cssi/SciSciGPT-SciSciNet huggingface dataset:
Lewis acid catalyzed rearrangement of furylcarbinols: The aza- and oxa-piancatelli cascade reaction

The acid-catalyzed rearrangement of furylcarbinols is utilized to access 4,5-substituted cyclopentenones. This cascade transformation began with implementing anilines, as an alternative nucleophile to water as used in the Piancatelli rearrangement, and has currently progressed through an intramolecular rearrangement to the use of alcohols as the nucleophile.
Photochemistry of alkenyl- and acetal-substituted pyridines

Ethyl 3-(2-pyridyl)propionate formation results from irradiation of 3-(2-pyridyl)propanal diethylacetal in acetonitrile. This photoreaction is unique to the heteroaromatic pyridine and only occurs in acetonitrile. A minor product, 1-aza-2-methyl-3-(2-ethanal diethylacetal)-4-ethoxycycloocta-1,3,5,7-tetraene, is also obtained. The irradiation of 2-methyl-6-(2-pyridyl)-2-pentene in the presence of various sensitizers results in addition to the alkene side-chain to produce oxetanes.
Synthesis of the 4-arylindole portion of the antitumor agent diazonamide and related studies

Abstract The synthesis of 6 comprising the CDG rings of the diazonamides was achieved in an overall yield of 75% from commercially available 3 .
Total synthesis of (+/-)-lennoxamine and (+/-)-aphanorphine by intramolecular electrophilic aromatic substitution reactions of 2-amidoacroleins.

Intramolecular electrophilic aromatic substitution reactions of 2-amidoacroleins constitute the key steps in the total syntheses of lennoxamine and aphanorphine. The aldehyde moiety of one cyclization product was transformed to a double bond, which was then engaged in a radical cyclization to produce the complete ring system of lennoxamine. The aldehyde functionality of the other cyclization product was converted to the corresponding mesylate, which underwent intramolecular displacement by a lactam enolate to furnish the ring system of aphanorphine.
AutoCryoPicker: an unsupervised learning approach for fully automated single particle picking in Cryo-EM images

An important task of macromolecular structure determination by cryo-electron microscopy (cryo-EM) is the identification of single particles in micrographs (particle picking). Due to the necessity of human involvement in the process, current particle picking techniques are time consuming and often result in many false positives and negatives. Adjusting the parameters to eliminate false positives often excludes true particles in certain orientations. The supervised machine learning (e.g. deep learning) methods for particle picking often need a large training dataset, which requires extensive manual annotation. Other reference-dependent methods rely on low-resolution templates for particle detection, matching and picking, and therefore, are not fully automated. These issues motivate us to develop a fully automated, unbiased framework for particle picking. We design a fully automated, unsupervised approach for single particle picking in cryo-EM micrographs. Our approach consists of three stages: image preprocessing, particle clustering, and particle picking. The image preprocessing is based on multiple techniques including: image averaging, normalization, cryo-EM image contrast enhancement correction (CEC), histogram equalization, restoration, adaptive histogram equalization, guided image filtering, and morphological operations. Image preprocessing significantly improves the quality of original cryo-EM images. Our particle clustering method is based on an intensity distribution model which is much faster and more accurate than traditional K-means and Fuzzy C-Means (FCM) algorithms for single particle clustering. Our particle picking method, based on image cleaning and shape detection with a modified Circular Hough Transform algorithm, effectively detects the shape and the center of each particle and creates a bounding box encapsulating the particles. AutoCryoPicker can automatically and effectively recognize particle-like objects from noisy cryo-EM micrographs without the need of labeled training data or human intervention making it a useful tool for cryo-EM protein structure determination.
Halogen-exchange reactions between alkyl fluorides and boron trihalides or titanium tetrahalides. A convenient synthesis of alkyl halides from alkyl fluorides

Abstract A simple and effective method for converting fluoroalkanes to their corresponding chloro-, bromo- and iodo-alkanes using commercially available boron trihalides and titanium tetrahalides is described.
RNA Binding Motif Protein 48 Is Required for U12 Splicing and Maize Endosperm Differentiation

The last eukaryotic common ancestor had two classes of introns that are still found in most eukaryotic lineages. Common U2-type and rare U12-type introns are spliced by the major and minor spliceosomes, respectively. Relatively few splicing factors have been shown to be specific to the minor spliceosome. We found that the maize (Zea mays) RNA binding motif protein 48 (RBM48) is a U12 splicing factor that functions to promote cell differentiation and repress cell proliferation. RBM48 is coselected with the U12 splicing factor, zinc finger CCCH-type, RNA binding motif, and Ser/Arg rich 2/Rough endosperm 3 (RGH3). Protein-protein interactions between RBM48, RGH3, and U2 Auxiliary Factor (U2AF) subunits suggest major and minor spliceosome factors required for intron recognition form complexes with RBM48. Human RBM48 interacts with armadillo repeat containing 7 (ARMC7). Maize RBM48 and ARMC7 have a conserved protein-protein interaction. These data predict that RBM48 is likely to function in U12 splicing throughout eukaryotes and that U12 splicing promotes endosperm cell differentiation in maize.
Phylogenomics reveals an extensive history of genome duplication in diatoms (Bacillariophyta).

