bluuebunny/crossref_metadata_2025 huggingface dataset:
Single channels activated by high concentrations of GABA in superior cervical ganglion neurones of the rat.
Authors: Newland C F , Colquhoun D , Cull‐Candy S G
Published: December 2014

1. Single‐channel currents evoked by high concentrations of GABA (10‐2000 microM) have been analysed to investigate the characteristics of GABAA receptor channels in outside‐out patches from rat sympathetic neurones. When high concentrations of GABA were applied to a patch, channel openings occurred in prolonged clusters (3.8 +/‐ 3.7 s (mean +/‐ S.D.) at 50 microM‐GABA) consisting, on average, of 350 apparent openings per cluster. Individual clusters were separated by long silent intervals. 2. Channel openings were to many (often ill‐defined) conductance states (range 7‐36 pS), but the most frequently observed conductance level was approximately 30 pS, (29.6 +/‐ 0.34 pS). Only these clusters during which the channel was open to this main state conductance for at least 95% of the cluster open time were used in the analysis of probability of being open. Other less frequently observed conductance levels were 15‐18 and 22‐23 pS, while levels of 33‐36 and 7‐9 pS were occasionally, but reliably, observed. 3. Bursts within clusters were defined as a series of openings separated by closed intervals shorter than some critical value, tc. At 50 microM‐GABA the mean burst length was 439 +/‐ 434 ms (+/‐ S.D., tc = 50 ms). 4. The probability of being open, po, during bursts within clusters has been analysed as a function of GABA concentration. As expected, increasing the concentration of GABA resulted in an overall increase in po. However, for a given agonist concentration there was a wide spread in po, far greater than that predicted for a population of identical and independent receptor channels (demonstrated by comparison with stimulated channel activity). 5. The wide range of po values at a particular concentration of GABA was not due to inappropriate selection of tc. At 50 microM‐GABA the range of po values was similar for tc of 20‐1000 ms, although the overall mean po became lower (0.64 rather than 0.81). 6. On the basis of simulated channel activity, it appears that most clusters which do not contain multiple openings, arise from the activity of one individual channel. Furthermore, there was no detectable tendency for gaps between bursts to be shorter in the middle of a cluster than at its ends. Therefore it is unlikely that variability in po arose from overlapping activity of two or more channels. 7. The values for po, mean open time, and mean shut time for bursts within the same cluster, and between different clusters, were compared by a randomization test.(ABSTRACT TRUNCATED AT 400 WORDS)
Task‐dependent changes in the responses to low‐threshold cutaneous afferent volleys in the human lower limb.
Authors: Burke D , Dickson H G , Skuse N F
Published: December 2014

1. In seven human subjects who were standing without support the sural nerves were stimulated electrically using trains of non‐painful stimuli (five pulses at 300 Hz), designed to activate afferents from cutaneous mechanoreceptors. The reflex effects of the stimulus train on different muscles of the ipsilateral and contralateral legs were sought in post‐stimulus averages of rectified EMG. Changes in the pattern of reflex influence were investigated when the subjects maintained different postures. 2. Clear reflex responses were seen in ipsilateral tibialis anterior, soleus, biceps femoris and vastus lateralis, but only when the muscles were actively contracting. In each muscle, inhibition was the dominant reflex response within the first 100 ms. In four of the seven subjects, reflex changes were detectable in the contralateral tibialis anterior and soleus, the peak‐to‐peak modulation within the first 200 ms being 25‐50% of that for the homologous ipsilateral muscle. 3. When subjects attempted to stand on a tilted platform, an unstable platform or on one leg with the other flexed, different combinations of muscles were active, involving both flexors and extensors or predominantly flexors or predominantly extensors. In each posture the reflex effects were demonstrable only in the active muscles. 4. With ipsilateral tibialis anterior, there were task‐dependent changes in the short‐latency components of the EMG response, approximately 60 ms and 80 ms after the stimulus. When seated performing voluntary contractions these components were difficult to define, and when standing on a platform tilted toe‐up they were small. When the ipsilateral leg was flexed or when standing on an unstable base, these early components were more prominent in each subject. With contralateral tibialis anterior, the dominant reflex pattern was inhibition when seated and contracting voluntarily, and facilitation during bipedal stance tilted toe‐up. These changes in reflex pattern could not be explained by different levels of background contraction. 5. It is concluded that cutaneous mechanoreceptors of the foot have widespread reflex actions on muscles throughout both limbs, particularly the ipsilateral limb, and that the reflex pattern in different muscles and within a single muscle may change dependent on the task that the subject is undertaking. These task‐dependent changes indicate plasticity in the expression of cutaneous reflex activity, affecting both short‐latency spinal as well as long‐latency pathways.
Haemodynamic and renal tubular effects of low doses of endothelin in anaesthetized rats.
Authors: Harris P J , Zhuo J , Mendelsohn F A , Skinner S L
Published: December 2014

