Transcatheter arterial chemoembolisation combined with lenvatinib and cabozantinib in the treatment of advanced hepatocellular carcinoma.

OBJECTIVE: The objective of this study was to evaluate the effect and prognosis of transcatheter arterial chemoembolisation (TACE) combined with lenvatinib and cabozantinib in the treatment of advanced unresectable hepatocellular carcinoma (uHCC) and identify the predictors of prognosis related to cellular inflammation and body mass index (BMI). To the best of our knowledge, this is the first study to report the efficacy and prognosis of TACE combined with lenvatinib and cabozantinib in patients with uHCC and propose the neutrophil-to-lymphocyte ratio (NLR) and the platelet-to-lymphocyte ratio (PLR) as predictors of response and survival outcomes in this context. METHODS: The clinicopathologic data of 217 patients with advanced uHCC who underwent TACE combined with systemic therapy (lenvatinib mesylate + cabozantinib) in the Department of Hepatobiliary Surgery, Dazhou Central Hospital between October 2017 and February 2020 were collected retrospectively, and the relevant parameters were analysed and compared. RESULTS: Univariate and multivariate logistic regression analyses showed that BMI, NLR, PLR and prothrombin time were independent factors for the objective response rate (ORR) of transformed therapy for uHCC (OR = 0.812 vs 1,290.68 vs 1.067 vs 0.626, 95 % CI: 0.719-0.897 vs 108.081-11,541.137 vs 1.037-1.099 vs 0.414-0.946, respectively, p < 0.05). The results showed that BMI, NLR and PLR had certain predictive values for the ORR in patients with liver cancer undergoing translational therapy (p < 0.05); the combined predictive effect of the three was the best, and the area under the curve (AUC) of BMI + NLR + PLR for predicting the ORR in patients with liver cancer undergoing translational therapy was 0.951 (95 % CI: 0.921, 0.964). A total of 181 patients experienced adverse reactions at different grades, including 104 cases at grade 1, 50 cases at grade 2, 22 cases at grade 3 and 5 cases at grade 4. There was a significant difference in overall survival (OS) between low- and high-NLR groups, low- and high-PLR groups and low- and high-BMI groups (χ2 = 9.644, 8.313 and 10.314, respectively, p < 0.05). There was a significant difference in progression-free survival (PFS) between the low- and high-NLR groups, the low- and high-PLR groups and the low- and high-BMI groups (χ2 = 8.965, 9.783 and 6.343, respectively, p < 0.05). CONCLUSION: Transcatheter arterial chemoembolisation combined with lenvatinib and cabozantinib is safe and effective in the treatment of advanced uHCC, with controllable adverse reactions. High NLR and PLR and low BMI values before treatment were independent risk factors for the ORR. Body mass index, NLR and PLR predicted responses to triple switch therapy and survival outcomes in uHCC. Patients with pretreatment NLR ≥ 2.96 and PLR ≥ 184.41 had worse OS and PFS rates. Patients with pretreatment BMI ≥ 23 kg/m2 had improved OS and a reduced risk of death.

Multidimensional Transcriptomics Unveils RNF34 as a Prognostic Biomarker and Potential Indicator of Chemotherapy Sensitivity in Wilms' Tumour.

