bluuebunny/crossref_metadata_2025 huggingface dataset:
Hollow Silica‐Based Porous Liquids Functionalized Mixed Matrix Membranes for CO2 Capture
Authors: Liu Shuo , Meng Long , Fan Jinwen
Published: May 2021

Porous liquids (PLs) are a newly emerging type of porous materials with empty cavities and tailed functionalities, demonstrating great potential in gas capture. However, PLs used as fillers of mixed matrix membranes (MMMs) are seldom reported till now. Herein, MMMs for CO2 selective separation were prepared by incorporating hollow silica PLs into Pebax‐1657 matrix. As expected, the liquid‐like property of PLs renders excellent filler dispersion. Besides, the hollow cavities construct fast permeation diffusion channels, reducing trans‐membrane permeation resistance. More importantly, CO2‐philic moieties of PLs lead to superior CO2 selective permeation. Therefore, the as‐prepared MMM exhibited a CO2 permeability up to 229.5 Barrer with a CO2/N2 selectivity up to 71.7 (241.9 % and 90.2 % increment than those of pure Pebex‐1657 membrane, respectively), surpassing the 2008 Robeson upper bound. Finally, molecular simulation was applied to verify the improved interaction between gas molecules and membrane by analyzing interaction parameters. Our work underlines the feasibility and importance of porous liquids to design advanced fillers in MMMs, which makes great promise for CO2 capture.
Effects of Multiple OH/SH Substitution on the H‐Bonding/Stability versus Aromaticity of Benzene Rings: From Computational Insights
Authors: Pandey Sarvesh Kumar , Arunan Elangannan
Published: May 2021

Properties of intramolecular H‐bond (IHB) for a chemical system can affect the changes in geometrical/electronic features in the vicinity of the bridge. Substitution of an atom (H) in benzene with OH/SH groups forming IHB has little effect on its aromaticity. This report is devoted to the depiction of the effect of OH/SH substituent on stability/aromaticity of multi‐substituted benzene ringsviaIHB formation. The computational studies on the stability/aromaticity in the homo (OH/SH) and hetero (OH and SH) substituted form of the benzene systems have been investigated using B3LYP/aug‐cc‐pVDZ and MP2/aug‐cc‐pVDZ approaches with the aid of aromaticity indices (AIs) descriptors (NICS, HOMA, AIBIC, and PDI) and IHB/stability diagnostics; relative energy, QTAIM based interaction energy acquired from the potential energy density and electron density, HBSBIC, and HOMO‐LUMO gap including NCI plots. The IHBs formed by different OH/SH substituents have a vital role as an aromaticity modulator and deploying the above‐said tools, it turns out that the cyclic 4n+2 π‐electrons delocalization is weakened/strengthened depending on the number and types of OH/SH substituents forming the IHBs. Here, all the AIs vary in a small amount and indicative of the modulator of the π‐electron structure to the substituent effectviaIHB formation. As in practical applications, the diagnostics based on different criteria do not speak with the same voice, hence interestingly, in many cases, the changes in AIs notably correlate with their stability.
Associations of cannabis use, opioid use, and their combination with serious psychological distress among Ontario adults
Authors: Nigatu Yeshambel T. , Elton‐Marshall Tara , Mann Robert E. , Hamilton Hayley A.
Published: May 2021

Considering the widespread use of cannabis and opioids, examining the use of cannabis, opioids and their combination with serious psychological distress (SPD) is important. A total of N = 12,358 adults participating in the Monitor surveillance study between 2014 and 2019 were included. Cannabis and opioid use reflected any use of the substances in the past 12 months. SPD was defined as having a score of 13 or more on the Kessler‐6 questionnaire, a 6‐item scale that includes feeling nervous, hopeless, restless or fidgety, sad or depressed. Odds ratios (ORs) were estimated from logistic regression models accounting for complex survey design and sociodemographic factors. Overall, 12.8% of the sample reported cannabis use only, 18% reported opioid use only, and 4.9% reported both cannabis and opioid use. Use of both cannabis and opioids was significantly associated with SPD in both women (OR = 4.24; 95% CI, 2.34 to 7.69), and in men (OR = 2.99; 95% CI, 1.56 to 5.73) compared to use of neither. The joint association of cannabis and opioids with SPD was additive. Addressing those who use both cannabis and opioids may help reduce the burden of SPD among adults in Ontario.
Dual Network Sponge for Compressible Lithium‐Ion Batteries
Authors: Wang Zhipeng , Wang Yunsong , Chen Yijun , Wu Huaisheng , Wu Yizeng , Zhao Xuewei , Han Ray P. S. , Cao Anyuan
Published: May 2021

Compressible energy devices have received increasing attention with the rapid development of flexible electronics and wearable devices due to their size adaptability and functional stability. However, it is hard to simultaneously achieve satisfactory energy density and mechanical stability for electrodes. Here an open‐porous dual network sponge (DNS) with two networks of highly conductive carbon nanotubes and Li+‐intercalating TiO2‐B nanowires is synthesized and employed as compressible lithium ion battery electrodes. All 1D components inside the DNS mutually penetrate with each other to form two physically distinct but functionally coupling networks, endowing DNS excellent compressibility and stability. A prototype compressible lithium‐ion battery (C‐LIB) is also demonstrated, in which the DNS exhibits a specific capacity of >238 mAh g−1 under static 50% strain, and further in situ measurements show that under 1000 times of cyclic strains, DNS can charge and discharge normally maintaining a high capacity of 240 mAh g−1 and exhibits robustness to fast strain rates up to 500% min−1. The dual network structure can be extended to design high‐performance compliant electrodes that are promising to serve in future compressible and deformable electronics and energy systems.
Holographic complexity of rotating black holes
Authors: Al Balushi Abdulrahim , Hennigar Robie A. , Kunduri Hari K. , Mann Robert B.
Published: May 2021

