cssi/SciSciGPT-SciSciNet huggingface dataset:
Monodromy of monomially admissible Fukaya-Seidel categories mirror to toric varieties

Abstract Mirror symmetry for a toric variety involves Laurent polynomials whose symplectic topology is related to the algebraic geometry of the toric variety. We show that there is a monodromy action on the monomially admissible Fukaya-Seidel categories of these Laurent polynomials as the arguments of their coefficients vary that corresponds under homological mirror symmetry to tensoring by a line bundle naturally associated to the monomials whose coefficients are rotated. In the process, we introduce the monomially admissible Fukaya-Seidel category as a new interpretation of the Fukaya-Seidel category of a Laurent polynomial on ( C ⁎ ) n , which has other potential applications, and give evidence of homological mirror symmetry for non-compact toric varieties.
A note on Masuoka’s theorem for semisimple irreducible Hopf algebras

Masuoka proved (Proc Am Math Soc 137(6):1925–1932, 2009) that a finite-dimensional irreducible Hopf algebra H in positive characteristic is semisimple if and only if it is commutative semisimple if and only if the Hopf subalgebra generated by all primitives is semisimple. In this note, we give another proof of this result by using Hochschild cohomology of coalgebras.
Near Optimal Algorithms for Hard Submodular Programs with Discounted Cooperative Costs

In this paper, we investigate a class of submodular problems which in general are very hard. These include minimizing a submodular cost function under combinatorial constraints, which include cuts, matchings, paths, etc., optimizing a submodular function under submodular cover and submodular knapsack constraints, and minimizing a ratio of submodular functions. All these problems appear in several real world problems but have hardness factors of $\Omega(\sqrt{n})$ for general submodular cost functions. We show how we can achieve constant approximation factors when we restrict the cost functions to low rank sums of concave over modular functions. A wide variety of machine learning applications are very naturally modeled via this subclass of submodular functions. Our work therefore provides a tighter connection between theory and practice by enabling theoretically satisfying guarantees for a rich class of expressible, natural, and useful submodular cost models. We empirically demonstrate the utility of our models on real world problems of cooperative image matching and sensor placement with cooperative costs.
Regulating Markets for Gestational Care: Comparative Perspectives on Surrogacy in the United States and India.

There are many jurisdictions in the world where there is no legislation or case law that addresses surrogacy. In those jurisdictions, people freely enter into contracts for the sale and purchase of gestational care (defined below). Eighteen U.S. states and India, as well as at least forty countries, have no legislation or case law that permits, prohibits, or regulates surrogacy. This regulatory lacuna typically occurs either because of a failure to reach a consensus on legislation about the issue or sheer neglect of it.
Dishonest Behavior: Sin Big or Go Home

Abstract Economic agents face many different types of economic incentives when making financial and moral decisions. We provide experimental data from a population that uniquely responds to incentives to lie compared to previously studied populations. We conduct a standard 6-sided die rolling lying study within a population that believes that God has knowledge of all their actions. Within this population, we find that those who attend church frequently appear to refrain from lying while those who attend less frequently do lie, but without any attempt to disguise their lies as seen in more secular populations. Our results complement recent theoretical work on lying.
Energy demand substitution from biomass to imported kerosene: Evidence from Tanzania

Abstract We analyze domestic household energy demand and use patterns in Tanzania, using a detailed household survey of purchase transactions, a multivariate probit model, and the QUAIDS modeling framework. The main fuel sources that we study are kerosene, charcoal, and firewood. These three accounted for 96.5% of spending on energy by households. Charcoal and firewood are used for cooking while kerosene is used for lighting and cooking. Kerosene is almost exclusively imported, while charcoal and firewood are produced domestically. These fuel sources are important, given the impacts of wood harvesting on the environment and kerosene imports on public finances. We find a statistically significant response in kerosene demand to charcoal prices, suggesting a pattern of substitution, but no strong substitution relationships between other fuel pairs. These results, which we use in a simulation of tariff change, imply that policies centered on price changes may not be effective in changing consumer behavior unless alternative sources of energy are readily accessible.
tRNA Fragments Show Intertwining with mRNAs of Specific Repeat Content and Have Links to Disparities

tRNA-derived fragments (tRF) are a class of potent regulatory RNAs. We mined the datasets from The Cancer Genome Atlas (TCGA) representing 32 cancer types with a deterministic and exhaustive pipeline for tRNA fragments. We found that mitochondrial tRNAs contribute disproportionally more tRFs than nuclear tRNAs. Through integrative analyses, we uncovered a multitude of statistically significant and context-dependent associations between the identified tRFs and mRNAs. In many of the 32 cancer types, these associations involve mRNAs from developmental processes, receptor tyrosine kinase signaling, the proteasome, and metabolic pathways that include glycolysis, oxidative phosphorylation, and ATP synthesis. Even though the pathways are common to multiple cancers, the association of specific mRNAs with tRFs depends on and differs from cancer to cancer. The associations between tRFs and mRNAs extend to genomic properties as well; specifically, tRFs are positively correlated with shorter genes that have a higher density in repeats, such as ALUs, MIRs, and ERVLs. Conversely, tRFs are negatively correlated with longer genes that have a lower repeat density, suggesting a possible dichotomy between cell proliferation and differentiation. Analyses of bladder, lung, and kidney cancer data indicate that the tRF-mRNA wiring can also depend on a patient9s sex. Sex-dependent associations involve cyclin-dependent kinases in bladder cancer, the MAPK signaling pathway in lung cancer, and purine metabolism in kidney cancer. Taken together, these findings suggest diverse and wide-ranging roles for tRFs and highlight the extensive interconnections of tRFs with key cellular processes and human genomic architecture. Significance: Across 32 TCGA cancer contexts, nuclear and mitochondrial tRNA fragments exhibit associations with mRNAs that belong to concrete pathways, encode proteins with particular destinations, have a biased repeat content, and are sex dependent.
Weak electric-field detection with sub-1 Hz resolution at radio frequencies using a Rydberg atom-based mixer

