bluuebunny/crossref_metadata_2025_split huggingface dataset:
Depositional system and palaeoclimatic interpretations of Middle to Late Pleistocene travertines: Kocabaş, Denizli, south‐west Turkey
Authors: Toker Ezher , Kayseri‐Özer Mine Sezgül , Özkul Mehmet , Kele Sándor 
Published: December 2014

AbstractTravertine deposits in western Turkey are very well‐exposed in the area of Kocabaş, in the eastern part of the Denizli Basin. The palaeoclimatic significance of these travertines is discussed using U/Th dates, stable isotope data and palynological evidence. The Kocabaş travertine occurrences are characterized by successions of depositional terraces associated with palaeosols and karstic features. The travertines have been classified into eight lithotypes and one erosional horizon, namely: laminated, coated bubble, reed, paper‐thin raft, intraclasts, micritic travertine with gastropods, extra‐formational pebbles and a palaeosol layer. The analysed travertines mostly formed between 181 ka and 80 ka (Middle to Late Pleistocene) during a series of climatic changes including glacial and interglacial intervals; their δ13C and δ18O values indicate that the depositional waters were mainly of basinal thermal origin, occasionally mixed with surficial meteoric water. Palynological results obtained from the palaeosols showed an abundance of non‐arboreal percentage and xerophytic plants (Oleaceae and Quercus evergreen type) indicating that a drought occurred. Marine Isotope Stage 6 is represented by grassland species but Marine Isotope Stage 5 is represented by Pinaceae–Pinus and Abies, Quercus and Oleaceae. Uranium/thorium analyses of the Kocabaş travertines show that deposition began in Marine Isotope Stage 6 (glacial) and continued to Marine Isotope Stage 4 (glacial), but mostly occurred in Marine Isotope Stage 5 (interglacial). The travertine deposition continued to ca 80 ka in the south‐west of the study area, in one particular depression depositional system. Palaeoenvironmental indicators suggest that the travertine depositional evolution was probably controlled by fault‐related movements that influenced groundwater flow. Good correlation of the stable isotope values and dates of deposition of the travertines and palynological data of palaeosols in the Kocabaş travertines serve as a starting point for further palaeoclimate studies in south‐west Turkey. Additionally, the study can be compared with other regional palaeoclimate archives.
Postthaw characterization of umbilical cord blood: markers of storage lesion
Authors: Hubel Allison , Spindler Ralf , Curtsinger Julie M. , Lindgren Bruce , Wiederoder Sara , McKenna David H. 
Published: December 2014

BackgroundThe continued growth in the uses of umbilical cord blood (UCB) will require the development of meaningful postthaw quality assays. This study examines both conventional and new measures for assessing UCB quality after long‐term storage.Study Design and MethodsThe first arm of the study involved thawing UCB in storage for short (approx. 1 year) and long periods of time (>11 years). Conventional postthaw measures (colony‐forming units [CFU], total nucleated cell counts, CD34+45+) were quantified in addition to apoptosis. The second arm of the study involved taking units stored in liquid nitrogen and imposing a storage lesion by storing the units in −80°C for various periods of time. After storage lesion, the units were thawed and assessed.ResultsIn the first arm of the study, there was little difference in the postthaw measures between UCB stored for short and long periods of time. There was a slight increase in the percentage of CD34+45+ cells with time in storage and a reduction in the number of cells expressing apoptosis markers. When moved from liquid nitrogen to −80°C storage, the nucleated cell count varied little but there was a distinct decrease in frequency of CFUs and increase in percentage of cells expressing both early and late markers of apoptosis.ConclusionNucleated cell counts do not reflect damage to hematopoietic progenitors during long‐term storage. Expression of caspases and other markers of apoptosis provide an early biomarker of damage during storage, which is consistent with other measures such as CFU and percentage of CD34+45+ cells.
Steroid production and membrane potential measurement in cells of the adrenal cortex
Authors: Matthews E. K. , Saffran M. 
Published: December 2014

