bluuebunny/crossref_metadata_2025 huggingface dataset:
Photoinduced Activation of Unactivated C(sp3)‐H Bonds and Acylation Reactions
Authors: Ren Chen‐Chao , Wang Tian‐Qi , Zhang Yu , Peng Dao , Liu Xiao‐Qing , Wu Qing‐An , Liu Xue‐Fen , Luo Shu‐Ping
Published: March 2021

An efficient and benign method of C (sp3)‐H acylation based on the direct conversion of stable amides has been established. This photoredox cross‐coupling of amides and methylbenzenes for aromatic ketones is enabled by the cheap benzophenone photocatalyst and nickel catalyst, with high yield (up to 90 %). The benzophenone catalyst having electron‐withdrawing group promotes the efficiency of hydrogen atom transfer, which is beneficial to improve the yield.
Elliptic Calabi-Yau fivefolds and 2d (0,2) F-theory landscape
Authors: Tian Jiahua , Wang Yi-Nan
Published: March 2021

Abstract

In this paper, we initiate the study of the 2d F-theory landscape based on compact elliptic Calabi-Yau fivefolds. In particular, we determine the boundary models of the landscape using Calabi-Yau fivefolds with the largest known Hodge numbers h1,1 and h4,1. The former gives rise to the largest geometric gauge group in the currently known 2d (0,2) supergravity landscape, which is $$ {E}_8^{482\;632\;421}\times {F}_4^{3\;224\;195\;728}\times {G}_2^{11\;927\;989\;964}\times \mathrm{SU}{(2)}^{25\;625\;222\;180} $$

E
8

482

632

421

×

F
4

3

224

195

728

×

G
2

11

927

989

964

×
SU

2

25

625

222

180

. Besides that, we systematically study the hypersurfaces in weighted projective spaces with small degrees, and check the gravitational anomaly cancellation. Moreover, we also initiate the study of singular bases in 2d F-theory. We find that orbifold singularities on the base fourfold have non-zero contributions to the gravitational anomaly.
Tachyon condensation in magnetic compactifications
Authors: Buchmuller Wilfried , Dudas Emilian , Tatsuta Yoshiyuki
Published: March 2021

Abstract

Intersecting D-brane models and their T-dual magnetic compactifications provide an attractive framework for particle physics, allowing for chiral fermions and supersymmetry breaking. Generically, magnetic compactifications have tachyons that are usually removed by Wilson lines. However, quantum corrections prevent local minima for Wilson lines. We therefore study tachyon condensation in the simplest case, the magnetic compactification of type I string theory on a torus to eight dimensions. We find that tachyon condensation restores supersymmetry, which is broken by the magnetic flux, and we compute the Kaluza-Klein mass spectrum. The gauge group SO(32) is broken to USp(16). We give arguments that the vacuum reached by tachyon condensation corresponds to the unique 8d superstring theory already known in the literature, with discreteBabbackground or, in the T-dual version, the type IIB orientifold with three O7−-planes, one O7+-plane and eight D7-branes coincident with the O7+-plane. The ground state after tachyon condensation is supersymmetric and has no chiral fermions.
Statistics on Lefschetz thimbles: Bell/Leggett-Garg inequalities and the classical-statistical approximation
Authors: Millington Peter , Mou Zong-Gang , Saffin Paul M. , Tranberg Anders
Published: March 2021

Abstract

Inspired by Lefschetz thimble theory, we treat Quantum Field Theory as a statistical theory with a complex Probability Distribution Function (PDF). Such complex-valued PDFs permit the violation of Bell-type inequalities, which cannot be violated by a real-valued, non-negative PDF. In this paper, we consider the Classical-Statistical approximation in the context of Bell-type inequalities, viz. the familiar (spatial) Bell inequalities and the temporal Leggett-Garg inequalities. We show that the Classical-Statistical approximation does not violate temporal Bell-type inequalities, even though it is in some sense exact for a free theory, whereas the full quantum theory does. We explain the origin of this discrepancy, and point out the key difference between the spatial and temporal Bell-type inequalities. We comment on the import of this work for applications of the Classical-Statistical approximation.
Aspects of quantum information in finite density field theory
Authors: Daguerre Lucas , Medina Raimel , Solís Mario , Torroba Gonzalo
Published: March 2021

Abstract

We study different aspects of quantum field theory at finite density using methods from quantum information theory. For simplicity we focus on massive Dirac fermions with nonzero chemical potential, and work in 1 + 1 space-time dimensions. Using the entanglement entropy on an interval, we construct an entropic c-function that is finite. Unlike what happens in Lorentz-invariant theories, this c-function exhibits a strong violation of monotonicity; it also encodes the creation of long-range entanglement from the Fermi surface. Motivated by previous works on lattice models, we next calculate numerically the Renyi entropies and find Friedel-type oscillations; these are understood in terms of a defect operator product expansion. Furthermore, we consider the mutual information as a measure of correlation functions between different regions. Using a long-distance expansion previously developed by Cardy, we argue that the mutual information detects Fermi surface correlations already at leading order in the expansion. We also analyze the relative entropy and its Renyi generalizations in order to distinguish states with different charge and/or mass. In particular, we show that states in different superselection sectors give rise to a super-extensive behavior in the relative entropy. Finally, we discuss possible extensions to interacting theories, and argue for the relevance of some of these measures for probing non-Fermi liquids.
Function Theories in Cayley-Dickson Algebras and Number Theory
Authors: Kraußhar Rolf Sören
Published: March 2021

In the recent years a lot of effort has been made to extend the theory of hyperholomorphic functions from the setting of associative Clifford algebras to non-associative Cayley-Dickson algebras, starting with the octonions.

