High-level reverse intersystem crossing of charge transfer compounds: to fluoresce or not to fluoresce?

Thermally activated delayed fluorescence (TADF) has been widely applied to electroluminescent materials to take the best advantage of triplet excitons. For some materials, the TADF originates from high-level reverse intersystem crossing (hRISC), and has attracted much attention due to its high efficiency for utilizing the triplet excitons. However, reports concerning the mechanistic studies on the hRISC-TADF process and structure-property correlation are sparse. In this study, we prepared three compounds containing triphenylamine and benzophenone with different substitution positions, o-TPA-BP, m-TPA-BP, and p-TPA-BP, in which only p-TPA-BP displays strong luminescence and hRISC-TADF features. To investigate the mechanism of the substituent-position-dependent hRISC-TADF, ultrafast time-resolved spectroscopy was utilized to observe the deactivation pathways with the assistance of theoretical calculations. The results show that o-TPA-BP will not generate triplet species, and the triplet species for m-TPA-BP will rapidly deactivate. Only p-TPA-BP can transition back to the singlet state from the T2 state effectively and exhibit a large gap between T1 and T2 to favor the hRISC route. These results illustrate how the substitution position affects the ISC and further influences the luminescence properties, which can provide new insights for developing new high-efficiency luminescent materials.

Photosensitizing metal covalent organic framework with fast charge transfer dynamics for efficient CO2 photoreduction.

Designing artificial photocatalysts for CO2 reduction is challenging, mainly due to the intrinsic difficulty of making multiple functional units cooperate efficiently. Herein, three-dimensional metal covalent organic frameworks (3D MCOFs) were employed as an innovative platform to integrate a strong Ru(ii) light-harvesting unit, an active Re(i) catalytic center, and an efficient charge separation configuration for photocatalysis. The photosensitive moiety was precisely stabilized into the covalent skeleton by using a rational-designed Ru(ii) complex as one of the building units, while the Re(i) center was linked via a shared bridging ligand with an Ru(ii) center, opening an effective pathway for their electronic interaction. Remarkably, the as-synthesized MCOF exhibited impressive CO2 photoreduction activity with a CO generation rate as high as 1840 µmol g-1 h-1 and 97.7% selectivity. The femtosecond transient absorption spectroscopy combined with theoretical calculations uncovered the fast charge-transfer dynamics occurring between the photoactive and catalytic centers, providing a comprehensive understanding of the photocatalytic mechanism. This work offers in-depth insight into the design of MCOF-based photocatalysts for solar energy utilization.

Efficient intersystem crossing and tunable ultralong organic room-temperature phosphorescence via doping polyvinylpyrrolidone with polyaromatic hydrocarbons.

Polymer-based pure organic room-temperature phosphorescent materials have tremendous advantages in applications owing to their low cost, vast resources, and easy processability. However, designing polymer-based room-temperature phosphorescent materials with large Stokes shifts as key requirements in biocompatibility and environmental-friendly performance is still challenging. By generating charge transfer states as the gangplank from singlet excited states to triplet states in doped organic molecules, we find a host molecule (pyrrolidone) that affords charge transfer with doped guest molecules, and excellent polymer-based organic room-temperature phosphorescent materials can be easily fabricated when polymerizing the host molecule. By adding polyaromatic hydrocarbon molecules as electron-donor in polyvinylpyrrolidone, efficient intersystem crossing and tunable phosphorescent from green to near-infrared can be achieved, with maximum phosphorescence wavelength and lifetime up to 757 nm and 3850 ms, respectively. These doped polyvinylpyrrolidone materials have good photoactivation properties, recyclability, advanced data encryption, and anti-counterfeiting. This reported design strategy paves the way for the design of polyvinylpyrrolidone-based room-temperature phosphorescent materials.

Multiple Pathways in the Triplet States Population for a Naphthalenediimide-C60 Dyad.

