Crystal Structure of (E)-2-[(2- bromo-3-pyridyl)methylidene]-6-methoxy-3,4-dihydronaphthalen-1-one and 3-[(E)-(6- methoxy-3,4-dihydronaphth-2-oylidene)methyl]-1H-pyridin-2-one

The title compounds C17H14BrNO2, (I), and C17H15NO3, (II), were obtained from the reaction of 6-meth­oxy-3,4-di­hydro-2H-naphthalen-1-one and 2-bromo­nicotinaldehyde in ethanol. Compound (I) was the expected product and compound (II) was the oxidation product from air exposure. In the crystal structure of compound (I), there are no short contacts or hydrogen bonds. The structure does display [pi]-[pi] inter­actions between adjacent benzene rings and adjacent pyridyl rings. Compound (II) contains two independent mol­ecules, A and B, in the asymmetric unit; both are non-planar, the dihedral angles between the meth­oxy­benzene and 1H-pyridin-2-one mean planes being 35.07 (9)° in A and 35.28 (9)°in B. In each mol­ecule, the 1H-pyridin-2-one unit participates in inter­molecular N-H...O hydrogen bonding to another mol­ecule of the same type (A to A or B to B). The structure also displays [pi]-[pi] inter­actions between the pyridyl and the benzene rings of non-equivalent mol­ecules (viz., A to B and B to A)

Superconductors with Magnetic Impurities: Instantons and Sub-gap States

When subject to a weak magnetic impurity potential, the order parameter and quasi-particle energy gap of a bulk singlet superconductor are suppressed. According to the conventional mean-field theory of Abrikosov and Gor'kov, the integrity of the energy gap is maintained up to a critical concentration of magnetic impurities. In this paper, a field theoretic approach is developed to critically analyze the validity of the mean field theory. Using the supersymmetry technique we find a spatially homogeneous saddle-point that reproduces the Abrikosov-Gor'kov theory, and identify instanton contributions to the density of states that render the quasi-particle energy gap soft at any non-zero magnetic impurity concentration. The sub-gap states are associated with supersymmetry broken field configurations of the action. An analysis of fluctuations around these configurations shows how the underlying supersymmetry of the action is restored by zero modes. An estimate of the density of states is given for all dimensionalities. To illustrate the universality of the present scheme we apply the same method to study `gap fluctuations' in a normal quantum dot coupled to a superconducting terminal. Using the same instanton approach, we recover the universal result recently proposed by Vavilov et al. Finally, we emphasize the universality of the present scheme for the description of gap fluctuations in d-dimensional superconducting/normal structures.Comment: 18 pages, 9 eps figure

Broad-line radio galaxies: old and feeble?

Far-infrared photometry of broad-line radio galaxies shows this class of AGN to consist of many hot and some cool infrared emitters, with peaks in their spectral energy distributions around 25 micron or longward of 60 micron, respectively. Quantitative analysis indicates that this distribution relates to a substantial dispersion in the strength of the cool dust component: broad-line radio galaxies are relatively poor in large-scale dust. Possibly they have undergone a different merger evolution, or are relatively old AGN.Comment: Accepted for publication in A&A Letter

Pre-M Phase-promoting Factor Associates with Annulate Lamellae in Xenopus Oocytes and Egg Extracts

We have used complementary biochemical and in vivo approaches to study the compartmentalization of M phase-promoting factor (MPF) in prophase Xenopus eggs and oocytes. We first examined the distribution of MPF (Cdc2/CyclinB2) and membranous organelles in high-speed extracts of Xenopus eggs made during mitotic prophase. These extracts were found to lack mitochondria, Golgi membranes, and most endoplasmic reticulum (ER) but to contain the bulk of the pre-MPF pool. This pre-MPF could be pelleted by further centrifugation along with components necessary to activate it. On activation, Cdc2/CyclinB2 moved into the soluble fraction. Electron microscopy and Western blot analysis showed that the pre-MPF pellet contained a specific ER subdomain comprising "annulate lamellae" (AL): stacked ER membranes highly enriched in nuclear pores. Colocalization of pre-MPF with AL was demonstrated by anti-CyclinB2 immunofluorescence in prophase oocytes, in which AL are positioned close to the vegetal surface. Green fluorescent protein-CyclinB2 expressed in oocytes also localized at AL. These data suggest that inactive MPF associates with nuclear envelope components just before activation. This association may explain why nuclei and centrosomes stimulate MPF activation and provide a mechanism for targeting of MPF to some of its key substrates

Cyclin B1 is essential for mitosis in mouse embryos, and its nuclear export sets the time for mitosis.

