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An ascorbic acid sensor based on cadmium sulphide quantum dots.

We present a Förster resonance energy transfer (FRET)-based fluorescence detection of vitamin C [ascorbic acid (AA)] using cadmium sulphide quantum dots (CdS QDs) and diphenylcarbazide (DPC). Initially, DPC was converted to diphenylcarbadiazone (DPCD) in the presence of CdS QDs to form QD-DPCD. This enabled excited-state energy transfer from the QDs to DPCD, which led to the fluorescence quenching of QDs. The QD-DPCD solution was used as the sensor solution. In the presence of AA, DPCD was converted back to DPC, resulting in the fluorescence recovery of CdS QDs. This fluorescence recovery can …

CdSe nanocrystal based chem-/bio- sensors.

Semiconductor nanocrystals (NCs) have found application in biology mostly as optical imaging agents where the photophysical properties of th … chemical means. Signal transduction in these chem-bio (CB) sensitive NCs is derived primarily from energy transfer between the NC and the external agent, which functions as the energy transfer acceptor or donor. Signaling may be obtained by directly detecting luminescence from the NC and/or the conjugate. New developments for the use of NCs as gain materials in …

Diastereoselective and Stereodivergent Synthesis of 2-Cinnamylpyrrolines Enabled by Photoredox-Catalyzed Iminoalkenylation of Alkenes.

A photoredox-catalyzed iminoalkenylation of γ-alkenyl O-acyl oximes has been developed. Readily available alkenylboronic acids serve as alkenylation reagents, leading to densely functionalized pyrrolines. Both (E)- and (Z)-cinnamylpyrrolines are accessible depending on the reaction solvent. In dichloromethane, (E)-cinnamylpyrrolines are produced through a photoredox-mediated single-electron-transfer process. In tetrahydrofuran, (Z)-cinnamylpyrrolines are generated by photocatalytic contra-thermodynamic E-to-Z isomerization of (E)-cinnamylpyrrolines though an energy-transfer pathway. Two stereo

Electron transfer between cytochrome c and metal hexacyanide complexes. Effect of thermodynamic driving force on the electron transfer rate.

The electron transfer reactions between ferrocytochrome c and three isomorphic hexacyanide complexes, [Fe(CN)6]3-, [Os(CN)6]3- and [Ru(CN)6]3-, have been studied using the method of photoexcitation. The transfer rates for [Os(CN)6]3- and [Ru(CN)6]3- are, respectively, about 45- and 200-times higher than that of [Fe(CN)6]3-. A reorganization energy of approx. 0.8 eV was found for the cytochrome c-hexacyanide system when the data were analyzed according to the theory of Marcus.

A supramolecular C60S8 adduct: dynamic and interaction energy considerations of an orbiting S8 motif from MD + EDA calculations.

Dynamics of supramolecular complexes serve to rationalize the constant motion inherent to the formation of non-covalent adducts. Here, the C60S8 adduct is evaluated through the combined molecular dynamics energy decomposition analysis approach (MD + EDA), unraveling the constant orbit-like motion of S8 around the C60 fullerene globe, showing comparable supramolecular interaction energies for the entire dynamic process, arising from a balance between stabilizing (electrostatic, London dispersion, orbital) and destabilizing (Pauli repulsion) forces. Thus, molecular dynamics simulations reveal th

SAMPL7 blind challenge: quantum-mechanical prediction of partition coefficients and acid dissociation constants for small drug-like molecules.

The physicochemical properties of a drug molecule determine the therapeutic effectiveness of the drug. Thus, the development of fast and accurate theoretical approaches for the prediction of such properties is inevitable. The participation to the SAMPL7 challenge is based on the estimation of logP coefficients and pKa values of small drug-like sulfonamide derivatives. Thereby, quantum mechanical calculations were carried out in order to calculate the free energy of solvation and the transfer energy of 22 drug-like compounds in different environments (water and n-octanol) by employing the SMD s

First theoretical framework for highly efficient photovoltaic parameters by structural modification with benzothiophene-incorporated acceptors in dithiophene based chromophores.

Now a days, researchers are constantly doing efforts to upgrade the performance of solar based devices with the aim of increasing the role of photovoltaic materials in modern hi-tech optoelectronic applications. Realizing the recent energy conditions across the globe, research is diverted from fullerene to non-fullerene electron acceptor moieties in this era, considering their remarkable contribution in organic solar cells (OSCs). Therefore, we designed seven novel non-fullerene fused ring electron acceptor chromophores (MD2-MD8) from DOC2C6-2F by structural tailoring with different acceptors

Spin-Polarized Anthracene Triplet States Sensitized by Si QDs Revealed by Time-Resolved EPR Spectroscopy.

