Direct monitoring of photon induced isomerization, dissociation and electron detachment of the green fluorescent protein chromophore anion

We present the first experimental demonstration of Z↔E photoisomerization the GFP chromophore anion, HBDI−, in the gas phase. In the single photon absorption regime, the photoisomerization action spectra show two maxima at 480 nm and 455 nm. In the multiphoton absorption regime, photodissociation and photodetachment channels modify the appearance of the photoisomerization band. This work provides a new approach to characterize photoisomerization pathways in biomolecular ions

Changes in the kinase activity of the insulin receptor account for an increased insulin sensitivity of mammary gland in late pregnancy

Copyright (1998) The Endocrine Society .The paper can be found at the following URL on the website http://endo.endojournals.org

Accretion and photodesorption of CO ice as a function of the incident angle of deposition

Non-thermal desorption of inter- and circum-stellar ice mantles on dust grains, in particular ultraviolet photon-induced desorption, has gained importance in recent years. These processes may account for the observed gas phase abundances of molecules like CO toward cold interstellar clouds. Ice mantle growth results from gas molecules impinging on the dust from all directions and incidence angles. Nevertheless, the effect of the incident angle for deposition on ice photo-desorption rate has not been studied. This work explores the impact on the accretion and photodesorption rates of the incidence angle of CO gas molecules with the cold surface during deposition of a CO ice layer. Infrared spectroscopy monitored CO ice upon deposition at different angles, ultraviolet-irradiation, and subsequent warm-up. Vacuum-ultraviolet spectroscopy and a Ni-mesh measured the emission of the ultraviolet lamp. Molecules ejected from the ice to the gas during irradiation or warm-up were characterized by a quadrupole mass spectrometer. The photodesorption rate of CO ice deposited at 11 K and different incident angles was rather stable between 0 and 45$^{\circ}$. A maximum in the CO photodesorption rate appeared around 70$^{\circ}$-incidence deposition angle. The same deposition angle leads to the maximum surface area of water ice. Although this study of the surface area could not be performed for CO ice, the similar angle dependence in the photodesorption and the ice surface area suggests that they are closely related. Further evidence for a dependence of CO ice morphology on deposition angle is provided by thermal desorption of CO ice experiments

Unlocking room-temperature bistable spin transition at the nanoscale: the synthesis of core@shell [Fe(NH 2 trz) 3 (NO 3 ) 2 ]@SiO 2 nanoparticles †

In this work, we address the synthesis of stable spin-crossover nanoparticles capable of undergoing a hysteretic spin transition at room temperature. For this purpose, we use the reverse-micelle protocol to prepare naked [Fe(NH2trz)3](NO3)2 and core@shell [Fe(NH2trz)3](NO3)2@SiO2 nanoparticles. Through meticulous adjustment of synthetic parameters, we achieved nanoparticle sizes ranging from approximately 40 nm to 60 nm. Our findings highlight that [Fe(NH2trz)3](NO3)2 presents a modest thermal hysteresis of 7 K, which decreases by downsizing. Conversely, silica-coated nanoparticles with sizes of ca. 60 and 40 nm demonstrate a remarkable hysteretic response of approximately 30 K, switching their spin state around room temperature. Moreover, the presence of a SiO2 shell substantially enhances the nanoparticles’ stability against oxidation. In this context, the larger 60 nm [Fe(NH2trz)3](NO3)2@SiO2 hybrid remains stable in water for up to two hours, enabling the observation of an unreported water-induced spin transition after 30 min. Therefore, this work also introduces an intriguing avenue for inducing spin transitions through solvent exchange, underscoring the versatility and potential of these nanoparticles

In Vivo insulin-dependent glucose uptake of specific tissues is decreased during aging of mature wistar rats

Copyright (1997) The Endocrine Society .The paper can be found at the following URL on the website http://endo.endojournals.org