bluuebunny/crossref_metadata_2025 huggingface dataset:
Bézier extraction based isogeometric approach to multi‐objective topology optimization of periodic microstructures
Authors: Zhuang Chungang , Xiong Zhenhua , Ding Han
Published: August 2021

This article presents the Bézier extraction based isogeometric approach to multi‐objective topology optimization of periodic microstructures. The approach utilizes the B‐splines based Bézier elements as the finite element representation at both macro and micro levels. The equivalent elastic properties of the representative volume element (RVE) are computed by the numerical homogenization method with the periodic boundary conditions on the control points (CPs) of the B‐spline mesh. The multi‐objective optimization problems including the material bulk modulus maximization, negative Poisson's ratio, and concurrent topology optimization of the composite structures are formulated by using the Bézier elements based isogeometric analysis. The distance‐based density distribution on the CPs of the B‐spline mesh is proposed as the initialization for designing the RVE, which is more robust than the uniform density distribution towards the optimal results. Several numerical examples are presented to illustrate the effectiveness of the proposed approach, and a variety of isotropic and anisotropic RVEs and composite structures are obtained. Meanwhile, various influences on the optimal design of the RVE and macrostructure are also discussed.
The dynamics of link between entrepreneurship, government support and economic growth: Evidence from BRICS countries
Authors: Rani Ritu , Kumar Naresh
Published: August 2021

The aim of the study is to investigate the dynamics of link between supporting role of BRICS governments in promoting economic growth through entrepreneurship. This paper employs 15 years annual time series data (2004–2018) for five BRICS countries: Brazil, Russia, India, China and South Africa. The study is based on secondary data collected from World Development Indicators (WDI), Global Entrepreneurship Monitor (GEM), Worldwide Governance Indicators (WGI), and Global Entrepreneurship and Development Institute (GEDI). The study revealed that institutional factors (government effectiveness, domestic credit, and perception about opportunities) have an optimistic and considerable impact on entrepreneurial activities in BRICS countries and combination of these three is important to sustainability of the business in today's dynamic environment. Further, ease to access the physical resources, corruption, and public utilities have negative impact on entrepreneurship in these economies. The study also explored that entrepreneurial activities have constructive and noteworthy impact on economic growth in BRICS nations. An entrepreneurial ecosystem is required within each country to sustain novel, dynamic, and swiftly mounting new ventures. The study is unique as it elucidated the significant role of government effectiveness, role of domestic credit, perception about opportunities, ease to access the physical resources, and corruption in promoting the entrepreneurial culture in BRICS economies. Additionally, the study also clarified the imperative function of entrepreneurial activities in overall growth of BRICS economies.
The forms of decommodification and (de)familisation measures during COVID‐19: What is the impact on female's welfare?
Authors: Yuda Tauchid Komara , Rezza Muhammad
Published: August 2021

Using the decommodification and (de)familisation framework, this paper examines the two main Social Safety Net programme during the pandemic and its effect on female welfare in Indonesia. It is argued that despite expansion of decommodification measures through unemployment benefits, females tend to benefit less because the existing labour force structure is highly dominated by males. Hence, the only way of being financially secure is to have access to Conditional Cash Transfer (CCT), which means it then exposes them to greater risk of familisation. This is because to be eligible for CCT, they are (informally) required to perform unpaid caregiving. This article concludes that familial ethics has become a rationale for the state to push females to seek social support through a family relationship, resulting in social risk internalisation during the COVID‐19 crisis, rather granting them citizenship rights‐based welfare.
Interpreting lived experiences: The dilemmas of public sector leaders
Authors: Masud Mehedi , Hossain Md. Rakib
Published: August 2021

Dilemmas are a useful concept for exploring leadership practices and decision‐making process. Preserving the integrity of the state and yet to be representative—this classic dilemma is faced by Bangladeshi Public Sector Leaders (PSLs). Taking an interpretive approach, this research presents empirical insights in an important subfield of public administration, namely, lived experiences of PSL about the public sector reforms and governance practice. The researchers administered in‐depth interviews and Focus Group Discussion (FGD). What emerged as the salient dilemmas of PSLs are: the dilemma of public sector leadership: the colonial legacy, power relationship dilemma in the system of government, domestic reform strategy versus donor reform strategy, public interest versus vested interest and lastly, commitment versus service to multiple stakeholders. It also identified that there is a significant presence of NPM overtones in the PSL response towards the reform programme that illustrates the prominent features of decentralization and bureaucratic entrepreneurship.
Shape memory polymers as actuators: Characterization of the relevant parameters under constrained recovery
Authors: Peixoto Carina , Zille Andrea , Ferreira da Silva Alexandre , Carneiro Olga Sousa
Published: August 2021