1. Renal haemodynamic and tubular transport responses to low‐dose infusions (1 and 10 ng kg‐1 min‐1) of endothelin were investigated in anaesthetized rats. 2. Both doses caused transient increases in mean arterial blood pressure (17 +/‐ 5 mmHg, P < 0.05 at 1 ng kg‐1 min‐1) followed by sustained hypotension (‐14 +/‐ 5 mmHg, P < 0.05), reduced renal vascular resistance (‐42%, P < 0.05) and increased renal plasma flow (46%, P < 0.05). Glomerular filtration rate was unchanged. 3. Each dose caused profound diuresis and natriuresis. At 1 ng kg‐1 min‐1 urine flow rate and fractional water excretion increased 5‐fold and fractional sodium excretion 10‐fold. Fractional potassium excretion and solute‐free water clearance were unaltered. 4. End‐proximal fluid delivery estimated by lithium clearance doubled (P < 0.05) and fractional proximal and distal sodium reabsorption decreased 10‐20% (P < 0.05). Absolute proximal reabsorption also fell with the higher dose. 5. Hypotension and natriuresis persisted for 30 min after terminating infusions. Time‐control animals showed no changes in haemodynamics or renal tubular transport. 6. It is concluded that endothelin, at low concentrations, causes renal vasodilatation with concomitant natriuresis due to reduced sodium transport in proximal and distal nephron segments.
Role of K+ channels in spontaneous electrical and mechanical activity of smooth muscle in the guinea‐pig mesotubarium.
Authors: Lydrup M L
Published: December 2014

1. The spontaneous electrical and mechanical activity and the efflux rate of 86Rb+ in the guinea‐pig mesotubarium were studied in the presence of agents interacting with K+ channels. 2. Tetraethylammonium (TEA, 10 mM) increased the amplitude of the action potentials while having no consistent effect on the frequency or amplitude of spontaneous contractions. 3. 4‐Aminopyridine (4‐AP, 1‐5 mM) caused a graded increase in the duration of the contractions and of the electrical slow waves, and a decrease in the duration of the relaxed period between contractions. At 4 mM‐4‐AP or more the cell was unable to repolarize from the slow wave and the membrane depolarized to ‐26 mV from the normal resting potential of ‐63 mV. The rate of 86Rb+ efflux in the presence of 5 mM‐4‐AP was higher than that at 60 mM‐K+, where the membrane potential is ‐24 mV. 4. 4‐AP (5 mM) evoked a contracture in Ca(2+)‐free solution, containing 1 mM‐EGTA, both at the normal [K+]o of 5.9 mM and at 60 mM‐K+, suggesting release of intracellular Ca2+. 5. Apamin (0.1‐1 microM) and charybdotoxin (1‐10 nM), blockers of Ca(2+)‐dependent K+ channels, were without effects on the spontaneous electrical and mechanical activity. 6. The K+ channel opener pinacidil (10 microM) inhibited the spontaneous contractions and hyperpolarized the membrane by about 7 mV. The permeability to 86Rb+ was increased by a factor of 1.4. 7. It is concluded that different K+ channels are involved in the generation of spikes and slow waves: one sensitive to TEA and responsible for repolarization of the individual action potential, and another sensitive to 4‐AP and responsible for repolarization of the slow wave. The duration of the relaxed period can be influenced by activation of K+ channels sensitive to pinacidil.
The renal vascular response to mild and severe haemorrhage in the anaesthetized rat.
Authors: Shirley D G , MacRae K D , Walker J
Published: December 2014

1. In order to document the characteristics of the renal vascular response to blood losses of varying severity, Inactin‐anaesthetized rats were subjected to a haemorrhage of 5, 10, 15 or 20 ml (kg body weight)‐1, while a fifth group (control rats) remained unbled. Radioactive microspheres (diameter 10 microns) were used to determine cardiac output, total renal blood flow and the distribution of blood flow within the kidneys; measurements were made before and 5‐120 min after haemorrhage. 2. In control animals none of the variables studied changed significantly during the experimental period. 3. Immediately after haemorrhage there were reductions in arterial pressure and cardiac output which were roughly proportional to the severity of haemorrhage. Arterial pressure recovered to some extent during the next 30 min, then stabilized; cardiac output recovered only slightly. 4. Total renal blood flow fell to an extent dependent on the degree of haemorrhage, with no evidence of subsequent recovery. The approximate reductions in renal blood flow were 2% (n.s.), 15%, 30% and 50% after bleeds of 5, 10, 15 and 20 ml kg‐1, respectively. Renal vascular resistance increased consistently only in the groups bled 15 and 20 ml kg‐1. When renal blood flow was expressed as a fraction of cardiac output, it increased during the period immediately after haemorrhage, indicating some degree of ‘protection’ of the renal circulation in the face of hypotension. 5. Measurements of intrarenal blood flow indicated a significantly reduced flow to the superficial cortex after every degree of haemorrhage. Inner cortical flow was less affected and fell significantly only in the groups bled 15 and 20 ml kg‐1; blood flow to the mid‐cortex was intermediate.
Capsaicin‐sensitive sensory neurons are involved in the plasma catecholamine response of rats to selective stressors.
Authors: Zhou X F , Livett B G
Published: December 2014

