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Highly accurate potential energy surfaces are critically important for chemical reaction dynamics. The large number of degrees of freedom and the intricate symmetry adaption pose a big challenge to accurately representing potential energy surfaces (PESs) for polyatomic reactions. Recently, our group has made substantial progress in this direction by developing the fundamental invariant-neural network (FI-NN) approach. Here, we review these advances, demonstrating that the FI-NN approach can represent highly accurate, global, full-dimensional PESs for reactive systems with even more than 10 atoms. These multi-channel reactions typically involve many intermediates, transition states, and products. The complexity and ruggedness of this potential energy landscape present even greater challenges for full-dimensional PES representation. These PESs exhibit a high level of complexity, molecular size, and accuracy of fit. Dynamics simulations based on these PESs have unveiled intriguing and novel reaction mechanisms, providing deep insights into the intricate dynamics involved in combustion, atmospheric, and organic chemistry. [ABSTRACT FROM AUTHOR]

We present a comprehensive investigation into the dissociative chemisorption of HOD on a rigid Ni(100) surface using an approximate full-dimensional (9D) quantum dynamics approach, which was based on the time-dependent wave-packet calculations on a full-dimensional potential energy surface obtained through neural network fitting to density functional theory energy points. The approximate-9D probabilities were computed by averaging the seven-dimensional (7D) site-specific dissociation probabilities across six impact sites with appropriate relative weights. Our results uncover a distinctive bond-selective effect, demonstrating that the vibrational excitation of a specific bond substantially enhances the cleavage of that excited bond. The product branching ratios are substantially influenced by which bond undergoes excitation, exhibiting a clear preference for the product formed through the cleavage of the excited bond over the alternative product. [ABSTRACT FROM AUTHOR]

Collimation control of energetic plasma beams is crucial in the laser–plasma field. In this paper, we report on a self-collimated acceleration scheme for a plasma beam using an ultra-intense Laguerre–Gaussian (LG) laser irradiating a solid target. Three-dimensional (3D) particle-in-cell simulations show that a plasma beam with a high current density is stably formed by the radiation pressure of the hollow LG laser. The initial interaction of LG laser with solid target can be approximately researched by a deformable mirror model. Under the effect of the ponderomotive force of the LG laser, the plasma converges in the center axis to form a narrow beam. An elongated strong-magnetic tunnel (B ∼ 2 kT) is self-generated around the plasma beam, capable of trapping some electrons in a region with a radius of less than 500 nm (r < 500 nm). Compared with the case driven by the conventional Gaussian laser, the beam radius size is dramatically reduced from the microscale to hundreds on the nanoscale. The beam density is increased by at least ten times. Such an interesting scheme can provide a feasible and efficient way to achieve and enhance the collimation of energetic particle beams, which may benefit the general applications of fast ignition in inertial fusion, radiotherapy, realization of high-energy density states, and so on. [ABSTRACT FROM AUTHOR]

We present a new approach to incorporate the geometric phase in the time-dependent wave packet calculations based on the analytic diabatic potential energy matrices for two-state systems connecting via a conical intersection. The approach only requires information on the location of the conical intersection and the adiabatic potential energy surface of the ground electronic state and merely takes the same computational cost as a diabatic calculation. Demonstrations of the benchmark H + H2/HD reactions show that the new approach can accurately include the geometric phase in dynamics calculation and can be easily extended to the cold regime where the GP effects become more pronounced. Due to its simplicity and numerical efficiency, the new approach has the potential to extend the dynamics study of the geometric effects to a wide range of reaction systems. [ABSTRACT FROM AUTHOR]

Simple Summary: Tephritid fruit flies are among the most destructive agricultural pests of fruits and vegetables worldwide and have global significance, introducing barriers to the trade of fresh tropical commodities. The melon fly, Mediterranean fruit fly, oriental fruit fly, and Malaysian fruit fly have entered and become established in Hawaii and have been making frequent incursions into agriculturally important states of the U.S. mainland, such as California and Florida. Bait sprays containing protein food bait plus an insecticide such as spinosad have been a major control method for these fruit flies. However, resistance to bait sprays has been reported. In this study, we evaluated the potential insecticidal effects of five different non-nutritive sugars on four species of fruit flies established in Hawaii. Erythritol alone or erythritol plus sucrose formulations have a significant negative impact on their survival, suggesting a potential use of erythritol as a non-toxic management tool for the control of tropical tephritid fruit flies. Tephritid fruit flies are among the most destructive agricultural pests of fruits and vegetables worldwide and can impose trade barriers against the movement of fresh tropical commodities. Primary pre-harvest control methods for these flies rely on the spraying of conventional chemical insecticides or bait sprays. However, resistance to these control methods has been reported in fruit flies. Erythritol is a non-nutritive sugar alternative for human consumption, which has been tested and confirmed for its insecticidal properties against various insect pest species. In this study, using laboratory bioassays, we evaluated the insecticidal effect of erythritol alone or various erythritol formulations containing sucrose and/or protein on four tropical fruit fly species established in Hawaii (e.g., melon fly, Mediterranean fruit fly, oriental fruit fly, and Malaysian fruit fly). In addition, the effects of other non-nutritive hexose and pentose sugar alcohols, such as sorbitol, mannitol, and xylitol, were tested. Among the different standalone and combinatory treatments tested, 1M erythritol and a combinatory formulation of 2M erythritol + 0.5M sucrose appeared to be the most detrimental to the survival of all four species of tested flies, suggesting the potential of using erythritol as a non-toxic management tool for the control of tropical tephritid fruit flies. [ABSTRACT FROM AUTHOR]

