Role of ripples in altering the electronic and chemical properties of graphene.

Ripples of graphene are known to manipulate electronic and hydrogenation properties of graphitic materials. More detailed work is needed to elucidate the structure-property relationship of these systems. In this work, the density functional theory is used to compute the energy and electronic structure of the graphene models with respect to variable curvatures and hydrogen adsorption sites. The magnitude of finite bandgap opening depends on the orientation of ripples, and the hydrogen adsorption energy depends on the local curvature of graphene. An adsorbed hydrogen alters the local curvature, resulting in relatively weakened adsorption on the neighboring three sites, which gives a rationale to experimentally observed dynamic equilibrium stoichiometry (H:C = 1:4) of hydrogenated graphene. The surface diffusion transition state energy of adsorbed hydrogen is computed, which suggests that the Eley-Rideal surface recombination mechanism may be important to establish the dynamic equilibrium, instead of the commonly assumed Langmuir-Hinshelwood mechanism.

Aedes albopictus Autophagy-Related Gene 8 (AaAtg8) Is Required to Confer Anti-Bacterial Gut Immunity.

Autophagy is an important process by which pathogens and damaged or unused organelles are eliminated. The role of autophagy in development and the immune response to pathogens is well established. Autophagy-related protein 8 (Atg8) is involved in the formation of the autophagosome and, with the help of the serine protease Atg4, mediates the delivery of both vesicles and the autophagosome to the vacuole. Here, we cloned the Aedes albopictus autophagy-related protein 8 (AaAtg8) gene and characterized its role in the innate immunity of the mosquito against microbial infections. AaAtg8 is comprised of an open reading frame (ORF) region of 357 bp encoding a polypeptide of 118 amino acid residues. A domain analysis of AaAtg8 revealed an Atg8 ubiquitin-like domain, Atg7/Atg4 interaction sites, and peptide binding sites. The AaAtg8 mRNA expression was high in the Malpighian tubules and heads of both sugar-fed and blood-fed adult female mosquitoes. The expression level of AaAtg8 mRNA increased in the midgut and abdominal carcass following being challenged with Listeria monocytogenes. To investigate the role of AaAtg8 in the innate immune responses of Ae. albopictus, AaAtg8 gene-silenced adult mosquitoes were challenged by injection or by being fed microorganisms in blood. High mortality rates were observed in mosquitoes in which AaAtg8 was silenced after challenges of microorganisms to the host by blood feeding. This suggests that Atg8-autophagy plays a critical role in the gut immunity in Ae. albopictus.

IKKγ/NEMO Is Required to Confer Antimicrobial Innate Immune Responses in the Yellow Mealworm, Tenebrio Molitor.

IKKγ/NEMO is the regulatory subunit of the IκB kinase (IKK) complex, which regulates the NF-κB signaling pathway. Within the IKK complex, IKKγ/NEMO is the non-catalytic subunit, whereas IKKα and IKKß are the structurally related catalytic subunits. In this study, TmIKKγ was screened from the Tenebrio molitor RNA-Seq database and functionally characterized using RNAi screening for its role in regulating T. molitor antimicrobial peptide (AMP) genes after microbial challenges. The TmIKKγ transcript is 1521 bp that putatively encodes a polypeptide of 506 amino acid residues. TmIKKγ contains a NF-κB essential modulator (NEMO) and a leucine zipper domain of coiled coil region 2 (LZCC2). A phylogenetic analysis confirmed its homology to the red flour beetle, Tribolium castaneum IKKγ (TcIKKγ). The expression of TmIKKγ mRNA showed that it might function in diverse tissues of the insect, with a higher expression in the hemocytes and the fat body of the late-instar larvae. TmIKKγ mRNA expression was induced by Escherichia coli, Staphylococcus aureus, and Candida albicans challenges in the whole larvae and in tissues such as the hemocytes, gut and fat body. The knockdown of TmIKKγ mRNA significantly reduced the survival of the larvae after microbial challenges. Furthermore, we investigated the tissue-specific induction patterns of fourteen T. molitor AMP genes in TmIKKγ mRNA-silenced individuals after microbial challenges. In general, the mRNA expression of TmTenecin1, -2, and -4; TmDefensin1 and -2; TmColeoptericin1 and 2; and TmAttacin1a, 1b, and 2 were found to be downregulated in the hemocytes, gut, and fat body tissues in the TmIKKγ-silenced individuals after microbial challenges. Under similar conditions, TmRelish (NF-κB transcription factor) mRNA was also found to be downregulated. Thus, TmIKKγ is an important factor in the antimicrobial innate immune response of T. molitor.