Nephroblastoma, colloquially known as Wilms' tumour (WT), is the predominant malignant renal neoplasm arising in the paediatric population. Modern therapeutic approaches for WT incorporate a synergistic combination of surgical intervention, radiotherapy, and chemotherapy, which substantially ameliorate the overall patient survival rate. Despite this, the optimal sequence of chemotherapy and surgical intervention remains a matter of contention, with each strategy presenting its own strengths and weaknesses that could influence clinical decision-making. To make some headway on this clinical dilemma, we deployed a multidimensional transcriptomics integration approach by analysing bulk RNA sequencing data with 136 samples, as well as single-nucleus RNA sequencing (snRNA-seq) and paired spatial transcriptome sequencing (stRNA) data from 32 WT specimens. Our findings identified a distinct elevation of RNF34 expression within WT samples, which correlated with unfavourable prognostic outcomes. Leveraging the Genomics of Drug Sensitivity in Cancer (GDSC), we simultaneously revealed that patients with high expression of RNF34 have higher sensitivity to commonly used chemotherapy drugs for WT. Furthermore, our analysis of snRNA and stRNA data unveiled a reduced proportion of RNF34 expression in neoplastic cells after chemotherapy. Moreover, stRNA data delineated a significant association between a higher proportion of RNF34 expression in cancer cells and adverse features such as anaplastic histology and tumour recurrence. Intriguingly, we also observed a close association between elevated RNF34 expression and a characteristic exhausted tumour immune microenvironment. Collectively, our findings underscore the pivotal role of RNF34 in the prognostic prediction potential and treatment sensitivity of WT. This comprehensive analysis can potentially inform and refine clinical decision-making for WT patients and guide future studies towards the development of optimized, rational therapeutic strategies.

Biomimetic Injectable Hydrogel Based on Methacrylate-Modified Silk Fibroin Embedded with Kartogenin for Superficial Cartilage Regeneration.

The weak regeneration ability of chondrocytes is one of the main reasons that limit the therapeutic effect of clinical cartilage injury. Injectable hydrogels are potential scaffolds for cartilage tissue engineering with advantages such as minimally invasive surgery, porous structure, and drug sustained-release ability. At present, many biomaterials have been developed for the repair of deep cartilage defects. However, cartilage injury often begins on the surface, which requires us to propose a treatment strategy suitable for superficial cartilage injury repair. In this study, we fabricated a biomimetic injectable hydrogel based on methacrylate-modified silk fibroin (SilMA) embedded with kartogenin (KGN). The SilMA/KGN hydrogels have good biohistocompatibility and the ability to promote cartilage differentiation. In addition, SEM results show that it has a porous structure conducive to cell adhesion and proliferation. Most importantly, it has demonstrated remarkable superficial cartilage repair ability in vivo, showing potential in cartilage tissue engineering.

Unveiling the hidden AP-1: revealing the crucial role of AP-1 in ccRCC at single-cell resolution.

Clear cell renal cell carcinoma (ccRCC), as the most common histological subtype of kidney cancer, has been reported to originate primarily from proximal tubule (PT) cells in the kidney. However, the current research on its associated molecular mechanisms remains relatively limited. In our study, we analyzed multiple single-cell multi-omics datasets obtained from various research teams, revealing the significant role of the activator protein 1 (AP-1) in ccRCC tumorigenesis. The motif activity analysis of transcription factors (TFs) showed a predominant activation of AP-1 in ccRCC cancer cells compared to PT cells. Furthermore, our findings at single-cell resolution revealed a notable absence of AP-1 expression in PT cells when compared to ccRCC cancer cells. In bulk-RNA of discovery cohort, no differential expression of AP-1 was detected in normal kidney and ccRCC samples, which may be attributed to confounding effects in bulk-RNA sequencing. Meanwhile, spatial transcriptomics analysis demonstrated a broader expression range of the AP-1 compared to the ccRCC marker CA9. Moreover, we observed chromatin accessibility of the AP-1 in various cell-types, including PT cells, suggesting that the transcriptional expression of AP-1 in PT cells may be influenced by subsequent transcriptional modifications, reflecting the complex regulatory mechanism of AP-1 transcription. These findings provide important insights for a deeper understanding of the function and regulatory mechanisms of AP-1 in ccRCC, thereby establishing a theoretical foundation for future clinical research and the development of treatment strategies.

Unraveling the enigma of B cells in diffuse large B-cell lymphoma: unveiling cancer stem cell-like B cell subpopulation at single-cell resolution.

