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The incomplete understanding of electron correlation is still profound due to the lack of exact solutions of the Schrödinger equation of many electron systems. In this work, we present the correlation-induced changes in the calculated many-electron systems beyond the standard residual. To locate the minimum of the Rayleigh quotient, each iteration is to seek the lowest eigenpairs in a subspace spanned by the current wave function and its gradient of the Rayleigh-quotient as well as the upcoming higher-order residual. Consequently, as the upcoming errors can be introduced and circumvented with the search in the higher-order residual, a concomitant improved performance in terms of number of iterations, convergence rate, and total elapsed time is very significant. The correlation energy components obtained with the original residual are corrected with the higher-order residual application, satisfying the correlation virial theorem with much improved accuracy. The comparison with the original residual, the higher-order residual significantly improves the electron binding, favoring the localization of electrons' distribution, revealed with the increasing peak of the distribution and correlation function and the reduced interelectron distance and its angle. [ABSTRACT FROM AUTHOR]

Investigating CO2RR on diamond and doped diamond surfaces: Highlighting initial protonation's key role and the remarkable catalytic efficiency of BN surfaces. [Display omitted] • B, N co-doped diamonds boost CO2RR performance. • Key intermediates, OCHO* and COOH* critically influences C1 products. • The OCHO* key intermediates gives HCOOH whereas COOH* favors CH 2 O, CH 3 OH, and CH 4. • BN surfaces efficiently produce HCOOH production without applied overpotentials. • BN diamonds exhibited pronounced selectivity favor CO2RR over hydrogen evolution. We employed Periodic Density Functional Theory (DFT) to investigate the catalytic activity of single and double dopant of boron (B), nitrogen (N), and phosphorous (P) anchored on diamond surfaces for the CO 2 reduction reaction (CO2RR) by analyzing reaction energy profiles. Our findings show that the double-doped catalyst exhibits lower energy barriers in CO2RR compared to the single dopants. Specifically, when considering BB and NN configurations, there is a thermodynamic preference towards the formation of formic acid (HCOOH) with overpotentials of 0.40 and 0.09 V, respectively. The co-doped catalyst comprising B and N (BN) demonstrates a tendency towards the formation of HCOOH without requiring any applied overpotentials. Notably, BN outperforms other catalysts, occupying the top position on the volcano plot, indicating the lowest limiting potential (U L), remarkable thermal stability, and the ability to suppress the competing hydrogen evolution reaction (HER). This research provides valuable insights into the product differentiation in the electroreduction of CO 2. [ABSTRACT FROM AUTHOR]

Background: The prevalence of stress urinary incontinence (SUI) in adult female in Taiyuan and what are the related risk factors are not clear. The aim of this study was to provide a basis for exploring the prevention and treatment of SUI in adult female in Taiyuan.Methods: A voluntary online questionnaire was used to investigate adult female in the community and surrounding townships of Taiyuan. Most of the questionnaires refer to the International Consultation on Incontinence Questionnaire-Female Lower Urinary Tract Symptoms, and adapt to the specific circumstances of the region. Data were analyzed using SPSS software (version 22.0).Results: A total of 4004 eligible questionnaires were obtained. The prevalence of SUI in adult female in Taiyuan was 33.5%. Univariate analysis and multivariate logistic regression analysis showed that place of residence, smoking, body mass index, diet, number of deliveries, mode of delivery, dystocia, menopause, oral contraceptives, urinary tract infection, making the bladder empty faster by pushing down and holding urine were risk factors for adult female stress urinary incontinence in Taiyuan.Conclusion: The prevalence of SUI in adult female in Taiyuan was high, and based on risk factors identified in this survey, population-level intervention strategies should be developed for the prevention and treatment of adult female SUI in Taiyuan. [ABSTRACT FROM AUTHOR]

Aiming to develop an effective catalytic process for utilizing biomass, conversion of corncob into furfural was firstly performed using tin-loaded bentonite (Sn-BTN) as solid acid catalyst. Corncob was pretreated with Sn-BTN (3.5 wt%) for producing furfural at 53.3% yield in methyl isobutyl ketone-water (5:5, v:v; pH 1.0) biphasic media within 0.5 h at 170 °C. Furthermore, an efficient Sn-BTN recycling was achieved after 5 cycles of repeated use. Finally, furoic acid was obtained at 53.3% yield from corncob via sequential catalysis with solid acid Sn-BTN and Brevibacterium lutescens whole cells harboring furfural-oxidizing activity in methyl isobutyl ketone-H2O (5:5, v:v) media was developed under the relatively mild conditions. Clearly, this hybrid strategy for the synthesis of furoic acid from biomass was successfully developed via tandem catalysis of corncob with Tin-loaded bentonite and Brevibacterium lutescens whole-cell. [ABSTRACT FROM AUTHOR]

Molecular structures that permit intramolecular rotational motion have the potential to function as molecular rotors. We have employed density functional theory and vibrational frequency analysis to study the characteristic structure and vibrational behavior of the molecule (4′,4″″-(bicyclo[2,2,2]octane-1,4-diyldi-4,1-phenylene)-bis-2,2′:6′,2″-terpyridine. IR active vibrational modes were found that favor intramolecular rotation. To demonstrate the rotor behavior of the isolated single molecule, ab initio molecular dynamics simulations at various temperatures were carried out. This molecular rotor is expected to be thermally triggered via excitation of specific vibrational modes, which implies randomness in its direction of rotation. [ABSTRACT FROM AUTHOR]

