Fructose 2,6-bisphosphate and glycolytic flux in skeletal muscle of swimming frog

1990

AbstractGlycolytic flux in skeletal muscle is controlled by 6-phosphofructokinase but how this is achieved is controversial. Brief exercise (swimming) in frogs caused a dramatic increase in the phosphofructokinase activator, fructose 2,6-bisphosphate, in working muscle. The kinetics of phosphofructokinase suggest that in resting muscle, the enzyme is inhibited by ATP plus citrate and that the increase in fructose 2,6-bisphosphate is part of the mechanism to activate phosphofructokinase when exercise begins. When exercise was sustained, fructose 2,6-bisphosphate in muscle was decreased as was the rate of lactate accumulation. Glycolytic flux and the content of fructose 2,6-bisphosphate appea…

IL SENO UROGENITALE COMUNE: considerazioni etiopatogenetiche, c liniche e terapeutiche

1990

Gli Autori riportano la loro casistica e considerano gli aspetti embriogenetici, endocrinologici, clinic del Seno Urogenitale Comune e sintetizzano i possibili approcci terapeutici

Dielectric study of orientational disorder in (CO2)1−x(N2O)xmixed crystals

1990

The dipolar relaxation dynamics of solid solutions of carbon dioxide and nitrous oxide has been investigated using dielectric spectroscopy. The temperature dependence of the relaxation rate reveals an ideal Arrhenius behavior for all concentrations, with energy barriers which scale linearly between the two pure compounds. The attempt frequencies are anomalously high. The distribution of relaxation times due to the static random fields as introduced by the substitutional impurity molecules is almost negligible. The melting temperature is determined by a critical relaxation rate of 40 kHz.

Majorons and supernova cooling

1990

We consider the role of Majoron emission in supernova cooling and its implications for the neutrino mass and lifetime in generic single Majoron models. It is found that, for ${\ensuremath{\nu}}_{\ensuremath{\tau}}$ with mass $m$, if the lifetime for the decay ${\ensuremath{\nu}}_{\ensuremath{\tau}}\ensuremath{\rightarrow}\mathrm{Majoron}+{\ensuremath{\nu}}_{e,\ensuremath{\mu}}$ is shorter than ${10}^{\ensuremath{-}7}$ (m/MeV) sec, then Majorons are so strongly trapped by the inverse process that the resulting Majoron luminosity is small enough not to destabilize the observed ${\ensuremath{\nu}}_{e}$ pulse from SN 1987A. For ${\ensuremath{\nu}}_{\ensuremath{\tau}}$ with a longer lifetime, th…

Aminosäureester als chirale Hilfsgruppen in Lewis-Säure-katalysierten Diels-Alder-Reaktionen

1990

Amino Acid Esters as Chiral Auxiliaries in Lewis Acid Catalyzed Diels-Alder Reactions Cyclopentadiene, cyclohexadiene and alkyl-substituted butadienes react with N-acryloyl-, N-crotonoyl- and N-(4-nitro-cinnamoyl)-(S)-proline benzyl and allyl ester in the presence of Lewis acids to give the cycloadducts in high yields and with stereoselectivities of up to 97:3 for the endo isomers. The sense of the asymmetric induction in these reactions can be directed by the use of differently coordinating catalysts (e.g. TiCl4: (2R):(2S) = 96:4; EtAlCl2: (2R):(2S) = 10:90 at 0°C). In the TiCl4-catalyzed reactions with the fumaric acid derivatives the ratio of the diastereomers reaches values of up to 112…

Thermische Diels-Alder-Reaktionen mitN-(2-Alkenoyl)-(S)-prolinestern als chiralen Dienophilen in organischen und wäßrigen Reaktionsmedien

1990

Thermal Diels-Alder Reactions with N-(2-Alkenoyl)-(S)-proline Esters as Chiral Dienophiles Cyclopentadiene reacts with N-acryloyl-(S)-proline benzyl and allyl ester in toluene at 0°C to give the bicycloheptene-carboxylic acid amides with a stereoselection of (2S):(2R) = 81:19. In the reactions with the N,N′-fumaroylbis(proline esters) the cycloadducts are formed in high yields and with isomer ratios of up to 97:3. The absolute configuration of N,N′-〈(1R,2R,3R,4S)-bicyclo[2.2.1]hept-5-ene-2,3-diyldicarbonyl〉bis-[(S)-proline benzyl ester] (6 a) has been determined by an X-ray analysis. In the reactions of the acrylamides with cyclopentadiene and of the fumaramides with cyclopentadiene, isopre…

Glomerular basement membrane: evidence for collagenous domain of the alpha 3 and alpha 4 chains of collagen IV.