An important question is whether there appear really essentially different features in the treatment with Cayley-Dickson algebras that cannot be handled in the Clifford analysis setting. Here we give one concrete example: Cayley-Dickson algebras admit the construction of direct analogues of so-called CM-lattices, in particular, lattices that are closed under multiplication.

Canonical examples are lattices with components from the algebraic number fields$$\mathbb{Q}{[\sqrt{m1}, \ldots \sqrt{mk}]}$$Q[m1,…mk]. Note that the multiplication of two non-integer lattice paravectors does not give anymore a lattice paravector in the Clifford algebra. In this paper we exploit the tools of octonionic function theory to set up an algebraic relation between different octonionic generalized elliptic functions which give rise to octonionic elliptic curves. We present explicit formulas for the trace of the octonionic CM-division values.
Chondrocalcinosis does not affect functional outcome and prosthesis survival in patients after total or unicompartmental knee arthroplasty: a systematic review
Authors: Moret Céline S. , Iordache Edna , D’Ambrosi Riccardo , Hirschmann Michael T.
Published: March 2021

Purpose

There are contentious data about the role calcium pyrophosphate (CPP) crystals and chondrocalcinosis (CC) play in the progression of osteoarthritis (OA), as well as in the outcomes after knee arthroplasty. Hence, the purpose of this systematic review was to analyse the clinical and functional outcome, progression of OA and prosthesis survivorship after unicompartmental knee arthroplasty (UKA) and total knee arthroplasty (TKA) in patients with CC compared to patients without CC.

Methods

A systematic review of the literature in PubMed, Medline, Embase and Web of Science was performed using the “Preferred Reporting Items for Systematic Reviews and Meta-Analysis” (PRISMA) guidelines. Articles which reported the outcome and survival rates of prosthesis after TKA or UKA in patients with CC were included.

Results

A total of 3718 patient knees were included in eight selected publications, with a median sample sizes of 234 knees (range 78–1000) and 954 knees (range 408–1500) for publications including UKA and TKA, respectively. At time of surgery, the mean age was 69 years and the prevalence for CC ranged from 12.6 to 36%. Chondrocalcinosis did not significantly influence the functional and clinical outcome, the implant survival as well as the radiologic progression of OA disease after UKA and TKA.

Conclusion

The presence of CPP crystals in tissue samples, synovial fluid or evidence of calcifications on preoperative radiographs did not significantly influence the postoperative functional and activity scores. It also had no significant influence on prosthesis survival rate, whether it was a UKA or a TKA. This study shows that the impact of a subclinical form of chondrocalcinosis may not be of clinical relevance in the context of arthroplasty.

Level of evidence

IV.
An unusual case of late hematoma after implant-based breast reconstruction mimicking an anaplastic large cell lymphoma: a case report and literature review
Authors: Fioramonti Paolo , Lovero Stefano , Kaciulyte Juste , Ribuffo Diego , Frattaroli Jacopo M.
Published: March 2021

Late hematoma associated with breast implants used in esthetic and reconstructive breast surgery represents a rare entity. These hematomas do not have a clear etiology, but triggering events like trauma, anticoagulant use, capsule contracture, or chronic inflammation are reported in literature. We describe an 82-year-old patient who developed a unilateral intra-capsular hematoma 19 years after mastectomy and breast reconstruction with McGhan 445 g implant. Differential diagnosis with anaplastic large cell lymphoma (ALCL) was considered and potential causes of hematoma were evaluated. Constant pressure forces on chest wall were defined as pathophysiological cause. A systematic literature review concerning late hematoma cases was carried out, focusing on late hematoma etiology and various surgical treatments.

Level of evidence: Level V, diagnostic study.
Efficacy and safety of intravenous immunoglobulins for the treatment of viral encephalitis: a systematic literature review
Authors: Wagner Judith N. , Leibetseder Annette , Troescher Anna , Panholzer Juergen , von Oertzen Tim J.
Published: March 2021

Background

For most viral encephalitides, therapy is merely supportive. Intravenous immunoglobulins (IVIG) have been used as a prophylactic and therapeutic approach. We conduct a systematic review on the safety and efficacy of IVIG in viral encephalitis.

Methods

We conducted a systematic review assessing PubMed, Cochrane Database, Biosis Previews and the ClinicalTrials.gov website to identify all reports on patients with viral encephalitis treated with IVIG as of May 31, 2019. The main outcomes assessed were therapeutic efficacy and safety. For an increased homogeneity of the population, atypical viral infections were excluded, as were reports on prophylactic IVIG use, intrathecal application of immunoglobulins, or use of antibody-enriched IVIG-preparations. Data were extracted from published studies. Descriptive statistics were used.

Results

We included a total of 44 studies (39 case reports). The case reports cover a total of 53 patients. Our search retrieved two prospective and three retrospective studies. These show heterogeneous results as to the efficacy of IVIG therapy. Only one study reports a significant association between IVIG-use and death (odds ratio 0.032; 95% confidence interval 0.0033–0.3024; p = 0.0027). None of the studies report significant differences in the number of serious adverse events.

