Microglia and Astrocytes Responses Contribute to Alleviating Inflammatory Damage by Repetitive Transcranial Magnetic Stimulation in Rats with Traumatic Brain Injury.

Repetitive transcranial magnetic stimulation (rTMS) is a therapeutic strategy that shows promise in ameliorating the clinical sequelae following traumatic brain injury (TBI). These improvements are associated with neuroplastic changes in neurons and their synaptic connections. However, it has been hypothesized that rTMS may also modulate microglia and astrocytes, potentially potentiating their neuroprotective capabilities. This study aims to investigate the effects of high-frequency rTMS on microglia and astrocytes that may contribute to its neuroprotective effects. Feeney's weight-dropping method was used to establish rat models of moderate TBI. To evaluate the neuroprotective effect of high frequency rTMS on rats by observing the synaptic ultrastructure and the level of neuron apoptosis. The levels of several important inflammation-related proteins within microglia and astrocytes were assessed through immunofluorescence staining and western blot. Our findings demonstrate that injured neurons can be rescued through the modulation of microglia and astrocytes by rTMS. This modulation plays a key role in preserving the synaptic ultrastructure and inhibiting neuronal apoptosis. Among microglia, we observed that rTMS inhibited the levels of proinflammatory factors (CD16, IL-6 and TNF-α) and promoted the levels of anti-inflammatory factors (CD206, IL-10 and TNF-ß). rTMS also reduced the levels of pyroptosis within microglia and pyroptosis-related proteins (NLRP3, Caspase-1, GSDMD, IL-1ß and IL-18). Moreover, rTMS downregulated P75NTR expression and up-regulated IL33 expression in astrocytes. These findings suggest that regulation of microglia and astrocytes is the mechanism through which rTMS attenuates neuronal inflammatory damage after moderate TBI.

A molecular descriptor of a shallow potential energy surface for the ground state to achieve narrowband thermally activated delayed fluorescence emission.

Narrowband thermally activated delayed fluorescence (TADF) molecules have extensive applications in optoelectronics, biomedicine, and energy. The full-width at half-maximum (FWHM) holds significant importance in assessing the luminescence efficiency and color purity of TADF molecules. The goal is to achieve efficient and stable TADF emissions by regulating and optimizing the FWHM. However, a bridge from the basic physical parameters (such as geometric structure and reorganization energy) to the macroscopic properties (delayed fluorescence, efficiency, and color purity) is needed and it is highly necessary and urgent to explore the internal mechanisms that influence FWHM. Herein, first-principles calculations coupled with the thermal vibration correlation function (TVCF) theory were performed to study the energy consumption processes of the excited states for the three TADF molecules (2,3-POA, 2,3-DPA, and 2,3-CZ) with different donors; inner physical parameters affecting the FWHM were detected. By analyzing the basic geometric and electronic structures as well as the transition properties and reorganization energies, three main findings in modulating FWHM were obtained, namely a large local excitation (LE) proportion in the first singlet excited state is advantageous in reducing FWHM, a donor group with weak electron-donating ability is beneficial for achieving narrowband emission, and small reorganization energies for the ground state are favorable for reducing FWHM. Thus, wise molecular design strategies to achieve efficient narrowband TADF emission are theoretically proven and proposed. We hope that these results will promote an in-depth understanding of FWHM and accelerate the development of high color purity TADF emitters.

Modulation of luminescence properties of circularly polarized thermally activated delayed fluorescence molecules with axial chirality by donor engineering.