Photoexcited quantum dot (QD)-chromophore hybrid systems hold great promise for photon upconversion, a process that could significantly boost the efficiency of solar energy technologies and be useful for spintronics and quantum information science. However, the magnetic interactions that govern the generation and transfer of spin polarization in these systems are not well understood. Here, we report the first time-resolved electron paramagnetic resonance (EPR) study of triplet energy transfer (TET) in colloidal Si QDs conjugated with two anthracene-based organic molecules: 9-ethylanthracene an…

Emerging Manufacturing Technologies in Freeze-Drying of Pharmaceuticals.

Freeze-drying of pharmaceutical products is an energy-intensive operation in pharmaceutical manufacturing. Emerging process-intensification and continuous-manufacturing technologies are now reshaping this traditionally static process. Among these, microwave-assisted freeze-drying, suspended-vial freeze-drying, and spin freeze-drying have demonstrated substantial reductions in cycle time, i.e., up to 80%-90%, while maintaining product stability and uniformity. These approaches enhance heat and mass transfer by replacing conduction through fixed shelves with volumetric or radiative energy delive

Модификация РНК не позволяет расширить кодон-антикодонное взаимодействие облегчить +1 Смена рамы.

Закон о внесении изменений после записи в РНК путем стабилизации функционального соответствия РНК. Хотя их роль в декодировании генератора РНК (mRNA) хорошо установлена, менее ясно, как перенос изменений РНК (tRNA) за пределы антикодона способствует стабильности tRNA и точному синтезу белка. Отсутствие таких изменений приводит к ошибкам в переводе, в том числе к смене mRNA. Интегрировав передачу энергии одним молекулярного флуоресцентного резонанса и криогенную электронную микроскопию, мы продемонстрируем, что N1-methylguanosine (м1G) модификация в положении 37 Эшеричиа коли tRNAProL необходим

Совпадение в аннотации оригинала
RNA post-transcriptional modifications act by stabilizing the functional conformations of RNA. While their role in messenger RNA (mRNA) deco … slation errors, including mRNA frameshifting. By integrating single-molecule fluorescence resonance energy transfer and cryogenic electron microscopy, we demonstrate that the N1-methylguanosine (m1G) modification at position 37 of Escherichia coli tRNAProL is necessary and sufficient for modulating the conformational energy of this tRNA on the ribosome so as to s …

Cationic Cyanostilbene-Induced B-Z DNA Transition in Calf-Thymus DNA: Modulation of FRET in DNA Co-Assemblies.

Cationic cyanostilbenes (CSs) with variable peripheral alkyl chains demonstrated groove binding to calf-thymus DNA (ctDNA). This led to a va … uch a structural transition in ctDNA. Moreover, the CS-DNA ensembles demonstrated Förster resonance energy transfer (FRET) to intercalated acceptor dyes, and the energy transfer efficiency was dependent on the structural form of the ctDNA.

Optically controlling the competition between spin flips and intersite spin transfer in a Heusler half-metal on sub-100-fs time scales.

The direct manipulation of spins via light may provide a path toward ultrafast energy-efficient devices. However, distinguishing the microscopic processes that can occur during ultrafast laser excitation in magnetic alloys is challenging. Here, we study the Heusler compound Co2MnGa, a material that exhibits very strong light-induced spin transfers across the entire M-edge. By combining the element specificity of extreme ultraviolet high-harmonic probes with time-dependent density functional theory, we disentangle the competition between three ultrafast light-induced processes that occur in Co2

NIR-II bioluminescence for in vivo high contrast imaging and in situ ATP-mediated metastases tracing.

Bioluminescence imaging has been widely used in life sciences and biomedical applications. However, conventional bioluminescence imaging usually operates in the visible region, which hampers the high-performance in vivo optical imaging due to the strong tissue absorption and scattering. To address this challenge, here we present bioluminescence probes (BPs) with emission in the second near infrared (NIR-II) region at 1029 nm by employing bioluminescence resonance energy transfer (BRET) and two-step fluorescence resonance energy transfer (FRET) with a specially designed cyanine dye FD-1029. The…

Anthrax toxin complexes: heptameric protective antigen can bind lethal factor and edema factor simultaneously.

