bluuebunny/crossref_metadata_2025 huggingface dataset:
Post-COVID Education: Virtualization as the Way Forward
Authors: Ogadimma Emenyeonu C. , Raza Syed Hassan , Gorpe T. Serra , Irshad Farah
Published: July 2023

Online education has been in practice before COVID-19. However, COVID-19 pandemic has popularized online education. This study aims to explore the application of Process Virtualization Theory (PVT) in an e-learning process to gain new insights into the education context. Data was collected through an online survey from 362 university students in Pakistan. Results of the structural equational modeling indicate that eradication of digital divide can improve students’ engagement in virtual learning environments and thus entrench e-learning as a viable mode of education. Thus, this study has unfolded the understudied factor of digital divide in a developing country setting. To this end, the study underscored the threatening potential of digital divide to e-learning. Furthermore, the study has validated the notion of PVT theory that when a virtual process or a system reduces the need for sensory requirements, there are more chances of adoption. For educational institutions, the findings recommend incorporating offline learner-material and interaction capability (e.g., feedback) in their e-learning management system to promote students’ adoption of e-learning.
The Practices of Digital Citizenship Among Undergraduates at Sultan Qaboos University in Oman During COVID-19
Authors: Alsaadi Mouza , Alharassi Nabhan , Alsalmi Jamal , Alkindi Salim
Published: July 2023

Digital citizenship (DC) has been an essential subject in educational research for the last few years. This study aimed at discovering the degree to which Omani undergraduate students practiced digital citizenship during the COVID-19 pandemic. The participants were 262 undergraduate students (116 males and 164 females) who took an online university elective course at Sultan Qaboos University (SQU) in Spring of 2021. The study adopted a quantitative approach to data collection to investigate students’ digital citizenship practices. An online situational judgment test was developed and conducted to address six dimensions of digital citizenship: digital identity, digital civic engagement, digital ethics, digital literacy, digital safety, and global digital communication. The findings show that the level of practicing digital citizenship dimensions ranged from intermediate to low. Additionally, the results show that the least practiced dimensions are digital civic engagement and digital identity. Further, the results indicated some gender differences in students’ practices of digital citizenship. Considering the results, more efforts are required from stakeholders to enhance the level of DC among undergraduates. The findings of the study are considered good indicators to be taken when designing and evaluating curricula at higher education institutions.
Cybersecurity Awareness Among Students During the COVID-19 Digital Transformation of Education: A Case Study at the Muscat (Oman) Schools
Authors: Al Shabibi Ayida Mohammed , Al-Suqri Mohammed Nasser
Published: July 2023

The COVID-19 pandemic has developed numerous complicated challenges, and it has equally opened the door to another deadly force, known as cybercrime; many reports have indicated that cyberattacks have increased by 500% since the pandemic. While many awareness campaigns are conducted, these campaigns go through many challenges to develop effectiveness, cost coverage, and sustainability. Increasing public awareness of cybersecurity can be a critical strategy in preventing cybercrime or mitigating its impact at some level. Unfortunately, young people are an essential part of the community, and they are immature to recognize the dangers of these kinds of crimes to avoid being a target by cybercriminals. Therefore, the paper's viewpoint is to reform and update the education curricula through the following two objectives: discovering the consequences of COVID-19 on children's digital lives and generating information about current cybersecurity awareness levels among post-Basic education students in Muscat. The survey was conducted in early 2021 on 265 participants from six private schools. The results show that 83% of the students were exposed to cybersecurity incidents during the pandemic, and two-thirds think cybersecurity should be integrated into school curricula. However, awareness campaigns seem limited since 77% of students did not attend or hear about them.
Job Shadowing: An Evaluation of a Training Program for Enhancing the Communication Skills of Students During Covid-19 in Sharjah, UAE
Authors: Radwan Ahmed Farouk , Mousa Sheren Ali
Published: July 2023

This study aims to explore how the job shadowing program offered by the Sharjah government media bureau was experienced by communication and media students and professionals, and how it develops students’ skills and experience. The study also explores the impacts of the program during the Covid-19 period and the expectations from the program after the pandemic. The study works to help in creating effective training programs for media students with collaboration between universities and media organizations. A group discussion was conducted with 12 trainers and an online questionnaire was distributed to a sample of program attendees to monitor their viewpoints. 100 students responded to the survey. Results revealed that the job shadowing program has an effective role in developing students’ skills by enabling them to interact with professionals and benefiting from their experience. Students considered the program as an integrated way with the academic courses to support their practical skills. Results assured the need to design programs concerned with new topics, skills, and perspectives in media production to meet the needs of the media profession and academic requirements. Results revealed that coexistence and integration between academic programs and media institutions will be effective methods to develop the program.
Nonlinear Wind-Induced Vibration Behaviors of Multi-tower Suspension Bridges Under Strong Wind Conditions
Authors: Zhou R. , Ge Y. J. , Yang Y. , Du Y. D. , Zhang L. H.
Published: July 2023

