Rapid Dissociation Research Articles

Defect-Mediated Exciton Localization and Relaxation in Monolayer MoS2.

Defects in chemical vapor deposition (CVD)-grown monolayer MoS2 are unavoidable and provide a powerful approach to creating single-photon emitters and quantum information systems through localizing excitons. However, insight into the A- trion and B/C exciton localization in monolayer MoS2 remains elusive. Here, we investigate defect-mediated A- trion and B/C exciton localization and relaxation in CVD-grown monolayer MoS2 samples via transient absorption spectroscopy. The localization rate of A- trions is five times faster than B excitons, which is attributed to the distinctions in the Bohr radius, diffusion rate, and multiphonon emission. Furthermore, we obtain unambiguous experimental evidence for the direct excitation of localized C excitons. Varying gap energy at the band-nesting region revealed by first-principles calculations explains the anomalous dependence of localized C exciton energy on delay time. We also find that the rapid dissociation of localized C excitons features a short characteristic time of ∼0.14 ps, while the measured relaxation time is much longer. Our results provide a comprehensive picture of the defect-mediated excitonic relaxation and localization dynamics in monolayer MoS2.

A Novel Self-Assembled Paclitaxel Nanodispersion Facilitates Rapid In-Vitro/In-Vivo Dissociation and Protein Binding.

The study aims to prepare and characterize a novel paclitaxel (PtX) preconcentrate formulation using polymer and lipid excipients that forms nanodispersion upon dilution. The goal was to understand the mechanism of nanodispersion formation and its properties. The water-insoluble PtX was dissolved in organic solvents containing ethanol, polyethylene glycol (PEG400), povidone (PVP), caprylic acid (CA), and sodium cholesterol sulfate (CS). This formulation was diluted in 5% w/v dextrose medium to form PtX nanodispersion, which was assessed for particle size, stability, in-vitro/in-vivo dissociation and protein binding. Transmission electron microscopy (TEM), Small Angle Neutron Scattering (SANS), and Molecular Dynamics (MD) simulations were used to analyse the structure of the nanoparticles. The formulation was a clear, slightly yellow solution. The PtX nanodispersion displays particle size of ~ 100nm with a zeta potential of -25, and the pH of 4.0. It displayed nearly spherical coacervate nanoparticles with a sponge-like structure, lacking internal structure order as revealed by TEM and SANS. MD simulations confirmed self-assembly of PtX and excipients forming nanoparticles. In vitro dissociation studies in simulated plasma demonstrated rapid dissociation of nanodispersion, releasing free PtX that immediately binds to plasma proteins. In vivo studies in rabbits corroborated these findings, showing rapid dissolution. The results present a novel formulation design that forms sponge-like coacervate nanoparticle due to complimentary interactions of the excipients that otherwise are unable to self-assemble under similar conditions of dilution. This alternative formulation solves the limitations of currently marketed PtX products and can provide its effective delivery in clinical settings.

PATH-54. HIGH-THROUGHPUT SINGLE NUCLEAR DNA SEQUENCING OF HUMAN SPORADICNF1 MUTANT IDH-WILDTYPE GLIOBLASTOMAS REVEALS PATTERNS OF TUMOR EVOLUTION AND RECURRENCE