Multifunctional thermally activated delayed fluorescence (TADF) materials are currently a trending research subject for luminescence layer materials of organic light-emitting diodes (OLEDs). Among these, circularly polarized thermally activated delayed fluorescence (CP-TADF) materials have the advantage of being able to directly achieve highly efficient circularly polarized luminescence (CPL). The simultaneous integration of outstanding luminescence efficiency and excellent luminescence asymmetry factor (glum) is a major constraint for the development of CP-TADF materials. Therefore, on the basis of first-principles calculations in conjunction with the thermal vibration correlation function (TVCF) method, we study CP-TADF molecules with different donors to explore the feasibility of using the donor substitution strategy for optimizing the CPL and TADF properties. The results indicate that molecules with the phenothiazine (PTZ) unit as the donor possess small energy difference, a great spin-orbit coupling constant and a rapid reverse intersystem crossing rate, which endow them with remarkable TADF features. Meanwhile, compared with the reported molecules, the three designed molecules exhibit better CPL properties with higher glum values. Effective molecular design strategies by donor engineering to modulate the CPL and TADF properties are theoretically proposed. Our findings reveal the relationship between molecular structures and luminescence properties of CP-TADF molecules and further provide theoretical design strategies for optimizing the CPL and TADF properties.

Theoretical design and performance prediction of deep red/near-infrared thermally activated delayed fluorescence molecules with through space charge transfer.

Thermally activated delayed fluorescence (TADF) molecules with through-space charge transfer (TSCT) have attracted much attention in recent years because of their ability to simultaneously reduce the energy difference (ΔEST) and enlarge the spin-orbit coupling (SOC). In this paper, 40 molecules are theoretically designed by changing the different substitution positions of the donors and acceptors, and systematically investigated based on the first-principles calculations and excited-state dynamics study. It is found that the emission wavelengths of v-shaped molecules with intramolecular TSCT are larger than those of the molecules without TSCT. Therefore, the intramolecular TSCT can induce the red-shift of the emission and realize the deep-red/near-infrared emission. Besides intramolecular TSCT can simultaneously increase the SOC as well as the oscillator strength and reduce the ΔEST. In addition, PXZ or PTZ can also favor the realization of smaller ΔEST and red-shift emission. Our calculations suggest that intramolecular TSCT and suitable donors (-PXZ or -PTZ) are an effective strategy for the design of efficient deep red/near-infrared TADF emitters.

Role of Bridging Groups in Regulating the Luminescence and Charge Transfer Properties of Thermally Activated Delayed Fluorescence Molecules: A Theoretical Perspective.

Organic emitters with a simultaneous combination of aggregation-induced emission (AIE) and thermally activated delayed fluorescence (TADF) characteristics are in great demand due to their excellent comprehensive performances toward efficient organic light-emitting diodes (OLEDs), biomedical imaging, and the telecommunications field. However, the development of efficient AIE-TADF materials remains a substantial challenge. In this work, light-emitting properties of two AIE-TADF molecules with different bridging groups ICz-BP and ICz-DPS are theoretically investigated in the solid state with the combined quantum mechanics/molecular mechanics (QM/MM) method and the thermal vibration correlation function (TVCF) theory. The research indicates that the C═O bridging bond in ICz-BP is more favorable than the S═O bridging bond in ICz-DPS for enhancing the planarity of the acceptor, increasing conjugation, and thereby elevating the transition dipole moment density. Simultaneously, the stacking pattern of ICz-BP in the solid facilitates a reduction in energy gap between S1 and T1 (ΔEST), achieving rapid reverse intersystem crossing rate (kRISC). Furthermore, compared to toluene, the stacking patterns of ICz-BP and ICz-DPS in the solid effectively suppress the out-of-plane wagging vibration of the acceptor, thereby inhibiting the loss of nonradiative energy in the excited state and realizing aggregation-induced emission. Moreover, the charge transport properties of both electrons and holes in ICz-BP are found to be higher than the corresponding rates in ICz-DPS, attributed to the smaller internal reorganization energy of ICz-BP in the solid state. Additionally, the calculations reveal a more balanced charge transport characteristic in ICz-BP, contributing to efficient exciton recombination and emission and ultimately mitigating efficiency roll-off. Based on these computational results, we aim to unveil the relationship between molecular structure and light-emitting properties, aiding in the design and development of efficient AIE-TADF devices.

