The diastolic debate: is it time to discard Korotkoff phase IV in favour of phase V for blood pressure measurements in pregnancy?

The IgE-mediated allergic response involves a series of physiological pathways that result in the array of symptoms commonly associated with allergy. This article describes the mediators that prompt specific clinical responses and identifies those at risk for latex hypersensitivity.     

Variations in acoustical beam properties of intracoronary Doppler catheters

A foreign gene coding the bacterial enzyme, chloramphenicol acetyltransferase (CAT), was introduced into a primary culture of the mouse cerebellar primordium by a retrovirus vector which harbors the neomycin-resistant gene. Following selection of the gene-transferred cells based on neomycin resistance, most of the selected cells expressed the CAT gene product as well as a marker for astrocytes, glial fibrillary acidic protein (GFAP), when examined immunocytochemically. These cells were transplanted into the adult mouse cerebellum, and the surviving cells were examined immunohistochemically by marking them with anti-CAT antibody. The distribution of CAT-immunopositive cells coincided with that of GFAP-immunopositive cells observed in serial sections of grafted sites at 10 days after transplantation. Some of the transplanted CAT-immunopositive cells extended processes and exhibited the morphological appearance of fibrous astrocytes. Migration of the genetically labeled cells into the host molecular layer was also observed and the morphological plasticity of the differentiated primary cells was shown according to the grafted sites. These results indicate that stable marking of cells for grafting can be accomplished by retrovirus-mediated introduction of a foreign gene into the primary culture, and that the fate and behavior of the labeled donor cells can be analyzed immunohistochemically following transplantation into neural tissue.     

Product-oriented flavor research: learnings from the past, visions for the future

In the past flavor research and the development of new flavorings were constantly driven by the interaction of flavor analysis, structure elucidation, and chemical synthesis accompanied by sensory. Highly potent flavor compounds were identified in numerous food products and helped to establish a powerful toolbox for flavorists. Nowadays we experience the merging of various scientific disciplines, for example medicine, biology, chemistry, and various technologies in the field of flavor research, which shows direct impact on our understanding of flavors. At the same time modern life has profoundly changed our eating habits. This situation generates new challenges for product development teams, which represent all facets of technologies. This paper will illustrate different examples for the evolution of product-oriented flavor research and future trends.     

Differential release of interleukin-6 from human gestational tissues in association with labour and in vitro endotoxin treatment

In this study, we quantified interleukin-6 (IL-6) concentrations in amniotic fluid at term and preterm labour, and determined the gestational tissue source of IL-6. In addition, aspects of the regulatory mechanisms involved in IL-6 release at the time of term labour and in response to bacterial endotoxin, lipopolysaccharide (LPS), have been established. IL-6 concentrations were 2-fold higher in amniotic fluid collected at term compared with preterm gestation, with an additional 2-fold increase in association with term labour. IL-6 was released from all choriodecidual and placental explants but was detected in only 33% of amniotic explant cultures of tissues obtained before labour onset. In contrast, IL-6 was detected in all amniotic, choriodecidual and placental cultures of tissues obtained after term labour onset and delivery, and the mean IL-6 release was significantly higher than that measured in explant cultures of both amniotic (80-fold increase, P < 0.0001) and choriodecidual (3-fold increase, P < 0.02) but not placental explants taken at the time of elective Caesarean section at term before labour onset. LPS significantly (P < 0.05) increased the release of IL-6 from human choriodecidual and placental explants but not amniotic explants, in a time- and dose-dependent manner. IL-6 is a physiological constituent of amniotic fluid and its production by gestational tissues is differentially regulated by LPS and spontaneous labour onset and delivery.     

Impedance measurements of air-oxidized and H2-annealed Raney-Ni catalysts for alkaline fuel cells

The catalytic properties and the long-term performance of Raney-NiTi2 catalysts being used in H₂ electrodes of alkaline H₂---O₂ fuel cells can be significantly improved by slow air oxidation and subsequent annealing in an H₂ atmosphere at 300°C. Individual reaction steps are investigated by means of impedance measurements. Theoretical estimations, on the basis of a simple equivalent circuit of a supported electrode, result in a frequency-response relationship which is in very good agreement with the experimental data referring to the relevant frequency range of 10⁻³−10⁻¹ Hz. A method to evaluate the impedance spectra is described in some detail. Calculated and measured impedance data are in good agreement, thus indicating the validity of the charge transfer resistance, the diffusion resistance, as well as the chemisorption capacity and the double-layer capacity. Experiments on the influence of catalyst annealing in an H₂ atmosphere at 350°C show a strong increase in the charge transfer resistance and an obvious decrease in the diffusion resistance, depending on the annealing time. A similar influence on the chemisorption capacity and the double-layer capacity is not observed.     

