Partial Surface Oxidation of Manganese Oxides as an Effective Treatment To Improve Their Activity in Electrochemical Oxygen Reduction Reaction

Enhancing the electrocatalytic activity of low-cost transition-metal oxides for oxygen reduction reaction (ORR) is a crucial challenge for extensive application of fuel cells. A promising approach demonstrated previously is the formation of catalysts with mixed valent metal active sites. Because catalysis happens primarily on the surface of the catalyst, we hypothesize that creating such active sites only on the surface will be an effective strategy for improving the catalytic activities. Here, we present a partial oxidation approach that grows δ-MnO2 nanoflakes on the surface of octahedron Mn3O4 nanocrystals for increasing their ORR activity. The δ-MnO2/Mn3O4 nanocomposite exhibits significantly improved ORR activity with a half-wave potential of 0.75 V versus reversible hydrogen electrode, which is ∼110 and ∼90 mV lower than those of the Mn3O4 nanocrystal and δ-MnO2 nanoflakes in their pure forms, respectively. The electrochemical impedance spectroscopy reveals that the δ-MnO2/Mn3O4 nanocomposite possesses a lower ORR charge transfer resistance than either component alone. We propose that the reason for such significant improvement in catalytic activities is due to the tuning of the position of δ-MnO2 nanoflake d-band center by the Mn3O4 nanocrystal which can effectively facilitate the electron transfer between the active sites and adsorbed oxygen molecules. This work illustrates a facile pathway to improve catalytic activity of mixed valence metal oxides

Data_Sheet_1_The burden of cirrhosis and other chronic liver diseases due to hepatitis B in children and adolescents: results from global burden of disease study 2019.PDF

BackgroundThe global burden of cirrhosis and other chronic liver diseases due to hepatitis B (collectively referred to as hepatitis B-associated cirrhosis in this paper) in children and adolescents must be understood and investigated.MethodsData were extracted from the GBD database, and calculations were performed at global, regional, and national level. We calculate the incidence, prevalence, and disability-adjusted life years (DALYs) and annual average percentage changes (AAPCs).FindingsGlobally, the prevalent cases of children and adolescents with hepatitis B-associated cirrhosis decreased from 125,053.98 × 10^3 in 1990 to 46,400.33 × 10^3 in 2019. Compared with 1990, the incidence rate of cirrhosis increased in low (95.51%) and low-middle SDI areas (26.47%), whereas it decreased in other SDI areas. The AAPC of incidence has increased in low-middle SDI areas (AAPC 0.12 [95% CI: 0.04–0.20]). At the regional level, the East Asia region has experienced the largest reduction. Conversely, Western Sub-Saharan Africa was the most serious region. Notably, South Asia was the only region where the AAPC of cirrhosis incidence (AAPC 0.77 [95% CI, 0.68–0.86]) increased.ConclusionGlobally, the overall burden of hepatitis B-associated cirrhosis in children and adolescents has declined significantly, but the number of cirrhosis incidence cases in low-middle and low-SDI areas has increased. The incidence in South Asia is rising, and the burden on Africa remains serious. Prevention and treatment of hepatitis B-associated cirrhosis in children and adolescents should not be ignored.</p

Additional file 1 of Gut microbiota, circulating cytokines and dementia: a Mendelian randomization study

Additional file 1: The plots of MR analysis results

Highly Dispersed PdNi Nanoparticles on an Oxygen-Functionalized Activated Carbon with Extraordinary Electrocatalytic Activity for Methanol Oxidation

Exploration of advanced electrocatalysts with high activity and durability for the methanol oxidation reaction (MOR) is essential for developing high-efficiency and low-cost direct methanol fuel cells (DMFCs). Here, PdNi electrocatalysts with various Pd-to-Ni atomic ratios and high dispersion were prepared by a simple chemical reduction with functionalized activated carbon (FAC) and sodium borohydride as a support and a reducing agent, respectively. Among the various PdxNiy/FAC and the reference Pd/FAC catalysts, Pd4Ni1/FAC displays the highest catalytic activity toward methanol oxidation reaction (MOR) in an alkaline medium. Specifically, it achieves a high mass activity of up to 2577.5 mA/mgPd. In addition, it also shows high anti-CO poisoning and better stability. The superior electrocatalytic performance of Pd4Ni1/FAC may be attributed to the high dispersion and the synergic effect between Pd and Ni

Autophagy regulates T lymphocyte proliferation through selective degradation of the cell-cycle inhibitor CDKN1B/p27Kip1