Premise of the Study: Diatoms are one of the most species-rich lineages of microbial eukaryotes. Similarities in clade age, species richness, and primary productivity motivate comparisons to angiosperms, whose genomes have been inordinately shaped by whole-genome duplication (WGD). WGDs have been linked to speciation, increased rates of lineage diversification, and identified as a principal driver of angiosperm evolution. We synthesized a large but scattered body of evidence that suggests polyploidy may be common in diatoms as well. Methods: We used gene counts, gene trees, and distributions of synonymous divergence to carry out a phylogenomic analysis of WGD across a diverse set of 37 diatom species. Key Results: Several methods identified WGDs of varying age across diatoms. Determining the occurrence, exact number, and placement of events was greatly impacted by uncertainty in gene trees. WGDs inferred from synonymous divergence of paralogs varied depending on how redundancy in transcriptomes was assessed, gene families were assembled, and synonymous distances (Ks) were calculated. Our results highlighted a need for systematic evaluation of key methodological aspects of Ks-based approaches to WGD inference. Gene tree reconciliations supported allopolyploidy as the predominant mode of polyploid formation, with strong evidence for ancient allopolyploid events in the thalassiosiroid and pennate diatom clades. Conclusions: Our results suggest that WGD has played a major role in the evolution of diatom genomes. We outline challenges in reconstructing paleopolyploid events in diatoms that, together with these results, offer a framework for understanding the impact of genome duplication in a group that likely harbors substantial genomic diversity.
Sequential Regulation of Maternal mRNAs through a Conserved cis-Acting Element in Their 3' UTRs.

Summary Maternal mRNAs synthesized during oogenesis initiate the development of future generations. Some maternal mRNAs are either somatic or germline determinants and must be translationally repressed until embryogenesis. However, the translational repressors themselves are temporally regulated. We used polar granule component (pgc), a Drosophila maternal mRNA, to ask how maternal transcripts are repressed while the regulatory landscape is shifting. pgc, a germline determinant, is translationally regulated throughout oogenesis. We find that different conserved RNA-binding proteins bind a 10-nt sequence in the 3′ UTR of pgc mRNA to continuously repress translation at different stages of oogenesis. Pumilio binds to this sequence in undifferentiated and early-differentiating oocytes to block Pgc translation. After differentiation, Bruno levels increase, allowing Bruno to bind the same sequence and take over translational repression of pgc mRNA. We have identified a class of maternal mRNAs that are regulated similarly, including zelda, the activator of the zygotic genome.
A Stereochemical Probe of the Tetrahedral Intermediate in the Reactions of Acetyl-Coenzyme A Dependent Acetyltransferases

A pair of isomeric acetyl-coenzyme A (acetyl-CoA) analogs have been prepared in which the thioester group is replaced with a secondary alcohol. The two isomers differ in stereoconfiguration of the secondary alcohol and were designed to mimic the two possible configurations of the tetrahedral intermediate or transition state in the reactions of acetyl-CoA dependent acetyltransferases. These two isomers were tested as inhibitors of chloramphenicol acetyltransferase and carnitine acetyltransferase, both of which have previously been predicted to form a tetrahedral intermediate which matches the configuration of the (S)-alcohol. The (S)-isomer was the more potent inhibitor of both enzymes, with Ki values 12-fold and 6-fold lower than the Ki values for the (R)-isomer. The (S)-isomer was also the more potent inhibitor of phosphate acetyltransferase, acetyl-CoA synthetase, and arylamine acetyltransferase, for which the stereochemistry of the tetrahedral intermediate was previously unknown. These results suggest ...
Synthesis of Fe2–xMnxP Nanoparticles from Single-Source Molecular Precursors

The feasibility of preparing Fe2–xMnxP nanoparticles using the single-source precursors FeMn(CO)8(μ-PR2) (R = Ph or R = H) has been investigated. The solution-based thermal decomposition of FeMn(CO)8(μ-PPh2) in the presence of hexadecylamine and oleic acid resulted in the formation of FeO nanoparticles, while decomposition of FeMn(CO)8(μ-PH2) under similar conditions yielded iron-rich Fe2–xMnxP nanoparticles. Solventless decomposition of FeMn(CO)8(μ-PH2) at 573 K resulted in the formation of hexagonal FeMnP, a structure generally observed only at temperatures above 1473 K. The role of surface stabilizing agents in the production of iron-rich Fe2–xMnxP nanoparticles was examined through a series of experiments in which the type and quantity of stabilizers were varied, and evidence that oleic acid was responsible for the leaching or sequestration of manganese atoms was obtained. X-ray photoelectron spectroscopy (XPS) data acquired from the Fe2–xMnxP nanoparticles and powder X-ray diffraction (PXRD) data fro...
[Sc2(μ-OH)2(H2O)6(NO3)2](NO3)2: aqueous synthesis and characterization.

[Sc2(μ-OH)2(H2O)6(NO3)2](NO3)2 has been synthesized from an aqueous scandium nitrate solution by using zinc powder as a reducing agent for nitric acid, which drives an increase in pH and forces the condensation of aqua scandium cations. This preparative route readily produces gram-scale samples with yields near 65%. A single-crystal X-ray diffraction study reveals a structure characterized by a hydroxo-bridged Sc dimer. The FTIR spectrum of the compound has been modeled via ab initio computations, allowing the identification of signature IR peaks. Some initial observations on the thermal transformation of the compound to Sc2O3 are also reported.
Parvalbumin Loss Following Chronic Sub-Anesthetic NMDA Antagonist Treatment is Age-Dependent in the Hippocampus: Implications for Modeling NMDA Hypofunction.

