cssi/SciSciGPT-SciSciNet huggingface dataset:
The elastic Rayleigh drop

Bioprinting technologies rely on the formation of soft gel drops for printing tissue scaffolds and the dynamics of these drops can affect the process. A model is developed to describe the oscillations of a spherical gel drop with finite shear modulus, whose interface is held by surface tension. The governing elastodynamic equations are derived and a solution is constructed using displacement potentials decomposed into a spherical harmonic basis. The resulting nonlinear characteristic equation depends upon two dimensionless numbers, elastocapillary and compressibility, and admits two types of solutions, (i) spheroidal (or shape change) modes and (ii) torsional (rotational) modes. The torsional modes are unaffected by capillarity, whereas the frequency of shape oscillations depend upon both the elastocapillary and compressibility numbers. Two asymptotic dispersion relationships are derived and the limiting cases of the inviscid Rayleigh drop and elastic globe are recovered. For a fixed polar wavenumber, there exists an infinity of radial modes that each transition from an elasticity wave to a capillary wave upon increasing the elastocapillary number. At the transition, there is a qualitative change in the deformation field and a set of recirculation vortices develop at the free surface. Two special modes that concern volume oscillations and translational motion are characterized. A new instability is documented that reflects the balance between surface tension and compressibility effects due to the elasticity of the drop.
Clustering Motion

Given a set of moving points in ℝd, we show how to cluster them in advance, using a small number of clusters, so that at any time this static clustering is competitive with the optimal k-center clustering at that time. The advantage of this approach is that it avoids updating the clustering as time passes. We also show how to maintain this static clustering efficiently under insertions and deletions.To implement this static clustering efficiently, we describe a simple technique for speeding up clustering algorithms and apply it to achieve faster clustering algorithms for several problems. In particular, we present a linear time algorithm for computing a 2-approximation to the k-center clustering of a set of n points in ℝd. This slightly improves the algorithm of Feder and Greene, that runs in Θ(n log k) time (which is optimal in the algebraic decision tree model).
Three-dimensional observations of grain volume changes during annealing of polycrystalline Ni

Abstract The orientations, locations, and sizes of approximately 2500 grains in a Ni polycrystal were measured at six points in time during an interrupted annealing experiment by synchrotron x-ray based, near field high-energy diffraction microscopy. The volume changes were compared to the geometric characteristics of the grains in both the original microstructures and microstructures in which adjacent twin related domains were merged. Neither the size of a grain nor the number of its nearest neighbors correlates strongly to a grain's volume change over the time scale of this experiment. However, the difference between the number of neighbors a grain has, F, and the average number of neighbors of the neighboring grains have, " open=" F N N , is correlated to the volume change. A grain with more (fewer) neighbors than " open=" F N N usually grows (shrinks). The correlation between the volume change and F - " open=" F N N is obvious only if adjacent twin related domains are merged. The correct sign of the volume change is predicted by F - " open=" F N N about two thirds of the time. The results show that the volume change for a given grain is better predicted by comparing a grain's characteristics to its neighbor's characteristics than to the characteristics of the entire ensemble of grains.
Thermal models of sunspots

We study simple thermal models of sunspots based on the concept of partial inhibition of convection by strong magnetic fields. As in other similar studies (Parker, 1974a; Eschrich and Krause, 1977; Spruit, 1977a), the calculations involve solutions of the heat equation with an appropriate distribution of thermal conductivity. The simplicity of the present model allows a detailed study of the dependence of the solution on the spot parameters, such as the depth of the region in which convection is inhibited. The most important specific results from the model are: (1) the edge of the umbra is sharp, even for deep spots; (2) deep spots produce weak bright rings in the surrounding atmosphere, whereas shallow spots produce intense rings which are difficult to reconcile with observations; (3) only a surface layer of a spot, with thickness of the order of the temperature scale height, is cool. The present model, like those of Eschrich and Krause (1977) and Spruit (1977a) yields surface temperature distributions resembling sunspots. Since the three models all use different descriptions of the convective heat transport, we conclude that the major predictions of the inhibition theory are relatively insensitive to model details.
Cumulative Incidence Ratio

The cumulative incidence rate is a cumulative hazard for a specific disease and should be distinguished from crude (or absolute) risk. Keywords: cumulative incidence rate; cumulative hazard; competing risks; crude risk; absolute risk
Mutation of the ATPase domain of MutS homolog-5 (MSH5) reveals a requirement for a functional MutSγ complex for all crossovers in mammalian meiosis

