cssi/SciSciGPT-SciSciNet huggingface dataset:
A direct-conversion receiver IC for WCDMA mobile systems

A prototype design of a 2.7-3.3-V 14.5-mA SiGe direct-conversion receiver IC for use in third-generation wide-band code-division multiple-access (3G WCDMA) mobile cellular systems has been completed and measured. The design includes a bypassable low-noise amplifier (LNA), a quadrature downconverter, a local-oscillator frequency divider and quadrature generator, and variable-gain baseband amplifiers integrated on chip. The design achieves a cascaded, LNA-referred noise figure (including an interstage surface acoustic wave filter) of 4.0 dB, an in-band IIP3 of -18.6 dBm, and local-oscillator leakage at the LNA input of -112 dBm. The static sensitivity performance of the receiver IC is characterized using a software baseband processor to compute link bit-error rate.
Measurement of Quadratic Terahertz Optical Nonlinearities Using Second-Harmonic Lock-in Detection

We demonstrate a method to measure quadratic terahertz optical nonlinearities in terahertz time-domain spectroscopy by measuring the quadratic terahertz Kerr effect in a (110) GaP crystal in the presence of strong linear electro-optic Pockels effect [1]. © 2019 The Author(s)
Does the Supreme Court really not apply Chevron when it should

Abstract William Eskridge and Lauren Baer’s (96 G eo . L.J. 1083 (2008)) “empirical study of all 1014 Supreme Court cases between Chevron and Hamdan in which an agency interpretation of a statute was at issue” finds that “the Court does not apply the Chevron framework in nearly three-quarters of the cases where it would appear applicable.” Our reexamination of this study finds that the fraction of such cases is far lower, and indeed closer to zero. Our main methodological innovation is to infer Chevron applicability from Supreme Court litigants’ briefs rather than our own evaluation of the cases’ facts, as in Eskridge and Baer’s study. In over half the cases flagged by Eskridge and Baer, neither of the parties (nor, where applicable, the Solicitor General as amicus) cited Chevron, and in almost half of the cases within that subset, no one argued for or against deference of any kind. In most of a sample of the remaining cases, the Supreme Court either did not need to reach the Chevron issue, or actually applied it, at least in an abbreviated form.
Multi-Stream Beam-Training for mmWave MIMO Networks

Multi-stream 60 GHz communication has the potential to achieve data rates up to $100$ Gbps via multiplexing multiple data streams. Unfortunately, establishing multi-stream directional links can be a high overhead procedure as the search space increases with the number of spatial streams and the product of AP-client beam resolution. In this paper, we present MUlti-stream beam-Training for mm-wavE networks (MUTE) a novel system that leverages channel sparsity, GHz-scale sampling rate, and the knowledge of mm-Wave RF codebook beam patterns to construct a set of candidate beams for multi-stream beam steering. In 60 GHz WLANs, the AP establishes and maintains a directional link with every client through periodic beam training. MUTE repurposes these beam acquisition sweeps to estimate the Power Delay Profile (PDP) of each beam with zero additional overhead. Coupling PDP estimates with beam pattern knowledge, MUTE selects a set of candidate beams that capture diverse or ideally orthogonal paths to obtain maximum stream separability. Our experiments demonstrate that MUTE achieves 90% of the maximum achievable aggregate rate while incurring only 0.04% of exhaustive search's training overhead.
Is overconfidence a social liability?: The effect of verbal versus nonverbal expressions of confidence

[Correction Notice: An Erratum for this article was reported in Vol 116(3) of Journal of Personality and Social Psychology (see record 2019-08943-002). In the article "Is Overconfidence a Social Liability? The Effect of Verbal Versus Nonverbal Expressions of Confidence" by Elizabeth R. Tenney, Nathan L. Meikle, David Hunsaker, Don A. Moore, and Cameron Anderson (Journal of Personality and Social Psychology. Advance online publication. October 11, 2018. http://dx.doi.org/10.1037/pspi0000150), the Editor' Note acknowledging David Dunning as the action editor for this article was omitted. All versions of this article have been corrected.] What are the reputational consequences of being overconfident? We propose that the channel of confidence expression is one key moderator-that is, whether confidence is expressed verbally or nonverbally. In a series of experiments, participants assessed target individuals (potential collaborators or advisors) who were either overconfident or cautious. Targets expressed confidence, or a lack thereof, verbally or nonverbally. Participants then learned targets' actual performance. Across studies, overconfidence was advantageous initially-regardless of whether targets expressed confidence verbally or nonverbally. After performance was revealed, overconfident targets who had expressed confidence verbally were viewed more negatively than cautious targets; however, overconfident targets who had expressed confidence nonverbally were still viewed more positively than cautious ones. The one condition wherein nonverbal overconfidence was detrimental was when confidence was clearly tied to a falsifiable claim. Results suggest that, compared with verbal statements, nonverbal overconfidence reaps reputational benefits because of its plausible deniability. (PsycINFO Database Record (c) 2019 APA, all rights reserved).
3D Localization for Sub-Centimeter Sized Devices

