Enabling Carbonized Polymer Dots with Color-tunable Time-dependent Room Temperature Phosphorescence through Confining Carboxyl Dimer Association.

Developing a facile strategy to realize fine-tuning of phosphorescence color in time-dependent room temperature phosphorescence (RTP) materials is essential but both theoretically and practically rarely exploited. Through simultaneously confining carboxyl dimer association and isolated carboxyl into the particle via a simple hydrothermal treatment of polyacrylic acid, a dual-peak emission of red phosphorescence (645 nm) and green phosphorescence (550 nm) was observed from carbonized polymer dots (CPDs). The ratio of the two luminescent species can be well regulated by hydrochloric acid inhibiting the dissociation of carboxyl to promote hydrogen bond. Due to comparable but different lifetimes, color-tunable time-dependent RTP with color changing from yellow to green or orange to green were obtained. Based on the crosslinking enhanced emission effect, the phosphorescence visible time was even extended to 7 s through introducing polyethylenimide. This study not only proposes a novel and facile method for developing CPDs with color-tunable time-dependent RTP, but also provides a bran-new non-conjugated red phosphorescence unit and its definite structure.

Crosslink-Enhanced Emission-Dominated Design Strategy for Constructing Self-Protective Carbonized Polymer Dots With Near-Infrared Room-Temperature Phosphorescence.

Self-protective carbonized polymer dots (CPDs) with advantageous crosslinked nano-structures have attracted considerable attention in metal-free room temperature phosphorescence (RTP) materials, whereas their RTP emissions are still limited to short wavelength. Expanding their RTP emissions to Near-Infrared (NIR) range is attractive but suffers from the difficulties in constructing narrow energy levels and inhibiting intense non-radiative decay. Herein, a crosslink-enhanced emission (CEE)-dominated construction strategy was proposed, achieving desired NIR RTP (710 nm) in self-protective CPDs for the first time. Structural factors, i.e., crosslinking (covalent-bond CEE), conjugation (conjugated amine with bridging N-H and C=C group), and steric hindrance (confined-domain CEE), were confirmed indispensable for triggering NIR RTP emission in CPDs. Contrast experiments and theoretical calculations further revealed the rationality of the design strategy originating from CEE in terms of promoting the narrow energy level emission of triplet excitons and inhibiting the non-radiative quenching. This work not only firstly achieves NIR RTP in self-protective CPDs but also helps understand the origin of NIR RTP to further guide the synthesis of diverse CPDs with efficient long-wavelength RTP emission.

Baccaramiones A-D, Four Highly Oxygenated and Rearranged Trinorditerpenoids from Baccaurea ramiflora.

Baccaramiones A-D (1-4), four highly oxygenated and rearranged trinorditerpenoids, were isolated from Baccaurea ramiflora. Compound 1 is a 1(10 → 5)-abeo-15,16,17-trinor-ent-abietane featuring a unique 5/6/6 spirocyclic scaffold, and 2-4 are the first example of a novel 20(10 → 5)-abeo-15,16,17-trinor-ent-abietane skeleton. Their structures were established by spectroscopic analysis, X-ray crystallography, and electronic circular dichroism calculations. A plausible biosynthetic pathway for 1-4 was proposed. Interestingly, compounds 3 and 4 exhibited significant immunosuppressive activities against concanavalin A-induced T cell proliferation and lipopolysaccharide-induced B cell proliferation in vitro.

Phosphorus and Nitrogen Codoped Carbonized Polymer Dots with Multicolor Room Temperature Phosphorescence for Anticounterfeiting Painting.

Visible spectral afterglow materials offer unprecedented potential for a myriad of applications due to their long luminescence characteristics, but it is still insufficient to prepare matrix-free materials with multicolor afterglow including the blue color. In this study, we successfully developed phosphorus and nitrogen codoped carbonized polymer dots (CPDs) with multicolor room temperature phosphorescence (RTP) including the blue color by microwave-assisted chemical reactions under different reaction time. After ceasing UV light, all four prepared CPDs were able to emit vivid RTP with a maximum absolute phosphorescence quantum yield (QY) of 59.41% and a maximum lifetime of about 1 s (yellow CPDs). With the increase of microwave reaction time, the RTP color of CPDs showed a gradual blue shift from yellow to blue. The reason why the RTP color of CPDs showed a gradual blue shift was the decrease of C═O units as the extension of the microwave reaction time. In view of their fascinating multicolor RTP properties, potential applications of the four CPDs in the field of anticounterfeiting painting were presented and demonstrated. This work would inspire other researchers to enrich multicolor afterglow materials.

