CLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 4 2008
Ya Ping Lee
SUMMARY 1Prevention of hypertension and improved blood pressure control can be achieved through dietary modification. In particular, population studies and randomised controlled trials have indicated a beneficial effect of both dietary protein and dietary fibre on level of blood pressure. 2A large population study indicates that an increase in 37 g/day of protein leads to a decrease in mean systolic and diastolic blood pressure by approximately 3 and 2.5 mmHg, respectively. This protective effect is independent of the source of dietary protein. 3Meta-analysis suggests that a fibre increase of approximately 17 g/day will decrease systolic blood pressure by 1.15 mmHg and diastolic blood pressure by 1.65 mmHg, with soluble fibre showing a stronger effect than insoluble fibre. 4Protein and dietary fibre may have additive effects to lower blood pressure. One feasible approach to increasing both protein and fibre in the daily diet could be through the incorporation of legumes, a protein- and fibre-rich food. 5This review assesses the evidence for effects of protein and fibre to reduce blood pressure and the potential of incorporation of legumes into the daily diet as a feasible approach to achieving such benefits for blood pressure. [source]

Comparison between objective and subjective measurements of quality of service over an Optical Wide Area network

EUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, Issue 3 2008
Francesco Matera
The introduction of intelligence for management and control of the quality of service (QoS) are key issues for the evolution of the next generation IP optical network based on Ethernet technology. A test bed of a core-access network was implemented to investigate such issues and in this paper, the authors report measurements concerning the QoS of multimedia services for different traffic conditions. The network was implemented with a differentiated service over Multi-Protocol Label Switch (MPLS) architecture; it consists of a real optical network based on core routers with optical Gigabit Ethernet (GBE) interfaces connected by means of long single mode fibres (about 50\,km), contained in an installed cable between Rome and Pomezia. The network is based on different access devices, but in this paper we only refer to an access based on Fibre To The building (FTTB) architecture. The QoS was investigated both in terms of network (or objective) tests that include packet loss, jitter, one way delay and throughput measurements and perceptive (or subjective) tests that conversely are based on the evaluation of user perception. The services under test mainly consisted of video streams that circulated in the network according to the switching operations based in the IP differentiated service over MPLS technique that allowed us to guarantee the QoS for some class of service, also in the presence of network overload. Particular attention was given to the correlation between objective and subjective measurements. Furthermore, in order to have a complete analysis about QoS of real networks, measurements were performed also in the presence of restoration operations for link failures; in particular we compare the results in the case of conventional IP network restoration with a procedure proposed by us and based on a link switching activated by the loss of signal command coming from the routers. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Dedicated Applications of Carbon Fiber Reinforced Plastics in Machine Engineering

ADVANCED ENGINEERING MATERIALS, Issue 3 2004
B. Wielage
Machine engineering has an inherent potential concerning the use of high performance material like Carbon Fibre Reinforced Plastics. The authors show some successful substitutions of formerly conventionally designed components by CFRP-parts. The examples are taken from several branches of machine engineering, especially from textile machine engineering. [source]

Systematic review: the role of different types of fibre in the treatment of irritable bowel syndrome

ALIMENTARY PHARMACOLOGY & THERAPEUTICS, Issue 3 2004
C. J. Bijkerk
Summary Background :,Both high-fibre dietary advice and the prescription of fibre as a bulking agent are very common in primary and secondary care management of irritable bowel syndrome. Irritable bowel syndrome patients with constipation may have delayed intestinal transit. Therefore, fibres that accelerate intestinal transit may be beneficial in these patients. The uncertain benefits reported in several clinical studies, however, have led us to reappraise the value of fibre in irritable bowel syndrome management. Aim :,To quantify the effect of different types of fibre on global and symptom relief from irritable bowel syndrome. Methods :,Using a structured literature search in MEDLINE (1966,2002), we selected randomized controlled trials involving irritable bowel syndrome patients treated with fibre. Analyses were performed for the total group and for trials using soluble and insoluble fibre separately. Results :,Seventeen studies were included in the analysis. None investigated primary care irritable bowel syndrome patients. Fibre, in general, was effective in the relief of global irritable bowel syndrome symptoms [relative risk, 1.33; 95% confidence interval (CI), 1.19,1.50]. Irritable bowel syndrome patients with constipation may receive benefit from fibre treatment (relative risk, 1.56; 95% CI, 1.21,2.02), but there was no evidence that fibre was effective in the relief of abdominal pain in irritable bowel syndrome. Soluble and insoluble fibre, separately, had different effects on global irritable bowel syndrome symptoms. Soluble fibre (psyllium, ispaghula, calcium polycarbophil) showed significant improvement (relative risk, 1.55; 95% CI, 1.35,1.78), whereas insoluble fibre (corn, wheat bran), in some cases, worsened the clinical outcome, but there was no significant difference compared with placebo (relative risk, 0.89; 95% CI, 0.72,1.11). Conclusions :,The benefits of fibre in the treatment of irritable bowel syndrome are marginal for global irritable bowel syndrome symptom improvement and irritable bowel syndrome-related constipation. Soluble and insoluble fibres have different effects on global irritable bowel syndrome symptoms. Indeed, in some cases, insoluble fibres may worsen the clinical outcome. Future clinical studies evaluating the effect and tolerability of fibre therapy are needed in primary care. [source]

Pressure-Assisted Spinning: A Versatile and Economical, Direct Fibre to Scaffold Spinning Methodology

MACROMOLECULAR RAPID COMMUNICATIONS, Issue 14 2007
Sumathy Arumuganathar
Abstract Spinning composite polymer fibres by means of electric fields has been investigated for well over a century. These spun fibres have been explored across many areas of research, spanning the physical to the life sciences; however, electrospinning has the hazardous nature of the high voltage at the spinning needle. We demonstrate here a competing direct fibre to scaffold preparation method, completely determined by an applied pressure. Our technique reported here removes the hazardous high-voltage element from the fibre/scaffold formation technique and has the ability to form uniaxial fibres and scaffolds comparable to those fabricated by electrospinning. We refer to this fibre generation approach as "pressure-assisted spinning (PAS)", which will have a tremendous impact in a range of applications, spanning the physical through to the life sciences. PAS joins the techniques for fibre to scaffold generation with a view to significantly and globally contributing to the micro- and nanosciences. [source]

Fundamentplatten aus Stahlbeton und Stahlfaserbeton.

