Myopia Control Effect of Repeated Low-Level Red-Light Therapy Combined with Orthokeratology: A Multicenter Randomized Controlled Trial.

PURPOSE: To investigate the efficacy and safety of repeated low-level red-light (RLRL) therapy combined with orthokeratology among children who, despite undergoing orthokeratology, exhibited an axial elongation of at least 0.50 mm over 1 year. DESIGN: Multicenter, randomized, parallel-group, single-blind clinical trial (ClinicaTrials.gov identifier, NCT04722874). PARTICIPANTS: Eligible children were 8-13 years of age with a cycloplegic spherical equivalent refraction of -1.00 to -5.00 diopters at the initial orthokeratology fitting examination and had annual axial length (AL) elongation of ≥0.50 mm despite undergoing orthokeratology. Forty-eight children were enrolled from March 2021 through January 2022, and the final follow-up was completed in March 2023. METHODS: Children were assigned randomly to the RLRL therapy combined with orthokeratology (RCO) group or to the orthokeratology group in a 2:1 ratio. The orthokeratology group wore orthokeratology lenses for at least 8 hours per night, whereas the RCO group received daily RLRL therapy twice daily for 3 minutes in addition to orthokeratology. MAIN OUTCOME MEASURES: The primary outcome was AL change measured at 12 months relative to baseline. The primary analysis was conducted in children who received the assigned intervention and completed at least 1 follow-up after randomization using the modified intention-to-treat principle. RESULTS: Forty-seven children (97.9%) were included in the analysis (30 in the RCO group and 17 in the orthokeratology group). The mean axial elongation rate before the trial was 0.60 mm/year and 0.61 mm/year in the RCO and orthokeratology groups, respectively. After 12 months, the adjusted mean AL changes were -0.02 mm (95% confidence interval [CI], -0.08 to +0.03 mm) in the RCO group and 0.27 mm (95% CI, 0.19-0.34 mm) in the orthokeratology group. The adjusted mean difference in AL change was -0.29 mm (95% CI, -0.44 to -0.14 mm) between the groups. The percentage of children achieving an uncorrected visual acuity of more than 20/25 was similar in the RCO (64.3%) and orthokeratology (65.5%) groups (P = 0.937). CONCLUSIONS: Combining RLRL therapy with orthokeratology may offer a promising approach to optimize axial elongation control among children with myopia. This approach also potentially allows children to achieve satisfactory visual acuity, reducing daytime dependence on corrective eyewear. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Retinal nerve fiber layer thinning as a novel fingerprint for cardiovascular events: results from the prospective cohorts in UK and China.

BACKGROUND: Retinal structural abnormalities have been found to serve as biomarkers for cardiovascular disease (CVD). However, the association between retinal nerve fiber layer (RNFL) thickness and the incidence of CVD events remains inconclusive, and relevant longitudinal studies are lacking. Therefore, we aimed to examine this link in two prospective cohort studies. METHODS: A total of 25,563 participants from UK Biobank who were initially free of CVD were included in the current study. Another 635 participants without retinopathy at baseline from the Chinese Guangzhou Diabetes Eye Study (GDES) were adopted as the validation set. Measurements of RNFL thickness in the macular (UK Biobank) and peripapillary (GDES) regions were obtained from optical coherence tomography (OCT). Adjusted hazard ratios (HRs), odd ratios (ORs), and 95% confidence intervals (CI) were calculated to quantify CVD risk. RESULTS: Over a median follow-up period of 7.67 years, 1281 (5.01%) participants in UK Biobank developed CVD events. Each 5-µm decrease in macular RNFL thickness was associated with an 8% increase in incident CVD risk (HR = 1.08, 95% CI: 1.01-1.17, p = 0.033). Compared with participants in the highest tertile of RNFL thickness, the risk of incident CVD was significantly increased in participants in the lowest thickness tertile (HR = 1.18, 95% CI: 1.01-1.38, p = 0.036). In GDES, 29 (4.57%) patients developed CVD events within 3 years. Lower average peripapillary RNFL thickness was also associated with a higher CVD risk (OR = 1.35, 95% CI: 1.11-1.65, p = 0.003). The additive net reclassification improvement (NRI) was 21.8%, and the absolute NRI was 2.0% by addition of RNFL thickness over the Framingham risk score. Of 29 patients with incident CVD, 7 were correctly reclassified to a higher risk category while 1 was reclassified to a lower category, and 21 high risk patients were not reclassified. CONCLUSIONS: RNFL thinning was independently associated with increased incident cardiovascular risk and improved reclassification capability, indicating RNFL thickness derived from the non-invasive OCT as a potential retinal fingerprint for CVD event across ethnicities and health conditions. TRIAL REGISTRATION: ISRCTN 15853192.

