Lattice matching and halogen regulation for synergistically induced large Li and Na storage by halogenated MXene V3C2Cl2.

Suffering from the formation of metal-ion dendrites and low storage capacity, MXene materials exhibit unsatisfactory performance in Li and Na storage. In this study, we demonstrate that the MXene V3C2Cl2 structure can induce uniform Li and Na deposition. This is achieved through coherent heterogeneous interface reconstruction and regulated ion tiling by halogen surface termination. The high lattice matching (91% and 99%) between MXenes and Li/Na, along with positive Cl terminal regulation, guides Li/Na ions to nucleate uniformly on the V3C2Cl2 MXene matrix and grow in a planar manner. Cl termination proves effective in regulating Li/Na ions due to its moderate adsorption and diffusion coefficients. Furthermore, upon adsorption onto the Cl-terminated V3C2Cl2 monolayer, Li4 and Na4 clusters undergo dissociation, favoring uniform adsorption over cluster adsorption. V3C2Cl2 MXenes exhibit impressive Li/Na storage capacities of 434.07 mA h g-1 for Li and 217.03 mA h g-1 for Na, surpassing the Li storage capacity of Ti3C2Cl2 by three-fold and the Na storage capacity of V2C by 1.4 times. This study highlights the regulatory role of Cl surface terminals in dendrite formation and Li/Na ion deposition, with potential applications to other metal-ion storage electrodes.

Vascular endothelial growth factor promotes transdifferentiation of astrocytes into neurons via activation of the MAPK/Erk-Pax6 signal pathway.

Reactive astrocytes can be transformed into new neurons. Vascular endothelial growth factor (VEGF) promotes the transformation of reactive astrocytes into neurons in ischemic brain. Therefore, in this study, the molecular mechanism of VEGF's effect on ischemia/hypoxia-induced astrocyte to neuron transformation was investigated in the models of rat middle cerebral artery occlusion (MCAO) and in astrocyte culture with oxygen and glucose deprivation (OGD). We found that VEGF enhanced ischemia-induced Pax6, a neurogenic fate determinant, expression and Erk phosphorylation in reactive astrocytes and reduced infarct volume of rat brain at 3 days after MCAO, which effects could be blocked by administration of U0126, a MAPK/Erk inhibitor. In cultured astrocytes, VEGF also enhanced OGD-induced Erk phosphorylation and Pax6 expression, which was blocked by U0126, but not wortmannin, a PI3K/Akt inhibitor, or SB203580, a MAPK/p38 inhibitor, suggesting VEGF enhanced Pax6 expression via activation of MAPK/Erk pathway. OGD induced the increase of miR365 and VEGF inhibited the increase of OGD-induced miR365 expression. However, miR365 agonists blocked VEGF-enhanced Pax6 expression in hypoxic astrocytes, but did not block VEGF-enhanced Erk phosphorylation. We further found that VEGF promoted OGD-induced astrocyte-converted to neuron. Interestingly, both U0126 and Pax6 RNAi significantly reduced enhancement of VEGF on astrocytes-to-neurons transformation, as indicated Dcx and MAP2 immunopositive signals in reactive astrocytes. Moreover, those transformed neurons become mature and functional. We concluded that VEGF enhanced astrocytic neurogenesis via the MAPK/Erk-miR-365-Pax6 signal axis. The results also indicated that astrocytes play important roles in the reconstruction of neurovascular units in brain after stroke.

Grape bunches of novel conjugated chain bonded fullerene oligomers: design of a potential electron trap carbonaceous molecular material.

Developing π electron conjugated groups as covalent bonded bridges between fullerenes in their oligomers is key to optimizing and maximizing functions of the fullerene-based materials. In this work, a series of novel conjugated chain bonded fullerene C60 oligomers (CBFOs) with a well-defined nano-architecture and "grape bunches" shapes are rationally designed and viably constructed based on fullerene-carbenes by means of DFT calculations. The results show that the presently designed CBFOs present a much better electron-accepting ability together with a much lower reorganization energy than the isolated fullerene C60, and characterized as the potential ideal candidate for electron acceptors. The frontier molecular orbital and electron density analysis can well support the results of diabatic electron affinity (EAa) and vertical electron affinity (EAv) calculations. Moreover, these CBFOs exhibit strong absorption in the visible region but no obvious absorption in the ultraviolet region. In addition, the optical properties of the CBFOs and two dimensional structure are also simulated and explored theoretically. We hope that the present study would be helpful for developing covalent-bonded-fullerene based electron trap molecular materials, building blocks of nano-devices and nano-machinery applications.

