bluuebunny/crossref_metadata_2025 huggingface dataset:
The Impact of Social Media Use on Sleep and Mental Health in Youth: a Scoping Review
Authors: Yu Danny J. , Wing Yun Kwok , Li Tim M. H. , Chan Ngan Yin
Published: February 2024

Purpose of Review

Social media use (SMU) and other internet-based technologies are ubiquitous in today’s interconnected society, with young people being among the commonest users. Previous literature tends to support that SMU is associated with poor sleep and mental health issues in youth, despite some conflicting findings. In this scoping review, we summarized relevant studies published within the past 3 years, highlighted the impacts of SMU on sleep and mental health in youth, while also examined the possible underlying mechanisms involved. Future direction and intervention on rational use of SMU was discussed.

Recent Findings

Both cross-sectional and longitudinal cohort studies demonstrated the negative impacts of SMU on sleep and mental health, with preliminary evidence indicating potential benefits especially during the COVID period at which social restriction was common. However, the limited longitudinal research has hindered the establishment of directionality and causality in the association among SMU, sleep, and mental health.

Recent studies have made advances with a more comprehensive understanding of the impact of SMU on sleep and mental health in youth, which is of public health importance and will contribute to improving sleep and mental health outcomes while promoting rational and beneficial SMU. Future research should include the implementation of cohort studies with representative samples to investigate the directionality and causality of the complex relationships among SMU, sleep, and mental health; the use of validated questionnaires and objective measurements; and the design of randomized controlled interventional trials to reduce overall and problematic SMU that will ultimately enhance sleep and mental health outcomes in youth.
FXR-FGF19 signaling in the gut–liver axis is dysregulated in patients with cirrhosis and correlates with impaired intestinal defence
Authors: Simbrunner Benedikt , Hofer Benedikt S. , Schwabl Philipp , Zinober Kerstin , Petrenko Oleksandr , Fuchs Claudia , Semmler Georg , Marculescu Rodrig , Mandorfer Mattias , Datz Christian , Trauner Michael , Reiberger Thomas
Published: February 2024

Background and aims

Experimental studies linked dysfunctional Farnesoid X receptor (FXR)-fibroblast growth factor 19 (FGF19) signaling to liver disease. This study investigated key intersections of the FXR-FGF19 pathway along the gut–liver axis and their link to disease severity in patients with cirrhosis.

Methods

Patients with cirrhosis undergoing hepatic venous pressure gradient measurement (cohort-I n = 107, including n = 53 with concomitant liver biopsy; n = 5 healthy controls) or colonoscopy with ileum biopsy (cohort-II n = 37; n = 6 controls) were included. Hepatic and intestinal gene expression reflecting FXR activation and intestinal barrier integrity was assessed. Systemic bile acid (BA) and FGF19 levels were measured.

Results

Systemic BA and FGF19 levels correlated significantly (r = 0.461; p < 0.001) and increased with cirrhosis severity. Hepatic SHP expression decreased in patients with cirrhosis (vs. controls; p < 0.001), indicating reduced FXR activation in the liver. Systemic FGF19 (r = −0.512, p < 0.001) and BA (r = −0.487, p < 0.001) levels correlated negatively with hepatic CYP7A1, but not SHP or CYP8B1 expression, suggesting impaired feedback signaling in the liver. In the ileum, expression of FXR, SHP and FGF19 decreased in patients with cirrhosis, and interestingly, intestinal FGF19 expression was not linked to systemic FGF19 levels. Intestinal zonula occludens-1, occludin, and alpha-5-defensin expression in the ileum correlated with SHP and decreased in patients with decompensated cirrhosis as compared to controls.

Conclusions

FXR-FGF19 signaling is dysregulated at essential molecular intersections along the gut–liver axis in patients with cirrhosis. Decreased FXR activation in the ileum mucosa was linked to reduced expression of intestinal barrier proteins. These human data call for further mechanistic research on interventions targeting the FXR-FGF19 pathway in patients with cirrhosis.

Clinical trial number: NCT03267615

Graphical abstract

Physiology of enterohepatic FXR-FGF19 signaling and its regulation in patients with advanced chronic liver disease (ACLD). (FXR) farnesoid X receptor; (FGF19) fibroblast growth factor 19; (BA) bile acids; (c/dACLD) compensated/decompensated advanced chronic liver disease; (FXR) farnesoid X receptor; (SHP) small heterodimer partner; (OST-α/-β) organic solute transporter subunit alpha/beta; (CYP7A1) cholesterol 7 alpha-hydroxylase; (NTCP) Na+-taurocholate cotransporting polypeptide; (CYP8B1) sterol 12-alpha-hydroxylase; (HVPG) hepatic venous pressure gradient; (TJ) tight junctions; (AMP) antimicrobial peptides; (ASBT) Apical Sodium Dependent Bile Acid Transporter; (ZO 1) zonula occludens-1; (OCLN) occluding; (DEFA5) alpha-5-defensin.
A Hessian-Dependent Functional With Free Boundaries and Applications to Mean-Field Games
Authors: Correa Julio C. , Pimentel Edgard A.
Published: February 2024

