Search results for "Ion temperature"
showing 10 items of 220 documents
Antimykotische Wirkstoffe, Mitt. Chlor-(1-piperazinyl)-1,3,5-triazine
1988
Aus der Umsetzung von Cyanurchlorid (1) mit den Piperazinderivaten 2a–c bei –20 bis 10° gehen die Dichlor-(1-piperazinyl)-1,3,5-triazine 3a–c hervor. Bei der erhohten Reaktionstemperatur von 40° erfolgt aus 1 und den Piperazinderivaten 4a–b Bildung der 2-Chlor-4,6-bis(piperazinyl)-1,3,5-triazine 5a–b. Zu gemischt substituierten Chlor-1,3,5-triazinen 9 fuhrt die nacheinander erfolgende Umsetzung von 1 mit 2 verschiedenen cyclischen sekundaren Aminen (6 und 8). Die Strukturtypen 3, 5 und 9 zeigen in den 1H-NMR-Spektren zwei fur Piperazinringe charakteristische Signalgruppen im Bereich 2.4–4.0 ppm. Unter den neu entwickelten Verbindungen finden sich Vertreter mit sehr starker antimykotischer W…
Latent measles virus infection in Vero cells depending on a temperature-sensitive phenomenon.
1978
A latent infection by measles virus in a line of Vero cells could be maintained only at 37 degrees C. The conditions of temperature nonpermissiveness were associated with some block in virus production and/or release and with the establishment of an autointerference phenomenon. Reduction of the incubation temperature to 33.5 degrees C induced a rather rapid transition from the latent to a lytical infection with a recue of virus. The rescued virus exhibited a restricted capacity to grow at 37 degrees C.
Synthesis of CO2-responsive polymers by post-polymerization modification
2014
Abstract We describe a general method to synthesize a double responsive polymer, exhibiting a temperature and CO 2 responsive behavior. The polymer derived from a controlled radical polymerization technique of pentafluorophenyl acrylate (PFPA), followed by a sequential post-polymerization modification of a CO 2 responsive- and thermo-responsive amines. Utilizing this approach three double responsive copolymers were synthesized, poly(3- N′,N′ -dimethylaminopropyl acrylamide- co - N -isopropyl acrylamide) (poly(DMPA- co -NIPAM)), poly( L -Arginine methyl ester acrylamide- co - N -isopropyl acrylamide) (poly(AME- co -NIPAM)) and poly( L -Arginine methyl ester acrylamide- co - N -cyclopropyl ac…
Phase transitions in some n-alkanes and petroleum waxes — investigation by photoacoustic and exoelectron emission techniques
2000
Abstract The use of the photoacoustic (PA) effect and photostimulated exoelectron emission (EEE) technique in the investigation of first- and second-order phase transitions in pure n -alkanes such as n -C 22 , n -C 28 and n -C 32 and in three petroleum waxes having different carbon number distributions, have been examined. Changes in the amplitude and phase of the PA signal with temperature and the temperature dependence of the intensity of photostimulated EEE across the phase transitions have been measured. These measurements have shown that both the polymorphic phase transitions and melting of these hydrocarbons are accompanied by jumps or peaks of the PA amplitude and phase and EEE inten…
Temperature-responsive inclusion complex of cationic PNIPAAM diblock copolymer and γ-cyclodextrin
2012
Aqueous mixtures of γ-cyclodextrin (γ-CD) and the thermosensitive cationic diblock copolymer poly(N-isopropylacrylamide)-b-poly(3-acrylamidopropyl)trimethylammonium chloride (PNIPAAM24-b-PAMPTAM(+)9) or the PNIPAAM homopolymer PNIPAAM47 have been investigated using various experimental methods. Solid γ-CD–polymer inclusion complexes (pseudopolyrotaxanes) form at ambient temperatures in fairly concentrated CD solutions. The NMR measurements showed that the stoichiometry of the inclusion complexes is close to two NIPAAM units per CD molecule. The cationic block of the copolymer is not incorporated into the CD cavity. Synchrotron radiation X-ray diffraction spectra of the solid inclusion compl…
Temperature and light sensitive copolymers containing azobenzene moieties prepared via a polymer analogous reaction
2009
Abstract Four different series of polyacrylamides containing different amounts of azobenzene moieties have been synthesized via a polymer analogous reaction of poly(pentafluorophenylacrylate) (PPFPA). All copolymers were designed to exhibit a lower critical solution temperature (LCST) in aqueous solution, which was dependent on (i) the amount of incorporated chromophoric azobenzene groups and (ii) the isomerization state of the respective azobenzene group. Higher LCST values were measured for UV-irradiated solutions of the copolymers in comparison to the non-irradiated copolymer solutions. A maximum difference in the LCST of up to 7 °C was found for the copolymer poly(N,N-dimethylacrylamide…
Morphological transformations in a dually thermoresponsive coil-rod-coil bioconjugate.
2013
We report the conformational and assembly behavior of a thermoresponsive triblock biohybrid conjugate under aqueous conditions. The triblock comprises of poly(diethylene glycol methyl ether methacrylate) (PDEGMEMA) conjugated to the ends of a triple-helix forming collagen-like peptide. The circular dichroism (CD) experiment confirms the ability of the collagen-like peptide middle block to assemble as a triple helix in the hybrid conjugate. Above the LCST (∼35 °C), the collapse of the thermoresponsive PDEGMEMA polymer at the ends of the peptide domain resulted in a concomitant increase in the conformational stability of the peptide domain towards thermal denaturation. Upon cooling back, the …
PNIPAM Copolymers Containing Light-Responsive Chromophores: A Method Toward Molecular Logic Gates
2010
A series of thermo-responsive PNIPAM copolymers containing different amounts of fulgimide moieties has been synthesized via a polymer analogous reaction of poly(pentafluorophenyl acrylate). All copolymers were designed to exhibit a lower critical solution temperature (LCST) in water, which was only weakly dependent on the amount of incorporated chromophoric fulgimide groups. The copolymers showed a photocyclization of the fulgimide side groups upon irradiation with UV-light accompanied with a color change. The closed form of the chromophore had a halftime of 136 min for the visible reisomerization and did not affect the LCST of the polymer. This led to the realization of a logic "NOT A" for…
Temperature- and Light-Responsive Polyacrylamides Prepared by a Double Polymer Analogous Reaction of Activated Ester Polymers
2009
Two different series of polyacrylamides containing different amounts of salicylideneaniline moieties have been synthesized via a double polymer analogous reaction of poly(pentafluorophenyl acrylate) (PPFPA). All copolymers were designed to exhibit a lower critical solution temperature (LCST) in aqueous solution, which was dependent on (i) the amount of incorporated chromophoric salicylideneaniline groups and (ii) the isomerization state of the respective salicylideneaniline group. Higher LCST values were measured for UV-irradiated solutions of the copolymers in comparison to the nonirradiated copolymer solutions. A maximum difference in the LCST of up to 13 °C was found for poly(N-cycloprop…
The effect of pressure on the liquid–liquid phase equilibrium of two polydisperse polyalkylsiloxane blends
2002
The effect of pressure-induced immiscibility in polymer blends is investigated by experimental and theoretical methods. Experimental data of cloud point curves and critical points are obtained by turbidity measurements. The chosen system is a mixture of polydimethylsiloxane and polyhexylmethylsiloxane which is one of the very few polymer blends exhibiting pressure-induced immiscibility. This unusual behaviour is related to a critical temperature minimum of the critical curve and cloud point isopleths at positive pressure in the temperature–pressure diagram. The effect of the chain length on the critical temperature minimum is investigated here based on theoretical models. The effect of diff…