cssi/SciSciGPT-SciSciNet huggingface dataset:
Combining pair-density functional theory and variational two-electron reduced-density matrix methods

Complete active space self-consistent field (CASSCF) computations can be realized at polynomial cost via the variational optimization of the active-space two-electron reduced-density matrix (2-RDM). Like conventional approaches to CASSCF, variational 2-RDM (v2RDM) driven CASSCF captures nondynamical electron correlation in the active space, but it lacks a description of the remaining dynamical correlation effects. Such effects can be modeled through a combination of v2RDM-CASSCF and on-top pair-density functional theory (PDFT). The resulting v2RDM-CASSCF-PDFT approach provides a computationally inexpensive framework for describing both static and dynamical correlation effects in multiconfigurational and strongly correlated systems. On-top pair-density functionals can be derived from familiar Kohn–Sham exchange–correlation (XC) density functionals through the translation of the v2RDM-CASSCF reference densities [Li Manni et al. J. Chem. Theory Comput. 2014, 10, 3669−3680]. Translated and fully translated on...
Computing Walrasian equilibria: fast algorithms and structural properties

We present the first polynomial time algorithm for computing Walrasian equilibrium in an economy with indivisible goods and general buyer valuations having only access to an aggregate demand oracle, i.e., an oracle that given prices on all goods, returns the aggregated demand over the entire population of buyers. For the important special case of gross substitute valuations, our algorithm queries the aggregate demand oracle $${\widetilde{O}}(n)$$ times and takes $${\widetilde{O}}(n^3)$$ time, where n is the number of goods and the $${\widetilde{O}}(\cdot )$$ notation denotes an asymptotic bound up to polylogarithmic factors. Both algorithms are randomized. At the heart of our solution is a method for exactly minimizing certain convex functions which cannot be evaluated but for which the subgradients can be computed. We also give the fastest known algorithm for computing Walrasian equilibrium for gross substitute valuations in the value oracle model. Our algorithm has running time $${\widetilde{O}}((mn + n^3) T_V)$$ where $$T_V$$ is the cost of querying the value oracle. A key technical ingredient is to regularize a convex programming formulation of the problem in a way that subgradients are cheap to compute. En route, we give necessary and sufficient conditions for the existence of robust Walrasian prices, i.e., prices for which each agent has a unique demanded bundle and the demanded bundles clear the market. When such prices exist, the market can be perfectly coordinated by solely using prices.
Managerial Optimism in a Competitive Market

Research has shown that many managers and entrepreneurs tend to be optimistic and are inclined to believe that negative shocks happen to them less frequently than to others. However, there is also evidence suggesting that such optimism is often inaccurate in reality and managerial optimism can lead to the failure of a company. We develop a game‐theoretic model to investigate the impact of managerial optimism on firms’ performance in a competitive market. Our analysis shows that a manager's optimism about demand can increase the firm's profit. Moreover, only one firm having managerial optimism can be win–win for both firms in a duopoly, because it can increase the level of product quality differentiation between the firms, alleviating price competition. However, if both firms have optimistic managers, the benefit of increased differentiation disappears, and firms are weakly worse off, compared with the case of both firms having realistic managers. Our research suggests that a firm should hire a realistic manager when managerial optimism is already pervasive in a competitive market.
A theory of self-enforcing monetary constitutions with reference to the Suffolk System, 1825–1858

Abstract We develop a theory of self-enforcing monetary constitutions. A monetary constitution is the framework of rules within which money-providing and money-using agents interact. A self-enforcing monetary constitutions is upheld by the agents acting within the system; it thus does not require external enforcement. We describe how the institutional technology of polycentric sovereignty applies to monetary constitutions, and show how the 19th century Suffolk banking system was characterized by polycentric sovereignty, rendering its (de facto) monetary constitution self-enforcing. We conclude by briefly discussing the implications of our analysis for the role of the state in maintaining healthy money and banking systems.
Graph Invertibility

Extending the work of Godsil and others, we investigate the notion of the inverse of a graph (specifically, of bipartite graphs with a unique perfect matching). We provide a concise necessary and sufficient condition for the invertibility of such graphs and generalize the notion of invertibility to multigraphs. We examine the question of whether there exists a "litmus subgraph" whose bipartiteness determines invertibility. As an application of our invertibility criteria, we quickly describe all invertible unicyclic graphs. Finally, we describe a general combinatorial procedure for iteratively constructing invertible graphs, giving rise to large new families of such graphs.
Keyphrase Extraction from Disaster-related Tweets

While keyphrase extraction has received considerable attention in recent years, relatively few studies exist on extracting keyphrases from social media platforms such as Twitter, and even fewer for extracting disaster-related keyphrases from such sources. During a disaster, keyphrases can be extremely useful for filtering relevant tweets that can enhance situational awareness. Previously, joint training of two different layers of a stacked Recurrent Neural Network for keyword discovery and keyphrase extraction had been shown to be effective in extracting keyphrases from general Twitter data. We improve the model's performance on both general Twitter data and disaster-related Twitter data by incorporating contextual word embeddings, POS-tags, phonetics, and phonological features. Moreover, we discuss the shortcomings of the often used F1-measure for evaluating the quality of predicted keyphrases with respect to the ground truth annotations. Instead of the F1-measure, we propose the use of embedding-based metrics to better capture the correctness of the predicted keyphrases. In addition, we also present a novel extension of an embedding-based metric. The extension allows one to better control the penalty for the difference in the number of ground-truth and predicted keyphrases.
Breaking the Law Under Competitive Pressure

