Colloidal 2D Mo1-xWxS2 nanosheets: an atomic- to ensemble-level spectroscopic study

Composition dependent tuning of electronic and optical properties in semiconducting two-dimensional (2D) transition metal dichalcogenide (TMDC) alloys is promising for tailoring the materials for optoelectronics. Here, we report a solution-based synthesis suitable to obtain predominantly monolayered 2D semiconducting Mo1-xWxS2 nanosheets (NSs) with controlled composition as substrate-free colloidal inks. Atomic-level structural analysis by high-angle annular dark-field (HAADF) scanning transmission electron microscopy (STEM) coupled with energy dispersive X-ray spectroscopy (EDXS) depicts the distribution of individual atoms within the Mo1-xWxS2 NSs and reveals the tendency for domain formation, especially at low molar tungsten fractions. These domains cause a broadening in the associated ensemble-level Raman spectra, confirming the extrapolation of the structural information from the microscopic scale to the properties of the entire sample. A characterization of the Mo1-xWxS2 NSs by steady-state optical spectroscopy shows that a band gap tuning in the range of 1.89-2.02 eV (614-655 nm) and a spin-orbit coupling-related exciton splitting of 0.16-0.38 eV can be achieved, which renders colloidal methods viable for upscaling low cost synthetic approaches toward application-taylored colloidal TMDCs.

Electronic Structure of Colloidal 2H-MoS2 Mono and Bilayers Determined by Spectroelectrochemistry

The electronic structure of mono and bilayers of colloidal 2H-MoS₂ nanosheets synthesized by wet-chemistry using potential-modulated absorption spectroscopy (EMAS), differential pulse voltammetry, and electrochemical gating measurements is investigated. The energetic positions of the conduction and valence band edges of the direct and indirect bandgap are reported and observe strong bandgap renormalization effects, charge screening of the exciton, as well as intrinsic n-doping of the as-synthesized material. Two distinct transitions in the spectral regime associated with the C exciton are found, which overlap into a broad signal upon filling the conduction band. In contrast to oxidation, the reduction of the nanosheets is largely reversible, enabling potential applications for reductive electrocatalysis. This work demonstrates that EMAS is a highly sensitive tool for determining the electronic structure of thin films with a few nanometer thicknesses and that colloidal chemistry affords high-quality transition metal dichalcogenide nanosheets with an electronic structure comparable to that of exfoliated samples.

Enhanced growth factor expression in chronic diabetic wounds treated by cold atmospheric plasma

AIMS

Cold atmospheric plasma (CAP) has been proven to enhance wound healing in superficial, chronically infected, diabetic foot ulcers. We aimed to investigate the molecular drivers responsible for this macroscopically observed improvement in diabetic wound healing.

METHODS

Wound exudate was available from each change of dressing within a prospective, randomised, patient-blinded clinical trial. Specific protein level analyses were conducted via multiplex ELISA for wound samples of a representative subcohort (placebo: n = 13; CAP: n = 14). Expression of fibroblast growth factor 2 (FGF-2), vascular endothelial growth factor A (VEGF-A), cytokines and matrix metalloproteinases (MMPs) were evaluated over a treatment period of about 14 days.

RESULTS

Analysis revealed increased levels of the growth factors FGF-2 (placebo: median 46.9 range [32.0-168.6] AU vs. CAP: 113.7[55.8-208.1] AU) and VEGF-A (placebo: 79.7 [52.4-162.7] AU vs. CAP: 120.8 [51.1-198.1] AU) throughout the treatment period and in head-to-head comparison in a daily assessment. CAP-treated wounds showed increased levels of tumour necrosis factor-alpha, interleukins 1α and 8. However, the total protein amounts were not significantly elevated. The total protein amounts of MMPs were not altered by CAP.

CONCLUSIONS

Induction of crucial growth factors, like FGF-2 and VEGF-A, and interleukins appears to be an important component of CAP-mediated promotion of granulation, vascularisation and reepithelialisation in the diabetic foot. These findings demonstrate for the first time that CAP-mediated growth factor induction also occurs in persons with diabetes, as previously described only in several in vitro and rodent experiments. Clinical Trial registration KPWTRIAL: NCT04205942, ClinicalTrials.gov.

Spatially resolved fluorescence of caesium lead halide perovskite supercrystals reveals quasi-atomic behavior of nanocrystals

We correlate spatially resolved fluorescence (-lifetime) measurements with X-ray nanodiffraction to reveal surface defects in supercrystals of self-assembled cesium lead halide perovskite nanocrystals and study their effect on the fluorescence properties. Upon comparison with density functional modeling, we show that a loss in structural coherence, an increasing atomic misalignment between adjacent nanocrystals, and growing compressive strain near the surface of the supercrystal are responsible for the observed fluorescence blueshift and decreased fluorescence lifetimes. Such surface defect-related optical properties extend the frequently assumed analogy between atoms and nanocrystals as so-called quasi-atoms. Our results emphasize the importance of minimizing strain during the self-assembly of perovskite nanocrystals into supercrystals for lighting application such as superfluorescent emitters.

By utilizing spatially resolved fluorescence (-lifetime) measurements and high precision X-ray nanodiffraction, the authors correlate the influence of structural misalignment and fluorescence (-lifetime) properties of all-inorganic CsPbX₃ (X^– = Br^–, Cl^–) perovskite superlattices.

Periodic Fluorescence Variations of CdSe Quantum Dots Coupled to Aryleneethynylenes with Aggregation-Induced Emission

CdSe nanocrystals and aggregates of an aryleneethynylene derivative are assembled into a hybrid thin film with dual fluorescence from both fluorophores. Under continuous excitation, the nanocrystals and the molecules exhibit anticorrelated fluorescence intensity variations, which become periodic at low temperature. We attribute this to a structure-dependent aggregation-induced emission of the aryleneethynylene derivative, which impacts the rate of excitation energy transfer between the molecules and nanocrystals. This work highlights that combining semiconductor nanocrystals with molecular aggregates, which exhibit aggregation-induced emission, can result in emerging optical properties.

