Theoretical study on the degradation mechanism of perfluoro-ethanesulfonic acid under subcritical hydrothermal alkaline conditions.

Perfluorosulfonic acid, a widely recognized persistent organic pollutant, has attracted significant attention due to its severe environmental contamination, necessitating urgent resolution. To discover effective degradation strategies, this study implemented density functional theory, utilizing Gaussian 09 software with the WB97XD/6-311++G(2d,2p)//CCSD(T)/6-311++G(2df,2p) computational approach to conduct an in-depth reaction pathway analysis of perfluoroethane sulfonic acid (PFEtS) under subcritical hydrothermal alkaline conditions. It was revealed that PFEtS exhibits an uneven electron density distribution along the carbon chain backbone, with the bond energy of the C2-F4 bond being the lowest, followed by the C1-F1 bond, and the S-C1 bond energy being lower than those of C1-C2 and C-F bonds, rendering it susceptible to breakage. Based on these observations, seven potential degradation pathways of PFEtS were proposed under subcritical hydrothermal alkaline conditions, following optimization, and five reaction pathways have been identified. The degradation process unfolds in two stages. Initially, hydroxyl groups replace the sulfonate in PFEtS to form perfluoroethanol. Subsequently, full mineralization is achieved under alkaline conditions. The most probable reaction pathway involves hydroxyl groups attacking the C1 position, resulting in the generation of CO2 and inorganic fluoride ions. The first step of the reaction is the rate-determining step, with a theoretical rate constant calculated to be 8.41 × 10-5 L mol-1 s-1. This theoretical value is in close agreement with the experimentally determined degradation rate constant of perfluorooctane sulfonate under identical conditions, which is 8.67 × 10-4 L mol-1 s-1. This finding corroborates the experimental observation that longer-chain perfluoro-sulfonates degrade faster than their shorter-chain counterparts.

Hypofunction of macrophage chemotaxis contributes to defective efficacy of herceptin in HER2-positive breast cancer patients.

Breast cancer was considered as a kind of prone breast tumors with the complicated pathological mechanisms and diverse clinical classifications. In the clinical treatments of HER2-positive tumor patients, HER2 monoclonal antibodies, such as Herceptin, have shown well-defined therapeutic effects. Nevertheless, due to the heterogeneity of breast cancers, drug resistance inevitably appeared during the application of Herceptin. In order to fully understand the immune tolerance status of the tumor microenvironment in the population of sensitive and insensitive patients, this study carried out a series of studies through Luminex cytokines assay, clinicopathological analysis, immunofluorescence, and PCR. The results confirmed that in clinical samples sensitive to Herceptin, there were a large number of macrophages, and the protein expression levels and in situ expression of macrophage-related chemokines and inflammatory mediators are significantly higher than drug-resistant tumor samples. Further studies found that T cell function has a low correlation with tumor growth, and there are obvious obstacles in the process of peripheral blood immune cells entering the tumor microenvironment. In summary, this study provided clues for understanding the clinical drug resistance of HER2 monoclonal antibody and the clinical rational use of drugs and combination drugs.

Suzuki-Miyaura Type Regioselective C-H Arylation of Aromatic Aldehydes by a Transient Directing Strategy.

Herein, we disclose a common approach for palladium-catalyzed direct coupling of the ortho-C-H bond of aromatic aldehydes with various organoboronic reagents by a transient directing strategy. In contrast to widely used cross-coupling reactions of C-H bonds with aryl halides, which generally need silver salt as a halide removal reagent, the method which used BQ/TFA as weak oxidation system for the PdII/Pd0 redox cycle is cost-effective, ecofriendly, and more aligned with green catalysis. This broadly applicable method opens up a new and efficient Suzuki-Miyaura coupling route for the direct formation of carbon-carbon bonds by C-H bond activation.

Paliperidone Palmitate versus Risperidone Long-Acting Injectable in Patients with Schizophrenia: A Meta-Analysis of Efficacy and Safety.