When a business has competitors that break a burdensome law, is it morally required to obey this law, or may it break the law to avoid an unfair competitive disadvantage? Though this ethical question is pervasive in the business world, many non-skeptical theories of the obligation to obey the law cannot give it a clear answer. A broadly Kantian account, by contrast, can explain why businesspeople ought to obey laws of a certain type even under competitive pressure, namely laws that play a direct role in defining rights to use physical or financial resources free from substantial interference. Businesspeople must obey these laws even at the cost of allowing their businesses to fail and even when the acts proscribed are mala prohibita. This argument for obeying the law in competitive contexts has limited scope. Considerations of fairness or self-preservation may justify violating laws of other types under competitive pressure.
Robust Determination of Protein Allosteric Signaling Pathways.

To understand how protein function changes upon an allosteric perturbation, such as ligand binding and mutation, significant progress in characterizing allosteric network from molecular dynamics (MD) simulations has been made. However, determining which amino acid(s) play an essential role in the propagation of signals may prove challenging, even when the location of the source and sink is known for a protein or protein complex. This challenge is mainly due to the large fluctuations in protein dynamics that cause instability of the network topology within a single trajectory or between multiple replicas. To solve this problem, we introduce the current-flow betweenness scheme, originated from electrical network theory, to protein dynamical network analysis. To demonstrate the benefit of this new method, we chose a prototypic allosteric enzyme (IGPS or HisH-HisF dimer) as our benchmark system. Using multiple replicas of simulations and multiple network topology comparison metrics (edge ranking, path length,...
Healthcare and Financial Decision Making and Incident Adverse Cognitive Outcomes among Older Adults.

OBJECTIVES To determine if poorer healthcare and financial decision making forecasts adverse cognitive outcomes in old age. Specifically, we hypothesized that poorer decision making would be associated with an increased risk of incident Alzheimer's dementia, an increased risk of incident mild cognitive impairment (MCI), and a more rapid decline in cognition. DESIGN An ongoing prospective observational cohort study of aging (the Rush Memory and Aging Project). SETTING The greater Chicago area. PARTICIPANTS A total of 952 community-based older adults without dementia at baseline. MEASUREMENTS Participants completed a measure of healthcare and financial decision making at baseline and underwent annual standardized evaluations to track clinical status and cognitive functions (global cognition, episodic memory, semantic memory, working memory, perceptual speed, and visuospatial ability). RESULTS During up to 9 years of follow-up (M = 5.2 y; standard deviation = 2.7), 156 participants developed Alzheimer's dementia (16.4% of 952), 253 participants developed MCI (33.2% of 760), and each cognitive measure declined (all Ps < .001). In Cox proportional hazards models adjusted for age, sex, and education, poorer decision making was associated with an increased risk of incident Alzheimer's dementia (hazard ratio [HR] = 1.17; 95% confidence interval [CI] = 1.10-1.24; P < .001) and incident MCI (HR = 1.16; 95% CI = 1.10-1.22; P < .001). Further, in linear mixed-effects models, poorer decision making among those who were initially free of cognitive impairment was associated with a more rapid decline in global cognition and four of five specific cognitive domains (all Ps < .05). CONCLUSION Our results suggest that poorer healthcare and financial decision making heralds adverse cognitive outcomes in old age. J Am Geriatr Soc 67:1590-1595, 2019.
Bounded Rationality and the Theory of Property

Strong, property rule protection – implemented via injunctions, criminal sanctions and supercomepnsatory damages – is a defining aspect of property. What is the theoretical justification for property rule protection? The conventional answer has to do with the alleged shortcomings of the weaker, liability rule alternative: It is widely held that liability rule protection – implemented via compensatory damages – would interfere with efficient exchange and jeopardize the market system. We show that these concerns are overstated and that exchange efficiency generally obtains in a liability rule regime. But only when the parties are perfectly rational. When the standard rationality assumption is replaced with a more realistic, bounded rationality assumption, liability rules no longer support exchange efficiency. Bounded rationality thus emerges as a foundational element in the theory of property.
Lithium Diffusion Mechanism through Solid–Electrolyte Interphase in Rechargeable Lithium Batteries

The composition, structure, and the formation mechanism of the solid–electrolyte interphase (SEI) in lithium-based (e.g., Li-ion and Li metal) batteries have been widely explored in the literature....
Pun Generation with Surprise

We tackle the problem of generating a pun sentence given a pair of homophones (e.g., “died” and “dyed”). Puns are by their very nature statistically anomalous and not amenable to most text generation methods that are supervised by a large corpus. In this paper, we propose an unsupervised approach to pun generation based on lots of raw (unhumorous) text and a surprisal principle. Specifically, we posit that in a pun sentence, there is a strong association between the pun word (e.g., “dyed”) and the distant context, but a strong association between the alternative word (e.g., “died”) and the immediate context. We instantiate the surprisal principle in two ways: (i) as a measure based on the ratio of probabilities given by a language model, and (ii) a retrieve-and-edit approach based on words suggested by a skip-gram model. Based on human evaluation, our retrieve-and-edit approach generates puns successfully 30% of the time, doubling the success rate of a neural generation baseline.
Corpora Generation for Grammatical Error Correction

