Dynamic Electric Field Alignment Determines the Water Rotational Motion around Protein

Water rotational dynamics in biomolecular solution is crucial to evaluating and controlling biomolecule stability. In this molecular dynamics simulation (MD) study on lysozyme solutions, we present how the exerted internal electric field determines water rotational dynamics. We find that the relaxation time of water rotation is equivalent to that of the reorientation of the exerted overall electric field for every single water molecule, regardless of its translation mode. Namely, water molecular rotation synchronizes with the exerted field reorientation. We also map the reorientation process of the electric field at fixed points relative to protein in the solution, which displays the local hydration dynamics commensurate with the reported time-dependent fluorescence Stokes shift (TDFSS) measurements. Comparing the spatial distribution of local field reorientation relaxation time with that of rotational relaxation time, we further suggest that water rotation dynamics are subject to the reorientation of the local overall field within the hydration layer. While outside the hydration layer, the relaxation time of the local electric field reorientation is short enough (subpicosecond) to assume the δ function, showing the electric force with randomly changing orientation is applied to each water molecule

Effects of Chlorine Addition on Nitrogen Oxide Reduction and Mercury Oxidation over Selective Catalytic Reduction Catalysts

The effect of chlorine on mercury oxidation and nitrogen oxides (NOx) reduction over selective catalytic reduction (SCR) catalysts was investigated in this study. Commercial SCR catalysts achieved a high Hg0 oxidation efficiency when Cl2 was sprayed into the flue gas. Results indicated that an appropriate concentration of Cl2 was found to promote NOx reduction and Hg0 oxidation significantly. An optimal concentration of Cl2 (25 ppm) was found to significantly promote NOx reduction and Hg0 oxidation. Moreover, we studied the effects of Cl2 on NOx reduction and Hg0 oxidation over SCR catalysts under different concentrations of SO2. The SO2 poisoning effect was decreased by Cl2 when the SO2 concentration was low (below 1500 ppm). However, sulfate gradually covered the catalyst surface over time during the reaction, which limited the impact of Cl2. Finally, different sulfur-poisoned catalysts were examined in the presence of Cl2. The NOx reduction and Hg0 oxidation performances of sulfate-poisoned catalysts improved when Cl2 was added to the flue gas. Mechanisms for NOx reduction and Hg0 oxidation over fresh catalysts and sulfate-poisoned catalysts in the presence of Cl2 were proposed in this study. The mechanism of Cl2-influenced NOx reduction was similar to that for the NH3-SCR process. With Cl2 in the flue gas, the number of Brønsted active sites increased, which improved catalytic activity. Furthermore, Cl2 reoxidized V4+–OH to V5+O and caused the NH3-SCR process to operate continuously. The Langmuir–Hinshelwood mechanism was followed for Hg0 oxidation by SCR catalysts when Cl2 was in the flue gas. Cl2 increased the number of Lewis active sites, and catalytic activity increased. Hg0 adsorbed on the surface of the catalysts and was then oxidized to HgCl2. Adding Cl2 to the flue gas increased the strength and number of acid sites on sulfate-poisoned catalysts

Stochastic Analysis of Molecular Dynamics Reveals the Rotation Dynamics Distribution of Water around Lysozyme

Water dynamics is essential to biochemical processes by mediating all such reactions, including biomolecular degeneration in solutions. To disentangle the molecular-scale distribution of water dynamics around a solute biomolecule, we investigated here the rotational dynamics of water around lysozyme by combining molecular dynamics (MD) simulations and broadband dielectric spectroscopy (BDS). A statistical analysis using the relaxation times and trajectories of every single water molecule was proposed, and the two-dimensional probability distribution of water at a distance from the lysozyme surface with a rotational relaxation time was given. For the observed lysozyme solutions of 34–284 mg/mL, we discovered that the dielectric relaxation time obtained from this distribution agrees well with the measured γ relaxation time, which suggests that rotational self-correlation of water molecules underlies the gigahertz domain of the dielectric spectra. Regardless of protein concentration, water rotational relaxation time versus the distance from the lysozyme surface revealed that the water rotation is severely retarded within 3 Å from the lysozyme surface and is nearly comparable to pure water when farther than 10 Å. The dimension of the first hydration layer was subsequently identified in terms of the relationship between the acceleration of water rotation and the distance from the protein surface

Ar Plasma-Exfoliated Ultrathin NiCo-Layered Double Hydroxide Nanosheets for Enhanced Oxygen Evolution

