Transient distributions of composition and temperature in a gas-solid packed bed reactor by near-infrared tomography

Near-infrared diffuse tomography was used in order to observe dynamic behaviour of flowing gases by measuring the 3D distributions of composition and temperature in a weakly scattering packed bed reactor, subject to wall effects and non-isothermal conditions. The technique was applied to the vapour phase hydrogen isotopic exchange reaction in a hydrophobic packing of low aspect ratio made of platinum on styrene divinyl benzene sulphonate copolymer resin. The results of tomography revealed uneven temperature and composition maps of water and deuterated water vapours in the core-packed bed and in the vicinity of the wall owing to flow maldistribution. The dynamic lag between the near-wall water vapour and deuterated water vapour compositions were observed suggesting that the convective transfer which was significant near the wall at the start, owing to high porosity, was also effective at large conversions. (C) 2012 Elsevier B.V. All rights reserved.

Can Certain Genotypes Predispose to Poor Asthma Control in Children? A Pharmacogenetic Study of 9 Candiate Genes in Children with Difficult Asthma

Objective: We tested the hypothesis that patients with difficult asthma have an increased frequency of certain genotypes that predispose them to asthma exacerbations and poor asthma control.

Methods: A total of 180 Caucasian children with confirmed asthma diagnosis were selected from two phenotypic groups; difficult (n = 112) versus mild/moderate asthma (n = 68) groups. All patients were screened for 19 polymorphisms in 9 candidate genes to evaluate their association with difficult asthma.

Key Results: The results indicated that LTA4H A-9188.G, TNFa G-308.A and IL-4Ra A1727.G polymorphisms were significantly associated with the development of difficult asthma in paediatric patients (p,0.001, p = 0.019 and p = 0.037, respectively). Haplotype analysis also revealed two haplotypes (ATA haplotype of IL-4Ra A1199.C, IL-4Ra T1570.C and IL- 4Ra A1727.G and CA haplotype of TNFa C-863.A and TNFa G-308.A polymorphisms) which were significantly associated with difficult asthma in children (p = 0.04 and p = 0.018, respectively).

Conclusions and Clinical Relevance: The study revealed multiple SNPs and haplotypes in LTA4H, TNFa and IL4-Ra genes which constitute risk factors for the development of difficult asthma in children. Of particular interest is the LTA4H A- 9188.G polymorphism which has been reported, for the first time, to have strong association with severe asthma in children. Our results suggest that screening for patients with this genetic marker could help characterise the heterogeneity of responses to leukotriene-modifying medications and, hence, facilitate targeting these therapies to the subset of patients who are most likely to gain benefit. ©2013 Almomani et al.

Field observation of sequestration of uranium in iron-rich sediments under sequential reduction-oxidation conditions at the DOE Oak Ridge IFRC

At the U.S. DOE Oak Ridge Integrated Field Research Challenge (ORIFRC) site, the iron content of shallow subsurface materials (i.e. weathered saprolite) is relatively high (up to 5-6% as w/w), and therefore, the forms of the iron species present plays a critical role in the long-term sequestration of uranium. A long term pilot-scale study of the bioreduction and reoxidation of uranium conducted at the ORIFRC area 3 site, adjacent to the former S-3 disposal ponds (source zone), has provided us with the opportunity to study the impact of iron species on the sequestration of U(VI). The aqueous U(VI) concentrations at the site were decreased to below the EPA MCL through the intermittent injection of ethanol as the electron donor. Previous field tests indicated that both oxygen and nitrate could oxidize the bioreduced U(IV) and cause a short-term rebound of aqueous phase uranium concentration after the oxidative agents were delivered directly to the bioreduced zone.

A field test has been conducted to examine the long-term effect of exposure of bioreduced sediments to nitrate in contaminated groundwater for more than 1,380 days at the Area 3 site. Contaminated groundwater was allowed to invade the previously bioreduced zone via the natural groundwater gradient after an extended period in which reducing conditions were maintained and the bioreduced zone was protected from the influx of upgradient contaminated groundwater. The geochemical response to the invasion of contaminated groundwater was dependent on whether the monitoring location is in the middle or the fringe of the previously bioreduced zone. In general, the nitrate concentrations in the previously bioreduced area, increased gradually from near zero to ~50-300 mM within 200 days and then stabilized. The pH declined from bioreduced levels of 6.2-6.7 to below 5.0. Uranium concentrations rebounded in all monitoring wells but at different rates. At most locations U concentrations rebounded, declined and then rebounded again. Methane gas disappeared while a significant level (20,000 to 44,000 ppmv) N2O was found in the groundwater of monitoring wells after three years of reoxidization.