Conclusion

Data on the efficacy of IVIG-therapy is heterogeneous. While it seems generally safe, evident superiority compared to supportive treatment has not been demonstrated so far. Future trials should also investigate the optimal dosing and timing of IVIG and their benefit in the immunosuppressed.
Methodology for the systematic design of conical plain bearings for use as main bearings in wind turbines
Authors: Rolink Amadeus , Jacobs Georg , Schröder Tim , Keller Dennis , Jakobs Timm , Bosse Dennis , Lang Jochen , Knoll Gunter
Published: March 2021

With the possibility to replace sliding segments on the tower without disassembling the drivetrain, the use of segmented plain bearings with conical sliding surfaces as main bearing in wind turbines has a great potential to reduce the maintenance costs and thus the levelized cost of energy (LCOE). Furthermore, the short axial design leads to lower investment costs. Since this design is totally new and no design guidelines are available so far, the objective of this paper is to investigate the influence of the geometric parameters on the hydrodynamic pressure distribution of the bearing. In this context a parameter screening is performed using a suitable test field according to Plackett and Burman in order to determine the most relevant parameters. With the help of the simulations carried out after this test field, correlations between the geometric parameters and the hydrodynamic pressure distribution are evaluated. To be able to quantitatively analyze the three-dimensional pressure distribution, several key values are defined in this paper that describe the pressure distribution. The content of this paper is part of a methodology with the goal of developing a design guideline for conical plain bearings.
On monotonicity and search strategies in face-based copositivity detection algorithms
Authors: G.-Tóth B. , Hendrix E. M. T. , Casado L. G.
Published: March 2021

Over the last decades, algorithms have been developed for checking copositivity of a matrix. Methods are based on several principles, such as spatial branch and bound, transformation to Mixed Integer Programming, implicit enumeration of KKT points or face-based search. Our research question focuses on exploiting the mathematical properties of the relative interior minima of the standard quadratic program (StQP) and monotonicity. We derive several theoretical properties related to convexity and monotonicity of the standard quadratic function over faces of the standard simplex. We illustrate with numerical instances up to 28 dimensions the use of monotonicity in face-based algorithms. The question is what traversal through the face graph of the standard simplex is more appropriate for which matrix instance; top down or bottom up approaches. This depends on the level of the face graph where the minimum of StQP can be found, which is related to the density of the so-called convexity graph.
A robust-heuristic optimization approach to a green supply chain design with consideration of assorted vehicle types and carbon policies under uncertainty
Authors: Homayouni Zahra , Pishvaee Mir Saman , Jahani Hamed , Ivanov Dmitry
Published: March 2021

Adoption of carbon regulation mechanisms facilitates an evolution toward green and sustainable supply chains followed by an increased complexity. Through the development and usage of a multi-choice goal programming model solved by an improved algorithm, this article investigates sustainability strategies for carbon regulations mechanisms. We first propose a sustainable logistics model that considers assorted vehicle types and gas emissions involved with product transportation. We then construct a bi-objective model that minimizes total cost as the first objective function and follows environmental considerations in the second one. With our novel robust-heuristic optimization approach, we seek to support the decision-makers in comparison and selection of carbon emission policies in supply chains in complex settings with assorted vehicle types, demand and economic uncertainty. We deploy our model in a case-study to evaluate and analyse two carbon reduction policies, i.e., carbon-tax and cap-and-trade policies. The results demonstrate that our robust-heuristic methodology can efficiently deal with demand and economic uncertainty, especially in large-scale problems. Our findings suggest that governmental incentives for a cap-and-trade policy would be more effective for supply chains in lowering pollution by investing in cleaner technologies and adopting greener practices.
Sensorless environment stiffness and interaction force estimation for impedance control tuning in robotized interaction tasks
Authors: Roveda Loris , Piga Dario
Published: March 2021

Industrial robots are increasingly used to perform tasks requiring an interaction with the surrounding environment (e.g., assembly tasks). Such environments are usually (partially) unknown to the robot, requiring the implemented controllers to suitably react to the established interaction. Standard controllers require force/torque measurements to close the loop. However, most of the industrial manipulators do not have embedded force/torque sensor(s) and such integration results in additional costs and implementation effort. To extend the use of compliant controllers to sensorless interaction control, a model-based methodology is presented in this paper. Relying on sensorless Cartesian impedance control, two Extended Kalman Filters (EKF) are proposed: an EKF for interaction force estimation and an EKF for environment stiffness estimation. Exploiting such estimations, a control architecture is proposed to implement a sensorless force loop (exploiting the provided estimated force) with adaptive Cartesian impedance control and coupling dynamics compensation (exploiting the provided estimated environment stiffness). The described approach has been validated in both simulations and experiments. A Franka EMIKA panda robot has been used. A probing task involving different materials (i.e., with different - unknown - stiffness properties) has been considered to show the capabilities of the developed EKFs (able to converge with limited errors) and control tuning (preserving stability). Additionally, a polishing-like task and an assembly task have been implemented to show the achieved performance of the proposed methodology.
Speeds of Sound in Methanol at Temperatures from 233.33 to 353.21 K at Pressures up to 20 MPa
Authors: Scholz Christian W. , Span Roland
Published: March 2021