We study a Hessian-dependent functional driven by a fully nonlinear operator. The associated Euler-Lagrange equation is a fully nonlinear mean-field game with free boundaries. Our findings include the existence of solutions to the mean-field game, together with Hölder continuity of the value function and improved integrability of the density. In addition, we prove the reduced free boundary is a set of finite perimeter. To conclude our analysis, we prove a$$\Gamma $$Γ-convergence result for the functional.
Rare oncogenic alterations in NSCLC—focus on atypical EGFR mutations
Authors: Sharapova Yana , Loges Sonja , Janning Melanie
Published: February 2024

In non-small cell lung cancer (NSCLC), mutations within the epidermal growth factor receptor (EGFR) gene are very common driver mutations. EGFR tyrosine kinase inhibitors (TKIs), have shown remarkable efficacy in patients with common classical EGFR mutations (L858R and exon 19 deletions). However, the landscape becomes intricate with atypical (also known as uncommon) EGFR mutations, comprising up to 30% of cases. This brief review provides an insight into recent studies, shedding light on the challenges and opportunities posed by uncommon mutations. The exploration encompasses clinical outcomes, treatment responses, and innovative approaches such as structure-based classifications, offering insights into the evolving paradigm of precision medicine for NSCLC patients with diverse EGFR mutations.
Numerical Treatment of a Two-Parameter Singularly Perturbed Elliptic Problem with Discontinuous Convection and Source Terms
Authors: Shiromani Ram , Shanthi Vembu , Ramos Higinio
Published: February 2024

In this paper, we address a two-parameter singularly perturbed convection-reaction-diffusion 2-D problem. We also consider that the convection and source terms are discontinuous in space. Due to these discontinuities and the presence of perturbation parameters, solutions to such problems show boundary and interior layers. In this study, we have carried out a numerical approach using a finite-difference technique with an appropriate layer-adapted piecewise uniform Shishkin mesh. Some examples are presented which show the best performance of the proposed method and its agreement with the theoretical analysis.
Response of runoff to climate change in the Manas River Basin flow-producing area, Northwest China
Authors: Gu Xinchen , Long Aihua , He Xinlin , Wang Hao , Lai Xiaoying , Pang Ning , Liu Huan , Yu Haoran
Published: February 2024

The inland river basins of northwestern China are structured as mountain-basin systems. Water resources originate in the flow-producing area (FPA), are utilized and operated in the oasis area and are dissipated in the desert area. In this study, a Soil and Water Assessment Tool (SWAT) model was constructed in the Manas River Basin (MRB) FPA. Meanwhile, it simulated climate change and runoff evolution trends in the FPA of the MRB under different four climate change scenarios of Coupled Model Intercomparison Project Phase 5. The main findings showed that (1) the years 1979–1980 were chosen as the model warm-up period, 1979–2000 as the model calibration period and 2001–2015 as the model validation period to complete the construction of the SWAT model for MRBFPA. From 1981 to 2015, three performance parameters indicated that the model accuracy meets the requirements (NSE = 0.81, R2 = 0.81 and PBIAS = 1.44) and can be used for further studies; (2) the hydrological elements (e.g. runoff, potential evapotranspiration, evapotranspiration, soil water content, snowmelt) in the MRBFPA were analysed by the constructed SWAT model; (3) the climate change in the MRBFPA is close to the RCP 8.5 scenario, and the future changes in water resources under this scenario will range from 659 to 2308 (million)m3. Compared to the multi-year historical mean value (12.95 × 108 m3), the future fluctuation in the amount of water resources available in this basin is increasing.
S4D-ECG: A Shallow State-of-the-Art Model for Cardiac Abnormality Classification
Authors: Huang Zhaojing , Herbozo Contreras Luis Fernando , Yu Leping , Truong Nhan Duy , Nikpour Armin , Kavehei Omid
Published: February 2024

Purpose

This study introduces an algorithm specifically designed for processing unprocessed 12-lead electrocardiogram (ECG) data, with the primary aim of detecting cardiac abnormalities.

Methods

The proposed model integrates Diagonal State Space Sequence (S4D) model into its architecture, leveraging its effectiveness in capturing dynamics within time-series data. The S4D model is designed with stacked S4D layers for processing raw input data and a simplified decoder using a dense layer for predicting abnormality types. Experimental optimization determines the optimal number of S4D layers, striking a balance between computational efficiency and predictive performance. This comprehensive approach ensures the model's suitability for real-time processing on hardware devices with limited capabilities, offering a streamlined yet effective solution for heart monitoring.

Results

Among the notable features of this algorithm is its strong resilience to noise, enabling the algorithm to achieve an average F1-score of 81.2% and an AUROC of 95.5% in generalization. The model underwent testing specifically on the lead II ECG signal, exhibiting consistent performance with an F1-score of 79.5% and an AUROC of 95.7%.