The vision of tracking small IoT devices runs into the reality of localization technologies --- today it is difficult to continuously track objects through walls in homes and warehouses on a coin cell battery. While Wi-Fi and ultra-wideband radios can provide tracking through walls, they do not last more than a month on small coin and button cell batteries since they consume tens of milliwatts of power. We present the first localization system that consumes microwatts of power at a mobile device and can be localized across multiple rooms in settings like homes and hospitals. To this end, we introduce a multi-band backscatter prototype that operates across 900 MHz, 2.4 and 5 GHz and can extract the backscatter phase information from signals that are below the noise floor. We build sub-centimeter sized prototypes which consume 93 μW and could last five to ten years on button cell batteries. We achieved ranges of up to 60 m away from the AP and accuracies of 2, 12, 50 and 145 cm at 1, 5, 30 and 60 m respectively. To demonstrate the potential of our design, we deploy it in two real-world scenarios: five homes in a metropolitan area and the surgery wing of a hospital in patient pre-op and post-op rooms as well as storage facilities.
Trace abstraction modulo probability

We propose trace abstraction modulo probability, a proof technique for verifying high-probability accuracy guarantees of probabilistic programs. Our proofs overapproximate the set of program traces using failure automata, finite-state automata that upper bound the probability of failing to satisfy a target specification. We automate proof construction by reducing probabilistic reasoning to logical reasoning: we use program synthesis methods to select axioms for sampling instructions, and then apply Craig interpolation to prove that traces fail the target specification with only a small probability. Our method handles programs with unknown inputs, parameterized distributions, infinite state spaces, and parameterized specifications. We evaluate our technique on a range of randomized algorithms drawn from the differential privacy literature and beyond. To our knowledge, our approach is the first to automatically establish accuracy properties of these algorithms.
Privacy-Preserving Aggregation of Controllable Loads to Compensate Fluctuations in Solar Power

Cybersecurity and privacy are of the utmost importance for safe, reliable operation of the electric grid. It is well known that the increased connectivity/interoperability between all stakeholders (e.g., utilities, suppliers, and consumers) will enable personal information collection. Significant advanced metering infrastructure (AMI) deployment and demand response (DR) programs across the country, while enable enhanced automation, also generate energy data on individual consumers that can potentially be used for exploiting privacy. Inspired by existing works which consider DR, battery-based perturbation, and differential privacy noise adding, we novelly consider the aggregator (cluster) level privacy issue in the DR framework of solar photovoltaic (PV) generation following. Different from most of the existing works which mainly rely on the charging/discharging scheduling of rechargeable batteries, we utilize controllable building loads to serve as virtual storage devices to absorb a large portion of the PV genertaion while delicately keeping desired noisy terms to satisfy the differential privacy for the raw load profiles at the aggregator level. This not only ensures differential privacy, but also improves the DR efficiency in load following since part of the noisy signal in solar PV generation has been filtered out. In particular, a mixed integer quadratic optimization problem is formulated to optimally dispatch a population of on/off controllable loads to achieve this privacy-preserving DR service.
Uphill Diffusion of Antioxidant in Cross-Linked Polyethylene

Cross-linked polyethylene (XLPE or PEX) is a major material for cable insulation. Antioxidants are usually added to XLPE to prevent the insulation from oxidation. However, antioxidants diffuse out of an XLPE matrix during thermal ageing, which accelerates oxidation, causing the degradation of the insulation. Few models have been developed to represent the diffusion behavior of the antioxidant. One paper has reported that the antioxidant in XLPE migrates from low to high concentration but no explanation has been given. Starting with the theories of uphill diffusion and reaction-diffusion, this paper has developed a physics-based model explicating why the antioxidant migrates against the concentration gradient. In addition to the concentration, the activity coefficient (y) of the antioxidant is considered. With physical significance, this study mathematically proves the inhomogeneous distribution of the diffusing oxygen in XLPE makes y a function of oxygen concentration. y determines the driving force rendering the uphill diffusion of the antioxidant. Besides the y function, the decomposition rate of the antioxidant has been modeled. Experimental data are used to validate the proposed model.
100% Reliable Frequency-Resolved Optical Gating Pulse-Retrieval Algorithmic Approach

We introduce a FROG algorithmic approach that always converges and is faster. It involves retrieving the correct spectrum directly from the trace and implementing a multi-grid scheme with multiple initial guesses
Increasing the power of specification tests

Abstract This paper shows how to increase the power of Hausman’s (1978) specification test as well as the difference test in a large class of models. The idea is to impose the restrictions of the null and the alternative hypotheses when estimating the covariance matrix. If the null hypothesis is true then the proposed test has the same distribution as the existing ones in large samples. If the hypothesis is false then the proposed test statistic is larger with probability approaching one as the sample size increases in several important applications, including testing for endogeneity in the linear model.
Who's minding the kids? Experimental evidence on the demand for child care quality

Abstract Despite the well-documented benefits of high-quality child care, many preschool-age children in the U.S. attend low-quality programs. Accordingly, improving the quality of child care is increasingly an explicit goal of government policy. However, accomplishing this goal requires a thorough understanding of the factors that influence parents’ child care decisions. This paper provides the first evidence on the demand for child care characteristics in the market for home-based care. Using a randomized audit design, we study three dimensions of caregiving: affordability (i.e., the hourly price of child care), quality (i.e., caregiver education and experience), and convenience (i.e., caregiver car ownership and availability). We find that while parents are extremely sensitive to the cost of child care, they also have strong preferences for quality, particularly caregivers’ educational attainment. Furthermore, we obtain mixed results on the convenience dimensions of child care, with parents valuing those owning a car but not those with more availability. Finally, we find significant heterogeneity in child care preferences according to families’ age of youngest child, race and ethnicity, and willingness-to-pay. Our findings are consistent with the notion that the problem of low-quality in the U.S. child care market may be explained by lack of affordability or the informational resources to identify high-quality care, rather than an undervaluation of such care by parents.
Predictive utility of an adapted Marshall head CT classification scheme after traumatic brain injury

