Interactions between the endocrine and immune systems in locusts

The prophenoloxidase cascade in the haemolymph of mature adult Locusta migratoria migratorioides (R & F) is activated in response to injection of laminarin, a -1,3 glucan. Co-injection of adipokinetic hormone-I (Lom-AKH-I) and laminarin prolongs the activation of the enzyme in a dose-dependent manner. However, injections of bacterial lipopolysaccharide (LPS) do not activate prophenoloxidase unless AKH is co-injected, when there is a dose-dependent increase in the level of phenoloxidase that persists in the haemolymph for several hours. Even when AKH is co-injected, the highest levels of phenoloxidase activity are always greater after injection of laminarin than after LPS, and these two immunogens must activate the prophenoloxidase cascade by quite distinct pathways. In the present study, interactions between the endocrine and immune systems were examined with respect to activation of prophenoloxidase and the formation of nodules: injection of LPS induces nodule formation in adult locusts. With LPS from Pseudomonas aeruginosa, nodules form exclusively in dense accumulations in the anterior portion of the abdomen on either side of the dorsal blood vessel associated with the dorsal diaphragm. However, with LPS from Escherichia coli, fewer nodules are formed but with a similar distribution, except that occasionally some nodules are aligned additionally on either side of the ventral nerve cord. Co-injection of Lom-AKH-I with LPS from either bacteria stimulates greater numbers of nodules to be formed. This effect of coinjection of AKH on nodule formation is seen at low doses of hormone with only 0.3 or 0.4 pmol of Lom-AKH-1, respectively, increasing the number of nodules by 50%. Injections of octopamine or 5-hydroxytryptamine do not mimic either of the actions of Lom-AKH-I described here. Co-injection of an angiotensin-converting enzyme inhibitor, captopril, reduces nodule formation in response to injections of LPS but has no effect on the activation of phenoloxidase. Co-injection of an inhibitor of eicosanoid synthesis, dexamethasone, with LPS influences nodule formation (with or without AKH) in different ways according to the dose of dexamethasone used, but does not affect activation of prophenoloxidase. Eicosanoid synthesis is important for nodule formation, but not for the activation of the prophenoloxidase cascade in locust haemolymph

Automatic normal orientation in point clouds of building interiors

Orienting surface normals correctly and consistently is a fundamental problem in geometry processing. Applications such as visualization, feature detection, and geometry reconstruction often rely on the availability of correctly oriented normals. Many existing approaches for automatic orientation of normals on meshes or point clouds make severe assumptions on the input data or the topology of the underlying object which are not applicable to real-world measurements of urban scenes. In contrast, our approach is specifically tailored to the challenging case of unstructured indoor point cloud scans of multi-story, multi-room buildings. We evaluate the correctness and speed of our approach on multiple real-world point cloud datasets

Radiation-induced insulator discharge pulses in the CRRES internal discharge monitor satellite experiment

The Internal Discharge Monitor (IDM) was designed to observe electrical pulses from common electrical insulators in space service. The sixteen insulator samples included twelve planar printed circuit boards and four cables. The samples were fully enclosed, mutually isolated, and space radiation penetrated 0.02 cm of aluminum before striking the samples. Pulsing began on the seventh orbit, the maximum pulse rate occurred on the seventeenth orbit when 13 pulses occurred, and the pulses slowly diminished to about one per 3 orbits six months later. After 8 months, the radiation belts abruptly increased and the pulse rates attained a new high. These pulse rates were in agreement with laboratory experience on shorter time scales. Several of the samples never pulsed. If the pulses were not confined within IDM, the physical processes could spread to become a full spacecraft anomaly. The IDM results indicate the rate at which small insulator pulses occur. Small pulses are the seeds of larger satellite electrical anomalies. The pulse rates are compared with space radiation intensities, L shell location, and spectral distributions from the radiation spectrometers on the Combined Release and Radiation Effects Satellite

Fat transforms ascorbic acid from inhibiting to promoting acid-catalysed N-nitrosation