Effect of Cold Atmospheric Plasma Therapy vs Standard Therapy Placebo on Wound Healing in Patients With Diabetic Foot Ulcers: A Randomized Clinical Trial

IMPORTANCE

Diabetic foot ulcers are a common complication of diabetes and require specialized treatment. Cold atmospheric plasma (CAP) has been associated with benefits in wound infection and healing in previous smaller series of case reports. Yet the effect of CAP compared with standard care therapy in wound healing in diabetic foot ulcers remains to be studied.

OBJECTIVE

To determine whether the application of CAP accelerates wound healing in diabetic foot ulcers compared with standard care therapy.

DESIGN, SETTING, AND PARTICIPANTS

A prospective, randomized, placebo-controlled, patient-blinded clinical trial was conducted at 2 clinics with recruitment from August 17, 2016, to April 20, 2019. Patients were scheduled to remain in follow-up until April 30, 2024. Patients with diabetes and diabetic foot ulcers described using the combined Wagner-Armstrong classification of 1B or 2B (superficial or infected diabetic foot ulcers extending to tendon) were eligible. A patient could participate with 1 or more wounds in both groups in both intervention and control groups. Wounds were randomized separately, allowing a participant to be treated several times within the study following a 2 × 2 × 2 randomization strata considering sex, smoking status, and age (≤68 years and >68 years).

INTERVENTIONS

Standard care treatment with 8 applications of either CAP generated from argon gas in an atmospheric pressure plasma jet or 8 applications of placebo treatment in a patient-blinded manner.

MAIN OUTCOMES AND MEASURES

Primary end points were reduction in wound size, clinical infection, and microbial load compared with treatment start. Secondary end points were time to relevant wound reduction (>10%), reduction of infection, parameters of patient's well-being, and treatment-associated adverse events.

RESULTS

Of 65 diabetic foot ulcer wounds from 45 patients assessed for study, 33 wounds from 29 patients were randomized to CAP and 32 wounds from 28 to placebo, with 62 wounds from 43 patients (31 wounds per group) included for final evaluation (mean [SD] age, 68.5 [9.1] years for full sample). Four patients with 5 wounds of 31 (16.1%) wounds in the CAP group and 3 patients with 4 wounds of 31 (13%) wounds in the placebo group were active smokers. CAP therapy yielded a significant increase in wound healing, both in total mean (SD) area reduction (CAP vs placebo relative units, -26.31 [11.72]; P = .03) and mean (SD) time to relevant wound area reduction (CAP vs placebo relative units, 10% from baseline, 1.60 [0.58]; P = .009). Reduction of infection and microbial load was not significantly different between CAP and placebo. No therapy-related adverse events occurred during therapy; patient's perceptions during therapy were comparable.

CONCLUSIONS AND RELEVANCE

In this randomized clinical trial, CAP therapy resulted in beneficial effects in chronic wound treatment in terms of wound surface reduction and time to wound closure independent from background infection.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04205942.

Fast, Infrared-Active Optical Transistors Based on Dye-Sensitized CdSe Nanocrystals

We report an optically gated transistor composed of CdSe nanocrystals (NCs), sensitized with the dye zinc β-tetraaminophthalocyanine for operation in the first telecom window. This device shows a high ON/OFF ratio of 6 orders of magnitude in the red spectral region and an unprecedented 4.5 orders of magnitude at 847 nm. By transient absorption spectroscopy, we reveal that this unexpected infrared sensitivity is due to electron transfer from the dye to the CdSe NCs within 5 ps. We show by time-resolved photocurrent measurements that this enables fast rise times during near-infrared optical gating of 47 ± 11 ns. Electronic coupling and accelerated nonradiative recombination of charge carriers at the interface between the dye and the CdSe NCs are further corroborated by steady-state and time-resolved photoluminescence measurements. Field-effect transistor measurements indicate that the increase in photocurrent upon laser illumination is mainly due to the increase in the carrier concentration while the mobility remains unchanged. Our results illustrate that organic dyes as ligands for NCs invoke new optoelectronic functionalities, such as fast optical gating at sub-bandgap optical excitation energies.

Inhalational versus Propofol-Based Total Intravenous Anaesthesia: Practice Patterns and Perspectives among Australasian Anaesthetists

Increasing evidence suggests that total intravenous anaesthesia (TIVA) may be the preferred anaesthetic for cancer resection surgery. To assist the preparation of a randomised controlled trial (RCT) examining Volatile (versus TIVA) Anaesthesia and Perioperative Outcomes Related to Cancer (VAPOR-C) we developed an 18-question electronic survey to investigate practice patterns and perspectives (emphasising indications, barriers, and impact on cancer outcomes) of TIVA versus inhalational general anaesthesia in Australasia. The survey was emailed to 1,000 (of 5,300 active Fellows) randomly selected Australian and New Zealand College of Anaesthetists (ANZCA) Fellows. The response rate was 27.5% (n=275). Of the respondents, 18% use TIVA for the majority of cases. In contrast, 46% use TIVA 20% of the time or less. Respondents described indications for TIVA as high risk of nausea, neurosurgery, and susceptibility to malignant hyperthermia. Lack of equipment, lack of education and cost were not considered barriers to TIVA use, and a significant proportion (41%) of respondents would use TIVA more often if setup were easier. Of the respondents, 43% thought that TIVA was associated with less cancer recurrence than inhalational anaesthesia, while 46% thought that there was no difference. Yet, only 29% of respondents reported that they use TIVA often or very often for cancer surgery. In Australasia, there is generally a low frequency of TIVA use despite a perception of benefit when compared with inhalational anaesthesia. Anaesthetists are willing to use TIVA for indications where sufficient evidence supports a meaningful level of improvement in clinical outcome. The survey explores attitudes towards use of TIVA for cancer surgery and demonstrates equipoise in anaesthetists’ opinions regarding this indication. The inconsistent use of TIVA in Australasia, minimal barriers to its use, and the equipoise in anaesthetists’ opinions regarding the effect of TIVA versus inhalational anaesthesia on cancer outcomes support the need for a large prospective RCT.