Abstract The advent of single cell techniques has advanced our understanding of glioblastoma (GBM) evolution and cell lineage relationships. However, study of mutational co-occurrence and clonal phylogeny has been hampered by limitations in single cell genotyping. Here, we perform semi-automated, rapid single nuclear dissociation followed by targeted single nucleus DNA sequencing (snDNA-seq) of eleven retrospectively identified somatic NF1 mutant IDH-wildtype glioblastomas. Bulk DNA sequencing was performed as part of routine clinical care using a CLIA-certified targeted sequencing panel. For snDNA-seq, tissue cores with greater than 30% tumor were dissociated on a S2 genomics S100 Singulator followed by snDNA-seq using a targeted 361 amplicon panel (Tapestri, Mission Bio, USA) to sequence for recurrently observed single nucleotide substitutions and copy number alterations. A mean of 3,661 cells were recovered per sample with a mean of 96 reads per cell per amplicon and 87% mean panel uniformity. SnDNA-seq validated point mutations and copy number alterations observed in bulk DNA-sequencing and revealed novel alterations and subclonal copy number alterations not detected on bulk analysis. Within individual samples, snDNA-seq based phylogenetic reconstruction identified mutually exclusive patterns of mutation between NF1 and PI3K signaling alterations, suggesting these events may occur in distinct tumor subclones. With regard to copy number alterations (CNAs), snDNA-seq demonstrated intra-tumoral heterogeneity for chromosome 9p loss, chromosome 7 gain, and chromosome 10 monosomy. Subclonal CNA clones not detected by bulk sequencing were identified in 5 samples. Analysis of a matched primary-recurrent tumor pair revealed expansion of a specific mutational clone (loss of 9p, 10p, gains of 1p, 7, 15, and 19q) at recurrence. SnDNA-seq recapitulated bulk DNA sequencing alterations and identified distinct patterns of mutational co-occurrence, CNAs, and tumor evolution over time. Reconstructing GBM phylogeny at single cell resolution has potential translational implications for understanding tumor evolution and treatment resistance.

Engineering Robust Silver-Decorated calcium peroxide Nano-Antibacterial Platforms for chemodynamic enhanced sterilization

Calcium peroxide (CaO2) is commonly used as a hydrogen peroxide (H2O2) donor to eliminate bacterial infections. However, the rapid dissociation of CaO2 and the explosive release of H2O2 have limited the development of CaO2 in the antibacterial field. Therefore, a series of silver nanoparticles (AgNPs) functionalized bacteria-triggered smart hydrogels (CSA-H) that integrate sustained release of nanoparticles and localized chemodynamic sterilization were constructed. The pH-responsive hydrogel formed through the Schiff base reaction enables the responsive release of CaO2 nanoparticles while simultaneously regulating the concentration of H2O2 within the bacterial infection microenvironment. AgNPs are capable of reacting with H2O2 under mildly acidic conditions to produce hydroxyl radicals with enhanced antimicrobial activity. The antimicrobial results demonstrated that AgNPs functionalized silicon dioxide-coated calcium peroxide (CaO2@SiO2/AgNPs) nanoparticles exhibited enhanced bactericidal activity compared to AgNPs or CaO2 alone. Furthermore, CSA-H hydrogels exhibited significant antibacterial activity against S. aureus and E. coli under the dual effect of AgNPs and pH-driven Fenton-like reactions. This chemodynamic antibacterial platform is environmentally responsive and provides a promising strategy for creating multifunctional hydrogels loaded with nano-enzymes, thus advancing the development of AgNPs in chemodynamic-antibacterial related applications.

Enhanced leaching control of chromium, antimony, and chlorine utilizing CO2-curing slag-fly ash-based agent

This study strives to address the technical bottleneck posed by leaching risks associated with Cr, Sb, and soluble Cl in low-carbon slag-fly ash-based cementitious materials (BFCM) according to our previous research. The introduction of CO2 activation significantly enhances the dissociation of BFS, leading to superior mechanical performance and environmental safety of BFCM. LT3 matrix of BFCM (BFS: MSWI fly ash: FGDG: cement= 42: 20: 10: 28) showed excellent compressive strength (46.79Mpa at 7d). The LT3 matrix enables effective solidification/stabilization (S/S) of Cr, Sb, and Cl with CO2-curing (7d). Furthermore, the leaching concentrations of Sb and Cl within LT system, exhibit a positive correlation, while they demonstrate a negative correlation with Cr. Sb primarily relies on the levels of Ca2+ and OH- in the leaching solution, critical for the formation and stability of Ca-Sb precipitation based Visual MINTEQ fitting. CO2-curing enhances the S/S efficiency of Cl by accelerating the ion exchange of Cl- with OH- in C-A-H and SO42- in the AFm phase, leading to the formation of functional Friedel’s salt. This process is characterized by OH- dissolution and subsequent CaSO4 crystallization. The LT system activated by CO2 exhibited accelerated reaction kinetics relative to traditional hydration (LH), characterized by rapid BFS dissociation and the formation of functional hydration products such as ettringite, C-(A)-S-H, and Friedel's salt. This process also reduced macropores and capillary pores of BFCM, a positive correlation exists between the relative macropore content and Cl leaching levels, whereas the decrease in both macropores and capillary pores is associated with ettringite crystallization.

