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We propose, in this paper, a novel stochastic SIRS epidemic model to characterize the effect of uncertainty on the distribution of infectious disease, where the general incidence rate and Ornstein–Uhlenbeck process are also introduced to describe the complexity of disease transmission. First, the existence and uniqueness of the global nonnegative solution of our model is obtained, which is the basis for the discussion of the dynamical behavior of the model. And then, we derive a sufficient condition for exponential extinction of infectious diseases. Furthermore, through constructing a Lyapunov function and using Fatou's lemma, we obtain a sufficient criterion for the existence and ergodicity of a stationary distribution, which implies the persistence of the disease. In addition, the specific form of the density function of the model near the quasiendemic equilibrium is proposed by solving the corresponding Fokker–Planck equation and using some relevant algebraic equation theory. Finally, we explain the above theoretical results through some numerical simulations. [ABSTRACT FROM AUTHOR]

Synthesis of valuable chemicals from CO2 electroreduction in acidic media is highly desirable to overcome carbonation. However, suppressing the hydrogen evolution reaction in such proton-rich environments remains a considerable challenge. The current study demonstrates the use of a hollow fiber silver penetration electrode with hierarchical micro/nanostructures to enable CO2 reduction to CO in strong acids via balanced coordination of CO2 and K+/H+ supplies. Correspondingly, a CO faradaic efficiency of 95% is achieved at a partial current density as high as 4.3 A/cm2 in a pH = 1 solution of H2SO4 and KCl, sustaining 200 h of continuous electrolysis at a current density of 2 A/cm2 with over 85% single-pass conversion of CO2. The experimental results and density functional theory calculations suggest that the controllable CO2 feeding induced by the hollow fiber penetration configuration primarily coordinate the CO2/H+ balance on Ag active sites in strong acids, favoring CO2 activation and key intermediate *COOH formation, resulting in enhanced CO formation. Suppression of the competing H2 evolution reaction in CO2 electroreduction in strong acids remains a considerable challenge. Here, authors report a silver-based electrode that enables CO2 conversion to CO exceeding 85% at ampere-level current densities in pH = 1 electrolytes. [ABSTRACT FROM AUTHOR]

Biopsy is the recommended standard for pathological diagnosis of liver carcinoma. However, this method usually requires sectioning and staining, and well-trained pathologists to interpret tissue images. Here, we utilize Raman spectroscopy to study human hepatic tissue samples, developing and validating a workflow for in vitro and intraoperative pathological diagnosis of liver cancer. We distinguish carcinoma tissues from adjacent non-tumour tissues in a rapid, non-disruptive, and label-free manner by using Raman spectroscopy combined with deep learning, which is validated by tissue metabolomics. This technique allows for detailed pathological identification of the cancer tissues, including subtype, differentiation grade, and tumour stage. 2D/3D Raman images of unprocessed human tissue slices with submicrometric resolution are also acquired based on visualization of molecular composition, which could assist in tumour boundary recognition and clinicopathologic diagnosis. Lastly, the potential for a portable handheld Raman system is illustrated during surgery for real-time intraoperative human liver cancer diagnosis. Biopsy is recommended for definitive diagnosis of liver carcinoma, however, this process requires staining and expert pathologists to confirm diagnosis. Here, the authors employ a portable Raman spectroscopy system combined with deep learning to detect carcinoma from normal tissue in real time. [ABSTRACT FROM AUTHOR]

A fluorescent probe Pi with the excited-state intramolecular proton transfer (ESIPT) properties was synthesized and used to detect the phosgene in solution and gas phases. However, the detection mechanism of the fluorescent probe needs to be further studied. Herein, the density functional theory (DFT) and time-dependent density functional theory (TD-DFT) methods were adopted to explore the molecular structures and electronic spectra properties of probe and its product Pio after reacting with phosgene. Through analysis for molecular structure parameters and infrared vibrations accompanied with the hydrogen bond of Pi, it is confirmed that the intramolecular hydrogen bond of Pi is enhanced under light excitation, which illustrates the occurrence of ESIPT reaction combined with the scanned potential energy curves. It can be seen from the simulated spectra that Pi shows double fluorescence through ESIPT process, while the fluorescent product Pio exhibits the single fluorescence due to the disappearance of intramolecular hydrogen bond. Through the study on the structure and optical properties of Pi and Pio, it can be helpful to deeply understand the intrinsic mechanism of the detection of phosgene by the Pi molecule probe, which also supplies a reference to the further study about the fluorescence probe. [ABSTRACT FROM AUTHOR]