BETON- UND STAHLBETONBAU, Issue 9 2006
Experimentelle Untersuchungen zur Gebrauchstauglichkeit und Tragfähigkeit
Ein- und Mehrfamilienhäuser werden zunehmend statt auf Streifenfundamenten auf Fundamentplatten gegründet. Vorteile ergeben sich neben der wirtschaftlicheren Ausführung der Aushubarbeiten durch die einfachere Herstellung der Platte. Bei der Ausführung als Stahlfaserbetonplatte ergeben sich besonders wirtschaftliche Lösungen dann, wenn an die Gebrauchstauglichkeit keine besonderen Anforderungen wie Wasserdichtheit oder Rißbreitenbeschränkung gestellt werden. An der Fachhochschule Aachen wurden vergleichende experimentelle Untersuchungen an Bodenplatten aus Beton, Stahlbeton und Stahlfaserbeton unter Lastbeanspruchung durchgeführt. Es konnte nachgewiesen werden, daß Stahlfaserbeton für Fundamentplatten ein geeigneter Werkstoff ist, wenn Mindestanforderungen an die Steifigkeit des Bodens eingehalten werden. Bei erhöhten Anforderungen an die Gebrauchstauglichkeit werden Stahlbeton oder Kombinationen aus Stahlfaserbeton und Stahlbeton als sinnvoll erachtet, wenn diese auf Basis einer elastischen Schnittgrößenermittlung bemessen werden. Reinforced Concrete and Steel Fibre Reinforced Concrete Rafts Experimental tests on serviceability and ultimate loading performance Houses and residential buildings are increasingly built on rafts instead of strip foundations. The main advantages of rafts are more efficient excavation works and easy concreting of the rafts itself. The use of steel fibre reinforced concrete slabs offers economic advantages if there are no special requirements on service ability such as water tightness or crack limitations. At Aachen University of Applied Sciences a comparative experimental study on the load carrying behaviour of rafts made of concrete, reinforced concrete and steel fibre reinforced concrete was carried out. The tests have proven steel fibre concrete as suitable material for rafts in case of sufficient stiffness of the subbase. In case of special requirements on service ability, reinforced concrete or combined fibre and bar reinforced concrete should be used. In that case stresses should be calculated based on the elastic theory. [source]

Phenotype and Function of Somatic Primary Afferent Nociceptive Neurones with C-, A,- or A,/,-Fibres

EXPERIMENTAL PHYSIOLOGY, Issue 2 2002
S. N. Lawson
Nociceptive dorsal root ganglion (DRG) neurones have fibres that conduct in the C, A, and A,/, conduction velocity range. The properties of nociceptive compared with non-nociceptive somatic afferent dorsal root ganglion neurones appear to fall into two patterns, A and B. Pattern A properties of nociceptive neurones, the more common type, include longer action potential duration and slower maximum rate of fibre firing, as well as a greater expression of substance P and calcitonin gene-related peptide immunoreactivity. The values of pattern A properties appear to be graded according to the conduction velocity group (C, A, or A,/,) of the fibres. The most pronounced forms of A-type properties are expressed by nociceptive neurones with C-fibres, and these become less pronounced in nociceptive neurones with A,-fibres and least pronounced in those with A,/, fibres (C > A, > A,/,). Some of these properties are also expressed in a less extreme but similarly graded manner through C, A, and A,/, groups of non-nociceptive low threshold mechanoreceptive (LTM) neurone. The less common pattern B properties of nociceptive neurones have similar values in C-, A,- and A,/,-fibre nociceptive neurones but these clearly differ from LTM units with C-, A,- and A,/,-fibre conduction velocities. These features of nociceptive neurones include consistently larger action potential overshoots and longer after-hyperpolarisation durations in nociceptive than in LTM neurones. [source]

Fracture resistance of root filled molar teeth restored with glass fibre bundles

INTERNATIONAL ENDODONTIC JOURNAL, Issue 5 2010
F. B. Rodrigues
Rodrigues FB, Paranhos MPG, Spohr AM, Oshima HMS, Carlini B, Burnett LH Jr. Fracture resistance of root filled molar teeth restored with glass fibre bundles. International Endodontic Journal, 43, 356,362, 2010. Abstract Aim, To evaluate the effect of unidirectional or woven glass fibre tapes inserted into MOD cavity preparations on the fracture resistance of root filled molar teeth. Methodology, Extracted human molar teeth were randomly divided into six groups (n = 15) : G1 , sound teeth, control; G2 , MOD cavity preparation; G3 , MOD + root canal treatment (Endo); G4 , MOD + Endo + composite resin restoration (Resin); G5 , MOD + Endo + unidirectional fibre (UF) + Resin; G6 , MOD + ;Endo + woven fibre (WF) + Resin. The teeth were subjected to a compressive fracture test in a universal testing machine. After testing, two failure modes were classified: pulp chamber floor or cusp. Results, The highest and the lowest mean fracture strengths were found in sound teeth (G1) (4960N) and MOD + root canal treatment (G3) (612.84N), respectively, with significant differences from the other groups (P < 0.05). The remaining groups had statistically similar means. In G5 and G6, there was a tendency for fracture to occur in the pulp chamber floor compromising tooth integrity. Conclusions, The insertion of glass fibres into MOD cavity preparations and restoring them with composite resin was not different than molar teeth filled with composite resin only in terms of fracture resistance. Fibres placed into MOD cavities do not reinforce teeth. [source]

