bluuebunny/crossref_metadata_2025 huggingface dataset:
The relation between neural and perceptual intensity: a comparative study on the neural and psychophysical response to taste stimuli
Authors: Borg G. , Diamant H. , Ström L. , Zotterman Y.
Published: December 2014

1. Recording the summated electrical response from the human chorda tympani in the middle ear provides data for a quantitative study of the relation between the neural activity and the strength of the stimulus applied to the tongue which can be compared with the relation between the subjective estimation and the stimulus strength.

2. Full comparative data obtained from two patients showed a very high correlation between the functions describing the subjective and the neural response in relation to the strength of citric acid and sucrose solutions applied to the tongue. In a third patient the same high correlation was obtained for NaCl and citric acid.

3. The good agreement between the individual neurophysiological experiments and the psychophysical group experiment favours the view that a fundamental congruity is found between neural activity and perceptual intensity.
The topology of dermatomal projection in the medial lemniscal system
Authors: Werner Gerhard , Whitsel Barry L.
Published: December 2014

1. The topographic organization of first order afferent fibres in the lumbar, sacral and coccygeal dorsal roots, and in the fasciculus gracilis was studied in squirrel monkeys.

2. At the entry zone, progressing from caudal to rostral, dorsal root filaments receive fibres from tail and hind‐limb receptive fields which serially overlap and describe a spiral‐shaped trajectory. The latter starts with tail, progresses post‐axially towards the foot, crosses the foot from lateral to medial, and ascends the preaxial leg.

3. In the fasciculus gracilis, this arrangement of fibres at the dorsal root entry zone is preserved in its entirety. It assumes the form of a fibre lamination, with the most caudal dorsal root fibres occupying a dorso‐medial location; further rostral dorsal root fibres come to lie more ventrolaterally.

4. Dorsum and sole of foot project in an overlapping and interdigitating manner to the fibre lamina of the 7th lumber dermatome in the fasciculus gracilis. Thereby, dorsum and sole of foot behave in the projection as if they were one and the same surface.

5. The argument is presented that the foot and its projection on to the cross‐sectional plane of the dorsal funiculus are topologically equivalent and that the hind‐limb as a whole and its projection are not. On the other hand, homotopic mapping of the foot together with the sequential fibre organization in the dorsal funiculus enable many more types of closed curves on the body surface to remain arc‐wise connected in the projection than would otherwise be possible.
The calcium content of the smooth muscle of the guinea‐pig taenia coli
Authors: Goodford P. J.
Published: December 2014

1. The in vitro calcium content of the smooth muscle of the guinea‐pig taenia coli was 3·0 m‐mole Ca/kg wet wt. when phosphate was omitted from the bathing medium, and was almost independent of pH changes in the range 6·7‐7·6.

2. The calcium content was not changed when 1 m
M phosphate was included in the medium, if the pH was 6·7 or 7·0. However, when the pH was 7·6, the calcium content increased by 1·5 m‐mole Ca/kg wet wt. in the presence of phosphate.

3. The calcium content rose by 1·1 m‐mole Ca/kg wet wt. when NaCl in the bathing medium was replaced by isotonic sucrose, and rose by 0·7 m‐mole Ca/kg wet wt. when MgCl2 in the bathing medium was replaced. These increases may reflect a competition between Ca2+ and other cations for fixed negative sites in the tissue.

4. The initial rapid phase of 42K exchange corresponded to an ‘extra‐cellular 42K‐space’ of 470 ml./kg fresh wt. in normal solution, rising to 560 ml./kg. fresh wt. in low‐sodium solution and to 760 ml./kg fresh wt. in calcium‐free low‐sodium solution. In this last medium the extra‐cellular [14C]sorbitol space was only 390 ml./kg fresh wt., so that there was a large excess of rapidly‐exchanging potassium which may have been competing at fixed negative sites.
Factors affecting the relative magnitudes of the sodium: potassium and sodium: sodium exchanges catalysed by the sodium pump
Authors: Garrahan P. J. , Glynn I. M.
Published: December 2014

1. The effects of external potassium on sodium: potassium exchange and sodium: sodium exchange in human red cells have been estimated from measurements of ouabain‐sensitive potassium influx and ouabain‐sensitive sodium influx in media containing different concentrations of potassium.

2. As the external potassium concentration is increased from zero to 5 m
M, sodium:sodium exchange—as judged by ouabain‐sensitive sodium influx—is progressively suppressed, and sodium:potassium exchange—as judged by ouabain‐sensitive potassium influx—is progressively increased. Both exchanges are half‐maximal between 1 and 2 m
M‐K, and at 5 m
M‐K sodium: sodium exchange becomes very small as sodium: potassium exchange approaches a maximum.

3. Experiments have been carried out, mainly on resealed ghosts, to determine what factors affect the magnitude of the sodium:sodium exchange in potassium‐free solutions.

4. Sodium:sodium exchange does not occur in the absence of adenosine triphosphate (ATP).

5. Ghosts containing high concentrations of sodium, no potassium and high concentrations of ATP show no ouabain‐sensitive loss of sodium into potassium‐free solutions. The ability to carry out sodium:sodium exchange can be restored by replacing most of the internal sodium with potassium or by preparing the cells so that they contain much more orthophosphate (Pi) than ATP.

