Phosphate Molecules Research Articles

Structural analysis of the CJ0600 protein from Campylobacter jejuni

The Campylobacter jejuni bacterium, which causes foodborne enteritis in humans, expresses the uncharacterized protein CJ0600. Based on sequence analysis, CJ0600 has been proposed to function as a 1-aminocyclopropane-1-carboxylate (ACC) deaminase (AccDA) or cysteine desulfhydrase (CysDS). However, it has never been investigated whether CJ0600 exerts AccDA or CysDS activity or how CJ0600 mediates its enzymatic activity. To reveal the structural features necessary for the function of CJ0600, we determined the crystal structure of CJ0600 and characterized its enzymatic activity. CJ0600 contains two domains and features an interdomain pocket, which accommodates a pyridoxal 5′-phosphate (PLP) molecule as a Schiff base with its lysine residue (K35), as observed in its structural homologs, including AccDA, CysDS, and serine deaminase (SerDA). However, unlike its structural homologs, CJ0600 exists as a monomer and exhibits unique structural features throughout its structure. Moreover, CJ0600 contains unique active site residues that are not observed in AccDA, CysDS, or SerDA. Consistently, phylogenetic analysis indicates that CJ0600 and its orthologs are evolutionarily distinct from AccDA, CysDS, and SerDA. Indeed, CJ0600 showed no CysDS or SerDA activity and extremely weak AccDA activity. These observations suggest that CJ0600 functions as a unique PLP-dependent enzyme that has not been reported.

Effect of Electric Fields on the Decomposition of Phosphate Esters.

Phosphate esters decompose on metal surfaces and form protective polyphosphate films. For many applications, such as in lubricants for electric vehicles and wind turbines, an understanding of the effect of electric fields on molecular decomposition is urgently required. Experimental investigations have yielded contradictory results, with some suggesting that electric fields improve tribological performance, while others have reported the opposite effect. Here, we use nonequilibrium molecular dynamics (NEMD) simulations to study the decomposition of tri-n-butyl phosphate (TNBP) molecules nanoconfined between ferrous surfaces (iron and iron oxide) under electrostatic fields. The reactive force field (ReaxFF) method is used to model the effects of chemical bonding and molecular dissociation. We show that the charge transfer with the polarization current equalization (QTPIE) method gives more realistic behavior compared to the standard charge equilibration (QEq) method under applied electrostatic fields. The rate of TNBP decomposition via carbon-oxygen bond dissociation is faster in the nanoconfined systems than that in the bulk due to the catalytic action of the surfaces. In all cases, the application of an electric field accelerates TNBP decomposition. When electric fields are applied to the confined systems, the phosphate anions are pulled toward the surface with high electric potential, while the alkyl cations are pulled to the surface with lower potential, leading to asymmetric film growth. Analysis of the temperature- and electric field strength-dependent dissociation rate constants using the Arrhenius equation suggests that, on reactive iron surfaces, the increased reactivity under an applied electric field is driven mostly by an increase in the pre-exponential factor, which is linked to the number of molecule-surface collisions. Conversely, the accelerated decomposition of TNBP on iron oxide surfaces can be attributed to a reduction in the activation energy with increasing electric field strength. Single-molecule nudged-elastic band (NEB) calculations also show a linear reduction in the energy barrier for carbon-oxygen bond breaking with electric field strength, due to stabilization of the charged transition state. The simulation results are consistent with experimental observations of enhanced and asymmetric tribofilm growth under electrostatic fields.

Control of inorganic and organic phosphorus molecules on microbial activity, and the stoichiometry of nutrient cycling in soils in an arid, agricultural ecosystem