Purpose: The aim of this study was to assess the efficacy and safety of paliperidone palmitate (PP) treatment compared with risperidone long-acting injectable (LAI) treatments for patients with schizophrenia. Patients and Methods: Data mining was conducted in April 2022 across PubMed, Web of Science, Embase, the Cochrane Library, ClinicalTrials.gov, and PsycINFO. All published randomized controlled trials (RCTs) that assessed the effect of PP treatment for patients with schizophrenia when compared with the risperidone-LAIAs group were included. Relevant data were extracted and synthesized narratively. Results were expressed as standardized mean differences (SMDs) or risk ratios (RRs), with 95% confidence intervals (CIs). Results: Four RCTs with 2451 patients met all the inclusion and exclusion criteria. Efficacy analyses showed no significant statistical differences in Positive and Negative Syndrome Scale (PANSS) total score changes at the endpoint (SMD = 0.10, P = 0.19), or in response rates (RR = 0.93; P = 0.40). Regarding the safety outcomes, PP treatment showed significantly increased risks of discontinuation rates for any reason (35.7% vs 30.4%; RR = 1.19; 95% CI, 1.03 to 1.39; P = 0.02) and nonsignificantly increased risks of total treatment emergent adverse events (TEAEs) (66.6% vs.64.8%; RR = 1.01; 95% CI, 0.94 to 1.09; P = 0.78) compared with the risperidone-LAIAs-treated group. Furthermore, PP may significantly increase total discontinuation rates compared with risperidone-LAIAs. Conclusion: Our meta-analysis did not find a more beneficial effect of PP compared to risperidone-LAIAs treatments for schizophrenia. Clinicians should interpret and translate our data with caution, as the meta-analysis was based on a limited number of randomized controlled trials and patients.

Copper-Catalyzed Transamidation of Unactivated Secondary Amides via C-H and C-N Bond Simultaneous Activations.

Here, we demonstrate that α-C-H and C-N bonds of unactivated secondary amides can be activated simultaneously by the copper catalyst to synthesize α-ketoamides or α-ketoesters in one step, which is a challenging and underdeveloped transformation. Using copper as a catalyst and air as an oxidant, the reaction is compatible with a broad range of acetoamides, amines, and alcohols. The preliminary mechanism studies and density functional theory calculation indicated that the reaction process may undergo first radical α-oxygenation and then transamidation with the help of the resonant six-membered N,O-chelation and molecular oxygen plays a role as an initiator to trigger the transamidation process. The combination of chelation assistance and dioxygen selective oxygenation strategy would substantially extend the modern mild synthetic amide cleavage toolbox, and we envision that this broadly applicable method will be of great interest in the biopharmaceutical industry, synthetic chemistry, and agrochemical industry.

Porous Electrospun Films with Reversible Photoresponsive Microenvironmental Humidity Regulation: A Controllable Hydrogen-Bonding Synergistic Effect Exhibited by Acrylic Acid Segments.

Suitable relative humidity is essential for the preservation of cultural relics, food storage, and so on. A special material that can regulate the relative humidity in the microenvironment is particularly important. In this work, several innovative electrospun films with reversible photoresponsive wettability and the ability to regulate microenvironmental relative humidity were prepared. The spiropyran unit of the synthesized copolymer played the most important role in humidity regulation due to its reversible transition between a nonpolar ring-closed state and a polar ring-opened state induced by alternating ultraviolet/visible illumination. More interestingly, the introduction of acrylic acid segments exhibited a controllable hydrogen bond synergistic effect for increasing the range of humidity regulation. The color change and the reversible change ranges of wettability and microenvironmental relative humidity under ultraviolet/visible irradiation are all closely related to the number of acrylic acid segments. Cassie theory, density functional theory (DFT), and interaction region indicator (IRI) analysis were used to characterize this phenomenon. Electrospinning is a promising method to achieve large-scale production that can put such material into practical applications.

Thermal transport in porous graphene with coupling effect of nanopore shape and defect concentration.

Thermal conductivity of porous graphene can be affected by defect concentration, nanopore shape and distribution, and it is hard to clarify the effects due to the correlation of those factors. In this work, molecular dynamics simulation is used to compare the thermal conductivity of graphene with three shapes of regularly arranged nanopores. The results prove the dominant role of defect concentration under certain circumstances in reducing thermal conductivity, while the coupling effect of nanopore shape should be noticed. When the atoms at the local phonon scattering area around each nanopore are properly removed, the abnormal increment of thermal conductivity can be detected with the increase of defect concentration. Heat flux vector angles can effectively characterize the local phonon scattering area, which can be used to describe the effect of nanopore shape. The coupling effect of defect concentration and pore shape with similar heat flux path is clarified according to this process. By adjusting vertex angle of triangle defect, there is a balanced state of the effect factors between the variation of defect concentration and the same phonon scattering area. It provides a possible way to describe the weighing factors of the coupling effect. The results suggest a feasible approach to optimize and regulate thermal properties of porous graphene in nanodevice.