Objective: To study the predictive relationship among persons with traumatic brain injury (TBI) between an objective indicator of injury severity (the adapted Marshall computed tomography [CT] clas...
Divisibility Properties of Coefficients of Level $p$ Modular Functions for Genus Zero Primes

Lehner's 1949 results on the $j$-invariant showed high divisibility of the function's coefficients by the primes $p\in\{2,3,5,7\}$. Expanding his results, we examine a canonical basis for the space of level $p$ modular functions holomorphic at the cusp 0. We show that the Fourier coefficients of these functions are often highly divisible by these same primes.
The combined effects of salivas and occlusal indicators on occlusal contact forces.

BACKGROUND Some occlusal detection products are designed for use on dry teeth, but this is not always achieved. Others are suited for dry and wet applications. OBJECTIVE The objective of this study is to assess the combined effects, on occlusal contact forces, of two previously studied affecting variables-occlusal detection products and saliva. METHODS We used a full-arch dentiform with three occlusal detection products (an articulating film, an articulation paper and T-Scan) in combination with human (HS) and an artificial saliva. The maxillary arch assembly, weighing ~54 N (the maximum bite force), was lowered onto (occlusion) and lifted off (disclusion) of the mandibular arch through 10 cycles by a mechanical testing machine. The forces and moments acting on the mandibular arch were continuously recorded by a load cell that supported it. RESULTS The maximum values of Flateral (the in-occlusal plane component of the occlusal contact force) were analysed by occlusion/disclusion separately using one-way ANOVA, with factor for group type to identify the significant effect of salivas on products, effect of products, effect of salivas with products, effect of human saliva. A difference in occlusion and/or in disclusion was considered different. Statistical differences (P < 0.0001) in Flateral were found in: dry product vs product + HS, dry product vs product + artificial saliva (with articulating film and T-Scan) and HS vs product + HS (with articulation paper and T-Scan). CONCLUSION All products were affected by the salivas, except articulation paper by artificial saliva.
Fast-charging station deployment for battery electric bus systems considering electricity demand charges

Abstract Battery electric buses (BEBs) are considered a promising alternative for bus fleets to alleviate the growing environmental problems in urban areas, and fast-charging technology has been introduced to BEB systems to help electric buses provide uninterrupted service without the need to carry a large onboard battery. The general consensus is that fast-charging may lead to high electricity demand charges, thus compromising the competitiveness of electric bus systems. However, a majority of current electric bus fast-charging station deployment models ignore these charges. The present study addresses this gap by explicitly considering the electricity demand charges in the optimal deployment problem of fast-charging stations for battery electric bus systems. The problem is formulated as a mixed integer linear programming model with the objective of minimizing the total cost of vehicle batteries, fast-charging stations, energy storage systems, and electricity demand charges. Numerical studies based on a real-world bus network in Salt Lake City, Utah, are conducted to demonstrate the effectiveness of the proposed model. The results show that the proposed model can effectively determine the deployment of fast-charging stations, the design of vehicle battery sizes, as well as the installation of energy storage systems. This study demonstrates that energy storage systems are a potential remedy for high demand charges from fast-charging.
DistriPlan: an optimized join execution framework for geo-distributed scientific data

Scientific data is frequently stored across geographically distributed data repositories. Although there have been recent efforts to query scientific datasets using structured query operators, they have not yet supported joins across distributed data repositories. This paper describes a framework that supports join-like operations over multi-dimensional array datasets that are spread across multiple sites. More specifically, we first formally define join operations over array datasets and establish how they arise in the context of scientific data analysis. We then describe a methodology for optimizing such operations—components of our approach include enumeration algorithms for candidate plans, methods for pruning plans before they are enumerated, and a detailed cost model for selecting the best (cheapest) plan. We evaluate our approach using candidate queries, and show that the optimization effort is practical and profitable—query performance was improved significantly using our approach.
Generalized Integrated Brownian Fields for Simulation Metamodeling

In operations research, stochastic simulations are often used to model complex systems. Simulation runs can be time-consuming to execute, especially when there are many scenarios that need to be ev...
Synthetic routes toward 2-substituted 2-imidazolines

Methods for the synthesis of 2-substituted 2-imidazolines are reviewed. While older, more established methods continue to be used for the preparation of these compounds, more recent reports describe techniques that provide multiple points of diversity, making them especially useful in library development for this pharmacologically-important class of compounds. <div class=" textboxdefault "> Figure options Download full-size image Download as PowerPoint slide
Structural behavior of Sr2Bi2O5 at high pressures