The U(IV) in sediments was mainly reoxidized to U(VI) species. Based on XANES analysis, the predominate uranium in all samples after re-oxidation was similar to a uranyl nitrate form. But the U content in the sediment remained as high as that determined after bioreduction activates were completed, indicating that much of the U is still sequestrated in situ. SEM observations of surged fine sediments revealed that clusters of colloidal-sized (200-500nm) U-containing precipitates appeared to have formed in situ, regardless from sample of FW106 in non-bioactivity control area or of pre-bioreduced FW101-2 and FW102-3. Additionally, SEM-EDS and microprobe analysis, showed that the U-containing precipitates (~1% U) in FW106 are notably higher in Fe, compared to the precipitates (~1-2.5% U) from FW101-2 and FW102-3. However, XRF analysis indicated that the U content was remained as high as 2180 and 1810 mg/kg with U/Fe ratio at 0.077 and 0.055 vs 0.037 g/g, respectively in pre-bioreduced FW101-2 and FW102-3, suggesting more U sequestrated by Fe in pre-bioreduced sediments.

Efficacy and safety of adjunctive mitomycin C during Ahmed Glaucoma Valve implantation:A prospective randomized clinical trial

Purpose To evaluate the efficacy and safety of intraoperative mitomycin C (MMC) in eyes undergoing Ahmed Glaucoma Valve implantation. Design Randomized controlled clinical trial. Participants Sixty patients with refractory glaucoma. Intervention Sixty eyes of 60 patients with refractory glaucoma were randomized to receive intraoperative MMC (0.5 mg/ml for 5 minutes) (n = 34) or balanced salt solution (n = 26) during Ahmed Glaucoma Valve implantation. Main outcome measures Surgical success was defined according to 2 different criteria: (1) postoperative intraocular pressure (IOP) between 6 and 21 mmHg, with or without antiglaucoma medications, and (2) IOP reduction of at least 30% relative to preoperative values. Eyes requiring additional glaucoma surgery, developing phthisis, or showing loss of light perception were classified as failures. Success rates in both groups were compared using Kaplan-Meier survival curves and the log rank test. Other outcome measures were mean IOP, number of glaucoma medications, and complications. Results After a mean follow-up of 12.3 months, Kaplan-Meier survival analysis showed a probability of success of 59% at 18 months for the MMC group and 61% for the control group when the first criterion for success was used (IOP between 6 and 21 mmHg). When an IOP reduction of at least 30% was used as the criterion to define success, the Kaplan-Meier survival analysis demonstrated a probability of success at 18 months of 62% for the MMC group and 67% for the control group. There were no significant differences in survival rates between the 2 groups with either criterion (P = 0.75 and P = 0.37, respectively). After 15 days postoperatively, the mean IOP did not significantly differ for both MMC and control eyes. Mean numbers of postoperative antiglaucoma medications were similar in MMC-treated eyes and controls. There was no significant difference between the incidences of postoperative complications in both groups. Conclusion Mitomycin C did not increase the short- or intermediate-term success rates of Ahmed Glaucoma Valve implantation. © 2004 by the American Academy of Ophthalmology.

Fasciola hepatica: A light and electron microscope study of sustentacular tissue and heterophagy in the testis

In order to investigate cytolytic activity in the testis of Fasciola hepatica, flukes belonging to several different triclabendazole (TCBZ)-sensitive and TCBZ-resistant isolates, and wildtype flukes from field infections, were studied by light and electron microscopy with a view to identifying sites of heterophagy and macromolecular hydrolysis. At the periphery of the testis tubules in all the flukes examined, large euchromatic nuclei, each bearing a prominent nucleolus, were seen. These were invested with a thin cytoplasmic layer, extensions of which partially enveloped and probably supported the neighbouring spermatogonia. No lateral cell boundaries were identified in this tissue, possibly indicating syncytial organisation. The tissue, considered to be analogous to Sertoli cells in vertebrate testis, was identified as sustentacular tissue. It displayed cytoplasmic features consistent with protein/glycoprotein synthesis (through a granular endoplasmic reticulum-Golgi mediated mechanism) and intracellular digestion/heterophagy (through a lysosomal system). The intracytoplasmic hydrolytic activity of the sustentacular tissue probably serves to scavenge effete cells and cytoplasmic debris, to recycle useful molecules, to promote spermatozoon maturation and possibly to aid osmoregulation within the tubules. Certain protein-containing macromolecules synthesised in the sustentacular tissue may contribute to the seminiferous fluid, or have pheromonal activity. The presence of numerous mitochondria and abundant smooth endoplasmic reticulum is consistent with facilitation of inward and outward movement of micromolecular nutrients, metabolites including excretory products and water. In the sustentacular tissue of certain flukes with dysfunctional spermiogenesis, there was increased heterophagic and cytolytic scavenging activity. The cytoplasmic residual vacuoles remaining after the release of spermatids were also identified as possible sites for lysosome-mediated intracellular digestion and osmoregulation in the testis tubules of F. hepatica. (C) 2012 Elsevier B.V. All rights reserved.