Abstract A marked decrease in parvalbumin (PV), a calcium-binding protein specific to a subset of GABAergic neurons, is a consistent finding in postmortem schizophrenic brain tissue. This reduction is selective to PV and is regionally specific, occurring primarily in the prefrontal cortex and hippocampus (HPC) of patients. Rodent models of NMDA receptor hypofunction utilizing NMDA antagonist treatments – e.g. ketamine (KET) – show schizophrenia-like cognitive and behavioral impairments with parallel changes in PV. While decreased PV is considered a hallmark of neuropathology in schizophrenia, previous work elucidating the effects of KET administration on PV are contradictory, with findings suggesting decreased, increased, or no change in PV expression. Upon close examination of the procedures used across studies, there are two primary inconsistencies, including: (1) the age of animals used; and (2) the timeline of post-treatment tissue collection. To better understand whether these key differences impact observed PV changes, the present study investigated the impact of age and time of sacrifice on chronic KET-induced PV changes in the neocortex and HPC. Our findings suggest an effect of age, but not sacrifice timeline, on PV cell count following 14 days of sub-anesthetic KET treatment. We provide evidence that 1-month-old rats exhibit a significant KET-induced HPC PV decrease, while adult rats show a modest increase in HPC PV following chronic KET. Taken together, we propose that PV is a dynamic marker, and that changes in cell counts – and their interpretation – following NDMA antagonist treatment should be considered in the context of age.
Erroneous inference based on a lack of preference within one group: Autism, mice, and the social approach task

The Social Approach Task is commonly used to identify sociability deficits when modeling liability factors for autism spectrum disorder (ASD) in mice. It was developed to expand upon existing assays to examine distinct aspects of social behavior in rodents and has become a standard component of mouse ASD-relevant phenotyping pipelines. However, there is variability in the statistical analysis and interpretation of results from this task. A common analytical approach is to conduct within-group comparisons only, and then interpret a difference in significance levels as if it were a group difference, without any direct comparison. As an efficient shorthand, we named this approach EWOCs: Erroneous Within-group Only Comparisons. Here, we examined the prevalence of EWOCs and used simulations to test whether this approach could produce misleading inferences. Our review of Social Approach studies of high-confidence ASD genes revealed 45% of papers sampled used only this analytical approach. Through simulations, we then demonstrate how a lack of significant difference within one group often does not correspond to a significant difference between groups, and show this erroneous interpretation increases the rate of false positives up to 25%. Finally, we define a simple solution: use an index, like a social preference score, with direct statistical comparisons between groups to identify significant differences. We also provide power calculations to guide sample size in future studies. Overall, elimination of EWOCs and adoption of direct comparisons should result in more accurate, reliable, and reproducible data interpretations from the Social Approach Task across ASD liability models. Autism Res 2019, 12: 1171-1183. © 2019 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: The Social Approach Task is widely used to assess social behavior in mice and is frequently used in studies modeling autism. However, reviewing published studies showed nearly half do not use correct comparisons to interpret these data. Using simulated and original data, we argue the correct statistical approach is a direct comparison of scores between groups. This simple solution should reduce false positives and improve consistency of results across studies.
Shared and distinct transcriptomic cell types across neocortical areas

The neocortex contains a multitude of cell types that are segregated into layers and functionally distinct areas. To investigate the diversity of cell types across the mouse neocortex, here we analysed 23,822 cells from two areas at distant poles of the mouse neocortex: the primary visual cortex and the anterior lateral motor cortex. We define 133 transcriptomic cell types by deep, single-cell RNA sequencing. Nearly all types of GABA (γ-aminobutyric acid)-containing neurons are shared across both areas, whereas most types of glutamatergic neurons were found in one of the two areas. By combining single-cell RNA sequencing and retrograde labelling, we match transcriptomic types of glutamatergic neurons to their long-range projection specificity. Our study establishes a combined transcriptomic and projectional taxonomy of cortical cell types from functionally distinct areas of the adult mouse cortex.
Porphyrins with exocyclic rings. Part 21: Influence of pyrrolic and carbocyclic ring alkyl substituents on the synthesis of porphyrins bearing six-membered exocyclic rings

Abstract A series of 5-substituted 4,5,6,7-tetrahydroindoles were prepared by reacting 4-substituted cyclohexanones with phenylhydrazones derived from esters of acetoacetic acid under Knorr-type reaction conditions. Related 6,6-dimethyltetrahydroindoles were also prepared by reacting dimedone with oximes by the Knorr pyrrole syntheses, followed by selective reduction of the remaining ketone moiety with diborane. The substituted tetrahydroindoles were regioselectively oxidized with lead tetraacetate to give the related 7-acetoxy derivatives, and these reacted with 5-unsubstituted pyrrole esters to give pyrrolyltetrahydroindoles. In one case, a bromo substituent was used to protect the β-position of the pyrrole reactant. Cleavage of the benzyl ester protective groups with hydrogen over Pd/C, which also removes the bromo-protective group, gave four dipyrrole carboxylic acids. These were condensed with a dipyrrylmethane dialdehyde using the MacDonald ‘2+2’ condensation to give substituted porphyrins with six-membered exocyclic rings. These structures are useful for comparison to porphyrin samples found in organic-rich sediments such as oil shales and petroleum. The presence of methyl substituents on the six-membered ring for the tetrahydroindole precursors slightly decreases the yields for porphyrin synthesis, and this effect is enhanced when the system becomes more sterically crowded due to the presence of an ethyl group of the adjacent pyrrole ring. 5-Alkyl substituted tetrahydroindoles were also converted to tetrapropanoporphyrins via a cyclotetramerization procedure. The alkyl substituents again decreased the yields, although 5-alkyl substituents were found to have a far less deleterious effect than 6-alkyl groups. In addition to providing samples to help assign the vibrational spectra of geoporphyrin samples, these results demonstrate that highly substituted porphyrin systems can be prepared from tetrahydroindole derivatives.
Exploring the Chemistry of N,N′-Diamidocarbenes with Organophosphorus Compounds