Theoretical Insights into the Photophysical Properties of 4CzIPN Doped in Different Hosts: A Multiscale Study.

As a typical thermally activated delayed fluorescence (TADF) emitter with green emission, 4CzIPN has attracted much attention recently. Most studies indicated that 4CzIPN doped in different hosts presented different performances; thus, the hosts should have an obvious influence on its photophysical properties. Herein, the influence of four kinds of hosts, including m-CzPym, m-CzTrz, p-CzPym, and p-CzTrz, on the photophysical properties of 4CzIPN is investigated. Molecular dynamics simulations were performed to simulate the host-guest conformations, and the photophysical properties were studied using the combined quantum mechanics/molecular mechanics method coupled with the thermal-vibration correlation function method. It is found that 4CzIPN in doped films has larger transition dipole moments and spin-orbital coupling constants compared to that in nondoped films. Faster radiative decay, intersystem crossing rates, and higher fluorescence efficiency could be obtained in doped films. Our work helps to better understand the photophysical properties of 4CzIPN in doped films and may favor the design of new hosts.

Opposite evolution of pathogenicity driven by in vivo wzc and wcaJ mutations in ST11-KL64 carbapenem-resistant Klebsiella pneumoniae.

AIMS: To investigate the in vivo evolution of the mucoid-phenotype of ST11-KL64 carbapenem-resistant Klebsiella pneumoniae (CRKP) isolated from the same patients and gain insights into diverse evolution and biology of these strains. METHODS: Whole genome sequencing and bioinformatic analysis were used to determine the mutation involved in the mucoid phenotype of ST11-KL64 CRKP. Gene knockout, bacterial morphology and capsular polysaccharides (CPS) extraction were used to verify the role of wzc and wcaJ in the mucoid phenotypes. Antimicrobial susceptibility, growth assay, biofilm formation, host cell adhesion and virulence assay were used to investigate the pleiotropic role of CPS changes in ST11-KL64 CRKP strains. RESULTS: Mutation of wzc S682N led to hypermucoid phenotype, which had negative impact on bacterial fitness and resulted in reduced biofilm formation and epithelial cell adhesion; while enhanced resistance to macrophage phagocytosis and virulence. Mutations of wcaJ gene led to non-mucoid phenotype with increased biofilm formation and epithelial cell adhesion, but reduced resistance of macrophage phagocytosis and virulence. Using virulence gene knockout, we demonstrated that CPS, rather than the pLVPK-like virulence plasmid, has a greater effect on mucoid phenotypic changes. CPS could be used as a surrogate marker of virulence in ST11-KL64 CRKP strains. CONCLUSIONS: ST11-KL64 CRKP strains sacrifice certain advantages to develop pathogenicity by changing CPS with two opposite in vivo evolution strategies.

Aggregation Effect on Multiperformance Improvement in Aryl-Armed Phenazine-Based Emitters.

The concept of aggregate science was proposed to explain changes in materials performance that accompany the generation of aggregates, but aggregation-triggered multifunction improvements in a class of materials have rarely been reported. Herein, we present the first report of a new class of multifunctional aggregation-induced emission (AIE) luminogens (AIEgens) based on 5,10-diarylphenazine (DPZ) derivates with full-wavelength emission. Intriguingly, multiple properties, such as fluorescence intensity and free radical and type I reactive oxygen species (ROS) efficiencies, could be simultaneously activated from the unimolecular level to the aggregate state. The mechanisms of this multiple performance improvement are discussed in detail based on sufficient performance characterization, and some of the newly prepared AIEgens exhibited toxicity to cancer cells during photodynamic therapy. This work systematically demonstrates the positive effect of aggregation on improving multiple functions of materials, which is expected to promote the development of aggregate science theory for the design of multifunctional materials.

Theoretical exploration of the bromine substitution effect and hydrostatic pressure responsive mechanism for room temperature phosphorescence.