The link of an antenna dye with an electron spin converter, in this case naphthalenediimide and C60, produces a system with a rich photophysics including the detection of more than one triplet state on the long timescale (tens of µs). Beside the use of optical spectroscopies in the ns and in the fs time scale, we used time-resolved Electron Paramagnetic Resonance (TREPR) to study the system evolution following photoexcitation. TREPR keeps track of the formation path of the triplet states through specific spin polarization patterns observed in the spectra. The flexibility of the linker plays a role in favouring either electron transfer or energy transfer processes.

US-based Sequential Algorithm Integrating an AI Model for Advanced Liver Fibrosis Screening.

Background Noninvasive tests can be used to screen patients with chronic liver disease for advanced liver fibrosis; however, the use of single tests may not be adequate. Purpose To construct sequential clinical algorithms that include a US deep learning (DL) model and compare their ability to predict advanced liver fibrosis with that of other noninvasive tests. Materials and Methods This retrospective study included adult patients with a history of chronic liver disease or unexplained abnormal liver function test results who underwent B-mode US of the liver between January 2014 and September 2022 at three health care facilities. A US-based DL network (FIB-Net) was trained on US images to predict whether the shear-wave elastography (SWE) value was 8.7 kPa or higher, indicative of advanced fibrosis. In the internal and external test sets, a two-step algorithm (Two-step#1) using the Fibrosis-4 Index (FIB-4) followed by FIB-Net and a three-step algorithm (Three-step#1) using FIB-4 followed by FIB-Net and SWE were used to simulate screening scenarios where liver stiffness measurements were not or were available, respectively. Measures of diagnostic accuracy were calculated using liver biopsy as the reference standard and compared between FIB-4, SWE, FIB-Net, and European Association for the Study of the Liver guidelines (ie, FIB-4 followed by SWE), along with sequential algorithms. Results The training, validation, and test data sets included 3067 (median age, 42 years [IQR, 33-53 years]; 2083 male), 1599 (median age, 41 years [IQR, 33-51 years]; 1124 male), and 1228 (median age, 44 years [IQR, 33-55 years]; 741 male) patients, respectively. FIB-Net obtained a noninferior specificity with a margin of 5% (P < .001) compared with SWE (80% vs 82%). The Two-step#1 algorithm showed higher specificity and positive predictive value (PPV) than FIB-4 (specificity, 79% vs 57%; PPV, 44% vs 32%) while reducing unnecessary referrals by 42%. The Three-step#1 algorithm had higher specificity and PPV compared with European Association for the Study of the Liver guidelines (specificity, 94% vs 88%; PPV, 73% vs 64%) while reducing unnecessary referrals by 35%. Conclusion A sequential algorithm combining FIB-4 and a US DL model showed higher diagnostic accuracy and improved referral management for all-cause advanced liver fibrosis compared with FIB-4 or the DL model alone. © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Ghosh in this issue.

Novel Photocatalyst Based on Through-Space Charge Transfer Induced Intersystem Crossing Enables Rapid and Efficient Polymerization Under Low-Power Excitation Light.

Currently, most photoredox catalysis polymerization systems are limited by high excitation power, long polymerization time, or the requirement of electron donors due to the precise design of efficient photocatalysts still poses a great challenge. Herein, we propose a new approach: the creation of efficient photocatalysts having low ground state oxidation potentials and high excited state energy levels, along with through-space charge transfer (TSCT) induced intersystem crossing (ISC) properties. A cabazole-naphthalimide (NI) dyad (NI-1) characterized by long triplet excited state lifetime (τT=62 µs), satisfactory ISC efficiency (ΦΔ=54.3 %) and powerful reduction capacity [Singlet: E1/2 (PC+1/*PC)=-1.93 eV, Triplet: E1/2 (PC+1/*PC)=-0.84 eV] was obtained. An efficient and rapid polymerization (83 % conversion of 1 mM monomer in 30 s) was observed under the conditions of without electron donor, low excitation power (10 mW cm-2) and low catalyst (NI-1) loading (<50 µM). In contrast, the conversion rate was lower at 29 % when the reference catalyst (NI-4) was used for photopolymerization under the same conditions, demonstrating the advantage of the TSCT photocatalyst. Finally, the TSCT material was used as a photocatalyst in practical lithography for the first time, achieving pattern resolutions of up to 10 µm.

