Showing papers by "Katholieke Universiteit Leuven published in 1972"
TL;DR: Experimental analysis of the Quadriceps Muscle Force and Patello-Femoral Joint Reaction Force for Various Activities and its implications for clinical practice are described.
Abstract: (1972). Experimental Analysis of the Quadriceps Muscle Force and Patello-Femoral Joint Reaction Force for Various Activities. Acta Orthopaedica Scandinavica: Vol. 43, No. 2, pp. 126-137.
420 citations
TL;DR: Lauwerynset et al. as mentioned in this paper investigated the occurrence throughout the intrapulmonary airways of intramucosal corpuscles or so-called Neuroepithelial Bodies, composed of more or less parallely oriented, non-ciliated cylindrical cells which reach from the basement membrane to the airway lumen and display a prominent cytoplasmic argyrophilia, a less pronounced argentaffinity and an intense yellow fluorescence.
Abstract: Lungs of fetal, neonatal and adult rabbits and of various other adult mammals were investigated. Several routine and silver staining methods, Falck's fluorescent amine technic and various electron microscopic techniques were performed. As in the human infant lung (Lauwerynset al., 1972) each of these techniques revealed the occurrence throughout the intrapulmonary airways of intramucosal corpuscles or so-called Neuroepithelial Bodies, composed of more or less parallely oriented, non-ciliated cylindrical cells which reach from the basement membrane to the airway lumen and display a prominent cytoplasmic argyrophilia, a less pronounced argentaffinity and an intense yellow fluorescence. Ultrastructurally, they are granulated, containing mainly two types of dense-cored vesicles of which the first type exhibits a positive reaction for serotonin (technic of Jaim-Etcheverryet al., 1968). They contain intracorpuscular nerve endings which form synaptic end formations upon the granulated cells. Though the functions of these serotonin producing Neuroepithelial Bodies remain furthermore unsettled, they seem to be related also to the recently reported AFG (Argyrophil, Fluorescent and Granulated) cells (Lauwerynset al., 1969, 1970a) and might be involved in various mucosal bronchial and bronchiolar neurosecretory processes; most probably they are chemo-, stretch- and/or tactile neuroreceptor organs modulated by the central nervous system.
229 citations
TL;DR: The enzyme activities found were higher than values reported in the literature for untreated or purified preparations from rat liver, and were above reported values of the maximal biliary excretion rate of bilirubin.
Abstract: 1. The bilirubin UDP-glucuronyltransferase assay described by Van Roy & Heirwegh (1968) has been improved. 2. Extraction of final azo-derivatives is rendered more simple and efficient by thorough emulsification and by cooling. 3. Pretreatment of homogenates and cell fractions with digitonin increases the sensitivity of the assays and gives less variable results than those with untreated preparations. The activation procedure is flexible. 4. Blank values (obtained from incubation mixtures from which activating bivalent metal ion and UDP-glucuronic acid were omitted) are low. No endogenous conjugate formation could be detected except with untreated, fresh liver homogenates. Control incubation mixtures containing the latter preparations are preferably kept at 0°C. 5. With activated microsomal preparations, rates of breakdown of UDP-glucuronic acid (as monitored by release of Pi) were low. Little if any increase in enzyme activity was found when UDP-N-acetylglucosamine was included in the incubation mixtures. 6. Slight deviation from Michaelis–Menten kinetics with respect to bilirubin observed at low substrate concentrations is probably related to the use of binding protein in the assay mixtures. Michaelis–Menten kinetics were followed with respect to UDP-glucuronic acid. Part of the enzyme in microsomal preparations from rat liver functioned independently of added bivalent metal ions. Mn2+ was slightly more, and Ca2+ somewhat less, stimulatory than Mg2+. The Mg2+-dependent fraction showed Michaelis–Menten kinetics with respect to the added Mg2+. 7. The enzyme activities found were higher than values reported in the literature for untreated or purified preparations from rat liver. They were above reported values of the maximal biliary excretion rate of bilirubin.