Stimulus-responsive organic room temperature phosphorescence (RTP) materials with long lifetimes, high efficiencies and tunable emission properties have broad applications. However, the amounts and species of efficient RTP materials are far from meeting the requirements and the inner stimulus-responsive mechanisms are unclear. Therefore, developing efficient stimulus-responsive RTP materials is highly desired and the relationship between the molecular structures and luminescent properties of RTP materials needs to be clarified. Based on this point, the influences of different substitution sites of Br on the luminescent properties of RTP molecules are studied by the combined quantum mechanics and molecular mechanics (QM/MM) coupled with thermal vibration correlation function (TVCF) theory. Moreover, the hydrostatic pressure effect on the efficiencies and lifetimes is explored and the inner mechanism is illustrated. The results show that, for the exciton conversion process, the o-substitution molecule possesses the largest spin-orbit coupling (SOC) value (〈S1|Hso|T1〉) in the intersystem crossing (ISC) process and this is conducive to the accumulation of triplet excitons. However, for the energy consumption process, the large SOC value (〈S0|Hso|T1〉) for the p-substitution molecule brings a fast non-radiative decay rate, and the small SOC value for the m-substitution molecule generates a decreased non-radiative decay rate which is helpful for realizing long lifetime emission. Keeping with this perspective, the conflict between high exciton utilization and long RTP emission needs to be balanced rather than enhancing the SOC effect by simply adding heavy atoms in RTP systems. Through regulating the molecular stacking modes by the hydrostatic pressure effect, the inner stimulus-responsive mechanism is revealed. The data of 〈S1|Hso|T1〉 in the ISC process remain almost unchanged, while 〈S0|Hso|T1〉 values and transition dipole moments are sensitive to the hydrostatic pressure. Under 1 GPa, the RTP molecule achieves a maximum efficiency (81.17%) and long lifetime (2.72 ms) with the smallest SOC and decreased non-radiative decay rate. To our knowledge, this is the first time that the hydrostatic pressure responsive mechanism for RTP molecules is revealed from a theoretical perspective, and the relationships between molecular structures and luminescent properties are detected. Our work could facilitate the development of high performance RTP molecules and expand their applications in multilevel information encryption.

Regulating through space charge transfer in thermally activated delayed fluorescence molecules via donor architectures: theoretical perspective and molecular design.

In recent studies, thermally activated delayed fluorescence (TADF) molecules with a through space charge transfer (TSCT) feature have attracted wide attention. Nevertheless, studies on the substitution effects on the photophysical properties of TSCT-based TADF molecules are insufficient, and the corresponding theoretical investigations and effective molecular design strategies are highly desired. Herein, in order to reveal the inner mechanisms between the substitution effects from the donor unit and the luminescent properties for TSCT-based TADF molecules, the photophysical properties of nine TSCT-based TADF molecules (including one molecule with dual configurations) are theoretically studied. Based on density functional theory (DFT) and time-dependent density functional theory (TD-DFT) coupled with the thermal vibration correlation function (TVCF) method, basic physical parameters such as geometric changes, electron-donating abilities, adiabatic singlet-triplet energy gaps, TSCT ratios, hole and electron distributions and excited state decay rates are calculated and analyzed. The relationships between molecular structures and luminescent properties are determined. Our results show that molecules with carbazole as the donor possess large oscillator strengths and transition dipole moments, and a prominent radiative decay process is determined. Moreover, molecules with phenazine as the donor present small geometric changes, strong electron-donating capability and tiny adiabatic singlet-triplet energy gap, and all these factors contribute to the effective reverse intersystem crossing process (RISC), and this feature makes these molecules promising TSCT-based TADF molecules. Furthermore, dual configurations for 2CTF molecules are determined (2CTF2.1 and 2CTF2.2), and 2CTF2.1 with a large TSCT ratio possessing a fast fluorescence decay process and high luminescence efficiency can be achieved. As for 2CTF2.2 with a small TSCT ratio, a remarkable RISC process is determined and high exciton utilization can be realized. Thus, 2CTF can be regarded as a self-doping TADF molecule and a remarkable TADF feature is detected. Our investigations provide a perspective for experimental measurements and propose an effective design strategy for efficient TSCT-based TADF molecules.

