bluuebunny/crossref_metadata_2025 huggingface dataset:
Low-order isotropic spatial resolution characteristics of the viscous terms for LES analysis on iso/anisotropic steady turbulent flows
Authors: Hirabayashi Riku , Suzuki Hiroki , Mochizuki Shinsuke
Published: September 2023

This study aims to clarify the effect of reducing the isotropic spatial resolution on the turbulence field obtained in the Large Eddy Simulation (LES). Here, isotropic or anisotropic steady turbulence is analysed in this LES. A linear forcing method is used to generate these steady turbulent flows. Although the spatial resolution can be enhanced by increasing the number of spatial grid points or by using higher-order discrete forms, the isotropic resolution is only sometimes maintained. This viewpoint is expected to be particularly evident in the present study, especially in the LES analysis of wall turbulence. The present study focuses mainly on the spatial resolution of the viscous terms, where the spatial resolution can be varied while maintaining isotropy. Here, the discretisation accuracy order of the viscous terms was set from second to eighth order. In this study, the discretisation accuracy order of the convection terms is also varied. As shown in this study, the effect of the viscous term on the turbulence fields is larger than that of the discretisation accuracy order of the convection terms. There is a difference in the characteristics of the turbulence field obtained when the discretisation accuracy of the viscosity terms is of second and fourth or higher order.
Research on operation characteristics and control strategy of hybrid multi-feed HVDC system
Authors: Wang Ting , Hu Xinyang , Zhang Longen , Ye Pangqi
Published: September 2023

Flexible DC transmission technology based on voltage source converter (VSC-HVDC) and high voltage DC transmission technology based on grid commutation converter (LCC-HVDC) have complementary characteristics, so the hybrid DC technology combined with LCC-HVDC and VSC-HVDC can make them complement each other and become the development trend of power grid technology in the future. In the existing hybrid multi-infeed DC system, conventional DC transmission (LCC-HVDC) and flexible DC transmission (VSC-HVDC) operate independently and are not coordinated with each other, but there is a blank in the research on the protection coordination relationship between VSC/LCC parallel DC hybrid system and its near area AC system. Therefore, it is necessary to theoretically analyse and study the operation characteristics, control strategy and protection coordination relationship between near-area AC systems of hybrid multi-infeed HVDC systems. Due to the limited space, this paper mainly analyses the operation characteristics and control strategy of hybrid multi-infeed HVDC system, and verifies the correctness of the theory through simulation research. In the next step, the corresponding protection is configured in the above simulation model, and the protection adaptability analysis and protection optimization scheme of hybrid multi-infeed HVDC system are obtained.
Daily load prediction study on SCASL and BiGRU models
Authors: Li Qiaosen , Chen Li , Wang Changyi , Zhang Xiang , Zhao Jing
Published: September 2023

In the short-term power load prediction, the environmental uncertainty will have an impact on the prediction accuracy and increase the complexity of the prediction. To deal with this problem, the paper proposes a bidirectional gated recurrent unit (BiGRU) network model for and sine cosine optimization algorithm with self-learning strategy and Levy flight (SCASL). With real power load data as a data set, high correlation parameters are selected through the Pearson correlation coefficient analysis as input, using the SCASL algorithm and nonlinear weight factor. Finally, the key time points in capturing the historical information of the load changes are established according to the optimization parameters, and BiGRU model is used to learn to predict its accuracy. The experimental results show that the MAPE (Mean Absolute Percentage Error) and RMSE (Root Mean Square Error) of BiGRU model are better than the comparison model gated recurrent unit (GRU) network model. The final results show that the prediction accuracy of the power load system has been significantly improved.
Real-time measurement and compensation based on iGPS for industrial robotic pose accuracy
Authors: Shi Feng , Sun Nianjun , Du Zhaocai , Liu Liming
Published: September 2023

In order to satisfy the requirements of industrial robotic pose accuracy in the operation process, measurement and compensation methods based on iGPS (indoor Global Positioning System) are proposed. An iGPS measuring network is established by solving transformation relations between robotic coordinates and iGPS coordinate, setting up measuring field and calibrating external parameters of transmitters. According to the measured values of iGPS, pose accuracies are calculated, and robotic poses are compensated by modifying command pose and secondary motion fine-tuning respectively. Experiments are designed to verify the measurement and compensation methods. The robotic poses of pre and post compensation are depicted based on 30 successive motion cycles. The pose accuracies are calculated and the effects of the two compensation methods are compared. Experimental results show that the robotic pose accuracies are greatly improved by using the proposed methods, and the real-time compensation method of secondary motion fine-tuning has better compensation effect, which proves the feasibility and effectiveness of the real-time measurement and compensation method based on iGPS.
Development and application research of startup failure and operation failure model of emergency diesel generator in nuclear power plants
Authors: Yang Xiaohu , Qing Chen , Yu Na , Zhang Yanpeng , Cheng Bin
Published: September 2023

