Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 86
Filtrar
Más filtros

Banco de datos
Tipo del documento
Intervalo de año de publicación
1.
Int J Mol Sci ; 25(6)2024 Mar 13.
Artículo en Inglés | MEDLINE | ID: mdl-38542218

RESUMEN

This study addresses the pressing issues of energy production and consumption, in line with global sustainable development goals. Focusing on the potential of alcohols as "green" alternatives to traditional fossil fuels, especially in biofuel applications, we investigate the thermochemical properties of three alcohols (n-propanol, n-butanol, n-pentanol) blended with sunflower oil. The calorimetric analysis allows for the experimental determination of excess enthalpies in pseudo-binary mixtures at 303.15 K, revealing similarities in the trends of the curves (dependence on concentrations) but with different values for the excess enthalpies for each mixture. Despite the structural differences of the alcohols studied, the molar excess enthalpy values exhibit uniformity, suggesting consistent mixing behavior. The peak values of excess enthalpies for systems with sunflower oil and n-propanol, n-butanol and n-pentanol are, respectively, 3255.2 J/mole, 3297.4 J/mole and 3150.1 J/mole. Both the NRTL and Redlich-Kister equations show satisfactory agreement with the obtained values.


Asunto(s)
Alcoholes , Biocombustibles , Pentanoles , Alcoholes/química , Aceite de Girasol , 1-Propanol , 1-Butanol
2.
Int J Mol Sci ; 25(5)2024 Mar 06.
Artículo en Inglés | MEDLINE | ID: mdl-38474299

RESUMEN

NanoFAST is the smallest fluorogen-activating protein, consisting of only 98 amino acids, used as a genetically encoded fluorescent tag. Previously, only a single fluorogen with an orange color was revealed for this protein. In the present paper, using rational mutagenesis and in vitro screening of fluorogens libraries, we expanded the color palette of this tag. We discovered that E46Q is one of the key substitutions enabling the range of possible fluorogens to be expanded. The introduction of this and several other substitutions has made it possible to use not only orange but also red and green fluorogens with the modified protein.


Asunto(s)
Colorantes Fluorescentes , Proteínas , Colorantes Fluorescentes/química
3.
Entropy (Basel) ; 26(6)2024 May 22.
Artículo en Inglés | MEDLINE | ID: mdl-38920446

RESUMEN

Quantum cryptography revolutionizes secure information transfer, providing defense against both quantum and classical computational attacks. The primary challenge in extending the reach of quantum communication comes from the exponential decay of signals over long distances. We meet this challenge by experimentally realizing the Quantum-Protected Control-Based Key Distribution (QCKD) protocol, utilizing physical control over signal losses. By ensuring significant non-orthogonality of the leaked quantum states, this control severely constrains eavesdroppers' capacities. We demonstrate the performance and scale of our protocol by experiments over a 1707 km long fiber line. The scalability of the QCKD opens the route for globally secure quantum-resistant communication.

4.
Org Biomol Chem ; 21(45): 9082-9085, 2023 Nov 22.
Artículo en Inglés | MEDLINE | ID: mdl-37942901

RESUMEN

2-Allyloxybenzaldehydes undergo [2 + 1] cycloadditions under 365 nm LED irradiation to form the corresponding chroman-fused cyclopropanols. The reaction proceeds easily without any catalysts or additives in dimethyl sulfoxide.