Background: Diffuse large B-cell lymphoma (DLBCL) represents the most prevalent form of aggressive non-Hodgkin lymphoma. Despite receiving standard treatment, a subset of patients undergoes refractory or recurrent cases, wherein the involvement of cancer stem cells (CSCs) could be significant. Methods: We comprehensively characterized B cell subpopulations using single-cell RNA sequencing data from three DLBCL samples and one normal lymph tissue. The CopyKat R package was employed to assess the malignancy of B cell subpopulations based on chromosomal copy number variations. CIBERSORTx software was utilized to estimate the proportions of B cell subpopulations in 230 DLBCL tissues. Furthermore, we employed the pySCENIC to identify key transcription factors that regulate the functionality of B cell subpopulations. By employing CellphoneDB, we elucidated the interplay among tumor microenvironment components within the B cell subpopulations. Finally, we validated our findings through immunofluorescence experiments. Results: Our analysis revealed a specific cancer stem cell-like B cell subpopulation exhibiting self-renewal and multilineage differentiation capabilities based on the exploration of B cell subpopulations in DLBCL and normal lymph tissues at the single-cell level. Notably, a high infiltration of cancer stem cell-like B cells correlated with a poor prognosis, potentially due to immune evasion mediated by low expression of major histocompatibility complex molecules. Furthermore, we identified key transcription factor regulatory networks regulated by HMGB3, SAP30, and E2F8, which likely played crucial roles in the functional characterization of the cancer stem cell-like B cell subpopulation. The existence of cancer stem cell-like B cells in DLBCL was validated through immunofluorescent staining. Finally, cell communication between B cells and tumor-infiltrating T cell subgroups provided further insights into the functional characterization of the cancer stem cell-like B cell subpopulation. Conclusions: Our research provides a systematic description of a specific cancer stem cell-like B cell subpopulation associated with a poor prognosis in DLBCL. This study enhances our understanding of CSCs and identifies potential therapeutic targets for refractory or recurrent DLBCL patients.

A multi-functional double cross-linked chitosan hydrogel with tunable mechanical and antibacterial properties for skin wound dressing.

Chitosan hydrogels with essential antibacterial properties and biocompatibility have great potential in tissue engineering and regeneration medicine. However, pure chitosan hydrogel could be limited by insufficient mechanical properties. In this work, we designed a multi-functional chitosan hydrogel based on the combination of chitosan methacrylate (CTSMA) and sulfhydrated chitosan (CTSSH), which is cross-linked simultaneously by free-radical polymerization reaction and Thiol-ene reaction. The CTSMA/CTSSH (CMS) hydrogels displayed superior tissue adhesive and mechanical properties when compared to pure CTSMA hydrogel. Additionally, the resulting hydrogels exhibited potent antimicrobial effects against both E. coli and S. aureus. Besides, the CMS hydrogels exhibited good biocompatibility as demonstrated by cytotoxicity and cell proliferation experiments using fibroblasts cells (L929) and adipose-derived stem cells (ADSCs). In vivo experiment, the repairing effect of hydrogels on full-thickness skin defect model in rats was studied. Histological and immunohistochemical staining results showed that CMS hydrogels promoted angiogenesis, dermal repair and epidermal regeneration. Overall, the study highlights the potential of the CMS hydrogels as a promising biomaterial in wound healing applications.

Discovery of Novel Fedratinib-Based HDAC/JAK/BRD4 Triple Inhibitors with Remarkable Antitumor Activity against Triple Negative Breast Cancer.

Multitarget HDAC inhibitors capable of simultaneously blocking the BRD4-LIFR-JAK1-STAT3 signaling pathway hold great potential for the treatment of TNBC and other solid tumors. Herein, novel Fedratinib-based multitarget HDAC inhibitors were rationally designed, synthesized, and biologically evaluated, among which compound 25ap stood out as a potent HDAC/JAK/BRD4 triple inhibitor. Satisfyingly, compound 25ap led to concurrent inhibition of HDACs and the BRD4-LIFR-JAK1-STAT3 signaling pathway, which was validated by hyper-acetylation of histone and α-tubulin, hypo-phosphorylation of STAT3, downregulation of LIFR, MCL-1, and c-Myc in MDA-MB-231 cells. The multitarget effects of 25ap contributed to its robust antitumor response, including potent antiproliferative activity, remarkable apoptosis-inducing activity, and inhibition of colony formation. Notably, 25ap possessed an acceptable therapeutic window between normal and cancerous cells, desirable in vitro metabolic stability in mouse microsome, and sufficient in vivo exposure via intraperitoneal administration. Additionally, the in vivo antitumor potency of 25ap was demonstrated in an MDA-MB-231 xenograft model.