During meiosis, induction of DNA double strand breaks (DSB) leads to recombination between homologous chromosomes, resulting in crossovers (CO) and non-crossovers (NCO). In the mouse, only 10% of DSBs resolve as COs, mostly through a class I pathway dependent on MutSγ (MSH4/ MSH5) and MutLγ (MLH1/MLH3), the latter representing the ultimate marker of these CO events. A second Class II CO pathway accounts for only a few COs, but is not thought to involve MutSγ/ MutLγ, and is instead dependent on MUS81-EME1. For class I events, loading of MutLγ is thought to be dependent on MutSγ, however MutSγ loads very early in prophase I at a frequency that far exceeds the final number of class I COs. Moreover, loss of MutSγ in mouse results in apoptosis before CO formation, preventing the analysis of its CO function. We generated a mutation in the ATP binding domain of Msh5 (Msh5GA). While this mutation was not expected to affect MutSγ complex formation, MutSγ foci do not accumulate during prophase I. However, most spermatocytes from Msh5GA/GA mice progress to late pachynema and beyond, considerably further than meiosis in Msh5−/− animals. At pachynema, Msh5GA/GA spermatocytes show persistent DSBs, incomplete homolog pairing, and fail to accumulate MutLγ. Unexpectedly, Msh5GA/GA diakinesis-staged spermatocytes have no chiasmata at all from any CO pathway, indicating that a functional MutSγ complex is critical for all CO events regardless of their mechanism of generation.
Optimal staged self-assembly of linear assemblies

We analyze the complexity of building linear assemblies, sets of linear assemblies, and \(\mathcal {O}(1)\)-scale general shapes in the staged tile assembly model. For systems with at most b bins and t tile types, we prove that the minimum number of stages to uniquely assemble a \(1 \times n\) line is \(\varTheta (\log _t{n} + \log _b{\frac{n}{t}} + 1)\). Generalizing to \(\mathcal {O}(1) \times n\) lines, we prove the minimum number of stages is \(\mathcal {O}(\frac{\log {n} - tb - t\log t}{b^2} + \frac{\log \log b}{\log t})\) and \(\varOmega (\frac{\log {n} - tb - t\log t}{b^2})\).
Collective dynamics of semidilute polyelectrolyte solutions with salt

We present a theory of coupled fluctuations of polymer segments, counterions, and coions in semidilute polyelectrolyte solutions containing added salt. The coupling among the three species results in three relaxation modes, instead of the previous common usage of only two relaxation modes by absorbing the role of salt as an effective solvent. Among the three modes, one is the nondiffusive plasmon mode and the other two are diffusive modes. These three modes are unrelated to any other slow mode that may arise from effects such as aggregation. Explicit expressions are derived for the decay rates in terms of concentrations of polyelectrolyte and salt, and the degree of ionization of the polymer. The specific values for the decay rates of the three modes are shown as an illustration for a chosen set of values of experimental variables. In the absence of added salt, the present theory reduces to the previous theory of fast diffusion in salt‐free polyelectrolyte solutions and to the Nernst–Hartley theory for simple electrolytes. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019, 57, 1263–1269
Multi-robot informative path planning in unknown environments through continuous region partitioning:

We consider the NP-hard problem of multirobot informative path planning in the presence of communication constraints, where the objective is to collect higher amounts of information of an ambient p...
Preparation of (Fluoromethyl)- and (Difluoromethyl)imidazoles

2-(Fluoromethyl)- and 2-(difluoromethyl)imidazoles, and 4-(fluoromethyl)- and 4-(difluoromethyl)imidazoles have been prepared by deoxyfluorination of (hydroxymethyl)imidazole or formylimidazole precursors.
SYNTHESES OF DIALKYL AND FUNCTIONALIZED KETONES VIA 1-(BENZOTRIAZOL-1-YL)ALKYL METHYL THIOETHERS

Benzotriazol-1-ylmethyl methyl thioether (1), after easy deprotonation by BuLi, reacted with alkyl halides to afford 1-(benzotriazol-1-yl)alkyl methyl thioethers 2 in good yields. The utility of compounds 2 as alkanoyl anion equivalents was demonstrated by the reactions of their anions with alkyl halides, aldehydes, ketones, esters, and phenyl isocyanate: the products were readily hydrolyzed to α-functionalized ketones in dilute aqueous acid.
Brain regions modulated during covert visual attention in the macaque

Neurophysiological studies of covert visual attention in monkeys have emphasized the modulation of sensory neural responses in the visual cortex. At the same time, electrophysiological correlates of attention have been reported in other cortical and subcortical structures, and recent fMRI studies have identified regions across the brain modulated by attention. Here we used fMRI in two monkeys performing covert attention tasks to reproduce and extend these findings in order to help establish a more complete list of brain structures involved in the control of attention. As expected from previous studies, we found attention-related modulation in frontal, parietal and visual cortical areas as well as the superior colliculus and pulvinar. We also found significant attention-related modulation in cortical regions not traditionally linked to attention – mid-STS areas (anterior FST and parts of IPa, PGa, TPO), as well as the caudate nucleus. A control experiment using a second-order orientation stimulus showed that the observed modulation in a subset of these mid-STS areas did not depend on visual motion. These results identify the mid-STS areas (anterior FST and parts of IPa, PGa, TPO) and caudate nucleus as potentially important brain regions in the control of covert visual attention in monkeys.
Cell-type-Specific Patterned Stimulus-Independent Neuronal Activity in the Drosophila Visual System during Synapse Formation.

