Extended Surface Bands Enabled Lasing Emission and Wavelength Switch from Sulfur Quantum Dots.

The development of a lasing wavelength switch, particularly from a single inorganic gain material, is challenging but highly demanded for advanced photonics. Nonetheless, all current lasing emission of inorganic gain materials arises from band-edge states, and the inherent fixed bandgap limitation of the band-edge system leads to the inaccessibility of lasing wavelength switching from a single inorganic gain material. Here the realization of a single inorganic gain material-based lasing wavelength switch is reported by proposing an alternative lasing emission strategy, that is, lasing emission from surface gain. Previous efforts to achieve surface-gain-enabled lasing emission have been hindered by the limited gain volume provided by surface states due to the broad emission bandwidth and/or low emission efficiency. This challenge is overcome by introducing extended surface bands onto the surface of sulfur quantum dots. The extended surface bands contribute to a high photoluminescence quantum yield and narrow emission bandwidth, thereby providing sufficient gain volume and facilitating stimulated emission. When combined with whispering gallery mode microcavity, surface gain enabled lasing emission manifests an ultralow threshold of 8.3 µJ cm-2. Remarkably, the reconfigurable perturbation to surface gain, facilitated by molecular affinity, allows for the realization of the lasing wavelength switch from a single inorganic gain material.

Silvaticusins A-D: ent-kaurane diterpenoids and a cyclobutane-containing ent-kaurane dimer from Isodon silvaticus.

Three new ent-kaurane diterpenoids, silvaticusins A-C (1-3), along with a new ent-kaurane dimer silvaticusin D (4) were isolated from the aerial parts of Isodon silvaticus. The structures of these new compounds were established mainly by comprehensive analysis of their NMR and MS data. The absolute configuration of compounds 1 and 4 were determined using a single-crystal X-ray diffraction and computational methods, respectively. Compounds 2 and 3 were found to exhibit remarkable cytotoxic effects against five human tumor cell lines (HL-60, A-549, SMMC-7721, MDA-MB-231, and SW-480), with IC50 values spanning from 1.27 ± 0.08 to 7.52 ± 0.33 µM.

Structurally diverse ent-clerodanoids from the aerial parts of Isodon scoparius.

Scoparodane C (1), a diterpenoid with a rare 3,4-seco-3-nor-2,11-epoxy-ent-clerodane scaffold, was obtained from the aerial parts of Isodon scoparius, along with isocopariusines A-E (2-6), five ent-clerodanoids featuring a 5/6-fused ring system, and isocopariusines F-H (7-9), three common ent-clerodanoids. The structures of these previously undescribed compounds were established by a combination of spectroscopic analysis, X-ray diffraction, chemical derivatization, and quantum chemical calculation. Remarkably, isocopariusine B (3) showed strong resistance reversal activity against fluconazole-resistant Candida albicans.

Polaron engineering promotes NIR-II absorption of carbon quantum dots for bioimaging and cancer therapy.

Recent years have witnessed a surge of interest in tuning the optical properties of organic semiconductors for diverse applications. However, achieving control over the optical bandgap in the second near-infrared (NIR-II) window has remained a major challenge. To address this, here we report a polaron engineering strategy that introduces diverse defects into carbon quantum dots (CQDs). These defects induce lattice distortions resulting in the formation of polarons, which can absorb the near-field scattered light. Furthermore, the formed polarons in N-related vacancies can generate thermal energy through the coupling of lattice vibrations, while the portion associated with O-related defects can return to the ground state in the form of NIR-II fluorescence. On the basis of this optical absorption model, these CQDs have been successfully applied to NIR-II fluorescence imaging and photothermal therapy. This discovery could open a promising route for the polarons of organic semiconductor materials as NIR-II absorbers in nanomedical applications.

Isoxerophilusins A and B, Two Novel Polycyclic Asymmetric Diterpene Dimers from Isodon xerophilus: Structural Elucidation, Modification, and Inhibitory Activities against α-Glucosidase.