Fibres in the dough influencing freezing and thawing kinetics

INTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 1 2010
Jelena Filipovic
Summary Three types of commercial fibres were incorporated into the dough formula at the level of 0%, 5% and 10%. Dough freezing/thawing kinetics was determined at ,18 °C and +30 °C, respectively. Fibres type and quantity are influencing the slope of freezing curve not the trend of the freezing curve. Related to the control the presence of fibres in dough prevents the formation of the solid phase. Freezing/thawing process of dough is defined by the Fourier's equation and tested with three approximations. Experimental data correspond the best to unsteady temperature profile, with introduced value of t2 referring to the phase transformation, proved by determination coefficient. At freezing/thawing the highest determination coefficient is experienced with 10% of inulin GR (0.966 and 0.991), and the lowest with 10% of fibrex (0.939 and 0.972). Pertinent data point at the possibility of mathematical interpretation of freezing/thawing processes that is of a particular interest for the bakery practice. [source]

Distribution of Corticotropin-Releasing Factor Binding Protein-Immunoreactivity in the Rat Hypothalamus: Association With Corticotropin-Releasing Factor-, Urocortin 1- and Vimentin-Immunoreactive Fibres

JOURNAL OF NEUROENDOCRINOLOGY, Issue 3 2005
B. A. Henry
Abstract Corticotropin-releasing factor binding protein (CRF-BP) is a 37-kDa protein with high affinity binding sites for both corticotropin-releasing factor (CRF) and urocortin 1. Previous studies have examined the distribution of CRF-BP mRNA and peptide within the central nervous system. Due to the predominant cortical localisation, very little is known about CRF-BP in subcortical structures including the hypothalamus. The present study employed immunohistochemistry to characterise the distribution of CRF-BP-like-immunoreactive (-ir) cells and fibres in the rat hypothalamus. Bipolar and multipolar CRF-BP-ir neurones were scattered throughout the rostro-caudal extent of the hypothalamus. Distinct clusters of CRF-BP-ir neurones were identified in the anterior and posterior parvocellular and dorsal cap subdivisions of the paraventricular nucleus (PVN), as well as in the dorsal hypothalamic area, dorsomedial hypothalamic nucleus (DMN), ventral premammillary nucleus and zona incerta. CRF-BP-ir fibres extending from the third ventricle were found in the mediobasal hypothalamus and within the arcuate nucleus-median eminence region. Double immunostaining together with confocal microscopy demonstrated that the CRF-BP-immunostained fibres within the mediobasal hypothalamus coincided with vimentin immunostaining indicating that CRF-BP-ir is present within tanycytes. To define the relationship between CRF-BP-ir cells and endogenous ligands for CRF-BP, double immunohistochemistry was performed to examine possible sites within the hypothalamus where CRF- or urocortin 1-ir fibres innervate regions that contain CRF-BP-ir cell bodies. CRF-BP-ir cell bodies typically coincided with dense CRF-ir, but not urocortin 1-ir fibre innervation. CRF-ir fibre innervation was moderate to high within the anterior and posterior parvocellular subdivisions of the PVN, the dorsal cap of the PVN, DMN and the zona incerta; all regions that contained CRF-BP-ir cell populations. These studies demonstrate that, within the hypothalamus, CRF-BP-ir cells and fibres are concentrated within a circuitry known to be involved in mediating neuroendocrine and autonomic responses to stress. [source]

A Novel Concept for Highly Oriented Carbon Nanotube Composite Tapes or Fibres with High Strength and Electrical Conductivity

MACROMOLECULAR MATERIALS & ENGINEERING, Issue 11 2009
Hua Deng
Abstract A new concept is described for the creation of multifunctional polymer nanocomposite tapes (or fibres) that combines high stiffness and strength with good electrical properties and a low percolation threshold of carbon nanotubes (CNTs). The concept is based on a bicomponent tape (or fibre) construction consisting of a highly oriented polymer core and a conductive polymer composite (CPC) skin based on a polymer with a lower melting temperature than the core, enabling thermal annealing of these skins to improve conductivity through a dynamic percolation process while retaining the properties of the core and hence those of the tape (or fibre). The percolation threshold in the CPC skins of the highly drawn conductive bicomponent tapes could be decreased from 5.3 to 1.1,wt.-% after annealing. [source]

Dietary Fibres and Human Health

MOLECULAR NUTRITION & FOOD RESEARCH (FORMERLY NAHRUNG/FOOD), Issue 6 2005
Lynnette R. Ferguson
[source]

Asymmetric Polymer Bridging Between Starch-Coated Colloidal Particles and Pulp Fibres by Cationic Polyacrylamide