The effect of (H2O)n (n = 1-3) clusters on the reaction of HONO with HCl: a mechanistic and kinetic study.

The reaction between HONO and HCl is a possible pathway for the generation of ClNO, which is prone to photolyze, produce chlorine radicals, and accelerate the oxidation of tropospheric VOCs. Current experimental and theoretical studies have significant differences in rate constants under similar conditions. This study aims to examine the reasons for this difference. In this study, the effects of a single water molecule, water dimer, water trimer, excess HCl and excess HONO on the reaction mechanism of HONO + HCl were studied at the CCSD(T)/aug-cc-pVTZ//M06-2X/6-311+G(2df,2p) level and the rate constants of each reaction channel were calculated. Our results showed that the reaction potential barrier of HONO with HCl was the lowest only when the water dimer was present, and the reaction rate constants were close to the experimental results, and both the cis-HONO⋯(H2O)2 + HCl and the trans-HONO⋯(H2O)2 + HCl reaction paths are likely to occur. We think that the reason for the inconsistency between experimental and theoretical results is that the water dimer is involved in the reaction in experiments.

Water-Tolerant Boron-Substituted MCM-41 for Oxidative Dehydrogenation of Propane.

Boron-based catalysts for oxidative dehydrogenation of propane (ODHP) have displayed excellent olefin selectivity. However, the drawback of deboronation leading to catalyst deactivation limited their scalable applications. Hereby, a series of mesoporous B-MCM-41 (BM-x, B/Si = 0.015-0.147) catalysts for ODHP were prepared by a simple hydrothermal synthesis method. It was found that propane conversion was increased and the initial reaction temperature was reduced with an increase of boron content, and the optimal values appeared on BM-2.0 (B/Si = 0.062), while olefins' (ethylene and propylene) selectivity was maintained at ca. 70-80%. Most importantly, BM-1.0 (B/Si = 0.048) exhibited favorable activity, stability, and water tolerance after washing treatment or long-time operation (e.g., propane conversion of ca. 15% and overall olefin selectivity of ca. 80% at 550 °C) because its high structural stability prevented boron leaches. These features were identified by X-ray diffraction (XRD), N2 physisorption, inductively coupled plasma-mass spectrometry (ICP-MS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and solid-state magic-angle-spinning nuclear magnetic resonance (MAS NMR) spectroscopy studies. The tri-coordinated B-OH species incorporated into the mesoporous silica framework are considered to be the active sites for ODHP.

Species of iron in the sediments of the Yellow River and its effects on release of phosphorus.

Species of Fe in the sediments from 21 sections of the Yellow River have been analyzed utilizing the so-called sequential extraction approach. The correlation between iron and phosphorus was analyzed, and the risk of release phosphorus was predicted. The results show that the content of residual iron (Feresidual) in the sediments is the highest, accounting for more than 92.55% of total iron (∑Fe) (the sum of the iron contents in each form is the total iron). Ca-bound phosphorous (PCa) is equal to the sum of authigenic calcium and phosphorus (Paut) and detritus calcium phosphorus (PDe), accounting for more than 73.01% of ∑P, in which PDe accounts for more than 90.91% of PCa, which is the main component of PCa and the main component of ∑P; Fewater in sediments is closely related to Porg, and Feex is closely related to Pex and PAl, which is an important factor to control the release of endogenous phosphorus. The extremely significant positive correlation between Feresidual and Paut and PDe in sediments is that they are affected by complex geological conditions in the Yellow River Basin. Judging by the ratio of ∑Fe/∑P combined with the influence of human factors, the release of phosphorus in sediments of most reaches of the Yellow River is controlled by iron, while the release of phosphorus is inhibited. Sediments in Xigu section H4, Zhongwei section H5, Haibowan section H7, three Sanshenggong section H8, Liulin section H13, and Tongguan section H16 of the Yellow River have certain phosphorus release risks, because phosphorus release is not only controlled by iron but also influenced by human factors, such as industrial and agricultural production level and artificial dam construction.

