Showing papers by "Solvay published in 2001"

4,5-dihydro-1H-pyrazole derivatives having CB1-antagonistic activity

Abstract: The present invention relates to a group of novel 4,5-dihydro-1H-pyrazole derivatives having S configuration at the 4-position of their 4,5-dihydro pyrazole ring which are potent antagonists of the cannabis CB1-receptorThe compounds have the general formula (I) wherein- R and R1 are the same or different and represent 3-pyridyl or 4-pyridyl or phenyl which may be substituted with halogen or methoxy,- R2 and R3 are the same or different and represent hydrogen, alkyl (1-3 C) or dimethylamino- R4 represents phenyl which may be substituted with 1 or 2 substituents selected from the group halogen atoms, trifluoromethyl, methoxy and alkyl (1-3 C)and tautomers, prodrugs and salts thereofThese enantiomers are much more potent and selective antagonists of the cannabis CB1-receptor, than the other enantiomer

Reactive oxygen species enhance the migration of monocytes across the blood-brain barrier in vitro

Abstract: Reactive oxygen species (ROS) are involved in the pathogenesis of several inflammatory and degenerative diseases, including multiple sclerosis (MS), an inflammatory disease of the central nervous system. We investigated the potential involvement of ROS in the interaction of monocytes with cerebral endothelium, because this is likely to be an early event in the development of MS lesions. ROS are produced via two main pathways, one involving NADPH oxidase complex and the other involving xanthine oxidase (XO). We examined the effects of ROS, ROS scavengers, and ROS inhibitors of both pathways on the migration of monocytes across the blood-brain barrier in vitro. Scavengers and inhibitors of XO predominantly inhibited monocyte migration, whereas inhibitors and scavengers of the NADPH oxidase complex had no effect. Exposure of cerebral endothelial cells (CEC) to superoxide (O 2 - ) resulted in enhanced migration and adhesion of monocytes as well as disruption of the tight junctions, whereas hydroxyl radicals and hydrogen peroxide induced no significant effect on these parameters. Underlying mechanisms of the observed changes were found to reside in the phospholipase Cmediated signal transduction cascade, subsequent accumulation of inositol 1,4,5-trisphosphate, and mobilization of intracellular calcium. We conclude that O 2 - is a signaling molecule that is

Superinflation, quintessence, and nonsingular cosmologies

Abstract: The dynamics of a universe dominated by a self-interacting nonminimally coupled scalar field are considered. The structure of the phase space and complete phase portraits are given. New dynamical behaviors include superinflation ($\dot{H}>0$), avoidance of big bang singularities through classical birth of the universe, and spontaneous entry into and exit from inflation. This model is promising for describing quintessence as a nonminimally coupled scalar field.

The endosomal compartment is an insulin-sensitive recruitment site for GLUT4 and GLUT1 glucose transporters in cardiac myocytes.

Abstract: In nonstimulated cardiomyocytes, the glucose transporter GLUT4 is confined to intracellular vesicles forming at least two populations: a storage pool enriched in GLUT4 (pool 1) and an endosomal pool containing both GLUT4 and GLUT1 (pool 2). We have now studied the dynamics of these pools in response to insulin or the mitochondrial inhibitor rotenone in rat cardiomyocytes. Rotenone recruited GLUT4 and GLUT1 to the cell surface from endosomal pool 2 without affecting pool 1. Kinetic experiments were consistent with rotenone acting on an intracellular compartment that is in close connection with the plasma membrane. In contrast, insulin caused rapid, complete depletion of GLUT4 from pool 1 and reduced the GLUT1 content of pool 2 by approximately 50%, whereas, surprisingly, no net decrease in GLUT4 occurred in this pool. Subsequent insulin withdrawal resulted in slow replenishment of pool 2 with GLUT1 and of pool 1 with GLUT4. When pool 1 was still largely depleted of GLUT4, a second insulin challenge did red...

Immunohistochemical detection of estrogen receptor α in articular chondrocytes from cows, pigs and humans: in situ and in vitro results

Abstract: Clinical observations suggest that estrogens are involved in the pathogenesis of postmenopausal osteoarthritis, but only little is known about the influence of these hormones on articular cartilage cells. The effect of estradiol is mediated by estrogen receptors alpha and beta. The goal of the present study was to search for estrogen receptor alpha in articular tissue from cows, pigs and humans by immunohistochemistry to form a basis for in vitro studies. In addition, we also tried to detect estrogen receptor alpha in cultivated articular chondrocytes from cows and bulls under certain culture conditions. Estrogen receptor alpha is detected by the use of antibody 13H2 in articular chondrocytes from cows, bulls, pigs and humans. Chondrocytes are physiologically exposed to reduced oxygen tension. In isolated articular chondrocytes from cows and bulls incubated either with 21% O2 or with 5% O2 positive cells were also found. These positive results therefore encourage testing the influence of estradiol on cultivated articular cartilage cells in these species under different culture conditions.

