Universal Signature Research Articles

Curtailing their negativity.

The longstanding ‘polyelectrolyte theory of the gene’ proposes that a multiply charged backbone is the universal signature of all genetic polymer systems that support life. Now, the first tenable challenge to this theory has been mounted, through the successful engineering of enzymes which can synthesize and reverse-transcribe from an artificial, uncharged nucleic acid analogue.

Signcryption schemes with insider security in an ideal permutation model

Abstract Signcryption aims to provide both confidentiality and authentication of messages more efficiently than performing encryption and signing independently. The “Commit-then-Sign & Encrypt” (CtS&E) method allows to perform encryption and signing in parallel. Parallel execution of cryptographic algorithms decreases the computation time needed to signcrypt messages. CtS&E uses weaker cryptographic primitives in a generic way to achieve a strong security notion of signcryption. Various message pre-processing schemes, also known as message padding, have been used in signcryption as a commitment scheme in CtS&E. Due to its elegance and versatility, the sponge structure turns out to be a useful tool for designing new padding schemes such as SpAEP [T. K. Bansal, D. Chang and S. K. Sanadhya, Sponge based CCA2 secure asymmetric encryption for arbitrary length message, Information Security and Privacy – ACISP 2015, Lecture Notes in Comput. Sci. 9144, Springer, Berlin 2015, 93–106], while offering further avenues for optimization and parallelism in the context of signcryption. In this work, we design a generic and efficient signcryption scheme featuring parallel encryption and signature on top of a sponge-based message-padding underlying structure. Unlike other existing schemes, the proposed scheme also supports arbitrarily long messages. We prove the construction secure when instantiated from weakly secure asymmetric primitives such as a trapdoor one-way encryption and a universal unforgeable signature. With a careful analysis and simple tweaks, we demonstrate how different combinations of weakly secure probabilistic and deterministic encryption and signature schemes can be used to construct a strongly secure signcryption scheme, further broadening the choices of underlying primitives to cover essentially any combination thereof. To the best of our knowledge, this is the first signcryption scheme based on the sponge structure that also offers strong security using weakly secure underlying asymmetric primitives, even deterministic ones, along with the ability to handle long messages, efficiently.

The 19 September 2017 (Mw7.1) Intermediate‐Depth Mexican Earthquake: A Slow and Energetically Inefficient Deadly Shock

AbstractWe investigate dynamic source parameters of the Mw7.1 Puebla‐Morelos intermediate‐depth earthquake (h = 57 km) of 19 September 2017, which devastated Mexico City. Our simple, elliptical source model, coupled with a new Particle Swarm Optimization algorithm, revealed rupture propagation within the subducted Cocos plate, featuring a high stress drop (Δτ = 14.9±5.6 MPa) and a remarkably low radiation efficiency (ηr = 0.16 ± 0.09). Fracture energy was large (G = (1.04 ± 0.3) × 1016 J), producing a slow dissipative rupture (Vr/Vs = 0.34 ± 0.04) with scaling‐consistent radiated energy (Er = (1.8 ± 0.9)·1015 J) and energy‐moment ratio (Er/M0 = 3.2 × 10−5). About 84% of the available potential energy for the dynamic rupture was dissipated in the focal region, likely producing friction‐induced melts in the fault core of 0.2–1.2 cm width due to heat production (700–1200 °C temperature rise). Such source features seem to be a universal signature of intermediate‐depth earthquakes.

Replication-independent mutations: a universal signature?

A recommendation of: Guillaume Achaz, Serge Gangloff, Benoit Arcangioli The quiescent X, the replicative Y and the Autosomes 10.1101/351288

Signature of van der Waals interactions in the cumulant density matrix.

Here we propose and implement a universal signature of the van der Waals interactions based on the cumulant part of the two-electron reduced density matrix (2-RDM). Due to the connected property of the cumulant, we can use it to detect the van der Waals interactions between two molecular moieties. In particular, we use the squared Frobenius norm of the cumulant of the 2-RDM, which has been previously shown to provide a size-extensive measure of the electron correlation. As two moieties are separated to infinity, the cumulant Frobenius norm exhibits an r-6 decay to its asymptotic limit, providing a density-based measure of the van der Waals interaction. We study this signature of van der Waals forces in a collection of small molecules of varying geometries. These computations agree with experimental trends of known literature values.