Symmetry-breaking-induced ferroelectric HfSnX3 monolayers and their tunable Janus structures: promising candidates for photocatalysts and nanoelectronics.

Designing novel two-dimensional (2D) ferroelectric materials by symmetry breaking and studying their mechanisms play important roles in the discovery of new ferroelectric photocatalysts and nanoelectronics. In this study, we have systematically investigated a series of novel ferroelectric 2D HfSnX3 (X = S, Se and Te) monolayers through first-principles calculations. We found that each HfSnX3 monolayer contains a stable ferroelectric phase (FP) and a paraelectric phase (PP). The large polarization (up to 1.64 µC cm-2) in the FP can significantly bend the oxidation reduction potential of water, making HfSnX3 monolayers become excellent ferroelectric photocatalysts. Specifically, by designing a Janus structure to break the symmetry of the PP, we have excitingly obtained a stable Hf2GeSnSe6 (referred to as HGSS) monolayer with triple polarized states. HGSS not only possesses great visible light absorption properties (about 3 × 105 cm-1) as photocatalysts but also successfully solves the dead layer problem previously reported in practical applications. In addition, by constructing a heterostructure with graphene, HGSS has great application in the design of controllable ultrathin p-n junctions. Overall, our study not only predicts a series of potential ferroelectric photocatalytic materials, but also provides valuable insights for designing tunable polarized materials and nanoelectronics.

Priority Occupation of C-Sites by N-Confining P-Implantation in Pyrrodic N-Sites in NCNT@P,N-Mo2C for Highly Efficient Electrocatalytic Hydrogen Evolution.

Optimizing the electronic configuration of Mo2C by activating heteroatom(s)-neighboring carbon atoms to enhance the activity of hydrogen evolution reaction (HER) has been demonstrated. However, the development of heteroatom-doped Mo2C to fabricate a water electrolyzer is still a challenge because of the limitation of a well-defined electronic structure of hybridization of Mo with heteroatom(s). Here, nitrogen (N) and phosphor (P) codoped Mo2C embedded carbon nanotubes (NCNT@P,N-Mo2C) with the priority occupation of C-sites by N, which well confines the P-implantation at the pyrrodic N-sites and brings out N-O bonding on the surface, which favorably modifies the electronic configuration of adjacent Mo, resulting in highly efficient pH-tolerant HER activity. This study not only presents a potential HER electrocatalyst candidate but also provides a strategy for the construction of a well-defined electronic structure of heteroatom(s)-neighboring carbon-based materials.

Electronic and optical properties of a novel two-dimensional semiconductor material TlPt2S3: a first-principles study.

Two-dimensional (2D) materials have attracted widespread attention due to their unique physical and chemical properties. Here, by using density functional theory calculations, we suggest a novel 2D TlPt2S3 material whose layered bulk counterpart was synthesized in 1973. Theoretical calculation results indicate that the exfoliating energy of monolayer and bilayer TlPt2S3 is 34.96 meV Å-2 and 36.03 meV Å-2. We systematically studied the electronic and optical properties of monolayer and bilayer TlPt2S3, and revealed that they are indirect band gap semiconductors with band gaps of 2.26 eV and 2.10 eV, respectively. Monolayer and bilayer TlPt2S3 exhibit superior carrier mobility (901.63 cm2 V-1 s-1 and 13635.04 cm2 V-1 s-1 for electron mobility of the monolayer and bilayer, respectively) and photocatalytic performance (as high as 1 × 105 light absorption coefficient in the visible light region). Interestingly, we find that monolayer TlPt2S3 has significant hydrogen evolution performance, while in the bilayer, the electron band distribution shows complete oxygen evolution ability, which indicates that the proposed monolayer and bilayer TlPt2S3 are potential novel 2D materials suitable for photocatalytic water splitting driven by visible light.

Intrinsic Analysis of Thermally Activated Delayed Fluorescence (TADF) for Ag(I) Complex Based on the Path Integral Approach: Origin of the Effective Spin-Flipping Channel and Vibrational Spin-Orbit Coupling Effect.