Association of Retinal Age Gap and Risk of Kidney Failure: A UK Biobank Study.

RATIONALE & OBJECTIVE: The incidence of kidney failure is known to increase with age. We have previously developed and validated the use of retinal age based on fundus images as a biomarker of aging. However, the association of retinal age with kidney failure is not clear. We investigated the association of retinal age gap (the difference between retinal age and chronological age) with future risk of kidney failure. STUDY DESIGN: Prospective cohort study. SETTING & PARTICIPANTS: 11,052 UK Biobank study participants without any reported disease for characterizing retinal age in a deep learning algorithm. 35,864 other participants with retinal images and no kidney failure were followed to assess the association between retinal age gap and the risk of kidney failure. EXPOSURE: Retinal age gap, defined as the difference between model-based retinal age and chronological age. OUTCOME: Incident kidney failure. ANALYTICAL APPROACH: A deep learning prediction model used to characterize retinal age based on retinal images and chronological age, and Cox proportional hazards regression models to investigate the association of retinal age gap with incident kidney failure. RESULTS: After a median follow-up period of 11 (IQR, 10.89-11.14) years, 115 (0.32%) participants were diagnosed with incident kidney failure. Each 1-year greater retinal age gap at baseline was independently associated with a 10% increase in the risk of incident kidney failure (HR, 1.10 [95% CI, 1.03-1.17]; P=0.003). Participants with retinal age gaps in the fourth (highest) quartile had a significantly higher risk of incident kidney failure compared with those in the first quartile (HR, 2.77 [95% CI, 1.29-5.93]; P=0.009). LIMITATIONS: Limited generalizability related to the composition of participants in the UK Biobank study. CONCLUSIONS: Retinal age gap was significantly associated with incident kidney failure and may be a promising noninvasive predictive biomarker for incident kidney failure.

Longitudinal Changes and Predictive Value of Choroidal Thickness for Myopia Control after Repeated Low-Level Red-Light Therapy.

PURPOSE: To evaluate longitudinal changes in macular choroidal thickness (mCT) in myopic children treated for 1 year with repeated low-level red-light (RLRL) therapy and their predictive value for treatment efficacy on myopia control. DESIGN: A secondary analysis of data from a multicenter, randomized controlled trial (RCT; NCT04073238). PARTICIPANTS: Myopic children aged 8-13 years who participated in the RCT at 2 of 5 sites where mCT measurements were available. METHODS: Repeated low-level red-light therapy was delivered using a home-use desktop light device that emitted red-light at 650 nm. Choroidal thickness was measured by SS-OCT at baseline and 1-, 3-, 6-, and 12-month follow-ups. Visual acuity, axial length (AL), cycloplegic spherical equivalent refraction (SER), and treatment compliance were measured. MAIN OUTCOME MEASURES: Changes in mCT at 1, 3, 6, and 12 months relative to baseline, and their associations with myopia control. RESULTS: A total of 120 children were included in the analysis (RLRL group: n = 60; single-vision spectacle [SVS] group: n = 60). Baseline characteristics were well balanced between the 2 groups. In the RLRL group, changes in mCT from baseline remained positive over 1 year, with a maximal increase of 14.755 µm at 1 month and gradually decreasing from 5.286 µm at 3 months to 1.543 µm at 6 months, finally reaching 9.089 µm at 12 months. In the SVS group, mCT thinning was observed, with changes from baseline of -1.111, -8.212, -10.190, and -10.407 µm at 1, 3, 6, and 12 months, respectively. Satisfactory myopia control was defined as annual progression rates of less than 0, 0.05, or 0.10 mm for AL and less than 0, 0.25, or 0.50 diopters for SER. Models that included mCT changes at 3 months alone had acceptable predictive discrimination of satisfactory myopia control over 12 months, with areas under the curve of 0.710-0.786. The predictive performance of the models did not significantly improve after adding age, gender, and baseline AL or SER. CONCLUSIONS: This analysis from a multicenter RCT found RLRL induced sustained choroidal thickening over the full course of treatment. Macular choroidal thickness changes at 3 months alone can predict 12-month myopia control efficacy with reasonable accuracy. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found after the references.