Rydberg atoms have been used for measuring radio-frequency (RF) electric (E)-fields due to their strong dipole moments over the frequency range of 500 MHz-1 THz. For this, electromagnetically induced transparency (EIT) within the Autler-Townes (AT) regime is used such that the detected E-field is proportional to AT splitting. However, for weak E-fields AT peak separation becomes unresolvable thus limiting the minimum detectable E-field. Here, we demonstrate using the Rydberg atoms as an RF mixer for weak E-field detection well below the AT regime with frequency discrimination better than 1 Hz resolution. A heterodyne detection scenario with two E-fields incident on a vapor cell filled with cesium atoms is used. One E-field at 19.626000 GHz drives the 34D5/2 → 35P3/2 Rydberg transition and acts as a local oscillator (LO) and a second signal E-field (Sig) of interest is at 19.626090 GHz. In the presence of the LO, the Rydberg atoms naturally down convert the Sig field to a 90 kHz intermediate frequency (IF) signal. This IF signal manifests as an oscillation in the probe laser intensity through the Rydberg vapor and is easily detected with a photodiode and lock-in amplifier. In the configuration used here, E-field strength down to ≈ 46 μV/m ± 2 μV/m were detected with a sensitivity of ≈ 79 μVm−1Hz−1/2. Furthermore, neighboring fields 0.1 Hz away and equal in strength to Sig could be discriminated without any leakage into the lock-in signal. For signals 1 Hz away and as high as +60 dB above Sig, leakage into the lock-in signal could be kept below -3 dB.
Look who’s talking now: Implications of AV’s explanations on driver’s trust, AV preference, anxiety and mental workload

Abstract Explanations given by automation are often used to promote automation adoption. However, it remains unclear whether explanations promote acceptance of automated vehicles (AVs). In this study, we conducted a within-subject experiment in a driving simulator with 32 participants, using four different conditions. The four conditions included: (1) no explanation, (2) explanation given before or (3) after the AV acted and (4) the option for the driver to approve or disapprove the AV’s action after hearing the explanation. We examined four AV outcomes: trust, preference for AV, anxiety and mental workload. Results suggest that explanations provided before an AV acted were associated with higher trust in and preference for the AV, but there was no difference in anxiety and workload. These results have important implications for the adoption of AVs.
The Evolving Role of CD8 + CD28 - Immunosenescent T Cells in Cancer Immunology.

Functional, tumor-specific CD8+ cytotoxic T lymphocytes drive the adaptive immune response to cancer. Thus, induction of their activity is the ultimate aim of all immunotherapies. Success of anti-tumor immunotherapy is precluded by marked immunosuppression in the tumor microenvironment (TME) leading to CD8+ effector T cell dysfunction. Among the many facets of CD8+ T cell dysfunction that have been recognized—tolerance, anergy, exhaustion, and senescence—CD8+ T cell senescence is incompletely understood. Naive CD8+ T cells require three essential signals for activation, differentiation, and survival through T-cell receptor, costimulatory receptors, and cytokine receptors. Downregulation of costimulatory molecule CD28 is a hallmark of senescent T cells and increased CD8+CD28− senescent populations with heterogeneous roles have been observed in multiple solid and hematogenous tumors. T cell senescence can be induced by several factors including aging, telomere damage, tumor-associated stress, and regulatory T (Treg) cells. Tumor-induced T cell senescence is yet another mechanism that enables tumor cell resistance to immunotherapy. In this paper, we provide a comprehensive overview of CD8+CD28− senescent T cell population, their origin, their function in immunology and pathologic conditions, including TME and their implication for immunotherapy. Further characterization and investigation into this subset of CD8+ T cells could improve the efficacy of future anti-tumor immunotherapy.
Phosphoramidites are efficient, green organocatalysts for the Michael reaction. Mechanistic insights into the phosphorus-catalyzed Michael reaction of alkynones and implications for asymmetric catalysis.