Universal oscillatory dynamics in capillary filling

Capillary filling dynamics is ubiquitous in biological and natural processes. While capillary imbibition in narrow conduits has been extensively studied in the literature, any generalization in the oscillatory characteristics of the capillary front, typically observed towards the end of capillary filling processes, remains elusive. Considering Newtonian fluids, here, we demonstrate the realization of a unique universal signature of the oscillatory dynamics of the capillary front, by collapsing all relevant data in terms of the pertinent dimensionless parameters, leading to a single master curve. We further delineate the validity of our claim through extensive experiments, using four different fluids, and phase-field numerical simulations. These results may bear far reaching consequences towards explaining the capillary filling processes in a wide variety of applications ranging from nature to energy.

The potential of BRAF-associated non-coding RNA as a therapeutic target in melanoma

ABSTRACTIntroduction: The advent of targeted therapies and immune checkpoints inhibitors has enhanced the treatment of metastatic melanomas. Despite striking improvements of patients’ survival, drug resistance continues to limit the efficacy of such treatments. Genetic and nongenetic/adaptive mechanisms of resistance could be involved; in the latter mechanism, noncoding RNAs (ncRNAs) are emerging as key players.Areas covered: This article outlines the current knowledge of ncRNA involvement in BRAF-mutant melanomas and the development of resistance to targeted/immunotherapies. We also discuss how ncRNAs can be exploited for the development of therapeutic and diagnostic approaches.Expert opinion: ncRNAs can be envisaged as powerful diagnostics and therapeutics. Despite progress in our knowledge about their deregulation in cancer, it is still difficult to derive universal and robust ncRNAs unique signatures of malignancy for diagnostic purposes, which need validation in large cohort of patients. Also, ncRNA specific targeting to melanoma cells in vivo requires the development of improved systemic delivery tools. In this regard, the development of stable nanodelivery particles seems to offer renewed hope for success in the clinic.

Rotating hollow patterns in fluids

Stable rotating polygonal hollow patterns were predicted theoretically and measured for Leidenfrost drops confined by circular boundary. Liquid free surface modes occur with different number of edges. This two-dimensional incompressible and inviscid flow is controlled by surface tension, evaporation reaction and gravitation. The model is based on shallow water theory and predicts the existence of sharp rotational polygonal waves as solitary waves solutions. These patterns may represent a signature of universality in shallow water rotating models since similar rotating hollow polygons are noticed in tropical cyclones, fast rotated liquids, Saturn's hexagon, and some plasma systems.

The importance of kelp to an intertidal ecosystem varies by trophic level: insights from amino acid δ13C analysis

AbstractA fundamental question in ecology is understanding how energy and nutrients move through and between food webs, and which sources of production support consumers. In marine ecosystems, these basic questions have been challenging to answer given the limitation of observational methods. Stable isotope analysis of essential amino acids (EAA δ13C) has great potential as a tool to quantify energy and nutrient flow through marine food webs; however, it has been primarily utilized at large spatial scales. Here, we used EAA δ13C analysis to test for connectivity between adjacent subtidal and intertidal components of a nearshore ecosystem in south central Alaska. We measured δ13C of six EAA from four marine producer groups: subtidal kelp (Laminaria sp.), offshore particulate organic matter (POM), and intertidal red (Neorhodomela sp.) and green (Ulva sp.) algae. In addition, we sampled four intertidal invertebrate consumer species spanning a range of trophic/functional groups: Mytilus sp., Strongylocentrotus droebachiensis, Nucella sp., and Pycnopodia helianthoides. Using canonical analysis of principal coordinates (CAP) and isotope mixing models (MixSIAR), we tested for differences among producer EAA δ13C fingerprints and quantified the contribution of producer EAA to consumers. We compared these results to previously published EAA δ13C data on marine producers to examine the generality of this technique. We found the EAA δ13C fingerprints of subtidal kelps (Laminaria), Ulva, and Neorhodomela were highly distinct from one another. Further, our measured EAA δ13C patterns for kelp and red algae matched those previously reported from other localities, suggesting unique and universal EAA δ13C signatures for these groups. However, CAP could not distinguish between microalgae (POM) and Ulva, possibly due to similar biochemical pathways for the synthesis of EAA. Using these producer fingerprints, we found upper trophic‐level invertebrate consumers, Nucella and Pycnopodia, derived more than 60% of their essential amino acids from subtidal kelps. In contrast, the sampled primary consumers in the system, Mytilus and Strongylocentrotus, relied more heavily on Ulva and/or offshore POM. Our results provide evidence for connectivity between two adjacent nearshore ecosystems and exemplify EAA δ13C as a powerful new tool in tracing energy and nutrient flow within and among marine food webs.