Grammatical Error Correction (GEC) has been recently modeled using the sequence-to-sequence framework. However, unlike sequence transduction problems such as machine translation, GEC suffers from the lack of plentiful parallel data. We describe two approaches for generating large parallel datasets for GEC using publicly available Wikipedia data. The first method extracts source-target pairs from Wikipedia edit histories with minimal filtration heuristics while the second method introduces noise into Wikipedia sentences via round-trip translation through bridge languages. Both strategies yield similar sized parallel corpora containing around 4B tokens. We employ an iterative decoding strategy that is tailored to the loosely supervised nature of our constructed corpora. We demonstrate that neural GEC models trained using either type of corpora give similar performance. Fine-tuning these models on the Lang-8 corpus and ensembling allows us to surpass the state of the art on both the CoNLL ‘14 benchmark and the JFLEG task. We present systematic analysis that compares the two approaches to data generation and highlights the effectiveness of ensembling.
For want of a chair: Teaching price formation using a cap and trade game

“Cap and trade” is one of the most innovative policy options developed by environmental economists. By placing a cap on a social bad and allowing firms to buy and sell the right to generate it, pol...
Comparison of the Optical Properties of Er3+ Doped Gallium Nitride Prepared by Metalorganic Molecular Beam Epitaxy (Mombe) and Solid Source Molecular Beam Epitaxy (SSMBE)

We report on the luminescence properties of Er doped GaN grown prepared by metalorganic molecular beam epitaxy (MOMBE) and solid-source molecular beam epitaxy (SSMBE) on Si substrates. Both types of samples emitted characteristic 1.54 µm PL resulting from the intra-4f Er3+ transition 4I13/2→4I15/2. Under below-gap excitation the samples exhibited very similar 1.54 µm PL intensities. On the contrary, under above-gap excitation GaN: Er (SSMBE) showed ∼80 times more intense 1.54 µm PL than GaN: Er (MOMBE). In addition, GaN: Er (SSMBE) also emitted intense green luminescence at 537 nm and 558 nm, which was not observed from GaN: Er (MOMBE). The average lifetime of the green PL was determined to be 10.8 µs at 15 K and 5.5 µs at room temperature. A preliminary lifetime analysis suggests that the decrease in lifetime is mainly due to the strong thermalization between the 2H11/2 and 4S3/2 excited states. Nonradiative decay processes are expected to only weakly affect the green luminescence.
Corporate Strategy and Network Change

Networks change when either the ties or the nodes are modified. Research on interfirm networks has conceptualized network change as being driven almost exclusively by modifications in ties (additio...
An example of non-existence of Riley equilibrium in markets with adverse selection

Rothschild and Stiglitz [1976] proposed a model of a competitive market with adverse selection and showed that a (pure strategy) Nash equilibrium may not exist. Among the solutions proposed to deal with this problem, a particularly influential one is the notion of Riley (or reactive) equilibrium [Riley, 1979]. We give an example that shows that a Riley equilibrium may not exist if consumers are not ordered.
Secularizing a Religious Legal System: Ecclesiastical Jurisdiction in Early Eighteenth Century England

The constitutional position of the English ecclesiastical courts remained a divisive subject after 1688, as demonstrated by a range of printed sources from the early eighteenth century including visitation charges, law books, and political pamphlets. This theoretical debate culminated in challenges to ecclesiastical jurisdiction in Parliament and Hardwicke's famous decision in Middleton v. Crofts, which represented a significant advance toward a contractarian view of religious authority.
Ab initio calculations on 1,3,2-diazaphospholes: New heteroaromatic systems

Abstract Ab initio calculations on three 1,3,2-diazaphosphole derivatives [(MP2/6-31G(d,p)] gave rise to structural and energetic data that are interpreted in context of aromaticity. The 1,3,2-diazaphospholenium ion is shown to have a degree of aromatic stabilization energy (24.0 kcal/mol) comparable to that of pyrrole. Cyclic delocalization is supported by analysis of computed charge distribution data, natural bond orbital data, bond lengths, and magnetic susceptibility data.
EPR spectra of C60 anions

The broad and sharp EPR signals observed in spectra of C60 and C 60 3− are summarized and proposed assignments are discussed. The sharp signals in samples of C 60 2− are reviewed.
A High-Yield Route to 1,2-Dihydrocyclobutabenzene-3,6-dicarboxylic Acid

A simple five-step method for preparing the previously unknown 1,2-dihydrocyclobutabenzene-3,6-dicarboxylic acid (XTA) in high yield is presented. All intermediates were crystalline compounds which allowed the preparation to be scaled up without complication. The title compound is of interest as a crosslinkable derivative of the widely used monomer, terephthalic acid (TA)
Gαq sensitizes TRPM8 to inhibition by PI(4,5)P2 depletion upon receptor activation

