Inverse Pairs Research Articles

Visualization of membrane localization and the functional state of CB2R pools using matched agonist and inverse agonist probe pairs.

The diversity of physiological roles of the endocannabinoid system has turned it into an attractive yet elusive therapeutic target. However, chemical probes with various functionalities could pave the way for a better understanding of the endocannabinoid system at the cellular level. Notably, inverse agonists of CB2R - a key receptor of the endocannabinoid system - lagged behind despite the evidence regarding the therapeutic potential of its antagonism. Herein, we report a matched fluorescent probe pair based on a common chemotype to address and visualize both the active and inactive states of CB2R, selectively. Alongside extensive cross-validation by flow cytometry, time-lapse confocal microscopy, and super-resolution microscopy, we successfully visualize the intracellular localization of CB2R pools in live cells. The synthetic simplicity, together with the high CB2R-selectivity and specificity of our probes, turns them into valuable tools in chemical biology and drug development that can benefit the clinical translatability of CB2R-based drugs.

7-Deaza-2'-deoxyisoguanosine, a Noncanonical Nucleoside for Nucleic Acid Code Expansion and New DNA Constructs: Nucleobase Functionalization of Inverse Watson-Crick and Purine-Purine Base Pairs.

7-Deaza-2'-deoxyisoguanosine forms stable inverse Watson-Crick base pairs with 5-methyl-2'-deoxyisocytidine and purine-purine base pairs with 2'-deoxyguanosine or 5-aza-7-deaza-2'-deoxyguanosine. Both base pairs expand the genetic coding system. The manuscript reports on the functionalization of these base pairs with halogen atoms and clickable side chains introduced at 7-position of the 7-deazapurine base. Oligonucleotides containing the functionalized base pairs were prepared by solid-phase synthesis. To this end, a series of phosphoramidites were synthesized and clickable side chains with short and long linkers were incorporated in oligonucleotides. Fluorescent pyrene conjugates were obtained by postmodification. Functionalization of DNA with a single inverse Watson-Crick base pair by halogens or clickable residues has only a minor impact on duplex stability. Pyrene click adducts increase (long linker) or decrease (short linker) the double helix stability. Stable hybrid duplexes were constructed containing three consecutive purine-purine pairs of 7-functionalized 7-deaza-2'-deoxyisoguanine with guanine or 5-aza-7-deazaguanine in the center and Watson-Crick pairs at both ends. The incorporation of a hybrid base pair tract of 7-deaza-2'-deoxyisoguanosine/5-aza-7-deaza-2'-deoxyguanosine pairs stabilizes the double helix strongly. Fluorescence intensity of pyrene short linker adducts increased when the 7-deazapurine base was positioned opposite to 5-methylisocytosine (inverse base pair) compared to purine-purine base pairs with guanine or 5-aza-7-deazaguanine in opposite positions. For long liker adducts, the situation is more complex. Circular dichroism (CD) spectra of purine DNA differ to those of Watson-Crick double helices and are indicative for the new DNA constructs. The impact of 7-deaza-2'-deoxyisoguanine base pair functionalization is studied for the first time and all experimental details are reported to prepare DNA functionalized at the 7-deazaisoguanine site. The influence of single and multiple incorporations on DNA structure and stability is shown. Clickable residues introduced at the 7-position of the 7-deazaisoguanine base provide handles for Huisgen-Sharpless-Meldal click cycloadditions without harming the stability of purine-pyrimidine and purine-purine base pairs. Other chemistries might be used for bioconjugation. Our investigation paves the way for the functionalization of a new DNA related recognition system expanding the common Watson-Crick regime.

Half-exceeded Symmetric Permutations and the Inverse Pairs

In this paper, we introduce a class of restricted symmetric permutations, called half-exceeded symmetric permutations. We deduce the enumerative formula of the permutations of { 1 , 2 , … , 2 n } and give it a refinement according to the distribution of the inverse pairs. As a consequence, we obtain new combinatorial interpretations of some well-known sequences, such as Stirling numbers of the second kind and ordered Bell numbers. Moreover, we introduce the ordered Stirling number of the second kind and establish a combinatorial proof of the recursive relation of the sequence.