5.
J Chem Phys ; 159(16)2023 Oct 28.
Artículo en Inglés | MEDLINE | ID: mdl-37877487

RESUMEN

Accurate description of electronic excited states of high-spin molecular species is a yet unsolved problem in modern electronic structure theory. A composite computational scheme developed in the present work contributes to solving this task for a challenging case of lanthanide-containing molecules. In the scheme, the highest-spin states whose wavefunctions are dominated by a single Slater determinant are described at the single-reference (SR) CCSD(T) level, whereas the lower-spin states, being inherently multiconfigurational in their nature, are treated with multireference (MR) methods, MRCI and/or CASPT2. An original technique which scales MR results against SR CCSD(T) ones to improve the accuracy in the former is proposed and examined, taking the example of 12 electronic states of gadolinium monoxide, X9Σ-, Y7Σ-, A'9Δ, A1'7Δ, A9Π, A17Π, B9Σ-, B17Σ-, C9Π, C17Π, D9Σ-, and D17Σ-, up to 35 000 cm-1. A multitude of the corresponding Ω (spin-coupled) states was then studied within the state-interacting approach employing the full Breit-Pauli spin-orbit coupling operator with CASSCF-generated ΛS states as a basis. For all ΛS and Ω states, the Gd-O bond lengths, spectroscopic constants ωe, ωexe, αe, and adiabatic excitation energies are obtained. The theoretical predictions are in good agreement with the experimental data, with deviations in excitation energies not exceeding 350 cm-1 (1 kcal/mol). The spectroscopic properties of the yet unobserved electronic states, A'9Δ, A1'7Δ, C9Π, C17Π, D9Σ-, and D17Σ-, are evaluated for the first time.

6.
An Acad Bras Cienc ; 95(suppl 3): e20210816, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37937655

RESUMEN

Aerosols have implications to climate and biogeochemical cycles in the global oceans. At sites under indirect influence of dust emitted by the Patagonian semi-desert, a debate exists on the potential fertilization effects of iron enriched aerossol. Considering this subject we conducted measurements of aerosols optical properties using a Microtops II sun photometer to access aerosol size distributions and other intrinsic properties oversea from Atlantic Southern mid-latitudes to Antarctica. Oceanographic cruises were developed between December 2010 to April 2011 and October 2011 to April 2012, in the context of the Brazilian Antarctic Program, and between November 2011 to December 2011. This survey was taken as part of the Global Maritime Aerosol Network (MAN/NASA). Our data of AOD (500 nm) along the South American coast depicts a steady decrease southwards following the decreased latitudinal continental extent. However, the influence of the aerosols blown from Patagonia semi-desert region was clear from latitude 53°S to 64°S. The predominance of aerosol fine mode was observed in Central Atlantic and close to the Drake Passage. An unexpected aerosol coarse mode predominance was found close to the Antarctic Peninsula. We attribute that to a possible weathering of rock outcrops due to the strong westerly winds in that region.


Asunto(s)
Contaminantes Atmosféricos , Monitoreo del Ambiente , Humanos , Estaciones del Año , Clima , Tiempo (Meteorología) , Aerosoles/análisis , Contaminantes Atmosféricos/análisis
7.
Sensors (Basel) ; 23(14)2023 Jul 14.
Artículo en Inglés | MEDLINE | ID: mdl-37514684

RESUMEN

We have shown the opportunity to use the unique inhomogeneities of the internal structure of an optical fiber waveguide for remote authentication of users or an optic fiber line. Optical time domain reflectometry (OTDR) is demonstrated to be applicable to observing unclonable backscattered signal patterns at distances of tens of kilometers. The physical nature of the detected patterns was explained, and their characteristic spatial periods were investigated. The patterns are due to the refractive index fluctuations of a standard telecommunication fiber. We have experimentally verified that the patterns are an example of a physically unclonable function (PUF). The uniqueness and reproducibility of the patterns have been demonstrated and an outline of authentication protocol has been proposed.

8.
Int J Mol Sci ; 24(5)2023 Mar 06.
Artículo en Inglés | MEDLINE | ID: mdl-36902449

RESUMEN

Structural maintenance of chromosomes (SMC) complexes are essential proteins found in genomes of all cellular organisms. Essential functions of these proteins, such as mitotic chromosome formation and sister chromatid cohesion, were discovered a long time ago. Recent advances in chromatin biology showed that SMC proteins are involved in many other genomic processes, acting as active motors extruding DNA, which leads to the formation of chromatin loops. Some loops formed by SMC proteins are highly cell type and developmental stage specific, such as SMC-mediated DNA loops required for VDJ recombination in B-cell progenitors, or dosage compensation in Caenorhabditis elegans and X-chromosome inactivation in mice. In this review, we focus on the extrusion-based mechanisms that are common for multiple cell types and species. We will first describe an anatomy of SMC complexes and their accessory proteins. Next, we provide biochemical details of the extrusion process. We follow this by the sections describing the role of SMC complexes in gene regulation, DNA repair, and chromatin topology.


