cssi/SciSciGPT-SciSciNet huggingface dataset:
Application of vinyl tris(trimethylsilyl)germanes in Pd-catalyzed couplings.

The oxidative treatment of vinyltris(trimethylsilyl)germanes with hydrogen peroxide (NaOH/H2O/THF) or tert-butyl peroxide (KH/THF) generates reactive germanol or germanoxane species that undergo Pd-catalyzed cross-couplings with aryl and alkenyl halides and aryl triflates in the presence of Pd(PPh3)4. Vinylgermanes having either a conjugated or isolated double bond serve as versatile transmetalation reagents. The E-germanes undergo coupling with retention of stereochemistry under aqueous and anhydrous conditions, while coupling of Z-germanes occurs with less stereoselectivity to produce a mixture of E/Z products.
A logic approach to modelling nomenclatural change

We utilize an Answer Set Programming (ASP) approach to show that the principles of nomenclature are tractable in computational logic. To this end we design a hypothetical, 20 nomenclatural taxon use case, with starting conditions that embody several overarching principles of the International Code of Zoological Nomenclature, including Binomial Nomenclature, Priority, Coordination, Homonymy, Typification and the structural requirement of Gender Agreement. The use case ending conditions are triggered by the reinterpretation of the diagnostic features of one of 12 type specimens anchoring the corresponding species-level epithets. Permutations of this child-to-parent reassignment action lead to 36 alternative scenarios, where each scenario requires a set of 1–14 logically contingent nomenclatural emendations. We show that an ASP transition system approach can correctly infer the Code-mandated changes for each scenario, and visually output the ending conditions. The results provide a foundation for further developing logic-based nomenclatural change optimization and validation services, which could be applied in global nomenclatural registries. More generally, logic explorations of nomenclatural and taxonomic change scenarios provide a novel means of assessing design biases inherent in the principles of nomenclature, and can therefore inform the design of future, big data-compatible identifier systems that recognize and mitigate these constraints.
Benzannulation reactions of Fischer carbene complexes for the synthesis of indolocarbazoles

Abstract The synthesis of indolocarbazoles was achieved via photochemical and thermal annulation reactions of chromium Fischer carbene complexes. This methodology allows for facile incorporation of hydrogen bonding functionality which complements the pharmacophore contained within bioactive indolocarbazole natural products.
Synthesis of N-phosphoryl amino acids using bis(9-fluorenylmethyl)phosphite

Bis(9-fluorenylmethyl)phosphite (BFMP) was found to be an effective reagent for the N-phosphorylation of various amino acid methyl esters. BFMP was prepared from N,N-diisopropyl phosphoramidous dichloride in a one-pot two-step reaction and was obtained as a crystalline solid. N-Phosphorylation of the methyl esters of seven representative amino acids with BFMP was high-yielding and generally resulted in crystalline products. Complete deprotection of both the 9-fluorenylmethylphosphosphate esters and the amino acid methyl esters was accomplished concomitantly with LiOH to give N-phosphoryl amino acids.
Utilization of Potassium Vinyltrifluoroborate in the Development of a 1,2-Dianion Equivalent

Previous studies of orthogonally reactive dibora species led to the discovery of a unique reactivity pattern associated with potassium vinyltrifluoroborate. Upon hydroboration, the vinyltrifluoroborate generates a 1,2-diboraethane, which is distinct from the 1,1-dibora intermediates generated when traditional alkenyldialkylboron species undergo hydroboration. The 1,2-dianion equivalent thus generated can be envisioned as a building block for the linkage of two different electrophiles via palladium-catalyzed Suzuki−Miyaura cross-couplings.
Syntheses of Nitrogen-Containing Heterocycles via Palladium-Catalyzed Intramolecular Dehydrogenative C–H Amination

This article traces the development of catalytic, intramolecular dehydrogenative C–H amination (IDCA) reactions. Over the last 10 years, effective syntheses of carbazoles, indolines and oxindoles via palladium-catalyzed sp2 intramolecular dehydrogenative C–H amination reactions have been realized. While the corresponding amination reactions of sp3 C–H bonds are more challenging, syntheses of pyrrolidines, azetidines, β-lactams and even aziridines via this manifold have been reported. 1 Introduction 2 Intramolecular Aminations of C(sp2)–H Bonds 3 Intramolecular Aminations of C(sp3)–H Bonds 4 Conclusion
Hawkmoth flight in the unsteady wakes of flowers.

ABSTRACT Flying animals maneuver and hover through environments where wind gusts and flower wakes produce unsteady flow. Although both flight maneuvers and aerodynamic mechanisms have been studied independently, little is known about how these interact in an environment where flow is already unsteady. Moths forage from flowers by hovering in the flower9s wake. We investigated hawkmoths tracking a 3D-printed robotic flower in a wind tunnel. We visualized the flow in the wake and around the wings and compared tracking performance with previous experiments in a still-air flight chamber. As in still air, moths flying in the flower wake exhibit near-perfect tracking at the low frequencies at which natural flowers move. However, tracking in the flower wake results in a larger overshoot between 2 and 5 Hz. System identification of flower tracking reveals that moths also display reduced-order dynamics in wind compared with still air. Smoke visualization of the flower wake shows that the dominant vortex shedding corresponds to the same frequency band as the increased overshoot. Despite these large effects on tracking dynamics in wind, the leading edge vortex (LEV) remains bound to the wing throughout the wingstroke and does not burst. The LEV also maintains the same qualitative structure seen in steady air. Persistence of a stable LEV during decreased flower tracking demonstrates the interplay between hovering and maneuvering.
Supersymmetric partners of oblique corrections