Intermolecular interactions, in regard to which people tend to emphasise the noncovalent van der Waals (vdW) forces when conducting investigations throughout chemistry, can influence the structure, stability and function of molecules and materials. Despite the ubiquitous nature of vdW interactions, a simplified electrostatic model has been popularly adopted to explain common intermolecular interactions, especially those existing in π-involved systems. However, this classical model has come under fire in revealing specific issues such as substituent effects, due to its roughness; and it has been followed in past decades by sundry explanations which sometimes bring in nebulous descriptions. In this account, we try to summarise and present a unified model for describing and analysing the binding mechanism of such systems from the viewpoint of energy decomposition. We also emphasise a commonly ignored factor - orbital interaction, pointing out that the noncovalent intermolecular orbital interactions actually exhibit similar bonding and antibonding phenomena as those in covalent bonds. [ABSTRACT FROM AUTHOR]

We report an efficient and consistent method for the solution of Schrödinger wave equation using the Green's function technique and its successful application to the nonrelativistic radial wave equation of hydrogen atom. For the radial wave equation, the Green's function is worked out analytically by means of Laplace transform method and the wave function is proposed under the boundary conditions. Computationally the product of potential term, the proposed wave function and the Green's function are integrated iteratively to get the nonrelativistic radial wave function. The resultant wave after each iteration is normalized and plotted against the standard nonrelativistic radial wave function. The solution converges to the standard wave with the increasing number of iterations. Results are verified for the first 15 states of hydrogen atom. The method adopted here can be extended to many-body problem and hope that it can enhance our knowledge about complex systems. [ABSTRACT FROM AUTHOR]

The catalytic decomposition of formic acid (HCOOH) is a crucial process for hydrogen production technologies. Herein, periodic density functional theory (DFT) calculations were employed to explore the effect of N-doping on the decomposition of formic acid. We designed a series of single Pd-atoms deposited in the single vacancy of N-doped graphene sheets, namely Pd-DGr, Pd–N1Gr, Pd–N2Gr, and Pd–N3Gr, as the proposed catalysts. Our findings show that H 2 production from HCOOH dehydrogenation on these surfaces proceeds via the formate (HCOO) pathway (Path-I) rather than the carboxylate (COOH) pathway (Path-II). Furthermore, the Pd–N3Gr catalyst shows the greatest catalytic reactivity toward HCOOH dehydrogenation via Path-I , requiring an activation energy (E a) of 0.38 eV. On the other hand, the undesirable dehydration of HCOOH to carbon monoxide (CO) through COOH (Path-IIIA) or formyl (HCO) (Path-IIIB) intermediates is unlikely to occur on Pd–N3Gr due to a large activation energy. We found that the active species on the catalyst surface increased with N-doping concentration. Additionally, microkinetic simulations of the HCOOH decomposition on these surfaces confirmed the high activity and selectivity of the Pd–N3Gr catalyst toward HCOOH dehydrogenation (Path-I). These calculated results highlight that the Pd–N3Gr catalyst is a promising candidate for the formic acid decomposition reaction to yield hydrogen. The pyridinic- N atom at the graphene surface play important role in catalytic activity, The Pd–N3Gr catalyst with optimal 3 pyridinic N atoms shows the best performance (compared to N > 3 and N < 3). [Display omitted] • The pyridinic-N atoms at the graphene play important role in catalytic activity. • The optimal 3 pyridinic N atoms shows the best performance compared to N > 3 and N < 3. • Formic dehydrogenation on Pd–N3Gr require remarkably low energy barrier of 0.38 eV. • Formic dehydrogenation on Pd–N3Gr exhibit excellent selectivity toward H 2 production. • Pd–N3Gr is potentially an efficient and low-cost single atom catalyst for formic dehydrogenation. [ABSTRACT FROM AUTHOR]

In this article, we review a practical and effective scheme proposed by one of the authors for choosing basis sets in ab initio calculations and assess its efficiency in selected applications. In the scheme, we consider the different roles of the particular functions, including the polarization and diffuse functions, adopted in the basis set, as well as the nature and environment of the atom. The number and level of basis functions required to describe an atom should be determined according to its relative order in the periodic table and/or electronegativity. For an atom with a relatively higher electronegativity, larger basis functions including polarization and diffuse functions should be used, while the basis functions for a less electronegative atom or positively charged atom can be reduced and may not adopt any polarization and diffuse functions. For systems involving hydrogen bonding, weak interactions, functional groups, metallic bonding with zero or low-positive valence, and other sensitive interactions, both the polarization and diffuse functions may need to be used. These economical composite basis sets are applied to a variety of systems, from small to very large compounds. Compared with the calculations required for conventional basis set schemes at different levels, the economical composite basis set can accurately predict the structures and properties of compounds while saving significant CPU. A single-point calculation using the geometric structure determined using the economical composite basis set can further improve the accuracy of calculating certain properties. © 2014 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

In this review, we outline our computational efforts in understanding the interactions between water and various graphitic carbon surfaces based on quantum-mechanical level calculations. Among them, we have determined the geometry structures, electronic properties, and vibrational infrared and resonant Raman spectra of water clusters on graphene surface and single walled carbon nanotubes (SWCNTs). Specifically, we found that (1) the hexamer water cluster undergoes isomerization when interacting with a graphene surface, while the smaller water clusters maintain their cyclic or linear configurations, with little changes in their infrared peak positions and almost perfect graphene surfaces due to the physical adsorption of the water clusters; and (2) water molecules can form cylindrical crystalline structures, referred to as ice nanotubes, by hydrogen bonding under confinement within SWCNTs. Our computational results are expected to shed light on the graphene and SWCNTs studies and their applications in areas such as biology and materials science. [ABSTRACT FROM AUTHOR]

An introduction is presented in which the editor discusses various reports published within the issue which include the clusters on surfaces, the chemical and catalytic reactivities, and the reactions of molecules or radicals on the interior surface of clusters.

