Showing papers by "Ghent University published in 1978"
TL;DR: Coronavirus-like particles were detected by electron microscopy in the intestinal contents of pigs during a diarrheal outbreak on 4 swine breeding farms, which was found to be distinct from the known porcine coronaviruses, transmissible gastroenteritis virus and hemagglutinating encephalomyelitis virus.
Abstract: Coronavirus-like particles were detected by electron microscopy in the intestinal contents of pigs during a diarrheal outbreak on 4 swine breeding farms. Diarrhea was reproduced in experimental pigs with one of the isolates, designated CV777, which was found to be distinct from the 2 known porcine coronaviruses, transmissible gastroenteritis virus and hemagglutinating encephalomyelitis virus.
710 citations
121 citations
TL;DR: Because of their easy hatching from dry cysts and their year-round availability, nauplii of the brine shrimp Artemia salina are most convenient test organisms for toxicity studies.
119 citations
TL;DR: The tamoxifen, 20 mg/day for 10 days, to normal males produced a moderate increase in luteinizing hormone (LH), follicle-stimulating hormone (FSH), testosterone, and estradiol levels, comparable to the effect of 150 mg of clomiphene citrate (Clomid) as discussed by the authors.
106 citations
TL;DR: The stability of HeLa cell poly (A)-free histone mRNAs injected into Xenopus oocytes is studied, and the effect of 3′-OH polyadenylation on this stability is studied.
Abstract: WE have shown that, when injected into Xenopus oocytes, poly (A) free globin messenger RNA is translated for a short period of time and then rapidly degraded1–3, while, under the same conditions, native mRNA shows a marked stability1,2,4 The poly (A) segment itself is responsible for the stability of native globin mRNA, since its readdition to previously de-adenylated mRNA restores the stability of the message5 We have shown also that the poly (A) stretch must contain a minimum number of adenylate residues to ensure its protective function6 It was interesting to see whether the concept of the stabilisation of eukaryotic mRNAs by 3′-OH polyadenylation is general This can be done by looking at the effect of the presence of a 3′-OH poly (A) segment on the stability of various mRNAs Here we study the stability of HeLa cell poly (A)-free histone mRNAs injected into Xenopus oocytes, and the effect of 3′-OH polyadenylation on this stability
82 citations
TL;DR: Stepwise discriminant analyses between tertile III and tertile I introducing psychological, social and bioclinical variables showed that the ‘obese’ subjects (tertile III) are less frequently cigarette smokers, are less neurotic, are of a lower occupational class, are more frequently living in Wallonia (south of Belgium) and are more extravert compared to the ’lean’Subjects.
78 citations
TL;DR: In vitro experiments indicated that cytoplasmic microtubules were involved in malignant invasion and that cell division and invasion constituted separate characteristics of malignant cells.
Abstract: The malignant C3H/3T3 mouse cells MO4 invaded embryonic chick heart fragments in an organotypic coculture system on semisolid medium, which mimicked malignant invasion. In this system, at a dose of 1 microgram/ml, the microtubule inhibitors colchicine, demecolcine, vincristine sulfate, vinblastine sulfate, or methyl[5-(2-thienylcarbonyl)-1H-benzimidazol-1-yl]-carbamate (Nocodazole) totally inhibited malignant invasion. At the same dose the drugs were also mitostatic, which was apparent from C-mitoses and from the absence of postmetaphase figures. At a mitostatic dose of 10 microgram/ml, 5-fluorouracil (FUra), cytosine arabinoside, or bleomycin did not interfere with malignant invasion. Combined treatment of the cocultures with the antimetabolite FUra (10 microgram/ml) plus the microtubule inhibitor Nocodazole (1 microgram/ml) completely inhibited invasion. These cocultures also showed the effective inhibition of mitosis by FUra, because Nocodazole-induced C-mitoses were absent. The reversibility of the anti-invasive effect of 4-day treatment with Nocodazole (1 microgram/ml) was demonstrated in shaker cocultures with the use of fluid medium. Our in vitro experiments indicated that cytoplasmic microtubules were involved in malignant invasion and that cell division and invasion constituted separate characteristics of malignant cells.
70 citations
58 citations
TL;DR: In a patient with hydramnios, fetal hydrops was diagnosed by B mode ultrasound by visualize fluid in the fetal pleural cavity and the diagnosis (congenital chylothorax) was confirmed at autopsy.
Abstract: In a patient with hydramnios, fetal hydrops was diagnosed by B mode ultrasound. Gray scale sonography visualized fluid in the fetal pleural cavity. The diagnosis (congenital chylothorax) was confirmed at autopsy.
49 citations
TL;DR: It has been confirmed that sunstruck flavour is due to the formation of 3-methyl-2-butene-1-thiol formed by photolysis of iso-α-acids in the presence of sulphur-containing amino acids as mentioned in this paper.
Abstract: It has been confirmed that sunstruck flavour is due to the formation of 3-methyl-2-butene-1-thiol formed by photolysis of iso-α-acids in the presence of sulphur-containing amino acids.
