Showing papers by "Katholieke Universiteit Leuven published in 1973"
TL;DR: The entropy density of spin lattice systems is known to be a weak upper semi-continuous functional on the set of the lattice invariant states, and it is even weak discontinuous as mentioned in this paper.
Abstract: The entropy density of spin lattice systems is known to be a weak upper semi-continuous functional on the set of the lattice invariant states. (It is even weak discontinuous.) However we prove here that it is continuous with respect to the norm topology on those states.
468 citations
TL;DR: A twenty-year follow-up on the use of the Dunlap-Shands method for the determination of torsion of the femur is presented, with the results of a total of 1,990 torsions studies in normal children and children with congenital dislocation of the hip, coxa plana, toeing-in, and cerebral palsy.
Abstract: A twenty-year follow-up on the use of the Dunlap-Shands method for the determination of torsion of the femur is presented, with the results of a total of 1,990 torsion studies in normal children and children with congenital dislocation of the hip, coxa plana, toeing-in, and cerebral palsy. The effect of increased anteversion is discussed as it relates to each hip condition discussed. Increased anteversion should be considered a very significant factor in the treatment of many hip conditions.
367 citations
TL;DR: In this article, the general transport equations in a heavy doped semiconductor are given, taking the position-dependent band structure into account, and an intrinsic concentration depending on the doping levels is introduced.
Abstract: The general transport equations in a heavy doped semiconductor are given, taking the position-dependent band structure into account. An intrinsic concentration depending on the doping levels is introduced. This quantity allows us to use the classical equations in a slightly modified form, if Maxwell-Boltzmann statistics can be applied for one or both kinds of the carrier. The total density of states in a heavy doped semiconductor is assumed to be the envelope of the density of states of the conduction (valence) band and impurity band. The effect of the skewness of the impurity band is included. The Fermi level and the effective intrinsic carrier concentration are calculated for this total density of states function. Experimental evidence for the calculated values is given.
263 citations
TL;DR: It is proposed that the NEB's provide an intrapulmonary, hypoxia-sensitive neuro(chemo-) receptor system in addition to the well established central and peripheral (e.g. carotid body) chemoreceptors.
Abstract: In an attempt to further our knowledge about the structure and function of the recently identified intrapulmonary Neuro-epithelial Bodies (NEB's) (Lauweryns et al., 1972a, 1972b), lungs of 84 neonatal rabbits and 6 neonatal mice were studied along four different lines of investigation. Several routine and silver staining methods, Falck's fluorescent amine technic and histochemical and electron microscopical techniques were performed.
229 citations
TL;DR: Eubacterium 21,408, a strictly anaerobic bacterium, was isolated from rat cecal contents by its requirements for a Δ5-3β-hydroxy steroid and reduced the 5,6-double bond of cholesterol, campesterol, β-sitosterol and stigmasterol, exclusively yielding the corresponding 5β-saturated derivatives.
Abstract: Biohydrogenation of Δ5-steroids was studied in vitro by incubating various steroids with a pure culture of Eubacterium 21,408 in a brain-thioglycollate medium under anaerobic conditions.
1
Eubacterium 21,408, a strictly anaerobic bacterium, was isolated from rat cecal contents. It differed from any previously described Eubacterium species by its requirements for a Δ5-3β-hydroxy steroid.
2
Eubacterium 21,408 reduced the 5,6-double bond of cholesterol, campesterol, β-sitosterol and stigmasterol, exclusively yielding the corresponding 5β-saturated derivatives. Similarly, the 4,5-double bond of allocholesterol was reduced to yield coprostanol. Neither the 7,8-double bond in 7-dehydrocholesterol or in lathosterol, nor the 22,23-double bond in the side chain of stigmasterol were reduced.
3
In the absence of a 3-hydroxyl function (e.g. in cholest-5-ene), when the 3-hydroxyl function was in the 3α-position (e.g. in epicholesterol) or was substituted (e.g. in 3β-chloro-cholest-5-ene and in cholesteryl esters), no saturation of the 5,6-double bond was observed.
