cssi/SciSciGPT-SciSciNet huggingface dataset:
Robust Look-ahead Three-phase Balancing of Uncertain Distribution Loads

Increasing penetration of highly variable components such as solar generation and electric vehicle charging loads pose significant challenges to keeping three-phase loads balanced in modern distribution systems. Failure to maintain balance across three phases would lead to asset deterioration and increasing delivery losses. Motivated by the real-world needs to automate and optimize the three-phase balancing decision making, this paper introduces a robust look-ahead optimization framework that pursues balanced phases in the presence of demand-side uncertainties. We show that look-ahead moving window optimization can reduce imbalances among phases at the cost of a limited number of phase swapping operations. Case studies quantify the improvements of the proposed methods compared with conventional deterministic phase balancing. Discussions on possible benefits of the proposed methods and extensions are presented.
Jury diversity in the age of mass incarceration: an exploratory mock jury experiment examining felon-jurors’ potential impacts on deliberations

Today, nineteen million American citizens bear the mark of a felony conviction, far more than in any prior era. With that mark comes a host of record-based restrictions that curtail access to vario...
How Do States Implement College- and Career-Readiness Standards? A Distributed Leadership Analysis of Standards-Based Reform:

Purpose: Our primary purpose is to examine the implementation of college- and- career- readiness content standards in Kentucky, Ohio, and Texas through the lens of distributed leadership theory, an...
Three applications of delooping to h-principles

In this paper we give three applications of a method to prove h-principles on closed manifolds. Under weaker conditions this method proves a homological h-principle, under stronger conditions it proves a homotopical one. The three applications are as follows: a homotopical version of Vassiliev’s h-principle, the contractibility of the space of framed functions, and a version of Mather–Thurston theory.
Vibrational Signatures of Carboxylated Graphene: A First-Principles Study

Raman and infrared (IR) spectroscopies are fast, efficient, and nondestructive techniques commonly used for structural characterization of nanoscale materials. The complimentary characters of the Raman and IR spectroscopies make them ideally suited for experimental studies of carbon nanostructures. Using first-principles computational methods based on density functional perturbation theory, we computed nonresonant Raman and IR absorption spectra of carboxylated graphene containing no surface defects, containing Stone–Wales defects, and containing divacancies. Our calculations demonstrated that the presence of point defects near the functionalization sites significantly altered the Raman and IR spectra of carboxylated graphene. In all cases, we observed the emergence of new Raman and IR absorption bands in the range of low and high vibration frequencies. The calculated Raman and IR spectra showed clearly distinguishable spectroscopic signatures associated to different types of structural defects present in...
Bentham, Not Epicurus: The Relevance of Pleasure to Studies of Drug-Involved Pain:

There is a disproportionate focus on pain over pleasure in policy-relevant research on drugs. This is unfortunate because theories of and findings on drug-involved pleasure can be used to inform kn...
Clarifying the overlap between motivation and negative symptom measures in schizophrenia research: A meta-analysis.

Abstract Motivation and negative symptom research has recently been hampered by a series of inconsistent findings, leading to calls for a greater consensus on the type of measures used across studies. To inform this issue, we conducted a meta-analysis that quantified the association between motivation measures (self-report, performance-based) and clinician-rated negative symptom measures as well as a series of moderator analyses to develop a greater understanding of the measurement factors impacting this relationship. Forty-seven eligible studies with people with schizophrenia-spectrum disorders were included. Using a random-effects meta-analytic model, a small but significant overall effect size emerged between motivation and clinician-rated negative symptoms (r = −0.18). Several significant moderators were identified, including the generation of negative symptom measures such that there was a significantly stronger relationship between motivation and second-generation (r = −0.38) than first-generation negative symptom measures (r = −0.17). Further, the type of performance-based measure used moderated the relationship, with effort discounting tasks most strongly related to negative symptoms (r = −0.44). The domain of motivation assessed (intrinsic, extrinsic, amotivation) also moderated the relationship. These findings help to identify sources of inconsistencies observed in prior studies and point to both second-generation and effort discounting tasks as the most promising types of measures, particularly for those interested in validating motivation measures or assessing the effectiveness of motivation treatments. Although additional research is needed, our results suggest that using these measures may help to reduce inconsistencies across studies and move the field forward.
ADOLESCENT VIDEO GAME PLAYING AND FIGHTING OVER THE LONG‐TERM

I present new evidence of the link between video game play and fighting. The General Learning Model predicts that increased aggression from playing violent video games. These predictions are tested using a large longitudinal data set tracking adolescents over time. Consistent with previous research, there is a positive raw correlation between video game playing as an adolescent and aggressive outcomes, in this case fights, even more than a decade later. However, multivariate and instrumental variables estimators do not find a causal relationship. Some implications are: support policy for further interventions is undermined, future research should be more careful about identification threats, and similar methodological approaches can be applied to the effects of other new communication technologies. (JEL D18, L86, O35)
Incentive and dopamine sensitization produced by intermittent but not long access cocaine self‐administration

