Search for a light sterile neutrino at Daya Bay

A search for light sterile neutrino mixing was performed with the first 217 days of data from the Daya Bay Reactor Antineutrino Experiment. The experiment's unique configuration of multiple baselines from six 2.9 GW(th) nuclear reactors to six antineutrino detectors deployed in two near (effective baselines 512 m and 561 m) and one far (1579 m) underground experimental halls makes it possible to test for oscillations to a fourth (sterile) neutrino in the 10(-3) eV(2)<|Δm(41)(2) |< 0.3 eV(2) range. The relative spectral distortion due to the disappearance of electron antineutrinos was found to be consistent with that of the three-flavor oscillation model. The derived limits on sin(2) 2θ(14) cover the 10(-3) eV(2) ≲ |Δm(41)(2)| ≲ 0.1 eV(2) region, which was largely unexplored.

Evaluation of a user guidance reminder to improve the quality of electronic prescription messages

BACKGROUND

Prescribers' inappropriate use of the free-text Notes field in new electronic prescriptions can create confusion and workflow disruptions at receiving pharmacies that often necessitates contact with prescribers for clarification. The inclusion of inappropriate patient direction (Sig) information in the Notes field is particularly problematic.

OBJECTIVE

We evaluated the effect of a targeted watermark, an embedded overlay, reminder statement in the Notes field of an EHR-based e-prescribing application on the incidence of inappropriate patient directions (Sig) in the Notes field.

METHODS

E-prescriptions issued by the same exact cohort of 97 prescribers were collected over three time periods: baseline, three months after implementation of the reminder, and 15 months post implementation. Three certified and experienced pharmacy technicians independently reviewed all e-prescriptions for inappropriate Sig-related information in the Notes field. A physician reviewer served as the final adjudicator for e-prescriptions where the three reviewers could not reach a consensus. ANOVA and post hoc Tukey HSD tests were performed on group comparisons where statistical significance was evaluated at p<0.05.

RESULTS

The incidence of inappropriate Sig-related information in the Notes field decreased from a baseline of 2.8% to 1.8% three months post-implementation and remained stable after 15 months. In addition, prescribers' use of the Notes decreased by 22% after 3 months and had stabilized at 18.7% below baseline after 15 months.

CONCLUSION

Insertion of a targeted watermark reminder statement in the Notes field of an e-prescribing application significantly reduced the incidence of inappropriate Sig-related information in Notes and decreased prescribers' use of this field.

Smothering in UK free-range flocks. Part 1: incidence, location, timing and management

Smothering in poultry is an economic and welfare-related concern. This study presents the first results from a questionnaire addressing the incidence, location, timing and management of smothering of free-range farm managers from two commercial egg companies (representing 35 per cent of the UK free-range egg supply). Overall, nearly 60 per cent of farm mangers experienced smothering in their last flock, with an average of 25.5 birds lost per incidence, although per cent mortality due to smothering was low (x̄=1.6 per cent). The majority of farm managers also reported that over 50 per cent of all their flocks placed had been affected by smothering. The location and timing of smothering (excluding smothering in nest boxes) tended to be unpredictable and varied between farms. Blocking off corners/nest boxes and walking birds more frequently were identified as popular smothering reduction measures, although there was a wide variety of reduction measures reported overall. The motivation to implement reduction measures was related to a farm manager's previous experience of smothering. To our knowledge, this is the first study to provide a representative industry estimate on the incidence, location, timing and management of smothering. The results suggest that smothering is a common problem, unpredictable between flocks with no clear, effective reduction strategies. A follow-up study will investigate the correlations among smothering, disease and other welfare problems and may shed further light on management solutions.

Spectral measurement of electron antineutrino oscillation amplitude and frequency at Daya Bay

A measurement of the energy dependence of antineutrino disappearance at the Daya Bay reactor neutrino experiment is reported. Electron antineutrinos (ν¯(e)) from six 2.9  GW(th) reactors were detected with six detectors deployed in two near (effective baselines 512 and 561 m) and one far (1579 m) underground experimental halls. Using 217 days of data, 41 589 (203 809 and 92 912) antineutrino candidates were detected in the far hall (near halls). An improved measurement of the oscillation amplitude sin(2)2θ(13)=0.090(-0.009)(+0.008) and the first direct measurement of the ν¯(e) mass-squared difference |Δm(ee)2|=(2.59(-0.20)(+0.19))×10(-3)  eV2 is obtained using the observed ν¯(e) rates and energy spectra in a three-neutrino framework. This value of |Δm(ee)2| is consistent with |Δm(μμ)2| measured by muon neutrino disappearance, supporting the three-flavor oscillation model.

Cell junction remodeling in gingival tissue exposed to a microbial toxin

The gingival epithelium plays a key role in protecting the supporting structures of the teeth from bacteria and their products. In ex vivo experiments, we recently showed that the cytolethal distending toxin (Cdt) from the periodontal pathogen Aggregatibacter actinomycetemcomitans causes extensive damage to gingival tissue. Morphological changes included detachment of the keratinized outer layer, distention of spinous and basal cells in the oral epithelium, disruption of rete pegs, and apparent dissolution of cell junctions. Adherens junctions (zonula adherens) are essential for maintaining barrier function and integrity of gingival epithelium. Therefore, immunohistochemical and RT-PCR analyses of human gingival explants (HGX) and human gingival epithelial cells (HGEC) were utilized for a closer examination of the effects of the Cdt on E-cadherin, the key membrane component of adherens junctions. Although there was some variability among tissue donors, exposure of gingival tissue or isolated epithelial cells to the toxin generally resulted in a pronounced increase in the expression and cytosolic distribution of E-cadherin, accompanied by an increase in levels of the intracellular scaffolding proteins β-catenin and β-actin. These results indicate that the Cdt induced substantial remodeling of adherens junctions, with a potential impact on the barrier function of gingival epithelium.