Quantum transitions and dressed unstable states

Abstract: We consider the problem of the meaning of quantum unstable states including their dressing. According to both Dirac and Heitler this problem has not been solved in the usual formulation of quantum mechanics. A precise definition of excited states is still needed to describe quantum transitions. We use our formulation given in terms of density matrices outside the Hilbert space. We obtain a dressed unstable state for the Friedrichs model, which is the simplest model that incorporates both bare and dressed quantum states. The excited unstable state is derived from the stable states through analytic continuation. It is given by an irreducible density matrix with broken time symmetry. It can be expressed by a superposition of Gamow density operators. The main difference from previous studies is that excited states are not factorizable into wave functions. The dressed unstable state satisfies all the criteria that we can expect: it has a real average energy and a nonvanishing trace. The average energy differs from Green's function energy by a small effect starting with fourth order in the coupling constant. Our state decays following a Markovian equation. There are no deviations from exponential decay neither for short nor for long times, as ismore » the case for the bare state. The dressed state satisfies an uncertainty relation between energy and lifetime. We can also define dressed photon states and describe how the energy of the excited state is transmitted to the photons. There is another very important aspect: deviations from exponential decay would be in contradiction with indiscernibility as one could define, e.g., old mesons and young mesons according to their lifetime. This problem is solved by showing that quantum transitions are the result of two processes: a dressing process, discussed in a previous publication, and a decay process, which is much slower for electrodynamic systems. During the dressing process the unstable state is prepared. Then the dressed state decays in a purely exponential way. In the Hilbert space the two processes are not separated. Therefore it is not astonishing that we obtain for the unstable dressed state an irreducible density matrix outside the Liouville-Hilbert-space. This is a limit of Hilbert space states that are arbitrarily close to the decaying state. There are experiments that could verify our proposal. A typical one would be the study of the line shape, which is due to the superposition of the short-time process and the long-time process. The long-time process taken separately leads to a much sharper line shape, and avoids the divergence of the fluctuation predicted by the Lorentz line shape.« less

Space-time formulation of quantum transitions

Abstract: In a previous paper we have studied dressed excited states in the Friedrichs model, which describes a two-level atom interacting with radiation. In our approach, excited states are distributions (or generalized functions) in the Liouville space. These states decay in a strictly exponential way. In contrast, the states one may construct in the Hilbert space of wave functions always present deviations from exponential decay. We have considered the momentum representation, which is applicable to global quantities (trace, energy transfer). Here we study the space-time description of local quantities associated with dressed unstable states, such as, the intensity of the photon field. In this situation the excited states become factorized in Gamow states. To go from local quantities to global quantities, we have to proceed to an integration over space, which is far from trivial. There are various elements that appear in the space-time evolution of the system: the unstable cloud that surrounds the bare atom, the emitted real photons and the ``Zeno photons,'' which are associated with deviations from exponential decay. We consider a Hilbert space approximation to our dressed excited state. This approximation leads already to decay close to exponential in the field surrounding the atom, and to a line shape different from the Lorentzian line shape. Our results are compared with numerical simulations. We show that the time evolution of an unstable state satisfies a Boltzmann-like $\mathcal{H}$ theorem. This is applied to emission and absorption as well as scattering. The existence of a microscopic $\mathcal{H}$ theorem is not astonishing. The excited states are ``nonequilibrium'' states and their time evolution leads to the emission of photons, which distributes the energy of the unstable state among the field modes.

Progress in describing particle growth for polyolefins: a look at particle morphology

Abstract: Discussion focuses on the strengths and weaknesses of current methods of modelling particle growth, and heat and mass transfer during the polymerisation of olefins on supported Ziegler-Natta Catalysts. It is demonstrated that improvements need to be made in the area of mass transfer models in the form of a mechanistic description of particle morphology. Scanning electron microscopy (SEM) is used to examine particle morphology. Simplified models of particle growth demonstrate the need to include convection in gas phase processes and a better description of particle morphology.

Method for the treatment of diabetes

Abstract: The use of physiologically acceptable enzyme mixtures having lipolytic, proteolytica and amylolytic activity, of microbial or animal origin, preferably digestive enzyme mixtures such as pancreatin or digestive enzyme mixtures containing pancreatin, for the treatment of diabetes. The invention also relates to the production of pharmaceutical compositions suitable for such treatment. A preferred variant of the invention relates to use of this enzyme mixture having lipolytic, proteolytic and amylolytic activity, especially digestive enzyme mixtures such as pancreatin or digestive enzyme mixtures containing pancreatin, for the adjuvant treatment of type I or type II diabetes mellitus.