Abstract

Within the framework of the “complexity equals action” and “complexity equals volume” conjectures, we study the properties of holographic complexity for rotating black holes. We focus on a class of odd-dimensional equal-spinning black holes for which considerable simplification occurs. We study the complexity of formation, uncovering a direct connection between complexity of formation and thermodynamic volume for large black holes. We consider also the growth-rate of complexity, finding that at late-times the rate of growth approaches a constant, but that Lloyd’s bound is generically violated.
Double-Janus linear sigma models and generalized reciprocity for Gauss sums
Authors: Ganor Ori J. , Sun Hao-Yu , Torres-Chicon Nesty R.
Published: May 2021

Abstract

We study the supersymmetric partition function of a 2d linear σ-model whose target space is a torus with a complex structure that varies along one worldsheet direction and a Kähler modulus that varies along the other. This setup is inspired by the dimensional reduction of a Janus configuration of 4d $$ \mathcal{N} $$
N
= 4 U(1) Super-Yang-Mills theory compactified on a mapping torus (T2 fibered over S1) times a circle with an SL(2, ℤ) duality wall inserted on S1, but our setup has minimal supersymmetry. The partition function depends on two independent elements of SL(2, ℤ), one describing the duality twist, and the other describing the geometry of the mapping torus. It is topological and can be written as a multivariate quadratic Gauss sum. By calculating the partition function in two different ways, we obtain identities relating different quadratic Gauss sums, generalizing the Landsberg-Schaar relation. These identities are a subset of a collection of identities discovered by F. Deloup. Each identity contains a phase which is an eighth root of unity, and we show how it arises as a Berry phase in the supersymmetric Janus-like configuration. Supersymmetry requires the complex structure to vary along a semicircle in the upper half-plane, as shown by Gaiotto and Witten in a related context, and that semicircle plays an important role in reproducing the correct Berry phase.
Summing over geometries in string theory
Authors: Eberhardt Lorenz
Published: May 2021

Abstract

We examine the question how string theory achieves a sum over bulk geometries with fixed asymptotic boundary conditions. We discuss this problem with the help of the tensionless string on $$ {\mathrm{\mathcal{M}}}_3\times {\mathrm{S}}^3\times {\mathbbm{T}}^4 $$

ℳ
3

×

S
3

×

T
4

(with one unit of NS-NS flux) that was recently understood to be dual to the symmetric orbifold SymN ($$ {\mathbbm{T}}^4 $$

T
4

). We strengthen the analysis of [1] and show that the perturbative string partition function around a fixed bulk background already includes a sum over semi-classical geometries and large stringy corrections can be interpreted as various semi-classical geometries. We argue in particular that the string partition function on a Euclidean wormhole geometry factorizes completely into factors associated to the two boundaries of spacetime. Central to this is the remarkable property of the moduli space integral of string theory to localize on covering spaces of the conformal boundary of ℳ3. We also emphasize the fact that string perturbation theory computes the grand canonical partition function of the family of theories ⊕N SymN ($$ {\mathbbm{T}}^4 $$

T
4

). The boundary partition function is naturally expressed as a sum over winding worldsheets, each of which we interpret as a ‘stringy geometry’. We argue that the semi-classical bulk geometry can be understood as a condensate of such stringy geometries. We also briefly discuss the effect of ensemble averaging over the Narain moduli space of $$ {\mathbbm{T}}^4 $$

T
4

and of deforming away from the orbifold by the marginal deformation.
A natural mechanism for approximate Higgs alignment in the 2HDM
Authors: Draper Patrick , Ekstedt Andreas , Haber Howard E.
Published: May 2021

Abstract

The 2HDM possesses a neutral scalar interaction eigenstate whose tree-level properties coincide with the Standard Model (SM) Higgs boson. In light of the LHC Higgs data which suggests that the observed Higgs boson is SM-like, it follows that the mixing of the SM Higgs interaction eigenstate with the other neutral scalar interaction eigenstates of the 2HDM should be suppressed, corresponding to the so-called Higgs alignment limit. The exact Higgs alignment limit can arise naturally due to a global symmetry of the scalar potential. If this symmetry is softly broken, then the Higgs alignment limit becomes approximate (although still potentially consistent with the current LHC Higgs data). In this paper, we obtain the approximate Higgs alignment suggested by the LHC Higgs data as a consequence of a softly broken global symmetry of the Higgs Lagrangian. However, this can only be accomplished if the Yukawa sector of the theory is extended. We propose an extended 2HDM with vector-like top quark partners, where explicit mass terms in the top sector provide the source of the soft symmetry breaking of a generalized CP symmetry. In this way, we can realize approximate Higgs alignment without a significant fine-tuning of the model parameters. We then explore the implications of the current LHC bounds on vector-like top quark partners for the success of our proposed scenario.
Dispersive CFT sum rules
Authors: Caron-Huot Simon , Mazáč Dalimil , Rastelli Leonardo , Simmons-Duffin David
Published: May 2021