The cold and menthol sensitive Transient Receptor Potential Melastatin 8 (TRPM8) channel is important for both physiological temperature detection and cold allodynia. Activation of G-protein coupled receptors (GPCRs) by pro-inflammatory mediators inhibits these channels. It was proposed that this inhibition proceeds via direct binding of Gαq to the channel. TRPM8 requires the plasma membrane phospholipid phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2 or PIP2] for activity. It was claimed however that a decrease in cellular levels of this lipid upon receptor activation does not contribute to channel inhibition. Here we show that supplementing the whole cell patch pipette with PI(4,5)P2 reduced inhibition of TRPM8 by activation of Gαq-coupled receptors in mouse dorsal root ganglion (DRG) neurons isolated from both sexes. Stimulating the same receptors activated Phospholipase C (PLC) and decreased plasma membrane PI(4,5)P2 levels in these neurons. PI(4,5)P2 also reduced inhibition of TRPM8 by activation of heterologously expressed Gαq-coupled muscarinic M1 receptors. Co-expression of a constitutively active Gαq protein that does not couple to PLC inhibited TRPM8 activity, and in cells expressing this protein decreasing PI(4,5)P2 levels using a voltage sensitive 5′-phosphatase induced a stronger inhibition of TRPM8 activity than in control cells. Our data indicate that upon GPCR activation, Gαq binding reduces the apparent affinity of TRPM8 for PI(4,5)P2 and thus sensitizes the channel to inhibition induced by decreasing PI(4,5)P2 levels. SIGNIFICANCE STATEMENT Increased sensitivity to heat in inflammation is partially mediated by inhibition of the cold- and menthol sensitive TRPM8 ion channels. Most inflammatory mediators act via GPCR-s that activate the Phospholipase C pathway leading to the hydrolysis of PI(4,5)P2. How receptor activation by inflammatory mediators leads to TRPM8 inhibition is not well understood. Here we propose that direct binding of Gαq both reduces TRPM8 activity, and sensitizes the channel to inhibition by decreased levels of its cofactor PI(4,5)P2. Our data demonstrate the convergence of two downstream effectors of receptor activation Gαq and PI(4,5)P2 hydrolysis in regulation of TRPM8.
Superacid catalyzed ring-opening reactions involving 2-oxazolines and the role of superelectrophilic intermediates

Abstract A variety of 2-oxazolines are found to react with arenes in superacidic triflic acid, CF 3 SO 3 H. It is proposed that the 2-oxazolines are protonated twice in triflic acid and the resulting intermediates undergo ring-opening reactions to produce reactive, dicationic species. These superelectrophiles are capable of reacting with benzene and o -dichlorobenzene in high yields by Friedel–Crafts type reactions.
A new method for the selective oxidation of allylic and benzylic alcohols

A new method is described for the selective oxidation of allylic or benzylic alcohols, in the presence of saturated alcohols, using trimethylamine-N-oxide in the presence of an iron carbonyl.
Design, synthesis, application and recovery of a minimally fluorous diaryl diselenide for the catalysis of stannane-mediated radical chain reactions

Abstract The synthesis of a minimally fluorous (52% F) diaryl diselenide is described. On reduction in situ with tributylstannane this diselenide provides a fluorous selenol which is effective in inhibiting a range of stannane-mediated radical rearrangements, including a cyclopropylcarbinyl ring opening. A method for the recovery of the fluorous diselenide involving continuous extraction in a modified, cooled continuous extractor is described.
The modulated structure of Co3Al4Si2: incommensurability and Co-Co interactions in search of filled octadecets.

Incommensurate modulations are increasingly being recognized as a common phenomenon in solid-state compounds ranging from inorganic materials to molecular crystals. The origins of such modulations are often mysterious, but appear to be as diverse as the compounds in which they arise. In this Article, we describe the crystal structure and bonding of Co3Al4Si2, the δ phase of the Co-Si-Al system, whose modulated structure can be traced to a central concept of inorganic chemistry: the 18 electron rule. The structure is monoclinic, conforming to the 3 + 1D superspace group C/2m(0β0)s0. The basis of the crystal structure is a rod packing of columns of the fluorite (CaF2) type, a theme that is shared by the recently determined structure of Fe8Al(17.4)Si(7.6). The columns are arranged into sheets, within which the fluorite structure's primitive cubic network of Si/Al atoms continues uninterrupted from column to column. Between the sheets, layers of interstitial Si/Al atoms occur, some of which are arranged with a periodicity incommensurate with that of the fluorite-type columns. Strong modulations in the interstitial layers result. Electronic structure calculations, using a DFT-calibrated Huckel model on a commensurate approximate structure, reveal that the complex pattern of atoms within these interstitial layers serves to distribute Si/Al atoms around the Co atoms in order to reach 18 electron counts (filled octadecets). Central to this bonding scheme is the covalent sharing of electron pairs between Co atoms. The shared electron pairs occupy orbitals that are isolobal to classical Co-Co σ and π bonds, but whose stability is tied to multicenter character involving bridging Si/Al atoms. Through these features, Co3Al4Si2 expands the structural and electronic manifestations of the 18 electron rule in solid-state inorganic compounds.
Amide bond formation from selenocarboxylates and aromatic azides

Abstract A new method of amide bond formation was developed through the reaction of potassium selenocarboxylates with aromatic azides at room temperature. Potassium selenocarboxylates were prepared in situ by the treatment of diacyl selenides with potassium methoxide at 5 °C under N2. After the addition of azide, the reaction was allowed to gradually warm to room temperature and was stirred for 0.5–2 h. Excellent yields were obtained when electron deficient aromatic azides were used.
DEFINITION OF THE EFFECT AND ROLE OF THE BLEOMYCIN A2 VALERATE SUBSTITUENTS : PREORGANIZATION OF A RIGID, COMPACT CONFORMATION IMPLICATED IN SEQUENCE- SELECTIVE DNA CLEAVAGE

The synthesis and a comparative study of deglycobleomycin A2 analogues containing key modifications in the valerate subunit are described in efforts that define the role of the linker length and it...
Synthesis of Substituted Bicyclo[2.2.2]octatrienes