Summary Stereotyped synaptic connections define the neural circuits of the brain. In vertebrates, stimulus-independent activity contributes to neural circuit formation. It is unknown whether this type of activity is a general feature of nervous system development. Here, we report patterned, stimulus-independent neural activity in the Drosophila visual system during synaptogenesis. Using in vivo calcium, voltage, and glutamate imaging, we found that all neurons participate in this spontaneous activity, which is characterized by brain-wide periodic active and silent phases. Glia are active in a complementary pattern. Each of the 15 of over 100 specific neuron types in the fly visual system examined exhibited a unique activity signature. The activity of neurons that are synaptic partners in the adult was highly correlated during development. We propose that this cell-type-specific activity coordinates the development of the functional circuitry of the adult brain.
Photoluminescence and Magnetism in the New Magnetic Semiconductors: K2Cd3(1-x)Mn3xS4

A new family of magnetic semiconductors, K2Cd3(1-x)Mn3xS4, prepared from molten K2Sx is reported. For x ≤ 0.6, the compounds crystallize in the K2Cd3S4 structure type. The cell volumes of the series obey Vegard's Law for solid solutions. The compounds range in color from yellow through orange brown to red and possess platelike morphologies. A structural transformation occurs between x = 0.7 and x = 0.9. Red plates of K2Cd0.4Mn2.6S4 (x = 0.87) crystallize in the space group Ccca with a = 5.9217(8) A, b = 13.531(1) A, c = 11.0696(8) A, and V = 887.0(1) A3. The end member, K2Mn3S4, crystallizes in the space group Ccca with a = 11.0637(7) A, b = 26.830(2) A c = 5.8180(4) A, and V = 1727 A3. For x ≤ 0.6, the compounds form as (M3S4)n2n- layers, interspersed by K+ cations. These layers are composed only of M3S42- units shaped like truncated cubes. When x = 0.87, a new structure related to that of Cs2Mn3S4 is observed. The end member of the series (i.e., x = 1) K2Mn3S4 is revealed to have a related yet surprisin...
Preparation of 3e,4,5,6e,7,8-hexahydro[2.2]paracyclophane

Abstract 3e,4,5,6e,7,8-Hexahydro[2.2]paracyclophane (11) was prepared through a coupling reaction to form dithiacyclophane, oxidation to yield the sulfone followed by the pyrolysis. It is noteworthy that the methine hydrogen in the rigid structures 5 and 11 toward to the center of the benzene ring leading to high field shifts resonance appear at δ −0.72 and −2.32 ∼ −2.41.
Asymmetric [4+3] cycloadditions from chiral α-chloro imines

Abstract The first asymmetric [4+3] cycloadditions of 2-aminoallyl cations derived from chiral α-chloro imines to furan and pyrrole systems are reported. The absolute configuration of the major enantiomer of the bicyclic ketone 4a derived from the cycloadducts has been elucidated, and possible rationales for the observed stereoselectivity are discussed.
Portfolio selection for individual passive investing

This paper considers passive fund selection from an individual investor’s perspective. The growth of the passive fund market over the past decade is staggering. Individual investors who wish to buy these funds for their retirement and brokerage accounts have many options and are faced with a difficult selection problem. Which funds do they invest in, and in what proportions? We develop a novel statistical methodology to address this problem. A Bayesian decision-theoretic approach is presented to construct optimal sparse portfolios for individual investors over time.
Convenient Access to Primary Amines by Employing the Barbier-Type Reaction of N-(Trimethylsilyl)imines Derived from Aromatic and Aliphatic Aldehydes

A new versatile preparation of primary amines via benzylation of aromatic and aliphatic aldimines is described. Sonochemical and traditional methods for generation of the reactive intermediates are compared and contrasted. Competitive reactions were analyzed via free energy relationships to support the proposed alkylative mechanism.
Maleimido Derivatives of Diethylenetriaminepentaacetic Acid and Triethylenetetraaminehexaacetic Acid: Their Synthesis and Potential for Specific Conjugation with Biomolecules

Immunoconjugates sometimes suffer changes in immunoreactivity and tumor targeting because the chelators used interfere with antigen binding. To try to circumvent such problems, two new homobifunctional chelating agents, 2,6-bis[p-[(beta-maleimidopropionyl) amino]benzyl]diethylenetriamine- N,N,N',N",N"-pentaacetic acid (MPBz-DTPA) and 2,9-bis [p-(beta-maleimidopropionyl)amino]benzyl] triethylenetetraamine-N,N,N',N',N",N"-hexaacetic acid (MPBz-TTHA), were synthesized for chelation of 111In and 90Y metal ions. Each of the new chelators contains two maleimido functional groups substituted at the carbon backbone. In this study, the overall chemical yields for MPBz-DTPA and MPBz-TTHA were approximately 5 and 4%, respectively. The intermediate and final compounds were purified by flash chromatography and fully characterized by 1H-NMR, 13C-NMR, and mass spectroscopy. Chemical modification of the maleimido group on each of these derivatives allowed specific conjugation with a sulfhydryl group at the hinge region of an antibody molecule and conjugation with other peptides. For instance, the two Fab' fragments, through their hinge-region sulfhydryl groups, could covalently attach to a homobifunctional chelator via thioether linkage to generate a Fab'-S-chelator-S-Fab' immunoconjugate. By design, immunoconjugates containing these new chelators will contain only one chelator derivative at a known region of antibody away from the antigen binding site. Consequently, these chelators may minimize changes in the immunoreactivity and improve tumor targeting of immunoconjugates that contain them.
Cell size–dependent regulation of Wee1 localization by Cdr2 cortical nodes

