Simultaneous Changs in Striatal Dopamin,Serotonin,and Metabolites After Withdrawal Seizures in Rats From Dependence on Alcohol

Mirovsky,Y.,Goldberg,M.,Fisher,H.,Sekowski,A.,Wagner,G.C. 이화여자대학교 가정과학대학 식품영양학과 아시아 식품영양연구소 1999 食品營養情報 Vol.- No.9

Ethanol dependence was achieved in male. Long-Evans rats after 8 days on a balanced liquid diet that supplied 4.5% ethanol. After 1-h access to a solution of 10% ethanol (95%)/5% sucrose, the rats were deprived of food, water, and ethanol for 9 h. Following 30-s key jingling, about 80% of the animals exposed to ethanol experienced tonic-clonic seizures. Neurochemical analyses of striatal tissues revealed a significant (p<0.05) increase in dopamine (DA) and a significant decrease in serotonin (5-HT) in the ethanol-exposed rats that had seizures compared to control rats. Homovanillic acid concentrations of the ethanol-treated rats with seizures were significantly higher than the levels found in ethanol-treated animals that had experienced no seizures. Daily average ethanol intake of the rats that had seizures vs. those that did not was almost the same at 16 g/kg/day. The findings indicate that rats experiencing ethanol withdrawal-induced seizures manifest opposite alterations in dopaminergic and serotoninergic activity compared to controls. The present results do not reveal if the striatal changes are caused by ethanol rather than by the seizures.

Imaging Neuror eceptors in the Living Human Brain

Wagner, Henry N.,Dannals, Robert F.,Frost, J. James,Wong, Dean F.,Ravert, Hayden T.,Wilson, Alan A.,Links, Jonathan M.,Burns, H. Donald,Kuhar, Michael J.,Snyder, Solomon H. 대한핵의학회 1984 핵의학 분자영상 Vol.18 No.2

Nonlinear rheology of linear polymer melts: Modeling chain stretch by interchain tube pressure and Rouse time

Wagner, Manfred H.,Rolon-Garrido, Victor H. The Korean Society of Rheology 2009 Korea-Australia rheology journal Vol.21 No.4

In flows with deformation rates larger than the inverse Rouse time of the polymer chain, chains are stretched and their confining tubes become increasingly anisotropic. The pressures exerted by a polymer chain on the walls of an anisotropic confinement are anisotropic and limit chain stretch. In the Molecular Stress Function (MSF) model, chain stretch is balanced by an interchain pressure term, which is inverse proportional to the $3^{rd}$ power of the tube diameter and is characterized by a tube diameter relaxation time. We show that the tube diameter relaxation time is equal to 3 times the Rouse time in the limit of small chain stretch. At larger deformations, we argue that chain stretch is balanced by two restoring tensions with weights of 1/3 in the longitudinal direction of the tube (due to a linear spring force) and 2/3 in the lateral direction (due to the nonlinear interchain pressure), both of which are characterized by the Rouse time. This approach is shown to be in quantitative agreement with transient and steady-state elongational viscosity data of two monodisperse polystyrene melts without using any nonlinear parameter, i.e. solely based on the linear-viscoelastic characterization of the melts. The same approach is extended to model experimental data of four styrene-butadiene random copolymer melts in shear flow. Thus for monodisperse linear polymer melts, for the first time a constitutive equation is presented which allows quantitative modeling of nonlinear extension and shear rheology on the basis of linear-viscoelastic data alone.

Chemistry, Biosynthesis and Pharmacology of Flavanolignans

H. Wagner 한국생약학회 1978 생약학회지 Vol.9 No.1

Nonlinear rheology of polymer melts: a new perspective on finite chain extensibility effects

Wagner Manfred H. The Korean Society of Rheology 2006 Korea-Australia rheology journal Vol.18 No.4

Measurements by Luap et al. (2005) of elongational viscosity and birefringence of two nearly monodisperse polystyrene melts with molar masses $M_{w}$ of $206,000g{\cdot}mol^{-1}$ (PS206k) and $465,000g{\cdot}mol^{-1}$ (PS465k) respectively are reconsidered. At higher elongational stresses, the samples showed clearly deviations from the stress optical rule (SOR). The elongational viscosity data of both melts can be modeled quantitatively by the MSF model of Wagner et al. (2005), which is based on the assumption of a strain-dependent tube diameter and the interchain pressure term of Marrucci and Ianniruberto (2004). The only nonlinear parameter of the model, the tube diameter relaxation time, scales with $M_{w}^{2}$. In order to get agreement with the birefringence data, finite chain extensibility effects are taken into account by use of the $Pad\'{e}$ approximation of the inverse Langevin function, and the interchain pressure term is modified accordingly. Due to a selfregulating limitation of chain stretch by the FENE interchain pressure term, the transient elongational viscosity shows a small dependence on finite extensibility only, while the predicted steady-state elongational viscosity is not affected by non-Gaussian effects in agreement with experimental evidence. However, deviations from the SOR are described quantitatively by the MSF model by taking into account finite chain extensibility, and within the experimental window investigated, deviations from the SOR are predicted to be strain rate, temperature, and molar mass independent for the two nearly monodisperse polystyrene melts in good agreement with experimental data.