218 citations
TL;DR: Routine staining methods and Jabonero's silver impregnation revealed groups of cells which are distinct from the surrounding epithelium by their light optical and their histochemical properties and which have been named “Neuroepithelial Bodies.”
Abstract: Tissue sections of 15 lungs from human infants were taken immediately after death. In each case, routine staining methods and Jabonero's silver impregnation, modified by Van Campenhout, were performed. Cathecholamines were traced according to Falck's method. Each of these techniques revealed in the bronchial and bronchiolar mucosa spherical to ovoid groups of cells, which are distinct, from the surrounding epithelium by their light optical and their histochemical properties and which have been named “Neuroepithelial Bodies.”
The Neuroepithelial Body bulges into the corium and is built up of cells with a clear cytoplasm and a rounded nucleus. Its apical part protrudes into the bronchial and bronchiolar lumen mostly above the level of the ciliated cell lining and consists of small non-ciliated cuboidal cells. After silver impregnation, they display a granular silver deposit, especially in the basal cells and appear to be innervated. The technique of Falck reveals a white to yellow fluorescence, especially in the basal area where also the argyrophilia is most marked.
The functions of these corpuscular, argyrophilic, innervated and fluorescent bronchial and bronchiolar Neuroepithelial Bodies remain unsettled. Though a separate entity, they seem to be related to the recently reported bronchial Argyrophil, Fluorescent and Granulated AFG (peptide and amine producing?) cells. They might be involved in mucosal bronchial and bronchiolar neurosecretory processes; most probably, however, they are chemo-, stretch-, and/or tactile neuro-receptor organs.
202 citations
TL;DR: Although placental infarction is apparently a direct result of the occlusive hypertensive lesions in the spiral arteries, it is also to be considered as the ultimate evidence of failure of adequate placentation.
184 citations
TL;DR: The results are interpreted by assuming that even during spike discharge the Ca-permeability of the membrane is very small and that this entering calcium could function as a trigger, releasing intracellularly localized calcium, which should be distinguished from the important uptake of calcium occurring during K-depolarization.
Abstract: The calcium distribution in smooth muscle cells of the taenia coli has been studied with a method based on the action of lanthanum ions. La3+-ions make it possible to separate the extracellular calcium from the cellular calcium by their high affinity for extracellular calcium binding sites and by their blocking action on the transmembrane calcium movements. Using this method the cellular calcium content and its exchangeable fraction have been determined. In spontaneously active tissues the exchange of the cellular calcium reaches a maximal value of 108 μM/kg wet wt or 1/6 of the total cellular calcium, while in quiescent tissues (treated with D600) this maximal value is 80 μM/kg wet wt.
132 citations
TL;DR: The metabolism of human fibrinogen, labelled with radioactive iodine, was studied in 35 healthy subjects over a 5 yr period using eight fibrinolytic system with tranexamic acid preparations in 23 labelling procedures.
Abstract: Summary
The metabolism of human fibrinogen, labelled with radioactive iodine, was studied in 35 healthy subjects over a 5 yr period using eight fibrinogen preparations in 23 labelling procedures. The labelled fibrinogen was highly clottable and homogeneous on agarose gel filtration, immunoelectrophoresis and auto-radiography. Results in the control subjects were: plasma volume 42 ± 7 ml/kg; plasma fibrinogen concentration 284 ± 71 mg/100 ml; total plasma fibrinogen pool 119 ± 40 mg/kg, representing 0.72 ± 0.07 of the total body pool; fibrinogen half-life 4.14 ± 0.56 days; fractional catabolic rate 0.24 ± 0.04 of the plasma pool/day; fractional transcapillary efflux rate 0.60 ± 0.26 of the plasma pool/day. Comparable results were obtained for all labelled fibrinogen batches. Anticoagulation with heparin in five control subjects had no influence on the fibrinogen half-life. Inhibition of the fibrinolytic system with tranexamic acid in five control subjects had no influence on the fibrinogen half-life in four of them but resulted in a prolongation in one subject.
