Stationary spatially periodic and aperiodic solutions in membrane reactors

The formation of stationary spatially patterns is analysed for a detailed reaction mechanism of the oxidative dehydrogenation of ethane. In the first step, a simple steady-state model of an ideal plug flow membrane reactor is investigated by numerical bifurcation analysis. The model shows a complex nonlinear behaviour including period doubling bifurcations and aperiodic spatial patterns. In the next step, the influence of axial heat dispersion is studied. Finally, a more detailed model of a fixed bed membrane reactor is considered. It is found that pattern formation is possible under operation conditions realisable in a laboratory reactor.     

James and the physical basis of emotion: A comment on Ellsworth.

It is argued that P. Ellsworth's (1994) interpretation of William James's theory of emotions is not supported by his writings. On the basis of textual evidence and systematic considerations, the authors try to show that, in line with the traditional view, James's theory holds that emotions are identical with feelings of bodily changes, of which autonomic changes are by far the most important ones (i.e., the only ones necessary and sufficient for emotions). Furthermore, the authors argue that James's question of the temporal priority of emotions versus bodily feelings makes good sense even if one acknowledges that these events usually show temporal overlap. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Chemokines and receptors in HIV encephalitis

BACKGROUND: Chemokines are involved in the migration of leukocytes and have been implicated in several inflammatory diseases of the central nervous system. Some of their receptors have been proposed to mediate HIV infection. OBJECTIVE: To determine changes in chemokine and receptor expression in HIV encephalitis, and to determine whether upregulation leads to recruitment of infected monocytes across the blood-brain barrier and participates in HIV neuropathology. METHODS: Immunocytochemistry and double-label immunofluorescent laser confocal microscopy was performed with antibodies to chemokines and their receptors on brain tissues from patients who died with or without HIV encephalitis. In vivo distribution was compared with in vitro cultures of human neuroglial cells. RESULTS: The beta-chemokines monocyte chemotactic protein-1, macrophage inflammatory protein-1alpha, and RANTES were detected on brain macrophages. Their presence was associated with the histopathological signs of HIV encephalitis. The alpha-chemokines IP-10 (10 kDa inflammatory protein) and interleukin-8 were expressed by astrocytes in all tissues, including controls. Presence of the CXC-chemokine receptor (CXCR)-4 was seen on brain macrophages/microglia, neurons, and astrocytes. CC-Chemokine receptor (CCR)-5 was detected only on macrophages/microglia. CCR-3 and CCR-1 were expressed by macrophages and endothelial cells. In vitro studies examining the presence of CCR-3, CCR-5, and CXCR-4 on human brain cell cultures demonstrated abundant neuronal and microglial expression. CONCLUSIONS: Expression of a variety of chemokines and receptors was shown to be increased in HIV encephalitis brain tissues particularly in areas of neuroglial reaction. The expression pattern supported their involvement in the recruitment of inflammatory infiltrates and formation of microglial nodules. Presence of chemokine receptors on neurons may be involved in the pathogenesis of neurologic damage in AIDS patients.     

Anwendung der analytischen Größenausschluß-Chromatographie zur Untersuchung des Substratahbaus einer kommerziellen Pektatlyase ausErwinia carotovora

Within the scope of the characterization of a commercial pectate lyase (PAL) the pattern of substrate degradation by that enzyme was investigated with oligogalacturonic acids as well as pectins with various degrees of esterification as substrates. For this purpose an analytical size exclusion chromatographie method (HPSEC) was elaborated in order to evaluate the reaction products of the degraded substrates over the whole range of molecular weight with the main interest lying in the emerging oligogalacturonic acids. The degradation of polygalacturonic acid by PAL was additionally investigated by means of thin-layer chromatography (TLC) and viscosimetry. Furthermore spontaneous depolymerization and deesterification of the substrates occurring under the chosen conditions were examined. The PAL showed to be anendo-enzyme both by means of TLC and HPSEC. Polygalacturonic acid was broken down, mainly generating unsaturated tri- and digalacturonic acid; the corresponding monomer was not found. The mode of cleavage is discussed.     

Three generations of cyclosporine a formulations: an in vitro comparison

When the microemulsion formulation of the critical dose drug cyclosporine A (CsA) (Sandimmun Optoral) was introduced in the mid-1990s, it became clear that this new formulation improves the oral bioavailability of CsA and has a positive influence on its pharmacokinetic variability. Previous studies with the original CsA formulation (Sandimmun) showed that the size of the emulsion droplets and concomitant food intake has an effect on the absorption of CsA from the small intestine when orally administered. It was suggested that these effects might have an influence on the drugs' pharmacokinetic parameters.In this study, we focused on the two above-mentioned aspects and compared the first and second generations of CsA products (Sandimmun, Sandimmun Optoral) to generic CsA formulations by analyzing the contents of cyclosporine A gel capsules with respect to their emulsion droplet and micelle sizes using photon correlation spectroscopy (PCS). We tried to discern any differences in droplet size between different generations of CsA formulations, primarily the second and third generation, through simple physical tests. Because a high fat content food may influence the absorption of CsA, we also determined the distribution of CsA between hydrophilic and lipophilic phases using high-performance liquid chromatography analysis.It became clear that when compared under simple physical conditions, established cyclosporine formulations and new generic products show significant differences in droplet size and distribution between an aqueous phase and a high fat content food. Whether these differences are of clinical relevance remains to be investigated.     

Discovery of Riociguat (BAY 63‐2521): A Potent,Oral Stimulator of Soluble Guanylate Cyclase for the Treatment of Pulmonary Hypertension

Direct stimulation of soluble guanylate cyclase (sGC) represents a promising therapeutic strategy for the treatment of a range of diseases, including the severely disabling pulmonary hypertension (PH). Optimization of the unfavorable DMPK profile of previous sGC stimulators provided riociguat, which is currently being investigated in phase III clinical trials for the oral treatment of PH.

     

Doping Molecular Monolayers: Effects on Electrical Transport Through Alkyl Chains on Silicon

n‐Si/C_nH_{2n + 1}/Hg junctions (n = 12, 14, 16 and 18) can be prepared with sufficient quality to assure that the transport characteristics are not anymore dominated by defects in the molecular monolayers. With such organic monolayers we can, using electron, UV and X‐ray irradiation, alter the charge transport through the molecular junctions on n‐ as well as on p‐type Si. Remarkably, the quality of the self‐assembled molecular monolayers following irradiation remains sufficiently high to provide the same very good protection of Si from oxidation in ambient atmosphere as provided by the pristine films. Combining spectroscopic (UV photoemission spectroscopy (UPS), X‐ray photoelectron spectroscopy (XPS), Auger, near edge‐X‐ray absorption fine structure (NEXAFS)) and electrical transport measurements, we show that irradiation induces defects in the alkyl films, most likely C?C bonds and C? C crosslinks, and that the density of defects can be controlled by irradiation dose. These altered intra‐ and intermolecular bonds introduce new electronic states in the highest occupied molecular orbital (HOMO)–lowest unoccupied molecular orbital (LUMO) gap of the alkyl chains and, in the process, dope the organic film. We demonstrate an enhancement of 1–2 orders of magnitude in current. This change is clearly distinguishable from the previous observed difference between transport through high quality and defective monolayers. A detailed analysis of the electrical transport at different temperatures shows that the dopants modify the transport mechanism from tunnelling to hopping. This study suggests a way to extend significantly the use of monolayers in molecular electronics.