bluuebunny/crossref_metadata_2025 huggingface dataset:
Recent Advances in Functionalization of Pyrroles and their Translational Potential
Authors: Hunjan Mandeep Kaur , Panday Surabhi , Gupta Anjali , Bhaumik Jayeeta , Das Parthasarathi , Laha Joydev K.
Published: March 2021

Among the known aromatic nitrogen heterocycles, pyrrole represents a privileged aromatic heterocycle ranging its occurrence in the key component of “pigments of life” to biologically active natural products to active pharmaceuticals. Pyrrole being an electron‐rich heteroaromatic compound, its predominant functionalization is legendary to aromatic electrophilic substitution reactions. Although a few excellent reviews on the functionalization of pyrroles including the reports by Baltazzi in 1963, Casiraghi and Rassu in 1995, and Banwell in 2006 are available, they are fragmentary and over fifteen years old, and do not cover the modern aspects of catalysis. A review covering a comprehensive package of direct functionalization on pyrroles via catalytic and non‐catalytic methods including their translational potential is described. Subsequent to statutory yet concise introduction, the classical functionalization on pyrroles using Lewis acids largely following an ionic mechanism is discussed. The subsequent discussion follows the various metal‐catalyzed C−H functionalization on pyrroles, which are otherwise difficult to implement by Lewis acids. A major emphasize is given on the radical based pyrrole functionalization under metal‐free oxidative conditions, which is otherwise poorly highlighted in the literature. Towards the end, the current development of pyrrole functionalization under photocatalyzed and electrochemical conditions is appended. Only a selected examples of substrates and important mechanisms are discussed for different methods highlighting their scopes and limitations. The aromatic nucleophillic substitution on pyrroles (being an electron‐rich heterocycle) happened to be the subject of recent investigations, which has also been covered accentuating their underlying conceptual development. Despite great achievements over the past several years in these areas, many challenges and problems are yet to be solved, which are all discussed in summary and outlook.
Mechanisms beyond energetics revealed by multiscale kinetic modeling of2D‐material growth and nanocatalysis
Authors: Jiang Huijun , Hou Zhonghuai
Published: March 2021

Entanglement of spatial and/or temporal scales proposes great challenges to unravel mechanisms of complex chemical systems for their rational design. Multiscale modeling and calculations combining theoretical methods and algorithms at different scales provide powerful tools to address such problems. It has been conventionally known that energetics such as the reaction barrier plays an essential role in complex systems involving chemical reactions, in this review, we focus on recent progress of mechanisms beyond energetics revealed by multiscale kinetic modeling to emphasize the variety of underlying mechanism for such systems, and highlights the importance of kinetics in multiscale modeling and calculations for practical applications. Several interesting mechanisms as well as the corresponding concepts of multiscale kinetic modeling are described in detail, ranging from effects of geometry, micro‐orientation, or reactant flux on 2D material epitaxial growth, to diffusion, directional mass transfer, or confinement enhanced electrocatalysis on nanocatalysts.

This article is categorized under:

Theoretical and Physical Chemistry > Reaction Dynamics and Kinetics
Adaptive evolution of engineered yeast for squalene production improvement and its genome‐wide analysis
Authors: Paramasivan Kalaivani , A Aneesha , Gupta Nabarupa , Mutturi Sarma
Published: March 2021

In the present study, the adaptive evolution of a metabolically engineered Saccharomyces cerevisiae strain in the presence of an enzyme inhibitor terbinafine for enhanced squalene accumulation via serial transfer leads to the development of robust strains. After adaptation for nearly 1500 h, a strain with higher squalene production efficiency was identified at a specific growth rate of 0.28 h−1 with a final squalene titer of 193 mg/L, which is 16.5‐fold higher than the BY4741 and 3‐fold higher over the metabolically engineered SK22 strain. Whole‐genome sequencing comparison between the reference strain and the evolved variant SK23 has led to the identification of 462 single‐nucleotide variants (SNVs) between both strains, with 102 SNVs affecting metabolism‐related genes. It was also established that F420I mutation of ERG1 in S. cerevisiae improves squalene synthesis. Further, the effect of increased squalene on lipid droplet and neutral lipid pattern in the evolved mutant strains was investigated by fluorescent techniques proving that the neutral lipid content and clustering of lipid droplets increase with an increase in squalene.
Complexity growth of operators in the SYK model and in JT gravity
Authors: Jian Shao-Kai , Swingle Brian , Xian Zhuo-Yu
Published: March 2021

Abstract

The concepts of operator size and computational complexity play important roles in the study of quantum chaos and holographic duality because they help characterize the structure of time-evolving Heisenberg operators. It is particularly important to understand how these microscopically defined measures of complexity are related to notions of complexity defined in terms of a dual holographic geometry, such as complexity-volume (CV) duality. Here we study partially entangled thermal states in the Sachdev-Ye-Kitaev (SYK) model and their dual description in terms of operators inserted in the interior of a black hole in Jackiw-Teitelboim (JT) gravity. We compare a microscopic definition of complexity in the SYK model known as K-complexity to calculations using CV duality in JT gravity and find that both quantities show an exponential-to-linear growth behavior. We also calculate the growth of operator size under time evolution and find connections between size and complexity. While the notion of operator size saturates at the scrambling time, our study suggests that complexity, which is well defined in both quantum systems and gravity theories, can serve as a useful measure of operator evolution at both early and late times.
Covariant phase space and soft factorization in non-Abelian gauge theories
Authors: He Temple , Mitra Prahar
Published: March 2021