A readily available N,N'-diamidocarbene (DAC) was found to insert into the P-H bonds of primary and secondary phosphines as well as a phosphonate ester. In contrast, tertiary phosphines catalyzed the ring contraction of the DAC to an iminopyrrolidinedione. Treating the DAC with trimethyl phosphite afforded the corresponding diamidophosphonate ester and olefinic products expected from an Arbuzov-type reaction.
The Role of Circle of Willis Anatomy Variations in Cardio-embolic Stroke: A Patient-Specific Simulation Based Study

We describe a patient-specific simulation based investigation on the role of Circle of Willis anatomy in cardioembolic stroke. Our simulation framework consists of medical image-driven modeling of patient anatomy including the Circle, 3D blood flow simulation through patient vasculature, embolus transport modeling using a discrete particle dynamics technique, and a sampling based approach to incorporate parametric variations. A total of 24 (four patients and six Circle anatomies including the complete Circle) models were considered, with cardiogenic emboli of varying sizes and compositions released virtually and tracked to compute distribution to the brain. The results establish that Circle anatomical variations significantly influence embolus distribution to the six major cerebral arteries. Embolus distribution to MCA territory is found to be least sensitive to the influence of anatomical variations. For varying Circle topologies, differences in flow through cervical vasculature are observed. This incoming flow is recruited differently across the communicating arteries of the Circle for varying anastomoses. Emboli interact with the routed flow, and can undergo significant traversal across the Circle arterial segments, depending upon their inertia and density ratio with respect to blood. This interaction drives the underlying biomechanics of embolus transport across the Circle, explaining how Circle anatomy influences embolism risk.
An indium-promoted alternative to the Knoevenagel condensation of aldehydes with methyl acetoacetate

Abstract Addition of methyl (E)-4-bromo-3-methoxycrotonate to aldehydes in the presence of indium and water delivers β-hydroxy esters, acidic hydrolysis of which leads to Knoevenagel-like adducts.
Synthesis of Furocoumarins and Biscoumarins by an Isocyanide-Induced Multicomponent Reaction: Isocyanide as a Masked Amine:

The three-component reaction involving chromone-3-carbaldehyde, 4-hydroxycoumarin and cyclohexyl isocyanide produces furocoumarin and biscoumarin derivatives. Formation of the latter compound seems...
Rhodium perfluorobutyramide (Rh2(pfm)4 ) : a synthetically useful catalyst for olefin aziridinations

Abstract Rhodium perfluorobutyramide (Rh 2 (pfm) 4 ) has been shown to catalyze the conversion of olefins to trichloroethoxysulfonyl, nosyl, and tosyl aziridines. Advantages of this aziridination procedure include the microwave-assisted preparation of the catalyst and the practical use of the alkene substrate as the limiting reagent.
Thiocyanogen as an intermediate in the oxidation of thiocyanate by hydrogen peroxide in acidic aqueous solution.

The kinetics of the reaction of H2O2 with excess SCN- in acidic media was studied by use of Ti(IV) as an indicator for the concentration of H2O2. Pseudo-first-order behavior was realized by this method, and these data confirm the acid-catalyzed rate law and rate constant reported some 40 years ago for this reaction under conditions of excess H2O2. Under the same conditions except without Ti(IV), repetitive-scan spectra reveal the formation and decay of an intermediate that absorbs in the UV. In the proposed mechanism, HOSCN is produced in the first step and it is converted rapidly to (SCN)2 through its equilibrium reaction with SCN-. The observed intermediate is believed to be (SCN)2, which decays on a longer time scale. Excellent global fits of this mechanism to the repetitive-scan data are obtained with rate constants constrained by the Ti(IV) data and published previously in our study of the ClO2/SCN- reaction. These fits yield a spectrum for (SCN)2 that is characterized by λmax = 297 nm and e297 = 147...
Synthesis of 2,4-Disubstituted Pyrroles by Rearrangements of 2-Furanyl Carbamates

2,4-Disubstituted pyrroles were synthesized by an oxidative rearrangement of a furanyl carbamate followed by sequential reaction of the resulting 5-methoxypyrrol-2(5H)-one with different alkyl lithiates. The final step of the procedure involves heating the ring opened 1-methoxy-5-oxopentylcarbamate with a primary amine.
Multiple Component Reactions: An Efficient Nickel-Catalyzed Reformatsky-Type Reaction and Its Application in the Parallel Synthesis of β-Amino Carbonyl Libraries