Abstract

We give a unified treatment of dispersive sum rules for four-point correlators in conformal field theory. We call a sum rule “dispersive” if it has double zeros at all double-twist operators above a fixed twist gap. Dispersive sum rules have their conceptual origin in Lorentzian kinematics and absorptive physics (the notion of double discontinuity). They have been discussed using three seemingly different methods: analytic functionals dual to double-twist operators, dispersion relations in position space, and dispersion relations in Mellin space. We show that these three approaches can be mapped into one another and lead to completely equivalent sum rules. A central idea of our discussion is a fully nonperturbative expansion of the correlator as a sum over Polyakov-Regge blocks. Unlike the usual OPE sum, the Polyakov-Regge expansion utilizes the data of two separate channels, while having (term by term) good Regge behavior in the third channel. We construct sum rules which are non-negative above the double-twist gap; they have the physical interpretation of a subtracted version of “superconvergence” sum rules. We expect dispersive sum rules to be a very useful tool to study expansions around mean-field theory, and to constrain the low-energy description of holographic CFTs with a large gap. We give examples of the first kind of applications, notably we exhibit a candidate extremal functional for the spin-two gap problem.
All-order quartic couplings in highly symmetric D-brane-anti-D-brane systems
Authors: Hatefi Ehsan , Sundell Per
Published: May 2021

Abstract

We compute six-point string amplitudes for the scattering of one closed string Ramond-Ramond state, two tachyons and two gauge fields in the worldvolume of D-brane-anti-D-brane systems in the Type II superstring theories. From the resulting S-matrix elements, we read off the precise form of the couplings, including their exact numerical coefficients, of two tachyons and two gauge fields in the corresponding highly symmetric effective field eheory (EFT) Lagrangian in the worldvolume of D-brane-Anti-D-brane to all orders in α′, which modify and complete previous proposals. We verify that the EFT reproduces the infinite collection of stringy gauge field singularities in dual channels. Inspired by interesting similarities between the all-order highly symmetric EFTs and holographic duals of Vasiliev’s higher spin gravities à là Nilsson and Vasiliev, we make a proposal for tensionless limits of D-brane-anti-D-brane systems.
Arginine-dependent immune responses
Authors: Martí i Líndez Adrià-Arnau , Reith Walter
Published: May 2021

A growing body of evidence indicates that, over the course of evolution of the immune system, arginine has been selected as a node for the regulation of immune responses. An appropriate supply of arginine has long been associated with the improvement of immune responses. In addition to being a building block for protein synthesis, arginine serves as a substrate for distinct metabolic pathways that profoundly affect immune cell biology; especially macrophage, dendritic cell and T cell immunobiology. Arginine availability, synthesis, and catabolism are highly interrelated aspects of immune responses and their fine-tuning can dictate divergent pro-inflammatory or anti-inflammatory immune outcomes. Here, we review the organismal pathways of arginine metabolism in humans and rodents, as essential modulators of the availability of this semi-essential amino acid for immune cells. We subsequently review well-established and novel findings on the functional impact of arginine biosynthetic and catabolic pathways on the main immune cell lineages. Finally, as arginine has emerged as a molecule impacting on a plethora of immune functions, we integrate key notions on how the disruption or perversion of arginine metabolism is implicated in pathologies ranging from infectious diseases to autoimmunity and cancer.
Is it the coracobrachialis superior muscle, or is it an unidentified rare variant of coracobrachialis muscle?
Authors: Olewnik Łukasz , Zielinska Nicol , Gołek Łukasz , Aragonés Paloma , Sanudo Jose Ramon
Published: May 2021

The coracobrachialis muscle (CBM) originates from the apex of the coracoid process, in common with the short head of the biceps brachii muscle, and from the intermuscular septum. The CBM demonstrates variability in both the proximal and distal attachment, with some extremely rare varieties, such as the coracobrachialis superior, coracobrachialis longus and coracocapsularis muscle. This case report describes an extremely rare variant of the coracobrachialis superior muscle, or a very rare variant of the CBM. Our findings highlight the importance of muscle variants in the shoulder region, especially the coracoid region, and are significant for radiologists, anatomists, physiotherapists and surgeons specializing in the shoulder joint.
Testing for equality of distributions using the concept of (niche) overlap
Authors: Parkinson-Schwarz Judith H. , Bathke Arne C.
Published: May 2021

In this paper, we propose a new non-parametric test for equality of distributions. The test is based on the recently introduced measure of (niche) overlap and its rank-based estimator. As the estimator makes only one basic assumption on the underlying distribution, namely continuity, the test is universal applicable in contrast to many tests that are restricted to only specific scenarios. By construction, the new test is capable of detecting differences in location and scale. It thus complements the large class of rank-based tests that are constructed based on the non-parametric relative effect. In simulations this new test procedure obtained higher power and lower type I error compared to two common tests in several settings. The new procedure shows overall good performance. Together with its simplicity, this test can be used broadly.
In Vitro 1H NMR Metabolic Profiles of Liver, Brain, and Serum in Rats After Chronic Consumption of Alcohol
Authors: Pravdivtseva Mariya S. , Shevelev Oleg B. , Yanshole Vadim V. , Moshkin Mikhail P. , Koptyug Igor V. , Akulov Andrey E.
Published: May 2021