Abstract

We perform a careful study of the infrared sector of massless non-abelian gauge theories in four-dimensional Minkowski spacetime using the covariant phase space formalism, taking into account the boundary contributions arising from the gauge sector of the theory. Upon quantization, we show that the boundary contributions lead to an infinite degeneracy of the vacua. The Hilbert space of the vacuum sector is not only shown to be remarkably simple, but also universal. We derive a Ward identity that relates the n-point amplitude between two generic in- and out-vacuum states to the one computed in standard QFT. In addition, we demonstrate that the familiar single soft gluon theorem and multiple consecutive soft gluon theorem are consequences of the Ward identity.
Slow scrambling in extremal BTZ and microstate geometries
Authors: Craps Ben , De Clerck Marine , Hacker Philip , Nguyen Kévin , Rabideau Charles
Published: March 2021

Abstract

Out-of-time-order correlators (OTOCs) that capture maximally chaotic properties of a black hole are determined by scattering processes near the horizon. This prompts the question to what extent OTOCs display chaotic behaviour in horizonless microstate geometries. This question is complicated by the fact that Lyapunov growth of OTOCs requires nonzero temperature, whereas constructions of microstate geometries have been mostly restricted to extremal black holes.

In this paper, we compute OTOCs for a class of extremal black holes, namely maximally rotating BTZ black holes, and show that on average they display “slow scrambling”, characterized by cubic (rather than exponential) growth. Superposed on this average power-law growth is a sawtooth pattern, whose steep parts correspond to brief periods of Lyapunov growth associated to the nonzero temperature of the right-moving degrees of freedom in a dual conformal field theory.

Next we study the extent to which these OTOCs are modified in certain “superstrata”, horizonless microstate geometries corresponding to these black holes. Rather than an infinite throat ending on a horizon, these geometries have a very deep but finite throat ending in a cap. We find that the superstrata display the same slow scrambling as maximally rotating BTZ black holes, except that for large enough time intervals the growth of the OTOC is cut off by effects related to the cap region, some of which we evaluate explicitly.
Vector mesons on the wall
Authors: Kitano Ryuichiro , Matsudo Ryutaro
Published: March 2021

Abstract

A domain-wall configuration of theη′meson bounded by a string (called a pancake or a Hall droplet) is recently proposed to describe the baryons with spinNc/2. In order to understand its baryon number as well as the flavor quantum number, we argue that the vector mesons (theρandωmesons) should play an essential role for the consistency of the whole picture. We determine the effective theory of large-NcQCD withNfmassless fermions by taking into account a mixed anomaly involving theθ-periodicity and the global symmetry. The anomaly matching requires the presence of a dynamical domain wall on which a$$ \mathrm{U}{\left({N}_f\right)}_{-{N}_c} $$UNf−NcChern-Simons theory is supported. We consider the boundary conditions that should be imposed on the edge of the domain wall, and conclude that there should be a boundary term that couples the$$ \mathrm{U}{\left({N}_f\right)}_{-{N}_c} $$UNf−Ncgauge field to the vector mesons. We discuss the impact on physics of the chiral phase transition and the relation to the “duality” of QCD.
Virtual corrections to gg → ZH in the high-energy and large-mt limits
Authors: Davies Joshua , Mishima Go , Steinhauser Matthias
Published: March 2021

Abstract

We compute the next-to-leading order virtual corrections to the partonic cross-section of the processgg → ZH, in the high-energy and large-mtlimits. We use Padé approximants to increase the radius of convergence of the high-energy expansion in$$ {m}_t^2/s $$mt2/s,$$ {m}_t^2/t $$mt2/tand$$ {m}_t^2/u $$mt2/uand show that precise results can be obtained down to energies which are fairly close to the top quark pair threshold. We present results both for the form factors and the next-to-leading order virtual cross-section.
Neuroimmunologie von COVID‑19
Authors: Skripuletz Thomas , Möhn Nora , Franke Christiana , Prüß Harald
Published: March 2021

Zahlreiche neuroimmunologische Krankheitsbilder wie Enzephalopathien, Enzephalitiden, Myelitiden oder ADEM (akute disseminierte Enzephalomyelitis) sind nach einer Infektion mit SARS-CoV‑2 („severe acute respiratory syndrome coronavirus 2“) gehäuft aufgetreten, was für einen para- oder postinfektiösen Zusammenhang spricht. Ursächlich ist wahrscheinlich eine virusgetriggerte Überaktivierung des Immunsystems mit Hyperinflammation und Zytokin-Sturm, aber möglicherweise auch die Bildung spezifischer Autoantikörper gegen Gewebe des Zentralnervensystems, die sich vor allem im Liquor schwerkranker COVID-19(„coronavirus disease 2019“)-Patienten finden lassen. Eine direkte Schädigung durch die Invasion von SARS-CoV‑2 ins Gehirn oder Rückenmark scheint keine relevante Rolle zu spielen. Bei Patienten mit Multipler Sklerose, Myasthenie oder anderen neuroimmunologischen Krankheitsbildern wird die Anfälligkeit für eine SARS-CoV-2-Infektion sowie das Risiko eines schweren Verlaufs nicht durch die immunmodulierende Therapie bestimmt, sondern durch bekannte Risikofaktoren wie Alter, Komorbiditäten und den krankheitsbedingten Grad der Behinderung. Immuntherapien sollten bei diesen Patienten daher nicht verschoben oder pausiert werden. Inwieweit neuroimmunologische Mechanismen auch für Langzeitfolgen nach überstandener COVID-19-Erkrankung – wie Fatigue, Gedächtnis‑, Schlaf- oder Angststörungen – verantwortlich sind, werden klinische Verlaufsuntersuchungen u. a. in COVID-19-Registerstudien zeigen.
Quantum Principal Bundles on Projective Bases
Authors: Aschieri Paolo , Fioresi Rita , Latini Emanuele
Published: March 2021

