Transition Area Research Articles

BONE REMODELLING PREDICTION FOR IMPROVED POROUS IMPLANT DESIGN

AbstractObjectivesYoung patients receiving metallic bone implants after surgical resection of bone cancer require implants that last into adulthood, and ideally life-long. Porous implants with similar stiffness to bone can promote bone ingrowth and thus beneficial clinical outcomes. A mechanical remodelling stimulus, strain energy density (SED), is thought to be the primary control variable of the process of bone growth into porous implants. The sequential process of bone growth needs to be taken into account to develop an accurate and validated bone remodelling algorithm, which can be employed to improve porous implant design and achieve better clinical outcomes.MethodsA bone remodelling algorithm was developed, incorporating the concept of bone connectivity (sequential growth of bone from existing bone) to make the algorithm more physiologically relevant. The algorithm includes adaptive elastic modulus based on apparent bone density, using a node-based model to simulate local remodelling variations while alleviating numerical checkerboard problems. Strain energy density (SED) incorporating stress and strain effects in all directions was used as the primary stimulus for bone remodelling. The simulations were developed to run in MATLAB interfacing with the commercial FEA software ABAQUS and Python. The algorithm was applied to predict bone ingrowth into a porous implant for comparison against data from a sheep model.ResultsThe accuracy of the predicted bone remodelling was verified for standard loading cases (bending, torsion) against analytical calculations. Good convergence was achieved. The algorithm predicted good bone remodelling and growth into the investigated porous implant. Using the standard algorithm without connectivity, bone started to remodel at locations unconnected to any bone, which is physiologically implausible. The implementation of bone connectivity ensures the gradual process of bone growth into the implant pores from the sides. The bone connectivity algorithm predicted that the full remodelling required more time (approximately 50% longer), which should be considered when developing post-surgical rehabilitation strategies for patients. Both algorithms with and without bone connectivity implementation converged to same final stiffness (less than 0.01% difference). Almost all nodes reached the same density value, with only a limited number of nodes (less than 1%) in transition areas with a strong density gradient having noticeable differences.ConclusionsAn improved bone remodelling algorithm based on strain energy density that modelled the sequential process of bone growth has been developed and tested. For a porous metallic bone implant the same final bone density distribution as for the original adaptive elasticity theory was predicted, with a slower and more fidelic process of growth from existing surrounding bone into the porous implant.Declaration of Interest(b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Modelling the compound floods upon combined rainfall and storm surge events in a low-lying coastal city

Low-lying coastal cities are highly vulnerable to compound floods, which may result from a simultaneous occurrence of storm surges and heavy rainfall. Systematic numerical analysis is essential for projecting flood scenarios upon compound events. In this study, a coupled model that integrates the 1D drainage module with the 2D overland flow module is developed and validated by taking Macau as the study area. The joint cumulative probability distribution between rainfall and storm tide are derived based on the historical typhoon data. The flood hazards are projected under designed scenarios, and an investigation is conducted on the backflow processes through drainage system and effectiveness of installing tide gates. The flood zones are delineated and the contributions of rainfall and storm tide to floods are analyzed. Storm surge exerts a greater influence on the maximum inundation depth in the western Macau Peninsula than heavy precipitation does. As the peak tidal level increases from a 10-year to a 200-year return period, the increments of flooded area ratio to the total land area are approximately 19 %. The backflows through underground drainage system could expand the tide affected area during storm events, as indicated by the backflows in the pipe 1.4 km away from the coastal boundary. By installing tide gates, backflows could be greatly eliminated in the corresponding pipes. The inundation area in the compound flood scenario is not equal to the superposition of the extents by the individual components. The transition area that is affected by both storm tide and rainfall extends from coast to inland areas under the combined effects. This study is expected to furnish valuable insights for flood risk assessment, flood hazard prevention and mitigation in low-lying coastal cities such as Macau.