In order to fully grasp the law of startup failure and operation failure of emergency diesel generator in nuclear power plants, this paper first presents the development method of integrated fault model for emergency diesel generator startup failure and operation failure on the basis of fully integrating the existing mature fault tree analysis methods. Then, taking a certain type of Emergency diesel generator as an example, a complete startup failure and operation failure model was developed, and qualitative analysis and quantitative evaluation were carried out on the basis of the model, which verified the accuracy and applicability of the model development method. Finally, this paper puts forward the qualitative analysis and quantitative evaluation results based on model, which are directly used in the basic application scheme of equipment safeguard measures and the advanced application scheme of dynamic risk assessment and long-term trend monitoring of emergency diesel generator sets based on model + data driven by emergency diesel generator sets. Through the advanced application solution, users can identify dynamic high-risk defects and long-term reliability management weaknesses in advance, and formulate effective short-term fault elimination and long-term fault prevention measures in time to avoid the consequences of startup failure and operation failure. The above research results have important practical significance for the continuous improvement of the startup reliability and operation reliability of emergency diesel generator in nuclear power plants.
Thermal simulation analysis of power module of combined converter for metro vehicle
Authors: Zhang Junfeng , Chen Yutong , Zhang Liwei
Published: September 2023

In order to reduce the occupancy space and equipment cost of the on-board converter, a combined traction-auxiliary converter for subway vehicles is proposed in this paper. The power loss of the main traction converter module (MCM) and the auxiliary converter module (ACM) was calculated according to the speed and power variation of the vehicle running between five consecutive stations, and the flow rate of cooling air was calculated through the heat balance theory. The air volume of MCM and ACM and the plate temperature of the radiator are analysed by step method. Then, according to the instantaneous maximum temperature of the radiator obtained by simulation and the thermal parameters of the IGBT module, the junction temperature of the IGBT and diode chips is calculated by means of the junction temperature equivalent circuit. The results show that the plate temperature of the heat sink and junction temperature meet the design requirements. The design and thermal simulation method in this paper provide theoretical reference for the design of railway vehicle converters.
An experimental study on the mechanics and control of SMA-actuated bioinspired needle
Authors: Acharya Sharad Raj , Hutapea Parsaoran
Published: September 2023

Active needles demonstrate improved accuracy and tip deflection compared to their passive needle counterparts, a crucial advantage in percutaneous procedures. However, the ability of these needles to effectively navigate through tissues is governed by needle-tissue interaction, which depends on the tip shape, the cannula surface geometry, and the needle insertion method. In this research, we evaluated the effect of cannula surface modifications and the application of a vibrational insertion technique on the performance of shape memory alloy (SMA)-actuated active needles. These features were inspired by the mosquito proboscis’ unique design and skin-piercing technique that decreased the needle tissue interaction force, thus enhancing tip deflection and steering accuracy. The bioinspired features, i.e., mosquito-inspired cannula design and vibrational insertion method, in an active needle reduced the insertion force by 26.24% and increased the tip deflection by 37.11% in prostate-mimicking gel. In addition, trajectory tracking error was reduced by 48%, and control effort was reduced by 23.25%, pointing towards improved needle placement accuracy. The research highlights the promising potential of bioinspired SMA-actuated active needles. Better tracking control and increased tip deflection are anticipated, potentially leading to improved patient outcomes and minimized risk of complications during percutaneous procedures.
Proper choice of hyperparameters in reservoir computing of chaotic maps
Authors: Chen Wei , Gao Jian , Yan Zixiang , Xiao Jinghua
Published: September 2023

Reservoir computing (RC) are powerful to learn and predict dynamical behaviors. However, it has been found that both the reservoir size and the hyperparameters can greatly affect the learning ability of RC on dynamical systems, the mechanism of which still remains unclear. This paper discusses the influence of hyperparameters of RC with different sizes of reservoir on learning typical chaotic maps. An analytic method is purposed to obtain the hyperparameters that can exhibit better learning ability of RC by analyzing high order derivatives of the error loss function. In the case of RC with one or two nodes, the well-performing hyperparameters are analytically obtained for learning the logistic map, which are consistent with numerical results. The analytic method also shows its ability in RC with multiple nodes to learn singer and sine chaotic maps. This work provides deeper insight in learning and predicting behaviors of RC as well as presents guidance for the selection of hyperparameters of RC to learn chaotic systems.
3D bioprinted endothelial cell-microglia coculture for diabetic retinopathy modeling
Authors: Wu Haixiang , Xu Fangcheng , Luo Yunfang , Zhang Yibao , Tang Min
Published: September 2023