Hexamethylphosphorous triamide (HMPT) and other phosphoramidites and phosphites have been found to be efficient catalysts for the Michael reaction of alkenones and alkynones with malonates, α-cyano esters, β-keto esters, and nitro compounds. The relatively nontoxic, easily hydrolyzed HMPT catalyzes the Michael reaction within seconds at room temperature in the absence of a solvent, and the reaction is worked up simply by removing the catalyst in vacuo. The Michael reactions of alkynones, unlike those of alkenones, are shown to be irreversible. The implications for asymmetric catalysis are discussed.
Heavy-Metal Aromatic and Conjugated Species: Rings, Oligomers, and Chains of Tin in Li9-xEuSn6+x, Li9-xCaSn6+x, Li5Ca7Sn11, Li6Eu5Sn9, LiMgEu2Sn3, and LiMgSr2Sn3

The title compounds were synthesized from the elements by heating the corresponding mixtures at high temperature. Their structures were determined from single-crystal X-ray diffraction. Li9-xEuSn6+x, Li9-xCaSn6+x, Li5Ca7Sn11, and Li6Eu5Sn9 contain columns of stacked aromatic pentagons of Sn56- that are analogous to the cyclopentadienyl anion C5H5-. The pentagons are separated with Ca2+ or Eu2+ in the columns and resemble a polymeric metallocene. In addition to the columns, the isostructural Li9-xEuSn6+x and Li9-xCaSn6+x contain isolated tin atoms and bent tin trimers while Li5Ca7Sn11 and Li6Eu5Sn9 contain flat zigzag hexamers and flat zigzag infinite chains of tin, respectively. The isostructural LiMgEu2Sn3 and LiMgSr2Sn3 do not contain columns of pentagons but only flat zigzag infinite chains of tin. The aromaticity of the pentagons and the conjugation of the π-systems of the hexamers and the infinite chains are discussed. The title compounds are also characterized by magnetic and conductivity measurements.
Relative evolutionary rate inference in HyPhy with LEISR

We introduce LEISR (Likehood Estimation of Individual Site Rates, pronounced "laser"), a tool to infer relative evolutionary rates from protein and nucleotide data, implemented in HyPhy. LEISR is based on the popular Rate4Site (Pupko et al., 2002) approach for inferring relative site-wise evolutionary rates, primarily from protein data. We extend the original method for more general use in several key ways: (i) we increase the support for nucleotide data with additional models, (ii) we allow for datasets of arbitrary size, (iii) we support analysis of site-partitioned datasets to correct for the presence of recombination breakpoints, (iv) we produce rate estimates at all sites rather than at just a subset of sites, and (v) we implemented LEISR as MPI-enabled to support rapid, high-throughput analysis. LEISR is available in HyPhy starting with version 2.3.8, and it is accessible as an option in the HyPhy analysis menu ("Relative evolutionary rate inference"), which calls the HyPhy batchfile LEISR.bf.
Privacy-Preserving Auditing for Attribute-Based Credentials.

Privacy-enhancing attribute-based credentials (PABCs) allow users to authenticate to verifiers in a data-minimizing way, in the sense that users are unlinkable between authentications and only disclose those attributes from their credentials that are relevant to the verifier. We propose a practical scheme to apply the same data minimization principle when the verifiers’ authentication logs are subjected to external audits. Namely, we propose an extended PABC scheme where the verifier can further remove attributes from presentation tokens before handing them to an auditor, while preserving the verifiability of the audited tokens. We present a generic construction based on a signature, a signature of knowledge and a trapdoor commitment scheme, prove it secure in the universal composability framework, and give efficient instantiations based on the strong RSA and Decision Composite Residuosity (DCR) assumptions in the random-oracle model.
APC/CFZR-1 Controls SAS-5 Levels to Regulate Centrosome Duplication in Caenorhabditis elegans

As the primary microtubule-organizing center, centrosomes play a key role in establishing mitotic bipolar spindles that secure correct transmission of genomic content. For the fidelity of cell division, centrosome number must be strictly controlled by duplicating only once per cell cycle. Proper levels of centrosome proteins are shown to be critical for normal centrosome number and function. Overexpressing core centrosome factors leads to extra centrosomes, while depleting these factors results in centrosome duplication failure. In this regard, protein turnover by the ubiquitin-proteasome system provides a vital mechanism for the regulation of centrosome protein levels. Here, we report that FZR-1, the Caenorhabditis elegans homolog of Cdh1/Hct1/Fzr, a coactivator of the anaphase promoting complex/cyclosome (APC/C), an E3 ubiquitin ligase, functions as a negative regulator of centrosome duplication in the C. elegans embryo. During mitotic cell division in the early embryo, FZR-1 is associated with centrosomes and enriched at nuclei. Loss of fzr-1 function restores centrosome duplication and embryonic viability to the hypomorphic zyg-1(it25) mutant, in part, through elevated levels of SAS-5 at centrosomes. Our data suggest that the APC/CFZR-1 regulates SAS-5 levels by directly recognizing the conserved KEN-box motif, contributing to proper centrosome duplication. Together, our work shows that FZR-1 plays a conserved role in regulating centrosome duplication in C. elegans.
Preparation of 2-Alkyl- and 2-Acylpropenals from 5-(Trifluoromethanesulfonyloxy)-4H-1,3-dioxin: A Versatile Acrolein α-Cation Synthon

Abstract 5-(Trifluoromethanesulfonyloxy)-4 H -1,3-dioxin ( 3 ) participates in a variety of nucleophilic substitution reactions with cuprate reagents or in palladium catalyzed cross-coupling reactions to provide 5-substituted-4 H -1,3-dioxins 5 . Upon thermolysis, these compounds undergo facile retrocycloaddition reactions to generate the corresponding 2-substituted acroleins which, if necessary, can be trapped in situ with dienes or heterodienophiles. In particular, the heretofore unknown 2-acylacroleins can be generated using this methodology and trapped with enol ethers to afford 5-acyl-3,4-dihydro-2 H -pyrans ( 6g , h ), a substructural unit common to many natural products.
Thermal decomposition of 3,3,5‐trisubstituted‐4,4‐dimethyl‐4,5‐dihydro‐5‐hydroperoxy‐3H‐pyrazoles: Route to β,γ‐unsaturated ketones