The impact of alcohol on the body can be investigated with NMR spectroscopy in vitro, which can detect a wide range of metabolites but preparing samples includes tissue biopsy. Blood sampling is less invasive, but blood metabolic content might not reflect the changes occurring in other tissues. Thus, this study aimed to investigate the liver, brain, and serum metabolism and evaluate the link between tissues and serum metabolic content. Two experimental groups with ten outbred rats each were provided intragastrically with water (control group) and 50% ethanol solution (alcohol group) for 28 days. 1H NMR spectroscopy in vitro was performed on the brain cortex, liver, and serum samples. Student’s t test with Holm–Bonferroni correction was used to investigate significant differences between groups. Partial least-squares discriminant analysis (PLS-DA) and two-way ANOVA were performed to compare liver and serum, brain and serum. In all, 38, 37, and 21 metabolites were identified in the liver, brain, and serum samples, respectively. Significant differences for three metabolites were found in the liver (alanine, proline, and glutathione, p < 0.002) and four in serum (lactate, betaine, acetate, and formic acid, p < 0.002) were detected between the control and alcohol groups. The contents of glucose, betaine, and isoleucine were correlated (r > 0.65) between serum and liver samples. PLS-DA determined separation between all tissues (p < 0.001) and between control and alcohol groups only for liver and serum (p < 0.001). Alcohol had a more substantial effect on liver and serum metabolism than on the brain.
The Saami and the Karen — common experience and differences: a comparative perspective
Authors: Szpak Agnieszka , Ochwat Maria
Published: May 2021

This paper offers a comparative perspective on a specific issue of the indigenous peoples of the Saami and the Karen. The groups being compared are from Europe and Asia, selected on the basis of their particular circumstances of living in more than one State. However, while the Saami are a relatively well-treated people that enjoy a form of cultural autonomy; the Karen are in a far worse situation with regard to their legal position as well as actual living conditions. The authors examine the cultural, political, and legal aspects of the Saami and the Karen situations and compare their common experience and aspirations. The article attempts to answer the question as to what the similarities and differences between the two indigenous peoples are and what lessons can be learned by those peoples that may be helpful in realizing their aspirations.
The Fundamental Group of a Noncommutative Space
Authors: van Suijlekom Walter D. , Winkel Jeroen
Published: May 2021

We introduce and analyse a general notion of fundamental group for noncommutative spaces, described by differential graded algebras. For this we consider connections on finitely generated projective bimodules over differential graded algebras and show that the category of flat connections on such modules forms a Tannakian category. As such this category can be realised as the category of representations of an affine group scheme G, which in the classical case is (the pro-algebraic completion of) the usual fundamental group. This motivates us to define G to be the fundamental group of the noncommutative space under consideration. The needed assumptions on the differential graded algebra are rather mild and completely natural in the context of noncommutative differential geometry. We establish the appropriate functorial properties, homotopy and Morita invariance of this fundamental group. As an example we find that the fundamental group of the noncommutative torus can be described as the algebraic hull of the topological group $(\mathbb Z+\theta \mathbb Z)^{2}$

(
ℤ
+
𝜃
ℤ
)

2

.
The Limits of Computation
Authors: Powell Andrew
Published: May 2021

This article provides a survey of key papers that characterise computable functions, but also provides some novel insights as follows. It is argued that the power of algorithms is at least as strong as functions that can be proved to be totally computable in type-theoretic translations of subsystems of second-order Zermelo Fraenkel set theory. Moreover, it is claimed that typed systems of the lambda calculus give rise naturally to a functional interpretation of rich systems of types and to a hierarchy of ordinal recursive functionals of arbitrary type that can be reduced by substitution to natural number functions.
Polycyclic aromatic hydrocarbons (PAHs) in soils of an industrial area in semi-arid Uzbekistan: spatial distribution, relationship with trace metals and risk assessment
Authors: Bandowe Benjamin A. Musa , Shukurov Nosir , Leimer Sophia , Kersten Michael , Steinberger Yosef , Wilcke Wolfgang
Published: May 2021

The concentrations, composition patterns, transport and fate of PAHs in semi-arid and arid soils such as in Central Asia are not well known. Such knowledge is required to manage the risk posed by these toxic chemicals to humans and ecosystems in these regions. To fill this knowledge gap, we determined the concentrations of 21 parent PAHs, 4,5-methylenephenanthrene, 6 alkylated PAHs, and biphenyl in soils from 11 sampling locations (0–10, 10–20 cm soil depths) along a 20-km transect downwind from the Almalyk metal mining and metallurgical industrial complex (Almalyk MMC), Uzbekistan. The concentrations of Σ29 PAHs and Σ16 US-EPA PAHs were 41–2670 ng g−1 and 29–1940 ng g−1, respectively. The highest concentration of Σ29 PAHs occurred in the immediate vicinity of the copper smelting factory of the Almalyk MMC. The concentrations in topsoil decreased substantially to a value of ≤ 200 ng g−1 (considered as background concentration) at ≥ 2 km away from the factory. Low molecular weight PAHs dominated the PAH mixtures at less contaminated sites and high molecular weight PAHs at the most contaminated site. The concentration of Σ16 US-EPA PAHs did not exceed the precautionary values set by the soil quality guidelines of, e.g., Switzerland and Germany. Similarly, the benzo[a]pyrene equivalent concentration in soils near the Almalyk MMC did not exceed the value set by the Canadian guidelines for the protection of humans from carcinogenic PAHs in soils. Consequently, the cancer risk due to exposure to PAHs in these soils can be considered as low.
Nāgārjunian-Yogācārian Modal Logic versus Aristotelian Modal Logic
Authors: Schumann Andrew
Published: May 2021