The purpose of this paper is to propose a sheaf theoretic approach to the theory of quantum principal bundles over non affine bases. We study noncommutative principal bundles corresponding to $$G \rightarrow G/P$$

G
→
G
/
P

, where G is a semisimple group and P a parabolic subgroup.
Automatic detection of annual rings and pith location along Norway spruce timber boards using conditional adversarial networks
Authors: Habite Tadios , Abdeljaber Osama , Olsson Anders
Published: March 2021

In the woodworking industry, detection of annual rings and location of pith in relation to timber board cross sections, and how these properties vary in the longitudinal direction of boards, is relevant for many purposes such as assessment of shape stability and prediction of mechanical properties of timber. The current work aims at developing a fast, accurate and operationally simple deep learning-based algorithm for automatic detection of surface growth rings and pith location along knot-free clear wood sections of Norway spruce boards. First, individual surface growth rings that are visible along the four longitudinal sides of the scanned boards are detected using trained conditional generative adversarial networks (cGANs). Then, pith locations are determined, on the basis of the detected growth rings, by using a trained multilayer perceptron (MLP) artificial neural network. The proposed algorithm was solely based on raw images of board surfaces obtained from optical scanning and applied to a total of 104 Norway spruce boards with nominal dimensions of $$45\times 145\times 4500\,\hbox {mm}^{3}$$

45
×
145
×
4500

mm
3

. The results show that optical scanners and the proposed automatic method allow for accurate and fast detection of individual surface growth rings and pith location along boards. For boards with the pith located within the cross section, median errors of 1.4 mm and 2.9 mm, in the x- and y-direction, respectively, were obtained. For a sample of boards with the pith located outside the board cross section in most positions along the board, the median discrepancy between automatically estimated and manually determined pith locations was 3.9 mm and 5.4 mm in the x- and y-direction, respectively.
Phase I study to assess safety, biodistribution and radiation dosimetry for 89Zr-girentuximab in patients with renal cell carcinoma
Authors: Merkx Robin I. J. , Lobeek Daphne , Konijnenberg Mark , Jiménez-Franco Luis David , Kluge Andreas , Oosterwijk Egbert , Mulders Peter F.A. , Rijpkema Mark
Published: March 2021

Purpose

In this phase I study, we evaluated the safety, biodistribution and dosimetry of [89Zr]Zr-DFO-girentuximab (89Zr-girentuximab) PET/CT imaging in patients with suspicion of clear cell renal cell carcinoma (ccRCC).

Methods

Ten eligible patients received an intravenous administration of 37 MBq (± 10%) of 89Zr-girentuximab at mass doses of 5 mg or 10 mg. Safety was evaluated according to the NCI CTCAE (version 4.03). Biodistribution and normal organ dosimetry was performed based on PET/CT images acquired at 0.5, 4, 24, 72 and 168 h post-administration. Additionally, tumour dosimetry was performed in patients with confirmed ccRCC and visible tumour uptake on PET/CT imaging.

Results

89Zr-girentuximab was administered in ten patients as per protocol. No treatment-related adverse events ≥ grade 3 were reported. 89Zr-girentuximab imaging allowed successful differentiation between ccRCC and non-ccRCC lesions in all patients, as confirmed with histological data. Dosimetry analysis using OLINDA/EXM 2.1 showed that the organs receiving the highest doses (mean ± SD) were the liver (1.86 ± 0.40 mGy/MBq), the kidneys (1.50 ± 0.22 mGy/MBq) and the heart wall (1.45 ± 0.19 mGy/MBq), with a mean whole body effective dose of 0.57 ± 0.08 mSv/MBq. Tumour dosimetry was performed in the 6 patients with histologically confirmed ccRCC resulting in a median tumour-absorbed dose of 4.03 mGy/MBq (range 1.90–11.6 mGy/MBq).

Conclusions

This study demonstrates that 89Zr-girentuximab is safe and well tolerated for the administered activities and mass doses and allows quantitative assessment of 89Zr-girentuximab PET/CT imaging in patients with suspicion of ccRCC.

Trial registration

NCT03556046—14th of June, 2018
5-Year health-related quality of life outcome in patients with idiopathic normal pressure hydrocephalus
Authors: Junkkari A. , Sintonen H. , Danner N. , Jyrkkänen H. K. , Rauramaa T. , Luikku A. J. , Koivisto A. M. , Roine R. P. , Viinamäki H. , Soininen H. , Jääskeläinen J. E. , Leinonen V.
Published: March 2021

Background

Health-related quality of life (HRQoL) is severely impaired in persons with idiopathic normal pressure hydrocephalus (iNPH). The HRQoL improves in a number of patients after the placement of a cerebrospinal fluid (CSF) shunt, but long-term follow-up of HRQoL is rare.

Methods

Extended follow-up (60 months) of a prospective cohort study involving 189 patients with iNPH who underwent shunt surgery. Preoperative variables were used to predict favorable HRQoL outcome (improvement or non-deterioration) measured by the 15D instrument 5 years after shunting.