6. Ghosts containing sodium in low concentration, potassium in high concentration and with a low [ATP]/([ADP].[Pi]) ratio show a greater ouabain‐sensitive loss of sodium into potassium‐free media than into media containing potassium; i.e. external potassium reduces ouabain‐sensitive sodium efflux.

7. The effect of Pi is not the result of competitive inhibition of the transport ATPase since Pi at the concentrations used does not inhibit ATPase activity in fragmented ghosts.
Some factors involved in the thalamic control of spontaneous barbiturate spindles
Authors: Andersen P. , Andersson S. A. , Lømo T.
Published: December 2014

1. The origin of thalamic and cortical spontaneous spindles was studied in cats anaesthetized with sodium pentobarbital.

2. Complete removal of all cortical grey matter left the thalamic rhythmic spindle activity unchanged.

3. Removal of the entire thalamus or pronounced oedema in the thalamus abolished completely the spindle activity in the corresponding hemisphere.

4. In a neuronally isolated cortical area, a fast, low voltage background activity appeared, interrupted by occasional irregular rapid potential changes (sharp waves) of high voltage. Regular spindle rhythms were seldom observed unless excited by a depolarizing drug. Spontaneous spindles did not invade the isolated cortex via a bridge of intact cortical tissue.

5. With increasingly larger destruction of the thalamus in a rostro‐caudal direction, the activity in the post‐cruciate cortex did not change until the anterior third of the thalamus was encroached upon. A transverse section in front of the thalamus nearly eliminated the cortical spindles.

6. Complete removal of the mid line and intralaminar nuclei left the spontaneous rhythmic activity of the lateral thalamic nuclei and of the frontal cortex principally unchanged.

7. Removal of the laterally located thalamic nuclei, including the n. ventralis posterolateralis (VPL), abolished virtually all spontaneous spindle activity of the frontal cortex, including the post‐cruciate area.

8. Local cortical cooling reduced the amplitude but not the frequency of the cortical spindles.

9. Cooling of the whole brain reduced both the amplitude and the frequency of the spindles. At low temperatures, all spindle activity in the cortex disappeared, and occasional sharp waves occurred, as with de‐afferentation.

10. It is concluded that the rhythm of the cortical spontaneous barbiturate spindles is generated exclusively by thalamic neurones. The electromotive force of the corticographic waves, however, has a cortical origin.
Dependence of the magnitude of the Stiles—Crawford effect on retinal location
Authors: Westheimer Gerald
Published: December 2014

1. The directional sensitivity (Stiles—Crawford effect) of retinal cones is supposed to be associated with their shape, but only extrafoveal cones have a cone‐like shape; cones in the central fovea are elongated and look like rods.

2. To determine whether the directional sensitivity of cones depends on their shape, the Stiles—Crawford effect was measured both in the central fovea and in the parafovea of the human eye.

2. To ensure that the cone population tested was homogeneous, a small brief test flash, brought into the eye through the centre of the pupil, was placed at threshold by varying the intensity of a large adapting field. The directional sensitivity of the cones was determined by finding the efficiency of light to act as an adapting background as a function of position of entry in the pupil.

4. Central foveal cones have a less pronounced directional sensitivity than parafoveal cones and this lends support to the conclusion that the Stiles—Crawford effect is connected with the shape of the retinal receptors.
Cortical acetylcholine release and electroencephalographic arousal
Authors: Szerb J. C.
Published: December 2014

1. In cats anaesthetized with N2O‐halothane acetylcholine (ACh) release from the parietal cortex was measured. In addition, low and high‐frequency electroencephalographic (e.e.g.) activity was recorded quantitatively.

2. Stimulation of the mesencephalic reticular formation at 30, 60 and 100/sec produced an identical increase in cortical ACh output, while 300/sec stimulation was about ⅓ as effective and 10/sec stimulation failed to increase ACh output.

3. Reticular formation stimulation at 60 and 100/sec reduced the low‐frequency and increased the high‐frequency e.e.g. activity. Stimulation at 30 and 300/sec was less effective, while 10/sec stimulation had no effect on e.e.g.

4. Acute undercutting of the cortex did not affect the resting output of ACh but greatly reduced the increase due to reticular formation stimulation as compared to the contralateral intact side. Cutting the cortex around the collection area did not affect the increase in ACh output due to reticular formation stimulation.

5. Stimulation of the hypothalamus, medial thalamus and septum at 100/sec also increased cortical ACh output while stimulation of the dorsal hippocampus and caudate nucleus failed to do so.

6. Low frequency cortical e.e.g. activity was reduced by stimulating the reticular formation, the hypothalamus, the medial thalamus and slightly by septum stimulation. High‐frequency e.e.g. activity was increased by stimulating the reticular formation and the hypothalamus.

7. It is concluded that the ACh measured originates from the neural tissue underlying the collection area. The increased release is concomitant to e.e.g. activation but the pathways involved in cortical e.e.g. activation and increased ACh release are distinct, since the two phenomena do not vary in a parallel fashion when the reticular formation is stimulated at different frequencies or when different subcortical areas are stimulated.