Controllable construction of red thermally activated delayed fluorescence molecules based on a spiro-acridine donor.

Red and near-infrared (NIR) thermally activated delayed fluorescence (TADF) molecules show excellent potential applications in organic light-emitting diodes (OLEDs). Due to the lack of systematic studies on the relationship between molecular structures and luminescence properties, both the species and amounts of red and NIR TADF molecules are far from meeting the requirements for practical applications. Herein, four new efficient molecules (DQCN-2spAs, TPCN-2spAs, DPCN-2spAs and BPCN-2spAs) are proposed and their photophysical properties are theoretically predicted based on first-principles calculations and thermal vibration correlation function (TVCF) theory. The results show that all molecules exhibit red or NIR emissions and they have fast radiative decay rates and reverse intersystem crossing (RISC) rates, and the excellent TADF luminescence properties are predicted. Moreover, based on spiro-acridine (spAs) as the donor unit, the combination with different acceptors can change the dihedral angle between the ground state and the excited state, the bending degree of the donor is positively correlated with the reorganization energy, and this feature can have a great influence on the non-radiative process. Furthermore, based on these theoretical predictions, experimental verifications are performed and the synthesized BPCN-2spAs is confirmed to be an efficient NIR TADF molecule. Thus, the relationships between basic molecular structures and photophysical properties are revealed, a feasible design strategy is applied and four promising red and NIR TADF molecules are proposed. All these results could contribute to the development of red and NIR TADF emitters and OLEDs.

Role of halogen effects and cyclic imide groups in constructing red and near-infrared room temperature phosphorescence molecules: theoretical perspective and molecular design.

Organic room temperature phosphorescence (RTP) has been widely investigated to realize long-lifetime luminescent materials and improvement in their efficiency is a key focus of research, especially for red and near-infrared (NIR) RTP molecules. However, due to the lack of systematic studies on the relationship between basic molecular structures and luminescence properties, both the species and amounts of red and NIR RTP molecules remain far from meeting the requirements of practical applications. Herein, based on density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations, the photophysical properties of seven red and NIR RTP molecules in tetrahydrofuran (THF) and in the solid phase were theoretically studied. The excited state dynamic processes were investigated by calculating the intersystem crossing and reverse intersystem crossing rates considering the surrounding environmental effects in THF and in the solid phase using a polarizable continuum model (PCM) and quantum mechanics and molecular mechanics (QM/MM) method, respectively. The basic geometric and electronic data were obtained, Huang-Rhys factors and reorganization energies were analyzed, and natural atomic orbital was used to calculate the orbital information of the excited states. Simultaneously, the electrostatic potential distribution on molecular surfaces was analyzed. Further, intermolecular interactions were visualized using the molecular planarity binding independent gradient model based on Hirshfeld partition (IGMH). The results showed that the unique molecular configuration has the potential to achieve red and NIR RTP emission. Not only did the substitutions of halogen and sulfur make the emission wavelength red-shifted, but also linking the two cyclic imide groups could further make the emission wavelength longer. Moreover, we found that the emission characteristics of molecules in THF had a similar trend as in the solid phase. Based on this point, two new RTP molecules with long emission wavelengths (645 nm and 816 nm) are theoretically proposed and their photophysical properties are fully analyzed. Our investigation provides a wise strategy to design efficient and long-emission RTP molecules with an unconventional luminescence group.

Multi-resonance thermally activated delayed fluorescence molecules with intramolecular-lock: theoretical design and performance prediction.