A mathematical compartmental model for the metabolism of fibrinogen is proposed, consisting of one extra vascular compartment and three catabolic pathways (basic protein turnover, intravascular fibrin formation, and intravascular fibrino(geno)lysis). In physiological conditions intravascular fibrin formation or fibrino(geno)lysis are not essential in the fibrinogen turnover.
121 citations
TL;DR: Using thin-layer chromatography, gas-liquid chromatography and mass spectrometry, trihydroxycoprostanic acid was identified in the duodenal fluid of 2 subjects with anomalies of the intrahepatic bile ducts and its excretion was due to a reduced capacity of the hepatocytes to split off the 3 terminal carbon atoms of the side chain of triHydroxyprostanic Acid.
118 citations
TL;DR: In this paper, a review of the information derived from transmission electron microscopy indicates the presence of various anomalous contrast and diffraction effects in quenched beta-phase alloys.
Abstract: Quenched beta-phase alloys in systems based on the noble metals are often thermodynamically metastable. A review of the information derived from transmission electron microscopy indicates the presence of various anomalous contrast and diffraction effects in such alloys. Contrast effects may be referred to as mottling, striation, cross-hatching, etc., and they may change in intensity with respect to different extinction contours, foil thickness and foil tilting. Diffraction effects refer to diffuse streaking in certain directions, the appearance of additional maxima or their splitting, and slight deviations from cubic symmetry. The possible causes for the presence of such features are discussed in the present paper. Some effects are considered to be at least in part the result of surface rippling, caused by electropolishing, but other effects are associated with the presence of precipitates, or with atomic displacements from ideal bcc packing. A detailed analysis of the diffraction effects suggests that structural features must be present analogous to the hexagonal ω-phase (known in transition alloys), and the nearly hexagonal α′ phase (known in bainitic structures). The stability of the beta-phase alloys is considered in terms of the above features, concluding that both vibrational and electronic entropy terms may be contributing, and that instability at low temperatures may be manifested in a number of ways not all of which fit into conventional phase-transformation categories.
80 citations
TL;DR: Heat treatment of Phycomyces sporangiospores, which breaks dormancy, causes a very rapid 10- to 15fold increase in trehalase activity; soon after the heat shock the enzyme activity decays and the possible role of tre Halase in the spore-activation process is discussed.
Abstract: Heat treatment of Phycomyces sporangiospores, which breaks dormancy, causes a very rapid 10- to 15fold increase in trehalase activity; soon after the heat shock the enzyme activity decays. This phenomenon can be repeated several times by repeating the heat shocks. Prolonging the heat treatment over the minimum required time delays the decay of enzyme activity. Cycloheximide does not prevent the rise in enzyme activity. It is suggested that heat treatment converts temporarily an inactive form of trehalase into an active one. Optimal enzyme activity is obtained at pH 7.5 and the enzyme requires metal ions for maximal activity. The possible role of trehalase in the spore-activation process is discussed.
63 citations
TL;DR: The ultrastructural characteristics of the pancreatic islets was studied in seven surgical specimens of human pancreas and the effects of two different fixation methods were compared: osmium tetroxide alone and glutaraldehyde followed by Osmium.
TL;DR: The state of the art to date is given, as well as to poinit out potential future courses of development, in the various solutions that have been proposed for the resource-constrained project scheduling problem.
Abstract: It is the purpose of this article to review the various solutions that have been proposed for the resource-constrained project scheduling problem. An attempt is made to give the state of the art to date, as well as to poinit out potential future courses of development. Emphasis is placed on the basic approach involved in each technique rather than on the computational steps required to obtain a solution. In principle the review is limited to solution techniques described in the literature; other important work will be treated also, as far as it is known to the author.
TL;DR: In this article, the electrostatic surface energy of the upper layer of ZnO was calculated to be 0.071 Z2e2/a, and the stability criterion was verified by an intrinsic surface state mechanism.