Results

Out of the 189 initially enrolled study participants, 88 had completed 5-year HRQoL follow-up (46%), 64 had died (34%), and 37 (20%) failed to complete the HRQoL follow-up but were alive at the end of the study. After initial post-operative HRQoL improvement, HRQoL deteriorated so that 37/88 participants (42%) had a favorable HRQoL outcome 5 years after shunting. Multivariate binary logistic regression analysis indicated that younger age (adjusted OR 0.86, 95% CI 0.77–0.95;p < 0.005), lower body mass index (adjusted OR 0.87, 95% CI 0.77–0.98;p < 0.05) and better Mini-Mental State Examination performance (adjusted OR 1.16, 95% CI 1.01–1.32;p < 0.05) before surgery predicted favorable 5-year outcome.

Conclusions

This extended follow-up showed that the self-evaluated HRQoL outcome is associated with iNPH patients’ pre-operative cognitive status, overweight and age. The post-operative deterioration may reflect the natural progression of iNPH, but also derive from aging and comorbidities. It indicates a need for long-term follow-up.
Hemodialysis (HD) dose and ultrafiltration rate are associated with survival in pediatric and adolescent patients on chronic HD—a large observational study with follow-up to young adult age
Authors: Gotta Verena , Marsenic Olivera , Atkinson Andrew , Pfister Marc
Published: March 2021

Background

Hemodialysis (HD) dose targets and ultrafiltration rate (UFR) limits for pediatric patients on chronic HD are not known and are derived from adults (spKt/V>1.4 and <13 ml/kg/h). We aimed to characterize how delivered HD dose and UFR are associated with survival in a large cohort of patients who started HD in childhood.

Methods

Retrospective analysis on a cohort of patients <30 years, on chronic HD since childhood (<19 years), having received thrice-weekly HD 2004–2016 in outpatient DaVita centers. Outcome: Survival while remaining on HD. Predictors: (I) primary analysis: mean delivered dialysis dose stratified as spKt/V ≤1.4/1.4–1.6/>1.6 (Kaplan–Meier analysis), (II) secondary analyses: UFR and alternative dialysis adequacy measures [eKt/V, body-surface normalized Kt/BSA] on continuous scale (Weibull regression model).

Results

A total of 1780 patients were included (age at the start of HD: 0–12y: n=321, >12–18y: n=1459; median spKt/V=1.55, eKt/V=1.31, Kt/BSA=31.2 L/m2, UFR=10.6 mL/kg/h). (I) spKt/V<1.4 was associated with lower survival compared to spKt/V>1.4–1.6 (P<0.001, log-rank test), and spKt/V>1.6 (P<0.001), with 10-year survival of 69.3% (59.4–80.9%) versus 83.0% (76.8–89.8%) and 84.0% (79.6–88.5%), respectively. (II) Kt/BSA was a better predictor of survival than spKt/V or eKt/V. UFR was additionally associated with survival (P<0.001), with increased mortality <10/>18 mL/kg/h. Associations did not alter significantly following adjustment for demographic characteristics (age, etiology of kidney disease, and ethnicity).

Conclusions

Our results suggest usefulness of targeting Kt/BSA>30 L/m2 for best long-term outcomes, corresponding to spKt/V>1.4 (>12 years) and >1.6 (<12 years). In contrast to adults, higher UFR of 10–18 ml/kg/h was not associated with greater mortality in this population.
Reduction of dust deposition in air-cooled condensers in thermal power plants by Ni–P-based coatings
Authors: Zhao Bo , Wang Xiaoxv , Xu Yongshao , Liu Bingzheng , Cao Shengxian , Zhao Qi
Published: March 2021

One of the largest problems with most current thermal power plants is the cooling efficiency. This paper aims to massively reduce fuel consumption and heat wasted in thermal power plants and hence CO2 emissions by resolving fouling issues associated with air-cooled condensers. In order to reduce the dust fouling deposition in the air-cooled condensers, the finned flat tubes were coated with nickel−phosphorus and nickel−phosphorus−polytetrafluoroethylene (Ni–P-PTFE) by an electroless coating technology. The anti-fouling performance of the coated tubes was investigated using the field operation parameters of air-cooled condensers, and the influence of the surface energies of the coatings on the dust adhesion was also investigated. The results demonstrated that the Ni–P coated finned tubes performed best, which reduced fouling resistance by 83.3% compared with the untreated finned tubes. The Ni–P coatings have potential applications in thermal power plants for reducing heat exchanger fouling and hence significantly decreasing waste heat and CO2 emissions.

Graphic abstract
Symmetry results for p-Laplacian systems involving a first-order term
Authors: Esposito Francesco , Merchán Susana , Montoro Luigi
Published: March 2021

In this paper we obtain symmetry and monotonicity results for positive solutions to some p-Laplacian cooperative systems in bounded domains involving first-order terms and under zero Dirichlet boundary condition.
Loss of endothelial glucocorticoid receptor promotes angiogenesis via upregulation of Wnt/β-catenin pathway
Authors: Liu Bing , Zhou Han , Zhang Tiening , Gao Xixiang , Tao Bo , Xing Hao , Zhuang Zhenwu , Dardik Alan , Kyriakides Themis R. , Goodwin Julie E.
Published: March 2021

Objective

The glucocorticoid receptor (GR) is a member of the nuclear receptor family that controls key biological processes in the cardiovascular system and has recently been shown to modulate Wnt signaling in endothelial cells. Wnt/β-catenin signaling has been demonstrated to be crucial in the process of angiogenesis. In the current study, we studied whether GR could regulate angiogenesis via the Wnt/β-catenin pathway.

