Association between birth weight and insulin resistance in US adolescents: A retrospective cohort study exploring the role of concurrent body mass index.

BACKGROUND AND AIMS: This study aimed to investigate the association between birth weight (BW) and abnormal HOMA-IR in US adolescents aged 12-15 years. The role of concurrent body mass index (BMI) in adolescence was also examined. METHODS AND RESULTS: This retrospective cohort study included 3429 participants from NHANES with data in 1999-2020. HOMA-IR ≥2.3 was considered abnormal. Participants were classified as low (LBW; <2.5 kg), normal (NBW; 2.5-4.0 kg), or high (HBW; >4.0 kg) BW. Logistic regression was used to explore the association between BW and HOMA-IR. Mediation analysis was used to examine whether BMI z-score in adolescence mediated the association between BW and HOMA-IR. Compared with those in NBW, the odds ratios (95 % CI) of abnormal HOMA-IR in LBW and HBW groups were 1.26 (0.99-1.60), and 0.62 (0.47-0.83) respectively. The association between BW and abnormal HOMA-IR was consistent in all subgroups with no significant interactions. Mediation analysis showed that BW is associated with lower risk of HOMA-IR directly, but with higher risk indirectly via BMI in adolescence. CONCLUSION: There was a negative linear relationship between BW and the prevalence of abnormal HOMA-IR in adolescents aged 12-15 independent of concurrent BMI. Children who were born with LBW but had high BMI in adolescence were of particularly higher risk of insulin resistance.

A DFT study of boron nitride-confined nickel single atoms for the oxidation of methane to methanol.

Direct oxidation of methane to methanol (DMTM) remains an economically tantalizing but fundamentally challenging goal because of the highly stable C-H bonds. By using density functional theory calculations, we investigated the catalytic properties of single transition metals (Fe, Pd, Ni) supported on O-doped BN in different coordination environments for DMTM. The results indicated that embedding Ni into O-doped BN via two N atoms and one O atom coordination (Ni1/O1N2-BN) was an efficient option for DMTM. Ni1/O1N2-BN was capable of effectively activating the strong C-H bonds of CH4 by generating key Ni-O intermediates. Besides, Ni1/O1N2-BN also exhibited high selectivity for CH3OH owing to the inhibition of CH2 competitive species and low desorption energy of CH3OH. Furthermore, the excellent thermal stability of Ni1/O1N2-BN was verified via ab initio molecular dynamics calculations at 500 K for 10 ps. This work provides a new insight into the fundamental understanding and materials design of high-efficiency catalysts for DMTM.

Photocatalytic Conversion of Methane: Recent Advancements and Prospects.

Abundant and affordable methane is not only a high-quality fossil fuel, it is also a raw material for the synthesis of value-added chemicals. Solar-energy-driven conversion of methane offers a promising approach to directly transform methane to valuable energy sources under mild conditions, but remains a great challenge at present. In this Review, recent advances in the photocatalytic conversion of methane are systematically summarized. Insights into the construction of effective semiconductor-based photocatalysts from the perspective of light-absorption units and active centers are highlighted and discussed in detail. The performance of various photocatalysts in the conversion of methane is presented, with the photooxidation classified according to the oxidant systems. Lastly, challenges and future perspectives in the photocatalytic oxidation of methane are described.

Pt Single Atoms Embedded in the Surface of Ni Nanocrystals as Highly Active Catalysts for Selective Hydrogenation of Nitro Compounds.

Single-atom catalysts exhibit high selectivity in hydrogenation due to their isolated active sites, which ensure uniform adsorption configurations of substrate molecules. Compared with the achievement in catalytic selectivity, there is still a long way to go in exploiting the catalytic activity of single-atom catalysts. Herein, we developed highly active and selective catalysts in selective hydrogenation by embedding Pt single atoms in the surface of Ni nanocrystals (denoted as Pt1/Ni nanocrystals). During the hydrogenation of 3-nitrostyrene, the TOF numbers based on surface Pt atoms of Pt1/Ni nanocrystals reached ∼1800 h-1 under 3 atm of H2 at 40 °C, much higher than that of Pt single atoms supported on active carbon, TiO2, SiO2, and ZSM-5. Mechanistic studies reveal that the remarkable activity of Pt1/Ni nanocrystals derived from sufficient hydrogen supply because of spontaneous dissociation of H2 on both Pt and Ni atoms as well as facile diffusion of H atoms on Pt1/Ni nanocrystals. Moreover, the ensemble composed of the Pt single atom and nearby Ni atoms in Pt1/Ni nanocrystals leads to the adsorption configuration of 3-nitrostyrene favorable for the activation of nitro groups, accounting for the high selectivity for 3-vinylaniline.