Background The dynamics of carbon (C), nitrogen (N), and phosphorus (P) in soils determine their fertility and crop growth in agroecosystems. These dynamics depend on microbial metabolism, which in turn depends on nutrient availability. Farmers typically apply either mineral or organic fertilizers to increase the availability of nutrients in soils. Phosphorus, which usually limits plant growth, is one of the most applied nutrients. Our knowledge is limited regarding how different forms of P impact the ability of microbes in soils to produce the enzymes required to release nutrients, such as C, N and P from different substrates. Methods In this study, we used the arable layer of a calcareous soil obtained from an alfalfa cropland in Cuatro Cienegas, México, to perform an incubation experiment, where five different phosphate molecules were added as treatments substrates: three organic molecules (RNA, adenine monophosphate (AMP) and phytate) and two inorganic molecules (calcium phosphate and ammonium phosphate). Controls did not receive added phosphorus. We measured nutrient dynamics and soil microbial activity after 19 days of incubation. Results Different P molecules affected potential microbial C mineralization (CO2-C) and enzyme activities, specifically in the organic treatments. P remained immobilized in the microbial biomass (Pmic) regardless of the source of P, suggesting that soil microorganisms were limited by phosphorus. Higher mineralization rates in soil amended with organic P compounds depleted dissolved organic carbon and increased nitrification. The C:N:P stoichiometry of the microbial biomass implied a change in the microbial community which affected the carbon use efficiency (CUE), threshold elemental ratio (TER), and homeostasis. Conclusion Different organic and inorganic sources of P affect soil microbial community structure and metabolism. This modifies the dynamics of soil C, N and P. These results highlight the importance of considering the composition of organic matter and phosphate compounds used in agriculture since their impact on the microbial activity of the soil can also affect plant productivity.

Chemoreactomic study of fonturacetam effects: molecular mechanisms of influence on adipose tissue metabolism

Objective: to conduct chemoreactomic, pharmacoinformatic and chemoneurocytological analyzes of the properties of racetams (piracetam, aniracetam, pramiracetam, levetiracetam, fonturacetam).Material and methods. Chemoreactomic, pharmacoinformatic and chemoneurocytological methods of molecule properties analyzis are based on chemoreactomic methodology – the latest direction in the application of machine learning systems in the field of postgenomic pharmacology. Analysis of pharmacological capabilities of molecules within the framework of chemoreactomic methodology is carried out by comparing the chemical structure of racetam molecules with the structures of molecules for which pharmacological properties were studied using training artificial intelligence algorithms based on big data information presented in PubChem, HMDB, STRING, PharmGKB databases. Based on the entire complex of differences between molecules in interactions with receptor proteins, an “anti-obesity” score was calculated for each one as a serial number of this molecule in descending order by corresponding IC50, EC50 chemoreactomic constants values.Results. The lipolytic effect is predicted specifically for fonturacetam as a result of activation by this molecule of β3-adrenoceptors, adenosine receptors, glucagon-like peptide, sphingosine phosphate and peroxisome proliferators, as well as specific inhibition of cannabinoid, opioid, histamine, glutamate, nociceptin, orexin and neuropeptide Y receptors. Due to these mechanisms fonturacetam will contribute to normalizing appetite and improving adipose tissue metabolism. The total lipolytic effect score was calculated for all established interactions with receptors and amounted to 4.3±0.9 for fonturacetam, 3.0±1.4 for pramiracetam, and 2.5±1.5 for all other molecules.Conclusion. The results of the analysis suggest that the lipolytic effects of fonturacetam (Actitropil – Pharmstandard, Russia) will be much stronger than for other racetams (piracetam, aniracetam, pramiracetam, levetiracetam). Chemoreactomic analysis of fonturacetam indicated new mechanisms of pharmacological action of the molecule, providing a decrease in excess appetite and body weight normalization. Fonturacetam is the only nootropic drug indicated for the treatment of obesity.

Efficient Quasi-Two-Dimensional Perovskite Light-Emitting Diodes Achieved through the Passivation of Multi-Fluorine Phosphate Molecules.

The surface morphology of perovskite films significantly influences the performance of perovskite light-emitting diodes (PeLEDs). However, the thin perovskite thickness (~10 nm) results in low surface coverage on the substrate, limiting the improvement of photoelectric performance. Here, we propose a molecular additive strategy that employs pentafluorophenyl diphenylphosphinate (FDPP) molecules as additives. P=O and Pentafluorophenyl (5F) on FDPP can coordinate with Pb2+ to slow the crystallization process of perovskite and enhance surface coverage. Moreover, FDPP reduces the defect density of perovskite and enhances the crystalline quality. The maximum brightness, power efficiency (PE), and external quantum efficiency (EQE) of the optimal device reached 24,230 cd m-2, 82.73 lm W-1, and 21.06%, respectively. The device maintains an EQE of 19.79% at 1000 cd m-2 and the stability is further enhanced. This study further extends the applicability of P=O-based additives.

