Initial Process Research Articles

Classroom practices in primary schools’ mathematics teaching supported by the Interactive Mathematics Software for Rwanda

Over recent decades, the integration of technological resources in education increased growingly. However, studies about the assessment of information and communications technology integration in primary school mathematics activities remained few. This research intended to comparatively examine the aspects of classroom practices observed during the implementation of the Interactive Mathematics (IM) Software in primary schools in Rwanda. Designed as quasi-experimental, it involved the experimental groups from Primary-2, Primary-3, Primary-4, and Primary-5 and analyzed aspects of school statuses, the school years, and the educational cycles. Data collected using Likert-scale measurements from 63 classroom observations were analyzed using Microsoft Excel and a two-sample t-test analysis was conducted to determine if the significance of mean differences. The findings revealed no significant difference between lower and upper primary based on a p-value of 0.829368908 (p-value>.05) and between the 2019 and 2020 teaching periods (considering the same teacher) based on the p-value=0.324542 (p-value>.05). However, the findings revealed that private and public schools’ mean differences were significant based on the calculated p-value<em> </em>equal to 0.007144 (p-value<.01). The study made various recommendations towards using IM software to promote quality mathematics education in primary schools in Rwanda and pre-service teacher training to boost the initiation process of their technology-enhanced pedagogy knowledge to teach mathematics.

Progress and Complexities in Metal–Air Battery Technology

Metal–air batteries (MABs) offer exceptional energy density, making them attractive for vehicle electrification and storing intermittent renewable energy. However, several challenges persist, including sluggish oxygen reduction and oxygen evolution reactions, interfacial stability issues, and challenges related to current collectors. Herein, the reasons behind MAB's failures are analyzed, considering their thermodynamic aspects (Gibbs free energy, entropy), electrochemical factors (redox potentials, polarization, and ion concentrations), and kinetic properties (mobility of charges). Strategies for mitigating energy barriers of the electrodes are explored, encompassing insights into the initiation process of the oxygen reduction and determinants of oxygen evolution kinetics. The impact of humidity on the electrolyte is assessed, and effective methods for dendrite prevention are elucidated. Additionally, the utilization of 3D electrodes, oxygen‐selective membranes, solid‐state electrolytes, hybrid polymer electrodes, conductive electrocatalysts, and artificial solid‐electrolyte interfaces, and their effects on addressing the challenges faced by MABs are discussed. The study also emphasizes six critical commercialization aspects for the advancement of MABs. Lastly, the potential prospects and challenges in the field of MAB technology are discussed.

Job search strategies and early careers of clinical informatics fellowship alumni (2016-2022).

To report on clinical informatics (CI) fellows' job search and early careers. In the summer of 2022, we performed a voluntary and anonymous survey of 242 known clinical informatics fellowship alumni from 2016 to 2022. The survey included questions about their initial job search process; first job, salary, and informatics time after training; and early career progression over the first 1-6 years after fellowship. Nearly half (101, 41.7%) responded to the survey. Median informatics time was 50%; most were compensated similar/better than a purely clinical position. Most reported CI fellowship significantly impacted their career, were satisfied with their first and current job after training, and provided advice for current fellows and CI education leaders. Graduates in 2022 had a median job search of 5 months, beginning 3-15 months before graduation; most had a position created for them. Nearly all graduates from 2016-2021 (61, 93.8%) had at least one change in roles/benefits since finishing training, with a trend for increased informatics time and salary. There was a wide variety of roles, salary, and funding sources for CI positions. This highlights some of the unique challenges CI fellows face and the importance of networking. These results will help CI education leaders, fellows, alumni, and prospective fellowship applicants. Graduates felt that CI fellowship had a significant impact on their career, were pleased with their first jobs and early career trajectory. Continued follow-up of the experience of new graduates and alumni is needed to assess emerging patterns over time.