How to Stabilize a Heptagon-Containing C80 Cage by Endohedral Derivation.

Nonclassical fullerene is a new member of the fullerene family. In the present work, a systematic investigation on LaxSc3-xN@C80 (x = 0-3) covering both classical and nonclassical C80 cages was performed utilizing density functional theory combined with statistical mechanics. At absolute zero, LaSc2N@Hept(6)-Cs(2)-C80 with a heptagon-containing nonclassical carbon is the second most stable isomer, whereas at the temperature range of endohedral metallofullerene (EMF) formation, due to the large vibrational frequencies, LaSc2N@Hept(6)-Cs(2)-C80 is the third most abundant isomer, and its mole fraction is very low, accounting for the low experimental yield of LaSc2N@Hept(6)-Cs(2)-C80; La2ScN@Hept(6)-Cs(2)-C80, and La3N@Hept(6)-Cs(2)-C80 are the overwhelming isomers of the corresponding series, but compared with the cases of Sc3N@C80 and LaSc2N@C80, La2ScN and La3N clusters suffer much larger constraints from the C80 cages, perhaps preventing the synthesis of La2ScN@C80 and La3N@C80 species. Because of the large mole fractions and large electron donation and back-donation of La2ScN@Hept(6)-Cs(2)-C80 and La3N@Hept(6)-Cs(2)-C80, it can be inferred that La2ScN and La3N clusters may be used to stabilize some other larger nonclassical fullerene cages. This work will provide useful insights into the origins of stabilization of nonclassical fullerene cages by endohedral derivation and guidelines for synthesis EMF with nonclassical cages.

Pivotal Role of Nonmetal Atoms in the Stabilities, Geometries, Electronic Structures, and Isoelectronic Chemistry of Sc3 X@C80 (X = C, N, and O).

The thermodynamic and dynamic stabilities of Sc3 X@C80 (X = C, N, and O) are explored via density functional theory combined with statistical thermodynamic analysis and ab initio molecular dynamics. It is the first time to comprehensively consider the effect of nonmetal atoms on trimetallic endohedral clusterfullerenes. Relative to Sc3 X@Ih (31924)-C80 (X = N and O) with general six-electron transfer, an intriguing electronic structure of unexplored Sc3 C@D5h (31923)-C80 with thermodynamic and dynamic stabilities is clearly disclosed. Natural bond orbitals and charge decomposition analysis simultaneously suggest that one unpaired electron appears on the cage for neutral Sc3 C@D5h (31923)-C80 , which could be prospectively stabilized by effective exohedral derivatization and ionization in the future. Moreover, isoelectronic endohedral clusterfullerenes, (Sc3 C@C80 )- , Sc3 N@C80 , and (Sc3 O@C80 )+ , are also uniquely taken into account. The geometries, electronic structures, reactivities, and reactive sites of isoelectronic species are examined, and it turns out that all the three isoelectronic species would rather electrophilic than nucleophilic reactions. © 2019 Wiley Periodicals, Inc.

Progressively Exposing Active Facets of 2D Nanosheets toward Enhanced Pseudocapacitive Response and High-Rate Sodium Storage.

Sodium-ion batteries are gradually regarded as a prospective alternative to lithium-ion batteries due to the cost consideration. Here, three kinds of tin (IV) sulfide nanosheets are controllably designed with progressively exposed active facets, leading to beneficial influences on the Na+ storage kinetics, resulting in gradient improvements of pseudocapacitive response and rate performance. Interestingly, different forms of kinetics results are generated accompanying with the morphology and structure evolution of the three nanosheets. Finally, detailed density functional theory simulations are also applied to analyze the above experimental achievements, proving that different exposed facets of crystalline anodes possess dissimilar Na+ storage kinetics. The investigation experiences and conclusions shown in this work are meaningful to explore many other proper structure design routes toward the high-rate and stable metal-ions storage.

Controllable Design of MoS2 Nanosheets Anchored on Nitrogen-Doped Graphene: Toward Fast Sodium Storage by Tunable Pseudocapacitance.