Retinal age gap as a predictive biomarker of future risk of Parkinson's disease.

INTRODUCTION: retinal age derived from fundus images using deep learning has been verified as a novel biomarker of ageing. We aim to investigate the association between retinal age gap (retinal age-chronological age) and incident Parkinson's disease (PD). METHODS: a deep learning (DL) model trained on 19,200 fundus images of 11,052 chronic disease-free participants was used to predict retinal age. Retinal age gap was generated by the trained DL model for the remaining 35,834 participants free of PD at the baseline assessment. Cox proportional hazards regression models were utilised to investigate the association between retinal age gap and incident PD. Multivariable logistic model was applied for prediction of 5-year PD risk and area under the receiver operator characteristic curves (AUC) was used to estimate the predictive value. RESULTS: a total of 35,834 participants (56.7 ± 8.04 years, 55.7% female) free of PD at baseline were included in the present analysis. After adjustment of confounding factors, 1-year increase in retinal age gap was associated with a 10% increase in risk of PD (hazard ratio [HR] = 1.10, 95% confidence interval [CI]: 1.01-1.20, P = 0.023). Compared with the lowest quartile of the retinal age gap, the risk of PD was significantly increased in the third and fourth quartiles (HR = 2.66, 95% CI: 1.13-6.22, P = 0.024; HR = 4.86, 95% CI: 1.59-14.8, P = 0.005, respectively). The predictive value of retinal age and established risk factors for 5-year PD risk were comparable (AUC = 0.708 and 0.717, P = 0.821). CONCLUSION: retinal age gap demonstrated a potential for identifying individuals at a high risk of developing future PD.

PROGRESSIVE PERIPAPILLARY CHOROID THINNING AND RETINAL NEURODEGENERATION IN PATIENTS WITH DIABETES: A 3-Year Cohort Study.

PURPOSE: To investigate longitudinal changes in peripapillary choroidal thickness (pCT) and retinal nerve fiber thickness (pRNFLT) in patients with Type 2 diabetes mellitus. METHODS: This was a prospective observational cohort study. Patients with Type 2 diabetes mellitus without diabetic retinopathy (DR) at baseline were recruited, followed up for three years, and further divided into an incident DR group and a non-DR group according to the outcome. The pCT and pRNFLT were measured through swept-source optical coherence tomography at 1-year interval, and the mean rates of pCT and pRNFLT thinning were compared between the DR groups. RESULTS: A total of 682 patients (682 eyes) were included in the final analysis. After 3-years follow-up, 122 (17.89%) developed DR. Both pCT and pRNFLT progressively thinned (-2.37 [-2.80 to -1.95] µm/year; -0.40 [-0.55 to -0.25] µm/year, respectively, P < 0.05) and accelerated thinning was observed in the incident DR group. The rates of pCT thinning (-3.92 [-4.96 to -2.88] µm/year, -2.03 [-2.49 to -1.57] µm/year, respectively) and pRNFLT loss (-1.03 [-1.31 to -0.76] µm/year, -0.26 [-0.43 to -0.09] µm/year, respectively) in the incident DR group were 1.93 and 3.96 times faster than those in the non-DR group, respectively. In addition, pCT and pRNFLT thinning were negatively related in Type 2 diabetes mellitus population, and faster pCT thinning indicated slower pRNFLT loss. CONCLUSION: Patients with Type 2 diabetes mellitus were at a higher risk of developing DR when accelerated pCT and pRNFLT thinning were present, indicating that heavier choroidal damage and retinal neurodegeneration precede clinical DR. The pCT and pRNFLT have the potential to serve as novel sensitive biomarkers of preclinical and early DR.

Sustained and rebound effect of repeated low-level red-light therapy on myopia control: A 2-year post-trial follow-up study.