Approach and Resultsa

Key components of the Wnt/β-catenin pathway were evaluated using quantitative PCR and Western blot in the presence or absence of GR. Enhanced angiogenesis was found in GR deficiency in vitro and confirmed with cell viability assays, proliferation assays and tube formation assays. Consistent with these in vitro findings, endothelial cell-specific GR loss GR in vivo promoted angiogenesis in both a hind limb ischemia model and sponge implantation assay. Results were further verified in a novel mouse model lacking endothelial LRP5/6, a key receptor in canonical Wnt signaling, and showed substantially suppressed angiogenesis using these same in vitro and in vivo assays. To further investigate the mechanism of GR regulation of Wnt signaling, autophagy flux was investigated in endothelial cells by visualizing auto phagolysosomes as well as by assessing P62 degradation and LC3B conversion. Results indicated that potentiated autophagy flux participated in GR-Wnt regulation.

Conclusions

Lack of endothelial GR triggers autophagy flux, leads to activation of Wnt/β-catenin signaling and promotes angiogenesis. There may also be a synergistic interaction between autophagy and Wnt/β-catenin signaling.
Feasibility and diagnostic reliability of quantitative flow ratio in the assessment of non-culprit lesions in acute coronary syndrome
Authors: Erbay Aslihan , Penzel Lisa , Abdelwahed Youssef S. , Klotsche Jens , Schatz Anne-Sophie , Steiner Julia , Haghikia Arash , Landmesser Ulf , Stähli Barbara E. , Leistner David M.
Published: March 2021

Several studies have demonstrated the feasibility and safety of hemodynamic assessment of non-culprit coronary arteries in setting of acute coronary syndromes (ACS) using fractional flow reserve (FFR) measurements. Quantitative flow ratio (QFR), recently introduced as angiography-based fast FFR computation, has been validated with good agreement and diagnostic performance with FFR in chronic coronary syndromes. The aim of this study was to assess the feasibility and diagnostic reliability of QFR assessment during primary PCI. A total of 321 patients with ACS and multivessel disease, who underwent primary PCI and were planned for staged PCI of at least one non-culprit lesion were enrolled in the analysis. Within this patient cohort, serial post-hoc QFR analyses of 513 non-culprit vessels were performed. The median time interval between primary and staged PCI was 49 [42–58] days. QFR in non-culprit coronary arteries did not change between acute and staged measurements (0.86 vs 0.87, p = 0.114), with strong correlation (r = 0.94, p ≤ 0.001) and good agreement (mean difference -0.008, 95%CI -0.013–0.003) between measurements. Importantly, QFR as assessed at index procedure had sensitivity of 95.02%, specificity of 93.59% and diagnostic accuracy of 94.15% in prediction of QFR ≤ 0.80 at the time of staged PCI. The present study for the first time confirmed the feasibility and diagnostic accuracy of non-culprit coronary artery QFR during index procedure for ACS. These results support QFR as valuable tool in patients with ACS to detect further hemodynamic relevant lesions with excellent diagnostic performance and therefore to guide further revascularisation therapy.
Using water hyacinth (Eichhornia crassipes) biomass and humic substances to produce urea-based multi-coated slow release fertilizer
Authors: Silva Iris Amanda A. , de Macedo Osmir Fabiano L. , Cunha Graziele C. , Oliveira Rhayza Victoria Matos , Romão Luciane P. C.
Published: March 2021

Urea-based multi-coated slow release fertilizer was produced using water hyacinth, humic substances, and chitosan, with water rich in natural organic matter as a solvent. Elemental analysis showed that the nitrogen content of the fertilizer (FERT) was around 20%. Swelling tests demonstrated the effectiveness of the water hyacinth crosslinker, which reduced the water permeability of the material. Leaching tests showed that FERT released a very low concentration of ammonium (0.82 mg L−1), compared to the amount released from urea (43.1 mg L−1). No nitrate leaching was observed for FERT, while urea leached 13.1 mg L−1 of nitrate. In water and soil, FERT showed maximum releases after 30 and 40 days, respectively, while urea reached maxima in just 2 and 5 days, respectively. The results demonstrated the promising ability of FERT to reduce nitrogen losses, as well as to minimize environmental impacts in the soil–plant-atmosphere system and to improve the efficiency of nitrogen fertilization.

Graphic abstract
Superabsorbent hydrogels enhanced by quaternized tunicate cellulose nanocrystals with adjustable strength and swelling ratio
Authors: Wei Peng , Chen Weiwei , Song Qinghua , Wu Yibing , Xu Youjia
Published: March 2021

Superabsorbent hydrogels were prepared from biodegradable material, where the matrix was cross-linked cellulose and carboxymethyl cellulose and reinforced by quaternized tunicate cellulose nanocrystals (Q-TCNCs). Due to the large amount of hydrophilic groups on cellulose, carboxymethyl cellulose, and Q-TCNCs, the hydrogels had excellent water absorption capacity. The equilibrium swelling ratio of superabsorbent hydrogels exceeded 500 g/g in deionized water and exceeded 120 g/g even in synthetic urine, which was higher than those of commercial absorbent materials composed of copolymers of acrylic acid and acrylamide. The water absorption performances and mechanical properties of the hydrogels could be adjusted by changing the content of Q-TCNCs. The resultant materials were expected to replace those polyolefin-based materials, thereby reducing environmental pollution.
Near-MDS codes from elliptic curves
Authors: Aguglia Angela , Giuzzi Luca , Sonnino Angelo
Published: March 2021