<b>Background</b>: The major potential site of acid nitrosation is the proximal stomach, an anatomical site prone to a rising incidence of metaplasia and adenocarcinoma. Nitrite, a pre-carcinogen present in saliva, can be converted to nitrosating species and N-nitroso compounds by acidification at low gastric pH in the presence of thiocyanate. <b>Aims</b>: To assess the effect of lipid and ascorbic acid on the nitrosative chemistry under conditions simulating the human proximal stomach. <b>Methods</b>: The nitrosative chemistry was modelled in vitro by measuring the nitrosation of four secondary amines under conditions simulating the proximal stomach. The N-nitrosamines formed were measured by gas chromatography–ion-trap tandem mass spectrometry, while nitric oxide and oxygen levels were measured amperometrically. <b>Results</b>: In absence of lipid, nitrosative stress was inhibited by ascorbic acid through conversion of nitrosating species to nitric oxide. Addition of ascorbic acid reduced the amount of N-nitrosodimethylamine formed by fivefold, N-nitrosomorpholine by .1000-fold, and totally prevented the formation of N-nitrosodiethylamine and N-nitrosopiperidine. In contrast, when 10% lipid was present, ascorbic acid increased the amount of Nnitrosodimethylamine, N-nitrosodiethylamine and N-nitrosopiperidine formed by approximately 8-, 60- and 140-fold, respectively, compared with absence of ascorbic acid. <b>Conclusion</b>: The presence of lipid converts ascorbic acid from inhibiting to promoting acid nitrosation. This may be explained by nitric oxide, formed by ascorbic acid in the aqueous phase, being able to regenerate nitrosating species by reacting with oxygen in the lipid phase

First Principles Analysis of Electron-Phonon Interaction in Graphene

The electron-phonon interaction in monolayer graphene is investigated by using density functional perturbation theory. The results indicate that the electron-phonon interaction strength is of comparable magnitude for all four in-plane phonon branches and must be considered simultaneously. Moreover, the calculated scattering rates suggest an acoustic phonon contribution that is much weaker than previously thought, revealing the role of optical phonons even at low energies. Accordingly it is predicted, in good agreement with a recent measurement, that the intrinsic mobility of graphene may be more than an order of magnitude larger than the high values reported in suspended samples.Comment: 12 pages, 4 figure

Theory of Activated Transport in Bilayer Quantum Hall Systems

We analyze the transport properties of bilayer quantum Hall systems at total filling factor $\nu=1$ in drag geometries as a function of interlayer bias, in the limit where the disorder is sufficiently strong to unbind meron-antimeron pairs, the charged topological defects of the system. We compute the typical energy barrier for these objects to cross incompressible regions within the disordered system using a Hartree-Fock approach, and show how this leads to multiple activation energies when the system is biased. We then demonstrate using a bosonic Chern-Simons theory that in drag geometries, current in a single layer directly leads to forces on only two of the four types of merons, inducing dissipation only in the drive layer. Dissipation in the drag layer results from interactions among the merons, resulting in very different temperature dependences for the drag and drive layers, in qualitative agreement with experiment.Comment: 4 pages, 2 figure

Geometrical Defects in Josephson Junction Arrays

Dislocations and disclinations in a lattice of Josephson junctions will affect the dynamics of vortex excitations within the array. These defects effectively distort the space in which the excitations move and interact. The interaction energy between such defects and excitations are determined and vortex trajectories in twisted lattices are calculated. Finally, possible experiments observing these effects are presented.Comment: 26 pages including 5 figure

The Effect of Headphone Verses Room Music on Aerobic Performance

Please refer to the pdf version of the abstract located adjacent to the title

The disappearance of the "revolving door" patient in Scottish general practice: successful policies

<b>Background</b> We describe the health of "revolving door" patients in general practice in Scotland, estimate changes in their number over the timescale of the study, and explore reasons for changes, particularly related to NHS and government policy.<p></p> <b>Methods</b> A mixed methods predominantly qualitative study, using a grounded theory approach, set in Scottish general practice. Semi-structured interviews were conducted with professional key informants, 6 Practitioner Services staff who administer the GP registration system and 6 GPs with managerial or clinical experience of working with "revolving door" patients. Descriptive statistical analysis and qualitative analysis of patient removal episodes linked with routine hospital admissions, outpatient appointments, drug misuse treatment episodes and deaths were carried out with cohorts of "revolving door" patients identified from 1999 to 2005 in Scotland.<p></p> <b>Results</b> A "revolving door" patient is removed 4 or more times from GP lists in 7 years. Patients had complex health issues including substance misuse, psychiatric and physical health problems and were at high risk of dying. There was a dramatic reduction in the number of "revolving door" patients during the course of the study.<p></p> <b>Conclusions</b> "Revolving door" patients in general practice had significant health problems. Their numbers have reduced dramatically since 2004 and this probably resulted from improved drug treatment services, pressure from professional bodies to reduce patient removals and the positive ethical regulatory and financial climate of the 2004 GMS GP contract. This is a positive development for the NHS