Conclusion

It is characterized by the elimination of pre-processing features and the availability of a low-complexity architecture that makes it suitable for implementation on numerous computing devices because it is easily implementable. Consequently, this algorithm exhibits considerable potential for practical applications in analyzing real-world ECG data. This model can be placed on the cloud for diagnosis. The model was also tested on lead II of the ECG alone and has demonstrated promising results, supporting its potential for on-device application.
Quality of stapled mesenteric defect closure influences the chance of reopening after laparoscopic Roux-en-Y gastric bypass surgery
Authors: Bruinsma F. F. E. , van der Burg S. J. C. , El Adel S. , Schouten R. , Smeets S. J. M.
Published: February 2024

Internal herniation (IH) is a common problem after laparoscopic Roux-en-Y gastric bypass surgery (RYGB). Routine closure of the mesenteric defects (MDs) reduces the risk of IH. Only very few articles report on risk factors for IH or describe detailed closing techniques. There is no consensus yet on the best closing method. The objective of this study is to determine the optimal stapling method for closure of MDs after RYGB. All performed RYGB procedures in our high-volume bariatric institute were included. Quality of the closure was scored in the categories poor, sub-optimal, and optimal, to see if the quality of the closure would predict the chance of reopening of the MDs and, therefore, the chance of IH. During any type of laparoscopy in the follow-up of the patient, the conditions of the MDs were stated, for example during diagnostic laparoscopy in symptomatic patients suspicious for IH or during laparoscopic cholecystectomy. Technically well-executed closure of Petersen’s space (PS) with two rows of staples had a greater chance of still being closed upon re-inspection compared to closure with one row (odds ratio = 8.1; 95% confidence interval [1.2–53.2], p = 0.029). Optimal closure of the MD at the jejuno-jejunostomy (JJ-space, JJS) resulted in more closed JJSs upon re-inspection compared to sub-optimal closure (odds ratio = 3.6 [CI 95% 0.8–16.1], p = 0.099). Non-optimally closed MDs had higher reopening rates and, therefore, pose an additional risk for IH. Our classification provides a quality assessment of MD closure during RYGB and gives insight into how to optimize surgical technique.
Effect of PV Plant on Frequency Stability in IEEE12 Bus System for Different Penetration Levels and Depth of Frequency Support
Authors: Çavdar Bora , Akyazi Ömür , Şahin Erdinç , Nuroğlu Mehmet
Published: February 2024

The utilization of renewable energy sources, particularly large-scale photovoltaic plants (PVPs), has been increasing in power systems. However, the high penetration of PVPs in power systems has implications for the system's moment of inertia and frequency response. Therefore, it is crucial to thoroughly investigate the impact of PVPs on system frequency. This study focuses on investigating the effects of a large-scale PVP at various penetration levels on frequency and the depth of frequency support. The study proposes a strategy aimed at maximizing power generation from PVPs while also providing support to system frequency. To assess the effects of PVPs, the study examines events such as load outages, generator outages, load changes, and three-phase short circuits. Additionally, the relationship between voltage and frequency during these events is considered, with the load represented by an impedance model. By studying the depth of frequency support alongside different penetration levels, the study provides a detailed understanding of the impact of PVPs on frequency. The study aims to determine the threshold at which the penetration level of PVPs becomes significant in terms of frequency support. This analysis sheds light on the point at which the presence of PVPs begins to exert a notable influence on frequency stability and support within the power system. Overall, the study contributes to the integration of PVPs in power systems by providing insights into their impact on frequency dynamics and proposing strategies to enhance power generation and frequency support simultaneously.
Flow and hardening behavior in the heat-affected zone of welded ultra-high strength steels
Authors: Afkhami Shahriar , Amraei Mohsen , Javaheri Vahid , Ghafouri Mehran , Björk Timo , Salminen Antti , Zhao Xiao-Lin
Published: February 2024

The applications of thermomechanically processed ultra-high strength steels (UHSS) are rapidly increasing, and welding these UHSSs seems inevitable in steel structures. However, welding heat causes unwanted microstructural transformations in the heat-affected zone (HAZ). Due to the localized nature of these changes throughout the HAZ, evaluating the true stress–strain values of these localized HAZ subzones is essential to improve the accuracy of analytical or numerical models. Hence, this study utilized experimental thermal simulations to replicate HAZ subzones of two types of UHSSs, i.e., direct-quenched S960 and quenched-and-tempered S1100, and employed tensile test in conjunction with digital image correlation to plot the true stress–strain and hardening curves of the subzones. Both UHSSs manifested similar trends but with various fluctuations in their hardening capacities throughout their HAZ subzones. Next, hardening parameters from Hollomon, Voce, and Kocks-Mecking approaches were extracted by fitting the experimental results with the semi-empirical equations. For both UHSS types, the Voce approach, on average, was more accurate in modeling the plastic deformation. Also, hardening parameters achieved via the Voce approach’s fittings agreed with the parameters from Kocks-Mecking plots; this consistency pointed to the predictability of the plastic flow and hardening behavior of both UHSS types. According to the microstructural investigations, the hardening behavior of the investigated HAZ subzones depended on two types of microstructure constituents: ferritic and lath-like features. Ferritic features dominantly governed the plastic flow and hardening near the fusion line, while by getting distant from the fusion line, the lath-like features became more dominant.
Rationing in an Era of Multiple Tight Constraints: Is Cost-Utility Analysis Still Fit for Purpose?
Authors: Dakin Helen , Tsiachristas Apostolos
Published: February 2024

