Achieving Active and Stable Amorphous IrVOxOHy for Water Splitting.

Evaluating the structural and electronic-state characteristics of long-range disordered amorphous iridium (Ir)-based oxides is still unsatisfying. Compared with the benchmark IrO2, the higher oxygen evolution reaction (OER) performance brought by IrOxOHy was normally considered to be associated with the pristine IrIII-containing species. However, such a conclusion conflicts with the opinion that high-valence metals can create excellent OER activity. To resolve such contradictions, we synthesized a pure amorphous Lu1.25IrOxOHy (Lu = lutetium) catalyst in this work. In combination with the comprehensive electrochemical evaluation in alkaline and acidic media, ex situ Ir L3-edge and O K-edge X-ray absorption spectroscopy and theoretical calculations revealed that the ultrahigh OER performance of reconstructed IrOx/Lu1.25IrOxOHy in acidic media was identified to be driven by the more d-hole-containing electronic state of IrV created by cationic vacancies. The pristine properties of IrIII-containing Lu1.25IrOxOHy conversely inhibit the OER activity in alkaline media. Additionally, the high edge-shared [IrOx]-[IrOx] motif proportion structure in amorphous Lu1.25IrOxOHy achieves a stable OER process, which exhibits a high S-number stability index similar to IrO2. We demonstrate that the key factor of the edge-shared [IrOx]-[IrOx] motif with cationic vacancies in IrVOxOHy could rationally reveal the source for most of the high-performance Ir-based materials.

Surface Reconstruction for Forming the [IrO6]-[IrO6] Framework: Key Structure for Stable and Activated OER Performance in Acidic Media.

The surface reconstruction of iridium-based derivatives (AxIryOz) was extensively demonstrated to have an excellent oxygen evolution reaction (OER) performance in an acidic medium. It is urgent to use various spectroscopy and computational methods to explore the electronic state changes in the surface reconstruction process. Herein, the underestimated Lu2Ir2O7 was synthesized and investigated. Four typical forms of electrochemistry impedance spectra involved in the reconstruction process revealed three dominating forms of reconstructed pyrochlore in the OER stage, including the inner intact pyrochlore, mid metastable [IrO6]-[IrO6] framework, and the outer collapse amorphous layer. The enhancing electron transport efficiency of the corner-shared [IrO6]-[IrO6] framework was revealed as a critical role in acidic systems. The density of state (DOS) for the constructed [IrO6]-[IrO6] framework corroborated the enhancement of Ir-O hybridization and the downshift of the d-band center. Additionally, we contrast the pristine and reconstruction properties of the Pr2Ir2O7, Eu2Ir2O7, and Lu2Ir2O7 in alkaline and acidic media. The DOS and the XANES results reveal the scale relationship between the O 2p band center and the intrinsic activity for bulk pyrochlore in alkaline media. The highest O 2p center and the highest Ir-O hybridization of Lu2Ir2O7 exhibited the best OER performance among the Ir-based pyrochlore, up to a ninefold improvement in Ir-mass activity compared to IrO2. Our findings emphasize the electrochemical behavior of the reconstruction process for activated water-splitting performance.

Computerized Symbol Digit Modalities Test in a Swiss Pediatric Cohort - Part 2: Clinical Implementation.

