Charge Density Modulation of Pyrene-Related Small Molecules by Nitrogen Heteroatoms Precisely Regulates Photocatalytic Generation of Hydrogen.

Organic semiconductor materials hold promising applications in photocatalytic hydrogen evolution due to their high modifiability and wide range of light absorption capability. In this study, we present an effective strategy for promoting the separation of photoexcited electrons from organic conjugated centers to active sites by modifying different nitrogen-containing groups on pyrene molecules. Building on this foundation, the well-designed catalyst Py-m-2N has demonstrated good performance by achieving a photocatalytic hydrogen evolution rate of 48.86 mmol g-1 h-1, even in the absence of the precious metal platinum cocatalyst. This achievement places the pyrene-based photocatalyst ahead of the majority of its organic counterparts. Our comprehensive characterization and density functional theory calculations reveal that the nitrogen atom not only serves as an active site for hydrogen production but also plays a pivotal role in efficiently accumulating bulk-phase electrons. This electron enrichment process enhances the transport of photoexcited electrons from the light-absorbing pyrene units to the active nitrogen sites. This work provides inspiration for the future design of effective nitrogen-atom-modified organic semiconductor photocatalysts at the molecular level.

Immobilization CoOOH nanosheets on biochar for peroxymonosulfate activation: Built-in electric field mediated radical and non-radical pathways.

The strong electron interaction between metal oxide-carbon-based catalyst components plays a vital role in the peroxymonosulfate (PMS) activation for pollutant degradation. Herein, a novel CoOOH nanosheets anchored on rape straw-derived biochar (BC) surface (labeled as CoOOH/BC) as an efficient PMS activator toward degrading sulfamethoxazole (SMX) was synthesized. Experimental results indicated that integrating CoOOH nanosheets on the BC surface could inhibit CoOOH aggregation to increase the specific surface areas, exert a component synergistic effect to enhance activation degradation activity, and improve the catalyst stability. As a result, a 96 % degradation efficiency of SMX was achieved within 20 min over 20 wt% CoOOH/BC composite catalyst under the optimal conditions. Density functional theory (DFT) calculations disclosed that a built-in electric field (BIEF) pointing from BC to CoOOH was constructed at their interface, which could mediate PMS activation for reactive oxygen species (ROS) generation and induce direct electron transfer from SMX to PMS, resulting in efficient SMX degradation via both radical and non-radical pathways. Moreover, quenching experiments and electron paramagnetic resonance (EPR) measurements confirmed that single oxide (1O2) and superoxide radical (O2·-) are the dominant active species in the current system. Additionally, the possible SMX degradation routes were reasonably proposed based on liquid chromatography-mass spectrometry (LC-MS) results. This work provides an in-depth understanding of the role of BIEF in PMS activation, and expands the application of biochar-based materials in the field of environmental remediation.

3-(1,3-Dioxoisoindolin-2-yl)propane-nitrile.

In the title compound, C(11)H(8)N(2)O(2), the packing is consolidated by C-H⋯N and C-H⋯O inter-actions.

[Comparison by dynamic enhancement in spiral CT to differentiate peripheral squamous cell carcinoma from adenocarcinoma of the lung].

OBJECTIVE: To compare the manifestations of peripheral lung squamous cell carcinoma by CT dynamic enhancement with that of adenocarcinoma, and evaluate the difference of CT dynamic enhancement to distinguish peripheral lung squamous cell carcinomas from adenocarcinoma. METHODS: Thirty peripheral lung squamous cell carcinomas and 40 adenocarcinomas were examined with dynamic contrasted CT, enhancement at various phases recorded, based on which the time-intensity curves were produced. The enhancement patterns were compared and analyzed. RESULTS: There was no statistically significant difference in the enhancement degree and peak time between peripheral lung squamous cell carcinoma and adenocarcinoma (P > 0.05). The difference in enhancement pattern between these two different types of carcinoma was not statistically significant when the lesion was larger than 3 cm in diameter (P > 0.05), whereas it became statistically significant when the lesion is less than 3 cm (P < 0.05). Most of the squamous cell carcinoma showed heterogeneous enhancement or peripheral enhancement in the tumor zone, however, most of the adenocarcinomas had homogenous enhancement. CONCLUSION: The maximum enhancement and the peak time are not helpful in differentiating peripheral lung squamous cell carcinoma from adenocarcinoma. When the lesion is less than 3 cm in diameter, the enhancement pattern of peripheral squamous cell carcinomas is different from that of adenocarcinoma.

Bladder tumors: dynamic contrast-enhanced axial imaging, multiplanar reformation, three-dimensional reconstruction and virtual cystoscopy using helical CT.

BACKGROUND: There have been few studies to evaluate the effects of helical CT on bladder tumor. This study was to evaluate the clinical applications of helical CT dynamic contrast-enhanced axial imaging, multiplanar reformation (MPR), three-dimensional (3D) reconstruction and virtual cystoscopy (CTVC) in bladder tumors. METHODS: The precontrast and four-phase postcontrast helical CT scans were performed in 42 patients with bladder tumors confirmed by conventional cystoscopy and pathology. MPR, 3D and CTVC images were generated from the volumetric data of the excretory phase. The results were then compared with the findings of conventional cystoscopy and surgery in a double-blinded mode. RESULTS: The sensitivity of the axial, 3D and CTVC images in detecting the bladder tumors were 90.8%, 76.9% and 95.4% respectively. The dynamic contrast-enhanced axial images could provide excellent intramural and extravesical information, and the accuracy in preoperative tumor staging was 87.7%. MPR could directly demonstrate the origin and extravesical invasions of the tumors and their relation to the ureter. 3D and CTVC images were useful for displaying the surface morphology of the tumor and the relationship between the tumor and the ureteric orifices, whereas CTVC could depict the tumors smaller than 5 mm that were not seen on the axial images. CONCLUSIONS: The combination of axial, MPR, 3D and CTVC images with helical CT can provide comprehensive information on bladder tumor.

[Value of helical CT in bladder tumor].

OBJECTIVE: To evaluate the diagnostic effect of helical CT on bladder tumor. METHODS: In 28 patients with bladder tumors which had been confirmed by conventional fiberoptic cystoscopy (FC) and pathology, precontrast and four-phase postcontrast helical CT scans were performed with multiple plane reconstruction (MPR), three dimensional (3D) reconstruction and CT virtual cystoscopy (CTVC) images constructed from the volumetric data of the excretory phase. The results were then compared with the findings of conventional fiberoptic cystoscopy and surgery through a double-blind manner. RESULTS: The sensitivity of the helical CT axial, 3D and CTVC images in detecting bladder tumor were 92.3%, 76.9% and 96.2% respectively. The accuracy in preoperative tumor staging of helical CT was 83.0%. The axial images could provide excellent intramural and extravesical information, and MPR could directly show the origin and extravesical invasion of the tumor and its relation to the ureter. 3D and CTVC images were useful in displaying the surface morphology of the tumor and its relation with the ureteric orifices, whereas CTVC images could depict a tumor smaller than 5 mm that could not be visualized on the axial images. CONCLUSION: Combining interpretation of axial, MPR, 3D and CTVC images, helical CT is able to provide comprehensive information for the diagnosis and treatment of bladder tumor.