The aerodynamic characteristics of a multispan suspension bridge differ from those of a two-span suspension bridge. In this study we investigated the nonlinear aerodynamic characteristics of the Maanshan Bridge under nonstationary flow using combination quasi-3D finite element (FE) bridge models of 2D nonlinear aerodynamic force models and 3D nonlinear FE bridge models. The developed model predictions were validated by wind tunnel tests involving a 2D sectional stiffness model and 3D full-bridge aeroelastic model. Results showed that the developed model could potentially describe the nonlinear and unsteady aerodynamic effects on the bridge. Furthermore, the flutter behavior of the Maanshan Bridge under uniform flow changed from the stable limit cycle of soft flutter to unstable limit cycle with the disconnection of two hangers at the 1/2L of the right main span, while the flutter behavior of the bridge under turbulence flow could be defined as the fracture failure of the hangers from the 1/2L of the left main span.
Role of Aggregate Reactivity, Binder Composition, and Curing Temperature on the Delayed Ettringite Formation and Associated Durability Loss in Concrete
Authors: Martin L. , Thomas P. , De Silva P. , Sirivivatnanon V.
Published: July 2023

The durability of concrete is critical to its worldwide use as a structural material for buildings and infrastructure, with the lifetime service of concrete greatly affecting its economic, environmental, and social costs. Causes of durability loss in some concrete structures can be attributed to the alkali–silica reaction (ASR) and delayed ettringite formation (DEF). Both are chemical reactions that have the potential to cause expansion and strength loss in affected elements. Significant overlap exists in the factors contributing to ASR and DEF in concrete structures, with widely reported evidence of deleterious DEF frequently occurring in conjunction with mild or moderate ASR. For precast concrete, experiments in mortars have provided limits in the alkali and sulfate content of the binder and maximum curing temperatures used to minimize DEF risk. The role of other constituents in concrete specimens, notably the aggregate, has been overlooked. We investigated the role of reactive aggregates and ASR in the susceptibility of concrete to deleterious DEF.
Partially-Unzipped Carbon Nanotubes as Low-Concentration Amendment for Cement Paste
Authors: Iffat S. , Matta F. , Gaillard J. , Elvington M. , Sikder M. , Baalousha M. , Tinkey S. , Meany J.
Published: July 2023

Partially-unzipped multiwalled carbon nanotubes (PUCNTs) combine the chemical structure and basic mechanical properties of multiwalled carbon nanotubes (MWCNTs) and graphene nanoplatelets (GNPs) with exceptionally high graphene-edge content. As a result, PUCNTs can be effectively oxidized for dispersion in aqueous solutions and have a specific surface area that is larger than that of MWCNTs with a comparable aspect ratio. Thus, the incorporation of relatively small concentrations of PUCNTs in cement composites may result in significant physicomechanical enhancements. In the proof-of-concept study presented here, cement paste specimens were manufactured with oxidized PUCNT concentrations of 0, 0.001, and 0.005% in weight of cement (wt%), that is, one order of magnitude smaller than lower-bound concentrations for MWCNTs reported in the literature. Stable dispersion in water was verified through dynamic light scattering analysis. Physicomechanical changes and PUCNT dispersion in the cement matrix were investigated through uniaxial compression tests on 25 × 25 × 76 mm prism specimens, and visual inspection of scanning electron microscopy (SEM) micrographs, respectively. The incorporation of 0.001 wt% and 0.005 wt% of PUCNTs resulted in an average increase in compressive strength of 10% and 29%, respectively, compared with plain cement paste. In both instances, representative SEM micrographs show the preferential formation of cement hydrates in cement paste that accorded with well-dispersed PUCNTs.
Effect of Fine Aggregates and Test Settings on the Self-sensing Response of Cement-Based Composites with Carbon Nanotubes as Conductive Filler
Authors: dos Santos T. C. , Carísio P. A. , Martins A. P. S. , Paiva M. D. M. , Gomes F. M. P. , Reales O. A. M. , Toledo Filho R. D.
Published: July 2023

Cement-based self-sensing composites with carbon nanotubes (CNT) have attracted attention due to their multifunctional properties and great potential for their application in the smart monitoring of concrete structures. In this study, the self-sensing properties of one paste and three mortars containing 0.50 and 0.75 wt% of CNT, and 1.5 and 1.0 sand/cement ratio were investigated, aiming to evaluate their impact on the piezoresistive response of the composites. The inclusion of sand in the cement paste with CNT led to a reduced gauge factor and a higher electrical noise response. The inert aggregates modified the compressive loading mechanical response of the composites and possibly acted as barriers to electronic mobility, by increasing the CNT conductive paths’ tortuosity or even interrupting them. The mortar containing 0.50% of CNT showed a higher electrical resistivity and, at the same time, greater sensitivity and a more linear self-sensing response than the one with 0.75% CNT, which can be explained by the CNT content being closer to its percolation threshold in the first. In this way, a lower CNT concentration generated a conductive network with a higher capacity to be rearranged under loading, generating significant changes in resistivity, but a higher CNT concentration presented a more stable and conductive network. The results suggested that both the conductive and non-conductive phases affect the detection performance of the composites and, therefore, must be dosed appropriately. Additionally, the test setup modifications positively affected the self-sensing response signal, which is particularly useful to reduce the deleterious effects of the sand additions in the matrix. This overall approach can make the use of self-sensing mortars in structural monitoring a viable option.
A New Dispersion Strategy to Achieve High Performance Graphene-Based Cement Material
Authors: Zhang Z. , Yao Y. , Liu H. , Zhuge Y. , Zhang D.
Published: July 2023