Pinch point singularities of tensor spin liquids

Recently, a new class of three-dimensional spin liquid models have been theoretically discovered, which feature generalized Coulomb phases of emergent symmetric tensor $U(1)$ gauge theories. These ``higher rank'' tensor models are particularly intriguing due to the presence of quasiparticles with restricted mobility, such as fractons. We investigate universal experimental signatures of tensor Coulomb phases. Most notably, we show that tensor Coulomb spin liquids (both quantum and classical) feature characteristic pinch point singularities in their spin-spin correlation functions, accessible via neutron scattering, which can be readily distinguished from pinch points in conventional $U(1)$ spin liquids. These pinch points can thus serve as a crisp experimental diagnostic for such phases. We also tabulate the low-temperature heat capacity of various tensor Coulomb phases, which serves as a useful additional diagnostic in certain cases.

The effect on early renal function of various dynamic preservation strategies in a preclinical pig ischemia-reperfusion autotransplant model.

The aims of this study were to determine the most optimal timing to start machine perfusion during kidney preservation to improve early graft function and to evaluate the impact of temperature and oxygen supply during machine perfusion in a porcine ischemia-reperfusion autotransplant model. The left kidney of an approximately 40-kg female Belgian Landrace pig was exposed to 30 minutes of warm ischemia via vascular clamping and randomized to 1 of 6 study groups: (1) 22-hour static cold storage (SCS) (n = 6), (2) 22-hour hypothermic machine perfusion (HMP) (n = 6), (3) 22-hour oxygenated HMP (n = 7), (4) 20-hour HMP plus 2-hour normothermic perfusion (NP) (n = 6), (5) 20-hour SCS plus 2-hour oxygenated HMP (n = 7), and (6) 20-hour SCS plus 2-hour NP (n = 6). Graft recovery measured by serum creatinine level was significantly faster for continuous HMP preservation strategies compared with SCS alone and for all end-ischemic strategies. The active oxygenated 22-hour HMP group demonstrated a significantly faster recovery from early graft function compared with the 22-hour nonactive oxygenated HMP group. Active oxygenation was also found to be an important modulator of a faster increase in renal flow during HMP preservation. Continuous oxygenated HMP applied from the time of kidney procurement until transplant might be the best preservation strategy to improve early graft function.

Quantum signature of exciton condensation

Exciton condensation, a Bose-Einstein-like condensation of excitons, was recently reported in an electronic double layer (EDL) of graphene. We show that a universal quantum signature for exciton condensation can be used to both identity and quantify exciton condensation in molecular systems from direct calculations of the two-electron reduced density matrix. Computed large eigenvalues in the particle-hole reduced-density matrices of pentacene and hexacene EDLs reveal the beginnings of condensation, suggesting the potential for exciton condensation in smaller scale molecular EDLs.

Resonance in modulation instability from non-instantaneous nonlinearities

To explore resonance phenomena in the nonlinear region, we show by experimental measurements and theoretical analyses that resonance happens in modulation instability from non-instantaneous nonlinearities in photorefractive crystals. With a temporally periodic modulation in the external bias voltage, corresponding to a modulation in the nonlinear strength, an enhancement in the visibility of MI at resonant frequency is reported through spontaneous optical pattern formations. Theoretical curves obtained from a nonlinear non-instantaneous Schrödinger equation give good agreement to experimental data.

Morphological Contributions to Interfacial Charge Trapping and Nongeminate Recombination in Polymer Solar Cells Revealed by UV Light Soaking.

