Time-resolved transient optical and electron paramagnetic resonance spectroscopic studies of electron donor-acceptor thermally activated delayed fluorescence emitters based on naphthalimide-phenothiazine dyads.

The photophysics of naphthalimide (NI)-phenothiazine (PTZ) dyads were investigated as electron donor-acceptor (D-A) thermally activated delayed fluorescence (TADF) emitters. Femtosecond transient absorption (fs-TA) spectra show that the photophysical processes in non-polar solvents are in singlet localized state (LE, = 0.8 ps) → Franck-Condon singlet charge separation state (CS, = 7.

The Photophysics of Naphthalimide-Phenoselenazine Electron Donor-Acceptor Dyads: Revisiting the Heavy-Atom Effect in Thermally Activated Delayed Fluorescence.

We prepared thermally activated delayed fluorescence (TADF) emitter dyads, NI-PTZ, NI-PTZ-2Br and NI-PSeZ, with naphthalimide (NI) as electron acceptor and 10H-phenothiazine (PTZ) or 10H-phenoselenazine (PSeZ) as electron donor to study the heavy-atom effect on the intersystem crossing (ISC) and reverse ISC (rISC) in the TADF emitters. The delayed fluorescence lifetimes of the dyads containing heavy atoms ( =5.9 μs for NI-PSeZ and =16.

Intersystem Crossing, Photo-Induced Charge Separation and Regioisomer-Specific Excited State Dynamics in Fully Rigid Spiro Rhodammine-Naphthalene/Anthraquinone Electron Donor-Acceptor Dyads.

We prepared a series fully rigid spiro electron donor-acceptor orthogonal dyads, with closed form of rhodamine (Rho) as electron donor and naphthalene (Np)/anthraquinone (AQ) as electron acceptor, to access the long-lived triplet charge separation (CS) state, via the electron spin control method. We found strong dependency of the photophysical property of the dyads on the amino substitution positions of the Np chromophores in the dyads 1,8-DaNp-Rho and 2,3-DaNp-Rho. Nanosecond transient absorption (ns-TA) spectra show the population of the LE state (lifetime: 47 μs) for 2,3-DaNp-Rho, however, long-lived CS state was observed (τ=0.

Introduction to Special Issue "The Self-Assembly and Design of Polyfunctional Nanosystems 3.0".

Stimulus-responsive systems allowing for the controlled release of drugs [...

Crystal structure of the GDP-bound GTPase Era from Staphylococcus aureus.

GTPase Era from Staphylococcus aureus belongs to the TRAFAC superfamily of the TrmE-Era-EngA-EngB-Septin-like GTPases class and plays a significant role in the vital activity of this pathogenic microorganism as a maturation factor of the 30S ribosome subunit. However, the functions of this protein are not fully understood, making it a promising object for further study. Here, the 2.

Electron Spin Dynamics of the Intersystem Crossing in Aminoanthraquinone Derivatives: The Spectral Telltale of Short Triplet Excited States.

We studied the excited state dynamics of two bis-amino substituted anthraquinone (AQ) derivatives, with absorption in the visible spectral region, which results from the attachment of a electron-donating group to the electron-deficient AQ chromophore. Femtosecond transient absorption spectra show that intersystem crossing (ISC) takes place in 190-320 ps, and nanosecond transient absorption spectra demonstrated an unusually short triplet state lifetime (2.06-5.

Thermal Inactivation, Denaturation and Aggregation Processes of Papain-Like Proteases.

The investigation into the behavior of ficin, bromelain, papain under thermal conditions holds both theoretical and practical significance. The production processes of medicines and cosmetics often involve exposure to high temperatures, particularly during the final product sterilization phase. Hence, it's crucial to identify the "critical" temperatures for each component within the mixture for effective technological regulation.

Phosphine-Catalyzed Synthesis and Cytotoxic Evaluation of Michael Adducts of the Sesquiterpene Lactone Arglabin.