The thermal decomposition of a series of cyclic α-azo hydroperoxides (3,3,5-R1, R2, R3-4,4-dimethyl-4,5-dihydro-5-hydroperoxy-3H-pyrazoles; 2a R1 = R2 = R3 = Ph; 2b R1 = R3 = Ph, R2 = Me; 2c R1 = R3 = p-Anisyl, R2 = Me; 2d R1 = R2 = Me, R3 = Ph; 2e R1 = R3 = Me, R2 = Ph), synthesized by oxidation of the corresponding 3,4-dihydro-2H-pyrazoles, proceeded smoothly with evolution of nitrogen. The relative stability series was found to be 2a > 2c ≈ 2b > 2d > 2e. For 2a, the products were 1,4,4-triphenyl-2,2-dimethyl-1-propanone and 1,1-dimethyl-2,2-diphenylethylene. For 2b-e, β,γ-unsaturated ketones [R1-C(= CH2)-CMe2-C(= O)R3, 5a-d] were obtained as the major products in ∼60% yield from the thermolyses. The products are consistent with a free-radical mechanism involving initial homolysis of the O-O bond followed by loss of nitrogen to yield a free-radical beta to the carbonyl group. For 2a, β-scission and hydrogen-atom abstraction of the hydroperoxy proton by the β-keto radical (induced decomposition) are the major pathways leading to products. For 2b-c, abstraction of a γ-hydrogen atom of the β-keto radicals by hydroxy radical accounts for the formation of the β,γ-unsaturated compounds as the major product.
Locally Localized Gravity

We study the fluctuation spectrum of linearized gravity around non-fine-tuned branes. We focus on the case of an AdS4 brane in AdS5. In this case, for small cosmological constant, the warp factor near the brane is essentially that of a Minkowski brane. However, far from the brane, the metric differs substantially. The space includes the AdS5 boundary, so it has infinite volume. Nonetheless, for sufficiently small AdS4 cosmological constant, there is a bound state graviton in the theory, and four-dimensional gravity is reproduced. However, it is a massive bound state that plays the role of the four-dimensional graviton.
Resilience to oxidative and nitrosative stress is mediated by the stressosome, RsbP and SigB in Bacillus subtilis

A bacterium's ability to thrive in the presence of multiple environmental stressors simultaneously determines its resilience. We showed that activation of the SigB-controlled general stress response by mild environmental or energy stress provided significant cross-protection to subsequent lethal oxidative, disulfide and nitrosative stress in Bacillus subtilis. SigB activation is mediated via the stressosome and RsbP, the main conduits of environmental and energy stress, respectively. Cells exposed to mild environmental stress while lacking the major stressosome components RsbT or RsbRA were highly sensitive to subsequent oxidative stress, whereas rsbRB, rsbRC, rsbRD, and ytvA null mutants showed a spectrum of sensitivity, confirming their redundant roles and suggesting they could modulate the signals generated by environmental or oxidative stress. By contrast, cells encountering stationary phase stress required RsbP but not RsbT to survive subsequent oxidative stress. Interestingly, optimum cross-protection against nitrosative stress caused by sodium nitropruside required SigB but not the known regulators, RsbT and RsbP, suggesting an additional and as yet uncharacterized route of SigB activation independent of the known regulators. Together, these results provide mechanistic information on how B. subtilis promotes enhanced resistance against lethal oxidative stress during mild environmental and energy stress conditions.
Persistence of antibiotic resistance plasmids in bacterial biofilms

The emergence and spread of antibiotic resistance is a crisis in health care today. Antibiotic resistance is often horizontally transferred to susceptible bacteria by means of multidrug resistance plasmids that may or may not persist in the absence of antibiotics. Because bacterial pathogens often grow as biofilms, there is a need to better understand the evolution of plasmid persistence in these environments. Here we compared the evolution of plasmid persistence in the pathogen Acinetobacter baumannii when grown under antibiotic selection in biofilms versus well-mixed liquid cultures. After 4 weeks, clones in which the plasmid was more stably maintained in the absence of antibiotic selection were present in both populations. On average plasmid persistence increased more in liquid batch cultures, but variation in the degree of persistence was greater among biofilm-derived clones. The results of this study show for the first time that the persistence of MDR plasmids improves in biofilms.
Enantioselective diethylzinc additions to aldehydes catalyzed by chiral relay ligands

Abstract A new pyrazole ligand system incorporating fluxional chirality was found to catalyze the addition of diethylzinc to aldehydes giving rise to the corresponding secondary alcohol products in excellent yields (74–99%) with moderate to high enantioselectivities (46–93%). The size of the fluxional group on the ligand correlated with the level of enantioselectivity of the product.
K4AU(TLSN3) : A NOVEL ZINTL PHASE WITH AN ANIONIC CHAIN

Reactions of the component elements at 1050 °C and then 400 °C in Ta containers generate the black title phase in good yield. Single-crystal X-ray characterization (monoclinic, C2/c, Z = 4, a = 15....
Sequential Annulation in Molecular Construction. A Short, Stereocontrolled Synthesis of (±)‐Hirsutene

