bluuebunny/crossref_metadata_2025_split huggingface dataset:
PERMEABILITY OF CANINE SUBMANDIBULAR GLANDS TO BLOOD‐BORNE HORSERADISH PEROXIDASE DURING PARASYMPATHETIC SECRETION
Authors: Garrett J. R. , Klinger A. H. , Parsons P. A. 
Published: December 2014

Potential permeability pathways exist between central acinar cells in submandibular glands of dogs and they are large enough to allow the passage of molecules of horseradish peroxidase (HRP) under certain conditions.During gentle submandibular secretion caused by parasympathetic nerve stimulation detectable amounts of HRP passed into the saliva as long as the concentration of HRP in the blood reaching the gland was high enough. Morphological results indicated that the passage was mainly via leaky junctions between acinar cells. It is likely that this movement was by passive permeation because it required a high concentration gradient, was slow to occur and gradually reached a peak; the actual amounts to reach the saliva under physiological conditions were small and depended on the effective concentration of HRP reaching the gland.A satisfactory reproducible secretory regime has been developed, using short periods of stimulation alternating with rest pauses. Using these conditions gradually increasing amounts of HRP reached the saliva and first samples of saliva during each stimulation period contained more HRP than subsequent samples from the same stimulation period. It is possible that contraction of myoepithelial cells, at the outset of each stimulation period, contributed to this increased movement by acting on HRP‐containing fluid in spaces between themselves and the acinar cells, thereby causing an increased filtration pressure to be exerted on underlying tight junctions.
MEASUREMENTS OF ENDOMETRIAL BLOOD FLOW IN ANAESTHETIZED EWES BY XENON‐133 CLEARANCE AND MICROSPHERE TECHNIQUES
Authors: Fraser I. S. , Brown B. W. , Mattner P. E. , Hutton B. F. 
Published: December 2014

In six anaesthetized, non‐pregnant ewes, uterine blood flow rates measured by monitoring the clearance of xenon (133Xe) from the lumen of the uterus were compared with estimates of endometrial and myometrial capillary blood flow obtained by the use of microspheres of 15 µm diameter (eleven comparisons).On analysis, seven of the 133Xe clearance curves indicated the occurrence of both a fast and a slow compartment of flow with flow rates approximating to the rate of capillary blood flow in the caruncular and inter‐caruncular portions of the endometrium, respectively. In each of the remaining four curves which provided a single estimate of flow, the derived blood flow rate was similar to the rate of capillary blood flow in both the caruncular and inter‐caruncular portions of the endometrium. No relationship existed between myometrial capillary blood flow and the flow rates derived from the 133Xe clearance curves.
APPLICATION OF HIGH PERFORMANCE LIQUID CHROMATOGRAPHY TO STUDY TRANSPORT AND METABOLISM OF NUCLEIC ACID DERIVATIVES BY RAT JEJUNUM IN VITRO: ENDOGENOUS WASHOUT
Authors: Parsons D. S. , Shaw M. I. 
Published: December 2014

Quarterly Journal of Experimental Physiology 68–1 (1983)On page 40 paragraph 7 should readEnzymes were purine nucleoside phosphorylase (PNP) (E.C. 2.4.2.1.), uricase (E.C. 1.7.3.3.), hexokinase (E.C. 2.7.1.1.), glucose‐6‐phosphate dehydrogenase (E.C.1.1.1.49.), alanine dehydrogenase (E.C.1.4.1.1.), glutamate dehydrogenase (E.C.1.4.1.3.) all from Boehringer, and xanthine oxidase (XOD) (E.C.1.3.2.) from Sigma.
MOUSE MUTANTS AS MODELS IN ENDOCRINE RESEARCH
Authors: Charlton H. M. 
Published: December 2014