In this work, a shape memory polyurethane is characterized through constrained recovery experiments performed in a tensile testing equipment. The most relevant results obtained are those concerned with the stress released over time during the recovery stage, since they provide quantitative information that can be used in the design of actuators. For this sake, design guidelines are proposed based on the effect of: (i) the programming temperature; (ii) the deformation imposed during the programming stage; (iii) the recovery temperature; and (iv) the manufacturing process used to produce the samples tested (compression molding and Fused Filament Fabrication). The set of experiments performed with compression‐molded samples put in evidence a considerable variety of material responses: (i) the maximum released stress varied from 0.74 to 1.68 MPa; (ii) the time required to attain this stress varied from 47 to 600 s; and (iii) the stress was released as a peak value that relaxed rapidly, or, contrarily, had a lasting effect. Another relevant conclusion is that the 3D printing technique does not affect the shape memory behavior of the material. Having this in mind, the conclusions provided by the compression‐molded samples study can be extended to printed ones.
Stepwise surface modification of mesoporous silica and its use in poly(urethane‐urea) composite films
Authors: Fakhar Afsaneh , Sadeghi Morteza , Dinari Mohammad
Published: August 2021

The compatibility between polymer matrix and filler is a vital issue in the fabrication of composites with desirable properties. To enhance the interfacial adhesion between matrix and filler, various surface modification treatments are applied. The objective of this study was to increase the affinity of silica and poly(urethane‐urea)s (PUUs), thereby improving the mechanical properties of the resulting composites. Stepwise surface modification of mesoporous silica with amine‐containing dendrimers was done. Various techniques were used to confirm the surface‐modified structure during the stepwise reaction. Additionally, the N2 adsorption–desorption method indicated a gradual reduction in surface area, pore diameter and pore volume of the particles, which warrants the gradual propagation of the dendrimers on the surface and also inside the pores. A type IV isotherm was obtained in this analysis. Two types of pre‐synthesized PUUs were chosen for composite preparation containing the surface‐modified silica with 0.5, 1, 2.5 and 5 wt% concentrations. Due to the high affinity of the dendrimers containing amine moieties on the particles with polyurethane, a proper dispersion of particles in the matrix was achieved based on scanning electron micrographs. Tensile measurements showed an increased Young's modulus and strength of polyurethane films as a result of addition of the particles. However, no significant improvement in the tensile performance of the composites was seen above 2.5 wt% particle loading due to some particle aggregations. © 2021 Society of Industrial Chemistry.
Preliminary validation of a questionnaire assessing psychological distress in caregivers of patients with malignant mesothelioma: Mesothelioma Psychological Distress Tool—Caregivers
Authors: Bonafede Michela , Chiorri Carlo , Azzolina Danila , Marinaccio Alessandro , Migliore Enrica , Mensi Carolina , Chellini Elisabetta , Romeo Elisa , Grosso Federica , Franzoi Isabella Giulia , Granieri Antonella , Guglielmucci Fanny
Published: August 2021

Objective

To develop a short, flexible, and comprehensive tool to measure psychological distress in caregivers of malignant mesothelioma (MM) patients: the Mesothelioma Psychological Distress Tool—Caregivers version (MPDT‐C).

Methods

Based on a systematic review of the relevant literature, aspects associated with caregiver distress were derived. Expert researchers/clinicians developed a pool of items for each identified aspect. Content validity was assessed through a multiple mixed‐methods approach. A multicenter study was conducted to explore the factorial structure of the 47‐item MPDT‐C through Bayesian factor analysis.

Results

The Bayesian exploratory factor analysis revealed an underlying three‐factor structure. Factors were labeled Secondary Traumatic Stress, Engagement in Caring, and Meaningful Cognitive Restructuring. All scales showed sufficient reliability and corrected item–total correlations. Females scored higher than males for Engagement in Caring.

Conclusions

Taking care of malignant mesothelioma patients is a stressful process that influences the caregiver's physical, emotional, and social wellbeing. Our study offers preliminary evidence in support of the adequate psychometric properties of the MPDT‐C, and these should now be replicated. Results suggest that the MPDT‐C is a reliable tool with which to detect the psychological distress of this traumatized population.
Broadcasting of tiny granules by drone to mimic liquid spraying for the control of fall armyworm (Spodoptera frugiperda)
Authors: Yan Xiaojing , Yuan Huizhu , Chen Yixuan , Shi Xin , Liu Xiaohui , Wang Zhenying , Liu Yue , Yang Daibin
Published: August 2021

BACKGROUND

The fall armyworm (FAW), Spodoptera frugiperda (J. E. Smith), is an invasive pest. Maize is one of its preferred host plants. The traditional application of granules has been effective for the control of FAW. Nevertheless, the challenge is to develop an application method that is less labor‐intensive and also efficient.

RESULTS

Tiny granules in the size range of 0.38–0.55 mm were prepared by the centrifugal granulation method for drone application. The in‐swath distribution patterns of granules deposited on sticky tapes were similar to the distribution of aqueous droplets through drone spraying. In the range of 1.5–3.5 m, a relatively higher aircraft height of flight can provide a more uniform distribution pattern of deposited granules, but resulted in less deposit of tiny granules in the whorl of maize plants. Similarly, the deposit of granules in the whorl of maize plants significantly decreased when the flight speed increased from 4 to 6 m s−1. Granules gathered in the whorl accounted for 50.8–58.7% of total granules deposited in the maize canopy. The field experiment demonstrates granular formulations (containing 0.25% chlorantraniliprole + 0.15% emamectin benzoate, or higher concentrations) can provide better and longer duration of FAW control than the aqueous spray formulation at the whorl stage of maize plants.

