Electronic Structure Regulation by Fe Doped Ni-Phosphides for Long-term Overall Water Splitting at Large Current Density.

Acquiring a highly efficient electrocatalyst capable of sustaining prolonged operation under high current density is of paramount importance for the process of electrocatalytic water splitting. Herein, Fe-doped phosphide (Fe-Ni5P4) derived from the NiFc metal-organic framework (NiFc-MOF) (Fc: 1,1'-ferrocene dicarboxylate) shows high catalytic activity for overall water splitting (OWS). Fe-Ni5P4||Fe-Ni5P4 exhibits a low voltage of 1.72 V for OWS at 0.5 A cm-2 and permits stable operation for 2700 h in 1.0 m KOH. Remarkably, Fe-Ni5P4||Fe-Ni5P4 can sustain robust water splitting at an extra-large current density of 1 A cm-2 for 1170 h even in alkaline seawater. Theoretical calculations confirm that Fe doping simultaneously reduces the reaction barriers of coupling and desorption (O*→OOH*, OOH*→O2 *) in the oxygen evolution reaction (OER) and regulates the adsorption strength of the intermediates (H2O*, H*) in the hydrogen evolution reaction (HER), enabling Fe-Ni5P4 to possess excellent dual functional activity. This study offers a valuable reference for the advancement of highly durable electrocatalysts through the regulation derived from coordination frameworks, with significant implications for industrial applications and energy conversion technologies.

Association between Blood Urea Nitrogen Level and In-Hospital Mortality in Patients with Acute Myocardial Infarction and Subsequent Gastrointestinal Bleeding.

Background: Limited studies have explored the association between blood urea nitrogen (BUN) levels and in-hospital mortality in patients with acute myocardial infarction (AMI) and subsequent gastrointestinal bleeding (GIB). Our objective was to explore this correlation. Methods: 276 individuals with AMI and subsequent GIB were retrospectively included between January 2012 and April 2023. The predictive value of BUN for in-hospital mortality was assessed through receiver operating characteristic (ROC) curve. Logistic regression models were constructed to assess the relationship between BUN and in-hospital mortality. Propensity score weighting (PSW), sensitivity and subgroup analyses were used to further explore the association. Results: Fifty-three (19.2%) patients died in the hospital. BUN levels were higher in non-survivors compared with the survivors [(11.17 ± 6.17) vs (8.09 ± 4.24), p = 0.001]. The ROC curve suggested that the optimal cut-off for BUN levels to predict in-hospital mortality was 8.45 mmol/L (AUC [area under the ROC curve] 0.678, 95% confidence interval [CI] 0.595-0.761, p < 0.001). Multivariable logistic regression showed that elevated BUN levels ( ≥ 8.45 mmol/L) were positively association with in-hospital mortality (odds ratio [OR] 4.01, 95% CI 1.55-10.42, p = 0.004). After PSW, sensitivity and subgroup analyses, the association remained significant. Conclusions: Elevated BUN levels were associated with in-hospital mortality in patients with AMI and subsequent GIB.

Ir Nanoparticles Anchored on Metal-Organic Frameworks for Efficient Overall Water Splitting under pH-Universal Conditions.

The construction of high-activity and low-cost electrocatalysts is critical for efficient hydrogen production by water electrolysis. Herein, we developed an advanced electrocatalyst by anchoring well-dispersed Ir nanoparticles on nickel metal-organic framework (MOF) Ni-NDC (NDC: 2,6-naphthalenedicarboxylic) nanosheets. Benefiting from the strong synergy between Ir and MOF through interfacial Ni-O-Ir bonds, the synthesized Ir@Ni-NDC showed exceptional electrocatalytic performance for hydrogen evolution reaction (HER), oxygen evolution reaction (OER) and overall water splitting in a wide pH range, superior to commercial benchmarks and most reported electrocatalysts. Theoretical calculations revealed that the charge redistribution of Ni-O-Ir bridge induced the optimization of H2 O, OH* and H* adsorption, thus leading to the accelerated electrochemical kinetics for HER and OER. This work provides a new clue to exploit bifunctional electrocatalysts for pH-universal overall water splitting.

Redox-Active Mixed-Linker Metal-Organic Frameworks with Switchable Semiconductive Characteristics for Tailorable Chemiresistive Sensing.

Metal-organic frameworks (MOFs), with diverse metal nodes and designable organic linkers, offer unique opportunities for the rational engineering of semiconducting properties. In this work, we report a mixed-linker conductive MOF system with both tetrathiafulvalene and Ni-bis(dithiolene) moieties, which allows the fine-tuning of electronic structures and semiconductive characteristics. By continuously increasing the molar ratio between tetrathiafulvalene and Ni-bis(dithiolene), the switching of the semiconducting behaviors from n-type to p-type was observed along with an increase in electrical conductivity by 3 orders of magnitude (from 2.88×10-7  S m-1 to 9.26×10-5  S m-1 ). Furthermore, mixed-linker MOFs were applied for the chemiresistive detection of volatile organic compounds (VOCs), where the sensing performance was modulated by the corresponding linker ratios, showing synergistic and nonlinear modulation effects.