In order to design new Ag(I)-based materials for thermally activated delayed fluorescence (TADF), it is vital to develop a detailed understanding of the current best performing materials. The quantitative predictions of the photophysical processes of the Ag(dmp)(P2-nCB) TADF complex are calculated using time-dependent density functional theory (TD-DFT) combined with the path integral approach for dynamics including the Herzberg-Teller effects. All calculated results are in good agreement with the experimentally available data, demonstrating the validity of our applied theoretical approach. Analysis of ETS-NOCV (extended transition state natural orbital for chemical valence) shows that there is a weak bond interaction dominated by electrostatic interactions and accompanied by some covalent components between Ag(I) and dmp ligands due to the introduction of the strongly electron-donating negatively charged P2-nCB ligand, thus giving a small energy separation between the lowest singlet S1 and triplet T1 states of ΔE(S1 - T1) ≈ 532 cm-1. The SOC strongly depends on the geometrical alteration caused by the molecular "promotion" vibrations. Our study has revealed that a few "promotion" vibrational modes, that is, ω46 and ω227, effectively induce the strong SOC between S1 and T1 and speed up the reverse intersystem crossing (RISC) process dramatically. The computed kRISC value is 1.19 × 107 s-1 for the solid phase at 300 K, which are about 5 orders of magnitude larger than the mean phosphorescence rate, kP = 9.56 × 102 s-1, and it is also far larger than ISC k0ISC = 7.84 × 102 s-1 rates from T1 to S0. The S1 state thus can be an efficient thermal repopulation from the T1 state by the RISC pathway. Finally, we also note that the diabatic vibration coupling triplet pair T1/T2 will also be important for efficient and practical RISC. Our investigation will be of great utility toward designing and improving the Ag(I)-based TADF complexes.

Artificial selection on GmOLEO1 contributes to the increase in seed oil during soybean domestication.

Increasing seed oil content is one of the most important breeding goals for soybean due to a high global demand for edible vegetable oil. However, genetic improvement of seed oil content has been difficult in soybean because of the complexity of oil metabolism. Determining the major variants and molecular mechanisms conferring oil accumulation is critical for substantial oil enhancement in soybean and other oilseed crops. In this study, we evaluated the seed oil contents of 219 diverse soybean accessions across six different environments and dissected the underlying mechanism using a high-resolution genome-wide association study (GWAS). An environmentally stable quantitative trait locus (QTL), GqOil20, significantly associated with oil content was identified, accounting for 23.70% of the total phenotypic variance of seed oil across multiple environments. Haplotype and expression analyses indicate that an oleosin protein-encoding gene (GmOLEO1), colocated with a leading single nucleotide polymorphism (SNP) from the GWAS, was significantly correlated with seed oil content. GmOLEO1 is predominantly expressed during seed maturation, and GmOLEO1 is localized to accumulated oil bodies (OBs) in maturing seeds. Overexpression of GmOLEO1 significantly enriched smaller OBs and increased seed oil content by 10.6% compared with those of control seeds. A time-course transcriptomics analysis between transgenic and control soybeans indicated that GmOLEO1 positively enhanced oil accumulation by affecting triacylglycerol metabolism. Our results also showed that strong artificial selection had occurred in the promoter region of GmOLEO1, which resulted in its high expression in cultivated soybean relative to wild soybean, leading to increased seed oil accumulation. The GmOLEO1 locus may serve as a direct target for both genetic engineering and selection for soybean oil improvement.

A TIR-NBS-LRR Gene MdTNL1 Regulates Resistance to Glomerella Leaf Spot in Apple.