The addition of graphene and its derivatives can enhance the mechanical and functional properties of cement-based composites, but most of the current technologies have limited dispersion and are costly. The creation of a cost-effective graphene-reinforced cement material with uniform graphene dispersion remains difficult. We used glucose as an economical carbon source to induce the in-situ formation of graphene on cement particles. Our proposed method is approximately 80% less expensive than commercial techniques. Evaluation of the microscopic morphology demonstrated uniform distribution of graphene in the cement matrix, which improved the mechanical properties of the cement paste. The compressive strengths of the test groups with 3% carbon source improved by almostly 38% and 48.9%, respectively, compared with pure cement paste. This newly established technique is essential for the future design of excellent graphene-based cement materials and the achievement of multifunctional cementitious applications.
Co-effects of Graphene Oxide and Silica Fume on the Rheological Properties of Cement Paste
Authors: Lu D. , Sheng Z. , Yan B. , Jiang Z.
Published: July 2023

Polycarboxylate superplasticizer is typically used to prepare a high-quality graphene oxide (GO) solution before mixing with cement grains. However, even if GO is well dispersed in water, they tend to re-agglomerate in the alkaline cement hydration environment, thus seriously decreasing the workability of the fresh mixture. In this study, we propose a more targeted method by synthesizing GO-coated silica fume (SF) to promote the utilization of GO in cement-based materials. Specifically, the surface of pristine SF was modified to convert their zeta potential (modified SF: MSF), then GO-coated SF (i.e., MSF@GO) was prepared via electrostatic adsorption of GO onto the MSF surface. The experimental results revealed that adding 5MSF@GO hybrid (0.04% GO and 5% MSF, by weight of binder) significantly reduced yield stress and plastic viscosity by 51.5% and 26.2%, respectively, relative to the 0.04% GO-modified sample. These findings indicated that application of GO-coated SF is an effective and environmentally friendly way to develop sustainable cementitious composites.
Automated 3D-Printer Maintenance and Part Removal by Robotic Arms
Authors: Andrews K. , Granland K. , Chen Z. , Tang Y. , Chen C.
Published: July 2023

3D printing by means of fused filament fabrication involves extruding and depositing melted material in layers to produce a 3D part. Current 3D printing requires manual intervention from a human operator between prints, leading to inefficiency. The focus of this study was facilitating the automation of the additive manufacturing process. Based on suggestions for future works in this field, this study extended on automated 3D-part removal systems by implementing additional operations to automate the production process. The proposed system uses robotic arms and grippers to operate and maintain 3D printers; specifically, the removal of 3D-printed parts, the cleaning of printer beds, the application of glue to the printer beds to assist with print adhesion, and the monitoring of bed levelness. The importance of this contribution is the improved efficiency of 3D-printing production, allowing for continuous 3D-printer operation and decreasing the requirement for human interaction and monitoring in the production process. The system is demonstrated using a 7 degrees of freedom KUKA robotic arm and ROBOTIQ gripper to autonomously operate and maintain an Ender 3 V2 printer. Sensor data and information from the 3D printers was used to determine the required operation or function to be performed by the robotic system. Tasks were performed by automated movement sequences of the robotic arm and gripper using supplied data. System status was recorded for monitoring and alerting human operators when intervention was required. The implementation of these functions using an automated robotic system allows 3D-printing production to operate continuously for longer periods, increasing production efficiency as downtime and human involvement for maintenance between prints is minimized.
Electrical and Sulfate-Sensing Properties of Alkali-Activated Nanocomposites
Authors: Davoodabadi Maliheh , Liebscher Marco , Sgarzi Massimo , Riemenschneider Leif , Wolf Daniel , Hampel Silke , Cuniberti Gianaurelio , Mechtcherine Viktor
Published: July 2023

We investigated the formation of the conductive network of carbon nanotubes (CNTs) in alkali-activated nanocomposites for sulfate-sensing applications. The matrix was a one-part blend of fly ash and ground granulated blast-furnace slag, activated by sodium silicate and water. Sodium dodecylbenzenesulfonate was used as the surfactant for dispersion of the CNTs in the aqueous media. The nanocomposites were investigated by a laboratory-developed setup to study the electrical and sensing properties of the alkali-activated material. The electrical properties (i.e., conductivity) were calculated and assessed to discover the percolation threshold of the nanocomposites. Furthermore, the sensing behavior of nanocomposites was studied upon sulfate ($${\mathrm{SO}}_{4}^{2-}$$

SO

4

2
-

) exposure by introduction of sulfuric acid ($$({\mathrm{H}}_{2}{\mathrm{SO}}_{4})$$

(

H
2

SO
4

)

) and magnesium sulfate ($${\mathrm{MgSO}}_{4}$$

MgSO
4

). The sensors were able to preliminarily exhibit a signal difference based on the introduced media ($${\mathrm{H}}_{2}{\mathrm{SO}}_{4} \&\mathrm{ Mg}{\mathrm{SO}}_{4}$$

H
2

SO
4

&
Mg

SO
4

), CNT content and $${\mathrm{H}}_{2}{\mathrm{SO}}_{4}$$

H
2

SO
4

volumetric quantity. The results of this research demonstrated a sensing potential of CNT alkali-activated nanocomposites and can be applied in the concrete structural health monitoring.
Investigation on Superhydrophobicity and Piezoresistivity of Self-sensing Cement-Based Sensors Using Silane Surface Treatment
Authors: Dong W. K. , Li W. G. , Lin X. Q. , Shah S. P.
Published: July 2023

