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Due to the rapidly developing technologies and huge market demand, there has been increasing interest internationally in exploring permanent magnet formulations in addition to the well-known Nd2Fe14B and SmCo5/Sm2Co17. Given Fe's low materials cost and generally high magnetization, Fe-rich rare earth binaries such as Ce2Fe17 comprise a rich "hunting ground" for such new materials. While this compound suffers from a low ordering point and is a helimagnet, these difficulties are easily remedied by the substitution of appropriate amounts of cobalt for Fe, with room-temperature saturation magnetization as high as 1.5 T. Here, we try to switch the all-important magnetic anisotropy from planar to uniaxial behavior in Ce2Fe17 via 18h- and 6c-type atom substitutions with Si, Ir, and numerous other atoms. The uniaxial magnetocrystalline anisotropy is successfully achieved in the 6c-site-substituted Ce2Fe15Ir2 systems, along with large magnetization. We find that iridium substitution, in particular, induces a substantial uniaxial anisotropy of 11.25 MJ/m3, which is comparable to most of the current rare earth permanent magnets. Although the iridium substitution is costly, the finding of Ir-triggered uniaxial magnetic anisotropy indicates the potential of Ce–Fe-based alloys for permanent magnets. [ABSTRACT FROM AUTHOR]

Crystallographic and magnetic properties of Fe5PB2, Fe4CoPB2, Fe4MnPB2, Fe5SiB2, Fe4CoSiB2, and Fe4MnSiB2 are reported. All adopt the tetragonal Cr5B3 structure-type and are ferromagnetic at room temperature with easy axis of magnetization along the c-axis. The spin reorientation in Fe5SiB2 is observed as an anomaly in the magnetization near 170K and is suppressed by substitution of Co or Mn for Fe. The silicides are found to generally have larger magnetic moments than the phosphides, but the data suggest smaller magnetic anisotropy in the silicides. Cobalt substitution reduces the Curie temperatures by more than 100K and ordered magnetic moments by 16%-20%, while manganese substitution has a much smaller effect. This suggests Mn moments align ferromagnetically with the Fe and that Co does not have an ordered moment in these structures. Anisotropic thermal expansion is observed in Fe5PB2 and Fe5SiB2, with negative thermal expansion seen along the c-axis of Fe5SiB2. First principles calculations of the magnetic properties of Fe5SiB2 and Fe4MnSiB2 are reported. The results, including the magnetic moment and anisotropy, are in good agreement with experiment. [ABSTRACT FROM AUTHOR]

Solids with ultralow thermal conductivity are of great interest as thermal barrier coatings for insulation or thermoelectrics for energy conversion. However, the theoretical limits of lattice thermal conductivity ( k ) are unclear. In typical crystals a phonon picture is valid, whereas lowest k values occur in highly disordered materials where this picture fails and heat is supposedly carried by random walk among uncorrelated oscillators. Here we identify a simple crystal, Tl 3 VSe 4 , with a calculated phonon k [0.16 Watts per meter-Kelvin (W/m-K)] one-half that of our measured k (0.30 W/m-K) at 300 K, approaching disorder k values, although Raman spectra, specific heat, and temperature dependence of k reveal typical phonon characteristics. Adding a transport component based on uncorrelated oscillators explains the measured k and suggests that a two-channel model is necessary for crystals with ultralow k . [ABSTRACT FROM AUTHOR]

Layered thallium copper chalcogenides can form single, double, or triple layers of Cu– Ch separated by Tl sheets. Here we report on the preparation and properties of Tl-based materials of TlCu 2 Se 2 , TlCu 4 S 3 , TlCu 4 Se 3 and TlCu 6 S 4 . Having no long-range magnetism for these materials is quite surprising considering the possibilities of inter- and intra-layer exchange interactions through Cu 3 d , and we measure by magnetic susceptibility and confirm by neutron diffraction. First principles density-functional theory calculations for both the single-layer TlCu 2 Se 2 (isostructural to the ‘122’ iron-based superconductors) and the double-layer TlCu 4 Se 3 suggest a lack of Fermi-level spectral weight that is needed to drive a magnetic or superconducting instability. However, for multiple structural layers with Fe, there is much greater likelihood for magnetism and superconductivity. [ABSTRACT FROM AUTHOR]