An efficient route to bicyclo[2.2.2]octatriene, barrelene, and substituted versions of this molecule has been developed starting from the benzene equivalent cis-3,5-cyclohexadiene-1,2-diol. Following the Diels−Alder reaction of this molecule with an activated acetylene, conversion of the diol to the final olefin was accomplished through formation of a thiocarbonate intermediate and subsequent reaction with 1,3-dimethyl-2-phenyl-1,3,2-diazaphospholidine (DPD). The synthesis developed allows a variety of barrelenes to be prepared in as few as three steps from commercially available starting materials.
Asymmetric deprotonation and complexation reactions mediated by chiral ketals as a route to ortho-disubstituted (η6-arene)Cr(CO)3 complexes

A series of chiral ketals derived from an aryl ketone or aldehyde and one of several C 2 -symmetrical diols were converted to their corresponding (η 6 -arene)Cr(CO) 3 complexes. The resultant 1,3-dioxolanes were trans substituted at C-4 and C-5 by groups CH 2 X, where X=H(1), OCH 3 (2), or N(CH 3 ) 2 (3). Ortho deprotonation was attempted on complexes 1-3 using tert-butyllithium in THF solution to afford the corresponding lithio derivatives
Reaction of Fischer Carbene Complexes with 1,3-Butadiynes: A New Strategem for Biaryl Synthesis with Construction of the Biaryl Bond Preceding Synthesis of the Arenes

The first examples of the reactions of Fischer carbene complexes with 1,3-butadiynes are reported. These reactions are of interest since they provide new methods for the synthesis of acetylenic substituted arenes and also for the synthesis of biaryls. The reactions of the complexes (CO)5CrC(OR1)R2 [R1 = Me, n-Bu; R2 = phenyl, 1-naphthyl, 1-cyclohexenyl] were investigated with the conjugated diynes R3C⋮CC⋮CR3 [R3 = t-Bu, i-Pr, Ph]. All of the carbene complexes will react with 1 equiv of the diyne to give good yields of acetylenic arenes 5, 19, and 23, each with high selectivity for the regioisomer in which the substituent R3 on the diyne is incorporated adjacent to the phenol function. The reactions of the alkynylarenes 5, 19, and 23 with a second equivalent of carbene complexes, 4, 16, and 22, respectively, generate the bis-phenols 26, 31, and 33, with varying amounts of five-membered-ring annulated compounds as side products. These side products are not seen with the cyclohexenyl complex 22 and can be mi...
Checking It Twice: Does Adding Spelling and Grammar Checkers Improve Essay Quality in an Automated Writing Tutor?

This study investigated the effect of incorporating spelling and grammar checking tools within an automated writing tutoring system, Writing Pal. High school students (n = 119) wrote and revised six persuasive essays. After initial drafts, all students received formative feedback about writing strategies. Half of the participants were also given access to spelling and grammar checking tools during the writing and revision periods. Linear mixed effects models revealed that essay quality for students in both conditions improved from initial draft to revision in terms of all aspects except essay unity. The availability of spelling and grammar checking yielded added improvements from initial draft to revision for several aspects of essay quality (i.e., conclusion, organization, voice, grammar/mechanics, and word choice), but other aspects were unaffected (i.e., introduction, body, unity, and sentence structure). The availability of spelling and grammar checking tools had no effect on holistic essay scores. These results indicate that automated spelling and grammar feedback contribute to modest, incremental improvements in writing quality that may complement automated strategy feedback.
Is Attention Interpretable

Attention mechanisms have recently boosted performance on a range of NLP tasks. Because attention layers explicitly weight input components’ representations, it is also often assumed that attention can be used to identify information that models found important (e.g., specific contextualized word tokens). We test whether that assumption holds by manipulating attention weights in already-trained text classification models and analyzing the resulting differences in their predictions. While we observe some ways in which higher attention weights correlate with greater impact on model predictions, we also find many ways in which this does not hold, i.e., where gradient-based rankings of attention weights better predict their effects than their magnitudes. We conclude that while attention noisily predicts input components’ overall importance to a model, it is by no means a fail-safe indicator.
Electrochemical Oxidation of Molybdenum Metal in 0.5 M H2SO4 Studied by Core and Valence Band X-ray Photoelectron Spectroscopy and Interpreted by Band Structure Calculations

The behavior of molybdenum metal in 0.5 M sulfuric acid treated at various potentials has been studied using core and valence band X-ray photoelectron spectroscopy in a previously described anaerob...
Copper-catalyzed enantioselective conjugate addition of diethylzinc to acyclic enones in the presence of planar-chiral phosphaferrocene-oxazoline ligands.

A new subclass of chiral phosphaferrocene-oxazoline ligands has been applied to the copper-catalyzed asymmetric conjugate addition of diethylzinc to acyclic enones, furnishing good enantioselectivity. The ligand design readily lends itself to modification, thereby facilitating optimization of ee. Although the dominant stereocontrol element in these 1,4-addition processes is the central chirality of the oxazoline subunit of the ligand, not the planar chirality of the phosphaferrocene, altering the phosphaferrocene subunit can provide useful enhancement of enantioselectivity.
Cyclization reactions of molybdenum and chromium carbene complexes with enynes

Abstract Thermolysis of enynes with pentacarbonyl(butylmethoxycarbene)molybdenum (0) 1a produces vinylcyclopropanes in significantly higher yields than the analogous chromium carbene complexes 1b and 3. Additionally, enynes with an allylic ether substituent are shown to cyclize to vinylcyclopropanes in good to excellent yield.
Stable Host Gene Expression in the Gut of Adult Drosophila melanogaster with Different Bacterial Mono-Associations