Revisiting matrix hydrogel composed of gelatin and hyaluronic acid and its application in cartilage regeneration.

With the increasing incidence of knee osteoarthritis (KOA), the reparation of cartilage defects is gaining more attention. Given that tissue integration plays a critical role in repairing cartilage defects, tissue adhesive hydrogels are highly needed in clinics. We constructed a biomacromolecule-based bioadhesive matrix hydrogel and applied it to promote cartilage regeneration. The hydrogel was composed of methacrylate gelatin and N-(2-aminoethyl)-4-(4-(hydroxymethyl)-2-methoxy-5-nitroso) butyl amide modified hyaluronic acid (HANB). The methacrylate gelatin provided a stable hydrogel network as a scaffold, and the HANB served as a tissue-adhesive agent and could be favorable for the chondrogenesis of stem cells. Additionally, the chemically modified HA increased the swelling ratio and compressive modulus of the hydrogels. The results of our in vitro study revealed that the hydrogel was compatible with bone marrow stromal cells. In vivo, the hyaluronic-acid-containing hydrogels were found to promote articular cartilage regeneration in the defect site. Therefore, this biomaterial provides promising potential for cartilage repair.

Discovery of the First Irreversible HDAC6 Isoform Selective Inhibitor with Potent Anti-Multiple Myeloma Activity.

In our previous research, a series of phenylsulfonylfuroxan-based hydroxamates were developed, among which compound 1 exhibited remarkable in vitro and in vivo antitumor potency due to its histone deacetylase (HDAC) inhibitory and nitric oxide (NO)-donating activities. Herein, the in-depth study of compound 1 revealed that this HDAC inhibitor-NO donor hybrid could enduringly increase the intracellular levels of acetyl histones and acetyl α-tubulin, which could be ascribed to its irreversible inhibition toward class I HDACs and HDAC6. Structural modification of compound 1 led to a novel phenylsulfonylfuroxan-based hydroxamate 4, which exhibited considerable HDAC6 inhibitory activity and selectivity. Furthermore, compound 4 could inhibit intracellular HDAC6 both selectively and irreversibly. To the best of our knowledge, this is the first research reporting the irreversible inhibition of HDAC6. It was also demonstrated that compared with ACY-241 (a reversible HDAC6 inhibitor in clinical trials), the irreversible HDAC6 selective inhibitor 4 exhibited not only superior anti-multiple myeloma activity but also improved therapeutic index.

Synthesis-accessibility-oriented design of c-Jun N-terminal kinase 1 inhibitor.

Idiopathic pulmonary fibrosis (IPF) is a severe and progressive lung disease with poor prognosis and limited treatment options. The c-Jun N-Terminal Kinase 1 (JNK1), a key component of the MAPK pathway, has been implicated in the pathogenesis of IPF and represents a potential therapeutic target. However, the development of JNK1 inhibitors has been slowed, partly due to synthetic complexity in medicinal chemistry modification. Here, we report a synthesis-accessibility-oriented strategy for designing JNK1 inhibitors based on computational prediction of synthetic feasibility and fragment-based molecule generation. This strategy led to the discovery of several potent JNK1 inhibitors, such as compound C6 (IC50 = 33.5 nM), which exhibited comparable activity to the clinical candidate CC-90001 (IC50 = 24.4 nM). The anti-fibrotic effect of C6 was further confirmed in animal model of pulmonary fibrosis. Moreover, compound C6 could be synthesized in only two steps, compared to nine steps for CC-90001. Our findings suggest that compound C6 is a promising lead for further optimization and development as a novel anti-fibrotic agent targeting JNK1. In addition, the discovery of C6 also demonstrates the feasibility of synthesis-accessibility-oriented strategy in lead discovery.

An adhesive gelatin-coated small intestinal submucosa composite hydrogel dressing aids wound healing.