Integration of Quantum Confinement and Alloy Effect to Modulate Electronic Properties of RhW Nanocrystals for Improved Catalytic Performance toward CO2 Hydrogenation.

The d-band center and surface negative charge density generally determine the adsorption and activation of CO2, thus serving as important descriptors of the catalytic activity toward CO2 hydrogenation. Herein, we engineered the d-band center and negative charge density of Rh-based catalysts by tuning their dimensions and introducing non-noble metals to form an alloy. During the hydrogenation of CO2 into methanol, the catalytic activity of Rh75W25 nanosheets was 5.9, 4.0, and 1.7 times as high as that of Rh nanoparticles, Rh nanosheets, and Rh73W27 nanoparticles, respectively. Mechanistic studies reveal that the remarkable activity of Rh75W25 nanosheets is owing to the integration of quantum confinement and alloy effect. Specifically, the quantum confinement in one dimension shifts up the d-band center of Rh75W25 nanosheets, strengthening the adsorption of CO2. Moreover, the alloy effect not only promotes the activation of CO2 to form CO2δ- but also enhances the adsorption of intermediates to facilitate further hydrogenation of the intermediates into methanol.

Integration of Photothermal Effect and Heat Insulation to Efficiently Reduce Reaction Temperature of CO2 Hydrogenation.

The photothermal effect is applied in CO2 hydrogenation to reduce the reaction temperature under illumination by encapsulating Pt nanocubes and Au nanocages into a zeolitic imidazolate framework (ZIF-8). Under illumination, the heat generated by the photothermal effect of Au nanocages is mainly insulated in the ZIF-8 to form a localized high-temperature region, thereby improving the catalytic activity of Pt nanocubes.

Supported Rhodium Catalysts for Ammonia-Borane Hydrolysis: Dependence of the Catalytic Activity on the Highest Occupied State of the Single Rhodium Atoms.

Supported metal nanocrystals have exhibited remarkable catalytic performance in hydrogen generation reactions, which is influenced and even determined by their supports. Accordingly, it is of fundamental importance to determine the direct relationship between catalytic performance and metal-support interactions. Herein, we provide a quantitative profile for exploring metal-support interactions by considering the highest occupied state in single-atom catalysts. The catalyst studied consisted of isolated Rh atoms dispersed on the surface of VO2 nanorods. It was observed that the activation energy of ammonia-borane hydrolysis changed when the substrate underwent a phase transition. Mechanistic studies indicate that the catalytic performance depended directly on the highest occupied state of the single Rh atoms, which was determined by the band structure of the substrates. Other metal catalysts, even with non-noble metals, that exhibited significant catalytic activity towards NH3 BH3 hydrolysis were rationally designed by adjusting their highest occupied states.

Aerobic Oxidation of Cyclohexane on Catalysts Based on Twinned and Single-Crystal Au75Pd25 Bimetallic Nanocrystals.

Bimetallic Au75Pd25 nanocrystals with shapes of icosahedron and octahedron were synthesized by adding different amounts of iodide ions, and were employed as catalysts for solvent-free aerobic oxidation of cyclohexane. Although both icosahedrons and octahedrons were bounded by {111} facets, the turnover frequency number of Au75Pd25 icosahedrons reached 15,106 h(-1), almost three times as high as that of Au75Pd25 octahedrons. The conversion of cyclohexane reached 28.1% after 48 h using Au75Pd25 icosahedrons, with the selectivity of 84.3% to cyclohexanone. Density functional theory calculations along with X-ray photoelectron spectroscopy examinations reveal that the excellent catalytic performance of AuPd icosahedrons could be ascribed to twin-induced strain and highly negative charge density of Au atoms on the surface.