Nucleic-acid-base photofunctional cocrystal for information security and antimicrobial applications.

Cocrystal engineering is an efficient and simple strategy to construct functional materials, especially for the exploitation of novel and multifunctional materials. Herein, we report two kinds of nucleic-acid-base cocrystal systems that imitate the strong hydrogen bond interactions constructed in the form of complementary base pairing. The two cocrystals studied exhibit different colors of phosphorescence from their monomeric counterparts and show the feature of rare high-temperature phosphorescence. Mechanistic studies reveal that the strong hydrogen bond network stabilizes the triplet state and suppresses non-radiative transitions, resulting in phosphorescence even at 425 K. Moreover, the isolation effects of the hydrogen bond network regulate the interactions between the phosphor groups, realizing the manipulation from aggregation to single-molecule phosphorescence. Benefiting from the long-lived triplet state with a high quantum yield, the generation of reactive oxygen species by energy transfer is also available to utilize for some applications such as in photodynamic therapy and broad-spectrum microbicidal effects. In vitro experiments show that the cocrystals efficiently kill bacteria on a tooth surface and significantly help prevent dental caries. This work not only provides deep insight into the relationship of the structure-properties of cocrystal systems, but also facilitates the design of multifunctional cocrystal materials and enriches their potential applications.

Collaborative Enhancement of Consistency and Accuracy in US Diagnosis of Thyroid Nodules Using Large Language Models.

Background Large language models (LLMs) hold substantial promise for medical imaging interpretation. However, there is a lack of studies on their feasibility in handling reasoning questions associated with medical diagnosis. Purpose To investigate the viability of leveraging three publicly available LLMs to enhance consistency and diagnostic accuracy in medical imaging based on standardized reporting, with pathology as the reference standard. Materials and Methods US images of thyroid nodules with pathologic results were retrospectively collected from a tertiary referral hospital between July 2022 and December 2022 and used to evaluate malignancy diagnoses generated by three LLMs-OpenAI's ChatGPT 3.5, ChatGPT 4.0, and Google's Bard. Inter- and intra-LLM agreement of diagnosis were evaluated. Then, diagnostic performance, including accuracy, sensitivity, specificity, and area under the receiver operating characteristic curve (AUC), was evaluated and compared for the LLMs and three interactive approaches: human reader combined with LLMs, image-to-text model combined with LLMs, and an end-to-end convolutional neural network model. Results A total of 1161 US images of thyroid nodules (498 benign, 663 malignant) from 725 patients (mean age, 42.2 years ± 14.1 [SD]; 516 women) were evaluated. ChatGPT 4.0 and Bard displayed substantial to almost perfect intra-LLM agreement (κ range, 0.65-0.86 [95% CI: 0.64, 0.86]), while ChatGPT 3.5 showed fair to substantial agreement (κ range, 0.36-0.68 [95% CI: 0.36, 0.68]). ChatGPT 4.0 had an accuracy of 78%-86% (95% CI: 76%, 88%) and sensitivity of 86%-95% (95% CI: 83%, 96%), compared with 74%-86% (95% CI: 71%, 88%) and 74%-91% (95% CI: 71%, 93%), respectively, for Bard. Moreover, with ChatGPT 4.0, the image-to-text-LLM strategy exhibited an AUC (0.83 [95% CI: 0.80, 0.85]) and accuracy (84% [95% CI: 82%, 86%]) comparable to those of the human-LLM interaction strategy with two senior readers and one junior reader and exceeding those of the human-LLM interaction strategy with one junior reader. Conclusion LLMs, particularly integrated with image-to-text approaches, show potential in enhancing diagnostic medical imaging. ChatGPT 4.0 was optimal for consistency and diagnostic accuracy when compared with Bard and ChatGPT 3.5. © RSNA, 2024 Supplemental material is available for this article.