Multiple-component condensations (MCC) where three or more reactants combine to afford a new core structure possessing the molecular features of its composite building blocks is a powerful method for the preparation of molecular diversity. We have developed an efficient, nickel-catalyzed, Reformatsky-type three-component condensation (3CC) reaction that affords β-amino carbonyl compounds. The scope of the reaction is demonstrated both in the gram and microscale settings; 15 β-amino esters, amides, and a ketone were prepared efficiently at the mmol scale, and a library of 64 β-amino carbonyl compounds was generated at the μmol scale.
Structure and Bonding in Yb4MgGe4: Yb2+/Yb3+ Mixed-Valency and Charge Separation

Reported are the synthesis and the structural characterization of a new derivative of the RE5Tt4 family (RE = Rare-earth; Tt = Tetrel, = Si, Ge, i.e., group 14 element), Yb5-xMgxGe4 (x ≈ 1). Crystal data for Yb4.04(1)Mg0.96(1)Ge4 at 23 °C: orthorhombic, space group Pnma (No. 62), Z = 4; a = 7.155(2) A, b = 14.769(5) A, c = 7.688(2) A; V = 812.5(4) A3. This phase is an example of a substitution of lanthanide metal (Yb) with a nonmagnetic element (Mg) within this structure type. Its structure can alternatively be described as an intergrowth of the hypothetical Yb2MgGe2, which features flat infinite [MgGe2]4- layers and the hypothetical YbGe with [Ge2]6- dimers. The flat [MgGe2]4- layers propagate in two dimensions (a and c), and they are offset by a distance of 1/4·a with respect to one another and are interspaced with layers of [Ge2]6- dimers and Yb cations filling the space between them. According to the structural and physical property data, Yb4MgGe4 is a heterogeneous mixed-valent compound, i.e. a syst...
A mild and efficient one-step synthesis of quinolines

2-Aminoaryl ketones undergo condensation with α-methylene ketones in the presence of a catalytic amount of Y(OTf)3 at room temperature under mild conditions to afford the corresponding polysubstituted quinolines in excellent yields.
High turnover number and rapid, room-temperature amination of chloroarenes using saturated carbene ligands.

A catalytic system for the mild amination of aryl chlorides is described. This system consists of a Pd(0) precursor and a dihydroimidazoline carbene ligand, which is generated in situ from its protonated tetrafluoroborate salt (2). Using this catalyst, aryl and heteroaryl chlorides react with secondary amines and anilines within hours at room temperature. Turnover numbers as high as 5000 are obtained at elevated temperatures for reaction of morpholine with an unactivated aryl chloride.
Synthesis of 1,2,3,12a,12b-Hexahydrocyclopropa-[1,2-d]benzo[f]pyrrolo[1,2-b]isoquinolin-5,7-dione related to duocarmycins and anthramycin

Structural features of the Duocarmycins and Anthramycin were incorporated into 1,2,3,12a,12b-hexahydro-cyclopropa[1,2-d]benzo[f]pyrrolo[1,2-b]isoquinolin 5,7-dione. The synthesis of the cis and trans diastereomers was accomplished using a benzyne Diels-Alder reaction and an imine-anhydride cyclization as key steps.
DAZL Regulates Germ Cell Survival through a Network of PolyA-Proximal mRNA Interactions.

Summary The RNA binding protein DAZL is essential for gametogenesis, but its direct in vivo functions, RNA targets, and the molecular basis for germ cell loss in Dazl-null mice are unknown. Here, we mapped transcriptome-wide DAZL-RNA interactions in vivo, revealing DAZL binding to thousands of mRNAs via polyA-proximal 3′ UTR interactions. In parallel, fluorescence-activated cell sorting and RNA-seq identified mRNAs sensitive to DAZL deletion in male germ cells. Despite binding a broad set of mRNAs, integrative analyses indicate that DAZL post-transcriptionally controls only a subset of its mRNA targets, namely those corresponding to a network of genes that are critical for germ cell proliferation and survival. In addition, we provide evidence that polyA sequences have key roles in specifying DAZL-RNA interactions across the transcriptome. Our results reveal a mechanism for DAZL-RNA binding and illustrate that DAZL functions as a master regulator of a post-transcriptional mRNA program essential for germ cell survival.
Intramolecular Diels-Alder reactions of 4-vinylimidazoles.

The synthesis of a variety of unsaturated ethers, esters, and amides derived from urocanic acid and their Diels−Alder reactions are reported. Propargylic ethers and esters cyclize with reasonable efficiencies, but the related mono- and unactivated olefins did not cyclize. On the other hand, the corresponding amines and amides, along with the doubly activated ester/amide derivatives participate in the cycloaddition reaction.
Spectra and Reactivity of Methoxyoligothiophene Cation Radicals

A set of α-coupled oligothiophenes, dimer through hexamer, was studied. Each oligomer was terminated with two methyl groups and was substituted with two or four methoxy groups. Electrochemical stud...
Hydrosilylation of aldehydes and ketones catalyzed by [Ph3P(CuH)]6

Abstract Exposure of an aldehyde or ketone to ≤5 mol% (in copper) of Stryker's reagent [Ph 3 P(CuH)] 6 in the presence of one of several silanes affords the corresponding protected alcohol in high yields. Aldehydes can be cleanly reduced in the presence of ketones.
Optical Properties of GaAs Confined in the Pores of MCM-41

