Catalytic hydrogenation of olefins by a multifunctional molybdenum-sulfur complex.

Exploration of molybdenum complexes as homogeneous hydrogenation catalysts has garnered significant attention, but hydrogenation of unactivated olefins under mild conditions are scarce. Here, we report the synthesis of a molybdenum complex, [Cp*Mo(Ph2PC6H4S-CH = CH2)(Py)]+ (2), which exhibits intriguing reactivity toward C2H2 and H2 under ambient pressure. This vinylthioether complex showcases efficient catalytic activity in the hydrogenation of various aromatic and aliphatic alkenes, demonstrating a broad substrate scope without the need for any additives. The catalytic pathway involves an uncommon oxidative addition of H2 to the cationic Mo(II) center, resulting in a Mo(IV) dihydride intermediate. Moreover, complex 2 also shows catalytic activity toward C2H2, leading to the production of polyacetylene and the extension of the vinylthioether ligand into a pendant triene chain.

Clinical risk stratification of acute pulmonary embolism: comparing the usefulness of CTA obstruction score and pulmonary perfusion defect score with dual-energy CT.

To compare the ability of CT angiography (CTA) obstruction score and perfusion defect score on dual energy CT perfusion imaging (DEPI) for clinical risk stratification of patients with acute pulmonary embolism (PE). 55 patients diagnosed as acute PE either by CTA or DEPI were retrospectively enrolled. Patients were grouped into high-, intermediate-, and low-risk groups in accordance to the renewed guidelines of 2014. Consistency between DEPI and CTA in diagnosis of PE were assessed. Correlations between CT parameters and right-to-left ventricular (RV/LV) diameter ratio were evaluated. Difference of CTA obstruction score and perfusion defect score across three groups with different risks were analyzed. The consistent rate of DEPI with CTA was 75.4%, and the Kappa value was 0.412 (p = 0.000). 44.3% of partially obstructive PE showed on CTA did not lead to perfusion defect on DEPI. Perfusion defect score was significantly correlated with CTA obstruction score and with RV/LV (r = 0.622 and 0.599, respectively, p < 0.001), and CTA obstruction score had lower correlation with RV/LV (r = 0.403, p = 0.003). Perfusion defect score could distinguish low- from intermediate-risk groups (p = 0.011). However, CTA obstruction score could not distinguish the two groups (p = 0.149). DEPI had fine consistency with CTA to diagnose acute PE and offered additional information of physiologic changes. Comparing with CTA obstruction score, perfusion defect score could better correlate with right ventricular dysfunction, and could be a more promising biomarker for clinical risk stratification.

[Clinical value of dual-source CT angiography in the diagnosis of postoperative aortic intramural hematoma in patients with endovascular stent-graft exclusion surgery].

OBJECTIVE: To determine the clinical value of dual-source CT angiography (DSCTA) in the diagnosis of postoperative aortic intramural hematoma (AIMH) in patients with endovascular stent-graft exclusion (EVE) surgery. METHODS: Between Oct 2008 and May 2013, thirty-six patients were diagnosed with AIMH by DSCTA, and 12 of these patients with type B underwent EVE. The 12 patients were followed up with DSCTA, which included imaging reconstruction (multi-plane reconstruction, MPR), maximum intensity projection (MIP) and volume rendering technique (VRT). The extent and type of AIMH, aortic ulcers and the outcomes and complications of AIMH were observed. RESULTS: The 36 cases of AIMH included 11 Stanford type A and 25 type B. No tearing intimal flap or contrast materials within the hematoma were observed. The maximum aortic diameter of the hematoma areas varied from 3.8 to 5.4 cm (average 4.3 cm) and the maximum thickness of the hematoma ranged from 0.5 cm to 1.3 cm (average 0.9 cm). The ratio between the minimum and the maximum diameter of the aortic lumen in the hematoma areas ranged from 0. 74 to 0. 98 (average 0.85). Aortic ulcers were revealed in 3 patients with type A AIMH and 8 patients with type B AIMH. Intimal tearing of distal abdominal aorta was found in 3 patients with type B AIMH. In the 12 patients underwent EVE surgery, hematoma shrank in all cases with 4 cases almost resolving and aortic ulcers in the area of stent-graft exclusion disappeared in 3 cases. The form of stent-graft appeared normal in 9 cases and slightly abnormal in 3 cases. Fluent main branches of aortic arch and none existence of stent endoleaking were observed. CONCLUSION: DSCTA with handy, effective and non-invasive advantages is one of the important imaging methods in the diagnosis of AIMH in patients with EVE surgery.