To control wave propagation in phononic crystals (PnCs), it is crucial to perform the inverse design of dispersion engineering. In this article, a robust deep-learning method of dispersion engineering in two-dimensional (2D) PnCs is developed by combining deep neural networks (DNNs) with the genetic algorithm (GA), which can be easily extended to reach any target in the trained DNNs' calculation domain. A high-precision and robust DNN model to predict the bounds of energy bands of 2D PnCs is proposed, forming the forward prediction process. This DNN model shows high efficiency in the testing structures while keeping the mean relative error near 0.1%. The inverse design of PnCs is implemented by DNNs combined with the GA, building the back–forward retrieval process, which can exactly produce the desired PnCs with the expected bandgap bounds in only a few seconds. The proposed framework is promising for constructing arbitrary PnCs on demand. [ABSTRACT FROM AUTHOR]

We present a theoretical study on plasmonic properties of an Au based nanoshell structure in which the localized surface plasmon resonances (LSPRs) and the inter-band electronic transitions (IBTs) are presented. The optical properties of Au nanoshell are depicted by a corrected dielectric function of Drude-Lorentz mode, and Mie theory is applied to calculate the absorption efficiencies. It shows that there are two localized surface plasmon absorption peaks, which are induced from the outside LSPRs and the inside LSPRs, respectively. The positions of these two peaks can shift by changing core radius and shell thickness. By varying the core radius and thickness of the shells, the LSPRs are modulated with the IBTs, leading to the strong interactions between the LSPRs and the IBTs. It is found that the LSPRs and IBTs can couple with each other and the new resonance absorption peaks can be observed. Our results show that the LSPRs are enhanced by the IBTs. This enhancement can be applied to improve biosensor signals and advanced plasmonic applications. [ABSTRACT FROM AUTHOR]

A micrometer-scale "plasma lens" self-constructed by the prepulse and main pulse of the Laguerre–Gaussian (LG) laser is realized to enhance the collimation and acceleration of proton beams in a target normal sheath field acceleration mechanism. Hydrodynamic FLASH and particle-in-cell simulations are carried out and find that a collimated proton source with beam divergence ∼2.7° is generated by the LG laser, which is smaller than the case driven by the traditional Gaussian laser. It demonstrates that the curved sheath field on the "plasma lens" plays an important role in the beam collimation. Such an approach considerably relaxes the constraints of complex design for the target fabrication and auxiliary laser pulse, opening new doors for high-repetition-rate collimated proton accelerations for innovative applications in upcoming high-repetition-rate petawatt laser systems. [ABSTRACT FROM AUTHOR]

We developed a systematic theoretical study of nonlinear optical properties of semiconductors. The eight-band k⋅p model and the energy-balance equation are employed to calculate the transmission and optical absorption coefficients in the presence of both the linear one-photon absorption and the nonlinear two-photon absorption (TPA) processes. A substantial reduction of the optical transmittance far below the band-gap can be observed under relatively high-intensity radiation fields due to the nonlinear TPA. The TPA-induced optical transmittance decreases with increasing intensity of the radiation fields. Our theoretical results are in line with those observed experimentally. The theoretical approach can be applied to understand the nonlinear optical properties of semiconductors under high-field conditions. [ABSTRACT FROM AUTHOR]

Fast and high-order accurate algorithms for three-dimensional elastic scattering are of great importance when modeling physical phenomena in mechanics, seismic imaging, and many other fields of applied science. In this paper, we develop a novel boundary integral formulation for the three-dimensional elastic scattering based on the Helmholtz decomposition of elastic fields, which converts the Navier equation to a coupled system consisted of Helmholtz and Maxwell equations. An FFT-accelerated separation of variables solver is proposed to efficiently invert boundary integral formulations of the coupled system for elastic scattering from axisymmetric rigid bodies. In particular, by combining the regularization properties of the singular boundary integral operators and the FFT-based fast evaluation of modal Green’s functions, our numerical solver can rapidly solve the resulting integral equations with a high-order accuracy. Several numerical examples are provided to demonstrate the efficiency and accuracy of the proposed algorithm, including geometries with corners at different wavenumbers. [ABSTRACT FROM AUTHOR]

Inorganic phosphate (Pi) is an essential nutrient, which is often served as a limiting factor in plant growth. It has been reported that SPL family members, such as SPL3, regulate Pi deficiency responses by controlling the expression of Pi deficiency responsive genes. To elucidate whether SPL9 respond to low phosphorus stress, we investigated the phenotypes and conducted RNA sequencing analysis in transgenic Arabidopsis thaliana with overexpressing rSPL9 (R9) under conditions of both normal and low Pi availability. Compared with wild-type plants, R9 showed decreased anthocyanin accumulation and increased Pi contents in shoots under Pi deficiency. Through RNA-seq analysis compared with wild-type plants, we detected 217 genes significantly differentially expressed in conditions of Pi sufficiency, and 121 genes differentially expressed in conditions of Pi deficiency in R9 plants. Under Pi deficiency, MYB62 and ZAT6 are two important differentially expressed genes (DEGs) that both regulate the Pi uptake processes. In addition, these DEGs included multiple protein kinases, jasmonic acid response genes and genes related to salt stress responses. Genes associated with hydrolase and transferase activity were also differentially regulated by Pi deficiency, such as cytochrome P450 monooxygenases. Of particular note, the transcription factor AP2-EREBP and members of the bHLH family were among the most significantly differentially regulated genes identified under both Pi sufficient and Pi deficient conditions. In conclusion, our analysis of the R9 transcriptome highlights the importance of SPL9 under conditions of Pi-deficiency. Except for stress and defense response genes, the R9 transcriptome also characterized the induction of ethylene or jasmonic acid signaling under Pi deficiency. [ABSTRACT FROM AUTHOR]