We provide a geometric construction of$$[n,9,n-9]_q$$[n,9,n-9]qnear-MDS codes arising from elliptic curves withn$${\mathbb {F}}_q$$Fq-rational points. Furthermore, we show that in some cases these codes cannot be extended to longer near-MDS codes.
Revisiting the Role of Worries in Explaining the Link Between Test Anxiety and Test Performance
Authors: Schillinger Frieder L. , Mosbacher Jochen A. , Brunner Clemens , Vogel Stephan E. , Grabner Roland H.
Published: March 2021

The inverse relationship between test anxiety and test performance is commonly explained by test-anxious students’ tendency to worry about a test and the consequences of failing. However, other cognitive facets of test anxiety have been identified that could account for this link, including interference by test-irrelevant thoughts and lack of confidence. In this study, we compare different facets of test anxiety in predicting test performance. Seven hundred thirty university students filled out the German Test Anxiety Inventory after completing a battery of standardized tests assessing general intelligence and mathematical competencies. Multiple regressions revealed that interference and lack of confidence but not worry or arousal explained unique variance in students’ test performance. No evidence was found for a curvilinear relationship between arousal and performance. The present results call for revisiting the role of worries in explaining the test anxiety-performance link and can help educators to identify students who are especially at risk of underperforming on tests.
variED: an editor for collaborative, real-time feature modeling
Authors: Kuiter Elias , Krieter Sebastian , Krüger Jacob , Saake Gunter , Leich Thomas
Published: March 2021

Feature models are a helpful means to document, manage, maintain, and configure the variability of a software system, and thus are a core artifact in software product-line engineering. Due to the various purposes of feature models, they can be a cross-cutting concern in an organization, integrating technical and business aspects. For this reason, various stakeholders (e.g., developers and consultants) may get involved into modeling the features of a software product line. Currently, collaboration in such a scenario can only be done with face-to-face meetings or by combining single-user feature-model editors with additional communication and version-control systems. While face-to-face meetings are often costly and impractical, using version-control systems can cause merge conflicts and inconsistency within a model, due to the different intentions of the involved stakeholders. Advanced tools that solve these problems by enabling collaborative, real-time feature modeling, analogous to Google Docs or Overleaf for text editing, are missing. In this article, we build on a previous paper and describe (1) the extended formal foundations of collaborative, real-time feature modeling, (2) our conflict resolution algorithm in more detail, (3) proofs that our formalization converges and preserves causality as well as user intentions, (4) the implementation of our prototype, and (5) the results of an empirical evaluation to assess the prototype’s usability. Our contributions provide the basis for advancing existing feature-modeling tools and practices to support collaborative feature modeling. The results of our evaluation show that our prototype is considered helpful and valuable by 17 users, also indicating potential for extending our tool and opportunities for new research directions.
A validated model for the scoping process of quality requirements: a multi-case study
Authors: Olsson Thomas , Wnuk Krzysztof , Jansen Slinger
Published: March 2021

Quality requirements are vital to developing successful software products. However, there exist evidence that quality requirements are managed mostly in an “ad hoc” manner and down-prioritized. This may result in insecure, unstable, slow products, and unhappy customers. We have developed a conceptual model for the scoping process of quality requirements – QREME – and an assessment model – Q-REPM – for companies to benchmark when evaluating and improving their quality requirements practices. Our model balances an upfront forward-loop with a data-driven feedback-loop. Furthermore, it addresses both strategic and operational decisions. We have evaluated the model in a multi-case study at two companies in Sweden and three companies in The Netherlands. We assessed the scoping process practices for quality requirements and provided improvement recommendations for which practices to improve. The study confirms the existence of the constructs underlying QREME. The companies perform, in the median, 24% of the suggested actions in Q-REPM. None of the companies work data-driven with their quality requirements, even though four out of five companies could technically do so. Furthermore, on the strategic level, quality requirements practices are not systematically performed by any of the companies. The conceptual model and assessment model capture a relevant view of the quality requirements practices and offer relevant improvement proposals. However, we believe there is a need for coupling quality requirements practices to internal and external success factors to motive companies to change their ways of working. We also see improvement potential in the area of business intelligence for QREME in selecting data sources and relevant stakeholders.
TPOT-NN: augmenting tree-based automated machine learning with neural network estimators
Authors: Romano Joseph D. , Le Trang T. , Fu Weixuan , Moore Jason H.
Published: March 2021

Automated machine learning (AutoML) and artificial neural networks (ANNs) have revolutionized the field of artificial intelligence by yielding incredibly high-performing models to solve a myriad of inductive learning tasks. In spite of their successes, little guidance exists on when to use one versus the other. Furthermore, relatively few tools exist that allow the integration of both AutoML and ANNs in the same analysis to yield results combining both of their strengths. Here, we present TPOT-NN—a new extension to the tree-based AutoML software TPOT—and use it to explore the behavior of automated machine learning augmented with neural network estimators (AutoML+NN), particularly when compared to non-NN AutoML in the context of simple binary classification on a number of public benchmark datasets. Our observations suggest that TPOT-NN is an effective tool that achieves greater classification accuracy than standard tree-based AutoML on some datasets, with no loss in accuracy on others. We also provide preliminary guidelines for performing AutoML+NN analyses, and recommend possible future directions for AutoML+NN methods research, especially in the context of TPOT.
Teaching digital models: secondary technology teachers’ experiences
Authors: Brink Helen , Kilbrink Nina , Gericke Niklas
Published: March 2021