Transition-metal disulfide with its layered structure is regarded as a kind of promising host material for sodium insertion, and intensely investigated for sodium-ion batteries. In this work, a simple solvothermal method to synthesize a series of MoS2 nanosheets@nitrogen-doped graphene composites is developed. This newly designed recipe of raw materials and solvents leads the success of tuning size, number of layers, and interplanar spacing of the as-prepared MoS2 nanosheets. Under cut-off voltage and based on an intercalation mechanism, the ultrasmall MoS2 nanosheets@nitrogen-doped graphene composite exhibits more preferable cycling and rate performance compared to few-/dozens-layered MoS2 nanosheets@nitrogen-doped graphene, as well as many other reported insertion-type anode materials. Last, detailed kinetics analysis and density functional theory calculation are also employed to explain the Na+ - storage behavior, thus proving the significance in surface-controlled pseudocapacitance contribution at the high rate. Furthermore, this work offers some meaningful preparation and investigation experiences for designing electrode materials for commercial sodium-ion batteries with favorable performance.

Quantum Chemical Insight into La2C96: Metal Carbide Fullerene La2C2@C94 versus Dimetallofullerene La2@C96.

A family of dilanthanum-containing endohedral metallofullerene La2C2n (n = 46-51) was synthesized recently. In the present work, a systematical investigation on La2C96 series including the carbide clusterfullerene form La2C2@C94 and the conventional dimetallofullerene form La2@C96 was implemented by density functional theory, combined with statistical mechanics. Three isomers, i.e., La2@D2(191838)-C96, La2C2@Cs(153479)-C94, and La2C2@C1(153491)-C94 were disclosed to be thermodynamically stable at the temperature region of endohedral metallofullerene formation. La2@D2(191838)-C96 is the prevailing isomer at low temperature, while La2C2@Cs(153479)-C94 and La2C2@C1(153491)-C94 are the most and second-most abundant isomers at high temperature. Interestingly, the highest occupied molecular orbital (HOMO) of La2C2@C1(153491)-C94 is distributed on one pole of the cage, and the lowest unoccupied molecular orbital (LUMO) of this isomer is mainly located on the equator of the cage, which can facilitate synthesis of regioselective derivatives. This work will provide useful information for further experimental identification and application of La2C96.

Van Der Waals heterogeneous layer-layer carbon nanostructures involving π···H-C-C-H···π···H-C-C-H stacking based on graphene and graphane sheets.

Noncovalent interactions involving aromatic rings, such as π···π stacking, CH···π are very essential for supramolecular carbon nanostructures. Graphite is a typical homogenous carbon matter based on π···π stacking of graphene sheets. Even in systems not involving aromatic groups, the stability of diamondoid dimer and layer-layer graphane dimer originates from C - H···H - C noncovalent interaction. In this article, the structures and properties of novel heterogeneous layer-layer carbon-nanostructures involving π···H-C-C-H···π···H-C-C-H stacking based on [n]-graphane and [n]-graphene and their derivatives are theoretically investigated for n = 16-54 using dispersion corrected density functional theory B3LYP-D3 method. Energy decomposition analysis shows that dispersion interaction is the most important for the stabilization of both double- and multi-layer-layer [n]-graphane@graphene. Binding energy between graphane and graphene sheets shows that there is a distinct additive nature of CH···π interaction. For comparison and simplicity, the concept of H-H bond energy equivalent number of carbon atoms (noted as NHEQ), is used to describe the strength of these noncovalent interactions. The NHEQ of the graphene dimers, graphane dimers, and double-layered graphane@graphene are 103, 143, and 110, indicating that the strength of C-H···π interaction is close to that of π···π and much stronger than that of C-H···H-C in large size systems. Additionally, frontier molecular orbital, electron density difference and visualized noncovalent interaction regions are discussed for deeply understanding the nature of the C-H···π stacking interaction in construction of heterogeneous layer-layer graphane@graphene structures. We hope that the present study would be helpful for creations of new functional supramolecular materials based on graphane and graphene carbon nano-structures. © 2017 Wiley Periodicals, Inc.

Tuning of the photoluminescence and up-conversion photoluminescence properties of single-walled carbon nanotubes by chemical functionalization.