Diabetic retinopathy (DR) is a common diabetes complication leading to vision impairment or blindness due to retinal vasculature alterations. Hyperglycemia induces structural alterations, inflammation, and angiogenic factor upregulation. Current treatments targeting vascular endothelial growth factor are insufficient for approximately 20% of DR patients, necessitating alternative approaches. Microglia (MG), essential for retinal homeostasis, remains underexplored in DR. This study used digital light processing bioprinting to construct a 3D coculture model of endothelial cells (ECs) and MG under varying glucose conditions, with a hydrogel stiffness of 4.6–7.1 kPa to mimic the extracellular matrix property of retina plexiform. Our results showed that high glucose levels influenced both EC and microglial phenotypes, gene expression, and angiogenic potential. Increasing glucose from 5 mM to 25 mM reduces drug efficacy by 17% for Aflibercept in EC monoculture, and 25% and 30% for Aflibercept and Conbercept in EC-MG coculture, respectively, suggesting that diabetic condition and MG presence could interfere with drug responses. In conclusion, our findings emphasize the importance of cellular interactions and microenvironmental factors in DR therapy, aiming to identify novel strategies and improve understanding of MG’s role in disease pathogenesis.
Magnetic field assisted stabilization of circular double wall domain lattice in oxidized Fe3GeTe2 flakes
Authors: Pappas P , Georgopoulou-Kotsaki E , Lintzeris A , Dimoulas A
Published: September 2023

The family of 2D ferromagnets is in the center of research for novel spintronics applications. Among the various 2D ferromagnets, Fe3GeTe2 has drawn significant attention since it combines a high Curie temperature with a van der Waals structure, which allows easy exfoliation, and a high spin polarization/large spin–orbit coupling. The presence of interfacial DMI in 2D ferromagnets have a significant impact on the behavior of magnetic domain walls, which are fundamental in magnetic memory and logic devices. By controlling the interfacial DMI, it is possible to manipulate the motion of domain walls and the magnetic domain configuration, which is essential for the development of efficient and reliable magnetic devices. In this study, we investigate the effect of an, inversion symmetry breaking, oxidized layer on the magnetic domain structure of Fe3GeTe2 flakes due to the emergence of interfacial DMI. By combining magneto-optical Kerr effect microscopy images and micromagnetic simulations, we study the formation of a circular double wall (CDW) domain lattice in oxidized flakes under specific field cooling and magnetic field sweeping protocols. Their formation is attributed to a competition between the exchange interaction both symmetric and antisymmetric (associated to interfacial DMI), magnetocrystalline anisotropy and the external magnetic field. The CDW domains have a diameter of several microns, a magnetic structure resembling that of a skyrmionium and are arranged in regular lattice that survives thermal fluctuations close to T
c. Our results suggest that these CDW domains transition to Néel type skyrmions after a magnetic field threshold. These findings could have important implications for the design and optimization of 2D ferromagnetic materials for spintronic applications.
Enhancing mechanical properties of cellular core sandwich panels: a review of topological parameters and design improvements
Authors: Charkaoui Assil , Hassan Noha M , Bahroun Zied
Published: September 2023

Sandwich panels’ exceptional mechanical properties and low density, owing to their multifunctional characteristics and innovative design, made them a popular choice in numerous industries. Sandwich panels with cellular cores are known for their exceptional energy absorption properties, which make them effective energy absorbers for high-impact scenarios such as accidents or explosions. For advancing research on sandwich panels, it is vital to develop innovative designs that can enhance their energy absorption and flexural stiffness. This review outlines the most essential topological parameters that influence the mechanical properties of cellular core structures. This paper gives insight into recent advancements related to optimizing sandwich panel structures for various engineering applications. The topological parameters investigated by researchers include core structure, thickness, number of layers, and material. The choice of core material governs the overall mechanical behavior of the panel. In this paper, various structures, including foam, honeycomb, lattice, corrugated, bioinspired, and various materials, are compared. Functionally graded structures were also explored in the literature as they can significantly optimize the response of sandwich panels in high and low-velocity impact applications. Similarly, a multi-layered core structure can enhance the total stiffness and specific energy absorption of the panel.
Board Processes and Performance: The Impact of Directors’ Social and Human Capital
Authors: Huse Morten
Published: September 2023

What do we know about actual board behavior and board performance? How can we develop our knowledge about board processes and board members’ capabilities? As a research field grows into maturity, we learn to see nuances, and the vocabulary used becomes richer and more detailed. However, the development of a consistent and nuanced language in research about board processes and performance is lagging behind.

How have research streams and individual scholars influenced how we do research today, and why are these stories not included in most of the published literature reviews on this topic? What distinguishes research about boards and governance from various disciplines? How do we find research about board processes and board capital, and how has groundbreaking research on the human side of corporate governance developed? Groundbreaking research of Myles Mace was conducted more than half a decade ago, and we need to understand what has taken place after the seminal 1989 contribution of Zahra and Pearce. Research about actual board behavior and processes were not for decades published in leading management and strategy journals.

Most published research about board processes and board capital is formulaic, leans on proxies rather than direct observation, and has only incremental if any practical contributions. A message is thus that we should strive for more groundbreaking studies that challenge existing knowledge and practice, including our research practice. A research agenda about board processes and board capital should be influenced by some of the following suggestions:

• It should go beyond formulaic and incremental studies. We should challenge existing wisdom and practice and search for alternative ways of doing research.

• It should include more processual studies rather than archival data studies using proxies.

• We should learn from the scholars doing groundbreaking research before us.