Reciprocal Symmetry via Inverse Series Pairs

Reciprocal series are employed to systematically review convolution sums, orthogonality relations, recurrence relations and reciprocal formulae for several classical number sequences, such as binomial coefficients, Stirling numbers, Bernoulli numbers, and Euler numbers.

Temperature uniformity characteristics of array jet impingement cooling with the maximum cross-flow scheme

Temperature uniformity of the impingement cooling is commonly needed in many fields in order to enhance performance, reliability, and to ensure material quality. In particular, operating life of the hot components in gas turbine depends heavily on how uniformly they are being cooled to mitigate the development of thermal stresses. However, there are rather limited literatures addressing these, and the cooling uniformities of jet impingement in extreme conditions, such as the cooling of turbine vane and combustor liner, are seldom discussed. This study focused on the temperature uniformity of array jet impingement cooling with the maximum crossflow scheme, where the detailed distribution of the nonuniformly cooled areas on the target wall, as well as their correlations with the impinging flow field, and the effects of typical geometrical and fluid parameters on the uniformity were investigated. Results indicated that the arising of the high temperature zones and inverse temperature gradient pairs around them, essentially induced by the entrainment vortex and counter rotating vortex pair in the streamwise and spanwise directions respectively, are the sources of temperature nonuniformities over the impingement target surface. Moreover, increasing the impingement Reynolds number or shortening the jet-to-target spacing for higher jet Reynolds numbers could improve the temperature uniformity.

A general matrix series inversion pair and associated polynomials

Abstract In the present work, a pair of general inverse matrix series relations is established, and thereby a general class of matrix polynomials is introduced. This class generalizes the extended Jacobi polynomials and their particular cases such as the polynomials of Brafman, Jacobi, Chebyshev, and Legendre. It is further shown that this pair also gives rise to the matrix forms of the Wilson polynomials and the Racah polynomials. For these polynomials, the generating matrix function relations as well as the matrix summation formulas are deduced from their respective inverse pairs. Certain inverse pairs belonging to the Gould classes and the Legendre-Chebyshev classes due to John Riordan [An Introduction to Combinatorial Identities, Wiley, 1968] are also extended to matrix forms.

Invertible skew pairings and crossed products for weak Hopf algebras

In this paper we work with invertible skew pairings for weak bialgebras in a symmetric monoidal category where every idempotent morphism splits. We prove that this kind of skew pairings induces examples of weak distributive laws and therefore they provide weak wreath products. Also we will show that they define weakly comonoidal mutually weak inverse pairs of weak distributive laws and, by the results proved by G. Böhm and J. Gómez-Torrecillas, we obtain weak wreath products that become weak bialgebras with respect to the tensor product coalgebra structure. As an application, we will show that the Drinfel'd double of a finite weak Hopf algebra can be constructed using the weak wreath product associated to an invertible $1$-skew pairing.

Leveraged ETF Pairs: An Empirical Evaluation of Portfolio Performance

We examine the performance of investment strategies involving leveraged and inverse leveraged ETF pairs. As in Jiang and Peterburgsky’s (2017) simulation analysis, the empirical analysis in this article indicates that simple portfolios of bull/bear short positions constructed to approximately mimic an underlying index (such as the S&amp;P 500) outperform the index on a risk-adjusted basis. The outperformance asymptotically diminishes as the investor’s rebalance bounds tighten. Additionally, results indicate that the volatility effect dominates the trend effect for bull leveraged ETFs. This finding is relevant for the debate on the regulation of leveraged ETF markets. <b>Key Findings</b> ▪ Simple portfolios of bull/bear short positions in leveraged and inverse leveraged ETFs constructed to approximately mimic an underlying index (such as the S&amp;P 500) outperform the index on a risk-adjusted basis. ▪ The outperformance asymptotically diminishes as the investor’s rebalance bounds tighten. ▪ The volatility effect dominates the trend effect for bull leveraged ETFs.