Behavioral responses of Platycladus orientalis plant volatiles to Phloeosinus aubei by GC-MS and HS-GC-IMS for discrimination of different invasive severity.

In recent years, the invasive cypress bark beetle (Phloeosinus aubei) has caused extensive damage to Platycladus orientalis plants in China, but its infestation is hard to monitor in the early stages. In this study, gas chromatography-mass spectrometry (GC-MS) was initially employed to investigate the volatile organic compound (VOC) emissions of P. aubei-infested P. orientalis saplings. The emissions of total sesquiterpenes were dominating (84-86% of total VOCs) and increased by 3.09-fold in P. aubei-damaged P. orientalis samples compared to undamaged samples, and the monoterpenes, aromatic compounds, and ketone emissions also had varying degrees of increase between 1.39-fold and 5.65-fold. Based on this variation, gas chromatography-ion mobility spectrometry (GC-IMS) was applied, as an untargeted analytical approach, to discriminate P. orientalis samples with different invasive severity. Two different features derived from GC-IMS data were adopted as the input information for classification and prediction models. Results showed that grid search support vector machine (GS-SVM) combined with multilinear principal component analysis (MPCA) based on spectral fingerprint achieved the best classification performances (> 88.98%), and partial least squares discriminant analysis (PLSR) method can accurately predict the pest numbers (R2 > 0.9423 and RMSE < 0.9827). In a word, the VOC profiling-based approach had the potential for evaluating P. aubei invasive severity and pest management.

Blockchain-Federated-Learning and Deep Learning Models for COVID-19 Detection Using CT Imaging.

With the increase of COVID-19 cases worldwide, an effective way is required to diagnose COVID-19 patients. The primary problem in diagnosing COVID-19 patients is the shortage and reliability of testing kits, due to the quick spread of the virus, medical practitioners are facing difficulty in identifying the positive cases. The second real-world problem is to share the data among the hospitals globally while keeping in view the privacy concerns of the organizations. Building a collaborative model and preserving privacy are the major concerns for training a global deep learning model. This paper proposes a framework that collects a small amount of data from different sources (various hospitals) and trains a global deep learning model using blockchain-based federated learning. Blockchain technology authenticates the data and federated learning trains the model globally while preserving the privacy of the organization. First, we propose a data normalization technique that deals with the heterogeneity of data as the data is gathered from different hospitals having different kinds of Computed Tomography (CT) scanners. Secondly, we use Capsule Network-based segmentation and classification to detect COVID-19 patients. Thirdly, we design a method that can collaboratively train a global model using blockchain technology with federated learning while preserving privacy. Additionally, we collected real-life COVID-19 patients' data open to the research community. The proposed framework can utilize up-to-date data which improves the recognition of CT images. Finally, we conducted comprehensive experiments to validate the proposed method. Our results demonstrate better performance for detecting COVID-19 patients.

Cephalodiones A-D: Compound Characterization and Semisynthesis by [6+6] Cycloaddition.

Cephalodiones A-D (1-4), the first example of C19 -norditerpenoid dimers, were isolated and fully characterized from a Cephalotaxus plant. These new skeletal natural products shared a unique tricyclo[6.4.1.12,7 ]tetradeca-3,5,9,11-tetraene-13,14-dione core that was capped in both ends with rigid multicyclic ring systems either C2 -symmetrically or asymmetrically. Compounds 1-4 were proposed to be biosynthetically produced by the [6+6]-cycloaddition of two identical C19 -norditerpenoid troponoids, which was validated by the semisyntheses of dimers 2-4. Moreover, some compounds showed significant inhibition on Th17 cell differentiation.

Crosslink-Enhanced Emission Effect on Luminescence in Polymers: Advances and Perspectives.

The crosslink-enhanced emission effect was first proposed to explore the strong luminescence of nonconjugated polymer dots possessing only either non-emissive or weakly emissive sub-luminophores. Interesting phenomena in recent research indicate such enhancement caused by extensive crosslinking appears in diverse luminescent polymers with sub-luminophores (electron-rich heteroatomic moieties) or luminophores (conjugated π domains). This enhancement can promote the emission from nonluminous to luminous, from weakly luminous to strongly luminous, and even convert the pathway of radiative transitions. The concept of the crosslink-enhanced emission effect should be updated and extended to an in-depth spatial effect, such as electron overlap and energy splitting in confined domains by effective crosslinking, more than initial immobilization. This Minireview outlines the development of the crosslink-enhanced emission effect from the perspective of the detailed classification, inherent mechanism and applicable systems. An outlook on the further exploration and application of this theory are also proposed.