Cement-based sensors are highly susceptible to the effects of watery environments due to the hydrophilic properties of the cement matrix. In this paper, we applied a surface treatment using a silane/isopropanol solution to graphene/cement-based sensors to achieve superhydrophobicity and mitigate piezoresistive instability in watery environments. After treatment, impressive water contact angles of 163.4° and 142.0° were achieved for the surface and inner cement-based sensors, respectively. Moreover, the piezoresistivity of the coated cement-based sensors exhibited greater stability compared to their untreated counterparts. These results provide valuable insights into the piezoresistivity of hydrophobic cement-based sensors in moist environments, offering promising prospects for future structural health monitoring applications.
Roads Issues and the Social License to Operate
Authors: Young W. , Shackleton M.
Published: July 2023

Because it is agreed that the transport system needs the support and engagement of the public in its development and implementation, we explored the concept of the “social license to operate the road system” (SLORS) to show how it can assist in road policy and network implementation. We looked at 18 policy issues and identified their placement in a SLORS framework. The policy issues were categorized into 5 zones: User Advocacy Zone, Support Zone, Equilibrium Zone, Tolerance Zone and Opposition Zone. The relevant zone provides information to policy makers on the public’s view of the policy. For instance: in the Advocacy Zone issues such as Driver behavior should improve, Roads must be safe for all users, the Physical quality of the road and their surface should improve, and Road travel should be more environmentally sustainable in the future are supported—and should be relatively easy to implement. In the Opposition zone People paying a toll or road charge for each trip, Private companies having a large role in planning and management of roads, Increased congestion and Increased traffic on roads in the future receive less support and thus will require considerable effort marketing their implementation. SLORS may assist in pointing the policy maker in the best direction to get the policy supported.
Machine Learning-Aided Nonlinear Dynamic Analysis of Engineering Structures
Authors: Feng Y. , Wang Q. , Wu D. , Gao W.
Published: July 2023

A machine learning (ML) technique was used to assist in the dynamic analysis of mixed geometric and material nonlinearities of real-life engineering structures. Various types of inputs of system properties were considered in the 3D dynamic geometric elastoplastic analysis, giving a series of realistic nonlinear descriptions of complex, large deformation structural behaviors. To resolve the numerical challenges of solving the mixed nonlinear problems, a newly established ML technique using a new cluster-based extended support vector regression (X-SVR) algorithm was applied. With this technique, a surrogate model can be built at each time step in the Newmark time integration process, which can then be used to predict the deflection, force and stress of the relevant structural performance at different loading time stages. To demonstrate the accuracy and efficiency of the proposed framework, practical engineering applications with linear and nonlinear properties are fully demonstrated, and the nonlinear behavior of the structure under predicted working conditions in the future was predicted and verified in numerical studies.
Deterioration Modeling of Concrete Bridges and Potential Nanotechnology Application
Authors: Tran H. , Setunge S.
Published: July 2023

Management of aging concrete bridges with limited resources can be a challenge for state authorities. Deterioration modeling of concrete bridges at the component level is essential to optimize maintenance actions and ensure the safety and serviceability of the bridge network. In this study we examined the Level 2 visual inspection data of a concrete bridge’s components collected over 4–5 inspection cycles with the objective of predicting deterioration of components and the bridge’s life cycle. With the increasing application of nanotechnology to increase the mechanical properties and durability of concrete material for bridge structures, the deterioration of nano-based concrete could be significantly different from conventional concrete. A range of deterioration prediction methods, including deterministic models and stochastic models, were examined to understand the validity of the different methods in predicting the deterioration of bridge components made of conventional and nano-based materials. A case study with a demonstration on a concrete open girder was investigated with regard to linear regression models and the stochastic Markov deterioration model. The outcomes can be used to support future study on the performance of conventional and nano-based concrete materials and their lifecycles in the asset management of bridges.
A Novel Concrete Mix Design Methodology
Authors: Kumar D. , Alam M. , Sanjayan J.
Published: July 2023

Concrete mix design is the methodology for mixing binder, aggregate and water to achieve required physical, mechanical, and thermal properties. In particular, the physical properties depend on the volume fraction of each element in the concrete recipe. In this study we considered cement mortar, complying with ASTM C105, as the reference concrete with cement as the binder and silica sand as the aggregate. The reference mortar was denser with high thermal conductivity and compressive strength at given rheological properties. A denser concrete presents difficulty in material handling and imposes a safety risk, and high thermal conductivity increases building energy consumption. Therefore, lightweight concrete (LWC) has been developed by replacing silica sand with porous materials. LWC includes cement as the binder, with silica sand and other porous materials as the primary and binary fillers. The mass of the filler materials is determined by their particle density and volume fraction. LWC has low thermal mass, thereby exacerbating the summertime overheating and peak cooling demand of buildings. Therefore, there is a need to design a LWC with high thermal mass by incorporating phase change materials (PCM), which are mainly incorporated as tertiary filler. Here, we propose a novel concrete mix design methodology to incorporate PCM composite as a partial replacement of the porous material without changing binding materials.
Characterization of the Nano- and Microscale Deterioration Mechanism of the Alkali–Silica Reaction in Concrete Using Neutron and X-ray Scattering Techniques: A Review
Authors: Nsiah-Baafi E. , Tapas M. J. , Vessalas K. , Thomas P. , Sirivivatnanon V.
Published: July 2023

