cssi/SciSciGPT-SciSciNet huggingface dataset:
A NOVEL ROUTE TO MONOANOMERIC SPIROKETALS

A series of spiroketal C2-acetals was treated with an alkylsilane reagent in the presence of either TMSOTf or BF3.OEt2 to effect C2-substitution. Regioselective alkylation was successful, but in each case a monoanomeric spiroketal was the unexpected major product. The sequence provides a model for the synthesis of the CD subunit of altohyrtin A.
A Connectome Wide Functional Signature of Transdiagnostic Risk for Mental Illness

Abstract Background High rates of comorbidity, shared risk, and overlapping therapeutic mechanisms have led psychopathology research toward transdiagnostic dimensional investigations of clustered symptoms. One influential framework accounts for these transdiagnostic phenomena through a single general factor, sometimes referred to as the p factor, associated with risk for all common forms of mental illness. Methods We build on previous research identifying unique structural neural correlates of the p factor by conducting a data-driven analysis of connectome-wide intrinsic functional connectivity (n = 605). Results We demonstrate that higher p factor scores and associated risk for common mental illness maps onto hyperconnectivity between visual association cortex and both frontoparietal and default mode networks. Conclusions These results provide initial evidence that the transdiagnostic risk for common forms of mental illness is associated with patterns of inefficient connectome-wide intrinsic connectivity between visual association cortex and networks supporting executive control and self-referential processes, networks that are often impaired across categorical disorders.
Novel antifungal 2-aryl-1-(1H-1,2,4-triazol-1-yl)butan-2-ol derivatives with high activity against Aspergillus fumigatus

Abstract Replacement of one triazole ring of fluconazole with 4-pyridinyl leads to an increase in activity against Aspergillus fumigatus. Introduction of an α-methyl group has a marked additional beneficial effect. Investigation of pyridinyl and pyrimidinyl analogues resulted in the identification of 30 (UK-109, 496, voriconazole) which has excellent potency against a broad range of fungal pathogens including A. fumigatus and Candida krusei.
Chirality amplification--the accumulation principle revisited.

The chirality amplification mechanism proposed by Yamagata in 1966, relying on an Accumulation Principle which involved the parity violating energy difference (1 + e) presumed to be operative at each step in the formation of a homochiral biopolymer, is briefly surveyed historically. The Accumulation Principle is then examined analytically and found to be incapable of producing a unique homochiral polymer in any realistic polymerization process. The extension of the Accumulation Principle to crystallizations which afford enantiomorphic crystals is also scrutinized and found to be misapplied and invalid.
Reaction of naphthalene‐2,3‐dicarbaldehyde with cyanide; A unique oxidative condensation product

Naphthalene-2,3-dicarbaldehyde (NDA), a reagent used for the fluorescent detection of amino acids in the presence of cyanide, self-condenses in the presence of cyanide ion and methanol at room temperature to yield a unique crystalline product 2, 15-hydroxybenzo[g]benzo[6,7]isochromeno[4,3-c]isochromen-7(15H)-one. The product is proposed to result from facile air oxidation of NDA to a methyl ester in combination with benzoin condensation. Product 2 does not to form in the absence of air. The gHMBC spectrum of 2 distinguishes it from a possible alternative isomeric condensation product.
DESIGN AND DIVERSITY ANALYSIS OF LARGE COMBINATORIAL LIBRARIES USING CELL-BASED METHODS

Generation of large libraries of small molecules has required a reexamination of the methods chemists use to select their starting materials for synthesis. When a few reagents can be used to generate vast numbers of compounds, selection of an appropriately diverse set of starting materials is important. Since syntheses involve reactions between specific functional groups, it is reasonable to sort reagents by these groups. Then the diversity of the fragments attached to the given reactive functionality may be examined. This diversity may be defined in terms of the biologically relevant properties of a three-dimensional structure. Cell-based methodology can be used to divide reagents into convenient subsets from which representative diverse reagents can be selected for library synthesis. For ECLiPS libraries, analyses of the reagents used in each individual step have proven to be a useful strategy. Further cell-based analyses of the actual libraries in conjunction with biological activity data have shown cl...
Stags, Hawks, and Doves: Social Evolution Theory and Individual Variation in Cooperation