Polycystic ovary syndrome is associated with anogenital distance, a marker of prenatal androgen exposure.

Study question: Is the presence of polycystic ovary syndrome (PCOS) associated with anogenital distance (AGD), a biomarker for the prenatal hormonal environment? Summary answer: The presence of PCOS is associated with longer AGD. What is known already: Although the aetiology of PCOS is unclear, emerging data suggest that the natural history of PCOS may originate from intrauterine life. Prenatal exposure to androgen hormones is considered an important factor of PCOS. AGD is the distance measured from the anus to the genital tubercle and there is considerable evidence in humans and animals to support AGD as a sensitive biomarker of prenatal androgen activity. Study design, size, duration: This case-control study of 156 PCOS patients and 180 reproductively healthy women (control subjects) was performed from October 2015 to July 2016. Participants/materials, setting, methods: The patients and controls were recruited from the out-patient Department of Gynecology of Sun Yat-sen Memorial Hospital. Participants completed health questionnaires and provided a blood sample for evaluation of serum reproductive hormone profiles. Anthropometric indices of AGDAF (anus-fourchette) and AGDAC (anus-clitoris) were measured in all subjects. We used logistic regression to estimate the association between the presence of PCOS and AGD measurements while accounting for important confounders, including age and BMI. Multiple linear regression was used to analyse the relationships between PCOS characteristics (e.g. polycystic ovaries and total testosterone (T)) and two measurements of AGD in the PCOS group and controls. Main results and the role of chance: Overall, logistic regression showed that women with AGDAF in the highest tertile were 18.8 times (95% CI 9.6-36.6; P < 0.001) more likely to have PCOS compared with those in the lowest tertile. Women with AGDAC in the highest tertile were 6.7 times (95% CI 3.7-12.1; P < 0.001) more likely to have PCOS than those in the lowest tertile. In the PCOS group, multiple linear regression analyses revealed that both AGD measurements were positively associated with T levels (ß = 0.246 for AGDAC, ß = 0.368 for AGDAF; P = 0.003 and P < 0.001, respectively), and AGDAF was positively associated with the presence of polycystic ovaries (ß = 0.279; P < 0.001). In the controls, a positive association was found only between T levels with AGDAF (ß = 0.177, P = 0.020), whereas no associations were found between the remaining covariates and AGD measurements. Limitations, reasons for caution: As this was an observational study, causal inference cannot be obtained. Wider implications of the findings: This study suggests that PCOS may originate in intrauterine life, and be affected by prenatal exposure to androgens. Study funding/competing interest(s): This study was supported by funds obtained from the Science Technology Research Project of Guangdong Province (2010B031600058 and 2015A030310083) and the Major Science Technology Research Project of Guangdong Province (ZKM05602S). The authors have no competing interests to declare. Trial registration number: Not applicable.

The prognostic value of the preoperative c-reactive protein/albumin ratio in ovarian cancer.

BACKGROUND: Inflammation plays an important role in the pathogenesis of ovarian cancer. This study sought to investigate the association between the preoperative c-reactive protein/albumin ratio (CRP/Alb) and oncological outcomes in ovarian cancer patients. METHODS: Two hundred patients with histologically verified ovarian cancer between June 2006 and July 2012 were retrospectively reviewed. Overall survival was evaluated by the Kaplan-Meier method and log-rank test. The significance of risk factors for overall survival was evaluated with the Cox proportional hazards model. Additionally, area under the receiver operating characteristic curve (AUC) was used to compare the predictive ability of CRP/Alb, Glasgow Prognostic Score (GPS), modified GPS (mGPS), neutrophil lymphocyte ratio (NLR), platelet lymphocyte ratio (PLR), prognostic index (PI) and prognostic nutritional index (PNI). RESULTS: The optimal cutoff value of CRP/Alb was 0.68. Increased CRP/Alb (≥0.68) was associated with advanced stage, residual tumor, ascites, elevated serum carbohydrate antigen(CA)-125 level, GPS, and mGPS (all p < 0.05). Patients with high CRP/Alb had poor overall survival compared to those with low CRP/Alb (p < 0.001). Multivariable analysis showed that CRP/Alb (Hazard Ratio (HR) 1.330, 95% confidence interval (CI) 1.131-1.564, p = 0.001), tumor stage (HR 1.577, 95% CI 1.189-2.091, p = 0.002), residual tumor (HR 2.337, 95% CI 1.518-3.597, p < 0.001) and age (HR 1.017, 95% CI 1.000-1.035, p = 0.046) were independent prognostic factors for overall survival. Additionally, the CRP/Alb showed greater AUC values at 1 year (0.692), 3 years (0.659), and 5 years (0.682) than GPS, mGPS and PNI. CONCLUSIONS: The CRP/Alb is a novel independent marker of poor prognosis among ovarian cancer patients and shows superior prognostic ability compared to the established inflammation-based prognostic indices.

