bluuebunny/crossref_metadata_2025 huggingface dataset:
RHEOLOGICAL PROPERTIES OF CRYSTALLIZED HONEY PREPARED BY A NEW TYPE OF NUCLEI
Authors: CHEN YUE‐WEN , LIN CHIH‐HAO , WU FU‐YU , CHEN HUI‐HUANG
Published: December 2008

Good spreadability is a highly desirable quality for crystallized honey used in product applications. In this study, we processed Taiwanese liquid litchi honey into crystallized honey by adding a new nuclei material, namely 0.1% (w/w) glucose powder, instead of the traditional 5–10% (w/w) natural nuclei. Rheological properties of the resulting product were determined during heating and cooling utilizing small amplitude oscillatory shear to assess spreadability. As the product was heated, it exhibited decreased consistency and improved fluidity (evidenced by decreasing storage modulus [G′] and loss modulus [G″] values) and three distinct regions within the G′curve (“softening,”“crystalline plateau” and “melting”). As the product was cooled from 55 to 0C, moduli were lower than those obtained during heating, and the product did not exhibit the three G′curve regions across the temperature range. Therefore, we observed incomplete reversible crystallization and rheological properties during temperature migration. Flow properties of crystallized honey in the 0∼25C temperature range could be successfully predicted using the Herschel–Bulkley model (R2 > 0.97). However, the product approached Newtonian flow behavior as temperatures neared the upper end of this range. Higher viscosity and lower yield stress were observed at temperatures below 15C. The crystallized honey developed for this study exhibited shear‐thinning properties desirable in honey products intended to be spread.

PRACTICAL APPLICATIONS

Crystallized honey is traditionally prepared by introducing 5–10% natural nuclei into liquid honey. Our lab developed a new method that replaces the natural nuclei with glucose powder, which, at 0.1% (w/w), produces a good quality creamed honey that, in commercial production, offers the potential for significant production cost advantages. As crystallized honey is used in commercial/consumer applications as a spread, its dynamic rheology is of both academic and industrial interest. In this study, we discuss the physical properties of the crystallized honey developed using glucose powder to help better identify the factors and variables involved in honey spreadability and thus facilitate the development of better honey products with more desirable spreadability profiles. This study also provides a rheological properties and spreadability database for crystallized honey that reflects the range of temperature changes that can be expected to occur during normal product storage and use.
MOISTURE‐DEPENDENT PHYSICAL PROPERTIES OF CHICKPEA SEEDS
Authors: NIKOOBIN M. , MIRDAVARDOOST F. , KASHANINEJAD M. , SOLTANI A.
Published: December 2008

This study was carried out to determine the effect of moisture content on several handling and bulk properties of two varieties of chickpea seeds, Arman and Hashem. Five levels of moisture content ranging from 5 to 35 (% wet basis) were used. The length, width, thickness and unit mass of the Arman variety increased from 8.46 to 9.71 mm, 6.66 to 7.81 mm, 6.99 to 8.36 mm and 0.28 to 0.42 g, respectively, as the moisture content increased. The respected values for the Hashem variety varied from 8.46 to 9.3 mm, 6.65 to 7.42 mm, 6.93 to 7.85 mm and 0.22 to 0.38 g, respectively. In the Arman variety, the sphericity increased from 86.64 to 88.47%, the geometric mean diameter increased from 7.33 to 8.59 mm, bulk density decreased from 813 to 710 kg/m3, true density decreased from 1,336 to 1,236 kg/m3, porosity increased from 39.15 to 42.55% and the coefficient of static friction increased linearly against all the tested surfaces as the moisture content increased. In the Hashem variety, the sphericity increased from 86.35 to 87.65%, the geometric mean diameter increased from 7.3 to 8.15 mm, bulk density decreased from 816 to 713 kg/m3, true density varied from 1,338 to 1,236 kg/m3, porosity increased from 38.97 to 42.31% and the coefficient of static friction increased linearly against all the tested surfaces as the moisture content increased. Individual volume and angle of repose for filling and emptying increased linearly with increasing moisture content for both varieties.

PRACTICAL APPLICATIONS

In this study, some engineering properties of chickpea seed were determined in order to design processing equipment and machinery for planting, harvesting and various postharvest operations such as cleaning, conveying, storage and cooking. Principal dimensions of chickpeas are important in sizing, sorting, sieving and other separation processes. Densities of chickpeas are necessary to design the equipment for processing and storing such as aeration systems, dryers and bins. The porosity affects the resistance to airflow through bulk chickpea seeds. During the harvesting, handling, processing and storage of chickpea seeds, the product exerts frictional forces on machinery components or storage structures. The magnitude of these frictional forces affects the amount of power required to convey the material.
DEVELOPMENT OF EXTRUDED SNACK FROM FOOD BY‐PRODUCTS: A RESPONSE SURFACE ANALYSIS
Authors: YAĞCI SIBEL , GÖĞÜŞ FAHRETTIN
Published: December 2008

Response surface methodology was used to investigate the effects of extrusion conditions including the moisture content of blend (12–18%), barrel temperature (150–175C), screw speed (200–280 rpm) and change in feed composition on the product characteristics of the snack food developed from rice grit in combination with durum clear flour, partially defatted hazelnut flour (PDHF) and fruit wastes. The blend was made up of rice grit (67%), durum clear flour (8–20%), PDHF (5–15%) and fruit waste (3–7%). The response variables were radial expansion ratio, color, and textural and sensory properties of the extruded snacks. Increasing the PDHF content caused a decrease in the radial expansion ratio, hardness and lightness of the snacks. The textural properties and color of produced snacks were affected by the fruit waste addition. Increasing the moisture content and decreasing the temperature caused an increase in the expansion ratio for most compositions. The extruded snacks with lower PDHF content had the highest levels of overall acceptance in the sensory panel. There was no significant effect (P < 0.05) of fruit waste addition on the sensory properties of the snacks.