BACKGROUND: To evaluate the long-term efficacy and safety of continued repeated low-level red-light (RLRL) therapy on myopia control over 2 years, and the potential rebound effect after treatment cessation. METHODS: The Chinese myopic children who originally completed the one-year randomised controlled trial were enrolled. Children continued RLRL-therapy were defined as RLRL-RLRL group, while those who stopped and switched to single-vision spectacle (SVS) in the second year were RLRL-SVS group. Likewise, those who continued to merely wear SVS or received additional RLRL-therapy were SVS-SVS and SVS-RLRL groups, respectively. RLRL-therapy was provided by an at-home desktop light device emitting red-light of 650 nm and was administered for 3 min at a time, twice a day and 5 days per week. Changes in axial length (AL) and cycloplegic spherical equivalence refraction (SER) were measured. RESULTS: Among the 199 children who were eligible, 138 (69.3%) children attended the examination and 114 (57.3%) were analysed (SVS-SVS: n = 41; SVS-RLRL: n = 10; RLRL-SVS: n = 52; RLRL-RLRL: n = 11). The baseline characteristics were balanced among four groups. In the second year, the mean changes in AL were 0.28 ± 0.14 mm, 0.05 ± 0.24 mm, 0.42 ± 0.20 mm and 0.12 ± 0.16 mm in SVS-SVS, SVS-RLRL, RLRL-SVS and RLRL-RLRL group, respectively (p < 0.001). The respective mean SER changes were -0.54 ± 0.39D, -0.09 ± 0.55D, -0.91 ± 0.48D, and -0.20 ± 0.56D (p < 0.001). Over the 2-year period, axial elongation and SER progression were smallest in RLRL-RLRL group (AL: 0.16 ± 0.37 mm; SER: -0.31 ± 0.79D), followed by SVS-RLRL (AL: 0.44 ± 0.37 mm; SER: -0.96 ± 0.70D), RLRL-SVS (AL: 0.50 ± 0.28 mm; SER: -1.07 ± 0.69D) and SVS-SVS group (AL: 0.64 ± 0.29 mm; SER: -1.24 ± 0.63D). No self-reported adverse events, functional or structural damages were noted. CONCLUSIONS: Continued RLRL therapy sustained promising efficacy and safety in slowing myopia progression over 2 years. A modest rebound effect was noted after treatment cessation.

Association between anion gap and mortality of aortic aneurysm in intensive care unit after open surgery.

BACKGROUND: There has not been a well-accepted prognostic model to predict the mortality of aortic aneurysm patients in intensive care unit after open surgery repair. Otherwise, our previous study found that anion gap was a prognosis factor for aortic aneurysm patients. Therefore, we wanted to investigate the relationship between anion gap and mortality of aortic aneurysm patients in intensive care unit after open surgery repair. METHODS: From Medical Information Mart for Intensive Care III, data of aortic aneurysm patients in intensive care unit after open surgery were enrolled. The primary clinical outcome was defined as death in intensive care unit. Univariate analysis was conducted to compare the baseline data in different groups stratified by clinical outcome or by anion gap level. Restricted cubic spline was drawn to find out the association between anion gap level and mortality. Subgroup analysis was then conducted to show the association in different level and was presented as frost plot. Multivariate regression models were built based on anion gap and were adjusted by admission information, severity score, complication, operation and laboratory indicators. Receiver operating characteristic curves were drawn to compare the prognosis ability of anion gap and simplified acute physiology score II. Decision curve analysis was finally conducted to indicate the net benefit of the models. RESULTS: A total of 405 aortic aneurysm patients were enrolled in this study and the in-intensive-care-unit (in-ICU) mortality was 6.9%. Univariate analysis showed that elevated anion gap was associated with high mortality (P value < 0.001), and restricted cubic spline analysis showed the positive correlation between anion gap and mortality. Receiver operating characteristic curve showed that the mortality predictive ability of anion gap approached that of simplified acute physiology score II and even performed better in predicting in-hospital mortality (P value < 0.05). Moreover, models based on anion gap showed that 1 mEq/L increase of anion gap improved up to 42.3% (95% confidence interval 28.5-59.8%) risk of death. CONCLUSIONS: The level of serum anion gap was an important prognosis factor for aortic aneurysm mortality in intensive care unit after open surgery.