CONCLUSION

Broadcasting of tiny granules by drone can provide better FAW control than liquid spray. The architecture of the maize plant and the downward airstream of the drone create favorable conditions for the deposition of granules in whorls. © 2021 Society of Chemical Industry.
Migrant subjectivities and temporal flexibility of East‐Central European labour migration to the United Kingdom
Authors: Shubin Sergei , McCollum David
Published: August 2021

This paper seeks to broaden existing understandings of migrant worker flexibility drawing on the data from the two ethnographic studies of low‐wage employers and Eastern European migrants in Scotland. It focuses on the temporal aspects of flexibility production in employment discourse and temporal expectations about flexible migrant workers. Our findings reveal double movement of interruption and remaking of temporal flexibility, which challenges directional expectations about time and unsettles the assumed connectivity between flexibility's temporal elements. Uncertainty and instability of migration and employment frameworks undermine the attempts of employers and migrants to manage time, to develop continuous portfolio careers and coherent temporal horizons. Furthermore, contested temporal expectations about flexible migrant workers create fragmented and fractured “flexiworkers” that do not fit within the existing temporal frameworks of signs, routines, and rhythms. The paper suggests re‐orientation of flexibility debates beyond temporal measurement, outside familiar temporal structures, and towards redefinition of flexible worker identities.
Durable conversions: Property, aspiration, and inequality in urban northern Kenya
Authors: Elliott Hannah
Published: August 2021

In Isiolo, a northern Kenyan town earmarked for development as part of a large‐scale infrastructure project, the value of land has increased dramatically. Local residents with insecure tenure at the town's edges were selling off plots at ever‐rising prices. Yet the money generated was renowned for its rapid expenditure, leaving the holder with little to show for the sale. This article examines the discourse of “selling and building,” whereby residents aspired to discipline flighty money generated through land sale by converting it into durable investments. In particular, selling and building was seen as a means of strengthening individual property claims: By selling a little land, one could invest the money it yielded in the remainder, most often by building a “permanent” house. Yet “selling and building” was an individual, private property solution to the collective problem of insecure customary tenure and worked to gloss over and perpetuate inequalities among residents. The problems associated with the “money of plots” (pesa ya ploti), and struggles with building, attest to the complexity of property relations in urbanizing northern Kenya as historically collective and prospectively individual. Moreover, they illuminate residents' deep ambivalence about private property and the inequalities inherent to it.
Combining topography and peptide to inhibit algae attachment: Preparation of peptide‐modified microstructured surfaces
Authors: Cao Pan , Liu De , Liu Yuhan , Zhang Yan , Yuan Chengqing , Zhang Chao
Published: August 2021

Marine facilities and ships are easily plagued by biofouling. Synergistic surfaces combining surface reactive ion etching and peptide modification were designed and prepared to tackle surface biofouling. Six microstructural surfaces were first designed and machined based on the contact point theory; the synergistic surfaces were then prepared by peptide modification. Laser confocal scanning microscope (LCSM), scanning electron microscopy (SEM), contact angle measurement, and X‐ray photoelectron spectroscopy (XPS) were utilized to analyze the surface morphology and surface chemical properties; the results demonstrated that six synergistic surfaces were prepared successfully with 0.8‐μm depth, surface contact angle increased from 75° to 116.99°, and the surface chemical compositions were also changed significantly due to peptide modification. Antibiofilm assays showed that surface modification and surface topology could slightly reduce the formation of biofilm. While the synergistic surfaces possess strong anti‐algal performance, and anti‐Chlorella pyrenoidosa (C. pyrenoidosa) and anti‐Phaeodactylum tricornutum (P. tricornutum) rates reached 78.56% and 87.80%, respectively after 7‐day immersion in artificial seawater. Compared with the single surface treatment method, the antifouling performance of the synergetic surfaces were stronger. This strategy demonstrated a realistic paradigm for the further improving surface antifouling performance in a green method.
Study of buried interfaces in Fe/Si multilayer by hard x‐ray emission spectroscopy
Authors: Verma Hina , Le Guen Karine , Delaunay Renaud , Ismail Iyas , Ilakovac Vita , Rueff Jean Pascal , Zheng Yunlin Jacques , Jonnard Philippe
Published: August 2021

Hard x‐ray emission spectroscopy (XES) has been used to study buried layers and interfaces in a Fe/Si periodic multilayer. Until now, buried layers could be studied using the XES in the soft x‐ray range. Here, we extend the methodology to study the buried interfaces in hard x‐ray region (photon energy ≥ 5 keV). We report the formation of FeSi2 at all the interfaces with thicknesses of 1.4 nm. X‐ray reflectivity measurements enable us to deduce the structure and thickness of the multilayer stack, thereby confirming the presence of FeSi2.
A Novel Stacked Rotary Cup Atomizer Toward Efficient Centrifugal Granulation of Molten Blast Furnace Slag
Authors: Tan Yu , Zhu Xun , Wang Hong , Lv Yi-Wen , Ding Yu-Dong , Liao Qiang
Published: August 2021