1990

Abstract A collagenous component(s) of Mr = 60K was extracted from glomerular basement membrane with urea and was purified. Upon digestion, it yielded a collagenase-resistant fragment(s) of Mr = 23.5K. Both component and fragment showed immunochemical identity with the noncollagenous domains of the new α3 & α4 chains of collagen IV. The component is characterized by a collagenous domain of about 280 residues and a noncollagenous domain of about 250 residues. These findings further establish these new chains as distinct entities of collagen IV.

The arid–humid transition in the Sahara and the Sahel during the last deglaciation

1990

At the time of the Last Glacial Maximum, the Sahara and Sahel regions of North Africa were extremely dry. New records of rainfall show that during the subsequent deglaciation, the transition from arid to humid conditions in these regions occurred synchronously in two main steps. Comparison with other records of palaeoclimate in Europe and the North Atlantic Ocean shows that certain common factors controlled changes in ocean and atmosphere dynamics during the deglaciation.

Effect of claustrum stimulation on neurons of the contralateral medial oculomotor area, in the cat

1990

In chloralose-anaesthetized cats, the extracellular spontaneous unitary activity was recorded from 157 neurons, located in the medial oculomotor area. 98 units were identified as projecting onto the superior colliculus. Electrical stimulations of the contralateral claustrum provoked, on 13 of these cells, an excitatory effect, lasting 10-35 ms and appearing with a latency of 20-50 ms. Full length section of the corpus callosum totally abolished the contralateral claustrum effect. The results suggest that in the cat, the claustrum may have a role in the bilateral control of the visuo-motor performance.

Steatocrit test: Normal range and physiological variations in infants

1990

In order to define the normal values of steatocrit during the first 3 months of life and the normal correlation between fecal fat content and steatocrit values, 60 full-term healthy unweaned infants (30 bottle-fed, 15 breast-fed, and 15 mixed-fed) were studied. The steatocrit micromethod was performed in these babies at 7, 14, 21, 28, 45, and 90 days after birth. Steatorrhea often occurs during the first month and then decreases, as shown by the fall in the steatocrit curve from 7th to 28th day in our subjects; at 45 days, few babies have steatorrhea. The 90th percentile profile of steatocrit values shows a value of 25% at the first week of life and a value of 13% at the fourth week. After …

Two groups with isomorphic group algebras

1990

Nuclear charge radii of the tin isotopes from muonic atoms.

1990

The muonic atom 2${\mathit{p}}_{1/2}$-1${\mathit{s}}_{1/2}$ and 2${\mathit{p}}_{3/2}$-1${\mathit{s}}_{1/2}$ transition energies were measured with an experimental accuracy of better than 20 ppm for the isotope chain $^{112,114,116,117,118,119,120,122,124}\mathrm{Sn}$. Precise values for the Barrett equivalent nuclear radii ${\mathit{R}}_{\mathit{k}\mathrm{\ensuremath{\alpha}}}$ and their differences as well as root-mean-square radii were deduced. The \ensuremath{\Delta}N=2 isotope shifts between the even Sn isotopes show a subshell effect at the neutron number N=64. Otherwise, there is a nearly linear decrease with increasing N, in accordance with the general systematics of nuclear charge r…

On embedding Boolean as a subtype of integer

1990

The enveloping algebra of the Lie superalgebra osp(1,2)

1990

International audience

Image synthesis using the Lau effect

1990

Abstract Based on the Lau effect at finite distances, we describe a lensless optical setup for synthesizing laterally periodic images; which are composed of several, incoherently superimposed, object substructures. Some experimental verifications are also reported.