Electrocatalytic Synthesis of Essential Amino Acids from Nitric Oxide Using Atomically Dispersed Fe on N-doped Carbon.

How to transfer industrial exhaust gases of nitrogen oxides into high-values product is significantly important and challenging. Herein, we demonstrate an innovative method for artificial synthesis of essential α-amino acids from nitric oxide (NO) by reacting with α-keto acids through electrocatalytic process with atomically dispersed Fe supported on N-doped carbon matrix (AD-Fe/NC) as the catalyst. A yield of valine with 32.1 µmol mgcat -1 is delivered at -0.6 V vs. reversible hydrogen electrode, corresponding a selectivity of 11.3 %. In situ X-ray absorption fine structure and synchrotron radiation infrared spectroscopy analyses show that NO as nitrogen source converted to hydroxylamine that promptly nucleophilic attacked on the electrophilic carbon center of α-keto acid to form oxime and subsequent reductive hydrogenation occurred on the way to amino acid. Over 6 kinds of α-amino acids have been successfully synthesized and gaseous nitrogen source can be also replaced by liquid nitrogen source (NO3 - ). Our findings not only provide a creative method for converting nitrogen oxides into high-valued products, which is of epoch-making significance towards artificial synthesis of amino acids, but also benefit in deploying near-zero-emission technologies for global environmental and economic development.

On-Chip Investigation of Electrocatalytic Oxygen Reduction Reaction of 2D Materials.

The on-chip electrocatalytic microdevice (OCEM) is an emerging platform specialized in the electrochemical investigation of single-entity nanomaterials, which is ideal for probing the intrinsic catalytic properties, optimizing performance, and exploring exotic mechanisms. However, the current catalytic applications of OCEMs are almost exclusively in electrocatalytic hydrogen/oxygen evolution reactions with minimized influence from the mass transfer. Here, an OCEM platform specially tailored to investigate the electrocatalytic oxygen reduction reaction (ORR) at a microscopic level by introducing electrolyte convection through a microfluidic flow cell is reported. The setup is established on gold microelectrodes and later successfully applied to investigate how Ar-plasma treatment affects the ORR activities of 2H MoS2 . This study finds that Ar-plasma treatment significantly enhances the ORR performance of MoS2 nanosheets owing to the introduction of surface defects. This study paves the way for highly efficient microscopic investigation of diffusion-controlled electrocatalytic reactions.

Tailoring the Electronic Structure of an Atomically Dispersed Zinc Electrocatalyst: Coordination Environment Regulation for High Selectivity Oxygen Reduction.

Accurately regulating the selectivity of the oxygen reduction reaction (ORR) is crucial to renewable energy storage and utilization, but challenging. A flexible alteration of ORR pathways on atomically dispersed Zn sites towards high selectivity ORR can be achieved by tailoring the coordination environment of the catalytic centers. The atomically dispersed Zn catalysts with unique O- and C-coordination structure (ZnO3 C) or N-coordination structure (ZnN4 ) can be prepared by varying the functional groups of corresponding MOF precursors. The coordination environment of as-prepared atomically dispersed Zn catalysts was confirmed by X-ray absorption fine structure (XAFs). Notably, the ZnN4 catalyst processes a 4 e- ORR pathway to generate H2 O. However, controllably tailoring the coordination environment of atomically dispersed Zn sites, ZnO3 C catalyst processes a 2 e- ORR pathway to generate H2 O2 with a near zero overpotential and high selectivity in 0.1 M KOH. Calculations reveal that decreased electron density around Zn in ZnO3 C lowers the d-band center of Zn, thus changing the intermediate adsorption and contributing to the high selectivity towards 2 e- ORR.

Investigation on Distribution and Risk Assessment of Volatile Organic Compounds in Surface Water, Sediment, and Soil in a Chemical Industrial Park and Adjacent Area.