The temporal pattern of drug use (pharmacokinetics) has a profound effect on the ability of self-administered cocaine to produce addiction-like behavior in rodents, and to change the brain. To further address this issue, we compared the effects of long access (LgA) cocaine self-administration, which is widely used to model the transition to addiction, with intermittent access (IntA), which is thought to better reflect the pattern of drug use in humans, on the ability of a single, self-administered injection of cocaine to increase dopamine (DA) overflow in the core of the nucleus accumbens (using in vivo microdialysis), and to produce addiction-like behavior. IntA experience was more effective than LgA in producing addiction-like behavior-a drug experience-dependent increase in motivation for cocaine assessed using behavioral economic procedures, and cue-induced reinstatement-despite much less total drug consumption. There were no group differences in basal levels of DA in dialysate [DA], but a single self-administered IV injection of cocaine increased [DA] in the core of the nucleus accumbens to a greater extent in rats with prior IntA experience than those with LgA or limited access experience, and the latter two groups did not differ. Furthermore, high motivation for cocaine was associated with a high [DA] response. Thus, IntA, but not LgA, produced both incentive and DA sensitization. This is consistent with the notion that a hyper-responsive dopaminergic system may contribute to the transition from casual patterns of drug use to the problematic patterns that define addiction.
Digital Data, Platforms and the Usual [Antitrust] Suspects: Network Effects, Switching Costs, Essential Facility

This paper asks whether the large amounts of digital data that are typically observed on large technology platforms—such as Google, Facebook, Uber and Amazon—typically give rise to structural conditions that would lead to antitrust concerns. In particular, I evaluate whether digital data augments or decreases concerns with regard to network effects and switching costs. I also evaluate whether data should be thought of as an ‘essential facility’.
Markov Chain Monte Carlo Item Response Theory Estimation

Item response theory (IRT) is the cornerstone of modern measurement. The benefits of using IRT have been well documented. In order to use IRT models, it is necessary to estimate item parameters. As assessments become more complex, more sophisticated models need to be developed. The difficulty in making models more complex is the issue of parameter estimation, and, without the ability to estimate parameters, the models are not useful. With the growth of computer technology, new estimation techniques are being developed for IRT. One such technique is Markov Chain Monte Carlo (MCMC). MCMC provides parameter estimates by simulating draws from the posterior distribution of the parameters, and uses the constructed samples to provide point estimates of the parameters (e.g., means, modes). Both Gibbs sampling and Metropolis–Hastings within Gibbs are described, and examples of estimating parameters of dichotomous IRT models are provided. Keywords: Markov Chain Monte Carlo; Gibbs sampling; Metropolis–Hastings
NOMA for VLC Downlink Transmission With Random Receiver Orientation

Visible light communications (VLC) is an emerging technology with a promise of viable solution to spectrum crunch problem in conventional radio-frequency (RF) bands. In this paper, we consider a downlink multiuser VLC network where users randomly change their location and vertical orientation. In order to increase the spectral efficiency, we consider the non-orthogonal multiple access (NOMA) transmission to serve multiple users simultaneously. In particular, we propose individual and group-based user ordering techniques for NOMA with various user feedback schemes. In order to reduce the computational complexity and link overhead, feedback on the channel quality is proposed to be computed using a mean value of the vertical angle (instead of the exact instantaneous value), as well as the distance information. In addition, a two-bit feedback scheme is proposed for the group-based user scheduling, which relies on both the distance and the vertical angle, and differs from the conventional one-bit feedback of the distance only. The outage probability and sum-rate expressions are derived analytically, which show a very good match with the simulation data. Numerical results verify that the practical feedback scheme with the mean vertical angle achieves a near-optimal sum-rate performance, and the two-bit feedback significantly outperforms the one-bit feedback.
A Novel Osteogenic Cell Line That Differentiates Into GFP-Tagged Osteocytes and Forms Mineral With a Bone-Like Lacunocanalicular Structure

Osteocytes, the most abundant cells in bone, were once thought to be inactive, but are now known to have multifunctional roles in bone, including in mechanotransduction, regulation of osteoblast and osteoclast function and phosphate homeostasis. Because osteocytes are embedded in a mineralized matrix and are challenging to study, there is a need for new tools and cell models to understand their biology. We have generated two clonal osteogenic cell lines, OmGFP66 and OmGFP10, by immortalization of primary bone cells from mice expressing a membrane-targeted GFP driven by the Dmp1-promoter. One of these clones, OmGFP66, has unique properties compared with previous osteogenic and osteocyte cell models and forms 3-dimensional mineralized bone-like structures, containing highly dendritic GFP-positive osteocytes, embedded in clearly defined lacunae. Confocal and electron microscopy showed that structurally and morphologically, these bone-like structures resemble bone in vivo, even mimicking the lacunocanalicular ultrastructure and 3D spacing of in vivo osteocytes. In osteogenic conditions, OmGFP66 cells express alkaline phosphatase (ALP), produce a mineralized type I collagen matrix, and constitutively express the early osteocyte marker, E11/gp38. With differentiation they express osteocyte markers, Dmp1, Phex, Mepe, Fgf23, and the mature osteocyte marker, Sost. They also express RankL, Opg, and Hif1α, and show expected osteocyte responses to PTH, including downregulation of Sost, Dmp1, and Opg and upregulation of RankL and E11/gp38. Live cell imaging revealed the dynamic process by which OmGFP66 bone-like structures form, the motile properties of embedding osteocytes and the integration of osteocyte differentiation with mineralization. The OmGFP10 clone showed an osteocyte gene expression profile similar to OmGFP66, but formed less organized bone nodule-like mineral, similar to other osteogenic cell models. Not only do these cell lines provide useful new tools for mechanistic and dynamic studies of osteocyte differentiation, function, and biomineralization, but OmGFP66 cells have the unique property of modeling osteocytes in their natural bone microenvironment. © 2019 American Society for Bone and Mineral Research.
Delayed Lactogenesis II is Associated With Lower Sleep Efficiency and Greater Variation in Nightly Sleep Duration in the Third Trimester.