Abstract We discuss a potential new probe of supersymmetric physics. In particular, we discuss the possibility of measuring hard supersymmetry violation which occurs at one loop through “super-oblique” corrections to the gauge and gaugino propagators. In models with heavy scalar partners, or with many gauge-charged particles which participate in supersymmetry breaking, these effects can be substantial due to logarithmic and multiplicity factor enhancements.
Trimethylaluminum-triflimide complexes for the catalysis of highly hindered Diels-Alder reactions.

Two catalysts, Me2AlNTf2 and MeAl(NTf2)2, derived from the mixing of trimethylaluminum with triflimide, proved to be highly effective catalysts in hindered Diels–Alder reactions, generating the desired Diels–Alder cycloadducts from both hindered 2-silyloxydienes and hindered dienophiles. Thus reaction of 1 with 2 afforded the hindered cycloadduct 4 in excellent yield in 0.5–1.5 h at −40 °C.
Synthesis of 6-deoxy-6,6-difluoro-α-d-glucopyranosyl fluoride

Abstract The synthesis of 6-deoxy-6,6-difluoro-α- d -glucopyranosyl fluoride from the benzyl-protected methylglucoside was accomplished in six steps.
Novel CRISPR/Cas9 gene drive constructs reveal insights into mechanisms of resistance allele formation and drive efficiency in genetically diverse populations

A functioning gene drive system could fundamentally change our strategies for the control of vector-borne diseases by facilitating rapid dissemination of transgenes that prevent pathogen transmission or reduce vector capacity. CRISPR/Cas9 gene drive promises such a mechanism, which works by converting cells that are heterozygous for the drive construct into homozygotes, thereby enabling super-Mendelian inheritance. Although CRISPR gene drive activity has already been demonstrated, a key obstacle for current systems is their propensity to generate resistance alleles, which cannot be converted to drive alleles. In this study, we developed two CRISPR gene drive constructs based on the nanos and vasa promoters that allowed us to illuminate the different mechanisms by which resistance alleles are formed in the model organism Drosophila melanogaster. We observed resistance allele formation at high rates both prior to fertilization in the germline and post-fertilization in the embryo due to maternally deposited Cas9. Assessment of drive activity in genetically diverse backgrounds further revealed substantial differences in conversion efficiency and resistance rates. Our results demonstrate that the evolution of resistance will likely impose a severe limitation to the effectiveness of current CRISPR gene drive approaches, especially when applied to diverse natural populations.
An example of a novel formation of an oxepin

A novel formation of an oxepin, namely 9,10,11,12-tetrafluoro-5,6-dihydrobenzo[b]naphth[2,1-f]oxepin (5), starting from pentafluoroacetophenone and 1-tetralone is described. Also, the same synthesis using 1-indanone affords a very different ring system namely 1,2,3,4-tetrafluoro-5,11b-dihydro-7H-benzo[c]fluoren-7-one (10). Both synthesis undergo an intramolecular nucleophilic substitution of an ortho-fluorine. In one case, the oxygen displaces the fluorine to afford the oxepin 5 and the other a carbon is used as the nucleophile to give the polycyclic ring system 10.
New four-component condensations leading to 2,4,5-trisubstituted oxazoles☆

Abstract A one-pot reaction leading to the title compounds has been developed based on the in situ acylation and hydroxyarylation of 5-aminooxazoles at the 4-position of the heterocycle.
Transformations of N-Substituted Benzotriazoles into the Corresponding Carbanions by C−Benzotriazole Bond Scission‡

Various N-substituted benzotriazoles are transformed, by scission of the C-benzotriazole bond, into the corresponding carbanions by treatment with lithium. Thus, N-(diphenylmethyl)benzotriazole (1), N-benzylbenzotriazole (6), and N-allylbenzotriazole (10) all gave carbanions that reacted with diverse electrophiles to afford the corresponding products in good yields. This new methodology was successfully utilized to convert N-benzylbenzotriazole (6) and N-allylbenzotriazole (10) into dianion synthons by a sequential lithiation and reductive coupling and bis(benzotriazolyl)toluene (18) by double reductive couplings, demonstrating the synthetic potential of the present methodology.
A palladium-catalyzed regio- and stereoselective four-component coupling reaction

Pd(PPh3)4 catalytically assembles sulfenamide, alkyne, carbon monoxide, and diphenyl diselenide regio- and stereoselectively in a one-pot four-component coupling reaction to yield (Z)-β-selenyl acrylamides. The reaction proceeds in good to excellent yields (60−95%) and is tolerant of a range of functional groups on both the nitrogen of the sulfenamide and the alkyne. Moderate selectivities ranging from 4:1 to 7:1 β-selenyl to β-sulfenyl acrylamide have been observed despite the initial concentration of 2:1 selenium to sulfur in the reaction. The chalcogeno selectivity was found to depend directly on CO pressure; increased pressure decreased selectivity for selenium over sulfur.
Synthesis, structure, and characterization of a new one-dimensional tellurite phosphate, Ba2TeO(PO4)2