Autoantibodies to cytochrome P450s in idiopathic autoimmune type chronic active hepatitis

1990

The passivation of steel in sodium sulphate solution studied by CEMS and aes

1990

The passive layer formed on standard steel by anodic oxidation in 0.5 M sodium sulphate solution was found to contain iron only in the trivalent state. The thickness of the layer increases with the applied potential as well as with the time the passivating potential is applied to the sample. These results, compared with the electrochemical data, lead to the suggestion that the passive behaviour is not due to the whole oxidic layer but due to a thin, low lying interfacial layer with a structural disorder.

Monte Carlo calculation of free energy for a fcc lattice-gas model

1990

A face-centered-cubic Ising lattice-gas model with nearest- and next-nearest-neighbor interactions is studied, and an accurate determination of the transition temperature for the discontinuous order-disorder transition is obtained. This model is of interest in the studies of phase diagrams for metallic alloys. The location of the transition was previously not known accurately, and its estimation has a number of applications. Very accurate absolute free-energy densities for the two coexisting phases have been obtained from a combination of the standard thermodynamic integration method and the method of sampling finite-size dependence. The latent-heat also is calculated with good precision.

AGV-served assembly lines: influence of sequencing and launch policies on system performances

1990

SUMMARY The planning of an AGV-based flexible assembly line is studied. The conflicting objectives of the minimization of the AGVs wait along the line and of the maximization of the system productivity are investigated. To improve the system performances the late start policy to launch and transfer the AGVs is introduced and a heuristic sequencing algorithm is proposed. The developed computer-aided planning procedures make it possible to consider different AGV launch policies, buffer capacities and management goals; moreover, with the combined use of effective sequences a better utilization of the different resources is reached.

ortho-metallation of P(m-MeC6H4)3 in dirhodium(II) tetraacetate. Molecular structure of Rh2(O2CCH3)2[(m-MeC6H3)P(m-MeC6H4)2]2(HO2CCH3)2·CH3CO2H

1990

Abstract The thermal reaction of Rh2(O2CCH3)4(MeOH)2 and P(m-MeC6H4)3 in a 1:2 molar ratio in acetic acid yielded Rh2(O2CCH3)2[(m-MeC6H3)P(m -MeC6H4)2]2(HO2CCH3)2. Purple monoclinic crystals of this compound and one molecule of acetic acid, space group P21/c, were obtained by evaporation of a solution of the original reaction product in acetic acid/CH2Cl2 mixture. The unit cell parameters are a = 21.346(3), b = 11.909(2), c = 20.071 A, β = 97.98(1)° and Z = 4. The structure consists of a dinuclear rhodium core bridged by cisoid acetate groups and two ortho-metallated phosphine ligands. The ortho-metallation occurs at the least sterically hindered carbon atom which is trans to the methyl sub…

Membrane potential of rat calvaria bone cells: dependence on temperature.

1990

The membrane potentials of bone cells derived from calvaria of new born rats was shown to be strongly dependent on temperature. When we lowered the temperature from 36 degrees C to 26 degrees C, cells with spontaneous resting membrane potentials (MP) of -80 to -50 mV depolarized (mean amplitude 8 mV; n = 33), and the membrane resistance increased by approximately 80% (n = 20). The temperature response depended on the actual MP, the reversal potential being in the range of -80 to -90 mV. With the application of ouabain (0.1-1 mmol/liter; n = 12), cells depolarized. Simultaneously, the reversal potential of the temperature response was shifted towards more positive values and approached the a…

Finite-element design sensitivity analysis for non-linear potential problems

1990

Design sensitivity analysis is performed for the finite-element system arising from the discretization of non-linear potential problems using isoparametric Lagrangian elements. The calculated sensitivity formulae are given in a simple matrix form. Applications to the design of electromagnets and airfoils are given.

Urinary glycosaminoglycans in Graves' ophthalmopathy.