4
When incubated with Eubacterium 21,408, the carbonyl group of 4-cholesten-3-one, was reduced to the corresponding 3β-hydroxyl group along with saturation of the 4,5-double bond. The bacterium also reduced the 3-oxo group of cholestanone and coprostanone to a 3β-hydroxyl group.
192 citations
TL;DR: The intrapulmonary lining epithelium of rabbits contains newly identified corpuscles composed of argyrophil, argentaffin, yellow fluorescent, ultrastructurally granulated and innervated epithelial cellular organs which are proved, by electron microscopic cytochemistry and microspectrography, to be a source for intrapurmonary production of serotonin.
Abstract: The intrapulmonary lining epithelium of rabbits contains newly identified corpuscles composed of argyrophil, argentaffin, yellow fluorescent, ultrastructurally granulated and innervated epithelial cellular organs. These are proved, by electron microscopic cytochemistry and microspectrography, to be a source for intrapulmonary production of serotonin. Probably they are intrapulmonary neuroreceptor organs modulated by the central nervous system which exhibit local secretory activities.
138 citations
TL;DR: In this paper, the Weyl operators are obtained as a quotient of a universal C*-algebra by some of its ideals, and characterized all these ideals are shown to be degenerate when the symplectic form which defines the C.R. is possibly degenerate.
Abstract: We consider theC*-algebras which contain the Weyl operators when the symplectic form which defines the C.C.R. is possibly degenerate. We prove that the C.C.R. are all obtained as a quotient of a universalC*-algebra by some of its ideals, and we characterize all these ideals.
134 citations
01 Jan 1973
TL;DR: In this article, the concentrations of all stable and unstable species have been measured in the reaction zone of lean and stoichiometric methane-oxygen flames burning at 40 torr, and it is shown conclusively that the great majority of the methyl radicals is removed by Reaction [2], CH3+O→CH2O+H, with k2=1.3×1014 exp (−2000/RT).
Abstract: The concentrations of all stable and unstable species have been measured in the reaction zone of lean and stoichiometric methane-oxygen flames burning at 40 torr. The rate constant of Reaction [1], CH4+OH→CH3+H2O, was found to be k1=3×1013×exp(−6000/RT) mole−1 cm3 sec−1. In stoichiometric flames, half of the fuel is consumed via Reaction [1′], CH4+H→CH3+H2 and at T=1600°K, k1′ is reported to be 3.2×1012. It is shown conclusively that the great majority of the methyl radicals is removed by Reaction [2], CH3+O→CH2O+H, with k2=1.3×1014 exp (−2000/RT). The rate-determining step is a reaction resulting in an increase of the number of particles, Reaction [13]: CH2O+M→CO+H2+M; the value k13=2.1×1016 exp(−35,000/RT) was derived. Another part of the formaldehyde disappears via Reaction [3]: CH2O+OH→CHO+H2O; the rate constant is k3≅2.3×1013 in the range T=1400°–1800°K. Most of the CHO radicals react with O2: CHO+O2→HO2+CO; k4≅3×1013 at T=1600°K. In lean flames, HO2 is removed mainly by reactions involving OH and O: HO2+OH(O)→O2+H2O(OH); and k5≅5×1013 at T=1600°K. Carbon dioxide is formed by Reaction [6]: CO+OH→CO2+H; the rate constant was found to be k6=2.8×1011 at T=1750°K, and the activation energy E6=5.5±2 kcal/mole in the range T=1500°–1900°K. In the burned gas of lean flames, the radical “pool” decays by Reaction [11]: H+O2+M→HO2+M,the rate constant (for M=O2) being k11=2.5×1015 at T=1900°K.
120 citations
TL;DR: In this article, it was shown that the dimensionality of space-time serves as a cut-off for ultraviolet and infrared divergences, thus completely avoiding the introduction of a fictitious photon mass.