Abstract: LEED studies on the polar surfaces of ZnO showed a rather stable (1 × 1) pattern on both the surfaces when cleaved in ultra high vacuum at liquid nitrogen temperature or at room temperature; on those surfaces the stability criterion is verified by an intrinsic surface state mechanism. Preannealing of real surfaces in oxygen (6 h, 600 °C, 760 Torr) causes a (√3 × √3) pattern; on the (0001) surfaces oxygen is chemisorbed while on the (0001) faces it takes part in stabilising the surface. The electrostatic surface energy of this upper layer of oxygen is calculated to be 0.071 Z2e2/a.
TL;DR: In this paper, a conventional absolute method was used for the measurement of the thermal conductivity of pressed and sintered p-type Bi2Te3-Sb2Te-3-Bi2Se3 alloys in the temperature range of 300 to 600 K. The measurements were made in directions parallel and perpendicular to the pressing direction, and the maximum values of the figure of merit for the p- and n-type samples were 17 × 10−1 and 16 × 10 −4 K−1, respectively.
Abstract: A conventional absolute method was used for the measurement of the thermal conductivity of pressed and sintered p-type Bi2Te3–Sb2Te3–Sb2Se3 alloys and n-type Bi2Te3–Bi2Se3 alloys in the temperature range of 300 to 600 K. The measurements were made in directions parallel and perpendicular to the pressing direction. Measurements of the Seebeck coefficient and the electrical resistivity for these alloys were performed between 300 and 575 K in the pressing direction only. The maximum values of the figure of merit for the p- and n-type samples are 17 × 10−1 and 16 × 10−4 K−1, respectively. It is concluded that a thermoelectric generator, having these alloys for its p- and n-branches will attain its highest efficiency in the temperature range between 370 and 480 K.
Die thermoelektrischen Eigenschaften von gepresten und gesinterten p-leitenden Bi2Te3–Sb2Te3–Sb2Se3 und n-leitenden Bi2Te3–Bi2Se3 Legierungen wurden im Temperaturbereich 300 bis 600 K mit einer konventionellen Methode untersucht. Diese Messungen wurden parallel und senkrecht zur Presrichtung durchgefuhrt. Der Seebeckkoeffizient und der elektrische Widerstand dieser Legierungen wurden im Temperaturbereich 300 bis 575 K nur in Presrichtung gemessen. Die Maximalwerte der Leistungsfaktoren von p- und n-leitenden Proben betragen 17 × 10−4 bzw. 16 × 10−4 K−1. Daraus folgt, das ein thermoelektrischer Generator mit diesen Legierungen als p- bzw. n-Zweig seine hochste Leistungsfahigkeit im Temperaturbereich 370 bis 480 K erreicht.
TL;DR: Digitonin-treated and untreated homogenates, cell extracts and washed microsomal preparations from liver of Wistar R rats are capable of transferring sugar from UDP-glucose or UDP-xylose to bilirubin.
Abstract: 1. Digitonin-treated and untreated homogenates, cell extracts and washed microsomal preparations from liver of Wistar R rats are capable of transferring sugar from UDP-glucose or UDP-xylose to bilirubin. No formation of bilirubin glycosides occurred with UDP-galactose or d-glucose, d-xylose or d-glucuronic acid as the sources of sugar. 2. Procedures to assay digitonin-activated and unactivated bilirubin UDP-glucosyltransferase and bilirubin UDP-xylosyltransferase were developed. 3. In digitonin-activated microsomal preparations the transferring enzymes had the following properties. Both enzyme activities were increased 2.5-fold by pretreatment with digitonin. They were optimum at pH6.6-7.2. Michaelis-Menten kinetics were followed with respect to UDP-glucose. In contrast, double-reciprocal plots of enzyme activity against the concentration of UDP-xylose showed two intersecting straight-line sections corresponding to concentration ranges where either bilirubin monoxyloside was formed (at low UDP-xylose concentrations) or where mixtures of both the mono- and di-xyloside were synthesized (at high UDP-xylose concentrations). Both enzyme activities were stimulated by Mg(2+); Ca(2+) was slightly less, and Mn(2+) slightly more, stimulatory than Mg(2+). Of the activities found in standard assay systems containing Mg(2+), 58-78% (substrate UDP-glucose) and 0-38% (substrate UDP-xylose) were independent of added bivalent metal ion. Double-reciprocal plots of the Mg(2+)-dependent activities against the concentration of added Mg(2+) were linear. 4. In comparative experiments the relative activities of liver homogenates obtained with UDP-glucuronic acid, UDP-glucose and UDP-xylose were 1:1.5:2.7 for untreated preparations and 1:0.29:0.44 after activation with digitonin. 5. Bilirubin UDP-glucuronyltransferase was protected against denaturation by human serum albumin, whereas bilirubin UDP-xylosyltransferase was not. 6. Digitonin-treated and untreated liver homogenates from Gunn rats were inactive in transferring sugar to bilirubin from UDP-glucuronic acid (in agreement with the work of others), UDP-glucose or UDP-xylose.
