ABSTRACT
The atomic precision of sub-nanometer-sized metal nanoclusters makes it possible to elucidate the kinetics of metal nanomaterials from the molecular level. Herein, the size reduction of an atomically precise [Au23(CHT)16]- (HCHT = cyclohexanethiol) cluster upon ligand exchange with HSAdm (1-adamantanethiol) has been reported. During the 16 h conversion of [Au23(CHT)16]- to Au16(SR)12, the neutral 6e Au21(SR)15, and its 1e-reduction state, i.e. the 5e, cationic radical, [Au21(SR)15]+, are active intermediates to account for the formation of thermodynamically stable Au16 products. The combination of spectroscopic monitoring (with UV-vis and ESI-MS) and DFT calculations indicates the preferential size-reduction on the corner Au atoms on the core surface and the terminal Au atoms on longer AunSn+1 staples. This study provides a reassessment on the electronic state of the Au21 structure and highlights the single electron transfer processes in cluster systems and thus the importance of the EPR analysis on the mechanistic issues.
ABSTRACT
The recent progress in atomically precise metal (Au, Ag etc.) nanoclusters has greatly enriched the molecular-level mechanistic understanding of metal nanomaterials. Herein, using two meta-stable (easy formation, easy transformation) clusters, i.e. [Au23SCy16]- and [Au6(dppp)4]2+ (HSCy and dppp denote cyclohexanethiol and 1,3-bis(diphenylphosphino)propane), as the reaction precursors, the etching of Au23 occurs smoothly, giving the one/two-atom size-reduced [Au21SCy12(dppp)2]+ and [Au22SCy14(dppp)]2+ as the major products. Structural analysis and DFT calculations indicate that the active reaction site of Au23 lies in the core-shell interference of the bi-capped icosahedral Au15 core and the AuS2 motifs. The fluorescence, band gap, and thermostability of the Au21 cluster products are improved compared to that of the Au23 precursors.
ABSTRACT
BACKGROUND: To establish and validate a nomogram to predict liver metastasis in patients with small-cell lung cancer (SCLC). METHODS: Information on patients diagnosed with SCLC between 2010 and 2015 was retrospectively retrieved from the Surveillance, Epidemiology, and End Results (SEER) database. Risk factors for liver metastasis were identified by logistic regression analyses to construct a nomogram. The predictive accuracy was evaluated by concordance indexes (c-index) and calibration plots, and the comparison of discrimination between the nomogram and other routine staging systems was achieved with the area under receiver operating characteristic curve (AUC) analysis. Decision curve analysis (DCA) was performed to measure the clinical performance of the nomogram. RESULTS: A total of 12,957 patients met our inclusion criteria and were randomly assigned to training (n=6,479) and validation (n=6,478) sets. The nomogram which was established based on independent clinicopathological factors had poor accuracy, and after other distant metastatic sites were added into the predictive model, the new nomogram displayed better discrimination power, with c-indexes of 0.703 in the training set and 0.712 in the validation set. Both internal and external calibration plots approached 45 degrees. The AUCs and net benefit of the predictive model were both higher than those of routine staging systems. CONCLUSIONS: The validated nomogram might be a practical tool for clinicians to quantify the risk of liver metastasis in patients with SCLC and improve cancer management.
Subject(s)
Liver Neoplasms , Lung Neoplasms , Humans , Nomograms , Retrospective Studies , SEER ProgramABSTRACT
Removal of a triphenylmethane dye (crystal violet, CV) by a simultaneous enzymatic-photocatalytic-adsorption treatment was investigated in this work. A desirable synergistic effect on dye treatment was achieved by decorating laccase (Lac) onto the surface of TiO2 sol-gel coated polyacrylonitrile/organically modified montmorillonite (PAN/O-MMT) nanofibers prepared by electrospinning. The assembly of Lac on the surface of PAN/O-MMT/TiO2 nanofibers was confirmed by confocal laser scanning microscope (CLSM). In comparison with free Lac, the immobilized Lac showed better pH, temperature and operational stabilities, reaching highest relative activity at an optimum pH of 3 and optimum temperature of 50 °C. Therefore, the immobilized Lac displayed a higher degradation efficiency of CV at an initial dye concentration of 100 mg/L, an optimum pH of 4.5 and temperature at 60 °C. Under UV illumination, the CV removal efficiency was further improved by ~20%. These results demonstrated that the Lac-immobilized PAN/O-MMT/TiO2 composite nanofibers with a combined effect between the immobilized enzyme and the polymeric support have potential for industrial dye degradation.
