Search results for "MERIS"
showing 10 items of 924 documents
Study of the accretion torque during the 2014 outburst of the X-ray pulsar GRO J1744−28
2017
We present the spectral and timing analysis of the X-ray pulsar GRO J1744-28 during its 2014 outburst using data collected with the X-ray satellites Swift, INTEGRAL, Chandra, and XMM-Newton. We derived, by phase-connected timing analysis of the observed pulses, an updated set of the source ephemeris. We were also able to investigate the spin-up of the X-ray pulsar as a consequence of the accretion torque during the outburst. Relating the spin-up rate and the mass accretion rate as $\dot{\nu}\propto\dot{M}^{\beta}$, we fitted the pulse phase delays obtaining a value of $\beta=0.96(3)$. Combining the results from the source spin-up frequency derivative and the flux estimation, we constrained …
Enantiodifferentiation of N-benzyloxycarbonylaminophosphonic and phosphinic acids and their esters using cyclodextrins by means of capillary electrop…
2005
Capillary electrophoresis was successfully applied for separation of the enantiomers of N-benzyloxycarbonyl-alpha-aminophosphonic and alpha-aminophosphinic acids as well as their ethyl and phenyl monoesters with the use of a range of commercially available cyclodextrins (alpha, beta and hydroxypropyl-gamma-cyclodextrins) as chiral selectors. The dependence of effectiveness of separation on type and concentration of these chiral selectors as well as on pH of background electrolyte was examined in some detail.
Separation of aminoalkanephosphonic acid enantiomers by indirect UV detection capillary electrophoresis with application of cyclodextrins.
2003
Indirect UV detection capillary electrophoresis (CE) was used for the separation of aminoalkanephosphonic acid (AP) enantiomers by applying commercially available cyclodextrins as chiral discriminators. The results show that the separation of the enantiomers depends on pH of the background electrolyte, the molar ratio of cyclodextrin to aminophosphonic acid, and on the type of the applied chiral selector. Optimization of process conditions allowed enantiomeric baseline separation or partial separation of 12 out of 14 alpha-aminophosphonic acids studied. This type of CE might therefore be successfully used for routine determination of enantiomeric purity of aminophosphonic acids.
Resinas compuestas: Revisión de los materiales e indicaciones clínicas
2006
El objetivo de este trabajo es presentar los diferentes componentes de los composites actualmente utilizados en Odontología y aportar al profesional las bases que puedan proporcionarle los criterios a tener en cuenta para seleccionar uno u otro en función de los requerimientos terapéuticos. La mayoría de los composites de uso en Odontología corresponden a materiales híbridos, se denominan así por estar conformados por grupos poliméricos reforzados por una fase inorgánica de vidrio de diferente composición, tamaño y porcentaje de relleno. Los composites fluidos o los condensables han tratado de dar respuesta algunos requerimientos funcionales, aunque sin demasiado éxito en la mejora de sus p…
Towards low-energy-light-driven bistable photoswitches : ortho-fluoroaminoazobenzenes
2021
AbstractThermally stable photoswitches that are driven with low-energy light are rare, yet crucial for extending the applicability of photoresponsive molecules and materials towards, e.g., living systems. Combined ortho-fluorination and -amination couples high visible light absorptivity of o-aminoazobenzenes with the extraordinary bistability of o-fluoroazobenzenes. Herein, we report a library of easily accessible o-aminofluoroazobenzenes and establish structure–property relationships regarding spectral qualities, visible light isomerization efficiency and thermal stability of the cis-isomer with respect to the degree of o-substitution and choice of amino substituent. We rationalize the exp…
Asymmetric Organocatalytic Wittig [2,3]-Rearrangement of Oxindoles
2016
A highly enantioselective organocatalytic [2,3]-rearrangement of oxindole derivatives is presented. The reaction was catalyzed by squaramide, and this provides access to 3-hydroxy 3-substituted oxindoles in high enantiomeric purities.
Aksjologiczne aspekty wychowania
2016
Artykuł ukazuje problematykę dotyczącą aksjologicznego aspektu wychowania,jest poszukiwaniem odpowiedzi na pytanie: Jak wychowywać młodego człowieka, by potrafił poruszać się w przestrzeni aksjologicznej, umiał odkrywać, tworzyć, akceptować wartości w poszukiwaniu swojego miejsca w świecie? Uważam, że aby wychować młodego człowieka, tak by żył zgodnie z wartościami uniwersalnymi, należy zadbać o to, by potrafił uczyć się obiektywnego poznawania i respektowania wartości, rozbudzał w sobie zainteresowanie życiem wartościowym. W artykule podkreślono, że aksjologiczny wymiar aktywności człowieka ulega przekierunkowaniu na wartości niższe (hedonistyczne, utylitarne, witalne, prestiżowe). Słabnie…
Preorganization and reorganization as related factors in enzyme catalysis: the chorismate mutase case.
2003
In this paper a deeper insight into the chorismate-to prephenate-rearrangement, catalyzed by Bacillus subtilis chorismate mutase, is provided by means of a combination of statistical quantum mechanics/molecular mechanics simulation methods and hybrid potential energy surface exploration techniques. The main aim of this work is to present an estimation of the preorganization and reorganization terms of the enzyme catalytic rate enhancement. To analyze the first of these, we have studied different conformational equilibria of chorismate in aqueous solution and in the enzyme active site. Our conclusion is that chorismate mutase preferentially binds the reactive conformer of the substrate--that…
Strongavidiini - biotiinia sitova merisiilestä peräisin oleva avidiinin kaltainen proteiini
2009
Biotiinia eli vitamiinia H suurimmalla luonnossa tavatulla ei-kovalenttisella affiniteetilla sitovaa avidiinia ja sen bakteeriperäistä sukulaisproteiinia streptavidiini käytetään laajasti erilaisissa avidiini-biotiini teknologian sovellutuksissa. Alun perin avidiini löydettiin kananmunan valkuaisesta ja sen rakenne on myöhemmin selvitetty tarkasti. Avidiinilla ja streptavidiinilla on monia hyödyllisiä ominaisuuksia. Avidiinin ja streptavidiinin on havaittu biotiiniin sitouduttuaan olevan erittäin stabiileja proteiineja, jotka kestävät hyvin mm. proteolyyttisiä entsyymejä ja ne omaavat voimakkaan lämmönkestävyyden. Yksi avidiini koostuu neljästä samanlaisesta monomeeristä, joista jokainen py…
Bis-urea macrocycles with a deep cavity.
2015
Two configurational isomers of bis-urea macrocycles have been synthesized, and their neutral molecule recognition was studied by X-ray crystallography and (1)H NMR experiments. Cooperative action between the deep cavity and the urea groups and the influence of dipole alignments on molecular recognition are discussed.