1. The effect of capsaicin pre‐treatment on adrenal catecholamine (CA) secretion in response to stress is controversial. In earlier experiments performed under pentobarbitone anaesthesia, the release of CA in response to stress was complicated by the effects of the barbiturate anaesthesia. 2. In the present study we have used conscious freely moving rats with indwelling cannulae to study the effect of neonatal capsaicin pre‐treatment on the plasma CA response to different types of stressors (swimming stress, hypovolaemic stress, immobilization stress and cold stress). 3. After swimming for 20 min, plasma noradrenaline (NA) levels increased by 8‐fold and adrenaline by 2‐fold in control rats. The increase in plasma NA levels in the capsaicin group was attenuated at 10 min of swimming compared with the vehicle group (P < 0.05). 4. With hypovolaemic stress, there were no differences in plasma CA levels, blood pressure and heart rate between the capsaicin group and the vehicle group. There were also no differences in plasma CA levels after immobilization stress between the two groups. 5. With cold stress, plasma NA levels increased 5‐fold and adrenaline levels by 3‐fold over basal at 45 min in the vehicle pre‐treated rats. This increase was not observed in the capsaicin group. 6. Immunoreactive substance P was depleted by only 68% in the splanchnic nerve following capsaicin pre‐treatment. If the remaining 32% was biologically active substance P then it could account for the maintenance of the response to hypovolaemic and immobilization stress. However, it might be possible that the responses to hypovolaemic and immobilization stresses could be attenuated if a more complete depletion were achieved. 7. These results in conscious rats indicate that capsaicin‐sensitive sensory neurons are required for plasma CA response to selective stressors. They are required for CA output in response to cold stress and to the early phase of swimming stress, but not to hypovolaemic stress and immobilization stress.
Reversal by omeprazole of the depression of gastrin cell function by fasting in the rat.
Authors: Dimaline R , Evans D , Varro A , Dockray G J
Published: December 2014

1. Gastrin (G)‐cell function is controlled by gastric acid, which has inhibitory effects, and food in the gastric lumen, which has stimulatory effects. We have examined the role of acid in mediating the depression of G‐cell function that occurs in fasting in the rat. 2. Rats were fasted for 48 h, and received either the H(+)‐K(+)‐ATPase inhibitor omeprazole, to reduce acid secretion, or vehicle. Basal acid secretion was not significantly different after fasting for 24 or 48 h. Fasted rats which received omeprazole were achlorhydric. 3. In rats treated with vehicle and fasted for 48 h, plasma and tissue gastrin concentrations were significantly depressed. The fall in both parameters suggests an inhibition of gastrin synthesis and consistent with this a decrease was observed in tissue gastrin mRNA abundance and in phosphorylation of progastrin‐derived peptides. 4. In fasted rats treated with omeprazole, tissue gastrin concentrations were not significantly different from those of rats fed ad libitum, but plasma gastrin concentrations were significantly higher than in rats fed ad libitum. Gastrin mRNA abundance and the phosphorylation of progastrin‐derived peptides in omeprazole‐treated rats was not significantly different from rats fed ad libitum. 5. The data suggest that the depression of G‐cell function which occurs in fasted rats can be attributed to the inhibitory action of intraluminal acid on the G‐cell. Gastric acid appears to regulate several different aspects of G‐cell function, including gastrin synthesis, post‐translational processing and secretion.
Calcium release induced by inositol 1,4,5‐trisphosphate in single rabbit intestinal smooth muscle cells.
Authors: Komori S , Bolton T B
Published: December 2014

1. Single smooth muscle cells were isolated by enzymic digestion from the longitudinal muscle layer of rabbit jejunum, and the response of the cells to calcium (Ca2+) release by InsP3 (D‐myo‐inositol 1,4,5‐trisphosphate) was studied. Changes in internal Ca2+ concentration were monitored by measuring Ca(2+)‐activated K+ currents (outward currents) using the whole‐cell voltage‐clamp technique. 2. At break‐through from cell‐attached patch to whole‐cell recording mode using a 100 microM‐InsP3‐filled pipette, cells exhibited a brief outward current which reached its peak in 1.1 s and terminated within 10 s. Following this the generation of spontaneous transient outward currents (STOCs) was inhibited. (STOCs are considered to represent bursts of openings of Ca(2+)‐activated K+ channels in response to spontaneous discharges of Ca2+ from the stores.) When a pipette filled with 20 microM‐InsP3 was used, similar current responses were also evoked, but some cells failed to respond. 3. The InsP3‐induced outward current at membrane break‐through was similar in size and time course to the outward current response of normal cells to bath‐applied carbachol (CCh, 100 microM) or caffeine (20 mM). 4. Dialysis with InsP3‐containing solution inhibited the caffeine‐induced outward current, depending on the pipette InsP3 concentration. Inclusion of heparin (5 mg/ml) in the pipette completely prevented inhibition by InsP3 of the caffeine response and of STOC discharge. However, the InsP3‐induced current at break‐through remained unchanged, probably because of the slower rate of diffusion of heparin. 5. In cells dialysed with pipette solution containing 30 or 100 microM‐caged InsP3, flash photolysis (producing up to 1.5 microM‐InsP3) induced an outward current response after a latency of 31.0 +/‐ 1.8 ms (n = 15), which was followed by inhibition of STOCs. The reversal potential of the current to flash‐release of InsP3 followed closely the Nernst potential for K+ ions (EK), suggesting negligible contributions from channels other than Ca(2+)‐activated K+ channels. 6. Photolysis of caged InsP3 (30 or 100 microM) still produced a current response after 3‐6 min in Ca(2+)‐free (3 mM‐EGTA added) bathing solution, but no response occurred if the cell was exposed to either caffeine (20 mM) or CCh (100 microM) to deplete Ca stores.(ABSTRACT TRUNCATED AT 400 WORDS)
Separate agonist‐specific oscillatory mechanisms in cultured human sweat duct cells.
Authors: Pedersen P S
Published: December 2014