Uncovering the Thermo-Kinetic Origins of Phase Ordering in Mixed-Valence Antimony Tetroxide by First-Principles Modeling.

Phase ordering in the mixed-valence oxide Sb2O4 has been examined by density functional theory (DFT) calculations. We find that the ground-state total energies of the two phases (α and ß) are almost degenerate and are highly sensitive to the choice of the approximation to the exchange correlation (xc) functional used in our calculations. Interestingly, with the inclusion of the zero-point energy corrections, the α phase is predicted to be the ground state polymorph for most xc functionals used. We also illustrate the pronounced stereochemical activity of Sb in these polymorphs of Sb2O4, setting an exception to the Keve and Skapski rule. Here, we find that the actual bonding in the α phase is more asymmetric, while the anomalous stability of the ß phase could be rationalized from kinetic considerations. We find a non-negligible activation barrier for this α-ß phase transition, and the presence of a saddle point (ß phase) supports the separation of Sb(III) over a continuous phase transition, as observed in experiments.

Quality of medical service, patient satisfaction and loyalty with a focus on interpersonal-based medical service encounters and treatment effectiveness: a cross-sectional multicenter study of complementary and alternative medicine (CAM) hospitals.

BACKGROUND: Treatment effectiveness holds considerable importance in the association between service quality and satisfaction in medical service studies. While complementary and alternative medicine (CAM) use grows more prominent, comprehensive evaluations of the quality of medical service at CAM-oriented hospitals are scarce. This study assesses the quality of medical services provided at a CAM-oriented hospital of Korean medicine using the service encounter system approach and analyzes the influence of treatment effectiveness on patient loyalty. METHODS: A survey study using one-on-one interviews was conducted using a cross-sectional design in outpatients visiting one of fifteen Korean medicine facilities located throughout Korea. A total of 880 surveys were completed from June to July, 2014, and 728 surveys were included in the final analysis after excluding incomplete or incorrect questionnaires. The reliability and validity of the surveys was confirmed using Cronbach's alpha coefficient and confirmatory factor analysis, and a structural equation modeling analysis was performed to verify causality and association between factors (quality of medical service, treatment effectiveness, patient satisfaction, and intent to revisit). RESULTS: The measured factors of physician performance and quality of service procedures had a positive effect on treatment effectiveness. The impression of the facilities and environment directly impacted satisfaction rates for interpersonal-based medical service encounters, while treatment effectiveness positively affected satisfaction regarding quality of medical service. However, treatment effectiveness had a more significant effect on satisfaction compared to facilities and environment, and it indirectly affected satisfaction and directly influenced intent to revisit. Treatment effectiveness and satisfaction both positively influenced intent to revisit. CONCLUSIONS: The importance of treatment effectiveness should be recognized when examining quality of medical services, and we hope that these findings may contribute to future studies.

Anharmonicity in the High-Temperature Cmcm Phase of SnSe: Soft Modes and Three-Phonon Interactions.

The layered semiconductor SnSe is one of the highest-performing thermoelectric materials known. We demonstrate, through a first-principles lattice-dynamics study, that the high-temperature Cmcm phase is a dynamic average over lower-symmetry minima separated by very small energetic barriers. Compared to the low-temperature Pnma phase, the Cmcm phase displays a phonon softening and enhanced three-phonon scattering, leading to an anharmonic damping of the low-frequency modes and hence the thermal transport. We develop a renormalization scheme to quantify the effect of the soft modes on the calculated properties, and confirm that the anharmonicity is an inherent feature of the Cmcm phase. These results suggest a design concept for thermal insulators and thermoelectric materials, based on displacive instabilities, and highlight the power of lattice-dynamics calculations for materials characterization.

Unraveling the origins of conduction band valley degeneracies in Mg2Si(1-x)Sn(x) thermoelectrics.