Cell size control requires mechanisms that link cell growth with Cdk1 activity. In fission yeast, the protein kinase Cdr2 forms cortical nodes that include the Cdk1 inhibitor Wee1 along with the Wee1-inhibitory kinase Cdr1. We investigated how nodes inhibit Wee1 during cell growth. Biochemical fractionation revealed that Cdr2 nodes were megadalton structures enriched for activated Cdr2, which increases in level during interphase growth. In live-cell total internal reflection fluorescence microscopy videos, Cdr2 and Cdr1 remained constant at nodes over time, but Wee1 localized to nodes in short bursts. Recruitment of Wee1 to nodes required Cdr2 kinase activity and the noncatalytic N terminus of Wee1. Bursts of Wee1 localization to nodes increased 20-fold as cells doubled in size throughout G2. Size-dependent signaling was caused in part by the Cdr2 inhibitor Pom1, which suppressed Wee1 node bursts in small cells. Thus, increasing Cdr2 activity during cell growth promotes Wee1 localization to nodes, where inhibitory phosphorylation of Wee1 by Cdr1 and Cdr2 kinases promotes mitotic entry.
Synthesis of derivatives of thiophene using methyl 2‐isothiocyanatobenzoate

A variety of 2-substituted thiophenes is readily obtained from 2-(2-thienyl)-4H-3,l-benzothiazin-4-one (2), which is formed when thiophene reacts with methyl 2-isothiocyanatobenzoate (1) in the presence of anhydrous stannic chloride.
Differentiation between 1,2,4,5-tetraoxanes and 1,2,4,5,7,8-hexaoxonanes using 1H and 13C NMR analyses

The proton and carbon resonance spectra of ten pairs of 1,2,4,5-tetraoxanes and 1,2,4,5,7,8-hexa-oxonanes derived from acyclic and cyclic ketones have been recorded. A reliable method for distinguishing between 1,2,4,5-tetraoxanes and 1,2,4,5,7,8-hexaoxonanes by inspection of their chemical shifts, signal number, signal shape, and dynamic features has been developed. This method provides a rapid structural assignment of 1,2,4,5-tetraoxanes and 1,2,4,5,7,8-hexaoxonanes without using vapor pressure osmometry, isotope labeling or low temperature NMR techniques.
Enolization Enthalpies for Aliphatic Carbonyl and Thiocarbonyl Compounds

The enolization enthalpies at 0 and 298 K for nine aliphatic carbonyl and nine aliphatic thiocarbonyl compounds have been determined from ab initio CBS-4 (complete basis set fourth-order) model calculations. The enolization enthalpies for the aliphatic carbonyl compounds were found to be 9−24 kcal/mol, but they were about 8−11 kcal/mol higher than those for the corresponding thiocarbonyl compounds. The lower enolization enthalpies for the thiocarbonyl compounds are attributed to the >CS being much weaker than the >CO double bond strength. The enolization enthalpies for the cycloketones and thiocycloketones were found to be significantly dependent upon the size of the cyclic ring. The solvent effects on the enolization enthalpy have also been discussed.
Synthesis of lipidic tamoxifen

Abstract We describe a general method for elaboration of the ethyl sidechain of tamoxifen and its primary 4-hydroxy metabolite. Novel lipidic tamoxifen and a functionalized B-ring analog were synthesized from a common stilbene oxide intermediate for potential liposomal applications including estrogen receptor targeting.
An improved procedure for the nitration of benzo-2,1,3-selenadiazoles and their reduction to ortho-phenylenediamines

A method for the nitration of benzo-2,1,3-selenadiazoles using nitric acid dissolved in a mixture of methanesulfonic acid and phosphorus pentoxide at room temperature is presented. The SN2Ar displacement of fluoride that is observed when sulfuric acid is used as solvent is prevented and yields are high. Sodium nitrate could be used in place of nitric acid with no loss in yield. Following nitration, the 2,1,3-selenadiazole ring is cleaved with hydriodic acid to afford a 3-nitro-ortho-phenylenediamine. The method is applied to the multi-gram preparation of 4-fluoro-3-nitrobenzene-1,2-diamine.
Direct and indirect band gap types in one-dimensional conjugated or stacked organic materials

Whether a semiconductor has a direct or an indirect band gap is important in determining physical properties such as photoconductivity and electroluminescence. For one-dimensional conjugated polymeric semiconductors, as well as organic molecular crystals, we show how the band gap type (direct or indirect) is determined by the shapes of the HOMO and the LUMO of constituent monomeric conjugated molecules. The connectivity of the monomer units, and the topology of orbital interaction determine the band gap type. Pairing symmetry in the π electronic system of even alternant hydrocarbons allows the immediate prediction of the band gap type, direct or indirect, by examining only the structures of the monomer units and their connectivity in polymers or molecular stacks.
Synthesis of catalytic materials on multiple length scales: from mesoporous to macroporous bulk mixed metal oxides for selective oxidation of hydrocarbons