Isoxerophilusins A (1) and B (2), two unprecedented diterpene heterodimers biogenetically from ent-atisanes and abietanes, were isolated from the rhizomes of Isodon xerophilus. Their structures were determined by extensive spectroscopic analysis and single-crystal X-ray diffraction. Selective esterification of 1 generated 11 new derivatives. All derivatives showed excellent α-glucosidase inhibitory activity in comparison to acarbose. Compounds 12 and 13 demonstrated significant inhibition against α-glucosidase with IC50 values of 4.92 and 3.83 µM, respectively.

Recent advances in the application of [2 + 2] cycloaddition in the chemical synthesis of cyclobutane-containing natural products.

Cyclobutanes are distributed widely in a large class of natural products featuring diverse pharmaceutical activities and intricate structural frameworks. The [2 + 2] cycloaddition is unequivocally the primary and most commonly used method for synthesizing cyclobutanes. In this review, we have summarized the application of the [2 + 2] cycloaddition with different reaction mechanisms in the chemical synthesis of selected cyclobutane-containing natural products over the past decade.

Deciphering the molecular landscape: evolutionary progression from gynecomastia to aggressive male breast cancer.

BACKGROUND: Gynecomastia denotes the benign proliferation of glandular breast tissue and stands as a recognized risk factor for male breast cancer. Nonetheless, the underlying carcinogenic mechanisms orchestrating the progression from gynecomastia to cancer remain poorly understood. METHODS: This study employed single-cell RNA sequencing (scRNA-seq) to meticulously dissect the cellular landscape of gynecomastia and unravel potential associations with male breast cancer at a single-cell resolution. Pseudotime and evolutionary analyses were executed to delineate the distinct features characterizing gynecomastia and male breast cancer. The TCGA database, along with cell-cell communication analysis and immunohistochemistry staining, was harnessed to validate differential gene expression, specifically focusing on CD13. RESULT: From the copy number variation profiles and evolutionary tree, we inferred shared mutation characteristics (18p+ and 18q+) underpinning both conditions. The developmental trajectory unveiled an intriguing overlap between gynecomastia and malignant epithelial cells. Moreover, the differential gene CD13 emerged as a common denominator in both gynecomastia and male breast cancer when compared with normal mammary tissue. Cell-cell interaction analysis and communication dynamics within the tumor microenvironment spotlighted distinctions between CD13+ and CD13- subsets, with the former exhibiting elevated expression of FGFR1-FGF7. CONCLUSIONS: Our investigation provides novel insights into the evolutionary progression from gynecomastia to male breast cancer, shedding light on the pivotal role of CD13 in driving this transition. The identification of CD13 as a potential therapeutic target suggests the feasibility of CD13-targeted interventions, specifically tailored for male breast cancer treatment.

Discovery and bioinspired total syntheses of unprecedented sesquiterpenoid dimers unveiled bifurcating [4 + 2] cycloaddition and target differentiation of enantiomers.

[4 + 2] cycloaddition has led to diverse polycyclic chiral architectures, serving as novel sources for organic synthesis and biological exploration. Here, an unprecedented class of cadinane sesquiterpene [4 + 2] dimers, henryinins A-E (1-5), with a unique 6/6/6/6/6-fused pentacyclic system, were isolated from Schisandra henryi. The divergent total syntheses of compounds 1-5 and their enantiomers (6-10) were concisely accomplished in eight linear steps using a protection-free approach. Mechanistic studies illustrated the origin of selectivity in the key [4 + 2] cycloaddition as well as the inhibition of reaction pathway bifurcation via desymmetrization. The chemical proteomics results showed that a pair of enantiomers shared common targets (PRDX5 C100 and BLMH C73) and had unique targets (USP45 C588 for 4 and COG7 C419 for 9). This work provides experimental evidence for the discovery of unprecedented cadinane dimers from selective Diels-Alder reaction and a powerful strategy to explore the biological properties of natural products.

Discovery of Natural Potent HMG-CoA Reductase Degraders for Lowering Cholesterol.