Abstract The structure of Bi 2 Sr 2 O 5 at high pressures is investigated by in situ X-ray diffraction (XRD) and Raman scattering methods. Raman results indicate that there are two pressure-induced phase transitions that occurred at ∼1.4 and ∼11 GPa, respectively. XRD measurements reveal only one high-pressure phase, which is indexed with a monoclinic unit cell and the possible space groups are P 121(No. 3), P 1 m 1(No. 6) and P 12 /m 1(No. 10). The phase transition above 11 GPa is probably due to the symmetry change without discontinuity of the unit cell. The high-pressure phase is quenchable and it is a new dense form and about 11% denser than the normal orthorhombic Bi 2 Sr 2 O 5 at room conditions.
The Synthesis of Heterocycles Using Cascade Chemistry

Publisher Summary This chapter reviews the kind of reactions that have been sequenced into cascades to produce heterocyclic molecules. The fact that multiple reactions give rise to a cascade sequence makes the categorization of these processes difficult. From the selective sampling of cascade reactions for the synthesis of heterocyclic molecules that has been outlined in this chapter, it is clear that virtually any reaction can be incorporated into a tandem sequence. Many of these cascades rapidly construct hetero-polycyclic systems that are difficult to produce in other ways. Several cascade sequences for heterocyclic synthesis have been well explored: (1) Padwa's rhodium carbene-initiated dipolar cycloadditions, (2) Denmark's nitroalkene [4+2]/[3+2]-cycloadditions, (3) Overman's Aza-Cope/Mannich cascade, (4) Bunce's conjugate addition strategy, (5) Molina's Aza-Wittig/heterocumulene cyclization reactions, and (6) Grigg's use of relays and switches in palladium-mediated cascades have matured into significant synthetic tools. Familiar multi-component reactions, such as the Ugi reaction, are being used in interesting ways. Other sequences show tremendous promise. Fu's asymmetric Kinugasa reaction, indium-initiated radical cascades, Buchwald's copper catalyzed N-arylation reactions, Trost's alkyne heterocyclization, and Hoveyda and Schrock tandem AROM/RCM reactions all provide improvements in stereoselectivity and involve the use of environmentally benign reagents. Continued development of these cascade reactions will have a significant impact on the processes used to make heterocyclic compounds on an industrial scale.
Some Recent Developments in the Application of Nuclear Magnetic Resonance to Magnetically Ordered Systems

A brief outline of experimental results of NMR studies of ternary systems Fe3−xTxSi are presented. The observation of transition metal site selectivity, which correlates with electronegativity and atomic size, enables one to develop a quantitative model relating specific B sites and their corresponding near-neighbor moments. Brief reference is made to recent work on amorphous metals, short-range ordering, and the initial NMR studies of multilayer systems.
Synthesis of Thermally Stable Silica-Pillared Layered Manganese Oxide by an Intercalation/Solvothermal Reaction

Silica-pillared layered manganese oxide with high surface area and high thermal stability was first synthesized from birnessite(H)-type manganese oxide by intercalation of octylamine followed by tetraethyl orthosilicate (TEOS) molecules and then by solvothermal treatment in TEOS liquid. Layered phases of manganese oxide with basal spacings of 2.01 and 2.43 nm, respectively, were obtained for each intercalation reaction. The Si/Mn molar ratio increased from 0.63 to 0.84 by the solvothermal treatment, but the basal spacing (2.44 nm) of the layer barely increased. The increase of silica content stabilized the pillared structure against thermal treatment. Porous layered manganese oxides were obtained by heating the silica-pillared material at appropriate temperatures. The manganese oxide sample obtained at 400 °C had a BET surface area of 260 m2/g with a gallery height of about 1.6 nm between layers.
Asymmetric Synthesis of Sesaminone: Confirmation of Its Structure and Determination of Its Absolute Configuration.

An asymmetric synthesis of the naturally occurring antipode of the tetrahydrofuran lignan sesaminone ((−)-1) has been achieved. An X-ray crystal structure of the synthetic material validated the structure proposed in the literature for this lignan. Additionally, the absolute configuration of the natural product was established by correlation of the synthetic tetrahydrofuran with the known absolute configuration of l-Phe. The opening of the synthesis was a diastereoselective Evans aldol reaction between N-4-pentenoyloxazolidinone 6 and piperonal. Reduction of the major diastereomer of the aldol product provided enantiomerically pure diol 4. The primary and secondary hydroxyl groups of 4 were protected in tandem to generate silyl ether-MOM ether 9. The vinyl group contained in 9 was then elaborated, via a series of four steps, to aryl ketone 10. This aryl ketone was transformed to a mixture of silyl enol ether stereoisomers (11a,b); TiCl4-mediated activation of the MOM ethers contained in this mixture of en...
Radical and polar reactivity of radical ions in solution. A new look at an old problem

It is proposed that both polar and radical reactions should be considered when discussing radical ion reactivity. The fact that only the polar reactivity has dominated previous discussions is pointed out. It is argued that if the configuration mixing model is applicable for the estimation of radical cation-nucleophile (or cation-nucleophile) combination reaction barriers, the theory should also explain the reactivity of the proton toward anionic nucleophiles. The model severely overestimates reaction barriers for the latter reactions. The discussion is centered around the following hypothesis: In the absence of severe steric effects, the reactivity of radical ions, especially evident in the reactions with radicals (for example very few radical cations react with dioxygen at measurable rates), is dominated by the degree of coupling between charge and radical centers. Evidence from the literature supporting the hypothesis is presented for a number of different classes of radical ion reactions. Further work to test the validity of the hypothesis is proposed for many of the reaction types. Triarylmethyl radicals and carbenium ions are suggested as models to which the radical and polar reactivities of 9,10-diarylanthracene radical cations may be compared. It is concluded that the radical cation/carbenium ion comparison (for the reaction with acetate ion) would show similar reactivities while the radical cation/free radical comparison (for the reaction with dioxygen) would fail, since no reaction at all would be observed with the radical cation while the free radical reacts rapidly.
Hydrodefluorination of Fluorobenzene and 1,2-Difluorobenzene under Mild Conditions over Rhodium Pyridylphosphine and Bipyridyl Complexes Tethered on a Silica-Supported Palladium Catalyst