1. The relation between corticosteroid production and the cellular membrane potential of adrenocortical cells has been investigated using a flow system for the incubation in vitro of adrenal glands from neonatal rabbits. Corticosteroid production by the adrenal cells was determined by a fluorescence method; membrane potentials were measured with glass micro‐electrodes.2. Adrenocorticotrophic hormone (ACTH) increased corticosteroid production without altering the membrane potential of the adrenocortical cells. Conversely, a 5‐fold increase in [K]o did not increase corticosteroid production but decreased the cellular membrane potential. The increase in [K]o did not impair the stimulation of corticosteroid production by ACTH.3. The log dose—response relation between the concentration of ACTH in the incubation medium and the amount of corticosteroid produced by the adrenal tissue was linear.4. No evidence was found of a direct relation between the production of corticosteroid by adrenocortical cells and the cellular membrane potential. Indeed, the output of steroid appeared to be relatively independent of the polarization of the cell membrane.
Hyperpyruvaturia in experimental diabetes
Authors: Anderson J. , Coulson R. , Tomlinson R. W. S. 
Published: December 2014

1. The 24 hourly excretion of pyruvate and glucose has been measured in alloxan‐diabetic rats.2. The animals were allowed a 6‐day control period before being injected with alloxan (
I.V. 50 mg/kg body weight). The diabetes was treated by daily injections of insulin for a period of 6 days from the 7th to the 12th day following the alloxan injection.3. The pyruvate excretion increased more than 5‐fold following the induction of diabetes, the values being 189 ± 130 (
S.D.) μg/24 hr in the control period rising to an average of 1002 ± 664 (
S.D.) μg/24 hr over the first 6 days of diabetes. The administration of insulin over the second 6‐day period of diabetes caused the pyruvate excretion to decrease—though not significantly. Upon the withdrawal of the insulin treatment the pyruvate excretion increased significantly from 785 ± 315 (
S.D.) μg/24 hr to 2105 ± 679 (
S.D.) μg/24 hr, measured over a 5‐day period. The final period of pyruvate excretion was significantly greater than the excretion over the first diabetic period.4. The glucose excretion during the initial diabetic period was 6·75 ± 2·64 (
S.D.) g/24 hr. The administration of insulin caused a 42% decrease in glucose excretion compared to a decrease of 22% for the pyruvate. The withdrawal of insulin caused the glucose excretion to increase by 149% while the pyruvate excretion increased by 157%.5. Diabetes was also induced temporarily by injections of anti‐insulin serum and diazoxide. In each case significant glycosuria and hyperpyruvaturia were produced.6. The possible causes of the hyperpyruvaturia in diabetes are discussed.
Monoamines and their metabolites in the avian brain
Authors: Juorio A. V. , Vogt Marthe 
Published: December 2014

1. In the avian brain, a high concentration of dopamine was found in a sharply contoured region of the nucleus basalis which may or may not have included the nucleus entopeduncularis, and therefore lay within the palaeostriatum of the nomenclature of Crosby and Huber. This was thus the only region which may be considered biochemically homologous to the mammalian corpus striatum. For purposes of macroscopic identification only, the region is described here as the ‘anterior part of the nucleus basalis’. The concentration of dopamine was 3 μg/g in the pigeon, about the same in the duck and chicken, and 7·5 μg/g in the finch. In the pigeon this region also contained some noradrenaline; the quantity of 5‐hydroxytryptamine (1·4 μg/g) and 5‐hydroxyindolylacetic acid (0·6 μg/g) was larger than in any other part of the brain.2. In the brain of the pigeon and the chicken, the highest concentrations of noradrenaline (1·5 and 1·4 μg/g) were found in the hypothalamus.3. The concentration of adrenaline was higher in the avian than in the mammalian brain. In the hypothalamus, it ranged from 0·4 μg/g in the pigeon to 1 μg/g in the chicken.4. Fluorescence microscopy, using the formaldehyde condensation method, showed, in the anterior part of the nucleus basalis, a large area of diffuse green‐yellow fluorescence, similar in appearance to the fluorescence of the striatum of the rat. In addition this part of the brain contained a small region of fluorescent fibres and varicosities. It is suggested that the diffuse fluorescence was produced by dopamine. It was absent from brains of reserpine‐treated pigeons.5. In the pigeon, reserpine, tetrabenazine and prenylamine produced a decrease in the concentration of brain monoamines, an effect which was comparable to that seen in mammals. Yet, none of these drugs raised the concentration of homovanillic acid, but they increased that of 5‐hydroxyindolylacetic acid; these drugs raise the concentration of both acids in mammalian brain.6. In the pigeon β‐tetrahydronaphthylamine decreased the concentration of all monoamines and their metabolites, an action quite different from that produced in the mammalian brain.7. The main effect of morphine and of M 99 (6,14‐endoetheno‐7‐(2‐hydroxy‐2‐pentyl)‐tetrahydro‐oripavine hydrochloride) was a lowering of the noradrenaline concentration.8. As in mammals, chlorpromazine affected only the dopamine metabolism.9. In the guinea‐pig and the pigeon, the administration of α‐methyl‐DOPA led to a substitution of much of the cerebral noradrenaline by α‐methyl‐noradrenaline, sometimes in excess of the lost noradrenaline. However, although the loss of dopamine was severe in both pigeon and guinea‐pig, only little α‐methyl‐dopamine accumulated in the pigeon brain, so that it did not consitute a replacement for the lost dopamine; in the guinea‐pig, α‐methyl‐dopamine was found in quantities similar to, or exceeding those, of the lost dopamine.
The nature of rise in threshold produced by contrast‐flashes
Authors: Alpern M. , Rushton W. A. H. 
Published: December 2014