Cost-utility analysis may not be sufficient to support reimbursement decisions when the assessed health intervention requires a large proportion of the healthcare budget or when the monetary healthcare budget is not the only resource constraint. Such cases include joint replacement, coronavirus disease 2019 (COVID-19) interventions and settings where all resources are constrained (e.g. post-COVID-19 or in low/middle-income countries). Using literature on health technology assessment, rationing and reimbursement in healthcare, we identified seven alternative frameworks for simultaneous decisions about (dis)investment and proposed modifications to deal with multiple resource constraints. These frameworks comprised constrained optimisation; cost-effectiveness league table; ‘step-in-the-right-direction’ approach; heuristics based on effective gradients; weighted cost-effectiveness ratios; multicriteria decision analysis (MCDA); and programme budgeting and marginal analysis (PBMA). We used numerical examples to demonstrate how five of these alternative frameworks would operate. The modified frameworks we propose could be used in local commissioning and/or health technology assessment to supplement standard cost-utility analysis for interventions that have large budget impact and/or are subject to additional constraints.
Recent advances in ocular lubrication
Authors: Zhang Jianhua , Su Yunjuan , Wu Jian , Wang Hongdong
Published: February 2024

The ocular lubrication, where the eyelid constantly slides on the curved corneal surface, is considered as one of primary lubrication systems in bio-tribology. Under reliable lubrication conditions, sensitive ocular tissues remain intact from fatigue damage during spontaneous blink cycles. The tear film, evenly filled between cornea and conjunctiva, is a biological fluid with dynamic adjustment ability, which provides superior lubrication with the friction coefficient of below 0.01. However, the lubrication failure may result in a variety of uncomfortable symptoms such as inflammatory reactions, tissue damage and neurological abnormalities. Therefore, it is essential to clarify the fundamental mechanism of ocular lubrication, which helps to alleviate and even recover from various ocular symptoms. This review firstly demonstrates that the ocular components, containing lipids and mucins, contribute to maintaining the lubrication stability of tear film. Furthermore, the ocular lubrication state in various physiological environments and the physical effect on tear film dynamics are further discussed. As typical applications, the therapeutic agents of dry eye syndrome and contact lens with superior lubrication effects are introduced and their lubrication mechanisms are clarified. Finally, this review summarizes a series of the latest research inspired by ocular lubrication. Overall, this work will provide a valuable guidance on the theoretical research and extensive applications in the field of biological lubrication.
Nano friction behaviour between magnetic materials and copper considering the inter-diffusion effect
Authors: Li Zilin , Dou Lisha , Yang Shiyu , Ouyang Huajiang , Zhu Qichen , Chen Xiaoyang , Jia Xin , Dou Shuaiwei , Cui Xiaolong , Zhang Yudong , Qiu Jingjiang , Qi Guochen , Nie Bangbang , Liu Pan , Wei Ronghan
Published: February 2024

Copper, permalloy, cobalt, and silicon are the materials that have been widely utilised in magnetic devices. When the size of interest is down to the nanoscale, the inter-diffusion between certain materials becomes influential. This paper studies the nanoscale friction characteristics between frictional pairs with and without inter-diffusion properties through the atomic force microscope. The distinct evolution features of nanoscale friction force when inter-diffusion is involved are discovered experimentally, which is also confirmed through theoretical analysis. Firstly, through the thin film deposition method, four pairs of contact materials (Cu–Ni81Fe19, Si–Ni81Fe19, Cu–Co, Cu–Si) are designed for friction tests, in which diffusion occurs at the interface of Cu–Ni81Fe19 pair. Then, the effects of sliding velocity and loading force on the nano friction of each pair are measured. It is found that regardless of the diffusion phenomenon: (1) the adhesion force values exhibit a notable correlation to the values of the friction force; (2) the friction force in all four material pairs consistently increases with the growth of the normal loading force, although the growth rate may differ. In terms of the sliding velocity effect, the friction forces of immiscible materials (Si–Ni81Fe19, Cu–Co, and Cu–Si) are found to increase with the increasing sliding velocity. However, the friction force of Cu–Ni81Fe19, decreases with the increasing sliding velocity. Furthermore, a compositive friction model considering both the velocity and the normal force effect was proposed, which shows good agreement with the experimental results and explains the nano friction behaviour of both miscible and immiscible metals.
Modeling and analysis for material removal and surface roughness in fluid jet polishing of optical glass
Authors: Cao Zhongchen , Wang Ming , Liu Haitao , Huang Tian
Published: February 2024