[Investigation of the change of adiponectin level with menopause status in middle aged women and its relationship with androgen].

OBJECTIVE: To investigate the change of adiponectin level with menopause status in women aged 40 to 65, and its relationship with androgen. METHODS: A cross-sectional study included woman (aged from 40 to 65) who were in hospital for routine check-up at the Sun Yat-sen Memorial Hospital from August to October in 2013. All subjects underwent laboratory examinations of adiponectin, sex hormone binding globulin (SHBG), dehydroepiandrosterone-sulfate (DHEA-S), total testosterone (TT), collected anthropometric measurements and then calculated free androgen index (FAI) and body mass index (BMI). According to their menstrual status, the subjects were divided into 4 groups: premenopausal group with 119 subjects, perimenopausal group with 60 subjects, early postmenopausal group with 62 subjects, late postmenopausal group with 64 subjects. RESULTS: (1) Adiponectin levels declined to its lowest level in menopausal transition and gradually becoming higher after menopause, which showed a U-shaped trajectory. When compared adiponectin levels in late postmenopausal group [(13 ± 5) mg/L] with those in perimenopausal [(8 ± 6) mg/L] or early postmenopausal group [(9 ± 6) mg/L], it all showed significantly difference (P < 0.05). (2) Both the adiponectin levels were negatively correlated with waistline in the 4 groups (premenopausal group, r = -0.276; perimenopausal group, r = -0.334; early postmenopausal group, r = -0.211; late postmenopausal group, r = -0.218; all P < 0.05). Levels of adiponectin were positively correlated with SHBG (r = 0.536, P < 0.05) and negatively with FAI (r = -0.363, P < 0.05) in menopausal transition, while in late postmenopausal group, negatively correlated with level of DHEA-S (r = -0.450, P < 0.05). When adjusted for age, BMI and waistline, the above correlations still exist. CONCLUSIONS: Adiponectin levels declined to its lowest level in menopausal transition and gradually becoming higher after menopause, which showed a U-shaped trajectory during the sequential menopause status transition in middle aged women. Low level of adiponectin in menopausal transition is closely associated with the relative excess androgen occurred during this stage.

Exploration of tumor-suppressive microRNAs silenced by DNA hypermethylation in cervical cancer.

BACKGROUND: Multiple studies proved that miRNAs have a causal role in tumorigenesis. Some miRNAs are regulated by epigenetic alterations in their promoter regions and can be activated by chromatin- modifying drugs. METHODS: We treated cervical cancer cells with 5-aza-2'-deoxycytidine and get a microarray analysis. Dysregulation of miRNAs was measured by qPCR in cervical cell lines and methylation status of them in cervical cancer tissue were performed with MeDIP-qPCR assay. RESULTS: We found hypermethylation of miR-432, miR-1286, miR-641, miR-1290, miR-1287 and miR-95 may have some relationship with HPV infection in cervical cell lines. In primary tumors of cervix with paired normal tissue, expression levels of miRNAs were inversely correlated with their DNA methylation status in the cervical cancer cell lines treated with 5-AZA. CONCLUSIONS: Our results indicate that miRNAs might play a role in the pathogenesis of human cervical cancer with HPV and identify altered miRNA methylation as a possible epigenetic mechanism involved in their aberrant expression.

Allylic hydroxylation of enones useful for the functionalization of relevant drugs and natural products.

Enones are privileged structural motifs in bioactive natural products and pharmaceuticals, but the γ-hydroxylation of enones is challenging. Here we show a mild and efficient method for the direct C(sp3)-H hydroxylation of enones via visible-light-induced hydrogen-atom transfer (HAT), which facilitates γ-hydroxylation of primary, secondary, and tertiary C-H bonds of different enones without involving metal and peroxide. The mechanism study shows that Na2-eosin Y serves as both the photocatalyst and the source of catalytic bromine radical species in the HAT-based catalytic cycle, and finally sacrifices itself completely by oxidative degradation to produce bromine radical and a major product phthalic anhydride in an environmentally friendly way. This scalable method was demonstrated by plenty of substrates (41 examples) including 10 clinical drugs and 15 natural products to be useful for the late-stage functionalization of enone-containing compounds, and, in particular, has potential application in industry for large-scale production.