1. Cultured sweat duct cells (CSDCs) were grown to confluency on a permeable support, and the pharmacological ion transport regulation was assayed by transepithelial voltage clamp techniques. 2. Exposure of the serosal membrane of CSDCs to methacholine (MCh), lysylbradykinin (LBK) or histamine produced an oscillating short‐circuit current (Iscc) response, which could be divided in an initial transient phase and a sustained oscillating phase, the latter of which was totally dependent on external Ca2+. 3. The Iscc responses evoked by LBK and histamine were, in contrast to the cholinergic response, characterized by a marked desensitization and short duration of the subsequent phase of Iscc oscillations. 4. Prolonged Iscc oscillations, reflecting continuous Ca2+ influx, were seen following MCh stimulation, and in response to LBK or histamine stimulation, when cells had been pre‐treated with MCh. This pre‐treatment effect of MCh was independent of continuous muscarinic receptor occupation, and it was unrelated to nicotinic receptor occupation. 5. It is suggested that MCh stimulation selectively initiates an influx of Ca2+ to an intracellular pool, from where Ca2+ can be discharged repetitively. In contrast, LBK and histamine only activate discharge of Ca2+ from such an intracellular pool, resulting in a limited response, given no prior stimulation by MCh of the Ca2+ influx mechanism.
Nuclear Power as a Basis for Future Electricity Generation
Authors: Pioro I. , Duffey R.
Published: December 2014

It is well known that electrical power generation is the key factor for advances in industry, agriculture, technology, and standards of living. Also, a strong power industry with diverse energy sources is very important for a nation’s independence. In general, electrical energy can be generated from (1) burning mined and refined energy sources such as coal, natural gas, oil, and nuclear; and (2) harnessing energy sources such as hydro, biomass, wind, geothermal, solar, and wave power. Today, the main sources for electrical energy generation are (1) thermal power, primarily using coal and secondarily natural gas; (2) “large” hydraulic power from dams and rivers; and (3) nuclear power from various reactor designs. The balance of the energy sources is from using oil, biomass, wind, geothermal, and solar, which have a visible impact just in some countries. This paper presents the current status and role of the nuclear-power industry in the world with a comparison of nuclear-energy systems to other energy systems.
Investigation of the Circumferential Static Pressure Non-Uniformity Caused by a Centrifugal Compressor Discharge Volute
Authors: Sorokes James M. , Borer Cyril J. , Koch Jay M.
Published: December 2014

The paper describes experimental and computational fluid dynamics analyses of the non-uniform static pressure distortion caused by the discharge volute in a high pressure, centrifugal compressor. The experiments described in this paper were done using a heavily instrumented gas re-injection compressor operating at over 6000 psia discharge. Instrumentation was installed to measure static, total, and dynamic pressure as well as impeller strain and mechanical vibrations. A brief description of the compressor and instrumentation are provided.

Concurrent with the experimental work, CFD runs were completed to study the reasons for the pressure non-uniformity. The CFD pressure profile trends agreed well with the experimental results and provided analytical corroboration for the conclusions drawn from the test data.

Conclusions are drawn regarding: a) the response of the non-uniformity to changing flow rates; b) the extent to which the non-uniformity can be detected upstream of the impeller; and c) the mechanical influences of the non-uniformity on the impellers.
Influence of Axial Compressor Fouling on Gas Turbine Unit Perfomance Based on Different Schemes and With Different Initial Parameters
Authors: Tarabrin A. P. , Schurovsky V. A. , Bodrov A. I. , Stalder J.-P.
Published: December 2014

This paper presents an attempt of a quantitative evaluation of deterioration, due to fouling, in the performance of gas turbine units of different schemes (one-shaft, two-shaft and three-shaft) but with axial compressors of the same type and dimensions. This paper also examines the influence of the gas turbine unit initial parameters (inlet turbine temperature and pressure ratio) on the gas turbine unit sensitivity to axial compressor fouling. The evaluation of the gas turbine unit sensitivity to fouling is performed based on the small deviations method. The index of sensitivity to fouling (ISF) proposed in (Tarabrin et al, 1996) is used. It is proposed that not only the ISF characterizing the axial compressor sensitivity to fouling but also the scheme and the initial gas turbine unit parameters influencing the gas turbine unit sensitivity to axial compressor fouling, should be taken into consideration.
Dry Low Emissions Premixer CCD Modeling and Validation
Authors: Hura Harjit S. , Joshi Narendra D. , Mongia Hukam C. , Tonouchi Jon
Published: December 2014

Computational Combustion Dynamics has been used extensively at General Electric Company for combustion applications. This paper demonstrates an application of Advanced Combustion Code to GE’s lean premixed dry low NOx emissions LM2500 and LM6000 gas turbine combustors. A methodology for anchoring the Double Annular Counter-Rotating Swirler (DACRS) exit conditions to Laser Doppler Velocity data from a reacting single cup experiment is described. The DACRS exit velocity profiles and turbulence parameters are inlet boundary conditions for the annular combustor simulation. Since over 80 per cent of the total air enters the combustor via the premixers, inaccuracies in these boundary conditions have a significant impact on the predicted flame shape, liner temperatures and emissions.