In secondary technology education, models of artifacts, systems and processes, visualized and simulated through digital tools (digital models) are a relatively new element. Technology teachers teach digital models to meet syllabus criteria of digital competence, applicable to for instance problem solving and documentation using digital tools. However, there is a lack of knowledge concerning how teachers use digital models in their teaching, what their intentions are, and what content they choose. It is known, though, that teachers’ experiences influence the teaching. Therefore, the aim of this study is to investigate teachers’ experiences of teaching digital models in compulsory school, to contribute to more knowledge of teaching in this area. This study takes a phenomenological lifeworld approach, and 12 semi-structured interviews with lower secondary technology teachers form the empirical data. The data were analyzed thematically and the results are four themes of experiencing the teaching of digital models, indicating that technology teachers teach with different aims and purposes; Enhancing and integrating other subjects, Visualizing technology to the pupils, Enabling digital modelling, and Preparing pupils for the future. Further, the results also indicate that the content and methods of teaching differ and that teachers did not experience digital models as one single idea but as an amalgam of multiple ideas. These findings can be used as a basis for further research and development of teaching concerning digital models.
Correction to: Contextual Application of Pulse-Compression and Multi-frequency Distance-Gain Size Analysis in Ultrasonic Inspection of Forging
Authors: Rizwan M. K. , Senni L. , Burrascano P. , Laureti S. , Goldammer M. , Mooshofer H. , Borgna R. , Neri S. , Ricci M.
Published: March 2021

The article “Contextual Application of Pulse-Compression and Multi-frequency Distance-Gain Size Analysis”.
Some Remarks on Replicated Simulated Annealing
Authors: Gripon Vicent , Löwe Matthias , Vermet Franck
Published: March 2021

Recently authors have introduced the idea of training discrete weights neural networks using a mix between classical simulated annealing and a replica ansatz known from the statistical physics literature. Among other points, they claim their method is able to find robust configurations. In this paper, we analyze this so called “replicated simulated annealing” algorithm. In particular, we give criteria to guarantee its convergence, and study when it successfully samples from configurations. We also perform experiments using synthetic and real data bases.
Soft biometrics: a survey
Authors: Hassan Bilal , Izquierdo Ebroul , Piatrik Tomas
Published: March 2021

The field of biometrics research encompasses the need to associate an identity to an individual based on the persons physiological or behaviour traits. While the use of intrusive techniques such as retina scans and finger print identification has resulted in highly accurate systems, the scalability of such systems in real-world applications such as surveillance and border security has been limited. As a branch of biometrics research, the origin of soft biometrics could be traced back to need for non-intrusive solutions for extracting physiological traits of a person. Following high number of research outcomes reported in the literature on soft biometrics, this paper aims to consolidate the scope of soft biometrics research across four thematic schemes (i) a detailed review of soft biometrics research data sets, their annotation strategies and building a largest novel collection of soft traits; (ii) the assessment of metrics that affect the performance of soft biometrics system; (iii) a comparative analysis on feature and modality level fusion reported in the literature for enhancing the system performance; and (iv) a performance analysis of hybrid soft biometrics recognition system using multi-scale criterion. The paper also presents a detailed analysis on the global traits associated to person identity such as gender, age and ethnicity. The contribution of the paper is to provide a comprehensive review of scientific literature, identify open challenges and offer insights on new research directions in the filed.
Fractional-order single state reset element
Authors: Karbasizadeh Nima , Saikumar Niranjan , HosseinNia S. Hassan
Published: March 2021

This paper proposes a fractional-order reset element whose architecture allows for the suppression of nonlinear effects for a range of frequencies. Suppressing the nonlinear effects of a reset element for the desired frequency range while maintaining it for the rest is beneficial, especially when it is used in the framework of a “Constant in gain, Lead in phase” (CgLp) filter. CgLp is a newly introduced nonlinear filter, bound to circumvent the well-known linear control limitation—the waterbed effect. The ideal behaviour of such a filter in the frequency domain is unity gain while providing a phase lead for a broad range of frequencies. However, CgLp’s ideal behaviour is based on the describing function, which is a first-order approximation that neglects the effects of the higher-order harmonics in the output of the filter. Although CgLp is fundamentally a nonlinear filter, its nonlinearity is not required for all frequencies. Thus, it is shown in this paper that using the proposed reset element architecture, CgLp gets closer to its ideal behaviour for a range of frequencies, and its performance will be improved accordingly.
Multi-degree-of-freedom systems with a Coulomb friction contact: analytical boundaries of motion regimes
Authors: Marino Luca , Cicirello Alice
Published: March 2021

This paper proposes an approach for the determination of the analytical boundaries of continuous, stick-slip and no motion regimes for the steady-state response of a multi-degree-of-freedom (MDOF) system with a single Coulomb contact to harmonic excitation. While these boundaries have been previously investigated for single-degree-of-freedom (SDOF) systems, they are mostly unexplored for MDOF systems. Closed-form expressions of the boundaries of motion regimes are derived and validated numerically for two-degree-of-freedom (2DOF) systems. Different configurations are observed by changing the mass in contact and by connecting the rubbing wall to: (i) the ground, (ii) the base or (iii) the other mass. A procedure for extending these results to systems with more than 2DOFs is also proposed for (i)–(ii) and validated numerically in the case of a 5DOF system with a ground-fixed contact. The boundary between continuous and stick-slip regimes is obtained as an extension of Den Hartog’s formulation for SDOF systems with Coulomb damping (Trans Am Soc Mech Eng 53: 107–115, 1931). The boundary between motion and no motion regimes is derived with an ad hoc procedure, based on the comparison between the overall dynamic load and the friction force acting on the mass in contact. The boundaries are finally represented in a two-dimensional parameter space, showing that the shape and the extension of the regions associated with the three motion regimes can change significantly when different physical parameters and contact configurations are considered.
Some double-angle formulas related to a generalized lemniscate function
Authors: Takeuchi Shingo
Published: March 2021

