Mechanocatalytic Synthesis of Ammonia by Titanium Dioxide with Bridge-Oxygen Vacancies: Investigating Mechanism from the Experimental and First-Principle Approach.

Mechanochemical ammonia (NH3 ) synthesis is an emerging mild approach derived from nitrogen (N2 ) gas and hydrogen (H) source. The gas-liquid phase mechanochemical process utilizes water (H2 O), rather than conventional hydrogen (H2 ) gas, as H sources, thus avoiding carbon dioxide (CO2 ) emission during H2 production. However, ammonia yield is relatively low to meet practical demand due to huge energy barriers of N2 activation and H2 O dissociation. Here, six transition metal oxides (TMO) such as titanium dioxide (TiO2 ), iron(III) oxide (Fe2 O3 ), copper(II) oxide (CuO), niobium(V) oxide(Nb2 O5 ), zinc oxide (ZnO), and copper(I) oxide (Cu2 O) are investigated as catalysts in mechanochemical N2 fixation. Among them, TiO2 shows the best mechanocatalytic effect and the optimum reaction rate constant is 3.6-fold higher than the TMO-free process. The theoretical calculations show that N2 molecules prefer to side-on chemisorb on the mechano-induced bridge-oxygen vacancies in the (101) crystal plane of TiO2 catalyst, while H2 O molecules can dissociate on the same sites more easily to provide free H atoms, enabling an alternative-way hydrogeneration process of activated N2 molecules to release NH3 eventually. This work highlights the cost-effective TiO2 mechanocatalyst for ammonia synthesis under mild conditions and proposes a defect-engineering-induced mechanocatalytic mechanism to promote N2 activation and H2 O dissociation.

Geometric-feature-based approach to human face reconstruction with high measurement speed.

This paper presents a method based on geometry for three-dimensional (3D) face reconstruction without the need for additional images, hardware components, or objects. In our proposed method, we consider part of the nose as the feature region because its shape remains almost constant during the measurement. The geometry of this region was used to provide cues for phase unwrapping. We first spatially unwrap the phase and determine the integer multiple of 2π to be added by comparing the recovered result of the feature region and its actual shape. Then, the face can be reconstructed with the acquired absolute phase. Experimental results demonstrated that our method is capable of reconstructing a dynamic face with high measurement speed, and only three phase-shifted fringes are required per frame.

Preventive effect and mechanism of compound Danshen dripping pills on contrast-induced nephropathy after percutaneous coronary interventional.

Background: Contrast-induced nephropathy (CIN) is one of the most common complications after coronary stent implantation due to the extensive development of coronary catheterization technology. Compound Danshen dripping pills (CDDP) are clinically used as cardiovascular drugs, relieving systemic inflammatory response. Previous studies have observed that CDDP can decrease CIN incidence after coronary stent implantation with uncertain effectiveness. Methods: We conducted a prospective, randomized, single-center, single-blind, controlled trial. We enrolled patients 18 years and older with unstable angina pectoris and NSTEMI who underwent PCI at the Tianjin Chest Hospital between November 1, 2021, and November 31, 2022, and followed for 30 days. Patients were randomized to CDDP and hydration therapy (10 capsules three times/day; N = 411) or hydration only (N = 411). The primary outcome was the contrast nephropathy incidence, defined as an elevation in serum creatinine by more than 25% or 44 µmol/L from baseline within 48-72 h of contrast exposure. Secondary outcomes included major adverse cardiovascular events post-surgery and during follow-up. Results: After 48 h of operation, the two groups had statistical significance in Scr and BUN values (80.0 ± 12.59 vs. 84.43 ± 13.49, P < 0.05; 6.22 ± 1.01 vs. 6.40 ± 0.93, P < 0.05). The difference in Scr in 72 h between the two groups was statistically significant (76.42 ± 10.92 vs. 79.06 ± 11.58, P < 0.05). The CIN incidence was significantly lower in the CDDP group than in the hydration group. The CIN risk was significantly elevated in patients with LVEF <50%, contrast volume ≥160 ml, and hypertension, after 48 and 72 h of operation. The serum inflammation index levels NGAL, TNF-α, oxidative stress indexes SOD, and MDA significantly differed between the two groups. However, there was no significant difference in serum apoptosis indexes Bax, Bcl-2, and Casepase-9. Conclusions: CDDP pre-treatment could prevent contrast-induced nephropathy. Inflammatory response and oxidative stress could be significant in the CDDP mechanism.