The paper shows comparisons between measured and predicted velocity in a rectangular duct equipped with a single DACRS. The k-ε turbulence model and the two-step eddy break up/eddy dissipation combustion models are used to predict the reacting flow field of the natural gas/air flame. The inlet velocity profiles are developed first to match the LV data and the observed flame impingement location at nominal settings of the inlet turbulence parameters. The sum square error between measured and predicted velocity is used as the optimization function. Next, a design of experiment computational study is conducted to determine the inlet turbulence length scale and kinetic energy in order to further improve the data match. The eddy break up model is shown to be more robust than the eddy dissipation model. The eddy dissipation model resulted in slow combustion rates, and high fuel and carbon monoxide emissions.
An Experimental Study of Tip Clearance Flow in a Radial Inflow Turbine
Authors: Dambach R. , Hodson H. P. , Huntsman I.
Published: December 2014

This paper describes an experimental investigation of tip clearance flow in a radial inflow turbine. Flow visualisation and static pressure measurements were performed. These were combined with hot-wire traverses into the tip gap. The experimental data indicates that the tip clearance flow in a radial turbine can be divided into three regions. The first region is located at the rotor inlet, where the influence of relative casing motion dominates the flow over the tip. The second region is located towards midchord, where the effect of relative casing motion is weakened. Finally a third region exists in the exducer, where the effect of relative casing motion becomes small and the leakage flow resembles the tip flow behaviour in an axial turbine.

Integration of the velocity profiles showed that there is little tip leakage in the first part of the rotor because of the effect of scraping. It was found that the bulk of tip leakage flow in a radial turbine passes through the exducer. The mass flow rate, measured at four chordwise positions, was compared with a standard axial turbine tip leakage model. The result revealed the need for a model suited to radial turbines. The hot-wire measurements also indicated a higher tip gap loss in the exducer of the radial turbine. This explains why the stage efficiency of a radial inflow turbine is more affected by increasing the radial clearance than by increasing the axial clearance.
Prediction of Resonant Response of Shrouded Blades With 3D Shroud Constraint
Authors: Yang B. D. , Chen J. J. , Menq C. H.
Published: December 2014

In this paper, the 3D shroud contact kinematics of a shrouded blade system is studied. The assumed blade motion has three components, namely axial, tangential, and radial components, which result in a three dimensional relative motion across the shroud interface. The resulting relative motion can be decomposed into two components. The first one is on the contact plane and can induce stick-slip friction. The other component is perpendicular to the contact plane and can cause variation of the contact normal load and, in extreme circumstances, separation of the two contacting surfaces. In order to estimate the equivalent stiffness and damping of the shroud contact an approach is proposed. In this approach, the in-plane slip motion is assumed to be elliptical and is decomposed into two linear motions along the principal major and minor axes of the ellipse. A variable normal load friction force model (Yang and Menq, 1996) is then applied separately to each individual linear motion, and the equivalent stiffness and damping of the shroud contact can be approximately estimated. With the estimated stiffness and damping, the developed shroud contact model is applied to the prediction of the resonant response of a shrouded blade system. The effects of two different shroud constraint conditions, namely 2D constraint and 3D constraint, on the resonant response of a shrouded blade system are compared and the results are discussed.
Prediction of the Resonant Response of Frictionally Constrained Blade Systems Using Constrained Mode Shapes
Authors: Chen J. J. , Menq C. H.
Published: December 2014

In this paper, the concept of constrained mode shapes is employed to predict the resonant response of a frictionally constrained blade system. For a tuned blade system, the constrained mode shapes can be calculated using a finite element model of a single blade along with the cyclic symmetry constraint that simulates a fully stuck friction contact. The resulting constrained mode shapes are often complex and can be used to obtain the constrained receptance of the frictionally constrained blade. It is shown that by examining each mode’s contribution to the receptance at the friction contact point, the importance of each individual modes to the prediction of the resonant response of a frictionally constrained blade can be determined. Furthermore, by comparing the receptances calculated from free mode shapes and those from constrained mode shapes, it is found that in the neighborhood of the fully slipping region, the prediction of resonant response requires fewer number of modes when using free mode shapes compared to using constrained mode shapes. On the other hand, in the neighborhood of the fully stuck region, it requires fewer number of modes if constrained mode shapes are used. Therefore, when high preload at the friction contact is desirable, such as for shrouded blade systems, using the constrained mode shapes for the prediction of resonant response is preferred. Moreover, the concept of hybrid receptance is introduced so as to yield very accurate prediction of the resonant response based on only very few vibration modes.
Automatic Blade Repair System Based on Reverse Engineering Strategies
Authors: Bremer Claus
Published: December 2014

The compressor and turbine blades of aircraft engines and gas turbines have to be overhauled at regular intervals. First, the worn out blades are welded manually or by a welding robot. After welding, the blades will normally be shaped by hand, using grinding bands. Automation of the shaping of the welded beads reduces costs and process time while giving higher accuracy and quality. The following repair technique has been found to allow automatic tooling of the weld on final domains of blades, via a chain of processes, which run on one, single standard, three axis machining center. 1) Digitization of blade cross sections below the welded bead; 2) Calculation of the nominal geometry of the final domains; 3) Calculation of the NC processing programs; 4) NC processing of the final domains of the blades. The complete repair for one blade (steps 1 to 4) takes two to three minutes. The 3D digitizing system captures the actual geometry and chucking position of the blades completely. Therefore, no CAD data or measuring data of a master piece are required and the free chucking position of the blades allows simple fixtures. The blades can be repaired without user interaction, individually or in a batch quantity.
GPU‐based prompt gamma ray imaging from boron neutron capture therapy
Authors: Yoon Do‐Kun , Jung Joo‐Young , Jo Hong Key , Sil Lee Keum , Suk Suh Tae
Published: December 2014

Purpose:

The purpose of this research is to perform the fast reconstruction of a prompt gamma ray image using a graphics processing unit (GPU) computation from boron neutron capture therapy (BNCT) simulations.