A general method for chemo- and diastereoselective modification of anticancer natural product arglabin with nitrogen- and carbon-centered pronucleophiles under the influence of nucleophilic phosphine catalysts was developed. The locked s-cis-geometry of α-methylene-γ-butyrolactone moiety of arglabin favors for the additional stabilization of the zwitterionic intermediate by electrostatic interaction between phosphonium and enolate oxygen centers, leading to the unprecedentedly high efficiency of the phosphine-catalyzed Michael additions to this sesquiterpene lactone. Using n-BuP as the catalyst, pyrazole, phthalimide, 2-oxazolidinone, 4-quinazolinone, uracil, thymine, cytosine, and adenine adducts of arglabin were obtained.

Biotechnological Key Genes of the MGMM8 Genome: Genes for Bioremediation, Antibiotics, Plant Protection, and Growth Stimulation.

Anthropogenic pollution, including residues from the green revolution initially aimed at addressing food security and healthcare, has paradoxically exacerbated environmental challenges. The transition towards comprehensive green biotechnology and bioremediation, achieved with lower financial investment, hinges on microbial biotechnology, with the genus emerging as a promising contender. The significance of fully annotating genome sequences lies in comprehending strain constituents, devising experimental protocols, and strategically deploying these strains to address pertinent issues using pivotal genes.

A Rational Way to Control the Triplet State Wave Function Confinement of Organic Chromophores: Effect of the Connection Sites and Spin Density Distribution-Guided Molecular Structure Design Principles in Bodipy Dimers.

To study the intersystem crossing (ISC) and the spatial confinement of the triplet excited states of organic chromophores, we prepared a series of Bodipy dimers. We found that the connection position of the two units has a significant effect on the absorption and fluorescence. Singlet oxygen quantum yields of 3.

Low-temperature motion of the scandium bimetal in endofullerene Sc@C(CHPh).

The spin decoherence of the scandium bimetal in Sc@C(CHPh) is studied at low temperatures (20-120 K) by the electron spin echo technique. The correlation between the magnetic quantum number of the total spin state of the scandium nuclei and the decay rates is established. For the total spin = 5, a decrease of the phase relaxation time by a factor of two is observed by changing the transition from = -1 to = +1 and = -3 at 120 K.

Oxygen-Containing Quaternary Phosphonium Salts (oxy-QPSs): Synthesis, Properties, and Cellulose Dissolution.

In the present study, the synthesis of oxygen-containing quaternary phosphonium salts (oxy-QPSs) was described. Within this work, structure-property relationships of oxy-QPSs were estimated by systematic analysis of physical-chemical properties. The influence of the oxygen-containing substituent was examined by comparing the properties of oxy-QPSs in homology series as well as with phosphonium analog-included alkyl side chains.

Activation of TRPV1 Channels Inhibits the Release of Acetylcholine and Improves Muscle Contractility in Mice.

TRPV1 represents a non-selective transient receptor potential cation channel found not only in sensory neurons, but also in motor nerve endings and in skeletal muscle fibers. However, the role of TRPV1 in the functioning of the neuromuscular junction has not yet been fully established. In this study, the Levator Auris Longus muscle preparations were used to assess the effect of pharmacological activation of TRPV1 channels on neuromuscular transmission.

Preparation of Xanthene-TEMPO Dyads: Synthesis and Study of the Radical Enhanced Intersystem Crossing.

We prepared a rhodamine-TEMPO chromophore-radical dyad (RB-TEMPO) to study the radical enhanced intersystem crossing (REISC). The visible light-harvesting chromophore rhodamine is connected with the TEMPO (a nitroxide radical) via a C-N bond. The UV-vis absorption spectrum indicates negligible electron interaction between the two units at the ground state.