There is growing evidence that the microbes found in the digestive tracts of animals influence host biology, but we still do not understand how they accomplish this. Here, we evaluated how different microbial species commonly associated with laboratory-reared Drosophila melanogaster impact host biology at the level of gene expression in the dissected adult gut and in the entire adult organism. We observed that guts from animals associated from the embryonic stage with either zero, one or three bacterial species demonstrated indistinguishable transcriptional profiles. Additionally, we found that the gut transcriptional profiles of animals reared in the presence of the yeast Saccharomyces cerevisiae alone or in combination with bacteria could recapitulate those of conventionally-reared animals. In contrast, we found whole body transcriptional profiles of conventionally-reared animals were distinct from all of the treatments tested. Our data suggest that adult flies are insensitive to the ingestion of the bacteria found in their gut, but that prior to adulthood, different microbes impact the host in ways that lead to global transcriptional differences observable across the whole adult body.
Arenediazonium salts immobilized in imidazolium ionic liquids as electrophilic partners in the Pd(OAc)2-catalyzed Matsuda–Heck arylation

Abstract The utility of arenediazonium salts immobilized in imidazolium-ILs [BMIMPF6 and BMIMBF4] for facile, high yielding, synthesis of olefins via the Pd(OAc)2-catalyzed Matsuda–Heck arylation reaction has been demonstrated. The reaction can also be performed as a two-step process in the IL starting from ArNH2, by sequential in-situ diazotization–arylation. Simple product isolation and the recycling/re-use of the IL are additional advantages of this one-pot method.
SATORI: a system for ontology-guided visual exploration of biomedical data repositories

Motivation The ever-increasing number of biomedical datasets provides tremendous opportunities for re-use but current data repositories provide limited means of exploration apart from text-based search. Ontological metadata annotations provide context by semantically relating datasets. Visualizing this rich network of relationships can improve the explorability of large data repositories and help researchers find datasets of interest. Results We developed SATORI-an integrative search and visual exploration interface for the exploration of biomedical data repositories. The design is informed by a requirements analysis through a series of semi-structured interviews. We evaluated the implementation of SATORI in a field study on a real-world data collection. SATORI enables researchers to seamlessly search, browse and semantically query data repositories via two visualizations that are highly interconnected with a powerful search interface. Availability and implementation SATORI is an open-source web application, which is freely available at http://satori.refinery-platform.org and integrated into the Refinery Platform. Contact nils@hms.harvard.edu. Supplementary information Supplementary data are available at Bioinformatics online.
A stereoselective total synthesis of (−)-rishitin

Abstract A new synthesis of (−)-rishitin (1) is reported, starting with chiral pool molecules. The crucial step is a stereoselective vinyl radical cyclization, which gives a 10:1 ratio of 21 to 22.
Radical dearomatization of arenes and heteroarenes

The stannane-mediated benzeneselenol-catalyzed addition of aryl iodides to a range of arenes and aromatic hetereocycles has been studied. With furan, thiophene, and several carbocyclic arenes, the addition takes place with quenching of the adduct radical by the catalytic selenol leading to moderate yields of aryl-dihydroarenes. With nitrogen heterocycles, on the other hand, it was not possible to suppress aromatization of the adduct radical and fully aromatized products were isolated. Aryl iodides bearing hydrogen bond donating groups in the ortho-position add to nitrogen heterocycles with high selectivity ortho- to the nitrogen, affording a simple one-step synthesis of potential chelating ligands. While 2-iodophenol is an excellent aryl radical source in these reactions, the homologous 1-iodo-2-naphthol fails owing to its reaction with diphenyl diselenide, which gives 1-phenylseleno-2-naphthol in high yield.
Platinum(II)-catalyzed 1,6-diene cycloisomerizations: Turnover in the absence of β-hydride elimination

Electrophilic pincer-ligated Pt(II)-dications are efficient catalysts for the cycloisomerization of 1,6-dienes, initiated by alkene activation. The tridentate ligands inhibit β-hydride elimination and thus enable cationic mechanisms that turnover by Pt(II) extrusion. PPP ligands lead to cyclopropane products, while PNP ligands provide cyclohexene products; mechanistic issues are also discussed.
Diastereoselective Additions of Chiral Vinylzinc Reagents to α-Chiral Aldehydes

Additions of vinylic zinc bromide reagents to α-chiral aldehydes (R1 = CH2OTBS, R2 = Me; R1 = Me, R2 = OTBS) in the presence of lithiated (+)- or (−)-N-methylephedrine proceed with predominant reagent control to afford anti or syn adducts stereoselectively, except when the aldehydes possess an alkoxy substituent at the α- or β-positions (R1 = Me, R2 = OBn; R1 = CH2OBn, R2 = Me), in which case chelation-controlled adducts predominate.
Blind Certificate Authorities