• We should learn by comparing experiences from various types of organizations.

• We must include lessons and publications not found in leading English-language journals.

• We should apply a sharing philosophy and a programmatic approach in which we as researchers contribute to developing future generations of scholars.
Structural Equation Modeling
Authors: Wooldredge John
Published: September 2023

Structural Equation Modeling (SEM) is a powerful quantitative tool for theory testing with the ability to generate latent variables that more closely approximate theoretical constructs and parsing out the causal effects (both direct and indirect) versus spurious relationships between them. The roots of SEM date back to the early 20th century, with the developments of Factor Analysis and Path Analysis, but it was not until the second half of the 20th century that CFA developed, and not until the late 20th century that these methods were extended to analyses of both continuous and categorical independent and dependent variables. Data requirements are more demanding for SEM applications relative to single-equation models with observed variables, and users must understand the limitations of both their data and conceptual model (the latter related to model “identification”). SEM applications in criminology have expanded considerably during the 21st century, although its use remains rare compared to other fields. A substantive understanding of the topic is critical for proper model building and model refinement in SEM, and the ability to assess both global fit (for the entire model) and local fit (for specific parameter estimates) is essential for a full evaluation of multi-equation systems. Aside from the more general applications of SEM, it provides one of the most useful methods for studying individual change over time through Latent Growth Curves. SEM is a rigorous method for both theory testing and policy evaluation.
School Choice Policies in Postapartheid South Africa
Authors: Ndimande Bekisizwe S.
Published: September 2023

School choice is a fairly new phenomenon among Black communities in postapartheid South Africa. “Choice” has historically been state-determined; in other words, parents were instructed where to send their children to school based on race and based on the urban/rural homeland division of Black South Africans. Even after 1994, the new and democratically elected government gave very little direction to schools or school districts as to school choice for the purpose of desegregating public schools; there was no bussing, for example, as in the United States when desegregation started in the 1960s. Nor was there a strong rezoning policy that would force White public schools to give Black students access to White schools. In theory and according to the law, parents could choose to send their children to any school regardless of race. In practice, White schools determined who gained access to their schools through self-created policies based on high tuition fees, exclusive language policies, and self-defined “catchment areas” from which students would be chosen. Together, these strategies effectively excluded the Black poor, even though it provided access to the small numbers of Black middle class parents in the mainly English-medium White schools.
Women in Kenya
Authors: Hepburn Sacha
Published: September 2023

Women have played diverse and critical roles in Kenya’s social, cultural, economic, and political history. Archaeological and ethnographic sources suggest how gender shaped culture, social interactions, production, and consumption in hunter-gatherer, early pastoralist, and Iron Age societies. Gender divisions of labor were flexible, with women engaging in gathering, hunting, care of livestock, domestic labor, and production of crafts and metalwork. During the 15th to 18th centuries, societies were organized by gendered and generational hierarchies, and women played a significant role in agriculture and trade. Rates of unfree labor increased significantly, and women and girls were particularly vulnerable to enslavement and pawning within the African slave systems of the interior and Islamic slave system of the coast. The 19th century brought change and upheaval, including the expansion of Islam and Christian missionary activity, ecological crises, and British occupation. The century also witnessed a dramatic increase in demand for female slaves for domestic and foreign markets. Under British colonial rule, women’s roles and status were circumscribed. Colonialism promoted a model of gender which relegated women to the domestic sphere and strengthened indigenous patriarchy. Women found their access to land and resources steadily eroded, even though their labor enabled the broader colonial capitalist system to function. They channeled their frustrations into labor protest, nationalist politics, and armed struggle. Independence brought change and continuity for Kenyan women and girls. There was a gradual expansion of women’s rights and opportunities in education and employment, alongside the endurance of widespread gender and socioeconomic inequality. Overall, there was no one experience for Kenyan women in any period: women’s experiences varied depending on their age, ethnicity, religion, culture, and status as free or enslaved persons; where some women found widening opportunities, others faced new and enduring constraints; and when some railed against gendered and generational authority structures, others enforced them.
The Dependency Research Programme: Its Latin American Origins and Global Contemporary Applications
Authors: Palestini Stefano
Published: September 2023

The dependency research program (DRP) provides an understanding of global capitalism from the perspective of postcolonial societies. Central concepts in international studies, such as the core/periphery, unequal exchange, and dependent development, were developed by scholars working from the DRP perspective. Its core assumptions were shaped by the intellectual and political debates among critical Latin American scholars working in the 1960s and 1970s—a period marked by deep processes of sociopolitical change. Although the origins of the DRP are rooted in Latin America, its development and influence is global in scope. Its ideas and concepts inspired other approaches and fields of research such as the World System Theory and the studies on the developmental state, and its core assumptions informed the works of researchers in Africa, Asia, and Europe. Since the early 2000s and especially after the global financial crisis of 2008, new works have been published drawing on the insights of the DRP. Most of this scholarship has focused on topics such as dependency and global production networks, dependent financialization, dependency and European integration, and the new situations of dependency brought about by the rise of China. Although the DRP has been criticized for lacking clear microfoundations, this article makes the case that by bringing sociopolitical coalitions to the fore and by identifying specific mechanisms of dependency, the DRP will continue being a viable and vibrant approach to explain global inequalities in the contemporary global political economy.
Antislavery and Abolition in the Spanish American Mainland
Authors: Echeverri Marcela
Published: September 2023