Methods:

To evaluate the accuracy of the reconstructed image, a phantom including four boron uptake regions (BURs) was used in the simulation. After the Monte Carlo simulation of the BNCT, the modified ordered subset expectation maximization reconstruction algorithm using the GPU computation was used to reconstruct the images with fewer projections. The computation times for image reconstruction were compared between the GPU and the central processing unit (CPU). Also, the accuracy of the reconstructed image was evaluated by a receiver operating characteristic (ROC) curve analysis.

Results:

The image reconstruction time using the GPU was 196 times faster than the conventional reconstruction time using the CPU. For the four BURs, the area under curve values from the ROC curve were 0.6726 (A‐region), 0.6890 (B‐region), 0.7384 (C‐region), and 0.8009 (D‐region).

Conclusions:

The tomographic image using the prompt gamma ray event from the BNCT simulation was acquired using the GPU computation in order to perform a fast reconstruction during treatment. The authors verified the feasibility of the prompt gamma ray image reconstruction using the GPU computation for BNCT simulations.
Characterization of the Exradin W1 scintillator for use in radiotherapy
Authors: Carrasco P. , Jornet N. , Jordi O. , Lizondo M. , Latorre‐Musoll A. , Eudaldo T. , Ruiz A. , Ribas M.
Published: December 2014

Purpose:

To evaluate the main characteristics of the Exradin W1 scintillator as a dosimeter and to estimate measurement uncertainties when used in radiotherapy.

Methods:

We studied the calibration procedure, energy and modality dependence, short‐term repeatability, dose‐response linearity, angular dependence, temperature dependence, time to reach thermal equilibrium, dose‐rate dependence, water‐equivalent depth of the effective measurement point, and long‐term stability. An uncertainty budget was derived for relative and absolute dose measurements in photon and electron beams.

Results:

Exradin W1 showed a temperature dependence of −0.225% °C−1. The loss of sensitivity with accumulated dose decreased with use. The sensitivity of Exradin W1 was energy independent for high‐energy photon and electron beams. All remaining dependencies of Exradin W1 were around or below 0.5%, leading to an uncertainty budget of about 1%. When a dual channel electrometer with automatic trigger was not used, timing effects became significant, increasing uncertainties by one order of magnitude.

Conclusions:

The Exradin W1 response is energy independent for high energy x‐rays and electron beams, and only one calibration coefficient is needed. A temperature correction factor should be applied to keep uncertainties around 2% for absolute dose measurements and around 1% for relative measurements in high‐energy photon and electron beams. The Exradin W1 scintillator is an excellent alternative to detectors such as diodes for relative dose measurements.
Resource Letter TTSM-1: Teaching Thermodynamics and Statistical Mechanics in Introductory Physics, Chemistry, and Biology
Authors: Dreyfus Benjamin W. , Geller Benjamin D. , Meltzer David E. , Sawtelle Vashti
Published: December 2014

This Resource Letter draws on discipline-based education research from physics, chemistry, and biology to collect literature on the teaching of thermodynamics and statistical mechanics in the three disciplines. While the overlap among the disciplinary literatures is limited at present, we hope this Resource Letter will spark more interdisciplinary interaction.
Public Attitudes Toward People With Intellectual Disabilities After Viewing Olympic or Paralympic Performance
Authors: Ferrara Kate , Burns Jan , Mills Hayley
Published: December 2014

Despite some changes to the way that people with intellectual disabilities (ID) are viewed in society, negative attitudes prevail. One of the aspirations of the 2012 Paralympic games was to influence the public’s attitudes toward people with disabilities. The aim of this study was to investigate whether stimuli depicting people with ID performing at Paralympic level of competition change attitudes toward ID. A mixed randomized comparison design was employed comparing 2 groups: those who viewed Paralympic-level ID sport footage and information and those who viewed Olympic footage and information. One hundred fourteen students, mean age 25 yr, were administered measures of implicit (subconscious) attitudes toward disability and explicit (belief-based) attitudes toward ID. Implicit attitudes significantly changed in a positive direction for both groups. The findings provide evidence that both Paralympic (ID) and Olympic media coverage may have at least a short-term effect on attitudes toward people with disabilities.
Sialic Acid-Binding Protein
Sp
2CBMTD Protects Mice against Lethal Challenge with Emerging Influenza A (H7N9) Virus
Authors: Govorkova Elena A. , Baranovich Tatiana , Marathe Bindumadhav M. , Yang Lei , Taylor Margaret A. , Webster Robert G. , Taylor Garry L. , Connaris Helen
Published: December 2014