Although Shire (1979) has listed some forty‐eight mouse mutants of interest to the endocrinologist, this short review has concentrated upon eleven mutations which have resulted in a significant number of scientific publications over the last 4 or 5 years. The selection of references has had to be limited, but it should be possible easily to expand the list given in this review.Although the proximate cause of none of the eleven mutations has been identified with certainty, the abnormalities of function have included hormone deficiencies and receptor and post‐receptor malfunctions.It is perhaps a reflexion on our society in the 1980s, that the bulk of research has concentrated on the obese mouse. However, we still do not know the initial cause of this syndrome.The major disadvantage of the mouse to the hormone assayist lies in the small blood volume and the extreme difficulty in taking serial blood samples over a short period of time. With increased sophistication of assay techniques this may prove less daunting, but is an area where a review of the literature reveals discrepancies between laboratories, and even between data generated by the same laboratory at different times. With regard to the hormone content of endocrine tissues, the way forward for peptide‐secreting glands may be in the measurement of mRNA levels for particular hormones. Certainly the methods of recombinant‐DNA technology will yield positive information upon the aetiology and expression of some of the syndromes considered above.Organ transplantation is an area in which mutant mice have proved useful, for example gonadal, pituitary and pancreatic tissue transplantation. The grafting of neural tissue in the hpg mouse has added a further dimension to this field of research.The great infrastructure of genetical research in mice has enabled us to breed mutant genes onto different genetic backgrounds. This area of research is one which deserves to expand. The techniues of in vitro fertilization, chimera formation and embryo transfer have been used, in part, in studies on mouse mutants, and should provide technical means for further investigating gene expression.The family of dwarf mutants are ideally suited for research into the expression of genes micro‐injected into the fertilized egg (see Charlton & Cox, 1983).As new hormones are isolated and become available for study these mouse mutants may well be useful in delineating physiological functions for natural and pharmacological products. Again, the dwarf mutants would seem ideally suited for research into the synthesis and action of GRF.Mouse mutants have proved of use to biochemists and embryologists and provide fertile ground for endocrine investigations ranging from molecular genetics to membrane biophysics.
Afterload‐induced left ventricular diastolic dysfunction during myocardial ischaemia and reperfusion
Authors: Diakos Nikolaos A. , Pozios Iraklis , Katsaros Lampros , Vakrou Styliani , Sventzouri Stefania , Michelinakis Nikolaos , Tseliou Eleni , Bonios Michael , Malliaras Konstantinos , Papalois Apostolos , Anastasiou‐Nana Maria , Terrovitis John V. 
Published: December 2014

New Findings

What is the central question of this study?
While the load dependence of the diastolic function is established for the normal heart, little is known about the response of the acutely ischaemic and reperfused myocardium to alterations in afterload.

What is the main finding and its importance?
Using a model that simulates the clinical scenario of acute ischaemia–reperfusion, we show that increased afterload aggravates diastolic dysfunction during both acute ischaemia and reperfusion. In addition, increased afterload induces diastolic dyssynchrony, which might be the underlying mechanism of the diastolic dysfunction of the ischaemic myocardium. These findings provide us with new information regarding how better to manage patients who undergo revascularization therapy after acute myocardial infarction.

The effects of changes in left ventricular (LV) afterload on diastolic function of acutely ischaemic and reperfused myocardium have not been studied in depth. We examined the following factors: (i) the consequences of increasing the LV afterload on LV diastolic function during acute ischaemia and reperfusion; (ii) whether the myocardial response to afterload elevation is stable throughout a 2 h reperfusion period; and (iii) the role of LV wall synchrony in the development of afterload‐induced diastolic dysfunction. We instrumented 12 anaesthetized, open‐chest pigs with Millar pressure catheters and piezoelectric crystals before ligating mid‐left anterior descending coronary artery for 1 h, followed by reperfusion for 2 h. Six of the animals survived throughout the 2 h of reperfusion, and their data were used for comparisons across the different experimental phases. Left ventricular afterload was increased by inflating an intra‐aortic balloon. Data were recorded at baseline, after 20 min of coronary occlusion and at 30 and 90 min of myocardial reperfusion. The increased afterload for 2 min lengthened the isovolumic relaxation during ischaemia and during early and late reperfusion but had no significant effect on isovolumic relaxation before coronary artery occlusion. Increasing the afterload aggravated LV diastolic dyssynchrony during coronary artery occlusion, but not during reperfusion. The afterload‐induced prolongation of isovolumic relaxation was positively correlated with afterload‐induced diastolic dyssynchrony. These observations indicate that, during myocardial ischaemia and throughout reperfusion, LV diastolic function is afterload dependent. Afterload‐induced diastolic dyssynchrony might be an underlying mechanism of diastolic dysfunction during acute ischaemia.
Environomic Optimization for Combined Plants Including CO2 Influence
Authors: Santarelli M. , Borchiellini R. , Massardo A. F. 
Published: December 2014