One of the major changes that was produced by the wars of independence and the consequent foundation of new republics across the Spanish American mainland during the first five decades of the 19th century was the abolition of slavery. The history of the abolition of slavery in this region illustrates how economic, political, and social factors were entwined in the Spanish American revolutions as processes that were at once embedded in the broader imperial and transimperial dynamics of the 19th century, yet also singular in the origins and consequences that the end of slavery had in that region due to its connection to republican formation and the integration of African-descended people in legal and political terms.
The mental health impact of the COVID-19 pandemic on older adults: a systematic review and meta-analysis
Authors: Schäfer Sarah K , Lindner Saskia , Kunzler Angela M , Meerpohl Jörg J , Lieb Klaus
Published: September 2023

Background

Early in the COVID-19 pandemic, many experts pointed to potential adverse mental health effects for older adults. By contrast, many studies in young to middle-aged adults found older age to be associated with reduced mental burden. However, a systematic review on older adults is missing.

Objectives

To comprehensively assess the pandemic’s mental health impact on older adults.

Data sources

We searched nine databases from December 2019 to April 2022.

Study selection

We included longitudinal and repeated cross-sectional studies assessing pre- and/or peri-pandemic mental distress and/or positive mental health indicators (e.g. wellbeing) on at least two occasions.

Data synthesis

We identified 108 studies comprising 102,136 participants (≥60 years). After removal of outliers, there was a small increase in mental distress from pre-to-peri-pandemic assessments, standardised mean difference (SMD) = 0.10, 95% confidence interval (CI) [0.01, 0.18]. Furthermore, a small peri-pandemic decrease in anxiety symptoms was observed, whereas other symptoms remained unchanged. For positive mental health indicators, wellbeing and quality of life showed an initial decrease, whereas overall positive mental health increased during the pandemic, SMD = 0.08, 95% CI [0.01, 0.15]. Being female was related to larger peri-pandemic increases in mental distress.

Conclusions

Based on many studies, this review demonstrated small decreases in mental health during early stages of the pandemic in older adults, with evidence for later recovery. These findings are similar to those for younger adults and correct earlier claims that older adults are at particular risk for negative mental health consequences. The results ask for further research into resilience and adaptation processes in older adults.
Cooking skills modify the association between oral health and mortality
Authors: Tani Yukako , Yamamoto Takafumi , Kusama Taro , Kinugawa Anna , Aida Jun , Fujiwara Takeo , Kondo Katsunori
Published: September 2023

Poor oral health has been linked to an increased risk of mortality. People with good cooking skills may be able to cope with problems caused by oral dysfunction, such as restricted food choice. This study investigated whether cooking skills modified the association between oral health status and mortality. A 3-year follow-up was conducted among participants of the Japan Gerontological Evaluation Study, a population-based cohort study of Japanese adults aged 65–101 years. Oral health assessment comprised number of teeth and three oral functions (awareness of swallowing difficulty, decline in masticatory function, and dry mouth). Cooking skills were assessed using a valid scale adapted for Japanese participants. Mortality from 2016 to 2019 was analysed for 10,121 respondents. Cox regression models were used to estimate hazard ratios for mortality risk adjusting for potential confounders, including sociodemographic factors and health status. During the follow-up, there were 488 deaths (4.8% of all participants). Both fewer teeth and poor oral function were associated with a greater mortality risk. Cooking skills modified the association only for oral function. Stratification by cooking skill score showed that the hazard ratios for ≥2 oral difficulties (vs. none) was 2.06 (95% confidence interval: 1.43–2.96) among those with low cooking skills and 1.25 (95% confidence interval: 0.92–1.71) among those with high cooking skills after adjusting for potential confounders. Improving cooking skills may be key to mitigating health risks owing to poor oral functions.
Placental insufficiency and heavier placentas in sheep after suppressing CXCL12/CXCR4 signaling during implantation
Authors: Ashley Ryan L , Trigo Elisa M , Ervin Jacqueline M
Published: September 2023