We explore how to build a blind certificate authority (CA). Unlike conventional CAs, which learn the exact identity of those registering a public key, a blind CA can simultaneously validate an identity and provide a certificate binding a public key to it, without ever learning the identity. Blind CAs would therefore allow bootstrapping truly anonymous systems in which no party ever learns who participates. In this work we focus on constructing blind CAs that can bind an email address to a public key. To do so, we first introduce secure channel injection (SCI) protocols. These allow one party (in our setting, the blind CA) to insert a private message into another party's encrypted communications. We construct an efficient SCI protocol for communications delivered over TLS, and use it to realize anonymous proofs of account ownership for SMTP servers. Combined with a zero-knowledge certificate signing protocol, we build the first blind CA that allows Alice to obtain a X.509 certificate binding her email address alice@domain.com to a public key of her choosing without ever revealing ``alice'' to the CA. We show experimentally that our system works with standard email server implementations as well as Gmail.
TFA-sensitive arylsulfonylthiourea-assisted synthesis of N, N'-substituted guanidines

An efficient synthesis of N,N‘-substituted guanidine derivatives was developed via an aromatic sulfonyl-activated thiourea intermediate. The use of certain aromatic sulfonamides, such as PbfNH2, as the key reagent to incorporate a TFA-labile guanidine protection group greatly facilitates solid-phase synthesis of N,N‘-substituted guanidine compounds.
Synthesis and Structure of Bismuth(III)-Containing Noncentrosymmetric Phosphates, Cs3KBi2M4(PO4)6Cl (M = Mn, Fe). Monoclinic (Cc) and Tetragonal (P43) Polymorphs Templated by Chlorine-Centered Cl(Bi2Cs) Acentric Units

Single crystals of three new noncentrosymmetric (NCS) phosphates, α (1) and β (2) forms of Cs3KBi2Mn4(PO4)6Cl and α-Cs3KBi2Fe4(PO4)6Cl (3), were grown in a reactive CsCl/KCl molten-salt media. Their structures were determined by single-crystal X-ray diffraction methods showing that the α form crystallizes in the space group Cc (No. 9), which is in one of the 10 NCS polar crystal classes, m (2/m) while the β form crystallizes in P43 (No. 78) of another polar class, 4 (4/m). The unit cell parameters of the α form can be approximately correlated with that of the β form via the 3 × 3 orientation matrix [0.5, 0.5, 0; −0.5, 0.5, 0; 0, 0, 2 sin β]. The structures of these otherwise complicated phosphates exhibit two types of channels with circular and elliptical windows where the Cl-centered Cl(Bi2Cs) acentric unit is located. The neighboring acentric units are arranged in a parallel fashion in the α form, resulting in the monoclinic (Cc) lattice, but “antiparallel” in the β form, thus giving the tetragonal (P43...
ADDRESSING THE UNUSUAL REACTIVITY OF 2-PYRIDINECARBOXALDEHYDE AND 2-QUINOLINECARBOXALDEHYDE IN BASE-CATALYZED ALDOL REACTIONS WITH ACETOPHENONE

Abstract 2-Pyridinecarboxaldehyde and 2-quinolinecarboxaldehyde undergo rapid, tandem aldol-Michael reactions with the lithium, sodium, and potassium enolates of acetophenone at room temperature to give high yields of 3-(2-pyridinyl)-1-phenyl-2-propenone and 3-(2-quinolyl)-1-phenyl-2-propenone, respectively. The aldol condensation product can be obtained in high yield when pyridine is added to the reaction mixture.
A ring expansion-annulation strategy for the synthesis of substituted azulenes. Preparation and Suzuki coupling reactions of 1-azulenyl triflates.

A new strategy for the synthesis of substituted azulenes is reported, based on the reaction of β‘-bromo-α-diazo ketones with rhodium carboxylates. The key transformation involves intramolecular addition of a rhodium carbenoid to an arene π-bond, electrocyclic ring opening, β-elimination, tautomerization, and trapping to produce 1-hydroxyazulene derivatives. The synthetic utility of the method is enhanced by the ability of the triflate derivatives to participate in Suzuki coupling reactions, as illustrated in a synthesis of the antiulcer drug egualen sodium (KT1-32).
A concise synthesis of the HIV-protease inhibitor nelfinavir via an unusual tetrahydrofuran rearrangement

Abstract An efficient synthesis of nelfinavir 1 was developed. The synthesis features an unusual rearrangement of a 3-amidotetrahydrofuran into a functionalized oxazoline.
Circuit Robustness to Temperature Perturbation Is Altered by Neuromodulators.

Summary In the ocean, the crab Cancer borealis is subject to daily and seasonal temperature changes. Previous work, done in the presence of descending modulatory inputs, had shown that the pyloric rhythm of the crab increases in frequency as temperature increases but maintains its characteristic phase relationships until it “crashes” at extremely high temperatures. To study the interaction between neuromodulators and temperature perturbations, we studied the effects of temperature on preparations from which the descending modulatory inputs were removed. Under these conditions, the pyloric rhythm was destabilized. We then studied the effects of temperature on preparations in the presence of oxotremorine, proctolin, and serotonin. Oxotremorine and proctolin enhanced the robustness of the pyloric rhythm, whereas serotonin made the rhythm less robust. These experiments reveal considerable animal-to-animal diversity in their crash stability, consistent with the interpretation that cryptic differences in many cell and network parameters are revealed by extreme perturbations.
Synthesis of polyheterocyclic ring compounds by the intramolecular cycloaddition of N-alkenyl substituted diazoimides

Abstract Rhodium(II) catalysis of various diazoimides containing tethered π-systems attached to the nitrogen atom results in isomunchnone dipole formation followed by intramolecular dipolar-cycloaddition.
REACTIONS OF 2,2',5',2 -TERFURAN

