The formal specification of abstract data types and their implementation in Fortran 90: Implementation issues concerning the use of pointers

In this paper we continue our investigation into the development of computational-science software based on the identification and formal specification of Abstract Data Types (ADTs) and their implementation in Fortran 90. In particular, we consider the consequences of using pointers when implementing a formally specified ADT in Fortran 90. Our aim is to highlight the resulting conflict between the goal of information hiding, which is central to the ADT methodology, and the space efficiency of the implementation. We show that the issue of storage recovery cannot be avoided by the ADT user, and present a range of implementations of a simple ADT to illustrate various approaches towards satisfactory storage management. Finally, we propose a set of guidelines for implementing ADTs using pointers in Fortran 90. These guidelines offer a way gracefully to provide disposal operations in Fortran 90. Such an approach is desirable since Fortran 90 does not provide automatic garbage collection which is offered by many object-oriented languages including Eiffel, Java, Smalltalk, and Simula.

Artificial receptors for the extraction of nucleoside metabolite 7-methylguanosine from aqueous media made by molecular imprinting

A series of imprinted polymers targeting nucleoside metabolites, prepared using a template analogue approach, are presented. These were prepared following selection of the optimum functional monomer by solution association studies using 1H-NMR titrations whereby methacrylic acid was shown to be the strongest receptor with and affinity constant of 621 ± 51 L mol-1 vs. 110 ± 16 L mol-1 for acrylamide. The best performing polymers were prepared using methanol as porogenic co-solvent and although average binding site affinities were marginally reduced, 2.3×104 L mol-1 vs. 2.7×104 L mol-1 measured for a polymer prepared in acetonitrile, these polymers contained the highest number of binding sites, 5.27 μmol g-1¬¬ vs. 1.64 μmol g-1, while they also exhibited enhanced selectivity for methylated guanosine derivatives. When applied as sorbents in the extraction of nucleoside derivative cancer biomarkers from synthetic urine samples, significant sample clean-up and recoveries of up to 90% for 7-methylguanosine were achieved.

Nonconservative dynamics in long atomic wires

The effect of nonconservative current-induced forces on the ions in a defect-free metallic nanowire is investigated using both steady-state calculations and dynamical simulations. Nonconservative forces were found to have a major influence on the ion dynamics in these systems, but their role in increasing the kinetic energy of the ions decreases with increasing system length. The results illustrate the importance of nonconservative effects in short nanowires and the scaling of these effects with system size. The dependence on bias and ion mass can be understood with the help of a simple pen and paper model. This material highlights the benefit of simple preliminary steady-state calculations in anticipating aspects of brute-force dynamical simulations, and provides rule of thumb criteria for the design of stable quantum wires.

The Use of ART in Elderly Patients after 2 years

Caries experience is high in the elderly, and barriers to care for older adults include fear and cost. Access to care is especially problematic in the case of frail and homebound elderly. Objective: to compare the survival of restorations placed using Atraumatic Restorative Treatment (ART) and a conventional technique using rotary instruments and a resin-modified glass-ionomer (CT) to treat carious lesions in older patients. Methods: In this randomised clinical trial, 99 independently living adults (65-90 yrs) with carious lesions were recruited from a geriatric day hospital and a community centre and randomly allocated to receive either ART or conventional restorations. They received tailored oral hygiene instructions and scaling and polishing of teeth prior to restoration placement. The survival of restorations was assessed 6, 12 and 24 months after restoration placement by an independent examiner. Results: Ninety-nine patients participated in the trial, 46 males and 53 females, with a mean age of 73.2 (SD: 6.8). In total, 300 restorations were placed, 142 ART in 51 patients and 158 conventional restorations in 48 patients, with an average of 2.8 ART (SD: 1.83) and 3.2 conventional (SD: 2.62) restorations placed per patient. After 2 years, 88 ART and 117 conventional restorations were assessed. The restoration survival percentages were 93.1% and 94%, respectively. Conclusion: ART was found to be as effective as a conventional restorative approach to treat older adults after 2 years and could be a useful tool to provide dental care for older dentate adults.

Recipient obesity and outcomes after kidney transplantation: a systematic review and meta-analysis

BACKGROUND: The prevalence of obesity is increasing globally and is associated with chronic kidney disease and premature mortality. However, the impact of recipient obesity on kidney transplant outcomes remains unclear. This study aimed to investigate the association between recipient obesity and mortality, death-censored graft loss and delayed graft function (DGF) following kidney transplantation.

METHODS: A systematic review and meta-analysis was conducted using Medline, Embase and the Cochrane Library. Observational studies or randomized controlled trials investigating the association between recipient obesity at transplantation and mortality, death-censored graft loss and DGF were included. Obesity was defined as a body mass index (BMI) of ≥30 kg/m(2). Obese recipients were compared with those with a normal BMI (18.5-24.9 kg/m(2)). Pooled estimates of hazard ratios (HRs) for patient mortality or death-censored graft loss and odds ratios (ORs) for DGF were calculated.