Atomic-Scale Structure and Catalysis on Positively Charged Bimetallic Sites for Generation of H2.

Here, we report that a cationic bimetallic site consisting of one Pd and three Zn atoms (Pd1Zn3) supported on ZnO (Pd1Zn3/ZnO) exhibits an extraordinarily high catalytic activity for the generation of H2 through methanol partial oxidation (MPO) that is 2-3 orders of magnitude higher than that of a metallic Pd-Zn site on Pd-Zn nanoalloy (Pd-Zn/ZnO). Computational studies uncovered that the positively charged Pd atom of the subnanometer Pd1Zn3 bimetallic site largely decreases the activation barrier for dehydrogenation of methanol as compared to a metallic Pd atom of Pd-Zn alloy, thus switching the rate-determining step of MPO from methanol dehydrogenation over a Pd-Zn alloy with high barrier to the O2 dissociation step on a cationic Pd1Zn3 site with a low barrier, which is supported by our kinetics studies. The significantly higher catalytic activity and selectivity for H2 production over a cationic bimetallic site suggest a new approach to design bimetallic catalysts.

Synergy of Single-Atom Ni1 and Ru1 Sites on CeO2 for Dry Reforming of CH4.

Heterogeneous catalysis performs on specific sites of a catalyst surface even if specific sites of many catalysts during catalysis could not be identified readily. Design of a catalyst by managing catalytic sites on an atomic scale is significant for tuning catalytic performance and offering high activity and selectivity at a relatively low temperature. Here, we report a synergy effect of two sets of single-atom sites (Ni1 and Ru1) anchored on the surface of a CeO2 nanorod, Ce0.95Ni0.025Ru0.025O2. The surface of this catalyst, Ce0.95Ni0.025Ru0.025O2, consists of two sets of single-atom sites which are highly active for reforming CH4 using CO2 with a turnover rate of producing 73.6 H2 molecules on each site per second at 560 °C. Selectivity for producing H2 at this temperature is 98.5%. The single-atom sites Ni1 and Ru1 anchored on the CeO2 surface of Ce0.95Ni0.025Ru0.025O2 remain singly dispersed and in a cationic state during catalysis up to 600 °C. The two sets of single-atom sites play a synergistic role, evidenced by lower apparent activation barrier and higher turnover rate for production of H2 and CO on Ce0.95Ni0.025Ru0.025O2 in contrast to Ce0.95Ni0.05O2 with only Ni1 single-atom sites and Ce0.95Ru0.05O2 with only Ru1 single-atom sites. Computational studies suggest a molecular mechanism for the observed synergy effects, which originate at (1) the different roles of Ni1 and Ru1 sites in terms of activations of CH4 to form CO on a Ni1 site and dissociation of CO2 to CO on a Ru1 site, respectively and (2) the sequential role in terms of first forming H atoms through activation of CH4 on a Ni1 site and then coupling of H atoms to form H2 on a Ru1 site. These synergistic effects of the two sets of single-atom sites on the same surface demonstrated a new method for designing a catalyst with high activity and selectivity at a relatively low temperature.

Anticancer effect of Limonin against benzo(a)pyrene-induced lung carcinogenesis in Swiss albino mice and the inhibition of A549 cell proliferation through apoptotic pathway.