A total synthesis of (±)-hirsutene has been achieved in 9 steps and in 14% overall yield via a twofold cycloadditive scheme that utilizes 4,4-dimethylcyclopentene, 1-(trimethylsilyloxy)butadiene, and ethylene as the three key building blocks.
Enantioselective Synthesis of 12-epi-PGF2α and 12,15-diepi-PGF2α

An enantioselective synthesis of 12-epi-PGF2α (3) and 12,15-diepi-PGF2α (4), PG-like compounds that are probably generated in vivo by nonenzymatic, free-radical-induced peroxidation of arachidonic acid, has been achieved starting from the commercially available Corey lactone (9). The key strategy involves SmI2 reduction of the γ,δ-epoxy-α,β-unsaturated ester 7, followed by in situ trapping with hexanal; subsequent hydrogenation and decarboxylation affords the stereoselective construction of the lower side chain. This new method is expected to provide a convenient access to various PG-like isoprostanes derived from oxidation of arachidonic acid and cis-4,7,10,13,16,19-docosahexaenoic acid.
Synthesis of substituted N-hydroxyureas via the in situ generation of t-butoxy isocyanate

Abstract Treatment of primary and secondary amines with tert -butylmesitylenesulfonoxycarbamate and a base afforded tert -butoxyurea, which when treated with an acid ultimately yielded substituted N -hydroxyureas. It is proposed that this proceeded via the generation of t -butoxy isocyanate in situ. This method allows for the synthesis of both mono and disubstituted N -hydroxyureas.
Synthesis of tertiary alcohols via the use of the allyldimethylsilyl moiety as a latent hydroxyl group in the Kumada-Fleming-Tamao reaction.

Abstract The phenyldimethylsilyl to hydroxyl transformation fails in the cases where a cyclic tertiary carbon center is involved as was observed in the synthesis of phorbol C-ring models. An alternate functionality in the form of allyldimethyl silane (ADMS) is found to work well in these and other cases involving tertiary centers. With proper choice of reagents, the ADMS group can be employed as a latent alcohol in systems containing ketones, esters, arenes, and vinyl groups.
Portable and Error-Free DNA-Based Data Storage

DNA-based data storage is an emerging nonvolatile memory technology of potentially unprecedented density, durability, and replication efficiency. The basic system implementation steps include synthesizing DNA strings that contain user information and subsequently retrieving them via high-throughput sequencing technologies. Existing architectures enable reading and writing but do not offer random-access and error-free data recovery from low-cost, portable devices, which is crucial for making the storage technology competitive with classical recorders. Here we show for the first time that a portable, random-access platform may be implemented in practice using nanopore sequencers. The novelty of our approach is to design an integrated processing pipeline that encodes data to avoid costly synthesis and sequencing errors, enables random access through addressing, and leverages efficient portable sequencing via new iterative alignment and deletion error-correcting codes. Our work represents the only known random access DNA-based data storage system that uses error-prone nanopore sequencers, while still producing error-free readouts with the highest reported information rate/density. As such, it represents a crucial step towards practical employment of DNA molecules as storage media.
The Shape of the Edge of a Leaf

Leaves and flowers frequently have a characteristic rippling pattern at their edges. Recent experiments found similar patterns in torn plastic. These patterns can be reproduced by imposing metrics upon thin sheets. The goal of this paper is to discuss a collection of analytical and numerical results for the shape of a sheet with a non-flat metric. First, a simple condition is found to determine when a stretched sheet folded into a cylinder loses axial symmetry, and buckles like a flower. General expressions are next found for the energy of stretched sheets, both in forms suitable for numerical investigation, and for analytical studies in the continuum. The bulk of the paper focuses upon long thin strips of material with a linear gradient in metric. In some special cases, the energy-minimizing shapes of such strips can be determined analytically. Euler–Lagrange equations are found which determine the shapes in general. The paper closes with numerical investigations of these equations.
Synthesis of 1,4,5-trisubstituted-1,2,3-triazoles by copper-catalyzed cycloaddition-coupling of azides and terminal alkynes

Abstract Primary, secondary, and aromatic azides undergo 1,3 dipolar cycloaddition-coupling with an excess of alkyne in the presence of Cu(CH 3 CN) 4 PF 6 as catalyst, N , N , N ′-trimethylethylenediamine as ligand, molecular oxygen, and 4-methoxymorpholine N -oxide (NMO) as co-oxidant to afford 1,4,5-trisubstituted-1,2,3-triazoles.
Spongiabutenolides A – D: Minor γ-hydroxybutenolide diterpenoids from a Philippines Spongia sp.

Abstract Four novel diterpenoids, spongiabutenolides A – D (2–5), all of which contain a γ-hydroxybutenolide moiety, have been isolated from a Philippines marine sponge of the genus Spongia. The structures of spongiabutenolides A – D (2–5) and the methyl esters 6 and 7 were elucidated by interpretation of spectral data. Spongiabuteonolide A (2) was synthesized from spongia-13(16),14-diene-19-oic acid (1) by singlet oxygen oxidation.
Pseudopeptide synthesis of a pentaazamacrocycle containing two trans-fused cyclohexane rings

Abstract The synthesis of a bis-cyclohexyl-fused pentaazamacrocycle via head-to-tail pseudopeptide cyclization chemistry is described. The bis-cyclohexyl-fused cyclic pseudopeptide 11 displays intramolecular hydrogen bonding which has been characterized by variable temperature NMR spectroscopy and X-Ray Crystallography.
C2-SYMMETRIC COPPER(II) COMPLEXES AS CHIRAL LEWIS ACIDS. ENANTIOSELECTIVE CATALYSIS OF THE GLYOXYLATE-ENE REACTION