8. The effectiveness of septal stimulation in increasing ACh release indicates that at least part of the cortical cholinergic fibres traverse this area on their way to the cortex.
The innervation of the vas deferens of the guinea‐pig
Authors: Ferry C. B.
Published: December 2014

1. The compound action potential of the hypogastric nerve of the guinea‐pig contained two main elevations. The low‐threshold fibres had a range of conduction velocities from 1·5 to 10 m/sec. The high threshold fibres conducted action potentials at less than 1 m/sec. The hypogastric nerve contained small myelinated fibres and non‐myelinated fibres.

2. In the preparation in vitro, junctional potentials and contractions were elicited by stimulation of the rapidly conducting fibres alone. Trains of C fibre volleys were ineffective.

3. In the preparation in vivo, conduction from the hypogastric nerve to the vas deferens nerve was unidirectional and abolished by hexamethonium. After the administration of hexamethonium, the contraction produced by stimulation of the vas deferens nerve was unaffected.

4. The close arterial injection of acetylcholine (ACh) into the pelvic viscera caused centrifugal activity in the motor fibres of the vas deferens nerve, but no impulses were detected in the hypogastric nerve.

5. Ganglion cells are present in the last 2 cm of the hypogastric nerve.

6. It is concluded that there is a ganglionic relay between the hypogastric and vas deferens nerves.
Local and central circulatory responses to sustained contractions and the effect of free or restricted arterial inflow on post‐exercise hyperaemia
Authors: Lind A. R. , McNicol G. W.
Published: December 2014

1. The cardiovascular responses to sustained contractions at tensions from 5 to 30% maximal voluntary contraction (MVC) have been examined. At 5 and 10% MVC blood pressure, heart rate and forearm blood flow all reached a steady state during the contraction; post‐exercise hyperaemia did not show peak flows higher than those found during exercise. At tensions of 20 and 30% MVC, none of the measurements showed a steady state during the contractions, but increased steadily throughout the contraction; post‐exercise hyperaemia characteristically showed peak flows in excess of any flow measured during contractions. The results obtained at a tension of 15% MVC did not show a steady‐state during the contraction but the following hyperaemia showed a similar pattern to that seen at the lower tensions.

2. Digital compression of the brachial artery after sustained handgrip contractions for periods of 3 or 6 min after the contraction ended resulted in only a small reduction, on average by 5‐15%, of the post‐exercise hyperaemia.

3. Consideration of the evidence leads to the view that in physiological circumstances the post‐exercise hyperaemia following sustained contractions bears a close relationship to the metabolism of the active muscles.
Circulatory responses to sustained hand‐grip contractions performed during other exercise, both rhythmic and static
Authors: Lind A. R. , McNicol G. W.
Published: December 2014

1. The cardiovascular responses to sustained hand‐grip contractions at 20, 30 and 50% maximal voluntary contraction (MVC) were measured in subjects who were engaged in treadmill walking at three different rates with oxygen intakes of 1·1, 1·7 and 2·8l./min. The increments in heart rate and blood pressure at tensions of 20 and 30% MVC were similar at all rates of walking, but the response to a contraction at 50% MVC was lower at the hardest work rate than at the two easier rates.

2. When two or more muscle groups contracted at the same relative tension, the increments in heart rate and blood pressure were the same, whether they contracted separately or together.

3. When two or more muscle groups contracted simultaneously at different relative tensions, the increments in heart rate and blood pressure were the same as when the muscle group, at the higher relative tension, contracted separately at that tension.

4. The blood flow to a muscle engaged in sustained contraction was increased when a second muscle group contracted at a higher relative tension.
Athletes at altitude
Authors: Pugh L. G. C. E.
Published: December 2014

1. Six international middle‐distance runners were investigated during 4 weeks in England and during a similar period in Mexico City (2270 m (7450 ft.))

2. In 3‐mile (4828 m) time trials at 2270 m the increase in time taken by four subjects compared with sea level was 8·5% on the 4th day and 5·7% on the 29th day. There was thus a gain of 2·8% or 20 sec in time associated with acclimatization.

3. In 1‐mile (1609 m) time trials the times were increased by 3·6% in the first week at altitude and by 1·5% in the 4th week. The improvement amounted to 2·1%, or 4·9 sec.

4. In 5 min maximum exercise on the ergometer maximum O2 intake for six subjects at altitude was reduced by 14·6% on the 2nd day and 9·5% on the 27th. Only one subject showed no change in maximum oxygen intake (V̇O2, max) with time spent at altitude.

5. Although V̇O2, max was persistently reduced at altitude work rates finally exceeded sea‐level values, owing to increased over‐all efficiency.

6. Forty‐minute recovery O2 intakes after 5 min maximum exercise averaged 17·35 l. at sea level and 17·53 l. at altitude. Mean values from 40th to 50th min were within ± 7% of pre‐exercise values.

7. Serial tests at increasing loads yielded a straight‐line relation between O2 intake and work rate over a wide range of work rates at sea level and at altitude. Heart rate and ventilation for given work intensity were maximal in the first 2‐10 days at altitude and thereafter declined.

8. Capillary HbO2 saturation fell from 93% at rest to 87% in maximum exercise. The corresponding alveolar gas tensions were PA, O2 89 mm Hg, PA, CO2 24 mm Hg. About half the total unsaturation in maximum exercise was explained by the Bohr effect.