We present magnetization isotherms in pulsed magnetic fields up to 62 T, supported by first-principles calculations, demonstrating a huge uniaxial magnetocrystalline anisotropy energy-approximately 20 MJ/m3-in UMn2Ge2. This large anisotropy results from the extremely strong spin-orbit coupling affecting the uranium 5f electrons, which in the calculations exhibit a substantial orbital moment exceeding 2μB. We also find from theoretical calculations that a number of isostructural Mn actinide compounds are expected to have similarly large anisotropy. [ABSTRACT FROM AUTHOR]

The article offers the author's insights on the impact of the middle class on world markets, entrepreneurial innovation, and democracy. Topics discussed include the economic theory Purchasing Power Parity (PPP), the definition of middle class as an identity to deny socioeconomic stratification's reality, and the definition of Dennis Gilbert, a sociologist, of the Mexican middle class.

Fuchs corneal dystrophy (FCD) is a genetic disorder of the corneal endothelium and is the most common cause of corneal transplantation in the United States. Previously, we mapped a late-onset FCD locus, FCD2, on chromosome 18q. Here, we present next-generation sequencing of all coding exons in the FCD2 critical interval in a multigenerational pedigree in which FCD segregates as an autosomal-dominant trait. We identified a missense change in LOXHD1, a gene causing progressive hearing loss in humans, as the sole variant capable of explaining the phenotype in this pedigree. We observed LOXHD1 mRNA in cultured human corneal endothelial cells, whereas antibody staining of both human and mouse corneas showed staining in the corneal epithelium and endothelium. Corneal sections of the original proband were stained for LOXHD1 and demonstrated a distinct increase in antibody punctate staining in the endothelium and Descemet membrane; punctate staining was absent from both normal corneas and FCD corneas negative for causal LOXHD1 mutations. Subsequent interrogation of a cohort of >200 sporadic affected individuals identified another 15 heterozygous missense mutations that were absent from >800 control chromosomes. Furthermore, in silico analyses predicted that these mutations reside on the surface of the protein and are likely to affect the protein''s interface and protein-protein interactions. Finally, expression of the familial LOXHD1 mutant allele as well as two sporadic mutations in cells revealed prominent cytoplasmic aggregates reminiscent of the corneal phenotype. All together, our data implicate rare alleles in LOXHD1 in the pathogenesis of FCD and highlight how different mutations in the same locus can potentially produce diverse phenotypes. [Copyright &y& Elsevier]

Scholars have generally argued that the modern triumph of a language of class eclipsed collective identities rooted in older, more hierarchical conceptions of rank and estate. This article, drawing on the author's previously published research on white-collar workers in twentieth-century Peru, comes to a radically different conclusion. Despite using what appeared to be an explicit and often combative discourse of class interest and class conflict, Peru's white-collar workers justified their demands by emphasizing the difference between themselves and manual workers. Masquerading as class consciousness were many of the rhetorical tropes that had long legitimated the society of orders, including a presumption that social standing was an innate quality fixed at birth. Corporatist social legislation adopted in the 1920s reinforced the principle that white-collar and blue-collar workers were distinct species of human beings deserving of entirely different benefits. Unequal rights became enshrined in labor law. [ABSTRACT FROM AUTHOR]

Looks at the 1919 January general strike and its consideration as being Peru's founding labour movement. Decree issued by Peru's president, Jose Pardo y Barreda; President Pardo negotiated with workers; Reasons for his choice.