ABBREVIATIONS

cytolethal distending toxin (Cdt), 4',6-diamidino-2-phenylindole (DAPI), human gingival epithelial cells (HGEC), human gingival explants (HGX), human gingival fibroblasts (HGF), transepithelial resistance (TER).

Insights into the mechanism of pyrrole polymerization catalysed by porphobilinogen deaminase: high-resolution X-ray studies of the Arabidopsis thaliana enzyme

The enzyme porphobilinogen deaminase (PBGD; hydroxymethylbilane synthase; EC 2.5.1.61) catalyses a key early step of the haem- and chlorophyll-biosynthesis pathways in which four molecules of the monopyrrole porphobilinogen are condensed to form a linear tetrapyrrole. The active site possesses an unusual dipyrromethane cofactor which is extended during the reaction by the sequential addition of the four substrate molecules. The cofactor is linked covalently to the enzyme through a thioether bridge to the invariant Cys254. Until recently, structural data have only been available for the Escherichia coli and human forms of the enzyme. The expression of a codon-optimized gene for PBGD from Arabidopsis thaliana (thale cress) has permitted for the first time the X-ray analysis of the enzyme from a higher plant species at 1.45 Å resolution. The A. thaliana structure differs appreciably from the E. coli and human forms of the enzyme in that the active site is shielded by an extensive well defined loop region (residues 60-70) formed by highly conserved residues. This loop is completely disordered and uncharacterized in the E. coli and human PBGD structures. The new structure establishes that the dipyrromethane cofactor of the enzyme has become oxidized to the dipyrromethenone form, with both pyrrole groups approximately coplanar. Modelling of an intermediate of the elongation process into the active site suggests that the interactions observed between the two pyrrole rings of the cofactor and the active-site residues are highly specific and are most likely to represent the catalytically relevant binding mode. During the elongation cycle, it is thought that domain movements cause the bound cofactor and polypyrrole intermediates to move past the catalytic machinery in a stepwise manner, thus permitting the binding of additional substrate moieties and completion of the tetrapyrrole product. Such a model would allow the condensation reactions to be driven by the extensive interactions that are observed between the enzyme and the dipyrromethane cofactor, coupled with acid-base catalysis provided by the invariant aspartate residue Asp95.

Comparison of short-term rainfall forecasts for model-based flow prediction in urban drainage systems

Forecast-based flow prediction in drainage systems can be used to implement real-time control of drainage systems. This study compares two different types of rainfall forecast - a radar rainfall extrapolation-based nowcast model and a numerical weather prediction model. The models are applied as input to an urban runoff model predicting the inlet flow to a waste water treatment plant. The modelled flows are auto-calibrated against real-time flow observations in order to certify the best possible forecast. Results show that it is possible to forecast flows with a lead time of 24 h. The best performance of the system is found using the radar nowcast for the short lead times and the weather model for larger lead times.

Crystallization and preliminary X-ray characterization of the tetrapyrrole-biosynthetic enzyme porphobilinogen deaminase from Arabidopsis thaliana

The enzyme porphobilinogen deaminase (PBGD; hydroxymethylbilane synthase; EC 2.5.1.61) catalyses a key early step of the haem-biosynthesis pathway in which four molecules of the monopyrrole porphobilinogen are condensed to form a linear tetrapyrrole. The enzyme possesses a dipyrromethane cofactor which is covalently linked by a thioether bridge to an invariant cysteine residue. Since PBGD catalyses a reaction which is common to the biosynthesis of both haem and chlorophyll, structural studies of a plant PBGD enzyme offer great potential for the discovery of novel herbicides. Until recently, structural data have only been available for the Escherichia coli and human forms of the enzyme. Expression in E. coli of a codon-optimized gene for Arabidopsis thaliana PBGD has permitted for the first time the crystallization and preliminary X-ray analysis of the enzyme from a plant species at high resolution.

Development of glioblastoma cell lines expressing red fluorescence for non-invasive live imaging of intracranial tumors

Glioblastoma (GBM) cell lines expressing red fluorescent proteins were evaluated as a tool for non-invasive imaging of orthotopic tumors.

MATERIALS AND METHODS

mKate2- and mCherry-transduced U251MG GBM lines were sorted by flow cytometry. The growth rates and drug sensitivity of the resulting cell lines were compared to those of the parental line. Following orthotopic implantation, mKate2-expressing cells were detected using multispectral imaging.

RESULTS

Flow cytometry-sorted fluorescent populations exhibiting growth curves that were comparable to those of the parental line were selected. mKate2-expressing cells were inoculated orthotopically and formed tumors which were visualized non-invasively, allowing monitoring of tumor growth over time and the assessment of tumor response to temozolomide drug treatment.

CONCLUSION

The strategy reported here led to the successful development of GBM models expressing mKate2 or mCherry. The fluorescence signal intensity measured in the brain of live animals correlates with tumor size, thus providing a method to assess tumor progression and response to treatment.