The genetic architectures of agronomic and yield-related traits are expected to involve multiple loci that are unlikely all to segregate for alternative alleles in a single biparental population. Therefore, the identification of quantitative trait loci (QTL) that are expressed in diverse genetic backgrounds of multiple bi-parental populations provides evidence about both background-specific and common genetic variants. The purpose of this study was to map QTLs for agronomic and yield related traits using three connected mapping populations of different genetic backgrounds, to gain insight into the genomic landscape of these important traits in elite Ethiopian sorghum germplasm. The three bi-parental populations, each with 207 F 2:3 lines were evaluated using an alpha lattice design with two replications under two moisture stress environments. Data analysis was done separately for each population using composite interval mapping, finding a total of 105 QTLs. All the QTLs identified from individual populations were projected on a combined consensus map, comprising a total of 25 meta QTLs for seven traits. The consensus map allowed us to deduce locations of a larger number of markers than possible in any individual map, providing a reference for genetic studies in different genetic backgrounds. The meta QTLs identified in this study could be used for marker-assisted breeding programs in sorghum after validation. Only one trait, reduced leaf senescence, showed a striking bias of allele distribution, indicating substantial standing variation among the lines that might be employed in improving drought tolerance of sorghum. [ABSTRACT FROM AUTHOR]

The mode-specific dynamics for the dissociative chemisorption of H2O on rigid Ni(100) is investigated by approximate nine-dimensional (9D) quantum dynamics calculations. The vibrational state-specific 9D dissociation probabilities are obtained by site-averaging the site-specific seven-dimensional results based on an accurate full-dimensional potential energy surface newly developed by neural network fitting to density functional theory energy points with the revised version of the Perdew, Burke, and Ernzerhof functional. The mode specificity of H2O/Ni(100) is very different from that of H2O/Ni(111) or H2O/Cu(111) whose reactivity enhancement by vibrational excitations is quite efficient. For H2O/Ni(100), it is found that the excitation in the symmetric stretching mode is more efficacious than increasing the translational energy in promoting the reaction, while the excitations in the asymmetric stretching mode and bending mode are less efficacious than the translational energy at low collision energies. These interesting observations can be attributed to the near central-barrier reaction for H2O/Ni(100), as well as large discrepancies between the site-specific mode specificities at different impact sites. The mode-specific dynamics obtained in this study is different from that obtained with the reaction path Hamiltonian approach, indicating the importance of full-dimensional quantum dynamics for gas–surface reactions. [ABSTRACT FROM AUTHOR]

We employ the initial state-selected time-dependent wave packet approach to an atom-triatom reaction to study the H + HOD → OH + HD/OD + H2 reaction without the centrifugal sudden approximation, based on an accurate potential energy surface which was recently developed by neural network fitting to high level ab initio energy points. The total reaction probabilities and integral cross sections, which are the exact coupled-channel results, are calculated for the HOD reactant initially in the ground and several vibrationally excited states, including the bending excited state, OD stretching excited states, OH stretching excited states, and combined excitations of them. The reactivity enhancements from different initial states of HOD are presented, which feature strong bond-selective effects of the reaction dynamics. The current results for the product branching ratios, reactivity enhancements, and relative cross sections are largely improved over the previous calculations, in quantitatively good agreement with experiment. The thermal rate constant for the title reaction and the contributions from individual vibrational states of HOD are also obtained. [ABSTRACT FROM AUTHOR]

Eight-dimensional (8D) transition-state wave packet simulations have been performed on two latest potential energy surfaces (PES), the Zhou-Fu-Wang-Collins-Zhang (ZFWCZ) PES [Y. Zhou, B. Fu, C. Wang, M. A. Collins, and D. H. Zhang, J. Chem. Phys. 134, 064323 (2011)] and the Xu-Chen- Zhang (XCZ)-neural networks (NN) PES [X. Xu, J. Chen, and D. H. Zhang, Chin. J. Chem. Phys. 27, 373 (2014)]. Reaction rate constants for both the H+CH4 reaction and the H2+CH3 reaction are calculated. Simulations of the H+CH4 reaction based on the XCZ-NN PES show that the ZFWCZ PES predicts rate constants with reasonable high accuracy for low temperatures while leads to slightly lower results for high temperatures, in line with the distribution of interpolation error associated with the ZFWCZ PES. The 8D H+CH4 rate constants derived on the ZFWCZ PES compare well with full-dimensional 12D results based on the equivalent m-ZFWCZ PES, with a maximum relative difference of no more than 20%. Additionally, very good agreement is shown by comparing the 8D XCZ-NN rate constants with the 12D results obtained on the ZFWCZ-WM PES, after considering the difference in static barrier height between these two PESs. The reaction rate constants calculated for the H2+CH3 reaction are found to be in good consistency with experimental observations. [ABSTRACT FROM AUTHOR]

Seven-dimensional time-dependent wave packet calculations have been carried out for the title reaction to obtain reaction probabilities and cross sections for CHD3 in JO= 1, 2 rotationally excited initial states with kO= 0 - JO (the projection of CHD3 rotational angular momentum on its C3 axis). Under the centrifugal sudden (CS) approximation, the initial states with the projection of the total angular momentum on the body fixed axis (KO) equal to kO are found to be much more reactive, indicating strong dependence of reactivity on the orientation of the reagent CHD3 with respect to the relative velocity between the reagents H and CHD3. However, at the coupled-channel (CC) level this dependence becomes much weak although in general the K0 specified cross sections for the KO= kO initial states remain primary to the overall cross sections, implying the Coriolis coupling is important to the dynamics of the reaction. The calculated CS and CC integral cross sections obtained after KO averaging for the JO= 1, 2 initial states with all different k0 are essentially identical to the corresponding CS and CC results for the JO= 0 initial state, meaning that the initial rotational excitation of CHD3 up to JO= 2, regardless of its initial kO, does not have any effect on the total cross sections for the title reaction, and the errors introduced by the CS approximation on integral cross sections for the rotationally excited JO= 1, 2 initial states are the same as those for the JO= 0 initial state. [ABSTRACT FROM AUTHOR]