Using first principles calculations, we studied the effect of Si substitution in the hexagonal Fe3Ge. We find the low temperature magnetic anisotropy in this system to be planar and originating mostly from the spin-orbit coupling in Fe-d states. Reduction of the unitcell volume reduces the magnitude of in-plane magnetic anisotropy, eventually turning it positive which reorients the magnetic moments to the axial direction. Substituting Ge with the smaller Si ions also increases the anisotropy, potentially enhancing the region of stability of the axial magnetization, which is beneficial for magnetic applications such as permanent magnets. Our experimental measurements on samples of Fe3Ge1–xSix confirm these predictions and show that substitution of about 6% of the Ge with Si increases by approximately 35K the temperature range over which anisotropy is uniaxial. [ABSTRACT FROM AUTHOR]

We present a combined theoretical and experimental study of alloys of the high performance piezoelectric PZT (PbZr0.5Ti0.5O3) with BZnT (BiZn0.5Ti0.5O3) and BZnZr (BiZn0.5Zr0.5O3), focusing on atomic displacements, ferroelectric polarization, and elastic stability. From theory we find that the 75-25 PZT-BZnT alloy has substantially larger cation displacements, and hence ferroelectric polarization than the PZT base material, on the tetragonal side of the phase diagram. We also find a possible morphotrophic phase boundary in this system by comparing displacement patterns and optimized c/a ratios. Elastic stability calculations find the structures to be essentially stable. Experiments indicate the feasibility of sample synthesis within this alloy system, although measurements do not find significant polarization, probably due to a large coercive field. [ABSTRACT FROM AUTHOR]

Superconductivity is observed with critical temperatures near 9 K in the tetragonal compound Mo5PB2. This material adopts the Cr5B3 structure type common to superconducting Nb5Si3-xBx,Mo5SiB2, and W5SiB2, which have critical temperatures of 5.8-7.8 K. We have synthesized polycrystalline samples of the compound, made measurements of electrical resistivity, magnetic susceptibility, and heat capacity, and performed first-principles electronic structure calculations. The highest Tc value (9.2 K) occurs in slightly phosphorus rich samples, with composition near Mo5P1.1B1.9, and the upper critical field Hc2 at T=0 is estimated to be ≈17 kOe. Together, the measurements and band-structure calculations indicate intermediate coupling (λ=1.0), phonon mediated superconductivity. The temperature dependence of the heat capacity and upper critical field Hc2 below Tc suggest multiple superconducting gaps may be present. [ABSTRACT FROM AUTHOR]

How signaling cascades influence gene regulation at the level of chromatin modification is not well understood. We studied this process using the Wingless/Wnt pathway in Drosophila. When cells sense Wingless ligand, Armadillo (the fly ß-catenin) becomes stabilized and translocates to the nucleus, where it binds to the sequence-specific DNA binding protein TCF to activate transcription of target genes. Here, we show that Wingless signaling induces TCF and Armadillo recruitment to a select subset of TCF binding site clusters that act as Wingless response elements. Despite this localized TCF/Armadillo recruitment, histones are acetylated over a wide region (up to 30 kb) surrounding the Wingless response elements in response to pathway activation. This widespread histone acetylation occurs independently of transcription. In contrast to Wingless targets, other active genes not regulated by the pathway display sharp acetylation peaks centered on their core promoters. Widespread acetylation of Wingless targets is dependent upon CBP, a histone acetyltransferase known to bind to Armadillo and is correlated with activation of target gene expression. These data suggest that pathway activation induces localized recruitment of TCF/Armadillo/CBP to Wingless response elements, leading to widespread histone acetylation of target loci prior to transcriptional activation. [ABSTRACT FROM AUTHOR]