Alkali–silica reaction (ASR) is one of the most recognized chemical reactions that lead to the deterioration and premature failure of concrete. The severity of ASR is largely dependent on the expansive nature of the reaction product (ASR gel). As such, it is important to expound the developed knowledge on the formation, structure, composition, and swelling mechanism of ASR gel, to provide a greater understanding of ASR deterioration and to facilitate the development of more reliable prediction and mitigation methods. We present a summary of existing methods for assessing ASR and the state-of-the-art techniques that use neutron and X-ray scattering methods to characterize the nano- and microstructural properties of concrete and elucidate the potential transport dynamics of reactants that determine the mechanism and extent of ASR.
Harmonic Vibration of Inclined Porous Nanocomposite Beams
Authors: Chen D. , Zhang L.
Published: July 2023

This work investigated the linear harmonic vibration responses of inclined beams featured by closed-cell porous geometries where the bulk matrix materials were reinforced by graphene platelets as nanofillers. Graded and uniform porosity distributions combined with different nanofiller dispersion patterns were applied in the establishment of the constitutive relations, in order to identify their effects on beam behavior under various harmonic loading conditions. The inclined beam model comprised of multiple layers and its displacement field was constructed using Timoshenko theory. Forced vibration analysis was conducted to predict the time histories of mid-span deflections, considering varying geometrical and material characterizations. The findings may provide insights into the development of advanced inclined nanocomposite structural components under periodic excitations.
Influence of Carbon Nanotubes on the Fracture Surface Characteristics of Cementitious Composites Under the Brazilian Split Test
Authors: Gao Y. , Xiang J. , Yu Z. , Han G. , Jing H.
Published: July 2023

To better analyze the reinforcing mechanisms of carbon nanotubes (CNTs) in cementitious composites, the micromorphological characteristics of the fracture surface of cement-based specimens under the Brazilian split test were investigated. The results demonstrated that the addition of CNTs promoted nucleation and pore filling effects that optimized the pore structure and inhibited the development of microcracks in the cement matrix during loading. Due to the ultra-high specific surface area and bridging effects of CNTs, the formation of hydration products was promoted, internal microcracks and micropores were effectively reduced, and the regularity and integrity of the samples also improved. Therefore, under tensile loading, CNT-reinforced cementitious composites absorbed more energy, resulting in more complex stress paths and rougher fracture surfaces.
Behavior of Hybrid Engineered Cementitious Composites Containing Nanocellulose
Authors: Withana H. , Zhang Y. X.
Published: July 2023

Nanocellulose (NC) is a promising reinforcing material for cementitious composites, but its effect on the mechanical properties of hybrid engineered cementitious composites (ECCs) has not been studied. In this paper, we investigated a hybrid polyethylene (PE)-steel fibre ECC reinforced with NC and the effect of NC dosages ranging from 0.1% to 0.4% on the compressive strength of the hybrid ECC. The optimum quantity of NC for the best mechanical property of ECC was determined. Enhancement of compressive strength was observed for all the mixes with NC compared with the reference mix, and the mix containing 0.2% NC showed the maximum improvement.
Erratum to: An updated view on the ATOMKI nuclear anomalies
Authors: Barducci Daniele , Toni Claudio
Published: July 2023

A correction to this paper has been published: https://doi.org/10.1007/JHEP02(2023)154
Covariant bit threads
Authors: Headrick Matthew , Hubeny Veronika E.
Published: July 2023

Abstract

We derive several new reformulations of the Hubeny-Rangamani-Takayanagi covariant holographic entanglement entropy formula. These include: (1) a minimax formula, which involves finding a maximal-area achronal surface on a timelike hypersurface homologous to D(A) (the boundary causal domain of the region A whose entropy we are calculating) and minimizing over the hypersurface; (2) a max V-flow formula, in which we maximize the flux through D(A) of a divergenceless bulk 1-form V subject to an upper bound on its norm that is non-local in time; and (3) a min U-flow formula, in which we minimize the flux over a bulk Cauchy slice of a divergenceless timelike 1-form U subject to a lower bound on its norm that is non-local in space. The two flow formulas define convex programs and are related to each other by Lagrange duality. For each program, the optimal configurations dynamically find the HRT surface and the entanglement wedges of A and its complement. The V-flow formula is the covariant version of the Freedman-Headrick bit thread reformulation of the Ryu-Takayanagi formula. We also introduce a measure-theoretic concept of a “thread distribution”, and explain how Riemannian flows, V-flows, and U-flows can be expressed in terms of thread distributions.
Delaying ACL reconstruction is associated with increased rates of medial meniscal tear
Authors: Erard Julien , Cance Nicolas , Shatrov Jobe , Fournier Gaspard , Gunst Stanislas , Ciolli Gianluca , Porcelli Pasquale , Lustig Sébastien , Servien Elvire
Published: July 2023

Purpose

The aim of this study was to evaluate the relationship between the time from injury to ACL reconstruction (ACLR) and the rate as well as repairability of meniscal tears. Secondary aims were to evaluate the relationship between meniscal injury and Tegner Activity Scale, age, BMI, and gender.

Methods

Between 2012 and 2022, 1,840 consecutive ACLRs were performed. A total of 1,317 ACLRs were included with a mean patient age of 31.2 years ± 10.5 [16–60]. Meniscal tear was assessed during arthroscopy using the ISAKOS classification. Time from injury to ACLR, Tegner Activity Scale, age, BMI and gender were analysed in uni‐ and then in multivariate analyses. Patients were divided into four groups according to the time from injury to surgery: < 3 months (427; 32%), 3–6 months (388; 29%), 6–12 months (248; 19%) and > 12 months (254; 19%).