BACKGROUND: Information processing speed (IPS) is a marker for cognitive function. It is associated with neural maturation and increases during development. Traditionally, IPS is measured using paper and pencil tasks requiring fine motor skills. Such skills are often impaired in patients with neurological conditions. Therefore, an alternative that does not need motor dexterity is desirable. One option is the computerized symbol digit modalities test (c-SDMT), which requires the patient to verbally associate numbers with symbols. METHODS: Eighty-six participants (8-16 years old; 45 male; 48 inpatients) were examined, 38 healthy and 48 hospitalized for a non-neurological disease. All participants performed the written SDMT, c-SDMT, and the Test of Non-verbal Intelligence Fourth Edition (TONI-4). Statistical analyses included a multivariate analysis of covariance (MANCOVA) for the effects of intelligence (IQ) and hospitalization on the performance of the SDMT and c-SDMT. A repeated measures analysis of variance (repeated measures ANOVA) was used to compare performance across c-SDMT trials between inpatients and outpatients. RESULTS: The MANCOVA showed that hospitalization had a significant effect on IPS when measured with the SDMT (p = 0.04) but not with the c-SDMT (p = 0.68), while IQ (p = 0.92) had no effect on IPS. Age (p < 0.001) was the best predictor of performance of both tests. The repeated measures ANOVA revealed no significant difference in within-test performance (p = 0.06) between outpatient and inpatient participants in the c-SDMT. CONCLUSION: Performance of the c-SDMT is not confounded by hospitalization and gives within-test information. As a valid and reliable measure of IPS for children and adolescents, it is suitable for use in both inpatient and outpatient populations.

Computerized Symbol Digit Modalities Test in a Swiss Pediatric Cohort Part 1: Validation.

OBJECTIVE: The objective of this study was to validate the computerized Symbol Digit Modalities Test (c-SDMT) in a Swiss pediatric cohort, in comparing the Swiss sample to the Canadian norms. Secondly, we evaluated sex effects, age-effects, and test-retest reliability of the c-SDMT in comparison to values obtained for the paper and pencil version of the Symbol Digit Modalities Test (SDMT). METHODS: This longitudinal observational study was conducted in a single-center setting at the University Children's Hospital of Bern. Our cohort consisted of 86 children (45 male and 41 female) aged from 8 to 16 years. The cohort included both healthy participants (n = 38) and patients (n = 48) hospitalized for a non-neurological disease. Forty eight participants were assessed during two testing sessions with the SDMT and the c-SDMT. RESULTS: Test-retest reliability was high in both tests (SDMT: ICC = 0.89, c-SDMT: ICC = 0.90). A reliable change index was calculated for the SDMT (RCIp = -3.18, 14.01) and the c-SDMT (RCIp = -5.45, 1.46) corrected for practice effects. While a significant age effect on information processing speed was observed, no such effect was found for sex. When data on the c-SDMT performance of the Swiss cohort was compared with that from a Canadian cohort, no significant difference was found for the mean time per trial in any age group. Norm values for age groups between 8 and 16 years in the Swiss cohort were established. CONCLUSION: Norms for the c-SDMT between the Swiss and the Canadian cohort were comparable. The c-SDMT is a valid alternative to the SDMT. It is a feasible and easy to administer bedside tool due to high reliability and the lack of motor demands.

A promising engineering strategy for water electro-oxidation iridate catalysts via coordination distortion.

Here, we study the relationship between the coordination structure of IrO6 and OER activity in a wide range of oxides with systematic comparisons. The results reveal that distorted IrO6 is more conducive to OER activity. Specifically, for a given material, regulating the transformation of the IrO6 octahedron from D4h compression to D4h elongation causes electrons near the EF level to become more delocalized, which is very beneficial for reducing the energy of the rate determining step. Our findings will guide the design and preparation of more efficient iridium-based OER catalysts.

Treadmill training improves neurological deficits and suppresses neuronal apoptosis in cerebral ischemic stroke rats.