TL;DR: Intramuscular injections of human growth hormone, although inducing marked increases in the immunoassayable growth hormone of serum, do not alter immediately SBβG activity and the decrease in plasma binding after an arginine infusion was paralleled in 4 out of 5 cases by an acute fall in serum testosterone.
TL;DR: In this paper, the problem of estimating the residual variance σ2 in the linear regression model is discussed, where the components of the random vector ∈ are stochastically independent but we do not assume that the k-xtosis of the distribution, β − 3, is equal to zero.
Abstract: In this paper we discuss the problem of estimating the residual variance σ2 in the linear regression model . We assume that the components of the random vector ∈ are stochastically independent but we do not suppose that the k-xtosis of the distribution, β – 3, is equal to zero. I t is investigated when a quadratic estimator of σ2 is best quadratic estimator or best quadratic unbiased estimator. Especially the question is of interest under which conditions a multiple of the projection-matrix leads to such estimator. In both cases the Hsu-condition necessary and sufficient. Imposing positive-definiteness on the estimator does not weaken this eondition. The obtained estimators are show-n to be positive-semi-definite if ∣β – 3∣ < 2.For the practical applicability the question is what is to do if β is unknown. For this purpose admissible quadratic estimators of σ2 are determined. The proofs of the theorems are based on a general projection theorem for quasi-inner prodncts which is given in section 2.
TL;DR: In this paper, a generalization of the perturbation method is applied to the problem of the radial and non-radial oscillations of a gaseous star which is distorted by a magnetic field.
Abstract: A generalization of the perturbation method is applied to the problem of the radial and the non-radial oscillations of a gaseous star which is distorted by a magnetic field. An expression is derived for the perturbation of the oscillation frequencies due to the presence of a weak magnetic field when the equilibrium configuration is a spheroid. The particular application to the homogeneous model with a purely poloidal field inside, due to a current distribution proportional to the distance from the axis of symmetry, and a dipole type field outside is considered in detail. The main result is that the magnetic field has a large and almost stabilizing effect on unstableg-modes, particularly on higher order modes. With the considered magnetic field the surface layers appear to have a large weight.
TL;DR: The experiments show that electrofocusing can profitably be used to study ligand-protein interactions and that radioligand detection is not always an adequate method to localize a macromolecular binding agent.
01 Sep 1972
TL;DR: In this article, an instantaneous viscoelastic response is used to describe the changes with time in thixotropic materials, which is evaluated experimentally using oscillatory measurements using a polyamide gel.
Abstract: Reversible time-dependent effects in thixotropic materials are considered. In order to describe the changes with time an instantaneous viscoelastic response is used which is evaluated experimentally using oscillatory measurements. The method is evaluated using a polyamide gel. Characterization by means of the storage modulus in the plateau zone is discussed and its practical feasibility is shown using the same gel. The experimental data can be used directly and formally to establish the kinetics of thixotropic changes in structure. With the system under consideration a rate equation of a linear relaxation type is found; it does not correspond to any simple order rate equation of the kind frequently used in studies of thixotropy.
TL;DR: Prolonged incubation, low concentrations of bilirubin and high concentrations of UDP-xylose favoured diconjugate formation, and analogous evidence established the structure of the reaction product obtained with UDP-glucose as the sugar donor, as bilirUBin beta-d-monoglucoside.