1. The rod threshold for seeing a flash on a 2½° square is raised by a nearly simultaneous flash that falls on the surround. When this ‘contrast‐flash’ is held fixed in intensity, it raises the log test threshold by a fixed amount no matter how far that threshold has already been raised by light adaptation owing to background or bleaching.2. This is surprising since fixed backgrounds and bleachings raise the log test threshold much more when the eye is dark than when light adapted.3. When the test flash is held at some fixed supra‐threshold value, the contrast flash exhibits a ‘critical level’, above which the test will no longer be seen. If the surround region upon which the contrast‐flash falls is adapted by background or bleaching, its efficacy is reduced so that the ‘critical level’ is raised.4. Surround adaptation raises the log ‘critical level’ by the same amount that it raises the log threshold for seeing the contrast‐flash itself.5. The way that contrast flashes raise the test threshold is thus entirely different from the way that adaptations by bleachings or backgrounds do. Contrast‐flash signals appear to inhibit test‐flash signals by interaction at some point central to the site where adaptation occurs.6. This permits the effect of adaptation on signals to be measured. A given state of adaptation attenuates all flash signals in the same proportion. And in any state of adaptation a single flash will reach threshold when the attenuated signal has a fixed size.
The timing of calcium action during neuromuscular transmission
Authors: Katz B. , Miledi R. 
Published: December 2014

1. When a nerve—muscle preparation is paralysed by tetrodotoxin, brief depolarizing pulses applied to a motor nerve ending cause packets of acetylcholine to be released and evoke end‐plate potentials (e.p.p.s), provided calcium ions are present in the extracellular fluid.2. By ionophoretic discharge from a 1
M‐CaCl2 pipette, it is possible to produce a sudden increase in the local calcium concentration at the myoneural junction, at varying times before or after the depolarizing pulse.3. A brief application of calcium facilitates transmitter release if it occurs immediately before the depolarizing pulse. If the calcium pulse is applied a little later, during the period of the synaptic delay, it is ineffective.4. It is concluded that the utilization of external calcium ions at the neuromuscular junction is restricted to a brief period which barely outlasts the depolarization of the nerve ending, and which precedes the transmitter release itself.5. The suppressing effect of magnesium on transmitter release was studied by a similar method, with ionophoretic discharges from a 1
M‐MgCl2‐filled pipette. The results, though not quite as clear as with calcium, indicate that Mg pulses also are only effective if they precede the depolarizing pulses.
Observations on carotid body chemoreceptor activity and cervical sympathetic discharge in the cat
Authors: Biscoe T. J. , Purves M. J. 
Published: December 2014

1. Parallel recordings have been made of the cervical sympathetic and carotid body chemoreceptor activity in the anaesthetized cat.2. The sympathetic activity remains remarkably constant while the chemoreceptor activity is varied by changes in the blood gas tensions of relatively short duration.3. Changes in intrathoracic pressure by obstruction to the airway or thoracic compression were associated with changes in the activity of both nerves.4. It is likely that, under normal conditions, the sympathetic nervous activity provides a stable vasomotor tone within the carotid body.
The active transport of fluorescein by the retinal vessels and the retina
Authors: Cunha-Vaz J. G. , Maurice D. M. 
Published: December 2014

