In Situ Surfaced Mn-Mn Dimeric Sites Dictate CO Hydrogenation Activity and C2 Selectivity over MnRh Binary Catalysts.

Massive ethanol production has long been a dream of human society. Despite extensive research in past decades, only a few systems have the potential of industrialization: specifically, Mn-promoted Rh (MnRh) binary heterogeneous catalysts were shown to achieve up to 60% C2 oxygenates selectivity in converting syngas (CO/H2) to ethanol. However, the active site of the binary system has remained poorly characterized. Here, large-scale machine-learning global optimization is utilized to identify the most stable Mn phases on Rh metal surfaces under reaction conditions by exploring millions of likely structures. We demonstrate that Mn prefers the subsurface sites of Rh metal surfaces and is able to emerge onto the surface forming MnRh surface alloy once the oxidative O/OH adsorbates are present. Our machine-learning-based transition state exploration further helps to resolve automatedly the whole reaction network, including 74 elementary reactions on various MnRh surface sites, and reveals that the Mn-Mn dimeric site at the monatomic step edge is the true active site for C2 oxygenate formation. The turnover frequency of the C2 product on the Mn-Mn dimeric site at MnRh steps is at least 107 higher than that on pure Rh steps from our microkinetic simulations, with the selectivity to the C2 product being 52% at 523 K. Our results demonstrate the key catalytic role of Mn-Mn dimeric sites in allowing C-O bond cleavage and facilitating the hydrogenation of O-terminating C2 intermediates, and rule out Rh metal by itself as the active site for CO hydrogenation to C2 oxygenates.

Electrochemical hydrogen evolution on Pt-based catalysts from a theoretical perspective.

Hydrogen evolution reaction (HER) by splitting water is a key technology toward a clean energy society, where Pt-based catalysts were long known to have the highest activity under acidic electrochemical conditions but suffer from high cost and poor stability. Here, we overview the current status of Pt-catalyzed HER from a theoretical perspective, focusing on the methodology development of electrochemistry simulation, catalytic mechanism, and catalyst stability. Recent developments in theoretical methods for studying electrochemistry are introduced, elaborating on how they describe solid-liquid interface reactions under electrochemical potentials. The HER mechanism, the reaction kinetics, and the reaction sites on Pt are then summarized, which provides an atomic-level picture of Pt catalyst surface dynamics under reaction conditions. Finally, state-of-the-art experimental solutions to improve catalyst stability are also introduced, which illustrates the significance of fundamental understandings in the new catalyst design.

Human bocavirus 1 is a genuine pathogen for acute respiratory tract infection in pediatric patients determined by nucleic acid, antigen, and serology tests.

Background: Human bocavirus 1 (HBoV1), first discovered in 2005, was positive in symptomatic and healthy children and co-detected with other respiratory viruses. It is a long journey to decisively demonstrate the unique viral pathogenic function of acute respiratory tract infection (ARTI) in pediatric patients. Methods: Respiratory specimens collected from pediatric patients with ARTI from January 2017 to December 2021 were screened by a capillary electrophoresis-based multiplex PCR (CEMP) assay, then genotyped by PCR and sequencing for HBoV1. For the antigen test, a part of HBoV1 DNA positive nasopharyngeal aspirates (NPAs) was used as an antigen, while a rabbit anti-HBoV1 DR2 specific to HBoV1 was used as an antibody in the indirect-immunofluorescence assay (IFA). Finally, the levels of IgG specific to HBoV1 in acute and convalescent sera selected retrospectively from only HBoV1 DNA-positive patients were evaluated by IFA. Results: Among 9,899 specimens, 681 were positive for HBoV1 DNA (6.88%, 681/9899), which included 336 positives only for HBoV1 (49.34%, 336/681) and 345 (50.66%, 345/681) positives also for other pathogens. In the antigen test, there were 37 among 47 NPAs determined as HBoV1 antigen-positive (78.72%, 37/47), including 18 (48.65%, 18/37) positives solely for HBoV1 DNA. Among 4 pediatric patients with both acute and convalescent sera, there was one positive for HBoV1 antigen (D8873) and 2 lack the antigen results (D1474 and D10792), which showed seroconversion with a ≥ 4-fold increase in IgG levels. Conclusions: The combination results of nucleic acid, antigen, and serology tests answered that HBoV1 is a genuine pathogen for ARTI in pediatric patients.

Stability and anion diffusion kinetics of Yttria-stabilized zirconia resolved from machine learning global potential energy surface exploration.