Exploring and synthesizing the compounds with stronger antioxidant activity have always been the goal of researchers. Herein, the substitution effects of the amino (NH2-) group with the excellent electron-donating ability in different positions on the antioxidant activity of Honokiol (Hon) were systematically explored by using the quantum chemistry calculation based on the density functional theory method. The three possible antioxidant mechanisms of Hon and its four NH2-substituted derivatives (Hon1–Hon4), containing the hydrogen atom transfer (HAT), single electron transfer followed by proton transfer (SET-PT), and sequential proton loss electron transfer (SPLET), were explored in depth considering the gas and solvent phases. In addition, the frontier molecular orbital energies, natural bond orbital (NBO) charge population, and global descriptive parameters were used to study their antioxidant activity. The results indicate that compared with the original molecule Hon, the NH2 substituents would have the stronger antioxidant activity. Moreover, the radical scavenging process of Hon and its derivatives has a disposition to the HAT and SPLET mechanisms in the gas and solvent phases, respectively. Meaningfully, owing to the lowest bond dissociation enthalpy and proton affinity values, Hon4 would show the most prominent antioxidant activity by comparison with the other compounds. In conclusion, this work will provide the purposeful reference for designing and synthesizing the antioxidants with more outstanding performance. [ABSTRACT FROM AUTHOR]

Gene-phenotype association prediction can be applied to reveal the inherited basis of human diseases and facilitate drug development. Gene-phenotype associations are related to complex biological processes and influenced by various factors, such as relationship between phenotypes and that among genes. While due to sparseness of curated gene-phenotype associations and lack of integrated analysis of the joint effect of multiple factors, existing applications are limited to prediction accuracy and potential gene-phenotype association detection. In this paper, we propose a novel method by exploiting weighted graph constraint learned from hierarchical structures of phenotype data and group prior information among genes by inheriting advantages of Non-negative Matrix Factorization (NMF), called Weighted Graph Constraint and Group Centric Non-negative Matrix Factorization (GC2NMF). Specifically, first we introduce the depth of parent-child relationships between two adjacent phenotypes in hierarchical phenotypic data as weighted graph constraint for a better phenotype understanding. Second, we utilize intra-group correlation among genes in a gene group as group constraint for gene understanding. Such information provides us with the intuition that genes in a group probably result in similar phenotypes. The model not only allows us to achieve a high-grade prediction performance, but also helps us to learn interpretable representation of genes and phenotypes simultaneously to facilitate future biological analysis. Experimental results on biological gene-phenotype association datasets of mouse and human demonstrate that GC2NMF can obtain superior prediction accuracy and good understandability for biological explanation over other state-of-the-arts methods. [ABSTRACT FROM AUTHOR]

On September 21, 2015, the National Transportation Safety Board responded to a petroleum leak from a transmission pipeline in Centreville, VA. A small through crack was found leaking at a dent on the underside of the pipe, located away from any welds. The investigation found that corrosion fatigue could initiate at small dents, typically caused by impingement. While top-side dents from excavation and servicing have well-been documented and regulated, bottom-side dents, deemed acceptable per regulations, were found to be susceptible to stress corrosion and fatigue cracking. This investigation explored multiple and fundamental aspects of cracking in steel pipe dents, including nondestructive inspection, electron microscopy, finite element modeling, and long-term cyclic loading tests to characterize the cause of this pipeline accident. [ABSTRACT FROM AUTHOR]