Neutrophil-Lymphocyte Ratio Value as a Predictor of Troponin Elevation in Patients with Non-ST Segment Elevation Acute Coronary Syndrome

Acute coronary syndrome (ACS) is a prominent contributor to mortality and morbidity on a global scale, consistently ranking within the top five primary causes. Inflammation is one of the many elements that have a role in the pathophysiology of the development and destabilization of plaque atherosclerosis in ACS. Troponin is a component of a biomarker that signals damage to the heart muscle in ACS patients; however, at the present time, not all medical facilities are able to perform troponin testing. An acute myocardial infarction begins with an initial inflammatory process that generates proinflammatory cytokines at the cellular level. This can be evaluated by the NLR through peripheral blood tests. The NLR as an indication of systemic inflammation has been demonstrated to be associated with poor clinical outcomes, an increased risk of complications, and mortality in ACS patients. In addition, several studies showed that the NLR has prognostic value in patients with ACS. The NLR is a mix of inflammatory markers, which can be a predictor of increased troponin in cases of non-ST segment elevation acute coronary syndrome (NSTEACS) in an emergency room.

Exploring the Relation Between Interstitial Lung Diseases and Chronic Periodontitis: A Systematic Review.

The objective of this systematic review is to determine the association between interstitial lung diseases and chronic periodontitis from various aspects such as microbial, biomarker, genetic, and environmental levels. A systematic review was carried out from 2000 to 2021 following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) recommendations including studies searched in PubMed-Medline, Google Scholar, and Cochrane databases. A total of more than 100 articles were obtained in the initial screening process. Out of these 42 studies fulfilled the inclusion criteria and were included in the study. According to the extracted data, there is mounting evidence suggesting the association between these two diseases. Our systematic review raises the prospect of a connection between chronic periodontitis and interstitial lung diseases, within the limitations of the studies we included.

Towards Automated Target Picking in Scalar Magnetic Unexploded Ordnance Surveys: An Unsupervised Machine Learning Approach for Defining Inversion Priors

With advancements in both the quality and collection speed of magnetic data captured by uncrewed aerial vehicle (UAV)-based systems, there is a growing need for robust and efficient systems to automatically interpret such data. Many existing conventional methods require manual inspection of the survey data to pick out candidate areas for further analysis. We automate this initial process by implementing unsupervised machine learning techniques to identify small, well-defined regions. When further analysis is conducted with magnetic inversion algorithms, then our approach also reduces the nonlinear computation and time costs by breaking one huge inversion problem into several smaller ones. We also demonstrate robustness to noise and sidestep the requirement for large quantities of labeled training data: two pitfalls of current automation approaches. We propose first to use hierarchical clustering on filtered magnetic gradient data and then to fit ellipses to the resulting clusters to identify subregions for further analysis. In synthetic data experiments and on real-world datasets, our model successfully captures all true targets while simultaneously proposing fewer computationally costly false positives. With this approach, we take an important step towards fully automating the detection of high-risk subregions, but we wish to emphasize the importance of prudent skepticism until it has been tested and proven on more diverse data.

Density Functional Theory Simulation of Iron-Montmorillonite as Carbon Dioxide Adsorber

Carbon dioxide (CO2) is a greenhouse gas that naturally keep the Earth^s surface temperature warm but currently the levels cause environmental problem such as climate change. Carbon capture and storage (CCS) technology is built to reduce CO2 gas emissions by binding carbon dioxide molecules and then storing them or utilising them as more useful products. In this study, simulations were carried out for the addition of iron (Fe) impurities as additional cation in montmorillonite to see the increase in the ability to bind carbon gas. Density Functional Theory calculations were carried out using additional corrections such as Van der Waals (vdW) and Hubbard-U. Here we got that Fe cation can help CO2 adsorbtion compare with other site without Fe atom by adding acid cite condition. But to adsorb CO2, the structure need initial process to swell the montmorillonite interlayer to certain optimum distance.

The defect feature extraction of ultrasonic phased array detection based on adaptive region growth.