Layered double hydroxide (LDH)-based materials are frequently used for oxygen evolution reactions (OERs) due to their promising properties in overcoming the large energy barrier. In this work, the controllably synthesized NiCo-LDHs nanosheets are treated by Ar plasma and display superior activity as well as high durability for OER processes, where there is a much lower overpotential of 299 mV at 10 mA cm–2 and a smaller Tafel slope of 45 mV dec–1 as compared to the pristine material (347 mV and 149 mV dec–1, respectively). The characterization results reveal that numerous defects induced by Ar plasma on the surface of ultrathin NiCo-LDHs nanosheets, leading to many more exposed active sites, faster kinetics, and lower resistance. This work offers inspiration for the rational design of additional active and efficient LDH-based materials for OER

Additional file 4 of Hypoxia-mediated YTHDF2 overexpression promotes lung squamous cell carcinoma progression by activation of the mTOR/AKT axis

Additional file 4. The clinicopathological characteristics of LUSC

Additional file 1 of Hypoxia-mediated YTHDF2 overexpression promotes lung squamous cell carcinoma progression by activation of the mTOR/AKT axis

Additional file 1: Figure S1. Immunohistochemical staining of LUSC tissue sections demonstrating YTHDF2. (A) The corresponding normal lung tissue specimen with low expression of YTHDF2. (B) Lung squamous cell carcinoma specimen with high expression of YTHDF2

Additional file 3 of Hypoxia-mediated YTHDF2 overexpression promotes lung squamous cell carcinoma progression by activation of the mTOR/AKT axis

Additional file 3. Hypoxia-RT-qPCR-SK-MES-1

Additional file 2 of Hypoxia-mediated YTHDF2 overexpression promotes lung squamous cell carcinoma progression by activation of the mTOR/AKT axis

Additional file 2. Hypoxia-RT-qPCR-NCI-H226

Multi-Center Cooperativity Enables Facile C–C Coupling in Electrochemical CO₂ Reduction on a Ni₂P Catalyst

The increasing interest for renewable electricity-driven CO2 electroreduction calls for effective strategies in catalyst design, which have so far mainly focused on the compositional modulation such as doping and alloying. Recently, attention has turned to the microstructural tailoring of catalytic centers with a multi-center architecture to promote the formation of multi-carbon products, but theoretical understanding lags far behind the experimental discoveries. Herein, a systematic first principles study is performed on the representative electrocatalyst, Ni2P, which is characterized by densely distributed Ni3 catalytic centers and displays high selectivity to C–C coupling during CO2 reduction reaction (CO2RR). Not only the Ni atoms in each trinuclear Ni3 site can cooperatively accommodate reaction intermediates for better opportunities of their coupling, but the adjacent Ni3 sites can also work in synergy to drive the highly endothermic hydrogenation steps in forming critical multi-carbon species. At the core of this capability lies the participation of the hydrogen-bonding network of water in transferring surface protons between neighboring Ni3 sites, which builds a kinetically feasible path to circumvent the thermodynamic penalty in an electrochemical step. This work uncovers the mechanism by which cooperativity arises in multi-center microstructures, with implications generally for the design of CO2RR electrocatalysts to obtain valuable chemicals

Improved Photocatalytic Activities of g‑C₃N₄ Nanosheets by B Doping and Ru-Oxo Cluster Modification for CO₂ Conversion

g-C3N4 is a promising photocatalyst for CO2 conversion owing to its outstanding reduction potential. However, its shallow valence band position and sluggish water oxidation reaction restrict the overall CO2 photoreduction process. Herein, g-C3N4 nanosheets are first doped with B through thermal treatment of mixed NaBH4 and subsequently modified with highly dispersed Ru-oxo clusters by using tailored chitosan oligomers. The optimal Ru-oxo modified B-doped g-C3N4 exhibits an exceptional photocatalytic CO2 conversion rate with 22-fold improvement compared with pristine CN. Based on the results of electron paramagnetic resonance, atmosphere-controlled surface photovoltage spectroscopy, in situ diffuse reflectance infrared Fourier transform spectroscopy, etc., it is confirmed that the improved photoactivities are attributed to the downward shift of the valence band to obtain the strong driving force for water oxidation along with extension of the visible light response region by B doping and to the capture of photogenerated holes to enhance charge separation and then to accelerate the water oxidation process from the modified Ru-oxo clusters