Background:Metabolic and hormonal disturbances are associated with sleep disturbances and delayed onset of lactogenesis II.Research aims:The aim of this study was to measure sleep using wrist actig...
The Sub-Neptune Desert and Its Dependence on Stellar Type: Controlled by Lifetime X-Ray Irradiation

Short-period sub-Neptunes with substantial volatile envelopes are among the most common type of known exoplanets. However, recent studies of the Kepler population have suggested a dearth of sub-Neptunes on highly irradiated orbits, where they are vulnerable to atmospheric photoevaporation. Physically, we expect this "photoevaporation desert" to depend on the total lifetime X-ray and extreme ultraviolet flux, the main drivers of atmospheric escape. In this work, we study the demographics of sub-Neptunes as a function of lifetime exposure to high-energy radiation and host-star mass. We find that for a given present-day insolation, planets orbiting a 0.3 solar mass star experience approximately 100 times more X-ray flux over their lifetimes versus a 1.2 solar mass star. Defining the photoevaporation desert as a region consistent with zero occurrence at 2 sigma, the onset of the desert happens for integrated X-ray fluxes greater than 1.43 times 10 (sup 22) to 8.23 times 10 (sup 20) as a function of planetary radii for 1.8 to 4 Earth radius. We also compare the location of the photoevaporation desert for different stellar types. We find much greater variability in the desert onset in the bolometric flux space compared to the integrated X-ray flux space, suggestive of photoevaporation driven by steady-state stellar X-ray emissions as the dominant control on desert location. Finally, we report tentative evidence for the sub-Neptune valley, first seen around Sun-like stars, for M&K dwarfs. The discovery of additional planets around low-mass stars from surveys such as the Transiting Exoplanet Survey Satellite (TESS) mission will enable detailed exploration of these trends.
Characterization of Cu-ZSM-5 Prepared by Solid-State Ion Exchange of H-ZSM-5 with CuCl

The solid-state ion exchange (SSIE) of H-ZSM-5 by CuCl vapor was investigated with the objective of establishing the effects of the temperature at which exchange is carried out on the level of prot...
Synthesis of α-Trimethylsilylallenones

Abstract Electrophilically initiated 1,2-TMS group migration-elimination within bis(O-TMS) and 1-(O-TMS), 4-(O-mesyl) derivatives of 1-TMS-2-alkyn-1,4-diols affords α-TMS allenones.
Transformation of N,N-dimethylaniline-N-oxides into N-methylindolines by a tandem Polonovski–Mannich reaction

We report here a sequence of reactions for the synthesis of diversely substituted N-methylindolines from the corresponding N,N-dimethylaniline-N-oxides through a Polonovski–Mannich cyclization. Indolines are obtained in 47–61% yield from the corresponding aniline-N-oxides in one laboratory operation.
A convenient synthetic method for amide oxidation

Abstract Diazotization of o-aminobenzamides in methanol in the presence of a catalytic amount of CuCl affords α-methoxybenzamides in good yields.
Vinylcyclobutanols: A Composite Functional Group?

The effect of small strained rings on chemical reactivity was probed by the examination of the behavior of vinylcyclobutanols as terminators in cyclization reactions. The substrates were readily available by the addition of vinyllithium reagents bearing acetals as cyclization initiators to cyclobutanone. Bronsted and Lewis acids both promoted cyclization in contrast to vinylcyclopropanol terminators for which Bronsted acids failed. The products are spirocycles consisting of a cyclopentanone derived from ring expansion of the cyclobutanol and the second ring derived by attack of the terminator on the initiator. Spirocyclization to [4.5] and [4.6] systems proceeded smoothly, whereas spirocyclization to a [4.7] system failed. Attaching the cyclization termini to a preexisting ring system (whereby tricycles consisting of a fused bicycle and a spirocycle are formed) expands the scope of the cyclization to include the [4.7] ring system even at 0.01 M, a rather high concentration for such an unfavorable ring sys...
Facile Synthesis of Benzotriazines and Indoles by Ring-Scissions of α-Benzotriazol-1-yl Hydrazones

Abstract: α-(Benzotriazol-1-yl)hydrazones 2a-d and 13a-c were prepared by refluxing the corresponding α-(benzotriazol-1-yl)ketones with p-tosyl hydrazide or benzenesulfonyl hydrazide. Treatment of 2a-b with n-butyllithium in the presence of TMEDA gave benzotriazines 6a-b, while lithiation of 13a-c resulted in indole derivatives 16a-c, depending on the structure of the hydrazones.
PANOPLY: Omics-Guided Drug Prioritization Method Tailored to an Individual Patient

PurposeThe majority of patients with cancer receive treatments that are minimally informed by omics data. We propose a precision medicine computational framework, PANOPLY (Precision Cancer Genomic Report: Single Sample Inventory), to identify and prioritize drug targets and cancer therapy regimens.Materials and MethodsThe PANOPLY approach integrates clinical data with germline and somatic features obtained from multiomics platforms and applies machine learning and network analysis approaches in the context of the individual patient and matched controls. The PANOPLY workflow uses the following four steps: selection of matched controls to the patient of interest; identification of patient-specific genomic events; identification of suitable drugs using the driver-gene network and random forest analyses; and provision of an integrated multiomics case report of the patient with prioritization of anticancer drugs.ResultsThe PANOPLY workflow can be executed on a stand-alone virtual machine and is also available ...
Effects of oral domoic acid exposure on maternal reproduction and infant birth characteristics in a preclinical nonhuman primate model.