There are two different modal logics: the logic T assuming contingency and the logic K = assuming logical determinism. In the paper, I show that the Aristotelian treatise On Interpretation (Περί ερμηνείας, De Interpretatione) has introduced some modal-logical relationships which correspond to T. In this logic, it is supposed that there are contingent events. The Nāgārjunian treatise Īśvara-kartṛtva-nirākṛtiḥ-viṣṇoḥ-ekakartṛtva-nirākaraṇa has introduced some modal-logical relationships which correspond to K =. In this logic, it is supposed that there is a logical determinism: each event happens necessarily (siddha) or it does not happen necessarily (asiddha). The Nāgārjunian approach was inherited by the Yogācārins who developed, first, the doctrine of causality of all real entities (arthakriyātva) and, second, the doctrine of momentariness of all real entities (kṣaṇikavāda). Both doctrines were a philosophical ground of the Yogācārins for the logical determinism. Hence, Aristotle implicitly used the logic T in his modal reasoning. The Madhyamaka and Yogācāra schools implicitly used the logic K = in their modal reasoning.
Steady-State Serum IgG Trough Levels Are Adequate for Pharmacokinetic Assessment in Patients with Immunodeficiencies Receiving Subcutaneous Immune Globulin
Authors: Li Zhaoyang , McCoy Barbara , Engl Werner , Yel Leman
Published: May 2021

Patients with primary immunodeficiency diseases often require lifelong immunoglobulin (IG) therapy. Most clinical trials investigating IG therapies characterize serum immunoglobulin G (IgG) pharmacokinetic (PK) profiles by serially assessing serum IgG levels. This retrospective analysis evaluated whether steady-state serum IgG trough level measurement alone is adequate for PK assessment. Based on individual patient serum IgG trough levels from two pivotal trials (phase 2/3 European [NCT01412385] and North American [NCT01218438]) of weekly 20% subcutaneous IG (SCIG; Cuvitru, Ig20Gly), trough level-predicted IgG AUC (AUCτ,tp) were calculated and compared with the reported AUC calculated from serum IgG concentration-time profiles (AUCτ). In both studies, mean AUCτ,tpvalues for Ig20Gly were essentially equivalent to AUCτwith point estimates of geometric mean ratio (GMR) of AUCτ,tp/AUCτnear 1.0 and 90% CIs within 0.80–1.25. In contrast, for IVIG, 10%, mean AUCτ,tpvalues were lower than AUCτby >20%, (GMR [90% CI]: 0.74 [0.70–0.78] and 0.77 [0.73–0.81] for the two studies, respectively). Mean AUCτ,tpvalues calculated for 4 other SCIG products (based on mean IgG trough levels reported in the literature/labels) were also essentially equivalent to the reported AUCτ(differences <10% for all except HyQvia, a facilitated SCIG product), while differences for IVIG products were >20%. In conclusion, steady-state serum IgG levels following weekly SCIG remain stable, allowing for reliable prediction of AUC over the dosing interval using trough IgG levels. These findings indicate that measuring steady-state serum IgG trough levels alone may be adequate for PK assessment of weekly SCIG.
Bioreactance and fourth-generation pulse contour methods in monitoring cardiac index during off-pump coronary artery bypass surgery
Authors: Ylikauma Laura Anneli , Ohtonen Pasi Petteri , Erkinaro Tiina Maria , Vakkala Merja Annika , Liisanantti Janne Henrik , Satta Jari Uolevi , Juvonen Tatu Sakari , Kaakinen Timo Ilari
Published: May 2021

The pulmonary artery catheter (PAC) is considered the gold standard for cardiac index monitoring. Recently new and less invasive methods to assess cardiac performance have been developed. The aim of our study was to assess the reliability of a non-invasive monitor utilizing bioreactance (Starling SV) and a non-calibrated mini-invasive pulse contour device (FloTrac/EV1000, fourth-generation software) compared to bolus thermodilution technique with PAC (TDCO) during off-pump coronary artery bypass surgery (OPCAB). In this prospective study, 579 simultaneous intra- and postoperative cardiac index measurements obtained with Starling SV, FloTrac/EV1000 and TDCO were compared in 20 patients undergoing OPCAB. The agreement of data was investigated by Bland–Altman plots, while trending ability was assessed by four-quadrant plots with error grids. In comparison with TDCO, Starling SV was associated with a bias of 0.13 L min−1 m−2 (95% confidence interval, 95% CI, 0.07 to 0.18), wide limits of agreement (LOA, − 1.23 to 1.51 L min−1 m−2), a percentage error (PE) of 60.7%, and poor trending ability. In comparison with TDCO, FloTrac was associated with a bias of 0.01 L min−1 m−2 (95% CI − 0.05 to 0.06), wide LOA (− 1.27 to 1.29 L min−1 m−2), a PE of 56.8% and poor trending ability. Both Starling SV and fourth-generation FloTrac showed acceptable mean bias but imprecision due to wide LOA and high PE, and poor trending ability. These findings indicate limited reliability in monitoring cardiac index in patients undergoing OPCAB.
Thermodynamic Properties of the Superconducting State in Metallic Hydrogen: Electronic Correlations, Non-conventional Electron-Phonon Couplings and the Anharmonic Effects
Authors: Kostrzewa M. , Durajski A. P. , Kalaga J. K. , Szczȩśniak R.
Published: May 2021