Cancer‐derived exosomes are involved in the development of cancer cachexia. Carnosol, which exhibited ameliorating effects on cancer cachexia of C26 tumour‐bearing mice in our previous study, alleviated atrophy of C2C12 myotubes induced by exosomes of C26 tumour cells in the present study. MiR‐183‐5p was found to be rich in C26 cells and C26 exosomes, and miR‐183‐5p mimic could directly induce atrophy of C2C12 myotubes. Carnosol at 5 to 20 μM could dose‐dependently ameliorate the myotube atrophy induced by miR‐183‐5p. Four and a half LIM domain protein 1 (FHL1) was shown to be the direct target of miR‐183‐5p. Increase in myostatin, p‐Smad3, MuRF‐1, Atrogin‐1, HIF‐1α and p‐STAT3 and decrease in mitochondrial respiration were also induced by miR‐183‐5p mimic in C2C12 myotubes. Carnosol could not affect the decrease in FHL‐1 and the activation of STAT3 pathway but could significantly alleviate the increase in myostatin, p‐Smad3, MuRF‐1, Atrogin‐1 and the decrease in mitochondrial respiration induced by miR‐183‐5p. The protective effects of carnosol on myotubes against atrophy of C2C12 myotubes induced by miR‐183‐5p, based on both its inhibiting effects on MuRF‐1 and Atrogin‐1‐mediated protein degradation and its ability of keeping the mitochondrial respiration, might contribute to its ameliorating effects on cancer cachexia. [ABSTRACT FROM AUTHOR]

An error appeared in our paper entitled "Enhanced Biosynthesis of Furoic Acid via the Effective Pretreatment of Corncob into Furfural in the Biphasic Media" published in Catalysis Letters. Unfortunately, there are some mistakes in the values and equation in the Sect. 2.3 Conversion of Corncob to FAL and in Table 2. [ABSTRACT FROM AUTHOR]

Abstract: Arbuscular mycorrhizal fungi can increase the host resistance to pathogens via promoted phenolic synthesis, however, the signaling pathway responsible for it still remains unclear. In this study, in order to reveal the signaling molecules involved in this process, we inoculated Trifolium repense L. with an arbuscular mycorrhizal fungus (AMF), Glomus mosseae, and monitored the contents of phenolics and signaling molecules (hydrogen peroxide (H2O2), salicylic acid (SA), and nitric oxide (NO)) in roots, measured the activities of l-phenylalanine ammonia-lyase (PAL) and nitric oxide synthase (NOS), and the expression of pal and chs genes. Results demonstrated that AMF colonization promoted the phenolic synthesis, in parallel with the increase in related enzyme activity and gene expression. Meanwhile, the accumulation of all three signaling molecules was also up-regulated by AMF. This study suggested that AMF increased the phenolic synthesis in roots probably via signaling pathways of H2O2, SA and NO in a signaling cascade. [Copyright &y& Elsevier]

We propose a possible approach for controlled formation of various 585 (containing pentagonal and octagonal carbon rings) extended line defects (ELDs) by linear adsorption of various kinds of atoms (C, N, B, O) on a graphene substrate, based upon density functional theory and molecular-dynamics (MD) simulations. We find out that the C and N atoms spontaneously transform to 585 ELDs while other elements find specific stable configurations. To confirm the feasibility of forming the ELD from line adsorption, investigation of the critical transformation conditions of the 585 ELD is involved based upon various adsorption models and adsorption densities. [ABSTRACT FROM AUTHOR]

Li‐rich antiperovskite (LiRAP) hydroxyhalides are emerging as attractive solid electrolyte (SEs) for all‐solid‐state Li metal batteries (ASSLMBs) due to their low melting point, low cost, and ease of scaling‐up. The incorporation of rotational polyanions can reduce the activation energy and thus improve the Li ion conductivity of SEs. Herein, we propose a ternary rotational polyanion coupling strategy to fasten the Li ion conduction in tetrafluoroborate (BF4−) ion doped LiRAP Li2OHCl. Assisted by first‐principles calculation, powder X‐ray diffraction, solid‐state magnetic resonance and electrochemical impedance spectra, it is confirmed that Li ion transport in BF4− ion doped Li2OHCl is strongly associated with the rotational coupling among OH−, BF4− and Li2−O−H octahedrons, which enhances the Li ion conductivity for more than 1.8 times with the activation energy lowering 0.03 eV. This work provides a new perspective to design high‐performance superionic conductors with multi‐polyanions. [ABSTRACT FROM AUTHOR]

Li‐rich antiperovskite (LiRAP) hydroxyhalides are emerging as attractive solid electrolyte (SEs) for all‐solid‐state Li metal batteries (ASSLMBs) due to their low melting point, low cost, and ease of scaling‐up. The incorporation of rotational polyanions can reduce the activation energy and thus improve the Li ion conductivity of SEs. Herein, we propose a ternary rotational polyanion coupling strategy to fasten the Li ion conduction in tetrafluoroborate (BF4−) ion doped LiRAP Li2OHCl. Assisted by first‐principles calculation, powder X‐ray diffraction, solid‐state magnetic resonance and electrochemical impedance spectra, it is confirmed that Li ion transport in BF4− ion doped Li2OHCl is strongly associated with the rotational coupling among OH−, BF4− and Li2−O−H octahedrons, which enhances the Li ion conductivity for more than 1.8 times with the activation energy lowering 0.03 eV. This work provides a new perspective to design high‐performance superionic conductors with multi‐polyanions. [ABSTRACT FROM AUTHOR]