Asunto(s)
Proteínas de Ciclo Celular , Proteínas Cromosómicas no Histona , Animales , Ratones , Proteínas Cromosómicas no Histona/metabolismo , Proteínas de Ciclo Celular/metabolismo , Cromatina , ADN/química , Caenorhabditis elegans/metabolismo
9.
Int J Mol Sci ; 24(9)2023 Apr 27.
Artículo en Inglés | MEDLINE | ID: mdl-37175667

RESUMEN

In this work, we showed that the well-known NanoLuc luciferase can act as a fluorogen activating protein for various arylidene-imidazolones structurally similar to the Kaede protein chromophore. We showed that such compounds can be used as fluorescent sensors for this protein and can also be used in pairs with it in fluorescent microscopy as a genetically encoded tag.


Asunto(s)
Colorantes Fluorescentes , Colorantes Fluorescentes/metabolismo , Luciferasas/genética , Microscopía Fluorescente
10.
Int J Mol Sci ; 24(12)2023 Jun 08.
Artículo en Inglés | MEDLINE | ID: mdl-37373071

RESUMEN

In this work, we have shown that the introduction of a trifluoromethyl group into the me-ta-position of arylidene imidazolones (GFP chromophore core) leads to a dramatic increase in their fluorescence in nonpolar and aprotic media. The presence of a pronounced solvent-dependent gradation of fluorescence intensity makes it possible to use these substances as fluorescent polarity sensors. In particular, we showed that one of the created compounds could be used for selective labeling of the endoplasmic reticulum of living cells.


Asunto(s)
Colorantes , Proteínas Fluorescentes Verdes , Solventes , Espectrometría de Fluorescencia
11.
Phys Rev Lett ; 128(21): 212002, 2022 May 27.
Artículo en Inglés | MEDLINE | ID: mdl-35687465

RESUMEN

We compute the photon-quark and Higgs-gluon form factors to four-loop order within massless perturbative quantum chromodynamics. Our results constitute ready-to-use building blocks for N^{4}LO cross sections for Drell-Yan processes and gluon-fusion Higgs boson production at the LHC. We present complete analytic expressions for both form factors and show several of the most complicated master integrals.

12.
Phys Rev Lett ; 128(18): 187202, 2022 May 06.
Artículo en Inglés | MEDLINE | ID: mdl-35594098

RESUMEN

We report experimental verification of the recently predicted collective modes of spinons, stabilized by backscattering interaction, in a model quantum spin chain material. We exploit the unique geometry of uniform Dzyaloshinskii-Moriya interactions in K_{2}CuSO_{4}Br_{2} to measure the interaction-induced splitting between the two components of the electron spin resonance (ESR) response doublet. From that we directly determine the magnitude of the "marginally irrelevant" backscattering interaction between spinons for the first time.

13.
Transgenic Res ; 31(4-5): 525-535, 2022 10.
Artículo en Inglés | MEDLINE | ID: mdl-35960480

RESUMEN

In this work, we set out to create mice susceptible to the SARS-CoV-2 coronavirus. To ensure the ubiquitous expression of the human ACE2 gene we used the human EF1a promoter. Using pronuclear microinjection of the transgene construct, we obtained six founders with the insertion of the EF1a-hACE2 transgene, from which four independent mouse lines were established. Unfortunately, only one line had low levels of hACE2 expression in some organs. In addition, we did not detect the hACE2 protein in primary lung fibroblasts from any of the transgenic lines. Bisulfite sequencing analysis revealed that the EF1a promoter was hypermethylated in the genomes of transgenic animals. Extensive analysis of published works about transgenic animals indicated that EF1a transgenic constructs are frequently inactive. Thus, our case cautions against using the EF1a promoter to generate transgenic animals, as it is prone to epigenetic silencing.