Fluorobenzene and 1,2-difluorobenzene are defluorinated under very mild conditions by H2 (4 atm) at 70 °C in the presence of NaOAc. The heterogeneous catalysts for these reactions contain the rhodi...
Preparation of FeAPO-5 Molecular Sieve Thin Films and Application as a Capacitive Type Humidity Sensor

Thin films of FeAPO-5 molecular sieves deposited on TiN-coated silicon wafers have been generated using pulsed laser ablation. The FeAPO-5 films were employed as the dielectric phase in a capacitiv...
Synthesis, structure, and spectroscopic characterization of three uranyl phosphates with unique structural units

Single crystals of Zn{sub 4}(OH){sub 2}[(UO{sub 2})(PO{sub 4}){sub 2}(OH){sub 2}(H{sub 2}O)] (UZnP), Cs[(UO{sub 2})(HPO{sub 4})NO{sub 3}] (UCsP), and In{sub 3}[(UO{sub 2}){sub 2}(PO{sub 4}){sub 4}OH(H{sub 2}O){sub 6}].2H{sub 2}O (UInP) were obtained from hydrothermal reactions and have been structurally and chemically characterized. UZnP crystallizes in space group Pbcn, a=8.8817(7), b=6.6109(5), c=19.569(1) A; UCsP crystallizes in P-1, a=7.015(2), b=7.441(1), c=9.393(2) A, {alpha}=72.974(2), {beta}=74.261(2), {gamma}=79.498(2); and UInP crystallizes in P-1, a=7.9856(5), b=9.159(1), c=9.2398(6) A {alpha}=101.289(1), {beta}=114.642(1), {gamma}=99.203(2). The U{sup 6+} cations are present as (UO{sub 2}){sup 2+} uranyl ions coordinated by five O atoms to give pentagonal bipyramids. The structural unit in UZnP is a finite cluster containing a uranyl pentagonal bipyramid that shares corners with two phosphate tetrahedra. The structural unit in UCsP is composed of uranyl pentagonal bipyramids with one chelating nitrate group that are linked into chains by three bridging hydrogen phosphate tetrahedra. In UInP, the structural unit contains pairs of edge-sharing uranyl pentagonal bipyramids with two chelating phosphate tetrahedra that are linked into chains through two bridging phosphate tetrahedra. Indium octahedra link these uranyl phosphate chains into a 3-dimensional framework. All three compounds exhibit unique structural units that deviate from the typical layered structures observed in uranyl phosphate solid-state chemistry.more » - Graphical abstract: Three new uranyl phosphates with unique structural units are reported. Black-Small-Square Highlights: Black-Right-Pointing-Pointer Three new uranyl phosphates have been synthesized hydrothermally. Black-Right-Pointing-Pointer Single crystal analyses reveal unique structural units. Black-Right-Pointing-Pointer The dimensionality of these compounds deviate from typical U{sup 6+} layered structures.« less
Molecular Gymnastics of Alkynes Orchestrated by Ruthenium Complexes

Ruthenium complexes catalyze a variety of addition or isomerization reactions that are highly atom economical. Terminal alkynes react with allyl alcohols to form β,γ-unsaturated ketones that can be readily isomerized to α,β-unsaturated ketones via transient vinylidene complexes. A cyclization via a transient allenylidene complex concomitant with this addition represents a novel way to build heterocycles. Ancillary studies with these catalysts revealed an internal oxidation reduction whereby allyl alcohols are isomerized to saturated ketones and propargyl alcohols are isomerized to α,β-unsaturated carbonyl compounds. Consideration of the reaction mechanism led to a general Alder ene type reaction wherein alkynes serve as the enophile and alkenes serve as the ene component. These discoveries have led to a number of efficient total syntheses of biologically interesting targets. Mechanistic investigations into the activation of a ruthenium complex led to the discovery of a novel bis-homo-Diels-Alder reaction of 1,4-cyclooctadiene.
Reactivity and rearrangements of dialkyl- and diarylvinylsulfonium salts with indole-2- and pyrrole-2-carboxaldehydes

Abstract Various dialkyl- and diarylvinylsulfonium salts react with indole-2-carboxaldehydes in the presence of sodium hydride and sodium azide to form tricyclic azido alcohols analogous to 2 . With pyrrole-2-carboxaldehyde, [2,3] sigmatropic and other rearrangements occur except in the case of diphenylvinylsulfonium trifluoromethanesulfonate where the annulation reaction does take place to give a low yield of 29 .
Tert-Butyldimethylsilyloxytrichloromethylmethane-readily accessible and robust protecting group for (hetero)aryl aldehydes

The tert-butyldimethylsilyloxytrichloromethylmethane (TBSTCM) substituent serves as a readily accessible masking group for aromatic and heteroaromatic aldehydes. The TBSTCM substituent is compatible with a range of common reagents and offers several strategic advantages over alternative aldehyde protecting groups.
Conversion of substituted benzyl ethers to diarylmethanes. A direct synthesis of diarylbenzofurans

Abstract The Lewis acid catalyzed rearrangement of substituted benzyl ethers affords diarylmethanes in good yields. One of the products was converted into a diarylbenzofuran using a benzoylation/P4- t Bu cyclization protocol.
Cold Acclimation of Trogoderma granarium Everts Is Tightly Linked to Regulation of Enzyme Activity, Energy Content, and Ion Concentration.