44 citations
TL;DR: In this article, a heterojunction solar cell is analyzed to find the optimum structure, in which one type of carriers are majority carriers at the interface and their concentration can be known a priori.
Abstract: A heterojunction solar cell, in which interface recombination and arbitrary energy barriers at the interface occur, is analysed to find the optimum structure. Thermionic emission theory is used; it is assumed that one type of carriers are majority carriers at the interface and that their concentration can be known a priori. It is shown that these assumptions do not seriously limit the applicability of the theory. The results are discussed in the case when one semiconductor is much more heavily doped than the other, which is a condition that certainly improves the efficiency of the solar cell.
TL;DR: The reproductive potential of O. oxyuris is much lower than would be predicted from body size; this and the dominance of males in the population, is discussed in the light of the evolution of stable predator-prey systems.
Abstract: The large nematode Oncho!aimus oxyuris Ditlevsen, 1911 is a dominant predator in a shallow polyhaline brackish-water pond in Belgium. The reproductive potential of this species was calculated as the intrinsic rate of natural increase r = I/D in PNe, in which D is the generation time, p is the percentage of females, and N e is the number of eggs per female. The generation time varies between 570 days at 5oc and 101 days at 25oc and is the main factor in the determination of r. The relationship between r and temperature is nearly linear and is given by r = 0.0013 T 0.0042. The reproductive potential of o. oxyuris is much lower than would be predicted from body size; this, and the dominance of males in the population, is discussed in the light of the evolution of stable predator-prey systems.
TL;DR: A GLC method for the simultaneous quantitative determination of the cis- and trans-isomers of doxepin and desmethyldoxepin in human plasma was developed, achieving high sensitivity with a nitrogen detector, enabling quantitation of the compounds in plasma of humans treated chronically with dozepin.
TL;DR: The low dose intravenous glucose tolerance test (IVGTT) and the insulin response to the glucose load were performed in a series of diabetic dogs and it is suggested that these types represent stages in the natural history of the development of diabetes mellitus in dogs.
Abstract: The low dose intravenous glucose tolerance test (IVGTT) and the insulin response to the glucose load were performed in a series of twenty–two diabetic dogs. All diabetic dogs were characterized by glucose intolerance as expressed by an abnormal half time (Tl/2) or fractional turnover rate (k) for glucose clearance. On the basis of the initial insulin level (Io), the insulin peak response (Ip) and the insulinogenic index (I/G), the dogs were classified into three types. Type I dogs were characterized by a low Io, low Ip and low I/G in response to glucose, similar to the juvenile form of diabetes in humans. Type II dogs were characterized by a normal or high Io, but also with a low Ip and a low I/G which are some of the features of the maturity onset form. Type III dogs were characterized by a normal Io and a normal or delayed response to glucose as seen in chemical diabetes. It is suggested that these types represent stages in the natural history of the development of diabetes mellitus in dogs.
TL;DR: In view of a future standardization of protozoan toxicity tests a selection has been made on the basis of the applicability of the tests for routine analysis of ciliates as representative test organisms of the microfauna of aquatic ecosystems.
TL;DR: In this article, a comparative study of the 77 K PL spectra of about one hundred n-type GaAs single crys-tals, grown by the horizontal or Czochralski technique, shows that the principal native defects in the former (in the “as-grown” state) are As-vacancies, whereas Ga-vacs are dominating the latter (2).
Abstract: A comparative study of the 77 K PL spectra of about one hundred n-type GaAs single crys-tals, grown by the horizontal or Czochralski technique, shows that the principal native defects in the former (in the “as-grown” state) are As-vacancies, whereas Ga-vacancies are dominating the latter (2). Besides the VGa, copper appears as the major acceptor contaminant in these crystals and is respon-sible for the 0.83 eV peak. Association of Cu and/or VGa with VAs and/or dopant atoms tends to neutralise this compensation. Considering the contradicting attributions found in the literature, new definitions of the nature of some centers responsible for the deep-level PL were needed to fit with the experimental da-ta. Thus the center yielding the 1.35 eV, PL-band, usually identified as substitutional copper, has to be defined here as the As-va-cancy associated defect complex: (VAs+Cu=VAs+) Similarly the 1.295 eV PL is associated with the (Te+Cu=VAs+ complex and the often en-countered level at 1.22 eV is identified as the (Si+Cu=VAs +) complex. These levels, to-gether with the better known ones at 0.83, 0.96, 1.02, 1.17, 1.19 eV are linked in a coherent model which can account for the ap-pearance and the relative amplitude of the different PL peaks observed, as a result of the doping and the thermal history of the crystals during growth.
TL;DR: This brief paper deals with the return difference function and the inverse optimal control problem for linear single-input discrete-time systems with a quadratic performance criterion and its effect on the stability margins and the sensitivity properties of optimal feedback discrete- time systems is analysed.
TL;DR: In this paper, the complex residue ring C(m) modulo m is defined, and a necessary and sufficient condition is derived for N to be a possible transform length for a given number theoretic Fourier transform.