We report experimental speeds of sound in methanol. Measurements were conducted at temperatures from 233 to 353 K with pressures up to 20 MPa using the double-path length pulse-echo technique. The relative expanded combined uncertainty (k = 2) in measurement was estimated to vary from 0.012 to 0.014%, considering contributions from temperature, pressure, path length calibration, pulse timing, and purity of the sample. Experimental speeds of sound gained in the scope of this work were compared with the equation of state by de Reuck and Craven, as well as with further data from literature.
The syntax and semantics of Swedish copular sentences: a comparative perspective
Authors: Djärv Kajsa
Published: March 2021

This paper investigates the (recent) case alternation in Swedish equative and predicational copular sentences (‘Cicero is Tully’, ‘Cicero is a nice guy’). A central contribution of the paper is showing that this alternation is an LF-phenomenon, contra Sigurðsson (in: Hartmann, Molnárfi (eds) Comparative studies in Germanic syntax: from Afrikaans to Zurich German. John Benjamins Publishing Company, Amsterdam, 2006) who conjectures that Swedish is changing in the direction of English and Danish, where all postcopular DPs receive Accusative case, regardless of interpretation. The Swedish alternation is shown to track the same semantic dimension that conditions the choice of predicate case in languages like Polish, Russian and Dutch, namely the distinction between stage and individual level predication. Interestingly, the Swedish alternation is also shown to share distributional properties with the predicate case alternations in these languages. To account for these observations, I propose that the morphological and semantic contrasts between the two alternants are mediated by a structural difference, such that Nominative case involves a biclausal structure, and Accusative a monoclausal structure. This paper further adds to the typological picture, showing that Swedish patterns like Polish, Russian and Dutch, but unlike English and Danish, not just in terms of equative and predicational sentences, but also in specificational copular sentences (‘The fastest runner here is Lisa’). I argue that a particular kind of predicate inversion analysis is required to account for the Swedish type of specification.
Effects of Er:YAG laser irradiation of different titanium surfaces on osteoblast response
Authors: Wehner Christian , Laky Markus , Shokoohi-Tabrizi Hassan Ali , Behm Christian , Moritz Andreas , Rausch-Fan Xiaohui , Andrukhov Oleh
Published: March 2021

The aim of this in vitro study was to evaluate the effects of erbium-doped yttrium aluminum garnet (Er:YAG) laser irradiation on titanium surface topography and the proliferation and differentiation of osteoblasts using standard clinical treatment settings. Er:YAG laser irradiation at two levels ((1): 160 mJ, pulse at 20 Hz; (2): 80 mJ, pulse at 20 Hz) was applied to moderately rough and smooth titanium disks before MG-63 osteoblast-like cells were cultured on these surfaces. Titanium surface and cell morphology were observed by scanning electron microscopy. Cell proliferation/viability was measured by CCK-8 test. Gene expression of alkaline phosphatase (ALP), osteocalcin (OC), osteoprotegerin (OPG), receptor activator of nuclear factor kappa-B ligand (RANKL), and collagen type 1 was measured by qPCR, and OPG and OC protein production was determined by enzyme-linked immunosorbent assay. Treatment with Er:YAG laser at 160 mJ/20 Hz markedly caused heat-induced fusion of titanium and cell condensation on moderately rough surfaces, but not in smooth surfaces. MG-63 proliferation/viability decreased after 5 days in moderately rough surfaces. The expression of ALP, OC, OPG, and collagen type 1 was unaffected by laser treatment at 160 mJ/20. Laser irradiation at 80 mJ/20 Hz enhanced RANKL gene expression after 5 days in moderately rough surfaces. Study results suggest that Er:YAG laser irradiation at clinically relevant setting has no essential effect on osteogenic gene and protein expression of osteoblasts. However, surface structure, cell attachment, and proliferation are influenced by both treatment protocols, which implies that caution should be taken in the clinical treatment of peri-implant diseases when Er:YAG laser is used.
Improved healing of critical-size femoral defect in osteoporosis rat models using 3D elastin/polycaprolactone/nHA scaffold in combination with mesenchymal stem cells
Authors: Hejazi Fatemeh , Ebrahimi Vahid , Asgary Mehrdad , Piryaei Abbas , Fridoni Mohammad Javad , Kermani Ali Asghar , Zare Fatemeh , Abdollahifar Mohammad-Amin
Published: March 2021