<p>The highly conserved cellular degradation pathway, macroautophagy, regulates the homeostasis of organelles and promotes the survival of T lymphocytes. Previous results indicate that <i>Atg3-</i>, <i>Atg5</i>-, or <i>Pik3c3/Vps34</i>-deficient T cells cannot proliferate efficiently. Here we demonstrate that the proliferation of <i>Atg7</i>-deficient T cells is defective. By using an adoptive transfer and <i>Listeria monocytogenes</i> (LM) mouse infection model, we found that the primary immune response against LM is intrinsically impaired in autophagy-deficient CD8⁺ T cells because the cell population cannot expand after infection. Autophagy-deficient T cells fail to enter into S-phase after TCR stimulation. The major negative regulator of the cell cycle in T lymphocytes, CDKN1B, is accumulated in autophagy-deficient naïve T cells and CDKN1B cannot be degraded after TCR stimulation. Furthermore, our results indicate that genetic deletion of one allele of CDKN1B in autophagy-deficient T cells restores proliferative capability and the cells can enter into S-phase after TCR stimulation. Finally, we found that natural CDKN1B forms polymers and is physiologically associated with the autophagy receptor protein SQSTM1/p62 (sequestosome 1). Collectively, autophagy is required for maintaining the expression level of CDKN1B in naïve T cells and selectively degrades CDKN1B after TCR stimulation.</p

Tuning the Surface Alloy Composition of Phosphorus-Promoted Ni–Co Bimetallic Nanoparticles for Selective Tandem Hydrogenation

Selective tandem hydrogenation is a promising strategy for catalytic conversion of bulk raw materials with multifunctional groups into high-value-added chemicals via multiple-step reactions. Yet now, one of the current challenges is to develop a multifunctional and stable catalyst enabling the tandem catalysis rather than interrupting at any step reaction, particularly for supported nonprecious metal catalysts. In this work, we report tandem hydrogenation of bulk phthalic anhydride toward the one-pot synthesis of hexahydrophthalide, an emerging monomer of a recyclable polyester, over phosphorus-promoted Ni–Co bimetallic alloy nanoparticle catalysts. The surface composition of catalysts can be easily regulated by changing the Ni/Co molar ratio and the phosphorous functionalization strategy, which could then tune the product selectivity and enhance the stability of this tandem process. The optimal Ni3Co1@NC-P affords 88% selectivity for the desired product and demonstrates promising stability toward the tandem hydrogenation reaction. Systematic experimental and computational studies reveal that the adsorption strength of the intermediates and the ability of hydrogen activation can be altered by the formation of surface metallic Ni species, thus tuning the product selectivity. In addition, the oxidation resistance of Ni3Co1@NC-P was enhanced by the phosphorization treatment, which makes the bimetallic alloy successfully realize the tandem hydrogenation reaction. The finding of this work not only provides a convenient strategy to design and develop efficient and stable non-noble metal-based catalysts for selective tandem hydrogenation reactions, especially involving the hydrodeoxygenation reaction, but also fulfills the straightforward pathway for the preparation of degradable polyester monomer hexahydrophthalide

Development of High-Performance Biodegradable Rigid Polyurethane Foams Using Full Modified Soy-Based Polyols

Fossil fuel resources depletion and growing concern about environmental issues have raised the demand for newly sustainable biomaterials. To address this challenge, a new type of biodegradable and environmental rigid polyurethane foam called rigid polyurethane foams (RPUF)-M from full modified soy-based polyols have been synthesized without the addition of petroleum-based polyols. On the basis of the analysis of structure–activity relationship, a new kind of biobased polyurethane polyols called Bio-polyol-M was designed and synthesized directly from epoxidized soybean oil and a novel polyhydroxy compound in a three-step continuous microflow system. In the continuous microflow system, the epoxidation of soybean oil, the synthesis of GLPO (glycerine with styrene oxide), and the ring-opening reaction of epoxidized soybean oil were coupled. Another soy-polyol called Bio-polyol-B was synthesized in batch mode. In comparison to those of Bio-polyol-B, Bio-polyol-M had a higher hydroxyl number and a much lower viscosity. The RPUF-M also possessed a series of advantages over the rigid polyurethane foam called RPUF-B from Bio-polyol-B

Distribution of factors significantly associated with LSM failure.

<p>Patients’ percentage distribution according to the factors associated with LSM failure is showed (A), and the significances were determined by univariate and multivariate analyses (B). Intercostal space (IS).</p

Understanding Alkali Cation-Assisted Ring-Opening Polymerization of Macrocyclic Carbonate: Kinetics and Thermodynamics

Control over polymerization thermodynamics and kinetics enables the generation of polymers with on-demand properties. This is exemplified by the ring-opening polymerization of tetraethylene glycol carbonate (4EGMC) using an alkali cation (M+)-based binary catalytic system at ambient temperature. By introducing a guanidine catalyst [(1,5,7-triazabicyclo[4.4.0]dec-5-ene), TBD], the alkali cation-assisted ring-opening polymerization of macrocyclic carbonate was ca. 120–270 times faster than the reaction without an alkali cation, M+ (0.16–0.36 min–1 with M+ vs 0.001 min–1 without M+). Moreover, the interaction between 4EGMC and M+ led to an increase in the ring strain, supported by both bench experiments and computational simulations. This interaction altered the driving force of polymerization from the change of entropy to enthalpy, which revealed the pivotal role of alkali cations in regulating the ring-opening polymerization of macrocyclic carbonate