Liquid‐liquid phase split in ionic liquid + toluene mixtures induced by CO2

High pressure carbon dioxide was dissolved in ionic liquid + toluene mixtures to obtain the conditions of pressure and composition where a liquid‐liquid phase split occurs at constant temperature. Ionic liquids (ILs) with four different cations paired with the bis(trifluoromethylsulfonyl)imide ([Tf₂N]^?) anion were selected: 1‐hexyl‐3‐methylimidazolium ([hmim]⁺), 1‐hexyl‐3‐methylpyridinium ([hmpy]⁺), triethyloctylphosphonium ([P₂₂₂₈]⁺), and tetradecyltrihexylphosphonium ([P₆₆₆₁₄]⁺). The solubility of CO₂ was measured in the liquid mixtures at temperatures between 298 and 333 K and at pressures up to 8 MPa, or until the second liquid phase appeared, for initial liquid phase compositions of 0.30, 0.50, and 0.70 mole fraction of IL. Ternary isotherms were compared with the binary solubility of CO₂ in each IL and pure toluene. The lowest pressure for separating toluene in a second liquid phase was achieved by decreasing the temperature of the system, increasing the amount of toluene in the initial liquid mixture and using [hmim][Tf₂N]. © 2015 American Institute of Chemical Engineers AIChE J, 61: 2968–2976, 2015     

Chirospecific analysis in essential oil, fragrance and flavor research

Knowledge of the difference in character and intensity of organoleptically important enantiomeric flavor and fragrance components has initiated the development of new analytical and preparative methods for the separation of optical isomers. In recent years, progress in the area of chirospecific analysis has been especially achieved by the development of modified cyclodextrins as a new type of chiral stationary phase. The state of the art in research on inclusion gas chromatography for separating flavor and fragrance substances is presented. Furthermore, this review reports on new results and recent research developments in enantioselective GC analysis.

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Chirospezifische Analyse in der etherischen Öl-, Riechstoff- und Aromastoff-Forschung

Zusammenfassung Neuere Untersuchungen zur Struktur-Wirkungsbeziehung chiraler Riech- und Aromastoffe haben gezeigt, daß spiegelbildisomere Verbindungen charakteristische qualitative und quantitative organoleptische Unterschiede aufweisen. Diese Kenntnisse führten zur Entwicklung leistungsfähiger Methoden zur analytischen und präparativen Trennung von optischen Antipoden. Ein wesentlicher Fortschritt auf dem Gebiet der Enantiomerentrennung optisch aktiver Riech- und Aromastoffe konnte in den letzten Jahren durch die gezielte Einführung modifizierter Cyclodextrine als chirale stationäre Phasen in der Capillargaschromatographie erzielt werden. Der nachfolgende Beitrag gibt einerseits einen Überblick über die Möglichkeiten der Inklusionsgaschromatographie in der Aroma- und Riechstofforschung und zeigt andererseits neueste Forschungsergebnisse auf dem Gebiet der enantioselektiven GC-Analyse auf.

     

Über α-substituierte Phosphonate,XX. Untersuchungen zur C-N-Umlagerung bei Aminomethan-bis-und -tris-phosphorylverbindungen

α-Substituted Phosphonates. XX. Investigations on the C—N-Rearrangement of Aminomethane Bis- and Tris-phosphoryl Compounds Attempts to prepare aminomethane-bis-phosphoryl-compounds of the types 5, 9 and 13 , i.e. with a NH-function on the methin-carbon-atom, yielded independently of the synthetic path in all cases by C-N-rearrangement of a phosphoryl-group the N-phosphorylated aminomethane-phosphonic acid esters 6, 10/11 and 14 . The course of this rearrangement has been studied on characteristic examples.     

Hydrogen evolution of highly porous Raney nickel cathodes in alkaline electrolyte

In order to reduce the high electrical energy demand of alkaline water electrolyzers, the structure of nickel cathodes is improved by using highly porous electrodes hot pressed from carbonyl nickel powders. The performance of such cathodes is further improved by adding very active Raney nickel catalysts. The η,i-characteristics measured at various temperatures and galvanostatic long-term experiments are used to evaluate the operational characteristics of porous nickel cathodes. It may be concluded that porous cathodes with Raney nickel catalysts offer a fair improvement to water electrolysis. In particular, the rather small polarization voltages are of great advantage concerning the energy consumption of an elecrolyzer.