Yttria-stabilized zirconia (YSZ) is an important material with wide industrial applications particularly for its good conductivity in oxygen anion transportation. The conductivity is known to be sensitive to Y concentration: 8 mol. % YSZ (8YSZ) achieves the best performance, which, however, degrades remarkably under ∼1000 °C working conditions. Here, using the recently developed SSW-NN method, stochastic surface walking global optimization based on global neural network potential (G-NN), we establish the first ternary Y-Zr-O G-NN potential by fitting 28 803 first principles dataset screened from more than 107 global potential energy surface (PES) data and explore exhaustively the global PES of YSZ at different Y concentrations. Rich information on the thermodynamics and the anion diffusion kinetics of YSZ is, thus, gleaned, which helps resolve the long-standing puzzles on the stability and conductivity of the 8YSZ. We demonstrate that (i) 8YSZ is the cubic phase YSZ with the lowest possible Y concentrations. It is thermodynamically unstable, tending to segregate into the monoclinic phase of 6.7YSZ and the cubic phase of 20YSZ. (ii) The O anion diffusion in YSZ is mediated by O vacancy sites and moves along the ⟨100⟩ direction. In 8YSZ and 10YSZ, despite different Y concentrations, their anion diffusion barriers are similar, ∼ 1 eV, but in 8YSZ, the O diffusion distance is much longer due to the lack of O vacancy aggregation along the ⟨112⟩ direction. Our results illustrate the power of G-NN potential in solving challenging problems in material science, especially those requiring a deep knowledge on the complex PES.

Hydrogen-rich saline injection into the subarachnoid cavity within 2 weeks promotes recovery after acute spinal cord injury.

Hydrogen can relieve tissue-damaging oxidative stress, inflammation and apoptosis. Injection of hydrogen-rich saline is an effective method for transporting molecular hydrogen. We hypothesized that hydrogen-rich saline would promote the repair of spinal cord injury induced by Allen's method in rats. At 0.5, 1, 2, 4, 8, 12 and 24 hours after injury, then once daily for 2 weeks, 0.25 mL/kg hydrogen-rich saline was infused into the subarachnoid space through a catheter. Results at 24 hours, 48 hours, 1 week and 2 weeks after injury showed that hydrogen-rich saline markedly reduced cell death, inflammatory cell infiltration, serum malondialdehyde content, and caspase-3 immunoreactivity, elevated serum superoxide dismutase activity and calcitonin gene-related peptide immunoreactivity, and improved motor function in the hindlimb. The present study confirms that hydrogen-rich saline injected within 2 weeks of injury effectively contributes to the repair of spinal cord injury in the acute stage.

[Feasibility of endoscopic surgery by paravertebral approach in far lateral lumbar disc herniation].

OBJECTIVE: To evaluate the feasibility of endoscopic paravertebral approach surgery in the far lateral lumbar disc herniation. METHODS: Fifty sets of integral lumbar vertebral specimens were selected, and the anatomical data of lumbar intervertebral foramina and its adjacent structures were measured. Twenty specimens are randomly divided into a traditional group and an endoscopic group, then the traditional and endoscopic operations by paravertebral approach were used to dissect every strata of soft tissues in order to expose the intervertebral foramen. At last,the relationship between the intervertebral foramen and its adjacent structures was observed, and the 2 procedures were compared. RESULTS: The sagittal diameter of lumbar intervertebral foramina became shorter from the top to bottom,while the diameter of cross section of relative nerve roots became longer. The depth of the line which connected the middle point of the 2 adjacent transverse process roots and the anterior branch of lumber nerve root in L1,L3 and L5 was (1.03+/-0.30), (1.71+/-0.29), and (1.99+/-0.34) mm respectively, with the increasing tendency; the depth of L3 to L5 was mostly less than 2 cm. The distance of the middle points of the 2 adjacent transverse process roots from L1 to L5 was long enough, but the distance between L5 and S1 was only (10.14+/-1.71) mm. The surgery by paravertebral approach had a relative safe operation area,which was similar to a triangle. CONCLUSION: The technique of endoscopic surgery by paravertebral approach is feasible in the treatment of far lateral lumbar disc herniation. However, it is difficult to perform this surgery in the treatment of L5/S1 far lateral lumbar disc herniation, which is often conducted with endoscopy, after 18 to approximately 20 mm of the partial sacrum is eliminated by conventional method.

[Mentality and behavior of children suffering from viral myocarditis].

OBJECTIVE: The present study was designed to investigate the influence of viral myocarditis on mental behavior of the children. METHODS: Mentality and behavior of the 178 children suffering from viral myocarditis were examined with Achenbach Child Behavior Checklist (CBCL) edited by Gong Yao-xian in 1986 and 104 sex, age, education and achievement-matched children with pneumonia or upper respiratory infection were enrolled as controls. RESULTS: The mentality and behavior of the children with viral myocarditis were distinctly abnormal. The abnormal rates of boys and girls suffering from acute and deferment viral myocarditis were evidently higher than those of control children (P < 0.01). The behavioral abnormalities of boys were hypochondria, social difficulties, unwell of body and attack. Whereas, the girls presented hypochondria, unwell of body, social flinch and disobeyed discipline, which was significantly different from the control children. The total and hypochondria cursory mark of the second check result of deferment boys were evidently higher than those of the first check (P < 0.05). The total cursory mark of the second check result of deferment girls was higher than that of the first check (P < 0.05) and evidently higher than that of the acute second check result (P < 0.01). The abnormal rates of mentality and behavior correlated positively with the age of children and they were associated with the severity of the illness. CONCLUSION: Viral myocarditis evidently affected the mentality and behavior of children, which should be paid great attention to.