Atomizer is one of the most important facilities in molten slag centrifugal granulation heat recovery system, which concerns the heat recovery rate of the system as well as the quality of slag particles. Aim to large slag flow rate in industrial application, a novel stacked rotary cup atomizer (SRCA) is proposed to achieve high‐quality centrifugal granulation performance. The authentic molten slag is adopted as working medium and the centrifugal granulation phenomena are visually investigated including the molten slag fragmentation on the surface of atomizer and the impacting of slag droplets on the water cooled wall. A film perforation fragmentation mode is found in the experiments under high slag flow rate. The granulated particle size distribution, average particle size, and slagging mass fraction produced by the atomizer are obtained. Moreover, the granulation performances of the SRCA with divergent structures are tested. The results demonstrate that the SRCA has excellent granulation performance in large slag flow rate to produce smaller particles and suppress slagging. Comparing with the typical rotary cup atomizer, the largest decrement in average particle size and slagging mass fraction for the SRCA is ascertained as 28.1% and 71.1%, respectively.
Study on Splashing Mechanism in Basic Oxygen Furnace Based on Slag Foaming Modeling
Authors: Wang Ruifang , Zhang Bo , Hu Chao , Liu Chengjun , Jiang Maofa
Published: August 2021

Inappropriate slag foaming is the main cause of splashing in basic oxygen furnace (BOF). Through the physical modeling, the effects of slag–metal reaction rate, viscosity of slag, slag–metal interface tension, and lance height on the slag foaming are investigated, and further analyzed the relation between the extent of BOF slag foaming and splashing. Consequently, two patterns of overflowing splashing and eruptive splashing and their critical conditions are summarized. The experimental results indicate that gas released by slag–metal reaction is primarily responsible for slag foaming in BOF, and the maximum height of foamed slag increases with increasing reaction rate of slag–metal. Moreover, an increase in dynamic viscosity of slag prevents the foam structure transforming from spherical foam to polyhedral foam, and thus improves the maximum foaming ability of slag and the stability of foam structure. With decreasing slag–metal interface tension, the slag–metal emulsification and the stability of foam structure are promoted. Finally, it is concluded that overflowing splashing occurs under the conditions of the higher dynamic viscosity of slag and the larger gas generation amount; whereas, eruptive splashing occurs under the conditions of the lower dynamic viscosity of slag and the higher gas generation rate.
Production of Niobium Carbide Layers on High‐Strength Bainitic Steels by Thermochemical Treatment of Thermoreactive Diffusion Followed by Austempering
Authors: de Oliveira Pedro Gabriel Bonella , Triani Rafael Magalhães , Filho André Itman , Neto Amadeu Lombardi , Totten George E. , Casteletti Luiz Carlos
Published: August 2021

The development of third‐generation advanced high‐strength steels aims for the production of low‐alloy steels with a high strength‐to‐weight ratio through innovative heat treatments. Thermochemical treatments that eliminate reheating steps are an excellent alternative for the surface hardening of this type of alloy. Herein, the incorporation of a thermoreactive diffusion (TRD) thermochemical treatment along with austempering treatment to obtain carbide‐coated high‐strength bainitic steels is evaluated. For this purpose, samples of bainitic steels containing ≈1.5 wt% silicon are immersed in an austenitizing bath composed of ferro‐niobium and sodium borate for 2, 4, and 6 h at 1100 °C. Subsequently, they are held isothermally in a 360 °C salt bath for 1 h. After treatment, the samples are characterized by optical microscopy, scanning electron microscopy, X‐ray diffraction, dispersive energy spectroscopy, Knoop microhardness, and microadhesive wear tests. Microstructural analysis shows the formation of niobium carbide layers at the surface of a substrate composed of granular and plate bainite, characteristic of austempered high‐silicon steels. These layers show thickness in the range of 4−9 μm, hardness from 2333 to 2599 HK, presenting hardness up to 6 times higher than the substrates, and wear resistance up to 8 times greater.
Replacement of the Typical artedi Form of Cisco Coregonus artedi in Lake Huron by Endemic Shallow‐Water Ciscoes, Including Putative Hybrids
Authors: Eshenroder Randy L. , Kao Yu‐Chun , O’Brien Timothy P. , Olds Chris M. , Davis Chris L. , Duncan Alexander T.
Published: August 2021

Various ecomorphs of the shallow‐water Cisco Coregonus artedi were the dominant fish planktivores in each of the Great Lakes until invasive species and overfishing resulted in extirpations and extinctions. In this paper, we describe the present morphological diversity and distribution of shallow‐water Ciscoes in each of Lake Huron’s three basins: the main basin, Georgian Bay, and the North Channel. Typical artedi, a formerly widespread ecomorph that had supported the lake’s largest fishery, appears to have been extirpated from all three basins. Three types of shorthead cisco, a recently described and variable ecomorph, were extant. One type was morphologically robust and abundant along the north rim of the lake. The second type was large bodied, terete (streamlined), short finned, and collected at only one location in the main basin. The third type consisted of putative shorthead cisco × typical artedi hybrids, which were widespread in Georgian Bay and the North Channel. Only the putative hybrids were regularly collected in midwater trawls, suggesting that they were more pelagic, which we attribute to an inferred partial ancestry with typical artedi. The putative shorthead cisco × typical artedi hybrids of Georgian Bay and the North Channel have replaced typical artedi to some degree, while shorthead ciscoes in the main basin, though possibly more abundant now than in the past, have not measurably replaced typical artedi. Even with the apparent extirpation of typical artedi, Lake Huron has a greater diversity of shallow‐water Ciscoes than any of the other Great Lakes, which we attribute to its more complex topography.
“Well that's how the kids feel!”—Epistemic empathy as a driver of responsive teaching
Authors: Jaber Lama Z. , Dini Vesal , Hammer David
Published: August 2021