Exploitation of key protected wild plant resources makes great sense, but their limited populations become the major barrier. A particular strategy for breaking this barrier was inspired by the exploration of a resource-saving fungal endophyte Penicillium sp. DG23, which inhabits the key protected wild plant Schisandra macrocarpa. Chemical studies on the cultures of this strain afforded eight novel indole diterpenoids, schipenindolenes A-H (1-8), belonging to six diverse skeleton types. Importantly, semisyntheses suggested some key nonenzymatic reactions constructing these molecules and provided targeted compounds, in particular schipenindolene A (Spid A, 1) with low natural abundance. Remarkably, Spid A was the most potent HMG-CoA reductase (HMGCR) degrader among the indole diterpenoid family. It degraded statin-induced accumulation of HMGCR protein, decreased cholesterol levels and acted synergistically with statin to further lower cholesterol. Mechanistically, transcriptomic and proteomic profiling suggested that Spid A potentially activated the endoplasmic reticulum-associated degradation (ERAD) pathway to enhance the degradation of HMGCR, while simultaneously inhibiting the statin-activated expression of many key enzymes in the cholesterol and fatty acid synthesis pathways, thereby strengthening the efficacy of statins and potentially reducing the side effects of statins. Collectively, this study suggests the potential of Spid A for treating cardiovascular disease.

Single-cell transcriptome analysis indicates fatty acid metabolism-mediated metastasis and immunosuppression in male breast cancer.

Male breast cancer (MBC) is a rare but aggressive malignancy with cellular and immunological characteristics that remain unclear. Here, we perform transcriptomic analysis for 111,038 single cells from tumor tissues of six MBC and thirteen female breast cancer (FBC) patients. We find that that MBC has significantly lower infiltration of T cells relative to FBC. Metastasis-related programs are more active in cancer cells from MBC. The activated fatty acid metabolism involved with FASN is related to cancer cell metastasis and low immune infiltration of MBC. T cells in MBC show activation of p38 MAPK and lipid oxidation pathways, indicating a dysfunctional state. In contrast, T cells in FBC exhibit higher expression of cytotoxic markers and immune activation pathways mediated by immune-modulatory cytokines. Moreover, we identify the inhibitory interactions between cancer cells and T cells in MBC. Our study provides important information for understanding the tumor immunology and metabolism of MBC.

IGF2BP3 mediates the mRNA degradation of NF1 to promote triple-negative breast cancer progression via an m6A-dependent manner.

BACKGROUND: N6-methyladenosine (m6A) is an abundant reversible modification in eukaryotic mRNAs. Emerging evidences indicate that m6A modification plays a vital role in tumourigenesis. As a crucial reader of m6A, IGF2BP3 usually mediates the stabilisation of mRNAs via an m6A-dependent manner. But the underlying mechanism of IGF2BP3 in the tumourigenesis of triple-negative breast cancer (TNBC) is unclear. METHODS: TCGA cohorts were analysed for IGF2BP3 expression and IGF2BP3 promoter methylation levels in different breast cancer subtypes. Colony formation, flow cytometry assays and subcutaneous xenograft were performed to identify the phenotype of IGF2BP3 in TNBC. RNA/RNA immunoprecipitation (RIP)/methylated RNA immunoprecipitation (MeRIP) sequencing and luciferase assays were used to certify the target of IGF2BP3 in TNBC cells. RESULTS: IGF2BP3 was highly expressed in TNBC cell lines and tissues. TET3-mediated IGF2BP3 promoter hypomethylation led to the upregulation of IGF2BP3. Knocking down IGF2BP3 markedly reduced the proliferation of TNBC in vitro and in vivo. Intersection co-assays revealed that IGF2BP3 decreased neurofibromin 1 (NF1) stabilisation via an m6A-dependent manner. NF1 knockdown could rescue the phenotypes of IGF2BP3 knockdown cells partially. CONCLUSION: TET3-mediated IGF2BP3 accelerated the proliferation of TNBC by destabilising NF1 mRNA via an m6A-dependent manner. This suggests that IGF2BP3 could be a potential therapeutic target for TNBC.

Near-Unity Emitting, Widely Tailorable, and Stable Exciton Concentrators Built from Doubly Gradient 2D Semiconductor Nanoplatelets.