Unveiling the Dual Role of Oxophilic Cr4+ in Cr-Cu2O Nanosheet Arrays for Enhanced Nitrate Electroreduction to Ammonia.

Cuprous oxide (Cu2O)-based catalysts present a promising activity for the electrochemical nitrate (NO3 -) reduction to ammonia (eNO3RA), but the electrochemical instability of Cu+ species may lead to an unsatisfactory durability, hindering the exploration of the structure-performance relationship. Herein, we propose an efficient strategy to stabilize Cu+ through the incorporation of Cr4+ into the Cu2O matrix to construct a Cr4+-O-Cu+ network structure. In situ and quasi-in situ characterizations reveal that the Cu+ species are well maintained via the strong Cr4+-O-Cu+ interaction that inhibits the leaching of lattice oxygen. Importantly, in situ generated Cr3+-O-Cu+ from Cr4+-O-Cu+ is identified as a dual-active site for eNO3RA, wherein the Cu+ sites are responsible for the activation of N-containing intermediates, while the assisting Cr3+ centers serve as the electron-proton mediators for rapid water dissociation. Theoretical investigations further demonstrated that the metastable state Cr3+-O-Cu+ favors the conversion from the endoergic hydrogenation of the key *ON intermediate to an exoergic reaction in an ONH pathway, and facilitates the subsequent NH3 desorption with a low energy barrier. The superior eNO3RA with a maximum 91.6 % Faradaic efficiency could also be coupled with anodic sulfion oxidation to achieve concurrent NH3 production and sulfur recovery with reduced energy input.

Unveiling the Dual Role of Oxophilic Cr4+ in Cr‐Cu2O Nanosheet Arrays for Enhanced Nitrate Electroreduction to Ammonia

Cuprous oxide (Cu2O)‐based catalysts present a promising activity for the electrochemical nitrate (NO3‐) reduction to ammonia (eNO3RA), but the electrochemical instability of Cu+ species may lead to an unsatisfactory durability, hindering the exploration of the structure‐performance relationship. Herein, we propose an efficient strategy to stabilize Cu+ through the incorporation of Cr4+ into the Cu2O matrix to construct a Cr4+‐O‐Cu+ network structure. In situ and quasi‐in situ characterizations reveal that the Cu+ species are well maintained via the strong Cr4+‐O‐Cu+ interaction that inhibits the leaching of lattice oxygen. Importantly, in situ generated Cr3+‐O‐Cu+ from Cr4+‐O‐Cu+ is identified as a dual‐active site for eNO3RA, wherein the Cu+ sites are responsible for the activation of N‐containing intermediates, while the assisting Cr3+ centers serve as the electron‐proton mediators for rapid water dissociation. Theoretical investigations further demonstrated that the metastable state Cr3+‐O‐Cu+ favors the conversion from the endoergic hydrogenation of the key *ON intermediate to an exoergic reaction in an ONH pathway, and facilitates the subsequent NH3 desorption with a low energy barrier. The superior eNO3RA with a maximum 91.6% Faradaic efficiency could also be coupled with anodic sulfion oxidation to achieve concurrent NH3 production and sulfur recovery with reduced energy input.

Cationic Covalent Organic Framework-Modified Polypropylene Separator for High-Performance Lithium Metal Batteries.