9. In six of eight pairs of determinations V̇O2, max measured on the ergometer was within ± 0·15 l./min of V̇O2, max measured on the running track. Nevertheless, it was not possible to predict running performance from ergometer measurements.
Ca‐coupling in the anterior byssal retractor muscle of Mytilus edulis L
Authors: Leenders H. J.
Published: December 2014

1. Experiments designed to elucidate the role of Ca in the excitation—contraction coupling of the anterior byssus retractor muscle (ABRM) were carried out. Ca influences membrane depolarization and provides for coupling of the contraction in response to repetitive electrical stimulation as well as of ACh and KCl contracture. Depriving ABRM of Ca results in two closely correlated events: disappearance of action potential and of the contraction in response to repetitive electrical stimulation.

2. A sigmoid increase in tension with the log‐Ca concentration in artificial medium was observed whereas, over the same range of concentrations, the tension remnant decreased.

3. Induction of relaxation by 5‐HT is Ca dependent. Either thiourea inactivation or Ca deprivation results in failure to relax. Low concentrations of 5‐HT (10−7 g/ml.) bring about increase in peak tension of the contraction in response to repetitive electrical stimulation, whereas higher concentrations (10−5 g/ml.) undermine peak tension.

4. Frequencies exceeding 40 cycles evoke a contraction accompanied by tension remnant, which is eliminated with 5‐HT.

5. Dropwise addition of Ca on a trypsin window in the muscle induces a latency relaxation before onset of Ca‐contracture.
A study of cholinoceptive cells in the lateral geniculate nucleus
Authors: Phillis J. W. , Tebēcis A. K. , York D. H.
Published: December 2014

1. The dorsal lateral geniculate nucleus (LGN) of the cat stains densely for acetylcholinesterase, which is present in intra‐axonal and extracellular locations.

2. Acetylcholine (ACh), cholinomimetic drugs, anticholinesterases and ACh antagonists were administered iontophoretically to neurones in the LGN.

3. ACh excited eighty‐six of 184 (46·7%) geniculate neurones and depressed seven (3·8%).

4. The excitatory response to ACh was frequently larger than that to
L‐glutamate and had a comparable time course.

5. There was a considerable variation in the proportion of ACh sensitive cells in different animals. ACh firing was facilitated by optic nerve or visual stimulation.

6. Carbamylcholine was the most active of the choline esters tested, frequently exceeding ACh in potency. The other choline esters and nicotine were consistently less active than ACh.

7. Anticholinesterases, eserine, neostigmine and edrophonium potentiated the action of ACh, and often caused excitation. Eserine caused an initial small enhancement in the amplitude of the focal potential evoked by optic nerve stimulation followed by a reduction in amplitude and prolongation of duration of the potential.

8. Atropine and benzoquinonium effectively prevented the ACh excitation of many cells. Dihydro‐β‐erythroidine failed to cause a significant reduction in the magnitude of the ACh response. All three ACh antagonists failed to reduce the excitant effects of optic nerve or visual stimulation.

9. Stimulation of the mesencephalic reticular formation caused either an enhancement or a reduction in the excitability of ACh sensitive neurones in the LGN. Benzoquinonium abolished the excitatory effects of reticular formation stimulation.

10. The findings presented in this paper suggest that ACh is the transmitter released by terminals of nerves of the reticular formation projection to the LGN.
The effects of light‐adaptation on rod and cone receptive field organization of monkey ganglion cells
Authors: Gouras Peter
Published: December 2014

1. Receptive fields of perifoveal ganglion cells have been measured by determining threshold for eliciting a just detectable response using either concentric spot stimuli centred on the receptive field or small spot stimuli in different parts of the receptive field at various states of retinal adaptation and with stimuli selected to separate rod from cone function.

2. Light‐adaptation decreases the sensitivity, latency and duration of threshold responses throughout the receptive field of a ganglion cell.

3. With all patterns of retinal stimulation and states of adaptation, threshold signals of the rods reach a ganglion cell later and those of the cones earlier than approximately 50 msec after a light stimulus.

4. In the more dark‐adapted retina threshold rod and cone signals can be transmitted to the brain by the same or by neighbouring ganglion cells but not simultaneously; in the light‐adapted state only the cone signal is transmitted.
A combined method for demonstrating the cholinesterase activity and the nervous structure of mammalian peripheral motor endings in teased preparations
Authors: Ip M. C.
Published: December 2014

Both the neural and subneural components of mammalian peripheral motor endings in teased preparations have been shown by a new method which combines a silver method with a cholinesterase technique. The significant application of this method to the study of the motor terminals is suggested.
Temperature changes produced by the injection of catecholamines and 5‐hydroxytryptamine into the cerebral ventricles of the conscious mouse
Authors: Brittain R. T. , Handley S. L.
Published: December 2014

1. Changes in temperature were determined following injection of noradrenaline, adrenaline, isoprenaline, dopamine and 5‐hydroxytryptamine (5‐HT) into the cerebral ventricles of the conscious mouse.

2. Noradrenaline (1‐20 μg) and dopamine (10‐160 μg) caused falls in body temperature. Adrenaline (1‐20 μg) caused a slight and transient rise in body temperature followed by a fall. Isoprenaline (5‐20 μg) caused a rise in body temperature, hypothermia only occurring after very high doses (200 μg) of this catecholamine.

3. α‐ and β‐adrenergic blocking agents, phentolamine (> 2 μg) and propranolol (> 5 μg) respectively, caused falls in body temperature when injected into the cerebral ventricles of the mouse.