Highly Adaptive Flame‐Retardant Electrolyte Endows Hard‐Carbon Anodes with Stable Interface Structure for High‐Safety Sodium‐Ion Batteries

Hard carbon (HC) is the most promising anode material for sodium‐ion batteries (SIBs). The main obstacle to HC's application is its incompatibility with the phosphate flame‐retardant additive, a common SIB additive. This incompatibility arises from the unstable solid electrolyte interphase (SEI) caused by phosphate molecule decomposition. For the first time, in this work, a new type of highly adaptive flame‐retardant electrolyte is proposed. The electrolyte ensures the stability of the electrode/electrolyte interface by the introduction of pioneering long‐chain nitrile as the SEI‐forming additive and solvated structural regulator. Long‐chain nitriles decompose before phosphate and form a stable SEI containing N element, which prevents the phosphate from inserting into the HC's layers and reduces its sodium‐storage capacity. As a proof of concept, the HC anode demonstrates a higher initial Coulombic efficiency of 80.78% in the as‐designed highly adaptive flame‐retardant electrolyte, which is about 1.8 times than that before regulation. It can cycle stably for 1250 cycles at 3 C with a capacity retention of 60%. Moreover, the electrolyte has good flame retardancy and can extinguish naturally within 1 s. In this work, an innovative method is provided for developing high‐safety SIBs based on HC anodes.

Synthesis and application of anthraquinone quaternary phosphonium salt electroplating copper leveler based on expanded electrostatic adsorption area strategy and physicochemical salt bridge mechanism

Four anthraquinone quaternary phosphate molecules (AQS-a, AQS-b, AQS-c, AQS-d) with different electrostatic adsorption areas were constructed as electroplating levelers based on the strategy of expanding the electrostatic adsorption area of the molecules. AQS-d with the largest electrostatic adsorption area was demonstrated to have the most excellent electrochemical performance by electrochemical tests. The physicochemical adsorption sites and interactions with copper ions of AQS levelers were proposed by theoretical calculations, molecular dynamics simulations, Raman spectroscopy and fluorescence absorption spectroscopy, and the electroplating salt bridge mechanism was proposed. Based on optical microscope, scanning electron microscope, atomic force microscope and X-ray diffractometer, it is proved that AQS-d has the ability to perfectly fill the microvia in actual plating by actual PCB blind hole filling experiment.

Effects of Hypoxia and Reoxygenation on Metabolic Profiles of Cardiomyocytes.

In vitro cellular models provide valuable insights into the adaptive biochemical mechanisms triggered by cells to cope with the stress situation induced by hypoxia and reoxygenation cycles. The first biological data generated in studies based on this micrometric life-scale has the potential to provide us a global overview about the main biochemical phenomena presented in some reported preconditioning therapies in life-scale of higher dimensions. Thus, in this study, a cell incubator was designed and manufactured to produce a cellular model of heart hypoxia followed by reoxygenation (HfR) through consecutive repetitions of hypoxia-normoxia gas exchange. Samples of cellular extracts and culture media were obtained from non-proliferative cardiomyocytes (CMs) cultivated under challenging HfR (stressed CMs) and regular cultivation (unstressed CMs) in rounds of four days for each case. Metabolomic based on proton magnetic resonance spectroscopy (1H-MRS) was used as an analytical approach to identify and quantify the metabolomes of these samples, the endo- and exo-metabolome. Despite the stressed CMs presented over 90% higher cellular death rate compared to the unstressed CMs, the metabolic profiles indicates that the surviving cells up-regulate their amino acid metabolism either by active protein degradation or by the consumption of culture media components to increase coenzyme A-dependent metabolic pathways. This cell auto-regulation mechanism could be well characterized in the first two days when the difference smears off under once the metabolomes become similar. The metabolic adaptations of stressed CMs identified the relevance of the cyclic oxidation/reduction reactions of nicotinamide adenine dinucleotide phosphate molecules, NADP+/NADPH, and the increased tricarboxylic acid cycle activity in an environment overloaded with such a powerful antioxidant agent to survive an extreme HfR challenge. Thus, the combination of cellular models based on CMs, investigative methods, such as metabolomic and 1H-MRS, and the instrumental development of hypoxia incubator shown in this work were able to provide the first biochemical evidences behind therapies of gaseous exchanges paving the way to future assays.