Fluid jet polishing (FJP) is a non-contact polishing technology that can fabricate free-form optical surfaces with sub-micron-level form accuracy and nano-level surface roughness, especially for hard and brittle materials. The surface generation model of FJP can be used to guide the determination and optimization of process parameters and is of great significance for understanding the evolution mechanism of surface microtopography. However, predictive models for the microscopic topography of polished surfaces are still lacking. This study established a macroscopic surface profile model for predicting 3D material removal characteristics and surface texture by combining the 3D computer fluid dynamics (CFD) simulation model and single-particle erosion mechanism. A fractal theory-based erosion model has been built to calculate the material removal caused by the erosion of a single abrasive particle on the rough surface; thus, it predicts the micro-topography and surface roughness of the polished samples. A series of polishing experiments were conducted to analyze the feasibility and accuracy of the model quantitatively and study the influence mechanism of process parameters on the material removal characteristics and surface quality. Results indicated that the models could well predict material removal and surface roughness. The prediction accuracy of the surface roughness Ra and maximum removal depth is better than 91.6% and 90%, respectively. It is also found that the material removal rate of FJP could reach 0.517 mm3/min, and the surface roughness convergence rate could reach 62.9%.
Role of IL33 in chronic inflammation and microvascular damage as a reflection of organ damage on a cohort of patients with acromegaly
Authors: Costa D. , Pellicano C. , Mercuri V. , D’Ascanio E. , Buglione G. , Cicolani G. , Basile U. , Leodori G. , Gargiulo P. , Rosato E.
Published: February 2024

Aim

Acromegaly is a rare chronic disease, caused by the over-secretion of growth hormone (GH), that creates a pro-inflammatory state, but the exact mechanisms by which GH or insulin-like growth factor 1 (IGF-1) act on inflammatory cells are not fully understood. Aim of the study was to evaluate Interleukin-33 (IL33) and the skin perfusion of hands in patients with acromegaly (AP) and healthy controls (HC).

Methods

IL33 have been assessed in 40 AP and 40 HC. IL 33 was determined and skin perfusion of hands was assessed by laser speckle contrast analysis (LASCA) in both populations.

Results

IL33 was significantly higher in AP compared to HC [45.72 pg/ml (IQR 28.74–60.86) vs 14 pg/ml (IQR 6.5535); p < 0.05]. At LASCA, peripheral blood perfusion (PBP) was significantly lower in AP compared to HC [53.39 pU (IQR 40.94–65.44) vs 87 pU (IQR 80–98) p < 0.001]. The median values of ROI1, ROI2 and ROI3 were significantly lower in AP compared to HC [97.32 pU (IQR 50.89–121.69) vs 131 pU (IQR 108–135); p < 0.001], [58.68 pU (IQR 37.72–84.92) vs 83 pU (IQR 70–89), p < 0.05] and HC [52.16 (34.47–73.78) vs 85 (78–98), p < 0.001], respectively. The proximal–distal gradient (PDG) was observed in 18 of 40 (45%) AP.

Conclusion

Serum IL33 is higher in AP compared to HC; conversely a reduction of PBP of hands was present in AP compared to HC, probably due to endothelial dysfunction, strictly dependent on acromegaly and are not influenced by the choice of treatment.
Retinal spike train decoder using vector quantization for visual scene reconstruction
Authors: Ma Kunwu , Raj Alex Noel Joseph , Rajangam Vijayarajan , Tjahjadi Tardi , Liu Minying , Zhuang Zhemin
Published: February 2024

The retinal impulse signal is the basic carrier of visual information. It records the distribution of light on the retina. However, its direct conversion to a scene image is difficult due to the nonlinear characteristics of its distribution. Therefore, the use of artificial neural network to reconstruct the scene from retinal spikes has become an important research area. This paper proposes the architecture of a neural network based on vector quantization, where the feature vectors of spike trains are extracted, compressed, and stored using a feature extraction and compression network. During the decoding process, the nearest neighbour search method is used to find the nearest feature vector corresponding to each feature vector in the feature map. Finally, a reconstruction network is used to decode a new feature map composed of matching feature vectors to obtain a visual scene. This paper also verifies the impact of vector quantization on the characteristics of pulse signals by comparing experiments and visualizing the characteristics before and after vector quantization. The network delivers promising performance when evaluated on different datasets, demonstrating that this research is of great significance for improving relevant applications in the fields of retinal image processing and artificial intelligence.
Test Setup for Investigating the Impact Behavior of Biaxially Prestressed Composite Laminates
Authors: Pongratz C. , Tix J. , Wolfrum J. , Gerke S. , Ehrlich I. , Brünig M.
Published: February 2024

Instrumented impact testing and compression-after-impact testing are important to adequately qualify material behavior and safely design composite structures. However, the stresses to which fiber-reinforced plastic components are typically subjected in practice are not considered in the impact test methods recommended in guidelines or standards. In this paper, a test setup for investigating the impact behavior of composite specimens under plane uniaxial and biaxial preloading is presented. For this purpose, a special test setup consisting of a biaxial testing machine and a specially designed drop-weight tower was developed. The design decisions were derived from existing guidelines and standards with the aim of inducing barely visible impact damage in laminated carbon fiber-reinforced plastic specimens. Several measurement systems have been integrated into the setup to allow comprehensive observation of the impact event and specimen behavior. A feasibility test was performed with biaxially prestressed carbon fiber-reinforced plastic specimens in comparison with unstressed reference tests. The compressive-tensile prestressing resulted in lower maximum contact forces, higher maximum deflections, higher residual deflections and a different damage pattern, which was investigated by light microscopic analysis. Finally, the functionality of the experimental setup is discussed, and the results seem to indicate that the test setup and parameters were properly chosen to investigate the effect of prestresses on the impacts behavior of composite structures, in particular for barely visible subsequent damages.
Effect of natural fractures on mechanical properties and fracture patterns of shale at microscopic scale: an example from the Lower Cambrian Niutitang formation in Qianbei region
Authors: Wu Zhong-Hu , Yang Chao , Zuo Yu-Jun , Lou Yi-Li , Song Huai-Lei , Cui Heng-Tao , Tang Mo-Tian
Published: February 2024