Interleukin-1ß polarization in M1 macrophage mediates myocardial fibrosis in diabetes.

BACKGROUND: Diabetes is a global health problem whose common complication is diabetic cardiomyopathy, characterized by chronic inflammation of the heart muscle. Macrophages are the main white blood cells found in the resting heart. Therefore, we investigated the underling mechanism of macrophage on myocardial fibrosis in diabetes. METHODS: Here, echocardiography was utilized to evaluate cardiac function, and the degree of myocardial fibrosis was assessed using Masson's trichrome staining, followed by single-cell RNA sequencing (scRNA-seq) to analyze the phenotype, function, developmental trajectory, and interactions between immune cells, endothelial cells (ECs), and fibroblasts (FBs) in the hearts of db/db mice at different stages of diabetes. Macrophages and cardiac fibroblasts were also co-cultured in order to study the signaling between macrophages and fibroblasts. RESULTS: We found that with the development of diabetes mellitus, myocardial hypertrophy and fibrosis occurred that was accompanied by cardiac dysfunction. A significant proportion of immune cells, endothelial cells, and fibroblasts were identified by RNA sequencing. The most significant changes observed were in macrophages, which undergo M1 polarization and are critical for oxidative stress and extracellular matrix (ECM) formation. We further found that M1 macrophages secreted interleukin-1ß (IL-1ß), which interacted with the receptor on the surface of fibroblasts, to cause myocardial fibrosis. In addition, crosstalk between M1 macrophages and endothelial cells also plays a key role in fibrosis and immune response regulation through IL-1ß and corresponding receptors. CONCLUSIONS: M1 macrophages mediate diabetic myocardial fibrosis through interleukin-1ß interaction with fibroblasts.

Dual-rotor strategy for organic cocrystals with enhanced near-infrared photothermal conversion.

Organic cocrystal engineering provides a promising route to promote the near-infrared (NIR) light harvesting and photothermal conversion (PTC) abilities of small organic molecules through the rich noncovalent bond interactions of D/A units. Besides, the single-bond rotatable groups known as "rotors" are considered to be conducive to the nonradiative transitions of the excited states of organic molecules. Herein, we propose a single-/double-bond dual-rotor strategy to construct D-A cocrystals for NIR PTC application. The results reveal that the cocrystal exhibits an ultra-broadband absorption from 300 nm to 2000 nm profiting from the strong π-π stacking and charge transfer interactions, and the weakened p-π interaction. More importantly, the PTC efficiency of cocrystals at 1064 nm in the NIR-II region can be largely enhanced by modulating the number of rotor groups and the F-substituents of D/A units. As is revealed by fs-TA spectroscopy, the superior NIR PTC performance can be attributed to the nonradiative decays of excited states induced by the free rotation of the single-bond rotor (-CH3) from the donors and the inactive double-bond rotor ([double bond, length as m-dash]C(C[triple bond, length as m-dash]N)2) being in the active form of [-C(C[triple bond, length as m-dash]N)2] in the excited states from the acceptors. This prototype displays a promising route to extend the functionalization of small organic molecules based on organic cocrystal engineering.

CP-AFM Molecular Tunnel Junctions with Alkyl Backbones Anchored Using Alkynyl and Thiol Groups: Microscopically Different Despite Phenomenological Similarity.