Effect of beta-blockers on cancer recurrence and survival: a meta-analysis of epidemiological and perioperative studies

BACKGROUND

The biological perturbation associated with psychological and surgical stress is implicated in cancer recurrence. Preclinical evidence suggests that beta-blockers can be protective against cancer progression. We undertook a meta-analysis of epidemiological and perioperative clinical studies to investigate the association between beta-blocker use and cancer recurrence (CR), disease-free survival (DFS), and overall survival (OS).

METHODS

Databases were searched until September 2017, reported hazard ratios (HRs) pooled, and 95% confidence intervals (CIs) calculated. Comparative studies examining the effect of beta-blockers (selective and non-selective) on cancer outcomes were included. The Newcastle Ottawa Scale was used to assess methodological quality and bias.

RESULTS

Of the 27 included studies, nine evaluated the incidental use of non-selective beta-blockers, and ten were perioperative studies. Beta-blocker use had no effect on CR. Within subgroups of cancer, melanoma was associated with improved DFS (HR 0.03, 95% CI 0.01-0.17) and OS (HR 0.04, 95% CI 0.00-0.38), while endometrial cancer had an associated reduction in DFS (HR 1.40, 95% CI 1.10-1.80) and OS (HR 1.50, 95% CI 1.12-2.00). There was also reduced OS seen with head and neck and prostate cancer. Non-selective beta-blocker use was associated with improved DFS and OS in ovarian cancer, improved DFS in melanoma, but reduced OS in lung cancer. Perioperative studies showed similar variable effects across cancer types, albeit from a limited data pool.

CONCLUSION

Beta-blocker use had no evident effect on CR. The beneficial effect of beta-blockers on DFS and OS in the epidemiological or perioperative setting remains variable, tumour-specific, and of low-level evidence at present.

Relevance of chronic hepatitis E in liver transplant recipients: a real-life setting

The chronic course of hepatitis E virus (HEV) infections in orthotopic liver transplant (OLT) recipients has been described previously, but prospectively collected data are rare. We aimed to study the role of chronic hepatitis E in OLT in a real-life setting. Therefore, 287 adult OLT recipients (169 male [59%], median age 56 years) were prospectively tested by HEV polymerase chain reaction assay (lower level of detection = 10 IU/mL), irrespective of their level of liver enzymes. In 4 patients (1.4%), chronic HEV infection was diagnosed. All 4 patients were male, and their age (median 48.5 years), the time since transplantation (median 45.5 months), and bilirubin level (median 0.6 mg/dL) did not differ significantly from the total cohort. However, alanine transaminase and aspartame transaminase levels were significantly higher in HEV-infected patients (75-646 U/L, median 216 U/L and 68-317 U/L, median 108 U/L) than in non-infected patients (6-617 U/L, median 41 and 6-355 U/L, median 36; P = 0.004 and 0.040, Mann-Whitney test). In 3 patients, liver biopsy was performed and revealed signs of inflammation and chronic liver disease, as enlarged densely infiltrated portal tracts with mild-to-moderate interface hepatitis. All infected patients were treated with ribavirin with the starting dose adjusted to renal function (400-800 mg/day). In 2 patients, dose reduction was necessary. Transaminases normalized in all 4 patients, and all patients cleared their infection within 3 months of ribavirin treatment. However, 1 patient experienced viral relapse 12 weeks after discontinuation. Ribavirin medication was re-started and viral clearance occurred within 8 weeks and persisted. Sequence analysis of the HEV genome of this patient revealed that he was infected with an HEV variant, which recently has been shown to have a reduced response to ribavirin in cell culture. The risk of chronic HEV infections in OLT recipients in low-endemic countries should not be overestimated. No case of chronic hepatitis E was observed in patients with normal liver enzymes, indicating that general screening of all OLT recipients is not necessary. However, if chronic hepatitis E develops, it can be treated efficiently with ribavirin.

Symmetrically reduced stiffness and increased extensibility in compression and tension at the mineralized fibrillar level in rachitic bone

In metabolic bone diseases, the alterations in fibrillar level bone-material quality affecting macroscopic mechanical competence are not well-understood quantitatively. Here, we quantify the fibrillar level deformation in cantilever bending in a mouse model for hereditary rickets (Hpr). Microfocus in-situ synchrotron small-angle X-ray scattering (SAXS) combined with cantilever bending was used to resolve nanoscale fibril strain in tensile- and compressive tissue regions separately, with quantitative backscattered scanning electron microscopy used to measure microscale mineralization. Tissue-level flexural moduli for Hpr mice were significantly (p<0.01) smaller compared to wild-type (~5 to 10-fold reduction). At the fibrillar level, the fibril moduli within the tensile and compressive zones were significantly (p<0.05) lower by ~3- to 5-fold in Hpr mice compared to wild-type mice. Hpr mice have a lower mineral content (24.2±2.1Cawt.% versus 27.4±3.3Ca wt.%) and its distribution was more heterogeneous compared to wild-type animals. However, the average effective fibril modulus did not differ significantly (p>0.05) over ages (4, 7 and 10weeks) between tensile and compressive zones. Our results indicate that incompletely mineralized fibrils in Hpr mice have greater deformability and lower moduli in both compression and tension, and those compressive and tensile zones have similar moduli at the fibrillar level.

A study on evaluation strategies in dimensional X-ray computed tomography by estimation of measurement uncertainties

Computed tomography has entered the industrial world in 1980’s as a technique for non-destructive testing and has nowadays become a revolutionary tool for dimensional metrology, suitable for actual/nominal comparison and verification of geometrical and dimensional tolerances. This paper evaluates measurement results using different measuring strategies applied in different inspection software packages for volume and surface data analysis. The strategy influence is determined by calculating the measurement uncertainty. This investigation includes measurements of two industrial items, an aluminium pipe connector and a plastic toggle, a hearing aid component. These are measured using a commercial CT scanner. Traceability is transferred using tactile and optical coordinate measuring machines, which are used to produce reference measurements. Results show that measurements of diameter for both parts resulted in smaller systematic errors compared to distance and height measurements. It was found that uncertainties of all measurands evaluated on surface data were generally greater compared to measurements performed on volume data.