Background: There is increasing evidence that tissue-specific modifications of basic cellular functions play an important role in development and disease. To identify the functions of COPI coatomer-mediated membrane trafficking in Drosophila development, we were aiming to create loss-of-function mutations in the γCOP gene, which encodes a subunit of the COPI coatomer complex. Principal Findings: We found that γCOP is essential for the viability of the Drosophila embryo. In the absence of zygotic γCOP activity, embryos die late in embryogenesis and display pronounced defects in morphogenesis of the embryonic epidermis and of tracheal tubes. The coordinated cell rearrangements and cell shape changes during tracheal tube morphogenesis critically depend on apical secretion of certain proteins. Investigation of tracheal morphogenesis in γCOP loss-of-function mutants revealed that several key proteins required for tracheal morphogenesis are not properly secreted into the apical lumen. As a consequence, γCOP mutants show defects in cell rearrangements during branch elongation, in tube dilation, as well as in tube fusion. We present genetic evidence that a specific subset of the tracheal defects in γCOP mutants is due to the reduced secretion of the Zona Pellucida protein Piopio. Thus, we identified a critical target protein of COPI-dependent secretion in epithelial tube morphogenesis. Conclusions/Significance: These studies highlight the role of COPI coatomer-mediated vesicle trafficking in both general and tissue-specific secretion in a multicellular organism. Although COPI coatomer is generally required for protein secretion, we show that the phenotypic effect of γCOP mutations is surprisingly specific. Importantly, we attribute a distinct aspect of the γCOP phenotype to the effect on a specific key target protein. [ABSTRACT FROM AUTHOR]

Many Wnts influence cell behavior by a conserved signaling cascade that promotes the stabilization and nuclear accumulation of β-catenin (β-cat), which then associates with TCF family members to activate target genes. The histone acetyltransferase CREB binding protein (CBP) can bind to TCF and inhibit Wnt signaling in Drosophila. In contrast, studies in vertebrates indicate a positive role for CBP and the closely related protein p300 as β-cat binding transcriptional co-activators. We address this discrepancy by demonstrating that in addition to its negative role, CBP has an essential positive role in Wnt signaling in flies. CBP binds directly to the C-terminus of Armadillo (Arm, the fly β-cat) and is recruited to a Wnt-regulated enhancer (WRE) in a Wnt- and Arm-dependent manner. In a human colorectal cancer cell line, we show that CBP and p300 can inhibit Wnt signaling and demonstrate that human p300 can bind directly to TCF4 in vitro. Our results argue that CBP/p300 has an evolutionarily conserved role as a buffer regulating TCF-β-cat/Arm binding. Subsequent to this interaction, it also has an essential role in mediating the transactivation activity of β-cat/Arm. [ABSTRACT FROM AUTHOR]

This study investigates magnetic ordering temperature in nano- and mesoscale structural features in an iron arsenide. Although magnetic ground states in quantum materials can be theoretically predicted from known crystal structures and chemical compositions, the ordering temperature is harder to pinpoint due to potential local lattice variations that calculations may not account for. In this work we find surprisingly that a locally disordered material can exhibit a significantly larger Néel temperature (TN) than an ordered material of precisely the same chemical stoichiometry. Here, a EuFe2As2 crystal, which is a '122' parent of iron arsenide superconductors, is found through synthesis to have ordering below TN = 195 K (for the locally disordered crystal) or TN = 175 K (for the ordered crystal). In the higher TN crystals, there are shorter planar Fe-Fe bonds [2.7692(2) Å vs. 2.7745(3) Å], a randomized in-plane defect structure, and diffuse scattering along the [00 L] crystallographic direction that manifests as a rather broad specific heat peak. For the lower TN crystals, the a-lattice parameter is larger and the in-plane microscopic structure shows defect ordering along the antiphase boundaries, giving a larger TN and a higher superconducting temperature (Tc) upon the application of pressure. First-principles calculations find a strong interaction between c-axis strain and interlayer magnetic coupling, but little impact of planar strain on the magnetic order. Neutron single-crystal diffraction shows that the low-temperature magnetic phase transition due to localized Eu moments is not lattice or disorder sensitive, unlike the higher-temperature Fe sublattice ordering. This study demonstrates a higher magnetic ordering point arising from local disorder in 122. [ABSTRACT FROM AUTHOR]