In this paper, we report results on the electronic structure and transport properties of molecular junctions fabricated via conducting probe atomic force microscopy (CP-AFM) using self-assembled monolayers (SAMs) of n-alkyl chains anchored with acetylene groups (CnA; n = 8, 9, 10, and 12) on Ag, Au, and Pt electrodes. We found that the current-voltage (I-V) characteristics of CnA CP-AFM junctions can be very accurately reproduced by the same off-resonant single-level model (orSLM) successfully utilized previously for many other junctions. We demonstrate that important insight into the energy-level alignment can be gained from experimental data of transport (processed via the orSLM) and ultraviolet photoelectron spectroscopy combined with ab initio quantum chemical information based on the many-body outer valence Green's function method. Measured conductance GAg < GAu < GPt is found to follow the same ordering as the metal work function ΦAu < ΦAu < ΦPt, a fact that points toward a transport mediated by an occupied molecular orbital (MO). Still, careful data analysis surprisingly revealed that transport is not dominated by the ubiquitous HOMO but rather by the HOMO-1. This is an important difference from other molecular tunnel junctions with p-type HOMO-mediated conduction investigated in the past, including the alkyl thiols (CnT) to which we refer in view of some similarities. Furthermore, unlike in CnT and other junctions anchored with thiol groups investigated in the past, the AFM tip causes in CnA an additional MO shift, whose independence of size (n) rules out significant image charge effects. Along with the prevalence of the HOMO-1 over the HOMO, the impact of the "second" (tip) electrode on the energy level alignment is another important finding that makes the CnA and CnT junctions different. What ultimately makes CnA unique at the microscopic level is a salient difference never reported previously, namely, that CnA's alkyne functional group gives rise to two energetically close (HOMO and HOMO-1) orbitals. This distinguishes the present CnA from the CnT, whose HOMO stemming from its thiol group is well separated energetically from the other MOs.

Red-light operable photosensitizer with symmetry-breaking charge transfer induced intersystem crossing for polymerization of methyl methacrylate.

We present a red light-activated zincII bis(dipyrrin) symmetry breaking charge transfer (SBCT) architecture, showing a large molar absorption coefficient (ε = 15.4 × 104 M-1 cm-1), high reactive singlet oxygen generation efficiency (ΦΔ ≈ 0.8) and long-lived triplet state (τT = 150 µs) compared to the donor-acceptor analogue dipyrrin-BF2 complex, highlighting the superiority of the SBCT approach. For the first time, we demonstrated the potential of a SBCT scaffold in red-light-induced methyl methacrylate (MMA) polymerization, using a dual photocatalyst excitation approach.

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

To study the intersystem crossing (ISC) and the spatial confinement of the triplet excited states of organic chromophores, we prepared a series of Bodipy dimers. We found that the connection position of the two units has a significant effect on the absorption and fluorescence. Singlet oxygen quantum yields of 3.8-12.4% were observed for the dimers, which are independent of solvent polarity. Nanosecond transient absorption spectra indicate the population of long-lived triplet excited states with lifetimes (τT) of 45-454 µs. Pulsed laser-excited time-resolved electron paramagnetic resonance (TREPR) spectra show that the T1 triplet states are essentially delocalized, which is different from the case for the previously reported Bodipy dimers. The TREPR spectra of the triplet states imply that the delocalization over the whole dimer essentially depends on the electron density of the carbon atoms at the connection sites. This property may become a universal rule for controlling the T1 state confinement in multichromophore organic molecules.

Anion-Counterion Strategy toward Organic Cocrystal Engineering for Near-Infrared Photothermal Conversion and Solar-Driven Water Evaporation.

An anion-counterion strategy is proposed to construct organic mono-radical charge-transfer cocrystals for near-infrared photothermal conversion and solar-driven water evaporation. Ionic compounds with halogen anions as the counterions serve as electron donors, providing the necessary electrons for efficient charge transfer with unchanged skeleton atoms and structures as well as the broad red-shifted absorption (200-2000 nm) and unprecedented photothermal conversion efficiency (~90.5 %@808 nm) for the cocrystals. Based on these cocrystals, an excellent solar-driven interfacial water evaporation rate up to 6.1±1.1 kg ⋅ m-2 ⋅ h-1 under 1 sun is recorded due to the comprehensive evaporation effect from the cocrystal loading in polyurethane foams and chimney addition, such performance is superior to the reported results on charge-transfer cocrystals or other materials for solar-driven interfacial evaporation. This prototype exhibits the great potential of cocrystals prepared by the one-step mechanochemistry method in practical large-scale seawater desalination applications.