The development of enantioselective Lewis acid catalyzed carbonyl addition reactions of π-nucleophiles such as enolsilanes and allylstannanes is a topic of current interest.1 The extension of this general process to include simple olefinic nucleophiles via the carbonyl-ene reaction2 has important practical implications. In this context, Mikami and Nakai have reported a catalytic enantioselective ene reaction with glyoxylate esters;3 however, due to the limiting reactivity of the catalyst-glyoxylate complex,4 only nucleophilic 1,1-disubstituted olefins may be employed. We have recently reported that bidentate bis(oxazolinyl) (box) Cu(II) complexes 1-3 are effective enantioselective catalysts in Diels-Alder5 and aldol reactions6 with substrates that can participate in catalyst chelation. In this study, we demonstrate that
A Formal Treatment of Backdoored Pseudorandom Generators.

We provide a formal treatment of backdoored pseudorandom generators (PRGs). Here a saboteur chooses a PRG instance for which she knows a trapdoor that allows prediction of future (and possibly past) generator outputs. This topic was formally studied by Vazirani and Vazirani, but only in a limited form and not in the context of subverting cryptographic protocols. The latter has become increasingly important due to revelations about NIST’s backdoored Dual EC PRG and new results about its practical exploitability using a trapdoor. We show that backdoored PRGs are equivalent to public-key encryption schemes with pseudorandom ciphertexts. We use this equivalence to build backdoored PRGs that avoid a well known drawback of the Dual EC PRG, namely biases in outputs that an attacker can exploit without the trapdoor. Our results also yield a number of new constructions and an explanatory framework for why there are no reported observations in the wild of backdoored PRGs using only symmetric primitives. We also investigate folklore suggestions for countermeasures to backdoored PRGs, which we call immunizers. We show that simply hashing PRG outputs is not an effective immunizer against an attacker that knows the hash function in use. Salting the hash, however, does yield a secure immunizer, a fact we prove using a surprisingly subtle proof in the random oracle model. We also give a proof in the standard model under the assumption that the hash function is a universal computational extractor (a recent notion introduced by Bellare, Tung, and Keelveedhi).
Reactive Oxygen Species Regulate the Inflammatory Function of NKT Cells Through Promyelocytic Leukemia Zinc Finger

Reactive oxygen species (ROS) are byproducts of aerobic metabolism and contribute to both physiological and pathological conditions as second messengers. ROS are essential for activation of T cells, but how ROS influence NKT cells is unknown. In the present study, we investigated the role of ROS in NKT cell function. We found that NKT cells, but not CD4 or CD8 T cells, have dramatically high ROS in the spleen and liver of mice but not in the thymus or adipose tissues. Accordingly, ROS-high NKT cells exhibited increased susceptibility and apoptotic cell death with oxidative stress. High ROS in the peripheral NKT cells were primarily produced by NADPH oxidases and not mitochondria. We observed that sorted ROS-high NKT cells were enriched in NKT1 and NKT17 cells, whereas NKT2 cells were dominant in ROS-low cells. Furthermore, treatment of NKT cells with antioxidants led to reduced frequencies of IFN-γ- and IL-17-expressing cells, indicating that ROS play a role in regulating the inflammatory function of NKT cells. The transcription factor promyelocytic leukemia zinc finger (PLZF) seemed to control the ROS levels. NKT cells from adipose tissues that do not express PLZF and those from PLZF haplodeficient mice have low ROS. Conversely, ROS were highly elevated in CD4 T cells from mice ectopically expressing PLZF. Thus, our findings demonstrate that PLZF controls ROS levels, which in turn governs the inflammatory function of NKT cells.
Asymmetric epoxidation of allyl alcohol derivatives by ω‐hydroxylase from Pseudomonas oleovorans

This paper described the application of non-heme monooxygenase system from Pseudomonas oleovorans to the syntheses of chiral 3-(benzyloxy)-, 3-(allyloxy)-, 3-(butyloxy)- and 3-(aryloxy)-1,2-epoxypropanes (6) from their corresponding allyl alcohol derivatives. The epoxides were determined to be R forms with good enantiomeric excess. The specificities of the enzymatic epoxidation of olefines and hydroxylation of the radical probe trans-2-phenyl-1-methylcyclopropane were discussed with regard to the reaction mechanism.
Oxadiazinones as chiral auxiliaries: diastereoselective aldol addition reactions of N3-glycolyl-3,4,5,6-tetrahydro-2H-1,3,4-oxadiazin-2-ones

Abstract Asymmetric aldol reactions have been conducted with a series of N 3 -glycolyl-3,4,5,6-tetrahydro-2 H -1,3,4-oxadiazin-2-ones derived from (1 R ,2 S )-ephedrine. These reactions afford the non-Evans syn -adducts in 43–97% yield and diastereoselectivities ranging from 62:38 to 99:1. Oxadiazinone substrates substituted with either the phenoxyacetyl or p -methoxyphenoxyacetyl groups gave the best results whereas the methoxyacetyl substituted oxadiazinone afforded diastereoselectivities that were modest.
Dynamic Alterations of Retinal EphA5 Expression in Retinocollicular Map Plasticity