There is remarkable redundancy between the Cyclin-Cdk complexes that comprise the cell cycle machinery. None of the mammalian A-, D-, or E-type cyclins are required in development until implantation, and only Cdk1 is essential for early cell divisions. Cyclin B1 is essential for development, but whether it is required for cell division is contentious. Here, we used a novel imaging approach to analyze Cyclin B1-null embryos from fertilization onward. We show that Cyclin B1-/- embryos arrest in G2 phase after just two divisions. This is the earliest arrest of any Cyclin known and places Cyclin B1 with cdk1 as the essential regulators of the cell cycle. We reintroduced mutant proteins into this genetically null background to determine why Cyclin B1 is constantly exported from the nucleus. We found that Cyclin B1 must be exported from the nucleus for the cell to prevent premature entry to mitosis, and retaining Cyclin B1-Cdk1 at the plasma membrane precludes entry to mitosis

Challenges Faced by Persons with Disabilities Using Self-Service Technologies

Foreseeable game changing solutions to SSTs will allow for better universal access by better implementing features that are easy and intuitive to use from the inception. Additional robotic advancements will allow for better and easier delivery of goods for consumers. Improvements to artificial intelligence will allow for better communication through natural language and alternative forms of communication. Furthermore, artificial intelligence will aid consumers at SSTs by remembering the consumers preferences and needs. With all foreseeable game changing solutions people with disabilities will be consulted when new and improved SSTs are being developed allowing for the SST to maximize its potential

Histone arginine methylation regulates pluripotency in the early mouse embryo

It has been generally accepted that the mammalian embryo starts its development with all cells identical, and only when inside and outside cells form do differences between cells first emerge. However, recent findings show that cells in the mouse embryo can differ in their developmental fate and potency as early as the four-cell stage1,2,3,4. These differences depend on the orientation and order of the cleavage divisions that generated them2,5. Because epigenetic marks are suggested to be involved in sustaining pluripotency6,7, we considered that such developmental properties might be achieved through epigenetic mechanisms. Here we show that modification of histone H3, through the methylation of specific arginine residues, is correlated with cell fate and potency. Levels of H3 methylation at specific arginine residues are maximal in four-cell blastomeres that will contribute to the inner cell mass (ICM) and polar trophectoderm and undertake full development when combined together in chimaeras. Arginine methylation of H3 is minimal in cells whose progeny contributes more to the mural trophectoderm and that show compromised development when combined in chimaeras. This suggests that higher levels of H3 arginine methylation predispose blastomeres to contribute to the pluripotent cells of the ICM. We confirm this prediction by overexpressing the H3-specific arginine methyltransferase CARM1 in individual blastomeres and show that this directs their progeny to the ICM and results in a dramatic upregulation of Nanog and Sox2. Thus, our results identify specific histone modifications as the earliest known epigenetic marker contributing to development of ICM and show that manipulation of epigenetic information influences cell fate determination

Evidence for ground-state electron capture of 40^{40}K

Potassium-40 is a widespread isotope whose radioactivity impacts estimated geological ages spanning billions of years, nuclear structure theory, and subatomic rare-event searches - including those for dark matter and neutrinoless double-beta decay. The decays of this long-lived isotope must be precisely known for its use as a geochronometer, and to account for its presence in low-background experiments. There are several known decay modes for $^{40}$K, but a predicted electron-capture decay directly to the ground state of argon-40 has never been observed, while theoretical predictions span an order of magnitude. The KDK Collaboration reports on the first observation of this rare decay, obtained using a novel combination of a low-threshold X-ray detector surrounded by a tonne-scale, high-efficiency $\gamma$-ray tagger at Oak Ridge National Laboratory. A blinded analysis reveals a distinctly nonzero ratio of intensities of ground-state electron-captures ($I_{\text{EC}^0}$) over excited-state ones ($I_{\text{EC}^*}$) of $I_{\text{EC}^0} / I_{\text{EC}^*}=0.0095\stackrel{\text{stat}}{\pm}0.0022\stackrel{\text{sys}}{\pm}0.0010$ (68% CL), with the null hypothesis rejected at 4$\sigma$ [Stukel et al., DOI:10.1103/PhysRevLett.131.052503]. This unambiguous signal yields a branching ratio of $I_{\text{EC}^0}=0.098\%\stackrel{\text{stat}}{\pm}0.023\%\stackrel{\text{sys}}{\pm}0.010$, roughly half of the commonly used prediction. This first observation of a third-forbidden unique electron capture improves understanding of low-energy backgrounds in dark-matter searches and has implications for nuclear-structure calculations. A shell-model based theoretical estimate for the $0\nu\beta\beta$ decay half-life of calcium-48 is increased by a factor of $7^{+3}_{-2}$. Our nonzero measurement shifts geochronological ages by up to a percent; implications are illustrated for Earth and solar system chronologies.Comment: This is a companion submission to Stukel et al (KDK collaboration) "Rare $^{40}$K decay with implications for fundamental physics and geochronology" [arXiv:2211.10319; DOI: 10.1103/PhysRevLett.131.052503]. As such, both texts share some figures and portions of text. This version updates the text following its review and production proces