Results

Delaying ACLR > 12 months significantly increased the rate of medial meniscal (MM) injury (OR 1.14; p < 0.001). No correlation was found between a 3‐ or 6‐month time from injury to surgery and MM tear. Performing ACLR > 3, 6, or 12 months after injury did not significantly increase the rate of lateral meniscal (LM) injury. Increasing Tegner activity scale was significantly associated with a lower rate of MM injury (OR 0.90; p = 0.020). An age > 30 years (OR 1.07; p = 0.025) and male gender (OR 1.13; p < 0.0001) was also associated with an increased rate of MM injury. Age > 30 years decreased the rate of MM repair (OR 0.85; p < 0.001). Male gender increased the rate of LM tear (OR 1.10; p = 0.001).

Conclusion

Performing ACLR more than 12 months after injury was associated with increased rates of MM injury but not with lower rates of repairable lesions. An increased pre‐injury Tegner activity score was associated with a decreased rate of MM tear. Age > 30 years was associated with an increased rate of MM tear with concomitant ACL injury and a decreased rate of repairability of MM tear. ACLR should be performed within 12 months from injury to prevent from the risk of MM injury.

Level of Evidence

Level III.
Exact Morse index of radial solutions for semilinear elliptic equations with critical exponent on annuli
Authors: Miyamoto Yasuhito
Published: July 2023

Let $$N\ge 3$$

N
≥
3

, $$R>\rho >0$$

R
>
ρ
>
0

and $$A_{\rho }:=\{x\in \mathbb {R}^N;\ \rho<|x|<R\}$$

A
ρ

:
=
{
x
∈

R

N

;

ρ
<
|
x
|
<
R
}

. Let $$U^{\pm }_{n,\rho }$$

U

n
,
ρ

±

, $$n\ge 1$$

n
≥
1

, be a radial solution with n nodal domains of $$\begin{aligned} {\left\{ \begin{array}{ll} \Delta U+|x|^{\alpha }|U|^{p-1}U=0 &{} \text {in}\ A_{\rho },\\ U=0 &{} \text {on}\ \partial A_{\rho }. \end{array}\right. } \end{aligned}$$

Δ
U
+

|
x
|

α

|
U
|

p
-
1

U
=
0

in

A
ρ

,

U
=
0

on

∂

A
ρ

.

We show that if $$p=\frac{N+2+2\alpha }{N-2}$$

p
=

N
+
2
+
2
α

N
-
2

, $$\alpha >-2$$

α
>
-
2

and $$N\ge 3$$

N
≥
3

, then $$U^{\pm }_{n,\rho }$$

U

n
,
ρ

±

is nondegenerate for small $$\rho >0$$

ρ
>
0

and the Morse index $${{\textsf{m}}}(U^{\pm }_{n,\rho })$$

m
(

U

n
,
ρ

±

)

satisfies $$\begin{aligned} {{\textsf{m}}}(U^{\pm }_{n,\rho }) =n\frac{(N+2\ell -1)(N+\ell -1)!}{(N-1)!\ell !} \quad \text {for small}\ \rho >0, \end{aligned}$$

m

(

U

n
,
ρ

±

)

=
n

(
N
+
2
ℓ
-
1
)
(
N
+
ℓ
-
1
)
!

(
N
-
1
)
!
ℓ
!

for small

ρ
>
0
,

where $$\ell =[\frac{\alpha }{2}]+1$$

ℓ
=
[

α
2

]
+
1

. Using Jacobi elliptic functions, we show that if $$(p,\alpha )=(3,N-4)$$

(
p
,
α
)
=
(
3
,
N
-
4
)

and $$N\ge 3$$

N
≥
3

, then the Morse index of a positive and negative solutions $${{\textsf{m}}}(U^{\pm }_{1,\rho })$$

m
(

U

1
,
ρ

±

)

is completely determined by the ratio $$\rho /R\in (0,1)$$

ρ
/
R
∈
(
0
,
1
)

. Upper and lower bounds for $${{\textsf{m}}}(U^{\pm }_{n,\rho })$$

m
(

U

n
,
ρ

±

)

, $$n\ge 1$$

n
≥
1

, are also obtained when $$(p,\alpha )=(3,N-4)$$

(
p
,
α
)
=
(
3
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Student-led clinics and ePROs to accelerate diagnosis and treatment of patients with axial spondyloarthritis: results from a prospective pilot study
Authors: von Rohr Sophie , Knitza Johannes , Grahammer Manuel , Schmalzing Marc , Kuhn Sebastian , Schett Georg , Ramming Andreas , Labinsky Hannah
Published: July 2023