Glomerella leaf spot (GLS), caused by the fungus Colletotrichum fructicola, is one of the most devastating apple diseases. Our previous study reported that the GLS resistance locus was defined on the chromosome 15 region. Here, we further found a single-nucleotide polymorphism (SNP) site (SNP7309212) in the GLS resistance that was able to distinguish resistant cultivars (lines) from susceptible ones. On the basis of the SNP site, we cloned a TNL gene from the GLS resistant locus and named it MdTNL1 (NCBI Accession Number: ON402514). This gene contains a toll/interleukin-1 receptor transmembrane domain (TIR), nucleotide-binding sites (NBS), and leucine-rich repeat (LRR) domain. Subcellular location indicated that MdTNL1 was expressed in the nucleus and cell membrane. Ectopic overexpression of MdTNL1 in Nicotiana benthamiana caused cell death. We further demonstrated allelic polymorphisms in MdTNL1. It is noteworthy that NBS and LRR domains of the MdTNL1 protein serve as the repository for generating allelic diversity. Quantitative real-time PCR (qRT-PCR) assay revealed that MdTNL1 was highly expressed in resistant apple cultivar 'Fuji' after inoculation with C. fructicola, whereas susceptible cultivar 'Golden Delicious' exhibited low expression after inoculation. Over-expression of MdTNL1-1 in susceptible apple fruits and leaves improved disease resistance, while in 'Orin' calli, silencing the MdTNL1-1 gene conversely decreased GLS resistance. In conclusion, we identified a GLS associated with SNP7309212 and demonstrated that a TIR-NBS-LRR gene MdTNL1-1 positively regulates GLS resistance in apple.

Molecular chaperones and Parkinson's disease.

Parkinson's disease (PD) is a neurodegenerative disease characterized by progressive death of dopaminergic neurons in the substantia nigra and the formation of Lewy bodies (LBs). Mutations in PD-related genes lead to neuronal pathogenesis through various mechanisms, with known examples including SNCA/α-synuclein (PAKR1), Parkin (PARK2), PINK1 (PARK6), DJ-1 (PARK7), and LRRK2 (PARK8). Molecular chaperones/co-chaperones are proteins that aid the folding of other proteins into a functionally active conformation. It has been demonstrated that chaperones/co-chaperones interact with PD-related proteins and regulate their function in PD. HSP70, HSP90 and small heat shock proteins can prevent neurodegeneration by regulating α-syn misfolding, oligomerization and aggregation. The function of chaperones is regulated by co-chaperones such as HSP110, HSP40, HOP, CHIP, and BAG family proteins. Parkin, PINK1 and DJ-1 are PD-related proteins which are associated with mitochondrial function. Molecular chaperones regulate mitochondrial function and protein homeostasis by interacting with these PD-related proteins. This review discusses critical molecular chaperones/co-chaperones and PD-related proteins which contribute to the pathogenesis of PD, hoping to provide new molecular targets for therapeutic interventions to thwart the disease progression instead of only bringing symptomatic relief. Moreover, appreciating the critical role of chaperones in PD can also help us screen efficient biomarkers to identify PD at an early stage.

Insights from QM/MM-ONIOM calculations: the TADF phenomenon of phenanthro[9,10-d]imidazole-anthraquinone in the solid state.

In this paper, we employed first-principles methods and the QM/MM technique to study the thermally activated delayed fluorescence (TADF) phenomenon of a near-infrared molecule (PIPAQ) in vacuum, solution, and the aggregation state. Our calculated results show that (1) the cluster can decrease the energy gap between the first singlet excited state (S1) and the first triplet state (T1) compared with the monomer, furthermore, the T1 state and S1 state in the cluster are energetically closer to each other, which implies that the energy gap is smaller in comparison with that in solution and can promote the intersystem crossing (ISC) process due to the surrounding effect; (2) the optimally tuned range-separated functional is applicable to simulation of excited states and the outcomes are in good agreement with experimental values; (3) the reorganization energies associated with ISC and the reverse intersystem crossing (RISC) processes between the S1 and T1 states are sensitive to the calculated methods and the environments, and thus the following calculated ISC and RISC rates vary dramatically according to different reorganization energies; (4) all radiative and nonradiative rates are insensitive to temperature, but sensitive to environments, all the radiative rates increase in the cluster while the nonradiative rates decrease, which enhances the fluorescence quantum efficiency and agrees with the observed value. The above results demonstrate that the surrounding effects are very important for modulating the photophysical properties of the PIPAQ compound. Finally, this studied conclusion can give a helpful insight into the TADF mechanism for the title compounds, by which novel TADF materials with excellent performance could be rationally designed.

Up-regulating GmETO1 improves phosphorus uptake and use efficiency by promoting root growth in soybean.