Formylation of 2,2′,5′,2′-terfuran (1) with N-methylformanilide and phosphorus oxychloride gave 5-formyl-2,2′,5′,2′-terfuran (2) and 5,5′-diformyl-2,2′5′,2′-terfuran (3). Reduction of 2 and 3 afforded 5-hydroxymethyl-2,2′,5′,2′-terfuran (4) and 5,5′ dihydroxymethyl-2,2′,5′,2′-terfuran (5), respectively. Terfuran 1 reacted with phenylmagnesium bromide to give 5-(phenylhydroxymethyl)-2,2′,5′,2′-terfuran (6), and was carbonated to 5-carboxy 2,2′,5′,2′-terfuran (7) and 5,5′-dicarboxy-2,2′,5′,2′-terfuran (8). Bromination of 1 with N-bromosuccinimide gave 5,5′-dibromo 2,2′,5′,2′-terfuran (9).
Stereochemical implications in the synthesis of 3,3′-spirocyclopropyl oxindoles from β-aryl/alkyl-substituted alkylidene oxindoles

Abstract 3,3′-Spirocyclopropane oxindoles were synthesized in good to excellent yield and diastereoselectivity employing a Kukhtin–Ramirez reaction between readily accessible E -alkylidene oxindoles, commercially available P(NMe 2 ) 3 , and α-keto esters. The stereoselectivity in the cyclopropanation event can be traced to the starting alkylidene geometry and the propensity of the exocyclic alkene to undergo isomerization in the presence of an electron rich phosphine.
Comprehensive characterization of neutrophil genome topology

Neutrophils are responsible for the first line of defense against invading pathogens. Their nuclei are uniquely structured as multiple lobes that establish a highly constrained nuclear environment. Here we found that neutrophil differentiation was not associated with large-scale changes in the number and sizes of topologically associating domains (TADs). However, neutrophil genomes were enriched for long-range genomic interactions that spanned multiple TADs. Population-based simulation of spherical and toroid genomes revealed declining radii of gyration for neutrophil chromosomes. We found that neutrophil genomes were highly enriched for heterochromatic genomic interactions across vast genomic distances, a process named supercontraction. Supercontraction involved genomic regions located in the heterochromatic compartment in both progenitors and neutrophils or genomic regions that switched from the euchromatic to the heterochromatic compartment during neutrophil differentiation. Supercontraction was accompanied by the repositioning of centromeres, pericentromeres, and long interspersed nuclear elements (LINEs) to the neutrophil nuclear lamina. We found that Lamin B receptor expression was required to attach centromeric and pericentromeric repeats but not LINE-1 elements to the lamina. Differentiating neutrophils also repositioned ribosomal DNA and mininucleoli to the lamina-a process that was closely associated with sharply reduced ribosomal RNA expression. We propose that large-scale chromatin reorganization involving supercontraction and recruitment of heterochromatin and nucleoli to the nuclear lamina facilitates the folding of the neutrophil genome into a confined geometry imposed by a multilobed nuclear architecture.
Preparation of nanocrystalline molybdenum disilicide (MoSi2) by a chlorine-transfer reaction

Reaction of MoCl3 and Si at 500 °C produces phase-pure MoSi2 powders in near-quantitative yields. Use of an inert diluent (LiCl or ZnCl2) enables the production of nanocrystalline powders. The diluent can be subsequently removed by washing with methanol or by sublimation. Consolidation of diluent-free powders by hot pressing at 1400 °C and 375 MPa for 0.5−4 h affords dense compacts (>95% theoretical density) possessing nanocrystalline grains (<50 nm) and exhibiting hardnesses of 15.0−16.3 GPa. This constitutes a 60−75% enhancement in hardness over conventional, microcrystalline MoSi2.
Analysis of Escherichia coli Flagellin Gene Expression in Simulated Spaceflight Growth Conditions

Population growth curves of Escherichia coli (E. coli) cultures propagated in spaceflight environments demonstrate an extended log phase duration and an increased final cell concentration compared to E. coli cultures grown on Earth. We suggest that during spaceflight, a lack of convective mixing in the growth medium alters a cell’s microenvironment such that the cell at first devotes its resources primarily to motility and later shifts most of its resources to reproduction. As flagellin is the major protein component of flagella, the motility structure of E. coli, we propose that the expression of the flagellin gene (fliC) can be used as a diagnostic marker for determining if the bacterium is in fact altering its allocation of cellular resources to motility during specific growth phases. We have used semiquantitative RT-PCR to analyze the expression of fliC in cultures grown in laboratory apparatus that simulate various aspects of the spaceflight environment. The data from this pilot study indicate that fliC expression increases initially under stationary, slow clinorotation, and fast clinorotation growth conditions, peaking at mid-exponential phase and decreasing dramatically in stationary phase. These data support the hypothesis that metabolic resources are being directed towards forming the flagellum, the bacteria motile structure, before shifting resources to growth, reproduction, and maintenance.
FFT and Swept Spectrum Analysis in Microwave Measurements

Accuracy, speed, and dynamic range are important considerations, among which tradeoffs are typically made for a given measurement. We present that FFT (fast Fourier transform) spectrum analysis is inherently less accurate than Swept Spectrum Analysis with a digital IF (intermediate frequency) section. For phase noise-like dynamic range considerations, we describe FFTs as having more noise than Swept Analysis. When speed is the driving factor we present FFTs as the technique of choice for narrow-band analysis, while swept analysis is substantially faster for wider bandwidths. Finally, a novel continuum between the performance of swept and FFT analysis is also presented.