THE CANADIAN JOURNAL OF CHEMICAL ENGINEERING, Issue 5 2007
Agatha Poraj-Kozminski
Abstract Internal sizing agents are commonly used as additives in papermaking to impart hydrophobicity to paper. They are commonly added in the form of colloidal particles, stabilized by cationic starch. As an example we studied the deposition of micron-sized Alkyl Ketene Dimer (AKD) particles on pulp fibres by cationic polyacrylamide (cPAM), a common flocculent. It was found that cPAM did not adsorb on AKD particles stabilized by cationic starch. Despite this inability to adsorb, cPAM was found to drastically improve the deposition of AKD particles on pulp fibres. This deposition was ascribed to asymmetric polymer bridging, a phenomenon observed by us before, while studying clay deposition on fibres by polyethylene oxide. In asymmetric polymer bridging between two types of particles, the bridging polymer first adsorbs on one type of particle, since it is unable to adsorb on the second type. Asymmetric polymer bridging occurs when the enthalpy gain on both surfaces exceeds the entropy loss. The kinetics of AKD deposition on fibres was found to agree with the predictions of the asymmetric bridging theory. In addition, an increase in bond strength with time was found, due to starch and cPAM reconfiguration. The increase in AKD retention by cPAM is also observed in experiments on a laboratory twin-wire sheet former. Asymmetric polymer bridging by cPAM between starch-coated AKD particles and fibres is compared with classical polymer bridging by cPAM between fibres and AKD particles coated by carboxymethylcellulose. Des agents d'encollage internes sont communément utilisés comme additifs dans la fabrication du papier pour transmettre l'hydrophobicité au papier. Ils sont communément ajoutés sous la forme de particules colloïdales, stabilisées par l'amidon cationique. À titre d'exemple, on a étudié la déposition de particules microniques de dimère de cétène d'alkyle (AKD) sur des fibres de pâte par le polyacrylamide cationique (cPAM), un floculant commun. On a trouvé que le cPAM ne s'adsorbait pas sur les particules d'AKD stabilisées par l'amidon cationique. Malgré cette incapacité à s'adsorber, on a trouvé que le cPAM améliorait considérablement la déposition des particules d'AKD sur les fibres de pâte. Cette déposition est imputée au pontage de polymères asymétriques, un phénomène que nous avons observé précédemment, lors de l'étude de la déposition d'argile sur les fibres par l'oxyde de polyéthylène. Dans le pontage de polymères asymétriques entre deux types de particules, le polymère de pontage s'adsorbe d'abord sur un type de particules, vu qu'il est incapable de s'adsorber sur le second type de particules. Le pontage de polymères asymétriques survient lorsque le gain d'enthalpie sur les deux surfaces excède la perte d'entropie. On a trouvé que la déposition d'AKD sur les fibres concordait avec les prédictions de la théorie de pontage asymétrique. En outre, on a observé une augmentation de la force de liaison dans le temps, en raison de la reconfiguration de l'amidon et du cPAM. L'augmentation de la rétention de l'AKD par le cPAM est également observée dans les expériences sur un appareil de formage de feuilles à double toile de laboratoire. Le pontage de polymères asymétriques par le cPAM entre les particules d'AKD enduites d'amidon et les fibres est comparé au pontage de polymères classique par le cPAM entre les fibres et les particules d'AKD enduites de carboxyméthylcellulose. [source]

Iron, Manganese and Copper Equilibria with Wood Fibres in Single Salt Aqueous Suspensions

THE CANADIAN JOURNAL OF CHEMICAL ENGINEERING, Issue 3 2005
Robin Susilo
Abstract Ions of Fe, Mn and Cu were introduced into suspensions of protonated or metal-free fibres and the equilibrium concentration of each metal in the fibre and surrounding solution was measured. The results were compared with the Donnan equilibrium model. Mn and Cu concentrations on the fibres were found to be pH dependent and in agreement with the model. An increased amount of Fe on the Kraft pulp fibres was found and attributed to iron containing precipitates trapped within the fibres. Precipitates in mechanical pulps had a very small amount (1-2 wt%) of iron. Des ions de Fe, Mn et Cu ont été introduits dans des suspensions de fibres protonatées ou « sans métaux » et la concentration d'équilibre de chaque métal dans la fibre et la solution environnante a été mesurée. Les résultats ont été comparés avec le modèle d'équilibre de Donnan. On a trouvé que les concentrations de Mn et Cu sur les fibres étaient dépendantes du pH et en accord avec le modèle. Une quantité accrue de Fe a été trouvée sur les fibres de pâte kraft et attribuée aux précipitats contenant du fer retenus dans les fibres. Les précipitats dans les pâtes mécaniques ont une très petite quantité (1-2% en poids) de fer. [source]

Influence of ionic strength on the time course of force development and phosphate release by dogfish muscle fibres

THE JOURNAL OF PHYSIOLOGY, Issue 3 2005
Timothy G. West
We measured the effects of ionic strength (IS), 200 (standard) and 400 mmol l,1 (high), on force and ATP hydrolysis during isometric contractions of permeabilized white fibres from dogfish myotomal muscle at their physiological temperature, 12°C. One goal was to test the validity of our kinetic scheme that accounts for energy release, work production and ATP hydrolysis. Fibres were activated by flash photolysis of the P3 -1-(2 nitrophenyl) ethyl ester of ATP (NPE-caged ATP), and time-resolved phosphate (Pi) release was detected with the fluorescent protein MDCC-PBP, N -(2[1-maleimidyl]ethyl)-7-diethylamino-coumarin-3-carboxamide phosphate binding protein. High IS slowed the transition from rest to contraction, but as the fibres approached the isometric force plateau they showed little IS sensitivity. By 0.5 s of contraction, the force and the rate of Pi release at standard and high IS values were not significantly different. A five-step reaction mechanism was used to account for the observed time courses of force and Pi release in all conditions explored here. Only the rate constants for reactions of ATP, ADP and Pi with the contractile proteins varied with IS, thus suggesting that the actin,myosin interactions are largely non-ionic. Our reaction scheme also fits previous results for intact fibres. [source]

Relationship of Birth Weight with the Size, Number and Proportion of Fibres in the Pig Semitendinosus Muscle

ANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 4 2009
F. Tristán
Summary The objective of this study was to determine the relationship between body weight and the size, number and proportion of muscle fibre types in the pig semitendinosus muscle at birth. Based on weight at birth, 68 specimens selected from 21 different litters from the same farm were allotted in two equal groups (G1 and G2). G1 included 34 piglets ,1.1 kg and G2 34 pigs ,2 kg. Fifteen piglets per group were killed at birth and the remaining 19 piglets in each group were reared until weaning (21 days) and post-weaning (67 days). The weight and total cross-sectional area of the semitendinosus muscle were recorded at birth. Then, type I and type II fibres from the superficial portion of the muscle were identified according to histochemistry and immunohistochemistry techniques and percentages, average size of each fibre type, and the total number of muscle fibres were estimated by morphometry. Birth weight in G1 was 54.74% lower than that in G2. Correspondingly, the total cross-sectional area of the semitendinosus, as well as the size and number of muscle fibres, was significantly lower in G1 (P < 0.001). Weight at birth still influenced weights at weaning and post-weaning, hence it was 43.17% and 28.38% lower respectively in G1. It is concluded that pig weight at birth is associated with muscle cellularity of the semitendinosus muscle of pig, which may influence the postnatal muscle growth and final size of muscle fibres and meat quality. [source]

Development of Galanin-Containing Nerve Fibres in Rat Tibia

ANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 2 2009
M. Gajda
Summary Galanin exerts tonic inhibition of nociceptive input to the central nervous system. Recently, this peptide was demonstrated in several neuronal and non-neuronal structures in bones and joints. In this study, the time of appearance and topographic localization of galanin-containing nerve fibres in bone were studied in rats from gestational day 16 (GD16) to postnatal day 21 (PD21). The tibia was chosen as a model of developing long bone and indirect immunofluorescence combined with confocal laser scanning microscopy was used to identify galanin-immunoreactive (GAL-IR) nerve fibres. The earliest, sparse GAL-IR fibres were observed on GD21 in the perichondrium of both epiphyses and in the periosteum of the diaphysis. From PD1 onwards, GAL-IR fibres were also seen in the bone marrow cavity and in the region of the inter-condylar eminence of the knee joint. Intramedullary GAL-IR fibres in proximal and distal metaphyses appeared around PD1. Some of them accompanied blood vessels, although free fibres were also seen. GAL-IR fibres located in the cartilage canals of both epiphyses were observed from PD7, in the secondary ossification centres from PD10 and in the bone marrow of both epiphyses from PD14. The time course and localization of galanin-containing nerve fibres resemble the development of substance P- and CGRP-expressing nerve fibres, thus suggesting their sensory origin. [source]

The Effect of Testosterone on Gastrocnemius Muscle Fibres in Growing and Adult Male and Female Rats: A Histochemical, Morphometric and Ultrastructural Study,

ANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 2 2003
. Üstünel
Summary In this study, the effect of testosterone on gastrocnemius muscle fibres in growing and adult rats (male and female) was examined using histochemical, morphometric and ultrastructural techniques. After physiological saline (PS), olive oil (OvO) or olive oil + testosterone (OvOT) injections on 72 rats (growing and mature, 36 male and 36 female), the sample tissues of fibre types of the gastrocnemius muscle taken were examined by histochemical [alkaline adenosine triphosphatase (alk-ATPase), acid ATPase (ac-ATPase)], morphometric and ultrastructural techniques. In PS-injected control groups, the gastrocnemius muscle of both sexes contained all the fibre types studied [slow-oxidative muscle fibres (type I), fast-oxidative glycolytic muscle fibres (type IIA) and fast-glycolytic muscle fibres (type IIB)]. The type I fibres had the smallest diameter, type IIA had a medium diameter and type IIB fibres had the largest diameter. In OvO-injected groups, it was observed that the OvO had little effect on the gastrocnemius muscles of either sex, although there was significant enlargement of type IIB fibres. After the injection of OvOT, hypertrophy of muscle fibres was determined by morphometric study. The biggest increase in diameter was on type I fibres. In addition, degenerations on some mitochondria, accumulation of lipid droplets on type I and type II fibres, an increase in glycogen particles, bifurcation of myofibrils, an increase in the number and diameter of units resembling T tubules and an increase in ribosomal content were also observed in the same group by transmission electron microscope. Consequently, it was determined that testosterone can induce protein synthesis in gastrocnemius muscle fibres, and induces changes in shape and size, and also can change the appearance and the number of fibres. [source]

Sowing density and harvest time affect fibre content in hemp (Cannabis sativa) through their effects on stem weight

ANNALS OF APPLIED BIOLOGY, Issue 2 2009
W. Westerhuis
Abstract Sowing density and harvest time are considered important crop management factors influencing fibre quantity and quality in hemp (Cannabis sativa). We investigated whether the effects of these factors are essentially different or that both factors affect stem weight and thereby total and long-fibre content. The effects of all combinations of three sowing densities and three harvest times were studied for six different stem parts. Almost 500 samples consisting of stem parts from 50 plants and with a length of 50 cm were tested. Fibres were extracted by a controlled warm-water retting procedure, followed by breaking and scutching. The initial sample weight was fractionated into retting losses, wood, tow and long fibre. In both Italy and the Netherlands, crops were successfully established with different stem densities (99,283 m,2), plant heights (146,211 cm) and stem diameters (4.5,8.4 mm) at harvest. Stem dry matter yields (6.8,11.7 Mg ha,1) increased with a delay in harvest time but were not affected by sowing density. Retting loss percentages were lower in lower stem parts and decreased with later harvest because maturation was associated with increasing amounts of fibre and wood. Within a certain stem part, however, the absolute retting losses were constant with harvest time. Multiple linear regression analyses showed that the amount of fibre in a hemp stem is almost completely determined by the weight and the position of that stem part. When the plant grows, the increase in dry matter is split up into fibres and wood in a fixed way. This total fibre/wood ratio was highest in the middle part of the stem and lower towards both bottom and top. Sowing density and harvest time effects were indirect through stem weight. The long-fibre weight per stem increased with the total fibre weight and hence with stem weight. Stem weight increased with harvest time; as harvest time did not affect plant density, the highest long-fibre yields were obtained at the last harvest time. The long fibre/total fibre ratio was lowest in the bottom 5 cm of the stems but similar for all other parts. Sowing density and harvest time effects again were indirect. Fibre percentages in retted hemp decreased with increasing stem weights towards a level that is presumably a variety characteristic. The dry matter increase between harvests, however, is much more important with respect to total and long-fibre yield. [source]