Hypophosphatemic rickets is associated with disruption of mineral orientation at the nanoscale in the flat scapula bones of rachitic mice with development

Metabolic bone disorders such as rickets are associated with altered in vivo muscular force distributions on the skeletal system. During development, these altered forces can potentially affect the spatial and temporal dynamics of mineralised tissue formation, but the exact mechanisms are not known. Here we have used a murine model of hypophosphatemic rickets (Hpr) to study the development of the mineralised nanostructure in the intramembranously ossifying scapulae (shoulder bone). Using position-resolved scanning small angle X-ray scattering (SAXS), we quantified the degree and direction of mineral nanocrystallite alignment over the width of the scapulae, from the load bearing lateral border (LB) regions to the intermediate infraspinous fossa (IF) tissue. These measurements revealed a significant (p<0.05) increase in mineral nanocrystallite alignment in the LB when compared to the IF region, with increased tissue maturation in wild-type mice; this was absent in mice with rickets. The crystallites were more closely aligned to the macroscopic bone boundary in the LB when compared to the IF region in both wild type and Hpr mice, but the degree of alignment was reduced in Hpr mice. These findings are consistent with a correlation between the nanocrystallites within fibrils and in vivo muscular forces. Thus our results indicate a relevant mechanism for the observed increased macroscopic deformability in rickets, via a significant alteration in the mineral particle alignment, which is mediated by an altered spatial distribution of muscle forces.

A Retrospective Observational Study Examining the Admission Arterial to End-Tidal Carbon Dioxide Gradient in Intubated Major Trauma Patients

Major trauma patients who are intubated and ventilated are exposed to the potential risk of iatrogenic hypercapnic and hypocapnic physiological stress. In the pre-hospital setting, end-tidal capnography is used as a practical means of estimating arterial carbon dioxide concentrations and to guide the adequacy of ventilation. In our study, potentially deleterious hypercapnia (mean 47 mmHg, range 26 to 83 mmHg) due to hypoventilation was demonstrated in 49% of 100 intubated major trauma patients arriving at a major Australian trauma centre. A mean gradient of 15 mmHg arterial to end-tidal carbon dioxide concentration difference was found, highlighting the limitations of capnography in this setting. Moreover, 80% of the patients in the study had a head injury. Physiological deadspace due to hypovolaemia in these patients is commonly thought to contribute to the increased arterial to end-tidal carbon dioxide gradient in trauma patients. However in this study, scene and arrival patient hypoxia was more predictive of hypoventilation and an increased arterial to end-tidal carbon dioxide gradient than physiological markers of shock. Greater vigilance for hypercapnia in intubated trauma patients is required. Additionally, a larger study may confirm that lower end-tidal carbon dioxide levels could be safely targeted in the pre-hospital and emergency department ventilation strategies of the subgroup of major trauma patients with scene hypoxia.

Genetic discontinuity between local hunter-gatherers and central Europe's first farmers

After the domestication of animals and crops in the Near East some 11,000 years ago, farming had reached much of central Europe by 7500 years before the present. The extent to which these early European farmers were immigrants or descendants of resident hunter-gatherers who had adopted farming has been widely debated. We compared new mitochondrial DNA (mtDNA) sequences from late European hunter-gatherer skeletons with those from early farmers and from modern Europeans. We find large genetic differences between all three groups that cannot be explained by population continuity alone. Most (82%) of the ancient hunter-gatherers share mtDNA types that are relatively rare in central Europeans today. Together, these analyses provide persuasive evidence that the first farmers were not the descendants of local hunter-gatherers but immigrated into central Europe at the onset of the Neolithic.

Persistent genital arousal disorder: a review of the literature and recommendations for management

Persistent genital arousal disorder is a newly recognized condition that is poorly understood. There is a paucity of research in this area and there are concerns as to the validity of the results of what little research there has been. This article aims to draw together current literature on this topic and provide readers with guidance on the management of this condition. This includes a working definition, an exploration of possible aetiologies within the confines of current knowledge, practical advice regarding assessment, management and auditable outcomes of practice.

Microfocus small angle X-ray scattering reveals structural features in archaeological bone samples: detection of changes in bone mineral habit and size

Microfocus X-ray scattering provides a powerful nondestructive technique capable of providing important information about the size, habit, and arrangement of mineral crystals in bone. The technique is capable of probing textural differences in a sample at a micron scale resolution. The study presented here involved the analysis of a number of archaeological bones by microfocus X-ray scattering at the ESRF Grenoble in order to determine local changes in mineral durability. The results showed that regions of bone with a modified microscopic morphology contained a greater dispersion of crystal shape when compared with more intact regions and control contemporary bone samples, but the crystal thickness values showed similar consistency. We speculate that the persistence of collagen in the archaeological bone may allow diagenetic remodeling of bone in terms of crystallite shape but defines the size of remodelled crystallites. The ability to detect such local changes in texture has wide potential for determining crystal characteristics in healthy and diseased bone samples.

Automatic identification of gray matter structures from MRI to improve the segmentation of white matter lesions

The segmentation of MRI scans of patients with white matter lesions (WML) is difficult because the MRI characteristics of WML are similar to those of gray matter. Intensity-based statistical classification techniques misclassify some WML as gray matter and some gray matter as WML. We developed a fast elastic matching algorithm that warps a reference data set containing information about the location of the gray matter into the approximate shape of the patient's brain. The region of white matter was segmented after segmenting the cortex and deep gray matter structures. The cortex was identified by using a three-dimensional, region-growing algorithm that was constrained by anatomical, intensity gradient, and tissue class parameters. White matter and WML were then segmented without interference from gray matter by using a two-class minimum-distance classifier. Analysis of double-echo spin-echo MRI scans of 16 patients with clinically determined multiple sclerosis (MS) was carried out. The segmentation of the cortex and deep gray matter structures provided anatomical context. This was found to improve the segmentation of MS lesions by allowing correct classification of the white matter region despite the overlapping tissue class distributions of gray matter and MS lesion.