Abstract Domoic Acid (DA) is a naturally-occurring excitotoxin, produced by marine algae, which can bioaccumulate in shellfish and finfish. The consumption of seafood contaminated with DA is associated with gastrointestinal illness that, in the case of high DA exposure, can evolve into a spectrum of responses ranging from agitation to hallucinations, memory loss, seizures and coma. Because algal blooms that produce DA are becoming more widespread and very little is known about the dangers of chronic, low-dose exposure, we initiated a preclinical study focused on the reproductive and developmental effects of DA in a nonhuman primate model. To this end, 32 adult female Macaca fascicularis monkeys were orally exposed to 0, 0.075 or 0.15 mg/kg/day DA on a daily basis, prior to and during pregnancy. Females were bred to non-exposed males and infants were evaluated at birth. Results from this study provided no evidence of changes in DA plasma concentrations with chronic exposure. DA exposure was not associated with reproductive toxicity or adverse changes in the physical characteristics of newborns. However, in an unanticipated finding, our clinical observations revealed the presence of subtle neurological effects in the form of intentional tremors in the exposed adult females. While females in both dose groups displayed increased tremoring, the effect was dose-dependent and observed at a higher rate in females exposed to 0.15 mg/kg/day. These results demonstrate that chronic, low-level exposure to DA is associated with injury to the adult CNS and suggest that current regulatory guidelines designed to protect human health may not be adequate for high-frequency shellfish consumers.
A Versatile Synthesis of 3-Substituted Indoles

Abstract A variety of 3-substituted indoles are prepared from 1-methyl-3-(benzotriazol-1-ylalkyl)indoles (1), which are readily available either from the condensation of 3-methylindole with N-(benzotriazol-1-ylalkyl)carbamates or from the alkylation and silylation of lithiated 1-methyl-3-(benzotriazol-1-ylmethyl)indole (2).
Synthesis of dibromophakellstatin and dibromoisophakellin

Abstract A short synthesis of the marine sponge alkaloids dibromophakellstatin ( 1 ) and dibromoisophakellin ( 2 ) is described. The synthesis of 1 centers on a putative biomimetic oxidative cyclization of imidazolone 5 . Thermal rearrangement of dibromophakellin ( 9 ) in the presence of K2CO3 afforded dibromoisophakellin ( 2 ).
Chiral Lewis acids derived from 1,8-naphthalenediylbis-(dichloroborane): Mechanistic aspects

Abstract Chiral Lewis acids derived from 1,8-Naphthalenediylbis(dichloroborane), a novel bidentate Lewis acid, have been found to be active catalysts for the asymmetric Diels-Alder reaction. Utilizing chiral ligands derived from amino acids, a range of enantioselectivities have been achieved with cyclopentadiene and various α,β-unsaturated aldehydes. Some mechanistic aspects of this novel asymmetric bidentate catalyst have been addressed.
Synthesis, Characterization, and Adsorbate Interactions of CoAPO-41 and CoAPSO-41 Molecular Sieves

Two novel medium pore cobalt-substituted aluminophosphate molecular sieves CoAPO-41 and CoAPSO-41 have been synthesized hydrothermally using di-n-propylamine as the organic template. These materials have been characterized by various physical methods including XRD, TGA, SEM, electron microprobe analysis, 27Al, 29Si, and 31P MAS NMR, UV−visible, and ESR spectroscopies. Substitution of cobalt into the framework has been established. Cobalt in CoAPO/CoAPSO-41 after calcination in O2 and subsequent dehydration and H2 treatment at high temperature activates molecular oxygen by forming a peroxocobalt adduct Co−O−O•. The peroxo species is unstable at temperatures above 573 K. Adsorption of molecules such as D2O, ND3, CH3OD, and CO on CoAPO/CoAPSO-41 materials after calcination, dehydration, and high-temperature hydrogen treatment forms complexes with Co(II) from the framework as revealed by ESR measurements at 4.5 and 77 K.
A New Catalyst for a Pd Catalyzed Alder Ene Reaction. A Total Synthesis of (+)-Cassiol

The scope of the palladium catalyzed cycloisomerization of enynes in an Alder ene type fashion that led to a new catalytic system was explored in the context of a synthetic strategy to the antiulcerogenic agent (+)-cassiol. In a model study, the effect of six-membered ring formation, the presence of a carbonyl group in the tether, and the steric hindrance of the alkene conspire to prevent the cycloisomerization under the “standard” conditions. Two variables proved key in the development of a new catalytic system that has proven to be effective, the absence of traditional ligands and the choice of acid. An effective synthesis of (+)-cassiol was accomplished in which this new reaction played a key. A lipase served to introduce the chirality, and a palladium(0) catalyzed reaction was important in elaborating a side chain. The final adjustment of oxidation level made advantageous use of a platinum catalyzed enone hydrosilyation.
PHOSPHATE TUNGSTEN BRONZES — A NEW FAMILY OF QUASI-LOW-DIMENSIONAL METALLIC OXIDES