The anatomy of the perineal membrane: its relationship to injury in childbirth and episiotomy

AUSTRALIAN AND NEW ZEALAND JOURNAL OF OBSTETRICS AND GYNAECOLOGY, Issue 2 2002
Christopher N Hudson
ABSTRACT Background Episiotomy during childbirth, intended to protect the anal sphincter, may fail to do so. Furthermore damage to the anal sphincter complex may occur without complete perineal tear. We hypothesise that these particular injuries may occur due to posterior displacement of the anus leading to distraction of the anal sphincter complex from an anterior attachment to the perineal membrane. However, the anatomical basis for this has not been well defined. Objective To investigate the relationship between the anal sphincter and the perineal membrane. Materials and methods High-resolution MRI scans of a female cadaver perineum were performed. The imaging findings were correlated with the anatomical structure identified on dissection and histological examination. Results The perineal membrane was easily identified on MR imaging. Fibres from the perineal membrane could be seen to attach to the anal sphincter complex at the apex of the perineal body. This was confirmed on histological examination and was a deeper layer than that of the decussation of the superficial transverse perineal muscle with the superficial part of the external anal sphincter. Conclusion The upper ano-rectal canal and apex of the perineal body have demonstrable attachment to the free margin of the perineal membrane postero-lateral to the lower vagina. This attachment would resist posterior displacement of the anal canal. [source]

Innovative Katalysatoren zur oxidativen Dehydrierung in der Gasphase , Metallische Kurzfasern

CHEMIE-INGENIEUR-TECHNIK (CIT), Issue 6 2004
R. Brüning
Abstract Metallische Kurzfasern in ausgesuchter Legierungszusammensetzung und Gefügestruktur wurden auf ihre katalytische Aktivität bei der oxidativen Dehydrierung (ODH) von Propan zu Propen und von Isopropanol zu Aceton untersucht. Die über das Schmelzextraktions-Verfahren hergestellten Kurzfasern wurden einer intensiven Charakterisierung ihrer werkstoffseitigen Eigenschaften unterworfen. Dabei kamen lichtmikroskopische, DSC-, XRD-, REM- und EDX-Untersuchungen zum Einsatz, um Zusammenhänge zwischen der Werkstoffzusammensetzung, dem Gefüge und den katalytischen Eigenschaften zu ermitteln. Es werden ausgewählte Ergebnisse zur Temperaturabhängigkeit des Propan-Umsatzes bzw. der Propen-Selektivität präsentiert. So wurde Propen bei einem Propan-Umsatz von mehr als 50,% mit einer Ausbeute von 35,% gebildet. Auch die Selektivoxidation von Isopropanol zu Aceton erfolgte mit attraktiven Ausbeuten von über 80,%. Die Ergebnisse insgesamt belegen das hohe Innovationspotenzial der Metallfaserwerkstoffe. Innovative Catalysts for Oxidative Dehydration Reactions in the Gas Phase , Metallic Short Fibres The catalytic activity of metallic short fibres with chosen alloy composition and texture was investigated in the oxidative dehydration (ODH) of propane to yield propene, and of isopropanol to yield acetone. The short fibres were synthesised using a melt extraction process and the properties of the fibres were intensely characterised. A correlation between the structure and the catalytic activity of the material was established. Thus, light-optical microscopic-, DSC-, XRD-, REM- and EDX-methods were used to characterise the fibres. Selective results of the dependency of the temperature on the propane conversion are presented in this work. A yield of more than 35,% propene is obtained at a propane conversion of 50,%. The ODH of isopropanol to acetone occurred with attractive yields of over 80,%. The results demonstrate the high innovative potential of the metal fibre materials. [source]

ChemInform Abstract: Studies on Synthesis of 2-Methyl-3,1-benzoxazine-4(4H)-one Dyes and Their Application on Nylon and Polyester Fibres.

CHEMINFORM, Issue 16 2010
H. D. Navadiya
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