We aimed to investigate (1) student-led clinics and (2) electronic patient-reported outcomes (ePROs) to accelerate diagnosis and treatment of patients with axial spondyloarthritis (axSpA). Patients with suspected axSpA completed an initial student-led clinic visit (T-1) prior to their planned actual rheumatologist visit (T0). Acceleration of patient appointment and NSAID therapy start, availability of diagnostic findings, and treatment response at T0 were evaluated. Beginning at T-1, patients completed electronic BASDAI questionnaires every 2 weeks. Concordance of paper-based and electronic BASDAI was evaluated. Patient acceptance of ePRO reporting and student-led clinics was measured using the net promoter score (NPS). 17/36 (47.2%) included patients were diagnosed with axSpA. Student-led clinics (T-1) significantly accelerated patient appointments by more than 2 months (T0, T-1, p < 0.0001) and axSpA guideline-conform NSAID treatment (p < 0.0001). At T0, diagnostic workup was completed for all patients and 7/17 (41.2%) axSpA patients presented with a clinically important improvement or were in remission. 34/36 (94.4%) patients completed at least 80% of the ePROs between T-1 and T0. Electronic and paper-administered BASDAI correlated well (r = 0.8 p < 0.0001). Student-led clinics and ePROs were well accepted by patients with NPS scores of + 62.0% (mean ± SD 9.2/10.0 ± 0.9) and + 30.5% (mean ± SD 8.0/10.0 ± 1.7), respectively. In conclusion, student-led clinics and ePRO monitoring were well accepted, accelerated diagnostic workup and treatment in patients with axSpA.
The circadian and photoperiodic clock of the pea aphid
Authors: Colizzi Francesca Sara , Martínez-Torres David , Helfrich-Förster Charlotte
Published: July 2023

The pea aphid, Acyrthosiphon pisum, is a paradigmatic photoperiodic species that exhibits a remarkable annual life cycle, which is tightly coupled to the seasonal changes in day length. During spring and summer, characterised by longer days, aphid populations consist exclusively of viviparous females that reproduce parthenogenetically. When autumn comes and the days shorten, aphids switch their reproductive mode and generate males and oviparous sexual females, which mate and produce cold-resistant eggs that overwinter and survive the unfavourable season. While the photoperiodic responses have been well described, the nature of the timing mechanisms which underlie day length discrimination are still not completely understood. Experiments from the 1960’s suggested that aphids rely on an ‘hourglass’ clock measuring the elapsed time during the dark night by accumulating a biochemical factor, which reaches a critical threshold at a certain night length and triggers the switch in reproduction mode. However, the photoperiodic responses of aphids can also be attributed to a strongly dampened circadian clock. Recent studies have uncovered the molecular components and the location of the circadian clock in the brain of the pea aphid and revealed that it is well connected to the neurohormonal system controlling aphid reproduction. We provide an overview of the putative mechanisms of photoperiodic control in aphids, from the photoreceptors involved in this process to the circadian clock and the neuroendocrine system.
Costs of oropharyngeal squamous cell cancer treatment in Finland
Authors: Tikkanen Juhana , Nieminen Teija , Lassus Patrik , Tenhunen Mikko , Lehtonen Lasse , Mäkitie Antti
Published: July 2023

Background

Oropharyngeal squamous cell carcinoma (OPSCC) can be treated with definitive (chemo)radiotherapy ((C)RT) or primary surgical treatment (PST) with or without postoperative oncologic treatment. The prognosis of OPSCC does not essentially depend on the treatment modality, which allows to consider secondary decision-making aspects such as treatment costs when recommending an individual treatment modality. We attempted to analyze the costs associated with definitive (C)RT and PST in the treatment of OPSCC in Finland.

Materials and methods

We included 73 patients diagnosed with OPSCC at the Helsinki University Hospital (HUS) (Helsinki, Finland) in 2019 and 2020. Treatment costs were defined as the costs incurred in the specialized medical care during the first 12 months after the diagnosis was established.

Results

Definitive RT and definitive CRT were on a 1-year horizon associated with median costs of approximately 10 700€ and 13 300€, respectively; while, the median costs of PST equaled about 40 600€. The costs of definitive (C)RT mostly consisted of the costs of (chemo)radiotherapy sessions; while, the operating room costs and the costs of intensive care and stay on a ward drove the costs of PST.

Conclusions

PST is associated with 2–3 times higher median costs than definitive (C)RT in Finland. The finding differs from the results previously reported in North America, which is related, e.g., to differences in the treatment practices as well as in the regulation of the health care systems.
The prevalence of self-injury in adolescence: a systematic review and meta-analysis
Authors: Farkas Bernadett Frida , Takacs Zsofia K. , Kollárovics Nóra , Balázs Judit
Published: July 2023

In the past 10 years, there has been a growing interest in self-injurious behavior (SIB) among adolescents. The lifetime prevalence of SIB is between 16 and 22% in community sample with females more likely to engage in SIB. There are conflicting results about the global distribution of the prevalence of SIB and whether the SIB has increased in the 21st century. Our aim in the current study was to conduct a systematic search of and meta-analysis on the prevalence of SIB in adolescents over the past 5 years’ worth of published papers and to examine gender, continental, and year differences. We conducted a systematic search in June 2020 of six databases (PubMed, Scopus, Web of Science, OVID Medline, PsycINFO, EBSCO) with three main search terms: “self-injurious behavior,” “prevalence,” and “adolescence.” Article inclusion criteria were (a) written in English; (b) published between January 1, 2015, and June 18, 2020; and (c) focused on a community sample. Titles and abstracts of the articles were screened first. Then, the relevant full texts were read, and those that met the inclusion criteria were collected. We used Comprehensive Meta-Analysis software was used to conduct the analyses. After the screening process 97, articles were included in the meta-analysis. The age of the samples ranged from 11.00 to 18.53 years. The overall average prevalence of nonsuicidal self-injury in the studies was 16%. There was a significant gender difference: females reported a higher prevalence than males (19.4% and 12.9%, respectively). A significantly higher prevalence was found among Asian articles than those from other continents (19.5% and 14.7%, respectively). The prevalence of SIB did not change significantly between 2013 and 2018. The current research draws attention to the high prevalence of SIB among adolescents, especially among females and those living in Asia. It is important to address this behavior, both in terms of prevention and intervention.
A simple electrodeposition problem and the abundant knowledge it subserves to teach
Authors: Péter László
Published: July 2023