Soybean is a high inorganic phosphate (Pi) demanding crop; its production is strongly suppressed when Pi is deficient in soil. However, the regulatory mechanism of Pi deficiency tolerance in soybean is still largely unclear. Here, our findings highlighted the pivotal role of the ethylene-associated pathway in soybean tolerance to Pi deficiency by comparatively studying transcriptome changes between a representative Pi-deficiency-tolerant soybean genotype NN94156 and a sensitive genotype Bogao under different Pi supplies. By further integrating high-confident linkage and association mapping, we identified that Ethylene-Overproduction Protein 1 (GmETO1), an essential ethylene-biosynthesis regulator, underlies the major quantitative trait locus (QTL) q14-2 controlling Pi uptake. GmETO1 was also the representative member of ETO1 family members that was strongly induced by Pi deficiency. Overexpressing GmETO1 significantly enhanced Pi deficiency tolerance by increasing proliferation and elongation of hairy roots, Pi uptake and use efficiency, and conversely, silencing of GmETO1 led to opposite findings. We further demonstrated that Pi-deficiency inducible genes critical for root morphological and physiological traits including GmACP1/2, Pht1;4, Expansin-A7 and Root Primordium Defective 1 functioned downstream of GmETO1. Our study provides comprehensive insight into the complex regulatory mechanism of Pi deficiency tolerance in soybean and a potential way to genetically improve soybean low-Pi tolerance.

Electronic coupling and spin-orbit charge transfer intersystem crossing (SOCT-ISC) in compact BDP-carbazole dyads with different mutual orientations of the electron donor and acceptor.

In order to study the spin-orbit charge transfer induced intersystem crossing (SOCT-ISC), Bodipy (BDP)-carbazole (Cz) compact electron donor/acceptor dyads were prepared. Charge transfer (CT) emission bands were observed for dyads showing strong electronic coupling between the donor and the acceptor (coupling matrix elements VDA, 0.06 eV-0.18 eV). Depending on the coupling magnitude, the CT state of the dyads can be either dark or emissive. Equilibrium between the 1LE (locally excited) state and the 1CT state was confirmed by temperature-dependent fluorescence studies. Efficient ISC was observed for the dyads with Cz connected at the meso-position of the BDP. Interestingly, the dyad with non-orthogonal geometry shows the highest ISC efficiency (ΦΔ = 58%), which is different from the previous conclusion. The photo-induced charge separation (CS, time constant: 0.7 ps) and charge recombination (CR, ∼3.9 ns) were studied by femtosecond transient absorption spectroscopy. Nanosecond transient absorption spectroscopy indicated that the BDP-localized triplet state was exceptionally long-lived (602 µs). Using pulsed laser excited time-resolved electron paramagnetic resonance spectroscopy, the SOCT-ISC mechanism was confirmed, and we show that the electron spin polarization of the triplet state is highly dependent on the mutual orientation of the donor and acceptor. The dyads were used as triplet photosensitizers for triplet-triplet-annihilation (TTA) upconversion, and the quantum yield is up to 6.7%. TTA-based delayed fluorescence was observed for the dyads (τDF = 41.5 µs). The dyads were also used as potent photodynamic therapy reagents (light toxicity of IC50 = 0.1 µM and dark toxicity of IC50 = 70.8 µM).

Genome-Wide Analysis Reveals Dynamic Epigenomic Differences in Soybean Response to Low-Phosphorus Stress.

Low-phosphorus (low-P) stress has a significant limiting effect on crop yield and quality. Although the molecular mechanisms of the transcriptional level responsible for the low-P stress response have been studied in detail, the underlying epigenetic mechanisms in gene regulation remain largely unknown. In this study, we evaluated the changes in DNA methylation, gene expression and small interfering RNAs (siRNAs) abundance genome-wide in response to low-P stress in two representative soybean genotypes with different P-efficiencies. The DNA methylation levels were slightly higher under low-P stress in both genotypes. Integrative methylation and transcription analysis suggested a complex regulatory relationship between DNA methylation and gene expression that may be associated with the type, region, and extent of methylation. Association analysis of low-P-induced differential methylation and gene expression showed that transcriptional alterations of a small part of genes were associated with methylation changes. Dynamic methylation alterations in transposable element (TE) regions in the CHH methylation context correspond with changes in the amount of siRNA under low-P conditions, indicating an important role of siRNAs in modulating TE activity by guiding CHH methylation in TE regions. Together, these results could help to elucidate the epigenetic regulation mechanisms governing the responses of plants to abiotic stresses.

Vascular endothelial growth factor increases the function of calcium-impermeable AMPA receptor GluA2 subunit in astrocytes via activation of protein kinase C signaling pathway.