Abstract A new one-dimensional tellurite phosphate, Ba2TeO(PO4)2 has been synthesized by standard solid-state reaction techniques using BaCO3, TeO2, and (NH4)H2PO4 as reagents. The structure of Ba2TeO(PO4)2 was determined by single-crystal X-ray diffraction. Ba2TeO(PO4)2 crystallizes in the triclinic space group P-1 (No. 2), with a = 6.9461 ( 16 ) A , b = 7.3970 ( 17 ) A , c = 8.887 ( 2 ) A , α = 76.843 ( 4 ) ° , β = 79.933 ( 4 ) ° , γ = 75.688 ( 4 ) ° , V = 427.40 ( 17 ) A 3 , and Z = 2 . Ba2TeO(PO4)2 has a novel one-dimensional chain structure that is composed of PO4 tetrahedra and TeO5 polyhedra. Te4+ cations are in asymmetric coordination environments attributable to their lone pairs. The lone pairs on the Te4+ cations point in the [100] and [−100] direction and interact with the Ba2+ cations. Infrared, Raman, and UV–Vis diffuse reflectance spectroscopy, thermogravimetric analysis, and dipole moment calculations are also presented.
A network modeling approach to elucidate drug resistance mechanisms and predict combinatorial drug treatments in breast cancer

Mechanistic models of within-cell signal transduction networks can explain how these networks integrate internal and external inputs to give rise to the appropriate cellular response. These models can be fruitfully used in cancer cells, whose aberrant decision-making regarding their survival or death, proliferation or quiescence can be connected to errors in the state of nodes or edges of the signal transduction network. Here we present a comprehensive network, and discrete dynamic model, of signal transduction in ER+ breast cancer based on the literature of ER+, HER2+, and PIK3CA-mutant breast cancers. The network model recapitulates known resistance mechanisms to PI3K inhibitors and suggests other possibilities for resistance. The model also reveals known and novel combinatorial interventions that are more effective than PI3K inhibition alone. The use of a logic-based, discrete dynamic model enables the identification of results that are mainly due to the organization of the signaling network, and those that also depend on the kinetics of individual events. Network-based models such as this will play an increasing role in the rational design of high-order therapeutic combinations.
Hydrosilylation of alkynylsilanes utilizing organolanthanide and Group 3 metallocene complexes

Abstract The organolanthanide- and Group 3 metallocene-catalyzed hydrosilylation of alkynylsilanes has been found to provide (Z)-1,1-bis(silyl)alkenes. In particular, Cp*2YMe·THF (1), [CpTMS2YMe]2 (2), and [CpTMS2LuMe]2 (3) were shown to be regioselective for the hydrosilylation of various alkynylsilanes ( Fig. 1 Download : Download high-res image (33KB) Download : Download full-size image Fig. 1 . Lanthanocene complexes. ). The process was evaluated for diverse substitution patterns and functional groups on the pendant alkyl chain. Silyl ethers and halogens are stable to the catalytic process, affording excellent chemo- and regioselectivities. Competition between ‘aryl-directed’ and ‘silyl-directed’ processes was observed upon hydrosilylation of (phenylethynyl)dimethylsilane.
MODE OF ATTACK OF ATOMIC CARBON ON BENZENE RINGS

Reaction of arc generated carbon atoms with tert-butylbenzene, 4, gives 3-methyl-3-phenyl-1-butene, 5, and 1,1-dimethylindane, 6. Labeling studies and isotope effects demonstrate that 5 results from an insertion into a methyl C−H bond followed by 1,2 hydrogen shift while 6 arises from initial ortho C−H insertion followed by intramolecular insertion into a methyl C−H bond. When fluoroboric acid is added to the 77 K matrix of 4 + C, tert-butyltropylium fluoroborate, 18, is formed. Labeling studies indicate that 18 results from initial insertion of C into meta and para C−H bonds of 4 followed by ring expansion to cycloheptatetraenes which are subsequently protonated. The reaction of C with benzene gives similar results, indicating that initial C−H insertion is the preferred mode of attack of atomic carbon on benzene rings.
IMPROVED SYNTHESIS OF bis(2,2,2-TRIFLUOROETHYL) PHOSPHOROCHLORIDATE

(1999). IMPROVED SYNTHESIS OF bis(2,2,2-TRIFLUOROETHYL) PHOSPHOROCHLORIDATE. Organic Preparations and Procedures International: Vol. 31, No. 2, pp. 230-231.
Novel sequence of two base-catalyzed 1,3 proton shifts and [1,2] Wittig rearrangement in the synthesis of 2,4-bis-(trifluoromethyl)-6-phenylpyridine

Abstract The reaction of 1,1,1,5,5,5-hexafluoro-2,4-pentanedione with (R)-phenylglycinol was found to proceed via intermediate formation of (R, 4E, 6Z)-5,7-bis-(trifluoromethyl)-2,3-dihydro-3-phenyl-1,4-oxazepine which further underwent a base-catalyzed 1,3-proton shift reaction followed by [1,2] Wittig rearrangement giving rise to 2,4-bis-(trifluoromethyl)-6-phenylpyridine.
A copper(II)-catalyzed, sequential Michael–aldol reaction for the preparation of 1,2-dihydroquinolines

