Search results for "absorption"
showing 10 items of 2701 documents
The Photocycle of Bacteriophytochrome Is Initiated by Counterclockwise Chromophore Isomerization.
2022
Photoactivation of bacteriophytochrome involves a cis–trans photoisomerization of a biliverdin chromophore, but neither the precise sequence of events nor the direction of the isomerization is known. Here, we used nonadiabatic molecular dynamics simulations on the photosensory protein dimer to resolve the isomerization mechanism in atomic detail. In our simulations the photoisomerization of the D ring occurs in the counterclockwise direction. On a subpicosecond time scale, the photoexcited chromophore adopts a short-lived intermediate with a highly twisted configuration stabilized by an extended hydrogen-bonding network. Within tens of picoseconds, these hydrogen bonds break, allowing the c…
Local Structure Studies of Ti for SrTi16O3 and SrTi18O3 by Advanced X-ray Absorption Spectroscopy Data Analysis
2015
Strontium titanate is a model quantum paraelectric in which in the region of dominating quantum statistics the ferroelectric instability is inhibited due to nearly complete compensation of the harmonic contribution into ferroelectric soft mode frequency by the zero-point motion contribution. The enhancement of atomic masses by the substitution of 18O for 16O decreases the zero-point atomic motion and low-T ferroelectricity in SrTi18O3 is realized. In this study we report on the local structure of Ti in SrTi16O3 and SrTi18O3 by Ti K-edge extended x-ray absorption fine structure measurements in temperature range 6 – 300 K.
Micro evidence for sources of innovation in European countries
2012
This paper investigates sources of product or process innovation, such as investments in research and development, machinery, personnel training and management systems, by examining microdata from eight European countries. We pay particular attention to the effect of research and development in favouring the absorption of new technologies, i.e. the absorptive capacity. Significant positive effects of each source on both product and process innovations are found. Significant evidence of positive absorptive capacity emerges only in firms with low predicted probabilities of introducing innovation.
Pt(II) and Pd(II)-assisted coupling of nitriles and 1,3-diiminoisoindoline : Synthesis and luminescence properties of (1,3,5,7,9-pentaazanona-1,3,6,8…
2017
Treatment of trans-[PtCl2(NCR)2] 1 (R = Me (1a), Et (1b), o-ClC6H4 (1c), p-ClC6H4 (1d), p-(HCdouble bond; length as m-dashO)C6H4 (1e), p-O2NC6H4CH2 (1f)) with 1,3-diiminoisoindoline HNdouble bond; length as m-dashCC6H4C(NH)double bond; length as m-dashNH 2 gives access to the corresponding (1,3,5,7,9-pentaazanona-1,3,6,8-tetraenato)Pt(II) complexes [PtCl{NHdouble bond; length as m-dashC(R)Ndouble bond; length as m-dashC(C6H4)NCdouble bond; length as m-dashNC(R)double bond; length as m-dashNH}] 3a–f, in good yields (65–70%). The reaction of trans-[PdCl2(NCMe)2] 4a with 2 furnishes (1,3,5,7,9-pentaazanona-1,3,6,8-tetraenato)Pd(II) complex [PdCl{NHdouble bond; length as m-dashC(Me)Ndouble bond…
Fast Photochemistry of Prototypical Phytochromes : A Species vs. Subunit Specific Comparison
2015
Phytochromes are multi-domain red light photosensor proteins, which convert red light photons to biological activity utilizing the multitude of structural and chemical reactions. The steady increase in structural information obtained from various bacteriophytochromes has increased understanding about the functional mechanism of the photochemical processes of the phytochromes. Furthermore, a number of spectroscopic studies have revealed kinetic information about the light-induced reactions. The spectroscopic changes are, however, challenging to connect with the structural changes of the chromophore and the protein environment, as the excited state properties of the chromophores are very sens…
All-Organic Waveguide Sensor for Volatile Solvent Sensing
2019
This work was supported by ERDF 1.1.1.1 Activity Project Nr. 1.1.1.1/16/A/046 “Application assessment of novel organic materials by prototyping of photonic devices”. We acknowledge Igors MIHAILOVS for valuable discussions.
Time of flight for photon in human skin
2016
The time of flight for photons in human skin was measured using picosecond diode laser. Two different wavelength lasers were used - 405 nm and 510 nm. A difference for time of flight in normal skin and in nevus was observed as well as a difference for different wavelength laser irradiation was observed. For 405 nm laser irradiation the difference was 41 ps while comparison of time of flights skin and nevi using 510 nm irradiation showed a result of 32 ps. Results allow to conclude that the time photon travels in skin might depend on the characteristics of the medium and wavelength of the irradiation. This can be related to known data for light penetration depth in human skin for different w…
Comparison of a near-infrared reflectance spectroscopy system and skin conductance measurements for in vivo estimation of skin hydration: a clinical …
2017
Diffuse reflectance spectroscopy system was developed for estimation of skin hydration in the near-infrared spectral range of 900-1700 nm. Experimental setup consisted of a near-infrared spectrometer, Y-type fiber optics probe with 1 detection and 6 illumination fibers, halogen-tungsten light source and a PC. By analyzing diffuse reflectance spectrum, a parameter representing skin hydration by performing baseline correction and calculating the area under the 1450 nm water absorption maximum is proposed. A clinical study was performed acquiring data of skin hydration of 39 patients' forearm skin. Results of the developed system are compared to results obtained by a commercial device based on…
Role of Nutraceuticals in Hypolipidemic Therapy.
2015
Nutraceuticals are food components or active ingredients present in foods and used in therapy. This article analyzes the characteristics of the molecules with a lipid-lowering effect. The different nutraceuticals may have different mechanisms of action: inhibition of cholesterol synthesis primarily through action on the enzyme HMG-CoA reductase (policosanol, polyphenols, garlic and, above all, red yeast rice), increase in LDL receptor activity (berberine), reduction of intestinal cholesterol absorption (garlic, plant sterols, probiotics), and also the ability to interfere with bile metabolism (probiotics, guggul). Based on the different mechanisms of action, some nutraceuticals are then abl…
7 YEARS OF EUROPEAN FUNDING IN ROMANIA - BETWEEN SUCCESS AND FAILURE
2015
This paper aims to achieve an overall picture of the absorption rate of European funds in Romania for the 2007-2013 programming period and to propose a series of recommendations on the steps our country needs to follow in order to improve the process of accessing and implementation of structural instruments at national level. These recommendations focus on preventing obtaining a low rate of absorption of EU funds allocated to Romania in the multiannual financial framework 2014-2020 , thus preventing wastage prospects of economic and social modernization , that these funds offer.