Pt3 Co Octapods as Superior Catalysts of CO2 Hydrogenation.

As the electron transfer to CO2 is a critical step in the activation of CO2 , it is of significant importance to engineer the electronic properties of CO2 hydrogenation catalysts to enhance their activity. Herein, we prepared Pt3 Co nanocrystals with improved catalytic performance towards CO2 hydrogenation to methanol. Pt3 Co octapods, Pt3 Co nanocubes, Pt octapods, and Pt nanocubes were tested, and the Pt3 Co octapods achieved the best catalytic activity. Both the presence of multiple sharp tips and charge transfer between Pt and Co enabled the accumulation of negative charges on the Pt atoms in the vertices of the Pt3 Co octapods. Moreover, infrared reflection absorption spectroscopy confirmed that the high negative charge density at the Pt atoms in the vertices of the Pt3 Co octapods promotes the activation of CO2 and accordingly enhances the catalytic activity.

Ratio-controlled synthesis of CuNi octahedra and nanocubes with enhanced catalytic activity.

Non-noble bimetallic nanocrystals (NCs) have been widely explored due to not only their low cost and abundant content in the Earth's crust but also their outstanding performance in catalytic reactions. However, controllable synthesis of non-noble alloys remains a significant challenge. Here we report a facile synthesis of CuNi octahedra and nanocubes with controllable shapes and tunable compositions. Its success relies on the use of borane morpholine as a reducing agent, which upon decomposition generates a burst of H2 molecules to induce rapid formation of the nuclei. Specifically, octahedra switched to nanocubes with an increased amount of borane morpholine. In addition, the ratio of CuNi NCs could be facilely tuned by changing the molar ratio of both precursors. The obtained CuNi NCs exhibited high activity in aldehyde-alkyne-amine coupling reactions, and their performance is strongly facet- and composition-dependent due to the competition of the surface energy (enhanced by increasing the percent of Ni) and active sites (derived from Cu atoms).

Fetal Hyperthyroidism with Maternal Hypothyroidism: Two Cases of Intrauterine Therapy.

Fetal hyperthyroidism can occur secondary to maternal autoimmune hyperthyroidism. The thyroid-stimulating hormone receptor antibody (TRAb) transferred from the mother to the fetus stimulates the fetal thyroid and causes fetal thyrotoxicosis. Fetuses with this condition are difficult to detect, especially after maternal Graves disease therapy. Here, we present two cases of fetal hyperthyroidism with maternal hypothyroidism and review the assessment and intrauterine therapy for fetal hyperthyroidism. Both women were referred at 22+ and 23+ weeks of gestation with abnormal ultrasound findings, including fetal heart enlargement, pericardial effusion, and fetal tachycardia. Both women had a history of Graves disease while in a state of hypothyroidism with a high titer of TRAb. A sonographic examination showed a diffusely enlarged fetal thyroid with abundant blood flow. Invasive prenatal testing revealed no significant chromosomal aberration. Low fetal serum TSH and high TRAb levels were detected in the cord blood. Fetal hyperthyroidism was considered, and maternal oral methimazole (MMI) was administered as intrauterine therapy, with the slowing of fetal tachycardia, a reduction in fetal heart enlargement, and thyroid hyperemia. During therapy, maternal thyroid function was monitored, and the dosage of maternal levothyroxine was adjusted accordingly. Both women delivered spontaneously at 36+ weeks of gestation, and neonatal hyperthyroidism was confirmed in both newborns. After methimazole and propranolol drug treatment with levothyroxine for 8 and 12 months, both babies became euthyroid with normal growth and development.

A new nanobiocatalytic system based on allosteric effect with dramatically enhanced enzymatic performance.