Rehabilitation training is believed to be beneficial to patients with stroke, but its molecular mechanism is still unclear. Rat models of cerebral ischemic stroke were established by middle cerebral artery occlusion/reperfusion, and then received treadmill training of different intensities, twice a day for 30 minutes for 1 week. Low-intensity training was conducted at 5 m/min, with a 10-minute running, 10-minute rest, and 10-minute running cycle. In the moderate-intensity training, the intensity gradually increased from 5 m/min to 10 m/min in 5 minutes, with the same rest cycle as above. In high-intensity training, the intensity gradually increased from 5 m/min to 25 m/min in 5 minutes, with the same rest cycle as above. The Bederson scale was used to evaluate the improvement of motor function. Infarct volume was detected using 2,3,5-triphenyltetrazolium chloride staining. Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling staining was applied to detect the apoptosis of nerve cells in brain tissue. Western blot assay was employed to analyze the activation of cyclic adenosine monophosphate (cAMP)/protein kinase A and Akt/glycogen synthase kinase-3ß signaling pathways in rat brain tissue. All training intensities reduced the neurological deficit score, infarct volume, and apoptosis in nerve cells in brain tissue of stroke rats. Training intensities activated the cAMP/protein kinase A and Akt/glycogen synthase kinase-3 beta signaling pathways. This activation was more obvious with higher training intensities. These changes were reversed by intracerebroventricular injection of protein kinase A inhibitor Rp-cAMP. Our findings indicate that the neuroprotective effect of rehabilitation training is achieved via activation of the cAMP/protein kinase A and Akt/glycogen synthase kinase-3 beta signaling pathways. This study was approved by the Ethics Committee of Animal Experimentation in Shanghai No. 8 People's Hospital, China.

Cultivating crystal lattice distortion in IrO2via coupling with MnO2 to boost the oxygen evolution reaction with high intrinsic activity.

Here, we report an effective strategy to lower Ir consumption and boost the OER performance in acid by loading IrO2 onto MnO2, in which the IrO2 crystals are well dispersed and undergo a so-called z-extension Jahn-Teller distortion in the octahedral structure. Compared with IrO2, the mass activity and intrinsic activity for IrO2/MnO2 were largely increased.

Rational Manipulation of IrO2 Lattice Strain on α-MnO2 Nanorods as a Highly Efficient Water-Splitting Catalyst.

Developing more efficient and stable oxygen evolution reaction (OER) catalysts is critical for future energy conversion and storage technologies. We demonstrate that inducing a lattice strain in IrO2 crystal structure due to interface lattice mismatch enables an enhancement of the OER catalytic activity. The lattice strain is obtained by the direct growth of IrO2 nanoparticles on a specially exposed surface of α-MnO2 nanorods via a simple two-step hydrothermal synthesis. Interestingly, the prepared hydride OER activity increases with a lower IrO2 grown mass, which offers an opportunity to reduce the usage of precious iridium and ultimately obtains a specific mass activity of 3.7 times than that of IrO2 prepared under the same conditions and exhibits equivalent stability. The lattice mismatch in the underlying interface induces the formation of lattice strain in IrO2 rather than the charge transfer between the materials. The lattice strain changes are in good agreement with the order of the OER activity. Our experimental results indicate that using the special exposed surface substrates or tuning the supporting morphology structure can manipulate the catalyst materials lattice strain for the design of more efficient OER catalysts.

OER activity manipulated by IrO6 coordination geometry: an insight from pyrochlore iridates.

The anodic reaction of oxygen evolution reaction (OER), an important point for electrolysis, however, remains the obstacle due to its complicated reaction at electrochemical interfaces. Iridium oxide (IrO2) is the only currently known 5d transition metal oxide possessing admirable OER activity. Tremendous efforts have been carried out to enhance the activity of iridium oxides. Unfortunately there lies a gap in understanding what factors responsible for the activity in doped IrO2 or the novel crystal structure. Based on two metallic pyrochlores (Bi2Ir2O7 and Pb2Ir2O6.5) and IrO2. It has been found that there exists a strong correlation between the specific OER activity and IrO6 coordination geometry. The more distortion in IrO6 geometry ascends the activity of Ir sites, and generates activity order of Pb-Ir > IrO2 > Bi-Ir. Our characterizations reveal that distorted IrO6 in Pb-Ir induces a disappearance of J = 1/2 subbands in valence band, while Bi-Ir and IrO2 resist this nature probe. The performed DFT calculations indicated the distortion in IrO6 geometry can optimize binding strength between Ir-5d and O-2p due to broader d band width. Based on this insight, enhancement in OER activity is obtained by effects that change IrO6 octahedral geometry through doping or utilizing structural manipulation with nature of distorted octahedral coordination.