In this paper, we will establish some double-angle formulas related to the inverse function of $$\int _0^x \text {d}t/\sqrt{1-t^6}$$

∫
0
x

d
t
/

1
-

t
6

. This function appears in Ramanujan’s Notebooks and is regarded as a generalized version of the lemniscate function.
Burst Detection by Water Demand Nowcasting Based on Exogenous Sensors
Authors: Geelen Caspar V. C. , Yntema Doekle R. , Molenaar Jaap , Keesman Karel J.
Published: March 2021

Bursts of drinking water pipes not only cause loss of drinking water, but also damage below and above ground infrastructure. Short-term water demand forecasting is a valuable tool in burst detection, as deviations between the forecast and actual water demand may indicate a new burst. Many of burst detection methods struggle with false positives due to non-seasonal water consumption as a result of e.g. environmental, economic or demographic exogenous influences, such as weather, holidays, festivities or pandemics. Finding a robust alternative that reduces the false positive rate of burst detection and does not rely on data from exogenous processes is essential. We present such a burst detection method, based on Bayesian ridge regression and Random Sample Consensus. Our exogenous nowcasting method relies on signals of all nearby flow and pressure sensors in the distribution net with the aim to reduce the false positive rate. The method requires neither data of exogenous processes, nor extensive historical data, but only requires one week of historical data per flow/pressure sensor. The exogenous nowcasting method is compared with a common water demand forecasting method for burst detection and shows sufficiently higher Nash-Sutcliffe model efficiencies of 82.7% - 90.6% compared to 57.9% - 77.7%, respectively. These efficiency ranges indicate a more accurate water demand prediction, resulting in more precise burst detection.
Toxicity mitigation by N-acetylcysteine and synergistic toxic effect of nano and bulk ZnO to Panagrellus redivivus
Authors: Kiss Lola Virág , Sávoly Zoltán , Ács András , Seres Anikó , Nagy Péter István
Published: March 2021

To better understand the nanosize-relevant toxic effects and underlying mechanisms, N-acetylcysteine (NAC), as a mitigation agent, an ionic form of Zn (ZnCl2), and the binary mixture of ZnO with different particle sizes (15 nm and 140 nm), was used in toxicity assays with the nematode Panagrellus redivivus. The ZnCl2 concentrations were applied to show the amount of dissolved Zn ions present in the test system. Reactive oxygen species (ROS) measuring method was developed to fit the used test system. Our studies have shown that NAC can mitigate the toxic effects of both studied particle sizes. In the applied concentrations, ZnCl2 was less toxic than both of the ZnO particles. This finding indicates that not only ions and ROS produced by the dissolution are behind the toxic effects of the ZnO NPs, but also other particle size-dependent toxic effects, like the spontaneous ROS generation, are also relevant. When the two materials were applied in binary mixtures, the toxic effects increased significantly, and the dissolved zinc content and the ROS generation also increased. It is assumed that the chemical and physical properties of the materials have been mutually reinforcing to form a more reactive mixture that is more toxic to the P. redivivus test organism. Our findings demonstrate the importance of using mitigation agent and mixtures to evaluate the size-dependent toxicity of the ZnO.

Graphical abstract
Correlation between polio immunization coverage and overall morbidity and mortality for COVID-19: an epidemiological study
Authors: Afify Marwa Adel , Alqahtani Rakan M. , Alzamil Mohammed Abdulrahman Mohammed , Khorshid Faten Abdulrahman , Almarshedy Sumayyah Mohammad , Alattas Sana Ghazi , Alrawaf Talal Nabeel , Bin-Jumah May , Abdel-Daim Mohamed M. , Almohideb Mohammad
Published: March 2021

We conducted the current analysis to determine the potential role of polio vaccination in the context of the spread of COVID-19. Data were extracted from the World Health Organization’s (WHO) Global Health Observatory data repository regarding the polio immunization coverage estimates and correlated to the overall morbidity and mortality for COVID-19 among different countries. Data were analyzed using R software version 4.0.2. Mean and standard deviation were used to represent continuous variables while we used frequencies and percentages to represent categorical variables. The Kruskal-Wallis H test was used for continuous variables since they were not normally distributed. Moreover, the Spearman rank correlation coefficient (rho) was used to determine the relationship between different variables. There was a significantly positive correlation between the vaccine coverage (%) and both of total cases per one million populations (rho = 0.37; p-value < 0.001) and deaths per one million populations (rho = 0.30; p-value < 0.001). Moreover, there was a significant correlation between different income groups and each of vaccine coverage (%) (rho = 0.71; p-value < 0.001), total cases per one million populations (rho = 0.50; p-value < 0.001), and deaths per one million populations (rho = 0.39; p-value < 0.001). All claims regarding the possible protective effect of Polio vaccination do not have any support when analyzing the related data. Polio vaccination efforts should be limited to eradicate the disease from endemic countries; however, there is no evidence to support the immunization with live-attenuated vaccines for the protection against COVID-19.