The main purpose of the current study is to reveal the anticancer action of limonin against benzo(a)pyrene [B(a)P]-treated lung carcinogenesis in Swiss albino mice and A549 lung cancer cells. B(a)P was orally supplemented (50 mg/kg body weight) twice a week for four weeks induction of lung cancer in mice. The lung weight, body weight, incidence of tumor, lipid peroxidation, carcinoembryonic antigen (CEA), enzymatic and nonenzymatic antioxidants (superoxide dismutase, GPx, glutathione, glutathione reductase, catalase, and glutathione S-transferase), serum marker enzymes (aryl hydroxylase, lactate dehydrogenase, 5'-nucleotidases, and γ-glutamyl transpeptidase), and inflammatory mediators (interleukin-1ß, interleukin-6, and tumor necrosis factor-α) were estimated. Moreover, a histopathological study of lung tissues was supported by the biochemical analysis. Furthermore, the anticancer activity of limonin on A549 cells was measured by cell viability, production of reactive oxygen species (ROS), apoptotic morphological changes by AO/EtBr staining. Additionally, the status of apoptosis protein (caspase-9 and -3) expressions was analyzed by the colorimetric analysis. B(a)P-induced mice showed increased lipid peroxidation, CEA, serum marker enzymes and inflammatory cytokines levels with simultaneously decreased in the nonenzymatic and enzymatic antioxidants levels. Limonin supplements significantly reverted back to all these changes in this manner, showing the efficiency of anticancer effect. Furthermore, our in vitro study also supported the anticancer effect of the treatment of limonin-enhanced apoptosis by loss of cell viability, improved ROS production, apoptotic morphological changes, and apoptosis protein expression were analyzed. Overall, these results suggest the anticancer potential of limonin against B(a)P-induced lung cancer in Swiss albino mice and A549 lung cancer cells.

Activation of Methyltrioxorhenium for Olefin Metathesis in a Zirconium-Based Metal-Organic Framework.

The zirconium nodes of the metal-organic framework (MOF) known as NU-1000 serve as competent supports for the activation of methyltrioxorhenium (MTO) toward olefin metathesis. Itself inactive for olefin metathesis, MTO becomes an active catalyst only when immobilized on the strongly acidic Lewis acid sites of dehydrated NU-1000. Uptake of MTO at the dehydrated secondary building units (SBUs) occurs rapidly and quantitatively to produce a catalyst active in both gas- and liquid-phase processes. These results demonstrate for the first time the utility of MOF SBUs for olefin metathesis, an academically and industrially relevant transformation.

Formation of Second-Generation Nanoclusters on Metal Nanoparticles Driven by Reactant Gases.

Heterogeneous catalysis occurs at the interface between a solid catalyst and the reactants. The structure of metal catalyst nanoparticles at the metal-gas interface is a key factor that determines catalytic selectivity and activity. Here we report that second-generation nanoclusters are formed on the initial catalyst nanoparticles as a result of interaction with the reactant molecules when the nanoparticles are in a gas phase at Torr pressure or higher. The formation of the second-generation nanoclusters is manifested by a decrease of the average coordination number of the metal atoms and a shift of their core level energies in the presence of gases. The formation of second-generation nanoclusters increases the number of undercoordinated sites, which are the most active for catalysis in many cases.

Low-Temperature Transformation of Methane to Methanol on Pd1 O4 Single Sites Anchored on the Internal Surface of Microporous Silicate.

Direct conversion of methane to chemical feedstocks such as methanol under mild conditions is a challenging but ideal solution for utilization of methane. Pd1 O4 single-sites anchored on the internal surface of micropores of a microporous silicate exhibit high selectivity and activity in transforming CH4 to CH3 OH at 50-95 °C in aqueous phase through partial oxidation of CH4 with H2 O2 . The selectivity for methanol production remains at 86.4 %, while the activity for methanol production at 95 °C is about 2.78 molecules per Pd1 O4 site per second when 2.0 wt % CuO is used as a co-catalyst with the Pd1 O4 @ZSM-5. Thermodynamic calculations suggest that the reaction toward methanol production is highly favorable compared to formation of a byproduct, methyl peroxide.

Probing the low-temperature water-gas shift activity of alkali-promoted platinum catalysts stabilized on carbon supports.

We report on the direct promotional effect of sodium on the water-gas shift activity of platinum supported on oxygen-free multiwalled carbon nanotubes. Whereas the Na-free Pt catalysts are shown to be completely inactive, the addition of sodium is found to improve the water-gas shift activity to levels comparable to those obtained with highly active Pt catalysts on metal oxide supports. The structure and morphology of the catalyst surface was followed using aberration-corrected HAADF-STEM, which showed that atomically dispersed platinum species are stabilized by the addition of sodium. In situ atmospheric-pressure X-ray photoelectron spectroscopy (AP-XPS) experiments demonstrated that oxidized platinum Pt-OHx contributions in the Pt 4f signal are higher in the presence of sodium, providing evidence for a previously reported active-site structure of the form Pt-Nax-Oy-(OH)z. Pt remained oxidized in all redox experiments, even when a H2-rich gas mixture was used, but the extent of its oxidation followed the oxidation potential of the gas. These findings offer new insights into the nature of the active platinum-based site for the water-gas shift reaction. A strong inhibitory effect of hydrogen was observed on the reaction kinetics, effectively raising the apparent activation energy from 70 ± 5 kJ/mol (in product-free gas) to 105 ± 7 kJ/mol (in full reformate gas). Increased hydrogen uptake was observed on these materials when both Pt and Na were present on the catalyst, suggesting that hydrogen desorption might limit the water-gas shift reaction rate under such conditions.