PtRuO/Ti anodes with a varying Pt:Ru ratio for direct methanol fuel cells

PtRuO/Ti anodes with a varying Pt:Ru ratio were prepared by thermal deposition of a PtRuO catalyst layer onto a Ti mesh for the direct methanol fuel cell (DMFC). The morphology and structure of the catalyst layers were analyzed by SEM, EDX, and XRD. The catalyst coating layers became porous with increase of the Ru content, and showed oxide and alloy characteristics. The relative activities of the PtRuO/Ti electrodes were assessed and compared using half-cell tests and single DMFC experiments. The results showed that these electrodes were very active for the methanol oxidation and that the optimum Ru surface coverage was ca. 38% for a DMFC operating at 20-60 °C. © 2006 Elsevier B.V. All rights reserved.

SPR immunosensor for the detection of okadaic acid in mussels using magnetic particles as antibody carriers

Protein G-coated magnetic particles (MPs) were used as immobilisation supports for an antibody against okadaic acid (MAb(OA)) and carriers into a surface plasmon resonance (SPR) device for the development of a direct competitive immunosensor for okadaic acid (OA). SPR analysis of MAb(OA)-MP conjugates demonstrated that conjugations were successful with complete immobilisation of all the antibody biomolecules onto the MPs. Moreover, MAb(OA)-MP conjugates provided up to 11-fold higher SPR signals, compared to free MAb(OA). The use of conjugates in the direct competition assay provided a 3-fold lower LOD mu g/L (2.6 mu g of OA/L, equivalent to 12 mu g of OA/kg mussel meat). The presence of mussel matrix did not interfere in the OA quantification as seen in the calibration curves. Mussel samples, obtained from Ebro Delta's bays (NW Mediterranean) during a diarrheic shellfish poisoning (DSP) event and in the presence of Dinophysis sacculus, an OA producer, in the shellfish production area, were analysed with the MP-based SPR immunosensor. The OA contents correlated with those obtained by liquid chromatography-tandem mass spectrometry (LC-MS/MS) (y = 0.984x -5.273, R-2 = 0.789, p <0.001) and by mouse bioassay (MBA).

Impact of offshore wind power forecast error in a carbon constraint electricity market

This paper investigates the impacts of offshore wind power forecast error on the operation and management of a pool-based electricity market in 2050. The impact from offshore wind power forecast errors of up to 2000 MW on system generation costs, emission costs, dispatch-down of wind, number of start-ups and system marginal price are analysed. The main findings of this research are an increase in system marginal prices of approximately 1% for every percentage point rise in the offshore wind power forecast error regardless of the average forecast error sign. If offshore wind power generates less than forecasted (−13%) generation costs and system marginal prices increases by 10%. However, if offshore wind power generates more than forecasted (4%) the generation costs decrease yet the system marginal prices increase by 3%. The dispatch down of large quantities of wind power highlights the need for flexible interconnector capacity. From a system operator's perspective it is more beneficial when scheduling wind ahead of the trading period to forecast less wind than will be generated.

First comprehensive peat depositional records for tin, lead and copper associated with the antiquity of Europe's largest cassiterite deposits

Tin, as a constituent of bronze, was central to the technological development of early societies, but cassiterite (SnO2) deposits were scarce and located distantly from the centres of Mediterranean civilizations. As Britain had the largest workable ore deposits in the ancient Western world, this has led to much historical speculation and myth regarding the long-distance trading of tin from the Bronze Age onwards. Here we establish the first detailed chronology for tin, along with lead and copper deposition, into undisturbed ombrotrophic (rain-fed) peat bogs located at Bodmin Moor and Dartmoor in the centre of the British tin ore fields. Sustained elevated tin deposition is demonstrated clearly, with peaks occurring at 100-400 and 700-1000 calendar years AD - contemporaneous with the Roman and Anglo-Saxon periods respectively. While pre-Roman Iron Age tin exploitation undoubtedly took place, it was on a scale that did not result in convincingly enhanced deposition of the metal. The deposition of lead in the peat record provides evidence of a pre-Roman metal-based economy in southwest Britain. Emerging in the 4th century BC, this was centred on copper and lead ore processing that expanded exponentially and then collapsed upon Roman colonization during the 1st century AD. (C) 2011 Elsevier Ltd. All rights reserved.

Optimal design of cold-formed steel portal frames for stressed-skin action using genetic algorithm

This paper describes a stressed-skin diaphragm approach to the optimal design of the internal frame of a cold-formed steel portal framing system, in conjunction with the effect of semi-rigid joints. Both ultimate and serviceability limit states are considered. Wind load combinations are included. The designs are optimized using a real-coded niching genetic algorithm, in which both discrete and continuous decision variables are processed. For a building with two internal frames, it is shown that the material cost of the internal frame can be reduced by as much as 53%, compared with a design that ignores stressed-skin action.