To better understand the thermoelectric efficiency of the Mg-based thermoelectrics, using hybrid density-functional theory, we study the microscopic origins of valley degeneracies in the conduction band of the solid solution Mg2Si(1-x)Sn(x) and its constituent components--namely, Mg2Si and Mg2Sn. In the solid solution of Mg2Si(1-x)Sn(x), the sublattices are expected to undergo either tensile or compressive strain in the light of Vegard's law. Interestingly, we find both tensile strain of Mg2Si and compressive strain of Mg2Sn enhance the conduction band valley degeneracy. We suggest that the optimal sublattice strain as one of the origins of the enhanced Seebeck coefficient in the Mg2Si(1-x)Sn(x) system. In order to visualize the enhanced band valley degeneracy at elevated temperatures, the ground state eigenvalues and weights are projected by convolution functions that account for high temperature effects. Our results provide theoretical evidences for the role of sublattice strain in the band valley degeneracy observed in Mg2Si(1-x)Sn(x).

Effect of gold subsurface layer on the surface activity and segregation in Pt/Au/Pt3M (where M = 3d transition metals) alloy catalyst from first-principles.

The effect of a subsurface hetero layer (thin gold) on the activity and stability of Pt skin surface in Pt3M system (M = 3d transition metals) is investigated using the spin-polarized density functional theory calculation. First, we find that the heterometallic interaction between the Pt skin surface and the gold subsurface in Pt/Au/Pt3M system can significantly modify the electronic structure of the Pt skin surface. In particular, the local density of states projected onto the d states of Pt skin surface near the Fermi level is drastically decreased compared to the Pt/Pt/Pt3M case, leading to the reduction of the oxygen binding strength of the Pt skin surface. This modification is related to the increase of surface charge polarization of outmost Pt skin atoms by the electron transfer from the gold subsurface atoms. Furthermore, a subsurface gold layer is found to cast the energetic barrier to the segregation loss of metal atoms from the bulk (inside) region, which can enhance the durability of Pt3M based catalytic system in oxygen reduction condition at fuel cell devices. This study highlights that a gold subsurface hetero layer can provide an additional mean to tune the surface activity toward oxygen species and in turn the oxygen reduction reaction, where the utilization of geometric strain already reaches its practical limit.

Re-visiting the O/Cu(111) system--when metastable surface oxides could become an issue!

Surface oxidation processes are crucial for the functionality of Cu-based catalytic systems used for methanol synthesis, partial oxidation of methanol or the water-gas shift reaction. We assess the stability and population of the "8"-structure, a [formula, see text:] oxide phase, on the Cu(111) surface. This structure has been observed in X-ray photoelectron spectroscopy and low-energy electron diffraction experiments as a Cu(111) surface reconstruction that can be induced by a hyperthermal oxygen molecular beam. Using density-functional theory calculations in combination with ab initio atomistic thermodynamics and Boltzmann statistical mechanics, we find that the proposed oxide superstructure is indeed metastable and that the population of the "8"-structure is competitive with the known "29" and "44" oxide film structures on Cu(111). We show that the configuration of O and Cu atoms in the first and second layers of the "8"-structure closely resembles the arrangement of atoms in the first two layers of Cu2O(110), where the atoms in the "8"-structure are more constricted. Cu2O(110) has been suggested in the literature as the most active low index facet for reactions such as water splitting under light illumination. If the "8"-structure were to form during a catalytic process, it is therefore likely to be one of the reactive phases.

Correction: Investigation of craquelure patterns in oil paintings using precise 3D morphological analysis for art authentication.

[This corrects the article DOI: 10.1371/journal.pone.0272078.].

IKKß regulates antimicrobial innate immune responses in the yellow mealworm, Tenebrio molitor.