In-situ studies of nanocatalysis.

A heterogeneous catalyst in industry consists of nanoparticles with variable crystallite sizes, shapes, and compositions. Its catalytic performance (activity, selectivity, and durability) derives from surface chemistry of catalyst nanoparticles during catalysis. However, the surface chemistry of the catalyst particles during catalysis, termed in-situ information, is a "black box" because of the challenges in characterizing the catalysts during catalysis. The lack of such in-situ information about catalysts has limited the understanding of catalytic mechanisms and the development of catalysts with high selectivity and activity. The challenges in understanding heterogeneous catalysis include measurement of reaction kinetics, identification of reaction intermediates, bridging pressure gap and materials gap. The pressure gap is the difference in surface structure and chemistry between a catalyst during catalysis and under an ultrahigh vacuum (UHV) condition. The materials gap represents the difference between the structural and compositional complexity of industrial catalysts and the well-defined surface of model catalysts of metals or oxides. Development of in-situ characterization using electron spectroscopy and electron microscopy in recent decades has made possible studies of surface chemistry and structure of nanocatalysts under reaction conditions or during catalysis at near ambient pressure. In this Account, we review the new chemistries and structures of nanocatalysts during reactions revealed with in-situ analytical techniques. We discuss changes observed during catalysis including the evolution of composition, oxidation state, phase, and geometric structure of the catalyst surface, and the sintering of catalysts. These surface chemistries and structures have allowed researchers to build a correlation between surface chemistry and structure of active nanocatalysts and their corresponding catalytic performances. Such a correlation provides critical insights for understanding catalysis, optimization of existing nanocatalysts, and development of new nanocatalysts with high activity and selectivity.

Conversion of methane to methanol with a bent mono(µ-oxo)dinickel anchored on the internal surfaces of micropores.

The oxidation of methane to methanol is a pathway to utilizing this relatively abundant, inexpensive energy resource. Here we report a new catalyst, bent mono(µ-oxo)dinickel anchored on an internal surface of micropores,which is active for direct oxidation. It is synthesized from the direct loading of a nickel precursor to the internal surface of micropores of ZSM5 following activation in O2. Ni 2p3/2 of this bent mono(µ-oxo)dinickel species formed on the internal surface of ZSM5 exhibits a unique photoemission feature, which distinguishes the mono(µ-oxo)dinickel from NiO nanoparticles. The formation of the mono(µ-oxo)dinickel species was confirmed with X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS). This mono(µ-oxo)dinickel species is active for the direct oxidation of methane to methanol under the mild condition of a temperature as low as 150 °C in CH4 at 1 bar. In-situ studies using UV-vis, XANES, and EXAFS suggest that this bent mono(µ-oxo)dinickel species is the active site for the direct oxidation of methane to methanol. The energy barrier of this direct oxidation of methane is 83.2 kJ/mol.

Restructuring transition metal oxide nanorods for 100% selectivity in reduction of nitric oxide with carbon monoxide.

Transition metal oxide is one of the main categories of heterogeneous catalysts. They exhibit multiple phases and oxidation states. Typically, they are prepared and/or synthesized in solution or by vapor deposition. Here we report that a controlled reaction, in a gaseous environment, after synthesis can restructure the as-synthesized transition metal oxide nanorods into a new catalytic phase. Co3O4 nanorods with a preferentially exposed (110) surface can be restructured into nonstoichiometric CoO1-x nanorods. Structure and surface chemistry during the process were tracked with ambient pressure X-ray photoelectron spectroscopy (AP-XPS) and environmental transmission electron microscopy (E-TEM). The restructured nanorods are highly active in reducing NO with CO, with 100% selectivity for the formation of N2 in temperatures of 250-520 °C. AP-XPS and E-TEM studies revealed the nonstoichiometric CoO1-x nanorods with a rock-salt structure as the active phase responsible for the 100% selectivity. This study suggests a route to generate new oxide catalysts.