As an important component of lithium batteries, the wettability and thermal stability of the separator play a significant role in cell performance. Despite the availability of numerous commercial separators, issues such as low ion selectivity and poor thermal stability continue to limit the efficiency and reliability of the batteries. Herein, two cationic covalent organic frameworks (Br-COF and TFSI-COF) with abundant imidazole cationic groups were designed to modify commercial polypropylene (PP) separators. The strong lithium-ion affinity of the cationic COF enables the effective dissociation of lithium salt ion clusters, simplifying the solvent structure of lithium ions to promote lithium ions transport. Additionally, solvent anions can be anchored to the cationic COF by electrostatic interactions, reducing side reactions on the lithium metal anode surface to form a favorable SEI layer, which can effectively inhibit the growth of lithium dendrites. The rapid dissociation of anions in lithium salts with some organic solvents and cationic COFs was revealed by a molecular dynamics simulation. A LiF-rich SEI layer on the lithium metal anode surface was formed, which can speed up Li+ transport at interfaces, leading to consistent lithium deposition and outstanding battery performance. The ordered porous structure of the cationic COF provides interconnected and continuous channels, improving the wettability between the liquid electrolyte and separators, which is conducive to ion transport. When paired with a LiFePO4 cathode and electrolyte (1.0 M LiTFSI in DEC: EC: DMC = 1:1:1), the LiFePO4/TFSI-COF@PP/Li cell demonstrates a prominent cycling capacity of 148.0 mAh g-1 at 0.5 C with a Coulombic efficiency of 98.0% in the first cycle, and the capacity retention is 82.0% after 100 cycles, showing good cycling stability. Thus, this investigation provides inspiration for the expansion of cationic COF-modified separators for next-generation lithium metal batteries.

Fluorinated co-solvent electrolytes enable lithium metal batteries to operate at low temperatures

Enhancing the energy output of batteries in low temperatures is critical to broadening the application areas of advanced electronic devices, which can be accomplished by utilizing high-voltage cathodes to match lithium metal anode, optimizing electrolyte electrochemical windows and forming stable solid electrolyte interphases to provide facile ion-transmission kinetics at low temperature. Herein, we demonstrate a fluorinated ester co-solvent electrolyte, which applies 1 M LiPF6 in an ethyl 4,4,4-trifluoro butyrate/fluoroethylene carbonate (FEC) (4/1 by volume ratio) that jointly satisfies high voltage cathode and lithium metal anode reversibility at required ambient. The performance of the battery is due to the rapid dissociation of Li+ and the formation of a fluorine-rich inorganic electrolyte interface in the fluorinated solvent. Therefore, the fluorinated ester co-solvent electrolyte system can provide 209.9 mAh g−1, 194.8 mAh g−1, and 175.5 mAh g−1 when discharged at room temperature, −20 ℃ and −40 ℃, respectively, those far exceeds the performance of carbonate electrolytes. This work advances the development of low-temperature lithium metal batteries.

The Particle Drifting Effect: A Combined Function of Colloidal and Drug Properties.

The particle drifting effect, where nanosized colloidal drug particles overcome the diffusional resistance of the aqueous boundary layer adjacent to the intestinal wall and increase drug absorption rates, is drawing increasing attention in pharmaceutical research. However, mechanistic understanding and accurate prediction of the particle drifting effect remain lacking. In this study, we systematically evaluated the extent of the particle drifting effect affected by drug and colloidal properties, including the size, number, and type of the moving species using biphasic diffusion experiments combined with computational fluid dynamics simulations and mass transport analyses. The results showed that the particle drifting effect is a sequential reaction of particle dissolution/dissociation in the diffusional boundary layer, followed by absorption of the free drug. Therefore, factors affecting the rate-limiting step, which can be either process or both under different circumstances, alter the particle drifting effect. Experimental results also agree with the theory that the particle dissolution rate is dependent on particle size, concentration, and drug solubility. In addition, rapid bile micelle dissociation and bile salt absorption facilitated drug absorption by the particle drifting effect. Our findings explain the highly dynamic nature of the particle drifting effect and will contribute to rational formulation development and better bioavailability prediction for formulations containing colloidal particles.

Synthesis and characterization of a chiral spirobifluorene cyclic hexamer

Abstract A new chiral macrocycle 1-[6], consisting of six chiral spirobifluorene units linked in a cyclic arrangement, was successfully synthesized via a homo-coupling of the corresponding acyclic trimer. Notably, this chiral cyclic hexamer exhibited flexibility in solution, and both low-temperature nuclear magnetic resonance (NMR) experiments and density functional theory (DFT) calculations suggest that its stable structure is not the hexagonal D6-symmetric structure but rather the figure-eight-shaped D2-symmetric structure. In this D2-symmetric structure, the opposing bifluorenyl units are π-stacked, and it is suggested that this π-stacked region undergoes rapid dissociation and reformation at room temperature. The HOMO is distributed over the π-stacked region, with a HOMO-LUMO gap of 4.02 eV. The macrocycle exhibited strong violet fluorescence. The absorption dissymmetry factor |gabs| was 7.4 × 10−3, which is larger compared to the series of chiral smaller macrocycles 1-[n] (n = 3 to 5). Additionally, the CPL efficiency, indicated by a BCPL value of 189 M−1 cm−1, is relatively high among chiral organic luminescent molecules.