A brief introduction is presented on transition metal oxide bronzes and their relationship to the phosphate tungsten bronzes; the latter compounds are the major focus of this review. The phosphate tungsten bronzes (PTB) are a new class of quasi-low-dimensional materials which exhibit charge density wave (CDW) instabilities. The growth of single crystals and investigation of the physical properties including the temperature dependence of the electrical resistivity and magnetic susceptibility on oriented single crystals are discussed for selected members of the major families in the PTB’s. Correlation of the physical measurement data with structural properties, X-ray diffraction data and results of the theoretical band structure calculations are also presented.
Stereospecific preparation of (Z)- and (E)-2,3-difluoro-3-stannylacrylic ester synthons and a new, efficient stereospecific route to (Z)- and (E)-2,3-difluoroacrylic esters.

The (Z)-2,3-difluoro-3-stannylacrylic ester is readily prepared from (Z)-1,2-difluorovinyltriethylsilane via stereospecific stannyl/silyl exchange with KF/(Bu3Sn)2O or Bu3SnCl in DMF at 70 °C. The corresponding (E)-2,3-difluoro-3-stannylacrylate is prepared by stereospecific carbonylation of (E)-1,2-difluorovinyl iodide followed by low temperature/in situ stannylation of the resultant (Z)-2,3-difluoroacrylic ester. With Cu(I) iodide and Pd(PPh3)4 catalysis, the (Z)- and (E)-stannylacrylate esters readily couple with aryl iodides and vinyl bromides, as well as 2-iodothiophene, at room temperature to stereospecifically produce the respective (E)- and (Z)-2,3-difluoro-3-aryl substituted acrylic esters or conjugated dienes in high yields.
Nonracemic Diarylmethanols From CuH-Catalyzed Hydrosilylation of Diaryl Ketones

An efficient method for the synthesis of nonracemic diarylmethanols has been developed. The use of (R)-(−)-(DTBM-SEGPHOS)CuH effects highly enantioselective 1,2-hydrosilylation of prochiral diaryl ketones.
Two novel forms of ERG oscillation in Drosophila: age and activity dependence.

Over an animal’s lifespan, neuronal circuits and systems often decline in an inherently heterogeneous fashion. To compare the age-dependent progression of changes in visual behavior with alteration...
Synthesis of the ring system of phomactin D using a Suzuki macrocyclization.

The ring system of phomactin D was synthesized in racemic form in an efficient manner from 2,3-dimethylcyclohexanone. Notable transformations include (1) an alkylation of the enolate of a vinylogous thiolester to install a quaternary stereocenter, (2) a conjugate addition of cyanide to an α,β-unsaturated aldehyde, (3) the formation of a Weinreb amide directly from a cyanohydrin, and (4) an intramolecular Pd-mediated Suzuki coupling of a B-alkyl-9-BBN derivative and a vinyl iodide to form the macrocyclic ring.
Copper(II) nitrate on clay (claycop)-hydrogen peroxide: Selective and solvent-free oxidations using microwaves

Abstract Claycop [copper(II) nitrate on clay]-hydrogen peroxide is an efficient and selective oxidizing reagent for a variety of compounds under solvent-free conditions using microwaves.
Metallacrown Ethers: Unique Organometallic Ligands

Abstract Metallacrown ethers are a unique class of complexes that form when R2PX-(CH2CH2O)nCH2CH2XPR2 (X = –, O; R = Ph, alkoxy; n = 3–5) ligands chelate to transition metals. Metallacrown ethers with cis-coordinated phosphines (cis-metallacrown ethers) contain a crown ether-like pocket and exhibit size-selective binding of alkali metal cations similar to that observed with the crown ethers. Binding of Li+ and Hg2+ to cis-Mo(CO)4{R2PX(CH2CH2O)nCH2CH2XPPh2P,P′} metallacrown ethers can, under certain circumstances, activate the carbonyl ligands cis to the phosphines to nucleophilic attack or dissociation. The cis-metallacrown ethers are also capable of binding water via coordination to the metal center and hydrogen bonding to the ethers. Recently, octahedral metallacrown ethers with trans-coordinated phosphines (trans-metallacrown ethers) have been prepared. The conformations of these complexes are quite different from those of the cis-metallacrown ethers with more extended metallacrown ether chains and the...
Synthesis of racemic and enantiomerically pure 2′‐thia‐2′,3′‐dideoxycytidine as potential anti‐hepatitis B virus agents

A novel class of nucleosides with the C1, atom bonded to three hetero atoms was synthesized. 2′-Thia-2′,3′-dideoxycytidine was the pilot compound of this series. (±)-β-2′-Thia-1′,3′-dideoxycytidine (6) and (±)-α-2′-thia-2′,3′-dideoxycytidine (7) were synthesized from (±)-3-mercapto-1,2-propanediol. The synthesis of the enantiomerically pure 2′-thia-2′,3′-dideoxycytidines (α-D-form, β-D-form, α-1-form and β-L-form) from optically pure (S)-(2,2-dimethyl-1,3-dioxalan-yl)methyl p-toluenesulfonate (8) and its (R)-isomer 18 was also described. The preliminary biological results showed that (+)-β-D-2′-thia-2′,3′-dideoxycytidine (26) was the most active against human hepatitis B virus with an ED50 of 3 μM.
Tests as maintainable assets via auto-generated spies: a case study involving the scala collections library's iterator trait