Functions of glutamate transporters in cerebellar Purkinje cell synapses

ACTA PHYSIOLOGICA, Issue 1 2009
Y. Takayasu
Abstract Glutamate transporters play a critical role in the maintenance of low extracellular concentrations of glutamate, which prevents the overactivation of post-synaptic glutamate receptors. Four distinct glutamate transporters, GLAST/EAAT1, GLT-1/EAAT2, EAAC1/EAAT3 and EAAT4, are distributed in the molecular layer of the cerebellum, especially near glutamatergic synapses in Purkinje cells (PCs). This review summarizes the current knowledge about the differential roles of these transporters at excitatory synapses of PCs. Data come predominantly from electrophysiological experiments in mutant mice that are deficient in each of these transporter genes. GLAST expressed in Bergmann glia contributes to the clearing of the majority of glutamate that floods out of the synaptic cleft immediately after transmitter release from the climbing fibre (CF) and parallel fibre (PF) terminals. It is indispensable to maintain a one-to-one relationship in synaptic transmission at the CF synapses by preventing transcellular glutamate spillover. GLT-1 plays a similar but minor role in the uptake of glutamate as GLAST. Although the loss of neither GLAST nor GLT-1 affects cerebellar morphology, the deletion of both GLAST and GLT-1 genes causes the death of the mutant animal and hinders the folium formation of the cerebellum. EAAT4 removes the low concentrations of glutamate that escape from uptake by glial transporters, preventing the transmitter from spilling over into neighbouring synapses. It also regulates the activation of metabotropic glutamate receptor 1 (mGluR1) in perisynaptic regions at PF synapses, which in turn affects mGluR1-mediated events including slow EPSCs and long-term depression. No change in synaptic function is detected in mice that are deficient in EAAC1. [source]

Changes in skeletal muscle size, fibre-type composition and capillary supply after chronic venous occlusion in rats

ACTA PHYSIOLOGICA, Issue 4 2008
S. Kawada
Abstract Aim:, We have previously shown that surgical occlusion of some veins from skeletal muscle results in muscle hypertrophy without mechanical overloading in the rat. The present study investigated the changes in muscle-fibre composition and capillary supply in hypertrophied muscles after venous occlusion in the rat hindlimb. Methods:, Sixteen male Wistar rats were randomly assigned into two groups: (i) sham operated (sham-operated group; n = 7); (ii) venous occluded for 2 weeks (2-week-occluded group; n = 9). At the end of the experimental period, specimens of the plantaris muscle were dissected from the hindlimbs and subjected to biochemical and histochemical analyses. Results:, Two weeks after the occlusion, both the wet weight of plantaris muscle relative to body weight and absolute muscle weight showed significant increases in the 2-week-occluded group (,15%) when compared with those in the sham-operated group. The concentrations of muscle glycogen and lactate were higher in the 2-week-occluded group, whereas staining intensity of muscle lipid droplets was lower in the 2-week-occluded group than those in the sham-operated group. The percentage of type I muscle fibre decreased, whereas that of type IIb fibre increased in the 2-week-occluded group when compared with the sham-operated group. Although the expression of vascular endothelial growth factor-188 mRNA increased, the number of capillaries around the muscle fibres tended to decrease (P = 0.07). Conclusion:, Chronic venous occlusion causes skeletal muscle hypertrophy with fibre-type transition towards faster types and changes in contents of muscle metabolites. [source]

Platelet activating factor (PAF) increases plasma protein extravasation and induces lowering of interstitial fluid pressure (Pif) in rat skin

ACTA PHYSIOLOGICA, Issue 1 2005
V. V. Iversen
Abstract Aim:, To investigate the ability of the microdialysis technique to measure capillary selectivity of different sized plasma proteins induced by local administration of platelet activating factor (PAF). Methods:, We used hollow plasmapheresis fibres with 3 cm membrane (cut off 3000 kDa) placed on the back of anaesthetized rats. Results:, Platelet activating factor (50 ,g mL,1) administered locally via the fibre, increased extravasation of radiolabelled 125I-HSA from plasma to the microdialysis fibre by approximately 900% compared both to baseline and the control fibre within 70 min (n = 6, P < 0.05). The extravasation in the control fibre did not change over time. HPLC measurement of plasma proteins in the microdialysis perfusate also demonstrated decreased capillary selectivity for proteins in the diameter range of 73 Å, 56 Å and 39 Å after local administration of PAF (n = 6, P < 0.05). PAF also significantly lowered interstitial fluid (Pif) pressure after subcutaneous administration (50 ,g mL,1). Mean arterial pressure (MAP) after intravenous injection of PAF (0.4 ,g kg,1) fell instantly by about 50 mmHg, and stabilized at 50 mmHg after 15 min (n = 6). MAP was unaltered when PAF was given through the microdialysis fibre (n = 4). Both total tissue water (TTW) and extravasation of albumin, measured as the plasma-to-tissue clearance (E-alb) showed a significant increase after PAF (n = 7, P < 0.05). Conclusions:, The present study demonstrates that PAF induces plasma protein extravasation and decrease capillary selectivity of different sized plasma proteins. It also increases transcapillary fluid flux, and lowers Pif, indicating a role for PAF in the interstitium for generation of transcapillary transport of water and large molecules followed by formation of oedema. [source]

Non-invasive monitoring of muscle blood perfusion by photoplethysmography: evaluation of a new application

ACTA PHYSIOLOGICA, Issue 4 2005
M. Sandberg
Abstract Aim:, To evaluate a specially developed photoplethysmographic (PPG) technique, using green and near-infrared light sources, for simultaneous non-invasive monitoring of skin and muscle perfusion. Methods:, Evaluation was based on assessments of changes in blood perfusion to various provocations, such as post-exercise hyperaemia and hyperaemia following the application of liniment. The deep penetrating feature of PPG was investigated by measurement of optical radiation inside the muscle. Simultaneous measurements using ultrasound Doppler and the new PPG application were performed to elucidate differences between the two methods. Specific problems related to the influence of skin temperature on blood flow were highlightened, as well. Results:, Following static and dynamic contractions an immediate increase in muscle perfusion was shown, without increase in skin perfusion. Liniment application to the skin induced a rapid increase in skin perfusion, but not in muscle. Both similarities and differences in blood flow measured by Ultrasound Doppler and PPG were demonstrated. The radiant power measured inside the muscle, by use of an optical fibre, showed that the near-infrared light penetrates down to the vascular depth inside the muscle. Conclusions:, The results of this study indicate the potentiality of the method for non-invasive measurement of local muscle perfusion, although some considerations still have to be accounted for, such as influence of temperature on blood perfusion. [source]