We report on GaAs/MCM-41 heterostructures synthesized by deposition of GaAs into the channels of MCM-41 using metalloorganic chemical vapor deposition. MCM-41 consists of an ordered array of silica tubules comprising pores with uniform and controllable diameter in the nanometer range. The GaAs/MCM-41 heterostructures show blue-shifted absorption and broad visible photoluminescence even at room temperature. The photoluminescence maximum depends on the MCM-41 pore diameter supporting formation of size-quantized semiconductor crystallites whose growth is restricted by the diameter of the pores of MCM-41. The shift in the photoluminescence spectra as a function of the excitation wavelength suggests a broad size distribution of the GaAs particles crystallized on the outside of MCM-41 and a relatively narrow size distribution of the GaAs particles inside the channels of MCM-41.
Electron Withdrawing Substituents on Equatorial and Apical Phosphines Have Opposite Effects on the Regioselectivity of Rhodium Catalyzed Hydroformylation

The electronic effects of electron withdrawing aryl substituents on equatorial and apical diphosphines were investigated. Chelating diphosphines designed to coordinate in diequatorial or in apical−equatorial positions were synthesized, and their effects on the regioselectivity of rhodium catalyzed 1-hexene hydroformylation were observed. Only diequatorial coordination was observed for 2,2‘-bis[(diphenylphosphino)methyl]-1,1‘-biphenyl (BISBI) complexes (BISBI)Ir(CO)2H (8) and [BISBI-(3,5-CF3)]Ir(CO)2H (10), and only apical−equatorial coordination was seen for 1,2-bis(diphenylphosphino)ethane (DIPHOS) complexes (DIPHOS)Ir(CO)2H (14) and [DIPHOS-(3,5-CF3)]Ir(CO)2H (15). For the trans-1,2-bis[(diphenylphosphino)methyl]cyclopropane (T-BDCP) complexes, a mixture of diequatorial and apical−equatorial complexes was seen. For (T-BDCP)Ir(CO)2H (12), 12-ae was favored over 12-ee by 63:37, but for [T-BDCP-(3,5-CF3)]Ir(CO)2H (13) the conformational preference was reversed and a 10:90 ratio of 13-ae:13-ee was seen. The...
Place-Based Drivers of Mortality: Evidence from Migration

We estimate the effect of current location on elderly mortality by analyzing outcomes of movers in the Medicare population. We control for movers' origin locations as well as a rich vector of pre-move health measures. We also develop a novel strategy to adjust for remaining unobservables, using the correlation of residual mortality with movers' origins to gauge the importance of omitted variables. We estimate substantial effects of current location. Moving from a tenth to a ninetieth percentile location would increase life expectancy at age 65 by 1.1 years, and equalizing location effects would reduce cross-sectional variation in life expectancy by 15 percent. Places with favorable life expectancy effects tend to have higher quality and quantity of health care, less extreme climates, lower crime rates, and higher socioeconomic status.
Synthesis and 1H NMR spectra of some 1‐aryl‐2,5‐pyrrolidinediones

Three 1-aryl-2,5 pyrrolidinediones, two of which are novel, were prepared by reaction of the requisite primary aromatic amines with succinic anhydride, followed by treatment with acetic anhydride. The 1H nmr spectra for the derivatives in which aryl is 1-naphthyl and 1-anthracenyl exhibit 32-line multiplets for the four aliphatic hydrogens, indicating that all four are in different environments. Examination of molecular models demonstrates that the pyrrolidinedione and aryl ring systems cannot be coplanar and that rotation about the nitrogen-aryl bond is restricted. Molecular mechanics calculations reveal that a dihedral angle of 50–65° for the two ring systems results in the minimum steric interaction energy.
Tin(II) chloride dihydrate: A mild and efficient reagent for cleaving acetals.

Abstract Tin(II) chloride dihydrate (SnCl2·2H2O) efficiently converts conjugated dioxolones, and both dimethoxy and diethoxy acetals to aldehydes (84–98%). Similarly, nonconjugated dimethoxy and diethoxy acetals are also efficiently converted to aldehydes (84–94%). Conjugated pyrans and nonconjugated dioxolanes, however, are only converted to aldehydes in 17–38% yields.
Medicare Annual Wellness Visits: A Scoping Review of Current Practice Models and Opportunities for Pharmacists.

Objective:To explore the existing practice models and practice opportunities surrounding pharmacist-delivered Medicare Annual Wellness Visits (AWVs), with the goal of improving patient access throu...
Optimal Learning Algorithms for Stochastic Inventory Systems with Random Capacities

We propose the first learning algorithm for single‐product, periodic‐review, backlogging inventory systems with random production capacity. Different than the existing literature on this class of problems, we assume that the firm has neither prior information about the demand distribution nor the capacity distribution, and only has access to past demand and supply realizations. The supply realizations are censored capacity realizations in periods where the policy need not produce full capacity to reach its target inventory levels. If both the demand and capacity distributions were known at the beginning of the planning horizon, the well‐known target interval policies would be optimal, and the corresponding optimal cost is referred to as the clairvoyant optimal cost. When such distributional information is not available a priori to the firm, we propose a cyclic stochastic gradient descent type of algorithm whose running average cost asymptotically converges to the clairvoyant optimal cost. We prove that the rate of convergence guarantee of our algorithm is O(1/T), which is provably tight for this class of problems. We also conduct numerical experiments to demonstrate the effectiveness of our proposed algorithms.
Predictive Effects of Novelty Measured by Temporal Embeddings on the Growth of Scientific Literature