Abstract A copper(II)-catalyzed, sequential Michael addition-aldol condensation reaction of N-carboxybenzyl-protected aminobenzaldehyde with various α,β-unsaturated N-acyl pyrroles is described. Substrate scope was found to include both aryl and aliphatic N-acyl pyrroles as the Michael acceptors, and isolated product yields as high as 93% were observed. The use of acetonitrile as the reaction solvent proved to be crucial for catalysis, both to function as a labile ligand for copper, as well as an agent to minimize hydrolytic catalyst poisoning.
Combinatorial Approaches to Viral Attenuation

Attenuated viruses have numerous applications, in particular in the context of live viral vaccines. However, purposefully designing attenuated viruses remains challenging, in particular if the attenuation is meant to be resistant to rapid evolutionary recovery. Here we develop and analyze a new attenuation method, promoter ablation, using an established viral model, bacteriophage T7. Ablation of promoters of the two most highly expressed T7 proteins (scaffold and capsid) led to major reductions in transcript abundance of the affected genes, with the effect of the double knockout approximately additive of the effects of single knockouts. Fitness reduction was moderate and also approximately additive; fitness recovery on extended adaptation was partial and did not restore the promoters. The fitness effect of promoter knockouts combined with a previously tested codon deoptimization of the capsid gene was less than additive, as anticipated from their competing mechanisms of action. In one design, the engineering created an unintended consequence that led to further attenuation, the effect of which was studied and understood in hindsight. Overall, the mechanisms and effects of genome engineering on attenuation behaved in a predictable manner. Therefore, this work suggests that the rational design of viral attenuation methods is becoming feasible. IMPORTANCE Live viral vaccines rely on attenuated viruses that can successfully infect their host but have reduced fitness or virulence. Such attenuated viruses were originally developed through trial and error, typically by adaptation of the wild-type virus to novel conditions. That method was haphazard, with no way of controlling the degree of attenuation or the number of attenuating mutations or preventing evolutionary reversion. Synthetic biology now enables rational design and engineering of viral attenuation, but rational design must be informed by biological principles to achieve stable, quantitative attenuation. This work shows that in a model system for viral attenuation, bacteriophage T7, attenuation can be obtained from rational design principles, and multiple different attenuation approaches can be combined for enhanced overall effect.
Discovery of novel pyridinopolyamines with potent antimicrobial activity: deconvolution of mixtures synthesized by solution-phase combinatorial chemistry.

A 1638-member pyridinopolyamine library, consisting of 13 sublibraries of 126 members prepared by a solution-phase approach, was completely deconvoluted from orthogonally protected intermediates by...
Synthesis of 4-alkyl-pyrrolidine-3-carboxylic acid stereoisomers

Abstract All four possible stereoisomers of the 3-carboxyl-4-isopropyl-pyrrolidine (4) were prepared and their stereochemistry was assigned unambiguously.
Formation of Seven-Membered Oxacycles through Ring Expansion of Cyclopropanated Carbohydrates

The cyclopropanation and ring expansion of 4,6-O-(di-tert-butylsilanediyl)-d-glucal (1) to produce oxepanes have been investigated. Using catalytic amounts of TMSOTf and an excess of a silylated nucleophile, a wide range of substituted oxepanes have been synthesized. Good to excellent yields are obtained; however, only modest diastereoselectivity resulted. This new methodology should provide convenient access into the synthesis of optically active oxepanes.
The lawful imprecision of human surface tilt estimation in natural scenes.

The ability to assess how tilted a surface is, or its ‘surface orientation’, is critical for interacting productively with the environment. For example, it helps organisms to determine whether a particular surface is better suited for walking or climbing. Humans and other animals estimate 3-dimensional (3D) surface orientations from 2-dimensional (2D) images on their retinas. But exactly how they calculate the tilt of a surface from the retinal images is not well understood. Scientists have studied how humans estimate surface orientation by showing them smooth (often planar) surfaces with artificial markings. These studies suggested that humans very accurately estimate the direction in which a surface is tilted. But whether humans are as good at estimating surface tilt in the real world, where scenes are more complex than those tested in experiments, is unknown. Now, Kim and Burge show that human tilt estimation in natural scenes is often inaccurate and imprecise. To better understand humans’ successes and failures in estimating tilt, Kim and Burge developed an optimal computational model, grounded in natural scene statistics, that estimates tilt from natural images. Kim and Burge found that the model accurately predicted how humans estimate tilt in natural scenes. This suggests that the imprecise human estimates are not the result of a poorly designed visual system. Rather, humans, like the computational model, make the best possible use of the information images provide to perform an estimation task that is very difficult in natural scenes. The study takes an important step towards generalizing our understanding of human perception from the lab to the real world.
Stereoselective elaboration of the tricyclo[9.3.1.03,8]pentadecane ring system. Atropisomeric control of stereochemistry

Abstract The chemistry of a conformationally locked tricyclo[9.3.1.0 3,8 ]pentadecane skeleton, prepared by an atropselective type 2 intramolecular Diels-Alder reaction, is examined. In many cases, the conformation of the tricycle controls the facial selectivity of the addition of nucleophilic and electrophilic reagents to this ring system.
Olefinic-ester cyclizations using Takai–Utimoto reduced titanium alkylidenes