One of the triumphs of evolutionary biology is the discovery of robust mechanisms that promote the evolution of cooperative behaviors even when cooperation reduces the fertility or survival of cooperators. These mechanisms include, kin selection, reciprocity, and direct benefits to cooperation that are often nonlinear. Though they have been extensively studied separately, investigating the joint action of these mechanisms has been more difficult. Moreover, how these mechanisms shape variation in cooperation is not well known. Such variation is crucial for understanding the evolution of behavioral syndromes and animal personality. Here, I use the tools of kin selection and evolutionary game theory to build a framework that integrates these mechanisms for pairwise social interactions. Using relatedness as a measure of the strength of kin selection, responsiveness as a measure of reciprocity, and synergy as a measure of payoff nonlinearity, I show how different combinations of these three parameters produce directional selection for or against cooperation or variation in levels of cooperation via stabilizing or diversifying selection. Moreover, each of these outcomes maps uniquely to one of four classic games from evolutionary game theory, which means that modulating relatedness, responsiveness, and synergy effectively transforms the payoff matrix from one the evolutionary game to another. Assuming that cooperation exacts a fertility cost on cooperators and provides a fertility benefit to social partners, a prisoner's dilemma game and directional selection against cooperation occur when relatedness and responsiveness are low and synergy is not too positive. Enough positive synergy in these conditions generates a stag-hunt game and diversifying selection. High levels of relatedness or responsiveness turn cooperation from a fitness cost into a fitness benefit, which produces a mutualism game and directional selection for cooperation when synergy is not too negative. Sufficiently negative synergy in this case creates a hawk-dove game and stabilizing selection for cooperation. I extend the results with relatedness and synergy to social groups and show that how group size changes the effect of relatedness and synergy on selection for cooperation depends on how the per capita benefit of cooperation changes with group size. Together, these results provide a general framework with which to generate comparative predictions that can be tested using quantitative genetic techniques and experimental techniques that manipulate investment in cooperation. These predictions will help us understand both interspecific variation in cooperation as well as within-population and within-group variation in cooperation related to behavioral syndromes.
Oxazoles from β-acyloxy-N,N-bis (trimethylsilyl) enamines

Abstract Sequential addition of methyllithium and acyl chlorides to O-trimethylsilyl acetyltrimethylsilane cyanohydrin affords β-acyloxy-N,N-bis(trimethylsilyl)enamines which cyclize to 2-substituted-4,5-dimethyloxazoles under thermolysis or trimethylsilyl trifluoromethanesulfonate treatment.
Reaction Models For Supercritical Water Oxidation Processes

Quantitative models of the reaction kinetics are essential for the design and optimization of chemical processes wherein reactions occur. This paper provides an overview of research into the development of such models for supercritical water oxidation processes. We illustrate two different, but complementary approaches. One approach is empirical, and it is the traditional engineering kinetics approach. The second approach is fundamental, and it is based on the governing mechanism and elementary reaction steps. The advantages and disadvantages of the two approaches are also discussed.
Heterocellular Coupling Between Amacrine Cells and Ganglion Cells

All superclasses of retinal neurons, including bipolar cells (BCs), amacrine cells (ACs) and ganglion cells (GCs), display gap junctional coupling. However, coupling varies extensively by class. Heterocellular AC coupling is common in many mammalian GC classes. Yet, the topology and functions of coupling networks remains largely undefined. GCs are the least frequent superclass in the inner plexiform layer and the gap junctions mediating GC-to-AC coupling (GC::AC) are sparsely arrayed amidst large cohorts of homocellular AC::AC, BC::BC, GC::GC and heterocellular AC::BC gap junctions. Here, we report quantitative coupling for identified GCs in retinal connectome 1 (RC1), a high resolution (2 nm) transmission electron microscopy-based volume of rabbit retina. These reveal that most GC gap junctions in RC1 are suboptical. GC classes lack direct cross-class homocellular coupling with other GCs, despite opportunities via direct membrane contact, while OFF alpha GCs and transient ON directionally selective (DS) GCs are strongly coupled to distinct AC cohorts. Integrated small molecule immunocytochemistry identifies these as GABAergic ACs (γ+ ACs). Multi-hop synaptic queries of RC1 connectome further profile these coupled γ+ ACs. Notably, OFF alpha GCs couple to OFF γ+ ACs and transient ON DS GCs couple to ON γ+ ACs, including a large interstitial amacrine cell, revealing matched ON/OFF photic drive polarities within coupled networks. Furthermore, BC input to these γ+ ACs is tightly matched to the GCs with which they couple. Evaluation of the coupled versus inhibitory targets of the γ+ ACs reveals that in both ON and OFF coupled GC networks these ACs are presynaptic to GC classes that are different than the classes with which they couple. These heterocellular coupling patterns provide a potential mechanism for an excited GC to indirectly inhibit nearby GCs of different classes. Similarly, coupled γ+ ACs engaged in feedback networks can leverage the additional gain of BC synapses in shaping the signaling of downstream targets based on their own selective coupling with GCs. A consequence of coupling is intercellular fluxes of small molecules. GC::AC coupling involves primarily γ+ cells, likely resulting in GABA diffusion into GCs. Surveying GABA signatures in the GC layer across diverse species suggests the majority of vertebrate retinas engage in GC::γ+ AC coupling.
[P8Se18]6-: A New Oligomeric Selenophosphate Anion with P4+ and P3+ Centers and Pyramidal [PSe3] Fragments

The new oligomeric selenophosphate anion [P8Se18]6- has been prepared by stoichiometric reaction of K2Se, P, and Se at 510 °C. The molecule is an oligomeric unit, which consists of four [PyQz]n- su...
Control of microtubule dynamics using an optogenetic microtubule plus end–F-actin cross-linker

We developed a novel optogenetic tool, SxIP-improved light-inducible dimer (iLID), to facilitate the reversible recruitment of factors to microtubule (MT) plus ends in an end-binding protein-dependent manner using blue light. We show that SxIP-iLID can track MT plus ends and recruit tgRFP-SspB upon blue light activation. We used this system to investigate the effects of cross-linking MT plus ends and F-actin in Drosophila melanogaster S2 cells to gain insight into spectraplakin function and mechanism. We show that SxIP-iLID can be used to temporally recruit an F-actin binding domain to MT plus ends and cross-link the MT and F-actin networks. Cross-linking decreases MT growth velocities and generates a peripheral MT exclusion zone. SxIP-iLID facilitates the general recruitment of specific factors to MT plus ends with temporal control enabling researchers to systematically regulate MT plus end dynamics and probe MT plus end function in many biological processes.
Synthesis of 1-substituted [1,2,3]triazolo[4,5-d]pyridazines as precursors for novel tetraazapentalene derivatives