It is a challenging clinical task to determine how to repair large-area skin defects better. Traditional wound dressings (e.g., cotton and gauze) can only be used as a dressing; consequently, there is an increasing demand for wound dressings with additional properties (i.e., antibacterial and pro-repair) in clinical practice. In this study, a composite hydrogel with o-nitrobenzene-modified gelatin-coated decellularized small intestinal submucosa (GelNB@SIS) was designed for the repair of skin injuries. SIS is a natural extracellular matrix with a 3D microporous structure and also contains high levels of growth factors and collagen. GelNB provides this material photo-triggering tissue adhesive property. The structure, tissue adhesion, cytotoxicity, and bioactivity to cells were investigated. Based on in vivo study and histological analysis, we found the combination of GelNB and SIS improved the healing process by promoting vascular renewal, dermal remodeling, and epidermal regeneration. Based on our findings, GelNB@SIS is a promising candidate for tissue repair applications.

Involvement of ZDHHC9 in lung adenocarcinoma: regulation of PD-L1 stability via palmitoylation.

Palmitoylation is a post-translational modification occurring on cysteine residues, which process is catalyzed by a family of zinc finger Asp-His-His-Cys (DHHC) domain-containing (ZDHHC) protein acyltransferases. As a family member, ZDHHC9 plays a crucial role in varied malignancies by regulating protein stability via protein substrate palmitoylation. Based on the bioinformatic analysis of GEO gene microarray GSE75037 (|log2 fold change|> 1, P < 0.05), ZDHHC9 was defined as a significantly upregulated gene in lung adenocarcinoma (LUAD), which was also confirmed in our collected clinical specimens. It is necessary to explore the biological function of ZDHHC9 in LUAD cells. The follow-up functional experiments revealed that ZDHHC9 deficiency inhibited proliferation, migration, and invasion, while stimulated apoptosis in HCC827 cells. Besides, these malignant phenotypes could be accelerated by ZDHHC9 overexpression in A549. Moreover, we revealed that ZDHHC9 knockdown could promote PD-L1 protein degradation by reducing its palmitoylation level. The reduction of PD-L1 protein level could enhance anti-tumor immunity and inhibit the growth of LUAD cells. Therefore, our study uncovers the tumor-promoting role of ZDHHC9 in LUAD via regulating PD-L1 stability through palmitoylation, highlighting ZDHHC9 as a novel therapeutic target for LUAD.

Myelin and lymphocyte protein serves as a prognostic biomarker and is closely associated with the tumor microenvironment in the nephroblastoma.

Nephroblastoma, also known as Wilms' tumor (WT), is the most common renal tumor that occurs in children. Although the efficacy of treatment has been significantly improved by a series of comprehensive treatments, some patients still have poor prognosis. Myelin and lymphocyte (MAL) protein, a highly hydrophobic integrated membrane-bound protein, has been implicated in many tumors and is also closely linked to kidney development. However, the relationship between MAL and WT has not yet been elucidated. Therefore, we attempted to evaluate the feasibility of MAL as a promising prognosis factor for WT. The differential expression of MAL was investigated using TARGET database and was verified using the Gene Expression Omnibus database and real-time quantitative PCR. The prognostic ability of MAL was determined using Kaplan-Meier and Cox regression analyses. Pearson correlation analysis was applied to explore the relationship between MAL expression and methylation sites. The ESTIMATE and CIBERSORT algorithms showed that MAL expression was associated with the WT tumor microenvironment. Gene Set Enrichment Analysis (GSEA) indicated that multiple signaling pathways closely associated with tumorigenesis were differentially enriched between the high- and low-MAL groups. In conclusion, our study comprehensively explored the potential of MAL as a prognosis factor for WT. Meanwhile, we also demonstrated that MAL, as a prognostic factor for WT, may be closely related to the tumor microenvironment.

A Novel Autophagy-Related Marker for Improved Differential Diagnosis of Rheumatoid Arthritis and Osteoarthritis.