P and N co-doped graphene (PNxCy-G with x = 1, 2, 3 and y = 0, 1, 2) is designed to enhance graphene reactivity with a synergistic effect of the P and N atoms for the CO oxidation reaction, focusing on the influence of the N dopant concentration on graphene. The calculated results indicate that increasing two or three coordinated N to P can facilitate charge transfer from the surface onto O2 molecules. However, the adsorbed O2 molecule breaks apart on PN3-G surface, affecting CO oxidation performance. Furthermore, PN2C1-G exhibits excellent catalytic activity towards the oxidation of CO via the ER mechanism, which catalyzes CO oxidation with the rate-determining step of only 0.26 eV for the first and 0.25 eV for the second oxidation at 0 K. Additionally, the catalytic oxidation of PN2C1-G via Eley–Rideal mechanism prefers to occur at room temperature (298.15 K), with a rate-determining step of 0.77 eV. The reaction rates at 298.15 K is calculated to be 5.36 × 1016 mol s–1. The rate constants are obtained according to harmonic transition state theory, which could be supportive for catalytic oxidation of CO on the experiment. [ABSTRACT FROM AUTHOR]

Abstract: Three new carbon allotropes have been uncovered by compressing hexagonal C20 solid based on density functional tight binding level simulations. They are identified to be energetically more favorable and stable than C20 molecule, with the phase III structure being the energetically most favorable. The volume compression calculations suggest that the phase III has a very high anti-compressibility with a bulk modulus of 427GPa. All of the predicted structures are semiconductors with varied bandgaps and the phase III has a direct band gap of 5.1eV. Our results indicate that solid C20 can be converted to a transparent superhard material under cold compression. [Copyright &y& Elsevier]

Distinctive from conventional electronic structure methods, we solve the Schrödinger wave equations of the helium atom and its isoelectronic ions by employing one-dimensional basis functions to separate components. We use full two-electron six-dimensional operators and wavefunctions represented with real-space grids where the refinement of the latter is carried out using a residual minimization method. In contrast to the standard single-electron approach, the current approach results in exact treatment of repulsion energy and, hence, more accurate electron correlation within five centihartrees or better included, with moderate computational cost. A simple numerical convergence between the error to accurate results and the grid-spacing size is found. The obtained two-electron Schrödinger wavefunction that contains vast and elaborating information for the radial correlation function and common one-dimensional functions shows the electron correlation effect on one-electron distributions. [ABSTRACT FROM AUTHOR]

Construction of BVO ac -BVO al homojunction without incorporating other heteroatoms promoted an increase of photocurrent density to 3.6 mA/cm2 at 1.23 V vs. the reversible hydrogen electrode with 0.1 M sodium sulfite as the hole scavenger under the illumination. [Display omitted] The photoelectrochemical (PEC) performance of bismuth vanadate (BiVO 4) suffers from sluggish charge mobility and substantial charge recombination losses due to its intrinsic defect. To rectify the problem, we developed a novel approach to prepare an n - n + type II BVO ac -BVO al homojunction with staggered band alignment. This architecture involves a built-in electric field that facilitating the electron-hole separation at the BVO ac /BVO al interface. As a result, the BVO ac -BVO al homojunction shows superior photocurrent density up to 3.6 mA/cm2 at 1.23 V vs. reversible hydrogen electrode (RHE) with 0.1 M sodium sulfite as the hole scavenger, which is 3 times higher than that of the single-layer BiVO 4 photoanode. Unlike the previous efforts that modifying the PEC performance of BiVO 4 photoanodes through incorporating heteroatoms, the highly-efficient BVO ac -BVO al homojunction was achieved without incorporating any heteroatoms in this work. The remarkable PEC activity of the BVO ac -BVO al homojunction highlights the tremendous importance of reducing the charge recombination rate at the interface by constructing the homojunction and offers an effective strategy to form the heteroatoms-free BiVO 4 thin film as an efficient photoanode material for practical PEC applications. [ABSTRACT FROM AUTHOR]

Podocyte damage is the initial hallmark of diabetic nephropathy (DN), leading to the increasing morbidity and mortality in diabetic patients. Recent researches have corroborated the critical roles of miRNAs in the pathological progression of DN. Here, elevation of miR-217 was verified in high glucose (HG)-stimulated podocytes. Moreover, blocking miR-217 expression antagonized HG-induced cell injury by attenuating the adverse role of HG on cell viability and inhibiting ROS levels and cell apoptosis. Simultaneously, miR-217 repression restored HG-disrupted insulin resistance by elevating glucose uptake and nephrin expression, an essential component for insulin-induced glucose uptake. Mechanism assay substantiated the defective autophagy in HG-treated podocytes, which was resumed by miR-217 cessation. Importantly, suppressing autophagy pathway with 3-MA alleviated the protective roles of miR-217 down-regulation in podocyte injury and insulin resistance. Luciferase reporter analysis confirmed that PTEN was a target of miR-217 in podocytes. Additionally, blocking PTEN expression restrained autophagy restoration in miR-217-decreased cells. Furthermore, PTEN down-regulation attenuated the beneficial role of miR-217 suppression in HG-induced injury and insulin resistance. Together, this study manifests that miR-217inhibition can protectively antagonize HG-induced podocyte damage and insulin resistance by restoring the defective autophagy pathway via targeting PTEN, representing a novel and promising therapeutic target against diabetic nephropathy. [ABSTRACT FROM AUTHOR]

Graphitic carbon nitride (g-CN), as an orderly structured polymer derivative, has been widely concerned for its photocatalytic ability due to its metal-free nature and unique properties. However, the photoelectrochemical (PEC) application of g-CN is still hindered by the difficulty of forming high-quality films with good uniformity and crystallinity. Herein, we studied the rapid thermal vapor condensation (RTVC) for growing g-CN films with improved PEC activity. The polycondensation and polymerization reactions of precursor melamine molecules under the optimized temperature 600 °C and calcination time 20 min resulted in better crystallinity of g-CN films. Remarkably, the growth of g-CN film based on the coalescence of unambiguous hexagonal nanosheets was observed, as corroborated by scanning electron microscopy and transmission electron microscopy. This novel RTVC method offers a fast and easy strategy for improving the crystallinity of g-CN films through controlling the thermal dynamics and kinetics of film growth from temperature and time. [ABSTRACT FROM AUTHOR]