External Forcings Caused the Tripole Trend of Asian Precipitation During the Holocene

AbstractTo investigate the evolution of precipitation over Asian continent in the Holocene and the associated mechanisms, we used a set of simulations of the transient climate evolution over the past 21,000 years (TraCE‐21ka), multimodel results from the Paleoclimate Modeling Intercomparison Project Phase 4 (PMIP4), and proxy records in Asia. The TraCE‐21ka results showed a tripole pattern in suborbital‐scale precipitation trends over the Asian continent during the Holocene, with a trend of increase over southern parts of the monsoon regions and arid Central Asia (ACA), and a trend of decline over northern parts of the monsoon regions and their areas of transition with ACA. This tripole pattern was corroborated by proxy records from multiple regions and multimodel results from the PMIP4. Further analysis based on single‐forcing simulations of TraCE‐21ka indicated that influences from different external forcings were different on the Asian precipitation in the main rainy seasons in the Holocene and that their combined effects shaped the tripole pattern. In summer, orbital forcing, by reducing solar radiation in mid‐to‐high latitudes and weakening the land‐sea thermal contrast, has been the dominant factor in the long‐term evolution of precipitation in the monsoon region and West Asia. In winter and spring, changes in meltwater flux played dominant roles in intensifying local water cycle and horizontal moisture advection, which drove the trend of increase in precipitation in ACA. Additionally, changes in greenhouse gas concentration and continental ice sheet forcings both also contribute to the increase in precipitation in ACA.

Influence of rail side lubrication and slip rate dependent effects upon the corrugation on the metro small curve track

For investigating the rail corrugation characteristics of metro small curve track under the combined effect of rail side lubrication and slip rate dependence, by developing a three-dimensional vehicle-track coupling numerical model, the wheel-rail (WR) contact stick-slip (SS) characteristics under different transition areas of rail side lubrication in the presence of corrugation were analyzed. Meantime, on the basis of considering the friction slip rate dependence, the SS vibration characteristics under different rail side lubrication conditions were further analyzed to understand the effect mechanism of rail surface friction characteristics on corrugation. The results show that, when there is rail side lubrication, both inner and outer WR systems have the possibility for SS vibration, and the longitudinal SS vibration intensity is greater than the transverse SS vibration intensity; the SS vibration intensity of the inner WR system is greater than that of the outer WR system, indicating that the inner rail is more susceptible to corrugation and the corrugation is more acute. With the expansion of the rail side lubrication range, the standard deviations of longitudinal and transverse adhesion coefficients decrease, illustrating that the expansion of the lubrication range can reduce the SS vibration intensity of WR system. When the co-effects of rail side lubrication and slip rate dependence are considered, the increase of the rail side lubrication range leads to the increase of standard deviations of adhesion coefficients, which may be related to the enhancement of slip effect induced by the increase of the lubrication range. The introduction of slip rate dependent effect can reduce the standard deviation of the WR adhesion coefficient, which demonstrates that the slip rate dependent effect can ease the degree of SS vibration of WR system, thus reducing the probability of corrugation occurrence caused by the SS vibration.

Spatial path to achieve urban-rural integration development − analytical framework for coupling the linkage and coordination of urban-rural system functions

This study presents a groundbreaking theoretical framework to examine the role of urban-rural system functions (URSFs) in the coordinated development of urban-rural integration (URI). The main emphasis is on the systematic, spatial, and procedural aspects of urban-rural relations (URRs), aiming to rectify the imbalances and deficiencies in URI development. Through multivariate measurement methods, the study evaluates the functional robustness of the urban-rural system (URS) from perspectives of living, production, and ecology, and distinguishes the degree of interaction and coordination. It introduces a spatial path for URI using module combinations and “point-axis” abstract logic. An empirical analysis of China's eastern provinces discloses a noticeable decrease in URS functionality from developed to underdeveloped regions. Although linkage and complementarity between urban and rural areas are significant, mutual promotion and equilibrium between urban and rural production and living functions remain suboptimal. In Shandong Province, the coordination attributes of the three primary URSFs are predominantly characterized by low coordination, an imbalance type of weaker R, and significant urban overshadowing of rural dynamics. Urban-rural synchronous promotion overwhelmingly defines URS functional relationship typologies. The integrated pattern of urban-rural development (URD) after the integration of system functions is a “point-area” feature, gradually expanding the scope from the URI model area, the URI pilot area, and the URI transition area to the URI key area, and shows the spatial structural layout of “two centers, three groups and six circles”. To achieve URI development, comprehensive planning and coordinated promotion of new urbanization and rural revitalization strategies are needed, focusing on micro-level rural regional system issues. The study emphasizes a new model and path for URI development, wherein urban areas support rural development, both develop synchronously, and rural development takes precedence over urban development.