We report a rational design of CaHPO(4)-α-amylase hybrid nanobiocatalytic system based on allosteric effect and an explanation of the increase in catalytic activity when certain enzymes are immobilized in specific nanomaterials. Employing a calcification approach in aqueous solutions, we acquired such new nanobiocatalytic systems with three different morphologies, i.e., nanoflowers, nanoplates, and parallel hexahedrons. Through studying enzymatic performance of these systems and free α-amylase with/without Ca(2+), we demonstrated how two factors, allosteric regulation and morphology of the as-synthesized nanostructures, predominantly influence enzymatic activity. Benefiting from both the allosteric modulation and its hierarchical structure, CaHPO(4)-α-amylase hybrid nanoflowers exhibited dramatically enhanced enzymatic activity. As a bonus, the new system we devised was found to enjoy higher stability and durability than free α-amylase plus Ca(2+).

Symmetric and asymmetric Au-AgCdSe hybrid nanorods.

This paper describes a facile method for synthesis of Au-AgCdSe hybrid nanorods with controlled morphologies and spatial distributions. The synthesis involved deposition of Ag tips at the ends of Au nanorod seeds, followed by selenization of the Ag tips and overgrowth of CdSe on these sites. By simply manipulating the pH value of the system, the AgCdSe could selectively grow at one end, at both the ends or on the side surface of a Au nanorod, generating a mike-like, dumbbell-like, or toothbrush-like hybrid nanorod, respectively. These three types of Au-AgCdSe hybrid nanorods displayed distinct localized surface plasmon resonance and photoluminescence properties, demonstrating an effective pathway for maneuvering the optical properties of nanocrystals.

Constructing imine groups on the surface of Cu1/Pd(111) as a novel strategy for CO2 hydrogenation to methanol.

Developing a promising strategy to improve the limited selectivity and activity of traditional Pd-Cu bimetallic catalysts for CO2 hydrogenation to methanol (CH3OH) remains a grand challenge. By using density functional theory calculations, we discovered that introducing imine groups on the Cu1/Pd(111) surface through a condensation reaction of aldehydes and amines is an intriguing approach for simultaneously enhancing the selectivity and activity of Cu1/Pd(111) for CO2 hydrogenation to CH3OH. The imine groups formed by amino reactions with acrolein on the Cu1/Pd(111) surface (C3H4O@NH2-Cu1/Pd(111)) improved the turnover frequency (TOF). The imine group optimized the electronic structure of active sites and increased electron transfer to the anti-bonding orbital of CO2, facilitating the activity of C3H4O@NH2-Cu1/Pd(111) for CO2 hydrogenation to CH3OH. Besides, the inhibition of CO by-products and the low desorption energy of CH3OH were responsible for the high selectivity of C3H4O@NH2-Cu1/Pd(111) for CH3OH. This work advances our understanding of the role of imines in catalysis and provides a new strategy for designing excellent functional group-modified catalysts for the hydrogenation of CO2 to CH3OH.

Direct conversion of methane to methanol on boron nitride-supported copper single atoms.

Direct conversion of methane to methanol (DMTM) under mild conditions is one of the most attractive and challenging processes in catalysis. By using density functional theory calculations, we systematically investigate the catalytic performance of Cu single atoms supported on O-doped BN in different coordination environments as a DMTM catalyst. Computations demonstrate that Cu coordinated with one O atom and two N atoms on O-doped BN (Cu1/O1N2-BN) exhibited the highest catalytic activity for DMTM at room temperature with quite a low rate-determining step energy barrier of 0.46 eV. The moderate adsorption of *O atoms, selective stabilization of CH3 species, and easy desorption of CH3OH are responsible for the unique activity of Cu1/O1N2-BN for DMTM. In addition, the adsorption free energy of *O atoms produced by the dissociation of O-donor molecules is a suitable descriptor for predicting the catalytic performance of materials and accelerating the discovery of catalysts for DMTM. This work opens new avenues to develop highly efficient catalysts for DMTM.

Enhanced uranium photoreduction on Ti3C2Tx MXene by modulation of surface functional groups and deposition of plasmonic metal nanoparticles.