A short review is provided of the principles guiding the synthesis of mesoporous and macroporous bulk mixed metal oxides on multiple length scales in the presence of surfactant mesophases and colloidal arrays of monodisperse spheres, respectively. Emerging catalytic applications of these novel bulk metal oxide phases in selective oxidation of hydrocarbons are described and discussed.
Genome Sequence of Jaltomata Addresses Rapid Reproductive Trait Evolution and Enhances Comparative Genomics in the Hyper-Diverse Solanaceae

Within the economically important plant family Solanaceae, Jaltomata is a rapidly evolving genus that has extensive diversity in flower size and shape, as well as fruit and nectar color, among its ∼80 species. Here, we report the whole-genome sequencing, assembly, and annotation, of one representative species (Jaltomata sinuosa) from this genus. Combining PacBio long reads (25×) and Illumina short reads (148×) achieved an assembly of ∼1.45 Gb, spanning ∼96% of the estimated genome. Ninety-six percent of curated single-copy orthologs in plants were detected in the assembly, supporting a high level of completeness of the genome. Similar to other Solanaceous species, repetitive elements made up a large fraction (∼80%) of the genome, with the most recently active element, Gypsy, expanding across the genome in the last 1-2 Myr. Computational gene prediction, in conjunction with a merged transcriptome data set from 11 tissues, identified 34,725 protein-coding genes. Comparative phylogenetic analyses with six other sequenced Solanaceae species determined that Jaltomata is most likely sister to Solanum, although a large fraction of gene trees supported a conflicting bipartition consistent with substantial introgression between Jaltomata and Capsicum after these species split. We also identified gene family dynamics specific to Jaltomata, including expansion of gene families potentially involved in novel reproductive trait development, and loss of gene families that accompanied the loss of self-incompatibility. This high-quality genome will facilitate studies of phenotypic diversification in this rapidly radiating group and provide a new point of comparison for broader analyses of genomic evolution across the Solanaceae.
Modular Mo-based catalysts for efficient asymmetric olefin metathesis. Catalytic enantioselective synthesis of cyclic ethers and acetals

Abstract Chiral Mo-based complexes 1 – 3 promote the catalytic enantioselective ring-closing metathesis of various polyenes to afford unsaturated furans, pyrans and siloxanes efficiently and in high ee (70–98% ee). The structural modularity of this class of chiral catalysts plays a critical role in these studies. Modification of the diolate or imido moities of these chiral catalysts gives rise to a range of complexes that can be screened for higher reactivity and/or enantioselectivity.
xCell: digitally portraying the tissue cellular heterogeneity landscape

Tissues are complex milieus consisting of numerous cell types. Several recent methods have attempted to enumerate cell subsets from transcriptomes. However, the available methods have used limited sources for training and give only a partial portrayal of the full cellular landscape. Here we present xCell, a novel gene signature-based method, and use it to infer 64 immune and stromal cell types. We harmonized 1822 pure human cell type transcriptomes from various sources and employed a curve fitting approach for linear comparison of cell types and introduced a novel spillover compensation technique for separating them. Using extensive in silico analyses and comparison to cytometry immunophenotyping, we show that xCell outperforms other methods. xCell is available at http://xCell.ucsf.edu/ .
NMR spectroscopy as a tool to investigate the structural basis of anticancer drugs.

NMR spectroscopy has been shown to be useful in determining the structures of nucleic acid fragments in solution. Over the last several years NMR spectroscopy, in conjunction with restrained molecular dynamics, has been employed to understand the 3D structures of a number of anticancer drugs and to rationalize their DNA binding behavior. In this review we address the methodologies used most frequently to determine nucleic acid structures in solution. In subsequent sections, we examine how these methods have been applied to rationalize the activities of a number of anticancer agents that target duplex DNA such as cisplatin, bleomycin and calicheamicin. Non-duplexe DNA and RNA also represent interesting nucleic acid targets for anticancer drug design and applications of solution NMR spectroscopy to understanding the structures of these types of molecules (e.g. Okazaki fragments, DNA tetraplexes) are also reviewed. In the final sections, advances in NMR methodologies (e.g. linear prediction, superconducting probes) that are likely to impact the research conducted in this aera are reviewed. The success of NMR spectroscopy in understanding the structural basis for clinically usefull anticancer drugs bodes well for future applications of this methodology not only in rationalization of existing biological activity, but in the design of novel agents that will be useful in treating neoplastic disease
Phosphomolybdate clusters as molecular building blocks in the design of one-, two- and three-dimensional organic–inorganic hybrid materials

Abstract An attractive approach to the design of inorganic solids exploits the tethering of inorganic clusters through organic spacers to produce hybrid materials with composite properties. We have recently described a modified strategy in which polyoxometalate clusters are linked through organic subunits to give an anionic hybrid substructure which may be further modified through the introduction of secondary metal–ligand complex (SMLC) cations, serving as a third component building block. In this application, the molybdophosphonate cluster {Mo 5 O 15 (O 3 PR) 2 } 4− serves as a secondary building unit (SBU) with alkyl (CH 2 ) n or aromatic –(C 6 H 4 ) n – tethers providing one-dimensional structural expansion. A binucleating ligand such as tetrapyridylpyrazine (tpyprz) is used to bridge secondary metal sites into a binuclear {Cu 2 (tpyprz)} 4+ SBU which may link phosphomolybdate clusters into two- or three-dimensional structures. The influence of a variety of structural determinants is discussed, including the tether length of the diphosphonate ligand, the coordination preferences of the secondary metal, expansion of the ligand component of the SMLC, and substitution of As for P in the oxide SBU.
Vinylboranes are omniphilic dienophiles. Some unusual and useful properties of vinylboranes in diels-alder reactions

Abstract The rate of Diels-Alder reactions with vinyl-9-BBN is uniquely insensitive to diene substituent effects, and high reactivity is observed with both electron-rich and electron-poor dienes. The regioselectivity of these reactions is controlled mainly by steric effects.
Higher-Order Thalamic Circuits Channel Parallel Streams of Visual Information in Mice.

