty-nine percent of patients had active disease (based on the physician global assessment scale score). The median HAQ score was 1.125 (range 0–3). SF-36 scores for bodily pain, general health, physical functioning, vitality, emotion, and social isolation were significantly worse in patients compared with controls, and this trend increased with increasing age of the patients and disease duration. The SF-36 mental summation scores of patients were low compared with those of controls, for all subtypes of JIA, and this finding was independent of the degree of functional disability (by HAQ and SF-36 physical summation scores). The educational attainment of patients was comparable to that of local controls, but unemployment rates for patients were 3-fold higher than those for controls. Conclusion This is the largest study in which the SF-36 was used to assess generic health status and QOL in adults with JIA. Many patients had active disease in adulthood, and although the physical outcome of adults with JIA is relatively good, a profound effect on generic health status and QOL was demonstrated for all types of JIA. Furthermore, despite excellent educational attainment, there was a high rate of unemployment among patients.

A survey of recent innovations in vibration damping and control using shunted piezoelectric transducers

Abstract: Research on shunted piezoelectric transducers, performed mainly over the past decade, has generated new opportunities for control of vibration and damping in flexible structures. This is made possible by the strong electromechanical coupling associated with modern piezoelectric transducers. In vibration control applications, a piezoelectric transducer is bonded to, or embedded in a base structure. As the structure deforms, the piezoelectric element strains and converts a portion of the structural vibration energy into electrical energy. By shunting the piezoelectric transducer to an electrical impedance, a part of the induced electrical energy can be dissipated. Hence, the impedance acts as a means of extracting mechanical energy from the base structure. This paper reviews recent research related to the use of shunted piezoelectric elements for vibration damping and control. In particular, the paper presents an overview of the literature on piezoelectric shunt damping and discusses recent observations on the feedback nature of piezoelectric shunt damping systems.

Cervical transforaminal injection of corticosteroids into a radicular artery: a possible mechanism for spinal cord injury.

Abstract: Spinal cord injury has been recognized as a complication of cervical transforaminal injections, but the mechanism of injury is uncertain. In the course of a transforaminal injection, an observation was made after the initial injection of contrast medium. The contrast medium filled a radicular artery that passed to the spinal cord. The procedure was summarily abandoned, and the patient suffered no ill effects. This case demonstrates that despite using careful and accurate technique, it is possible for material to be injected into a radicular artery. Consequently, inadvertent injection of corticosteroids into a radicular artery may be the mechanism for spinal cord injury following transforaminal injections. This observation warns operators to always perform a test injection of contrast medium, and carefully check for arterial filling using real-time fluoroscopy with digital subtraction.