Photocatalytic reduction of soluble hexavalent uranium (U(VI)) is a novel and efficient avenue to enriching U(VI), where the free U(VI) is firstly bound on the surface of photocatalysts and then reduced to insoluble tetravalent uranium (U(IV)) by photoelectrons. Therefore, constructing the efficient U(VI) binding sites on photocatalysts is an efficient strategy to boost catalytic activity toward U(VI) photoreduction. Herein, we successfully constructed an efficient catalyst for U(VI) photoreduction by depositing Ag nanoparticles on Ti3C2Tx MXene with abundant U(VI) binding sites (Ag/Ti3C2Tx-O). Impressively, the U(VI) extracting mass over Ag/Ti3C2Tx-O under light reached up to 1257.6 mg/g in 120 min, which was almost 11 times as high as that without light. Further mechanistic studies indicated that the U(VI) binding sites on Ti3C2Tx MXene in Ag/Ti3C2Tx-O were beneficial to the reduction of U(VI) by significantly decreasing its reduction potential. More importantly, hot electrons generated by Ag nanoparticles were transferred into the binding sites to easily reduce the bound U(VI), resulting in the remarkable performance of Ag/Ti3C2Tx-O during U(VI) enrichment.

Copper-Based Plasmonic Catalysis: Recent Advances and Future Perspectives.

With the capability of inducing intense electromagnetic field, energetic charge carriers, and photothermal effect, plasmonic metals provide a unique opportunity for efficient light utilization and chemical transformation. Earth-abundant low-cost Cu possesses intense and tunable localized surface plasmon resonance from ultraviolet-visible to near infrared region. Moreover, Cu essentially exhibits remarkable catalytic performance toward various reactions owing to its intriguing physical and chemical properties. Coupling with light-harvesting ability and catalytic function, plasmonic Cu serves as a promising platform for efficient light-driven chemical reaction. Herein, recent advancements of Cu-based plasmonic photocatalysis are systematically summarized, including designing and synthetic strategies for Cu-based catalysts, plasmonic catalytic performance, and mechanistic understanding over Cu-based plasmonic catalysts. What's more, approaches for the enhancement of light utilization efficiency and construction of active centers on Cu-based plasmonic catalysts are highlighted and discussed in detail, such as morphology and size control, regulation of electronic structure, defect and strain engineering, etc. Remaining challenges and future perspectives for further development of Cu-based plasmonic catalysis are also proposed.

Copper-Stabilized P'2-Type Layered Manganese Oxide Cathodes for High-Performance Sodium-Ion Batteries.

Layered sodium manganese oxides are promising low-cost and high-capacity cathode materials for commercialization of sodium-ion batteries (SIBs). P'2-type Na0.67MnO2 with an orthorhombic structure has been considered as a significant candidate for SIBs. However, the Jahn-Teller distortion and undesired phase transitions will lead to poor structural stability and unsatisfactory cycling performance. Herein, a systematic investigation on partially copper-doped P'2-type Na0.67CuxMn1-xO2 (x = 0, 0.05, 0.1, and 0.2) series as cathodes for SIBs reveals the relationship between doping concentrations and Na storage properties. With proper copper content, P'2 Na0.67Cu0.1Mn0.9O2 exhibits a suppressed Jahn-Teller effect as well as relatively less phase transitions, which can deliver a high specific capacity of 222.7 mA h g-1 at 10 mA g-1 within 1.5-4.2 V, with a capacity retention of 76% at 1 A g-1 after 300 cycles. The electrochemical mechanism is systematically investigated via in situ X-ray diffraction observations and density functional theory calculations, which provide fundamental guidelines for developing high-performance cathodes for SIBs.

Structural determinants of substrate recognition in the HAD superfamily member D-glycero-D-manno-heptose-1,7-bisphosphate phosphatase (GmhB) .