Variation in mortality rates in Australia: correlation with Indigenous status, remoteness and socio-economic deprivation

BACKGROUND

The aim of this study was to study ecological correlations between age-adjusted all-cause mortality rates in Australian statistical divisions and (1) the proportion of residents that self-identify as Indigenous, (2) remoteness, and (3) socio-economic deprivation.

METHODS

All-cause mortality rates for 57 statistical divisions were calculated and directly standardized to the 1997 Australian population in 5-year age groups using Australian Bureau of Statistics (ABS) data. The proportion of residents who self-identified as Indigenous was obtained from the 1996 Census. Remoteness was measured using ARIA (Accessibility and Remoteness Index for Australia) values. Socioeconomic deprivation was measured using SEIFA (Socio-Economic Index for Australia) values from the ABS.

RESULTS

Age-standardized all-cause mortality varies two-fold from 5.7 to 11.3 per 1,000 across Australian statistical divisions. Strongest correlation was between Indigenous status and mortality (r = 0.69, p < 0.001). Correlation between remoteness and mortality was modest (r = 0.39, p = 0.002) as was correlation between socio-economic deprivation and mortality (r = -0.42, p = 0.001). Excluding the three divisions with the highest mortality, a multiple regression model using the logarithm of the adjusted mortality rate as the dependent variable showed that the partial correlation (and hence proportion of the variance explained) for Indigenous status was 0.03 (9 per cent; p = 0.03), for SEIFA score was -0.17 (3 per cent; p = 0.22); and for remoteness was -0.22 (5 per cent; p = 0.13). Collectively, the three variables studied explain 13 per cent of the variability in mortality.

CONCLUSIONS

Ecological correlation exists between all-cause mortality, Indigenous status, remoteness and disadvantage across Australia. The strongest correlation is with Indigenous status, and correlation with all three characteristics is weak when the three statistical divisions with the highest mortality rates are excluded. Intervention targeted at these three statistical divisions could reduce much of the variability in mortality in Australia.

An adaptive nonlinear diffusion algorithm for filtering medical images

The nonlinear anisotropic diffusive process has shown the good property of eliminating noise while preserving the accuracy of edges and has been widely used in image processing. However, filtering depends on the threshold of the diffusion process, i.e., the cut-off contrast of edges. The threshold varies from image to image and even from region to region within an image. The problem compounds with intensity distortion and contrast variation. We have developed an adaptive diffusion scheme by applying the Central Limit Theorem to selecting the threshold. Gaussian distribution and Rayleigh distribution are used to estimate the distributions of visual objects in images. Regression under such distributions separates the distribution of the major object from other visual objects in a single-peak histogram. The separation helps to automatically determine the threshold. A fast algorithm is derived for the regression process. The method has been successfully used in filtering various medical images.

Mortality variation across Australia: descriptive data for states and territories, and statistical divisions

OBJECTIVE

To describe variation in all cause and selected cause-specific mortality rates across Australia.

METHODS

Mortality and population data for 1997 were obtained from the Australian Bureau of Statistics. All cause and selected cause-specific mortality rates were calculated and directly standardised to the 1997 Australian population in 5-year age groups. Selected major causes of death included cancer, coronary artery disease, cerebrovascular disease, diabetes, accidents and suicide. Rates are reported by statistical division, and State and Territory.

RESULTS

All cause age-standardised mortality was 6.98 per 1000 in 1997 and this varied 2-fold from a low in the statistical division of Pilbara, Western Australia (5.78, 95% confidence interval 5.06-6.56), to a high in Northern Territory--excluding Darwin (11.30, 10.67-11.98). Similar mortality variation (all p < 0.0001) exists for cancer (1.01-2.23 per 1000) and coronary artery disease (0.99-2.23 per 1000), the two biggest killers. Larger variation (all p < 0.0001) exists for cerebrovascular disease (0.7-11.8 per 10,000), diabetes (0.7-6.9 per 10,000), accidents (1.7-7.2 per 10,000) and suicide (0.6-3.8 per 10,000). Less marked variation was observed when analysed by State and Territory, but Northern Territory consistently has the highest age-standardised mortality rates.

CONCLUSIONS

Analysed by statistical division, substantial mortality gradients exist across Australia, suggesting an inequitable distribution of the determinants of health. Further research is required to better understand this heterogeneity.

[Natural human IgM-antibodies in neuroblastoma therapy: preliminary findings of a phase I/II clinical trial]

BACKGROUND

Sera from healthy individuals contain natural IgM antibodies (anti-NB-Ab) cytotoxic to neuroblastoma (NB) cells. In contrast to healthy children the prevalence of anti-NB-Ab in sera of NB patients is low. Binding of anti-NB-Ab to the NB cell surface leads to activation of complement in vitro. In vivo the injection of the purified IgM fraction from a cytotoxic blood donor results in complete growth arrest of NB xenografts in nude rats. Preliminary results from a phase I/II study to evaluate the pharmacokinetics and side effects of a therapy with anti-NB-Ab are presented here.

PATIENTS

Included in this study are patients with NB stage 4 according to INSS with relapse or non-responders to therapy according to the GPOH-NB-therapy protocol. The patients are negative for anti-NB-Ab and are older than one year.

METHODS

The therapy is based on a complete exchange of the anti-NB-Ab negative patient serum against serum from an anti-NB-Ab positive ABO-compatible donor by means of plasmapheresis.

RESULTS

Up to now, 14 cycles of plasmapheresis have been carried out in 6 NB patients. In 13 of 14 therapy cycles a significant increase in serum toxicity could be observed. Severe side effects have not been seen except a catheter associated thrombosis which was reversible under heparin treatment. After plasmapheresis, pain in the tumor site or regions of metastasis did occur regularly. In some cases temporary elevation of body temperature occurred. One patient had a reduced MIBG uptake after therapy. Tumor necrosis was observed in 2 patients. Three patients showed tumor progress.

CONCLUSION

Immunotherapy of NB in children by serum exchange using anti-NB-Ab positive ABO-compatible donor serum is feasible without major side effects and leads to a significant increase of serum toxicity against NB cells.

