Stone Age genomes shed light on the early evolution, diversity, and ecology of plague.

The bacterial pathogen Yersinia pestis gave rise to devastating outbreaks throughout human history, and ancient DNA evidence has shown it afflicted human populations as far back as the Neolithic. Y. pestis genomes recovered from the Eurasian Late Neolithic/Early Bronze Age (LNBA) period have uncovered key evolutionary steps that led to its emergence from a Yersinia pseudotuberculosis-like progenitor; however, the number of reconstructed LNBA genomes are too few to explore its diversity during this critical period of development.

DFT-Guided Crystal Structure Redetermination and Lattice Dynamics of the Intermetallic Actinoid Compound UIr.

UIr has been discussed as a rare example of a noncentrosymmetric, ferromagnetic superconductor crystallizing in the acentric PdBi structure type (2, 16). Here we present a new structure model for UIr. By means of single-crystal and powder X-ray diffraction we find UIr to crystallize in the symmetric space group 2/, in line with previous calculations.

Layer-dependent topological phase in a two-dimensional quasicrystal and approximant.

The electronic and topological properties of materials are derived from the interplay between crystalline symmetry and dimensionality. Simultaneously introducing "forbidden" symmetries via quasiperiodic ordering with low dimensionality into a material system promises the emergence of new physical phenomena. Here, we isolate a two-dimensional (2D) chalcogenide quasicrystal and approximant, and investigate their electronic and topological properties.

Crystal Structures of α- and β-Nitrogen Trifluoride.

The crystal structures of α-NF and β-NF are reported for the first time. As shown by powder neutron diffraction, the low-temperature α-NF crystallizes in the orthorhombic space group Pnma ( oP16) with lattice parameters a = 6.71457(13) Å, b = 7.

Synthesis and crystal structures of novel tertiary butyl substituted (pseudo-)halogen bismuthanes.

Herein we present the synthesis and characterization of di-tertiary butyl substituted (pseudo-)halogen bismuthanes tBu2BiX (X = Cl (1), Br (2), I (3), CN (4), N3 (5), SCN (6)). These compounds were obtained via different reaction paths. Compound 1 was obtained by a Grignard reaction of BiCl3 with two equivalents of tBuMgCl, whereas compounds 2, 3, 4 and 6 were synthesised by a oxidative addition/reductive elimination pathway starting from tBu3Bi and X2 (X = Br, I, CN, SCN).

A Revised Structure Model for the UCl Structure Type, Novel Modifications of UCl and UBr , and a Comment on the Modifications of Protactinium Pentabromides.

The redetermination of the crystal structure of trigonal UCl , which is the eponym for the UCl structure type, showed that certain atomic coordinates had been incorrectly reported. This led to noticeably different U-Cl distances within the octahedral UCl molecule (2.41 and 2.

The Crystal Structures of α- and β-F Revisited.

The crystal structures of α-F and β-F have been reinvestigated using neutron powder diffraction. For the low-temperature phase α-F , which is stable below circa 45.6 K, the monoclinic space group C2/c with lattice parameters a=5.

Quasicrystal nucleation and module twin growth in an intermetallic glass-forming system.

While quasicrystals possess long-range orientational order they lack translation periodicity. Considerable advancements in the elucidation of their structures and formative principles contrast with comparatively uncharted interrelations, as studies bridging the spatial scales from atoms to the macroscale are scarce. Here, we report on the homogeneous nucleation of a single quasicrystalline seed from the undercooled melt of glass-forming NiZr and its continuous growth into a tenfold twinned dendritic microstructure.

Forcing substitution of tantalum by copper in 1T-TaS: synthesis, structure and electronic properties of 1T-Cu Ta S.

We investigated the compound 1T-Cu Ta S with respect to its synthesis, homogeneity range, structure and electronic properties. The average structure of 1T-Cu Ta S resembles that of the high-temperature phase of the layered transition metal dichalcogenide 1T-TaS in which tantalum is partially substituted by copper. 1T-Cu Ta S readily decomposes at elevated temperatures and can only be prepared and stabilized by a sufficiently high amount of sulfur excess.

The Interhalogen Cations [Br F ] and [Br F ].

The synthesis and characterization of unique polyhalogen cations containing μ-bridging fluorine atoms are reported. The [Br F ] cation features a symmetric [F Br-μ-F-BrF ] bridge, whereas the [Br F ] contains asymmetric μ-F bridges. These fluoronium ions, obtained as [SbF ] salts, were investigated using Raman and F NMR spectroscopy, as well as single-crystal X-ray diffraction.