The haloalkanoic acid dehalogenase (HAD) enzyme superfamily is the largest family of phosphohydrolases. In HAD members, the structural elements that provide the binding interactions that support substrate specificity are separated from those that orchestrate catalysis. For most HAD phosphatases, a cap domain functions in substrate recognition. However, for the HAD phosphatases that lack a cap domain, an alternate strategy for substrate selection must be operative. One such HAD phosphatase, GmhB of the HisB subfamily, was selected for structure-function analysis. Herein, the X-ray crystallographic structures of Escherichia coli GmhB in the apo form (1.6 A resolution), in a complex with Mg(2+) and orthophosphate (1.8 A resolution), and in a complex with Mg(2+) and d-glycero-d-manno-heptose 1beta,7-bisphosphate (2.2 A resolution) were determined, in addition to the structure of Bordetella bronchiseptica GmhB bound to Mg(2+) and orthophosphate (1.7 A resolution). The structures show that in place of a cap domain, the GmhB catalytic site is elaborated by three peptide inserts or loops that pack to form a concave, semicircular surface around the substrate leaving group. Structure-guided kinetic analysis of site-directed mutants was conducted in parallel with a bioinformatics study of sequence diversification within the HisB subfamily to identify loop residues that serve as substrate recognition elements and that distinguish GmhB from its subfamily counterpart, the histidinol-phosphate phosphatase domain of HisB. We show that GmhB and the histidinol-phosphate phosphatase domain use the same design of three substrate recognition loops inserted into the cap domain yet, through selective residue usage on the loops, have achieved unique substrate specificity and thus novel biochemical function.

Divergence of biochemical function in the HAD superfamily: D-glycero-D-manno-heptose-1,7-bisphosphate phosphatase (GmhB).

D-Glycero-d-manno-heptose-1,7-bisphosphate phosphatase (GmhB) is a member of the histidinol-phosphate phosphatase (HisB) subfamily of the haloalkanoic acid dehalogenase (HAD) enzyme superfamily. GmhB supports two divergent biochemical pathways in bacteria: the d-glycero-d-manno-heptose-1alpha-GDP pathway (in S-layer glycoprotein biosynthesis) and the l-glycero-d-manno-heptose-1beta-ADP pathway (in lipid A biosynthesis). Herein, we report the comparative analysis of substrate recognition in selected GmhB orthologs. The substrate specificity of the l-glycero-d-manno-heptose-1beta-ADP pathway GmhB from Escherichia coli K-12 was evaluated using hexose and heptose bisphosphates, histidinol phosphate, and common organophosphate metabolites. Only d-glycero-d-manno-heptose 1beta,7-bisphosphate (k(cat)/K(m) = 7 x 10(6) M(-1) s(-1)) and d-glycero-d-manno-heptose 1alpha,7-bisphosphate (k(cat)/K(m) = 7 x 10(4) M(-1) s(-1)) displayed physiologically significant substrate activity. (31)P NMR analysis demonstrated that E. coli GmhB selectively removes the C(7) phosphate. Steady-state kinetic inhibition studies showed that d-glycero-d-manno-heptose 1beta-phosphate (K(is) = 60 microM, and K(ii) = 150 microM) and histidinol phosphate (K(is) = 1 mM, and K(ii) = 6 mM), while not hydrolyzed, do in fact bind to E. coli GmhB, which leads to the conclusion that nonproductive binding contributes to substrate discrimination. High catalytic efficiency and a narrow substrate range are characteristic of a well-evolved metabolic enzyme, and as such, E. coli GmhB is set apart from most HAD phosphatases (which are typically inefficient and promiscuous). The specialization of the biochemical function of GmhB was examined by measuring the kinetic constants for hydrolysis of the alpha- and beta-anomers of d-glycero-d-manno-heptose 1beta,7-bisphosphate catalyzed by the GmhB orthologs of the l-glycero-d-manno-heptose 1beta-ADP pathways operative in Bordetella bronchiseptica and Mesorhizobium loti and by the GmhB of the d-glycero-d-manno-heptose 1alpha-GDP pathway operative in Bacteroides thetaiotaomicron. The results show that although each of these representatives possesses physiologically significant catalytic activity toward both anomers, each displays substantial anomeric specificity. Like E. coli GmhB, B. bronchiseptica GmhB and M. loti GmhB prefer the beta-anomer, whereas B. thetaiotaomicron GmhB is selective for the alpha-anomer. By determining the anomeric configuration of the physiological substrate (d-glycero-d-manno-heptose 1,7-bisphosphate) for each of the four GmhB orthologs, we discovered that the anomeric specificity of GmhB correlates with that of the pathway kinase. The conclusion drawn from this finding is that the evolution of the ancestor to GmhB in the HisB subfamily provided for specialization toward two distinct biochemical functions.