PRACTICAL APPLICATIONS

Large amounts of side products of the food industry, in particular fruit and vegetable waste, evolved during production (most of which cause environmental pollution), preparation and consumption of foods. Because of this, it is necessary to collect and use these wastes for the production of new foods, which is important from the point of environmental pollution and a country's economy. This study aimed to produce a ready‐to‐eat, puffed and value‐added snack food by using the side products of various food industries. Durum clear flour of macaroni production, partially defatted hazelnut flour of hazelnut oil production and fruit wastes of various fruit juice production might be evaluated as the components of the extruded snack food product. The contribution of the present work is to propose an alternative technology for the utilization of food‐processing wastes for the development of a useful, value‐added extruded food product.
DEHYDRATION CHARACTERISTICS OF PAPAYA (CARICA PUBENSCENS): DETERMINATION OF EQUILIBRIUM MOISTURE CONTENT AND DIFFUSION COEFFICIENT
Authors: LEMUS‐MONDACA R. , BETORET N. , VEGA‐GALVÉZ A. , LARA‐ARAVENA E.
Published: December 2008

This study determined the drying kinetics behavior of papaya at different temperatures (40, 50, 60, 70 and 80C). Desorption isotherms were determined at 5, 20 and 50C over a relative humidity range of 10–95%. The Guggenheim, Anderson and de Boer models were found to be suitable for description of the sorption data. The samples reached equilibrium moisture of 0.10 ± 0.01 g water/g dry matter. Fick's second law model was used to calculate the effective diffusivity (6.25–24.32 × 10‐10 m2/s). In addition, experimental data were fitted by means of seven mathematical models. The kinetic parameters and the diffusion coefficient were temperature‐dependent and were evaluated by an Arrhenius‐type equation. The modified Page model obtained the best‐fit quality on experimental data according to statistical tests applied.

PRACTICAL APPLICATIONS

The main utility of this study is the application of both different empirical models and the diffusional model in tropical fruits' dehydration, which can be considered a basis for a very accurate estimation of drying time and the optimization of the same process. Two newly mathematical models are proposed in this study, through which a good fit on the data of experimental moisture content was achieved.

The study of drying of papaya cultivated in Chile engages a great technological interest, because this product is widely used in the development of different products such as candying, canning, juice, syrup and marmalade. In addition, papayas cultivated in Chile, along with other tropical fruits cultivated in Brazil, Colombia and the Caribbean, have become especially important in the exportations of these countries. The major markets for these products include the U.S.A., the European Community and Asia.
INVESTIGATION OF SUPERCRITICAL FLUID EXTRACTION OF PUERARIN FROM PUERARIA LOBATA
Authors: WANG LINGZHAO , YANG BAO , DU XIUQIAO
Published: December 2008

Puerarin, which is the most abundant isoflavone in Pueraria lobata, has many pharmacological effects. In this study, supercritical carbon dioxide extraction was employed as a novel and efficient technique to extract puerarin from Pueraria lobata. Effects of four variables (pressure, temperature, time and co‐solvent amount) on the puerarin yield of Pueraria lobata were investigated. Up to a certain value, the puerarin yield increased with increasing pressure; thereafter, puerarin yield decreased as pressure increased. A similar effect of temperature was also found. When the temperature was at 50C or the pressure was at 20 MPa, the highest puerarin yield obtained was 5.8 ± 0.3 mg/g. Positive effects of time and co‐solvent amount were observed on the puerarin yield. However, when the time was longer than 100 min or the co‐solvent amount was greater than 120 g, no significant improvement was detected in the puerarin yield. It was therefore important to define the level of each variable for an efficient preparation of puerarin. From the results obtained, supercritical carbon dioxide extraction was proved to be an efficient technique for extraction of puerarin from Pueraria lobata.

PRACTICAL APPLICATIONS

Pueraria lobata is a famous Chinese traditional medicinal herb which has been consumed by many people all over the world. Puerarin is the most abundant isoflavone in this herb, and it has been proven to have some important pharmacological properties. In this study, a novel technique called supercritical carbon dioxide extraction was employed to prepare puerarin from Pueraria lobata. Effects of pressure, temperature, time and co‐solvent amount on the puerarin yield were evaluated. The results were helpful in understanding the extraction process of puerarin and could give evidence for further developments on this special medicinal herb.
INACTIVATION KINETICS AND REDUCTION OF BACILLUS COAGULANS SPORE BY THE COMBINATION OF HIGH PRESSURE AND MODERATE HEAT
Authors: WANG BIAO‐SHI , LI BIAN‐SHENG , ZENG QING‐XIAO , HUANG JUAN , RUAN ZHENG , ZHU ZHI‐WEI , LI LIN
Published: December 2008

The combination effect of high pressure (400, 500 and 600 MPa) and moderate heat (70 and 80C) on the inactivation kinetics and reduction of Bacillus coagulans spore in phosphate buffer and ultra‐high temperature (UHT) whole milk was investigated. The pressure come‐up time and corresponding logarithmic reduction of spore inactivation were considered during pressure‐thermal treatment. B. coagulans spore had a much higher resistance to pressure in UHT whole milk than in phosphate buffer. Survival data were modeled using the linear, Weibull and log‐logistic models to obtain relevant kinetic parameters. The tailing phenomenon occurred in all survival curves, indicating the linear model was not adequate for describing these curves. The mean square error and regression coefficient suggested that the log‐logistic model produced best fits to all survival curves, followed by the Weibull model.