Partial reversal of conduction slowing during repetitive stimulation of single sympathetic efferents in human skin

ACTA PHYSIOLOGICA, Issue 3 2004
M. Campero
Abstract Aims:, To describe and identify the function of a class of human C fibre with an unusual response to repetitive electrical stimulation. Other C fibres slow progressively at 2 Hz (type 1), reach a latency plateau (type 2) or hardly slow at all (type 3). Methods:, C fibres innervating hairy skin were recorded by microneurography in the superficial peroneal nerves of 19 healthy volunteers. Baseline electrical stimulation of the skin was at 0.25 Hz, and activity-dependent slowing recorded during stimulation at 2 Hz for 3 min and after a 3-min pause in stimulation. Results:, In 41 units, there was a partial recovery of latency during repetitive stimulation. These were classified as ,type-4' units, and identified as sympathetic efferents, since they exhibited spontaneously activity, which was enhanced by manoeuvres that increase sympathetic outflow (15 of 16 cases) and/or suppressed by a proximal anaesthetic block (eight of eight cases). The peak slowing during 2 Hz trains averaged 6.47 ± 2.06% (mean ± SD, n = 41), but after 3 min the slowing had reduced to 4.90 ± 2.20%, which was less than in all type 1 (nociceptor) fibres but similar to that in type 2 (cold) fibres. Compared with cold fibres, type-4 sympathetic fibres slowed more after the first 10 impulses at 2 Hz (2.57 ± 0.45%) and also after a pause in stimulation (1.66 ± 0.51%). Conclusions:, The distinctive activity-dependent slowing profiles of these type-4 sympathetic C units may help identification in vitro, and suggest that hyperpolarization-activated channels have a particularly prominent role in the axonal membrane. [source]

Muscle fibre size and capillarity in Korean diving women

ACTA PHYSIOLOGICA, Issue 2 2003
K. A. Bae
Abstract Aim:, Effects of prolonged habitual cold-water immersion on fibre size and capillarity in vastus lateralis muscle were studied in human beings. The hypothesis tested in the present study was that cold acclimatized human skeletal muscle would have reduced muscle fibre size and higher capillarity, favouring the idea of efficacy of recruitment under cold environment. Methods:, Ten women breath-hold divers (BHDs) and 10 active women (controls CONs) participated in this study. Muscle biopsy was obtained from vastus lateralis and determined fibre type composition and capillary density. Results: A major finding was that all BHDs revealed a markedly smaller cross-sectional area (CSA) in all fibre types than the CONs, or even than any other morphological data reported in previous investigations. Furthermore, mean CSA of type II fibre (range 1205,2766 ,m2) was much smaller than type I fibre (2343,4327 ,m2). The number of capillaries per fibre in different fibre types in the BHDs was higher than in the CONs (P < 0.001), and diffusional area was smaller in type II fibres than in type I fibres (P < 0.001). The BHDs and the CONs have similarity in the percentage of type I fibres, but type II fibre was predominant in both groups. Interestingly the proportion of type IIx fibre in the BHDs was higher (31%) than in the CONs (22%). No significant difference was found in the thigh circumference between the groups. Conclusion:, The present study demonstrates that prolonged habitual cold-water immersion may induce a decrease in fibre size and an increase in capillarity in human skeletal muscle. [source]

The characterization of Tasmanian devil Sarcophilius harrisii pelage fibres and their associated lipids

ACTA ZOOLOGICA, Issue 4 2009
J. S. Church
Abstract The Tasmanian devil (Sarcophilius harrisii) is the largest living marsupial carnivore left on Earth. In this paper we report the results of the first thorough characterization of the keratin fibres comprising the Tasmanian devil pelage. The fibre's morphology, structure, composition and surface have been investigated. The results have been compared with those of a number of other mammalian species including carnivores and herbivores. The fibres structure was found to be consistent with that expected for a keratin fibre. From the results of the bound lipid analysis it can be concluded that the Tasmanian devil is a typical mammal in which the 21-carbon atom anteiso branched fatty acid is the predominant bound fatty acid. This is consistent with the Tasmanian devil's position in the mammalian phylogenetic tree. The amino acid analysis places the devil in line with other carnivores. The high cystine and proline content may correlate with the Tasmanian devil's diet which is rich in muscle and collagen proteins. [source]

Sperm ultrastructure of the Brazilian Amazon poison frogs Epipedobates trivittatus and Epipedobates hahneli (Anura, Dendrobatidae)

ACTA ZOOLOGICA, Issue 1 2004
Odair Aguiar-Jr
Abstract The sperm ultrastructure of Epipedobates trivittatus and E. hahneli is described. The spermatological characteristics are identical in both species, except for the extension of the acrosomal vesicle. The structure of the acrosomal complex is shared with species of the Bufonoidea neobatrachian lineage, which differs from the condition observed in species included in the ranoid lineage. The phylogenetic significance of the mitochondrial collar, also seen in Eubufonoidea groups, is still unclear. Also the significance of the alternative mitochondrial arrangement seen here is unclear. The perpendicular arrangement of the centrioles is also shared with the Bufonoidea and is considered a synapomorphic condition. An expanded undulating membrane and the absence of a juxtaxonemal fibre appear to be apomorphic characteristics of dendrobatid species, as also observed (homoplastically) for species of Litoria and Cyclorana. However, the notable expansion of the undulating membrane appears to be an autapomorphy of Dendrobatidae frogs. The ultrastructural data presented here do not support the proposed placement of E. trivittatus in a separate genus. [source]