Summary Higher-order thalamic nuclei, such as the visual pulvinar, play essential roles in cortical function by connecting functionally related cortical and subcortical brain regions. A coherent framework describing pulvinar function remains elusive because of its anatomical complexity and involvement in diverse cognitive processes. We combined large-scale anatomical circuit mapping with high-density electrophysiological recordings to dissect a homolog of the pulvinar in mice, the lateral posterior thalamic nucleus (LP). We define three broad LP subregions based on correspondence between connectivity and functional properties. These subregions form corticothalamic loops biased toward ventral or dorsal stream cortical areas and contain separate representations of visual space. Silencing the visual cortex or superior colliculus revealed that they drive visual tuning properties in separate LP subregions. Thus, by specifying the driving input sources, functional properties, and downstream targets of LP circuits, our data provide a roadmap for understanding the mechanisms of higher-order thalamic function in vision.
An efficient synthetic approach to aza-C-glycosyl compounds. Application to the synthesis of an aza-C-disaccharide

Abstract The NIS-mediated cyclization of aminoheptenitols 5–8 (prepared in three steps from tetra- O -benzyl- d -hexopyranoses ) provided 1,2,6-trideoxy-2,6-imino-liodoheptitol derivatives 9–12, respectively, highly stereoselectively and in high yield. The “ α- d - gluco ” epimer 9 was used in the synthesis of a precursor of an aza-C-disacharide and its reaction with triethyl phosphite was investigated.
Profiling the genome-wide landscape of tandem repeat expansions

Tandem repeat (TR) expansions have been implicated in dozens of genetic diseases, including Huntington's Disease, Fragile X Syndrome, and hereditary ataxias. Furthermore, TRs have recently been implicated in a range of complex traits, including gene expression and cancer risk. While the human genome harbors hundreds of thousands of TRs, analysis of TR expansions has been mainly limited to known pathogenic loci. A major challenge is that expanded repeats are beyond the read length of most next-generation sequencing (NGS) datasets and are not profiled by existing genome-wide tools. We present GangSTR, a novel algorithm for genome-wide genotyping of both short and expanded TRs. GangSTR extracts information from paired-end reads into a unified model to estimate maximum likelihood TR lengths. We validate GangSTR on real and simulated data and show that GangSTR outperforms alternative methods in both accuracy and speed. We apply GangSTR to a deeply sequenced trio to profile the landscape of TR expansions in a healthy family and validate novel expansions using orthogonal technologies. Our analysis reveals that healthy individuals harbor dozens of long TR alleles not captured by current genome-wide methods. GangSTR will likely enable discovery of novel disease-associated variants not currently accessible from NGS.
Preparation of Hydantoins by Catalytic Oxidative Carbonylation of α-Amino Amides

Hydantoins can be synthesized from the corresponding amino amides employing oxidative catalytic carbonylation using W(CO)6 as the catalyst, I2 as the oxidant, CO as the carbonyl source, and DBU as ...
Speciation as a sieve for ancestral polymorphism

Because they are considered rare, balanced polymorphisms are often discounted as crucial constituents of genome-wide variation in sequence diversity. Despite its perceived rarity, however, long-term balancing selection can elevate genetic diversity and significantly affect observed divergence between species. Here, we discuss how ancestral balanced polymorphisms can be "sieved" by the speciation process, which sorts them unequally across descendant lineages. After speciation, ancestral balancing selection is revealed by genomic regions of high divergence between species. This signature, which resembles that of other evolutionary processes, can potentially confound genomic studies of population divergence and inferences of "islands of speciation."
Substituent effects in the design of new organic NLO materials

Several approaches have been suggested during the past few years for increasing third order nonlinearity in organic compounds. In general, these have focused on manipulation of the effective conjugation length of the pi-electron framework to maximize orbital overlap. It has only recently become apparent that substituent effects, which affect the overall electron density distribution, may be an extremely effective way of enhancing nonlinearity. In this study we review known substituent effects on nonlinearity, and suggest how donor-donor, acceptor- acceptor, and donor-acceptor interaction can be utilized in the design of molecules and polymers with enhanced nonlinearity.© (1992) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
A remarkable accelerating effect of Ag-salt on intramolecular cyclization of o-(1-alkynyl)benzenesulfonamides.