The energetically favorable structures and characteristic infrared (IR) and Raman peaks of TinOm (n = 2--4, m<2n) clusters are obtained in this work using a B3LYP/6-311G(d) method of density functional theory (DFT). The structures with m < 2n compose of Ti atoms of lower numbers of coordination with O atoms, providing many dangling bonds which con-siderably enhance the reactivity compared with its bulk counterpart. Two- and three-coordi-nated O atoms present for m/n < 1.5, whereas two- and also single-coordinated O atoms are found for m/n > 1.5. The TinOm (n = 2--4, m < 2n) clusters show strong IR peaks in the range of 600-1100 cm-1 and strong Raman peaks in the region of 300-800 cm-1, whereas both the IR and Raman spectrum peaks of the TinOm (n = 2--4, m = 2n) clusters are in the region of 700--1100cm-1. The main Raman peak of the TinOm (m ≠ 2n) clusters is at a frequency considerably lower than that of the IR spectrum. Our results can help understand the structure-property relationships of the TinOm clusters and provide their characteristic spectroscope features for further experimental identification. [ABSTRACT FROM AUTHOR]

The adsorption of buckminsterfullerene (C) on metal surfaces has been investigated extensively for its unique geometric and electronic properties. The two-dimensional systems formed on surfaces allow studying in detail the interplay between bonding and electronic structures. Recent studies reveal that C adsorption induces reconstruction of even the less-reactive close-packed metal surfaces. First-principles computations enable access to this important issue by providing not only detailed atomic structure but also electronic properties of the substrate-adsorbate interaction, which can be compared with various experimental techniques to determine and understand the interface structures. This review discusses in detail the ordered phases of C monolayers on metal surfaces and the surface reconstruction induced by C adsorption, with an emphasis on the different types of reconstruction resulting on close-packed metal surfaces. We show that the symmetry matching between C molecules and metal surfaces determines the local adsorption configurations, while the size matching between C molecules and the metal surface lattice determines the supercell sizes and shapes; importantly and uniquely for C, the number of surface metal atoms within one supercell determines the different types of reconstruction that can occur. The atomic structure at the molecule-metal interface is of crucial importance for the monolayer's electronic and transport properties: these will also be discussed for the well-defined adsorption structures, especially from the perspective of tuning the electronic structure via C-metal interface reconstruction and via relative inter-C orientations. [ABSTRACT FROM AUTHOR]

Measurement of the four relevant radioxenon isotopes, namely 131m Xe, 133m Xe, 133Xe, and 135Xe, play a key role in underground nuclear explosion monitoring for ensuring compliance with the Comprehensive Nuclear-Test-Ban Treaty (CTBT). A β - γ coincidence system that employs a plastic scintillator detector and a HPGe detector was developed in Beijing Radionuclide Laboratory. The Minimum Detectable Activity (MDA) in a 24-h measurement of the system for 131m Xe, 133m Xe, 133Xe and 135Xe can achieve 1.8 mBq, 1.4 mBq, 3.4 mBq and 4.1 mBq, respectively. [ABSTRACT FROM AUTHOR]

Highlights • The unusual ClAlPc molecular self-assembled layer on a buffer layer have large deformations compared with the common ClAlPc bilayer. • Almost freestanding environment is provided for the molecules when the influence from the substrate is shielded by the buffer layer. • The dominated intermolecular interaction is likely to be the dispersion forces via Reduced Density Gradient analysis. Abstract We report an unusual self-assembled layer structure of chloroaluminium phthalocyanine (ClAlPc) molecules on highly ordered pyrolytic graphite (HOPG), in which a close-packed well-ordered monolayer is separated from the substrate by a relatively disordered buffer layer, as revealed using scanning tunneling microscopy (STM). Our close-packed monolayer has a nearly rectangular lattice, instead of the distinctly different square lattice for the more commonly observed well-ordered bilayer structure. This may be due to the dominance of intermolecular interactions within the monolayer when the influence from the substrate is shielded by the buffer layer. Density Functional Theory (DFT) calculations and Reduced Density Gradient (RDG) analysis indicate that the dominant intermolecular interaction within the unusual layer is likely the London dispersion force. Graphic abstract Image, graphical abstract [ABSTRACT FROM AUTHOR]

Highlights • Showing substrate-mediated and temperature-modulated effects of Br stripes on Cu(1 1 1) • Explaining the formation mechanism of adsorbate diversities for STM experiments. • Successful calculations in nanoscale models by first-principles MD simulations. Abstract Understanding long-range adsorbate-adsorbate interactions on surfaces, such as halogens on metal surfaces, is important in the fields of electrochemistry, catalysis, and thin film growth. In this work, we computationally studied bromine (Br) stripe formations on Cu(1 1 1). These stripes are found to be surface-mediated and temperature-modulated; they are facilitated by Br Cu bonding guided by self-patterning of Cu(1 1 1) surface frontier orbitals and by strain release induced stripe migration in a thermal bath. The calculated surface wave-functions in frontier occupied states show stripe-like electron distributions and thus the favorable sites of Br adsorption on Cu(1 1 1) are also stripe-like. The temperature effect is notable in that the thermal energy of 50 K easily dominates Br stripe gathering in (√3×√3)R30° structures. Corresponding electron stripes on the surface could be generated, widened, shrunk or removed depending on spacing changes of Br stripes, thus reflecting diverse and changeable formation features for dynamic patterns of adsorbates on Cu(1 1 1). [ABSTRACT FROM AUTHOR]