Toll and IMD pathways regulate antimicrobial innate immune responses in insect model systems. The transcriptional activation of antimicrobial peptides (AMPs) confers humoral immunity in the host against invaded pathogens. The IKK kinase complex (IKKα, IKKß, and the regulatory subunit IKKγ/NEMO) centrally regulates the NF-κB response to various stimuli. It triggers an appropriate antimicrobial immune response in the host. In this study, a TmIKKß (or TmIrd5) homolog was screened from the RNA-seq database of the coleopteran beetle, Tenebrio molitor. A single exon characterizes the TmIKKß gene, and the open reading frame (ORF) comprises of 2112 bp that putatively encodes a polypeptide of 703 amino acid residues. TmIKKß contains a serine/threonine kinase domain and is phylogenetically close to Tribolium castaneum IKKß homolog (TcIKKß). TmIKKß transcripts were highly expressed in the early pupal (P1) and adult (A5) stages. Among the tissues, TmIKKß showed higher expression in the integument of the last instar larvae and the fat body and hemocytes of 5-day-old adults. TmIKKß mRNA was upregulated post-E. coli challenge to the host. Moreover, RNAi-based TmIKKß mRNA silencing increased host larvae' susceptibility against E. coli, S. aureus and C. albicans. TmIKKß RNAi in the fat body led to a downregulation in mRNA expression of ten out of fourteen AMP genes, including TmTenecin1, -2, and -4; TmDefensin, and -like; TmColeoptericinA, and -B; and TmAttacin1a, -1b, and -2, suggesting the requirement of the gene in antimicrobial innate immune responses. Further, a decrease in the mRNA expression of NF-κB factors such as TmRelish, TmDorsal1, and TmDorsal2 in the fat body of T. molitor larvae was observed post-microorganisms challenge. Thus, TmIKKß regulates antimicrobial innate immune responses in T. molitor.

A first-principles study of ultrathin nanofilms of MgO-supported TiN.

As a first step towards a microscopic understanding of supported ultrathin nanofilms of TiN, we present state-of-the-art density-functional theory (DFT) calculations to investigate the interfacial properties of the TiN/MgO system as a function of film thickness. Optimized atomic geometries, energetics, and analysis of the electronic structure of the TiN/MgO systems are reported. In particular, we find that the work function of 1 ML of TiN(100) on MgO(100) exhibits a significant decrease, rationalized by the large surface dipole moment formation due to the changes in charge densities at the interface of this system. This decrease in the work function of TiN/MgO systems (as compared to pristine MgO(100) surface) could well benefit their application in metal-oxide-semiconductor devices as an ideal gate-stack material.

Investigation of craquelure patterns in oil paintings using precise 3D morphological analysis for art authentication.

The development of scientific technology for art authentication has elicited multidimensional evidence to distinguish forgeries from original artwork. Here, we analyzed the three-dimensional morphology of cracks that contain information, such as the painting features of artworks, using optical coherence tomography. The forgeries were produced by an expert from original oil paintings with cracks that occur owing to paint drying, canvas aging, and physical damage. Parameters, such as shape, width, and depth, were compared based on the cross-sectional images of the original and fake cracks. The original cracks were rectangular and inverted, but the fake cracks were relatively simple inverted triangles. The original cracks were as deep as the thickness of the upper layer and mostly were "thin/deep" or "wide/shallow". The fake cracks were observed to be "'thin/shallow" or "wide/deep". This study aims to improve the understanding of crack characteristics and promote the development of techniques for determining art authenticity.

TmIKKε Is Required to Confer Protection Against Gram-Negative Bacteria, E. coli by the Regulation of Antimicrobial Peptide Production in the Tenebrio molitor Fat Body.

The inhibitor of nuclear factor-kappa B (NF-κB) kinase (IKK) is the core regulator of the NF-κB pathway against pathogenic invasion in vertebrates or invertebrates. IKKß, -ε and -γ have pivotal roles in the Toll and immune deficiency (IMD) pathways. In this study, a homolog of IKKε (TmIKKε) was identified from Tenebrio molitor RNA sequence database and functionally characterized for its role in regulating immune signaling pathways in insects. The TmIKKε gene is characterized by two exons and one intron comprising an open reading frame (ORF) of 2,196 bp that putatively encodes a polypeptide of 731 amino acid residues. TmIKKε contains a serine/threonine protein kinases catalytic domain. Phylogenetic analysis established the close homology of TmIKKε to Tribolium castaneum IKKε (TcIKKε) and its proximity with other IKK-related kinases. The expression of TmIKKε mRNA was elevated in the gut, integument, and hemocytes of the last-instar larva and the fat body, Malpighian tubules, and testis of 5-day-old adults. TmIKKε expression was significantly induced by Escherichia coli, Staphylococcus aureus, and Candida albicans challenge in whole larvae and tissues, such as hemocytes, gut, and fat body. The knockdown of the TmIKKε messenger RNA (mRNA) expression significantly reduced the survival of the larvae against microbial challenges. Further, we investigated the induction patterns of 14 T. molitor antimicrobial peptides (AMPs) genes in TmIKKε gene-silencing model after microbial challenges. While in hemocytes, the transcriptional regulation of most AMPs was negatively regulated in the gut and fat body tissue of T. molitor, AMPs, such as TmTenecin 1, TmTenecin 4, TmDefensin, TmColeoptericin A, TmColeoptericin B, TmAttacin 1a, and TmAttacin 2, were positively regulated in TmIKKε-silenced individuals after microbial challenge. Collectively, the results implicate TmIKKε as an important factor in antimicrobial innate immune responses in T. molitor.