Integrative analysis of transcriptome and proteome in primary Sjögren syndrome.

OBJECTIVE: Primary Sjögren's syndrome (pSS) is a intricate autoimmune disease mainly characterized of immune-mediated destruction of exocrine tissues, such as salivary and lacrimal glands, occurring dry mouth and eyes. Although some breakthroughs in understanding pSS have been uncovered, many questions remain about its pathogenesis, especially the internal relations between exocrine glands and secretions. METHOD: Transcriptomic and proteomic analyses were conducted on salivary tissues and saliva in experimental Sjögren syndrome (ESS). The ESS model was established by immunization with salivary gland protein. The expression of mRNAs and proteins in salivary tissues and saliva were determined by high-throughput sequencing transcriptomic analysis and LC-MS/MS-based proteome, respectively. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were used to recognize dysregulated genes and proteins. The association between RNA and protein abundance was investigated to provides a comprehensive understanding of RNA-protein correlations in the pathogenesis of pSS. RESULTS: As a result, we successfully established the ESS model. We recognized 3221 differentially expressed genes (DEGs) and 253 differentially expressed proteins (DEPs). The sample analysis showed that 61 proteins overlapped through the integrative analysis of transcriptomics and proteomics data. The enrichment pathway analysis of DEGs and DEPs in samples showed alterations in renin-angiotensin-system (RAS), lysosome, and apoptosis. Notably, we found that some genes, such as AGT, FN1, Klk1b26, Klk1, Klk1b5, Klk1b3 had a consistent trend in the regulation at the RNA and protein levels and might be potential diagnostic biomarkers of pSS. CONCLUSION: Herein, we found critical processes and potential biomakers that may contribute to pSS pathogenesis by analyzing dysregulated genes and pathways. Additionally, the integrative multi-omics datasets provided additional insight into understanding complicated disease mechanisms.

Primary Structural Units "D+A-" Ion Pairs Dominating Near-Infrared Photothermal Conversion of Organic Ionic Cocrystals.

The specific stacking mode of D/A blocks is often considered to largely determine the physicochemical properties of cocrystals. However, this rule may fail when encountering a large degree of (integer or near-integer) charge transfer situations. Herein, we explore the extensive correlations between the possible smallest structural units, stacking modes, and near-infrared photothermal conversion (NIR-PTC) properties of F4TCNQ-based cocrystals with typical features of integer-charge-transfer. Surprisingly, these cocrystals with distinct stacking modes display analogous D-A interactions, broad red-shift absorption, ultrafast (1-3 ps) relaxation dynamics of excited states, and excellent NIR-PTC properties. This supports that the resulting "D+A-" ion pairs from integer-charge-transfer may serve as the primary structural units beneath the secondary stacking modes to dominate the property of cocrystals. The stacking modes play an important but only secondary role. This work provides new insights into the structure-dynamics-property correlations and modular design of organic cocrystals for PTC and other applications.

Photocatalytic CO2 Reduction Coupled with Oxidation of Benzyl Alcohol over CsPbBr3@PANI Nanocomposites.

Herein, we successfully prepare conductive polyaniline (PANI)-encapsulated CsPbBr3 perovskite nanocrystals (PNCs) that demonstrate much improved photocatalytic performance and stability toward the CO2 reduction reaction (CRR) coupled with oxidation of benzyl alcohol (BA) to benzaldehyde. Due to the acid-base interaction between CO2 and PANI, CO2 molecules are selectively adsorbed on PANI in the form of carbamate. As a result, the rate of production of CO (rCO) reaches 26.1 µmol g-1 h-1 with a selectivity of 98.1%, which is in good agreement with the rate of oxidation (∼27.0 µmol g-1 h-1) of BA. Such a high reduction/oxidation rate is enabled by the fast electron transfer (∼2.2 ps) from PNCs to PANI, as revealed by femtosecond transient absorption spectroscopy. Moreover, because of the benefit of the encapsulation of PANI, no significant decrease in rCO is observed in a 10 h CRR test. This work offers insight into how to simultaneously achieve improved photocatalytic performance and stability of CsPbX3 PNCs.