117 citations
TL;DR: In this article, the emitter efficiency of a bipolar transistor is calculated taking heavy doping effects such as impurity band formation and band tailing into account, and it is shown that in most cases these effects, rather than the minority carrier lifetime, are limiting the transistor current gain.
Abstract: The emitter efficiency of a bipolar transistor is calculated taking heavy doping effects such as impurity band formation and band tailing into account. It is shown that in most cases these effects, rather than the minority carrier lifetime in the emitter are limiting the transistor current gain. This allows us to define an effective emitter impurity profile for use in current transport calculations. The influence of the emitter and base impurity profiles upon the gain is studied, and experimental results are presented showing that the knowledge of the impurity profiles is sufficient to predict the one-dimensional current gain.
86 citations
TL;DR: In this article, the modified moments are used for the numerical calculation of integrals of functions having branch points, the computation of Chebyshev series coefficients and the construction of Gaussian quadrature formulas for integrals with logarithmic singularity.
Abstract: Recurrence formulas for the calculation of the modified moments
$$\int\limits_{ - 1}^{ + 1} {(1 - x)^\alpha (1 + x)^\beta T_n (x)dx} $$
and
$$\int\limits_{ - 1}^{ + 1} {(1 - x)^\alpha (1 + x)^\beta \ln \left( {\frac{{1 + x}}{2}} \right)T_n (x)dx} $$
are presented. Some applications of these modified moments are discussed, such as the numerical calculation of integrals of functions having branch points, the computation of Chebyshev series coefficients and the construction of Gaussian quadrature formulas for integrals with logarithmic singularity.
01 Dec 1973
TL;DR: In this paper, the phenomenological martensite theory is applied to the β 1 to β 1 martensitic transformation in Cu-Al and the resulting microstructure is verified with X-ray pole figures, which are combined with a single surface trace analysis based on the use of polarized light.
Abstract: The phenomenological martensite theory is applied to the β1 to β1 martensitic transformation in Cu-Al. Crystallographic and morphological aspects of the resulting martensitic microstructure are discussed and verified with X-ray pole figures, which are combined with a single surface trace analysis based on the use of polarized light. From the analysis of the orientation of any single martensite plate related to that of one or more neighboring plates, it can be proved that the martensite microstructure in each former β-grain is composed of at most six self-accommodating martensite plate groups, each of which consists of four different martensite plate variants.
01 Jan 1973
TL;DR: In this article, a study was made of pseudoelasticity and the strain-memory effect in βAg-Cd alloys having a low temperature martensitic transformation.
Abstract: A study has been made of pseudoelasticity and the strain-memory effect in βAg-Cd alloys having a low temperature martensitic transformation. Tests on single crystals showed that maximum pseudoelasticity occurred in specimens with the tensile axis oriented close to 〈001〉β at temperatures 20° to 50°C aboveM s. The habit plane for stress-induced martensite (SIM) was found experimentally to be ~(155)β and agreed well with a value obtained from the phenomenological theory assuming a (110) [110 ]β lattice-invariant shear. It is suggested that the macroscopic shear accompanying the transformation gives rise to the pseudoelastic strains, agreement with the experimental strain values being satisfactory. The strain-memory effect was explained as being due to a change from the (011) [011 ]β lattice-invariant shear associated with thermal martensite to the (110) [110]β shear associated with SIM.
TL;DR: In this article, the Nicollian-Goetzberger conductance method was used to analyze SiO2-interfaces with low oxide charge Qox and with a low surface states density Nss.
Abstract: By a careful process SiSiO2-interfaces can be made with a low oxide charge Qox and with a low surface states density Nss. For dry oxides on (100) Nss-values as low as a few 109 cm−2 eV−1 are found on samples with an oxide charge density of 3·0 × 1010 cm−2. Only the Nicollian-Goetzberger conductance method is proved to give reasonable results on these structures. The quasi-static low frequency C-V-technique is in good agreement with the conductance technique for samples with Nss-values higher than 1·0 × 1010 cm−2 eV−1. The spatial fluctuation of surface potential, mainly caused by oxide charge fluctuations, is an important parameter when studying the high or low frequency C-V-characteristics. Some irregularities in the experimental Nss-φs-curves are explained.