The 83 kDa protective antigen (PA(83)) component of anthrax toxin, after proteolytic activation, self-associates to form ring-shaped heptamers ([PA(63)](7)) that bind and aid delivery of the Edema Factor (EF) and Lethal Factor (LF) components to the cytosol. Here we show using fluorescence (Förster) resonance energy transfer that a molecule of [PA(63)](7) can bind EF and LF simultaneously. We labeled EF and LF with an appropriate donor/acceptor pair and found quenching of the donor and an increase in sensitized emission of the acceptor when, and only when, a mixture of the labeled proteins was…

Thermodynamics of the distribution of some carboxylic acids between organic solvents and a perchlorate solution.

The distribution of formic, benzoic and 4-methylbenzoic acids between a 0.1 mol dm(-3) (Na+, H+)ClO4- solution and octanol and carbon tetrachloride was studied at five different temperatures of 10 - 30 degrees C. The thermodynamic parameters for the transfer process of monomeric acid between two phases and for the dimerization of monomeric acid in carbon tetrachloride (deltaH and deltaS) were evaluated from the van't Hoff isochore. The free-energy change for the transfer of a methylene group from water to organic solvents was entropically controlled, irrespective of the organic solvents. The d

Active regulation of synergistic interfacial materials for solar water purification.

Coupling solar interfacial evaporation with photocatalysis provides a dual-functional strategy for simultaneous freshwater production and pollutant remediation. However, the current strategy of the passive stacking of functional layers faces bottlenecks due to inherent mechanistic conflicts, specifically manifested as the heat-adsorption paradox, mass transfer mismatch, and light energy competition, often resulting in a mutual loss of overall efficiency (1+1<2). To overcome these specific limitations, we propose a paradigm shift from passive assembly to active regulation. This review defines t

Molecular structure controls sunlight-driven photodegradation and persistence of trace organic contaminants in surface waters.

Sunlight-induced phototransformation plays a key role in the attenuation of trace organic contaminants (TrOCs) in surface waters, yet rapid … lected TrOCs varied widely among chemical classes and strongly influence their sunlight reactivity. Energy transfer pathways with dissolved organic matter and oxygen were broadly favorable, whereas most electron transfer pathways were thermodynamically unfavorable under environmentally relevant conditions. Across the 150 TrOCs, the lowest triplet excitation energ …

Quasi-Solid Iodine Electrode for High-Areal-Capacity Aqueous Iodine Batteries.

Zinc-iodine batteries (ZIBs), operating via either the two-electron I-/I0 (2eZIB) or four-electron I-/I0/I+ (4eZIB) redox couples, offer high theoretical energy density and sustainability. However, achieving practical high energy density requires high iodine content and mass loading, which slow iodine redox kinetics and exacerbate I+ hydrolysis and shuttling. Here, we present a robust quasi-solid electrode (QE) architecture in which molecularly dispersed iodine that spatially confined within a polyacrylonitrile (PAN)-N-methyl-2-pyrrolidone (NMP) gel network-otherwise volatile-enabling high iod

Controlling the Stereodynamics of the F- + NH2Cl SN2 Reaction by Vibrational Excitation: A Quasi-Classical Study.

Here we report how specific reactant vibrational excitations impact the dynamics of the F- + NH2Cl reaction, with a special emphasis on the stereoselectivity of its SN2 channel, by performing quasi-classical trajectory simulations on a high-quality ab initio analytical potential energy surface. Exciting the N-Cl stretching is found to enhance the SN2 reactivity the most, while N-H stretching excitation is the most efficient in promoting proton transfer. The stereospecificity of the title reaction can be drastically manipulated by exciting (1) the umbrella vibration, which facilitates repeated

An NIR-IIb emissive transmembrane voltage nano-indicator for the optical monitoring of electrophysiological activities in vivo.

In vivo transmembrane-voltage detection reflected the electrophysiological activities of the biological system, which is crucial for the diagnosis of neuronal disease. Traditional implanted electrodes can only monitor limited regions and induce relatively large tissue damage. Despite emerging monitoring methods based on optical imaging have access to signal recording in a larger area, the recording wavelength of less than 1000 nm seriously weakens the detection depth and resolution in vivo. Herein, a Förster resonance energy transfer (FRET)-based nano-indicator, NaYbF4:Er@NaYF4@Cy7.5@DPPC (Cy7…