A general inverse matrix series relation and associated polynomials – II

Abstract We propose a matrix analogue of a general inverse series relation with an objective to introduce the generalized Humbert matrix polynomial, Wilson matrix polynomial, and the Rach matrix polynomial together with their inverse series representations. The matrix polynomials of Kiney, Pincherle, Gegenbauer, Hahn, Meixner-Pollaczek etc. occur as the special cases. It is also shown that the general inverse matrix pair provides the extension to several inverse pairs due to John Riordan [An Introduction to Combinatorial Identities, Wiley, 1968].

On Decomposition Formulas Related to the Gaussian Hypergeometric Functions in Three Variables

In this paper, by using certain inverse pairs of symbolic operators introduced by Choi and Hasanov in 2011, we establish several decomposition formulas associated with the Gaussian triple hypergeometric functions. Some transformation formulas for these functions have also been obtained.

Decomposition formulas for some quadruple hypergeometric series

In the present work, the authors obtained operator identities and decomposition formulas for second order Gauss hypergeometric series of four variables into products containing simpler hypergeometric functions. A Choi–Hasanov method based on the inverse pairs of symbolic operators is used. The obtained expansion formulas for the hypergeometric functions of four variables will allow us to study the properties of these functions. These decompositions are used to study the solvability of boundary value problems for degenerate multidimensional partial differential equations.

DECOMPOSITION FORMULAS WITH OPERATORS H FOR SECOND-ORDER GAUSS HYPERGEOMETRIC SERIES OF FOUR VARIABLES

In this paper decomposition formulas and operator identities for second-order Gauss hypergeometric series of four variables in products of simpler known hypergeometric functions were obtained. The Choi - Hasanov method is used, based on inverse pairs of symbolic operators H(a,c) and H¯¯¯¯¯(a,c) introduced in 2011 in the article of Junesang Choi, Anvar Hasanov «Applications of the operator H(a,c) to the Humbert double hypergeometric functions». The obtained expansion formulas for hypergeometric functions of four variables will allow us to study the properties of these functions. By means of these expansions we can investigate the solvability of some boundary value problems for partial differential equations.

Split radiographic tracer technique to measure the full width of a high energy density mixing layer

We describe a new radiography–based technique for measuring the width of the mixing layer that develops when high–energy–density (HED) fluids of different density mix at an interface. In a traditional radiography target, the denser material includes an embedded, density–matched, high opacity, tracer layer to focus the radiograph on a 2D slice of the 3D flow field. The high opacity layer enhances the contrast between the dense and light materials that permits a clear identification of the spike front, i.e. penetration of the dense material into the light material, but obscures the bubble front, i.e. penetration of the light material into the heavy when the fluids are highly interpenetrated, as in a turbulent mixing layer. On the other hand, removing the tracer layer makes it difficult to identify the interface at all, due to poor contrast and an increased susceptibility to edge effects. Our solution is a split tracer approach where half the target uses the traditional geometry while the other half utilizes a special tracer layer in the light material to produce a radiograph with inverse x-ray opacity characteristics when backlit at a specified x–ray energy. Hydrodynamic equivalency is maintained between the two halves of the target. By making a single target with the traditional and inverse material pairs set side-by-side, we are able to simultaneously measure the penetration of bubbles and spikes in a deeply nonlinear flow, yielding the full mix width. We discuss this new target concept and present our first experiments at the National Ignition Facility (NIF) demonstrating the viability of this technique.

Leveraged ETF Pairs: An Empirical Evaluation of Portfolio Performance

This paper examines the performance of investment strategies involving leveraged and inverse leveraged ETF pairs. As in Jiang and Peterburgsky’s (2017) simulation analysis, the empirical analysis in this paper indicates that simple portfolios of bull/bear short positions constructed to approximately mimic an underlying index (such as the S&P 500) outperform the index on a risk-adjusted basis. The outperformance asymptotically diminishes as the investor’s rebalance bounds tighten. Additionally, the results support the theoretical positive relationship between outperformance and index standard deviation and negative relationship between outperformance and index absolute return.

