Insights into N-Coordinated Bimetallic Site Synergy during NO Selective Catalytic Reduction by CO.

The nature of the synergistic effect in bimetallic catalysts remains a challenging issue, due to the difficulty in understanding the adjacent interaction between dual metals at the atomic level. Herein, a CuFe-N/C catalyst featuring diatomic metal-nitrogen sites was prepared through a sequential ion exchange strategy and applied for NO selective catalytic reduction by CO (CO-SCR). The bimetallic CuFe-N/C catalyst exhibits high N2 selectivity with a NO conversion efficiency of nearly 100% over a wide temperature range from 225 to 400 °C, significantly higher than that of its single-component counterparts. The synergistic effect of bimetallic Cu-Fe sites is well revealed using the combined in situ FTIR technique and DFT calculations. Bifunctional Cu-Fe sites are demonstrated not only to provide two different preferential adsorption centers for the CO molecule and ONNO intermediate but also to achieve a complete electron cycle for efficient interfacial electron transfer upon ONNO uptake. The unique electron transfer mechanism stemmed from 4s-3d-type electron coupling, and different 3d shell fillings of Cu (3d10) and Fe (3d6) atoms are presented. These fundamental insights pave the way for the understanding of N-coordinated bimetallic site synergy and rational design of highly active atomic-scale metal catalysts for SCR applications.

[Prognostic factors of stage IB and IIA carcinoma of the cervix treated by surgery].

OBJECTIVE: To evaluate prognostic factors in patients with stage IB-IIA of cervical carcinoma treated by surgery. METHODS: Between December 1992 and December 2001, 111 patients with stage IB-IIA cervical cancer surgically treated were analyzed. Median age 40 years. According to 1994 FIGO Staging System: IB 80 (IB1 40, IB2 40) and IIA 31. There were 93 cases of squamous cell carcinoma (83.5%), 17 cases of adenocarcinoma (15.3%) and one case of small cell carcinoma. All patients were treated by radical hysterectomy and pelvic lymphadenectomy, 74 patients had preoperative adjuvant radiotherapy, 24 patients had postoperative adjuvant treatment. Kaplan-Meier method was used to evaluate the survival, the related prognostic factors were assessed by Cox regression and chi(2) test. RESULTS: The overall 5-year survival rate was 85.9%, being 89.1%, 90.7% and 78.4% for stage IB1, IB2 and IIA, respectively. Univariate analysis showed that tumor size (hazards ratio [HR] = 1.479, P = 0.152), tumor type (HR = 1.440, P = 0.264), clinical stage (HR = 1.380, P = 0.354), adjuvant treatment (HR = 1.210, P = 0.450), lymph node metastasis (HR = 1.432, P = 0.540), endocervical involvement (HR = 2.244, P = 0.036), depth of myometrial invasion (HR = 3.295, P = 0.06) and multiple sexual partners during pregnancy (HR = 10.172, P = 0.000) were of prognostic significance. The latter two were the most important factors indicative of poor prognosis. CONCLUSION: The depth of myometrial invasion and multi-partners combined with pregnancy are closely related to the prognosis while the pre- and/or postoperative adjuvant therapy should be considered for stage IB-IIA cervical cancer with deep myometrial invasion and in pregnant patients with multiple sexual partners.

Telomerase activity in cervical intraepithelial neoplasia.

BACKGROUND: It was reported that telomerase expression is closely associated with cellular immortality and cancer. This study was designed to investigate the relationship between telomerase expression and the carcinogenesis of cervical cancer, the possible use of telomerase as a marker of cervical intraepithelial neoplasia (CIN) progression or regression, and the natural history of CIN. METHODS: Telomeric repeat amplification protocol (TRAP) assay was used to measure telomerase activity in cervical scrapings and biopsy samples obtained from 105 cases affected with various cervical conditions, including chronic cervicitis (n = 20), CIN (n = 64, 16 cases of CIN I, 20 cases of CIN II, and 28 cases of CIN III), and invasive squamous cell carcinoma (n = 21). RESULTS: In exfoliated cell samples, telomerase activity was detected in 5 of 20 (25.0%) cases of cervicitis, 10 of 16 (62.5%) cases of CIN I, 11 of 20 (55.0%) cases of CIN II, 23 of 28 (82.1%) cases of CIN III, and 13 of 21 (61.9%) cases of carcinoma. In cervical biopsy samples, telomerase activity was detected in 6 of 20 (30.0%) cases of cervicitis, 8 of 16 (50.0%) cases of CIN I, 9 of 20 (45.0%) cases of CIN II, 27 of 28 (96.4%) cases of CIN III, and 20 of 21 (95.2%) cases of carcinoma. Telomerase activation was significantly higher in CIN samples than in cervicitis samples. Telomerase activity was detected at similar frequency in samples from cervical scrapings and cervical biopsies. CONCLUSION: These results seem to suggest that telomerase expression may be associated with carcinogenesis of the cervix. TRAP assay of cervical scraping samples could be used to monitor and predict the development of CIN in clinical practice.

[Present status of radiotherapy in the treatment of gynecological malignancy].

This paper introduces radiation in the treatment of gynecological malignancy, including its importance, methods, curative effects, and some critical issues nowadays.