Developments in detection methods and use of superheated water as an eluent for liquid chromatography

A system has been developed to link superheated water liquid chromatography with flame ionisation detection. The system has been demonstrated to be robust, sensitive and have a linear response, therefore having advantages over existing commercial universal detectors, such as refractive index and evaporative light scattering detectors. A wide variety of compounds, such as non-volatiles and volatiles, with and without chromophores have not only been detected by flow injection analysis, but also separations have been demonstrated. The columns used have been polystyrene divinylbenzene, various ion exchange columns, Zirconia-PBD and porous graphitic carbon, all of which have been proven to be stable at the conditions required to produce superheated water. The separation of various mixtures have required pH control and the use of buffers, all of which have been found to be compatible with the system. The results obtained from the system using sugars, amino acids and polysaccharides, which cannot traditionally detected directly by FID or UV without derivatisation, have proven that detection is linear and detection limits are better than existing universal detectors. Also it has been demonstrated that compounds which are not detected by flame ionisation detection, such as ammonia, formaldehyde, dichloromethane and ionic compounds such as sodium nitrite, can be detected by the new system

The influence of the strength of bone on the deformation of acetabular shells : a laboratory experiment in cadavers

Date of Acceptance: 24/08/2014 ©2015 The British Editorial Society of Bone & Joint Surgery. The authors would like to thank N. Taylor (3D Measurement Company) for his work with regard to data acquisition and processing of experimental data. We would also like to thank Dr A. Blain of Newcastle University for performing the statistical analysis The research was supported by the NIHR Newcastle Biomedical Research Centre. The authors P. Dold, M. Flohr and R. Preuss are employed by Ceramtec GmbH. Martin Bone received a salary from the joint fund. The author or one or more of the authors have received or will receive benefits for personal or professional use from a commercial party related directly or indirectly to the subject of this article. This article was primary edited by G. Scott and first proof edited by J. Scott.Peer reviewedPostprin

Health psychology attendance: A multilevel analysis of patient-level predictors and therapist effects

The study investigated adult outpatient Health Psychology Services appointment attendance, cancellation, and missed appointments (A/C/M). The first objective was to determine which demographic and process factors predicted the probability of A/C/M. The second objective was to determine whether there remained residual significant differences in A/C/M between therapists (i.e., a “therapist effect”), after controlling for explanatory variables. We conducted a practice-based retrospective 2-year cohort study. Three-level multilevel models were constructed and tested to analyze the probability of A/C/M at (1) assessment appointments (N = 1,175) and (2) follow-up appointments (N = 5,441). After controlling for predictor variables, significant therapist effects were found for attendance (10.0% to 13.0%) and cancellation (4.4%) at follow-up appointments (but not assessments), indicating significantly different attendance rates at follow-up between therapists. Predictors of attendance at follow-up included patient age, pretherapy symptom severity scores (including risk and symptom scores), and completion of intake questionnaires. Early morning follow-up appointments were least likely to be canceled, followed by late afternoon and finally midday appointments. Treatment intensity predicted attendance, but among qualified therapists, qualification type and pay level were nonsignificant. No significant predictors of attendance at assessment were detected. Attendance at Health Psychology Services outpatient appointments varies significantly according to patient, therapist, and appointment factors. Key routinely collected variables are predictive of attendance at follow-up. Clinical implications include the potential to identify patients at risk of nonattendance and target engagement interventions to these patients. Research directions include closer examination of variability in follow-up attendance between therapists

Power asymmetries and punishment in a prisoner's dilemma with variable cooperative investment

In many two-player games, players that invest in punishment finish with lower payoffs than those who abstain from punishing. These results question the effectiveness of punishment at promoting cooperation, especially when retaliation is possible. It has been suggested that these findings may stem from the unrealistic assumption that all players are equal in terms of power. However, a previous empirical study which incorporated power asymmetries into an iterated prisoner's dilemma (IPD) game failed to show that power asymmetries stabilize cooperation when punishment is possible. Instead, players cooperated in response to their partner cooperating, and punishment did not yield any additional increase in tendency to cooperate. Nevertheless, this previous study only allowed an all-or-nothing–rather than a variable–cooperation investment. It is possible that power asymmetries increase the effectiveness of punishment from strong players only when players are able to vary their investment in cooperation. We tested this hypothesis using a modified IPD game which allowed players to vary their investment in cooperation in response to being punished. As in the previous study, punishment from strong players did not increase cooperation under any circumstances. Thus, in two-player games with symmetric strategy sets, punishment does not appear to increase cooperation

Switch from sexual to parthenogenetic reproduction in a zebra shark

Parthenogenesis is a natural form of asexual reproduction in which embryos develop in the absence of fertilisation. Most commonly found in plants and invertebrate organisms, an increasing number of vertebrate species have recently been reported employing this reproductive strategy. Here we use DNA genotyping to report the first demonstration of an intra-individual switch from sexual to parthenogenetic reproduction in a shark species, the zebra shark Stegostoma fasciatum. A co-housed, sexually produced daughter zebra shark also commenced parthenogenetic reproduction at the onset of maturity without any prior mating. The demonstration of parthenogenesis in these two conspecific individuals with different sexual histories provides further support that elasmobranch fishes may flexibly adapt their reproductive strategy to environmental circumstances

Head to head tests of the hydrodynamic support for Saturn V

Head to head tests on Saturn V hydrodynamic support to determine performance compared with mathematical model predictio

Pruritus is a common feature in sheep infected with the BSE agent.

BACKGROUND: The variability in the clinical or pathological presentation of transmissible spongiform encephalopathies (TSEs) in sheep, such as scrapie and bovine spongiform encephalopathy (BSE), has been attributed to prion protein genotype, strain, breed, clinical duration, dose, route and type of inoculum and the age at infection. The study aimed to describe the clinical signs in sheep infected with the BSE agent throughout its clinical course to determine whether the clinical signs were as variable as described for classical scrapie in sheep. The clinical signs were compared to BSE-negative sheep to assess if disease-specific clinical markers exist. RESULTS: Forty-seven (34%) of 139 sheep, which comprised 123 challenged sheep and 16 undosed controls, were positive for BSE. Affected sheep belonged to five different breeds and three different genotypes (ARQ/ARQ, VRQ/VRQ and AHQ/AHQ). None of the controls or BSE exposed sheep with ARR alleles were positive. Pruritus was present in 41 (87%) BSE positive sheep; the remaining six were judged to be pre-clinically infected. Testing of the response to scratching along the dorsum of a sheep proved to be a good indicator of clinical disease with a test sensitivity of 85% and specificity of 98% and usually coincided with weight loss. Clinical signs that were displayed significantly earlier in BSE positive cases compared to negative cases were behavioural changes, pruritic behaviour, a positive scratch test, alopecia, skin lesions, teeth grinding, tremor, ataxia, loss of weight and loss of body condition. The frequency and severity of each specific clinical sign usually increased with the progression of disease over a period of 16-20 weeks. CONCLUSION: Our results suggest that BSE in sheep presents with relatively uniform clinical signs, with pruritus of increased severity and abnormalities in behaviour or movement as the disease progressed. Based on the studied sheep, these clinical features appear to be independent of breed, affected genotype, dose, route of inoculation and whether BSE was passed into sheep from cattle or from other sheep, suggesting that the clinical phenotype of BSE is influenced by the TSE strain more than by other factors. The clinical phenotype of BSE in the genotypes and breed studied was indistinguishable from that described for classical scrapie cases