Thermodynamical properties of the superconducting state in metallic hydrogen were determined on the basis of the model of two compressed hydrogen planes. We took into account both the on-site and the inter-site electronic correlations (UandK), as well as the relevant non-conventional electron-phonon coupling functions (gUandgK). We proved, within the Eliashberg formalism, that the maximum value of the critical temperature of transition into the superconducting state is about 200 K for the harmonic approximation, and about 84 K for the Morse anharmonic approximation. Omission of the electronic correlations results in a considerable overstatement of theTCvalue. On the other hand, theTCvalue is remarkably understated if the non-conventional interactions are disregarded. Other thermodynamic quantities, such as the order parameter, the jump in the specific heat value, the thermodynamic critical field, and the upper critical field, take the values for which the non-dimensional ratiosRΔ,RC,RHandRH2do not differ substantially from the predictions of the BCS theory.
Efficacy of Fenfluramine and Norfenfluramine Enantiomers and Various Antiepileptic Drugs in a Zebrafish Model of Dravet Syndrome
Authors: Li Jing , Nelis Maxim , Sourbron Jo , Copmans Daniëlle , Lagae Lieven , Cabooter Deirdre , de Witte Peter A. M.
Published: May 2021

Dravet syndrome (DS) is a rare genetic encephalopathy that is characterized by severe seizures and highly resistant to commonly used antiepileptic drugs (AEDs). In 2020, FDA has approved fenfluramine (FFA) for treatment of seizures associated with DS. However, the clinically used FFA is a racemic mixture (i.e. (±)-FFA), that is substantially metabolized to norfenfluramine (norFFA), and it is presently not known whether the efficacy of FFA is due to a single enantiomer of FFA, or to both, and whether the norFFA enantiomers also contribute significantly. In this study, the antiepileptic activity of enantiomers of FFA (i.e. (+)-FFA and (−)-FFA) and norFFA (i.e. (+)-norFFA and (−)-norFFA) was explored using the zebrafish scn1Lab−/− mutant model of DS. To validate the experimental conditions used, we assessed the activity of various AEDs typically used in the fight against DS, including combination therapy. Overall, our results are highly consistent with the treatment algorithm proposed by the updated current practice in the clinical management of DS. Our results show that (+)-FFA, (−)-FFA and (+)-norFFA displayed significant antiepileptic effects in the preclinical model, and thus can be considered as compounds actively contributing to the clinical efficacy of FFA. In case of (−)-norFFA, the results were less conclusive. We also investigated the uptake kinetics of the enantiomers of FFA and norFFA in larval zebrafish heads. The data show that the total uptake of each compound increased in a time-dependent fashion. A somewhat similar uptake was observed for the (+)-norFFA and (−)-norFFA, implying that the levo/dextrotation of the structure did not dramatically affect the uptake. Significantly, when comparing (+)-FFA with the less lipophilic (+)-norFFA, the data clearly show that the nor-metabolite of FFA is taken up less than the parent compound.
Characterizing Family Contextual Factors and Relationships with Child Behavior and Sleep Across the Buffering Toxic Stress Consortium
Authors: Phu Tiffany , Miles Elly , Dominguez Amy , Hustedt Jason , Watamura Sarah Enos ,   BTS Consortium Principal Investigators
Published: May 2021

The Buffering Toxic Stress (BTS) consortium included six sites in locations that varied widely in racial/ethnic composition and population density. Each site tested a promising parent–child intervention designed to supplement Early Head Start (EHS) services and prevent “toxic stress.” To better understand family risk in a large and diverse EHS sample, studies gathered extensive data on family risk exposure, including demographic risk factors (single mother, unemployed, less than high school education or its equivalent, and neighborhood safety), income-to-needs ratio, household resource constraints, perceptions of economic hardship and pressure, caregiver mental health, and caregiver-reported dysfunctional parent–child interactions. Results presented here for all six sites offer context for the more targeted studies in this special issue. Average levels of family characteristics and child behavior varied by site. We also characterized associations between family characteristics, observer-rated child temperament, and child outcomes (i.e., caregiver-reported child behavior problems and behavioral sleep quality), controlling for child age; these relationships were similar across sites. Demographic risk and caregiver mental health problems were positively associated with child behavior problems, with low income-to-needs ratio and increased financial strain relating to behavioral problems in infancy and toddlerhood. Caregiver mental health problems, financial strain, and social and affect temperament dimensions were related to increased behavioral sleep problems. Dysfunctional parent–child interactions and household resource constraints did not demonstrate statistically significant associations. Findings suggest helpful targets to increase effectiveness of parent–child interventions in early childhood on behavior and sleep outcomes.
Understanding mathematics of Grover’s algorithm
Authors: Szabłowski Paweł J.
Published: May 2021