Identifying donor concerns to increase live organ donation

Increasing organ donation from live donors is a means to increase the pool of kidneys available for transplantation. To increase the number of live kidney donors, the major concerns of donors must be determined and addressed. This article describes the health and socioeconomic concerns of 61 live kidney donors from the Johns Hopkins Institutions between February 1, 1995 and December 1, 1997. Seventy-five percent of donors reported they had concerns, the most common ones being the effect of donation on their future health, how many work days they would miss, the ability to return to the same activities, and the pain they would experience. Other reported concerns consisted of fear of dying, the risks to a future pregnancy with one kidney, the fear that a son or daughter may need a kidney in the future, and the impact of donation on the family health insurance premium. Interventional strategies including the use of the laparoscopic donor nephrectomy procedure are offered to address these concerns.

[Hepatitis e antibodies in blood donors, hemodialysis patients and in normal people]

A substantial proportion of cases of enterically transmitted acute viral hepatitis occurring in young to middle-aged adults in Asia and the Indian subcontinent is caused by the hepatitis E virus (HEV). It is transmitted mainly by contaminated drinking water and is associated with a high mortality rate (up to 20%) in pregnant women. Chronic forms of hepatitis E are not known. An enzyme immunoassay (EIA) for the detection of IgG antibodies to hepatitis E (Abbott), based on two recombinant HEV antigens, yielded repeatedly reactive results in 5 of 250 (2%) blood donors, 13 of 543 (2.4%) healthy employees from four firms in Hamburg, and in 5 of 150 (3.3%) hemodialysis patients. Supplemental testing by two synthetic peptide EIAs and by Western Blot confirmed positive results in 22/23 samples. None of the samples was IgM antibody-positive. Since no transfusion-transmitted cases of hepatitis E have been observed so far, HEV assays seem to be more useful for differential diagnosis of viral hepatitis than for the screening of donors in the blood bank setting.

[Comparison of leukocyte filters for erythrocyte concentration]

We compared the following leukocyte filter blood systems (BBS): Biotrans Bio R01 Plus, Diamed Sepacell RS-200, Pall BPF4 (log 4 filters) and Biotrans Bio R01 (log 3 filter). We evaluated the leukocyte removal, handling, the increase of free hemoglobin and the loss of red blood cells (RBC) by filtration. A total of 54 buffy-coat-reduced RBCs were suspended in 200 ml PAGGS-M, stored at +4 degrees C for 24 h and filtered subsequently. Samples were taken before storage, immediately before and after filtration to measure total and free Hb and the white blood cell (WBC) contamination.

RESULTS

(1) All log 4 filters showed a comparable reduction of the WBC content per RBC concentrate. (2) Differences were observed in total filtration time and loss of RBCs: Biotrans Bio R01 Plus and Pall BPF4 yielded significantly better results than Diamed Sepacell RS-200. (3) The log 3 filter did not meet the criteria of < 5 x 10(6) WBCs per filtered unit of RBCs (as recommended by the Council of Europe).

Method for segmenting chest CT image data using an anatomical model: preliminary results

We present an automated, knowledge-based method for segmenting chest computed tomography (CT) datasets. Anatomical knowledge including expected volume, shape, relative position, and X-ray attenuation of organs provides feature constraints that guide the segmentation process. Knowledge is represented at a high level using an explicit anatomical model. The model is stored in a frame-based semantic network and anatomical variability is incorporated using fuzzy sets. A blackboard architecture permits the data representation and processing algorithms in the model domain to be independent of those in the image domain. Knowledge-constrained segmentation routines extract contiguous three-dimensional (3-D) sets of voxels, and their feature-space representations are posted on the blackboard. An inference engine uses fuzzy logic to match image to model objects based on the feature constraints. Strict separation of model and image domains allows for systematic extension of the knowledge base. In preliminary experiments, the method has been applied to a small number of thoracic CT datasets. Based on subjective visual assessment by experienced thoracic radiologists, basic anatomic structures such as the lungs, central tracheobronchial tree, chest wall, and mediastinum were successfully segmented. To demonstrate the extensibility of the system, knowledge was added to represent the more complex anatomy of lung lesions in contact with vessels or the chest wall. Visual inspection of these segmented lesions was also favorable. These preliminary results suggest that use of expert knowledge provides an increased level of automation compared with low-level segmentation techniques. Moreover, the knowledge-based approach may better discriminate between structures of similar attenuation and anatomic contiguity. Further validation is required.

Functional advantages of laparoscopic live-donor nephrectomy compared with conventional open-donor nephrectomy

Live-donor kidney transplants accounted for only 27% of all kidney transplants performed in the United States in 1995. Prolonged hospitalization, pain, extended convalescence, and related socioeconomic concerns associated with traditional open-donor nephrectomy surgery may discourage potential donors, contributing to a low percentage of live kidney donors. To remove such disincentives, the laparoscopic live-donor nephrectomy procedure was introduced. In this study, the post-discharge course of 10 laparoscopic nephrectomy donors was compared with that of 27 open nephrectomy donors over the same time period. Laparoscopic nephrectomy donors experienced significantly shorter hospitalizations, less pain, felt able to return to work and normal routines sooner, and needed significantly less assistance during the recuperation period than did open nephrectomy donors. The laparoscopic nephrectomy procedure may decrease many of the concerns of potential donors, thus making live kidney donation more attractive and increasing the kidney supply.

Laparoscopic assisted live donor nephrectomy--a comparison with the open approach