Compounds that target the cellular factors essential for influenza virus replication represent an innovative approach to antiviral therapy.
Sp
2CBMTD is a genetically engineered multivalent protein that masks sialic acid-containing cellular receptors on the respiratory epithelium, which are recognized by influenza viruses. Here, we evaluated the antiviral potential of
Sp
2CBMTD against lethal infection in mice with an emerging A/Anhui/1/2013 (H7N9) influenza virus and addressed the mechanistic basis of its activity
in vivo. Sp
2CBMTD was administered to mice intranasally as a single or repeated dose (0.1, 1, 10, or 100 μg) before (day −7, −3, and/or −1) or after (6 or 24 h) H7N9 virus inoculation. A single
Sp
2CBMTD dose (10 or 100 μg) protected 80% to 100% of the mice when administered 7 days before the H7N9 lethal challenge. Repeated
Sp
2CBMTD administration conferred the highest protection, resulting in 100% survival of the mice even at the lowest dose tested (0.1 μg). When treatment began 24 h after exposure to the H7N9 virus, a single administration of 100 μg of
Sp
2CBMTD protected 40% of the mice from death. The administration of
Sp
2CBMTD induced the pulmonary expression of proinflammatory mediators (interleukin-6 [IL-6], IL-1β, RANTES, monocyte chemotactic protein-1 [MCP-1], macrophage inflammatory protein-1α [MIP-1α], and inducible protein [IP-10]) and recruited neutrophils to the respiratory tract before H7N9 virus infection, which resulted in less pronounced inflammation and rapid virus clearance from mouse lungs.
Sp
2CBMTD administration did not affect the virus-specific adaptive immune response, which was sufficient to protect against reinfection with a higher dose of homologous H7N9 virus or heterologous H5N1 virus. Thus,
Sp
2CBMTD was effective in preventing H7N9 infections in a lethal mouse model and holds promise as a prophylaxis option against zoonotic influenza viruses.
Caprylic Acid and Glyceryl Trinitrate Combination for Eradication of Biofilm
Authors: Rosenblatt Joel , Reitzel Ruth A. , Raad Issam
Published: December 2014

There is a growing need for biocompatible, broad-spectrum, nonantibiotic, antimicrobial treatments because of the frequent ineffectiveness of antibiotics against biofilms and the increasing incidence of antibiotic resistance. In this study, we demonstrate rapid and complete biofilm eradication in an
in vitro
model with synergistic combinations of glyceryl trinitrate and caprylic acid against resistant Gram-positive, Gram-negative, and fungal biofilms.
Use and Clinical Interpretation of Pneumococcal Antibody Measurements in the Evaluation of Humoral Immune Function
Authors: Daly Thomas M. , Hill Harry R.
Published: December 2014

Pneumococcal vaccination is a commonly used technique for assessing the humoral immune status of a patient suspected of having immunodeficiency. Interpretation of what constitutes an adequate response, however, can be challenging. This is due to the complexity of the data generated from serotype-specific assays, historical variations in the assays used to measure pneumococcal antibodies, and varying recommendations on the relevant cut points that define response. In this review, we summarize the historical evolution of assays used for this purpose and discuss the analytical considerations that have influenced published data. We also examine current clinical recommendations for defining an adequate response to vaccination, with a particular focus on the interpretation of serotype-specific data generated by multiplex assays.
Human Adenovirus Type 7 Infection Associated with Severe and Fatal Acute Lower Respiratory Illness and Nosocomial Transmission
Authors: Cui Xianyan , Wen Liang , Wu Zhihao , Liu Nan , Yang Chaojie , Liu Wei , Ba Zhongwei , Wang Jian , Yi Shengjie , Li Hao , Liang Beibei , Li Peng , Jia Leili , Hao Rongzhang , Wang Ligui , Hua Yuejin , Wang Yong , Qiu Shaofu , Song Hongbin
Published: December 2014

A 23-year-old male died of severe pneumonia and respiratory failure in a tertiary hospital in Beijing, and 4 out of 55 close contacts developed fever. Molecular analysis confirmed human adenovirus type 7 (HAdV7) as the causative agent. We highlight the importance of early diagnosis and treatment and proper transmission control of HAdV7.
Structure of an Enteric Pathogen, Bovine Parvovirus
Authors: Kailasan Shweta , Halder Sujata , Gurda Brittney , Bladek Heather , Chipman Paul R. , McKenna Robert , Brown Kevin , Agbandje-McKenna Mavis
Published: December 2014

Bovine parvovirus (BPV), the causative agent of respiratory and gastrointestinal disease in cows, is the type member of the
Bocaparvovirus
genus of the
Parvoviridae
family. Toward efforts to obtain a template for the development of vaccines and small-molecule inhibitors for this pathogen, the structure of the BPV capsid, assembled from the major capsid viral protein 2 (VP2), was determined using X-ray crystallography as well as cryo-electron microscopy and three-dimensional image reconstruction (cryo-reconstruction) to 3.2- and 8.8-Å resolutions, respectively. The VP2 region ordered in the crystal structure, from residues 39 to 536, conserves the parvoviral eight-stranded jellyroll motif and an αA helix. The BPV capsid displays common parvovirus features: a channel at and depressions surrounding the 5-fold axes and protrusions surrounding the 3-fold axes. However, rather than a depression centered at the 2-fold axes, a raised surface loop divides this feature in BPV. Additional observed density in the capsid interior in the cryo-reconstructed map, compared to the crystal structure, is interpreted as 10 additional N-terminal residues, residues 29 to 38, that radially extend the channel under the 5-fold axis, as observed for human bocavirus 1 (HBoV1). Surface loops of various lengths and conformations extend from the core jellyroll motif of VP2. These loops confer the unique surface topology of the BPV capsid, making it strikingly different from HBoV1 as well as the type members of other
Parvovirinae
genera for which structures have been determined. For the type members, regions structurally analogous to those decorating the BPV capsid surface serve as determinants of receptor recognition, tissue and host tropism, pathogenicity, and antigenicity.