ABSTRACT
BACKGROUND: Gastric cancer (GC) is one of the leading causes of cancer-related death worldwide. This study was designed to investigate the prognostic values of red blood cell (RBC)-associated indicators, including RBC, hemoglobin (HGB), hematocrit (HCT), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), and RBC distribution width (RDW) in resectable GC patients. METHODS: In this retrospective study, a total of 104 pathologically confirmed GC patients were recruited. These cases were divided into two groups according to the median values of pretreatment RBC, HGB, HCT, MCV, MCH, MCHC, or RDW. To evaluate the changes in RBC-associated indicators values after treatment, we introduced the concept of post-/pre-treatment ratios (≤1 suggested RBC, HGB, HCT, MCV, MCH, MCHC, or RDW values were not increased after therapy, while >1 represented those in increased levels). RESULTS: The lower pretreatment MCHC levels were correlated with worse overall survival (OS), while pretreatment levels of RBC, HGB, HCT, MCV, MCH, or RDW were not. The whole course of treatment (surgery plus adjuvant chemotherapy) significantly decreased the values of MCHC, and increased the values of MCV and RDW, whereas it had no obvious effects on the values of RBC, HGB, HCT, or MCH. Patients with post-/pre-treatment MCV ratio >1 had an increased survival ratio. Meanwhile, post-/pre-treatment RBC, HGB, HCT, MCH, MCHC, or RDW ratios were not correlated with outcomes. Multivariate Cox regression analysis revealed that the American Joint Committee on Cancer (AJCC) stage (III), and lower pretreatment MCHC levels were independent risk factors affecting OS. The receiver operating characteristic (ROC) curve analysis showed that an MCHC value of 341.98 g/L was the optimal cutoff value for prognosis, with a sensitivity of 58.3% and a specificity of 75.0%. CONCLUSIONS: Pretreatment MCHC levels could become a potential prognostic factor for resectable GC.
ABSTRACT
BACKGROUND: Breast cancer is the leading cause of cancer death in the female population. Platelet-related indicators can be used as prognostic markers of cancers. The present study investigated the potential values of platelet count (PLT), plateletcrit (PCT), mean platelet volume (MPV), platelet distribution width (PDW), and platelet to lymphocyte ratio (PLR) in the prognosis of advanced breast cancer (ABC). METHODS: This retrospective study recruited 94 locally advanced or metastatic breast cancer cases who had histologic and cytologic evidence. The patients were divided into two groups according to the median baseline values of PLT, PCT, MPV, PDW, and PLR. To evaluate the individual value changes after treatment, we introduced the concept of post/pre-treatment ratio (≤1 indicated value was not increased after treatment, while >1 suggested increased value). Responses to chemotherapy, including partial response (PR), stable disease (SD), and progressive disease (PD), were recorded. Kaplan-Meier curves were constructed to show overall survival (OS). Univariate and multivariate Cox regression analysis models were employed to identify the independent risk factors. RESULTS: A lower baseline PCT level was correlated with a better OS. A lower baseline PLT level and a higher baseline PDW level were related to better chemotherapeutic efficacy of breast cancer patients. Univariate analysis and multivariate analysis both revealed that a higher baseline PCT level was an independent prognostic factor for OS. CONCLUSIONS: PCT level may be a potential prognosis factor for ABC.