A series of 1-substituted 4,5-diformyl-[1,2,3]triazole derivatives were prepared by 1,3-dipolar cyclo-addition of aryl azides with acetylene dicarboxaldehyde mono-diethylacetal. The triazoles were readily converted into 1-substituted [1,2,3]triazolo[4,5-d]pyridazines in good yields. The 1-(2-nitrophenyl)-[1,2,3]triazolo[4,5-d]pyridazine was found to be a useful intermediate for the generation of the novel 5H-benzo[1,2,3]triazolo[1′,2′:1,2]triazolo[4,5-d]pyridazin-6-ium inner salt ring system.
Synthesis and Reactions of exo-Camphorylsulfonyloxaziridine

The first example of an exo-camphorylsulfonyloxaziridine 4a was prepared by m-CPBA oxidation of camphor imine 9. This surprising result is due to the conformation of the imine which apparently prevents attack of the peracid from the endo direction. Similar oxidations of all other camphorsulfonylimines result in the endo-oxaziridine exclusively. Asymmetric oxidation of sulfides to sulfoxides and the α-hydroxylation of enolates by 4 can be interpreted in terms of open transition states where nonbonded interactions are minimized. These results support earlier conclusions and predictions of the stereoselectivity and mechanisms of molecular recognition by the N-sulfonyloxaziridine class of oxidizing reagents.
Isolation and structure of five lyngbyabellin derivatives from a Papua New Guinea collection of the marine cyanobacterium Lyngbya majuscula

Abstract Five new lyngbyabellin analogs along with a known compound, dolabellin, have been isolated from the marine cyanobacterium Lyngbya majuscula collected from Papua New Guinea. The structures of lyngbyabellins E–I were elucidated through extensive spectroscopic analysis, including HR-FABMS and 1D and 2D NMR experiments. The absolute configurations of lyngbyabellin E and H were ascertained by chiral HPLC and GC/MS analysis of degradation products, in combination with NMR experiments. All five lyngbyabellins showed cytotoxicity to NCI-H460 human lung tumor and neuro-2a mouse neuroblastoma cell lines with LC 50 values between 0.2 and 4.8 μM.
Synthesis and antifolate activity of new pyrrolo[2,3-d]pyrimidine and thieno[2,3-d]pyrimidine inhibitors of dihydrofolate reductase

Three previously undescribed dihydrofolate reductase (DHFR) inhibitors, Nα-[4-[N-[(2,4-diaminopyrrolo[2,3-d]pyrimidin-5-yl)methyl]amino]benzoyl]-Nδ-hemiphthaloyl-L-ornithine (7), Nα- [4- [N-[(2,4-diaminothieno[2,3-d]pyrimidin-5-yl)methyl]amino]benzoyl]- Nδ-hemiphthaloyl-L-ornithine (8), and N-[4-[N-[(2,4-diaminothieno[2,3-d]pyrimidin-5-yl)methyl]amino]benzoyl]-L-glutamic acid (12), were synthesized and their antifolate activity was assessed. The ability of 7 and 8 to bind to DHFR and inhibit the growth of CCRF-CEM human lymphoblastic leukemia cells in culture were dramatically reduced in comparison with the corresponding pteridine analogue, Nα-(4-amino-4-deoxypteroyl)-Nδ-hemiphmaloyl-L-ornithine (1, PT523). In a similar manner, the antifolate activity of 12 was markedly reduced in comparison with that of the corresponding glutamate analogue, aminopterin (5, AMT). In contrast, 7, 8, and 12 all displayed excellent affinity for the reduced folate carrier (RFC) of CCRF-CEM cells as measured by a standard competitive influx assay. Lack of a consistent correlation between the results of the growth inhibition assays and those of the DHFR and RFC binding assays results suggest that additional factors also play a role in the antifolate activity of these compounds.
Thermal fluctuations of the unusually symmetric and stable superoxide tetrahydrate complex: An ab initio molecular dynamics study

We report an ab initio molecular dynamics simulation study of a complex composed of the superoxide anion and four water molecules. We probe the symmetry and stability of the superoxide tetrahydrate anion cluster at a low temperature (25 K) where there are vibrational spectra and a higher temperature (111 K) where experimental data are not available. From the ab initio simulation trajectory, we found the superoxide tetrahydrate complex to be highly symmetric, exhibiting a collective breathing motion on the picosecond time scale at low temperature that subsequently disappears at higher temperatures. Furthermore, we establish that superoxide tetrahydrate is a highly stable species at the higher temperature with little or no distortion to its geometry. The vibrational spectrum calculated from our ab initio trajectory is in reasonable agreement with experimental spectra, and we were able to assign individual peaks in the spectra to specific modes in the superoxide tetrahydrate anion cluster.
Oxazolidinone Protection of N-Acetylglucosamine Confers High Reactivity on the 4-Hydroxy Group in Glycosylation