Novel scientiﬁc knowledge is constantly produced by the scientiﬁc community. Understanding the level of novelty characterized by scientiﬁc literature is key for modeling scientiﬁc dynamics and analyzing the growth mechanisms of scientiﬁc knowledge. Metrics derived from bibliometrics and citation analysis were effectively used to characterize the novelty in scientiﬁc development. However, time is required before we can observe links between documents such as citation links or patterns derived from the links, which makes these techniques more effective for retrospective analysis than predictive analysis. In this study, we present a new approach to measuring the novelty of a research topic in a scientiﬁc community over a speciﬁc period by tracking semantic changes of the terms and characterizing the research topic in their usage context. The semantic changes are derived from the text data of scientiﬁc literature by temporal embedding learning techniques. We validated the effects of the proposed novelty metric on predicting the future growth of scientiﬁc publications and investigated the relations between novelty and growth by panel data analysis applied in a large-scale publication dataset (MEDLINE/PubMed). Key ﬁndings based on the statistical investigation indicate that the novelty metric has signiﬁcant predictive effects on the growth of scientiﬁc literature and the predictive effects may last for more than ten years. We demonstrated the effectiveness and practical implications of the novelty metric in three case studies.
The Structure and Evolution of an Offline Peer-to-Peer Financial Network.

In this work, we investigate the structure and evolution of Venmo, one of the most popular peer-to-peer (P2P) mobile payment applications. A unique aspect of the network under consideration is that the edges among nodes represent financial transactions between individuals who shared an offline social interaction. We present a series of static and dynamic measurements that summarize the key aspects of any social network, namely the degree distribution, density, and connectivity. We find that the degree distributions do not follow a power-law distribution. With regards to density and connectivity, Venmo’s network exhibits densification and resilience, which indicate a high level of engagement from its users. Last, we examine the “topological” version of the small-world hypothesis, and find that Venmo users are separated by a mean of 5.9 steps and a median of 6 steps.
Interpolating convex and non-convex tensor decompositions via the subspace norm

We consider the problem of recovering a low-rank tensor from its noisy observation. Previous work has shown a recovery guarantee with signal to noise ratio O(n[K/2]/2) for recovering a Kth order rank one tensor of size n x · · · x n by recursive unfolding. In this paper, we first improve this bound to O(nK/4) by a much simpler approach, but with a more careful analysis. Then we propose a new norm called the subspace norm, which is based on the Kronecker products of factors obtained by the proposed simple estimator. The imposed Kronecker structure allows us to show a nearly ideal O(√n + √HK-1) bound, in which the parameter H controls the blend from the non-convex estimator to mode-wise nuclear norm minimization. Furthermore, we empirically demonstrate that the subspace norm achieves the nearly ideal denoising performance even with H = O(1).
Pseudo-Edge Unfoldings of Convex Polyhedra

A pseudo-edge graph of a convex polyhedron K is a 3-connected embedded graph in K whose vertices coincide with those of K, whose edges are distance minimizing geodesics, and whose faces are convex. We construct a convex polyhedron K in Euclidean 3-space with a pseudo-edge graph with respect to which K is not unfoldable. The proof is based on a result of Pogorelov on convex caps with prescribed curvature, and an unfoldability obstruction for almost flat convex caps due to Tarasov. Our example, which has 340 vertices, significantly simplifies an earlier construction by Tarasov, and confirms that Durer’s conjecture does not hold for pseudo-edge unfoldings.
Fourier-Sparse Interpolation without a Frequency Gap

We consider the problem of estimating a Fourier-sparse signal from noisy samples, where the sampling is done over some interval [0, T] and the frequencies can be "off-grid". Previous methods for this problem required the gap between frequencies to be above 1/T, the threshold required to robustly identify individual frequencies. We show the frequency gap is not necessary to estimate the signal as a whole: for arbitrary k-Fourier-sparse signals under l2 bounded noise, we show how to estimate the signal with a constant factor growth of the noise and sample complexity polynomial in k and logarithmic in the bandwidth and signal-to-noise ratio. As a special case, we get an algorithm to interpolate degree d polynomials from noisy measurements, using O(d) samples and increasing the noise by a constant factor in l2.
M2: Malleable Metal as a Service

Existing bare-metal cloud services that provide users with physical servers have a number of serious disadvantages over their virtual alternatives, including slow provisioning times, difficulty for users to release servers (physical machines) and then reuse them to handle changes in demand, and poor tolerance to failures. We introduce M2, a bare-metal cloud service that uses network-mounted boot drives to overcome these disadvantages. We describe the architecture and implementation of M2 and compare its agility, scalability and performance to existing systems. We show that M2 can reduce provisioning time by over 50% while offering richer functionality, and comparable run time performance with respect to tools that provision images into local disks. M2 is open source and available at https://github.com/CCI-MOC/ims.
Killing forms of isotropic Lie algebras

Abstract This paper presents a method for computing the Killing form of an isotropic Lie algebra defined over an arbitrary field based on the Killing form of a subalgebra containing its anisotropic kernel. This approach allows for streamlined formulas for many Lie algebras of types E 6 and E 7 and yields a unified formula for all Lie algebras of inner type E 6 , including the anisotropic ones.
Sending a Message with Unknown Noise