In testing stateful abstractions, it is often necessary to record interactions, such as method invocations, and express assertions over these interactions. Following the Test Spy design pattern, we can reify such interactions programmatically through additional mutable state. Alternatively, a mocking framework, such as Mockito, can automatically generate test spies that allow us to record the interactions and express our expectations in a declarative domain-specific language. According to our study of the test code for Scala's Iterator trait, the latter approach can lead to a significant reduction of test code complexity in terms of metrics such as code size (in some cases over 70% smaller), cyclomatic complexity, and amount of additional mutable state required. In this tools paper, we argue that the resulting test code is not only more maintainable, readable, and intentional, but also a better stylistic match for the Scala community than manually implemented, explicitly stateful test spies.
Why Are CD8 T Cell Epitopes of Human Influenza A Virus Conserved

The high degree of conservation of CD8 T cell epitopes of influenza A virus (IAV) may allow for the development of T cell-inducing vaccines that provide protection across different strains and subtypes. This conservation is not fully explained by functional constraint, since an additional mutation(s) can compensate for the replicative fitness loss of IAV escape variants. Here, we propose three additional mechanisms that contribute to the conservation of CD8 T cell epitopes of IAV. First, influenza-specific CD8 T cells may protect predominantly against severe pathology rather than infection and may have only a modest effect on transmission. Second, polymorphism of the human major histocompatibility complex class I (MHC-I) gene restricts the advantage of an escape variant to only a small fraction of the human population who carry the relevant MHC-I alleles. Finally, infection with CD8 T cell escape variants may result in a compensatory increase in the responses to other epitopes of IAV. We use a combination of population genetics and epidemiological models to examine how the interplay between these mechanisms affects the rate of invasion of IAV escape variants. We conclude that for a wide range of biologically reasonable parameters, the invasion of an escape variant virus will be slow, with a timescale of a decade or more. The results suggest T cell-inducing vaccines do not engender the rapid evolution of IAV. Finally, we identify key parameters whose measurement will allow for more accurate quantification of the long-term effectiveness and impact of universal T cell-inducing influenza vaccines.IMPORTANCE Universal influenza vaccines against the conserved epitopes of influenza A virus have been proposed to minimize the burden of seasonal outbreaks and prepare for the pandemics. However, it is not clear how rapidly T cell-inducing vaccines will select for viruses that escape these T cell responses. Our mathematical models explore the factors that contribute to the conservation of CD8 T cell epitopes and how rapidly the virus will evolve in response to T cell-inducing vaccines. We identify the key biological parameters to be measured and questions that need to be addressed in future studies.
Metal carbonyl analogues of iron–sulfur clusters found in metalloenzyme chemistry

Abstract Many iron–sulfur metalloenzymes are based on Fe 4 S 4 cubes in which the iron sites have high-spin tetrahedral coordination. Such Fe 4 S 4 cubes can be obtained by dimerization of Fe 2 S 2 rhombuses. Similar cluster aggregation processes can be observed for model FeS systems in which the high-spin tetrahedral iron sites are replaced by low-spin octahedral Fe(CO) 3 S 3 sites. The Fe 2 S 2 analogue for the metal carbonyl system is Fe 2 (CO) 6 S 2 , whose ground-state structure contains a Fe 2 S 2 tetrahedron with FeFe and SS bonds as well as four FeS bonds. However, much of the observed photochemistry of Fe 2 (CO) 6 S 2 can be rationalized by a coordinatively unsaturated rhombus photointermediate in which the FeFe and SS bonds of the ground state have broken in a concerted process in accordance with molecular orbital calculations. Additional insight into the chemistry of these iron carbonyl sulfides is obtained by replacement of the sulfur atoms by isoelectronic RP groups. Thus the stable Fe 2 (CO) 6 (P t Bu) 2 tetrahedron and the stable rhombus Fe 2 (CO) 6 (POC 6 H 2 -4-Me-2,6- t Bu 2 ) 2 can both be isolated and characterized. In addition, the reaction of Na 2 Fe(CO) 4 with i Pr 2 NPCl 2 gives the phosphorus-bridging carbonyl derivative ( i Pr 2 NP) 2 COFe 2 (CO) 6 , which undergoes thermal reactions with unsaturated organic molecules to give adducts of their CC, CO, or CN bonds to the phosphorus atoms of a Fe 2 (CO) 6 (PN i Pr 2 ) 2 unit generated by extrusion of the phosphorus-bridging carbonyl group. A low-temperature IR spectroscopic study of ( i Pr 2 NP) 2 COFe 2 (CO) 6 photolyzed in a Nujol matrix provides evidence for an unstable nearly square Fe 2 (CO) 6 (PN i Pr 2 ) 2 rhombus.
Intramolecular anodic olefin coupling reactions: the use of an allylic alkoxy group for controlling relative stereochemistry

The study of intramolecular anodic olefin coupling reactions arising from diene substrates having an allylic alkoxy group have been studied. In all cases, the coupling reactions proceeded smoothly without elimination of the allylic alkoxy group. In addition, the reactions were found to afford five-membered ring products in a diastereoselective fashion. Substrates having both cis- and trans-disubstituted allyl silane olefin participants led to different ratios of products indicating that the cyclization reactions were under kinetic control.
Is diazomethane addition to chiral α-keto esters subject to substrate diastereocontrol?