Thermostable Nucleoid Protein Cren7 Slides Along DNA and Rapidly Dissociates From DNA While Not Inhibiting the Sliding of Other DNA-binding Protein

A nucleoid protein Cren7 compacts DNA, contributing to the living of Crenarchaeum in high temperature environment. In this study, we investigated the dynamic behavior of Cren7 on DNA and its functional relation using single-molecule fluorescence microscopy. We found two mobility modes of Cren7, sliding along DNA and pausing on it, and the rapid dissociation kinetics from DNA. The salt dependence analysis suggests a sliding with continuous contact to DNA, rather than hopping/jumping. The mutational analysis demonstrates that Cren7 slides along DNA while Trp (W26) residue interacts with the DNA. Furthermore, Cren7 does not impede the target search by a model transcription factor p53, implying no significant interference to other DNA-binding proteins on DNA. At high concentration of Cren7, the molecules form large clusters on DNA via bridging, which compacts DNA. We discuss how the dynamic behavior of Cren7 on DNA enables DNA-compaction and protein-bypass functions.

Decomposition of CH3NH2${\rm CH}_3{\rm NH}_2$: Implications for CHx/NHy${\rm CH}_{\rm {\it x}}/{\rm NH}_{\rm {\it y}}$ radical–radical reactions

AbstractExperiments on methylamine () decomposition in shock tubes, flow reactors, and batch reactors have been re‐examined to improve the understanding of hydrocarbon/amine interactions and constrain rate constants for + reactions. In high‐temperature shock tube experiments, the rapid thermal dissociation of provides a fairly clean source of and radicals, allowing an assessment of reactions of with and NH. At the lower temperatures in batch and flow reactors, is mostly consumed by reaction with H to form + ; these results are useful in determining the fate of the radical. Interpretation of these data, along with flow reactor data for the /H system at lower temperature, indicates that at temperatures up to about 1400 K at atmospheric pressure and above 2000 K at 100 atm, the + reaction forms mainly methylamine. At sufficiently high temperature, H‐abstraction to form + NH and addition–elimination to form + H become competitive. The + NH reaction, with a rate constant close to collision frequency, forms + H, also leading into the hydrocarbon amine pool. Thus, methylamine can be expected to be an important intermediate in co‐combustion of natural gas and ammonia, and more work on the chemistry of is desirable.

ROS-Responsive and Self-Catalytic Nanocarriers for a Combination of Chemotherapy and Reinforced Ferroptosis against Breast Cancer.

Ferroptosis is an appealing cancer therapy strategy based on the H2O2-involved Fenton reaction to produce toxic •OH for lipid peroxidation. However, intracellular H2O2 is easily consumed and results in a deficient Fenton reaction. This obstacle can be overcome by traditional chemotherapeutic drugs for H2O2 supplements. Moreover, a recent work illustrated that dihydroartemisinin (DHA) could promote ferroptosis against tumoral cells, particularly in the presence of ferrous compounds. To achieve combined chemotherapy and ferroptosis, a nanocarrier (TKNPDHA-Fc) was constructed by using thioketal (TK)-bridged paclitaxel prodrug (PEG-TK-PTX) and ferrocene (Fc)-conjugated PEG-Fc, where DHA was encapsulated by a hydrophobic-hydrophobic interaction. Upon cellular uptake, TKNPDHA-Fc could facilitate PTX release through TK breakage under an excess H2O2 microenvironment. Owing to the loss of the hydrophobic PTX component, TKNPDHA-Fc underwent a rapid dissociation for improving DHA to act as a ferroptotic inducer along with Fe supplied from Fc. Moreover, both the chemotherapy-induced reactive oxygen species and the •OH produced from reinforced ferroptosis further stimulated the TK cleavage. The "self-catalytic" loop of TKNPDHA-Fc remarkably improved the antitumor performance in vivo via combined mechanisms, and its tumor inhibition rate reached 78.3%. This work highlights the contribution of ROS-responsive and self-catalytic nanoplatforms for enhancing the potential of combined chemotherapy and ferroptosis for cancer therapy in the future.