Nongeminate charge recombination occurs over a broad range of time scales in polymer solar cells and represents a serious loss channel for the performance and lifetime of devices. Multiple factors influence this process, including changes in morphology and formation of permanent defects, but individual contributions are often difficult to resolve from conventional experiments. We use intensity modulated photocurrent/photovoltage spectroscopy (IMPS/IMVS) to investigate nongeminate charge recombination in blends of poly[2,6-(4,4-bis-(2-ethylhexyl)-4 H-cyclopenta [2,1- b;3,4- b']dithiophene)- alt-4,7(2,1,3-benzothiadiazole)] (PCPDTBT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) solar cells. PCPDTBT/PCBM devices are exposed to varying doses of UV light resonant with PCBM to induce small perturbations in the thin film morphology, namely local heating. IMPS/IMVS sweeps display signatures unique to degradation, that is, photocurrent and photovoltage leading the excitation light modulation appearing as positive phase shifts or 1st quadrant features in Bode and Nyquist representations, respectively. We assign this component to interface charging at purified PCPDTBT/PCBM phase boundaries that trap mobile charges and facilitate nongeminate recombination. Time- and frequency-domain drift-diffusion simulations are then used to model the perturbed photocurrent responses that show good agreement with experiments. Trap occupancies and their impact of photocurrent production are investigated using variable background (dc) excitation light intensities revealing increases of the 1st quadrant component in devices irradiated for longer times. No evidence of chemical degradation was observed from molecular spectroscopy and imaging experiments, and we conclude that morphological changes are chiefly responsible for larger nongeminate charge recombination yields as devices age. Lastly, we propose that the 1st quadrant IMPS/IMVS is a universal signature of morphology-related degradation, although its relative contribution may vary between material systems.

P-171 - Genome-scale dissection of regulatory network dysfunction in tumors with high NRF2 activity

NRF2 is a cytoprotective transcription factor, yet NRF2 hyperactivating mutations promote oncogenesis. We used an integrative genomics approach to get an unbiased view of gene dysregulation in tumors with oncogenic NRF2 mutations and identified a set of 32 direct NRF2 targets that are consistently upregulated in these tumors. This NRF2 cancer signature includes canonical redox-related NRF2 targets (e.g., NQO1) as well as several genes not previously linked to NRF2; upregulation of this gene set is independent of the organ where the tumor developed. A key distinguishing feature of the NRF2 cancer signature genes is that they are regulated by high affinity NRF2 binding sites (antioxidant response elements) that fall within DNA regions with a ubiquitously permissive chromatin signature. This implies that the NRF2 cancer target genes are broadly responsive to oncogenic NRF2 because they lack the epigenetic restraints that restrict expression of most NRF2 targets. We used this NRF2 cancer signature to infer NRF2 activity across 9000 tumors and found that high NRF2 activity is associated with decreased survival in many cancer types. Additionally, network-based screening for drivers of this universal NRF2 cancer signature has identified several novel genetic modifiers of NRF2 activity.

Universal Majorana thermoelectric noise

Thermoelectric phenomena resulting from an interplay between particle flows induced by electric fields and temperature inhomogeneities are extremely insightful as a tool providing substantial knowledge about the microscopic structure of a given system. Tuning, e.g., parameters of a nanoscopic system coupled via tunneling mechanisms to two contacts one may achieve various situations where the electric current induced by an external bias voltage competes with the electric current excited by the temperature difference of the two contacts. Even more exciting physics emerges when the system's electronic degrees freedom split to form Majorana fermions which make the thermoelectric dynamics universal. Here we propose revealing this unique universal signatures of Majorana fermions in strongly nonequilibrium quantum dots via noise of the thermoelectric transport beyond linear response. It is demonstrated that whereas mean thermoelectric quantities are only universal at large bias voltages, the noise of the electric current excited by an external bias voltage and the temperature difference of the contacts is universal at any bias voltage. We provide truly universal, i.e. independent of the system's parameters, thermoelectric ratios between nonlinear response coefficients of the noise and mean current at large bias voltages where experiments may easily be performed to uniquely detect these truly universal Majorana thermoelectric signatures.

Evidence of universal inverse-third power law for the shielding-induced fractional decrease in apex field enhancement factor at large spacings: a response via accurate Laplace-type calculations