Numerical analysis of impingement characteristics of supercooled large droplets on the surface of a rotating hood

The authors of this study numerically analyze the characteristics of impingement of supercooled large droplets on the surface of the rotating hood of an aircraft. We use the secondary development function of Fluent software to first compare the prevalent models of impinging supercooled large droplets and then develop a modified model to numerically simulate their characteristics of impingement on the surface of a rotating hood in order to examine the effects of the diameter of the droplets, the speed of rotation, and the corresponding velocity of inflow on them. The results showed that the efficiency of the loss of mass of the droplets caused by their splashing and rebounding was low on the top of the cone, while the efficiency of local droplet collection was the highest. The efficiency of mass loss quickly increased, while that of droplet collection sharply decreased in the area of transition from the top to the side. The efficiencies of mass loss and droplet collection were nearly constant on the side of the cone, while that of the latter decreased to zero on the tail of the cone. When the median volumetric diameter of the droplets was increased from 79 to 250 µm, the efficiency of the loss of mass increased by about 15% on the side of the cone, but that of local droplet collection changed only slightly. The efficiency of the loss of mass decreased by about 20%, while that of local droplet collection increased by about 2.6% on the top of the cone under this condition. When the speed of rotation was increased from 1200 to 4300 r/min and the corresponding velocity of inflow was increased from 30 to 140 m/s, the efficiency of mass loss increased by about 15% on the side of the cone, while that of local droplet collection changed little. The efficiency of mass loss on the top of the cone decreased by about 37.5%, while that of local droplet collection increased by about 8% in this case.

Determinants of the urban green spaces management practices in the city of Niamey, Niger

Urban green spaces in the city of Niamey are under the threat of rapid urbanization in the context of climate change. The urban green space management becomes paramount and solicits the stakeholders' participation. Therefore, this study aims to analyze the determinants of the urban green space management practiced by the dwellers in Niamey City. Based on the questionnaire, the multinomial logistic model was applied to the primary data collected from close to 390 randomly selected households. The results show that the variables shade from urban green spaces, gender, household size, education level, monthly income, work status, length of time living in the districts, the status of peripheral areas, status of transitional areas, cost of the management, and plant market are the determinants of the urban green space management practices. These results give a signal to urban managers, and decision-makers on the factors to be addressed for better delivering urban green spaces likely to enhance urban climate resilience.

In the land of tin men? Warrior stelae, mobility, and interaction in western Iberia during the Late Prehistory

The warrior stelae, also called southwestern stelae or western stelae, emerge as one of the most characteristic manifestations of the Bronze Age in Iberia. Since the earliest findings more than a century ago, these monoliths have received great attention from scholars, becoming the subject of an intense debate, without a consensus having been reached on their meaning and sense. A slow but steady trickle of new findings, as well as the implementation of new approaches to their study, has only enriched these discussions in recent years. One of the most successful lines has been the spatial analysis focused on the relationship of these monuments with routes, transit areas, and resources of great value. It is within this line that this article explores the potential relationship that the stelae may have had with a critical mineral resource: the tin ores distributed in western Iberia, which is the highest concentration of this mineral in Europe. To do this, a detailed spatial analysis has been conducted in order to explore if the uneven density of these monuments across western Iberia may be linked with the presence of tin ores or, alternatively, with the control of the routes that allowed the circulation of this mineral by land.

Charting the path towards a long-term knowledge brokerage function: an ecosystems view

Hybrid networks of actors such as policymakers, funders, scholars, and business practitioners are simultaneous producers and consumers of evidence use. While this diversity of evidence use is a strength, it also necessitates greater collaboration among interested parties for knowledge exchange. To address this need, we investigate how ecotones, which are hybrid networks operating in the transitional area between two distinct ecosystems, such as academic research and policy ecosystems, must involve, disseminate, and integrate different types of knowledge. Specifically, our research aims to unpack how an ecotone’s knowledge brokerage function evolves over its lifecycle. This paper presents the findings of a phenomenological investigation involving experts from the policy and academic research ecosystems. The study introduces a three-stage maturity transitions framework that outlines the trajectory of the brokerage function throughout the ecotone’s lifecycle: i. as a service function, ii. a programme-partnership, and iii. a network of networks. The paper contributes to the theory of knowledge brokerage for policy-making. We reflect on our findings and discuss the theoretical contributions within an ecosystem approach and their associated research and policy implications.