Osteoporosis is a common bone disease that results in elevated risk of fracture, and delayed bone healing and impaired bone regeneration are implicated by this disease. In this study, Elastin/Polycaprolactone/nHA nanofibrous scaffold in combination with mesenchymal stem cells were used to regenerate bone defects. Cytotoxicity, cytocompatibility and cellular morphology were evaluated in vitro and observations revealed that an appropriate environment for cellular attachment, growth, migration, and proliferation is provided by this scaffold. At 3 months following ovariectomy (OVX), the rats were used as animal models with an induced critical size defect in the femur to evaluate the therapeutic potential of osteogenic differentiation of bone marrow mesenchymal stem cells (BM-MSCs) seeded on 3 dimension (3D) scaffolds. In this experimental study, 24 female Wistar rats were equally divided into three groups: Control, scaffold (non-seeded BM-MSC), and scaffold + cell (seeded BM-MSC) groups. 30 days after surgery, the right femur was removed, and underwent a stereological analysis and RNA extraction in order to examine the expression of Bmp-2 and Vegf genes. The results showed a significant increase in stereological parameters and expression of Bmp-2 and Vegf in scaffold and scaffold + cell groups compared to the control rats. The present study suggests that the use of the 3D Elastin/Polycaprolactone (PCL)/Nano hydroxyapatite (nHA) scaffold in combination with MSCs may improve the fracture regeneration and accelerates bone healing at the osteotomy site in rats.
SDF-1α gene-activated collagen scaffold enhances provasculogenic response in a coculture of human endothelial cells with human adipose-derived stromal cells
Authors: Laiva Ashang L. , O’Brien Fergal J. , Keogh Michael B.
Published: March 2021

Novel biomaterials can be used to provide a better environment for cross talk between vessel forming endothelial cells and wound healing instructor stem cells for tissue regeneration. This study seeks to investigate if a collagen scaffold containing a proangiogenic gene encoding for the chemokine stromal-derived factor-1 alpha (SDF-1α GAS) could be used to enhance functional responses in a coculture of human umbilical vein endothelial cells (HUVECs) and human adipose-derived stem/stromal cells (ADSCs). Functional responses were determined by (1) monitoring the amount of junctional adhesion molecule VE-cadherin released during 14 days culture, (2) expression of provasculogenic genes on the 14th day, and (3) the bioactivity of secreted factors on neurogenic human Schwann cells. When we compared our SDF-1α GAS with a gene-free scaffold, the results showed positive proangiogenic determination characterized by a transient yet controlled release of the VE-cadherin. On the 14th day, the coculture on the SDF-1α GAS showed enhanced maturation than its gene-free equivalent through the elevation of provasculogenic genes (SDF-1α—7.4-fold, CXCR4—1.5-fold, eNOS—1.5-fold). Furthermore, we also found that the coculture on SDF-1α GAS secretes bioactive factors that significantly (p < 0.01) enhanced human Schwann cells’ clustering to develop toward Bünger band-like structures. Conclusively, this study reports that SDF-1α GAS could be used to produce a bioactive vascularized construct through the enhancement of the cooperative effects between endothelial cells and ADSCs.
Coping Strategies and Subjective Well-being: Context Matters
Authors: Fischer Rabea , Scheunemann Jakob , Moritz Steffen
Published: March 2021

A growing body of research suggests that the functionality of coping strategies may in part depend on the context in which they are executed. Thus far, functionality has mostly been defined through the associations of coping strategies with psychopathology, particularly depression. Whether associations of coping strategies with proxies for happiness such as subjective well-being (SWB) are simply inverse remains to be shown. A total of n = 836 individuals from the U. S. general population participated in an online survey that included a revised version of the Maladaptive and Adaptive Coping Styles Questionnaire (MAX-R) that incorporates context-specific items, the Scale of Positive and Negative Affect (SPANE), the Temporal Satisfaction with Life Scale (TSWLS), the Patient Health Questionnaire (PHQ-9), and the Web Screening Questionnaire (WSQ). The MAX-R was submitted to an exploratory factor analysis. The factor analysis of the MAX-R yielded four subscales: adaptive, maladaptive, avoidance, and expressive suppression coping. Similar strategies in different contexts at times loaded on the same (e.g., maladaptive) or different (e.g., adaptive and avoidance) dimensions. Hierarchical multiple linear regression revealed significant associations of adaptive coping with SPANE (ß = 0.21), TSWLS (ß = 0.03), and PHQ-9 (ß = 0.07), all ps < .001, of maladaptive coping with SPANE (ß =  − 0.19), TSWLS (ß =  − 0.10), and PHQ-9 (ß = 0.02), all ps < .01, of avoidance with PHQ-9 (ß =  0.01, p < .001), and of expressive suppression with SPANE (ß =  − 0.06) and TSWLS (ß =  − 0.16), ps < .005. Final models explained 64.6% of variance in SPANE, 41.8% of variance in TSWLS, and 55% of variance in PHQ-9 score. In some instances, the functionality of coping strategies appears to be impacted by contextual factors. When investigating the overall benefit of use versus nonuse of coping strategies, their association with psychopathology measures and with subjective well-being should both be considered.
Twelve years of circulatory extracorporeal life support at the University Medical Centre Utrecht
Authors: Meuwese C. L. , Hermens J. A. , de Haan M. , Braithwaite S. A. , Ramjankhan F. , Buijsrogge M. P. , de Jonge N. , Kirkels J. H. , de Jong M. , Pasma W. , Vromen-Wijsman J. L. P. , Kraaijeveld A. O. , de Waal E. E. , Torn E. , Platenkamp M. , van der Heijden J. J. , Cremer O. L. , van Dijk D. , Donker D. W.
Published: March 2021

Introduction

Circulatory extracorporeal life support (ECLS) has been performed at the University Medical Centre Utrecht for 12 years. During this time, case mix, indications, ECLS set-ups and outcomes seem to have substantially changed. We set out to describe these characteristics and their evolution over time.