The [U F ] Anion of Sr[U F ].

The D -symmetric dinuclear complex anion [U F ] of pastel green Sr[U F ] shows a hitherto unknown structural feature: The coordination polyhedra around the U atoms are edge-linked monocapped trigonal prisms, the U atoms are therefore seven-coordinated. This leads to a U-U distance of 3.8913(6) Å.

Redetermination of the crystal structure of KHg(SCN).

Single crystals of KHg(SCN) [dipotassium tetra-thio-cyanato-mercurate(II)] were grown from aqueous solutions of potassium thio-cyanate and mercury(II) thio-cyanate and studied by single-crystal X-ray diffraction. In comparison with the previously reported structure model [Zvonkova (1952 ▸). .

Self-assembly of partially fluorinated hexabenzocoronene derivatives in the solid state.

We report on the synthesis and structural characterization of novel, partially fluorinated hexabenzocoronene (HBC) derivatives. The fluorination of polycyclic aromatic hydrocarbons (PAHs) is a well-established method to enhance the stability of organic semiconductors (OSCs) and render them n-type. For HBC it has been observed that fluorination leads to a modification of the molecular packing motif from a herringbone arrangement to a parallel-packed motif.

Redetermination of the crystal structure of NbF4.

Single crystals of NbF4, niobium(IV) tetra-fluoride, were synthesized by disproportionation of Nb2F5 at 1273 K in a sealed niobium tube, extracted and studied by single-crystal X-ray diffraction. Previous reports on the crystal structure of NbF4 were based on X-ray powder diffraction data and the observed isotypicity to SnF4 [Gortsema & Didchenko (1965 ▸). Inorg.

Modeling the hypothalamus-pituitary-adrenal system: homeostasis by interacting positive and negative feedback.

The hypothalamus-pituitary-adrenal (HPA) system is closely related to stress and the restoration of homeostasis. This system is stimulated in the second half of the night, decreases its activity in the daytime, and reaches the homeostatic level during the late evening. In this paper, we derive and discuss a novel model for the HPA system.

Large, larger, largest--a family of cluster-based tantalum copper aluminides with giant unit cells. II. The cluster structure.

This is the second of two papers, where we discuss the cluster structures of a novel family of cluster-based intermetallic phases of unprecedented complexity: cF444-Al(63.6)Ta(36.4) (AT-19), a = 19.

Large, larger, largest--a family of cluster-based tantalum copper aluminides with giant unit cells. I. Structure solution and refinement.

This is the first of two parts, where we report the structure determination of a novel family of cluster-based intermetallic phases of unprecedented complexity: cF444-Al(63.6)Ta(36.4) (AT-19), a = 19.

Pd(0.213)Cd(0.787) and Pd(0.235)Cd(0.765) structures: their long c axis and composite crystals, chemical twinning, and atomic site preferences.

We present single-crystal studies of Pd(0.213)Cd(0.787) and Pd(0.

Ta97Te60: a crystalline approximant of a tantalum telluride quasicrystal with twelvefold rotational symmetry.

The crystal structure of a rational approximant of an unprecedented dodecagonal quasicrystal is reported. The atomic arrangement of the tantalum-rich telluride Ta(97)Te(60) has been determined from 30 458 symmetrically independent X-ray intensities of a crystal twinned by metric merohedry: a=2767.2(2), b=2767.

Type I keratin cDNAs from the rainbow trout: independent radiation of keratins in fish.

Five different type I keratins from a teleost fish, the rainbow trout Oncorhynchus mykiss, have been sequenced by cDNA cloning and identified at the protein level by peptide mass mapping using MALDI-MS. This showed that the entire range of type I keratins detected biochemically in this fish has now been sequenced. Three of the keratins are expressed in the epidermis (subtype Ie), whereas the other two occur in simple epithelia and mesenchymal cells (subtype Is).

A Dodecagonal Quasicrystalline Chalcogenide.

Diffractograms with twelvefold rotational symmetry (depicted on the right) were obtained from the first quasicrystalline chalcogenide Ta Te. This compound was prepared on a preparative scale by the reduction of TaTe with tantalum below 1870 K. This tantalum-rich telluride, which is the first stable dodecagonal phase, has enabled an in-depth investigation of this unusual state of ordering.