1. The movement of fluorescein across the retinal surface of the rabbit's eye was estimated by measuring the concentration gradient of the dye in the vitreous body. These measurements were made in vivo by means of a slit‐lamp fluorophotometer, or were taken from frozen sections of enucleated eyes.2. In the normal eye, fluorescein does not pass from the blood to the vitreous body across any part of the retina. When injected into the vitreous body it passes rapidly out across the entire retinal surface, even against a very large concentration gradient.3. A variety of metabolic and competitive inhibitors, effective in blocking organic anion transport in the kidney and liver, tend to abolish this unidirectional movement of fluorescein across the retina.4. The region occupied by the retinal vessels is more sensitive to inhibition than other areas of the retina. Occlusion of the vessels by diathermy prevents the exchange of fluorescein in this region.5. It appears, then, that there is an active transport of organic anions out of the vitreous body, both by the retinal capillaries and by the retina itself. The latter system is probably located in the pigment epithelium and seems to be carried forward to the rear surface of the iris.6. Since the walls of the retinal vessels of the rabbit are freely in contact with the vitreous body, the active transport must take place across the capillary endothelial cells themselves. These vessels have structural and permeability characteristics found only in the central nervous system and it is to be presumed that the anion transport system is shared by the capillaries of the brain.7. The function of the transport in the retina may be to protect the nervous tissue from toxic materials by preventing their entry from the blood or by removing products of metabolism conjugated as organic anions. Alternatively, the mechanism may be concerned in maintaining the normal adhesion of the retina to the choroid, since retinal detachment was observed to follow its total inhibition.
Disuse in the lateral geniculate nucleus of the cat
Authors: Burke W. , Hayhow W. R. 
Published: December 2014

1. An attempt has been made to produce disuse in the lateral geniculate nucleus (LGN) of the cat, in the synapses between the optic nerve fibres and the principal cells of the nucleus. Evidence is produced that destruction of the visual receptor cells by iodoacetate or 1,5‐di(p‐aminophenoxy) pentane dihydrochloride effectively silences the optic nerve discharge and so achieves this result.2. Disuse of the LGN synapses does not cause any decrease in synaptic efficiency. The LGN response to a single stimulus to the optic nerve was not appreciably altered, and the depression which normally follows single or repeated stimuli was much reduced or absent. This increased responsiveness was unaffected by prolonged tetanization of the optic nerve during the experiment.3. Two possible explanations of the increased responsiveness are suggested: a post‐synaptic ‘decentralization’‐hypersensitivity and an increased output of transmitter per impulse. The relevance of these results to theories of learning is discussed.4. The LGN response of adult cats kept in complete darkness for periods of up to 966 days was not appreciably different from that in the normal cat and there was little or no increased responsiveness. This suggests that many retinal ganglion cells continue to discharge in total darkness for long periods. There is a possibility that disuse may develop after a long time in the dark.
Early effects of abrupt reduction of local pressure on the forearm and its circulation
Authors: Caro C. G. , Foley T. H. , Sudlow M. F. 
Published: December 2014

1. The pressure at the surface of a segment of forearm enclosed in a plethysmograph was abruptly reduced from atmospheric to ‐20 to ‐120 mm Hg.2. Forearm circumference (equivalent to the volume of a small segment of forearm (Vf)) was measured with a strain gauge. Pressure was measured in the plethysmograph (Pp), in veins exposed (Pve) and not exposed (Pvne) to suction, in the brachial artery not exposed to suction (Pbane) and in forearm tissue (Pt).3. Reduction of Pp caused increase of Vf. This was not due to gas evolution, since bubbles would not be liberated at the pressures employed. Nor was increase of Vf due to venous backflow since Pve fell, but Pvne did not, even with upper arm circulation occluded or when Pvne was raised by venous occlusion prior to reduction of Pp.4. Reduction of Pp temporarily arrested venous outflow since Pve < Pvne < Pbane for 30 sec. With reduction of Pp 30 sec after occlusion of the upper‐arm circulation, Pve < Pvne for > 1 min, indicating that arterial inflow was then minimal.5. Increase of Vf, following reduction of Pp, was therefore due to inflow of arterial blood, of soft tissue or interstitial fluid. Interstitial fluid could flow from regions external to the plethysmograph, or enter as the result of filtration across capillaries. Occlusion of the upper arm circulation was not expected to interfere with motion of forearm soft tissue or the intratissue flow of interstitial fluid. It appears that capillary filtration is small compared with observed blood flow. Therefore subtraction of Vfoccl measured at intervals after reduction of Pp (upper arm circulation occluded) from Vf similarly obtained (but upper arm circulation free) appeared to give change of forearm volume due to inflow of arterial blood (ΔVb). V̇b, the volume inflow rate of arterial blood during suction, was then obtained.6. Resting forearm flow was 1·8 ml./min/100 ml. in seven normal subjects (average mean arterial blood pressure 86 mm Hg). With Pp = ‐90 mm Hg, V̇b was 10·2 ml./min/100 ml. Suction therefore reduced vascular resistance, measured as (Pbane—Pve) /V̇b.
The ontogeny of electrical activity associated with absorption of solutes across the developing small intestine of the chick (Gallus domesticus)
Authors: Hudson D. A. , Levin R. J. 
Published: December 2014