In this study, cold hardiness and some physiological characteristics of the Khapra beetle, Trogoderma granarium Everts (Coleoptera: Dermestidae) larvae were investigated under different thermal regimes, i.e. control, cold-acclimated (CA), fluctuating-acclimated (FA) and rapid cold-hardened (RCH). In all the regimes, the larval survival rate decreased with a decrease in temperature. Cold acclimated larvae showed the highest cold hardiness following 24 h exposure at -15 and -20 oC. Control larvae had the highest glycogen content (34.4 ± 2.3 µg/dry weight). In contrast, cold acclimated larvae had the lowest glycogen content (23.0 ± 1.6 µg/dry weight). Change in trehalose content was reversely proportional to change in glycogen content. The highest myo-inositol and glucose contents were detected in cold acclimated larvae (10.7 ± 0.4 µg/dry weight) and control (0.49 ± 0.03 µg/dry weight), respectively. In control and treated larvae, [Na+] decreased, though [K+] increased, with increasing the exposure time. A shape of the thermal reaction of AMP-depended protein kinase and protein phosphatase 2C followed the same norm, which was different from protein phosphatase 1 and protein phosphatase 2A. Protein phosphatase 2A and 2C showed a complete difference in thermal reaction norms. Indeed, thermal fluctuation caused the highest changes in the activity of the enzymes, whereas the RCH showed the lowest changes in the activity of the enzymes. Our results showed a significant enhancement of larval cold tolerance under CA regime that is related to the high levels of low molecular weight carbohydrates under this regime. Our results showed that among the different thermal regimes tested, the cold acclimated larvae had the lowest supercooling point (about -22 oC) and the highest cold hardiness following 24 h exposure at -15 and -20 oC.
Highly Emissive Hexanuclear Rhenium(III) Clusters Containing the Cubic Cores [Re6S8]2+ and [Re6Se8]2+

Clusters based on the cubic, hexanuclear rhenium(III) core [Re6(μ3-Q)8]2+ (Q = S, Se) emit red phosphorescence with microsecond-scale lifetimes. Emission quantum yields of 16 clusters range from 1%...
Induced Intramolecularity: An Effective Strategy in Catalysis

The use of reversibly formed covalent bonds to induce intramolecular reactions is a powerful way of controlling regio- and stereoselectivity, as well as accelerating reactions. Although this mode of activation was demonstrated in catalytic systems over 60 years ago, it is infrequently used in catalyst design. This review will focus on highlighting examples of reversible covalent bonding in organic catalysts as well as ligands for metal catalysis. A key aspect of this type of catalysis is that it is an entropically driven process, so it has the potential to be applied to a broad variety of reactions. Furthermore, this design element can be used in concert with more traditional forms of catalyst activation.
BioVR: a platform for virtual reality assisted biological data integration and visualization

Functional characterization of single nucleotide variants (SNVs) involves two steps, the first step is to convert DNA to protein and the second step is to visualize protein sequences with their structures. As massively parallel sequencing has emerged as a leading technology in genomics, resulting in a significant increase in data volume, direct visualization of SNVs together with associated protein sequences/structures in a new user interface (UI) would be a more effective way to assess their potential effects on protein function. We have developed BioVR, an easy-to-use interactive, virtual reality (VR)-assisted platform for integrated visual analysis of DNA/RNA/protein sequences and protein structures using Unity3D and the C# programming language. It utilizes the cutting-edge Oculus Rift, and Leap Motion hand detection, resulting in intuitive navigation and exploration of various types of biological data. Using Gria2 and its associated gene product as an example, we present this proof-of-concept software to integrate protein and nucleic acid data. For any amino acid or nucleotide of interest in the Gria2 sequence, it can be quickly linked to its corresponding location on Gria2 protein structure and visualized within VR. Using innovative 3D techniques, we provide a VR-based platform for visualization of DNA/RNA sequences and protein structures in aggregate, which can be extended to view omics data.
Formation and characterization of C60He

It is shown that kilovolt collisions of C 60 + with helium result in not only the expected dissociation to yield smaller fragment carbon cluster ions but also the formation of fullerene-helium adduct ions corresponding to CxHe+, where x is even and varies from 48 to 58, in agreement with Schwarz et al. This report provides the first unambiguous identification of the C60He+ product, indicating that the helium adduct formation does not require fragmentation. Using hybrid tandem mass spectrometric techniques the mechanism of the formation of these unusual adduct species was investigated. The nature of the collisions, the energetics of the process, and the products of dissociation of C60He+, provide strong evidence that the helium atom is inside the fullerene cage structure.
Studies towards the total synthesis of hygrocins A and B