Author Correction: TmRelish is required for regulating the antimicrobial responses to Escherichia coli and Staphylococcus aureus in Tenebrio molitor.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

TmRelish is required for regulating the antimicrobial responses to Escherichia coli and Staphylococcus aureus in Tenebrio molitor.

Relish, a transcription factor, is a critical downstream component of the immune deficiency (Imd) pathway and regulates host defense against bacterial infection by mediating antimicrobial peptide (AMP) synthesis. Understanding the immunological function of the mealworm beetle, Tenebrio molitor Relish (TmRelish) will be instructive in understanding insect immunity. In the present study, full-length ORF of TmRelish was retrieved from T. molitor-expressed sequence tags and RNA-seq database. The predicted TmRelish amino acid sequence contained an N-terminal Rel-homology domain; an Ig-like, plexin, and transcription factor domain; ankyrin repeat motifs; a nuclear localization signal; and a C-terminal death domain and shared the highly conserved structure of the Relish proteins of other insect species. TmRelish mRNA was detected in all developmental stages of the insect; however, the highest levels were detected in the larval gut tissue and adult hemocytes. TmRelish mRNA level was upregulated in the fat body, hemocyte, and gut tissue 9 h after infection of T. molitor larvae by the gram-negative bacteria, Escherichia coli. Furthermore, TmRelish knockdown led to significantly higher mortality of the E. coli-infected larvae, and significantly lower mortality of larvae infected with Staphylococcus aureus or Candida albicans. To elucidate the possible cause of mortality, we measured AMP transcription in the fat body, hemocytes, gut, and Malpighian tubules (MTs) of T. molitor larvae. TmRelish knockdown suppressed the expression of nine AMP genes in the larval fat body and gut tissue during E. coli infection, suggesting that TmRelish positively regulates AMP expression in both immune-related tissues, in response to E. coli challenge. Furthermore, negative regulation of some AMPs by TmRelish in the MTs, gut and hemocytes in response to C. albicans infection suggests a crosstalk between the Toll and Imd pathways.

Regulation of the expression of nine antimicrobial peptide genes by TmIMD confers resistance against Gram-negative bacteria.

Immune deficiency (IMD) is a death domain-containing protein that is essential for the IMD/NF-κB humoral and epithelial immune responses to Gram-negative bacteria and viruses in insects. In the immune signaling cascade, IMD is recruited together with FADD and the caspase DREDD after the mobilization of PGRP receptors. Activated IMD regulates the expression of effector antimicrobial peptides (AMP) that protect against invading microorganisms. To date, most studies of the IMD pathway, and the IMD gene in particular, have been restricted to Drosophila; few similar studies have been conducted in other model insects. Herein, we cloned and functionally characterized an IMD homolog from the mealworm beetle Tenebrio molitor (TmIMD) and studied its role in host survival in the context of pathogenic infections. Phylogenetic analysis revealed the conserved caspase cleavage site and inhibitor of apoptosis (IAP)-binding motif (IBM). TmIMD expression was high in the hemocytes and Malpighian tubules of Tenebrio late-instar larvae and adults. At 3 and 6 hours' post-infection with Escherichia coli, Staphylococcus aureus, or Candida albicans, TmIMD expression significantly increased compared with mock-infected controls. Knockdown of the TmIMD transcript by RNAi significantly reduced host resistance to the Gram-negative bacterium E. coli and fungus C. albicans in a survival assay. Strikingly, the expression of nine T. molitor AMPs (TmTenecin1, TmTenecin2, TmTenecin4, TmDefensin2, TmColeoptericin1, TmColeoptericin2, TmAttacin1a, TmAttacin1b, and TmAttacin2) showed significant downregulation in TmIMD knockdown larvae challenged with E. coli. These results suggest that TmIMD is required to confer humoral immunity against the Gram-negative bacteria, E. coli by inducing the expression of critical transcripts that encode AMPs.