PRACTICAL APPLICATIONS

It becomes increasingly apparent that high‐pressure treatment combined with moderate heat treatment for low acid and acid products is often required for effective bacterial spores' inactivation. Consequently, the prediction model of microbial survival curves is essential. Bacillus coagulans is a slightly pressure‐resistant and relatively heat‐resistant spoilage bacterium of considerable concern during the processing of acid foods. Spore inactivation effect during the pressure come‐up time is sometimes considerable and should not beignored. The use of mathematical models to predict inactivation for spores could help the food industry further to develop optimum process conditions.
PERFORMANCE PREDICTION OF MEMBRANE MODULES INCORPORATING THE EFFECTS OF SUCTION IN THE MASS TRANSFER COEFFICIENT UNDER LAMINAR AND TURBULENT FLOW CONDITIONS FOR NON‐NEWTONIAN FLUIDS
Authors: AGARWAL SATISH , AGGARWAL ANKUSH , DASGUPTA SUNANDO , DE SIRSHENDU
Published: December 2008

Design equations for spiral wound membrane modules in case of power law fluid are derived for the first time. The case is solved for both laminar and turbulent flow regimes considering orange juice as the model system. The governing equations are solved numerically and the profiles of transmembrane pressure drop, bulk velocity, concentration, permeate flux, membrane surface concentration and permeate concentration along the membrane module are obtained. A detailed parametric study is carried out to observe the effects of operating conditions on the permeate flux and permeate concentration. The present analysis is helpful to design and simulate the performance of the membrane modules adequately. For the model system, it is observed that the axial pressure drop is about 2 to 3% of the inlet transmembrane pressure drop for 1.0 m length of the module. The mass transfer coefficient increases by twofold when the flow regime becomes turbulent. In case of laminar flow, at 7,000‐kPa inlet transmembrane pressure drop, the average flux is about 22 L/m2·h and the flux value under turbulent flow condition becomes about 30 L/m2·h at the same pressure drop. For a slightly leaky membrane, at 7,000‐kPa pressure drop and 130 kg/m3 of feed soluble sugar concentration, the permeate stream contains about 10 kg/m3 of total sugar.

PRACTICAL APPLICATION

The application of membrane technology is one of the emerging areas in food industry. The major application includes fruit juice clarification and concentration. Therefore, appropriate design of membrane modules is of utmost importance. Most of the fruit juices are non‐Newtonian in nature and they obey, in general, power law rheology. The derivation of detailed design equations of a spiral wound module is carried out considering a power law fluid, both under laminar and turbulent flow regimes. The presented method provides a way to design the membrane modules in great detail (i.e., incorporating effects of suction in mass transfer coefficient, developing concentration boundary layer, non‐Newtonian fluid, etc.). This will be helpful to design a spiral wound module to meet a target productivity (i.e., permeate flux) and permeate quality (i.e., permeate concentration).
FUZZY CLUSTERING MODELING AND EVALUATION OF SURFACE INTERACTIONS AND EMULSIONS OF SELECTED WHEAT PROTEIN COMBINED TO IOTA‐CARRAGEENAN AND GUM ARABIC SOLUTIONS
Authors: ABU‐GHOUSH MAHMOUD , SAMHOURI MURAD , YASEEN EMAD , HERALD THOMAS
Published: December 2008

Gums and proteins are valuable ingredients with a wide spectrum of applications. Surface properties (surface tension, interfacial tension, emulsion activity index [EAI] and emulsion stability index [ESI]) of 4% deamidated wheat protein (DWP) in a combination with iota‐carrageenan (IC) (0.05, 0.1 and 0.5%) or gum arabic (GA) (0.5, 1 and 5%) were investigated. The results showed that the addition of IC to 4% DWP significantly increased the surface tension, interfacial tension, EAI and ESI, whereas the addition of GA to 4% DWP significantly increased the surface tension and decreased the interfacial tension and EAI (except at 5% of GA). In addition, a fuzzy‐based clustering model was used to predict the surface properties of the DWP. The fuzzy model achieved accuracies of (97%, 90%, 97% and 75%) for predicting (EAI, ESI, surface tension and interfacial tension), respectively. This approach can be applied to predict many other parameters and properties in the food industry.

PRACTICAL APPLICATIONS

The surface properties (surface tension, interfacial tension, emulsion activity index and emulsion stability index) of wheat protein (DWP) in combination with iota‐carrageenan or gum arabic were investigated. In addition, subtractive clustering‐based fuzzy models for predicting the surface properties of DWP was constructed. This modeling can be used as an indicator of usefulness of fuzzy clustering in such a system which directly can be used as a tool by the food processors to produce a high quality beverage product.
THE RELATIONSHIP BETWEEN SELF‐CONTROL AND LANGUAGE: EVIDENCE OF A SHARED ETIOLOGICAL PATHWAY*
Authors: BEAVER KEVIN M. , DELISI MATT , VAUGHN MICHAEL G. , WRIGHT JOHN PAUL , BOUTWELL BRIAN B.
Published: December 2008

