Exceptions to the rule: When does resistance evolution not undermine antibiotic therapy in human bacterial infections?

The use of antibiotics to treat bacterial infections often imposes strong selection for antibiotic resistance. However, the prevalence of antibiotic resistance varies greatly across different combinations of pathogens and drugs. What underlies this variation? Systematic reviews, meta-analyses, and literature surveys capable of integrating data across many studies have tried to answer this question, but the vast majority of these studies have focused only on cases where resistance is common or problematic.

Low Lattice Thermal Conductivity in a Wider Temperature Range for Biphasic-Quaternary (Ti,V)CoSb Half-Heusler Alloys.

Intrinsically high lattice thermal conductivity has remained a major bottleneck for achieving a high thermoelectric figure of merit () in state-of-the-art ternary half-Heusler (HH) alloys. In this work, we report a stable n-type biphasic-quaternary (Ti,V)CoSb HH alloy with a low lattice thermal conductivity κ ≈ 2 W m K within a wide temperature range (300-873 K), which is comparable to the reported nanostructured HH alloys. A solid-state transformation driven by spinodal decomposition upon annealing is observed in TiVCoSb HH alloy, which remarkably enhances phonon scattering, while electrical properties correlate well with the altering electronic band structure and valence electron count (VEC).

Disorder in the Human Skp1 Structure is the Key to its Adaptability to Bind Many Different Proteins in the SCF Complex Assembly.

Skp1(S-phase kinase-associated protein 1 - Homo sapiens) is an adapter protein of the SCF(Skp1-Cullin1-Fbox) complex, which links the constant components (Cul1-RBX) and the variable receptor (F-box proteins) in Ubiquitin E3 ligase. It is intriguing how Skp1 can recognise and bind to a variety of structurally different F-box proteins. For practical reasons, previous efforts have used truncated Skp1, and thus it has not been possible to track the crucial aspects of the substrate recognition process.

Revealing Na-segregation at the Si/Graphene Interface and Its Implications toward the Na-storage Behavior of Si-Based Electrodes.

The feasibility of reversible alloying of Na with Si has led to Si being considered as a potential anode material for the upcoming Na-ion battery system. However, Si exhibits useful Na-storage capacity and associated electrochemical cyclic stability only in the presence of graphene-based interlayers/additives. Despite this, no knowledge exists concerning the characteristics/phenomena at the Si/graphene interface and the possible influence of the same toward Na-storage behavior/performance.

Self-Doping for Synergistically Tuning the Electronic and Thermal Transport Coefficients in n-Type Half-Heuslers.

Ternary intermetallic half-Heusler (HH) compounds (XYZ) with 18 valence electron count, namely, ZrCoSb, ZrNiSn, and ZrPdSn, have revealed promising thermoelectric properties. Exemplarily, it has been experimentally observed that a slight change in the content of Y site atoms (by ∼3-12.5% i.

DNA Content Variation and SNP Diversity Within a Single Population of Asexual Snails.

A growing body of research suggests that many clonal populations maintain genetic diversity even without occasional sexual reproduction. The purpose of our study was to document variation in single-nucleotide polymorphism (SNP) diversity, DNA content, and pathogen susceptibility in clonal lineages of the New Zealand freshwater snail, Potamopyrgus antipodarum. We studied snails that were collected from multiple field sites around a single lake (Lake Alexandrina), as well as isofemale clonal lineages that had been isolated and maintained in the laboratory.

Ultralow Lattice Thermal Conductivity at Room Temperature in Cu TiSe.

Ultralow thermal conductivity draws great attention in a variety of fields of applications such as thermoelectrics and thermal barrier coatings. Herein, the crystal structure and transport properties of Cu TiSe are reported. Cu TiSe is a unique example of a non-toxic and low-cost material that exhibits a lattice ultra-low thermal conductivity of 0.

Evolutionary consequences of feedbacks between within-host competition and disease control.

Lay Summary: Competition often occurs among diverse parasites within a single host, but control efforts could change its strength. We examined how the interplay between competition and control could shape the evolution of parasite traits like drug resistance and disease severity.

Deviation from guest dominated glass like lattice dynamics in prototypical ternary BaNi Ge[Formula: see text] clathrates.

Intermetallic guest filled clathrate cages have been identified as promising materials for thermoelectric applications. The structure, electronic structure, and phonon dynamics of type-I Ba filled Ni substituted Ge clathrates have been explored using density-functional theory. The formation energy of type-I BaNi Ge[Formula: see text] clathrates with y  vacancies [Formula: see text] in their framework is calculated as a function of concentration of Ni substitution x.

Evolution of increased virulence is associated with decreased spite in the insect-pathogenic bacterium Xenorhabdus nematophila.

Disease virulence may be strongly influenced by social interactions among pathogens, both during the time course of an infection and evolutionarily. Here, we examine how spiteful bacteriocin production in the insect-pathogenic bacterium Xenorhabdus nematophila is evolutionarily linked to its virulence. We expected a negative correlation between virulence and spite owing to their inverse correlations with growth.

Compositional Tailoring for Realizing High Thermoelectric Performance in Hafnium-Free n-Type ZrNiSn Half-Heusler Alloys.