A mixed-species aggregation refers to a group of individuals of different species attracted together by an environmental factor. Although they are traditionally considered not as structured as moving mixed-species groups, the composition and organization of aggregations can be influenced both by competition and by information flow between species. Frugivorous birds, for example, might move towards vocalizations of other species as cues to resources. If they differentially respond to a combination of other species' vocalizations, an indication of a generalist fruiting tree, this could be a mechanism that creates nested structure in seed dispersal networks. We used both observational and experimental methods to study a community of frugivores in southwest China. Although the foraging niches of the birds highly overlapped, little interspecific aggression was found, suggesting a superabundant food resource. Birds were more attracted to playback of mass-fruiting trees, recorded when they were fruiting, than recordings made when those same trees were not fruiting. We compared attraction to the vocalizations of (a) an insectivorous species, (b, c, d) three species of frugivores, each presented separately, and (e) a combination of the frugivores in which their vocalizations were repeated sequentially. Response of heterospecific frugivores to the combination tape was significantly higher than to the insectivorous control, and tended ( P = 0.068) to be higher than response to the frugivores. We suggest that this represents an indication that birds can use the diversity of vocalizations in a tree as a cue to understand the community of trees they interact with, as well as the community of birds. Significance statement: To our knowledge, although now used frequently with mixed-species bird flocks, playback has not been used to explore whether frugivorous birds could use heterospecific vocalizations to find fruit. We present the results of a simple, realistic experiment that shows that respondents approach trees in which birds, the majority of which are heterospecifics, are vocalizing. The results from a more complicated, controlled experiment suggest that birds may preferentially be attracted to a combination of frugivores' sounds. We argue these results have relevance to the structure of seed dispersal networks, although we cannot demonstrate that specialist birds hone in on generalist trees by cuing on heterospecific vocalizations because of the rarity of specialists in our system. [ABSTRACT FROM AUTHOR]

In this paper, a cohesive finite element method (FEM) is proposed for a quasi-continuum (QC), i.e. a continuum model that utilizes the information of underlying atomistic microstructures. Most cohesive laws used in conventional cohesive FEMs are based on either empirical or idealized constitutive models that do not accurately reflect the actual lattice structures. The cohesive quasi-continuum finite element method, or cohesive QC-FEM in short, is a step forward in the sense that: (1) the cohesive relation between interface traction and displacement opening is now obtained based on atomistic potentials along the interface, rather than empirical assumptions; (2) it allows the local QC method to simulate certain inhomogeneous deformation patterns. To this end, we introduce an interface or discontinuous Cauchy–Born rule so the interfacial cohesive laws are consistent with the surface separation kinematics as well as the atomistically enriched hyperelasticity of the solid. Therefore, one can simulate inhomogeneous or discontinuous displacement fields by using a simple local QC model. A numerical example of a screw dislocation propagation has been carried out to demonstrate the validity, efficiency, and versatility of the method. [ABSTRACT FROM AUTHOR]

Standard deviations for vertical velocity and scalar quantities, such as temperature, T, and specific humidity, q, were analyzed on the basis of Monin-Obukhov (M-O) similarity theory in the atmospheric surface layer. The correlation coefficient between scalar quantities T and q, ∣R$\_Tq$∣|, was derived from the similarity functions and can be expressed as the ratio of B$\_T$/B$\_q$ (B$\_T$≤ B$\_q$), where parameter B is the value of the normalized standard deviation of any scalar quantity at neutral conditions. [ABSTRACT FROM AUTHOR]

A method for the independent evaluation of mixed-layer (ML) height, zi, has been proposed. The ML height is determined by the functional relationships zi = 0.75 z/nv max or 0.53 z/nu max in which, z is a measuring height; nv max and nu max are normalized peak frequencies of lateral velocity component, v, and longitudinal velocity component, u, spectra at height z in the surface layer respectively. Using Doppler sodar data, the technique was shown to be feasible; it is easy to apply to micro-meteorological field experiments and works even for the ML top above the range of the sodar. [ABSTRACT FROM AUTHOR]