Single-walled carbon nanotubes (SWNTs) were subjected to alkylation using alkyl bromide and alkyl dibromide, and the photoluminescence (PL) properties of the resulting alkylated SWNTs were characterized. Two new PL peaks were observed along with the intrinsic PL peak at 976 nm when alkyl bromide was used (SWNT-Bu: ∼1095 and 1230 nm, SWNT-Bn: 1104 and 1197 nm). In contrast, the use of α,α'-dibromo-o-xylene as an alkyl dibromide primarily resulted in only one new PL peak, which was observed at 1231 nm. The results revealed that the Stokes shift of the new peaks was strongly influenced by the addition patterns of the substituents. In addition, the time-resolved PL decay profiles of the alkylated SWNTs revealed that the PL peaks possessing a larger Stokes shift had longer exciton lifetimes. The up-conversion PL (UCPL) intensity of the alkylated SWNTs at excitation wavelengths of 1100 and 1250 nm was estimated to be ∼2.38 and ∼2.35 times higher than that of the as-dispersed SWNTs, respectively.

Single Step Stone-Wales Transformation Linking Two Thermodynamically Stable Sc2O@C78 Isomers.

Among the very recently reported dimetallic oxide fullerenes Sc2O@C2n (n = 35-47), a representative Sc2O@C78 still lacks of further characterizations. Herein, a systematical investigation on Sc2O@C78 has been performed by density functional theory combined with statistical thermodynamic studies. Two isolated pentagon rule (IPR) satisfying isomers, Sc2O@D3h(24109)-C78 and Sc2O@C2v(24107)-C78, are disclosed to possess prominent thermodynamic stabilities at the temperature region of fullerene formation. Significantly, these two structures are related by a single Stone-Wales transformation. Moreover, bonding critical points, bond orders, and delocalization indices have been analyzed to uncover covalent interactions in both isomers. In addition, (13)C NMR spectra and UV-vis-NIR adsorptions of the two stable structures are introduced to assist experimental identification and characterization in the future.

Deciphering the underlying mechanisms of oxidation-state dependent cytotoxicity of graphene oxide on mammalian cells.

The promising broad applications of graphene oxide (GO) derivatives in biomedicine have raised concerns about their safety on biological organisms. However, correlations between the physicochemical properties, especially oxidation degree of GOs and their toxicity, and the underlying mechanisms are not well understood. Herein, we evaluated the cytotoxicity of three GO samples with various oxidation degrees on mouse embryo fibroblasts (MEFs). Three samples can be internalized by MEFs observed via transmission electron microscopy (TEM), and were well tolerant by MEFs at lower doses (below 25µg/ml) but significantly toxic at 50 and 100µg/ml via Cytell Imaging System. More importantly, as the oxidation degree decreased, GO derivatives led to a higher degree of cytotoxicity and apoptosis. Meanwhile, three GOs stimulated dramatic enhancement in reactive oxygen species (ROS) production in MEFs, where the less oxidized GO produced a higher level of ROS, suggesting the major role of oxidative stress in the oxidation-degree dependent toxicity of GOs. Results from electron spin resonance (ESR) spectrometry showed a strong association of the lower oxidation degree of GOs with their stronger indirect oxidative damage through facilitating H2O2 decomposition into OH and higher direct oxidative abilities on cells. The theoretical simulation revealed the key contributions of carboxyl groups and aromatic domain size of nanosheets to varying the energy barrier of H2O2 decomposition reaction. These systematic explorations in the chemical mechanisms unravel the key physicochemical properties that would lead to the diverse toxic profiles of the GO nanosheets with different oxygenation levels, and offer us new clues in the molecular design of carbon nanomaterials for their safe applications in biomedicine.

Molecular-level insights into intrinsic peroxidase-like activity of nanocarbon oxides.

Nanocarbon oxides have been proved to possess great peroxidase-like activity, catalyzing the oxidation of many peroxidase substrates, such as 3,3',5,5'-tetramethylbenzidine (TMB) and o-phenylenediamine dihydrochloride (OPD), accompanied by a significant color change. This chromogenic reaction is widely used to detect glucose and occult blood. The chromogenic reaction was intensively investigated with density functional theory and molecular-level insights into the nature of peroxidase-like activity were gained. A radical mechanism was unraveled and the carboxyl groups of nanocarbon oxides were identified as the reactive sites. Aromatic domains connected with the carboxyl groups were critical to the peroxidase-like activity.