Abstract The scope and limitations of the Takai–Utimoto reagent to induce the cyclization of olefinic-esters is described. Critical is the steric environment about both the ester and the olefin. Mechanistically, these results support the hypothesis that cyclized product comes from an olefin metathesis, carbonyl-olefination sequence.
Cell-type specific expression of oncogenic and tumor suppressive microRNAs in the human prostate and prostate cancer

MiR-1 and miR-143 are frequently reduced in human prostate cancer (PCa), while miR-141 and miR-21 are frequently elevated. Consequently, these miRNAs have been studied as cell-autonomous tumor suppressors and oncogenes. However, the cell-type specificity of these miRNAs is not well defined in prostate tissue. Through two different microdissection techniques, and droplet digital RT-PCR, we quantified these miRNAs in the stroma and epithelium of radical prostatectomy specimens. In contrast to their purported roles as cell-autonomous tumor suppressors, we found miR-1 and miR-143 expression to be predominantly stromal. Conversely, miR-141 was predominantly epithelial. miR-21 was detected in both stroma and epithelium. Strikingly, the levels of miR-1 and miR-143 were significantly reduced in tumor-associated stroma, but not tumor epithelium. Gene expression analyses in human cell lines, tissues, and prostate-derived stromal cultures support the cell-type selective expression of miR-1, miR-141, and miR-143. Analyses of the PCa Genome Atlas (TCGA-PRAD) showed a strong positive correlation between stromal markers and miR-1 and miR-143, and a strong negative correlation between stromal markers and miR-141. In these tumors, loss of miR-1 and gain of miR-21 was highly associated with biochemical recurrence. These data shed new light on stromal and epithelial miRNA expression in the PCa tumor microenvironment.
Yttrium triflate as an efficient and useful catalyst for chemoselective protection of carbonyl compounds

Carbonyl compounds have been successfully converted into their corresponding oxathiolane, dithiolane, and dithiane derivatives with 2-mercaptoethanol, 1,2-ethanedithiol, and 1,3-propanedithiol using catalytic amount of yttrium triflate. In addition, by using this catalyst, high chemoselective protection of carbonyl compounds has been achieved.
Synthesis and total 1H-NMR assignment of [1]benzothieno-[2,3-c] [1,10]phenanthroline†

The synthesis of [1]benzothieno[2,3-c][1,10]phenanthroline (5) is described. It was obtained in four steps from known starting materials. The basic skeleton of the molecule and of the phenanthroline ring were formed via photocyclization. The total assignment of 1H-nmr spectra was accomplished with the aid of two-dimensional nmr methods.
Seasonal temperature variation influences climate suitability for dengue, chikungunya, and Zika transmission.

Dengue, chikungunya, and Zika virus epidemics transmitted by Aedes aegypti mosquitoes have recently (re)emerged and spread throughout the Americas, Southeast Asia, the Pacific Islands, and elsewhere. Understanding how environmental conditions affect epidemic dynamics is critical for predicting and responding to the geographic and seasonal spread of disease. Specifically, we lack a mechanistic understanding of how seasonal variation in temperature affects epidemic magnitude and duration. Here, we develop a dynamic disease transmission model for dengue virus and Aedes aegypti mosquitoes that integrates mechanistic, empirically parameterized, and independently validated mosquito and virus trait thermal responses under seasonally varying temperatures. We examine the influence of seasonal temperature mean, variation, and temperature at the start of the epidemic on disease dynamics. We find that at both constant and seasonally varying temperatures, warmer temperatures at the start of epidemics promote more rapid epidemics due to faster burnout of the susceptible population. By contrast, intermediate temperatures (24–25°C) at epidemic onset produced the largest epidemics in both constant and seasonally varying temperature regimes. When seasonal temperature variation was low, 25–35°C annual average temperatures produced the largest epidemics, but this range shifted to cooler temperatures as seasonal temperature variation increased (analogous to previous results for diurnal temperature variation). Tropical and sub-tropical cities such as Rio de Janeiro, Fortaleza, and Salvador, Brazil; Cali, Cartagena, and Barranquilla, Colombia; Delhi, India; Guangzhou, China; and Manila, Philippines have mean annual temperatures and seasonal temperature ranges that produced the largest epidemics. However, more temperate cities like Shanghai, China had high epidemic suitability because large seasonal variation offset moderate annual average temperatures. By accounting for seasonal variation in temperature, the model provides a baseline for mechanistically understanding environmental suitability for virus transmission by Aedes aegypti. Overlaying the impact of human activities and socioeconomic factors onto this mechanistic temperature-dependent framework is critical for understanding likelihood and magnitude of outbreaks.
Development and mechanistic study of a new aldehyde decarbonylation catalyst

Rh{sub 2}(PMe{sub 3}){sub 2}(CO){sub 2}Cl{sub 2} (2) catalyzes the decarbonylation of aldehydes. Kinetic studies reveal that the limiting reaction step involves addition of the aldehyde to (2). Rate constants are reported for these reactions including studies of deuterium isotope effects. 22 refs., 4 figs.
Drowned Ancient Islands of the Pacific Basin

