Search results for "OMOP"

Tracking Changes in Protonation and Conformation during Photoactivation of a Phytochrome Protein

2016

Phytochromes are photosensor proteins in plants and bacteria. The biological response is mediated by structural changes that follow photon absorption in the protein complex. The initial step is the photoisomerization of the biliverdin chromophore. How this leads to large-scale structural changes of the whole complex is, however, poorly understood. In this work, we use molecular dynamics (MD) simulations to investigate the structural changes after isomerization. In particular, we perform MD simulations at constant pH, using a recently developed method, to explore the effect of chromophore isomerization on the protonation (pKa) of nearby residues. In addition, we use a hybrid quantum mechanic…

A Curcumin-BODIPY Dyad and Its Silica Hybrid as NIR Bioimaging Probes

2022

In this paper we describe the synthesis of a novel bichromophoric system in which an efficient photoinduced intercomponent energy transfer process is active. The dyad consists of one subunit of curcumin and one of BODIPY and is able to emit in the far-red region, offering a large Stokes shift, capable of limiting light scattering processes for applications in microscopy. The system has been encapsulated in MCM-41 nanoparticles with dimensions between 50 and 80 nm. Both the molecular dyad and individual subunits were tested with different cell lines to study their effective applicability in bioimaging. MCM-41 nanoparticles showed no reduction in cell viability, indicating their biocompatibil…

Contributo alla conoscenza dei crostacei branchiopodi della RNO "Saline di Trapani e Paceco": stato delle conoscenze

2004

Electronic and Functional Scope of Boronic Acid Derived Salicylidenehydrazone (BASHY) Complexes as Fluorescent Dyes

2017

[EN] A series of boronic acid derived salicylidenehydrazone (BASHY) complexes was prepared and photophysically characterized. The dye platform can be modified by (a) electronic tuning along the cyanine-type axis via modification of the donor-acceptor pair and (b) functional tuning via the boronic acid residue. On the one hand, approach (a) allows the control of photophysical parameters such as Stokes shift, emission color, and two-photon absorption (2PA) cross section. The resulting dyes show emission light-up behavior in nonpolar media and are characterized by high fluorescence quantum yields (ca. 0.5-0.7) and brightness (ca. 35000-40000 M-1 cm(-1)). Moreover, the 2PA cross sections reach …

Systematic study of SYBR green chromophore reveals major improvement with one heteroatom difference

2021

Five nucleic acid binding cyanine dyes were synthesized and their photophysical properties were evaluated. Changing a single heteroatom in the chromophore causes major differences both in brightness and photostability between the dyes. With such alteration, the brightness of the chromophore increased two-fold compared to the one found in SYBR Green I.

Theoretical study of the low‐lying states of trans‐1,3‐butadiene

1992

We present extensive ab initio calculations on the low‐lying electronic states of trans‐1,3‐butadiene within the multireference configuration interaction (MRCI) framework by selecting the configurations with a perturbative criterion. The X 1Ag ground state and 1 3Bu, 1 3Ag, 2 1Ag, and 1 1Bu valence excited states have been calculated at a fixed geometry. The results obtained are in good agreement with previous experimental and calculated values, and could help to understand polyene spectroscopy, photochemistry, and photophysics. The advantages of a MRCI method where the most important contributions to the total MRCI wave function, perturbatively selected, are treated variationally, and the …

Low frequency of HLA haplotype loss associated with loss of heterozygocity in chromosome region 6p21 in clear renal cell carcinomas.

2004

HLA class I loss or downregulation is a widespread mechanism used by tumor cells to avoid tumor recognition by cytotoxic T lymphocytes favoring tumor immune escape. Multiple molecular mechanisms are responsible for these altered HLA class I tumor phenotypes. It has been described in different epithelial tumors that loss of heterozygosity (LOH) at chromosome region 6p21.3 is a frequent mechanism that leads to HLA haplotype loss, ranging between 40 and 50%, depending on the tumor entity analyzed. Here we have tested the frequency of LOH at 6p21 chromosome region in Renal Cell Carcinomas (RCC) of the clear cell and chromophobe subtype. A low frequency of HLA haplotype loss (6.6%) was found in …

THE FRESHWATER CLADOCERA (ORDERS CTENOPODA AND ANOMOPODA) OF MEXICO, WITH COMMENTS ON SELECTED TAXA

1999

AbstractKnowledge of the composition and distribution of the freshwater Cladocera in Mexico is still limited. All the available literature was reviewed and added to our own new records in different states of Mexico to present here a revised and updated list of the 110 species of the orders Ctenopoda and Anomopoda recorded for the country, with separate state records. Ecological, biogeographical, and taxonomic comments are made for selected taxa of the commonest neotropical groups: Sididae, Daphniidae, Bosminidae, Macrothricidae, and Chydoridae. La connaissance de la composition et de la repartition des Cladoceres d'eau douce du Mexique est encore tres limitee. Toute la litterature disponibl…

Damming an electronic energy reservoir: ion-regulated electronic energy shuttling in a [2]rotaxane

2021

We demonstrate the first example of bidirectional reversible electronic energy transfer (REET) between the mechanically bonded components of a rotaxane. Our prototypical system was designed such that photoexcitation of a chromophore in the axle results in temporary storage of electronic energy in a quasi-isoenergetic “reservoir” chromophore in the macrocycle. Over time, the emissive state of the axle is repopulated from this reservoir, resulting in long-lived, delayed luminescence. Importantly, we show that cation binding in the cavity formed by the mechanical bond perturbs the axle chromophore energy levels, modulating the REET process, and ultimately providing a luminescence read-out of c…

Synthesis, spectroscopic studies and biological evaluation of acridine derivatives: The role of aggregation on the photodynamic efficiency.

2018

Two new photoactive compounds (1 and 2) derived from the 9-amidoacridine chromophore have been synthesized and fully characterized. Their abilities to produce singlet oxygen upon irradiation have been compared. The synthesized compounds show very different self-aggregating properties since only 1 present a strong tendency to aggregate in water. Biological assays were conducted with two cell types: hepatoma cells (Hep3B) and human umbilical vein endothelial cells (HUVEC). Photodynamic therapy (PDT) studies carried out with Hep3B cells showed that non-aggregating compound 2 showed photoxicity, ascribed to the production of singlet oxygen, being aggregating compound 1 photochemically inactive.…