Challenges and applications of volatile organic compounds monitoring technology in plant disease diagnosis.

Biotic and abiotic stresses are well known to increase the emission of volatile organic compounds (VOCs) from plants. The analysis of VOCs emissions from plants enables timely diagnostic of plant diseases, which is critical for prompting sustainable agriculture. Previous studies have predominantly focused on the utilization of commercially available devices, such as electronic noses, for diagnosing plant diseases. However, recent advancements in nanomaterials research have significantly contributed to the development of novel VOCs sensors featuring exceptional sensitivity and selectivity. This comprehensive review presents a systematic analysis of VOCs monitoring technologies for plant diseases diagnosis, providing insights into their distinct advantages and limitations. Special emphasis is placed on custom-made VOCs sensors, with detailed discussions on their design, working principles, and detection performance. It is noteworthy that the application of VOCs monitoring technologies in the diagnostic process of plant diseases is still in its emerging stage, and several critical challenges demand attention and improvement. Specifically, the identification of specific stress factors using a single VOC sensor remains a formidable task, while environmental factors like humidity can potentially interfere with sensor readings, leading to inaccuracies. Future advancements should primarily focus on addressing these challenges to enhance the overall efficacy and reliability of VOCs monitoring technologies in the field of plant disease diagnosis.

Unprecedented sesterterpenoids, orientanoids A-C: discovery, bioinspired total synthesis and antitumor immunity.

Sesterterpenoids are a very rare class of important natural products. Three new skeletal spiro sesterterpenoids, named orientanoids A-C (1-3), were isolated from Hedyosmum orientale. Their structures were determined by a combination of spectroscopic data, X-ray crystallography, and total synthesis. To obtain adequate materials for biological research, the bioinspired total syntheses of 1-3 were effectively achieved in 7-8 steps in overall yields of 2.3-6.4% from the commercially available santonin without using any protecting groups. In addition, this work also revised the stereochemistry of hedyosumins B (6) and C (10) as 11R-configuration. Tumor-associated macrophages (TAMs) have emerged as important therapeutic targets in cancer therapy. The in-depth biological evaluation revealed that these sesterterpenoids antagonized the protumoral and immunosuppressive functional phenotype of macrophages in vitro. Among them, the most potent and major compound 1 inhibited protumoral M2-like macrophages and activated cytotoxic CD8+ T cells, and consequently inhibited tumor growth in vivo.

ASFL-YOLOX: an adaptive spatial feature fusion and lightweight detection method for insect pests of the Papilionidae family.

Introduction: Insect pests from the family Papilionidae (IPPs) are a seasonal threat to citrus orchards, causing damage to young leaves, affecting canopy formation and fruiting. Existing pest detection models used by orchard plant protection equipment lack a balance between inference speed and accuracy. Methods: To address this issue, we propose an adaptive spatial feature fusion and lightweight detection model for IPPs, called ASFL-YOLOX. Our model includes several optimizations, such as the use of the Tanh-Softplus activation function, integration of the efficient channel attention mechanism, adoption of the adaptive spatial feature fusion module, and implementation of the soft Dlou non-maximum suppression algorithm. We also propose a structured pruning curation technique to eliminate unnecessary connections and network parameters. Results: Experimental results demonstrate that ASFL-YOLOX outperforms previous models in terms of inference speed and accuracy. Our model shows an increase in inference speed by 29 FPS compared to YOLOv7-x, a higher mAP of approximately 10% than YOLOv7-tiny, and a faster inference frame rate on embedded platforms compared to SSD300 and Faster R-CNN. We compressed the model parameters of ASFL-YOLOX by 88.97%, reducing the number of floating point operations per second from 141.90G to 30.87G while achieving an mAP higher than 95%. Discussion: Our model can accurately and quickly detect fruit tree pest stress in unstructured orchards and is suitable for transplantation to embedded systems. This can provide technical support for pest identification and localization systems for orchard plant protection equipment.

Confined-domain crosslink-enhanced emission effect in carbonized polymer dots.