1990

An increased accumulation of glycosaminoglycans (GAG) in retrobulbar tissues has been reported in patients with thyroid eye disease. We examined the quantitative urinary GAG excretion in 101 patients with Graves' ophthalmopathy of different classes, 36 patients with Graves' hyperthyroidism without ophthalmopathy, 14 patients with toxic nodular goitre and 103 control subjects. Glycosaminoglycans were isolated from 24-h urine collections by precipitation with cetylpyridinium chloride and ethanol followed by photometrical quantification of hexuronic acids after reaction with carbazole. In comparison with the control group (15.8, 10.4, 21.6 mg/24 h; median, 25th, 75th percentile) a significant …

Gluonic contributions in the chiral hyperbag

1990

Abstract We incorporate into a non-perturbative chiral bag model scheme the gluons and the η' in a perturbative fashion. We analyze in this context the proton matrix element for the flavor singlet axial current, where due account is taken of the anomaly, and the delta-nucleon mass difference. Our results show that the contribution due to the gluons is significant for large bag radii and that they are crucial in order to establish the Cheshire cat principle.

Sex differences in GABAA receptor binding in rat brain measured by an improved in vitro binding assay.

1990

The distribution of GABAA receptor sites was studied in female and male rat brain by an improved in vitro binding assay using 3H-muscimol and carefully washed membrane fractions. The binding studies revealed a single class of binding sites exhibiting the properties of GABAA receptors. The specific binding of 3H-muscimol was measured in four brain areas: the preoptic brain area, mediobasal hypothalamus, corticomedial amygdala and cerebral cortex. The equilibrium dissociation constants (KD) ranged from 11.2 to 23.3 nM in diestrous females and from 13.1 to 50.4 nM in males, the maximal number of binding sites (Bmax) from 3290 to 10240 fmol/mg protein in females and from 5495 to 17449 fmol/mg p…

Experimental multichannel recognition capability of polychromatic objects using optical correlators

1990

Polychromatic object recognition by multichannel correlation is experimentally achieved. Model objects whose shape changes with the wavelength of the illumination beam were used. Highpass matched filters were employed. The results confirm previous numerical simulations 1.

Killer toxin of Hanseniaspora uvarum

1990

The yeast Hanseniaspora uvarum liberates a killer toxin lethal to sensitive strains of the species Saccharomyces cerevisiae. Secretion of this killer toxin was inhibited by tunicamycin, an inhibitor of N-glycosylation, although the mature killer protein did not show any detectable carbohydrate structures. Culture supernatants of the killer strain were concentrated by ultrafiltration and the extracellular killer toxin was precipitated with ethanol and purified by ion exchange chromatography. SDS-PAGE of the electrophoretically homogenous killer protein indicated an apparent molecular mass of 18,000. Additional investigations of the primary toxin binding sites within the cell wall of sensitiv…

Pituitary-adrenal responses to corticotropin-releasing factor in late onset 21-hydroxylase deficiency

1990

Intravenous corticotropin-releasing factor (CRF) and adrenocorticotropin hormone (ACTH) were administered in patients with adult onset 21-hydroxylase deficiency to compare their diagnostic capability as well as to investigate hypothalamic-pituitary-adrenal function in this disorder. Responses of 17-hydroxyprogesterone, which were markedly elevated compared with controls, were identical with CRF and ACTH. However, intravenous ACTH resulted in higher androstenedione levels in comparison to CRF. Adrenocorticotropin hormone also resulted in decreased cortisol responses, confirming a defect in steroidogenesis, a finding that was not evident with CRF. Plasma ACTH responses to CRF were similar in …

Incoherent optical correlator

1990

A nonconventional setup based on the Lau effect is employed for implementing a lensless incoherent correlator of 2-D signals with compact support.

Diabetic 3rd nerve palsy: evidence for a mesencephalic lesion.

1990

Eleven consecutive adult chronic diabetic patients presented with an isolated 3rd nerve palsy (8 with pupillary sparing) of which 10 had abnormal ipsilateral or bilateral masseter reflexes (MassR). Three patients had an MRI lesion in the ipsilateral oculomotor fasciculus and 3 had subsequent mild brainstem signs. An additional 13 patients with Weber's syndrome had similar ipsilateral or bilateral MassR abnormalities, while 7 patients with 3rd nerve palsies on a known extra-axial basis had none. The findings suggest that an isolated diabetic 3rd nerve palsy, with or without pupillary sparing, is much more likely on the basis of a focal mesencephalic infarct than a peripheral nerve lesion.