Pemanfaatan Limbah FABA (Fly Ash Bottom Ash) dalam Penataan Ruang Komunal Anak di Kampung Nelayan Barombong Kota Makassar

Communal space for children of Biringkassi Barombong fishing village is located in the outer space of residential buildings, namely in the transition zone between land, water and mangrove vegetation. Activities carried out by fishermen children include exploring, playing, increasing sensory to the playground, interacting, expressing and creating. However, some spaces in quality are not yet representative as play spaces. For this reason, it is necessary to arrange materials made from FABA waste that apply environmentally friendly principles. The aspect of efficiency because its use requires lower costs, local material categories, and is resistant to sea water and is very suitable for soil and water conditions in Barombong Fisherman Village. The purpose of national integrated research-based community service activities is to organize the communal space of fishermen's children by applying FABA Waste. The ABCD method is an asset-based community with FABA material as the main element in the arrangement because the material properties are environmentally friendly, easy to modify, and resistant to coastal environmental conditions with an area of 21 m2 can minimize coal waste from burning electricity. The socio-cultural activity space is located in the settlement transition area. The space is set as a children's play space in the natural and built space of the fishermen group. The distribution of these spaces includes ponds, soccer fields, bridges, backyards, and sandbars. The results of service activities in the form of ideas, designs and applications for utilizing FABA (Fly Ash and Bottom Ash) by building children's playgrounds can become prototypes while improving the quality of built environment assets, especially in urban coastal informal settlements.

Volumetric alterations of the hippocampal subfields in major depressive disorder with and without suicidal ideation

Major depressive disorder (MDD) is often accompanied with suicidal ideation (SI). Previous studies suggested that MDD patients who experienced suicidal attempts (SA) exhibited smaller hippocampal volume than those without SA. The hippocampus consists of several subfields that are histologically and functionally unique respectively. However, few studies have been designed to investigate the relationship between suicide and volumetric changes of the hippocampal subfields in MDD. A total of 92 participants, including 24 MDD patients with SI (MDD-SI), 30 MDD patients without SI (MDD-nSI), and 38 healthy controls (HC) were recruited in this study. High-resolution structural magnetic resonance images (MRI) were obtained and analyzed by using the automated hippocampal substructure module in FreeSurfer 7.3.2 Analyses of variance (ANOVA) were performed to obtain hippocampal subfields with significant differences among three groups and then post hoc tests were calculated for inter-group comparisons. Finally, the relationships between volumes of the hippocampal subfields and clinical characteristics were assessed using correlation analyses. The ANOVA revealed significant volumetric differences of the hippocampal subfields among three groups in the bilateral cornu ammonis (CA) 1 head, CA4 body, granule cell layer of the dentate gyrus (GC-ML-DG), molecular layer (ML), the right hippocampus-amygdala transition area (HATA), the right subiculum (Sub) body, and the left CA4 head. Relative to HC, both groups of MDD showed decreased volumes in the CA1 head, CA4, GC-ML-DG head, ML head, and whole hippocampal head of the left hippocampus, the right HATA, and bilateral whole hippocampal body, and whole hippocampus. Meanwhile, the MDD-SI group further exhibited diminished volume in the CA1 head, GC-ML-DG head, ML head, CA4 body, Sub body, and whole hippocampal head of the right hippocampus, as well as bilateral GC-ML-DG body and ML body. Additionally, the MDD-SI group also showed decreased volumes in the right GC-ML-DG body, ML body, and Sub body when compared to MDD-nSI group. However, no significant association was observed between hippocampal subfield volumes and clinical features in MDD. The present findings suggested that SI in MDD might be attributed to subfield abnormalities in the subiculum and DG-dominant circuit of the right hippocampus.

Kajian Analisis Aksesibilitas Transportasi Publik di Kawasan Cipete Raya

This study aims to analyze the accessibility of public transportation in the Cipete Raya transit area which is an active trading area planning area. In this context, smooth mobility is an important factor to maintain a sustainable economic cycle. Therefore, it is important to provide effective public transportation facilities and infrastructure around the area. The method used in this study is space syntax analysis, which is used to identify streets that have integration and connectivity. In addition, this study also uses the PTAL (Public Transport Accessibilty Levels) method to evaluate the level of accessibility of public transportation in an area. The results of the study show that there is a relationship between connectivity and integration of routes in the Cipete Raya area. There are several areas in the eastern part that have better public transportation accessibility compared to the western region. This shows the need for improvements in the provision of public transportation in the area in order to create better accessibility such as adding modes of transportation or increasing the frequency of Transjakarta buses.