TmToll-7 Plays a Crucial Role in Innate Immune Responses Against Gram-Negative Bacteria by Regulating 5 AMP Genes in Tenebrio molitor.

Although it is known that the Drosophila Toll-7 receptor plays a critical role in antiviral autophagy, its function in other insects has not yet been reported. Here, we have identified a Toll-like receptor 7 gene, TmToll-7, in the coleopteran insect T. molitor and examined its potential role in antibacterial and antifungal immunity. We showed that TmToll-7 expression was significantly induced in larvae 6 h after infection with Escherichia coli and Staphylococcus aureus and 9 h after infection with Candida albicans. However, even though TmToll-7 was induced by all three pathogens, we found that TmToll-7 knockdown significantly reduced larval survival to E. coli, but not to S. aureus, and C. albicans infections. To understand the reasons for this difference, we examined the effects of TmToll-7 knockdown on antimicrobial peptide (AMP) gene expression and found a significant reduction of E. coli-induced expression of AMP genes such as TmTenecin-1, TmDefensin-1, TmDefensin-2, TmColeoptericin-1, and TmAttacin-2. Furthermore, TmToll-7 knockdown larvae infected with E. coli showed significantly higher bacterial growth in the hemolymph compared to control larvae treated with Vermilion dsRNA. Taken together, our results suggest that TmToll-7 plays an important role in regulating the immune response of T. molitor to E. coli.

Pantropical climate interactions.

The El Niño-Southern Oscillation (ENSO), which originates in the Pacific, is the strongest and most well-known mode of tropical climate variability. Its reach is global, and it can force climate variations of the tropical Atlantic and Indian Oceans by perturbing the global atmospheric circulation. Less appreciated is how the tropical Atlantic and Indian Oceans affect the Pacific. Especially noteworthy is the multidecadal Atlantic warming that began in the late 1990s, because recent research suggests that it has influenced Indo-Pacific climate, the character of the ENSO cycle, and the hiatus in global surface warming. Discovery of these pantropical interactions provides a pathway forward for improving predictions of climate variability in the current climate and for refining projections of future climate under different anthropogenic forcing scenarios.

Molecular Cloning and Effects of Tm14-3-3ζ-Silencing on Larval Survivability Against E. coli and C. albicans in Tenebrio molitor.

The 14-3-3 family of proteins performs key regulatory functions in phosphorylation-dependent signaling pathways including cell survival and proliferation, apoptosis, regulation of chromatin structure and autophagy. In this study, the zeta isoform of 14-3-3 proteins (designated as Tm14-3-3ζ) was identified from the expressed sequence tags (ESTs) and RNA sequencing (RNA-Seq) database of the coleopteran pest, Tenebrio molitor. Tm14-3-3ζ messenger RNA (mRNA) is expressed at higher levels in the immune organs of the larval and adult stages of the insect and exhibit almost five-fold induction within 3 h post-infection of the larvae with Escherichia coli and Candida albicans. To investigate the biological function of Tm14-3-3ζ, a peptide-based Tm14-3-3ζ polyclonal antibody was generated in rabbit and the specificity was confirmed using Western blot analysis. Immunostaining and confocal microscopic analyses indicate that Tm14-3-3ζ is mainly expressed in the membranes of midgut epithelial cells, the nuclei of fat body and the cytosol of hemocytes. Gene silencing of Tm14-3-3ζ increases mortality of the larvae at 7 days post-infection with E. coli and C. albicans. Our findings demonstrate that 14-3-3ζ in T. molitor is essential in the host defense mechanisms against bacteria and fungi.