Herein, we report transition metal-catalyzed intramolecular cyclization of o-(1-alkynyl)benzenesulfonamides to afford 3-substituted benzothiazines regioselectively via a C−N bond forming reaction and Cu-catalyzed sequential C−N and C−C bond formation leading to the corresponding 3,4-disubstituted derivatives.
The interplay of demography and selection during maize domestication and expansion

The history of maize has been characterized by major demographic events, including population size changes associated with domestication and range expansion, and gene flow with wild relatives. The interplay between demographic history and selection has shaped diversity across maize populations and genomes. We investigate these processes using high-depth resequencing data from 31 maize landraces spanning the pre-Columbian distribution of maize, and four wild teosinte individuals (Zea mays ssp. parviglumis). Genome-wide demographic analyses reveal that maize experienced pronounced declines in effective population size due to both a protracted domestication bottleneck and serial founder effects during post-domestication spread, while parviglumis in the Balsas River Valley experienced population growth. The domestication bottleneck and subsequent spread led to an increase in deleterious alleles in the domesticate compared to the wild progenitor. This cost is particularly pronounced in Andean maize, which has experienced a more dramatic founder event compared to other maize populations. Additionally, we detect introgression from the wild teosinte Zea mays ssp. mexicana into maize in the highlands of Mexico, Guatemala, and the southwestern USA, which reduces the prevalence of deleterious alleles likely due to the higher long-term effective population size of teosinte. These findings underscore the strong interaction between historical demography and the efficiency of selection and illustrate how domesticated species are particularly useful for understanding these processes. The landscape of deleterious alleles and therefore evolutionary potential is clearly influenced by recent demography, a factor that could bear importantly on many species that have experienced recent demographic shifts.
Synthesis of a model for the xestobergsterol D and E rings using the Pauson-Khand reaction

Abstract An intramolecular Pauson-Khand reaction has been used to illustrate the incorporation of proper stereochemistry at the C/D/E rings of a xestobergsterol model system.
In vivo ultrasound-switchable fluorescence imaging

The conventional fluorescence imaging has limited spatial resolution in centimeter-deep tissue because of the tissue's high scattering property. Ultrasound-switchable fluorescence (USF) imaging, a new imaging technique, was recently proposed to realize high-resolution fluorescence imaging in centimeter-deep tissue. However, in vivo USF imaging has not been achieved so far because of the lack of stable near-infrared contrast agents in a biological environment and the lack of data about their biodistributions. In this study, for the first time, we achieved in vivo USF imaging successfully in mice with high resolution. USF imaging in porcine heart tissue and mouse breast tumor via local injections were studied and demonstrated. In vivo and ex vivo USF imaging of the mouse spleen via intravenous injections was also successfully achieved. The results showed that the USF contrast agent adopted in this study was very stable in a biological environment, and it was mainly accumulated into the spleen of the mice. By comparing the results of CT imaging and the results of USF imaging, the accuracy of USF imaging was proved.
Dendrite Suppression by Shock Electrodeposition in Charged Porous Media.

It is shown that surface conduction can stabilize electrodeposition in random, charged porous media at high rates, above the diffusion-limited current. After linear sweep voltammetry and impedance spectroscopy, copper electrodeposits are visualized by scanning electron microscopy and energy dispersive spectroscopy in two different porous separators (cellulose nitrate, polyethylene), whose surfaces are modified by layer-by-layer deposition of positive or negative charged polyelectrolytes. Above the limiting current, surface conduction inhibits growth in the positive separators and produces irregular dendrites, while it enhances growth and suppresses dendrites behind a deionization shock in the negative separators, also leading to improved cycle life. The discovery of stable uniform growth in the random media differs from the non-uniform growth observed in parallel nanopores and cannot be explained by classic quasi-steady “leaky membrane” models, which always predict instability and dendritic growth. Instead, the experimental results suggest that transient electro-diffusion in random porous media imparts the stability of a deionization shock to the growing metal interface behind it. Shock electrodeposition could be exploited to enhance the cycle life and recharging rate of metal batteries or to accelerate the fabrication of metal matrix composite coatings.
A Brief Note on Charge Quantization from Fractal Distributions

This brief note points out that classical Maxwell equations on fractal distributions can accommodate fractional magnetic charges . Although these fractional objects are un-observable at energy scales significantly lower than the electroweak scale, their cumulative contribution may become relevant for charge quantization in Dirac’s theory of magnetic monopoles.
Size consistent excited states via algorithmic transformations between variational principles

We demonstrate that a broad class of excited state variational principles is not size consistent. In light of this difficulty, we develop and test an approach to excited state optimization that transforms between variational principles to achieve state selectivity, size consistency, and compatibility with quantum Monte Carlo. To complement our formal analysis, we provide numerical examples that confirm these properties and demonstrate how they contribute to a more black box approach to excited states in quantum Monte Carlo.
The multiplicative ideal theory of Leavitt path algebras