Methods

All patients receiving circulatory ECLS between 2007 and 2018 were retrospectively identified and divided into six groups according to a 2-year period of time corresponding to the date of ECLS initiation. General characteristics plus data pertaining to comorbidities, indications and technical details of ECLS commencement as well as in-hospital, 30-day, 1‑year and overall mortality were collected. Temporal trends in these characteristics were examined.

Results

A total of 347 circulatory ECLS runs were performed in 289 patients. The number of patients and ECLS runs increased from 8 till a maximum of 40 runs a year. The distribution of circulatory ECLS indications shifted from predominantly postcardiotomy to a wider set of indications. The proportion of peripheral insertions with or without application of left ventricular unloading techniques substantially increased, while in-hospital, 30-day, 1‑year and overall mortality decreased over time.

Conclusion

Circulatory ECLS was increasingly applied at the University Medical Centre Utrecht. Over time, indications as well as treatment goals broadened, and cannulation techniques shifted from central to mainly peripheral approaches. Meanwhile, weaning success increased and mortality rates diminished.
Accessing Mental Health Services: a Systematic Review and Meta-ethnography of the Experiences of South Asian Service Users in the UK
Authors: Prajapati Riddhi , Liebling Helen
Published: March 2021

Background

Despite calls to address ethnic inequalities to accessing mental health services in the UK, governmental initiatives have had limited impact. Studies indicate that South Asian communities underutilise mental health services. Previous reviews have identified cultural and institutional factors that may influence service use, but these are mostly narrative and limited in their scope.

Method

A systematic literature search resulted in fifteen studies exploring the experiences of seeking help and barriers to accessing and using services from the perspective of British South Asian service users.

Findings

Qualitative data was synthesised through meta-ethnography, and three themes emerged:Distanced from Services,Dilemma of TrustandThreat to Cultural Identity. South Asian service users were positioned at a distance from being able to access services and stuck in a dilemma of mistrusting White and Asian professionals. They constructed their cultural identity through a set of important values which were neglected by mental health services. Service users, therefore, appeared to engage in an ongoing evaluation of the potential benefits of accessing services against the risks of threat to their personal and cultural identities. The findings are discussed in relation to Eurocentric models of care and community engagement approaches.

Conclusion

The review argues that institutional racism and cultural dissonance marginalise South Asian service users from access to quality and effective mental healthcare. It is recommended that services acknowledge the impact of alienation and powerlessness and advance their practices to establish trust and cultural safety for South Asian service users in the UK.
Numerical Analysis WSGD Scheme for One- and Two-Dimensional Distributed Order Fractional Reaction–Diffusion Equation with Collocation Method via Fractional B-Spline
Authors: Ramezani Mohammad
Published: March 2021

The main propose of this paper is presenting an efficient numerical scheme to solve WSGD scheme for one- and two-dimensional distributed order fractional reaction–diffusion equation. The proposed method is based on fractional B-spline basics in collocation method which involve Caputo-type fractional derivatives for$$0 < \alpha < 1$$0<α<1. The most significant privilege of proposed method is efficient and quite accurate and it requires relatively less computational work. The solution of consideration problem is transmute to the solution of the linear system of algebraic equations which can be solved by a suitable numerical method. The finally, several numerical WSGD Scheme for one- and two-dimensional distributed order fractional reaction–diffusion equation.
One-step ball milling synthesis of VO2 (M) nanoparticles with exemplary thermochromic performance
Authors: Wang Chiyuan , Xu Huiyan , Liu Tongyao , Yang Shuaijun , Nie Yong , Wang Cheng , Guo Xiaodan , Wang Binbin , Ma Xin , Jiang Xuchuan
Published: March 2021

Vanadium dioxide (VO2) has demonstrated highly potential for smart windows because of its thermochromic property. This study represents the development of a facile but efficient method for the synthesis of VO2 (M) nanoparticles by ball milling method under ambient conditions, without release of waste liquid or gases. The key variables related to synthesis, including milling time and molar ratio of raw materials, have been investigated. It was found that the pure-phase VO2 (M) nanoparticles with the sizes of the particles ranged from 20 to 50 nm and relatively good dispersivity could be prepared by optimizing process parameters. For practice use to decrease the phase transition temperature, elemental W doping amount of 2 at.%, V1−xWxO2 (M) nanoparticles were also studied, and their glass coating exhibits high thermochromic performance with luminous transmittance (Tlum) of 44.18%, solar regulation efficiency (∆Tsol) of 9.64%, and the critical phase transition temperature (Tc) of ~ 42 °C. This work demonstrates a green and promising ball milling method to fabricate large scale VO2 (M) and V1−xWxO2 (M) nanoparticles for smart windows.
The plastic waste problem in Malaysia: management, recycling and disposal of local and global plastic waste
Authors: Chen Hui Ling , Nath Tapan Kumar , Chong Siewhui , Foo Vernon , Gibbins Chris , Lechner Alex M.
Published: March 2021