[reaction: see text] The preparation of a convenient oxazolidinone protected N-acetyl glucosamine 4-OH derivative is reported. This substance exhibits enhanced reactivity as a glycosyl acceptor in a variety of coupling methods, the products of which are converted to the target N-acetylglucosaminyl saccharides under very mild conditions.
Solid Nitrogen at Extreme Conditions of High Pressure and Temperature

We review the phase diagram of nitrogen in a wide pressure and temperature range. Recent optical and x-ray diffraction studies at pressures up to 300 GPa and temperatures in excess of 1000 K have provided a wealth of information on the transformation of molecular nitrogen to a nonmolecular (polymeric) semiconducting and two new molecular phases. These newly found phases have very large stability (metastability) range. Moreover, two new molecular phases have considerably different orientational order from the previously known phases. In the iota phase (unlike most of other known molecular phases), N{sub 2} molecules are orientationally equivalent. The nitrogen molecules in the theta phase might be associated into larger aggregates, which is in line with theoretical predictions on polyatomic nitrogen.
Gas‐phase reactions of azulene with OH and NO3 radicals and O3 at 298 ± 2 K

Azulene, which is isomeric with naphthalene, was studied to determine whether it behaves like a polycyclic aromatic hydrocarbon or an alkene in its gas-phase reactions with OH and NO3 radicals and O3. Using relative rate methods, rate constants for the reactions of azulene with OH and NO3 radicals and O3 of (2.73 ± 0.56) × 10−10 cm3 molecule−1 s−1, (3.9) × 10−10 cm3 molecule−1 s−1, and <7 × 10−17 cm3 molecule−1 s−1, respectively, were obtained at 298 ± 2 K. The observation that the NO3 radical reaction did not involve NO2 in the rate determining step indicates that azulene behaves more like an alkene than a polycyclic aromatic hydrocarbon in this reaction. No conclusive evidence for the formation of nitroazulene(s) from either the OH or NO3 radical-initiated reaction of azulene (in the presence of NOx) was obtained.
Synthesis of trans-3,4-Dimethyl-4-(3-hydroxyphenyl)piperidine Opioid Antagonists: Application of the Cis-Thermal Elimination of Carbonates to Alkaloid Synthesis

Improved syntheses of twotrans-3,4-dimethyl-4-(3-hydroxyphenyl)piperidine opioid antagonists from 1,3-dimethyl-4-piperidinone are described. The 1,3-dimethyl-4-arylpiperidinol 23 was selectively dehydrated in a two step process to the 1,3-dimethyl-4-aryl-1,2,3,6-tetrahydropyridine 26 by the cis-thermal elimination of the corresponding alkyl carbonate derivative at 190 degrees C. In the presence of a basic nitrogen, the success of the elimination was found to be critically dependent upon the nature of the carbonate alkyl group, with Et, i-Bu, and i-Pr being preferred (90% yield). Alkylation of the metalloenamine, formed by deprotonation of 26 with n-BuLi, proceeded regio- and stereospecifically to give the trans-3,4-dimethyl-4-aryl-1,2,3,4-tetrahydropyridine 27, which was converted in three steps to the common intermediate, (3R,4R)-3,4-dimethyl-4-(3-hydroxyphenyl)piperidine. LY255582, a centrally-active opioid antagonist, and LY246736-dihydrate, a peripherally-active opioid antagonist, were prepared from 1,3-dimethyl-4-piperidinone in 11.8% yield (8 steps) and 6.2% yield (12 steps), respectively.
[2 + 2] Cycloaddition of Fullerenes with Electron-Rich Alkenes and Alkynes

Photochemical [2 + 2] cycloaddition of C60 with N,N-diethyl-4-methyl-3-penten-1-yn-1-amine (1) afforded the stable C60-fused cyclobutenamine 2 which underwent self-sensitized photooxidation to dihydrofullerenone amide 4 in high yield. Fullerenes C60 and C70 react thermally with tetraalkoxyethylenes to give dihydrofullerene cyclobutanediketals, which undergo a clean cycloreversion to fullerenes on irradiation with visible or UV light. Attempted hydrolysis of the ketals was unsuccessful, but treatment of 1,2-(6161,62,62-tetraethoxycyclobutano)dihydro[60]fullerene (8) with TMSI gave ring-contracted product 11 (by cleavage of the C−C bond to the fullerene fragment) along with reduction product 12.
EMHP: an accurate automated hole masking algorithm for single-particle cryo-EM image processing.

Summary The Electron Microscopy Hole Punch (EMHP) is a streamlined suite of tools for quick assessment, sorting and hole masking of electron micrographs. With recent advances in single-particle electron cryo-microscopy (cryo-EM) data processing allowing for the rapid determination of protein structures using a smaller computational footprint, we saw the need for a fast and simple tool for data pre-processing that could run independent of existing high-performance computing (HPC) infrastructures. EMHP provides a data preprocessing platform in a small package that requires minimal python dependencies to function. Availability and implementation https://www.bitbucket.org/chazbot/emhp Apache 2.0 License. Contact bowman@scripps.edu. Supplementary information Supplementary data are available at Bioinformatics online.
A Fast and Accurate Algorithm to Test for Binary Phenotypes and Its Application to PheWAS

The availability of electronic health record (EHR)-based phenotypes allows for genome-wide association analyses in thousands of traits and has great potential to enable identification of genetic variants associated with clinical phenotypes. We can interpret the phenome-wide association study (PheWAS) result for a single genetic variant by observing its association across a landscape of phenotypes. Because a PheWAS can test thousands of binary phenotypes, and most of them have unbalanced or often extremely unbalanced case-control ratios (1:10 or 1:600, respectively), existing methods cannot provide an accurate and scalable way to test for associations. Here, we propose a computationally fast score-test-based method that estimates the distribution of the test statistic by using the saddlepoint approximation. Our method is much (∼100 times) faster than the state-of-the-art Firth's test. It can also adjust for covariates and control type I error rates even when the case-control ratio is extremely unbalanced. Through application to PheWAS data from the Michigan Genomics Initiative, we show that the proposed method can control type I error rates while replicating previously known association signals even for traits with a very small number of cases and a large number of controls.
Comparison of the Cation Valence and Coordination in Ce2UO6 and Ce2MoO6

Ce2UO6 and Ce2MoO6 have both been suggested to have significant charge transfer between the metal ions. To quantify this proposed charge transfer, the valence and coordination of cerium and uranium in Ce2UO6 as well as cerium and molybdenum in Ce2MoO6 were studied through a combination of K-, L-, and M-edge XAFS (X-ray absorption fine structure). The results clearly show that these two compounds are not isostructural. Whereas Ce and U in Ce2UO6 are found to disorder on a single site, consistent with the formation of the solid solution Ce0.67U0.33O2, the Ce and Mo coordination is very different. The Mo sits on a site with tetrahedral coordination. The XANES (X-ray absorption near edge structure) data show that for Ce2UO6, Ce and U are both tetravalent, whereas for Ce2MoO6, Ce is trivalent and Mo is hexavalent. There is no evidence in either compound for any significant charge transfer or intermediate valence. The unusual physical properties exhibited by these materials are discussed in light of these findings.
ORBIT: a New Paradigm for Genetic Engineering of Mycobacterial Chromosomes.

ABSTRACT Two efficient recombination systems were combined to produce a versatile method for chromosomal engineering that obviates the need to prepare double-stranded DNA (dsDNA) recombination substrates. A synthetic “targeting oligonucleotide” is incorporated into the chromosome via homologous recombination mediated by the phage Che9c RecT annealase. This oligonucleotide contains a site-specific recombination site for the directional Bxb1 integrase (Int), which allows the simultaneous integration of a “payload plasmid” that contains a cognate recombination site and a selectable marker. The targeting oligonucleotide and payload plasmid are cotransformed into a RecT- and Int-expressing strain, and drug-resistant homologous recombinants are selected in a single step. A library of reusable target-independent payload plasmids is available to generate gene knockouts, promoter replacements, or C-terminal tags. This new system is called ORBIT (for “oligonucleotide-mediated recombineering followed by Bxb1 integrase targeting”) and is ideally suited for the creation of libraries consisting of large numbers of deletions, insertions, or fusions in a bacterial chromosome. We demonstrate the utility of this “drag and drop” strategy by the construction of insertions or deletions in over 100 genes in Mycobacterium tuberculosis and M. smegmatis. IMPORTANCE We sought to develop a system that could increase the usefulness of oligonucleotide-mediated recombineering of bacterial chromosomes by expanding the types of modifications generated by an oligonucleotide (i.e., insertions and deletions) and by making recombinant formation a selectable event. This paper describes such a system for use in M. smegmatis and M. tuberculosis. By incorporating a single-stranded DNA (ssDNA) version of the phage Bxb1 attP site into the oligonucleotide and coelectroporating it with a nonreplicative plasmid that carries an attB site and a drug selection marker, we show both formation of a chromosomal attP site and integration of the plasmid in a single transformation. No target-specific dsDNA substrates are required. This system will allow investigators studying mycobacterial diseases, including tuberculosis, to easily generate multiple mutants for analysis of virulence factors, identification of new drug targets, and development of new vaccines.
Enhanced X-ray emission from candidate Lyman continuum emitting galaxies

X-ray binaries may have helped reionize the early Universe by enabling Lyman continuum escape. We analyzed a set of 8 local galaxies that are potential Lyman leaking galaxies, identified by a blue color and weak emission lines, using Chandra X-ray observations. Five of the galaxies feature X-ray sources, while three galaxies are not significantly detected in X-rays. X-ray luminosities were found for the galaxies and X-ray sources. Four of the galaxies have elevated X-ray luminosity versus what would be expected based on star formation rate and metallicity. The presence of detected X-ray sources within the galaxies is found to correlate with the ratio of the star formation rate estimated from the near-ultraviolet flux to that estimated from the infrared. This implies reduced obscuration due to dust in the galaxies with X-ray sources. These results support the idea that X-ray binaries may be an important part of the process of reionziation.
Generation of structural diversity in polyphosphazenes

Polyphosphazenes are macromolecules with a chain of alternating phosphorus and nitrogen atoms and with two (usually) organic side groups linked to each phosphorus. Although the earliest poly(organophosphazenes) were essentially linear polymers each bearing only one type of side group along the chain, research in our program in recent years has widened the scope to include mixed-substituent polymers with two or more different side groups, block copolymers, comb structures, stars, and dendrimers, all with a wide variety of different properties. In addition, supramolecular systems have also been synthesized including vesicles, microspheres, and a variety of composite systems. This review provides a summary of these developments together with an introduction to the widening array of developing uses. Copyright © 2013 John Wiley & Sons, Ltd.
Recent Advances in the Catalytic Syntheses of Allenes: A Critical Assessment

The increasing synthetic utility of allenes in organic synthesis combined with their incorporation into a growing list of natural products and active pharmaceutical ingredients has stimulated an intense effort recently to identify efficient catalytic methods for their synthesis. In addition, as the only common functional group in organic chemistry that possesses axial chirality, efforts to discover new asymmetric catalysts for the enantioselective synthesis of axially chiral allenes has intensified as these substrates become more ubiquitous as chiral building blocks for downstream asymmetric methodologies. Nonetheless, despite this intensive effort, the ability to access racemic or chiral allenes from readily available starting materials using catalytic processes has yet to meet the demand of their expanding applications. The focus of this Perspective is to provide a critical assessment on the most recent developments in the field of catalytic syntheses of allenes (2011–2013) highlighting both the advanta...
SYNTHESIS AND CHARACTERIZATION OF TWO NEW TELLUROINDATES : K6IN2TE6.4C2H8N2 AND (PH4P)2IN2TE6

Solventothermal reaction of certain binary alloys and quaternary alloys with tetraalkylammonium salts in ethylenediamine yielded K6In2Te6·4C2H8N2 and (Ph4P)2In2Te6, respectively. A highly charged d...
A diastereoselective tandem metalloenamine alkylation/aza-annulation of β-tetralones expedites the synthesis of benzoquinolinones

Abstract In one operation, metalloenamines derived from R -phenylethylamine (PEA) and a β-tetralone were treated with an electrophile followed by acrylic anhydride. The unpurified lactams were reduced to give 10b-angular benzoquinolinones (BQs).
Parallel visual circuitry in a basal chordate

A common CNS architecture is observed in all chordates, from vertebrates to basal chordates like the ascidian Ciona. Ciona stands apart among chordates in having a complete larval connectome. Starting with visuomotor circuits predicted by the Ciona connectome, we used expression maps of neurotransmitter use with behavioral assays to identify two parallel visuomotor circuits that are responsive to different components of visual stimuli. The first circuit is characterized by glutamatergic photoreceptors and responds to the direction of light. These photoreceptors project to cholinergic motor neurons, via two tiers of cholinergic interneurons. The second circuit responds to changes in ambient light and mediates an escape response. This circuit uses GABAergic photoreceptors which project to GABAergic interneurons, and then to cholinergic interneurons. Our observations on the behavior of larvae either treated with a GABA receptor antagonist or carrying a mutation that eliminates photoreceptors indicate the second circuit is disinhibitory.
Bargaining and conflict with up-front investments: How power asymmetries matter

Abstract We examine settings—such as litigation, labor relations, or arming and war—in which players first make non-contractible up-front investments to improve their bargaining position and gain advantage for possible future conflict. Bargaining is efficient ex post, but we show that a player may prefer Conflict ex ante if there are sufficient asymmetries in strength. There are two sources of this finding. First, up-front investments are more dissimilar between players under Conflict, and they are lower than under Bargaining when one player is much stronger than the other. Second, the probability of the stronger player winning in Conflict is higher than the share received under Nash bargaining. We thus provide a rationale for conflict to occur under complete information that does not depend on long-term commitment problems. Greater balance in institutional support for different sides is more likely to maintain peace and settlements.
Electrophysiology and transcriptomics reveal two photoreceptor classes and complex visual integration in Hirudo verbana

Among animals with visual processing mechanisms, the leech Hirudo verbana is a rare example in which all neurons can be identified. However, little is known about its visual system, which is composed of several pigmented head eyes and photosensitive non-pigmented sensilla that are distributed across its entire body. Although several interneurons are known to respond to visual stimuli, their response properties are poorly understood. Among these, the S-cell system is especially intriguing: it is multimodal, spans the entire body of the leech and is thought to be involved in sensory integration. To improve our understanding of the role of this system, we tested its spectral sensitivity, spatial integration and adaptation properties. The response of the S-cell system to visual stimuli was found to be strongly dependent on the size of the area stimulated, and adaptation was local. Furthermore, an adaptation experiment demonstrated that at least two color channels contributed to the response, and that their contribution was dependent on the adaptation to the background. The existence of at least two color channels was further supported by transcriptomic evidence, which indicated the existence of at least two distinct groups of putative opsins for leeches. Taken together, our results show that the S-cell system has response properties that could be involved in the processing of spatial and color information of visual stimuli. We propose the leech as a novel system to understand visual processing mechanisms with many practical advantages.
Sciunits: Reusable Research Objects

Science is conducted collaboratively, often requiring knowledge sharing about computational experiments. When experiments include only datasets, they can be shared using Uniform Resource Identifiers (URIs) or Digital Object Identifiers (DOIs). An experiment, however, seldom includes only datasets, but more often includes software, its past execution, provenance, and associated documentation. The Research Object has recently emerged as a comprehensive and systematic method for aggregation and identification of diverse elements of computational experiments. While a necessary method, mere aggregation is not sufficient for the sharing of computational experiments. Other users must be able to easily recompute on these shared research objects. In this paper, we present the sciunit, a reusable research object in which aggregated content is recomputable. We describe a Git-like client that efficiently creates, stores, and repeats sciunits. We show through analysis that sciunits repeat computational experiments with minimal storage and processing overhead. Finally, we provide an overview of sharing and reproducible cyberinfrastructure based on sciunits gaining adoption in the domain of geosciences.
An Application of the Generalization of Ceva's Theorem

Theorem: Let us consider a polygon A1A2...An inserted in a circle. Let s and t be two non zero natural numbers such that 2s+t = n . By each vertex Ai passes a line di which intersects the lines Ai + sAi+s+1,....,Ai+s+t −1Ai+s+t at the points Mi,i+s,..., Mi+ s+t−1 respectively and the circle at the point Mi'.
Handling class imbalance in link prediction using learning to rank techniques

We consider the link prediction (LP) problem in a partially observed network, where the objective is to make predictions in the unobserved portion of the network. Many existing methods reduce LP to binary classification. However, the dominance of absent links in real world networks makes misclassification error a poor performance metric. Instead, researchers have argued for using ranking performance measures, like AUC, AP and NDCG, for evaluation. We recast the LP problem as a learning to rank problem and use effective learning to rank techniques directly during training which allows us to deal with the class imbalance problem systematically. As a demonstration of our general approach, we develop an LP method by optimizing the cross-entropy surrogate, originally used in the popular ListNet ranking algorithm. We conduct extensive experiments on publicly available co-authorship, citation and metabolic networks to demonstrate the merits of our method.
Log-scale equidistribution of nodal sets in Grauert tubes

Abstract Let M τ 0 be the Grauert tube (of some fixed radius τ 0 ) of a compact, negatively curved, real analytic Riemannian manifold M without boundary. Let φ λ be a Laplacian eigenfunction on M of eigenvalue − λ 2 and let φ λ C be its holomorphic extension to M τ 0 . In this article, we prove that on M τ 0 ∖ M , there exists a dimensional constant α > 0 and a full density subsequence { λ j k } k = 1 ∞ of the spectrum for which the masses of the complexified eigenfunctions φ λ j k C are asymptotically equidistributed at length scale ( log ⁡ λ j k ) − α . Moreover, the complex zeros of φ λ j k C also become equidistributed on this logarithmic length scale.
A canonical linear system associated to adjoint divisors in characteristic $p > 0$

Suppose that X is a projective variety over an algebraically closed field of characteristic p > 0. Further suppose that L is an ample (or more generally in some sense positive) divisor. We study a natural linear system in H 0 (X,OX(KX + L)). We further generalize this to incorporate a boundary divisor �. We show that these subsystems behave like the global sections associated to multiplier ideals, H 0 (X,J(X,�)L) in characteristic zero. In particular, we show that these systems are in many cases base-point-free. While the original proof utilized Kawamata-Viehweg vanishing and variants of multiplier ideals, our proof uses test ideals.
Dynamic Connectivity Game for Adversarial Internet of Battlefield Things Systems

In this paper, the problem of network connectivity is studied for an adversarial Internet of Battlefield Things (IoBT) system in which an attacker aims at disrupting the connectivity of the network by choosing to compromise one of the IoBT nodes at each time epoch. To counter such attacks, an IoBT defender attempts to reestablish the IoBT connectivity by either deploying new IoBT nodes or by changing the roles of existing nodes. This problem is formulated as a dynamic multistage Stackelberg connectivity game that extends classical connectivity games and that explicitly takes into account the characteristics and requirements of the IoBT network. In particular, the defender’s payoff captures the IoBT latency as well as the sum of weights of disconnected nodes at each stage of the game. Due to the dependence of the attacker’s and defender’s actions at each stage of the game on the network state, the feedback Stackelberg solution [feedback Stackelberg equilibrium (FSE)] is used to solve the IoBT connectivity game. Then, sufficient conditions under which the IoBT system will remain connected, when the FSE solution is used, are determined analytically. Numerical results show that the expected number of disconnected sensors, when the FSE solution is used, decreases up to 46% compared to a baseline scenario in which a Stackelberg game with no feedback is used, and up to 43% compared to a baseline equal probability policy.
Obladi: oblivious serializable transactions in the cloud

This paper presents the design and implementation of Obladi, the first system to provide ACID transactions while also hiding access patterns. Obladi uses as its building block oblivious RAM, but turns the demands of supporting transactions into a performance opportunity. By executing transactions within epochs and delaying commit decisions until an epoch ends, Obladi reduces the amortized bandwidth costs of oblivious storage and increases overall system throughput. These performance gains, combined with new oblivious mechanisms for concurrency control and recovery, allow Obladi to execute OLTP workloads with reasonable throughput: it comes within 5× to 12× of a non-oblivious baseline on the TPC-C, SmallBank, and FreeHealth applications. Latency overheads, however, are higher (70× on TPC-C).
Accessing Defect Dynamics using Intense, Nanosecond Pulsed Ion Beams

Gaining in-situ access to relaxation dynamics of radiation induced defects will lead to a better understanding of materials and is important for the verification of theoretical models and simulations. We show preliminary results from experiments at the new Neutralized Drift Compression Experiment (NDCX-II) at Lawrence Berkeley National Laboratory that will enable in-situ access to defect dynamics through pump-probe experiments. Here, the unique capabilities of the NDCX-II accelerator to generate intense, nanosecond pulsed ion beams are utilized. Preliminary data of channeling experiments using lithium and potassium ions and silicon membranes are shown. We compare these data to simulation results using Crystal Trim. Furthermore, we discuss the improvements to the accelerator to higher performance levels and the new diagnostics tools that are being incorporated.
Local Differential Privacy for Evolving Data

There are now several large scale deployments of differential privacy used to collect statistical information about users. However, these deployments periodically recollect the data and recompute the statistics using algorithms designed for a single use. As a result, these systems do not provide meaningful privacy guarantees over long time scales. Moreover, existing techniques to mitigate this effect do not apply in the ``local model'' of differential privacy that these systems use. In this paper, we introduce a new technique for local differential privacy that makes it possible to maintain up-to-date statistics over time, with privacy guarantees that degrade only in the number of changes in the underlying distribution rather than the number of collection periods. We use our technique for tracking a changing statistic in the setting where users are partitioned into an unknown collection of groups, and at every time period each user draws a single bit from a common (but changing) group-specific distribution. We also provide an application to frequency and heavy-hitter estimation.
Polynomial-Time Tensor Decompositions with Sum-of-Squares

We give new algorithms based on the sum-of-squares method for tensor decomposition. Our results improve the best known running times from quasi-polynomial to polynomial for several problems, including decomposing random overcomplete 3-tensors and learning overcomplete dictionaries with constant relative sparsity. We also give the first robust analysis for decomposing overcomplete 4-tensors in the smoothed analysis model. A key ingredient of our analysis is to establish small spectral gaps in moment matrices derived from solutions to sum-of-squares relaxations. To enable this analysis we augment sum-of-squaresrelaxations with spectral analogs of maximum entropy constraints.
Topologically slice knots with nontrivial Alexander polynomial

Abstract Let C T be the subgroup of the smooth knot concordance group generated by topologically slice knots and let C Δ be the subgroup generated by knots with trivial Alexander polynomial. We prove that C T / C Δ is infinitely generated. Our methods reveal a similar structure in the 3-dimensional rational spin bordism group, and lead to the construction of links that are topologically, but not smoothly, concordant to boundary links.
Node isolation of secure wireless sensor networks under a heterogeneous channel model

We investigate the secure connectivity of wireless sensor networks under a heterogeneous random key predistribution scheme and a heterogeneous channel model. In particular, we study a random graph formed by the intersection of an inhomogeneous random key graph with an inhomogeneous Erdős-Renyi graph. The former graph is naturally induced by the heterogeneous random key predistribution scheme while the latter graph constitutes a heterogeneous on/off channel model; wherein, the wireless channel between a class-i node and a class-j node is on with probability α ij independently. We present conditions (in the form of zero-one laws) on how to scale the parameters of the intersection model so that it has no isolated node with high probability as the number of nodes gets large. We also present numerical results to support these zero-one laws in the finite-node regime.
Neutron Electric Dipole Moments from Beyond the Standard Model Physics

Neutron Electric Dipole Moment (nEDM), a generic feature of CP-violation, is predicted to be very small in the Standard Model, but can be much larger in most extensions of the model. In this talk, I will discuss the classification of the CP violating operators up to dimension 6 that can give rise to nEDM, and then describe the mixing and renormalization structure of the operators of dimension 5 and lower in both dimensional and cutoff regularizations in general terms. Finally I will describe how to connect the dimension 5 operators, in particular, the Chromoelectric Dipole Moment of the quarks, between MSbar scheme and a Regularization Independent prescription in the chiral limit.
Finding Exogenous Variation in Data

We reconsider the classic problem of recovering exogenous variation from an endogenous regressor. Two-stage least squares recovers exogenous variation through presuming the existence of an instrumental variable. We rely instead on the assumption that the regressor is a mixture of exogenous and endogenous observations--say as the result of temporary natural experiments. With this assumption, we propose an alternative two-stage method based on nonparametrically estimating a mixture model to recover a subset of the exogenous observations. We demonstrate that our method recovers exogenous observations in simulation and can be used to find pricing experiments hidden in grocery store scanner data.
A note on automatic data transformation

Modern data analysis frequently involves variables with highly non-Gaussian marginal distributions. However, commonly used analysis methods are most effective with roughly Gaussian data. This paper introduces an automatic transformation that improves the closeness of distributions to normality. For each variable, a new family of parametrizations of the shifted logarithm transformation is proposed, which is unique in treating the data as real valued and in allowing transformation for both left and right skewness within the single family. This also allows an automatic selection of the parameter value (which is crucial for high-dimensional data with many variables to transform) by minimizing the Anderson–Darling test statistic of the transformed data. An application to image features extracted from melanoma microscopy slides demonstrates the utility of the proposed transformation in addressing data with excessive skewness, heteroscedasticity and influential observations. Copyright © 2016 John Wiley & Sons, Ltd.