Some one hundred and sixty curious flat-topped peaks have been discovered in the Pacific Basin between Hawaii and the Marianas. They appear to be truncated volcanic islands rising about nine to twelve thousand feet from the ocean floor. The flat level summits generally range from three to six thousand feet below sea level. Some less-developed ones are deeper. The flat upper surface is commonly bordered by a gently-sloping shelf a mile or two wide. The summit surfaces are apparently not all of the same age since adjacent peaks may have flat tops which differ in elevation by as much as a thousand feet, though in some cases groups of peaks do have the same elevation. The relationships to atolls of the Marshall Islands group indicate that the surfaces are older than the atoll formation. An hypothesis is tentatively advanced suggesting that the summit surfaces are very old and possibly represent marine planation surfaces in a pre-Cambrian ocean in which reef-building organisms did not exist. It is suggested that the present depths of the surfaces may be accounted for by the relative rise of the ocean surface as a result of accumulation of sediments on the floor. Thus the deeper the surfaces are, the greater their age.
Towards improved testing for deep learning

The growing use of deep neural networks in safety-critical applications makes it necessary to carry out adequate testing to detect and correct any incorrect behavior for corner case inputs before they can be actually used. Deep neural networks lack an explicit control-flow structure, making it impossible to apply to them traditional software testing criteria such as code coverage. In this paper, we examine existing testing methods for deep neural networks, the opportunities for improvement and the need for a fast, scalable, generalizable end-to-end testing method. We also propose a coverage criterion for deep neural networks that tries to capture all possible parts of the deep neural network's logic.
Reduced plasma ascorbic acid levels in recipients of myeloablative conditioning and hematopoietic cell transplantation.

Hematopoietic cell transplantation (HCT) conditioned using myeloablative conditioning (MAC) is complicated by end organ injury due to endothelial dysfunction and graft versus host disease. Mucositis and oxidant injury results in micronutrient deficiency. Ascorbic acid (AA) levels were measured in 15 patients undergoing HCT conditioned with MAC (11 allogeneic and four autologous HCT). Ascorbate levels declined postconditioning to 27.3 μMol/L (±14.1) by day 0 (P = .03 compared with pretransplant baseline), reaching a nadir level of 21.5 (±13.8) on day 14 (P = .003) post-transplant. Patients undergoing allogeneic HCT continued to have low AA levels to day 60 post-transplant. The role of AA in maintaining endothelial function and hematopoietic as well as T-cell recovery is provided, developing the rationale for repletion of vitamin C following HCT.
Hierarchical Clustering with Structural Constraints.

Hierarchical clustering is a popular unsupervised data analysis method. For many real-world applications, we would like to exploit prior information about the data that imposes constraints on the clustering hierarchy, and is not captured by the set of features available to the algorithm. This gives rise to the problem of "hierarchical clustering with structural constraints". Structural constraints pose major challenges for bottom-up approaches like average/single linkage and even though they can be naturally incorporated into top-down divisive algorithms, no formal guarantees exist on the quality of their output. In this paper, we provide provable approximation guarantees for two simple top-down algorithms, using a recently introduced optimization viewpoint of hierarchical clustering with pairwise similarity information [Dasgupta, 2016]. We show how to find good solutions even in the presence of conflicting prior information, by formulating a constraint-based regularization of the objective. We further explore a variation of this objective for dissimilarity information [Cohen-Addad et al., 2018] and improve upon current techniques. Finally, we demonstrate our approach on a real dataset for the taxonomy application.
The weak Lefschetz property for monomial ideals of small type

Abstract In this work a combinatorial approach towards the weak Lefschetz property is developed that relates this property to enumerations of signed perfect matchings as well as to enumerations of signed families of non-intersecting lattice paths in certain triangular regions. This connection is used to study Artinian quotients by monomial ideals of a three-dimensional polynomial ring. Extending a main result in the recent memoir [1] , we completely classify the quotients of type two that have the weak Lefschetz property in characteristic zero. We also derive results in positive characteristic for quotients whose type is at most two.
Nonlocal Robin Laplacians and some remarks on a paper by Filonov on eigenvalue inequalities

Abstract The aim of this paper is twofold: First, we characterize an essentially optimal class of boundary operators Θ which give rise to self-adjoint Laplacians − Δ Θ , Ω in L 2 ( Ω ; d n x ) with (nonlocal and local) Robin-type boundary conditions on bounded Lipschitz domains Ω ⊂ R n , n ∈ N , n ⩾ 2 . Second, we extend Friedlander's inequalities between Neumann and Dirichlet Laplacian eigenvalues to those between nonlocal Robin and Dirichlet Laplacian eigenvalues associated with bounded Lipschitz domains Ω, following an approach introduced by Filonov for this type of problems.
Emergence of addictive behaviors in reinforcement learning agents