During implantation, trophoblast cell invasion and differentiation is predominantly important to achieving proper placental formation and embryonic development. The chemokine, C-X-C motif chemokine ligand 12 (CXCL12) working through its receptor C-X-C motif chemokine receptor 4 (CXCR4) is implicated in implantation and placentation but precise roles of this axis are unclear. Suppressing CXCL12/CXCR4 signaling at the fetal-maternal interface in sheep reduces trophoblast invasion, disrupts uterine remodeling, and diminishes placental vascularization. We hypothesize these negative impacts during implantation will manifest as compromised fetal and placental growth at midgestation. To test, on day 12 postbreeding, osmotic pumps were surgically installed in 30 ewes and delivered intrauterine CXCR4 inhibitor or saline for 7 or 14 days. On day 90, fetal/maternal tissues were collected, measured, weighed, and maternal (caruncle) and fetal (cotyledon) placenta components separated and analyzed. The objectives were to determine if (i) suppressing CXCL12/CXCR4 during implantation results in reduced fetal and placental growth and development and (ii) if varying the amount of time CXCL12/CXCR4 is suppressed impacts fetal/placental development. Fetal weights were similar; however greater placental weight and placentome numbers occurred when CXCL12/CXCR4 was suppressed for 14 days. In caruncles, greater abundance of fibroblast growth factor 2, vascular endothelial growth factor A, vascular endothelial growth factor A receptor 1 (FLT-1), and placental growth factor were observed after suppressing CXCL12/CXCR4. Similar results occurred in cotyledons except less vascular endothelial growth factor in 7 day group and less fibroblast growth factor in 14 day group. Our data underscore the importance of CXCL12/CXCR4 signaling during placentation and provide strong evidence that altering CXCL12-mediated signaling induces enduring placental effects manifesting later in gestation.
Polystyrene micro- and nanoplastics cause placental dysfunction in mice
Authors: Dibbon Katherine C , Mercer Grace V , Maekawa Alexandre S , Hanrahan Jenna , Steeves Katherine L , Ringer Lauren C M , Simpson André J , Simpson Myrna J , Baschat Ahmet A , Kingdom John C , Macgowan Christopher K , Sled John G , Jobst Karl J , Cahill Lindsay S
Published: September 2023

Maternal exposure to microplastics and nanoplastics has been shown to result in fetal growth restriction in mice. In this study, we investigated the placental and fetal hemodynamic responses to plastics exposure in mice using high-frequency ultrasound. Healthy, pregnant CD-1 dams were given either 106 ng/L of 5 μm polystyrene microplastics or 106 ng/L of 50 nm polystyrene nanoplastics in drinking water throughout gestation and were compared with controls. Maternal exposure to both microplastics and nanoplastics resulted in evidence of placental dysfunction that was highly dependent on the particle size. The umbilical artery blood flow increased by 48% in the microplastic-exposed group and decreased by 25% in the nanoplastic-exposed group compared to controls (p < 0.05). The microplastic- and nanoplastic-exposed fetuses showed a significant decrease in the middle cerebral artery pulsatility index of 10% and 13%, respectively, compared to controls (p < 0.05), indicating vasodilation of the cerebral circulation, a fetal adaptation that is part of the brain sparing response to preserve oxygen delivery. Hemodynamic markers of placental dysfunction and fetal hypoxia were more pronounced in the group exposed to polystyrene nanoplastics, suggesting nanoplastic exposure during human pregnancy has the potential to disrupt fetal brain development, which in turn may cause suboptimal neurodevelopmental outcomes.
Grey matter heterotopia subtypes show specific morpho-electric signatures and network dynamics
Authors: Vermoyal Jean-Christophe , Hardy Delphine , Goirand-Lopez Lucas , Vinck Antonin , Silvagnoli Lucas , Fortoul Aurélien , Francis Fiona , Cappello Silvia , Bureau Ingrid , Represa Alfonso , Cardoso Carlos , Watrin Françoise , Marissal Thomas , Manent Jean-Bernard
Published: September 2023

Grey matter heterotopia (GMH) are neurodevelopmental disorders associated with abnormal cortical function and epilepsy. Subcortical band heterotopia (SBH) and periventricular nodular heterotopia (PVNH) are two well-recognized GMH subtypes in which neurons are misplaced, either forming nodules lining the ventricles in PVNH, or forming bands in the white matter in SBH. Although both PVNH and SBH are commonly associated with epilepsy, it is unclear whether these two GMH subtypes differ in terms of pathological consequences or, on the contrary, share common altered mechanisms.

Here, we studied two robust preclinical models of SBH and PVNH, and performed a systematic comparative assessment of the physiological and morphological diversity of heterotopia neurons, as well as the dynamics of epileptiform activity and input connectivity. We uncovered a complex set of altered properties, including both common and distinct physiological and morphological features across heterotopia subtypes, and associated with specific dynamics of epileptiform activity. Taken together, these results suggest that pro-epileptic circuits in GMH are, at least in part, composed of neurons with distinct, subtype-specific, physiological and morphological properties depending on the heterotopia subtype.