Multi-resonance thermally activated delayed fluorescence (MR-TADF) molecules with narrow full width at half maximum (FWHM) have attracted much attention recently. In this work, 36 borane/amine (B/N) type MR-TADF molecules were theoretically designed by using an intramolecular-lock strategy and systematically studied based on first-principles calculations. It was found that intramolecular-lock at different positions and in different manners could induce different luminescent properties. The calculated oscillator strengths for PXZ-L2 and PTZ-L2 locking systems are weaker than that for 2DPABN (without intramolecular-lock), while the Cz-L1 and TMCZ-L1 locking could result in stronger oscillator strength. Though the calculated FWHM of all the systems with intramolecular-lock is higher than that of 2DPABN, the Cz, TMCz and DMAC locking at L1 or L2 would induce relatively small FWHM which is comparable to that of 2DPABN. Our calculation results indicate that intramolecular-lock could enhance the SOC values and decrease the energy gap between the first singlet excited state and the first triplet excited state, which is quite favorable to reverse intersystem crossing. The Cz, TMCz and DMAC locking systems could realize comparable and higher efficiency than 2DPABN, thus higher quantum efficiency could be obtained. Our calculation results indicate that the intramolecular-lock strategy is an effective method to realize the design of highly efficient MR-TADF emitters.

Exploring the luminescence properties and sensing mechanism of a turn-on TADF probe for sulfite.

Fluorescent probes with a microsecond lifetime have attracted much attention in biological detection. The luminescence properties and responsive mechanisms of a probe [DCF-MPYM-lev-H]- for detecting sulfite and its corresponding product [DCF-MPYM-2H]2- are studied based on density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations as well as the thermal vibration correlation function method. It is found that the luminescence efficiency of the probe increases obviously after reacting with sulfite, which is induced by increased radiative decay rates and decreased nonradiative rates. In addition, the thermally activated delayed fluorescence (TADF) properties of products are confirmed by analyzing the spin-orbital constants and energy gaps between the singlet excited states and the triplet excited states. The calculation results favor the understanding of the luminescence properties and responsive mechanism of a turn-on TADF probe for sulfite, which may provide a theoretical reference for the development of new TADF probes.

Genetic analysis of resistance to powdery mildew on 7Mg chromosome of wheat-Aegilops geniculata, development and utilization of specific molecular markers.

BACKGROUND: Powdery mildew caused by Blumeria graminis f. sp. tritici (Bgt) is prevalent in the main wheat-producing regions of China, resulting in severe yield losses in recent years. Mining and utilization of resistant genes from wild relatives of wheat is the most environmentally sound measure to control disease. Aegilops geniculata Roth (2n = 2x = 28, UgUgMgMg) is an essential and valuable disease-resistance gene donor for wheat improvement as a close relative species. RESULTS: In this study, to validate powdery mildew resistance locus on chromosome 7Mg, two genetic populations were constructed and through crossing wheat - Ae. geniculata 7Mg disomic addition line NA0973-5-4-1-2-9-1 and 7Mg (7 A) alien disomic substitution line W16998 with susceptible Yuanfeng175 (YF175, authorized varieties from Shaanxi province in 2005), respectively. Cytological examination, in situ hybridization (ISH), and functional molecular markers analysis revealed that the plants carrying chromosome 7Mg showed high resistance to powdery mildew in both F1 and F2 generation at the seedling stage. Besides, 84 specific markers were developed to identify the plants carrying chromosome 7Mg resistance based on the specific-locus amplified fragment sequencing (SLAF-seq) technique. Among them, four markers were selected randomly to check the reliability in F2 segregating populations derived from YF175/NA0973-5-4-1-2-9-1 and YF175/W16998. In summary, the above analysis confirmed that a dominant high powdery mildew resistance gene was located on chromosome 7Mg of Ae. geniculata. CONCLUSION: The results provide a basis for mapping the powdery mildew resistance gene mapping on chromosome 7Mg and specific markers for their utilization in the future.