Asunto(s)
Enzima Convertidora de Angiotensina 2 , Ratones Transgénicos , Enzima Convertidora de Angiotensina 2/genética , Animales , COVID-19 , Modelos Animales de Enfermedad , Humanos , Ratones , Factor 1 de Elongación Peptídica/genética , Regiones Promotoras Genéticas , SARS-CoV-2/genética , Transgenes
14.
Nucleic Acids Res ; 48(2): 719-735, 2020 01 24.
Artículo en Inglés | MEDLINE | ID: mdl-31740957

RESUMEN

Mechanisms that ensure repair of double-strand DNA breaks (DSBs) are instrumental in the integration of foreign DNA into the genome of transgenic organisms. After pronuclear microinjection, exogenous DNA is usually found as a concatemer comprising multiple co-integrated transgene copies. Here, we investigated the contribution of various DSB repair pathways to the concatemer formation. We injected mouse zygotes with a pool of linear DNA molecules carrying unique barcodes at both ends and obtained 10 transgenic embryos with 1-300 transgene copies. Sequencing the barcodes allowed us to assign relative positions to the copies in concatemers and detect recombination events that occurred during integration. Cumulative analysis of approximately 1,000 integrated copies reveals that over 80% of them underwent recombination when their linear ends were processed by synthesis-dependent strand annealing (SDSA) or double-strand break repair (DSBR). We also observed evidence of double Holliday junction (dHJ) formation and crossing over during the concatemer formations. Sequencing indels at the junctions between copies shows that at least 10% of DNA molecules introduced into the zygotes are ligated by non-homologous end joining (NHEJ). Our barcoding approach, verified with Pacific Biosciences Single Molecule Real-Time (SMRT) long-range sequencing, documents high activity of homologous recombination after DNA microinjection.


Asunto(s)
Roturas del ADN de Doble Cadena , ADN/química , Recombinación Homóloga/genética , Transgenes/genética , Animales , Animales Modificados Genéticamente , ADN/genética , Código de Barras del ADN Taxonómico , Reparación del ADN por Unión de Extremidades/genética , Reparación del ADN/genética , ADN Cruciforme/química , ADN Cruciforme/genética , Ratones , Cigoto/crecimiento & desarrollo
15.
Molecules ; 27(16)2022 Aug 18.
Artículo en Inglés | MEDLINE | ID: mdl-36014513

RESUMEN

A new simple one-pot two-step protocol for the synthesis of 2-oxo-1,2,3,4-tetrahydroquinoline-3-carboxylate from 2-(2-(benzylamino)benzylidene)malonate under the action of BF3·Et2O was developed. It was shown that the reaction proceeds through the formation of a stable iminium intermediate containing a difluoroboryl bridge in the dicarbonyl fragment of the molecule.


Asunto(s)
Quinolinas , Ácidos Carboxílicos , Ciclización
16.
Chemistry ; 27(12): 3986-3990, 2021 Feb 24.
Artículo en Inglés | MEDLINE | ID: mdl-33336838

RESUMEN

Using benzylidene imidazolone core, we created a panel of color-shifted fluorogenic ligands for FAST protein without compromise to the binding efficiency and the utility for live-cell protein labeling. This study highlights the potential of benzylidene imidazolones derivatives for rapid expansion of a pallet of live-cell fluorogenic labeling tools.


Asunto(s)
Colorantes Fluorescentes , Proteínas
17.
Molecules ; 26(12)2021 Jun 18.
Artículo en Inglés | MEDLINE | ID: mdl-34207029

RESUMEN

The application of micro-Raman spectroscopy was used for characterization of structural features of the high-k stack (h-k) layer of "silicon-on-insulator" (SOI) nanowire (NW) chip (h-k-SOI-NW chip), including Al2O3 and HfO2 in various combinations after heat treatment from 425 to 1000 °C. After that, the NW structures h-k-SOI-NW chip was created using gas plasma etching optical lithography. The stability of the signals from the monocrine phase of HfO2 was shown. Significant differences were found in the elastic stresses of the silicon layers for very thick (>200 nm) Al2O3 layers. In the UV spectra of SOI layers of a silicon substrate with HfO2, shoulders in the Raman spectrum were observed at 480-490 cm-1 of single-phonon scattering. The h-k-SOI-NW chip created in this way has been used for the detection of DNA-oligonucleotide sequences (oDNA), that became a synthetic analog of circular RNA-circ-SHKBP1 associated with the development of glioma at a concentration of 1.1 × 10-16 M. The possibility of using such h-k-SOI NW chips for the detection of circ-SHKBP1 in blood plasma of patients diagnosed with neoplasm of uncertain nature of the brain and central nervous system was shown.