Phenotypic characterization of an international Pseudomonas aeruginosa reference panel: strains of cystic fibrosis (CF) origin show less in vivo virulence than non-CF strains

Pseudomonas aeruginosa causes chronic lung infections in people with cystic fibrosis (CF) and acute opportunistic infections in people without CF. Forty two P. aeruginosa strains from a range of clinical and environmental sources were collated into a single reference strain panel to harmonise research on this diverse opportunistic pathogen. To facilitate further harmonized and comparable research on P. aeruginosa, we characterised the panel strains for growth rates, motility, virulence in the Galleria mellonella infection model, pyocyanin and alginate production, mucoid phenotype, lipopolysaccharide (LPS) pattern, biofilm formation, urease activity, antimicrobial and phage susceptibilities. Phenotypic diversity across the P. aeruginosa panel was apparent for all phenotypes examined agreeing with the marked variability seen in this species. However, except for growth rate, the phenotypic diversity among strains from CF versus non-CF sources was comparable. CF strains were less virulent in the G. mellonella model than non-CF strains (p=0.037). Transmissible CF strains generally lacked O antigen, produced less pyocyanin, and had low virulence in G. mellonella. Further, in the three sets of sequential CF strains, virulence, O-antigen expression and pyocyanin production were higher in the earlier isolate compared to the isolate obtained later in infection. Overall, full phenotypic characterization of the defined panel of P. aeruginosa strains increases our understanding of the virulence and pathogenesis of P. aeruginosa and may provide a valuable resource for the testing of novel therapies against this problematic pathogen.

Systematic Uncertainties Associated with the Cosmological Analysis of the First PAN-STARRS1 Type Ia Supernova Sample

We probe the systematic uncertainties from the 113 Type Ia supernovae (SN Ia) in the Pan-STARRS1 (PS1) sample along with 197 SN Ia from a combination of low-redshift surveys. The companion paper by Rest et al. describes the photometric measurements and cosmological inferences from the PS1 sample. The largest systematic uncertainty stems from the photometric calibration of the PS1 and low-z samples. We increase the sample of observed Calspec standards from 7 to 10 used to define the PS1 calibration system. The PS1 and SDSS-II calibration systems are compared and discrepancies up to ∼0.02 mag are recovered. We find uncertainties in the proper way to treat intrinsic colors and reddening produce differences in the recovered value of w up to 3%. We estimate masses of host galaxies of PS1 supernovae and detect an insignificant difference in distance residuals of the full sample of 0.037 ± 0.031 mag for host galaxies with high and low masses. Assuming flatness and including systematic uncertainties in our analysis of only SNe measurements, we find w = -1.120^+0.360_-0.206(Stat)^+0.269_-0.291(Sys). With additional constraints from Baryon acoustic oscillation, cosmic microwave background (CMB) (Planck) and H₀ measurements, we find w = -1.166^+0.072_-0.069 and Ω_m = 0.280^+0.013_-0.012 (statistical and systematic errors added in quadrature). The significance of the inconsistency with w = -1 depends on whether we use Planck or Wilkinson Microwave Anisotropy Probe measurements of the CMB: w_{BAO+H0+SN+WMAP} = -1.124^+0.083_-0.065.

The views of general practitioners on advance care planning for patients living with dementia

Background Advance care planning (ACP) facilitates communication
and understanding of preferences, nevertheless the use of
ACPs in primary care for patients with dementia is low. The disease’s
uncertain course and the inability to communicate with
the patient living with dementia are significant challenges for
GPs.
Aim The purpose of this study was to describe the attitudes and
practice preferences of GPs working within the UK’s National
Health System (NHS) regarding communication, and decisionmaking
for patients with dementia and their families
Methods A cross-sectional survey, using a purposive, cluster sample
of GPs across Northern Ireland with registered dementia
patients was used.
Results One hundred and thirty-three GPs (40.6%) participated
in the survey, representing 60.9% of surveyed practices. While
most respondents regarded dementia as a terminal disease
(96.2%) only 37.6% felt that palliative care applied equally from
the time of diagnosis to severe dementia. While most respondents
thought that early discussions would facilitate decision-making
during advanced dementia (61%), respondents were divided
on whether ACP should be initiated at the time of diagnoses
(39.8% in favour vs 45.8% disagreed). Interestingly, GPs who
were longer in practice placed greater importance on the presence
of an advance directive (F (2, 124) = 3.38, p = 0.037).
Discussion The timing of initiating ACP varies across individuals
requiring GPs to carefully consider strategies and receptiveness
of the patient and family carer.
Conclusion The findings promote both ongoing training in communication
and dementia management for GPs to meet the
needs of their patients living with dementia.