Efficient deep red/near-infrared thermally activated delayed fluorescence emitters via molecular reconstruction: theoretical insights.

Thermally activated delayed fluorescence (TADF) molecules with deep-red (DR) and near-infrared (NIR) luminescence show great potential in biomedical sensing/imaging and telecommunications. However, developing efficient DR- and NIR-TADF molecules remains a powerful challenge, and new design strategies are highly desired. Based on 2,3-bis(4-(diphenylamino)phenyl)quinoxaline-5,8-dicarbonitrile (CNQ-TPA), two novel TADF molecules CNQ-b-TPA and CNQ-f-TPA are theoretically constructed through the design strategy of molecular bonding and molecular fusion. The photophysical properties and luminescence mechanisms of the three molecules in toluene and the crystal state are revealed with first-principles calculations and the thermal vibration correlation function (TVCF) method. Compared with CNQ-TPA, CNQ-b-TPA and CNQ-f-TPA can achieve an effective red-shift of intrinsic emission and efficient DR and NIR emission. Remarkably, molecular bonding and molecular fusion not only greatly increase the oscillator strength, but also effectively reduce the energy gap between the first singlet excited state (S1) and the first triplet excited state (T1), resulting in their high radiative and reverse intersystem crossing rate. Moreover, the charge transport properties are studied based on kinetic Monte Carlo simulations. Molecular bonding to balance charge transport is found, enabling ambipolar transport properties. Our work provides a feasible solution to overcome the design limitations of previous DR- and NIR-TADF materials and predicts good candidates for both DR- and NIR-TADF emitters.

A theoretical perspective of the relationship between the structures and luminescence properties of red thermally activated delayed fluorescence molecules.

Orange and red thermally activated delayed fluorescence (TADF) emitters have shown promising applications in organic light emitting diodes (OLEDs) and the bio-medical field. However, both the species and amounts of orange and red molecules are far from meeting the requirement for practical applications; this is due to the lack of systematic studies on the relationship between molecular structures and luminescence properties. Herein, the excited state dynamic processes and photophysical properties of six donor-acceptor (D-A) type orange-red TADF molecules, which possess the same acceptor, are theoretically studied in toluene by using the polarizable continuum model (PCM). Based on density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations coupled with the thermal vibration correlation function (TVCF) method, the adiabatic singlet-triplet energy gaps, natural transition orbital properties, reorganization energies, hole and electron distributions, and the radiative and non-radiative as well as the intersystem crossing (ISC) and reverse intersystem crossing (RISC) processes are theoretically analyzed. The results indicate that remarkable geometric changes between the lowest singlet excited state (S1) and the ground state (S0) are mainly caused by the rotation of the donor unit for NAI-R2, NAI-R3 and NAI-DPAC, and the reorganization energy is mainly contributed by the dihedral angle. However, for NAI-DMAC, BTDMAc-NAI and BFDMAc-NAI, remarkable geometric changes are found in the acceptor unit with large contribution of reorganization energy by bond length. These variations bring different non-radiative energy consumption processes. Moreover, small energy gaps between S1 and the lowest triplet excited state (T1) are determined for all studied molecules and an efficient RISC process is detected. Furthermore, enhanced conjugacy in the donor unit and remarkable intramolecular interactions are determined for BTDMAc-NAI and BFDMAc-NAI, which is helpful to promote the up-conversion process. Our investigations give reasonable explanations for previous experimental measurements and the relationship between basic structures and luminescence properties is revealed, which could facilitate the development of new efficient TADF emitters.

The mechanism of intramolecular halogen bonding enhanced the quantum efficiency of ultralong organic phosphorescence in the aggregated state.