We study the difference between the energy transfer rate and the engine efficiency with a microscopic model, widely used in the theoretical description of solar cells, as well as in light-harvesting systems. We show no violation of the second law of thermodynamics by correctly assessing the useful output work, even with the simple model treating the later work conversion as a simple "sink". [ABSTRACT FROM AUTHOR]

We present a potential energy surface fitting scheme based on multiplicative artificial neural networks. It has the sum of products form required for efficient computation of the dynamics of multidimensional quantum systems with the multi configuration time dependent Hartree method. Moreover, it results in analytic potential energy matrix elements when combined with quantum dynamics methods using Gaussian basis functions, eliminating the need for a local harmonic approximation. Scaling behavior with respect to the complexity of the potential as well as the requested accuracy is discussed. [ABSTRACT FROM AUTHOR]

A framework for quantum state-to-state integral and differential cross sections of triatomic reactive scattering using the Multi-Configuration Time-Dependent Hartree (MCTDH) method is introduced, where a modified version of the Heidelberg MCTDH package is applied. Parity of the system is adopted using only non-negative helicity quantum numbers, which reduces the basis set size of the single particle functions in angular degree of freedom almost by half. The initial wave packet is constructed in the space-fixed frame, which can accurately account for the centrifugal potential. By using the reactant-coordinate-based method, the product state-resolved information can be accurately extracted. Test calculations are presented for the H + H2 reactive scattering. This work demonstrates the capability of the MCTDH method for extracting accurate state-to-state integral and differential cross sections. As an efficient scheme for high-dimensional problems, the MCTDH method may be promising for the study of product state-resolved cross sections for polyatomic reactive systems. [ABSTRACT FROM AUTHOR]

The interfacial chemistry of thin Al (∼3 nm) and Hf (∼2 nm) metal films deposited by electron beam (e-beam) evaporation on native oxide InP (100) samples at room temperature and after annealing has been studied by in situ angle resolved X-ray photoelectron spectroscopy and low energy ion scattering spectroscopy. The In-oxides are completely scavenged forming In-In/In-(Al/Hf) bonding after Al and Hf metal deposition. The P-oxide concentration is significantly decreased, and the P-oxide chemical states have been changed to more P-rich oxides upon metal deposition. Indium diffusion through these metals before and after annealing at 250 °C has also been characterized. First principles calculation shows that In has lower surface formation energy compared with Al and Hf metals, which is consistent with the observed indium diffusion behavior. [ABSTRACT FROM AUTHOR]

The dependence of the 'self cleaning' effect of the substrate oxides on substrate temperature during atomic layer deposition (ALD) of HfO2 on various chemically treated and native oxide InP (100) substrates is investigated using in situ X-ray photoelectron spectroscopy. The removal of In-oxide is found to be more efficient at higher ALD temperatures. The P oxidation states on native oxide and acid etched samples are seen to change, with the total P-oxide concentration remaining constant, after 10 cycles of ALD HfO2 at different temperatures. An (NH4)2 S treatment is seen to effectively remove native oxides and passivate the InP surfaces independent of substrate temperature studied (200 °C, 250 °C and 300 °C) before and after the ALD process. Density functional theory modeling provides insight into the mechanism of the changes in the P-oxide chemical states. [ABSTRACT FROM AUTHOR]

The layer-dependent optoelectronic properties of monolayer, bilayer and trilayer black phosphorus (BP) are studied by using the first-principles calculations based on density functional theory (DFT). The valence band splits and the density of states (DOS) in the conduction band obviously shift to the Fermi surface with the increased layer number. The atomic p orbital of BP plays an decisive role in determining the electronic and optical properties, which are drastically different from those of graphene and transition metal dichalogenides (TMDs). The increase of the layer number leads to the metal characteristics. The extinction coefficient and photoconductivity show strong optical responses to the ultraviolet (UV) light, which further increase with the number of layers. BP layers can reflect UV rays effectively because of their metallic properties in the UV energy range. Our study shows that the interlayer interaction can intensely change the electronic and optical properties of BP. [ABSTRACT FROM AUTHOR]

Membrane concentration processes have been used to treat anaerobically digested (AD) slurry for nutrient recovery and pollutant removal; however, these methods often face the challenges of low processing stability and efficiency. In this study, the performance (processing stability and efficiency) of three membrane concentration processes, including nanofiltration (NF), reverse osmosis (RO1) and two-stage NF-RO (NF-RO2), in treating ceramic membrane-pretreated swine manure AD slurry was evaluated and compared. Nutrient and antibiotic redistribution in the concentrate and permeate was also investigated. Results show that NF-RO2 had higher processing stability and efficiency than the other two processes. High nutrient recoveries of 61.9% for total nitrogen, 56.3% for total phosphorus, and 67.0% for potassium in the concentrates were observed in NF-RO2. The removal rates for antibiotics sulfamethazine and oxytetracycline in NF-RO2 were 99.3% and 81.9%, respectively. Therefore, NF-RO is an effective way to recover nutrients and remove pollutants from AD slurry. [ABSTRACT FROM AUTHOR]