We investigate the thermodynamic and transport properties of silver-substituted BaFe2As2 (122) crystals up to ~4.5%. Similar to other transition-metal substitutions in 122, Ag diminishes the antiferromagnetic (TN) and structural (TS) transition temperatures, but unlike other electron-doped 122s, TN and TS coincide without splitting. Although magnetism drops precipitously to TN = 84K at doping x = 0.029, it only weakly changes above this x, settling at TN = 80K at x = 0.045. Compared to this persistent magnetism in Ag-122, doping other group 11 elements of either Cu or Au in 122 diminished TN and induced superconductivity near Tc = 2K at x = 0.044 or 0.031, respectively. Ag-122 crystals show reflective surfaces with surprising thicker cross sections for x=0.019, the appearance that is in contrast to the typical thin stacked layered feature seen in all other flux-grown x122 and lower Ag-122. This physical trait may be a manifest of intrinsic weak changes in c lattice and TN. Our theoretical calculations suggest that Ag doping produces strong electronic scattering and yet a relatively small disruption of the magnetic state, both of which preclude superconductivity in this system. [ABSTRACT FROM AUTHOR]

Single crystals of ( Nd 1 − x Ce x ) 2 Fe 14 B , some reaching ∼ 6 × 8 × 8 mm 3 in volume, are grown out of Fe-(Nd, Ce) flux. This crystal growth method allows for large ( Nd 1 − x Ce x ) 2 Fe 14 B single crystals to be synthesized using a simple flux growth procedure. Chemical and structural analyses of the crystals indicate that ( Nd 1 − x Ce x ) 2 Fe 14 B forms a solid solution until at least x =0.38 with a Vegard-like variation of the lattice constants with x . Refinements of single crystal neutron diffraction data indicate that Ce has a slight site preference (7:3) for the 4 g rare earth site over the 4 f site. Magnetization measurements at 300 K show only small decreases with increasing Ce content in saturation magnetization ( M s ) and anisotropy field ( H A ), and Curie temperature ( T C ). First principles calculations are carried out to understand the effect of Ce substitution on the electronic and magnetic properties. For a multitude of applications, it is expected that the advantage of incorporating lower-cost and more abundant Ce will outweigh the small adverse effects on magnetic properties. Ce-substituted Nd 2 Fe 14 B is therefore a potential high-performance permanent magnet material with substantially reduced Nd content. [ABSTRACT FROM AUTHOR]

ZrMnP and HfMnP single crystals are grown by a self-flux growth technique, and structural as well as temperature dependent magnetic and transport properties are studied. Both compounds have an orthorhombic crystal structure. ZrMnP and HfMnP are ferromagnetic with Curie temperatures around 370K and 320 K, respectively. The spontaneous magnetizations of ZrMnP and HfMnP are determined to be 1.9 μB/f.u. and 2.1 μB/f.u., respectively, at 50K. The magnetocaloric effect of ZrMnP in terms of entropy change (ΔS) is estimated to be -6.7 kJ m-3 K-1 around 369K. The easy axis of magnetization is [100] for both compounds, with a small anisotropy relative to the [010] axis. At 50 K, the anisotropy field along the [001] axis is ~4.6 T for ZrMnP and ~10T for HfMnP. Such large magnetic anisotropy is remarkable considering the absence of rare-earth elements in these compounds. The first principle calculation correctly predicts the magnetization and hard axis orientation for both compounds, and predicts the experimental HfMnP anisotropy field within 25%. More importantly, our calculations suggest that the large magnetic anisotropy comes primarily from the Mn atoms, suggesting that similarly large anisotropies may be found in other 3d transition metal compounds. [ABSTRACT FROM AUTHOR]