Converging lines of research suggest that self‐control and language may be inextricably linked. No empirical research has ever examined this proposition, however. We address this gap in the literature by analyzing a sample of twin pairs from a nationally representative data set of children. The results revealed three broad findings. First, diminished language skills were predictive of low self‐control both cross‐sectionally and longitudinally. Second, the covariation between language and self‐control was linked to both genetic and environmental factors. Third, after controlling for genetic influences on self‐control, language skills were predictive of variation in individual levels of self‐control. The theoretical implications of these findings are discussed.
Reflex Adrenergic Inhibition of Gastric Motility Elicited from the Gastric Antrum
Authors: Abrahamsson Hasse
Published: December 2008

The reflex effects of distension and contraction of the gastric antrum on corpus‐fundus motility were studied in anesthetized cats. Besides a vagally mediated reflex corpus‐fundus relaxation, antral distension elicited a prompt reflex inhibition of corpus‐fundus contractions that was present also after vagotomy. In vagotomized animals this inhibitory reflex persisted also after cervical spinal cord transection, but was abolished by spinal anrsthesia or by guanethidine. Stepwise increases of antral distension revealed that the reflex corpus‐fundus inhibition appeared already at distending pressures of 5–10 cm H2O, then increased in a graded fashion and could be maintained for at least 10 min if a steady distension was applied. Also “isometric” antral contractions were effective in eliciting the reflex corpus‐fundus inhibition. — It is concluded that activation of slowly adapting “tension receptors” in the antral gastric wall inhibits gastric (corpus‐fundus) motilityviaa spinal reflex mechanism, mediated by splanchnic adrenergic fibres that seem to suppress the intramural excitatory cholinergic neurons. This gastro‐gastric adrenergic inhibitory reflex seems to be activated concomitantly with a vago‐vagal gastro‐gastric relaxatory reflex. It is suggested that these two suppressive reflex mechanisms play an important role in regulation of gastric motor functions.
Response of Isolated Frog Muscle Spindle to Sine Wave Stimulation
Authors: McReynolds J. S. , Ottoson D.
Published: December 2008

The impulse response and the receptor potential 01 the isolated muscle spindle of the frog were recorded during sinusoidal stretching at frequencies from 0.1 c/s to 100 c/s. Attention was focused on the changes of the responses in the initial phase of stimulation before the steady state was reached. In the course of sine wave stimulation the impulse response of the spindle undergoes regular changes characterized by an increase in threshold and latency of the individual impulses, a decrease in phase lead and peak frequency and a reduction in number of spikes in each cycle. The changes are most pronounced during the first 2–5 cycles, and a steady state with a fixed impulse patterning is usually reached after 10–15 cycles. The receptor potential evoked by a sine wave stretch is distorted in comparison with the waveform of the stimulus in having a relatively faster rise and slower decay. With changes in frequency and amplitude of stimulation it undergoes characteristic alterations in phase lead and configuration. When superimposed upon a constant stretch or a linearly rising stretch, sinusoidal stimulation produces responses which increase in amplitude with the underlying stretch. These observations provide evidence that the sensory endings responsible for the transducer action do not obey linear transfer functions.
Absorption from the Ambient Water and Combustion of Ethanol in Young Atlantic Salmon (Salmo salar L.) at Different Temperatures
Authors: Höglund Lars B. , Pilström Lars , Sjöblom Mats
Published: December 2008

After 5–10 h exposure in static bio‐assays first‐summer Salmo salar live in equilibrium with the ambient ethanol concentration of 117 mmol/1 at 10° and 16° C. At 4° C this equilibration is retarded and is not evident until after 24 h. A quantitative connection between ethanol oxidation (M) and body weight (W) in accordance with the general formula M = K × Wb seems to exist for young salmon at 16° C. From the present tests the numerical values of the constants K and b were estimated to be approximately 10.5 and ‐1.03 respectively. Changes in behaviour induced by ethanol and the influence of temperature upon the metabolism of ethanol are discussed briefly.
Prostaglandin Action on Noradrenaline Release and Mechanical Responses in the Stimulated Guinea Pig Vas Deferens
Authors: Hedqvist Per
Published: December 2008

PGE1and PGE2reversibly and dose‐dependently inhibited transmitter release from the stimulated guinea pig vas deferens. The two compounds proved equiactive and more prone to inhibit transmitter release at a low than at a high stimulation frequency. The PGEs inhibited the twitch response but produced inconsistent effects on contractions induced by prolonged stimulation. The difference may be due to the fact that the PGEs reduce the excitatory junction potentials and depolarize the effector cell membrane. Phenoxybenzamine increased transmitter release in response to nerve stimulation but failed to significantly alter the inhibitory effect of PGE2. It is therefore concluded that PGEs and presumed presynoptic α‐receptors probably intrude upon different levels of the process of excitation secretor, coupling. A possible model for the action of locally formed PGEs on the neuromuscular transmission of the vas deferens is advanced.
Effects of Lanthanum on Potassium Contractures of Isolated Twitch Muscle Fibres of the Frog
Authors: Andersson K.‐E. , Edman K. A. P.
Published: December 2008