Pt-Doped NiFe2O4 Spinel as a Highly Efficient Catalyst for H2 Selective Catalytic Reduction of NO at Room Temperature.

H2 selective catalytic reduction (H2-SCR) has been proposed as a promising technology for controlling NOx emission because hydrogen is clean and does not emit greenhouse gases. We demonstrate that Pt doped into a nickel ferrite spinel structure can afford a high catalytic activity of H2-SCR. A superior NO conversion of 96% can be achieved by employing a novel NiFe1.95Pt0.05O4 spinel-type catalyst at 60 °C. This novel catalyst is different from traditional H2-SCR catalysts, which focus on the role of metallic Pt species and neglect the effect of oxidized Pt states in the reduction of NO. The obtained Raman and XPS spectra indicate that Pt in the spinel lattice has different valence states with Pt(2+) occupying the tetrahedral sites and Pt(4+) residing in the octahedral ones. These oxidation states of Pt enhance the back-donation process, and the lack of filling electrons of the 5d band causes Pt to more readily hybridize with the 5σ orbital of the NO molecule, especially for octahedral Pt(4+), which enhances the NO chemisorption on the Pt sites. We also performed DFT calculations to confirm the enhancement of adsorption of NO onto Pt sites when doped into the Ni-Fe spinel structure. The prepared Pt/Ni-Fe catalysts indicate that increasing the dispersity of Pt on the surfaces of the individual Ni-Fe spinel-type catalysts can efficiently promote the H2-SCR activity. Our demonstration provides new insight into designing advanced catalysts for H2-SCR.

Hollandite Structure K(x≈0.25)IrO2 Catalyst with Highly Efficient Oxygen Evolution Reaction.

Oxygen evolution reaction (OER) catalysts with high activity are of particular importance for renewable energy production and storage. Here, we prepare Kx≈0.25IrO2 catalyst that exhibits an excellent OER activity compared to IrO2, which is univerally acknoweledged as a state-of-the-art OER catalyst. The prepared catalyst reflects a small overpotential 0.35 V at a current density of 10 mA cm(-2) and a lower Tafel slope (65 mV dec(-1)) compared to that for IrO2 (74 mV dec(-1)). The performed X-ray photoelectron spectroscopy (XPS) and X-ray adsorption (XAS) experiments indicate that the Ir-site of Kx≈0.25IrO2 has a lower valence and more Ir-5d occupied states, suggesting more electrons on the Ir site. The extra electrons located on the Ir site and distorted IrO6 octahedral symmetry have a significant effect on the 5d orbital energy distribution which is verified by our DOS calculation. The performed DFT calculations state that the Kx≈0.25IrO2 essentially obtains good OER performance because it has a lower theoretical overpotential (0.50 V) compared to IrO2 (0.61 V).

Role of ((E)-(E)-4-(4-hydroxy-3-methoxyphenyl)-2-oxobut-3-en-1-yl 3-(4-hydroxy-3-methoxyphenyl) acrylate in preservation of spatial cognitive functions of rats with chronic epilepsy.

The present study demonstrates the effect of ((E)-(E)-4-(4-hydroxy-3-methoxyphenyl)-2-oxobut-3-en-1-yl 3-(4-hydroxy-3-methoxyphenyl) acrylate (CA) on spatial cognitive functions of rats with lobal cerebrovascular hypoperfusion. The bilateral common carotid arteries occlusion (2VO) surgery was performed to prepare the cerebrovascular hypoperfusion rat model. The effect of CA on spatial cognitive function was analysed using Morris water maze (MWM) test prior to and after 2VO operation. Sixty rats were randomly assigned into two groups of 30 each; long-term memory (LTM) and short-term memory (STM) groups. Both the groups were further divided into 3 subgroups: control, untreated and CA treated groups. The animals received 50 µg/kg of CA for 10 weeks of 2VO operation following which all the subgroups were tested with MWM. Both the escape latency time and total distance travelled were significantly lower for control and CA treated groups compared to untreated group revealed by working memory test. The maze test performance for control and CA treated groups was found to be improved markedly. Similarly, the results from probe memory test performance revealed significant improvement for CA treated groups compared to untreated group. Therefore, CA exhibits significant effect on the spatial cognitive preservation in rats with chronic epilepsy.