People who use injection drugs (PWID) experience high rates of HIV acquisition and, as a result of lower rates of optimal access and adherence to combination antiretroviral therapy (ART), experience worse HIV treatment outcomes than other key affected populations. However, the incidence and risk factors for the development of AIDS among HIV-positive PWID have not been completely described. We used data from a community-recruited prospective cohort of HIV-positive PWID in Vancouver, Canada, a setting with universal no-cost ART and a comprehensive clinical monitoring registry. We used multivariable extended Cox models to identify factors associated with time to AIDS. Between 1996 and 2017, 396 participants, including 140 (35.4%) women, were followed for a median of 39.0 months (interquartile range: 16.6–76.2), among whom 165 (41.7%) developed AIDS. In a multivariable model, homelessness (Adjusted Hazard Ratio [AHR] = 1.76 (1.18–2.61)) and injection drug use within the preceding six months (AHR = 1.74 (1.17–2.58)) were independently associated with a higher risk of developing AIDS. Despite widespread scale-up of programmes to improve ART utilization, significant risk factors for the development of AIDS remain among HIV-positive PWID in this setting. [ABSTRACT FROM AUTHOR]

The initial state-selected time-dependent wave packet approach to an atom-triatom reaction is employed to study the H + H2O → H2 + OH reaction without the centrifugal sudden approximation. The total reaction probabilities and integral cross sections, which are the exact coupled-channel results, are calculated for the H2O reactant initially in the ground and several vibrationally excited states, including bending excited states, first and second stretching excited states, and simultaneous excitations of both bending and stretching modes. The reactivity enhancements from different initial states of the H2O reagent are presented and discussed in detail. The thermal rate constant for the title reaction and the contributions to this coefficient from individual vibrational states of H2O are also obtained and compared with the previous theoretical and experimental data. [ABSTRACT FROM AUTHOR]

Herbivorous insects may benefit from avoiding the smell produced by phytopathogens infecting plant host tissue if the infected tissue reduces insect fitness. However, in many cases the same species of phytopathogen can also infect host plant tissues that do not directly affect herbivore fitness. Thus, insects may benefit from differentiating between pathogen odors emanating from food and nonfood tissues. This is based on the hypothesis that unnecessarily staying attentive to pathogen odor from nonfood tissue may incur opportunity costs associated with not responding to other important survival functions. In this study adults of Drosophila suzukii Matsumura, an invasive larval frugivore, showed reduced attraction to the odor of raspberry fruit, a food tissue, when infected with Botrytis cinerea Pers., a ubiquitous phytopathogen, in favor of odors of uninfected raspberry fruit. Moreover, D. suzukii oviposited fewer eggs on infected raspberry fruit relative to uninfected raspberry fruit. Larval survival and adult size after eclosion were significantly reduced when reared on B. cinerea‐infected raspberry relative to uninfected fruit. Interestingly, when the behavioral choice experiment was repeated using Botrytis‐infected vs. ‐uninfected strawberry leaves, a nonfood tissue, in combination with fresh raspberry fruit, odor from B. cinerea‐infected leaves did not reduce D. suzukii attraction to raspberries relative to raspberries with uninfected leaves. These behavioral results illustrate the important role context can play in odor‐mediated interactions between insects, plants and microbes. We discuss implications of our findings for developing a repellent that can be useful for the management of D. suzukii. [ABSTRACT FROM AUTHOR]

We investigate experimentally the terahertz (THz) optoelectronic properties of monolayer (ML) tungsten disulfide (WS2) placed on different substrates using THz time-domain spectroscopy (TDS). We find that the THz optical response of n-type ML WS2 depends sensitively on the choice of the substrate. This dependence is found to be a consequence of substrate induced charge transfer, extra scattering centers, and electronic localization. Through fitting the experimental results with the Drude–Smith formula, we can determine the key sample parameters (e.g., the electronic relaxation time, electron density, and electronic localization factor) of ML WS2 on different substrates. The temperature dependence of these parameters is examined. Our results show that the THz TDS technique is an efficient non-contact method that can be utilized to characterize and investigate the optoelectronic properties of nano-devices based on ML WS2. [ABSTRACT FROM AUTHOR]

Aims: Poly‐γ‐glutamic acid (γ‐PGA) is an excellent water‐soluble biosynthesis material. To confirm the rate‐limiting steps of γ‐PGA biosynthesis pathway, we introduced a heterologous Bacillus strain pathway and employed an enzyme‐modulated dismemberment strategy in Escherichia coli. Methods and Results: In this study, we heterologously introduced the γ‐PGA biosynthesis pathway of two laboratory‐preserved strains—Bacillus amyloliquefaciens FZB42 and Bacillus subtilis 168 into E. coli, and compared their γ‐PGA production levels. Next, by changing the plasmid copy numbers and supplying sodium glutamate, we explored the effects of gene expression levels and concentrations of the substrate l‐glutamic acid on γ‐PGA production. We finally employed a two‐plasmid induction system using an enzyme‐modulated dismemberment of pgsBCAE operon to confirm the rate‐limiting genes of the γ‐PGA biosynthesis pathway. Conclusion: Through heterologously over‐expressing the genes of the γ‐PGA biosynthesis pathway and exploring gene expression levels, we produced 0·77 g l−1 γ‐PGA in strain RSF‐EBCAE(BS). We also confirmed that the rate‐limiting genes of the γ‐PGA biosynthesis pathway were pgsB and pgsC. Significance and Impact of the Study: This work is beneficial to increase γ‐PGA production and study the mechanism of γ‐PGA biosynthesis enzymes. [ABSTRACT FROM AUTHOR]