We analyze the mathematical structure of the classical Grover’s algorithm and put it within the framework of linear algebra over the complex numbers. We also generalize it in the sense, that we are seeking not the one ‘chosen’ element (sometimes called a ‘solution’) of the dataset, but a set ofmsuch ‘chosen’ elements (out of$$n>m)$$n>m). Besides, we do not assume that the so-called initial superposition is uniform. We assume also that we have at our disposal an oracle that ‘marks,’ by a suitable phase change$$\varphi $$φ, all these ‘chosen’ elements. In the first part of the paper, we construct a unique unitary operator that selects all ‘chosen’ elements in one step. The constructed operator is uniquely defined by the numbers$$\varphi $$φand$$\alpha $$αwhich is a certain function of the coefficients of the initial superposition. Moreover, it is in the form of a composition of two so-called reflections. The result is purely theoretical since the phase change required to reach this heavily depends on$$\alpha $$α. In the second part, we construct unitary operators having a form of composition of two or more reflections (generalizing the constructed operator) given the set of orthogonal versors. We find properties of these operations, in particular, their compositions. Further, by considering a fixed, ‘convenient’ phase change$$\varphi ,$$φ,and by sequentially applying the so-constructed operator, we find the number of steps to find these ‘chosen’ elements with great probability. We apply this knowledge to study the generalizations of Grover’s algorithm ($$m=1,\phi =\pi $$m=1,ϕ=π), which are of the form, the found previously, unitary operators.
Evaluating Gaussian process metamodels and sequential designs for noisy level set estimation
Authors: Lyu Xiong , Binois Mickaël , Ludkovski Michael
Published: May 2021

We consider the problem of learning the level set for which a noisy black-box function exceeds a given threshold. To efficiently reconstruct the level set, we investigate Gaussian process (GP) metamodels. Our focus is on strongly stochastic simulators, in particular with heavy-tailed simulation noise and low signal-to-noise ratio. To guard against noise misspecification, we assess the performance of three variants: (i) GPs with Student-tobservations; (ii) Student-tprocesses (TPs); and (iii) classification GPs modeling the sign of the response. In conjunction with these metamodels, we analyze several acquisition functions for guiding the sequential experimental designs, extending existing stepwise uncertainty reduction criteria to the stochastic contour-finding context. This also motivates our development of (approximate) updating formulas to efficiently compute such acquisition functions. Our schemes are benchmarked by using a variety of synthetic experiments in 1–6 dimensions. We also consider an application of level set estimation for determining the optimal exercise policy of Bermudan options in finance.
Performance of deep learning technology for evaluation of positioning quality in periapical radiography of the maxillary canine
Authors: Mori Mizuho , Ariji Yoshiko , Fukuda Motoki , Kitano Tomoya , Funakoshi Takuma , Nishiyama Wataru , Kohinata Kiyomi , Iida Yukihiro , Ariji Eiichiro , Katsumata Akitoshi
Published: May 2021

Objectives

The aim of the present study was to create and test an automatic system for assessing the technical quality of positioning in periapical radiography of the maxillary canines using deep learning classification and segmentation techniques.

Methods

We created and tested two deep learning systems using 500 periapical radiographs (250 each of good- and bad-quality images). We assigned 350, 70, and 80 images as the training, validation, and test datasets, respectively. The learning model of system 1 was created with only the classification process, whereas system 2 consisted of both the segmentation and classification models. In each model, 500 epochs of training were performed using AlexNet and U-net for classification and segmentation, respectively. The segmentation results were evaluated by the intersection over union method, with values of 0.6 or more considered as success. The classification results were compared between the two systems.

Results

The segmentation performance of system 2 was recall, precision, and F measure of 0.937, 0.961, and 0.949, respectively. System 2 showed better classification performance values than those obtained by system 1. The area under the receiver operating characteristic curve values differed significantly between system 1 (0.649) and system 2 (0.927).

Conclusions

The deep learning systems we created appeared to have potential benefits in evaluation of the technical positioning quality of periapical radiographs through the use of segmentation and classification functions.
Nonlocal regularization of an anisotropic critical state model for sand
Authors: Gao Zhiwei , Li Xin , Lu Dechun
Published: May 2021

Many advanced constitutive models which can capture the strain-softening and state-dependent dilatancy response of sand have been developed. These models can give good prediction of the single soil element behaviour under various loading conditions. But the solution will be highly mesh-dependent when they are used in real boundary value problems due to the strain-softening. They can give mesh-dependent strain localization pattern and bearing capacity of foundations on sand. Nonlocal regularization of an anisotropic critical state sand model is presented. The evolution of void ratio which has a significant influence on strain-softening is assumed to depend on the volumetric strain increment of both the local and neighbouring integration points. The regularization method has been implemented using the explicit stress integration method. The nonlocal model has been used in simulating both drained plane strain compression and the response of a strip footing on dry sand. In plane strain compression, mesh-independent results for the force–displacement relationship and shear band thickness can be obtained when the mesh size is smaller than the internal length. The force–displacement relationship of strip footings predicted by the nonlocal model is much less mesh-sensitive than the local model prediction. The strain localization under the strip footing predicted by the nonlocal model is mesh independent. The regularization method is thus proper for application in practical geotechnical engineering problems.
Mechanical Models of Pattern and Form in Biological Tissues: The Role of Stress–Strain Constitutive Equations
Authors: Villa Chiara , Chaplain Mark A. J. , Gerisch Alf , Lorenzi Tommaso
Published: May 2021