The topographically ordered retinocollicular projection is an excellent system for studying the mechanism of axon guidance. Gradients of EphA receptors in the retina and ephrin-As in the superior colliculus (SC) pattern the anteroposterior axis of the retinocollicular map, but whether they are involved in map plasticity after injury is unknown. Partial damage to the caudal SC at birth creates a compressed, complete retinotopic map in the remaining SC without affecting visual response properties. Previously, we found that the gradient of ephrin-A expression in compressed maps is steeper than normal, suggesting an instructive role in compression. Here we measured EphA5 mRNA and protein levels after caudal SC damage in order to test the hypothesis that changes in retinal EphA5 expression occur that are complementary to the changes in collicular ephrin-A expression. We find that the nasotemporal gradient of EphA5 receptor expression steepens in the retina and overall expression levels change dynamically, especially in temporal retina, supporting the hypothesis. This change in receptor expression occurs after the change in ephrin-A ligand expression. We propose that changes in the retinal EphA5 gradient guide recovery of the retinocollicular projection from early injury. This could occur directly through the change in EphA5 expression instructing retino-SC map compression, or through ephrin-A ligand signaling instructing a change in EphA5 receptor expression that in turn signals the retinocollicular map to compress. Understanding what molecular signals direct compensation for injury is essential to developing rehabilitative strategies and maximizing the potential for recovery.
Intermolecular Ketene–Alkene [2+2] Cycloadditions: The Significance of ­Lewis Acid Promoted Variants

Ketene–alkene [2+2] cycloadditions are an important class of reactions for chemical synthesis. These processes were exclusively carried out under thermal conditions, which ultimately lead to limitations regarding scope and stereoselectivity. Reviewed herein are recently developed Lewis acid promoted ketene–alkene [2+2] cycloadditions that address several of the problems known to plague these reactions.
Recent Developments in Nitrone Chemistry: Some Novel Transformations

Despite the long history of nitrone chemistry, novel transformations of nitrones continue to be discovered. This article describes some recent breakthroughs in the development of new transformations of nitrones. These new reactions include formal [3+3] cycloaddition of nitrones and vinylcarbenes to give 3,6-dihydro-1,2-oxazines, tandem cyclization–[3+3] cycloaddition of ­nitrones and enynones to give furo[3,4-d][1,2]oxazines, [2+2+3] cycloaddition of nitrones and 1,6-enynes to give tricyclic 1,2-ox­azepanes, reaction of nitrones and 2-azido acrylates to form 1,2,4,5-tetra­substituted imidazoles, and reactions of α,β-unsaturated N-aryl ketonitrones and activated alkynes to generate C3-quaternary indolenines.
The first synthesis of a noreremophilane isolated from the roots of Ligularia przewalskii

The total synthesis of a natural product noreremophilane has been achieved in just three steps from readily available starting materials. A highly stereo- and regio-selective Diels–Alder reaction was the key step in our synthesis.
Synthesis of 3,5-disubstituted 1,2,4-triazoles containing trimethoxyphenyl groups : potential antagonists of platelet activating factor

In an effort to develop a new class of Platelet Activating Factor antagonists, 3,5-disubstituted 1,2,4-triazoles containing trimethoxyphenyl groups have been synthesized. The synthesis of symmetrical triazoles 5 and 6, as well as two methods of synthesizing unsymmetrical triazole 7, are reported.
STatistical Inference Relief (STIR) feature selection.

MOTIVATION Relief is a family of machine learning algorithms that uses nearest-neighbors to select features whose association with an outcome may be due to epistasis or statistical interactions with other features in high-dimensional data. Relief-based estimators are non-parametric in the statistical sense that they do not have a parameterized model with an underlying probability distribution for the estimator, making it difficult to determine the statistical significance of Relief-based attribute estimates. Thus, a statistical inferential formalism is needed to avoid imposing arbitrary thresholds to select the most important features. We reconceptualize the Relief-based feature selection algorithm to create a new family of STatistical Inference Relief (STIR) estimators that retains the ability to identify interactions while incorporating sample variance of the nearest neighbor distances into the attribute importance estimation. This variance permits the calculation of statistical significance of features and adjustment for multiple testing of Relief-based scores. Specifically, we develop a pseudo t-test version of Relief-based algorithms for case-control data. RESULTS We demonstrate the statistical power and control of type I error of the STIR family of feature selection methods on a panel of simulated data that exhibits properties reflected in real gene expression data, including main effects and network interaction effects. We compare the performance of STIR when the adaptive radius method is used as the nearest neighbor constructor with STIR when the fixed-k nearest neighbor constructor is used. We apply STIR to real RNA-Seq data from a study of major depressive disorder and discuss STIR's straightforward extension to genome-wide association studies. AVAILABILITY AND IMPLEMENTATION Code and data available at http://insilico.utulsa.edu/software/STIR. SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
Peer Bargaining and Productivity in Teams: Gender and the Inequitable Division of Pay

Problem description: A recent trend in personnel operations is to reduce hierarchy and allow employee teams to self-manage tasks, responsibilities, and rewards. Yet, we know little about how this a...
Active learning from weak and strong labelers