In order to explore the influence of natural fractures on the mechanical properties and failure modes of shale at the micro scale, uniaxial compression numerical experiments were conducted on the shale of the Niutang Formation in northern Guizhou with different natural fracture angles using a rock failure process system and digital image processing technology. It is shown that the compressive strength of shale increases with the increase of natural crack inclination, and the growth rate of shale compressive strength also increases. Shale's microscopic fractures can generally be classified into four categories. The first category is to sprout along the natural cracks to the outside of the shale, and eventually form a crack similar to the "X" type (0°); the second category is to sprout along the natural cracks to the middle and outside of the shale, and eventually form an inverted "Y" type crack (15°, 30°); the third category is to sprout along the natural cracks to the middle and outside of the shale, and eventually form an inverted "Y" type crack (15°, 30°); the second type sprouts along the natural fractures toward the middle and outside of the shale, forming inverted "Y"-type fractures (15°, 30°); the third type cracks along the sides of the natural fractures, forming "Y"-type fractures (45°); and the fourth type does not crack along the natural fractures, forming "S"-type fractures (60°, 75°, and 90°). In the low natural fracture dip shale model, tensile damage mainly occurs, accompanied by a small amount of compressive shear damage; in the high natural fracture dip shale model, tensile damage and compressive shear damage account for a larger proportion in the fracture process.This suggests that the presence of natural cracks in shale has a significant impact on stress distribution. There are two main types of acoustic emission signal distribution and evolutionary features, the evolutionary features of acoustic emission signal distribution are of two types, 0°-45° test and 60°-90° test, and the difference is mainly reflected in the damage stage, the damage of shale with high natural fracture inclination is more intense, which is manifested by the decrease in the number of acoustic emission events, but the level of acoustic emission events in the damage stage is higher, which can reach 61788, 46605 and 94315, the shale with high natural fracture inclination is more brittle.
Damage and hardening evolution characteristics of sandstone under multilevel creep–fatigue loading
Authors: Bichuan Zhang , Yunpei Liang , Quanle Zou , Yanhao Ning , Fanjie Kong
Published: February 2024

During the operation of artificial underground structures, the surrounding rock experiences fatigue and creep damage caused by several types of disturbances under long-term constant loading. To quantify the mechanical response of sandstone under creep–fatigue loading, a damage–hardening evolution model based on the linear superposition concept is proposed. In the model, coupling is applied to represent the synergistic effect of creep and fatigue. Creep–fatigue tests of sandstone specimens are conducted under multilevel loading. The damage and hardening effects of sandstone under creep–fatigue loading are complex. Hardening is the dominant effect under low creep–fatigue loads, and damage is the dominant effect under high creep–fatigue loads. The strength of the rock specimens undergoes increasing and decreasing trends under this loading path, and the evolution of the Mohr–Coulomb envelope is discussed. The proposed model can be used to describe the test data and the evolution of the creep–fatigue process. With increasing creep–fatigue number, the acoustic emission amplitude, energy, and cumulative counts increase. However, the amplitude is more sensitive than the energy, indicating that it is more suitable for describing creep–fatigue loading. Furthermore, the peak frequencies of the AE signals are mostly distributed in the 0–15 kHz, 15–30 kHz, 30–45 kHz, and 45–55 kHz regions. The signal proportion in the 45–55 kHz zone decreases with the creep–fatigue number. However, other frequency zones increase with the creep–fatigue number. This phenomenon illustrates that the crack scale of the specimens increases with the creep–fatigue number.
Student perspectives on the use of generative artificial intelligence technologies in higher education
Authors: Johnston Heather , Wells Rebecca F. , Shanks Elizabeth M. , Boey Timothy , Parsons Bryony N.
Published: February 2024

The aim of this project was to understand student perspectives on generative artificial intelligence (GAI) technologies such as Chat generative Pre-Trained Transformer (ChatGPT), in order to inform changes to the University of Liverpool Academic Integrity code of practice. The survey for this study was created by a library student team and vetted through focus groups. A total of 2555 students participated in the survey. Results showed that only 7% of students who responded had not heard of any GAI technologies, whilst over half had used or considered using these for academic purposes. The majority of students (54.1%) were supportive or somewhat supportive of using tools such as Grammarly, but 70.4% were unsupportive or somewhat unsupportive towards students using tools such as ChatGPT to write their whole essay. Students who had higher levels of confidence in their academic writing were less likely to use or consider using them for academic purposes, and were also less likely to be supportive of other students using them. Most students (41.1%) also thought there should be a university wide policy on when these technologies are or are not appropriate to use. The results of this research suggest that students require clear policies on the use of GAI and that these technologies should not be banned from university, but consideration must be made to ensure different groups of students have equal access to the technologies.
Feedback-Memory: An approach to promoting the social acceptance of students rarely receiving positive teacher feedback
Authors: Spilles Markus , Huber Christian , Nicolay Philipp
Published: February 2024