Dissoziative Elektronenanlagerungsdynamik eines vielversprechenden Krebsmedikaments zeigt sein Potential als Radiosensitizer

Abstract2‐Bromo‐1‐(3,3‐dinitroazetidin‐1‐yl)ethan‐1‐on (RRx‐001) ist ein Chemotherapeutikum für sauerstoffarme Tumore und zeigte bereits Synergieeffekte in Kombination mit Strahlentherapie. Die Wechselwirkung des Moleküls mit niederenergetischen Sekundärelektronen, die in großer Zahl in der physikalisch‐chemischen Phase der Bestrahlung gebildet werden, könnten für diesen Synergieeffekt verantwortlich sein. Die vorliegende Studie konzentriert sich auf die ersten Schritte in der Wechselwirkung von RRx‐001 mit niederenergetischen Elektronen, in denen das temporäre negative Ion gebildet wird und rasch fragmentiert. Die Kombination von Resultaten zweier Versuchsaufbauten erlaubt es uns, den Zerfall des RRx‐001 Anions auf verschiedenen Zeitskalen zu entflechten. Die alleinige Anwesenheit des eingefangenen Elektrons führt zu einer raschen Abspaltung von NO2 und HNO2, während NO2− und Br− Anionen direkt beziehungsweise über andere Zwischenprodukte gebildet werden. Auf Basis quantenchemischer Rechnungen schlagen wir einen bidirektionalen Wechsel zwischen π*(NO2) und σ*(C−Br) Zuständen vor, welcher die experimentellen Spektren erklärt. Die beobachtete schnelle Dynamik lässt auch Schlussfolgerungen für die Chemie des Anions in der kondensierten Phase zu.

Dissociation of Human and Mouse Tumor Tissue Samples for Single-cell RNA Sequencing.

Human tumor samples hold a plethora of information about their microenvironment and immune repertoire. Effective dissociation of human tissue samples into viable cell suspensions is a required input for the single-cell RNA sequencing (scRNAseq) pipeline. Unlike bulk RNA sequencing approaches, scRNAseq enables us to infer the transcriptional heterogeneity in tumor specimens at the single-cell level. Incorporating this approach in recent years has led to many discoveries, such as identifying immune and tumor cellular states and programs associated with clinical responses to immunotherapies and other types of treatments. Moreover, single-cell technologies applied to dissociated tissues can be used to identify accessible chromatin regions T and B cell receptor repertoire, and the expression of proteins, using DNA barcoded antibodies (CITEseq). The viability and quality of the dissociated sample are critical variables when using these technologies, as these can dramatically affect the cross-contamination of single cells with ambient RNA, the quality of the data, and interpretation. Moreover, long dissociation protocols can lead to the elimination of sensitive cell populations and the upregulation of a stress response gene signature. To overcome these limitations, we devised a rapid universal dissociation protocol, which has been validated on multiple types of human and murine tumors. The process begins with mechanical and enzymatic dissociation, followed by filtration, red blood lysis, and live dead enrichment, suitable for samples with a low input of cells (e.g., needle core biopsies). This protocol ensures a clean and viable single-cell suspension paramount to the successful generation of Gel Bead-In Emulsions (GEMs), barcoding, and sequencing.