An active learner is given a hypothesis class, a large set of unlabeled examples and the ability to interactively query labels to an oracle of a subset of these examples; the goal of the learner is to learn a hypothesis in the class that fits the data well by making as few label queries as possible. This work addresses active learning with labels obtained from strong and weak labelers, where in addition to the standard active learning setting, we have an extra weak labeler which may occasionally provide incorrect labels. An example is learning to classify medical images where either expensive labels may be obtained from a physician (oracle or strong labeler), or cheaper but occasionally incorrect labels may be obtained from a medical resident (weak labeler). Our goal is to learn a classifier with low error on data labeled by the oracle, while using the weak labeler to reduce the number of label queries made to this labeler. We provide an active learning algorithm for this setting, establish its statistical consistency, and analyze its label complexity to characterize when it can provide label savings over using the strong labeler alone.
A New Approach for Steady-State Analysis of a Hybrid ac-dc Microgrid

The dc grid became more popular, by emerging the distributed generations (DGs). Despite this popularity, the dc grid is not yet widely used because the majority of loads in a power system are ac, which means the ac grid is still the dominant grid in the power system. Therefore, the concept of a hybrid ac-dc microgrid was emerged because of this contradiction. Hybrid ac-dc microgrid was introduced in order to exploit the benefits of both ac and dc microgrids. However, the combination of both ac and dc microgrids will add more complexity to the network. Because in all studies for hybrid ac-dc microgrid, such as steady-state analysis or dynamic study, two sets of equations should be considered and solved either separately or simultaneously, the solutions that were presented before. These solutions increase the time of simulation and operation.In this paper, a novel procedure for steady-state analysis of a general hybrid ac-dc microgrid is proposed. In this technique, the dc microgrids will be transferred to the ac side by proposing two lemmas and then the whole grid will be analyzed as one ac network. It will be proved that not only the new ac grid has the same power flow result with the initial topology of the ac-dc microgrid, but also the simulation time of the proposed method is less than the other existing methods.
Permutation invariant proper polyhedral cones and their Lyapunov rank

Abstract The Lyapunov rank of a proper cone K in a finite dimensional real Hilbert space is defined as the dimension of the space of all Lyapunov-like transformations on K, or equivalently, the dimension of the Lie algebra of the automorphism group of K. This (rank) measures the number of linearly independent bilinear relations needed to express a complementarity system on K (that arises, for example, from a linear program or a complementarity problem on the cone). Motivated by the problem of describing spectral/proper cones where the complementarity system can be expressed as a square system (that is, where the Lyapunov rank is greater than equal to the dimension of the ambient space), we consider proper polyhedral cones in R n that are permutation invariant. For such cones we show that the Lyapunov rank is either 1 (in which case, the cone is irreducible) or n (in which case, the cone is isomorphic to R + n ). In the latter case, we show that the corresponding spectral cone is isomorphic to a symmetric cone.
A Framework for Partial Secrecy

We consider theoretical limits of partial secrecy in a setting where an eavesdropper attempts to causally reconstruct an information sequence with low distortion based on an intercepted transmission and the past of the sequence. The transmitter and receiver have limited secret key at their disposal but not enough to establish perfect secrecy with a one-time pad. From another viewpoint, the eavesdropper is acting as an adversary, competing in a zero-sum repeated game against the sender and receiver of the secrecy system. In this case, the information sequence represents a sequence of actions, and the distortion function captures the payoff of the game. We give an information theoretic region expressing the tradeoff between secret key rate and max-min distortion for the eavesdropper. We also simplify this characterization to a linear program. As an example, we discuss how to optimally use secret key to hide Bernoulli-p bits from an eavesdropper so that they incur maximal Hamming distortion.
An efficient algorithm for computing interventional distributions in latent variable causal models

Probabilistic inference in graphical models is the task of computing marginal and conditional densities of interest from a factorized representation of a joint probability distribution. Inference algorithms such as variable elimination and belief propagation take advantage of constraints embedded in this factorization to compute such densities efficiently. In this paper, we propose an algorithm which computes interventional distributions in latent variable causal models represented by acyclic directed mixed graphs (ADMGs). To compute these distributions efficiently, we take advantage of a recursive factorization which generalizes the usual Markov factorization for DAGs and the more recent factorization for ADMGs. Our algorithm can be viewed as a generalization of variable elimination to the mixed graph case. We show our algorithm is exponential in the mixed graph generalization of treewidth.
Non-asymptotic analysis of tangent space perturbation

Constructing an efficient parameterization of a large, noisy data set of points lying close to a smooth manifold in high dimension remains a fundamental problem. One approach consists in recovering a local parameterization using the local tangent plane. Principal component analysis (PCA) is often the tool of choice, as it returns an optimal basis in the case of noise-free samples from a linear subspace. To process noisy data samples from a nonlinear manifold, PCA must be applied locally, at a scale small enough such that the manifold is approximately linear, but at a scale large enough such that structure may be discerned from noise. Using eigenspace perturbation theory and non-asymptotic random matrix theory, we study the stability of the subspace estimated by PCA as a function of scale, and bound (with high probability) the angle it forms with the true tangent space. By adaptively selecting the scale that minimizes this bound, our analysis reveals an appropriate scale for local tangent plane recovery. We also introduce a geometric uncertainty principle quantifying the limits of noise-curvature perturbation for stable recovery. With the purpose of providing perturbation bounds that can be used in practice, we propose plug-in estimates that make it possible to directly apply the theoretical results to real data sets.