This paper presents a novel approach to the technical analysis of wireheading in intelligent agents. Inspired by the natural analogues of wireheading and their prevalent manifestations, we propose the modeling of such phenomenon in Reinforcement Learning (RL) agents as psychological disorders. In a preliminary step towards evaluating this proposal, we study the feasibility and dynamics of emergent addictive policies in Q-learning agents in the tractable environment of the game of Snake. We consider a slightly modified settings for this game, in which the environment provides a "drug" seed alongside the original "healthy" seed for the consumption of the snake. We adopt and extend an RL-based model of natural addiction to Q-learning agents in this settings, and derive sufficient parametric conditions for the emergence of addictive behaviors in such agents. Furthermore, we evaluate our theoretical analysis with three sets of simulation-based experiments. The results demonstrate the feasibility of addictive wireheading in RL agents, and provide promising venues of further research on the psychopathological modeling of complex AI safety problems.
A simple proof of threshold saturation for coupled scalar recursions

Low-density parity-check (LDPC) convolutional codes (or spatially-coupled codes) have been shown to approach capacity on the binary erasure channel (BEC) and binary-input memoryless symmetric channels. The mechanism behind this spectacular performance is the threshold saturation phenomenon, which is characterized by the belief-propagation threshold of the spatially-coupled ensemble increasing to an intrinsic noise threshold defined by the uncoupled system. In this paper, we present a simple proof of threshold saturation that applies to a broad class of coupled scalar recursions. The conditions of the theorem are verified for the density-evolution (DE) equations of irregular LDPC codes on the BEC, a class of generalized LDPC codes, and the joint iterative decoding of LDPC codes on intersymbol-interference channels with erasure noise. Our approach is based on potential functions and was motivated mainly by the ideas of Takeuchi et al. The resulting proof is surprisingly simple when compared to previous methods.
Positive semigroups and algebraic Riccati equations in Banach spaces

We generalize Wonham’s theorem on solvability of algebraic operator Riccati equations to Banach spaces, namely there is a unique stabilizing solution to $$A^*P+PA-PBB^*P+C^*C=0$$ when (A, B) is exponentially stabilizable and (C, A) is exponentially detectable. The proof is based on a new approach that treats the linear part of the equation as the generator of a positive semigroup on the space of symmetric operators from a Banach space to its dual, and the quadratic part as an order concave map. A direct analog of global Newton’s iteration for concave functions is then used to approximate the solution, the approximations converge in the strong operator topology, and the convergence is monotone. The linearized equations are the well-known Lyapunov equations of the form $$A^*P+PA=-Q$$ , and semigroup stability criterion in terms of them is also generalized.
Image-Dependent Local Entropy Models for Learned Image Compression

The leading approach for image compression with artificial neural networks (ANNs) is to learn a nonlinear transform and a fixed entropy model that are optimized for rate-distortion performance. We show that this approach can be significantly improved by incorporating spatially local, image-dependent entropy models. The key insight is that existing ANN-based methods learn an entropy model that is shared between the encoder and decoder, but they do not transmit any side information that would allow the model to adapt to the structure of a specific image. We present a method for augmenting ANN-based image coders with image-dependent side information that leads to a 17.8% rate reduction over a state-of-the-art ANN-based baseline model on a standard evaluation set, and 70-98% reductions on images with low visual complexity that are poorly captured by a fixed, global entropy model.
Local water storage control for the developing world

Most cities in India do not have water distribution networks that provide water throughout the entire day. As a result, it is common for homes and apartment buildings to utilize water storage systems that are filled during a small window of time in the day when the water distribution network is active. However, these water storage systems do not have disinfection capabilities, and so long durations of storage (i.e., as few as four days) of the same water leads to substantial increases in the amount of bacteria and viruses in that water. This paper considers the stochastic control problem of deciding how much water to store each day in the system, as well as deciding when to completely empty the water system, in order to tradeoff: the financial costs of the water, the health costs implicit in long durations of storing the same water, the potential for a shortfall in the quantity of stored versus demanded water, and water wastage from emptying the system. To solve this problem, we develop a new Binary Dynamic Search (BiDS) algorithm that is able to use binary search in one dimension to compute the value function of stochastic optimal control problems with controlled resets to a single state and with constraints on the maximum time span in between resets of the system.
Differentiable Antithetic Sampling for Variance Reduction in Stochastic Variational Inference

Stochastic optimization techniques are standard in variational inference algorithms. These methods estimate gradients by approximating expectations with independent Monte Carlo samples. In this paper, we explore a technique that uses correlated, but more representative, samples to reduce estimator variance. Specifically, we show how to generate antithetic samples that match sample moments with the true moments of an underlying importance distribution. Combining a differentiable antithetic sampler with modern stochastic variational inference, we showcase the effectiveness of this approach for learning a deep generative model. An implementation is available at https://github.com/mhw32/antithetic-vae-public.
ADDING INVERSES TO DIAGRAMS II: INVERTIBLE HOMOTOPY THEORIES ARE SPACES

In previous work, we showed that there are appropriate model category structures on the category of simplicial categories and on the category of Segal precategories, and that they are Quillen equivalent to one another and to Rezk’s complete Segal space model structure on the category of simplicial spaces. Here, we show that these results still hold if we instead use groupoid or \invertible" cases. Namely, we show that model structures on the categories of simplicial groupoids, Segal pregroupoids, and invertible simplicial spaces are all Quillen equivalent to one another and to the standard model structure on the category of spaces. We prove this result using two difierent approaches to invertible complete Segal spaces and Segal groupoids.
6thSense: A Context-aware Sensor-based Attack Detector for Smart Devices