Impacts of Eutrophication and Global Warming on the Emergence of Toxic Cyanobacteria blooms

Cyanobacteria, the oldest phytoplankton on the planet, cause toxic algal blooms in freshwater, estuarine, marine and fresh water habitats. According to recent study, eutrophication and climate change may contribute to the spread of dangerous cyanobacterial algae blooms. This study examines the correlation between eutrophication, climate change, and cyanobacterial taxa in freshwater (Microcystis, Anabaena, Cylindrospermopsis). Cyanobacterial genera have the capacity to compete for low inorganic phosphate concentrations and acquire organic phosphate molecules. Cyanobacteria, both diazotrophic (nitrogen (N2) fixers) and non-diazotrophic, may create blooms using a wide range of nitrogen sources. Some cyanobacterial blooms are linked to eutrophication, although others occur at low inorganic N and P concentrations. Cyanobacteria dominate phytoplankton assemblages at higher temperatures due to physiological (e.g., faster growth) and physical reasons (e.g., greater stratification), with distinct species exhibiting various temperature peaks. The impact of rising carbon dioxide (CO2) concentrations on cyanobacteria is unclear. However, some research shows that some genera of cyanobacteria thrive in low CO2 environments. Future eutrophication and climate change are expected to increase the frequency and size of dangerous cyanobacterial blooms, despite their complicated interactions

Structural and functional properties of uridine 5′-monophosphate synthase from Coffea arabica

In higher eukaryotes and plants, the last two sequential steps in the de novo biosynthesis of uridine 5′-monophosphate (UMP) are catalyzed by a bifunctional natural chimeric protein called UMP synthase (UMPS). In higher plants, UMPS consists of two naturally fused enzymes: orotate phosphoribosyltransferase (OPRTase) at N-terminal and orotidine-5′-monophosphate decarboxylase (ODCase) at C-terminal. In this work, we obtained the full functional recombinant protein UMPS from Coffea arabica (CaUMPS) and studied its structure-function relationships. A biochemical and structural characterization of a plant UMPS with its two functional domains is described together with the presentation of the first crystal structure of a plant ODCase at 1.4 Å resolution. The kinetic parameters measured of CaOPRTase and CaODCase domains were comparable to those reported. The crystallographic structure revealed that CaODCase is a dimer that conserves the typical fold observed in other ODCases from prokaryote and eukaryote with a 1-deoxy-ribofuranose-5′-phosphate molecule bound in the active site of one subunit induced a closed conformation. Our results add to the knowledge of one of the key enzymes of the de novo biosynthesis of pyrimidines in plant metabolism and open the door to future applications.

Adsorptive Removal of Phosphate from Agricultural Effluent using Thermally and Non-Thermally Activated Sepiolite Clay

This study assessed the use of thermally activated sepiolite clay (TASC) and non-activated sepiolite clay (NASC) as adsorbents for phosphate adsorption from agricultural effluent. The effect of pH, temperature, dosage, and time on the adsorbates was investigated at pH 4-11, temperature 298 - 318k, contact time 30 – 120 minutes, and adsorbent dosage 0.2 - 4 g in 100 mL of agricultural effluent. Fourier-transformed infrared spectroscopy (FTIR) and Scanning electron microscope (SEM) techniques were used to determine adsorbent features. TASC and NASC exhibit an excellent capacity for adsorbing phosphate molecules. At equilibrium, the removal efficiency of phosphate at 4 different varying conditions of temperature, pH, adsorbent dosage, and time gave more than 100 % for TASC, while NASC also recorded over 100% adsorption of phosphate at 3 different varying conditions. The amount of phosphate adsorbed was found to decrease with an increase in temperature and contact time. The isotherm adsorption data fitted the Langmuir better than the Freundlich model, where the correlation coefficients of Langmuir and Freundlich were 0.9994 and 0.8901, respectively. The adsorption kinetics was better explained by the pseudo-first-order kinetic model with R2 values TASC (0.9999) and NASC (0.9999) than the second order with R2 value TASC (0.9984) and NASC (0.9820).