Abstract: 1. In incubation mixtures containing digitonin-activated or untreated preparations from rat liver, albumin-solubilized bilirubin as the acceptor substrate and (a) UDP-glucuronic acid, (b) UDP-glucose or (c) UDP-xylose as the sugar donor, formation of the following ester glycosides was demonstrated: with (a), bilirubin beta-d-monoglucuronoside, with (b), bilirubin beta-d-monoglucoside and with (c), bilirubin monoxyloside or mixtures of the mono-and di-xyloside. 2. With UDP-glucuronic acid prolonged incubation and variation of the composition of the incubation mixtures yielded equimolar amounts of azodipyrrole (I) and azodipyrrole beta-d-monoglucuronoside (II) after treatment of the incubation mixtures with the diazonium salt of ethyl anthranilate. The azo-derivatives were identified by t.l.c. by reference to known compounds and by the following chemical tests. After ammonolysis the conjugated azo-derivative (II) yielded d-glucuronic acid and the carboxylic acid amide of azodipyrrole, indicating transfer of a glucuronic acid residue to the carboxylic acid groups of bilirubin. The beta-d-configuration of the sugar moiety and binding at C-1 were demonstrated by enzymic hydrolysis tests. 3. Analogous evidence established the structure of the reaction product obtained with UDP-glucose as the sugar donor, as bilirubin beta-d-monoglucoside. 4. With UDP-xylose as the sugar donor xylosyl transfer to the carboxylic acid groups of bilirubin with attachment at C-1 was demonstrated in an analogous way. A beta-d-configuration is considered very likely, but requires confirmation. 5. Monoxyloside formation was predominant at pH7.4, whereas at decreasing pH values increasing fractions of the substrate were converted into the dixyloside. Prolonged incubation, low concentrations of bilirubin and high concentrations of UDP-xylose favoured diconjugate formation. The available evidence supports the synthesis sequence: bilirubin --> bilirubin monoxyloside --> bilirubin dixyloside.
TL;DR: In this article, the β-type copper-aluminium martensite has two phases characterized by a long period superlattice, the α 2 -phase, being an equilibrium phase, has an f.c. structure as basic structure.
TL;DR: It is important to correlate morphological and functional aspects of dysplasia and to establish diagnostic criteria for making the diagnosis of dyserythropoietic anaemia.
Abstract: When, for one or other reason, haemopoiesis is disturbed it may at times be difficult to know how to describe the phenomenon which has occurred, especially if the disturbance is both quantitative and qualitative. The random use of such terms as aplasia, hypoplasia, dyshaemopoiesis, dyserythropoiesis and dyserythropoietic anaemia may give rise to confusion. It would seem rational to use the terms aplasia and hypoplasia to describe conditions in which there is a quantitatively decreased haemopoiesis, so that the bone marrow produces and releases an insufficient number of blood cells into the circulation. Dysplasia, on the other hand, would describe the situation where there is a qualitative abnormality of the bone marrow. This may result in inefficient or ineffective haemopoiesis or, if limited to the erythroid cells (i.e. dyserythropoiesis), in ineffective erythropoiesis. It implies either a defect primarily of a stem cell with consequent abnormality of development of the cell line or lines, or an abnormal environmental state within the bone marrow which inhibits normal cell proliferation, or a combination of both factors. In practice hypoplasia alone is the exception rather than the rule and aplastic anaemia is usually accompanied by dysplasia. Dysplasia may occur in a wide range of diseases which primarily affect either the nucleus or the cytoplasm of the erythroblast. It is present in megaloblastic anaemias, thalassaemia and erythroleukaemia. A dyserythropoietic component of greater or lesser severity occurs in aplastic anaemia, myelosclerosis, iron deficiency and iron utilization defects, including acquired sideroblastic anaemias, and in infections (Lewis, 1969; Dreyfus et a!, 1969a). It also occurs as a congenital disorder (Crookston et al, 1969; Verwilghen et al, 1969), and (? rarely) as a primary acquired defect (Lewis, 1969, 1972). The term dyserythropoietic anaemia should be confined to these congenital and acquired primary cases in order to distinguish them from the dysplasia which is associated with identifiable diseases. Congenital sideroblastic anaemias might be included in this group. It is important to correlate morphological and functional aspects of dysplasia and to establish diagnostic criteria for making the diagnosis of dyserythropoietic anaemia.