In line with social referencing theory, recent studies have revealed that teacher feedback might be an important factor influencing how students are socially accepted by their peers. This study investigates the effects of an intervention aiming to enhance the social acceptance of students rarely receiving positive teacher feedback – the Feedback-Memory approach. Feedback-Memory was designed as a multi-component intervention with 4 elements: 1) Identifying students rarely receiving positive teacher feedback (target students), 2) giving positive teacher feedback to students (especially to the target students) at the end of every lesson, 3) asking classmates to remember positive teacher feedback at the end of the school day, and 4) rewarding students for remembering the teacher feedback content. Two main research questions are investigated within our study: 1) Does playing Feedback-Memory increase the frequency of classmates-perceived positive teacher feedback towards students rarely receiving positive teacher feedback? 2) Does playing Feedback-Memory increase the social acceptance of students rarely receiving positive teacher feedback? Twenty-five classes (fourth grade) and 531 students participated in this study in German elementary schools. Classes were randomly assigned to 10 intervention classes and 15 control classes. In every intervention and control class, the 5 students least likely to be receiving positive teacher feedback were identified. Results of multilevel analysis reveal that the Feedback-Memory intervention significantly enhanced the classmates-perceived positive teacher feedback and the social acceptance of the target students compared to students in the control group and their classmates.
Endophytic community in juvenile Acer pseudoplatanus and pathogenicity of Cryptostroma corticale and other associated fungi under controlled conditions
Authors: Bußkamp Johanna , Bien Steffen , Neumann Leonard , Blumenstein Kathrin , Terhonen Eeva , Langer Gitta Jutta
Published: February 2024

The causative agent of sooty bark disease, Cryptostroma corticale, has, for some years, caused increased damage to maples (Acer spp.) in Germany and throughout Europe. It has been stated that this pathogen can occur latently in Acer. In this study, the composition of endophytic fungi of woody stem tissues of sycamore (Acer pseudoplatanus) saplings were analysed in order to investigate whether C. corticale is present in young, visually healthy maple trees from natural regeneration. The most abundant taxa of the 30 isolated endophytes were Diaporthe cf. rudis and Petrakia irregularis. An association of five fungal species (Biscogniauxia mediterranea, Coniochaeta velutina, Gibellulopsis catenata, Neocucurbitaria quercina, Tangerinosporium thalitricola) with A. pseudoplatanus was reported for the first time. Cryptostroma corticale was not present in the juvenile sycamore stems. Furthermore, its pathogenicity was studied in comparison to other pathogens associated with A. pseudoplatanus, namely Diplodia mutila, Dothiorella sp., Nectria cinnabarina, Neonectria coccinea, Neonectria punicea and Stegonsporium pyriforme. The longest necroses were induced by C. corticale followed by N. coccinea. In a trial with a C. corticale spore suspension sprayed directly on stem bark, the fungus could be re-isolated from woody tissue, however necroses were evoked only when the bark was wounded prior to infection. The results from the experiments presented here function as additional evidence for the ability of C. corticale to establish endophytically within the host and, in particular, for the ability of the fungus to establish a successful infection/entrance through intact bark.
Interactions between a circular city and other sustainable urban typologies: a review
Authors: Pegorin Maria Cristina , Caldeira-Pires Armando , Faria Emilia
Published: February 2024

Urban systems play a central role in the transition to the circular economy, and cities' role in consumption makes them essential for sustainable development. The transition to a circular city can help urban centers become consumers of waste and generators of the resources necessary for their maintenance through optimized and prolonged life cycles. In this sense, this article aims to identify the characteristics of a circular city and compare them to other sustainable urban typologies: sustainable city, green city, smart city, resilient city, eco-city, low-carbon city, and city with nature-based solutions. It follows a qualitative approach with a narrative review of the literature in articles from the Scopus database and reports from international organizations. This article demonstrates that a circular city adopts the 10R framework principles of a circular economy by implementing strategies to regenerate, share, optimize, cycle, and replace resources. It also highlights that the study of the methodologies and strategies for transition to a circular city interconnect with all sustainable urban typologies. Thus, the transition to a circular city contributes to urban sustainability in all dimensions.
Energy management strategy for a hybrid micro-grid system using renewable energy
Authors: Ndeke Christian Bipongo , Adonis Marco , Almaktoof Ali
Published: February 2024