IMPORTANCE
Bovine parvovirus (BPV), identified in the 1960s in diarrheic calves, is the type member of the
Bocaparvovirus
genus of the nonenveloped, single-stranded DNA (ssDNA)
Parvoviridae
family. The recent isolation of human bocaparvoviruses from children with severe respiratory and gastrointestinal infections has generated interest in understanding the life cycle and pathogenesis of these emerging viruses. We have determined the high-resolution structure of the BPV capsid assembled from its predominant capsid protein VP2, known to be involved in a myriad of functions during host cell entry, pathogenesis, and antigenicity for other members of the
Parvovirinae
. Our results show the conservation of the core secondary structural elements and the location of the N-terminal residues for the known bocaparvovirus capsid structures. However, surface loops with high variability in sequence and conformation give BPV a unique capsid surface topology. Similar analogous regions in other
Parvovirinae
type members are important as determinants of receptor recognition, tissue and host tropism, pathogenicity, and antigenicity.
Tobacco smoking and risk of endometriosis: a systematic review and meta-analysis
Authors: Bravi Francesca , Parazzini Fabio , Cipriani Sonia , Chiaffarino Francesca , Ricci Elena , Chiantera Vito , Viganò Paola , La Vecchia Carlo
Published: December 2014

Objective

Since conflicting results have been published on the role of tobacco smoking on the risk of endometriosis, we provide an up-to-date summary quantification of this potential association.

Design

We performed a PubMed/MEDLINE search of the relevant publications up to September 2014, considering studies on humans published in English. We searched the reference list of the identified papers to find other relevant publications. Case–control as well as cohort studies have been included reporting risk estimates on the association between tobacco smoking and endometriosis. 38 of the 1758 screened papers met the inclusion criteria. The selected studies included a total of 13 129 women diagnosed with endometriosis.

Setting

Academic hospitals.

Main outcome measure

Risk of endometriosis in tobacco smokers.

Results

We obtained the summary estimates of the relative risk (RR) using the random effect model, and assessed the heterogeneity among studies using the χ2test and quantified it using the I2statistic. As compared to never-smokers, the summary RR were 0.96 (95% CI 0.86 to 1.08) for ever smokers, 0.95 (95% CI 0.81 to 1.11) for former smokers, 0.92 (95% CI 0.82 to 1.04) for current smokers, 0.87 (95% CI 0.70 to 1.07) for moderate smokers and 0.93 (95% CI 0.69 to 1.26) for heavy smokers.

Conclusions

The present meta-analysis provided no evidence for an association between tobacco smoking and the risk of endometriosis. The results were consistent considering ever, former, current, moderate and heavy smokers, and across type of endometriosis and study design.
Testing the performance of a spatially explicit tag-integrated stock assessment model of yellowtail flounder (Limanda ferruginea) through simulation analysis
Authors: Goethel Daniel R. , Legault Christopher M. , Cadrin Steven X.
Published: December 2014

In any stock assessment application, the implicit assumptions regarding spatial population structure must be carefully evaluated. Tag-integrated models offer a promising approach for incorporating spatial structure and movement patterns in stock assessments, but the complexity of the framework makes implementation challenging and the appraisal of performance difficult. A flounder-like fishery was simulated to emulate the metapopulation dynamics of the three yellowtail flounder (Limanda ferruginea) stocks off New England, and the robustness of spatially explicit tag-integrated models were compared with closed population assessments. Different movement parametrizations and data uncertainty scenarios were simulated, while the ability of the tag-integrated model to estimate reporting rate and time-varying movement were also evaluated. Results indicated that the tag-integrated framework was robust for the simulated fishery across a wide range of connectivity levels and that tag reporting rates were accurately estimated. Closed population models also demonstrated limited error. Therefore, spatially explicit approaches may not always be warranted even when regional connectivity is occurring, but tag-integrated models can provide improved parameter estimates when reliable tagging data are available. Tag-integrated models also serve as valuable tools for informing spatially explicit operating models, which can then be used to evaluate the assumptions and performance of closed population models.
Using salvage logging and tolerance to risk to reduce the impact of forest fires on timber supply calculations
Authors: Leduc A. , Bernier P.Y. , Mansuy N. , Raulier F. , Gauthier S. , Bergeron Y.
Published: December 2014

It is acknowledged that natural forest fires cannot and even should not be eliminated from the North American boreal forest. Forest fires produce immediate losses of wood volume, disrupt the conversion of the actual forest age structure into a target structure, and prevent planned timber supply (PTS) levels from being achieved. In this paper, we explore the extent to which periodic shortfalls in available timber under various burn rates can be mitigated through salvage logging and the tolerance of forest managers to a given level of shortfall, both as a function of forest age class structure. Simulations are done using both a deterministic and a stochastic representation of burn rate over time. Results show that the frequency of shortfall events can be reduced by salvage logging and by the introduction of measures that generate a tolerance to shortfall and that this mitigation potential is influenced by initial forest age class structure and burn rate. Results also show that even a 100% rate of salvage logging cannot fully compensate for timber losses to fire and eliminate fire-induced timber shortfalls. Furthermore, interannual burn rate variability reduces the efficiency of both mitigation measures. As the PTS is never realized under fire risk, the real cost of opting for different PTS scenarios should be estimated not from the difference in PTS but rather from the more realistic difference in realized timber harvest.