While research shows that responsive teaching fosters students' disciplinary learning and equitable opportunities for participation, there is yet much to know about how teachers come to be responsive to their students' experiences in the science classroom. In this work, we set out to examine whether and how engaging teachersas learnersin doing science may support responsive instructional practices. We draw on data from a year‐long blended‐online science professional development (PD) program that began with an emphasis on teachers' doing science and progressed to supporting their attention to their students' doing science. By analyzing videos from teachers' classrooms collected throughout the PD, we found that teachers became more stable in attending and responding to their students' thinking. In this article, we present evidence from teachers' reflections that this stability was supported by the teachers' intellectual and emotional experiences as learners. Specifically, we argue that engaging in extended scientific inquiry provided a basis for the teachers havingepistemic empathyfor their students—their tuning into and appreciating their students'intellectualandemotionalexperiences in science, which in turn supported teachers' responsiveness in the classroom.
Some modelling improvements for prediction of wind turbine rotor loads in turbulent wind
Authors: Muñoz‐Simón Arturo , Palacios Rafael , Wynn Andrew
Published: August 2021

This paper investigates the accuracy of three aerodynamic models to compute loads on wind turbine rotors under turbulent inflow: Blade Element Momentum (BEM), Unsteady Vortex Lattice Method (UVLM), and Large Eddy Simulation with Actuator Line (LES‐AL). Turbulent inflow conditions are numerically generated with a new approach that combines control of turbulence and realistic velocity spectrum by using Mann boxes and LES simulations, respectively. Several deficiencies of the tested models are found and overcome through proposed improvements. First, the BEM assumption of independent radial sections does not hold in turbulent cases with long blades. Thus, a spatial filter to account for the interaction of radial sections in BEM is designed through the analysis of these interactions with UVLM. Second, the absence of viscous drag in UVLM is observed to lead to a very high rotor power coefficient, and it is shown that this can be mitigated by including drag in UVLM with a BEM‐like‐approach through look‐up tables. Third, the free wake model in UVLM, required to accurately capture rotor thrust, significantly increases computational cost. For this reason, a new wake discretisation scheme for the wake convection equation in UVLM is proposed, in which a coarse discretisation is employed far from the solid surfaces, which significantly reduces the computational time. Finally, these improvements and the performance of the three fidelities are analysed in a reference 10 MW wind turbine rotor demonstrating, in general, good agreement.
Recent advances and applications of microspheres and nanoparticles in transarterial chemoembolization for hepatocellular carcinoma
Authors: Jia Guorong , Van Valkenburgh Juno , Chen Austin Z. , Chen Quan , Li Jindian , Zuo Changjing , Chen Kai
Published: August 2021

Transarterial chemoembolization (TACE) is a recommended treatment for patients suffering from intermediate and advanced hepatocellular carcinoma (HCC). As compared to the conventional TACE, drug‐eluting bead TACE demonstrates several advantages in terms of survival, treatment response, and adverse effects. The selection of embolic agents is critical to the success of TACE. Many studies have been performed on the modification of the structure, size, homogeneity, biocompatibility, and biodegradability of embolic agents. Continuing efforts are focused on efficient loading of versatile chemotherapeutics, controlled sizes for sufficient occlusion, real‐time detection intra‐ and post‐procedure, and multimodality imaging‐guided precise treatment. Here, we summarize recent advances and applications of microspheres and nanoparticles in TACE for HCC.

This article is categorized under:

Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease
Short comments on chaotic behavior of a double pendulum with two subharmonic frequencies and in the main resonance zone
Authors: Avanço Rafael Henrique , Balthazar José Manoel , Tusset Ângelo Marcelo , Ribeiro Mauricio Aparecido
Published: August 2021

The parametric pendulum and others different pendular mechanisms were extensively analyzed in current literature because of the chaotic motions. Recently, practical reasons, like energy harvesting, motivated the study of some pendular systems. The resonance and the chaos may occur in multiple and submultiple frequencies based on the natural frequency of the pendulum. In the present paper, a double pendulum is analyzed with two subharmonic frequencies and in the main resonance zone. The results found demonstrate high similarities of the double pendulum with the parametric pendulum when compared the bifurcation diagrams based on varying the amplitude. The conditions in the numerical simulation include a variation in the viscous friction in the joints and different amplitudes and frequency of excitation. The differential equations used dimensionless parameters representing time, frequency, amplitude, friction, position and velocities. Concerning the results, all tests performed have pointed that the same type of motion takes place in the two pendulums after the transient time have already elapsed.
Negative energy enhancement in layered holographic conformal field theories
Authors: May Alex , Simidzija Petar , Van Raamsdonk Mark
Published: August 2021