Compositional tailoring enables fine-tuning of thermoelectric (TE) transport parameters by synergistic modulation of electronic and vibrational properties. In the present work, the aspects of compositionally tailored defects have been explored in ZrNiSn-based half-Heusler (HH) TE materials to achieve high TE performance and cost effectiveness in n-type Hf-free HH alloys. In off-stoichiometric Ni-rich ZrNiSn alloys in a low Ni doping limit ( < 0.

Suppression of bacteriocin resistance using live, heterospecific competitors.

Rapidly spreading antibiotic resistance has led to the need for novel alternatives and sustainable strategies for antimicrobial use. Bacteriocins are a class of proteinaceous anticompetitor toxins under consideration as novel therapeutic agents. However, bacteriocins, like other antimicrobial agents, are susceptible to resistance evolution and will require the development of sustainable strategies to prevent or decelerate the evolution of resistance.

Plastic responses to competition: Does bacteriocin production increase in the presence of nonself competitors?

Anticompetitor traits such as the production of allelopathic toxins can confer significant competitive benefits but are often costly to produce. Evolution of these traits may be facilitated by environment-specific induction; however, the extent to which costly anticompetitor traits are induced by competitors is not well explored. Here, we addressed this question using bacteriocins, which are highly specific, proteinaceous anticompetitor toxins, produced by most lineages of bacteria and archaea.

The origin of diverse lattice dynamics in the graphene family.

We employ first principles based density functional theory calculations to explore the lattice dynamics of members of the graphene family. We explore the changes observed in the lattice thermal conductivity via adopting physical models for estimating phonon lifetimes. This allows us to establish a connection between the parameters such as group velocity, Grüneisen parameter, and Debye temperature of the acoustic phonon modes and the lattice thermal conductivity.

Early emergence of altered 5-HT receptor-evoked behavior, neural activation and gene expression following maternal separation.

The early stress of Maternal Separation (MS) contributes to the establishment of adult psychopathology. The serotonergic (5-HT) system is implicated during this temporal window in mediating the development of mood-related behaviors. MS is reported to evoke altered 5-HT receptor function in adulthood.

Formation of Vacancies in Si- and Ge-based Clathrates: Role of Electron Localization and Symmetry Breaking.

The formation of framework vacancies in Si- and Ge-based type-I clathrates is studied using density-functional theory as a function of filling the cages with K and Ba atoms. Our analysis reveals the relevance of structural disorder, geometric relaxation, and electronic saturation as well as vibrational and configurational entropy. In the Si clathrates, we find that vacancies are unstable, but very differently, in Ge clathrates, up to three vacancies per unit cell can be stabilized.

Coevolutionary interactions with parasites constrain the spread of self-fertilization into outcrossing host populations.

Given the cost of sex, outcrossing populations should be susceptible to invasion and replacement by self-fertilization or parthenogenesis. However, biparental sex is common in nature, suggesting that cross-fertilization has substantial short-term benefits. The Red Queen hypothesis (RQH) suggests that coevolution with parasites can generate persistent selection favoring both recombination and outcrossing in host populations.

Exploring N-Rich Phases in Li(x)N(y) Clusters for Hydrogen Storage at Nanoscale.

We have performed cascade genetic algorithm and ab initio atomistic thermodynamics under the framework of first-principles-based hybrid density functional theory to study the (meta-)stability of a wide range of Li(x)N(y) clusters. We found that hybrid xc-functional is essential to address this problem as a local/semilocal functional simply fails even to predict a qualitative prediction. Most importantly, we find that though in bulk lithium nitride, the Li-rich phase, that is, Li3N, is the stable stoichiometry; in small Li(x)N(y) clusters, N-rich phases are more stable at thermodynamic equilibrium.

Early stress evokes dysregulation of histone modifiers in the medial prefrontal cortex across the life span.

Early stress has been hypothesized to recruit epigenetic mechanisms to mediate persistent molecular, cellular, and behavioral changes. Here, we have examined the consequence of the early life stress of maternal separation (ES) on the gene expression of several histone modifiers that regulate histone acetylation and methylation within the medial prefrontal cortex (mPFC), a key limbic brain region that regulates stress responses and mood-related behavior. ES animals exhibit gene regulation of both writer (histone acetyltransferases and histone methyltransferases) and eraser (histone deacetylases and histone lysine demethylases) classes of histone modifiers.

A first-principles study of the III-IV-V semiconductor nanosheets.

Alloying the III-V and IV-IV sheets leads to III-IV-V nano-composites, such as the BC2N sheet, having a lower band gap than their parent III-V counterparts while having higher cohesive energies. Unlike the well known BC2N sheet, the formation energy of the III-IV-V sheets with high Z atomic constituents is much low suggesting in favour of their experimental realisation. From first-principles hybrid density functional calculations, we report a family of group III-IV-V nano-sheets that have their electronic band gap lying between 0.

Early stress evokes temporally distinct consequences on the hippocampal transcriptome, anxiety and cognitive behaviour.

The early stress of maternal separation (ES) exerts long-lasting effects on cognition and anxiety. Recent evidence indicates enhanced hippocampus-dependent spatial learning in young adult ES animals, which shifts towards a decline in long-term memory in middle-aged life. Further, we find that ES animals exhibit enhanced anxiety in young adulthood that does not persist into middle-aged life.