Target-oriented photoelectrochemical (PEC) performance can be enabled by regulating the physicochemical properties of graphitic carbon nitride (CN)-based photoanodes in the PEC process. Herein, we introduced boron heteroatoms into CN films (BCN) and explored the influence of the B heteroatom on the PEC performance experimentally and theoretically. B atoms favor substitution of carbon atoms at bay sites in BCN films and reduce the bandgap by raising the valence band edge as well as constructing optimal electronic structures for PEC hydrogen production. The as-prepared BCN films exhibit nearly 4 times higher photocurrent density than that of pristine CN films. We demonstrate that such enhancement originates from the spatially complementary orbital distribution over the BCN films, thus expediting the charge carrier separation. This work proposes ideal empirical routines for multiple functionalization of CN films for diverse PEC activities via component tailored strategies. [ABSTRACT FROM AUTHOR]

Abstract: The solution of three‐dimensional Schrödinger wave equations of the hydrogen atoms and their isoelectronic ions (Z = 1 − 4) are obtained from the linear combination of one‐dimensional hydrogen wave functions. The use of one‐dimensional basis functions facilitates easy numerical integrations. An iteration technique is used to obtain accurate wave functions and energy levels. The obtained ground state energy level for the hydrogen atom converges stably to −0.498 a.u. The result shows that the novel approach is efficient for the three‐dimensional solution of the wave equation, extendable to the numerical solution of general many‐body problems, as has been demonstrated in this work with hydrogen anion. [ABSTRACT FROM AUTHOR]

Single-walled conjugated microporous polymer (CMP) nanotubes containing alternative phenylene and ethynylene units were described computationally for the first time in this work. The electronic structures and adsorption properties were studied by the density-functional tight-binding method augmented with a van der Waals dispersion term. Our calculations show that the morphology of CMP influences the benzene-adsorption performance significantly. The tubes show smaller binding energies to benzene molecule than the film counterparts, consistent with the observation of low adsorption capacities of tubular materials in our experiments. Enlarging the linker or adding substituents in the node can both reduce the tube's band gap. The introduction of OH or NH2 substituents in the tube node increases the binding strength between the adsorbent and the adsorbate, which is energetically favorable to enhance the adsorption capacity. Our results are expected to provide theoretical insights into the rational design of novel CMP nanotubes with improved adsorption capacities for organics. [ABSTRACT FROM AUTHOR]

We propose a new pathway for the adsorption of benzyl alcohol on the surface of TiO and the formation of interfacial surface complex (ISC). The reaction free energies and reaction kinetics were thoroughly investigated by density functional calculations. The TiO surfaces were modeled by clusters consisting of 4 Ti atoms and 18 O atoms passivated by H, OH group and HO molecules. Compared with solid-state calculations utilizing the periodicity of the materials, such cluster modeling allows inclusion of the high-order correlation effects that seem to be essential for the adsorption of organic molecules onto solid surfaces. The effects of both acidity and solvation are included in our calculations, which demonstrate that the new pathway is competitive with a previous pathway. The electronic structure calculations based on the relaxed ISC structures reveal that the chemisorption of benzyl alcohol on the TiO surface greatly alters the nature of the frontier molecular orbitals. The resulted reduced energy gap in ISC matches the energy of visible light, showing how the adsorption of benzyl alcohol sensitizes the TiO surface. [ABSTRACT FROM AUTHOR]

Applications of graphitic carbon nitride (g-CN) in photoelectrochemical and optoelectronic devices are still hindered due to the difficulties in synthesis of g-CN films with tunable chemical, physical and catalytic properties. Herein we present a general method to alter the electronic and photoelectrochemical properties of g-CN films by annealing. We found that N atoms can be removed from the g-CN networks after annealing treatment. Assisted by theoretical calculations, we confirm that upon appropriate N removal, the adjacent C atoms will form new C=C π bonds. Detailed calculations demonstrate that the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) are located at the structure unit with C=C π bonds and the electrons are more delocalized. Valence band X-ray photoelectron spectroscopy spectra together with optical absorption spectra unveil that the structure changes result in the alteration of the g-CN energy levels and position of band edges. Our results show that the photocurrent density of the annealed g-CN film is doubled compared with the pristine one, thanks to the better charge separation and transport within the film induced by the new C=C π bonds. An ultrathin TiO2 film (2.2 nm) is further deposited on the g-CN film as stabilizer and the photocurrent density is kept at 0.05 mA cm−2 at 1.23 V versus reversible hydrogen electrode after two-cycle stability assessment. This work enables the applications of g-CN films in many electronic and optoelectronic devices. [ABSTRACT FROM AUTHOR]

Study Objective: To compare the incidence of postoperative cognitive dysfunction (POCD) in elderly surgical patients (>60years) receiving different anesthetics (propofol, sevoflurane, or isoflurane) and to identify potential biomarkers of POCD in this patient population.Design: Prospective, randomized, double-blind clinical trial.Setting: University-affiliated teaching hospital.Patients: One hundred and fifty elderly patients scheduled for laparoscopic cholecystectomy.Interventions: Elderly patients undergoing laparoscopic cholecystectomy were randomly assigned to receive propofol, sevoflurane, or isoflurane anesthesia.Measurements: Cognitive function was assessed using neuropsychological tests at baseline (1day before surgery [D0]), and on postoperative day 1 (D1) and day 3 (D3). Plasma S-100β and Aβ1-40 protein, IL-1β, IL-6 and TNF-α concentrations were assessed before induction of anesthesia (T0), after extubation (T1), and 1h (T2) and 24h (T3) postoperatively.Main Results: The incidence of POCD was significantly lower in the propofol group compared to the isoflurane group and the sevoflurane group at D1 and D3 (propofol vs. isoflurane: D1 and D3, P<0.001; propofol vs. sevoflurane: D1, P=0.012; D3, P=0.013). The incidence of POCD was significantly lower in the sevoflurane group compared to the isoflurane group at D1 (P=0.041), but not at D3. Postoperatively, plasma S-100β and Aβ1-40 protein, IL-1β, IL-6, and TNF-α concentrations were significantly decreased in the propofol group compared to the isoflurane group.Conclusions: Propofol anesthesia may be an option for elderly surgical patients. [ABSTRACT FROM AUTHOR]