Kyasanur Forest disease virus NS3 helicase: Insights into structure, activity, and inhibitors

Kyasanur Forest disease virus (KFDV), a tick-borne flavivirus prevalent in India, presents a serious threat to human health. KFDV NS3 helicase (NS3hel) is considered a potential drug target due to its involvement in the viral replication complex. Here, we resolved the crystal structures of KFDV NS3hel apo and its complex with three phosphate molecules, which indicates a conformational switch during ATP hydrolysis. Our data revealed that KFDV NS3hel has a higher binding affinity for dsRNA, and its intrinsic ATPase activity was enhanced by dsRNA while being inhibited by DNA. Through mutagenesis analysis, several residues within motifs I, Ia, III, V, and VI were identified to be crucial for NS3hel ATPase activity. Notably, the M419A mutation drastically reduced NS3hel ATPase activity. We propose that the methionine-aromatic interaction between residues M419 and W294, located on the surface of the RNA-binding channel, could be a target for the design of efficient inhibitor probes. Moreover, epigallocatechin gallate (EGCG), a tea-derived polyphenol, strongly inhibited NS3hel ATPase activity with an IC50 value of 0.8 μM. Our computational docking data show that EGCG binds at the predicted druggable hotspots of NS3hel. Overall, these findings contribute to the development and design of more effective and specific inhibitors.

Suppression of Interphase Dissolution Via Solvent Molecule Tuning for Sodium Metal Batteries.

Solvent molecule tuning is used to alter the redox potentials of solvents or ion-solvent binding energy for high-voltage or low-temperature electrolytes. Herein, an electrolyte design strategy that effectively suppresses solid electrolyte interphase (SEI) dissolution and passivates highly-reactive metallic Na anode via solvent molecule tuning is proposed. With rationally lengthened phosphate backbones with ─CH2 ─ units, the low-solvation tris(2-ethylhexyl) phosphate (TOP) molecule effectively weakens the solvation ability of carbonate-based electrolytes, reduces the free solvent ratio, and enables an anion-enriched primary Na+ ion solvation sheath. The decreased free solvent and compact lower-solubility interphase established in this electrolyte prevent electrodes from continuous SEI dissolution and parasitic reactions at both room temperature (RT) and high temperature (HT). As a result, the Na/Na3 V2 (PO4 )3 cell with the new electrolyte achieves impressive cycling stability of 95.7% capacity retention after 1800 cycles at 25 °C and 62.1% capacity retention after 700 cycles at 60°C. Moreover, the TOPmolecule not only maintains the nonflammable feature of phosphate but also attains higher thermal stability, which endows the electrolyte with high safety and thermal stability. This design concept for electrolytes offers a promising path to long-cycling and high-safetysodium metal batteries.

A human pilot study on positive electrostatic charge effects in solid tumors of the late-stage metastatic patients.

Correlative interactions between electrical charges and cancer cells involve important unknown factors in cancer diagnosis and treatment. We previously reported the intrinsic suppressive effects of pure positive electrostatic charges (PEC) on the proliferation and metabolism of invasive cancer cells without any effect on normal cells in cell lines and animal models. The proposed mechanism was the suppression of pro-caspases 3 and 9 with an increase in Bax/Bcl2 ratio in exposed malignant cells and perturbation induced in the KRAS pathway of malignant cells by electrostatic charges due to the phosphate molecule electrostatic charge as the trigger of the pathway. This study aimed to examine PECs as a complementary treatment for patients with different types of solid metastatic tumors, who showed resistance to chemotherapy and radiotherapy. In this study, solid metastatic tumors of the end-stage patients (n = 41) with various types of cancers were locally exposed to PEC for at least one course of 12 days. The patient's signs and symptoms, the changes in their tumor size, and serum markers were followed up from 30 days before positive electrostatic charge treating (PECT) until 6 months after the study. Entirely, 36 patients completed the related follow-ups. Significant reduction in tumor sizes and cancer-associated enzymes as well as improvement in cancer-related signs and symptoms and patients' lifestyles, without any side effects on other tissues or metabolisms of the body, were observed in more than 80% of the candidates. PECT induced significant cancer remission in combination with other therapies. Therefore, this non-ionizing radiation would be a beneficial complementary therapy, with no observable side effects of ionizing radiotherapy, such as post-radiation inflammation.