The effects of lanthanum on the time course of potassium‐induced contractures of isolated muscle fibres from the frog were investigated. Two kinds of effects could be distinguished: 1. A reduction in the rate of tension development and a decrease in contracture amplitude; 2. A prolongation of the tension plateau and a decrease in the rate of relaxation during sustained depolarization. The effects under point 1 were obtained at lanthanum concentrations ≥ 0.5 mM, while those under point 2 were clearly visible at lanthanum concentrations as low as 0.01 mM. In a calcium‐free medium containing 0.1 mM lanthanum, a muscle fibre produced repeatable contractures to 117.5 mM potassium over many hours. The slowing of tension development and the diminished contracture amplitude is explainable on the basis of a reduction in the rate of release oi activator calcium in response to a depolarization step. The prolongation of the platmu and the slowing of relaxation caused by lanthanum is interpreted as reflecting a reduced rate of inactivation of thc calcium‐release mechanism following depolarization.
Action of Insulin on Vascular and Intestinal Smooth Muscle. Effects on Amino Acid Transport, Protein Synthesis and Accumulation of Glucose Carbon
Authors: Arnqvist Hans J.
Published: December 2008

The effects of insulin (0.1 U/ml) on the glucose metabolism in vascular and intestinal smooth muscle are weak in comparison with those in skeletal muscle and also appear later (Arnqvist 1973). In this study insulin (0.1 U/ml) was found to stimulate the membrane transport of α‐aminoisobutyric acid‐14C (AIB‐14C) and the incorporation of leucine‐14C into protein in bovine mesenteric arteries and rabbit colon smooth muscle. Also these effects were weaker and appeared later than the corresponding effects in skeletal muscle. The dose‐response curves for the accumulation of glucose‐14C and the incorporation of leucine‐14C into protein in bovine mesenteric arteries were both displaced to the right in comparison with those for rat diaphragm. Blocking protein synthesis by puromycin did not abolish the effect of insulin on the accumulation of glucose‐14C. The sensitivity of bovine mesenteric arteries to the effect of insulin on the accumulation of glucose‐14C did not increase during the incubation period. The finding that all the diverse effects of insulin on smooth muscle were weaker and appeared later than those in skeletal muscle may indicate that they are initiated by a common receptor mechanism which differs in smooth muscle and skeletal muscle.
Group I Inhibition in Ib Excited Ventral Spinocerebellar Tract Neurones
Authors: Lindström S. , Schomburg E. D.
Published: December 2008

The convergence of inhibition and excitation from muscle spindle Ia and Golgi tendon organ Ib afferents was investigated in ventral spinocerebellar tract (VSCT) neurones monosynaptically excited from Ib afferents. Although most cells received Ib excitation from several nerves, the dominating excitation was supplied from nerves to synergistic muscles acting as either flexors or extensors at one joint. Disynaptic Ia lPSPs from the nemc to the knee extensor were common in cells with their main Ib excitation from the nerves to either hip, knee or ankle extensors or to knee flexors. The Ia IPSPs in cells excited from hip extensors and knee flexors were depressed by antidromic impulses in motor axons, while no such effect occurred on Ia IPSPs in the other cells. The Ia IPSPs in Ib VSCT neurones thus seem to be mediated by two different groups of Ia inhibitory interneurones, with and without recurrent inhibition from motor axon collaterals through Renshaw cells. Disynaptic Ib IPSPs from nerves to thigh muscles were rare while presumed Ib IPSPs from nerves to ankle and toe muscles were more common. In some cells there were indications of convergence of monosynaptic EPSPs and disynaptic IPSPs from Ib afferents in the same nerve. The results are discussed in relation to the hypothesis that the VSCT relays information about interneuronal transmission in the spinal cord.
Recovery Time in the Visual Cortex of Guinea Pigs and of Ground Squirrels
Authors: Hammerberg Poul E.
Published: December 2008

The cortical irresponsive and recovery times were tested in albino guinea pigs and in ground squirrels with the same brief (1 ms) colored flashes and using the same anesthesia, dial. The irresponsive time was much longer, 60–80 ms, in the guinea pig compared with 15–20 ms in the squirrel. In the squirrel the retinal was at least 5 ms shorter than the cortical recovery time, and the retinal response reached 50 % of full amplitude when 25 ms separated the flashes compared with 100 ms for the cortical response. Since the conditioning and testing flashes had the same intensity, the irresponsive time diminished with decreasing strength of light until close to threshold in the guinea pig. The threshold was high in squirrel and flashes of maximum intensity were used with color filters. There was no difference between responses to colored flashes when the amplitude of the responses was the same, either in guinea pig or squirrel. In the guinea pig chloralose‐urethane anesthesia resulted in a longer irresponsive time, and with some light intensities there was a period when the response to the testing flash was larger than to the first flash, as has been described in cat.
Uptake of Histamine or Histamine Metabolites into Sympathetic Nonadrenergic Axons
Authors: Ehinger B.
Published: December 2008

Rabbit tissues were exposed to tritiated histamine or histidine either by intraocular injections (iris) or by incubations (iris, superior cervical ganglion). When the iris was exposed to tritiated histamine, radioactivity appeared in a pattern very similar, but not completely congruent, to that of the adrenergic terminals. The neuronal radioactivity disappeared after sympathetic denervation and also after decentralization of the superior cervical ganglion. Application of tritiated histidine did not give rise to any neuronal radioactivity. Sympathetic ganglion cells did not accumulate histamine under conditions when nerve fibres did. The experiments suggest the possibility of a set of sympathetic nonadrenergic axons accumulating histamine or histamine metabolites. If so, these axons run close to the adrenergic terminals, and presumably they arise in structures situated centrally of the superior cervical ganglion. It is further concluded that there is under normal conditions no very efficient neuronal conversion of histidine to histamine in the uvea.
Pulmonary Vascular Effects of Suddenly Induced Unilateral Blood Platelet Aggregation
Authors: Bø G. , Hognestad J.
Published: December 2008