Breaking Continuously Packed Bimetallic Sites to Singly Dispersed on Nonmetallic Support for Efficient Hydrogen Production.

We have synthesized Pt1Zn3/ZnO, also termed 0.01 wt %Pt/ZnO-O2-H2, as a catalyst containing singly dispersed single-atom bimetallic sites, also called a catalyst of singly dispersed bimetallic sites or a catalyst of isolated single-atom bimetallic sites. Its catalytic activity in partial oxidation of methanol to hydrogen at 290 °C is found to be 2-3 orders of magnitude higher than that of Pt-Zn bimetallic nanoparticles supported on ZnO, 5.0 wt %Pt/ZnO-N2-H2. Selectivity for H2 on Pt1Zn3/ZnO reaches 96%-100% at 290-330 °C, arising from the uniform coordination environment of single-atom Pt1 in singly dispersed single-atom bimetallic sites, Pt1Zn3 on 0.01 wt %Pt/ZnO-O2-H2, which is sharply different from various coordination environments of Pt atoms in coexisting PtxZny (x ≥ 0, y ≥ 0) sites on Pt-Zn bimetallic nanoparticles. Computational simulations attribute the extraordinary catalytic performance of Pt1Zn3/ZnO to the stronger adsorption of methanol and the lower activation barriers in O-H dissociation of CH3OH, C-H dissociations of CH2O to CO, and coupling of intermediate CO with atomic oxygen to form CO2 on Pt1Zn3/ZnO as compared to those on Pt-Zn bimetallic nanoparticles. It demonstrates that anchoring uniform, isolated single-atom bimetallic sites, also called singly dispersed bimetallic sites on a nonmetallic support can create new catalysts for certain types of reactions with much higher activity and selectivity in contrast to bimetallic nanoparticle catalysts with coexisting, various metallic sites MxAy (x ≥ 0, y ≥ 0). As these single-atom bimetallic sites are cationic and anchored on a nonmetallic support, the catalyst of singly dispersed single-atom bimetallic sites is different from a single-atom alloy nanoparticle catalyst. The critical role of the 0.01 wt %Pt in the extraordinary catalytic performance calls on fundamental studies of the profound role of a trace amount of a metal in heterogeneous catalysis.

Deep neural network-estimated age using optical coherence tomography predicts mortality.

The concept of biological age has emerged as a measurement that reflects physiological and functional decline with ageing. Here we aimed to develop a deep neural network (DNN) model that predicts biological age from optical coherence tomography (OCT). A total of 84,753 high-quality OCT images from 53,159 individuals in the UK Biobank were included, among which 12,631 3D-OCT images from 8,541 participants without any reported medical conditions at baseline were used to develop an age prediction model. For the remaining 44,618 participants, OCT age gap, the difference between the OCT-predicted age and chronological age, was calculated for each participant. Cox regression models assessed the association between OCT age gap and mortality. The DNN model predicted age with a mean absolute error of 3.27 years and showed a strong correlation of 0.85 with chronological age. After a median follow-up of 11.0 years (IQR 10.9-11.1 years), 2,429 deaths (5.44%) were recorded. For each 5-year increase in OCT age gap, there was an 8% increased mortality risk (hazard ratio [HR] = 1.08, CI:1.02-1.13, P = 0.004). Compared with an OCT age gap within ± 4 years, OCT age gap less than minus 4 years was associated with a 16% decreased mortality risk (HR = 0.84, CI: 0.75-0.94, P = 0.002) and OCT age gap more than 4 years showed an 18% increased risk of death incidence (HR = 1.18, CI: 1.02-1.37, P = 0.026). OCT imaging could serve as an ageing biomarker to predict biological age with high accuracy and the OCT age gap, defined as the difference between the OCT-predicted age and chronological age, can be used as a marker of the risk of mortality.