The uncatalyzed reaction of diazomethane with chiral benzoylformate esters results in the formation of α-oxiranyl esters without significant facial discrimination in almost every case.
Synthesis of aryl 2‐(2‐imidazolyl)ethyl ketones

The Claisen-Schmidt condensation of 1-(triphenylmethyl)-2-imidazolecarboxaldehyde with acetophenones yielded 1-aryl-3-[1-(triphenylmethyl)-2-imidazolyl]propen-1-ones 7. Selective catalytic hydrogenation over platinum of 7 furnished 1-aryl-3-(2-imidazolyl)-1-propanones 8. An alternate synthesis of 8 started with sodium borohydride reduction of 7 to give allylic alcohols, 1-aryl-3-[1-(triphenylmethyl)-2-imidazolyl]-2-propen-1-ols 10, which were rearranged by hot aqueous sodium to 8. Acid hydrolysis of 8 provided the title compounds and triphenylmethanol.
Green chemistry approach to the synthesis of N-substituted piperidones.

An efficient green chemistry approach to the synthesis of N-substituted piperidones and piperidines was developed and applied to the synthesis of 1-(2-pyridinylmethyl)-piperidin-4-one, 1, a key starting material for the synthesis of LY317615, an antiangiogenic agent currently under development at Eli Lilly and Company (Chart 1).1 The general utility of this methodology, which presents significant advantages over the classical Dieckman approach to this class of compounds, was also demonstrated by the direct synthesis of a series of substituted piperidones and piperidines, including potential dopamine D4 receptor antagonists 2 and 3, that have been evaluated in the clinic as antipsychotic agents (Chart 2).2
Mercury and Reactive Halogens: The Thermochemistry of Hg + {Cl2, Br2, BrCl, ClO, and BrO}

Accurate reaction enthalpies have been calculated using the CCSD(T) method and sequences of correlation consistent basis sets for the reactions of Hg with a series of small halogen-containing molec...
BRIDGED POLYSILSESQUIOXANES. HIGHLY POROUS HYBRID ORGANIC-INORGANIC MATERIALS

This contribution reviews a new family of inorganic-organic hybrid materials that are assembled by sol-gel polymerization of polyfunctional molecular building blocks. These bridged polysilsesquioxanes are three-dimensional network materials that are distinguished by incorporation of an organic fragment as an integral component of the network. The intimate association of the organic and inorganic phase, a true molecular composite, coupled with the variability of the organic component, permits engineering of both chemical and physical properties of the material. The paper reviews bridged polysilsesquioxanes, arylene-bridged polysilsesquioxanes, alkylene-bridged polysilsesquioxanes; and their applications.
Stereoselective synthesis of dihydroisocoumarin moiety of microbial agent AI-77-B: a Diels-Alder based strategy

The dihydroisocoumarin fragment of the gastroprotective natural product AI-77-B has been synthesized in optically active form by using a regiospecific Diels-Alder reaction of 1-methoxy-1,3-cyclohexadiene and an acetylenic ester derivative, prepared stereoselectively from leucinal.
Income inequality and education revisited: persistence, endogeneity and heterogeneity

This article presents new results on the relationship between income inequality and education expansion – that is, increasing average years of schooling and reducing inequality of schooling. When d...
Evaluation of sub-monthly oceanographic signal in GRACE "daily" swath series using altimetry

Abstract. Bottom pressure estimates from three different Gravity Recovery and Climate Experiment (GRACE) series (an experimental Center for Space Research (CSR) swath series, ITSG2016, and ITSG2018) and two global ocean models (OMCT and MPIOM) are compared to Jason altimetry sea level anomaly estimates in order to determine the accuracy of the GRACE and model data at sub-monthly timescales. We find that the GRACE series are capable of explaining 25 %–75 % of the sub-monthly altimetric variability over most of those ocean regions that have high signal strength. All three GRACE series explain more of the sub-monthly variability than the de-aliasing products they were created with. Upon examination over finer frequency bands, the GRACE series prove superior at explaining the altimetric signal for signals with periods as short as 10 d.
Commanding Nature by Obeying Her: A Review Essay on Joel Mokyr’s A Culture of Growth

Why is modern society capable of cumulative innovation? In A Culture of Growth: The Origins of the Modern Economy, Joel Mokyr persuasively argues that sustained technological progress stemmed from a change in cultural beliefs. The change occurred gradually during the seventeenth and eighteenth century and was fostered by an intellectual elite that formed a transnational community and adopted new attitudes toward the creation and diffusion of knowledge, setting the foundation for the ethos of modern science. The book is a significant contribution to the growing literature that links culture and economics. This review discusses Mokyr’s historical analysis in relation to the following questions: What is culture and how should we use it in economics? How can culture explain modern economic growth? Will the culture of growth that caused modern prosperity persist in the future?
Early Stopping for Kernel Boosting Algorithms: A General Analysis With Localized Complexities