Comparison and Assessment of Different Land Cover Datasets on the Cropland in Northeast China

The provision of precise and dependable information regarding the extent and distribution of cropland is imperative for the evaluation of food security, agricultural planning, and resource management. Cropland is an important component of land cover type and is offered in multiple existing global/regional land cover products. However, global-scale accuracy evaluation may not be representative of class-specific or local-area accuracy, such as in Northeast China, which is an important grain-producing region of China and has various types of cultivated land (e.g., wheat, rice) and diverse terrains. It poses a great challenge in generating precise cropland classification by automated mapping. Thus, it is indispensable to evaluate the accuracy and reliability of these various land cover datasets before using them. In this study, we collected thirteen sets of global or national-scale land cover datasets. Through the visual interpretation of high-resolution images, ground “truth” samples were collected to evaluate the data accuracy across Northeast China. The overall accuracy (OA) evaluation results in Phase-2020 show that CLCD has the highest value with 0.914, followed by GlobeLand30 (0.906), GLC_FCS30 (0.902), and Esri (0.896) for cropland classification in Northeast China. CGLS-LC100 has the lowest OA (0.710). For the commission and omission errors of six datasets in Phase-2020, CGLS-LC100 has an obvious overestimation (larger commission error), while the two national-scale datasets (CLCD and CLUDs) perform relatively better. In terms of spatial consistency, high spatial agreement among the nine Phase-2015 datasets or in the six Phase-2020 datasets could be discovered in traditional agricultural regions like the Sanjiang–Songnen–Liaohe Plain, and low agreement is found in the transition areas of mountains (hills) and plains with the mixed landscape of forest (grassland) and farmland. In the aspect of comparison pairwise data, CLCD is in good agreement with GLC_FCS30, GlobeLand30, and Esri, while CGLS-LC100 is in the poorest agreement with any other dataset. The comparison and evaluation results are expected to provide a reference on which aspects and to what extent these land cover products may be consistent and guide the cropland data product selection for Northeast China.

New constraints for the western Paleotethys paleogeography-paleotectonics derived from detrital signatures: Malaguide Carboniferous Culm Cycle (Betic Cordillera, S Spain)

Carboniferous sandstone within the Paleo-Mesomediterranean Domain (Malaguide Subdomain), in southern Spain, represents a key detrital mode within the sedimentary budget of convergent plate boundaries during the Variscan s.s. to Paleotethysian orogenic time span (≈420–300 Ma). This Carboniferous detritus corresponds with Culm lithostratigraphic depositional unit, and it covers an important gap of information (paleogeographic, paleotectonic, source areas) to the area located between the Iberian-French massifs and the African Paleo-Atlas, in the western Paleotethys. Sandstone composition is quartzolithic and records an important high-to-medium-low grade metamorphic content. The source area was a lithic and transitional recycled orogen with a signature of volcanic and ophiolitic detritus (≈330 Ma and/or older). These supplies seem to be derived from a mid-crustal deformed and thrusted pre-late Ordovician to Early Carboniferous terrane, involved in the plate convergence (the southern Europe Iberian-French massifs overriding the north African area) southeatwards of the Variscan s.s. orogenic system, rapidly exhumed and uplifted at mid-Late Carboniferoous time. Consequently, in the overriding hinterland (southern Europe: Iberian-French massifs), metamorphic basement should be already structured during middle Carboniferous when thrusting took place and deposition of Culm facies started in the Malaguide Complex, suggesting Proterozoic-Early Carboniferous (most probably, ≈420 to 330 Ma) metamorphic highlands. The presence of serpentinite-like detritus (≈330 Ma and/or older) seems to indicate a metamorphosed oceanic crust being dismantled at that time. Thus, sources from ophiolitic suture (most probably developed at ≈420–330 Ma) zones are tentatively proposed in other northern Gondwana of southwestern Europe. The occurrence of a synsedimentary volcanic activity (andesitic) should be related to a lost magmatic arc (most probably developed at ≈360–330 Ma), reinforcing the idea of a nearby subduction area. Therefore, the thick terrigenous Culm deposits (≈330–300 Ma) from the Malaguide Subdomain could be deposited in a complex foreland system basin connected northward with carbonate platforms and with a crystalline highland uplifted domain from the southern Europe Iberian-French massifs and southward with the African Paleo-Atlas Domain. The studied mid- to late Carboniferous sandstone petrofacies deeply contributes to paleogeographic reconstructions since block fragmentation and spreading, during the Paleotethysian and Alpine orogenies, rearranged the Paleozoic paleogeography now part of the Cenozoic Perimediterranean Chains. After the correlation with the Carboniferous from other western Paleotethys domains, new paleogeographic-paleotectonic constraints are proposed for the transitional area between the Iberian-French massifs and the African Paleo-Atlas Domain.