The Hedgehog signaling pathway is part of the ancient developmental-evolutionary animal toolkit. Frequently co-opted to pattern new structures, the pathway is conserved among eumetazoans yet flexible and pleiotropic in its effects. The Hedgehog receptor, Patched, is transcriptionally activated by Hedgehog, providing essential negative feedback in all tissues. Our locus-wide dissections of the cis-regulatory landscapes of fly patched and mouse Ptch1 reveal abundant, diverse enhancers with stage- and tissue-specific expression patterns. The seemingly simple, constitutive Hedgehog response of patched/Ptch1 is driven by a complex regulatory architecture, with batteries of context-specific enhancers engaged in promoter-specific interactions to tune signaling individually in each tissue, without disturbing patterning elsewhere. This structure--one of the oldest cis-regulatory features discovered in animal genomes--explains how patched/Ptch1 can drive dramatic adaptations in animal morphology while maintaining its essential core function. It may also suggest a general model for the evolutionary flexibility of conserved regulators and pathways. [ABSTRACT FROM AUTHOR]

Single crystals of Fe 5 B 2 P were grown by self-flux growth technique. Structural and electrical and magnetic anisotropic properties are studied. The Curie temperature of Fe 5 B 2 P is determined to be 655±2 K. The saturation magnetization is determined to be 1.72 μ B / Fe at 2 K. The temperature variation of the anisotropy constant K 1 is determined for the first time, reaching ∼ 0.50 MJ / m 3 at 2 K, and it is comparable to that of hard ferrites. The saturation magnetization is found to be larger than the hard ferrites. The first principle calculations of saturation magnetization and anisotropy constant are found to be consistent with the experimental results. [ABSTRACT FROM AUTHOR]

The Hedgehog (Hh) signaling pathway directs a multitude of cellular responses during embryogenesis and adult tissue homeostasis. Stimulation of the pathway results in activation of Hh target genes by the transcription factor Ci/Gli, which binds to specific motifs in genomic enhancers. In Drosophila, only a few enhancers (patched, decapentaplegic, wingless, stripe, knot, hairy, orthodenticle) have been shown by in vivo functional assays to depend on direct Ci/Gli regulation. All but one (orthodenticle) contain more than one Ci/Gli site, prompting us to directly test whether homotypic clustering of Ci/Gli binding sites is sufficient to define a Hh-regulated enhancer. We therefore developed a computational algorithm to identify Ci/Gli clusters that are enriched over random expectation, within a given region of the genome. Candidate genomic regions containing Ci/Gli clusters were functionally tested in chicken neural tube electroporation assays and in transgenic flies. Of the 22 Ci/Gli clusters tested, seven novel enhancers (and the previously known patched enhancer) were identified as Hh-responsive and Ci/Gli-dependent in one or both of these assays, including: Cuticular protein 100A (Cpr100A); invected (inv), which encodes an engrailed-related transcription factor expressed at the anterior/posterior wing disc boundary; roadkill (rdx), the fly homolog of vertebrate Spop; the segment polarity gene gooseberry (gsb); and two previously untested regions of the Hh receptor-encoding patched (ptc) gene. We conclude that homotypic Ci/Gli clustering is not sufficient information to ensure Hh-responsiveness; however, it can provide a clue for enhancer recognition within putative Hedgehog target gene loci. [ABSTRACT FROM AUTHOR]

Understanding the role of spin-orbit coupling (SOC) has been crucial for controlling magnetic anisotropy in magnetic multilayer films. It has been shown that electronic structure can be altered via interface SOC by varying the superlattice structure, resulting in spontaneous magnetization perpendicular or parallel to the plane. In lieu of magnetic thin films, we study the similarly anisotropic helimagnet Cr1/3NbS2 where the spin-polarization direction, controlled by the applied magnetic field, can modify the electronic structure. As a result, the direction of spin polarization can modulate the density of states and in turn affect the in-plane electrical conductivity. In Cr1/3NbS2, we found an enhancement of in-plane conductivity when the spin polarization is out-of-plane as compared to in-plane spin polarization. This is consistent with the increase in density of states near the Fermi energy at the same spin configuration, found from first-principles calculations. We also observe unusual field dependence of the Hall signal in the same temperature range. This is unlikely to originate from the noncollinear spin texture but rather further indicates strong dependence of electronic structure on spin orientation relative to the plane. [ABSTRACT FROM AUTHOR]