Live donor renal transplantation provides significant advantages when compared with cadaveric donor renal transplantation in terms of improved patient and graft survival, a lower incidence of delayed function, and a shorter waiting time. Yet despite these advantages, live donors continue to be an under utilized source of kidneys for transplantation. Disincentives to live donation include the length of hospitalization, postoperative pain, cosmetic concerns, and the prolonged convalescence associated with the donor operation. In many instances minimally invasive video-assisted techniques have proven more efficacious than standard open procedures in terms of patient discomfort, length of hospital stay, cost, and length of time until the patient can return to full activity. Laparoscopic live donor nephrectomies are being performed at our institution in an attempt to make live donation more attractive to the potential donor. The purpose of this study was to retrospectively review the results of laparoscopic live donor nephrectomy (LapNx) and to compare them with those obtained using the standard open approach (OpenNx). Ten consecutive LapNx were performed from February 1995 through April 1996. The control group consisted of the 20 consecutive OpenNx performed at the same institution from January 1991 through January 1995 immediately before the initiation of the LapNx program. Live donors were considered candidates for LapNx if they possessed at least one kidney with normal renal anatomy with single renal vessels and a single ureter. LapNx was safely performed in all cases. No patients required open conversion or blood transfusions. The allograft warm ischemic time for the laparoscopic cases was 4.2+/-1.3 min. All kidneys harvested laparoscopically produced urine on the table immediately upon revascularization. Presently nine of the ten recipients have functioning allografts. At three months posttransplant the calculated recipient creatinine clearances were 67.0+/-11.5 ml/min and 64.8+/-21.4 ml/min for the LapNx and OpenNx groups, respectively (P=NS). The LapNx donors had a significantly decreased estimated blood loss, shorter time until resumption of oral intake, decreased postoperative pain (in terms of decreased analgesic requirements), shorter hospitalization, and a shorter interval until the resumption of full activities (P<0.05 for all). In addition, the LapNx group donors returned to work sooner than the OpenNx group (3.9+/-1.6 wk vs. 6.4+/-3.1 wk, respectively) (P=0.024). Four individuals agreed to donate a kidney only after learning of the availability of the laparoscopic approach. We conclude that laparoscopic live donor nephrectomy is technically feasible. In addition, it may offer significant advantages over the standard open approach in terms of patient comfort and convenience. These advantages may make live donor renal transplantation more attractive to prospective donors. The potential decrease in hospitalization and convalescence may also prove to be financially advantageous. We believe that further careful study of this procedure is warranted.

[Mobile blood gas and laboratory monitoring. A new technology in clinical routine]

INTRODUCTION

Decision-making on therapy in acute cases involves clinical examination and monitoring of vital parameters and fluid balance; especially, however, laboratory parameters. The present study compared the results of a new bedside laboratory analysis system (PortLab, i-STAT Corp., Princeton NJ) with the analytical results obtained in our central laboratory. In a second phase personnel costs and turnover times of the two methods were evaluated comparatively.

MATERIALS AND METHODS

The PortLab system consists of a basic unit (539 g) with an integrated display and disposable silicon cartridges with thin-film electrodes. Up to 8 parameters can be determined simultaneously in 60 microliters of whole blood. Fifty results obtained with the PortLab system of the parameters sodium, potassium, chlorid, glucose, BUN, hematocrit, the calculated haemoglobin and blood gas analysis were correlated with the results obtained by central laboratory analysis. In a second phase, all procedural steps, the time needed and the turnover times for laboratory analysis were compared with the expenditure for the same analyses performed with the PortLab system.

RESULTS AND DISCUSSION

The results obtained using PortLab analysis correlated very well with those of the central laboratory (between 0.966 for the hematocrit and 0.994 for pO2). Three steps were required to perform bedside analysis with the PortLap system. The staff was occupied for 1 min. and 15 sec. and the results were ready within 4 min. and 45 sec. (pure analysis time < 2 min.). Analysis in the central laboratory required 8 steps, the intensive care staff was occupied for 6 min. and 15 sec., 5 min. and 15 sec. of which they were away from the patients' side. Analysis of blood gases required 4 steps, the result was ready in 4 min. 15 sec. The personnel was occupied for an equally long time. The use of PortLab saved personnel resources of 5 minutes per laboratory analysis and 3 minutes per blood gas analysis.

CONCLUSION

The PortLab system proved easy to handle and reliable. Valuable personnel resources can be saved. This method cannot replace conventional laboratory analyses, but enables more extensive monitoring of patients and their laboratory parameters. The industry should develop analogous monitoring systems for modular solutions.

Thyrotropin-releasing hormone: does two hundred micrograms provide effective stimulation to the preterm fetal pituitary gland compared with four hundred micrograms?

OBJECTIVE

Our purpose was to compare the response of the fetal pituitary-thyroid axis to 200 and 400 micrograms of thyrotropin-releasing hormone administered to the mother immediately before delivery with a control group.

STUDY DESIGN

A randomized controlled trial was conducted of 26 women at gestational ages between 24 weeks and 33 weeks 6 days who had received one or more doses of betamethasone who were expected to be delivered within 1 to 4 hours. Women received either 200 or 400 micrograms of thyrotropin-releasing hormone or were in the control group.

RESULTS

Thyroid-stimulating hormone determinations on cord blood had a higher mean level in both treatment groups compared with the control group. No differences were seen in cord blood results between the two treatment groups for thyroid-stimulating hormone, thyroxine, triiodothyronine, free thyroxine, free triiodothyronine, and prolactin levels. The only other differences found were in a higher level in total thyroxine and a lower level of free thyroxine in the 400 micrograms thyrotropin-releasing hormone group compared with the 200 micrograms group in the 48-hour blood determinations.

CONCLUSION

Both 200 and 400 micrograms of thyrotropin-releasing hormone provided fetal pituitary stimulation, as reflected in fetal thyroid-stimulating hormone levels in cord blood, and both gave significantly higher levels compared with a control group.

Routine stresses in caring for a child with cystic fibrosis

Difficulties experienced by mothers caring for a child with cystic fibrosis were assessed. Difficulties were categorized as: (1) developmental, which included tasks generic to all families (bedtimes, socialization, siblings and communication with others); and (2) illness, which were especially pertinent to the care of the child with cystic fibrosis (mealtimes, physiotherapy and home-based medical care). Age differences were found in stresses associated with developmental routines, with mothers of younger children reporting more difficulties. With regard to illness routines, more difficulties were reported for children in better health (higher Shwachman scores). The data suggest that parents experience increasing difficulties in implementing home-based medical care where the child is in better health. Clinic staff need to be more aware of these difficulties and target information to parents appropriately.

Screening for colorectal cancer: what are the costs?

We examined a screening program for colorectal cancer in South Australia in terms of its overall direct costs to society and costs to participants. The best estimate of the cost per cancer detected was $18,924 (Australian dollars). Potential improvements in health outcome through screening are discussed in light of these costs.