Numerical simulations are important when assessing the many characteristics of field emission related phenomena. In small simulation domains, the electrostatic effect from the boundaries is known to influence the calculated apex field enhancement factor (FEF) of the emitter, but no established dependence has been reported at present. In this work, we report the dependence of the lateral size, L, and the height, H, of the simulation domain on the apex-FEF of a single conducting ellipsoidal emitter. Firstly, we analyze the error, ε, in the calculation of the apex-FEF as a function of H and L. Importantly, our results show that the effects of H and L on ε are scale invariant, allowing one to predict ε for ratios L/h and H/h, where h is the height of the emitter. Next, we analyze the fractional change of the apex-FEF, δ, from a single emitter, , and a pair, . We show that small relative errors in (i.e. ), due to the finite domain size, are sufficient to alter the functional dependence , where c is the distance from the emitters in the pair. We show that obeys a recently proposed power law decay (Forbes 2016 J. Appl. Phys. 120 054302), at sufficiently large distances in the limit of infinite domain size (, say), which is not observed when using a long time established exponential decay (Bonard et al 2001 Adv. Mater. 13 184) or a more sophisticated fitting formula proposed recently by Harris et al (2015 AIP Adv. 5 087182). We show that the inverse-third power law functional dependence is respected for various systems like infinity arrays and small clusters of emitters with different shapes. Thus, , with m = 3, is suggested to be a universal signature of the charge-blunting effect in small clusters or arrays, at sufficient large distances between emitters with any shape. These results improve the physical understanding of the field electron emission theory to accurately characterize emitters in small clusters or arrays.

Ultrafast mid-infrared spectrochronography of dispersion near molecular absorption bands.

Quantitative characterization of dispersion near molecular resonances is difficult both conceptually and technically, as it requires systematic measurements of rapidly varying dispersion profiles across the edges of molecular absorption bands. Here, we show that this challenge can be confronted with an ultrafast spectrochronography technique that combines time-resolved four-wave mixing and cross-correlation frequency-resolved optical gating. We demonstrate that, with the spectrum of an ultrashort mid-infrared laser probe stretching across the edge of a molecular absorption band, the Wigner chronocyclic maps of such a probe reveal universal signatures of anomalous dispersion and help quantify such dispersion anomalies.

Gene expression profile analysis of the progression of carotid atherosclerotic plaques.

The present study aimed to examine the universal gene expression signature and the underlying molecular mechanisms involved in the progression of carotid atherosclerotic plaques. The gene expression dataset, GSE28829, containing 13 early and 16 advanced carotid atherosclerotic plaques was selected for analysis. The differentially expressed genes (DEGs) were identified and analyzed using bioinformatics analyses, including cluster analysis, Gene Ontology (GO) and pathway enrichment analyses. Finally, a protein-protein interaction (PPI) was constructed and analyzed. A total of 515 downregulated and 243 downregulated DEGs were identified. The cluster analysis revealed two separate two groups. In addition, the GO terms enriched by the upregulated DEGs were associated with immune response, and the downregulated DEGs were associated with cell adhesion. The upregulated DEGs were enriched in pathways associated with signaling in the immune system, and the downregulated DEGs were enriched in pathways associated with muscle contraction. In the PPI network analysis, ITGAM and ACTN2 had the highest decrees of connectivity in the upregulated and downregulated DEGs, respectively. These findings suggested that deregulation of the immune system and smooth muscle cell cytoskeleton accelerates the progression of carotid atherosclerotic plaques. The DEGs identified may offer potential in the prevention and treatment of atherosclerosis in the carotid artery.

CD137+CD154- Expression As a Regulatory T Cell (Treg)-Specific Activation Signature for Identification and Sorting of Stable Human Tregs from In Vitro Expansion Cultures.

Regulatory T cells (Tregs) are an attractive therapeutic tool for several different immune pathologies. Therapeutic Treg application often requires prolonged in vitro culture to generate sufficient Treg numbers or to optimize their functionality, e.g., via genetic engineering of their antigen receptors. However, purity of clinical Treg expansion cultures is highly variable, and currently, it is impossible to identify and separate stable Tregs from contaminating effector T cells, either ex vivo or after prior expansion. This represents a major obstacle for quality assurance of expanded Tregs and raises significant safety concerns. Here, we describe a Treg activation signature that allows identification and sorting of epigenetically imprinted Tregs even after prolonged in vitro culture. We show that short-term reactivation resulted in expression of CD137 but not CD154 on stable FoxP3+ Tregs that displayed a demethylated Treg-specific demethylated region, high suppressive potential, and lack of inflammatory cytokine expression. We also applied this Treg activation signature for rapid testing of chimeric antigen receptor functionality in human Tregs and identified major differences in the signaling requirements regarding CD137 versus CD28 costimulation. Taken together, CD137+CD154− expression emerges as a universal Treg activation signature ex vivo and upon in vitro expansion allowing the identification and isolation of epigenetically stable antigen-activated Tregs and providing a means for their rapid functional testing in vitro.