Aims: Interaction between programmed death‐1 ligand (PD‐L1) and its receptor programmed death 1 (PD‐1) on T cells inactivates antitumour immune responses. PD‐L1 expression has been associated with poor prognosis in renal cell carcinoma (RCC) and predicts adverse outcome. This study was designed to evaluate the impact of PD‐L1 expression and the immune microenvironment on the clinical outcome in Xp11 translocation renal cell carcinoma (TRCC) and, therefore, their potential relevance as prognostic biomarkers. Methods and results: The present retrospective analysis investigated expression of PD‐L1 and immune cells CD8, CD4, CD3, forkhead box protein 3 (FoxP3) and PD‐1 in TRCC compared to other types of RCC. FFPE specimens were collected between 2011 and 2017 from 311 patients who underwent nephrectomy at our institution for RCC. Specimens were immunostained for PD‐L1, CD8, CD4, CD3, FoxP3 and PD‐1, and an outcome analysis was conducted. PD‐L1 expression rate was highest in TRCC (68%, 16 of 25), followed by mucinous tubular and spindle cell RCC and collecting duct carcinoma (33%, one of three), papillary RCC (27%, seven of 26), clear cell RCC (16%, 29 of 233), chromophobe RCC (11%, two of 18) and multilocular cystic RCC (0%, none of three). In TRCC, PD‐L1 expression was associated with poor recurrence‐free survival (RFS) (P = 0.041). The CD4high and FoxP3high groups showed a significantly shorter RFS (P = 0.05 and P = 0.031, respectively) compared to CD4low and FOXPlow groups. Conclusion: PD‐L1 expression was higher in TRCC than in other types of RCC. High PD‐L1 tumour cell expression and tumour infiltration by CD4+ and FoxP3+ immune cells were associated with poor RFS in TRCC. [ABSTRACT FROM AUTHOR]

The forming mechanism of anomalous eutectic structure (AES) in undercooled eutectic alloys has been a controversial issue. In this work, we conducted in situ observation of the AES forming process in an Ni-18.7 at.% Sn eutectic alloy using a high-temperature laser scanning confocal microscope. Our results provide an evidence of the AES formation induced by remelting of primary eutectic lamellae constituted by Ni 3 Sn and α-Ni lamellae. During recalescence, a pronounced remelting of the Ni 3 Sn phase into liquid occurs, while the α-Ni lamellae subject to a rapid morphological transition into granules. Eventually, the completion of solidification leads to the AES formation. Image, graphical abstract [ABSTRACT FROM AUTHOR]

The Microwave Radiation Imager (MWRI) on board the FengYun‐3 (FY‐3) series of satellites can provide global observations four times daily, which significantly improves the ability to monitor large‐scale natural disasters. There is noticeable striping noise in brightness temperature observations from the MWRIs on board the FY‐3B, FY‐3C and FY‐3D satellites. The central frequencies of all MWRI channels are in the atmospheric window region. In this article, a modified principal component analysis/ensemble empirical mode decomposition method proposed by Zou et al. in 2017 was applied to deal with the striping noise in MWRI measurements. Results reveal that the magnitude of the striping noise in the brightness temperature observations of MWRI channels 10 are about ±1.2 K for FY‐3B, ±1.1 K for FY‐3C and ± 0.8 K for FY3D. The striping noise in FY‐3D MWRI measurements is significantly reduced, compared with the striping noise in FY‐3B and FY‐3C MWRI measurements. Striping features will appear in the liquid water path (LWP) distribution if LWP is retrieved from brightness temperatures without removing the striping noise. The differences between LWP retrieved from the MWRI observations with and without striping noise mitigation could be as large as 0.07 kg·m−2. It is thus necessary to remove striping noise before any MWRI data applications. [ABSTRACT FROM AUTHOR]

In this work, the permutation invariant polynomial neural network (PIP-NN) approach is employed to construct a quasi-diabatic Hamiltonian for system with non-Abelian symmetries. It provides a flexible and compact NN-based diabatic ansatz from the related approach of Williams, Eisfeld, and co-workers. The example of H 3 + is studied, which is an (E + A) × (e + a) Jahn–Teller and Pseudo-Jahn–Teller system. The PIP-NN diabatic ansatz is based on the symmetric polynomial expansion of Viel and Eisfeld, the coefficients of which are expressed with neural network functions that take permutation-invariant polynomials as input. This PIP-NN-based diabatic ansatz not only preserves the correct symmetry but also provides functional flexibility to accurately reproduce ab initio electronic structure data, thus resulting in excellent fits. The adiabatic energies, energy gradients, and derivative couplings are well reproduced. A good description of the local topology of the conical intersection seam is also achieved. Therefore, this diabatic ansatz completes the PIP-NN based representation of DPEM with correct symmetries and will enable us to diabatize even more complicated systems with complex symmetries. [ABSTRACT FROM AUTHOR]

The exchange processes of D + H2O and D + HOD reactions are studied using initial state-selected time-dependent wave packet approach in full dimension. The total reaction probabilities for different partial waves, together with the integral cross sections, are obtained both by the centrifugal sudden (CS) approximation and exact coupled-channel (CC) calculations, for the H2O(HOD) reactant initially in the ground rovibrational state. In the CC calculations, small resonance peaks in the reaction probabilities and quick diminishing of the resonance peaks with the increase of total angular momenta J do not lead to clear step-like features just above the threshold in the cross sections for the title reactions, which are different in other isotopically substituted reactions where the hydrogen atom was included as the reactant instead of the deuterium atom [B. Fu, Y. Zhou, and D. H. Zhang, Chem. Sci. 3, 270 (2012); B. Fu and D. H. Zhang, J. Phys. Chem. A 116, 820 (2012)]. It is interesting that the shape resonance-induced features resulting from the reaction tunneling are significantly diminished accordingly in the reactions of the deuterium atom and H2O or HOD, owing to the weaker tunneling capability of the reagent deuterium atom in the title reactions than the reagent hydrogen atom in other reactions. In the CS calculations, the resonance peaks persist in many partial waves but cannot survive the partial-wave summations. The cross sections for the D′ + H2O → D′OH + H and D′ + HOD → D′OD + H reactions are substantially larger than those for the D′ + HOD → HOD′ + D reaction, indicating that the D′/H exchange reactions are much more favored than the D′/D exchange. [ABSTRACT FROM AUTHOR]