Plastic waste is one of the world’s most pressing human health and environmental concerns. Plastic constitutes the third highest waste source globally, with the total volume of plastic waste growing in-line with increases in the global population and per capita consumption. Malaysia is tracking global trends in both the overall generation of plastic waste and the consumption of single-use plastics and since 2017 has been the world’s largest importer of plastic waste. These elements create a number of major challenges for the country’s waste management system. This review outlines the current state of plastic waste production and management in Malaysia, including options for landfill, recycling and incineration. It presents information on the scale and both the human and ecological risks of plastic waste in the country (i.e. microplastics, landfill, incineration), outlines key plastic waste management policy initiatives (including plastics alternatives such as biodegradable plastics) and highlights key constraints on the success of these. Significant internal constraints stem from the inconsistent application of policy initiatives by state governments, in addition to the lack of public awareness and interest in household recycling. The paper closes by discussing options for and constraints on the switch to biodegradable alternatives and proposes a model of plastic management based on a circular economy approach and solid waste management hierarchy. Success in reducing the problems posed by plastic in Malaysia will require sustained effort at many levels, but positive experiences in other countries give some cause for optimism.
Numerical and perturbative analysis on non-axisymmetric Homann stagnation-point flow of Maxwell fluid
Authors: Sajid M. , Jagwal M. R. , Ahmad I.
Published: March 2021

In this paper, we examined the numerical and perturbative analysis of non-Newtonian fluid towards non-axisymmetric Homann stagnation-point flow. The Maxwell fluid model is applied to investigate the behavior of viscoelastic fluid for this particular geometry. The influence of Maxwell parameter $${\beta }_{1}$$

β
1

and ratio $$\gamma$$
γ
on different profiles are addressed in this analysis. The governed partial differential equations are reduced to ordinary differential equations with the help of similarity transformations. The numerical and perturbative outcomes of the resulting system of differential equations are obtained by applying the shooting technique. The solution is achieved for diverse values of relaxation time parameter $${\beta }_{1}$$

β
1

and ratio $$\gamma$$
γ
. The wall shear stress is compared to their large-$$\gamma$$
γ
asymptotic behaviors and displacement thicknesses are also presented. The numerical data for velocity profiles are obtained in terms of plots. It is predicted through analysis that a gradual increase in relaxation time raises wall skin friction components. On the other hand, velocity decreases which constitutes to reduce the reverse flow. Meanwhile, displacement thicknesses in $$x$$
x
and $$y$$
y
direction decreases. However, three-dimensional displacement thickness increases due to more viscoelastic material like Maxwell fluid than viscous fluid.
Numerical studies on the self-heating phenomenon of elastomers based on finite thermoviscoelasticity
Authors: Schröder Jonas , Lion Alexander , Johlitz Michael
Published: March 2021

Due to their typical material characteristics, elastomer components are used in almost all areas of engineering. In many cases, these components are subject to large cyclic deformations which result in hysteresis and dissipation-induced self-heating. Further they are exposed to varying ambient temperatures. Increased component temperatures can lead to the loss of a function or to total failure. Therefore, it is important to understand the causes and influences of critical temperatures and to identify them early in the development process under the condition of efficient applicability. In addition to the calculation time and accuracy, this also includes the experimental effort required to identify the material parameters and perform validation measurements. Within this work, the phenomenon of dissipative heating in elastomers is investigated in a numerical study using a modified model of the finite thermoviscoelasticity. For this purpose, a sufficiently simple material model was formulated and implemented under the assumption of the quasi-incompressible material behaviour. Based on this, the type and the characteristic features of the self-heating effect are specifically considered, and its dependence on thermal and mechanical initial and boundary conditions is studied. Thus, a new suitable parameter is introduced, which is particularly useful to identify critical loads. Analogously, the identification of dissipation-sensitive temperature ranges is presented. The utility of the general steadystate equilibrium condition as initial condition is also shown. Furthermore, the influence of the material properties on the steadystate equilibrium is demonstrated for the first time through parameter studies. Based on these findings, recommendations for modelling, calculation and experimental parameterisation are proposed.
Multichannel search patterns and webrooming behaviours in the service industries: the case of motor insurance
Authors: Hu Tun-I , Tracogna Andrea
Published: March 2021

This article aims at analysing the empirical categories and the main determinants of channel choices in the contractualized individual services category, with particular reference to multichannel search patterns and webrooming behaviours, whereby customers search online but purchase offline (namely, at the service provider’s premises). Based on an international survey of motor insurance customers, a set of hypotheses on the determinants of customers’ shopping journeys, inclusive of search and purchase channel decisions, have been tested with a multinomial logistic regression. Our results show that channel choices—both relative to search and to purchase—are significantly influenced by the customer’s preference for personal interaction (which typically favours the personal, offline, channels); overall, the relevance of channel choice determinants differs in the different shopping phases: indeed, while the search patterns (mono vs. multiple; digital vs. personal) are mainly determined by the customer need for information and by her/his preference for shopping innovation and enjoyment, the purchase channel choices are mainly driven by the customer’s preference for service quality (personal purchase) and by his/her price consciousness (digital purchase). In particular, webrooming behaviours occur when a less price-conscious customer, after having actively explored multiple channels to satisfy the appetite for information, eventually prefers to purchase the service at the provider’s physical store (i.e. the insurance agent) to satisfy his/her preference for personal interaction and service quality. These results shed light on multichannel behaviours in service industries and may help providers better inform the retail strategies of contractualized individual services.
Striatal dopamine D2/3 receptors in medication-naïve schizophrenia: an [123I] IBZM SPECT study
Authors: Chen Kao Chin , Yang Yen Kuang , Howes Oliver D. , Lee I Hui , Yeh Tzung Lieh , Chiu Nan Tsing , Chen Po See , David Anthony S. , Bramon Elvira
Published: March 2021

Background

The hyper-function of the striatal dopamine system has been suggested to underlie key pathophysiological mechanisms in schizophrenia. Moreover, patients have been observed to present a significant elevation of dopamine receptor availability compared to healthy controls. Although it is difficult to measure dopamine levels directly in humans, neurochemical imaging techniques such as single-photon emission computed tomography (SPECT) provide indirect indices of in vivo dopamine synthesis and release, and putative synaptic levels.