Rheumatoid arthritis (RA) and osteoarthritis (OA) are two most common rheumatic diseases in the world. Although there are standard methods for the diagnosis of both RA and OA, the differentials in some cases are poor. With deepening research, the role of autophagy in maintaining cell homeostasis and thus enabling cells adapt to external environments has become increasingly prominent. Both RA and OA, two diseases with inherent differences in pathogenesis, gradually show differences in autophagy levels. Our study therefore aims to further understand differences in pathogenesis of RA and OA through in-depth studies of autophagy in RA and OA. We also define appropriate autophagy-related markers as recognition indicators. Differences in autophagy levels between RA and OA were found based on analysis of the Kyoto Encyclopedia of Genes and Genomes (KEGG) and single-sample gene set enrichment (ssGSEA). These differences were mainly caused by 134 differentially expressed genes (DEGs). In two autophagy-related genes, CXCR4 and SERPINA1, there existed significant statistical difference between RA and OA. An autophagy related index (ARI) was thus successfully constructed based on CXCR4 and SERPINA by binary logistic regression of the generalized linear regression (GLR) algorithm. Pearson analysis indicated that the expression of CXCR4, SERPINA1, and ARI were closely correlated with autophagy scores and immune infiltration. Moreover, ARI showed high disease identification through receiver operating characteristic (ROC) analysis (AUCtesting cohort = 0.956, AUCtraining cohort = 0.867). These results were then verified in GSE12021 independent cohort. In conclusion, ARI associated with autophagy and immune infiltration was successfully constructed for accurately identifying OA and RA. The index, thus, has great potential in clinical applications.

The Prognostic Value of Baseline Distant Metastasis in Icotinib-Treated Patients with EGFR-Mutated Stage IV Non-Small Cell Lung Cancer.

PURPOSE: Several studies have revealed the prognostic value distant metastasis in non-small-cell lung cancer (NSCLC) patients receiving first-line epidermal growth factor receptor (EGFR) inhibitors. However, the question of whether the specific metastatic site could predict survival outcomes remain elusive. This study evaluated the prognostic value of specific metastatic site at diagnosis in first-line icotinib-treated patients with EGFR-mutated advanced NSCLC. METHODS: A total of 216 patients with EGFR-mutated stage IV NSCLC who received first-line icotinib treatment were retrospectively enrolled. The associations between the presence of distant metastasis to certain organs at diagnosis and survival outcomes were analyzed. PATIENTS AND METHODS: The presence of distant metastases was not associated with progression-free survival. Patients with liver metastasis showed a significantly shorter OS than those without liver metastasis (14.6m vs 33.0m, p=0.024). Patients with brain metastasis showed a marginally shorter OS than those without brain metastasis (26.5m vs 33.8m, p=0.051). Patients with lung metastasis showed a significantly longer OS than those without lung metastasis (36.0m vs 28.6m, p=0.038). Multivariable Cox regression analysis showed the presence of liver metastasis (HR [hazard ratio]: 2.265, 95% CI [confidence interval]: 1.239-4.139, p=0.008) and brain metastasis (HR: 1.493, 95% CI: 1.012-2.202, p=0.043) were independent predictors for unfavorable OS, while lung metastasis (HR: 0.669, 95% CI: 0.460-0.971, p=0.034) was an independent predictor for favorable OS. CONCLUSION: The presence of liver and brain metastasis predicted unfavorable OS, while the presence of lung metastasis predicted favorable OS in first-line icotinib-treated patients with EGFR-mutated stage IV NSCLC.

Monoclinic dibismuth tetraoxide (m-Bi2O4) for piezocatalysis: new use for neglected materials.

Piezocatalysis is a promising approach for environmental pollutant removal. Monoclinic dibismuth tetraoxide (m-Bi2O4) was first applied to piezocatalyze organics under ultrasonic vibration. The built-in electric field with ultrasonic stress drives the separation of holes and electrons in m-Bi2O4. Its excellent piezocatalytic activity, reusability and chemical stability make m-Bi2O4 a new candidate of piezocatalysis.

Development of an immune-related gene pairs index for the prognosis analysis of metastatic melanoma.