Abstract

Using a holographic model, we study quantum field theories with a layer of one CFT surrounded by another CFT, on either a periodic or an infinite direction. We study the vacuum energy density in each CFT as a function of the central charges, the thickness of the layer(s), and the properties of the interfaces between the CFTs. The dual spacetimes in the holographic model include two regions separated by a dynamical interface with some tension. For two or more spatial dimensions, we find that a layer of CFT with more degrees of freedom than the surrounding one can have an anomalously large negative vacuum energy density for certain types of interfaces. The negative energy density (or null-energy density in the direction perpendicular to the interface) becomes arbitrarily large for fixed layer width when the tension of the bulk interface approaches a lower critical value. We argue that in cases where we have large negative energy density, we also have an anomalously high transition temperature to the high-temperature thermal state.
Duality-invariant extensions of Einstein-Maxwell theory
Authors: Cano Pablo A. , Murcia Ángel
Published: August 2021

Abstract

We investigate higher-derivative extensions of Einstein-Maxwell theory that are invariant under electromagnetic duality rotations, allowing for non-minimal couplings between gravity and the gauge field. Working in a derivative expansion of the action, we characterize the Lagrangians giving rise to duality-invariant theories up to the eight-derivative level, providing the complete list of operators that one needs to include in the action. We also characterize the set of duality-invariant theories whose action is quadratic in the Maxwell field strength but which are non-minimally coupled to the curvature. Then we explore the effect of field redefinitions and we show that, to six derivatives, the most general duality-preserving theory can be mapped to Maxwell theory minimally coupled to a higher-derivative gravity containing only four non-topological higher-order operators. We conjecture that this is a general phenomenon at all orders, i.e., that any duality-invariant extension of Einstein-Maxwell theory is perturbatively equivalent to a higher-derivative gravity minimally coupled to Maxwell theory. Finally, we study charged black hole solutions in the six-derivative theory and we investigate additional constraints on the couplings motivated by the weak gravity conjecture.
Target space entanglement in quantum mechanics of fermions and matrices
Authors: Sugishita Sotaro
Published: August 2021

Abstract

We consider entanglement of first-quantized identical particles by adopting an algebraic approach. In particular, we investigate fermions whose wave functions are given by the Slater determinants, as for singlet sectors of one-matrix models. We show that the upper bounds of the general Rényi entropies are N log 2 for N particles or an N × N matrix. We compute the target space entanglement entropy and the mutual information in a free one-matrix model. We confirm the area law: the single-interval entropy for the ground state scales as $$ \frac{1}{3} $$

1
3

log N in the large N model. We obtain an analytical $$ \mathcal{O}\left({N}^0\right) $$
O

N
0

expression of the mutual information for two intervals in the large N expansion.
Transcriptome programs involved in the development and structure of the cerebellum
Authors: Farini Donatella , Marazziti Daniela , Geloso Maria Concetta , Sette Claudio
Published: August 2021

In the past two decades, mounting evidence has modified the classical view of the cerebellum as a brain region specifically involved in the modulation of motor functions. Indeed, clinical studies and engineered mouse models have highlighted cerebellar circuits implicated in cognitive functions and behavior. Furthermore, it is now clear that insults occurring in specific time windows of cerebellar development can affect cognitive performance later in life and are associated with neurological syndromes, such as Autism Spectrum Disorder. Despite its almost homogenous cytoarchitecture, how cerebellar circuits form and function is not completely elucidated yet. Notably, the apparently simple neuronal organization of the cerebellum, in which Purkinje cells represent the only output, hides an elevated functional diversity even within the same neuronal population. Such complexity is the result of the integration of intrinsic morphogenetic programs and extracellular cues from the surrounding environment, which impact on the regulation of the transcriptome of cerebellar neurons. In this review, we briefly summarize key features of the development and structure of the cerebellum before focusing on the pathways involved in the acquisition of the cerebellar neuron identity. We focus on gene expression and mRNA processing programs, including mRNA methylation, trafficking and splicing, that are set in motion during cerebellar development and participate to its physiology. These programs are likely to add new layers of complexity and versatility that are fundamental for the adaptability of cerebellar neurons.
Semicontinuity of Gauss maps and the Schottky problem
Authors: Codogni Giulio , Krämer Thomas
Published: August 2021

We show that the degree of Gauss maps on abelian varieties is semicontinuous in families, and we study its jump loci. As an application we obtain that in the case of theta divisors this degree answers the Schottky problem. Our proof computes the degree of Gauss maps by specialization of Lagrangian cycles on the cotangent bundle. We also get similar results for the intersection cohomology of varieties with a finite morphism to an abelian variety; it follows that many components of Andreotti–Mayer loci, including the Schottky locus, are part of the stratification of the moduli space of ppav’s defined by the topological type of the theta divisor.
Preclinical evaluation of (S)-[18F]GE387, a novel 18-kDa translocator protein (TSPO) PET radioligand with low binding sensitivity to human polymorphism rs6971
Authors: Ramakrishnan Nisha K. , Hird Matthew , Thompson Stephen , Williamson David J. , Qiao Luxi , Owen David R. , Brooks Allen F. , Scott Peter J. H. , Bacallado Sergio , O’Brien John T. , Aigbirhio Franklin I.
Published: August 2021