The occurrences, distributions, and risks of 55 target volatile organic compounds (VOCs) in water, sediment, sludge, and soil samples taken from a chemical industrial park and the adjacent area were investigated in this study. The Σ55-VOCs concentrations in the water, sediment, sludge, and soil samples were 1.22-5449.21 µg L-1, ND-52.20 ng g-1, 21.53 ng g-1, and ND-11.58 ng g-1, respectively. The main products in this park are medicines, pesticides, and novel materials. As for the species of VOCs, aromatic hydrocarbons were the dominant VOCs in the soil samples, whereas halogenated aliphatic hydrocarbons were the dominant VOCs in the water samples. The VOCs concentrations in water samples collected at different locations varied by 1-3 orders of magnitude, and the average concentration in river water inside the park was obviously higher than that in river water outside the park. However, the risk quotients for most of the VOCs indicated a low risk to the relevant, sensitive aquatic organisms in the river water. The average VOCs concentration in soil from the park was slightly higher than that from the adjacent area. This result showed that the chemical industrial park had a limited impact on the surrounding soil, while the use of pesticides, incomplete combustion of coal and biomass, and automobile exhaust emissions are all potential sources of the VOCs in the environmental soil. The results of this study could be used to evaluate the effects of VOCs emitted from chemical production and transportation in the park on the surrounding environment.

Double-Exchange-Induced in situ Conductivity in Nickel-Based Oxyhydroxides: An Effective Descriptor for Electrocatalytic Oxygen Evolution.

Motivated by in silico predictions that Co, Rh, and Ir dopants would lead to low overpotentials to improve OER activity of Ni-based hydroxides, we report here an experimental confirmation on the altered OER activities for a series of metals (Mo, W, Fe, Ru, Co, Rh, Ir) doped into γ-NiOOH. The in situ electrical conductivity for metal doped γ-NiOOH correlates well with the trend in enhanced OER activities. Density functional theory (DFT) calculations were used to rationalize the in situ conductivity of the key intermediate states of metal doped γ-NiOOH during OER. The simultaneous increase of OER activity with intermediate conductivity was later rationalized by their intrinsic connections to the double exchange (DE) interaction between adjacent metal ions with various d orbital occupancies, serving as an indicator for the key metal-oxo radical character, and an effective descriptor for the mechanistic evaluation and theoretical guidance in design and screening of efficient OER catalysts.

Dissecting the Role of DDX21 in Regulating Human Cytomegalovirus Replication.

DDX21 regulates the biogenesis of rRNA and transcription of ribonucleoprotein genes. Recently, it has been reported that DDX21 regulates the growth of some RNA viruses through various mechanisms, such as inhibiting viral genome replication, suppressing virion assembly and release, and modulating antiviral immune responses (Chen et al., Cell Host Microbe 15:484-493, 2014, https://doi.org/10.1016/j.chom.2014.03.002; Dong et al., Biophys Res Commun, 473:648-653, 2016, https://doi.org/10.1016/j.bbrc.2016.03.120; and Watanabe et al., PLoS Pathog 5:e1000654, 2009, https://doi.org/10.1371/journal.ppat.1000654). The relationship between DDX21 and DNA viruses has not yet been explored. In this study, we used human cytomegalovirus (HCMV), a large human DNA virus, to investigate the potential role of DDX21 in DNA virus replication. We found that HCMV infection prevented the repression of DDX21 at protein and mRNA levels. Knockdown of DDX21 inhibited HCMV growth in human fibroblast cells (MRC5). Immunofluorescence and quantitative PCR (qPCR) results showed that knockdown of DDX21 did not affect viral DNA replication or the formation of the viral replication compartment but did significantly inhibit viral late gene transcription. Some studies have reported that DDX21 knockdown promotes the accumulation of R-loops that could restrain RNA polymerase II elongation and inhibit the transcription of certain genes. Thus, we used the DNA-RNA hybrid-specific S9.6 antibody to stain R-loops and observed that more R-loops formed in DDX21-knockdown cells than in control cells. Moreover, an DNA-RNA immunoprecipitation assay showed that more R-loops accumulated on a viral late gene in DDX21-knockdown cells. Altogether, these results suggest that DDX21 knockdown promotes the accumulation of R-loops, which prevents viral late gene transcription and consequently results in the suppression of HCMV growth. This finding provides new insight into the relationship between DDX21 and DNA virus replication.IMPORTANCE Previous studies have confirmed that DDX21 is vital for the regulation of various aspects of RNA virus replication. Our research is the first report on the role of DDX21 in HCMV DNA virus replication. We identified that DDX21 knockdown affected HCMV growth and viral late gene transcription. In order to elucidate how DDX21 regulated this transcription, we applied DNA-RNA immunoprecipitation by using the DNA-RNA hybrid-specific S9.6 antibody to test whether more R-loops accumulated on the viral late gene. Consistent with our expectation, more R-loops were detected on the viral late gene at late HCMV infection time points, which demonstrated that the accumulation of R-loops caused by DDX21 knockdown prevented viral late gene transcription and consequently impaired HCMV replication. These results reveal that DDX21 plays an important role in regulating HCMV replication and also provide a basis for investigating the role of DDX21 in regulating other DNA viruses.