Embolization of one or both lungs was achieved in cats by intravascular infusions of a collagen suspension. On intravenous collagen infusion, with platelet aggregates reaching the vasculature of both lungs, large pulmonary pressor responses were obtained. Unilateral platelet aggregation in blood to the lungs was achieved by infusion of collagen into the right pulmonary artery. The resulting pressure/flow response indicated that blood flow was diverted to the contra‐lateral lung. There was no indication that the pulmonary vascular resistance was increased in this contralateral. non‐embolized lung. It appears therefore that only vasculature in the lung which received platelet emboli is involved in the vasoconstriction following unilateral embolization of this type.
Lowered Chronotropic Sensitivity of Rat and Frog Hearts to Sympathomimetic Amines Following Cold Acclimation
Authors: Tirri R. , Harri M. N. E. , Laitinen Leena
Published: December 2008

Cold acclimation elevated the basic heart rate in the rat and decreased the chronotropic sensitivity to noradrenaline and isoprenaline. These changes reached their maximum after a week but returned to the initial level after a month of prolonged cold acclimation. Phenylephrine failed to increase the heart rate under thein uiuoconditions used. In the frog, cold acclimation lowered the heart chronotropic sensitivity most significantly to phenylephrine, less to adrenaline and not at all to isoprenaline, as indicated by changes in the EDSO‐values. This lowered sensitivity to adrenaline reached its maximum level after 2–4 days of cold exposure and had not returned to normal after 20 days. In both cold‐ and warm‐acclimated frogs the elevation of the temperature, where the heart rate was measured, decreased the sensitivity to phenylephrine.
Afferent Discharge from Human Muscle Spindles in Non‐Contracting Muscles. Steady State Impulse Frequency as a Function of Joint Angle
Authors: Vallbo A. B.
Published: December 2008

Impulses in single muscle spindle afferents from the antebrachial finger flexor muscles were recorded from the median nerve of waking human subjects. The discharge frequency in the steady state was measured as the metacarpo‐phalangeal joint angles were passively changed in steps. At a comfortable resting position of the hand, less than ten percent of the spindle primaries were discharging. Within intermediate ranges of muscle lengths the discharge frequency of the single units did not exceed 20 impulse per second (ips). The response to joint movements was that expected from muscle stretch and muscle release alone and there was no indication of fusimotor adjustments as a result of joint movement. The frequency of the single units increased linearly with joint extension, the mean sensitivity of the primaries being 0.18 ips per degree which is about 5 times lower than the sensitivity of de‐efferented spindles in cat ankle extensors. The afferent discharge from the secondaries was in most respects very similar to that of the primaries. The low discharge frequency, the low percentage of active units and the low position sensitivity all indicate an insignificant fusimotor outflow to relaxed human hand muscles and a comparatively poor ability of the spindles to measure muscle length under these conditions.
Effects on Cerebral Energy State of Arterial Hypotension in Rats with Porta‐Caval Anastomosis
Authors: Holmin Torsten , Jóhannsson Halldór , Siesjö Bo K.
Published: December 2008

The influence of arterial hypotension upon the energy state of thc brain was studied in rats with porta‐caval anastomosis by bleeding the animals to mean arterial blood pressures of 45 and 30 mm Hg, respectively. Reduction of blood pressure to 45 mm Hg in shunted rats gave no or only very moderate accumulation of lactate and there were no changes in the contents of ATP, ADP and AMP in frontal lobe or brainstem. At a mean blood pressure of 30 mm Hg shunted animals and controls showed similar values for glycolytic and citric acid cycle intermediates, amino acids and adenine nucleotides in frontal lobe, parietal cortex and Drainstem. It is concluded that the shunting procedure, and the ensuing hyperammonemia, does not adversely affect the sensitivity of the cerebral energy state to arterial hypotension.
Respiratory and Cardiovascular Responses to Electrical Stimulation of the Avian Brain with Emphasis on Inhibitory Mechanisms
Authors: Kotilainen P. V. , Putkonen P. T. S.
Published: December 2008

Respiratory and circulatory responses to electrical brain stimulation were studied in 30 anesthetized chicken from about 850 histologically verified loci in an attempt 1) to delineate the limits and characterize the response patterns of a thalaniic cardioinhibitory area (Putkonen 1967) and 2) to extend exploration of respiratory and circulatory functions of the avian brain to telecephalic and mesencephalic levels. Apnea or partial respiratory inhibition were obtained from; 1) an anterolateral thalamic field in front and around the nurotundus, 2) the entire course of the quinto‐frontal tract, which was the only forebrain site yielding apnea and from 3) a medial and a lateral mesencephalic area. The apnea from the antero‐lateral thalamus was associated with progressive bradycardia and fall in blood pressure which both could be almost abolished during tracheal infusion of oxygen. Apneic bradycardia from the mesencephalic quinto‐frontal tract was associated with hypertension thus mimicking the “diving reflex”. Varying patterns of respiratory and circulatory activation, often with vocalizations, were obtained from; 1) septal and preoptic areas, 2) medial archistriatal regions, 3) the occipito‐mesencephalic tract and from 4) a large field in the mesencephalic lateral reticular formation. The results are discussed in relation to pertinent literature from birds and mammals with an emphasis on inhibitory mechanisms.
Labelled 5‐Hydroxytryptamine and 5‐Hydroxyindoleacetic Acid Formed in Vivo from ‘H‐Tryptophan in Rat Brain; Effect of Probenecid*)
Authors: Schubert Johan
Published: December 2008