1. Electrical potentials across the developing intestine of the chick were measured in vitro 3‐4 days before and up to 32 days after hatching.2. Embryonic intestine had a very high endogenous p.d. (serosa positive to mucosa) which decreased up to hatching. This decrease continued during intestinal maturation, reaching a basal level several days after hatching.3. Transfer potential differences were caused only by the actively transferred hexoses both in embryonic and post‐embryonic intestine. These potentials decreased concomitantly with the decrease in the endogenous p.d. Kinetic analysis showed that the ‘apparent Km’ of glucose for the glucose transfer p.d. generating mechanism did not change over the period of hatching.4. Both the embryonic and post‐embryonic transmural p.d. either in the presence or absence of metabolizable hexose was dependent upon aerobic metabolism.5. The transmural p.d. of hatched chick small intestine (with and without hexoses) was linearly related to log10[Na+] of the mucosal fluid. The magnitude of the glucose transfer p.d. both in embryonic and post‐embryonic small intestine, however, was not lowered by decreasing the mucosal [Na+].6. Amino acid transfer potentials were of small magnitude at all stages of development.
Kinins, beta‐adrenergic receptors and functional vasodilatation in the submaxillary gland of the cat
Authors: Skinner N. Sheldon , Webster Marion E. 
Published: December 2014

1. The close arterial infusion of bradykinin into the submaxillary gland of the cat produced a pronounced hyperaemia that could be blocked by simultaneous perfusion of the gland with blood containing carboxypeptidase B. Carboxypeptidase B, however, failed to reduce the vasodilatation of chorda tympani nerve stimulation suggesting that the kinins are not involved in the regulation of submaxillary gland blood flow.2. Isoproterenol injections produced pronounced salivary gland vasodilatation. Beta‐adrenergic blocking drugs reduced or abolished the hyperaemia of isoproterenol and reduced that of chorda tympani nerve stimulation. The combination of beta‐blocking drugs and atropine could abolish or reduce further this nerve induced hyperaemia.3. The above results suggest that stimulation of cholinergic and beta‐adrenergic receptors could account for the chorda tympani induced hyperaemia. Conclusive proof of this possibility remains to be determined.
The role of plasma kinin in functional vasodilatation in the pancreas
Authors: Hilton S. M. , Jones Muriel 
Published: December 2014

1. Freshly collected pancreatic juice of the cat contained active kinin‐forming enzyme (kallikrein) and, in addition, an active kininase.2. In response to successive doses of secretin, the kinin‐forming activity of pancreatic juice fell off considerably. It was restored by pancreozymin.3. Stimulation of the dorsal vagus nerve caused an increase in venous outflow from the pancreas which was greater and more consistently seen when the splanchnic nerves had been sectioned.4. Intravenous injection of highly purified secretin usually had no effect on the outflow, whereas pancreozymin increased it up to 5 times.5. When the pancreas was perfused with oxygenated Locke solution, the effluent contained some kinin‐forming enzyme when the gland was at rest. The enzyme activity did not increase when secretin was added to the perfusing fluid, but when acetylcholine or pancreozymin was added, the activity rose about fourfold.6. These results are discussed in relation to the theory that plasma kinins play a prominent role in the functional vasodilatation of glandular tissues.