This paper introduces an energy management strategy for a hybrid renewable micro-grid system. The efficient operation of a hybrid renewable micro-grid system requires an advanced energy management strategy able to coordinate the complex interactions between different energy sources and loads. This strategy must consider some factors such as weather fluctuations and demand variations. Its significance lies in achieving the overarching objectives of these systems, including optimizing renewable energy utilization, reducing greenhouse gas emissions, promoting energy independence, and ensuring grid resilience. The intermittent nature of renewable sources necessitates a predictive approach that anticipates the energy availability and adjusts the system operation. The aim of this study was to develop an energy management system for a hybrid renewable micro-grid system to optimize the deployment of renewable energy resources and increase their integration in the power system. Therefore, the main objective of this work was to develop an energy management strategy that controls the flow of energy between the hybrid micro-grid system and the load connected directly as well as the load connected to the utility grid using MATLAB/Simulink software. The second objective was to control the charging and discharging of the battery. The results show that the developed algorithm was able to control the energy flow between the hybrid micro-grid system and the utility grid and also to ensure a proper relation between the charging /discharging rate of the battery based on their operating conditions. In this application, the battery was charged at higher power. It was seen that a higher charging power enables to fully recharge the battery in a shorter amount of time than usual. The results have shown that it is possible to maximize the charging time by using a greater power and this algorithm ensures the state of charge (SOC) of battery to remain in the admissible limits (between 20 and 100%).
Test of the gravitational redshift with single-photon-based atomic clock interferometers
Authors: Liu Ju , Xu Yaoyao , Luo Huaqing , Cao Lushuai , Zhou Minkang , Duan Xiaochun , Hu Zhongkun
Published: February 2024

The gravitational redshift (GR), as predicted by Einstein’s general theory of relativity, posits that two identical clocks situated at different gravitational potentials will tick at different rates. In this study, we explore the impact of the GR on a single-photon-based atom interferometer and propose a corresponding testing scheme. Our approach conceptualizes the atom interferometer as two coherent atomic clocks positioned at distinct elevations, which is referred to as an atomic clock interferometer, allowing us to derive the GR-induced phase shift. This effect becomes significant due to the notable energy difference between the two atomic internal states, comparable to other relativistic effects in single-photon-based atomic clock interferometers. Furthermore, our proposed scheme incorporates the velocity of the laser device to effectively mitigate other relativistic effects. The ensuing analysis indicates an anticipated GR test precision at the 10−5 level for our proposed approach.
Quantum Poisson solver without arithmetic
Authors: Wang Shengbin , Wang Zhimin , Cui Guolong , Shi Shangshang , Shang Ruimin , Li Jiaxin , Li Wendong , Wei Zhiqiang , Gu Yongjian
Published: February 2024

Solving differential equations is one of the most promising applications of quantum computing. The Poisson equation has applications in various domains of physics and engineering, including the simulation of ocean current dynamics. Here, we propose an efficient quantum algorithm for solving the one-dimensional Poisson equation based on the controlled Ry rotations. Our quantum Poisson solver (QPS) removes the need for expensive routines such as phase estimation, quantum arithmetic or Hamiltonian simulation. The computational cost of our QPS is 3n in qubits and 5/3n3 in one- and two-qubit gates, where n is the logarithmic of the number of discrete points. An overwhelming reduction of the constant factors of the big-O complexity is achieved, which is critical to evaluate the practicality of implementing the algorithm on a quantum computer. In terms of the error ε, the complexity is log(1/ε) in qubits and poly(log(1/ε)) in operations. The algorithms are demonstrated using a quantum virtual computing system, and the circuits are executed successfully on the IBM real quantum computers. The present QPS could exhibit a potential real-world application for solving differential equations on noisy intermediate-scale quantum (NISQ) devices.
Using Data from Uniform Rate Applications for Site-Specific Nitrogen Recommendations
Authors: Park Eunchun , Brorsen B. Wade , Li Xiaofei
Published: February 2024

Much historical yield-monitor data is from fields where a uniform rate of nitrogen was applied. A new approach is proposed using this data to get site-specific nitrogen recommendations. Bayesian methods are used to estimate a linear plateau model where only the plateau is spatially varying. The model is then illustrated by using it to make site-specific nitrogen recommendations for corn production in Mississippi. The in-sample recommendations generated by this approach return an estimated $9/acre on the example field. The long-term goal is to combine this information with other information such as remote sensing measurements.
Knowledge Flows and Industrial Clusters: Assessing the Sources of Competitive Advantage in Two English Regions
Authors: Corker Chris , Lane Joe , Wilson John F.
Published: February 2024

How knowledge is created, accessed, stored and disseminated has become a major focus of study when assessing the success or failure of industrial clusters. Marshall (1890; 225) initiated this debate when he noted: ‘The mysteries of the trade become no mysteries; but are as it were in the air’. In the edited collection by Wilson, Corker and Lane (2022), emphasis has been placed on the links between knowledge, knowledge flows and how innovation systems evolve and adapt. This paper builds on their work examining how tacit and codified knowledge is created and disseminated across a cluster. Bathelt et al (2004) have demonstrated how successful clusters build effective ‘global pipelines’ to access knowledge generated elsewhere, prompting us to think how a business history analysis can incorporate these concepts and how these processes have worked in practice. The paper analyses two English clusters and the processes involved in the formation of a common body of knowledge, a ‘knowledge-cum-industrial zeitgeist’ which explains the cluster’s performance. Specifically, it proposes a model that links internally-generated knowledge and ‘global pipelines’ that clusters develop to tap into externally-generated knowledge, which through effective feedback into the ‘local buzz’ results in further innovation and strengthens the cluster’s competitive advantage.