Impact of Transition Areas on Driving Workload and Driving Behavior in Work Zones: A Naturalistic Driving Study

Significant changes in road and traffic conditions in transition areas are key to traffic organization and guaranteeing safety in freeway work zones. Currently, most of the related studies on transition area use theoretical calculations, traffic and driving simulations, and the impact of different transition area conditions on drivers’ psychophysiological indicators and driving behavior are unclear. In this paper, the gap acceptance theory was used to establish a calculation method of the transition area length, and the transition area length was calculated under different closed lane widths, speed limits, and traffic volumes. Based on the results of our theoretical calculations, naturalistic driving experiments were conducted with 48 participants in 12 scenarios involving 3 lane closure forms and 4 transition area lengths, and the relationship of transition area with driving workload and vehicle speed was determined. A transition area that was too short or too long increased traffic safety risks. The overall experimental results were consistent with the theoretical calculation length, and the theoretical calculation model was reliable. Compared to unaffected straight-through vehicles, merging vehicles and vehicles affected by merging have lower speeds, higher driving workloads, and increased traffic safety risks. An increase in the number of lanes in the transition area will result in increased driving workloads and vehicle speeds. Based on the changes in vehicle deceleration points and driving workloads, the affected area of the transition area was measured. When the speed limit was 60 km/h, the upstream affected areas of the transition areas with four, three, and two lanes were 1000 m, 850 m, and 700 m, and the downstream affected areas were 450 m, 400 m, and 350 m. These research results can provide a reference for improving traffic organization and guaranteeing safety in freeway work zones.

Toward safer highway work zones: An empirical analysis of crash risks using improved safety potential field and machine learning techniques

Due to complex traffic conditions, transition areas in highway work zones are associated with a higher crash risk than other highway areas. Understanding risk-contributing features in transition areas is essential for ensuring traffic safety on highways. However, conventional surrogate safety measures (SSMs) are quite limited in identifying the crash risk in transition areas due to the complex traffic environment. To this end, this study proposes an improved safety potential field, named the Work-Zone Crash Risk Field (WCRF). The WCRF force can be used to measure the crash risk of individual vehicles that enter a work zone considering the influence of multiple features, upon which the overall crash risk of the road segment in a specific time window can be estimated. With the overall crash risk used as a label, the time-window-based traffic data are used to train and validate an eXtreme Gradient Boosting (XGBoost) classifier, and the Shapley Additive Explanations (SHAP) method is integrated with the XGBoost classifier to identify the key risk-contributing traffic features. To assess the proposed approach, a case study is conducted using real-time vehicle trajectory data collected in two work zones along a highway in China. The results demonstrate that the WCRF-based SSM outperforms conventional SSMs in identifying crash risks in work zone transition areas on highways. In addition, we perform lane-based analysis regarding the impact of setting up work zones on highway safety and investigate the heterogeneity in risk-contributing features across different work zones. Several interesting findings from the analysis are reported in this paper. Compared to existing SSMs, the WCRF-based SSM offers a more practical and comprehensive way to describe the crash risk in work zones. The approach using the developed WCRF technique offers improved capabilities in identifying key risk-contributing features, which is expected to facilitate the development of safety management strategies for work zones.