Procedures were developed for determination of labelled 5‐hydroxytryptamine (5‐HT) and 5‐hydroxyindoleacetic acid (5‐HIAA) formedin viuofrom3H‐tryptophan in rat brain. Tryptophan, 5‐HT and 5‐HIA.4 in brain extracts were isolated on columns of Dowex 50W‐X4, Amberlite CG 50, and Sephadex G 10, recoveries being 64 %, 78 % and 66 % respectively. Following i.v. injection of3H‐tryptophan labelled 5‐HT and 5‐HIAA accumulated in brain, reaching maximal levels after approximately 15 and 60 min respectively. The relationship between the specific activity curves for 5‐HT and 5‐HIAA appeared to be consistent with single compartment kinetics for 5‐HT. The effect of probenecid (200 mg/kg) on the amounts of labelled 5‐HT and 5‐HIAA formed from3H‐tryptophan indicates that besides inhibiting 5‐HIAA efflux from brain the drug also enhances 5‐HT synthesis.
Intracortical Distribution of Renal Blood Flow during Saline Infusion in Dogs
Authors: Løyning E. W.
Published: December 2008

The increase in sodium excretion induced by isotonic saline infusion has been attributed to a redistribution of blood flow within the cortex to “salt‐loosing” superficial nephrons. To test this hypothesis, mean blood flow to outer (OCF) and inner (ICF) cortex was measured in dogs before and during saline expansion, using H2‐clearance rates as indicator of local blood flow. Mean total blood flow (RBF) was measured with an electromagnetic flowmeter. During infusion of 0.9 % NaCI, 30 ml/min for 30–80 min, urine flow increased from 1.1 to 7.5 ml/min, glomerular filtration rate from 39.8 to 49.1 ml/min, RBF rose from 214 to 276 ml/min, OCF from 3.43 to 3.87 ml/min and ICF from 3.50 to 3.91 ml/min. OCF/ICF did not change significantly during saline expansion. Autoregulation of local blood flow was maintained after saline loading with no change in OCF/ICF within the pressure range of autoregulation. Since massive saline infusion is followed by a parallel increase in blood flow to outer and inner cortex, it is concluded that intracortical redistribution of blood flow is not the mechanism of natriuresis during saline loading.
Renal Lithium Clearance during Dehydration and Rehydration with Water or 0.9% NaCl in the Rat
Authors: Smith Donald F.
Published: December 2008

Male albino rats fed a diet containing lithium were dehydrated by 24 h of water deprivation and then rehydrated with demineralized water or 0.9 % NaCl. Renal lithium clearance decreased during rehydration with water. Rehydration with 0.9 % NaCl prevented the fall in the rate of urinary lithium elimination. The decrease in renal lithium clearance in the rats rehydrated with water was due to an increased fractional reabsorption of lithium in the renal tubules and was associated with a decrease in renal sodium clearance. The relationship between the renal elimination of sodium, potassium, and lithium during rehydration is discussed.
Actions of Intravenous Ca++ and Na+ on Body Temperature in Rabbits
Authors: Nielsen Bodil
Published: December 2008

Rectal temperatures in rabbits were found to increase when hyperosmotic NaCl solution were infused in the marginal earvein, while infusion of CaCl2 caused a fall in rectal temperature. The latter effect was much more pronounced in cold (14° Ta) environment. It could be shown that the ions affected the peripheral circulation and therefore the heat loss. It is concluded that the observed changes in body temperature most likely are secondary to the peripheral changes in heat loss, and not a thermoregulatory change in the set‐point of the hypothalamic centres.
Contraction in Venous Smooth Muscle Induced by Hypertonicity. Calcium Dependence and Mechanical Characteristics
Authors: Andersson Christer , Hellstrand Per , Johansson Börje , Ringberg Anita
Published: December 2008

A tonic increase in tension was observed in the isolated rat portal vein in response to large increases in extracellular tonicity (1.5–3 times normal). The purpose of this study was to find out whether this tension increase was due to active contraction or passive shrinkage. The metabolic dependence of the response and its mechanical characteristics, as revealed by quick release experiments, lead to the conclusion that active contraction is the predominant mechanism. The maximal force developed in the hypertonicity contracture amounted to 31 per cent of the maximal K+ contracture obtained in isotonic medium. The hypertonicity contracture occurred independent of the level of membrane potential and in the absence of external Ca2+ (below 10‐‐9 M). It is thus elicited through mechanisms which differ in these respects from the electromechanical cbupling operating in the K+ contracture. The speed of shortening against a given afterload was found to be lower in a hypertonicity contracture than in a K' contracture of comparable isometric force. Explanations for observed differences between the two types of contracture are discussed.
Renal Control of Salt and Fluid Homeostasis during i. v. Saline Infusion
Authors: Aperia Anita , Broberger Ove
Published: December 2008

The renal effect of infusion of hypo‐, iso‐ and hypertonic saline has been studied in dogs. The infusion rate was comparatively low, 1 % of the b.wt./45 min. The kidneys responded almost instantaneously to the infusion with diuresis and natriuresis. The response was due primarily to an adaptive inhibition of tubular reabsorption. Increases in filtered load of Na+ occurred only as a function of increased serum Na+ concentration, i.e. only when the hypertonic saline solution were used. The inhibition of tubular reabsorption was mainly signalled by the fall in serum protein concentration. Changes in Na+ balance and serum Na+ concentration did not contribute to the adaptive inhibition of tubular reabsorption. The effect of the diuretic and natriuretic response on fluid and Na+ balance depended primarily on the tonicity of the infused fluid. When the 75 and 150 mEq solutions were used, fluid balance became positive, but did not increase much when more than 2 % of the b.wt. had been given. When the hypertonic saline solutions were used total fluid balance became increasingly negative. The Na+ balance was best controlled with the hypotonic saline solution. Vhen hypertonic saline waq given Na+ balance increased almost at the same rate as Na+ was given.
A Colloid Osmometer for Small Fluid Samples
Authors: Aukland K. , Johnsen H. M.
Published: December 2008