Hexagonal Fe3Sn has many of the desirable properties for a new permanent magnet phase with a Curie temperature of 725 K, a saturation moment of 1.18 MA/m. and anisotropy energy, K1 of 1.8 MJ/m3. However, contrary to earlier experimental reports, we found both experimentally and theoretically that the easy magnetic axis lies in the hexagonal plane, which is undesirable for a permanent magnet material. One possibility for changing the easy axis direction is through alloying. We used first principles calculations to investigate the effect of elemental substitutions. The calculations showed that substitution on the Sn site has the potential to switch the easy axis direction. However, transition metal substitutions with Co or Mn do not have this effect. We attempted synthesis of a number of these alloys and found results in accord with the theoretical predictions for those that were formed. However, the alloys that could be readily made all showed an in-plane easy axis. The electronic structure of Fe3Sn is reported, as are some are magnetic and structural properties for the Fe3Sn2, and Fe5Sn3 compounds, which could be prepared as mm-sized single crystals. [ABSTRACT FROM AUTHOR]

Cilia are critical mediators of paracrine signaling; however, it is unknown whether proteins that contribute to ciliopathies converge on multiple paracrine pathways through a common mechanism. Here, we show that loss of cilopathy-associated proteins Bardet-Biedl syndrome 4 (BBS4) or oral-facial-digital syndrome 1 (OFD1) results in the accumulation of signaling mediators normally targeted for proteasomal degradation. In WT cells, several BBS proteins and OFD1 interacted with proteasomal subunits, and loss of either BBS4 or OFD1 led to depletion of multiple subunits from the centrosomal proteasome. Furthermore, overexpression of proteasomal regulatory components or treatment with proteasomal activators sulforaphane (SFN) and mevalonolactone (MVA) ameliorated signaling defects in cells lacking BBS1, BBS4, and OFD1, in morphant zebrafish embryos, and in induced neurons from Ofd1-deficient mice. Finally, we tested the hypothesis that other proteasome-dependent pathways not known to be associated with ciliopathies are defective in the absence of ciliopathy proteins. We found that loss of BBS1, BBS4, or OFD1 led to decreased NF-κB activity and concomitant IκBβ accumulation and that these defects were ameliorated with SFN treatment. Taken together, our data indicate that basal body proteasomal regulation governs paracrine signaling pathways and suggest that augmenting proteasomal function might benefit ciliopathy patients. [ABSTRACT FROM AUTHOR]

Cilia are critical mediators of paracrine signaling; however, it is unknown whether proteins that contribute to ciliopathies converge on multiple paracrine pathways through a common mechanism. Here, we show that loss of cilopathy-associated proteins Bardet-Biedl syndrome 4 (BBS4) or oral-facial-digital syndrome 1 (OFD1) results in the accumulation of signaling mediators normally targeted for proteasomal degradation. In WT cells, several BBS proteins and OFD1 interacted with proteasomal subunits, and loss of either BBS4 or OFD1 led to depletion of multiple subunits from the centrosomal proteasome. Furthermore, overexpression of proteasomal regulatory components or treatment with proteasomal activators sulforaphane (SFN) and mevalonolactone (MVA) ameliorated signaling defects in cells lacking BBS1, BBS4, and OFD1, in morphant zebrafish embryos, and in induced neurons from Ofd1-deficient mice. Finally, we tested the hypothesis that other proteasome-dependent pathways not known to be associated with ciliopathies are defective in the absence of ciliopathy proteins. We found that loss of BBS1, BBS4, or OFD1 led to decreased NF-κB activity and concomitant IμBβ accumulation and that these defects were ameliorated with SFN treatment. Taken together, our data indicate that basal body proteasomal regulation governs paracrine signaling pathways and suggest that augmenting proteasomal function might benefit ciliopathy patients. [ABSTRACT FROM AUTHOR]