4. Specific drug antagonism studies were limited owing to the intrinsic effects of the α‐ and β‐adrenergic blocking agents. However, some evidence was obtained to indicate that noradrenaline mediated its effects through a central α‐type adrenergic receptor.

5. 5‐HT (10‐160 μg) caused a fall in body temperature. The action of this indoleamine and the catecholamines in regard to thermoregulatory function is discussed.
5‐Hydroxytryptamine participation in the vagal inhibitory innervation of the stomach
Authors: Bülbring Edith , Gershon M. D.
Published: December 2014

1. Intraluminal pressure was recorded from the isolated guinea‐pig and mouse stomach with the vagus and sympathetic nerves attached.

2. The response to vagal stimulation, which consists of an excitatory and an inhibitory component, resembled the response to 5‐hydroxytryptamine (5‐HT), which has no direct action on the muscle but acts on intrinsic excitatory and inhibitory ganglia.

3. In the presence of hyoscine, the effect of vagal stimulation, of nicotinic compounds and of 5‐HT were all purely relaxant. Competitive block of ganglionic receptors for acetylcholine reduced the vagal relaxation without antagonizing 5‐HT. Specific desensitization of ganglionic receptors for 5‐HT reduced the vagal relaxation without antagonizing nicotinic compounds.

4. During the early phase of the blocking action of nicotine, responses to vagal stimulation and to 5‐HT were both abolished. As the non‐specific antagonism changed to the later phase of specific antagonism to acetylcholine, the inhibitory (but not the excitatory) component of the vagal response recovered partially, in parallel with the recovery of the relaxant effect of 5‐HT.

5. The vagal inhibitory effect was completely abolished only when competitive block of acetylcholine receptors was combined with desensitization of 5‐HT receptors.

6. Stimulation of the mouse stomach (after asphyxiation of the mucosa and exclusion of the luminal content) in the presence of hyoscine caused the release of 5‐HT; this release was blocked by tetrodotoxin.

7. The results, together with previous observations that 5‐HT is contained within preganglionic nerve fibres in the myenteric plexus, are consistent with the hypothesis that 5‐HT, with acetylcholine, may be a neurotransmitter in the vagal inhibitory innervation of the stomach.
Properties of motor units in fast and slow skeletal muscles of the rat
Authors: Close R.
Published: December 2014

1. Three kinds of motor unit have been distinguished in soleus (SOL) and extensor digitorum longus (EDL) muscles of adult rats on the basis of differences in isometric twitch contraction times measured at 35° C.

2. SOL contains about thirty motor units of which about twenty‐seven are slow and three are intermediate with average contraction times of 38 and 18 msec respectively.

3. EDL contains about forty fast motor units with an average contraction time of 11 msec.

4. Average values for maximum isometric tetanic tension were 4·7 g for fast and slow units and 5·85 g for intermediate units.

5. Average values for twitch‐tetanus ratios ranged from 0·2 to 0·227 for EDL muscles, SOL muscles and the three kinds of motor units.
The effect of stress on the concentration of 3β‐hydroxypregn‐5‐en‐20‐one (pregnenolone) and pregn‐4‐ene‐3,20‐dione (progesterone) in the adrenal gland of the rat
Authors: Holzbauer Margarethe , Newport Helen M.
Published: December 2014

1. Pregnenolone and progesterone were estimated in extracts from adrenal glands of rats by gas—liquid chromatography.

2. In unstressed rats their concentrations were found to be smaller than that of corticosterone.

3. Acute stress caused an increase in the concentrations of these steroids which paralleled that of corticosterone.
Oxygen consumption by the isolated smooth muscle of guinea‐pig taenia coli
Authors: Bülbring Edith , Golenhofen K.
Published: December 2014

1. An apparatus is described for simultaneous measurement of oxygen consumption and electrical and mechanical activity of isolated smooth muscle preparations.

2. The mean oxygen uptake by the isolated taenia coli of the guinea‐pig was 10‐20 μl./g/min.

3. In spontaneously active preparations, adrenaline (10−8‐10−7 g/ml.) caused, with the inhibition of electrical and mechanical activity, a reduction in oxygen uptake.

4. After prolonged exposure to substrate free solution spontaneous activity ceased periodically. Adrenaline, when applied during a silent period, had no detectable effect on resting oxygen consumption, while readmission of substrate, either glucose or β‐hydroxybutyrate, increased oxygen uptake.

5. Adrenaline did not modify the increased oxygen uptake during the initial recovery period when it was given simultaneously with the substrate. However, adrenaline shortened the time interval which elapsed from the addition of substrate until spontaneous activity was resumed, indicating an acceleration of the recovery process.
The relationship of the sphincter of Oddi to the stomach, duodenum and gall‐bladder
Authors: Wyatt A. P.
Published: December 2014

Flow through the sphincter of Oddi was studied by a constant‐pressure perfusion apparatus, and by using a constant rate of infusion and measuring pressure changes just proximal to the sphincter. Pressure changes from balloons placed in the gastric antrum and duodenum were recorded. Despite considerable variation in activity and behaviour, the following conclusions were reached.

1. The sphincter of Oddi appears to be partially autonomous but is readily affected by changes in duodenal tone.

2. Reflex inhibition of the sphincter of Oddi is seen on electrical and mechanical stimulation of the gall‐bladder but not with passive pressure changes within the gall‐bladder.