Methods

We focused on the role of dopamine postsynaptic regulation using [123I] iodobenzamide (IBZM) SPECT. We compared D2/3 receptor availability between 53 healthy controls and 21 medication-naive patients with recent-onset schizophrenia.

Result

The mean specific striatal binding showed no significant difference between patients and controls (estimated difference = 0.001; 95% CI −0.11 to 0.11; F = 0.00, df = 1, 69; p = 0.99). There was a highly significant effect of age whereby IBZM binding declined with advancing age [estimated change per decade of age = −0.01(binding ratio); 95% CI −0.01 to −0.004; F = 11.5, df = 1, 69; p = 0.001]. No significant correlations were found between the mean specific striatal binding and psychopathological or cognitive rating scores.

Conclusions

Medication-naïve patients with recent-onset schizophrenia have similar D2/3 receptor availability to healthy controls. We suggest that, rather than focusing exclusively on postsynaptic receptors, future treatments should target the presynaptic control of dopamine synthesis and release.
Beyond Identity: What Explains Hezbollah's Popularity among Non-Shi‘a Lebanese?
Authors: Karakoç Ekrem , Özcan Mesut , Alkan Özcan Sevinç
Published: March 2021

This study delves into how non-Shi‘a Lebanese assess Hezbollah and its activities. Having provided empirical evidence that Hezbollah has garnered positive perception in Lebanon, it asks what explains a substantial increase or decrease in favorable attitudes toward Hezbollah among Christians, Sunnis, and Druze? It argues that those who perceive Hezbollah as a resistance organization, as it often describes itself; the political alliance across sectarian groups; as well as insecurity caused by armed groups such as Sunni militant groups and ISIS, all combine to moderate people's views toward Hezbollah. Using an original, nationally representative face-to-face survey in Lebanon in 2015 and employing a multivariate statistical method, it finds that those who hold unfavorable views of the United States, those who support the political alliance of which Hezbollah is part, and those who support the Assad regime in Syria are likely to have a positive perception of Hezbollah and or its activities in the region.
A Transient in Surface Motions Dominated by Deep Afterslip Subsequent to a Shallow Supershear Earthquake: The 2018 Mw7.5 Palu Case
Authors: Nijholt N. , Simons W. J. F. , Efendi J. , Sarsito D. A. , Riva R. E. M.
Published: March 2021

The 2018 Palu earthquake is a remarkable strike‐slip event due to its nature as a shallow supershear fault rupture across several segments and a destructive tsunami that followed coseismic deformation. GPS offsets in the wake of the 2018 earthquake display a transient in the surface motions of northwest Sulawesi. A Bayesian approach identifies (predominantly aseismic) deep afterslip on and below the coseismic rupture plane as the dominant physical mechanism causing the cumulative, postseismic, surface displacements whereas viscous relaxation of the lower crust and poro‐elastic rebound contribute negligibly. We confirm a correlation between shallow supershear rupture and postseismic surface transients with afterslip activity in the zone below an interseismically locked fault plane where the slip rate tapers from zero to creeping.
The Mabja Dome Structure in Southern Tibet Revealed by Deep Seismic Reflection Data and Its Tectonic Implications
Authors: Li Hongqiang , Gao Rui , Li Wenhui , Carbonell Ramon , Yelisetti Subbarao , Huang Xingfu , Shi Zhuoxuan , Lu Zhanwu
Published: March 2021

The ongoing India‐Asia collision has led to the formation of the northern Himalayan gneiss domes belt in southern Tibet. The domes are the result of the ongoing convergence and were formed by geological processes that may include crustal thickening, metamorphism, partial melting, and exhumation of middle crustal rocks to the surface. A combination of compressional, extensional, and diapiric processes has been invoked to explain the formation and evolution of these domes. Differentiating among these competing hypotheses requires well‐defined geophysical images of the internal structure of the domes. The Mabja dome is the largest dome within the northern Himalayan gneiss domes belt. A 70‐km long deep seismic reflection profile across Mabja dome was acquired in 2016. The seismic data could provide new information about the structural elements beneath the domes to the depth of 25 Km. We address the structure of the Mabja dome by conducting an integrated analysis of shallow crustal velocity structure and a normal‐incidence seismic reflection image of deeper crust. Our work suggests that the Mabja dome is underlain by shear zones at depths of 10–15 km and two high‐velocity bodies at depths of 3 km possibly representing the eclogitic‐facies rocks or mafic intrusions. We propose that the dome formation may have been controlled by collision‐induced north‐south shortening expressed by thrust stacking of middle crustal rocks, which led to the doming of the upper‐crustal rocks. The proposed mechanism inferred for Mabja dome can be applied to interpret the widespread domes throughout the southern Tibet and other related structures in orogenic mountain belts.