Purpose

Positron emission tomography (PET) studies with radioligands for 18-kDa translocator protein (TSPO) have been instrumental in increasing our understanding of the complex role neuroinflammation plays in disorders affecting the brain. However, (R)-[11C]PK11195, the first and most widely used TSPO radioligand has limitations, while the next-generation TSPO radioligands have suffered from high interindividual variability in binding due to a genetic polymorphism in the TSPO gene (rs6971). Herein, we present the biological evaluation of the two enantiomers of [18F]GE387, which we have previously shown to have low sensitivity to this polymorphism.

Methods

Dynamic PET scans were conducted in male Wistar rats and female rhesus macaques to investigate the in vivo behaviour of (S)-[18F]GE387 and (R)-[18F]GE387. The specific binding of (S)-[18F]GE387 to TSPO was investigated by pre-treatment with (R)-PK11195. (S)-[18F]GE387 was further evaluated in a rat model of lipopolysaccharide (LPS)-induced neuroinflammation. Sensitivity to polymorphism of (S)-GE387 was evaluated in genotyped human brain tissue.

Results

(S)-[18F]GE387 and (R)-[18F]GE387 entered the brain in both rats and rhesus macaques. (R)-PK11195 blocked the uptake of (S)-[18F]GE387 in healthy olfactory bulb and peripheral tissues constitutively expressing TSPO. A 2.7-fold higher uptake of (S)-[18F]GE387 was found in the inflamed striatum of LPS-treated rodents. In genotyped human brain tissue, (S)-GE387 was shown to bind similarly in low affinity binders (LABs) and high affinity binders (HABs) with a LAB to HAB ratio of 1.8.

Conclusion

We established that (S)-[18F]GE387 has favourable kinetics in healthy rats and non-human primates and that it can distinguish inflamed from normal brain regions in the LPS model of neuroinflammation. Crucially, we have reconfirmed its low sensitivity to the TSPO polymorphism on genotyped human brain tissue. Based on these factors, we conclude that (S)-[18F]GE387 warrants further evaluation with studies on human subjects to assess its suitability as a TSPO PET radioligand for assessing neuroinflammation.
Further research on the clinical relevance of the ulcerative colitis colonoscopic index of severity for predicting 5-year relapse
Authors: Ishida Natsuki , Onoue Shunya , Miyazu Takahiro , Tamura Satoshi , Tani Shinya , Yamade Mihoko , Iwaizumi Moriya , Hamaya Yasushi , Osawa Satoshi , Furuta Takahisa , Sugimoto Ken
Published: August 2021

Purpose

The ulcerative colitis colonoscopic index of severity (UCCIS) evaluates the state of the entire colonic mucosa in ulcerative colitis. However, no cut-off values of scores for predicting clinical relapse in patients with ulcerative colitis have been established. This study aimed to determine the cut-off values for predicting clinical relapse in patients with ulcerative colitis.

Methods

The endoscopic scores (sum of Mayo endoscopic subscores (S-MES) and UCCIS) of 157 patients with ulcerative colitis experiencing clinical remission and their subsequent clinical course were retrospectively reviewed. The optimal cut-off values for predicting relapse and relapse-free rates were analyzed by receiver operating characteristic analysis.

Results

Forty patients with ulcerative colitis experienced relapse within 24 months. The median UCCIS for these patients at the time of study enrollment was significantly higher than that for patients with clinical remission (P < 0.001). The cut-off value of the UCCIS for predicting relapse was 9.8. The relapse-free rate was significantly lower in patients with UCCIS ≥ 9.8 than in those with UCCIS < 9.8 (log-rank test P < 0.001). For patients who experienced relapse within 5 years, the optimal cut-off values for the UCCIS and S-MES were 10.2 and 1, respectively (P = 0.004).

Conclusions

The data from this study indicate that the USSIC is a more relevant score than the S-MES for predicting the time to relapse in patients with ulcerative colitis in remission.
Fixation stability and implant-associated complications in periacetabular osteotomy: a comparison of screw and K-wire fixation
Authors: Leopold Vincent Justus , Conrad Juana , Zahn Robert Karl , Hipfl Christian , Perka Carsten , Hardt Sebastian
Published: August 2021

Aims

The aim of this study was to compare the fixation stability and complications in patients undergoing periacetabular osteotomy (PAO) with either K-wire or screw fixation.

Patients and methods

We performed a retrospective study to analyze a consecutive series of patients who underwent PAO with either screw or K-wire fixation. Patients who were treated for acetabular retroversion or had previous surgery on the ipsilateral hip joint were excluded. 172 patients (191 hips: 99 K-wire/92 screw fixation) were included. The mean age at the time of PAO was 29.3 years (16–48) in the K-wire group and 27.3 (15–45) in the screw group and 83.9% were female. Clinical parameters including duration of surgery, minor complications (soft tissue irritation and implant migration) and major complications (implant failure and non-union) were evaluated. Radiological parameters including LCE, TA and FHEI were measured preoperatively, postoperatively and at 3-months follow-up.