The strength of electrostatic interactions (EIs) between electrons and holes within semiconductor nanocrystals profoundly affects the performance of their optoelectronic systems, and different optoelectronic devices demand distinct EI strength of the active medium. However, achieving a broad range and fine-tuning of the EI strength for specific optoelectronic applications is a daunting challenge, especially in quasi two-dimensional core-shell semiconductor nanoplatelets (NPLs), as the epitaxial growth of the inorganic shell along the direction of the thickness that solely contributes to the quantum confined effect significantly undermines the strength of the EI. Herein we propose and demonstrate a doubly gradient (DG) core-shell architecture of semiconductor NPLs for on-demand tailoring of the EI strength by controlling the localized exciton concentration via in-plane architectural modulation, demonstrated by a wide tuning of radiative recombination rate and exciton binding energy. Moreover, these exciton-concentration-engineered DG NPLs also exhibit a near-unity quantum yield, high photo- and thermal stability, and considerably suppressed self-absorption. As proof-of-concept demonstrations, highly efficient color converters and high-performance light-emitting diodes (external quantum efficiency: 16.9%, maximum luminance: 43,000 cd/m2) have been achieved based on the DG NPLs. This work thus provides insights into the development of high-performance colloidal optoelectronic device applications.

Stable continuous-wave lasing from discrete cesium lead bromide quantum dots embedded in a microcavity.

All-inorganic cesium lead bromide (CsPbBr3) quantum dots (QDs) with high photoluminescence (PL) quantum efficiency have been reported as ideal gain materials for high-performance lasers. Nevertheless, isolated CsPbBr3 QDs have not achieved lasing emission (LE) due to finite absorption cross-section. Here, we demonstrate continuous-wave lasing of isolated CsPbBr3 QDs embedded in a microcavity. Distributed Bragg reflectors (DBRs), together with isolated CsPbBr3 QDs in a polymer matrix, are introduced to construct a vertical-cavity surface-emitting laser (VCSEL), which exhibits stable single-mode lasing emissions with an ultra-low threshold of 8.8 W cm-2 and a high Q factor of 1787. Such perovskite-based microcavity structures sustain highly stable excitons at room temperature and can provide an excellent experimental platform to further study the single-particle nano-lasers and quantum physics frontiers such as exciton-polariton condensation, single-photon emission, and optical quantum communication.

A Modified 1H-NMR Quantification Method of Ephedrine Alkaloids in Ephedrae Herba Samples.

A previous 1H-NMR method allowed the quantification of ephedrine alkaloids; however, there were some disadvantages. The cyclized derivatives resulted from the impurities of diethyl ether were identified and benzene was selected as the better extraction solvent. The locations of ephedrine alkaloids were confirmed with 2D NMR. Therefore, a specific 1H-NMR method has been modified for the quantification of ephedrine alkaloids. Accordingly, twenty Ephedrae Herba samples could be classified into three classes: (I) E. sinica-like species; (II) E. intermedia-like species; (III) others (lower alkaloid contents). The results indicated that ephedrine and pseudoephedrine are the major alkaloids in Ephedra plants, but the concentrations vary greatly determined by the plant species and the collection locations.

Greatly Enhanced Resonant Exciton-Trion Conversion in Electrically Modulated Atomically Thin WS2 at Room Temperature.

Excitonic resonance in atomically thin semiconductors offers a favorite platform to study 2D nanophotonics in both classical and quantum regimes and promises potentials for highly tunable and ultra-compact optical devices. The understanding of charge density dependent exciton-trion conversion is the key for revealing the underlaying physics of optical tunability. Nevertheless, the insufficient and inefficient light-matter interactions hinder the observation of trionic phenomenon and the development of excitonic devices for dynamic power-efficient electro-optical applications. Here, by engaging an optical cavity with atomically thin transition metal dichalcogenides (TMDCs), greatly enhanced exciton-trion conversion is demonstrated at room temperature (RT) and achieve electrical modulation of reflectivity of ≈40% at exciton and 7% at trion state, which correspondingly enables a broadband large phase tuning in monolayer tungsten disulfide. Besides the absorptive conversion, ≈100% photoluminescence conversion from excitons to trions is observed at RT, illustrating a clear physical mechanism of an efficient exciton-trion conversion for extraordinary optical performance. The results indicate that both excitons and trions can play significant roles in electrical modulation of the optical parameters of TMDCs at RT. The work shows the real possibility for realizing electrical tunable and multi-functional ultra-thin optical devices using 2D materials.