Constitutive equations for polymer mole and rubbers: Lessons from the $20^{th}$ century

Wagner, Manfred H. The Korean Society of Rheology 1999 Korea-Australia rheology journal Vol.11 No.4

Refinements of classical theories for entangled or crosslinked polymeric systems have led to incommensurable models for rubber networks and polymer melts, contrary to experimental evidence, which suggests a great deal of similarity. Uniaxial elongation and compression data of linear and branched polymer melts as well as of crosslinked rubbers were analyzed with respect to their nonlinear strain measure. This was found to be the result of two contributions: (1) affine orientation of network strands, and (2) isotropic strand extension. Network strand extension is caused by an increasing restriction of lateral movement of polymer chains due to deformation, and is modelled by a molecular stress function which in the tube concept of Doi and Edwards is the inverse of the relative tube diameter. Up to moderate strains, $f^2$ is found to be linear in the average stretch for melts as well as for rubbers, which corresponds to a constant tube volume. At large strains, rubbers show maximum extensibility, while melts show maximum molecular tension. This maximum value of the molecular stress function governs the ultimate magnitude of the strain-hardening effect of linear and long-chain branched polymer melts in extensional flows.

통일대비 : 특별기고2 ; 헬무트 바그너 : 독일 통일을 부정한 이해관계,선입견,이데올르기

헬무트바그너 ( H. Wagner ) 평화문제연구소 2009 통일한국 Vol.306 No.-

Nonlinear rheology of polymer melts: a new perspective on finite chain extensibility effects

Manfred H. Wagner 한국유변학회 2006 Korea-Australia rheology journal Vol.18 No.4

Measurements by Luap et al. (2005) of elongational viscosity and birefringence of two nearly monodisperse polystyrene melts with molar masses MW of 206,000gmol1 (PS206k) and 465,000gmol1 (PS465k) respectively are reconsidered. At higher elongational stresses, the samples showed clearly deviations from the stress optical rule (SOR). The elongational viscosity data of both melts can be modeled quantitatively by the MSF model of Wagner et al. (2005), which is based on the assumption of a strain-dependent tube diameter and the interchain pressure term of Marrucci and Ianniruberto (2004). The only nonlinear parameter of the model, the tube diameter relaxation time, scales with MW2. In order to get agreement with the birefringence data, finite chain extensibility effects are taken into account by use of the Pad approximation of the inverse Langevin function, and the interchain pressure term is modified accordingly. Due to a self-regulating limitation of chain stretch by the FENE interchain pressure term, the transient elongational viscosity shows a small dependence on finite extensibility only, while the predicted steady-state elongational viscosity is not affected by non-Gaussian effects in agreement with experimental evidence. However, deviations from the SOR are described quantitatively by the MSF model by taking into account finite chain extensibility, and within the experimental window investigated, deviations from the SOR are predicted to be strain rate, temperature, and molar mass independent for the two nearly monodisperse polystyrene melts in good agreement with experimental data.

Nonlinear rheology of linear polymer melts: Modeling chain stretch by interchain tube pressure and Rouse time

Manfred H. Wagner,Víctor H. Rolón-Garrido 한국유변학회 2009 Korea-Australia rheology journal Vol.21 No.4

In flows with deformation rates larger than the inverse Rouse time of the polymer chain, chains are stretched and their confining tubes become increasingly anisotropic. The pressures exerted by a polymer chain on the walls of an anisotropic confinement are anisotropic and limit chain stretch. In the Molecular Stress Function (MSF) model, chain stretch is balanced by an interchain pressure term, which is inverse proportional to the 3rd power of the tube diameter and is characterized by a tube diameter relaxation time. We show that the tube diameter relaxation time is equal to 3 times the Rouse time in the limit of small chain stretch. At larger deformations, we argue that chain stretch is balanced by two restoring tensions with weights of 1/3 in the longitudinal direction of the tube (due to a linear spring force) and 2/3 in the lateral direction (due to the nonlinear interchain pressure), both of which are characterized by the Rouse time. This approach is shown to be in quantitative agreement with transient and steady-state elongational viscosity data of two monodisperse polystyrene melts without using any nonlinear parameter, i.e. solely based on the linear-viscoelastic characterization of the melts. The same approach is extended to model experimental data of four styrene-butadiene random copolymer melts in shear flow. Thus for monodisperse linear polymer melts, for the first time a constitutive equation is presented which allows quantitative modeling of nonlinear extension and shear rheology on the basis of linear-viscoelastic data alone.

Role of platelet CD40 ligand for endothelial cell-monocyte interaction in the presence of flow

Andreas H. Wagner,Manuel Schwarz,Gerd König,Markus Hecker 한국유변학회 2014 Korea-Australia rheology journal Vol.26 No.4

CD40 ligand (CD154)-induced ultra-large von Willebrand factor (vWF) multimer-mediated endothelial cellplatelet-monocyte interaction may play an important role in adaptive and maladaptive vascular remodelingprocesses. Here we analyzed the impact of and conditions favouring the deposition of these multimers onthe endothelial cell (EC) surface by way of CD40-CD154 co-stimulation in settings mimicking differentforms of blood flow. Upon exposure to low oscillatory shear stress and sCD154, a release of vWF multimerscomparable to histamine stimulation was monitored on the EC surface in a string-like fashion. Moreover,ex vivo perfused carotid arteries of wild type mice at low laminar shear stress rates showed a luminalrelease of vWF as ultra-large vWF multimers (ULVWF) upon stimulation with sCD154 which was absentin blood vessels of CD40 knockout mice. The observed CD40- and flow-dependent vWF release from intactendothelial cells and subsequent vWF multimer formation may facilitate adhesion and subsequent activationof circulating platelets at atherosclerotic predilection sites, which are characterized by disturbed flow patterns. This in turn may amplify endothelial cell-monocyte interaction, thus possibly initiating or promotingearly atherosclerotic lesion formation.