(Na1-xKx)0.5Bi0.5TiO3 (NBT-KBT-100 x) thin films were deposited on Pt/Ti/SiO2/Si(100) by metal organic decomposition, and the effects of potassium content (x = 0.15, 0.18, 0.20, 0.25) on ferroelectric, piezoelectric, dielectric properties of the thin films, and the temperature dependence of dielectric permittivity of NBT-KBT-18 thin film were investigated in detail. NBT-KBT-18 thin film is of the largest effective piezoelectric coefficient d33eff, remnant polarization 2Pr, spontaneous polarization 2 Ps, dielectric constant &eh;r, and the lowest dielectric loss among the thin films. The dielectric constants decrease steeply with the increase of frequency, and there are a series of resonance peaks with Debye-like relaxation. In dielectric temperature spectra, two abnormal peaks corresponding to depolarization temperature and Curie temperature are at the range of 75-90 °C and 295-320 °C, and they are associated with the phase transitions. Based on the dielectric relaxation theory, Debye-like relaxation and diffused phase transition/frequency dispersion are interpreted by space charge polarization and polar nanoregions. Because of the centrosymmetric paraelectric phase, the 2 Ps and &eh;r of NBT-KBT-100 x thin film are responsible for the d33eff according to phenomenological equation. The improved d33eff may make NBT-KBT-18 thin film a promising candidate for piezoelectric thin film devices, and the enhanced Curie temperature will offer useful guidelines of safe working temperature for potential application in micro-electro-mechanical system. [ABSTRACT FROM AUTHOR]

We present a theoretical investigation on the transport properties of graphene in the presence of high dc driving fields. Considering electron interactions with impurities and acoustic and optical phonons in graphene, we employ the momentum- and energy-balance equations derived from the Boltzmann equation to self-consistently evaluate the drift velocity and temperature of electrons in graphene in the linear and nonlinear response regimes. We find that the current-voltage relation exhibits distinctly nonlinear behavior, especially in the high electric field regime. Under the action of high-fields the large source-drain (sd) current density can be achieved and the current saturation in graphene is incomplete with increasing the sd voltage Vsd up to 3 V. Moreover, for high fields, Vsd>0.1 V, the heating of electrons in graphene occurs. It is shown that the sd current and electron temperature are sensitive to electron density and lattice temperature in the graphene device. This study is relevant to the application of graphene as high-field nano-electronic devices such as graphene field-effect transistors. [ABSTRACT FROM AUTHOR]

We describe a time-dependent wavepacket based method for the calculation of the state-to-state cross sections for the Cl+H2 reaction including all couplings arising from the nonzero spin and electronic orbital angular momenta of the Cl atom. Reactant-product decoupling allows us to use a physically correct basis in both the reactant and the product arrangements. Our calculated results agree well with the experimental results of Yang and co-workers. We also describe a model with two coupled potential energy surfaces, which includes the spin-orbit coupling, which is responsible for the largest non-Born–Oppenheimer effects in the Cl+H2 reaction but neglects the off-diagonal electronically diabatic coupling and all Coriolis couplings due to the electronic spin and orbital angular momenta. The comparison of the results of the full six-state and two-state models with an electronically adiabatic (one-state) description reveals that the latter describes well the reaction out of the ground spin-orbit state, while the two-state model, which is computationally much faster than the full six-state model, describes well the reaction from both the ground and excited spin-orbit states. [ABSTRACT FROM AUTHOR]

We present a theoretical study of the optoelectronic properties of bilayer graphene. The optical conductance and transmission coefficient are calculated using the energy-balance equation derived from a Boltzmann equation for an air/graphene/dielectric-wafer system. For short wavelengths (λ<0.2 μm), we obtain the universal optical conductance σ=e2/(2h). Interestingly, there exists an optical absorption window in the wavelength range 10–100 μm, which is induced by different transition energies required for inter- and intra-band optical absorptions in the presence of the Moss–Burstein effect. As a result, the position and width of this absorption window depend sensitively on temperature, carrier density, and sample mobility of the system. These results are relevant for applications of recently developed graphene devices in advanced optoelectronics such as the infrared photodetectors. [ABSTRACT FROM AUTHOR]

Thawed Gaussian wavepackets have been used in recent years to compute approximations to the thermal density matrix. From a numerical point of view, it is cheaper to employ frozen Gaussian wavepackets. In this paper, we provide the formalism for the computation of thermal densities using frozen Gaussian wavepackets. We show that the exact density may be given in terms of a series, in which the zeroth order term is the frozen Gaussian. A numerical test of the methodology is presented for deep tunneling in the quartic double well potential. In all cases, the series is observed to converge. The convergence of the diagonal density matrix element is much faster than that of the antidiagonal one, suggesting that the methodology should be especially useful for the computation of partition functions. As a by product of this study, we find that the density matrix in configuration space can have more than two saddle points at low temperatures. This has implications for the use of the quantum instanton theory. [ABSTRACT FROM AUTHOR]