3. This reflex is relayed through the coeliac ganglion.

4. There is a definite relationship between gastric antral activity and flow through the sphincter of Oddi. This is more obvious when food is present in the stomach.

5. Mechanical or electrical stimulation of the stomach, duodenum, or upper small bowel influences the tone of the sphincter of Oddi.
Responses of skin blood vessels to bradykinin, histamine and 5‐hydroxytryptamine
Authors: Greaves Malcolm , Shuster Sam
Published: December 2014

1. The responses of human cutaneous blood vessels to intradermal injection of bradykinin, histamine and 5‐hydroxytryptamine (serotonin) are studied in order to evaluate the ability of these agents to mediate the vascular changes of sustained acute inflammation in the skin.

2. Bradykinin produces erythema, owing to a direct effect on blood vessels, and wealing. Dose—response studies indicate that bradykinin is more potent than serotonin or histamine in respect of wealing.

3. The response to serotonin differs qualitatively as well as quantitatively according to dose. High doses cause wealing and erythema with the characteristics of an axon reflex flare, but low doses produce erythema by a local effect without wealing.

4. Using the technique of arterial occlusion, the occurrence of tachyphylaxis in respect of wealing was demonstrated with histamine and serotonin, but not with bradykinin. This evidence suggests that of the three agents, only bradykinin can mediate increased vascular permeability in sustained acute inflammation.

5. The specificity of tachyphylaxis and the failure of anti‐histamine to antagonize bradykinin wealing suggest that bradykinin and histamine act on separate blood vessel receptors.

6. Corticosteroids do not inhibit wealing due to a wide range of doses of bradykinin. The anti‐inflammatory activity of corticosteroids may therefore be due to reduced formation of kinins.
Cortical actions on hypoglossal motoneurones in cats: a proposed role for a common internuncial cell
Authors: Porter R.
Published: December 2014

1. Intracellular records were made of the synaptic potentials produced in hypoglossal motoneurones when electrical stimuli were applied to the cat's motor cortex.

2. The depolarizing synaptic responses reached their maxima in steps similar to those produced in the same motoneurones by suprathreshold stimulation of the lingual nerve.

3. Interneurones in or near the spinal trigeminal nucleus were caused to discharge by cortical shocks adequate to produce synaptic potentials in hypoglossal motoneurones. The latencies and patterns of repetitive responses in these interneurones were consistent with their possible role as internuncial cells in the motor pathway from cerebral cortex to hypoglossal motoneurones.

4. Individual interneurones in or near the spinal trigeminal nucleus could be caused to discharge both by stimulation of the lingual nerve and by stimulation of the motor cortex. This convergence suggests a common function for the internuncial cell in reflexly and cortically induced excitation of hypoglossal motoneurones and would allow the internuncial cell to be a site for integration of spatially separated excitatory influences.
Co‐operative action of calcium ions in transmitter release at the neuromuscular junction
Authors: Dodge F. A. , Rahamimoff R.
Published: December 2014

1. The quantitative dependence of transmitter release on external calcium concentration has been studied at the frog neuromuscular junction, using intracellular recording and taking the amplitude of the end‐plate potential (e.p.p.) as an index of the number of packets released.

2. The relation between [Ca] and the e.p.p. is highly non‐linear. The initial part of this relation on double logarithmic co‐ordinates gives a straight line with a slope of nearly four (mean 3·78 ± 0·2
S.D. in 28 experiments). Addition of a constant amount of Mg reduces the e.p.p. without altering the slope of the log e.p.p./log Ca relation.

3. The slope of this logarithmic relation diminishes as [Ca] is raised towards the normal level.

4. The results are explained quantitatively on the hypothesis that Ca ions combine with a specific site X on the nerve terminal forming CaX, and that the number of packets of acetylcholine released is proportional to the fourth power of [CaX].

5. The analysis suggests that a co‐operative action of about four calcium ions is necessary for the release of each quantal packet of transmitter by the nerve impulse.
An examination of certain factors which might, or do, affect the vascular response to oxytocin
Authors: Lloyd Sybil , Pickford Mary
Published: December 2014

1. A number of different observations were made on anaesthetized rats and some dogs to try to discover why it is that oxytocin is a vasodilator in dioestrus and anoestrus, and develops constrictor properties in oestrus and following sympathectomy.

2. In those circumstances in which oxytocin in small or moderate doses raises blood pressure in the rat, the pressor effect is eliminated if the hormone is given during an infusion of adrenaline. In this respect the rat is closely similar to the dog.

3. It was confirmed in anaesthetized oestrous rats that intravenous eserine eliminated the pressor response to oxytocin, and it was found that prostigmine did not reduce or change it. Thus, it may be concluded that the effect of eserine depends on its central sympathetic stimulant action and not on a peripheral effect.

4. Rats which had been acutely or chronically adrenalectomized responded normally to oxytocin and both eserine and adrenaline were able to reduce, though not wholly eliminate, the pressor type of response. These results indicate that neither the adrenal medulla nor the cortex is essential for the action of oxytocin, nor for a large part of the action of eserine and adrenaline.