Seasonal variations in spatial distribution, mobilization kinetic and toxicity risk of arsenic in sediments of Lake Taihu, China

This study investigated seasonal variations in spatial distribution, mobilization kinetic and toxicity risk of arsenic (As) in sediments of three representative ecological lakes in Lake Taihu. Results suggested that the bioavailability and mobility of As in sediments depended on the lake ecological types and seasonal changes. At the algal-type zones and macrophyte-type zones, elevated As concentrations were observed in April and July, while these occurred at the transition areas in July and October. The diffusion flux of soluble As ranged from 0.03 to 3.03 ng/cm2/d, indicating sediments acted as a source of As. Reductive dissolution of As-bearing iron/manganese-oxides was the key driver of sediment As remobilization. However, labile S(-II) caused by the degradations of algae and macrophytes buffered sediment As release at the algal-type and macrophyte-type zones. Furthermore, the resupply ratio was less than 1 at three ecological lakes, indicating the resupply As capacity of sediment solid phase was partially sustained case. The risk quotient values were higher than 1 at the algal-type zones and transition areas in July, thereby, the adverse effects of As should not be ignored. This suggested that it is urgently need to be specifically monitored and managed for As contamination in sediments across multi-ecological lakes.

First Optimization of Novel, Potent, Selective PDE11A4 Inhibitors for Age-Related Cognitive Decline.

Phosphodiesterase 11A4 (PDE11A4) is a dual-acting cyclic nucleotide hydrolase expressed in neurons in the CA1, subiculum, amygdalostriatal transition area and amygdalohippocampal area of the extended hippocampal formation. PDE11A4 is the only PDE enzyme to emanate solely from hippocampal formation, a key brain region for the formation of long-term memory. PDE11A4 expression increases in the hippocampal formation of both humans and rodents as they age. Interestingly, PDE11A knockout mice do not show age-related deficits in associative memory and show no gross histopathology. This suggests that inhibition of PDE11A4 might serve as a therapeutic option for age-related cognitive decline. A novel, yeast-based high throughput screen previously identified moderately potent, selective PDE11A4 inhibitors, and this work describes initial efforts that improved potency more than 10-fold and improved some pharmaceutical properties of one of these scaffolds, leading to selective, cell-penetrant PDE11A4 inhibitors, one of which is 10-fold more potent compared to tadalafil in cell-based activity.

Impacts of climate change and habitat loss on the distribution of the endangered crested capuchin monkey (Sapajus robustus).

The crested capuchin monkey (Sapajus robustus) is endemic to the Atlantic Forest and its transition areas within Cerrado in Brazil. The species is currently threatened by habitat loss and has been classified as endangered by the IUCN Red List of Threatened Species since 2015. We used ecological niche models built with MaxEnt to predict the potential impact of climate change on the distribution of this species. The models were projected onto the reference climate, considering six climate scenarios (three Global Climate Models and two Representative Concentration Pathways) from IPCC for 2050 and 2070. We showed that while the amount of suitable area is expected to change little across the species' range in most evaluated climate scenarios, climatic conditions may significantly deteriorate by 2070 in the pessimistic scenario, especially in currently warmer and dryer areas to the west. As seen on other capuchin monkeys, the potential use of tools by crested capuchins may increase the chances of the species adaptation to novel harsher environmental conditions. The major negative impacts across the species range also include habitat loss and fragmentation so that the conservation of the species relies on the protection of the forest remnants in the center of its distribution, which can harbor populations of the species in current and future climate scenarios.

Automated Interlayer Wall Height Compensation for Wire Based Directed Energy Deposition Additive Manufacturing.

Part quality monitoring and control in wire-based directed energy deposition additive manufacturing (w-DEDAM) processes has been garnering continuous interest from both the academic and industrial sectors. However, maintaining a consistent layer height and ensuring that the wall height aligns closely with the design, as depicted in computer-aided design (CAD) models, pose significant challenges. These challenges arise due to the uncertainties associated with the manufacturing process and the working environment, particularly with extended processing times. To achieve these goals in an industrial scenario, the deposition geometry must be measured with precision and efficiency throughout the part-building process. Moreover, it is essential to comprehend the changes in the interlayer deposition height based on various process parameters. This paper first examines the behaviour of interlayer deposition height when process parameters change within different wall regions, with a particular focus on the transition areas. In addition, this paper explores the potential of geometry monitoring information in implementing interlayer wall height compensation during w-DEDAM part-building. The in-process layer height was monitored using a coherent range-resolved interferometry (RRI) sensor, and the accuracy and efficiency of this measurement were carefully studied. Leveraging this information and understanding of deposition geometry, the control points of the process parameters were identified. Subsequently, appropriate and varied process parameters were applied to each wall region to gradually compensate for wall height. The wall height discrepancies were generally compensated for in two to three layers.