Alice and Bob are connected via a two-way channel, and Alice wants to send a message of L bits to Bob. An adversary flips an arbitrary but finite number of bits, T, on the channel. This adversary knows our algorithm and Alice's message, but does not know any private random bits generated by Alice or Bob, nor the bits sent over the channel, except when these bits can be predicted by knowledge of Alice's message or our algorithm. We want Bob to receive Alice's message and for both players to terminate, with error probability at most δ > 0, where δ is a parameter known to both Alice and Bob. Unfortunately, the value T is unknown in advance to either Alice or Bob, and the value L is unknown in advance to Bob.We describe an algorithm to solve the above problem while sending an expected L + O(T + min(T + 1, L /log L) log (L /δ)) bits. A special case is when δ = O (1/LC), for some constant c. Then when T = o (L /log L), the expected number of bits sent is L + o(L), and when T = Ω(L), the expected number of bits sent is L + O (T), which is asymptotically optimal.
Element-wise uniqueness, prior knowledge, and data-dependent resolution

Techniques for finding regularized solutions to underdetermined linear systems can be viewed as imposing prior knowledge on the unknown vector. The success of modern techniques, which can impose priors such as sparsity and non-negativity, is the result of advances in optimization algorithms to solve problems which lack closed-form solutions. Techniques for characterization and analysis of the system to determine when information is recoverable, however, still typically rely on closed-form solution techniques such as singular value decomposition or a filter cutoff estimate. In this letter we propose optimization approaches to broaden the approach to system characterization. We start by deriving conditions for when each unknown element of a system admits a unique solution, subject to a broad class of types of prior knowledge. With this approach we can pose a convex optimization problem to find “how unique” each element of the solution is, which may be viewed as a generalization of resolution to incorporate prior knowledge. We find that the result varies with the unknown vector itself, i.e., it is data-dependent, such as when the sparsity of the solution improves the chance it can be uniquely reconstructed. The approach can be used to analyze systems on a case-by-case basis, estimate the amount of important information present in the data, and quantitatively understand the degree to which the regularized solution may be trusted.
Linear Queries Estimation with Local Differential Privacy

We study the problem of estimating a set of d linear queries with respect to some unknown distribution p over a domain [J] based on a sensitive data set of n individuals under the constraint of local differential privacy. This problem subsumes a wide range of estimation tasks, e.g., distribution estimation and d-dimensional mean estimation. We provide new algorithms for both the offline (non-adaptive) and adaptive versions of this problem. In the offline setting, the set of queries are fixed before the algorithm starts. In the regime where n < d^2/\log(J), our algorithms attain L_2 estimation error that is independent of d. For the special case of distribution estimation, we show that projecting the output estimate of an algorithm due to [Acharya et al. 2018] on the probability simplex yields an L_2 error that depends only sub-logarithmically on J in the regime where n < J^2/\log(J). Our bounds are within a factor of at most (\log(J))^{1/4} from the optimal L_2 error. These results show the possibility of accurate estimation of linear queries in the high-dimensional settings under the L_2 error criterion. In the adaptive setting, the queries are generated over d rounds; one query at a time. In each round, a query can be chosen adaptively based on all the history of previous queries and answers. We give an algorithm for this problem with optimal L_{\infty} estimation error (worst error in the estimated values for the queries w.r.t. the data distribution). Our bound matches a lower bound on the L_{\infty} error in the offline version of this problem [Duchi et al. 2013].
Intelligently Assisting Human-Guided Quadcopter Photography.

Drones are a versatile platform for both amateur and professional photographers, enabling them to capture photos that are impossible to shoot with ground-based cameras. However, when guided by inexperienced pilots, they have a high incidence of collisions, crashes, and poorly framed photographs. This paper presents an intelligent user interface for photographing objects that is robust against navigation errors and reliably collects high quality photographs. By retaining the human in the loop, our system is faster and more selective than purely autonomous UAVs that employ simple coverage algorithms. The intelligent user interface operates in multiple modes, allowing the user to either directly control the quadcopter or fly in a semi-autonomous mode around a target object in the environment. To evaluate the interface, users completed a data set collection task in which they were asked to photograph objects from multiple views. Our sketchbased control paradigm facilitated task completion, reduced crashes, and was favorably reviewed by the participants.
Flattenings and Koszul Young flattenings arising in complexity theory

ABSTRACTI find new equations for Chow varieties, their secant varieties, and an additional variety that arises in the study of complexity theory by flattenings and Koszul Young flattenings. This enables a new lower bound for symmetric border rank of x1x2⋯xd when d is odd, and a new lower complexity bound for the permanent.
ObliviSync: Practical Oblivious File Backup and Synchronization

Oblivious RAM (ORAM) protocols are powerful techniques that hide a client's data as well as access patterns from untrusted service providers. We present an oblivious cloud storage system, ObliviSync, that specifically targets one of the most widely-used personal cloud storage paradigms: synchronization and backup services, popular examples of which are Dropbox, iCloud Drive, and Google Drive. This setting provides a unique opportunity because the above privacy properties can be achieved with a simpler form of ORAM called write-only ORAM, which allows for dramatically increased efficiency compared to related work. Our solution is asymptotically optimal and practically efficient, with a small constant overhead of approximately 4x compared with non-private file storage, depending only on the total data size and parameters chosen according to the usage rate, and not on the number or size of individual files. Our construction also offers protection against timing-channel attacks, which has not been previously considered in ORAM protocols. We built and evaluated a full implementation of ObliviSync that supports multiple simultaneous read-only clients and a single concurrent read/write client whose edits automatically and seamlessly propagate to the readers. We show that our system functions under high work loads, with realistic file size distributions, and with small additional latency (as compared to a baseline encrypted file system) when paired with Dropbox as the synchronization service.