Astrocytic calcium signaling plays pivotal roles in the maintenance of neural functions and neurovascular coupling in the brain. Vascular endothelial growth factor (VEGF), an original biological substance of vessels, regulates the movement of calcium and potassium ions across neuronal membrane. In this study, we investigated whether and how VEGF regulates glutamate-induced calcium influx in astrocytes. We used cultured astrocytes combined with living cell imaging to detect the calcium influx induced by glutamate. We found that VEGF quickly inhibited the glutamate/hypoxia-induced calcium influx, which was blocked by an AMPA receptor antagonist CNQX, but not D-AP5 or UBP310, NMDA and kainate receptor antagonist, respectively. VEGF increased phosphorylation of PKCα and AMPA receptor subunit GluA2 in astrocytes, and these effects were diminished by SU1498 or calphostin C, a PKC inhibitor. With the pHluorin assay, we observed that VEGF significantly increased membrane insertion and expression of GluA2, but not GluA1, in astrocytes. Moreover, siRNA-produced knockdown of GluA2 expression in astrocytes reversed the inhibitory effect of VEGF on glutamate-induced calcium influx. Together, our results suggest that VEGF reduces glutamate-induced calcium influx in astrocytes via enhancing PKCα-mediated GluA2 phosphorylation, which in turn promotes the membrane insertion and expression of GluA2 and causes AMPA receptors to switch from calcium-permeable to calcium-impermeable receptors, thereby inhibiting astrocytic calcium influx. The present study reveals that excitatory neurotransmitter glutamate-mediated astrocytic calcium influx can be regulated by vascular biological factor via activation of AMPA receptor GluA2 subunit and uncovers a novel coupling mechanism between astrocytes and endothelial cells within the neurovascular unit.

Endothelial cells promote excitatory synaptogenesis and improve ischemia-induced motor deficits in neonatal mice.

Brain microvascular endothelial cells (BMEC) are highly complex regulatory cells that communicate with other cells in the neurovascular unit. Cerebral ischemic injury is known to produce detectable synaptic dysfunction. This study aims to investigate whether endothelial cells in the brain regulate postnatal synaptic development and to elucidate their role in functional recovery after ischemia. Here, we found that in vivo engraftment of endothelial cells increased synaptic puncta and excitatory postsynaptic currents in layers 2/3 of the motor cortex. This pro-synaptogenic effect was blocked by the depletion of VEGF in the grafted BMEC. The in vitro results showed that BMEC conditioned medium enhanced spine and synapse formation but conditioned medium without VEGF had no such effects. Moreover, under pathological conditions, transplanted endothelial cells were capable of enhancing angiogenesis and synaptogenesis and improved motor function in the ischemic injury model. Collectively, our findings suggest that endothelial cells promote excitatory synaptogenesis via the paracrine factor VEGF during postnatal development and exert repair functions in hypoxia-ischemic neonatal mice. This study highlights the importance of the endothelium-neuron interaction not only in regulating neuronal development but also in maintaining healthy brain function.

Investigation of Conversion and Decay Processes in Thermally Activated Delayed Fluorescence Copper(I) Molecular Crystal: Theoretical Estimations from an ONIOM Approach Combined with the Tuned Range-Separated Density Functional Theory.

Accurate research of the photophysical processes is of great significance for the rational design of excellent thermally activated delayed fluorescence (TADF) materials. Herein, the interconversion and decay rates of the first excited singlet state (S1) and triplet states (T1) in the Cu(pop)(pz2BH2) complex are computed using the thermal vibration correlation function (TVCF) theory at different temperature. For consideration of the solid-state environment, a methodology that is based on the ONIOM model, combined with the optimally tuned range-separated hybrid functional (CAM-B3LYP*) method, was applied. Our calculated results are in excellent agreement with the experimentally available data. It has been found that the energy dissipation of the nonradiative processes from the S1 to ground state is promoted by low frequency vibrational modes in the solution phase, resulting in the high knr(S) = 1.68 × 108 s-1 at 300 K. However, for the crystal phase, they are easily hindered through intermolecular interactions, knr(S) is predicted to be decreased by about 5 orders of magnitude upon aggregation (2.98 × 103 s-1). With temperature increase, the reverse intersystem crossing (RISC) rate kRISC from T1 to S1 is drastically increased to 6.12 × 104 s-1 at 300 K, while the change of other rates is still small, which can compete with the radiative decay rate of kr(T) = 4.75 × 104 s-1 and nonradiative intersystem crossing rate of kISC(T1-S0) = 6.63 × 102 s-1 at the T1 state. This implies that the S1 state can be an efficient thermal population from the T1 state, leading to an occurrence of delayed fluorescence, and the complexes exhibit high emission quantum yields, 58.7%. But, at low temperature T < 100 K, the RISC rate is sharply change, kRISC ≪ kr(T) or kISC, which cannot induce an occurrence of delayed fluorescence. Our investigation would be helpful for designing novel, high-efficiency TADF materials.