In the paper two environomic procedures for the analysis and the optimization of energy systems, where environmental considerations are taken into account together with thermodynamic and economic ones, are presented. The aim is the assignment to energy plants of costs linked to their pollutant activities. The problem is faced with two different environomic approaches: (a) a method assigning a cost to the pollutant emissions (environmental cost); (b) a method assigning a cost to the exergy destroyed inside the system and rejected in the biosphere with the plant wastes (efficiency penalty).
As an example the environomic analysis is developed considering the pollutant emissions (CO, NOx and SOx) of an existing 700 MW combined power plant. Finally, a procedure to determine an efficiency penalty to the emitted CO2 is presented, and a comparison is developed between the results obtained by the two environomic approaches.
Exergy Analysis of Combined Cycles Using Latest Generation Gas Turbines
Authors: Facchini Bruno , Fiaschi Daniele , Manfrida Giampaolo 
Published: December 2014

The potential performance of optimized gas-steam combined cycles built around latest-generation gas turbine engines is analyzed, by means of energy/exergy balances.
The options here considered are the reheat gas turbine and the H-series with closed-loop steam blade cooling. Simulations of performance were run using a well-tested Modular Code developed at the Department of Energy Engineering of Florence and subsequently improved to include the calculation of exergy destruction of all types (heat transfer, friction, mixing and chemical irreversibilities). The blade cooling process is analyzed in detail as it is recognized to be of capita] importance for performance optimization.
The distributions of the relative exergy destruction for the two solutions — both capable of achieving energy/exergy efficiencies in the range of 60% — are compared and the potential for improvement is discussed.
Actively Controlled Bearing Dampers for Aircraft Engine Applications
Authors: Vance John M. , Ying Daniel , Nikolajsen Jorgen L. 
Published: December 2014

This paper describes some of the requirements for bearing dampers to be used in an aircraft engine and briefly discusses the pros and cons of various types of dampers that were considered as candidates for active control in aircraft engines. A disk type of electrorheological (ER) damper was chosen for further study and testing. The paper explains how and why the choice was made. For evaluating potential applications to aircraft engines, an experimental development engine (XTE-45) was used as an example for this study.
Like most real aircraft engines, the XTE-45 ran through more than one critical speed in its operating speed range. There are some speeds where damping is desirable and other speeds where it is not. Thus, the concept of a damper with controllable forces appears attractive. The desired equivalent viscous damping at the critical speeds along with the available size envelope were two of the major criteria used for comparing the dampers.
Most previous investigators have considered the ER damper to produce a purely Coulomb type of damping force and this was the assumption used by the present authors in this study. It is shown in a companion paper (Vance and San Andres, 1999), however, that a purely Coulomb type of friction cannot restrain the peak vibration amplitudes at rotordynamic critical speeds and that the equivalent viscous damping for rotordynamics is different from the value derived by previous investigators for planar vibration. Control laws for Coulomb damping are derived in Vance and San Andres, (1999) to achieve minimum rotor vibration amplitudes in a test rig while avoiding large bearing forces over a speed range that includes a critical speed. The type of control scheme required and its effectiveness was another criterion used for comparing the dampers in this paper.
Dynamic Coefficients of Stepped Labyrinth Gas Seals
Authors: Kwanka K. 
Published: December 2014