Asunto(s)
Glioma/genética , Nanocables/química , ARN Circular/química , ARN Circular/genética , Silicio/química , Anciano , Técnicas Biosensibles/métodos , Encéfalo/efectos de los fármacos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Análisis de Secuencia por Matrices de Oligonucleótidos/métodos , Espectrometría Raman/métodos
18.
EMBO J ; 35(23): 2584-2601, 2016 12 01.
Artículo en Inglés | MEDLINE | ID: mdl-27797818

RESUMEN

Homologous recombination (HR) is a key pathway that repairs DNA double-strand breaks (DSBs) and helps to restart stalled or collapsed replication forks. How HR supports replication upon genotoxic stress is not understood. Using in vivo and in vitro approaches, we show that the MMS22L-TONSL heterodimer localizes to replication forks under unperturbed conditions and its recruitment is increased during replication stress in human cells. MMS22L-TONSL associates with replication protein A (RPA)-coated ssDNA, and the MMS22L subunit directly interacts with the strand exchange protein RAD51. MMS22L is required for proper RAD51 assembly at DNA damage sites in vivo, and HR-mediated repair of stalled forks is abrogated in cells expressing a MMS22L mutant deficient in RAD51 interaction. Similar to the recombination mediator BRCA2, recombinant MMS22L-TONSL limits the assembly of RAD51 on dsDNA, which stimulates RAD51-ssDNA nucleoprotein filament formation and RAD51-dependent strand exchange activity in vitro Thus, by specifically regulating RAD51 activity at uncoupled replication forks, MMS22L-TONSL stabilizes perturbed replication forks by promoting replication fork reversal and stimulating their HR-mediated restart in vivo.


Asunto(s)
Proteínas de Unión al ADN/metabolismo , FN-kappa B/metabolismo , Proteínas Nucleares/metabolismo , Recombinasa Rad51/metabolismo , Recombinación Genética , Daño del ADN , Reparación del ADN , Replicación del ADN , Células HeLa , Humanos , Mapeo de Interacción de Proteínas , Multimerización de Proteína
19.
Appl Opt ; 59(27): 8443-8449, 2020 Sep 20.
Artículo en Inglés | MEDLINE | ID: mdl-32976430

RESUMEN

Diffraction optical elements (DOE) are important elements of systems for images displaying and processing. The DOE materials with both positive and negative birefringence enhance performances and functionality of such systems. We have calculated the diffraction of rays passing through optically anisotropic grating with surface microrelief by using our original Exedeep software. At the first time the diffraction parameters for both transmitted and reflected TE- and TM-waves are calculated for materials with both positive and negative optical anisotropy. The simulation results are to be used to create DOE for the visible, UV, IR and THz ranges.

20.
Chemistry ; 25(41): 9592-9596, 2019 Jul 22.
Artículo en Inglés | MEDLINE | ID: mdl-31111975

RESUMEN

A genetically encoded fluorescent tag for live cell microscopy is presented. This tag is composed of previously published fluorogen-activating protein FAST and a novel fluorogenic derivative of green fluorescent protein (GFP)-like chromophore with red fluorescence. The reversible binding of the novel fluorogen and FAST is accompanied by three orders of magnitude increase in red fluorescence (580-650 nm). The proposed dye instantly stains target cellular proteins fused with FAST, washes out in a minute timescale, and exhibits higher photostability of the fluorescence signal in confocal and widefield microscopy, in contrast with previously published fluorogen:FAST complexes.


Asunto(s)
Colorantes Fluorescentes/química , Proteínas Fluorescentes Verdes/química , Rodanina/análogos & derivados , Núcleo Celular/ultraestructura , Fluorescencia , Células HEK293 , Células HeLa , Humanos , Microscopía Confocal , Microscopía Fluorescente , Imagen Óptica
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA