cssi/SciSciGPT-SciSciNet huggingface dataset:
The C-Terminal Domain of RNA Polymerase II Is a Multivalent Targeting Sequence that Supports Drosophila Development with Only Consensus Heptads.

Summary The C-terminal domain (CTD) of RNA polymerase II (Pol II) is composed of repeats of the consensus YSPTSPS and is an essential binding scaffold for transcription-associated factors. Metazoan CTDs have well-conserved lengths and sequence compositions arising from the evolution of divergent motifs, features thought to be essential for development. On the contrary, we show that a truncated CTD composed solely of YSPTSPS repeats supports Drosophila viability but that a CTD with enough YSPTSPS repeats to match the length of the wild-type Drosophila CTD is defective. Furthermore, a fluorescently tagged CTD lacking the rest of Pol II dynamically enters transcription compartments, indicating that the CTD functions as a signal sequence. However, CTDs with too many YSPTSPS repeats are more prone to localize to static nuclear foci separate from the chromosomes. We propose that the sequence complexity of the CTD offsets aberrant behavior caused by excessive repetitive sequences without compromising its targeting function.
Distributional reinforcement learning with linear function approximation

Despite many algorithmic advances, our theoretical understanding of practical distributional reinforcement learning methods remains limited. One exception is Rowland et al. (2018)'s analysis of the C51 algorithm in terms of the Cramer distance, but their results only apply to the tabular setting and ignore C51's use of a softmax to produce normalized distributions. In this paper we adapt the Cramer distance to deal with arbitrary vectors. From it we derive a new distributional algorithm which is fully Cramer-based and can be combined to linear function approximation, with formal guarantees in the context of policy evaluation. In allowing the model's prediction to be any real vector, we lose the probabilistic interpretation behind the method, but otherwise maintain the appealing properties of distributional approaches. To the best of our knowledge, ours is the first proof of convergence of a distributional algorithm combined with function approximation. Perhaps surprisingly, our results provide evidence that Cramer-based distributional methods may perform worse than directly approximating the value function.
Bias from Survival in Prevalent Case–Control Studies †

Odds ratios comparing prevalent cases with controls may be biased if the exposures of interest affect the survival of incident cases. Keywords: prevalent case; case–control study; bias
When Do Municipal Consolidations Reduce Government Expenditures? Evidence on the Role of Local Involvement

Higher levels of government motivate municipal consolidations as a tool to increase efficiency in the local government sector, yet research shows consolidations typically fail to deliver the promised spending reductions. Since mergers often require significant changes to institutional structures, one potential explanation is that local decision makers can substantially influence the outcomes of the consolidations process. To explore this possibility, this paper contrasts “encouraged but voluntary” mergers with those that were “forced” on local governments in the state of New South Wales, Australia. Results show voluntary mergers resulted in a ten percent decline in total per capita expenditures, but forced consolidations failed to reduce spending across the board. The policy conclusion is decision makers considering structural reform should invest in obtaining the support and participation of local government decision makers.
Information Correlated Lévy Walk Exploration and Distributed Mapping Using a Swarm of Robots

In this article, we present a novel distributed method for constructing an occupancy grid map of an unknown environment using a swarm of robots with global localization capabilities and limited interrobot communication. The robots explore the domain by performing Levy walks in which their headings are defined by maximizing the mutual information between the robot's estimate of its environment in the form of an occupancy grid map and the distance measurements that it is likely to obtain when it moves in that direction. Each robot is equipped with laser range sensors, and it builds its occupancy grid map by repeatedly combining its own distance measurements with map information that is broadcast by neighboring robots. Using results on average consensus over time-varying graph topologies, we prove that all robots’ maps will eventually converge to the actual map of the environment. In addition, we demonstrate that a technique based on topological data analysis, developed in our previous work for generating topological maps, can be readily extended for adaptive thresholding of occupancy grid maps. We validate the effectiveness of our distributed exploration and mapping strategy through a series of two-dimensional simulations and multirobot experiments.
The impact of mask topography on binary reticles at the 65nm node

Most lithography simulation software, such as OPC decoration engines, employ the thin-mask approximation for imaging calculations. While it is well known that a more rigorous approach is often needed for alternating phase-shift reticles, a solution to the full Maxwell equations is rarely used for binary masks. In the past, both the patterns and the thickness of the patterns for COG and attenuated PSM were relatively small compared with the illuminating wavelength. For the future technology nodes, this will not be true. For example, scattering bars are typically a quarter to a third of the size of the main feature. This means that a 65nm isolated line with typically have 65nm to 85nm assist features (mask scale). We have found a non-constant bias through pitch for low k1 imaging that is not found with the thin-mask approach. Results are presented for varying feature sizes, chrome thickness, and for both lines and spaces.
The mechanisms and meteorological drivers of the ozone–temperature relationship

Abstract. Surface ozone (O3) pollution levels are strongly correlated with daytime surface temperatures, especially in highly polluted regions. This correlation is nonlinear and occurs through a variety of temperature dependent mechanisms related to O3 precursor emissions, lifetimes, and reaction rates, making the reproduction of temperature sensitivities – and the projection of associated human health risks – a complex problem. Here we explore the summertime O3–temperature relationship in the United States and Europe using the chemical transport model GEOS-Chem. We remove the temperature dependence of several mechanisms most frequently cited as causes of the O3–temperature climate penalty , including: PAN decomposition, soil NOx emissions, biogenic VOC emissions, and dry deposition. We quantify the contribution of each mechanism to the overall correlation between O3 and temperature both individually and collectively. Through this analysis we find that the thermal decomposition of PAN can explain, on average, 20 % of the overall O3–temperature correlation in the United States. The effect is weaker in Europe, explaining 9 % of the overall O3–temperature relationship. The temperature dependence of biogenic emissions contributes 3 % and 9 % of the total O3–temperature correlation in the United States and Europe on average, while temperature dependent deposition (6 % and 1 %) and soil NOx emissions (10 % and 7 %) also contribute. Even considered collectively these mechanisms explain less than 46 % of the modeled O3–temperature correlation in the United States and 36 % in Europe. We use commonality analysis to demonstrate that covariance with other meteorological phenomena such as stagnancy and humidity can explain the bulk of the remainder of the O3–temperature correlation. Thus, we demonstrate that the statistical correlation between O3 and temperature alone may greatly overestimate the direct impacts of temperature on O3, with implications for the interpretation of policy-relevant metrics such as climate penalty .
Construction of Carbocyclic Arrays Containing Nitrogen via Intramolecular Imino Diels−Alder Reactions in Polar Media. A Comparative Study: 5.0 M Lithium Perchlorate−Diethyl Ether versus Water

The intramolecular Diels−Alder reaction of iminium ions has been examined in polar media such as 5.0 M lithium perchlorate−diethyl ether and water. Cycloaddition of 3 in 5.0 M lithium perchlorate−diethyl ether containing 10 mol % camphorsulfonic acid proceeds, not by in situ generation of iminium ion 1, but rather via N-(acyloxy)iminium ion 7 which subsequently cyclizes to tricyclic compounds 4 and 5. Direct formation of imines 15 and 30 was realized by reduction of the corresponding lactams (13 and 29, respectively) followed by exposure to 2.0 equiv of tetra-n-butylammonium fluoride. Exposure of the trifluoroacetic acid salt 18 of imine 15 to 5.0 M lithium perchlorate−diethyl ether at ambient temperature gave rise to tricyclic amine 16 in which the diene underwent isomerization prior to [4+2] cycloaddition. In contrast, use of water provided tricyclic amine 19. Similarly, exposure of iminium salt 31 to water afforded tricyclic amine 32. The polar sovent of choice for intramolecular imino Diels−Alder reac...
Mechanistic Study of LiNH2BH3 Formation from (LiH)4 + NH3BH3 and Subsequent Dehydrogenation

The formation of LiNH2BH3 from (LiH)4 and NH3BH3 and the subsequent dehydrogenation have been studied computationally at the CCSD(T)/6-311++G(3d,2p)//MP2/6-311++G(2d,p) level. A cubic unit of (LiH)4 is predicted to react readily with NH3BH3 to form LiNH2BH3 plus H2. The (LiH)4 tetramer enables dehydrogenation through the exchange of a hydride vertex of (LiH)4 and NH2BH3− where NH2BH3− is formed when the hydride vertex of (LiH)4 abstracts a proton from NH3. The free energy of activation for loss of H2 is reduced from 37.2 kcal/mol in NH3BH3 to 11.0 kcal/mol in (LiH)4 + NH3BH3. Further, H2 elimination from the (LiNH2BH3)2 dimer is predicted to be much easier than from the monomer which may suggest a cooperative H2-loss mechanism is possible in solid LiNH2BH3. While two molecules of H2 can be lost reversibly from (LiNH2BH3)2, loss of further H2 molecules is more difficult but could occur if the lattice energy stabilization accompanying H2 loss is sufficiently large.
Preparation and Fluorescence Spectroscopy of Bulk Monoclinic Eu3+:Y2O3 and Comparison to Eu3+:Y2O3 Nanocrystals

We report the laser spectroscopic characterization of bulk monoclinic Eu3+:Y2O3, which was prepared by a high-temperature, high-pressure synthesis method. The bulk monoclinic phase has sharp spectral lines without the line broadening and “secondary phase” of Eu3+:Y2O3 nanocrystals. The unusual optical properties of site A in this material have been determined to be intrinsic to the monoclinic phase and are not a result of surface effects in the nanocrystals. The 5D0 fluorescence lifetimes are longer in the nanocrystals than in the bulk material, indicating that there is no lifetime shortening in the nanocrystals due to quenching by the proximity of surface defects.
Theoretical Study on the Thermochemistry of Chlorinated and Fluorinated Germanes and Their Radical Fragments

The structures, vibrational frequencies, enthalpies of formation, and dissociation energies of germane, chlorinated and fluorinated germanes, and their radical fragments have been examined with density functional theory and quantum chemistry ab initio methods. The theoretical vibrational frequencies of the germanes at the B3LYP/6-31G(2df,p) level are in good agreement with the experimental data, but those of the germyl radicals largely disagree with the previous experimental assignments. The G3//DFT enthalpies of formation of GeH 4 , GeCl 4 , and GeCl 2 are within two times of the experimental uncertainties, while that of GeF 4 differs with the experiment by ∼10 kJ/mol. The calculated enthalpies of formation of the Ge-containing radicals have a large discrepancy with the available experimental data (which have large uncertainties). The bond dissociation energies of the Ge species and their trends with the F/Cl substitutions are evaluated at the G3 level as well. For dissociation of partially substituted F/Cl-germanes and germyl radicals, a propensity of diatomic elimination of H 2 or HF/HCl over single bond breaking is suggested, based on the low-energy barriers of the diatomic eliminations relative to the bond breakage to form Ge-containing radicals.
Phylofactorization: a graph partitioning algorithm to identify phylogenetic scales of ecological data

The problem of pattern and scale is a central challenge in ecology (sensu Levin, 1992). The problem of scale is central to community ecology, where functional ecological groups are aggregated and treated as a unit underlying an ecological pattern, such as aggregation of nitrogen fixing trees into a total abundance of a trait underlying ecosystem physiology. With the emergence of massive community ecological datasets, from microbiomes to breeding bird surveys, there is a need to objectively identify the scales of organization pertaining to well-defined patterns in community ecological data. The phylogeny is a scaffold for identifying key phylogenetic scales associated with macroscopic patterns. Phylofactorization was developed to objectively identify phylogenetic scales underlying patterns in relative abundance data. However, many ecological data, such as presence-absences and counts, are not relative abundances, yet the logic of defining phylogenetic scales underlying a pattern of interest is still applicable. Here, we generalize phylofactorization beyond relative abundances to a graph-partitioning algorithm for traits and community-ecological data from any exponential-family distribution. Generalizing phylofactorization yields many tools for analyzing community ecological data. In the context of generalized phylofactorization, we identify three phylogenetic factors of mammalian body mass which arose during the K-Pg extinction event, consistent with other analyses of mammalian body mass evolution. We introduce a phylogenetic analysis of variance which refines our understanding of the major sources of variation in the human gut. We employ generalized additive modeling of microbes in central park soils to confirm that a large clade of Acidobacteria thrive in neutral soils. We demonstrate how to extend phylofactorization to generalized linear and additive modeling of any dataset of exponential family random variables. We finish with a discussion of how phylofactorization produces a novel species concept, a hybrid of a phylogenetic and ecological species concepts in which the phylogenetic scales and units of interest are defined objectively by defining the ecological pattern and partitioning the phylogeny into clades based on different contributions to the pattern. All of these tools can be implemented with a new R package available online.
Population genomics of Wolbachia and mtDNA in Drosophila simulans from California

Wolbachia pipientis is an intracellular endosymbiont infecting many arthropods and filarial nematodes. Little is known about the short-term evolution of Wolbachia or its interaction with its host. Wolbachia is maternally inherited, resulting in co-inheritance of mitochondrial organelles such as mtDNA. Here I explore the evolution of Wolbachia, and the relationship between Wolbachia and mtDNA, using a large inbred panel of Drosophila simulans. I compare this to the only other large population genomic Wolbachia dataset from D. melanogaster. I find reduced diversity relative to expectation in both Wolbachia and mtDNA, but only mtDNA shows evidence of a recent selective sweep or population bottleneck. I estimate Wolbachia and mtDNA titre in each genotype, and I find considerable variation in both phenotypes, despite low genetic diversity in Wolbachia and mtDNA. A phylogeny of Wolbachia and of mtDNA suggest a recent origin of the infection derived from a single origin. Using Wolbachia and mtDNA titre as a phenotype, I perform the first association analysis using this phenotype with the nuclear genome and find several implicated regions, including one which contains four CAAX-box protein processing genes. CAAX-box protein processing can be an important part of host-pathogen interactions in other systems, suggesting interesting directions for future research.
Remarkable Diastereoselectivity in the Addition of Allylic and Unsaturated Diorganozinc Reagents to β-(N,N-Dialkylamino)-aldehydes

1,3-Anti amino alcohols 5a−18a are obtained with high diastereoselectivity by use of diorganozinc reagents in additions to amino aldehydes 2a and 2b. The corresponding Grignard reagents exhibit low to modest diastereoselectivity. The highly diastereoselective zinc-based method makes available a wide range of 4,4-disubstituted cyclohexenone derivatives containing contiguous stereocenters.
Spatial control of neuronal metabolism through glucose-mediated mitochondrial transport regulation

Eukaryotic cells modulate their metabolism by organizing metabolic components in response to varying nutrient availability and energy demands. In rat axons, mitochondria respond to glucose levels by halting active transport in high glucose regions. We employ quantitative modeling to explore physical limits on spatial organization of mitochondria and localized metabolic enhancement through regulated stopping of processive motion. We delineate the role of key parameters, including cellular glucose uptake and consumption rates, that are expected to modulate mitochondrial distribution and metabolic response in spatially varying glucose conditions. Our estimates indicate that physiological brain glucose levels fall within the limited range necessary for metabolic enhancement. Hence mitochondrial localization is shown to be a plausible regulatory mechanism for neuronal metabolic flexibility in the presence of spatially heterogeneous glucose, as may occur in long processes of projection neurons. These findings provide a framework for the control of cellular bioenergetics through organelle trafficking.
Reaction of ClONO2 with H2O and HCl in Sulfuric Acid and HNO3/H2SO4/H2O Mixtures

Measurements of the reaction probabilities (γ) for ClONO2 onto sulfuric acid solutions at 200−270 K are described. ClONO2 uptake due to reaction with H2O and with HCl in H2SO4 solutions (45−55 wt %) was investigated at 203−205 K. ClONO2 hydrolysis was also investigated on 36.5, 40, and 75 wt % sulfuric acid solutions over a range of temperatures. The measured γ are generally in good agreement with previously reported values. In addition, the solubility of HCl was determined for 45 and 50 wt % sulfuric acid from 200 to 225 K. The uptake of ClONO2 onto small sulfuric acid particles was studied resulting in a lower limit to the sticking coefficient of 0.5. ClONO2 reaction probabilities were also measured on H2SO4 solutions containing significant amounts of HNO3. In opposition to previous reports, HNO3 was found to have a significant effect on γ for ClONO2: it is as low as one-half of that expected for the comparable HNO3-free solutions. The measured γ on sulfuric acid solutions at 203 ± 2 K are discussed in...
Ba9[NbN4]2O[Cn2] – Synthesis, Crystal Structure and Raman Spectrum

Red transparent single crystals of Ba 9 [NbN 4 ] 2 O[CN 2 ] were synthesised by the reaction of BaO coated Ba metal, C and Nb powder in arc-welded Nb ampoules at 1300 K. The title compound was characterised by X-ray single crystal diffraction (P1, a = 799.05(2), b = 962.61(2) and c = 1264.38(4) pm; a = 75.859(1), β = 85.745(1) and γ= 87.8621(8)°; Z = 2) and Raman spectroscopy (ν s y m = 1234 and 8 = 632/658/668 cm - 1 ). It now seems likely that a nitride-azide compound we previously reported, Ba 9 [NbN 4 ] 2 N[N 3 ], does not exist, but is in fact the title compound.
Enzymatic resolution of thiazole-containing vinyl carbinols. Synthesis of the C12–C21 fragment of the epothilones

Abstract An operationally simple enzymatic kinetic resolution has been applied in an efficient synthesis of C12–C21 fragment of epothilones. The key step, a lipase resolution, has been employed on three different thiazole-containing vinyl carbinol substrates to give highly enantiomerically enriched alcohols bearing the key C15 stereocenter.
Sequence and Structural Diversity of Mouse Y Chromosomes

Over the 180 My since their origin, the sex chromosomes of mammals have evolved a gene repertoire highly specialized for function in the male germline. The mouse Y chromosome is unique among mammalian Y chromosomes characterized to date in that it is large, gene-rich and euchromatic. Yet, little is known about its diversity in natural populations. Here, we take advantage of published whole-genome sequencing data to survey the diversity of sequence and copy number of sex-linked genes in three subspecies of house mice. Copy number of genes on the repetitive long arm of both sex chromosomes is highly variable, but sequence diversity in nonrepetitive regions is decreased relative to expectations based on autosomes. We use simulations and theory to show that this reduction in sex-linked diversity is incompatible with neutral demographic processes alone, but is consistent with recent positive selection on genes active during spermatogenesis. Our results support the hypothesis that the mouse sex chromosomes are engaged in ongoing intragenomic conflict.
Stable biphasic interfaces for open microfluidic platforms

We present an open microfluidic platform that enables stable flow of an organic solvent over an aqueous solution. The device features apertures connecting a lower aqueous channel to an upper solvent compartment that is open to air, enabling easy removal of the solvent for analysis. We have previously shown that related open biphasic systems enable steroid hormone extraction from human cells in microscale culture and secondary metabolite extraction from microbial culture; here we build on our prior work by determining conditions under which the system can be used with extraction solvents of ranging polarities, a critical feature for applying this extraction platform to diverse classes of metabolites. We developed an analytical model that predicts the limits of stable aqueous-organic interfaces based on analysis of Laplace pressure. With this analytical model and experimental testing, we developed generalized design rules for creating stable open microfluidic biphasic systems with solvents of varying densities, aqueous-organic interfacial tensions, and polarities. The stable biphasic interfaces afforded by this device will enable on-chip extraction of diverse metabolite structures and novel applications in microscale biphasic chemical reactions.
ZnTe6O13, a new ZnO-TeO2 phase.

Our investigations into the ZnO–TeO2 system have produced a new phase, zinc(II) hexa­tellurium(IV) trideca­oxide, ZnTe6O13, with trigonal (R\overline{3}) symmetry, synthesized by repeated heating and cooling to a maximum temperature of 1053 K. The asymmetric unit consists of a Zn atom coordinated in a distorted octa­hedral fashion by two unique tellurium(IV) oxide units that form trigonal–bipyramidal TeO4 and TeO3+1 corner- and edge-shared polyhedra. Except for the Zn and an O atom, which occupy 6c positions, all atoms occupy 18f general positions.
CS8GA11, A NEW ISOLATED CLUSTER IN A BINARY GALLIUM COMPOUND. A FAMILY OF VALENCE ANALOGUES A8TR11X : A = CS, RB; TR = GA, IN, TL; X = CL, BR, I

Fusion of the elements, and alkali-metal halide when appropriate, in stoichiometric amounts in Ta containers followed by slow cooling results in high yields of the title compounds. X-ray structures...
Functionalized azobenzenes through cross-coupling with organotrifluoroborates

The development of an azobenzene building block for Suzuki couplings and its application in the synthesis of photochromic agonists and antagonists is reported.
Microwave assisted solvent free amination of halo-(pyridine or pyrimidine) without transition metal catalyst

Abstract A solvent free direct amination of halo-(pyridine or pyrimidine) has been developed in good to high yields under computer-controlled microwave irradiation without transition metal catalyst. This reaction is a solvent and metal free, useful method for coupling of halo-(pyridine or pyrimidine) with pyrrolidine and piperidine derivatives by nucleophilic aromatic substitution (SNAr).
Total Synthesis of Seco (+)- and ent-(−)-Oxaduocarmycin SA: Construction of the (Chloromethyl)indoline Alkylating Subunit by a Novel Intramolecular Aryl Radical Cyclization onto a Vinyl Chloride

A practical, total synthesis of seco-(+)-oxaduocarmycin 3a, an analogue of the highly cytotoxic natural product, duocarmycin SA (1), is described. The 13-step synthesis features a novel and efficient intramolecular aryl radical cyclization onto a vinyl chloride as a direct entry to the (chloromethyl)indoline alkylating subunit 14. Subsequent resolution, utilizing a preparative Chiralpak AD column, provided enantiomerically pure alkylating subunits 14a and 14b which were elaborated to seco-(+) and ent-(−)-oxaduocarmycins, 3a and 3b, respectively. The natural enantiomer 3a was active at pM concentrations and exhibited 7−50-fold higher potentcy than its enantiomer 3b in in vitro cytotoxicity assays.
ROSAT Observations of X-Ray Emission from Planetary Nebulae

We have searched the entire ROSAT archive for useful observations to study X-ray emission from Galactic planetary nebulae (PNs). The search yields a sample of 63 PNs, which we call the ROSAT PN sample. About 20%-25% of this sample show X-ray emission; these include 13 definite detections and three possible detections (at a 2 σ level). All X-ray sources in these PNs are concentrated near the central stars. Only A30, BD +30°3639, and NGC 6543 are marginally resolved by the ROSAT instruments. Three types of X-ray spectra are seen in PNs. Type 1 consists of only soft X-ray emission (<0.5 keV), peaks at 0.1-0.2 keV, and can be fitted by blackbody models at temperatures 1-2 × 105 K. Type 2 consists of harder X-ray emission, peaks above 0.5 keV, and can be fitted by thin plasma emission models at temperatures of a few times 106 K. Type 3 is a composite of a bright type 1 component and a fainter type 2 component. Unresolved soft sources with type 1 spectra or the soft component of type 3 spectra are most likely photospheric emission from the hot central stars. Absorption cross sections are large for these soft-energy photons; therefore, only large, tenuous, evolved PNs with hot central stars and small absorption column densities have been detected. The origin of hard X-ray emission from PNs is uncertain. PNs with type 2 spectra are small, dense, young nebulae with relatively cool (105 K) central stars, while PNs with type 3 X-ray spectra are large, tenuous, evolved nebulae with hot central stars. The hard X-ray luminosities are also different between these two types of PNs, indicating perhaps different origins of their hard X-ray emission. Future Chandra and XMM observations with high spatial and spectral resolution will help to understand the origin of hard X-ray emission from PNs.
Synthesis and chemistry of N‐arylated pyrano[2,3‐c]pyrazoles

Novel N2-arylated pyrano[2,3-c]pyrazol-6-ones 2 can be prepared in a selective manner by generating the anion of 1 (RH) with lithium hexamethyldisilazide in DMF and quenching with activated aryl halides. Sterically demanding groups such as phenyl as in 5 reduce reactivity significantly while electronwithdrawing substituents such as trifluoromethyl and phenyl at C4 of the pyranone ring as in 10 and 15 render the pyranone carbonyl particularly susceptible to attack by nucleophiles resulting in ring-opening to give novel crotonyl derivatives. Proof of structure required a variety of nmr methods involving proton, carbon, and nitrogen nuclei.
Arachno, nido, and closo aromatic isomers of the Li6B6H6 molecule.

We analyzed chemical bonding in low-lying isomers of the recently computationally predicted B6H6Li6 molecule. According to our calculations the benzene-like B6H6Li6 (D2h, 1 A1g) arachno structure with the planar aromatic B6H6 6anion is the most stable one. A nido isomer with two aromatic B6H6 4- (pentagonal pyramid) and Li3 + (triangular) moieties, which can be considered as derived from the global minimum structure through a two-electron intramolecular transfer from B6H6 6- to three Li + cations, was found to be 10.7 kcal/mol higher in energy. A closo isomer with three aromatic moieties (octahedral B6H6 2- and two Li3 + ) was found to be 31.3 kcal/mol higher in energy than the global minimum. Another isomer with three aromatic moieties (two B3H3 2- and Li3 + ) was found to be substantially higher in energy (74.4 kcal/mol). Thus, the intramolecular electron transfers from the highly charged B6H6 6- anion to cations are not favorable for the B6H6Li6 molecule, even when a formation of three-dimensional aromatic B6H6 2anion and two U-aromatic Li3 + cations occurs in the closo isomer.
Novel Synthesis of 2-Oxo-4-phenyl-3-butynoic Acid, a New Inhibitor and Alternate Substrate of Pyruvate Decarboxylase

An improved method is reported for the synthesis of 2-oxo acids and is applied to the synthesis of 2-oxo-4-phenyl-3-butynoic acid. The compound is synthesized by reacting the N-methoxy-N-methylamide of monoethyloxalic acid with lithium phenylacetylide yielding ethyl 2-oxo-4-phenyl3-butynoate (78% yield), followed by strictly pH-controlled hydrolysis to the free acid in nearly quantitative yield. The compound in shown to be a potent irreversible inhibitor of brewers'yeast pyruvate decarboxylase, in addition to producing both cis- and trans-cinnamic acids as products of turnover. The formation of these isomeric cinnamic acids can be rationalized if the thiamin diphosphate-bound α-carbanion/enamine intermediate resulting from decarboxylation is protonated at the side chain γ carbon to form two diastereomeric allenols, whose tautomerization and hydrolysis lead to the two products
Alkene and Diene Hydrosilylations Catalyzed by Lanthanum Tris[bis(trimethylsilyl)amide]†

Commercially available lanthanum tris[bis(trimethylsilyl)amide] has been shown to be a very effective catalyst for hydrosilylations of representative alkenes and dienes in the presence of PhSiH3.
Synthesis of a bis-amino acid that creates a sharp turn

[reaction: see text] The synthesis of a new bis-amino acid 1 is presented. This monomer is designed to create a tightly curved structure when assembled into oligomers. The monomer is demonstrated to couple to the previously developed monomer 2 through pairs of amide bonds to create a strongly bent spiro-ladder oligomer. The structure of oligomer 3 was determined in aqueous solution using two-dimensional NMR.
Transparent titanium dioxide nanotubes: Processing, characterization, and application in establishing cellular response mechanisms.

Abstract The therapeutic applications of titanium dioxide nanotubes as osteogenic surface treatments for titanium-based implants are largely due to the finely tunable physical characteristics of these nanostructures. As these characteristics change, so does the cellular response, yet the exact mechanisms for this relationship remains largely undefined. We present a novel TiO2 NT imaging platform that is suitable for use with live-cell imaging techniques, thereby enabling, for the first time, dynamic investigation of those mechanisms. In this work, fabrication methods for producing transparent TiO2 NTs with diameters of 56 ± 6 nm, 75 ± 7 nm, 92 ± 9 nm, and 116 ± 10 nm are described. To demonstrate the diagnostic potential of these TiO2 NT imaging platforms, the focal adhesion protein vinculin and actin cytoskeletal filaments were fluorescently tagged in osteoblasts and real-time, high-resolution fluorescent microscopy of live-cell interactions with TiO2 NT substrates were observed. The scope of such a platform is expected to extend far beyond the current proof-of-concept, with great potential for addressing the dynamic response of cells interacting with nanostructured substrates. Statement of significance Titanium dioxide (TiO2) nanotubes are known to strongly enhance bone/mesenchymal stem cell behavior and, consequently, have gained attention as potential osteogenic surface treatments for titanium-bone implants. The exact mechanism by which TiO2 nanotubes influence cellular function remains controversial, partly due to limitations in existing cellular imaging methods with opaque substrates. This work identifies fabrication conditions for the successful production of transparent TiO2 nanotube arrays with tailorable diameters, as well as their functionality with pre-osteoblast mouse cells (MC3T3-E1) transfected with fluorescent focal adhesion protein vinculin and cytoskeletal filament actin. We demonstrate a means of recording live-cell, cell–substrate interaction mechanisms via high-resolution fluorescent microscopy and customizable, transparent TiO2 nanotubes to begin defining the relationship between TiO2 nanotube features and cell function.
Desmoplakin is required for epidermal integrity and morphogenesis in the Xenopus laevis embryo.

Desmoplakin (Dsp) is a unique and critical desmosomal protein, that is integral to epidermal development. However, it is unclear whether this protein is required specifically for epidermal morphogenesis. Using morpholinos or Crispr/Cas9 mutagenesis we decreased the function of Dsp in frog embryos to better understand its role during epidermal development. Dsp morphant and mutant embryos had developmental defects such as epidermal fragility that mimicked what has been reported in mammals. Most importantly, we also uncovered a novel function for Dsp in the morphogenesis of the epidermis in X. laevis. In particular, Dsp is required during the process of radial intercalation where basally located cells move into the outer epidermal layer. Once inserted these newly intercalated cells expand their apical surface and then they differentiate into specific epidermal cell types. Decreased levels of Dsp resulted in the failure of the radially intercalating cells to expand their apical surface, thereby reducing the number of differentiated multiciliated and secretory cells. Such defects correlate with changes in E-cadherin levels and actin and microtubule localization which could explain the defects in apical expansion. A mutated form of Dsp that maintains cell-cell adhesion but eliminates the connections to the cytoskeleton results in the same epidermal morphogenesis defect. These results suggest a specific role for Dsp in the apical expansion of cells during radial intercalation. We have developed a novel system, in the frog, to demonstrate for the first time that desmosomes not only protect against mechanical stress but are also critical for epidermal morphogenesis.
Diversity of Active Viral Infections within the Sphagnum Microbiome.