Abstract: The complex residue ring C(m) modulo m is first defined. Because of the existence of a ring isomorphism known as the Chinese remainder theorem (CRT), the study of C(m) can be limited to the cases where m = pe, p being a prime. C(pe) contains a multiplicative group, the group Q(pe) of the invertible elements. Q(pe) is shown to be the product of a group of order p2e-2and of a group R(pe), which is of order (p - 1)2when 4 divides (p - 1), and of order (p2- 1) when 4 is no divisor of (p - 1). It is shown that there exists an isomorphic mapping of Q(p) \longleftrightarrow R(p^{e}) . Consequently, the study of the orders of the elements of R(pe) can be reduced to studying those of Q(p). When 4 is not a divisor of (p - 1), Q(p) and R(pe) are cyclic groups of order (p2- 1). When 4 divides (p - 1), the elements of C(p) can be isomorphically mapped on Z(p) × Z(p), Z(p) being the set of real residue classes, mod p. In this case, the order of the elements of Q(p) and of R(pe) are limited to the divisors of (p - 1). When 4 does not divide (p - 1), all elements of R(pe) satisfy a set of orthogonality relations. This property also holds true for some of the elements of R(pe) when 4 divides (p - 1). The foregoing results are applied to number theoretic Fourier transforms in C(m). A necessary and sufficient condition is derived for N to be a possible transform length. It is shown that all reductions mod p\min{i}\max{e_{i}} of the transform factor where p\min{i}\max{e_{i}} represent the prime power factors of m, must belong to R(p\min{i}\max{e_{i}} and be of order N. Where Fermat number transforms (FNT) do not lead to transform lengths that are larger in C(m) than in Z(m), Mersenne number transforms result in a very large increase of the allowable values of N. The paper ends with a discussion on how a search procedure in Q(p) or in Z(p) allows to determine all available transform factors in Q(pe) for a given N.
TL;DR: The syntheses of willardiine and isowillardiine were studied in vivo in pea seedlings and in vitro with enzyme extracts from Pisum, Lathyrus, Albizia, Leucaena and Fagus seedlings by using uracil and O-acetyl- l -serine as substrates.
TL;DR: In this article, the advantages and disadvantages of growing whiskers on the inner wall of glass capillary columns are discussed, and several examples are presented to illustrate the possibilities of whisker-wall coated open tubular (WWCOT) columns.
Abstract: Growing whiskers on the inner wall of glass capillary columns is an easy roughening technique which allows efficient coating of the columns with any stationary phase. The advantages and disadvantages of whisker surfaces are discussed. Several examples are presented to illustrate the possibilities of whisker-wall coated open tubular (WWCOT) columns.
TL;DR: A detailed experimental and theoretical study of narrow ridge waveguides in glass films formed by ion-etching of patterns in photoresist has been carried out and a numerical approach, the finite-element method, has been used to compute theoretical dispersion curves.
Abstract: A detailed experimental and theoretical study of narrow ridge waveguides in glass films formed by ion-etching of patterns in photoresist has been carried out. Because the resultant waveguide profiles are trapezoidal a numerical approach, the finite-element method, has been used to compute theoretical dispersion curves. Experimental dispersion curves were obtained from measurements of output m-lines. Agreement between experiment and theory varies from moderately good to excellent over the range of waveguide profiles studied.
TL;DR: In this article, a new sealing procedure for the static coating technique in (GC)2 is described, which is quick and easy to carry out and can be used in a variety of applications.
Abstract: A new sealing procedure for the static coating technique in (GC)2 is described. The procedure is quick and easy to carry out.
TL;DR: In this paper, high resolution 57Fe Mossbauer effect measurements at room temperature were used to show that the spectra of pure, synthetic β-FeOOH in its paramagnetic state consist of a superposition of two discrete doublets, due to the existence of two different electric field gradients.
TL;DR: A single-column separation to the baseline of the protein amino acids as their N(O)-heptafluorobutyryl n-butyl ester derivatives in less than 35 min was obtained on the SE-30 column.
TL;DR: In this article, after transformation of amino acids to dimethylaminoazobenzenesulfonyl-(dabsyl) derivatives, these compounds are separated by HPLC on C18-reversed phase silica gel.
Abstract: After transformation of amino acids to dimethylaminoazobenzenesulfonyl-(dabsyl) derivatives, these compounds are separated (in the nanomole range) by HPLC on C18-reversed phase silica gel. Separation factors (temperature, pH, buffer composition, ionic strength) are studied.
TL;DR: In this article, a fast and accurate estimation technique for the heat transfer parameters of the two-dimensional pseudo-homogeneous reactor model is presented, where previous difficulties in the parameter estimation can be avoided by a more logical choice of these parameters.
TL;DR: The solution conformation of the ionophore Monensin in its free-acid form bears a close resemblance to that of its Na + salt as mentioned in this paper, and the pseudocyclic structure is shut by head-to-tail H bonding between the carboxylic function and the alcoholic functions of the last six-membered ring with mediation of a water molecule.