Functional Group-Dependent Proton Conductivity of Phosphoric Acid-Doped Ion-Pair Coordinated Polymer Electrolytes: A Molecular Dynamics Study.

Toward deployment of high-temperature polymer electrolyte membrane fuel cells (HT-PEMFCs) in our daily lives, multiple research efforts have been dedicated to develop high-performance phosphate-doped polymer electrolytes. Recently, ion-pair coordinated polymers have garnered attention for their high stability and proton conductivity. However, a comprehensive understanding of how proton transport properties are modified by the functional groups present in these polymers is still lacking. In this study, we employ molecular dynamics (MD) simulations to investigate the impact of different functional group types and conversion ratios on conductivity. We find that Grotthuss-type hopping transport predominantly governs the overall conductivity, surpassing vehicular transport by factors of 100-1000. As conductivity scales with proton concentration, we observe that less-bulky functional groups offer advantages by minimizing the volume expansion associated with increased conversion ratios. Additionally, we show that a strong ion-pair interaction between the cationic functional group and the phosphate anion disrupts the suitable intermolecular orientations required for efficient proton hopping between phosphate and phosphoric acid molecules, thereby diminishing the proton conductivity. Our study underscores the importance of optimizing the strength of ion-pair interactions to balance stability and proton conductivity, thus paving the way for the development of ion-pair coordinated polymer electrolytes with improved performance.

Elucidating the Mechanism of Large Phosphate Molecule Intercalation Through Graphene-Substrate Heterointerfaces.

Intercalation is the process of inserting chemical species into the heterointerfaces of two-dimensional (2D) layered materials. While much research has focused on the intercalation of metals and small gas molecules into graphene, the intercalation of larger molecules through the basal plane of graphene remains challenging. In this work, we present a new mechanism for intercalating large molecules through monolayer graphene to form confined oxide materials at the graphene-substrate heterointerface. We investigate the intercalation of phosphorus pentoxide (P2O5) molecules directly from the vapor phase and confirm the formation of confined P2O5 at the graphene-substrate heterointerface using various techniques. Density functional theory (DFT) corroborates the experimental results and reveals the intercalation mechanism, whereby P2O5 dissociates into small fragments catalyzed by defects in the graphene that then permeates through lattice defects and reacts at the heterointerface to form P2O5. This process can also be used to form new confined metal phosphates (e.g., 2D InPO4). While the focus of this study is on P2O5 intercalation, the possibility of intercalation from predissociated molecules catalyzed by defects in graphene may exist for other types of molecules as well. This in-depth study advances our understanding of intercalation routes of large molecules via the basal plane of graphene as well as heterointerface chemical reactions leading to the formation of distinctive confined complex oxide compounds.

From liquid to crystal via mechanochemical grinding: unique host-guest (HOF) cocrystal.

Mechanochemical synthesis via grinding of trimesic acid (TA, C9H6O6) and 4-chlorophenyl diphenyl phosphate (4CDP, C18H14ClO4P) (liquid at room temperature) in a 1:1 ratio resulted in the formation of an inclusion type of cocrystal. The crystallization of this phase via slow evaporation at low temperature (276-277 K) from methanol resulted in a rare `stairstep morphology' during the process of crystal growth. This morphology was not observed after crystallization of the compound from other solvents like toluene, dichloromethane, acetone, hexane and isooctane, and hence this was characteristically observed in methanol only. The characterization from single-crystal X-ray diffraction revealed the formation of a cocrystal with five molecules of TA and two molecules of 4CDP in the asymmetric unit. The trimesic acid molecules form hydrogen-bonded dimers resulting in hexagonal rings, and these rings are stacked through π-π intermolecular interactions to make a hexagonal honeycomb-like structure. The phosphate molecules, 4CDP, were found to be trapped as guests in these hexagonal channels. The similarity in the packing of trimesic acid is compared in the cocrystal and the free acid quantitatively via Xpac analysis, which establishes the relationship of a `2D supramolecular construct' between them. This signifies a unique type of arrangement in which the voids created by the trimesic acid moiety do not undergo distortion by the inclusion of the guest molecules. The quantitative analysis of the intermolecular interactions using Hirshfeld surfaces and fingerprint plots deciphers the role of both strong O-H...O hydrogen bonds and weak intermolecular interactions in the crystal packing.