ABSTRACT Sphagnum-dominated peatlands play an important role in global carbon storage and represent significant sources of economic and ecological value. While recent efforts to describe microbial diversity and metabolic potential of the Sphagnum microbiome have demonstrated the importance of its microbial community, little is known about the viral constituents. We used metatranscriptomics to describe the diversity and activity of viruses infecting microbes within the Sphagnum peat bog. The vegetative portions of six Sphagnum plants were obtained from a peatland in northern Minnesota, and the total RNA was extracted and sequenced. Metatranscriptomes were assembled and contigs were screened for the presence of conserved virus marker genes. Using bacteriophage capsid protein gp23 as a marker for phage diversity, we identified 33 contigs representing undocumented phages that were active in the community at the time of sampling. Similarly, RNA-dependent RNA polymerase and the nucleocytoplasmic large DNA virus (NCLDV) major capsid protein were used as markers for single-stranded RNA (ssRNA) viruses and NCLDV, respectively. In total, 114 contigs were identified as originating from undescribed ssRNA viruses, 22 of which represent nearly complete genomes. An additional 64 contigs were identified as being from NCLDVs. Finally, 7 contigs were identified as putative virophage or polinton-like viruses. We developed co-occurrence networks with these markers in relation to the expression of potential-host housekeeping gene rpb1 to predict virus-host relationships, identifying 13 groups. Together, our approach offers new tools for the identification of virus diversity and interactions in understudied clades and suggests that viruses may play a considerable role in the ecology of the Sphagnum microbiome. IMPORTANCE Sphagnum-dominated peatlands play an important role in maintaining atmospheric carbon dioxide levels by modifying conditions in the surrounding soil to favor the growth of Sphagnum over that of other plant species. This lowers the rate of decomposition and facilitates the accumulation of fixed carbon in the form of partially decomposed biomass. The unique environment produced by Sphagnum enriches for the growth of a diverse microbial consortia that benefit from and support the moss9s growth, while also maintaining the hostile soil conditions. While a growing body of research has begun to characterize the microbial groups that colonize Sphagnum, little is currently known about the ecological factors that constrain community structure and define ecosystem function. Top-down population control by viruses is almost completely undescribed. This study provides insight into the significant viral influence on the Sphagnum microbiome and identifies new potential model systems to study virus-host interactions in the peatland ecosystem.
Bicyclo[2.2.2]octylidene

Abstract Bicyclo[2.2.2]octylidene is formed in four quite different ways. Reactions of the precursors do not complicate the chemistry of the carbene. The products are tricyclo[2.2.2.02,6]octane and bicyclo[2.2.2]octene, formed in approximately a 70:30 ratio.
Preparation of enantiomerically enriched α-alkoxystannanes by regioselective acetal exchange or acetal hydrolysis

Abstract α-alkoxyorganostannanes can be resolved via the methoxymenthyl ethers with subsequent regioselective acetal exchange or cleavage of the acetal group to the α-hydroxyalkylstannane.
Extended aromatic furan amidino derivatives as anti-Pneumocystis carinii agents.

The syntheses of nine new derivatives of 2,5-bis[4-(N-alkylamidino)phenyl]furans with extended aromatic systems are reported. The interaction of these dicationic furans with poly(dA)*poly(dT) and with the duplex oligomers d(CGCGAATTCGCG)2 and d(GCGAATTCGC)2 was determined by Tm measurement, and the effectiveness of these compounds against the immunosuppressed rat model of Pneumocystis carinii was evaluated. At a screening dose of 10 μmol/kg, 4 of the 12 amidino furans described here are more active than the parent compound 1. In general, extension of the aromatic system in the absence of a substitution of the amidino nitrogens resulted in higher affinity for DNA than the parent compound as judged by the larger ΔTm values and suggests enhanced van der Waals interactions in the amidino furan−DNA complex. Three of the compounds, 3, 5, and 11, yield cysts counts of less than 0.1% of control when administered at a dosage of 10 μmol/kg. Compound 3, which does not have an extended aromatic system, is the most ac...
δ-Amino β-Keto Esters, a Designed Polyfunctionalized Chiral Building Block for Alkaloid Synthesis. Asymmetric Synthesis of (R)-(+)-2-Phenylpiperidine and (−)-SS20846A

δ-Amino β-keto esters 3 and 11 are designed polyfunctionalized chiral building blocks for alkaloid synthesis and are prepared in one step from the corresponding sulfinimine (N-sulfinyl imine). Concise highly enantioselective four-step syntheses of 2-phenylpiperidine (7) and SS20846A (14) from 3 and 11, respectively, are described.
Preparation of diarylamines by the addition of 4-(N,N-dimethylamino)phenyllithium to nitroarenes

Abstract The addition of 4-(N,N-dimethylamino)phenyllithium to nitroarenes in THF (−78°C) affords the corresponding diarylamines in one-pot and the reaction appears to be general in scope. A ‘nitroso’-based mechanism is proposed for this novel nitroreductive N-arylation reaction.
XBART: Accelerated Bayesian Additive Regression Trees

Bayesian additive regression trees (BART) (Chipman et. al., 2010) is a powerful predictive model that often outperforms alternative models at out-of-sample prediction. BART is especially well-suited to settings with unstructured predictor variables and substantial sources of unmeasured variation as is typical in the social, behavioral and health sciences. This paper develops a modified version of BART that is amenable to fast posterior estimation. We present a stochastic hill climbing algorithm that matches the remarkable predictive accuracy of previous BART implementations, but is many times faster and less memory intensive. Simulation studies show that the new method is comparable in computation time and more accurate at function estimation than both random forests and gradient boosting.
Learning End-to-End Goal-Oriented Dialog with Maximal User Task Success and Minimal Human Agent Use