This paper presents a handful of electrochemical experiments related to one single system that opens up the way to teach a bunch of topics related to physical and inorganic chemistry, hence serving experience-oriented education of otherwise hard-to-understand fields. The key idea is the electrodeposition of metals from the same bath containing Cu2+ and Ni2+ ions onto electrodes that differ from each other either in size or position within the electrochemical cell. With the proper optimization of the current densities, pure Cu and a Ni-rich coating with shiny silver colour can be obtained on electrodes of large and small surface area, respectively. It will be explained in detail how to drive the discussion on the experiment so that the audience learns which processes can be treated as parallel ones (i.e. the deposition of two metals, Cu and Ni), the mass transport taking place in serial with the electrochemical reaction, and the occurrence of the mass transport limitation in an electrode process. Didactic aspects of the experiment are presented for both high school and undergraduate levels, and control experiments are also suggested to verify the conclusions achieved. Collateral topics of chemistry and materials science that can be brought up in connection with the experiment are also enumerated.
Cost-effectiveness model of trastuzumab deruxtecan as second-line treatment in HER2-positive unresectable and/or metastatic breast cancer in Finland
Authors: Paulissen Jeroen H. J. , Seddik Ahmed H. , Dunton Kyle J. , Livings Christopher J. , van Hulst Marinus , Postma Maarten J. , de Jong Lisa A. , Freriks Roel D.
Published: July 2023

Objectives

Trastuzumab deruxtecan (T-DXd) was recently recommended by the Committee for Medicinal Products for Human Use as a treatment for adult patients with unresectable or metastatic HER2-positive breast cancer, who had received a prior anti-HER2-based regimen. In our study, we evaluated the cost-effectiveness of T-DXd compared with ado-trastuzumab emtansine (T-DM1) for this indication in Finland.

Methods

A three-state partitioned survival analysis model was developed with a payer’s perspective. Time to event data from the DESTINY-Breast03 (DB-03) trial were extrapolated over a lifetime horizon either directly—for progression-free survival and time to treatment discontinuation—or using an alternative approach utilizing long-term T-DM1 survival data and DB-03 data—for overall survival. Discount rates of 3% were applied for costs and effects. Inputs were sourced from the Medicinal Products Database from Kela, Helsinki University Hospital service price list, Finnish Medicines Agency assessments, clinical experts, and DB-03. Sensitivity analyses were performed to characterize and demonstrate parameter uncertainties in the model.

Results

Total quality-adjusted life years (QALYs) and life years (LYs) gained for T-DXd compared with T-DM1 were 1.93 and 2.56, respectively. Incremental costs for T-DXd compared with T-DM1 were €106,800, resulting in an ICER of €55,360 per QALY gained and an ICER of €41,775 per LY gained. One-way sensitivity analysis showed the hazard ratio of T-DXd vs T-DM1 for OS was the most influential parameter. The probabilistic sensitivity analysis showed similar results to the base case.

Conclusions

T-DXd is cost-effective based on surrogate WTP thresholds of €72,000 and €139,000 per QALY.
Troponin dependent 30-day mortality in patients with acute pulmonary embolism
Authors: Sonne-Holm Emilie , Winther-Jensen Matilde , Bang Lia E. , Køber Lars , Fosbøl Emil , Carlsen Jørn , Kjaergaard Jesper
Published: July 2023

Background: Troponin concentrations above upper reference are associated with increased mortality in patients with pulmonary embolism (PE). We aimed to assess whether risk of 30-day mortality increases in a dose-response relationship with concentration of troponin. Methods: Using Danish national registries, we identified patients ≥ 18 years of age hospitalized with first-time PE between 2013 and 2018 and available troponin measurements − 1/+1 day from admission. Patients were stratified into quintiles by increasing troponin concentration. Risk of 30-day mortality was assessed performing cumulative mortality curves and Cox regression model comparing the troponin quintiles. Results: We identified 5,639 PE patients of which 3,278 (58%) had a troponin concentration above upper reference. These patients were older (74 years), 50% male and with heavier comorbidity compared to patients with non-elevated troponin. We found increasing 30-day mortality with increasing troponin concentration (1% in 1st quintile (95% CI 0.5–1.5%), 2% in 2nd quintile (95% CI 1-2.5%), 8% in 3rd quintile (95% CI 5–9%), 11% in 4th quintile (95% CI 9–13%) and 15% in 5th quintile (95% CI 13–16%), confirmed in a Cox model comparing 1st quintile with 2nd quintile (HR 1.09; 95% CI 0.58–2.02), 3rd quintile (HR 3.68; 95% CI 2.20–6.15), 4th quintile (HR 5.51; 95% CI 3.34–9.10) and 5th quintile (HR 8.09; 95% CI 4.95–13.23). Conclusion: 30-day mortality was strongly associated with troponin concentration useful for improving risk stratification, treatment strategies and outcomes in PE patients.