Our work supports the notion that GMH represent a complex set of disorders, associating both shared and diverging pathological consequences, and contributing to forming epileptogenic networks with specific properties. A deeper understanding of these properties may help to refine current GMH classification schemes by identifying morpho-electric signatures of GMH subtypes, to potentially inform new treatment strategies.
Visual, delay, and oculomotor timing and tuning in macaque dorsal pulvinar during instructed and free choice memory saccades
Authors: Schneider Lukas , Dominguez-Vargas Adan-Ulises , Gibson Lydia , Wilke Melanie , Kagan Igor
Published: September 2023

Causal perturbations suggest that primate dorsal pulvinar plays a crucial role in target selection and saccade planning, though its basic neuronal properties remain unclear. Some functional aspects of dorsal pulvinar and interconnected frontoparietal areas—e.g. ipsilesional choice bias after inactivation—are similar. But it is unknown if dorsal pulvinar shares oculomotor properties of cortical circuitry, in particular delay and choice-related activity. We investigated such properties in macaque dorsal pulvinar during instructed and free-choice memory saccades. Most recorded units showed visual (12%), saccade-related (30%), or both types of responses (22%). Visual responses were primarily contralateral; diverse saccade-related responses were predominantly post-saccadic with a weak contralateral bias. Memory delay and pre-saccadic enhancement was infrequent (11–9%)—instead, activity was often suppressed during saccade planning (25%) and further during execution (15%). Surprisingly, only few units exhibited classical visuomotor patterns combining cue and continuous delay activity or pre-saccadic ramping; moreover, most spatially-selective neurons did not encode the upcoming decision during free-choice delay. Thus, in absence of a visible goal, the dorsal pulvinar has a limited role in prospective saccade planning, with patterns partially complementing its frontoparietal partners. Conversely, prevalent visual and post-saccadic responses imply its participation in integrating spatial goals with processing across saccades.
Cortical and subcortical contributions to non-motor inhibitory control: an fMRI study
Authors: Pan Xin , Wang Zhaoxin
Published: September 2023

Inhibition is a core executive cognitive function. However, the neural correlates of non-motor inhibitory control are not well understood. We investigated this question using functional Magnetic Resonance Imaging (fMRI) and a simple Count Go/NoGo task (n = 23), and further explored the causal relationships between activated brain regions. We found that the Count NoGo task activated a distinct pattern in the subcortical basal ganglia, including bilateral ventral anterior/lateral nucleus of thalamus (VA/VL), globus pallidus/putamen (GP/putamen), and subthalamic nucleus (STN). Stepwise regressions and mediation analyses revealed that activations in these region(s) were modulated differently by only 3 cortical regions i.e. the right inferior frontal gyrus/insula (rIFG/insula), along with left IFG/insula, and anterior cingulate cortex/supplementary motor area (ACC/SMA). The activations of bilateral VA/VL were modulated by both rSTN and rIFG/insula (with rGP/putamen as a mediator) independently, and the activation of rGP/putamen was modulated by ACC/SMA, with rIFG/insula as a mediator. Our findings provide the neural correlates of inhibitory control of counting and causal relationships between them, and strongly suggest that both indirect and hyperdirect pathways of the basal ganglia are involved in the Count NoGo condition.
Top-down influence of areas 21a and 7 differently affects the surround suppression of V1 neurons in cats
Authors: Yu Hao , Chen Shunshun , Ye Zheng , Zhang Qiuyu , Tu Yanni , Hua Tianmiao
Published: September 2023

Surround suppression (SS) is a phenomenon whereby a neuron’s response to stimuli in its central receptive field (cRF) is suppressed by stimuli extending to its surround receptive field (sRF). Recent evidence show that top-down influence contributed to SS in the primary visual cortex (V1). However, how the top-down influence from different high-level cortical areas affects SS in V1 has not been comparatively observed. The present study applied transcranial direct current stimulation (tDCS) to modulate the neural activity in area 21a (A21a) and area 7 (A7) of cats and examined the changes in the cRF and sRF of V1 neurons. We found that anode-tDCS at A21a reduced V1 neurons’ cRF size and increased their response to visual stimuli in cRF, causing an improved SS strength. By contrast, anode-tDCS at A7 increased V1 neurons’ sRF size and response to stimuli in cRF, also enhancing the SS. Modeling analysis based on DoG function indicated that the increased SS of V1 neurons after anode-tDCS at A21a could be explained by a center-only mechanism, whereas the improved SS after anode-tDCS at A7 might be mediated through a combined center and surround mechanism. In conclusion, A21a and A7 may affect the SS of V1 neurons through different mechanisms.
Assessing the effects of a drought experiment on the reproductive phenology and ecophysiology of a wet tropical rainforest community
Authors: Vogado Nara , Laurance Susan G , Liddell Michael J , Engert Jayden E , Wurster Christopher M , Schiffer Michele , Thompson Andrew , Nichols Cassandra , Cernusak Lucas A
Published: September 2023