A membrane colloid osmometer for measurement on samples down to 5 μl has been developed. Pellucid acryl plastic is used for most parts of the osmometer, allowing visual inspection of the reference fluid chamber. The osmometer base is attached directly to a Hewlett‐Packard pressure transducer, replacing the original dome of the transducer, thereby avoiding extra connections and leakage. The exposed membrane area has a diameter of 3 mm, and the membrane may be changed without completely disassembling the osmometer. With Amicon UM‐10 membranes and 0.9 % saline as reference fluid, the equilibration time for measurements on human sera was 2–4 min. Reduction of equilibration time to about 1 min was obtained by “priming” and flushing the membrane with serum ultrafiltrate. Reproducible measurements were obtained on samples down to 4–5 μl.
Acceleration Stress and Effects of Propranolol on Cardiovascular Responses
Authors: Bjurstedt H. , Rosenhamer G. , Tydén G.
Published: December 2008

Heart rate, arterial pressure and cardiac output were recorded in six physically well‐trained, young male volunteers in the sitting position at normal gravity and at 3 G acting in the head‐seat direction, before and after beta‐adrenergic blockade by propranolol. Studies were performed both at rest and during leg exercise at a load corresponding to 50 % of the maximal oxygen uptake. After propranolol, the heart rate response to increased G at rest averaged 38 % of that observed without blockade, indicating that G‐induced cardioaccelera‐tion is predominantly due to sympathetic stimulation. G‐induced decline of cardiac output was more marked after propranolol, this effect being entirely due to the reduced response of the heart rate. In spite of the cardioinhibitory effects of propranolol, subjective G tolerance was well preserved; the response of the arterial mean pressure to increased G was unaffected due to a 65 % rise in systemic vascular resistance as against 43 % before propranolol. Hence, sympathetic chronotropic stimulation of the heart is not essential for the circulatory defense against increased gravitational stress. Transition from rest to exercise at 3 G produced a larger increase in stroke volume than in heart rate; after beta‐adrenergic blockade the dominance of the stroke xolume increase was exaggerated.
Hemodynamic Effects of Chloralose and Propranolol in Dogs
Authors: Halkola Lauri , Koivikko Antti , Länsimies Esko
Published: December 2008

Heart rate, mean arterial pressure, cardiac output, and stroke volume (dye‐dilution method) were determined in 10 awake dogs. Then the animals were given propranolol and a‐chloralose. 5 dogs were β‐blocked before α‐chloralose and 5 dogs received the drugs in reverse order. The initial responses to the administration of the drugs were insignificant. The final cardiac output of dogs receiving Acta physiol. scand. 197.4 90. ‐chloralose first was lower than that of dogs receiving the same drugs in reverse order. The difference was due to (central or peripheral) α‐chloralose effect which weakende the cardiovascular ability to compensate a decrease of cardiac output. It was also observed that β‐blocking prevented and abolished the convulsions and tachnypnea caused by α‐chloralose.
5‐HT Storage in Rat and Rabbit Blood Platelets: The Separation of ATP‐Containing and Sulphomucopolysaccharide‐Containing Granules
Authors: Anderson Per , Slorach Stuart A. , Uvnäs Börje
Published: December 2008

Sonicated rabbit and rat platelets were subjected to differential centrifugation and the mixed organelle fraction so obtained then separated by ultracentrifugation on a discontinuous sucrose gradient. The distribution curves for 5‐hydroxytryptamine (5‐HT), histamine (studied in rabbit only) and adenosine‐5′‐triphosphate (ATP) were similar. Electron microscopy of the amine‐containing fractions revealed the presence of very dense granules. These fractions contained little or no hexosamine or35S, two indicators of the presence of sulphomucopoly‐saccharides (SMPS). A second type of granule, a‐granules, was found in fractions corresponding to peaks on the hexosamine and35S distribution curves. The observation that in rabbit 5‐HT, histamine and ATP are localized to the same subcellular fractions as the very dense granules agrees with the results of earlier workers. An analogous situation appears to exist in rat platelets. The biogenic function of the SMPS‐containing a‐granules remains uncertain. It might be suggested that they, like the mast cell granules, utilize their SMPS‐protein complex for the storage of electrically charged substances.
Efferent Chorda Tympani Activity and Salivary Secretion in the Rat
Authors: Hellekant Göran , Hagstrom Earl C.
Published: December 2008

It is known that nerve impulses to the mandibular salivary gland must be carried in the chorda tympani proper nerve, although they have never been recorded. This study presents recordings of efferent impulses in this nerve and simultaneous observations of secretion from this gland in rats under neuroleptic analgesia, during electrical stimulation of he salivary nuclei in the brainstem. Stimulation was found to increase the impulse activity in the nerve and to lead to secretion of saliva. The secretion ceased when the nerve was blocked. The relationship was best described by a straight line plot of the logarithm of the increased nerve activity against secretion, the correlation coefficient being 0.84. Barbiturate abolished the effect of brain stimulation. This indicates that nuclear structures, and not chorda tympani fibres, were being stimulated.