Effects of intermittent high frequency electrical stimulation on denervated EDL muscle of rabbit.

1990

This study was performed to determine whether electrical stimulation can retard denervation-induced changes. The denervated extensor digitorum longus of the rabbit, a fast-twitch muscle, was stimulated at a rate mimicking its motoneuron firing pattern. The 100-Hz stimulation given intermittently subjected the muscle to a low mean total daily frequency of 1.6 Hz. Four weeks of stimulation resulted in no effect upon the denervated stimulated muscle. This stimulation protocol, therefore, is unable to substitute for the lost neuronal influence of the nerve. The muscle contralateral to the stimulated side showed physiological changes making it unsuitable to serve as a control.

Assessment of local cellular immunity in lung cancer by bronchoalveolar lavage.

1990

Small cell lung cancer (SCLC) is the most malignant of the pulmonary neoplasms and is associated with a poor local cellular immune response. 16 patients with non small cell lung cancer (NSCLC) and 11 patients with SCLC underwent bronchoalveolar lavage (BAL) in the lung which harbored the tumor in order to investigate the lymphocyte surface antigens utilizing the immunoperoxidase technique. Analysis of blood lymphocytes was performed in parallel. 8 patients with previous sarcoidosis in complete remission who underwent BAL and 10 normal blood donors served as controls. Among blood lymphocytes the CD3+, CD4+ and CD16+ cell populations were elevated significantly and the T4/T8 ratio was elevate…

Investigation of the dynamics of bacteriorhodopsin

1990

Bacteriorhodopsin (bR) converted to the blue form by deionization has been reconstituted to the active purple membrane by addition of57Fe ions. Mossbauer spectra measured in a wide temperature range reveal Fe3+ binding places with oxygen atoms in the neighbourhood. No evidence for a well defined functional binding place of the iron has been found. On a timescale faster 100 ns the purple membrane shows increasing flexibility above 200 K. In order to analyse the influence of the lipids, a bacteriorhodopsin sample where the lipid content has been increased artificially by the incorporation of DMPC as well as a sample consisting of lipid bilayer have been investigated.

β-process of supercooled o-terphenyl: a comparison of dielectrical and NMR data guided by mode-coupling theory

1990

Abstract According to predictions of mode-coupling theory of the liquid-glass transition, a Cole-Cole dynamical susceptibility is applied to the β-relaxation of supercooled o -terphenyl as studied by 2 H NMR spin-lattice relaxation and by dielectrical relaxation. A temperature-dependent amplitude (1- f ) is assumed for the β-process which yields a description of the NMR data consistent with the dielectrical data. The plateau value f separating the α- and β-processes in the two-step correlation function reveals a similar temperature dependence as compared to the Debye-Waller factor.

Mechanism of brittle fracture in a ductile 316 alloy during stress corrosion

1990

Abstract The ductile f.c.c. 316 alloy is shown to exhibit brittle transgranular (and intergranular) stress corrosion cracking in a 153°C MgCl2 solution at free corrosion potential. Tests on smooth and pre-cracked specimens are performed to identify the mechanisms of fracture. Transgranular cracking is related to both a discontinuous microcleavage mainly on {100} planes and a microshearing on {111} planes. A new physical modelization is proposed to explain the brittle transgranular cracking. It is based on the influence of the localized anodic dissolution on the enhancement of the plasticity at the crack tip. The formation of dislocation pile-ups and the conditions of restricted slip induce …

Advances in Mössbauer Emission Spectroscopy

1990

After effects following nuclear transformation have been extensively studied in a large variety of matrices by Mossbauer Emission Spectroscopy (MES). The branching ratios of transient atomic charge states and energetically unstable states of the environment, excitations of electronic ligand field states and populations out of equilibrium within the electronic ground state manifold have been studied. Recent developments and also new insights and understandings of different aspects of the aftereffects of radioactive decay of57Co in semiconductors and molecular crystals are reviewed. A detailed picture of the decay process within the electronic states of the nucleogenic Fe3+ species could be o…