The western segment of hygrocins A–B has been synthesized through the coupling of a chiral C5–C13 synthon with the sterically demanding hexasubstituted naphthalenic core. The C5–C13 chiral fragment has been assembled via a stereoselective Johnson orthoester rearrangement of an optically pure allylic alcohol derived from d-glucose. Our studies lay the platform for the determination of the absolute configuration of the unassigned C8-stereocenter of the title compounds in addition to the completion of the total synthesis of the unique ansamacrolides hygrocins A and B.
(+)-(18-Crown-6)-2,3,11,12-tetracarboxylic acid and its Ytterbium(III) complex as chiral NMR discriminating agents

The compound (+)-(18-crown-6)-2,3,11,12-tetracarboxylic acid (I) and its ytterbium(III) complex are evaluated as chiral NMR discriminating agents. The crown ether is a useful chiral discriminating agent for protonated amino acid esters, amines, and amino alcohols. The crown can also be used with neutral primary amines since amines are protonated through a neutralization reaction with a carboxylic acid moiety of the crown. Enantiodiscrimination with the crown is observed in methanol and acetonitrile. Addition of ytterbium(III) nitrate to crown−substrate mixtures causes upfield shifts in the NMR spectrum of the substrate and often enhances the enantiomeric discrimination. Evidence indicates that the ytterbium(III) bonds to the carboxylic acid moieties of the crown, but enhancements in enantiomeric discrimination result from either the different association constants of the enantiomers with the crown or diastereomeric nature of the resulting crown−substrate complexes. The ytterbium complex with the crown is ...
Tellurium-mediated cycloaromatization of acyclic enediynes under mild conditions.

The cycloaromatization of acyclic enediynes typically requires very high temperatures (>160 °C) and dilute conditions to proceed in a synthetically useful yield. These conditions hinder reaction throughput, inhibiting the use of this reaction for the large-scale production of materials. The reaction of sodium telluride with acyclic arenediynes yields the corresponding tellurepine, which under gentle heating extrudes Te° to yield the cycloaromatization product. We have developed conditions that form sodium telluride from inexpensive tellurium metal in situ, and that also perform the desilylation of silylated arenediynes in the same process. Under our conditions, we are able to perform desilylation and cycloaromatization at temperatures as low as 40 °C and on a scale as large as 5 g in standard laboratory glassware.
Synthesis of a wakayin model compound: Oxidative formation of a new pyrrole ring in the indol-3-yl-indoloquinone system

Abstract The oxidative formation of a new pyrrole ring in the indol-3-yl-indoloquinone system afforded a simple synthesis of the wakayin model compound 2b.
An imine addition/ring-closing metathesis approach to the spirocyclic core of halichlorine and pinnaic acid.

An approach to the spirocyclic core of halichlorine and pinnaic acid has been designed around an imine allylation/ring-closing metathesis sequence. This sequence has been used to generate several azabicylo[n.5] model systems. A newly reported metathesis catalyst was show to be highly effective for cyclization of these systems.
An Exceptionally Short and Simple Enantioselective Total Synthesis of Pentacyclic Triterpenes of the β-Amyrin Family

A new and very direct enantioselective total synthesis of members of the β-amyrin family of pentacyclic triterpenes has been developed starting with acylsilane 5, 2-propenyllithium, and cyclohexenylmethyl bromide 6, which were assembled to form tetraene 7. Cationic cyclization of 7 and silylation afforded 8, which after vinyl triflate formation was cyclized via a Cu(I) intermediate (Scheme 2) to form the TBS ether of aegiceradienol 10, a versatile intermediate that is readily converted into natural β-amyrins such as β-amyrin (1) and oleanolic acid (2). The C(14)-diastereomer (13) of aegiceradienol was also synthesized from the C(14)-diastereomer of 8 using an intramolecular Stille reaction for the closure of ring D (Scheme 4).
Synthesis and opioid binding properties of 2-chloroacrylamido derivatives of 7,8-dihydromorphinans

Abstract 14β-2-chloroacrylamido-7,8-dihydromorphinones 7 and 8 and the corresponding 6β-7,8-dihydromorphinans 19 and 20 were prepared and the binding affinities to μ, δ and κ receptors in bovine striatal membranes were determined. Only 20 produced wash-resistant inhibition of m binding despite the fact that it formed adducts with N-acetylcysteine at pH 10 and not at pH 8.
Complex dietary polysaccharide modulates gut immune function and microbiota, and promotes protection from autoimmune diabetes

The dietary supplement and prebiotic values of β-glucan-rich products have been widely recognized and dietary approaches for modulating autoimmunity have been increasingly explored, we assess the impact of oral administration of high-purity yeast β-glucan (YBG) on gut immune function, microbiota and type 1 diabetes (T1D) using mouse models. Oral administration of this non-digestible complex polysaccharide caused a dectin-1-dependent immune response involving increased expression of interleukin-10 (IL-10), retinaldehyde dehydrogenase (Raldh) and pro-inflammatory cytokines in the gut mucosa. YBG-exposed intestinal dendritic cells induced/expanded primarily Foxp3+ , IL-10+ and IL-17+ T cells, ex vivo. Importantly, prolonged oral administration of low-dose YBG at pre-diabetic stage suppressed insulitis and significantly delayed the appearance of T1D in non-obese diabetic (NOD) mice. Further, prolonged treatment with YBG showed increased Foxp3+ T-cell frequencies, and a significant change in the gut microbiota, particularly an increase in the abundance of Bacteroidetes and a decrease in the Firmicute members. Oral administration of YBG, together with Raldh-substrate and β-cell antigen, resulted in better protection of NOD mice from T1D. These observations suggest that YBG not only has a prebiotic property, but also an oral tolerogenic-adjuvant-like effect, and these features could be exploited for modulating autoimmunity in T1D.
7-Pyridylindoles: synthesis, structure, and properties.