Active species such as holes, electrons, hydroxyl radicals ( OH), and superoxide radical anions ( O 2 − ) involved in the photocatalytic oxidation of benzyl alcohol (BA) into benzaldehyde (BAD) on TiO 2 under ultraviolet (UV) light were investigated by adding corresponding scavengers. The experimental results show that the oxidation of BA into BAD is driven mainly by the holes and OH radical. The role of dissolved O 2 was studied by bubbling N 2 through the reaction. The results show that the dissolved O 2 is, to some extent, the source of OH. Additional density functional theory (DFT) calculations identified two H-abstraction pathways ( R abs OH and R abs α). The structure of the R abs OH product is less stable and tends to transfer resulting in the R abs α product. The holes are the main driving force for the abstracting of H from BA. The OH radical combines with the H-abstract product to form a precursor of product BAD, detected by LC–MS technique ( m / z 123), which then undergoes an intramolecular dehydration reaction to form BAD. The results will help to select the optimal active species for the photocatalytic oxidation of BA into BAD on TiO 2 under UV light. [ABSTRACT FROM AUTHOR]

Iron-based catalysts have been demonstrated to activate peroxymonosulfate (PMS) to generate reactive radicals, which is however limited by their complex preparation process, high costs and inefficiency for practical applications. Herein we obtain spent LiFePO 4 (SLFP), with powerful catalytic capacity by a simple one-step treatment of the retired LiFePO 4 cathode material, for PMS activation to decontaminate organic pollutants. Lithium defects and oxygen vacancies in SLFP play critical roles for PMS utilization, further confirmed by density functional theory (DFT) calculations. SLFP materials rapidly adsorb PMS, and the surface PMS is activated by Fe(II) to generate radicals, with •OH playing a major role for the degradation of organics after multi-step reactions. The SLFP/PMS process is finally validated for ability to remove organic contaminants and potential environmental application. • SLFP was an old but vigorous PMS activator for decontamination. • Surface defects of SLFP play a key role in PMS activation. • Quenching experiment and DFT calculation were used to reveal mechanism. • This proposed SLFP/PMS process was environmental benign. [ABSTRACT FROM AUTHOR]

Review: 98 refs. [ABSTRACT FROM AUTHOR]

[Display omitted] • We propose a rejuvenation recipe for SLFP in applied environmental catalysis. • SLFP exhibits enhanced reactivity than pristine one in the activation of S(IV). • Li defects and oxygen vacancies are key to unexpected reactivity of SLFP. Lab-prepared Fe-bearing materials have demonstrated their ability to activate sulfite (S(IV)) to generate reactive radicals, which is however limited by their costs and inefficiencies for practical application. Here we report that spent LiFePO 4 (SLFP) cathode materials can function as a robust catalyst for S(IV) activation and consequent decontamination of organic pollutants like 4,4′-sulfonyldiphenol (BPS). Unexpectedly, SLFP materials with lithium defects and oxygen vacancies (O v) are significantly effective than pristine LiFePO 4. BPS degradation undergoes an induction period when rapid adsorption of O 2 and HSO 3 − in water occurs, followed by a slow release of HSO 5 −, as evidenced by the same depletion trends of BPS and sulfite, and confirmed by theoretical calculations. The HSO 5 − is activated by Fe(II) on the SLFP surface, with •OH being the main reactive species via a multi-step reaction. The potential environmental application of this SLFP/S(IV) process are evaluated ultimately. [ABSTRACT FROM AUTHOR]

[Display omitted] • We propose a rejuvenation recipe for SLFP in applied environmental catalysis. • SLFP exhibits enhanced reactivity than pristine one in the activation of S(IV). • Li defects and oxygen vacancies are key to unexpected reactivity of SLFP. Lab-prepared Fe-bearing materials have demonstrated their ability to activate sulfite (S(IV)) to generate reactive radicals, which is however limited by their costs and inefficiencies for practical application. Here we report that spent LiFePO 4 (SLFP) cathode materials can function as a robust catalyst for S(IV) activation and consequent decontamination of organic pollutants like 4,4′-sulfonyldiphenol (BPS). Unexpectedly, SLFP materials with lithium defects and oxygen vacancies (O v) are significantly effective than pristine LiFePO 4. BPS degradation undergoes an induction period when rapid adsorption of O 2 and HSO 3 − in water occurs, followed by a slow release of HSO 5 −, as evidenced by the same depletion trends of BPS and sulfite, and confirmed by theoretical calculations. The HSO 5 − is activated by Fe(II) on the SLFP surface, with •OH being the main reactive species via a multi-step reaction. The potential environmental application of this SLFP/S(IV) process are evaluated ultimately. [ABSTRACT FROM AUTHOR]

Uniform carbon nitride electrodes, with enhanced photoelectrochemical cell (PEC) performance, are successfully developed by clever design of monomers interaction at high temperatures using thermal vapor condensation method. The monomers alteration leads to a significant improvement of the optical, electronic, and PEC properties of the carbon nitride films, resulting in incident photon‐to‐current efficiency of 16% at 400 nm. [ABSTRACT FROM AUTHOR]