5. The plasma concentrations of sodium, potassium and calcium were studied in a number of conditions affecting the response to oxytocin, namely, dioestrus, oestrus, and after administration of oestrogens, progesterone, adrenaline, eserine, hexamethonium, and dihydroergotamine. The cation changes observed could not be correlated with the type of response to oxytocin. The only measure found to affect the response was raising the plasma Na concentration by the infusion of disodium hydrogen phosphate. This reduced the pressor effect of oxytocin seen in oestrous female rats and in oestrogen treated males. The pressor response returned before the plasma sodium had fallen to normal levels.

6. The administration of the oxytocin analogue, tyrosine‐methyl2 oxytocin which has a high receptor affinity and a low intrinsic activity, prevented the pressor response to oxytocin of oestrous rats, and the vasodilator response in the hind limb vessels of normal dogs. It is concluded that there is probably a single receptor for oxytocin from which both the constrictor and dilator effects are initiated.

7. Oxytocin exerted apparently normal effects on the systemic blood pressure of oestrous or dioestrous rats given the β‐blocking agents pronethalol or propranolol.

8. The present results, like previous ones, indicate that adrenaline is the factor linking both the gonadal state and the peripheral sympathetic nervous system with the type of response to oxytocin.

9. An incidental observation was that male and female rats show differences in their response to sympathetic blocking agents and to a raised plasma sodium concentration.
The effect of ouabain on the secretion of catecholamines and on the intracellular concentration of potassium
Authors: Banks P.
Published: December 2014

1. Perfusion of bovine adrenal glands with 0.1 m
M ouabain is accompanied by a doubling of the spontaneous rate of release of catecholamines and by a 66% increase in the response to stimulation with carbamylcholine.

2. Perfusion with ouabain (0.1 m
M) reduces the intracellular content of potassium from 106 to 63 m
M.

3. The effect of ouabain on catecholamine secretion is dependent upon the presence of Ca2+ ions in contrast to the effect upon the potassium content which is not dependent upon the presence of calcium.

4. Ouabain has no effect on the release of catecholamines from isolated chromaffin granules both in the presence and absence of Ca2+ ions.

5. A possible relationship between the secretion of catecholamines and the concentration gradient of potassium across the cell membrane is discussed.
Effects of salt loading and haemodilution on the responses of perfused cat kidneys to angiotensin
Authors: Lockett Mary F.
Published: December 2014

1. Effects of single intra‐arterial injections (0.1‐1.0 μg) of angiotensin II have been observed on cat kidneys perfused with heparinized blood from heart—lung circuits.

2. Angiotensin II always caused an abrupt decrease in renal plasma flow (R.P.F.) which reached maximum in 1–2 min and lasted over‐all for only 3.5‐4.0 min. Glomerular filtration rate (G.F.R.) usually and filtration fraction (F.F.) always increased.

3. Angiotensin II caused antidiuresis provided that the kidney had not been subjected either to salt loading or to haemodilution within the preceding 3 hr. These pretreatments converted the antidiuretic action of angiotensin into a diuresis.

4. Angiotensin II raised the rate of Na excretion, the urinary concentration of Na and the urinary Na/K whether anti‐diuretic or diuretic.
Effects of changes in PO2 and PCO2 and pH on the total vascular resistance of perfused cat kidneys
Authors: Lockett Mary F.
Published: December 2014

1. The effects of change in arterial PO2, PCO2 and pH on the total vascular resistance (RVR) of the perfused cat kidney have been separately measured and expressed as ± percentage deviations from control values.

2. Control levels in arterial blood were pH 7.38, P−O2 160 mm Hg, in equilibrium with 5% CO2.

3. Increase in PO2 alone, in excess of 220 mm Hg, raised RVR reversibly reading 108% control levels at a PO2 280 mm Hg (P = < 0.001).

4. High levels of PO2 favoured the onset of ‘outflow block’, which was characterized by irreversible increase in RVR accompanied by rise in plasma filtration fraction (F.F.) and in the extraction ratio for p‐aminohippuric acid (PAH extraction).

5. Reduction in PO2 to 80 mm Hg decreased RVR by 4% (P = < 0.001).

6. RVR was not significantly affected by pH changes within the range 7.25‐7.45. Lowering arterial pH to 7.15 raised RVR by 4% (P = < 0.001) reversibly. Increase in arterial pH to 7.56 raised RVR by 6% (P = < 0.001) reversibly.

7. Changes in arterial PCO2 produced large inverse reversible changes in RVR. Halving PCO2 raised RVR by 18%; doubling PCO2 decreased RVR by 25%.

8. Changes in RVR caused by alteration of arterial pH or PCO2 were not accompanied by changes either in F.F. or in PAH extraction.
A Gas Turbine Dynamic Model for Simulation and Control
Authors: Perez-Blanco Horacio , Henricks Todd B.
Published: December 2014

The useful life of gas turbines and the availability of power after start-up depend on their transient response. For this reason, several articles have been written on the dynamic simulation of gas turbine systems in electrical generation, cogeneration, and marine applications. The simulations typically rely on performance maps and time lags extracted from manufacturer’s specifications. This work was undertaken to increase the generality of turbine models over what can be obtained from performance maps. The paper describes a mathematical computer model developed to investigate the dynamic response of a simple single-shaft gas turbine system. The model uses design parameters normally incorporated in gas turbine design (e.g. load coefficient, flow coefficient, and deHaller Number) as well as compressor and turbine stage geometry and compressor and turbine material properties. A dynamic combustion chamber model is also incorporated. Other input parameters are included to enable the model to be adaptable to various system sizes and environments.