Melanoma is a skin cancer with great metastatic potential, which is responsible for the major deaths in skin cancer. Although the prognosis of melanoma patients has been improved with the comprehensive treatment, for patients with metastasis, the complexity and heterogeneity of diffuse diseases make prognosis prediction and systematic treatment difficult and ineffective. Therefore, we established a novel personalized immune-related gene pairs index (IRGPI) to predict the prognosis of patients with metastatic melanoma, which was conducive to provide new insights into clinical decision-making and prognostic monitoring for metastatic melanoma. Through complex analysis and filtering, we identified 24 immune-related gene pairs to build the model and obtained the optimal cut-off value from receiver operating characteristic curves, which divided the patients into high and low immune-risk groups. Meantime, the Kaplan-Meier analysis, Cox regression analysis and subgroup analysis showed that IRGPI had excellent prognostic value. Furthermore, IRGPI was shown that was closely associated with immune system in the subsequent tumor microenvironment analysis and gene set enrichment analysis. In addition, we broken through the data processing limitations of traditional researches in different platforms through the application of gene pairs, which would provide great credibility for our model. We believe that our research would provide a new perspective for clinical decision-making and prognostic monitoring in metastatic melanoma.

How to Accomplish a Square C(N)4 Substructure of the Planar Tetracoordinate Carbon.

Nitrogen-based groups are usually not used as ligands to coordinate to the ptC atom. However, here we reported only nitrogen-based ligands to accomplish a theoretically successful square planar C(N)4 substructure. The first difficulty in accomplishing a square ptC(N)4 substructure is to conquer the tremendous strain from the planar to tetrahedral arrangements, and the second is to restrict it in a suitable system with the right symmetry. We designed several neutral molecules with the square ptC(N)4 substructures, and the molecules were studied using the density functional theory method at the B3LYP/6-311++G(3df,3pd) and TPSSh/6-311++G(3df,3pd) level of theory. The results of this work show that the molecules are all real minima on the potential energy surface and successfully achieved the square ptC(N)4 substructure in the theoretical method. The group orbitals among the square ptC(N)4 arrangement in the D 2d symmetry have been discussed and used to investigate the bonding interactions among all atoms in the square ptC(N)4 substructure. Usually, the ptC systems have 18 valence electrons, but the present ptC systems mentioned in this work have 24 valence electrons, which is unusual for ptC.

Theoretical Study on Neutral Molecules with Square Planar Tetracoordinate Oxygen O(B)4 Arrangements.

As we know, oxygen usually forms two single bonds with other atoms, whereas in this work, we reported the neutral molecules with square planar O(B)4-type tetracoordinate oxygen substructures. The difficulty to achieve a square planar O(B)4-type arrangement is not only to overcome the strain from the planar to tetrahedral configuration but also to constrain it in a right system with the proper symmetry. Several neutral molecules with square planar O(B)4-type arrangements have been studied using the DFT method at the B3LYP/6-311++G(3df,3pd) level of theory. The computational results show that they are all real minima on potential energy hypersurfaces. Thus, it has been shown theoretically that the square planar O(B)4-type arrangement is achieved. The molecular orbitals among the square planar O(B)4-type substructure at D 2d symmetry have been suggested. Using the molecular orbitals, it has been explained that the oxygen 2p z -π electrons in the square planar O(B)4-type arrangement are no longer the lone-pair electrons.

(C=C=C=C)@C60: A Bonding C60-Endohedral Molecular Allotrope of Carbon.

The allotropes of carbon have been the focus of attention in recent years. In this work, we reported a molecular allotrope of carbon, C60-endohedral: (C=C=C=C)@C60. The smallest vibrational frequency is 226.0 cm-1, which confirms that (C=C=C=C)@C60 is a minimum on the potential energy hypersurface. Its geometry, NMR diagram, IR spectrum, heat of formation, and bonding interactions have been predicted using the density functional theory (DFT) method at the B3LYP/6-311G(d) level of theory. Since there must be a large family of the fullerene-endohedral allotropes of carbon, the research studies on these allotropes of carbon will open an avenue for allotropes of carbon.