Higher-order topological polariton corner state lasing.

Unlike conventional laser, the topological laser is able to emit coherent light robustly against disorders and defects because of its nontrivial band topology. As a promising platform for low-power consumption, exciton polariton topological lasers require no population inversion, a unique property that can be attributed to the part-light-part-matter bosonic nature and strong nonlinearity of exciton polaritons. Recently, the discovery of higher-order topology has shifted the paradigm of topological physics to topological states at boundaries of boundaries, such as corners. However, such topological corner states have never been realized in the exciton polariton system yet. Here, on the basis of an extended two-dimensional Su-Schrieffer-Heeger lattice model, we experimentally demonstrate the topological corner states of perovskite polaritons and achieved polariton corner state lasing with a low threshold (approximately microjoule per square centimeter) at room temperature. The realization of such polariton corner states also provides a mechanism of polariton localization under topological protection, paving the way toward on-chip active polaritonics using higher-order topology.

Cyclobutane-Containing Meroditerpenoids, (+)-Isoscopariusins B and C: Structure Elucidation and Biomimetic Synthesis.

(+)-Isoscopariusins B (1) and C (2), two meroditerpenoids containing a 6/6/4 tricyclic carbon skeleton and seven continuous stereocenters, were identified from Isodon scoparius. The structures were determined by nuclear magnetic resonance analysis and concise biomimetic syntheses from readily available alkene 5 in seven and six steps, respectively. An intermolecular [2+2] photocycloaddition with cooperative catalysis of a Lewis acid and an Ir photocatalyst was used to construct a cyclobutane core with four stereogenic centers.

Four new lanostane triterpenoids featuring extended π-conjugated systems from the stems of Kadsura coccinea.

Four new 14(13 → 12)-abeolanostane triterpenoids featuring extended π-conjugated systems, kadcoccitanes E-H (1-4), were obtained from the stems of Kadsura coccinea through using a HPLC - UV-guided approach. Their structural and configurational determination was accomplished through extensive spectroscopic analysis coupled with quantum chemical calculations. Kadcoccitanes E-H were tested for their cytotoxic activities against five human tumor cell lines (HL-60, A-549, SMMC-7721, MDA-MB-231, SW-480) but none of them exhibited activities at the concentration 40 µM.

Cytotoxic C-20 non-oxygenated ent-kaurane diterpenoids from Isodon wardii.

Twenty new ent-kaurane diterpenoids, wardiisins A-T (1-20), along with two previously undescribed artefactual compounds (21 and 22) and twelve known analogues (23-34), were isolated from the aerial part of Isodon wardii. Their structures were elucidated by comprehensive analysis of spectroscopic data and single-crystal X-ray diffraction, and most of them were found to bear unusual C-12 oxygenation. Compounds 4, 7, 8, 19, 20, 21 exhibited remarkable cytotoxicity against the cancer cell lines HL-60, SMMC-7721, A-549, MDA-MB-231, and SW480, with IC50 values ranging from 0.3 to 5.2 µM. Moreover, 7 was found to induce G2/M cell cycle arrest and promote apoptosis in SW480 cell lines.

Dome-shaped mode lasing from liquid crystals for full-color lasers and high-sensitivity detection.

In this communication, we report a new class of oscillation mode, dome-shaped mode (DSM), in liquid crystal (LC) microlasers. A record high Q-factor over 24 000 is achieved in LC soft-matter microlasers. We successfully presented a proof-of-concept demonstration of red, green, blue (RGB) LC-DSM microlaser pixels with a 74% broader achievable color gamut than the standard RGB color space. Besides, the detection limit for acetone vapor molecules is as low as 0.5 ppm, confirming the excellent potential of the proposed LC-DSM microlaser in ultra-high sensitivity detection.