Abstract It is shown that every Leavitt path algebra L of an arbitrary directed graph E over a field K is an arithmetical ring, that is, the distributive law A ∩ ( B + C ) = ( A ∩ B ) + ( A ∩ C ) holds for any three two-sided ideals of L. It is also shown that L is a multiplication ring, that is, given any two ideals A , B in L with A ⊆ B , there is always an ideal C such that A = B C , an indication of a possible rich multiplicative ideal theory for L. Existence and uniqueness of factorization of the ideals of L as products of special types of ideals such as prime, irreducible or primary ideals is investigated. The irreducible ideals of L turn out to be precisely the primary ideals of L. It is shown that an ideal I of L is a product of finitely many prime ideals if and only the graded part g r ( I ) of I is a product of prime ideals and that I / g r ( I ) is finitely generated with a generating set of cardinality no more than the number of distinct prime ideals in the prime factorization of g r ( I ) . As an application, it is shown that if E is a finite graph, then every ideal of L is a product of prime ideals. The same conclusion holds if L is two-sided artinian or two-sided noetherian. Examples are constructed verifying whether some of the well-known theorems in the ideal theory of commutative rings such as the Cohen's theorem on prime ideals and the characterizing theorem on ZPI rings hold for Leavitt path algebras.
On Koszul duality for Kac-Moody groups

For any Kac-Moody group G with Borel B, we give a monoidal equivalence between the derived category of B-equivariant mixed complexes on the flag variety G/B and (a certain completion of) the derived category of G∨monodromic mixed complexes on the enhanced flag variety G∨/U∨, here G∨ is the Langlands dual of G. We also prove variants of this equivalence, one of which is the equivalence between the derived category of U-equivariant mixed complexes on the partial flag variety G/P and a certain “Whittaker model” category of mixed complexes on G∨/B∨. In all these equivalences, intersection cohomology sheaves correspond to (free-monodromic) tilting sheaves. Our results generalize the Koszul duality patterns for reductive groups in [BGS96].
Centers of cyclotomic Sergeev superalgebras

Abstract We prove that the natural map from the center of the affine Sergeev superalgebra to the even center of any cyclotomic Sergeev superalgebra of odd level is surjective, hence that the even center of a cyclotomic Sergeev superalgebra of odd level consists of symmetric functions in the squares of its polynomial generators.
Genus Integration, Abelianization, and Extended Monodromy

Given a Lie algebroid we discuss the existence of a smooth abelian integration of its abelianization. We show that the obstructions are related to the extended monodromy groups introduced recently in \cite{CFMb}. We also show that this groupoid can be obtained by a path-space construction, similar to the Weinstein groupoid of \cite{CF1}, but where the underlying homotopies are now supported in surfaces with arbitrary genus. As an application, we show that the prequantization condition for a (possibly non-simply connected) manifold is equivalent to the smoothness of an abelian integration. Our results can be interpreted as a generalization of the classical Hurewicz theorem.
Benedicks' theorem for the Weyl transform

Abstract If the set of points where a function is nonzero is of finite measure, and its Weyl transform is a finite rank operator, then the function is identically zero.
Associative Memory Using Dictionary Learning and Expander Decoding

An associative memory is a framework of content-addressable memory that stores a collection of message vectors (or a dataset) over a neural network while enabling a neurally feasible mechanism to recover any message in the dataset from its noisy version. Designing an associative memory requires addressing two main tasks: 1) learning phase: given a dataset, learn a concise representation of the dataset in the form of a graphical model (or a neural network), 2) recall phase: given a noisy version of a message vector from the dataset, output the correct message vector via a neurally feasible algorithm over the network learnt during the learning phase. This paper studies the problem of designing a class of neural associative memories which learns a network representation for a large dataset that ensures correction against a large number of adversarial errors during the recall phase. Specifically, the associative memories designed in this paper can store dataset containing exp( n ) n -length message vectors over a network with O ( n ) nodes and can tolerate Ω( n / polylog) adversarial errors. This paper carries out this memory design by mapping the learning phase and recall phase to the tasks of dictionary learning with a square dictionary and iterative error correction in an expander code, respectively.
The absolutely continuous spectrum of Jacobi matrices

I explore some consequences of a groundbreaking result of Brei- messer and Pearson on the absolutely continuous spectrum of one-dimensional Schrodinger operators. These include an Oracle Theorem that predicts the potential and rather general results on the approach to certain limit potentials. In particular, we prove a Denisov-Rakhmanov type theorem for the general nite gap case. The main theme is the following: It is extremely dicult to produce abso- lutely continuous spectrum in one space dimension and thus its existence has strong implications.
The Age of Information in Multihop Networks

Information updates in multihop networks such as Internet of Things (IoT) and intelligent transportation systems have received significant recent attention. In this paper, we minimize the age of a single information flow in interference-free multihop networks. When preemption is allowed and the packet transmission times are exponentially distributed, we prove that a preemptive last-generated, first-served (LGFS) policy results in smaller age processes across all nodes in the network than any other causal policy (in a stochastic ordering sense). In addition, for the class of new-better-than-used (NBU) distributions, we show that the non-preemptive LGFS policy is within a constant age gap from the optimum average age. In contrast, our numerical result shows that the preemptive LGFS policy can be very far from the optimum for some NBU transmission time distributions. Finally, when preemption is prohibited and the packet transmission times are arbitrarily distributed, the non-preemptive LGFS policy is shown to minimize the age processes across all nodes in the network among all work-conserving policies (again in a stochastic ordering sense). Interestingly, these results hold under quite general conditions, including 1) arbitrary packet generation and arrival times, and 2) for minimizing both the age processes in stochastic ordering and any non-decreasing functional of the age processes.