Basic photophysical analysis of a thermally activated delayed fluorescence copper(i) complex in the solid state: theoretical estimations from a polarizable continuum model (PCM)-tuned range-separated density functional approach.

A quantitative understanding of photophysical processes is fundamental for designing novel thermally activated delayed fluorescence (TADF) materials. Taking a Cu(pop)(pz2Bph2) crystal as a typical TADF molecular model, we computed the conversion and decay rates of the first excited singlet state (S1) and triplet state (T1) at different temperatures by employing the thermal vibration correlation function (TVCF) approach. For the consideration of the solid-state environment, a methodology, which is based on the combination of a nonempirical, optimally tuned range-separated hybrid functional with the polarizable continuum model, was applied. Our calculated results are in excellent agreement with the experimentally available data. It is found that the reverse intersystem crossing (RISC) from T1 to S1 proceeds at a rate of kRISC = 6.34 × 105 s-1 and can compete with the radiative decay rate (k = 3.29 × 103 s-1) and nonradiative intersystem crossing rate (k = 1.48 × 102 s-1) of T1 at 300 K. This implies that the S1 state can be repopulated from the T1 state, TADF should be observed and the TADF decay time was found to be τ (300 K) = 9.68 µs by fitting calculations. In addition, the calculations indicate that the free rotation of the phenylene ring in the pop ligand can provide an important channel to energy conversion between T1 and S1. But, at a low temperature of T < 100 K, the situation will experience a larger change. The RISC rate becomes very small, kRISC ≪ k or kISC, and it cannot induce an occurrence of delayed fluorescence. As a consequence, Cu(pop)(pz2Bph2) is a highly attractive candidate for applications of TADF.

An Intrinsically Disordered Motif Mediates Diverse Actions of Monomeric C-reactive Protein.

Most proinflammatory actions of C-reactive protein (CRP) are only expressed following dissociation of its native pentameric assembly into monomeric form (mCRP). However, little is known about what underlies the greatly enhanced activities of mCRP. Here we show that a single sequence motif, i.e. cholesterol binding sequence (CBS; a.a. 35-47), is responsible for mediating the interactions of mCRP with diverse ligands. The binding of mCRP to lipoprotein component ApoB, to complement component C1q, to extracellular matrix components fibronectin and collagen, to blood coagulation component fibrinogen, and to membrane lipid component cholesterol, are all found to be markedly inhibited by the synthetic CBS peptide but not by other CRP sequences tested. Likewise, mutating CBS in mCRP also greatly impairs these interactions. Functional experiments further reveal that CBS peptide significantly reduces the effects of mCRP on activation of endothelial cells in vitro and on acute induction of IL-6 in mice. The potency and specificity of CBS are critically determined by the N-terminal residues Cys-36, Leu-37, and His-38; while the versatility of CBS appears to originate from its intrinsically disordered conformation polymorphism. Together, these data unexpectedly identify CBS as the major recognition site of mCRP and suggest that this motif may be exploited to tune the proinflammatory actions of mCRP.

Occurrence of Breast Mucinous Carcinoma After Autologous Fat Grating for Breast Augmentation.

UNLABELLED: Autologous fat grafting is commonly performed in reconstructive breast surgery as well as in aesthetic breast augmentation surgery. Nevertheless, little is known about the interaction between fat grafts and cancer. A 36-year-old patient had undergone bilateral breast augmentation with autologous fat grafting. Two months after surgery, she perceived two small palpable indurations in the right breast. Nine months after the procedure, the lumps grew bigger and lumpectomy was performed. Histologic examination of the specimens showed mucinous carcinoma of the breast. This case raises once again the question about the possible links between breast cancer and fat grafts. The level of evidence is level V. NO LEVEL ASSIGNED: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.