RESULTS: Seventeen studies including 138 081 patients were analysed. After adjustment, there was no significant difference in mortality risk in obese recipients [HR = 1.24, 95% confidence interval (CI) = 0.90-1.70, studies = 5, n = 83 416]. However, obesity was associated with an increased risk of death-censored graft loss (HR = 1.06, 95% CI = 1.01-1.12, studies = 5, n = 83 416) and an increased likelihood of DGF (OR = 1.68, 95% CI = 1.39-2.03, studies = 4, n = 28 847).

CONCLUSIONS: Despite having a much higher likelihood of DGF, obese transplant recipients have only a slightly increased risk of graft loss and experience similar survival to recipients with normal BMI.

Suspension plasma sprayed coatings using dilute hydrothermally produced titania feedstocks for photocatalytic applications

Titanium dioxide coatings have potential applications including photocatalysts for solar assisted hydrogen production, solar water disinfection and self-cleaning windows. Herein, we report the use of suspension plasma spraying (SPS) for the deposition of conformal titanium dioxide coatings. The process utilises a nanoparticle slurry of TiO2 (ca. 6 and 12 nm respectively) in water, which is fed into a high temperature plasma jet (ca. 7000-20 000 K). This facilitated the deposition of adherent coatings of nanostructured titanium dioxide with predominantly anatase crystal structure. In this study, suspensions of nano-titanium dioxide, made via continuous hydrothermal flow synthesis (CHFS), were used directly as a feedstock for the SPS process. Coatings were produced by varying the feedstock crystallite size, spray distance and plasma conditions. The coatings produced exhibited ca. 90-100% anatase phase content with the remainder being rutile (demonstrated by XRD). Phase distribution was homogenous throughout the coatings as determined by micro-Raman spectroscopy. The coatings had a granular surface, with a high specific surface area and consisted of densely packed agglomerates interspersed with some melted material. All of the coatings were shown to be photoactive by means of a sacrificial hydrogen evolution test under UV radiation and compared favourably with reported values for CVD coatings and compressed discs of P25.

Socioeconomic inequalities in attitudes towards cancer: An international cancer benchmarking partnership study

Socioeconomic status (SES) differences in attitudes towards cancer have been implicated in the differential screening uptake and the timeliness of symptomatic presentation. However, the predominant emphasis of this work has been on cancer fatalism, and many studies focus on specific community subgroups. This study aimed to assess SES differences in positive and negative attitudes towards cancer in UK adults. A population-based sample of UK adults (n=6965, age≥50 years) completed the Awareness and Beliefs about Cancer scale, including six belief items: three positively framed (e.g. 'Cancer can often be cured') and three negatively framed (e.g. 'A cancer diagnosis is a death sentence'). SES was indexed by education. Analyses controlled for sex, ethnicity, marital status, age, self-rated health, and cancer experience. There were few education-level differences for the positive statements, and overall agreement was high (all>90%). In contrast, there were strong differences for negative statements (all Ps<0.001). Among respondents with lower education levels, 57% agreed that 'treatment is worse than cancer', 27% that cancer is 'a death sentence' and 16% 'would not want to know if I have cancer'. Among those with university education, the respective proportions were 34, 17 and 6%. Differences were not explained by cancer experience or health status. In conclusion, positive statements about cancer outcomes attract near-universal agreement. However, this optimistic perspective coexists alongside widespread fears about survival and treatment, especially among less-educated groups. Health education campaigns targeting socioeconomically disadvantaged groups might benefit from a focus on reducing negative attitudes, which is not necessarily achieved by promoting positive attitudes.

Immunological determination of the pharmaceutical diclofenac in environmental and biological samples

A highly sensitive and specific competitive ELISA on 96-microwell plates was developed for the analysis of the nonsteroidal anti-inflammatory drug diclofenac. Within the water cycle in Europe, this is one of the most frequently detected pharmaceutically active compounds. The LOD at a signal-tonoise ratio (S/N) of 3, and the IC ₅₀, were found to be 6 ng/L and 60 ng/L respectively in tap water. In a comparative study using ELISA and GC-MS, diclofenac levels in wastewater from 21 sewage treatment plants were determined and a good correlation between these methods was found (ELISA vs. GCMS: r = 0.70, slope = 0,90, intercept = 0.37, n = 24). An average degradation rate of -25% can be calculated. Labscale-experiments on the elimination of diclofenac in continuous pilot sewage plants revealed a removal rate of only 5% over a period of 13 weeks. In a further study, the ELISA was applied to a number of extracts of various animal tissues from a range of species, and again a very good relationship between ELISA and LC-ESI/MS data sets was obtained (r = 0.90, p<0.0001; n = 117). The ELISA has proven to be a simple, rapid, reliable and affordable alternative to otherwise costly and advanced techniques for the detection of diclofenac in matrix diverse water samples and tissue extracts after only relatively simple sample preparation. © 2007 American Chemical Society.