Results

Duration of surgery was significantly reduced in the K-wire group with 88.2 min (53–202) compared to the screw group with 119.7 min (50–261) (p < 0.001). Soft tissue irritation occurred significantly more often in the K-wire group (72/99) than in the screw group (36/92) (p < 0.001). No group showed significantly more implant migration than the other. No major complications were observed in either group. Postoperative LCE, TA and FHEI were improved significantly in both groups for all parameters (p = < 0.0001). There was no significant difference for initial or final correction for the respective parameters between the two groups. Furthermore, no significant difference in loss of correction was observed between the two groups for the respective parameters.

Conclusion

K-wire fixation is a viable and safe option for fragment fixation in PAO with similar stability and complication rates as screw fixation. An advantage of the method is the significantly reduced operative time. A disadvantage is the significantly higher rate of implant-associated soft tissue irritation, necessitating implant removal.

Level of evidence

III, retrospective trial.
Awareness of obstetricians for long-term risks in women with a history of preeclampsia or HELLP syndrome
Authors: Palmrich Pilar , Binder Carina , Zeisler Harald , Kroyer Bettina , Pateisky Petra , Binder Julia
Published: August 2021

Purpose

Hypertensive disorders of pregnancy are still a leading cause of maternal and neonatal morbidity and mortality worldwide. Women with a history of preeclampsia have an increased risk for future cardiovascular and cerebrovascular disease, renal disease as well as diabetes mellitus. There is little knowledge on postpartum risk management. The aim of this study was to assess follow-up care for patients after pre-eclampsia or HELLP syndrome.

Methods

This questionnaire-based cross-sectional study aimed to evaluate the current recommendations of obstetricians in Austria regarding follow-up care, long-term risk counselling and risk of recurrence in future pregnancies after preeclampsia or HELLP syndrome. Data were collected using a survey, based on recommendations given by three substantial guidelines on hypertensive disorders of pregnancy, which was distributed via e-mail to 69 public obstetric departments in Austria. Each obstetric department was required to answer one questionnaire per local protocol.

Results

Our results revealed that of the 48 participating hospitals most obstetricians are aware of the importance of follow-up care for women after a pregnancy complicated by preeclampsia. Our data show that most physicians counselled patients about the future cardiovascular health risks associated with preeclampsia or HELLP syndrome (79.2%). Most obstetricians recommended lifestyle modification (77.1%) and continued blood pressure measurements (97.9%). All centers stated to counsel about the risk of recurrence (100%). However, counselling regarding follow-up care to exclude kidney damage (37.5%) and underlying diseases like thrombophilia (39.6%) were less prioritized.

Conclusions

We were able to show that counselling concerning the risk of long-term cardiovascular disease and risk of recurrence after a pregnancy complicated by preeclampsia or HELLP syndrome has been established in obstetric departments in public hospitals. Regarding the evaluation of underlying chronic diseases such as thrombophilia or renal disease, as well as counselling on the future risk of renal disease is still improvable according to our data. Further evaluation of follow-up care after hypertensive disorders of pregnancy in the outpatient and private sector and implementation of structured guidelines for follow-up, as well as screening for cardiovascular disease are necessary to ensure adequate risk management and to provide opportunities for prevention.
Risk of pain in the neck and shoulders and job change among hairdressers: a combined questionnaire and register-based Danish prospective cohort study
Authors: Aavang Petersen Jonathan , Brauer Charlotte , Thygesen Lau Caspar , Flachs Esben Meulengracht , Bach Lund Christina , Froelund Thomsen Jane
Published: August 2021

Objective

To investigate whether intensity of work as a hairdresser was associated with treatments for pain, and if musculoskeletal pain was associated with leaving the hairdressing trade.

Methods

We formed two cohorts of hairdressers covered in the PensionDanmark Health Scheme (PDHS). Cohort 1 consisted of 1304 active hairdressers in 2009. Self-reported weekly haircuts were used as work intensity measure and treatments for pain in the neck and shoulders in PDHS were used as outcome. We used a Cox regression model with robust sandwich estimates adjusted for age, sex, employment status and prior treatment < 1 year before July 2009. Cohort 2 consisted of all hairdressers ever covered in the PDHS from 2006 to 2016 (n = 11,162). Exposure were treatments in PDHS within the last year. Outcome was leaving the trade within the following year. Adjustments were made for sex, calendar-year and age in Cox regression models.

Results

The adjusted hazard ratio of treatments in PDHS compared to the lowest work intensity was 0.95 (95% CI 0.58–1.55) and 0.74 (0.43–1.29) for medium and highest intensity, respectively. The risk of leaving the trade was lower, HR 0.80 (0.72–0.90) among hairdressers with treatments in PDHS within the last year, mainly driven by hairdressers aged < 56 years.

Conclusion

We found no association between intensity of work as a hairdresser, measured as self-reported weekly haircuts, and treatments for pain in PDHS. Furthermore, we found a protective effect of treatments in the PDHS within the last year on risk of leaving the trade.