The role of reactive phosphate species in the abatement of micropollutants by activated peroxymonosulfate in the treatment of phosphate-rich wastewater.

This study investigated the mechanisms of forming reactive species to degrade micropollutants through the activation of peroxymonosulfate (PMS) by phosphate, a prevalent ion in wastewater. Considering the density functional theory results, the formation of hydrogen bonds between phosphate and PMS molecules might be the crucial step in the overall reactions, which prefers producing ⋅OH and reactive phosphate species (RPS, namely H2PO4⋅, HPO4⋅-, and PO4⋅2-) to yielding SO4⋅-. Besides, in the phosphate (5mM)/PMS system at pH=8, HPO4⋅- was modeled to be the dominant radical with a steady-state concentration of 3.6×10-12M, which was 666 and 773 times higher than those of ⋅OH and SO4⋅-. The contributions of 1O2, ⋅OH, SO4⋅-, and RPS to the micropollutant decomposition in phosphate/PMS were studied, and RPS were found to be selective for micropollutants with electron-donating moieties (such as phenolic and aniline groups). Additionally, the degradation pathways of bisphenol A, diclofenac, ibuprofen, and atrazine in phosphate/PMS were proposed according to the detected transformation products. Cytotoxicity analysis was carried out to evaluate the potential environmental impacts resulting from the degradation of micropollutants by phosphate/PMS. This study confirmed the significance of RPS for micropollutant degradation during PMS-based treatment in phosphate-rich scenarios.

A hybrid off-lattice kinetic Monte Carlo/molecular dynamics method for amorphous thin film growth

The ability to understand and model the growth of amorphous thin films on solid surfaces is essential to a wide range of industrial applications, from the deposition of wear-resistant coatings to the production of solar cells. Here, a three-dimensional (3D) hybrid off-lattice kinetic Monte Carlo/molecular dynamics (kMC/MD) algorithm is developed to study the growth of thin amorphous films on solid substrates with atomistic resolution over timescales of tens of seconds. We use this method to study the growth of polyphosphate films from tricresyl phosphate (TCP) molecules on an iron substrate. Molecular adsorption/desorption, bond breaking/formation processes, and diffusion of iron ions through the film are simulated in the kMC stage and the film is relaxed during the MD stage. The kMC/MD method is approximately eleven orders of magnitude faster than equivalent reactive force field (ReaxFF) MD simulations. The simulated film growth rate and topology agree well with experimental results and the chemical structure of the film is consistent with previous molecular dynamics simulations of iron polyphosphates. The newly-developed hybrid kMC/MD methodology can be adapted to yield important insights into thin film growth for several other potential applications.

Photoelectron "Bridge" in Van Der Waals Heterojunction for Enhanced Photocatalytic CO2 Conversion Under Visible Light.

Constructing Van der Waals heterojunction is a crucial strategy to achieve excellent photocatalytic activity. However, in most Van der Waals heterojunctions synthesized by ex situ assembly, electron transfer encounters huge hindrances at the interface between the two components due to the large spacing and potential barrier. Herein, a phosphate-bridged Van der Waals heterojunction of cobalt phthalocyanine (CoPc)/tungsten disulfide (WS2 ) bridged by phosphate (xCoPc-nPO4 - -WS2 ) is designed and prepared by the traditional wet chemistry method. By introducing a small phosphate molecule into the interface of CoPc and WS2 , creates an electron "bridge", resulting in a compact combination and eliminating the space barrier. Therefore, the phosphate (PO4 - ) bridge can serve as an efficient electron transfer channel in heterojunction and can efficiently transmit photoelectrons from WS2 to CoPc under excited states. These excited photoelectrons are captured by the catalytic central Co2+ in CoPc and subsequently convert CO2 molecules into CO and CH4 products, achieving17-fold enhancement on the 3CoPc-0.6PO4 - -WS2 sample compared to that of pure WS2 . Introducing a small molecule "bridge" to create an electron transfer channel provides a new perspective in designing efficient photocatalysts for photocatalytic CO2 reduction into valuable products.