Revealing the photoluminescence (PL) origin and mechanism is a most vital but challenging topic of carbon dots. Herein, confined-domain crosslink-enhanced emission (CEE) effect was first studied by a well-designed model system of carbonized polymer dots (CPDs), serving as an important supplement to CEE in the aspect of spatial interactions. The "addition-condensation polymerization" strategy was adopted to construct CPDs with substituents exerting different degrees of steric hindrance. The effect of confined-domain CEE on the structure and luminescence properties of CPDs have been systematically investigated by combining characterizations and theoretical calculations. Such tunable spatial interactions dominated the coupling strength of the luminophores in one particle, and eventually resulted in the modulated PL properties of CPDs. These findings provide insights into the structural advantages and the PL mechanism of CPDs, which are of general significance to the further development of CPDs with tailored properties.

Neuromuscular electrical stimulation and biofeedback therapy may improve endometrial growth for patients with thin endometrium during frozen-thawed embryo transfer: a preliminary report.

BACKGROUND: To investigate the effect of pelvic floor Neuromuscular Electrical Stimulation (NMES) Therapy in improving endometrial thickness in women with thin endometrium. METHODS: 41 patients undergoing assisted reproduction with a thin endometrium (less than or equal to7 mm) were recruited and advised to go for a pelvic floor NMES in frozen-thawed embryo transfer cycle. PHENIX Neuromuscular Electrical Stimulation Therapy System was used according to the manufacturer's recommended protocol for 20 to 30 minutes of intermittent vaginal electrical stimulation on the treatment days. RESULTS: A total of 20 and 21 were included in the NMES and non-NMES groups respectively. 12 out of 20 (60%) patients developed endometrial thickness equal to or more than 8 mm after the NMES therapy, which was the primary outcome. The mean thickness of endometrium before and after was respectively 5.60 mm (0.82 mm) and 7.93 mm (1.42 mm) in the therapy group versus 5.50 mm (1.00) and 6.78 mm (0.47) in the control group; the difference was statistically significant (P = 0.002). There was higher pregnancy rate in the NMES group (42% versus 35%) but the difference was not statistically significant. CONCLUSION: Neuromuscular Electrical stimulation therapy may be effective for the patients with a thin endometrium. Further studies are needed to investigate its effectiveness.

Nanoporous Functionalized WS2/MWCNTs Nanocomposite for Trimethylamine Detection Based on Quartz Crystal Microbalance Gas Sensor.

We have developed a tungsten disulfide (WS2)/multiwall carbon nanotubes (MWCNTs) nanocomposite based QCM gas sensor for (trimethylamine) TMA gas sensing of low concentrations. WS2/MWCNTs nanocomposite was synthesized via the hydrothermal method and was characterized for surface morphology, nanostructure, thermal stability, and elementary composition. The TMA-sensing properties of WS2/MWCNTs nanocomposite based QCM sensor were investigated. The composite based QCM sensor showed faster response time, strong response amplitude, good gas capacity, and good selectivity and stability compared with as prepared WS2 and MWCNTs-1 based QCM sensor. The response time of WS2/MWCNTs based QCM sensor was 294.1 and 142.9 s shorter than WS2 and MWCNTs-1 for 500 ppb TMA gas. And the response of the WS2/MWCNTs based QCM sensor was almost stable over 40 days, and the limit of detection (LOD) was 76 ppb calculated by the ICH method. This was ascribed to the fact that MWCNTs provided a skeleton for the growth of WS2 nanosheets and avoided agglomeration. The special structure could not only improve the structure ability but also expose more active adsorption sites. In order to further investigate the adsorption mechanism of the TMA molecule on (pure/functionalized) WS2 materials, density functional theory (DFT) calculations based on first-principle were conducted in the Vienna Ab-initio Simulation Package under ideal conditions.

Discovery of four modified classes of triterpenoids delineated a metabolic cascade: compound characterization and biomimetic synthesis.

Chemical studies on Dichapetalum gelonioides have afforded 18 highly modified complex triterpenoids belonging to four compound classes as defined by the newly adapted functional motifs associated with the A ring of the molecules. Their structures were determined by solid data acquired by diverse methods. The biosynthetic pathway for the four compound classes was rationalized via cascade modifications involving diverse chemical events. The subsequent biomimetic syntheses afforded all the desired products, including compounds 16 and 19 that were not obtained in our purification, which validated the proposed biosynthetic pathway. Besides, some compounds exhibited strong cytotoxic activities, especially 2 and 4 showed nanomolar potency against the NAMALWA tumor cell line, and a gross structure-activity relationship (SAR) of these compounds against the tested tumor cell lines was delineated.