A series of three isomeric 7-pyridylindoles (7-PIs) are prepared where the pyridine attachment is through C2, C3, or C4. These systems are prepared by a combination of the Bartoli reaction and the Stille coupling with an appropriate pyridyl stannane. By treatment with CH3I, the 7-PIs can be converted to their pyridinium salts. Deprotonation at the NH of these salts leads to a zwitterion which, in the 4-pyridyl system, also exists as a neutral isomer. The photophysical and NMR properties of these systems are discussed. All three pyridylindoles are analyzed by X-ray crystallography and shown to exist in different states of aggregation dictated by the formation of intra- and intermolecular H-bonds.
Transition metal η2-vinyl complexes

Abstract Transition metal η 2 -vinyl complexes, L n M(η 2 -CRCR 2 ), adopt structures in which both alkenyl carbons are bound to the metal. The M(CRCR 2 ) unit is not planar in these 1-metallocyclopropene complexes. Instead, the CR 2 entity is twisted by ca. 90° away from planarity with the three-membered ring formed by M, C α , and C β . The ring carbons of η 2 -vinyl ligands are bound asymmetrically to the metal with one short metal–carbon bond and one long metal–carbon bond. These geometrical features reflect double bond character between C α and the metal at the expense of the carbon–carbon double bond in the classic organic vinyl moiety. Coordination of both carbons of the four-electron donating η 2 -vinyl ligand increases the electron count at the metal by two electrons relative to an η 1 -bound vinyl ligand. This review summarizes synthetic methods which yield η 2 -vinyl complexes, describes bonding and structural characteristics of η 2 -vinyl ligands, tabulates NMR spectroscopic signatures of η 2 -vinyl ligands, and outlines reactions of this growing class of compounds.
Enantioselective syntheses of isoaltholactone, 3-epi-altholactone, and 5-hydroxygoniothalamin.

A flexible enantioselective route to highly functionalized α,β-unsaturated δ-lactones has allowed for the syntheses of the styryllactones: isoaltholactone, 3-epi-altholactone, and 5-hydroxygonioth...
Single-molecule RNA folding.

Single-molecule experiments significantly expand our capability to characterize complex dynamics of biological processes. This relatively new approach has contributed significantly to our understanding of the RNA folding problem. Recent single-molecule experiments, together with structural and biochemical characterizations of RNA at the ensemble level, show that RNA molecules typically fold across a highly rugged energy landscape. As a result, long-lived folding intermediates, multiple folding pathways, and heterogeneous conformational dynamics are commonly found for RNA enzymes. While initial results have suggested that stable secondary structures are partly responsible for the rugged energy landscape of RNA, a complete mechanistic understanding of the complex folding behavior has not yet been obtained. A combination of single-molecule experiments, which are well suited to analyze transient and heterogeneous dynamic behaviors, with ensemble characterizations that can provide structural information at a s...
Synthesis and structure of [PPh4]3[Cr(Te4)3].DMF: The first tris(tetratelluride) complex

The compound [PPh(4)](3)[Cr(Te(4))(3)].DMF has been synthesized from the reaction of Cr(CO)(6) with a polytelluride solution in dimethylformamide at 100 degrees C. The compound has been characterized by (125)Te NMR and single-crystal X-ray diffraction techniques. The compound crystallizes in the triclinic space group P(-)1, with a = 12.991(3) A, b = 14.782(3) A, c = 24.628(5) A, alpha= 90.63(3)o, beta= 104.45(3)o, gamma= 106.49(3)o, and Z = 2 (T = 153 K). The [Cr(Te(4))(3)](3-) anion consists of a Cr(III) center chelated by three Te(4)(2-) ligands in a distorted octahedral environment. The anion has the Deltalambdalambdalambda (or Lambdadeltadeltadelta) conformation.
P[N(i-Bu)CH2CH2]3N: a versatile ligand for the Pd-catalyzed amination of aryl chlorides.

Palladium-catalyzed amination reactions of aryl chlorides with amines proceeded in the presence of the bicyclic triaminophosphine P[N(i-Bu)CH2CH2]3N to afford the corresponding arylamines in good to excellent yields. Electron-poor, electron-neutral, and electron-rich aryl chlorides all participated with equal ease.
A nickel precatalyst for efficient cross-coupling reactions of aryl tosylates with arylboronic acids: vital role of dppf

Abstract An air-stable and easy-to-handle nickel precatalyst, (9-phenanthrenyl)Ni(II)(PPh3)2Cl, was examined for the cross-coupling reactions of aryl tosylates with arylboronic acids. Under the optimized reaction conditions, the catalytic system tolerates a wide range of activated, neutral and deactivated substrates. The selectivity of this cross-coupling reaction towards aryl tosylates and arylboronic acids has been investigated. It is proposed that ligand 1,1′-bis(diphenylphosphino)ferrocene (dppf) plays a key role in the coupling by enforcing a cis geometry in key intermediates and the active Ni(0) species.