Process for the preparation of aqueous dispersions of fluoropolymers

Abstract: Process for the preparation of a dispersion based on homopolymers/copolymers of tetrafluoroethylene (TFE), said dispersion having a bimodal or multimodal distribution of the particle diameters, wherein the fraction of small particles is in the range 1.5-359 by weight calculated on the dry product; the ratio between the average diameter of the small particles with respect to the average diameter of the dispersion obtained from the polymerization being in the range 0.02-0.6; said process comprising the following essential steps: (a) preparation of an aqueous microemulsion comprising fluorinated surfactants and (per)fluoropolyether oils (PFPE); (b) feeding of the microemulsion into the polymerization reactor; (c) feeding of at least one fluorinated surfactant.

The PVC-rat and other alternatives in microsurgical training.

Abstract: The number of animals used in educational training programs in experimental microsurgery can be reduced by using artificial devices such as the anastomoses device and the MD PVC-Rat Such in vitro methods allow development of technical skills, making the transition to in vivo models much easier

Mass transfer in low‐density xerogel catalysts

Abstract: Texture and morphology of a Pd-Ag/SiO 2 hydrodechlorination low-density xerogel catalyst prepared by a cogelation sol-gel process were characterized in detail to examine mass transfer in such catalysts. The catalyst consists of active Pd-Ag nanocrystallites trapped inside elementary 20 nm microporous silica particles arranged in larger aggregates, which constitute the macroscopic pellet. To reach active sites, reactants must first diffuse through large pores located between aggregates of SiO 2 particles and then through smaller pores located between those elementary particles inside the aggregates. Finally, they diffuse through micropores located inside silica particles. Diffusion in such a funnel structure cannot be described assimilating the pellet to a pseudo-continuum. Diffusion should be examined carefully at three levels of decreasing size: the macroscopic pellet, the aggregate of silica particles, and the elementary silica particle. This approach shows that cogelled xerogel catalysts have remarkable mass-transfer properties.

Quantum Zeno and anti-Zeno effects in the Friedrichs model

Abstract: We analyze the short-time behavior of the survival probability in the frame of the Friedrichs model for different form factors. We have shown that this probability is not necessarily analytic at the time origin. The time when the quantum-Zeno effect could be observed is found to be much smaller than usually estimated. We have also studied the anti-Zeno period and have estimated its duration.

Method for making a bipolar membrane and use of resulting bipolar membrane

Abstract: The invention concerns a method for making a bipolar membrane which consists in: treating a cationic membrane with a group 8 metal salt; treating an anionic membrane with a transition metal salt not belonging to group 8; and conjoining the two membranes, the latter being contacted, before and after being conjoined, with a treatment solution selected among aqueous alkaline solutions, aqueous metallic sulphate solutions and aqueous metallic sulphite solutions.

Platable engineered polyolefin alloys

Abstract: This invention relates to polyolefin alloys that are receptive to metal plating. These compositions also have enhanced properties and are easily processed into articles by various molding methods. The blends of the invention preferably include polyolefin homopolymers or copolymers, acrylonitrile-butadiene-styrene polymers, and a blend of at least one styrene monoolefin copolymer and at least one styrene diolefin copolymer. These blends have excellent platability and superior physical properties including enhanced rigidity, toughness, and dimensional stability.

Perfluoropolyether additives for electrochemical applications

Abstract: Electrolytic compositions comprising a perfluoropolyether additive of formula (I): wherein: d,e,f are integers; a,b,c can be zero or integers; being a+b+ c+d+e+f such that the number average molecular weight ranges from 500 to 5x105; T are end groups -CF2X (X=F,CF3,Cl), -C3F7, -CF(CF3)COO- (1/n)Mn+, -CF2COO- (1/n)Mn+,-CF2C(O(1/n)Mn+)2CF3; Mn+ is a cation having valence n=1-4.

Method for making a fuel tank in plastic material

Abstract: The invention concerns a method for making a fuel tank in plastic material from two shells formed by moulding, which are assembled, the moulding of at least one shell being carried out by compressing part of a plastic sheet (1) between a mould and a punch (5a) and by blowing the remaining part of the sheet, in the non-compressed zone.

Low color poly(biphenyl ether sulfone) and improved process for the preparation thereof

Abstract: Improved carbonate method for producing poly(biphenyl ether sulfones) having a low color, the improvement being the use of small particle size anhydrous potassium carbonate The resulting poly(biphenyl ether sulfones) are significantly improved in color

Explicit construction of a time superoperator for quantum unstable systems

Abstract: A time superoperator T conjugate to the Liouville superoperator LH=[H,] is constructed for a quantum system with one excited state or unstable particle. While there is no time operator conjugate to the Hamiltonian in the wave function space due to the positivity of energy, T may exist in the density matrix space as the spectrum of LH covers all the real axis. This is the first example of an observable that can only be formulated in the Liouville–von Neumann space of density matrices. In our example the expectation value of T gives the lifetime of the unstable particle. Once the time superoperator is obtained it is easy to define an entropy superoperator.