Carbon distribution within the plant and rhizosphere in laboratory and field-grown Lolium perenne at different stages of development

Carbon distribution within perennial ryegrass was determined at different stages of plant development, by pulse-labelling laboratory and field-grown plants with ¹⁴C-CO₂. During the early stages of growth (23-51 days), C distribution of laboratory grown plants was not markedly affected by plant age, with 12.4-24% of net assimilated label lost into the soil as root-soil respiration. The percentage of net assimilate translocated below ground was 20-28% during this stage of growth. At 65 days, the percentage of the label translocated below ground decreased to 8.1% of the net assimilate, with a subsequent decrease in root-soil respiration to 3.9%. The ability of the plant to fix the label (expressed in MBq g^-1 oven dry total plant weight) decreased steadily as the plants aged. When the 30 day old plants were subjected to water stress (soil water potential -1.5 MPa) for 2 days before pulse-labelling, root-soil respiration of the pulse-label decreased compared with plants grown at field capacity. The distribution of a ¹⁴C pulse-label within perennial ryegrass grown under field conditions was found to be dependent on the age of the plants. For 4 week old plants, 67% of net assimilated label was translocated below ground, with 64.8% of this respired by the roots and soil. Less label was translocated below ground at subsequent pulse-labels from weeks 8 to 24. The proportion of label translocated below ground respired by the roots and soil also decreased. The investment of label in the plant shoots was found to be greater in field grown plants as compared to plants of the same age grown in a controlled, laboratory environment. © 1990.

Efficacy and safety of ivacaftor in patients with cystic fibrosis who have an Arg117His-CFTR mutation: a double-blind, randomised controlled trial

BACKGROUND: Ivacaftor has been previously assessed in patients with cystic fibrosis with Gly551Asp-CFTR or other gating mutations. We assessed ivacaftor in patients with Arg117His-CFTR, a residual function mutation.

METHODS: We did a 24-week, placebo-controlled, double-blind, randomised clinical trial, which enrolled 69 patients with cystic fibrosis aged 6 years and older with Arg117His-CFTR and percentage of predicted forced expiratory volume in 1 s (% predicted FEV1) of at least 40. We randomly assigned eligible patients (1:1) to receive placebo or ivacaftor 150 mg every 12 h for 24 weeks. Randomisation was stratified by age (6-11, 12-17, and ≥18 years) and % predicted FEV1 (<70, ≥70 to ≤90, and >90). The primary outcome was the absolute change from baseline in % predicted FEV1 through week 24. Secondary outcomes included safety and changes in sweat chloride concentrations and Cystic Fibrosis Questionnaire-Revised (CFQ-R) respiratory domain scores. An open-label extension enrolled 65 of the patients after washout; after 12 weeks, we did an interim analysis.

FINDINGS: After 24 weeks, the treatment difference in mean absolute change in % predicted FEV1 between ivacaftor (n=34) and placebo (n=35) was 2·1 percentage points (95% CI -1·13 to 5·35; p=0·20). Ivacaftor treatment resulted in significant treatment differences in sweat chloride (-24·0 mmol/L, 95% CI -28·01 to -19·93; p<0·0001) and CFQ-R respiratory domain (8·4, 2·17 to 14·61; p=0·009). In prespecified subgroup analyses, % predicted FEV1 significantly improved with ivacaftor in patients aged 18 years or older (treatment difference vs placebo: 5·0 percentage points, 95% CI 1·15 to 8·78; p=0·01), but not in patients aged 6-11 years (-6·3 percentage points, -11·96 to -0·71; p=0·03). In the extension study, both placebo-to-ivacaftor and ivacaftor-to-ivacaftor groups showed % predicted FEV1 improvement (absolute change from post-washout baseline at week 12: placebo-to-ivacaftor, 5·0 percentage points [p=0·0005]; ivacaftor-to-ivacaftor, 6·0 percentage points [p=0·006]). We did not identify any new safety concerns. The studies are registered with ClinicalTrials.gov (the randomised, placebo-controlled study, number NCT01614457; the open-label extension study, number NCT01707290).

INTERPRETATION: Although this study did not show a significant improvement in % predicted FEV1, ivacaftor did significantly improve sweat chloride and CFQ-R respiratory domain scores and lung function in adult patients with Arg117His-CFTR, indicating that ivacaftor might benefit patients with Arg117His-CFTR who have established disease.