TL;DR: In cellular ion exchange studies it is usually assumed that inhibition of metabolism does not affect the passive membrane characteristics, but the study of the ion distribution and the extracellular space of taenia coli cells revealed that the 14C-sorbitol and 14C -sucrose space of tissues, increased over control values during exposure to N2 agitated glucose-free solution.
Abstract: IN cellular ion exchange studies it is usually assumed that inhibition of metabolism does not affect the passive membrane characteristics and that the concomitant modifications of the ion exchange are largely caused by a deficient energy supply to the active ion transport systems. Our study of the ion distribution and the extracellular space of taenia coli cells revealed, however, that the 14C-sorbitol and 14C-sucrose space of tissues, increased over control values during exposure to N2 agitated glucose-free solution. We prevented this extra sorbitol uptake by addition of 10 mM La3+, which also decreases membrane permeability to cations1,2. Since La3+ was also able to partially reverse the increased membrane permeability caused by metabolic depletion we were able to trap 14C-sorbitol molecules and thus prove their penetration into the cells.
TL;DR: Noninvasive recording of the apex cardiogram, using a method that measures precordial impulse pressure variations, may provide useful information related to left ventricular function and is particularly valuable in the assessment ofleft ventricular diastolic pressure events.
Abstract: The effect of various alterations in preload, afterload and inotropic state of the left ventricle on the apex cardiogram was studied in 42 anesthetized dogs, in an attempt to clarify some of the determinants of the apical impulse. Conventional and calibrated apex cardiograms were recorded simultaneously with high-fidelity left ventricular and arterial pressure tracings, electrocardiogram and first time derivatives (dp/dt) of the apex cardiogram and left ventricular pressure. A definite relation between left ventricular pressure and the apex cardiogram could be demonstrated with regard to the diastolic as well as systolic components of both curves. Higher systolic deflections in the apex cardiogram were found for the same left ventricular systolic pressure whenever left ventricular end-diastolic volume or stroke volume was increased. A high correlation existed between diastolic waves of left ventricular pressure and calibrated precordial pulsation tracings. It was concluded that the amplitude of the systolic complex of the apex cardiogram depends on many factors, whereas the genesis of the diastolic components is probably much simpler. The results presented indicate that noninvasive recording of the apex cardiogram, using a method that measures precordial impulse pressure variations, may provide useful information related to left ventricular function and is particularly valuable in the assessment of left ventricular diastolic pressure events.
TL;DR: Clinical experience shows that a significant number of failures of intramedullary nailing for fractures is due to mechanical factors.
Abstract: Clinical experience shows that a significant number of failures of intramedullary nailing for fractures is due to mechanical factors.
01 Jan 1972
TL;DR: In this article, it was shown that le comportement spectral de UO2++, dans la region s'etendant entre 20 000 and 30 000 cm-1, est influence essentiellement par certaines proprietes de l'environnement immediat de luranyle.
Abstract: Les spectres d’absorption des complexes d’uranyle avec les ligandes bidentates NO3- , HCOO- , CH3 COO- , C2 O4 —, CO3 —, SO4 -- ont ete pris en solution et a l’etat solide.L’analogie entre les spectres correspondant a ces deux phases permet de conclure que le comportement spectral de UO2++ , dans la region s’etendant entre 20 000 et 30 000 cm-1, est influence essentiellement par certaines proprietes de l’environnement immediat de l’uranyle.Plus specifiquement on montre que la symetrie de la premiere sphere de coordination equatoriale de UO2 ++ determine l’intensite et le nombre de transitions electroniques dans le spectre. Par contre la nature chimique des ligandes en influence la structure vibrationnelle.