Rotor-fluid interactions can cause self-excited shaft vibrations of high density turbomachinery. Often the amplitude of the vibrations reaches unacceptably high amplitudes and the scheduled power or running speed cannot be achieved. One of the most important sources of excitation is the flow through labyrinth seals. For a reliable design it is necessary to predict these forces exactly, including not only stiffness but also damping coefficients.
As the forces in labyrinth gas seals are rather small only minimal experimental data is available for the comparison and validation of calculations. Meanwhile a new and easy-to-handle identification procedure enables the investigation of numerous seal geometrys. The paper presents dynamic coefficients obtained with a stepped labyrinth and the comparison with other seal concepts.
Full-Annulus Simulations of Airfoil Clocking in a 1-1/2 Stage Axial Compressor
Authors: Dorney D. J. , Sondak D. L. , Cizmas P. G. A. , Saren V. E. , Savin N. M. 
Published: December 2014

Axial compressors have inherently unsteady flow fields because of relative motion between rotor and stator airfoils. This relative motion leads to viscous and inviscid (potential) interactions between blade rows. As the number of stages increases in a turbomachine, the buildup of convected wakes can lead to progressively more complex wake/wake and wake/airfoil interactions. Variations in the relative circumferential positions of stators or rotors can change these interactions, leading to different unsteady forcing functions on airfoils and different compressor efficiencies. In addition, as the Mach number increases the interaction between blade rows can be intensified due to potential effects.
It has been shown, both experimentally and computationally, that airfoil clocking can be used to improve the efficiency and reduce the unsteadiness in multiple-stage axial turbomachines with equal blade counts in alternate blade rows. While previous investigations have provided an improved understanding of the physics associated with airfoil clocking, more research is needed to determine if airfoil clocking is viable for use in modern gas-turbine compressors. This paper presents the results of a combined experimental/computational research effort to study the physics of airfoil clocking in a high-speed axial compressor. Computational simulations have been performed for eight different clocking positions of the stator airfoils in a 1-1/2 stage high-speed compressor. To accurately model the experimental compressor, full-annulus simulations were conducted using 34 IGV, 35 rotor and 34 stator airfoils. It is common practice to modify blade counts to reduce the computational work required to perform turbomachinery simulations, and this approximation has been made in all computational clocking studies performed to date. A simulation was also performed in the present study with 1 inlet guide vane, 1 rotor airfoil, and 1 stator airfoil to model blade rows with 34 airfoils each in order to examine the effects of this approximation. Time-averaged and unsteady data (including performance and boundary layer quantities) were examined. The predicted results indicate that simulating the full annulus gives better qualitative agreement with the experimental data, as well as more accurately modeling the interaction between adjacent blade rows.
Realizability in Turbulence Modelling for Turbomachinery CFD
Authors: Moore Joan G. , Moore John 
Published: December 2014

It is obvious that the Reynolds normal stresses uu¯ should always be positive in all directions, i.e. the computed turbulence stresses should be realizable. However, the commonly used two-equation turbulence models do not incorporate realizability. They take the turbulent viscosity as cμk2/ε with cμ a constant, and frequently generate negative normal stresses far from walls in the nominally inviscid sections of turbomachinery flows. Pressure gradients due to leading edge stagnation and blade turning create an inviscid strain field. These strains cause the calculation of negative normal stresses over significant portions of the flow field. The result can be erroneous increases in turbulence kinetic energy upstream of the leading edge by a factor of ten or more. This erroneous turbulence is then convected around the blade and through the blade row, significantly affecting the computed boundary layer development and profile losses.
Frequently the problem of overproduction is avoided by using artificially high values of the dissipation, ε, at the inlet. But this incorrect procedure is not needed when realizability is incorporated in the turbulence model.
The paper reviews some methods and models which ensure realizability in two-equation turbulence models. The extent of the problem and its solution are illustrated with examples from compressor and turbine cascades.
Passive Control of Combustion Instability in Lean Premixed Combustors
Authors: Steele Robert C. , Cowell Luke H. , Cannon Steven M. , Smith Clifford E. 
Published: December 2014