Characterization of a Novel Strain MGMM1 Based on Full Genome Analysis and Phenotypic Properties for Biotechnological Applications.

species have gained much attention based on their phenotypic characteristics and their genetic architecture as biological control agents and plant growth-promotor with bioremediation potential. In this study, we analyzed the whole genome of a novel strain, MGMM1, isolated from the rhizosphere of a weed plant () and assayed its phenotypic characteristics, as well as antifungal and biocontrol ability. The whole genome analysis of MGMM1 identified 4259 putative coding sequences, with an encoding density of 95.

Observation of Long-Lived Charge-Separated States in Anthraquinone-Phenothiazine Electron Donor-Acceptor Dyads: Transient Optical and Electron Paramagnetic Resonance Spectroscopic Studies.

We prepared a series of phenothiazine (PTZ)-anthraquinone (AQ) electron donor-acceptor dyads to study the relationship between molecular structures and the possibility of charge transfer (CT) and intersystem crossing (ISC). As compared to the previously reported dyad with a direct connection of two units via a C-N single bond, the PTZ and AQ units are connected via a -phenylene or -biphenylene linker. Conformation restriction is imposed by attaching -methyl groups on the phenylene linker.

Induced Expression of and Genes Associated with Penconazole and Fludioxonil Resistance in the Potato Pathogen .

Preventing antifungal resistance development and identifying pathogens with high, medium, and low risk of resistance development to a particular fungicide or fungicide class is crucial in the fight against phytopathogens. We characterized the sensitivity of potato wilt-associated isolates to fludioxonil and penconazole and assessed the effect of these fungicides on the expression of fungal sterol-14-α-demethylase ( and histidine kinase () genes. Penconazole stunted the growth of strains at all concentrations used.

Phosphate Solubilization and Plant Growth Promotion by Soil Isolates.

Phosphate solubilizing microorganisms (PSMs) in soil have been shown to reduce mineral phosphate fertilizer supplementation and promote plant growth. Nevertheless, only several P-solubilizing microorganisms capable of solubilizing both organic and mineral sources of soil phosphorus have been identified up to now. The aim of this study was to evaluate the inorganic soil phosphate solubilizing activity of phytate-hydrolyzing soil isolates.

Extent of N-Terminus Folding of Semenogelin 1 Cleavage Product Determines Tendency to Amyloid Formation.

It is known that four peptide fragments of predominant protein in human semen Semenogelin 1 (SEM1) (SEM1(86-107), SEM1(68-107), SEM1(49-107) and SEM1(45-107)) are involved in fertilization and amyloid formation processes. In this work, the structure and dynamic behavior of SEM1(45-107) and SEM1(49-107) peptides and their N-domains were described. According to ThT fluorescence spectroscopy data, it was shown that the amyloid formation of SEM1(45-107) starts immediately after purification, which is not observed for SEM1(49-107).

Origin of intersystem crossing in highly distorted organic molecules: a case study with red light-absorbing ,,,-boron-chelated Bodipys.

To explore the relationship between the twisted π-conjugation framework of aromatic chromophores and the efficacy of intersystem crossing (ISC), we have studied a ,,,-boron-chelated Bodipy derivative possessing a severely distorted molecular structure. Surprisingly, this chromophore is highly fluorescent, showing inefficient ISC (singlet oxygen quantum yield, = 12%). These features differ from those of helical aromatic hydrocarbons, where the twisted framework promotes ISC.

Long-Lived Charge Separated States in Anthraquinone-Phenothiazine Dyads: Synthesis and Study of the Photophysical Property by Using Transient Optical and Magnetic Resonance Spectroscopies.

In order to obtain long-lived charge separated (CS) states in electron donor-acceptor dyads, herein we prepared a series of anthraquinone (AQ)-phenothiazine (PTZ) dyads, with adamantane as the linker. UV-vis absorption spectra show negligible electronic interaction between the AQ and PTZ units at ground state, yet charge transfer (CT) emission bands were observed. Nanosecond transient absorption shows that the AQ state is populated upon photoexcitation for AQ-PTZ in cyclohexane (CHX), but in acetonitrile (ACN) a CS state is formed.