Direct synthesis of three-dimensional Ag structures on solid substrates for the purposes of producing reproducible and recyclable surface-enhanced Raman scattering (SERS) applications remains challenging. In this work, flower-like Ag structures with concave surfaces (FACS) were successfully electrodeposited onto ITO glass using the double-potentiostatic method. The FACS, with an enhancement factor of the order of 10 8 , exhibited a SERS signal intensity 3.3 times stronger than that measured from Ag nanostructures without concave surfaces. A cleaning procedure involving lengthy immersion of the sample in ethanol and KNO 3 was proposed to recycle the substrate and confirmed by using rhodamine 6G, adenine, and 4-aminothiophenol as target molecules. The findings can help to advance the practical applications of Ag nanostructure-based SERS substrates. [ABSTRACT FROM AUTHOR]

Electronic structures and related properties of a defective endohedral metallofullerene U2@C61-Def[5,6] are studied using density functional theory. It is shown that unlike the U2@C61-Def[6,6] which has a nonet ground state, the U2@C61-Def[5,6] has a quintet ground spin state with a lower total energy than the U2@C61-Def[6,6]. This is due to the antiferromagnetic coupling of the net spin electrons of the U2 unit with the net spin of both the cage and the adatom. Compared with the U2@C60, the [5,6]-type defect demonstrates almost no change in the energy gap, while the [6,6]-type defect does show a reduction. The electronic states and energy gaps of the endohedral metallofullerenes can therefore be engineered in a controllable manner by introducing different adatom-type defects. [ABSTRACT FROM AUTHOR]

First-principlescalculations based on density functional theory have been performedto explore the stable configurations, electronic structures, and vibrationalspectra of neutral and charged silicon monoxide clusters (SiO)n(0,±)(n= 2–7), which could be used as precursors in the synthesisof silicon nanowires. Our theoretical calculations provide new resultson characteristic electron affinity, ionization potential, and vibrationalspectroscopy, guiding future experiments in the synthesis of high-qualitysilicon nanowires. Specifically, as the number of SiO units nincreases, IR spectra of (SiO)n±and Raman spectra of (SiO)n–show an evident blue shift, and Raman spectraof (SiO)ndemonstrate a red shift. Moreover,most of the neutral silicon monoxide clusters have strong IR intensitiesand weak Raman activities, while most of the anionic counterpartshave relatively weak IR intensities and strong Raman activities. Someother energetically competitive isomers of some (SiO)n(0,±)species were also studied forcomparison. [ABSTRACT FROM AUTHOR]

Highlights: [•] A polarization function independent ground state (triplet) in a single carbon defect case. [•] A polarization function dependent ground state (triplet vs quintet) in a double carbon defect case. [•] Polarization function caused s and p contribution changes and thus the strong basis set effect. [Copyright &y& Elsevier]

• U 3 Si 5 is determined to be a brittle and magnetic metal. • The elastic strength of U 3 Si 5 is strongly anisotropic. • The brittleness of U 3 Si 5 is due to a structural transition under tensile strains. • Aluminum incorporation enhances the toughness of U 3 Si 5. Uranium silicide compounds have attracted intensive attention as candidate alternative fuels in commercial light water reactors (LWRs). In this work, the electronic, thermal, mechanical and elastic properties of U 3 Si 5 are comprehensively investigated based on first-principles density functional calculations and semi-classical Boltzmann transport theory. U 3 Si 5 is determined to be a brittle and magnetic metal, and thermal conductivity is dominated by its electronic contribution at high temperature. The ratio between the bulk and shear moduli is 1.205. In addition, the elastic ideal strength is strongly anisotropic, with the minimum value only 6.831 GPa at a uniaxial tensile strain of 0.07. This low strength is mainly caused by an emerged structural transition forming silicon-silicon bonds to absorb strain energy. Moreover, the influences of aluminum incorporation on the structural and elastic properties, and thermal conductivities of U 3 Si 5 are further studied. The aluminum atom prefers to replace the silicon atom at the vertex shared by the silicon triangles and pentagons. The incorporated atom impedes the structural transition, and enhances the toughness of U 3 Si 5. The results from this work may provide useful clue for the improvement in the application of U 3 Si 5. [Display omitted] [ABSTRACT FROM AUTHOR]

Silicon is the leading semiconductor material in microelectronic industry. Owing to the large surface to volume ratio, low-dimensional Si nanostructures, for instance, silicon quantum dots exhibit diverse electronic and optical properties. Passivating the surface of Si nanostructures by a suitable species is thereby required to stabilize and engineer the dot properties in different environment. Recent theoretical advances in the investigation of the excited state properties of silicon quantum dots (QDs) are reviewed in this article. The theoretical calculations reveal that the excited state relaxation is prevalent in hydrogenated silicon nanoparticles. Stokes shift due to structure relaxation in the excited state varies with the particle size. It is therefore desirable to minimize Stokes shift for the purpose of maximizing its quantum yield or efficiency in photoluminescence applications. Consequently, surface functionalization by a suitable species turns out to be the most effective avenue. Determination of proper passivating agent is of outmost importance to satisfy the practical necessity. All these intermingled factors are briefly addressed in this article. [ABSTRACT FROM AUTHOR]

Abstract: We performed systematic first principles calculations based on density functional theory to probe the energetics of dissociation of water molecules on small (TiO2) n (n =3, 4, 6, 8, and 10) clusters. We found that the (TiO2) n clusters have a strong ability to adsorb water molecules and the dissociative adsorption of water molecules on the surface of (TiO2) n clusters with a three step process is irreversible, size-dependent and energetically more favorable than the same on the surfaces of titanium oxide. Charged (TiO2) n cluster also have strong ability in H2O molecule splitting similar as neutral ones. The efficiency of water molecules dissociating on (TiO2) n cluster surface varies inversely with the cluster size due to the steric effect. Our results indicate a higher efficiency of small clusters of titanium oxide in dissociating water molecules than its low index surfaces of bulk terminated. [Copyright &y& Elsevier]