A Two-stage Diagnostic Framework for Post-ablation Treatment Response Assessment in Patients with Hepatocellular Carcinoma.

Contrast-enhanced ultrasound (CEUS) video plays an important role in post-ablation treatment response assessment in patients with hepatocellular carcinoma (HCC). However, the assessment of treatment response using CEUS video is challenging due to issues such as high inter-frame data repeatability, small ablation area and poor imaging quality of CEUS video. To address these issues, we propose a two-stage diagnostic framework for post-ablation treatment response assessment in patients with HCC using CEUS video. The first stage is a location stage, which is used to locate the ablation area. At this stage, we propose a Yolov5-SFT to improve the location results of the ablation area and a similarity comparison module (SCM) to reduce data repeatability. The second stage is an assessment stage, which is used for the evaluation of postoperative efficacy. At this stage, we design an EfficientNet-SK to improve assessment accuracy. The Experimental results on the self-collected data show that the proposed framework outperforms other selected algorithms, and can effectively assist doctors in the assessment of post-ablation treatment response.

Predicting T Cell-Inflamed Gene Expression Profile in Hepatocellular Carcinoma Based on Dynamic Contrast-Enhanced Ultrasound Radiomics.

Purpose: The T cell-inflamed gene expression profile (GEP) quantifies 18 genes' expression indicative of a T-cell immune tumor microenvironment, playing a crucial role in the immunotherapy of hepatocellular carcinoma (HCC). Our study aims to develop a radiomics-based machine learning model using contrast-enhanced ultrasound (CEUS) for predicting T cell-inflamed GEP in HCC. Methods: The primary cohort of HCC patients with preoperative CEUS and RNA sequencing data of tumor tissues at the single center was used to construct the model. A total of 5936 radiomics features were extracted from the regions of interest in representative images of each phase, and the least absolute shrinkage and selection operator and logistic regression were used to construct four models including three phase-specific models and an integrated model. The area under the curve (AUC) was calculated to evaluate the performance of the model. The independent cohort of HCC patients with preoperative CEUS and Immunoscore based on immunohistochemistry and digital pathology was used to validate the correlation between model prediction value and T-cell infiltration. Results: There were 268 patients enrolled in the primary cohort and 46 patients enrolled in the independent cohort. Compared with the other three models, the AP model constructed by 36 arterial phase (AP) features showed good performance with a mean AUC of 0.905 in the 5-fold cross-validation and was easier to apply in the clinical setting. The decision curve and calibration curve confirmed the clinical utility of the model. In the independent cohort, patients with high Immunoscores showed significantly higher GEP prediction values than those with low Immunoscores (t=-2.359, p=0.029). Conclusion: The CEUS-based model is a reliable predictive tool for T cell-inflamed GEP in HCC, and might facilitate individualized immunotherapy decision-making.

Boosting the Release of Leaving Group from Blebbistatin Derivative Photocages via Enhancing Intramolecular Charge Transfer and Stabilizing Cationic Intermediate.

Blebbistatin (Bleb) derivatives are a visible light photocage platform. During the photocleavage process, intramolecular charge transfer (ICT) and cationic intermediates play a decisive role. However, slow photolysis rate and low photolysis quantum yield are the main problems for Bleb's derivatives. Herein, by introducing a substituted OCH3 group at the para-position of the D ring, Bleb and Bleb derivatives with various leaving groups were synthesized and studied, and the photolysis performance was unveiled by steady-state spectra, photolysis rate experiments, photolysis quantum yield, and density functional theory calculations. Substituted OCH3 derivatives of Bleb may enhance the photolysis rate and increase the photolysis quantum yield because the electron-donating group can promote the ICT process and stabilize the cationic intermediate during the photolytic reaction. More generally, the insights gained from this structure-reactivity relationship may provide theoretical guidance and aid in the development of new highly efficient photoreactions.