TL;DR: Nous supposons que parmi leurs diverses fonctions neuroréceptrices possibles, ces «Corpuscules Neuro-épithéliaux» forment un système intrapulmonaire chémorécepteur sensible à l'hypoxie, en plus des ché MORécepteurs centraux et périphériques.
Abstract: Les «Corpuscules Neuro-epitheliaux» de l'epithelium respiratoire intrapulmonaire ont ont ete etudies au microscope optique et electronique chez des lapins soumis a des conditions experimentales d'hypoxie. Dans ce cas ils secretent a leur pole vasculaire basal leurs vesicules a noyau dense contenant de la serotonine. Nous supposons que parmi leurs diverses fonctions neuroreceptrices possibles, ces «Corpuscules Neuro-epitheliaux» forment un systeme intrapulmonaire chemorecepteur sensible a l'hypoxie, en plus des chemorecepteurs centraux et peripheriques (par exemple le corps carotidien) dont l'existence est bien connue. Ils secretent de la serotonine et probablement aussi des substances aminees ou peptidiques associees qui influenceraient la vasoconstriction pulmonaire et sont modules par le systeme nerveux central.
TL;DR: This work wondered whether a similar mechanism would initiate platelet aggregation by bovine factor VIII, and identified a substrate-enzyme complex formed between side chains of collagen containing galactose but not terminated by sialic acid and sialyl transferase located on the platelet membrane.
Abstract: RECENT work1,2 has demonstrated that bovine factor VIII, not bovine fibrinogen, aggregates human platelets This aggregation can occur in two waves, the first being independent of release of platelet adenosine-5′-diphosphate Bovine factor VIII is rich in carbohydrate: it contains 11% hexoses (mannose and galactose, in a ratio of 1 to 3), 2% sialic acid and 7% hexosamine3 Carbohydrate side chains would play a critical role in collagen–platelet adhesion and subsequent aggregation; a substrate-enzyme complex4 would be formed between side chains of collagen containing galactose5 but not terminated by sialic acid and sialyl transferase located on the platelet membrane6 Oxidation of the galactosyl residues in collagen abolishes platelet aggregation5 We wondered whether a similar mechanism would initiate platelet aggregation by bovine factor VIII
TL;DR: Human platelet-rich plasma clotted by reptilase does not retract, and a scheme linking the platelet adhesion-aggregation reaction and clot retraction and indicating the level of inhibition of several compounds is proposed.
TL;DR: Levamisole, a broad-spectrum anthelmintic, increased the delayed hypersensitivity skin reaction to tuberculin and to DNCB in about one third of the patients.
TL;DR: The results are interpreted as indicating that non‐infectious A‐type particles are synthetized by a mechanism different from that by which infectious C‐ type particles are generated.
Abstract: Three types of oncornavirus-carrying mouse cell lines were studied. Replication of endogenous sarcoma or leukemia viruses in cell lines producing the infectious viruses was as sensitive to inter feron as that of exogenous vesicular stomatitis virus (VSV). Replication of non-infectious C-type virus in S+L− cells which carry a rescuable Moloney sarcoma virus (MSV) genome did not respond to interferon. However, this cell line was also found to be 70 times less responsive to interferon when tested by an exogenous VSV challenge. Finally, after exposure to interferon, M04 cells, which carry a rescuable MSV genome and produce non-infectious A-type particles, developed normal resistance to VSV. Yet, high doses of interferon could not prevent the induction of surplus A-type particles by bromodeoxyuridine (BDU) and dimethylsulfoxide (DMSO). The results are interpreted as indicating that non-infectious A-type particles are synthetized by a mechanism different from that by which infectious C-type particles are generated.
TL;DR: In this paper, the differential cross section for e + e − → γγ is calculated to order α 3 for the case of e+ e − colliding beam experiments. But the authors do not consider the effect of hard photon corrections in the forward direction.
