Observation of Quantum Shock Waves Created with Ultra Compressed Slow Light Pulses in a Bose-Einstein Condensate

We have used an extension of our slow light technique to provide a method for inducing small density defects in a Bose-Einstein condensate. These sub-resolution, micron-sized defects evolve into large amplitude sound waves. We present an experimental observation and theoretical investigation of the resulting breakdown of superfluidity. We observe directly the decay of the narrow density defects into solitons, the onset of the `snake' instability, and the subsequent nucleation of vortices.Comment: 15 pages, 5 figure

An Uncommon Presentation of Coxa Saltans: A Case Report

Coxa saltans, or “snapping hip,” refers to various conditions that produce a palpable or audible snapping of the hip after movement. We present an uncommon case of coxa saltans in a patient with a snapping proximal hamstring tendon. Findings of dynamic ultrasound evaluation were used to confirm the source of snapping, characterized by a lateral subluxation of the conjoint tendon over the ischial tuberosity. Our patient was treated nonoperatively, and we observed mild improvement of her symptoms. Few cases of similar pathological findings have been described, with varying causes of tendon instability. The results of the current case may help physicians in diagnosing and treating this condition

Distance metrics for heme protein electron tunneling

AbstractThere is no doubt that distance is the principal parameter that sets the order of magnitude for electron-tunneling rates in proteins. However, there continue to be varying ways to measure electron-tunneling distances in proteins. This distance uncertainty blurs the issue of whether the intervening protein medium has been naturally selected to speed or slow any particular electron-tunneling reaction. For redox cofactors lacking metals, an edge of the cofactor can be defined that approximates the extent in space that includes most of the wavefunction associated with its tunneling electron. Beyond this edge, the wavefunction tails off much more dramatically in space. The conjugated porphyrin ring seems a reasonable edge for the metal-free pheophytins and bacteriopheophytins of photosynthesis. For a metal containing redox cofactor such as heme, an appropriate cofactor edge is more ambiguous. Electron-tunneling distance may be measured from the conjugated heme macrocycle edge or from the metal, which can be up to 4.8 Å longer. In a typical protein medium, such a distance difference normally corresponds to a ~1000 fold decrease in tunneling rate. To address this ambiguity, we consider both natural heme protein electron transfer and light-activated electron transfer in ruthenated heme proteins. We find that the edge of the conjugated heme macrocycle provides a reliable and useful tunneling distance definition consistent with other biological electron-tunneling reactions. Furthermore, with this distance metric, heme axially- and edge-oriented electron transfers appear similar and equally well described by a simple square barrier tunneling model. This is in contrast to recent reports for metal-to-metal metrics that require exceptionally poor donor/acceptor couplings to explain heme axially-oriented electron transfers

Growth on Chitin Impacts the Transcriptome and Metabolite Profiles of Antibiotic-Producing Vibrio coralliilyticus S2052 and Photobacterium galatheae S2753

Members of the Vibrionaceae family are often associated with chitin-containing organisms, and they are thought to play a major role in chitin degradation. The purpose of the present study was to determine how chitin affects the transcriptome and metabolome of two bioactive Vibrionaceae strains, Vibrio coralliilyticus and Photobacterium galatheae. We focused on chitin degradation genes and secondary metabolites based on the assumption that these molecules in nature confer an advantage to the producer. Growth on chitin caused upregulation of genes related to chitin metabolism and of genes potentially involved in host colonization and/or infection. The expression of genes involved in secondary metabolism was also significantly affected by growth on chitin, in one case being 34-fold upregulated. This was reflected in the metabolome, where the antibiotics andrimid and holomycin were produced in larger amounts on chitin. Other polyketide synthase/ nonribosomal peptide synthetase (PKS-NRPS) clusters in P. galatheae were also strongly upregulated on chitin. Collectively, this suggests that both V. coralliilyticus and P. galatheae have a specific lifestyle for growth on chitin and that their secondary metabolites likely play a crucial role during chitin colonization. IMPORTANCE The bacterial family Vibrionaceae (vibrios) is considered a major player in the degradation of chitin, the most abundant polymer in the marine environment; however, the majority of studies on the topic have focused on a small number of Vibrio species. In this study, we analyzed the genomes of two vibrios to assess their genetic potential for the degradation of chitin. We then used transcriptomics and metabolomics to demonstrate that chitin strongly affects these vibrios at both the transcriptional and metabolic levels. We observed a strong increase in production of secondary metabolites, suggesting an ecological role for these molecules during chitin colonization in the marine environment

Responding to expectation? A examination of student expectation and subsequent experience of undergraduate study

This presentation discusses two emperical research studies- 1)responding to expectation and 2) expectation, experience and the conceptualisation of HE. It covers motivation for undergraduate study, motivation relating to choice of subject, expectations of higher education, and students' experiences.Funded by the Learning and Teaching Institute small grant scheme

Development and Validation of a LC-MS/MS Assay for Quantification of Parathyroid Hormone (PTH 1-34) in human Plasma

Background: Teriparatide [recombinant human PTH (1-34)] is an osteoanabolic agent for treatment of osteoporosis. The effect on bone decreases the risk of vertebral and non-vertebral fractures and increases bone mineral density (BMD) in post-menopausal women with osteoporosis. Measurement of PTH (1-34) is valuable in assessing treatment response and concordance with therapy.Aim: To develop and validate a method for quantification of PTH (1-34) using Liquid chromatography tandem mass spectrometry (LC-MS/MS) and to perform comparison with a commercial immunoassay.  Method: Sample extraction was developed using a Waters (Milford, MA, USA) Oasis® HLB µElution solid phase extraction. Quantification m/z transition 589>656 was used on Waters/Micromass® Quattro Ultima™ Pt mass spectrometer to measure PTH (1-34) in human plasma using rat PTH (1-34) as internal standard. Validation criteria were carried out against industry standards. PTH (1-34) results obtained from human subjects given Teriparatide (Fortsteo, Eli Lilly, IN, USA) (n=390) were compared against results obtained from an immunoassay (IDS; Boldon Tyne and Wear. UK).  Results and Discussion: LC-MS/MS produced a linear calibration curve from 10 to 2000 pg/mL (r2 >0.990). The LLoQ and LLoD for PTH (1-34) were 10 pg/mL and 2.1 pg/mL respectively. The inter- /intra-assay precision (CV%) of the method were 98.3% for four QCs (20, 100, 200, and 800 pg/mL). The mean recovery of PTH (1-34) was 107.2%. Method comparison between the LC-MS/MS and immunoassay using human EDTA plasma samples showed a high correlation (r2 = 0.950). A concentration-dependent, negative bias of 35.5% was observed across the range of 0 – 800 pg/mL. The immunoassay showed a 7% cross reactivity to human PTH (1-84) and 44% to rat PTH (1-34), no interference was observed in the LC-MS/MS method. Matrix effect and cross reactivity to human PTH (1-84) in the immunoassay were the likely contributing factors to the bias between the methods. The oxidised form of PTH (1-34) does not interfere with our LC-MS/MS method.  Conclusion: Our LC-MS/MS method demonstrated linearity over the calibration range, good precision and accuracy, excellent analyte recovery, and negligible matrix effects. The method was successfully used for measurements of PTH (1-34) in rat and human plasma