The model was formulated in a graphical interface, and the results of several trials are displayed. The influence of important parameters (e.g. fuel-air ratio, IGVs, load, efficiencies) on turbine response from a “cold” start and from steady-state is studied. To gain further insights into the response, a start-up procedure similar to that reported in the literature for an industrial gas turbine system is simulated. Because of the approach used, the computer model is easily adaptable to further improvements and combined simulation of turbines and control systems.
Combining Bayesian Belief Networks With Gas Path Analysis for Test Cell Diagnostics and Overhaul
Authors: Palmer Carl A.
Published: December 2014

Engine overhaul shops need a reliable analytical methodology to pinpoint the cause(s) of engine test-cell under-performance to aid the overhaul decision-making process. Gas path analysis codes have been somewhat successful, but have not been entirely satisfactory. Previous works [Doel, 1994] have raised the idea that if other information could be integrated with the gas path analysis results, it may be possible to achieve better results.

This paper presents a diagnostic system developed for the CF6 family of engines. The system integrates test cell measurements and the gas path analysis program results with information regarding engine operational history, build-up workscope, and direct physical observations in a Bayesian belief network. The paper lays out the nature of the problem and the system requirements and design.

The system produces a diagnosis while following a cost-effective diagnostic process using value of information calculations. This is illustrated through sample cases.
Comparative Thermoeconomic Analysis Between Combined Cycle Units Derived From Existing Steam Power Plants and a New Combined Cycle Plant
Authors: Negri di Montenegro G. , Peretto A. , Mantino E.
Published: December 2014

In this paper, a thermoeconomic analysis is carried out for two and three pressure level combined cycles derived from existing steam power plants. The considered steam power plants are among the most widespread in the Italian territory (70 MW, 160 MW, 320 MW power output).

First of all, the gas turbine plants that best match the steam power plants’ requirements are selected among existing units.

Subsequently, the thermodynamic analysis for the repowered plants is performed, taking into account the off-design working condition of some components such as, the steam turbines and the condenser.

Then, the economic evaluation for the repowered plants is carried out by determining the cost per kWh, the pay back period and the internal rate of return. The analysis permits the most economic choice to be made.

The thermoeconomic investigation was also performed for a new combined cycle power plant.

The study has revealed that the repowering of the three existing steam power plants in two or three pressure level combined cycle plants is more convenient than building a new combined cycle with higher efficiency.

It has also pointed out that the repowering of the 320 MW existing steam power plant in a three pressure level reheat combined cycle plant supplies the lowest cost per kWh among all the other repowered plants analyzed.

The revamping and environment effect on the above mentioned existing steam power plants was also investigated and it resulted that this solution has a cost per kWh that is much higher than that of the repowered steam plants and the new combined cycle.
Investigation of Unsteady Flow Phenomena in a Counterrotating Ducted Propfan
Authors: Wallscheid L. , Eulitz F. , Heinecke R.
Published: December 2014

Experimental and numerical investigations on a counterrotating propfan (CRISP) have been carried out to study unsteady flow phenomena generated by the interaction of the two rotors. This paper focuses mainly on the downstream effects of rotor 1 on rotor 2. Therefore unsteady Laser-2-Focus, unsteady total pressure measurements and an unsteady simulation have been carried out. The total pressure measurements behind the rotors show variations of the absolute total pressure outside the wake regions up to 30 percent of the average total pressure rise. Some of these are caused by the interaction of the rotor 1-generated wakes with the leading edge of rotor 2. The others may result from the pressure waves generated by the reflection of the rotor 2-shockwaves by the blades of rotor 1.
The Effect of Inlet Boundary Layer Thickness on the Flow Within an Annular S-Shaped Duct
Authors: Sonoda Toyotaka , Arima Toshiyuki , Oana Mineyasu
Published: December 2014

Experimental and numerical investigations were carried out to gain a better understanding of the flow characteristics within an annular S-shaped duct, including the effect of the inlet boundary layer (IBL) on the flow. A duct with six struts and the same geometry as that used to connect compressor spools on our experimental small two-spool turbofan engine was investigated. A curved downstream annular passage with a similar meridional flow path geometry to that of the centrifugal compressor has been fitted at the exit of S-shaped duct. Two types of the IBL (i.e. thin and thick IBL) were used.

Results showed that large differences of flow pattern were observed at the S-Shaped duct exit between two types of the IBL, though the value of “net” total pressure loss has not been remarkably changed. According to “overall” total pressure loss, which includes the IBL loss, the total pressure loss was greatly increased near the hub as compared to that for a thin one. For the thick IBL, a vortex pair related to the hub-side horseshoe vortex and the separated flow found at the strut trailing edge has been clearly captured in the form of the total pressure loss contours and secondary flow vectors, experimentally and numerically. The high-pressure loss regions on either side of the strut wake near the hub may act on a downstream compressor as a large inlet distortion, and strongly affect the downstream compressor performance. There is a much-distorted three-dimensional flow pattern at the exit of S-Shaped duct. This means that the aerodynamic sensitivity of S-Shaped duct to the IBL thickness is very high. Therefore, sufficient carefulness is needed to design not only downstream aerodynamic component (for example centrifugal impeller) but also upstream aerodynamic component (LPC OGV).