Investment performance of shorted leveraged ETF pairs

ABSTRACTWe analyze investment strategies involving triple-leveraged and inverse triple-leveraged ETF pairs by simulating daily returns over a 48-year period. Our results show that many such strategies significantly outperform the S&P 500 on a risk-adjusted basis. For example, when shorting the bear triple-leveraged ETF and the bull triple-leveraged ETF in a 2:1 proportion (while going long Treasuries), we find that the average annual Sharpe ratio is more than four times higher than for the S&P 500 and that the strategy outperforms the S&P 500 in 43 of the 48 years. Our results are robust to variations in bear/bull proportions, rebalance thresholds, and underlying parameters.

Relational Priming Based on a Multiplicative Schema for Whole Numbers and Fractions.

Why might it be (at least sometimes) beneficial for adults to process fractions componentially? Recent research has shown that college-educated adults can capitalize on the bipartite structure of the fraction notation, performing more successfully with fractions than with decimals in relational tasks, notably analogical reasoning. This study examined patterns of relational priming for problems with fractions in a task that required arithmetic computations. College students were asked to judge whether or not multiplication equations involving fractions were correct. Some equations served as structurally inverse primes for the equationthat immediately followed it (e.g., 4×3/4=3 followed by 3×8/6=4). Students with relatively high math ability showed relational priming (speeded solution times to the second of two successive relationally related fraction equations) both with and without high perceptual similarity (Experiment 2). Students with relatively low math ability also showed priming, but only when the structurally inverse equationpairs were supported by high perceptual similarity between numbers (e.g., 4×3/4=3 followed by 3×4/3=4). Several additional experiments established boundary conditions on relational priming with fractions. These findings are interpreted in terms of componential processing of fractions in a relational multiplication context that takes advantage of their inherent connections to a multiplicative schema for whole numbers.

Tensor-splitting properties of $n$-inverse pairs of operators

In this paper we study n-inverse pairs of operators on the tensor product of Banach spaces. In particular we show that an n-inverse pair of elementary tensors of operators on the tensor product of two Banach spaces can arise only from l- and m-inverse pairs of operators on the individual spaces. This gives a converse to a result of Duggal and Muller, and proves a conjecture of the second named author. Our proof uses techniques from algebraic geometry, which generalize to other relations among operators in a tensor product. We apply this theory to obtain results for n-symmetries in a tensor product as well.

Influence of the materials employed on the wear of frictional components

Wear of direct and inverse frictional pairs made of heat-resistant alloy and titanium-carbide cermet is investigated. In inverse frictional pairs, the wear of the larger surface is due to adhesion and fatigue. In direct frictional pairs, greater wear is observed and may be attributed to abrasive and mechanical factors.

Investment Performance of Shorted Leveraged ETF Pairs

We analyze trading strategies involving triple-leveraged and inverse triple-leveraged ETF pairs by simulating daily returns over a 48 year period. Our results show that many such strategies significantly outperform the S&P 500 on a risk-adjusted basis. The Sharpe ratio appears to be maximized when shorting the bear triple-leveraged ETF and the bull triple-leveraged ETF in a 2:1 proportion, and simultaneously holding Treasuries long. In this case we find that the average annual Sharpe ratio is more than four times higher than for the S&P 500, and that the strategy outperforms the market in 43 of the 48 years.

Discerning Temporal Expectancy Effects in Script Processing: Evidence from Pupillary and Eye Movement Recordings

Accessing the temporal position of events (early or late in the event sequence) can influence the generation of predictions about upcoming events. However, it is unclear how the temporal position is processed strategically. To investigate this, we presented event pairs to 23 healthy volunteers manipulating temporal order (chronological, inverse) and temporal position (early, late). Pupil dilation, eye movements, and behavioral data, showed that chronological and early event pairs are processed with more ease than inverse and late event pairs. Indexed by the pupillary response late events and inversely presented event pairs elicited greater cognitive processing demands than early events and chronologically presented event pairs. Regarding eye movements, fixation duration was less sensitive to temporal position than to temporal order. Looking at each item of the event sequence only once was behaviorally more effective than looking multiple times at each event regardless of whether temporal position or temporal order was processed. These results emphasize that accessing temporal position and temporal order information results in dissociable behavioral patterns. While more cognitive resources are necessary for processing late and inverse items, change of information acquisition strategies turns out to be most effective when temporal order processing is required.