Clinical applications of retrograde autologous priming in cardiopulmonary bypass in pediatric cardiac surgery

Retrograde autologous priming (RAP) has been routinely applied in cardiac pediatric cardiopulmonary bypass (CPB). However, this technique is performed in pediatric patients weighing more than 20 kg, and research about its application in pediatric patients weighing less than 20 kg is still scarce. This study explored the clinical application of RAP in CPB in pediatric patients undergoing cardiac surgery. Sixty pediatric patients scheduled for cardiac surgery were randomly divided into control and experimental groups. The experimental group was treated with CPB using RAP, while the control group was treated with conventional CPB (priming with suspended red blood cells, plasma and albumin). The hematocrit (Hct) and lactate (Lac) levels at different perioperative time-points, mechanical ventilation time, hospitalization duration, and intraoperative and postoperative blood usage were recorded. Results showed that Hct levels at 15 min after CPB beginning (T2) and at CPB end (T3), and number of intraoperative blood transfusions were significantly lower in the experimental group (P0.05). Postoperatively, there were no significant differences in Hct (2 h after surgery), mechanical ventilation time, intensive care unit time, or postoperative blood transfusion between two groups (P>0.05). RAP can effectively reduce the hemodilution when using less or not using any banked blood, while meeting the intraoperative perfusion conditions, and decreasing the perioperative blood transfusion volume in pediatric patients

Atomic Insights into Robust Pt-PdO Interfacial Site-Boosted Hydrogen Generation

Suppression of catalyst deactivation without compromising activity has been a long-standing yet elusive goal in heterogeneous catalysis. Herein, we report a remarkable achievement of both hydrogen generation activity and durability by atomically engineering Pt–PdO interfacial sites. A combination of kinetics (isotopic) analyses, multiple characterization techniques, molecular dynamics, and density functional theory calculations was employed to reveal the evolution of the Pt–Pd atomic structure where Pd segregates to the outer surface of Pt nanoparticles, followed by partial oxidation, resulting in the structure of a Pt-rich core and a PdO–Pd-rich shell. The strong capability of PdO to activate H2O compensates for its adverse effects on Pt electronic properties and creates the Pt and PdO interfacial sites for ammonia borane and H2O activation, respectively. Moreover, because of the strong electron repulsion and steric hindrance effects, these surface PdO sites strongly inhibit the adsorption of B(OH)4–, thus protecting Pt active sites from poisoning. As a result, such a unique atomic structure with a Pt–Pd ratio of 1:1 is found to be the most promising catalyst at the apex of the volcano curve. The strategy developed here unambiguously clarifies the activity and durability attributes of Pt–PdO interfacial sites for this reaction and sheds light on the design of a new type of highly active yet stable metal catalysts

Fine tuning of pentachromium(II) metal string complexes through elaborate design of ligand

New pentachromoium metal string complexes [Cr-5(mu(5)-L)(4)X-2] (X = Cl-, L = dppzda(2-) (1), dpzpda(2-) (2); X = NCS-, L = dppzda(2-) (3), dpzpda(2-) (4)) were designed and synthesized through pyrazine-modulation of tripyridyldiamine ligand. X-Ray crystallographic studies revealed a linear metal chain structure consisting of two quadruple Cr-Cr bonds and a separated high spin Cr(II) at an end in crystallized form. A quintet ground state was observed for all pentachromium(II) molecules by magnetic study with g values of 2.04-2.18. While the electronic structure remained unchanged after the modification of ligands, electrochemistry showed a significant change in the molecular orbital energy levels of metal string molecules. Observation of the first oxidation peak of 1 at +0.57 V and of 2 at +0.73 V revealed that these complexes are quite resistant to oxidation. Single molecular conductance measurements showed that the complex exhibited good electronic conductance

Polymer decoration of carbon support to boost Pt-catalyzed hydrogen generation activity and durability

Decorating the catalyst support with organic moieties to integrate multiple functionalities into metal particles offers a unique platform to promote the catalytic performance. Here, we report a mechanism-driven strategy to functionalize CNT with dual polymers, endowing the supported Pt catalyst with simultaneously enhanced hydrogen generation activity and durability. Kinetics analysis, multiple characterization and DFT calculations reveal that the PDDA acts as electron-acceptor to capture electrons from the Pt particles toward strengthened adsorption of reactants, while the PVP acts as structure-directing agent to induce the catalyst morphology evolution with a preferential exposure of Pt(1 1 1) active sites. Such electronic and geometric synergy by co-functionalizing PDDA and PVP gives rise to a 3-fold increase in the hydrogen generation activity, together with remarkably improved catalytic durability due to the suppressed adsorption of B(OH)4− over the Pt(1 1 1). The strategy reported here might shed new lights on establishing the functionalization protocols to design carbon supported metal catalysts with the targeted properties