PALS (pregnancy and lifestyle study): association between occupational and environmental exposure to chemicals and reproductive outcome

A prospective study examined the reproductive outcome, live birth, miscarriage or 9 months infertility, in 585 participating couples. Examination of the data relating to environmental and occupational exposure to chemicals and radiation revealed the following associations. Infertility was significantly associated with male factors of age, occupational exposure to dusts and occupation of labourer in men aged 35 or older. Female factors associated with infertility were age and home renovating if aged 35 or older. First trimester spontaneous miscarriage was associated with male factors of age, X-rays of the abdomen or back, occupation as a tradesperson, home exposure to glues, oil paints or oven cleaners. Female factors included age, visiting factories in the course of work, X-rays of the abdomen, home use of glues and working at home if aged less than 35. The most significant findings of the study are the poor outcomes associated with abdominal/back X-rays and home exposure to chemicals. The possible effects of having different numbers of positive factors was examined for each of miscarriage and 9 months infertility. Nine factors were examined for miscarriage and couples were found to have from zero to seven of these. The observed rate of pregnancy loss ranged from 3.7% to 75% with increasing numbers of factors. For infertility, four factors were examined and couples were found to have from zero to four of these. The observed rate of 'infertility' ranged from 8.4% to 33.3% with increasing numbers of factors. The statistical significance of both sets of results is p = < 0.0001. The effects of these exposures on outcome is thus cumulative.

Screening for colorectal cancer using an immunochemical test for faecal occult blood: results of the first 2 years of a South Australian programme

This paper reports an evaluation of the first 2 years of a South Australian screening programme for colorectal cancer which was established in 1988 by the Institute of Medical and Veterinary Science. The programme uses an immunochemical test for faecal occult blood. Based on 1 year of follow-up, over the period of this analysis there were 24 cancers and 99 adenomas detected in 6208 participants, and the estimated sensitivity and specificity of the test (for colorectal cancer) were 82.8 and 95.9%, respectively. In many cases the test was used to detect recurrence of disease in individuals with a previous diagnosis of colorectal cancer. The estimated predictive value of a positive test for colorectal cancer in this population was 7.5%. Results suggest that participants belonged to higher-than-average socio-economic groups and were more likely than the general population to have a family history of colorectal cancer. Almost one-third had suffered from bowel symptoms in the 6 months before taking the test. These unique characteristics of participants, which limit the generalizability of results to the wider population, may result from the programme's reliance on self-recruitment methods. Consistent evidence for improvements in mortality in populations screened for colorectal cancer is still required before a recommendation for widespread screening in Australia can be made.

The epidemiology of blindness and trachoma in the Anangu Pitjantjatjara of South Australia

OBJECTIVE

To determine the prevalence of trachoma and blindness in the Aboriginal population in the Anangu Pitjantjatjara and Yalata lands of South Australia.

DESIGN AND SETTING

A population-based prevalence survey undertaken in conjunction with routine South Australian Aboriginal Trachoma and Eye Health Program trips during 1989 and 1990.

RESULTS

A group of 1514 individuals aged 0-90 years, or approximately 58% of the estimated Aboriginal population in the Anangu Pitjantjatjara and Yalata lands, was examined. Active inflammatory trachoma was found in 17.6% of the group (266 individuals), cicatricial trachoma in 25.2% (382) and binocular blindness (Australian definition) in 1.5% (22). The major causes of monocular and binocular blindness were trachoma, cataracts and trauma. Two per cent of women (17 of 849) were blind, compared with 0.8% (5 of 665) of men (odds ratio, 3.22; 95% confidence interval, 1.03-10.43).

CONCLUSIONS

Although trachoma is still endemic in the "traditional" Aboriginal population of SA, its prevalence and severity appear to be less than previously recorded. However, the prevalence of blindness is comparable with that found in developing countries and the causes are still largely preventable. Further effort is required to reduce trachoma and preventable or treatable blindness in these communities.

Screening for colorectal cancer. Knowledge, attitudes and practices of South Australian GPs

OBJECTIVE

To examine knowledge, attitudes and practices of South Australian general practitioners (GPs) in relation to screening for colorectal cancer.

DESIGN

A descriptive study in which data were collected by means of postal questionnaires.

MAIN OUTCOME MEASURES

Use of screening tests for colorectal cancer, knowledge in relation to colorectal cancer prevention, opinions on organisation and delivery of colorectal cancer screening.

RESULTS

The response rate to the survey was 66.3%. GPs showed considerable variability in screening practices, particularly for individuals who are at no increased risk of colorectal cancer. Mass screening with the faecal occult blood test (FOBT), particularly if it is centrally coordinated, was not widely endorsed, in contrast with strategies which provide a central role for the GP. On the whole, GPs preferred patient-initiated, rather than doctor-initiated, screening. We found a number of knowledge deficits in relation to FOBT screening; many GPs felt they had inadequate training in this area.

CONCLUSION

Clear and consistent guidelines for colorectal cancer screening are required. Medical education about colorectal cancer should also be addressed.

The research and development agenda for cancer prevention and education in Australia

In Australia the most important preventable causes of cancer, in order of importance, are tobacco smoking, diet, obesity, sunlight exposure, alcohol consumption and occupational exposure to carcinogens. We review and discuss these causes and their potential preventability and discuss three broad strategies in cancer prevention: public health policy and legislation, screening, and education and behavior change. In each of these broad areas, current research evidence and relevant approaches to research and development are considered. Six areas of research and development priority for cancer prevention and education are suggested: cigarette smoking (particularly among children and adolescents); protection of the skin from exposure to strong sunlight; screening; dietary choices; occupational exposures; and the social and environmental context of cancer prevention. All of these strategies and concerns will not apply to every country in the Asia-Pacific region but may be useful as guidelines and as a stimulus for determining particular local priorities.

Prospective, controlled study of a polyvalent pseudomonas vaccine in cystic fibrosis--three year results

Thirty four children with cystic fibrosis allocated to pseudomonas vaccine and control groups were studied for three years. No significant differences were observed in the numbers colonised by Pseudomonas aeruginosa or in the overall disease progress of the two groups.