TL;DR: Cell lines derived from C3H mouse embryos are described and Untransformed MO-cells were found susceptible to transformation by Kirsten MSV, and two types of transformed cell lines were isolated.
Abstract: Cell lines derived from C3H mouse embryos are described. Untransformed MO-cells were found susceptible to transformation by Kirsten MSV. Two types of transformed cell lines were isolated. MO-P-cells produced infectious MSV and contained extracellular C-type particles. MO4-cells did not release infectious focus forming virus; however, upon superinfection with murine leukemia viruses (MLV), infectious MSV was released. Not superinfected MO4-cells contained multiple intracisternal A-type particles. In this respect these cells differ from the MSV genome-carrying NP-cells (1) which do not produce particles nor viral antigen, and from S+L−-cells (2) which release extracellular, non-infectious C-type particles.
TL;DR: In this article, the α 3 -contribution to the angular asymmetry in the differential cross section for e + e − → μ + μ − is calculated, including hard photon emission.
TL;DR: The most important characteristics of the MOS transistor operating in weak inversion are discussed in this paper, where it is shown that the drain current can be written as the product of the geometrical factor W/L, the minority carrier diffusion constant, and the inversion charge at the source.
Abstract: The most important characteristics of the MOS transistor operating in weak inversion are discussed. When the drain voltage is greater than a few kT/q it is demonstrated that the drain current can be written as the product of the geometrical factor W/L , the minority carrier diffusion constant, and the inversion charge at the source. In the classical theory, the slope of the In I D versus V G curve is only influenced by the capture of minority carriers by surface states. It is demonstrated that the N ss values obtained from these current measurements are in disagreement with the values found by independent surface states measuring techniques.
TL;DR: The results indicate that the presence of an intact thymus is not needed for the production of IgM, but seems to play an important part in theproduction of IgA and IgG.
Abstract: The immunoglobulin levels of the various mouse immunoglobulin classes in sera of genetically thymusless (nu/nu) mice and their littermate controls with thymus (nu/+) were determined. The amounts of IgM in nu/nu and control mice were equal, but the amounts of IgA, IgG1, IgG2a and IgG2b in nu/nu mice of 10 weeks were, respectively, 14, 3, 27 and 14 % of those in control mice. Our results indicate that the presence of an intact thymus is not needed for the production of IgM, but seems to play an important part in the production of IgA and IgG.
TL;DR: The sterol fractions of different morphological and physiological parts of etiolated Mung bean seedlings have been studied in this paper, showing that the sterol fraction of young growing tissues conta
TL;DR: NH2- terminal lysine or valine plasminogen can be derived from NH2-terminal glutamic acid pl asminogen by plAsmin digestion.
TL;DR: Female R rats mated with an R male and inoculated in utero, after fetectomy, with murine sarcoma virus (Moloney), developed tumors that originated in the uterus and were of fetal origin.
Abstract: Female R rats mated with an R male and inoculated in utero, after fetectomy, with murine sarcoma virus (Moloney), developed tumors. These tumors originated in the uterus and were of fetal origin. Intravenous or intraperitoneal injection of the virus induced similar tumors. Infectious virus could not be isolated from the tumor cells kept as transplantable lines or cultured in vitro. However, the presence of the MSV genome could be demonstrated by a direct rescue test. In non-pregnant rats treated in the same way no neoplasms were recorded. The results are discussed in the light of current theories on the special immunological fetal-maternal relationship.
TL;DR: A malformed newborn with a previously unreported partial trisomy 1 due to an unbalancierten familiären Translokation is given.
Abstract: Description is given of a malformed newborn with a previously unreported partial trisomy 1 due to an unbalanced familial translocation (karyotype 46,XY,12-,t(1q, 12p)+).
TL;DR: In this paper, the authors examined the necessity of a bolus for the progression of the primary esophageal peristaltic contraction and found that a primary peristALTic contraction is entirely bolus-dependent only in its course through the cervical esophagus but not through the thoracic part of the gullet.