Ultralong organic phosphorescence (UOP) has broad application prospects in many fields, but realizing its high quantum efficiency is still full of challenges. One of the main reasons is that the internal luminescence mechanism is unclear and theoretical investigations to reveal the inner structure-property relationship are highly desired. Herein, the internal mechanism of halogen bonding enhancing the quantum efficiency of UOP is studied through the combination of quantum mechanics and molecular mechanics methods coupled with the thermal vibration correlation function (TVCF) method. Geometric and electronic data are obtained by density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations. Transition properties, energy gaps, intermolecular interactions, excited state dynamics as well as Huang-Rhys factors and reorganization energies are analyzed in detail. The results show that the high phosphorescence quantum efficiency benefits from the fast intersystem crossing (ISC) process and the slow non-radiative decay process. The halogen bonding, which cooperates with the effects of aromatic carbonyl and heavy atoms, not only accelerates the ISC rate by increasing the spin-orbit coupling effect, but also restricts the molecular motion and reduces the non-radiative energy consumption. Furthermore, through wise molecular design, an efficient UOP molecule with fast ISC and slow non-radiative decay rates is proposed. This work provides an insight into realizing efficient UOP emission via intramolecular halogen bonding.

Repetitive transcranial magnetic stimulation improves consciousness in some patients with disorders of consciousness.

OBJECTIVE: To investigate the therapeutic efficacy of repetitive transcranial magnetic stimulation (rTMS) in patients with disorders of consciousness. DESIGN AND SETTING: We performed a randomized, double-blinded, sham-controlled trial. PARTICIPANTS: Patients (N = 40) with disorders of consciousness. INTERVENTIONS: Forty patients with disorders of consciousness (time since onset of the disorder 49.0 ± 24.6 days) were enrolled and randomized to groups receiving either active-rTMS or sham-rTMS. The active-TMS protocol had a frequency of 20 Hz, was delivered over the left dorsolateral prefrontal cortex and had a 100% rest motor threshold. The sham-rTMS protocol was the same as the active protocol without magnetic stimulation over the cortex. MAIN OUTCOME MEASURES: Consciousness was evaluated by the Coma Recovery Scale-Revised (CRS-R) before and after the four-week intervention. The ratio of patients that awakened from disorders of consciousness was followed up at discharge. RESULTS: Before rTMS sessions, there were no significant differences in consciousness scores between groups. Compared to sham-rTMS (6.25 ± 1.29), patients with disorders of consciousness treated by active rTMS showed strikingly improved consciousness (8.45 ± 3.55). In-depth analysis revealed that only some patients showed obvious increases in consciousness scores induced by active rTMS. Furthermore, rTMS did not significantly enhance the awakening ratio. CONCLUSIONS: rTMS showed therapeutic efficacy for improving consciousness in some, but not all, patients with disorders of consciousness. It is essential to discern the potential patients whose consciousness can be improved by rTMS.

Nearly Unity Quantum Yield Persistent Room-Temperature Phosphorescence from Heavy Atom-Free Rigid Inorganic/Organic Hybrid Frameworks.

Synergism between covalent and non-covalent bonds is employed to fix an organic phosphor guest in a rigid inorganic framework, simulating the stiffening effect seen in the glassy state and realizing efficient and ultralong room-temperature phosphorescence (RTP). Twelve heavy-atom-free composites have been obtained through introducing arylboric or arylcarboxylic acid derivatives into the inorganic boric acid matrix by solid-phase synthesis. Owing to the stiffening effect of multiple bonds, all the composites show highly efficient and persistent RTP of guest molecules with a quantum yield ranging from 39.8 % to ca. 100 % and a lifetime up to 8.74 s, which results in a 55 s afterglow visible to the naked eye after exposure to a portable UV lamp. Interestingly, it is found that the substitution position and quantity of carboxyl in the guest have a great influence on the phosphorescent properties, and that the heavy-atom effect is invalid in such host-guest hybrid systems. The 100 g grade composite is easily prepared because of the solvent-free, green, and simple synthesis method. These results provide an important way for the development of RTP materials with ultrahigh quantum yield and ultralong lifetime, as well as their practical applications in the fields of anti-counterfeiting and information storage, among others.