Antimony telluride has a low thermoelectric figure of merit (ZT < ∼0.3) because of a low Seebeck coefficient α arising from high degenerate hole concentrations generated by antimony antisite defects. Here, we mitigate this key problem by suppressing antisite defect formation using subatomic percent sulfur doping. The resultant 10–25% higher α in bulk nanocrystalline antimony telluride leads to ZT ∼ 0.95 at 423 K, which is superior to the best non-nanostructured antimony telluride alloys. Density functional theory calculations indicate that sulfur increases the antisite formation activation energy and presage further improvements leading to ZT ∼ 2 through optimized doping. Our findings are promising for designing novel thermoelectric materials for refrigeration, waste heat recovery, and solar thermal applications. [ABSTRACT FROM AUTHOR]

The relationship between vacancy ordering and magnetism in TlFe1.6Se2 has been investigated via single crystal neutron diffraction, nuclear forward scattering, and transmission electron microscopy. The examination of chemically and structurally homogeneous crystals allows the true ground state to be revealed, which is characterized by Fe moments lying in the ab plane below 100 K. This is in sharp contrast to crystals containing regions of order and disorder, where a competition between c axis and ab plane orientations of the moments is observed. The properties of partially disordered TlFe1.6Se2 are, therefore, not associated with solely the ordered or disordered regions. This contrasts the viewpoint that phase separation results in independent physical properties in intercalated iron selenides, suggesting a coupling between ordered and disordered regions may play an important role in the superconducting analogues. [ABSTRACT FROM AUTHOR]

We present a comprehensive neutron scattering study of the breathing pyrochlore magnet LiGaCr4S8. We observe an unconventional magnetic excitation spectrum with a separation of high- and low-energy spin dynamics in the correlated paramagnetic regime above a spin-freezing transition at 12(2) K. By fitting to magnetic diffuse-scattering data, we parametrize the spin Hamiltonian. We find that interactions are ferromagnetic within the large and small tetrahedra of the breathing pyrochlore lattice, but antiferromagnetic further-neighbor interactions are also essential to explain our data, in qualitative agreement with density-functional-theory predictions [Ghosh et al., npj Quantum Mater. 4, 63 (2019)]. We explain the origin of geometrical frustration in LiGaCr4S8 in terms of net antiferromagnetic coupling between emergent tetrahedral spin clusters that occupy a face-centered-cubic lattice. Our results provide insight into the emergence of frustration in the presence of strong further-neighbor couplings, and a blueprint for the determination of magnetic interactions in classical spin liquids. [ABSTRACT FROM AUTHOR]

Thermal conductivities of La3Cu3X4(X=P,As,Sb,Bi) compounds are examined using first-principles density functional theory and Boltzmann transport methods. We observe a trend of increasing lattice thermal conductivity (l) with increasing atomic mass, challenging our expectations, as lighter mass systems typically have larger sound speeds and weaker intrinsic scattering. In particular, we find that La3Cu3P4 has the lowest l, despite having larger sound speed and the most restricted available phase space for phonon-phonon scattering, an important criterion for estimating and comparing l among like systems. The origin of this unusual behavior lies in the strength of the individual anharmonic phonon scattering matrix elements, which are much larger in La3Cu3P4 than in the heavier La3Cu3Bi4 system. Our finding provides insights into the interplay of harmonic and anharmonic properties of complex, low-thermal-conductivity compounds, of potential use for thermoelectric and thermal barrier coating applications. [ABSTRACT FROM AUTHOR]