(Invited) Exciton Dissociation in Mixed-Dimensionality SWCNT-Based Heterojunctions

Quantum-confined semiconductors provide highly tunable optical and electrical properties for a wide variety of emerging applications. Semiconducting single-walled carbon nanotubes (s-SWCNTs) have shown tremendous potential in applications ranging from digital logic, biological imaging, quantum information processing, photovoltaics, and thermoelectric energy harvesting. Energy harvesting applications rely critically upon the creation of tailored interfaces that enable the movement of energetic species (excitons, electrons, holes) in specified directions. In this talk, I will discuss the use of a variety of rationally designed “mixed-dimensionality” heterojunctions between s-SWCNTs and transition metal dichalcogenide (TMDC) monolayers to harvest visible/near-infrared photons and convert these excitations into long-lived charge-separated states. Type-II heterojunctions between s-SWCNTs and TMDCs enable rapid exciton dissociation and microsecond charge-separated state lifetimes. We have developed new TMDC/SWCNT/TMDC trilayer architectures that enable charge transfer cascades for improving charge separation yield and lifetime. These trilayer architectures allow us to probe out-of-plane carrier diffusion in the nanotube layer and the degree to which bound interfacial excitons impact the photophysics in these mixed-dimensionality heterostructures. I will also discuss the methodology by which we attempt to quantify the photoinduced exciton dissociation quantum yields in these nanoscale heterostructures. Using several heterostructure results, we are attempting to narrow in on appropriate ways to quantify the local dielectric constant and exciton size in both the SWCNT and TMDC components, each of which impact the estimated charge carrier yields. Taken together, these studies provide fundamental insights into the links between ground-state thermodynamics and excited-state dynamics for model nanoscale heterojunctions used to harvest solar energy and produce long-lived charge-separated states.

Chlorine-Induced Stress Corrosion Cracking of Single Crystal Superalloys at 550 °C

AbstractThis study has investigated the effect of NaCl and different gaseous environments on the stress corrosion cracking susceptibility of CMSX-4 at 550 °C. The presence of SOx leads to the rapid dissociation of NaCl into Na2SO4 and the release Cl2 and HCl, which then trigger an active oxidation mechanism and stress corrosion cracking. The incubation time for crack initiation at 690 MPa and in the presence of a sulphur containing environment is 10 min. A working hypothesis is that stress corrosion cracking occurs due to the hydrogen released at the oxide/alloy interface when metal chlorides are formed; however, this hypothesis needs to be further explored.

Structural basis of psychedelic LSD recognition at dopamine D1 receptor

Understanding the kinetics of LSD in receptors and subsequent induced signaling is crucial for comprehending both the psychoactive and therapeutic effects of LSD. Despite extensive research on LSD's interactions with serotonin 2A and 2B receptors, its behavior on other targets, including dopamine receptors, has remained elusive. Here, we present cryo-EM structures of LSD/PF6142-bound dopamine D1 receptor (DRD1)-legobody complexes, accompanied by a β-arrestin-mimicking nanobody, NBA3, shedding light on the determinants of G protein coupling versus β-arrestin coupling. Structural analysis unveils a distinctive binding mode of LSD in DRD1, particularly with the ergoline moiety oriented toward TM4. Kinetic investigations uncover an exceptionally rapid dissociation rate of LSD in DRD1, attributed to the flexibility of extracellular loop 2 (ECL2). Moreover, G protein can stabilize ECL2 conformation, leading to a significant slowdown in ligand's dissociation rate. These findings establish a solid foundation for further exploration of G protein-coupled receptor (GPCR) dynamics and their relevance to signal transduction.

Unveiling the enhanced reactivity of NO ozonation on NH4-SAPO-34 zeolite: Ab initio molecular dynamics combined with experimental characteristics

An environmental-friendly NH4-SAPO-34 catalyst, easily obtained via ion exchange, was prepared and tested for its catalytic ozonation activity in NO oxidation under O3-deficient conditions. Characterization results revealed the successful loading of NH4+ on the Brønsted acidity of SAPO-34 after NH4NO3 ion exchange. Surprisingly, the NH4-SAPO-34 zeolite exhibited superior performance in the catalytic ozonation of NO. Ab initio molecular dynamics simulations demonstrated that the facile binding of NO and O3, along with rapid dissociation of the intermediate (NO2 dimer), contributed to the enhanced catalytic performance of NH4-SAPO-34 compared to H-SAPO-34. Additionally, the impact of various ammonium salts on the catalytic activity was investigated, stating clearly the NH4+ coordination in the eight-membered ring windows as the active site. Thus, this study deepens our understanding of the NO ozonation dynamics catalyzed by NH4-SAPO-34 and provides a promising method for synthesizing catalysts without expensive transition metals.