Neural end-to-end goal-oriented dialog systems showed promise to reduce the workload of human agents for customer service, as well as reduce wait time for users. However, their inability to handle new user behavior at deployment has limited their usage in real world. In this work, we propose an end-to-end trainable method for neural goal-oriented dialog systems which handles new user behaviors at deployment by transferring the dialog to a human agent intelligently. The proposed method has three goals: 1) maximize user's task success by transferring to human agents, 2) minimize the load on the human agents by transferring to them only when it is essential and 3) learn online from the human agent's responses to reduce human agents load further. We evaluate our proposed method on a modified-bAbI dialog task that simulates the scenario of new user behaviors occurring at test time. Experimental results show that our proposed method is effective in achieving the desired goals.
On Partial Covering For Geometric Set Systems

We study a generalization of the Set Cover problem called the Partial Set Cover in the context of geometric set systems. The input to this problem is a set system (X, R), where X is a set of elements and R is a collection of subsets of X, and an integer k <= |X|. Each set in R has a non-negative weight associated with it. The goal is to cover at least k elements of X by using a minimum-weight collection of sets from R. The main result of this article is an LP rounding scheme which shows that the integrality gap of the Partial Set Cover LP is at most a constant times that of the Set Cover LP for a certain projection of the set system (X, R). As a corollary of this result, we get improved approximation guarantees for the Partial Set Cover problem for a large class of geometric set systems.
Dispersive geometric curve flows

The Hodge star mean curvature flow on a 3-dimension Riemannian or pseudo-Riemannian manifold, the geometric Airy flow on a Riemannian manifold, the Schrodingier flow on Hermitian manifolds, and the shape operator curve flow on submanifolds are natural non-linear dispersive curve flows in geometric analysis. A curve flow is integrable if the evolution equation of the local differential invariants of a solution of the curve flow is a soliton equation. For example, the Hodge star mean curvature flow on $R^3$ and on $R^{2,1}$, the geometric Airy flow on $R^n$, the Schrodingier flow on compact Hermitian symmetric spaces, and the shape operator curve flow on an Adjoint orbit of a compact Lie group are integrable. In this paper, we give a survey of these results, describe a systematic method to construct integrable curve flows from Lax pairs of soliton equations, and discuss the Hamiltonian aspect and the Cauchy problem of these curve flows.
Phase disruption as a new design paradigm for optimizing the nonlinear-optical response

The intrinsic optical nonlinearities of linear structures, including conjugated chain polymers and nanowires, are shown to be dramatically enhanced by the judicious placement of a charge-diverting path sufficiently short to create a large phase disruption in the dominant eigenfunctions along the main path of the probability current. Phase disruption is proposed as a new general principle for the design of molecules, nanowires, and any quasi-1D quantum system with large intrinsic response and does not require charge donor-acceptors at the ends.
The PRIORI Emotion Dataset: Linking Mood to Emotion Detected In-the-Wild.

Bipolar Disorder is a chronic psychiatric illness characterized by pathological mood swings associated with severe disruptions in emotion regulation. Clinical monitoring of mood is key to the care of these dynamic and incapacitating mood states. Frequent and detailed monitoring improves clinical sensitivity to detect mood state changes, but typically requires costly and limited resources. Speech characteristics change during both depressed and manic states, suggesting automatic methods applied to the speech signal can be effectively used to monitor mood state changes. However, speech is modulated by many factors, which renders mood state prediction challenging. We hypothesize that emotion can be used as an intermediary step to improve mood state prediction. This paper presents critical steps in developing this pipeline, including (1) a new in the wild emotion dataset, the PRIORI Emotion Dataset, collected from everyday smartphone conversational speech recordings, (2) activation/valence emotion recognition baselines on this dataset (PCC of 0.71 and 0.41, respectively), and (3) significant correlation between predicted emotion and mood state for individuals with bipolar disorder. This provides evidence and a working baseline for the use of emotion as a meta-feature for mood state monitoring.
A note on secondary K-theory

We prove that Toen’s secondary Grothendieck ring is isomorphic to the Grothendieck ring of smooth proper pretriangulated dg categories previously introduced by Bondal, Larsen, and Lunts. Along the way, we show that those short exact sequences of dg categories in which the first term is smooth proper and the second term is proper are necessarily split. As an application, we prove that the canonical map from the derived Brauer group to the secondary Grothendieck ring has the following injectivity properties: in the case of a commutative ring of characteristic zero, it distinguishes between dg Azumaya algebras associated to nontorsion cohomology classes and dg Azumaya algebras associated to torsion cohomology classes (= ordinary Azumaya algebras); in the case of a field of characteristic zero, it is injective; in the case of a field of positive characteristic p, it restricts to an injective map on the p-primary component of the Brauer group.
Bounds on the quantum satisfiability threshold

Quantum k-SAT is the problem of deciding whether there is a n-qubit state which is perpendicular to a set of vectors, each of which lies in the Hilbert space of k qubits. Equivalently, the problem is to decide whether a particular type of local Hamiltonian has a ground state with zero energy. We consider random quantum k-SAT formulas with n variables and m = αn clauses, and ask at what value of α these formulas cease to be satisfiable. We show that the threshold for random quantum 3-SAT is at most 3.594. For comparison, convincing arguments from statistical physics suggest that the classical 3-SAT threshold is αc ≈ 4.267. For larger k, we show that the quantum threshold is a constant factor smaller than the classical one. Our bounds work by determining the generic rank of the satisfying subspace for certain gadgets, and then using the technique of differential equations to analyze various algorithms that partition the hypergraph into a collection of these gadgets.