Climate change is expected to increase the intensity and occurrence of drought in tropical regions, potentially affecting the phenology and physiology of tree species. Phenological activity may respond to a drying and warming environment by advancing reproductive timing and/or diminishing the production of flowers and fruits. These changes have the potential to disrupt important ecological processes, with potentially wide-ranging effects on tropical forest function. Here, we analysed the monthly flowering and fruiting phenology of a tree community (337 individuals from 30 species) over 7 years in a lowland tropical rainforest in northeastern Australia and its response to a throughfall exclusion drought experiment (TFE) that was carried out from 2016 to 2018 (3 years), excluding approximately 30% of rainfall. We further examined the ecophysiological effects of the TFE on the elemental (C:N) and stable isotope (δ13C and δ15N) composition of leaves, and on the stable isotope composition (δ13C and δ18O) of stem wood of four tree species. At the community level, there was no detectable effect of the TFE on flowering activity overall, but there was a significant effect recorded on fruiting and varying responses from the selected species. The reproductive phenology and physiology of the four species examined in detail were largely resistant to impacts of the TFE treatment. One canopy species in the TFE significantly increased in fruiting and flowering activity, whereas one understory species decreased significantly in both. There was a significant interaction between the TFE treatment and season on leaf C:N for two species. Stable isotope responses were also variable among species, indicating species-specific responses to the TFE. Thus, we did not observe consistent patterns in physiological and phenological changes in the tree community within the 3 years of TFE treatment examined in this study.
Unravelling the intricacies of left ventricular haemodynamic forces: age and gender-specific normative values assessed by cardiac MRI in healthy adults
Authors: Yang Wenjing , Wang Yining , Zhu Leyi , Xu Jing , Wu Weichun , Zhou Di , Sirajuddin Arlene , Arai Andrew E , Zhao Shihua , Lu Minjie
Published: September 2023

Aims

Haemodynamic forces (HDFs) provided a feasible method to early detect cardiac mechanical abnormalities by estimating the intraventricular pressure gradients. The novel advances in assessment of HDFs using routine cardiac magnetic resonance (CMR) cines shed new light on detection of preclinical dysfunction. However, definition of normal values for this new technique is the prerequisite for application in the clinic.

Methods and results

A total of 218 healthy volunteers [38.1 years ± 11.1; 111 male (50.9%)] were recruited and underwent CMR examinations with a 3.0T scanner. Balanced steady state free precession breath hold cine images were acquired, and HDF assessments were performed based on strain analysis. The normal values of longitudinal and transversal HDF strength [root mean square (RMS)] and ratio of transversal to longitudinal HDF were all evaluated in overall population as well as in both genders and in age-specific groups. The longitudinal RMS values (%) of HDFs were significantly higher in women (P < 0.05). Moreover, the HDF amplitudes significantly decreased with ageing in entire heartbeat, systole, diastole, systolic/diastolic transition, and diastolic deceleration, while increased in atrial thrust. In multivariable linear regression analysis, age, heart rate, and global longitudinal strain emerged as independent predictors of the amplitudes of longitudinal HDFs in entire heartbeat and systole, while left ventricular end-diastole volume index was also independently associated with longitudinal HDFs in diastole and diastolic deceleration (P < 0.05 for all).

Conclusion

Our study provided comprehensive normal values of HDF assessments using CMR as well as presented with specific age and sex stratification. HDF analyses can be performed with excellent intra- and inter-observer reproducibility.
The Alchemy of the Right to Life during the Conduct of Hostilities: A Normative Approach to Operationalizing the ‘Supreme Right’
Authors: Waschefort Gus
Published: September 2023

The prevailing approach to the application of the right to life during the conduct of hostilities holds that the arbitrariness of loss of life in terms of international human rights law (IHRL) is determined by compliance with international humanitarian law (IHL). Through application of the interpretive principle of systemic integration, an alternative ‘normative approach’ is advanced. The normative approach is premised on a contextual consideration of the normative content and underlying values of the right to life rather than on the more mechanical approaches to its interpretation. The outcome reached that is based on this approach has two profound distinctions to that of the prevailing approach: (i) not all loss of life where IHL was not strictly complied with is ipso jure arbitrary and, conversely, (ii) at times, compelling factors necessitate a recalibration of arbitrariness along a spectrum between IHRL and IHL, with the result that loss of life may amount to arbitrary deprivation of life even when IHL is fully complied with. In the context of quintessential military operations, a two-pronged normative test is advanced to determine the circumstances in which non-compliance with IHL will result in arbitrary deprivation of life.
Following in the parents’ footsteps? Using sibling data to analyse the intergenerational transmission of social (dis)advantage in Scotland
Authors: Iannelli Cristina , Breen Richard , Duta Adriana
Published: September 2023

This study provides new evidence about the extent to which individual occupational status is determined by family of origin (ascription) and by educational attainment (achievement). Using linked administrative data from the Scottish Longitudinal Study, we measure intergenerational mobility using sibling correlations and we assess the effect of siblings’ education on their occupational status by examining between- and within-sibling differences. We show that about 36 per cent of siblings’ variation in occupational status in Scotland is attributable to shared family factors. Our observed measures of family background explain about 40 per cent of the shared family effect, meaning that family-based advantages in the Scottish labour market largely arise from unmeasured factors. We also find that siblings’ educational attainment accounts for 80 per cent of the variation between families in occupational status. While this may suggest that the Scottish labour market is highly meritocratic, previous research that showed a very strong family effect on educational attainment leads us to a different interpretation, namely that social inequalities in education are the main mechanism through which inequalities between families are reproduced (and perhaps legitimated) in the Scottish labour market.