Early stopping of iterative algorithms is a widely used form of regularization in statistics, commonly used in conjunction with boosting and related gradient-type algorithms. Although consistency results have been established in some settings, such estimators are less well-understood than their analogues based on penalized regularization. In this paper, for a relatively broad class of loss functions and boosting algorithms (including $L^{2}$ -boost, LogitBoost, and AdaBoost, among others), we exhibit a direct connection between the performance of a stopped iterate and the localized Gaussian complexity of the associated function class. This connection allows us to show that the local fixed point analysis of Gaussian or Rademacher complexities, now standard in the analysis of penalized estimators, can be used to derive optimal stopping rules. We derive such stopping rules in detail for various kernel classes and illustrate the correspondence of our theory with practice for Sobolev kernel classes.
Protein structure prediction using sparse NOE and RDC restraints with Rosetta in CASP13

Computational methods that produce accurate protein structure models from limited experimental data, for example, from nuclear magnetic resonance (NMR) spectroscopy, hold great potential for biomedical research. The NMR-assisted modeling challenge in CASP13 provided a blind test to explore the capabilities and limitations of current modeling techniques in leveraging NMR data which had high sparsity, ambiguity, and error rate for protein structure prediction. We describe our approach to predict the structure of these proteins leveraging the Rosetta software suite. Protein structure models were predicted de novo using a two-stage protocol. First, low-resolution models were generated with the Rosetta de novo method guided by nonambiguous nuclear Overhauser effect (NOE) contacts and residual dipolar coupling (RDC) restraints. Second, iterative model hybridization and fragment insertion with the Rosetta comparative modeling method was used to refine and regularize models guided by all ambiguous and nonambiguous NOE contacts and RDCs. Nine out of 16 of the Rosetta de novo models had the correct fold (global distance test total score > 45) and in three cases high-resolution models were achieved (root-mean-square deviation < 3.5 a). We also show that a meta-approach applying iterative Rosetta + NMR refinement on server-predicted models which employed non-NMR-contacts and structural templates leads to substantial improvement in model quality. Integrating these data-assisted refinement strategies with innovative non-data-assisted approaches which became possible in CASP13 such as high precision contact prediction will in the near future enable structure determination for large proteins that are outside of the realm of conventional NMR.
Distortion of surfaces in graph manifolds

Let S ↬ N be an immersed horizontal surface in a 3 –dimensional graph manifold. We show that the fundamental group of the surface S is quadratically distorted whenever the surface is virtually embedded (ie separable) and is exponentially distorted when the surface is not virtually embedded.
Simulated Annealing for JPEG Quantization

JPEG is one of the most widely used image formats, but in some ways remains surprisingly unoptimized, perhaps because some natural optimizations would go outside the standard that defines JPEG. We show how to improve JPEG compression in a standard-compliant, backward-compatible manner, by finding improved default quantization tables. We describe a simulated annealing technique that has allowed us to find several quantization tables that perform better than the industry standard, in terms of both compressed size and image fidelity. Specifically, we derive tables that reduce the FSIM error by over 10% while improving compression by over 20% at quality level 95 in our tests; we also provide similar results for other quality levels. While we acknowledge our approach can in some images lead to visible artifacts under large magnification, we believe use of these quantization tables, or additional tables that could be found using our methodology, would significantly reduce JPEG file sizes with improved overall image quality.
Partial duality and closed 2-cell embeddings

In 2009 Chmutov introduced the idea of partial duality for embeddings of graphs in surfaces. We discuss some alternative descriptions of partial duality, which demonstrate the symmetry between vertices and faces. One is in terms of band decompositions, and the other is in terms of the gem (graph-encoded map) representation of an embedding. We then use these to investigate when a partial dual is a closed 2-cell embedding, in which every face is bounded by a cycle in the graph. We obtain a necessary and sufficient condition for a partial dual to be closed 2-cell, and also a sufficient condition for no partial dual to be closed 2-cell.
Revealing the Unseen: How to Expose Cloud Usage While Protecting User Privacy

Cloud users have little visibility into the performance characteristics and utilization of the physical machines underpinning the virtualized cloud resources they use. This uncertainty forces users and researchers to reverse engineer the inner workings of cloud systems in order to understand and optimize the conditions their applications operate. At Massachusetts Open Cloud (MOC), as a public cloud operator, we'd like to expose the utilization of our physical infrastructure to stop this wasteful effort. Mindful that such exposure can be used maliciously for gaining insight into other user's workloads, in this position paper we argue for the need for an approach that balances openness of the cloud overall with privacy for each tenant inside of it. We believe that this approach can be instantiated via a novel combination of several security and privacy technologies. We discuss the potential benefits, implications of transparency for cloud systems and users, and technical challenges/possibilities.
Crowdsourcing swarm manipulation experiments: A massive online user study with large swarms of simple robots

Microand nanorobotics have the potential to revolutionize many applications including targeted material delivery, assembly, and surgery. The same properties that promise breakthrough solutions—small size and large populations— present unique challenges to generating controlled motion. We want to use large swarms of robots to perform manipulation tasks; unfortunately, human-swarm interaction studies as conducted today are limited in sample size, are difficult to reproduce, and are prone to hardware failures. We present an alternative. This paper examines the perils, pitfalls, and possibilities we discovered by launching SwarmControl.net, an online game where players steer swarms of up to 500 robots to complete manipulation challenges. We record statistics from thousands of players, and use the game to explore aspects of largepopulation robot control. We present the game framework as a new, open-source tool for large-scale user experiments. Our results have potential applications in human control of microand nanorobots, supply insight for automatic controllers, and provide a template for large online robotic research experiments.