Mechanical and mechanochemical models of pattern formation in biological tissues have been used to study a variety of biomedical systems, particularly in developmental biology, and describe the physical interactions between cells and their local surroundings. These models in their original form consist of a balance equation for the cell density, a balance equation for the density of the extracellular matrix (ECM), and a force-balance equation describing the mechanical equilibrium of the cell-ECM system. Under the assumption that the cell-ECM system can be regarded as an isotropic linear viscoelastic material, the force-balance equation is often defined using the Kelvin–Voigt model of linear viscoelasticity to represent the stress–strain relation of the ECM. However, due to the multifaceted bio-physical nature of the ECM constituents, there are rheological aspects that cannot be effectively captured by this model and, therefore, depending on the pattern formation process and the type of biological tissue considered, other constitutive models of linear viscoelasticity may be better suited. In this paper, we systematically assess the pattern formation potential of different stress–strain constitutive equations for the ECM within a mechanical model of pattern formation in biological tissues. The results obtained through linear stability analysis and the dispersion relations derived therefrom support the idea that fluid-like constitutive models, such as the Maxwell model and the Jeffrey model, have a pattern formation potential much higher than solid-like models, such as the Kelvin–Voigt model and the standard linear solid model. This is confirmed by the results of numerical simulations, which demonstrate that, all else being equal, spatial patterns emerge in the case where the Maxwell model is used to represent the stress–strain relation of the ECM, while no patterns are observed when the Kelvin–Voigt model is employed. Our findings suggest that further empirical work is required to acquire detailed quantitative information on the mechanical properties of components of the ECM in different biological tissues in order to furnish mechanical and mechanochemical models of pattern formation with stress–strain constitutive equations for the ECM that provide a more faithful representation of the underlying tissue rheology.
World impact of kernel European Union 9 countries from Google matrix analysis of the world trade network
Authors: Loye Justin , Ermann Leonardo , Shepelyansky Dima L.
Published: May 2021

We use the United Nations COMTRADE database for analysis of the multiproduct world trade network. With this data, considered for years 2012–2018, we determined the world trade impact of the Kernel of EU 9 countries (KEU9), being Austria, Belgium, France, Germany, Italy, Luxembourg, Netherlands, Portugal, Spain, considered as one united country. We apply the advanced Google matrix analysis for investigation of the influence of KEU9 and show that KEU9 takes the top trade network rank positions thus becoming the main player of the world trade being ahead of USA and China. Our network analysis provides additional mathematical grounds in favor of the recent proposal (Saint-Etienne in: Osons l’Europe des Nations. Editions de l’Observatoire/Humensis, Paris, 2018) of KEU9 super-union which is based only on historical, political and economy basis.
Getting High: High Fidelity Simulation of High Granularity Calorimeters with High Speed
Authors: Buhmann Erik , Diefenbacher Sascha , Eren Engin , Gaede Frank , Kasieczka Gregor , Korol Anatolii , Krüger Katja
Published: May 2021

Accurate simulation of physical processes is crucial for the success of modern particle physics. However, simulating the development and interaction of particle showers with calorimeter detectors is a time consuming process and drives the computing needs of large experiments at the LHC and future colliders. Recently, generative machine learning models based on deep neural networks have shown promise in speeding up this task by several orders of magnitude. We investigate the use of a new architecture—the Bounded Information Bottleneck Autoencoder—for modelling electromagnetic showers in the central region of the Silicon-Tungsten calorimeter of the proposed International Large Detector. Combined with a novel second post-processing network, this approach achieves an accurate simulation of differential distributions including for the first time the shape of the minimum-ionizing-particle peak compared to a full Geant4 simulation for a high-granularity calorimeter with 27k simulated channels. The results are validated by comparing to established architectures. Our results further strengthen the case of using generative networks for fast simulation and demonstrate that physically relevant differential distributions can be described with high accuracy.
Reinforcement learning versus swarm intelligence for autonomous multi-HAPS coordination
Authors: Anicho Ogbonnaya , Charlesworth Philip B. , Baicher Gurvinder S. , Nagar Atulya K.
Published: May 2021

This work analyses the performance of Reinforcement Learning (RL) versus Swarm Intelligence (SI) for coordinating multiple unmanned High Altitude Platform Stations (HAPS) for communications area coverage. It builds upon previous work which looked at various elements of both algorithms. The main aim of this paper is to address the continuous state-space challenge within this work by using partitioning to manage the high dimensionality problem. This enabled comparing the performance of the classical cases of both RL and SI establishing a baseline for future comparisons of improved versions. From previous work, SI was observed to perform better across various key performance indicators. However, after tuning parameters and empirically choosing suitable partitioning ratio for the RL state space, it was observed that the SI algorithm still maintained superior coordination capability by achieving higher mean overall user coverage (about 20% better than the RL algorithm), in addition to faster convergence rates. Though the RL technique showed better average peak user coverage, the unpredictable coverage dip was a key weakness, making SI a more suitable algorithm within the context of this work.