An efficiently tuned d-orbital occupation of IrO2 by doping with Cu for enhancing the oxygen evolution reaction activity.

The oxygen evolution reaction (OER) has been regarded as a key half reaction for energy conversion technologies and requires high energy to create O[double bond, length as m-dash]O bonds. Transition metal oxides (TMOs) seem to be a promising and appealing solution to the challenge because of the diversity of their d-orbital states. We chose IrO2 as a model because it is universally accepted as a current state-of-the-art OER catalyst. In this study, copper-doped IrO2, particularly Cu0.3Ir0.7O δ , is shown to significantly improve the OER activity in acidic, neutral and basic solutions compared to un-doped IrO2. The substituted amount of Cu in IrO2 has a limit described by the Cu0.3Ir0.7O δ composition. We determined that the performance of Cu0.3Ir0.7O δ is due primarily to an increase in the Jahn-Teller effect in the CuO6 octahedra, and partially to oxygen defects in the lattice induced by the IrO6 octahedral geometric structure distortions, which enhance the lift degeneracy of the t2g and eg orbitals, making the d z 2 orbital partially occupied. This phenomenon efficiently reduces the difference between ΔG2 and ΔG3 in the free energy from the density functional theoretical (DFT) calculations and can yield a lower theoretical overpotential comparable to that of IrO2. The proposed method of doping with foreign elements to tune the electron occupation between the t2g and eg orbital states of Ir creates an opportunity for designing effective OER catalysts using the TMO groups.

Endoplasmic Reticulum Protein 29 Protects Axotomized Neurons from Apoptosis and Promotes Neuronal Regeneration Associated with Erk Signal.

Spinal cord injury (SCI) results in a series of severe dysfunction of sensory and motor functions, while the molecular mechanisms that cause these dysfunctions remain elusive. Using proteomics technology, Western blot (WB), and immunohistochemistry (IHC), we found endoplasmic reticulum protein 29 (ERp29) was substantially downregulated in the motor cortex 3 days postoperation (dpo) after spinal cord transection (SCT, T10) followed by a gradual recovery 28 dpo. IHC showed that ERp29 is expressed in cortical neurons. In order to investigate the role of ERp29 in axotomized cortical neurons, we developed an in vitro axotomy injury model. ERp29 overexpression in cortical neurons after axotomy protected them from apoptosis; prevented the reduction of the number of neurons, and prevented reduction of neurite length. Moreover, we found that ERp29 overexpression increased neuronal regeneration assessed by neurite number and length. Furthermore, overexpression of ERp29 in cortical neurons after axotomy increased expression of Erk-1 and PI3K while decreasing the expression of caspase-3 expression. The present data therefore provides evidence to address the role of ERp29 in axotomized cortical neurons and identifies new therapeutic targets for the treatment of SCI.

Electro-thermal treatment optimization of high concentration ammonia nitrogen by gaseous oxidation in liquid phase (GOLP).

This study is focused on optimizing the treatment parameters for high concentration ammonia using gaseous oxidation in liquid phase (GOLP). The conversion of ammonia was achieved electrothermally over mono-crystalline silicon supported CoOx catalyst. The experimental results demonstrated that factors including the co-anions, pH of the solutions, air flowrate and the current showed apparent influences on the ammonia removal. The higher the Cl(-) concentration and/or current, the better the efficiency of ammonia degradation. The increase of the air flowrate would increase the ammonia removal accordingly. And it was also observed that the pH declined during the ammonia conversion, and the neutral and alkaline pH were beneficial to the ammonia removal. The preliminary cost analysis based on lab data was also provided for future reference.