This paper presents a method of restoring signals in terahertz spectroscopy by removing the distortion from the observed terahertz signals. The distortion is generated by the absorption and scattering of gas molecules and water vapor in the atmosphere during the transmission of terahertz beams through the air from the source to the spectrometer. Such atmospheric degradation causes spurious spectral dips and peaks in the terahertz spectrum, which often obscure the spectral peaks specific to the material of interest. This fact makes it challenging to measure the terahertz spectroscopic signatures of objects in a humid air environment, even at a short distance of approximately 1 m. A terahertz signal restoration filter based on a nonlinear artificial neural network model effectively removes noisy absorption peaks in terahertz spectra caused by atmospheric degradation. [ABSTRACT FROM AUTHOR]

A mode coupling theory (MCT) expression for the self-diffusion coefficient follows simply when the soft fluctuating intermolecular forces are projected along a collective densitylike variable. The projected forces separate into two parts: from the gradient of the direct correlation function (dcf), and from the short range forces. The time correlation function of the dcf-derived forces is related to the excess entropy, as shown by Ali [J. Chem. Phys. 124, 144504 (2006)], and this relationship is evaluated for two variations of MCT. As for hard spheres, the derivation of an analogous MCT is beset by a number of singularities that kinetic theory could not remove. A justifiable MCT for hard sphere fluids may not exist. [ABSTRACT FROM AUTHOR]

A classical density functional theory is applied to the calculation of the fluid-solid transition for hard spheres, using the Percus-Yevick (PY) direct correlation function. Three algebraic conditions are established for the coexistence densities and the Lindemann parameter. The terms neglected in the present analysis are small and the present theory, in our eyes, is essentially an exact solution given the PY approximation. No fluid-solid transition is found for the bcc lattice, whereas for expanded fcc lattices, the agreement with previous density functional theory-based theories is good. [ABSTRACT FROM AUTHOR]

The time-dependent wave packet method was extended to calculate the state-to-state differential cross section for the title four-atom abstraction reaction with H2O in the ground rovibrational state. One spectator OH bond length was fixed in the study, but the remaining five degrees of freedom were treated exactly. It was found that (a) the differential cross section changes from being strongly backward peaked at low collision energy to sideward scattering at E=1.4 eV, and (b) the rotational state-resolved differential cross section for H2 differs substantially from that for OH. [ABSTRACT FROM AUTHOR]

[Display omitted] • Destabilization behavior of nanostructured Ag/Cu multilayer observed in situ in transmission electron microscope. • Destabilization of nanostructured Ag/Cu multilayer originated from the interfacial instability perturbation. • Capillary force dominated the transition after compositional gradient initiating. • The Ag/Cu multilayer with similar lamellar thickness tended to form stable grooves during roughening. Nanostructured metallic multilayered composites have many excellent properties due to their high-density heterophase interfaces, but they also pose challenges to the thermal stability of their multilayered structures. In this work, destabilization behavior of nanostructured Ag/Cu multilayer with an individual layer thickness of 40 nm prepared by multicomponent accumulative roll bonding is directly observed by transmission electron microscope. The results show that the destabilization of the nanostructured Ag/Cu multilayer originates from the interfacial instability perturbation driven by compositional gradient and capillary force. The subsequent destabilizing process is closely related to the cross-sectional ratio of the lamellar structure. When the thickness difference between adjacent lamellae is large, the lamellae with smaller thickness will follow a destabilizing sequence of perturbation → necking → pinching → termination migration. While the thickness of adjacent lamellae is similar, the perturbed lamellae tend to form stable grooves during roughening. [ABSTRACT FROM AUTHOR]

A new continuous configuration time-dependent self-consistent field method has been developed to study polyatomic dynamical problems by using the discrete variable representation for the reaction system, and applied to a reaction system coupled to a bath. The method is very efficient because the equations involved are as simple as those in the traditional single configuration approach, and can account for the correlations between the reaction system and bath modes rather well. [ABSTRACT FROM AUTHOR]

The initial state selected time-dependent wave packet method has been extended to calculate the total reaction probability for atom-triatom reactions with total angular momentum J > 0 by treating both bonds in the triatom reagent reactively. The total exchange and abstraction reaction probabilities for the title reaction with J = 15 calculated with 2 K-blocks (the projection of the total angular momentum on the body-fixed axis) show that one has to treat both OH bonds in the H[SUB2]O reagent reactively for the exchange reaction, but for the abstraction reaction one can treat one OH bond as a spectator bond to get accurate results. This is in accord with what had been found for the total reaction probabilities for J=0 [Phys. Rev. Lett. 89, 103201 (2002)]. The J= 15 reaction probabilities also show that the CS (centrifugal sudden) approximation is inadequate for the title reaction, in particular for the abstraction reaction. The integral cross sections for the abstraction reaction, calculated without the CS approximation but by freezing one OH bond in the H[SUB2]O reagent for the ground and first vibrationally excited states, are found to be substantially larger than the corresponding CS integral cross sections. However, the integral cross section for the ground vibrational state is still much smaller than the existing experimental result. Since the treatment of freezing OH bond is not expected to introduce any noticeable error, it is conceivable that the experiments overestimated the integral cross section for the abstraction reaction. [ABSTRACT FROM AUTHOR]

The initial state selected time-dependent wave packet method has been developed to study the H+ CH[sub 4] reaction in seven dimensions by employing the model developed by Palma and Clary [J. Chem. Phys. 112, 1859 (2000)]. The latter eight-dimensional model only assumes that the nonreacting CH[sub 3] group keeps a C[sub 3V] symmetry in reaction. The CH bond lengths in the nonreacting CH[sub 3] group were fixed in the study to reduce the number of degrees of freedom to seven. Our calculations reveal that it is very important to accurately deal with the umbrella motion of the CH[sub 3] group while studying this reaction. We investigated the effects of the fundamental vibrational excitations of CH[sub 4] on the reaction. Finally, we compare our rate constant for the ground rovibrational initial state with available experimental and other theoretical results. [ABSTRACT FROM AUTHOR]