A Solar fuel injector that provides lean premixed combustion conditions has been studied in a combined experimental and numerical investigation. Lean premixed conditions can be accompanied by excessive combustion driven pressure oscillations which must be eliminated before the release of a final combustor design. In order to eliminate the pressure oscillations the location of fuel injection was parametrically evaluated to determine a stable configuration. It was observed that small axial changes in the position of the fuel spokes within the premix duct of the fuel injector had a significant positive effect on decoupling the excitation of the natural acoustic modes of the combustion system.
In order to further understand the phenomenon, a time-accurate 2D CFD analysis was performed. 2D analysis was first calibrated using 3D steady-state CFD computations of the premixer in order to model the radial distribution of velocities in the pre mixer caused by non-uniform inlet conditions and swirling flow. 2D time-accurate calculations were then performed on the baseline configuration. The calculations captured the coupling of heat release with the combustor acoustics, which resulted in excessive pressure oscillations. When the axial location of the fuel injection was moved, the CFD analysis accurately captured the fuel time lag to the flame-front, and qualitatively matched the experimental findings.
Validation of the Booster Bleed Valve Control Logic in the New BR715 Jet Engine
Authors: Peitsch Dieter , Fiola Roland , Brodmuehler Rene , Nielsen Annette 
Published: December 2014

The subject of this paper is the validation of the newly developed booster bleed valve control logic, which has been implemented into the new BR715 turbo fan jet engine.
The booster compressor is protected from surges in the low power regime as well as during transient operation by opening a booster bleed valve. This bleed valve is situated just after the booster compressor and passes bleed air into the bypass duct, hence unloading the booster compressor in critical operational conditions. The BR715 jet engine takes advantage of a newly developed logic driving this valve. Monitoring input parameters such as spool and flight speeds as well as altitude, the combined steady state and transient logic provides the capability of appropriately positioning the valve. This ensures maintaining an optimum performance of the engine throughout the whole operating range. Furthermore the logic allows for reaction on special requirements such as surge events.
During testing for certification of this engine, extensive handling tests have been performed. The performance of the logic was investigated in detail and the results are documented within this paper. They prove the logic to be working very successfully. The booster compressor is totally protected from surge in the low power regime during steady state conditions. For transient operation, especially during rapid decelerations as well as during bodie manoeuvres of the engine, the core logic for the transient modulation showed extremely effective behaviour.
The various schedules inside the logic were partially varied for testing. This paper comprises this development process and each table’s contribution to the booster compressor’s behaviour is explained in detail.
Emergence of Recuperated Gas Turbines for Power Generation
Authors: McDonald Colin F. 
Published: December 2014

In the emerging deployment of microturbines (25–75Kw), a recuperator is mandatory to achieve thermal efficiencies of 30 percent and higher, this being important if they are to successfully penentrate the market currently dominated by Diesel generator sets. This will be the first application of gas turbines for electrical power generation, where recuperators will be used in significant quantities. The experience gained with these machines will give users’ confidence that recuperated engines will meet performance and reliability goals. The latter point is particularly important, since recuperated gas turbines have not been widely deployed for power generation, and early variants were a disappointment. Recuperator technology transfer to larger engines will see the introduction of advanced heat exchanged industrial gas turbines for power generation in the 3–15 Mw range.
After many decades of development, existing recuperators of both primary surface and plate-fin types, have demonstrated acceptable thermal performance and integrity in the cyclic gas turbine environment, but their capital costs are high.
A near-term challenge to recuperator design and manufacturing engineers is to establish lower cost metallic heat exchangers that can be manufactured using high volume production methods. A longer term goal will be the development and utilization of a ceramic recuperator, since this is the key component to realize the full performance potential of very small and medium size gas turbines.