Sensors (e.g., light, gyroscope, accelerotmeter) and sensing enabled applications on a smart device make the applications more user-friendly and efficient. However, the current permission-based sensor management systems of smart devices only focus on certain sensors and any App can get access to other sensors by just accessing the generic sensor API. In this way, attackers can exploit these sensors in numerous ways: they can extract or leak users' sensitive information, transfer malware, or record or steal sensitive information from other nearby devices. In this paper, we propose 6thSense, a context-aware intrusion detection system which enhances the security of smart devices by observing changes in sensor data for different tasks of users and creating a contextual model to distinguish benign and malicious behavior of sensors. 6thSense utilizes three different Machine Learning-based detection mechanisms (i.e., Markov Chain, Naive Bayes, and LMT) to detect malicious behavior associated with sensors. We implemented 6thSense on a sensor-rich Android smart device (i.e., smartphone) and collected data from typical daily activities of 50 real users. Furthermore, we evaluated the performance of 6thSense against three sensor-based threats: (1) a malicious App that can be triggered via a sensor (e.g., light), (2) a malicious App that can leak information via a sensor, and (3) a malicious App that can steal data using sensors. Our extensive evaluations show that the 6thSense framework is an effective and practical approach to defeat growing sensor-based threats with an accuracy above 96% without compromising the normal functionality of the device. Moreover, our framework costs minimal overhead.
The Manifold of Human Emotions

Sentiment analysis predicts the presence of positive or negative emotions in a text document. In this paper, we consider higher dimensional extensions of the sentiment concept, which represent a richer set of human emotions. Our approach goes beyond previous work in that our model contains a continuous manifold rather than a finite set of human emotions. We investigate the resulting model, compare it to psychological observations, and explore its predictive capabilities.
Gradient Descent for Spiking Neural Networks

Most large-scale network models use neurons with static nonlinearities that produce analog output, despite the fact that information processing in the brain is predominantly carried out by dynamic neurons that produce discrete pulses called spikes. Research in spike-based computation has been impeded by the lack of efficient supervised learning algorithm for spiking neural networks. Here, we present a gradient descent method for optimizing spiking network models by introducing a differentiable formulation of spiking dynamics and deriving the exact gradient calculation. For demonstration, we trained recurrent spiking networks on two dynamic tasks: one that requires optimizing fast (~ millisecond) spike-based interactions for efficient encoding of information, and a delayed-memory task over extended duration (~ second). The results show that the gradient descent approach indeed optimizes networks dynamics on the time scale of individual spikes as well as on behavioral time scales. In conclusion, our method yields a general purpose supervised learning algorithm for spiking neural networks, which can facilitate further investigations on spike-based computations.
Knowledge in Communication Networks

The paper investigates epistemic properties of information flow under communication protocols with a given topological structure of the communication network. The main result is a sound and complete logical system that describes all such properties. The system consists of a variation of the multi-agent epistemic logic S5 extended by a new network-specific Gateway axiom.
D2D data offloading in vehicular environments with optimal delivery time selection

Abstract Within the framework of a Device-to-Device (D2D) data offloading system for cellular networks, we propose a Content Delivery Management System (CDMS) in which the instant for transmitting a content to a requesting node, through a D2D communication, is selected to minimize the energy consumption required for the transmission. The proposed system is particularly fit to highly dynamic scenarios, such as vehicular ones, where the network topology changes at a rate which is comparable with the order of magnitude of the delay tolerance. We present an analytical framework able to predict the system performance, in terms of energy consumption, considering concurrent requests for contents with different popularity. We validate the analytical model through simulations, and provide a thorough performance evaluation of the proposed CDMS, in terms of energy consumption and spectrum use. The proposed CDMS can be configured in two ways: (i) either use I2D transmissions only as a last resort, if it is not possible to serve request through D2D offloading within the limit of the delay tolerance; or (ii) include the possibility for the Base Stations (BSs) to transmit contents even before the deadline, if this is found to be more energy efficient from the point of view of the overall energy consumption, renouncing a portion of the offloading opportunities. The proposed scheme is benchmarked against a plain classic cellular scheme, a cellular (I2D only) scheme with optimal Infrastructure-to-Device (I2D) transmission scheduling for delay-tolerant applications, and a D2D data offloading scheme (proposed in previous works) in which the D2D transmission is performed as soon as a close-by device with the required content is found (i.e., without optimizing the transmission instant). We implemented a quite detailed simulator complete of Radio Resource Management (RRM) over the MAC layer of a multi carrier system, in a multi-cell scenario. Our results show that the proposed CDMS can induce a reduction of an order of magnitude, i.e. 90% or higher, of the energy consumed by the devices to implement D2D offloading, with respect to the benchmark D2D offloading scheme. At the same time, we observed a reduction of the energy consumption of the overall system in the order of 30%, under conservative assumptions. Finally, the system induces a remarkable degree of spatial frequency reuse, thus reducing the overall spectrum occupation.
A Sharp analog of Young's Inequality on $S^N$ and Related Entropy Inequalities

We prove a sharp analog of Young’s inequality on SN, and deduce from it certain sharp entropy inequalities. The proof turns on constructing a nonlinear heat flow that drives trial functions to optimizers in a monotonic manner. This strategy also works for the generalization of Young’s inequality on RN to more than three functions, and leads to significant new information about the optimizers and the constants.