An ultrasonic phased array defect extraction method based on adaptive region growth is proposed, aiming at problems such as difficulty in defect identification and extraction caused by noise interference and complex structure of the detected object during ultrasonic phased array detection. First, bilateral filtering and grayscale processing techniques are employed for the purpose of noise reduction and initial data processing. Following this, the maximum sound pressure within the designated focusing region serves as the seed point. An adaptive region iteration method is subsequently employed to execute automatic threshold capture and region growth. In addition, mathematical morphology is applied to extract the processed defect features. In the final stage, two sets of B-scan images depicting hole defects of varying sizes are utilized for experimental validation of the proposed algorithm's effectiveness and applicability. The defect features extracted through this algorithm are then compared and analyzed alongside the histogram threshold method, Otsu method, K-means clustering algorithm, and a modified iterative method. The results reveal that the margin of error between the measured results and the actual defect sizes is less than 13%, representing a significant enhancement in the precision of defect feature extraction. Consequently, this method establishes a dependable foundation of data for subsequent tasks, such as defect localization and quantitative and qualitative analysis.

The cerebellum directly modulates the substantia nigra dopaminergic activity.

Evidence of direct reciprocal connections between the cerebellum and basal ganglia has challenged the long-held notion that these structures function independently. While anatomical studies have suggested the presence of cerebellar projections to the substantia nigra pars compacta (SNc), the nature and function of these connections (Cb-SNc) is unknown. Here we show, in mice, that Cb-SNc projections form monosynaptic glutamatergic synapses with dopaminergic and non-dopaminergic neurons in the SNc. Optogenetic activation of Cb-SNc axons in the SNc is associated with increased SNc activity, elevated striatal dopamine levels and increased locomotion. During behavior, Cb-SNc projections are bilaterally activated before ambulation and unilateral lever manipulation. Cb-SNc projections show prominent activation for water reward and higher activation for sweet water, suggesting that the pathway also encodes reward value. Thus, the cerebellum directly, rapidly and effectively modulates basal ganglia dopamine levels and conveys information related to movement initiation, vigor and reward processing.

P088 Single-cell transcriptomic analysis identifies early immune disturbances in preclinical Crohn's disease

Abstract Background Despite the increasing incidence of Crohn’s disease (CD), its early immune disturbances have not been described yet. The preclinical period provides an opportunity to gain insight into the initial processes involved in the pathogenesis of the disease. The main aim of our study was to describe how the subclinical inflammatory process is modifying the individual’s immunologic environment while the patient is still on preclinical period. Methods We analysed scRNASeq data from peripheral blood mononuclear cells (PBMC) of patients with incidentally-diagnosed CD according to ECCO criteria during the colorectal cancer screening programme, after histologic confirmation. Their gene expression profile was compared to healthy individuals acquired from publicly available datasets. The analytical pipeline included merging of the datasets followed by batch correction concerning integration from different studies, quality control and filtering, and finally cell-type annotation and differential gene expression analysis. Results Two patients with CD (mean age 53,5 years) and 2 healthy controls were included. We observed distinct transcriptomic profile in preclinical patients compared to controls, with small intragroup differences. The cell-type annotation identified B cells (B), CD4+ and CD8+ T-cells (CD4T, CD8T), dendritic cells (DC), monocytes (Mono) and natural killer cells (NK). The analytical pipeline included 17,021 cells (B:3,274, CD4T:5,798, CD8T:3,476, DC:315, 2, Mono:928, NK:3,230) and 3000 quantified genes. Considering each cell type individually, we identified 49 differentially expressed genes (DEG) between CD patients and controls (B:39, CD4T:37, CD8T:41, DC:42, Mono:37, NK:37), from which 30 were DEGs in all cell types. Building on the list of 49 detected DEGs, we report three insights into the preclinical period of the disease. First, pathway analysis revealed significant enrichment of the pathway that is related to immunoregulatory interactions between lymphoid and non-lymphoid cells, and functional annotation analysis identified gene products that are related to immunological defense. Second, we identified significant transcriptomic alterations in genes that have previously been related to the symptomatic phase of IBD, or reported as potential biomarkers. Third, after performing principal component analysis we observed greater separation between the patients groups in the CD8T cells compared to the other cell-types. Conclusion This study reveals the initial transcriptomic profiles and the main pathways that precede the onset of symptomatic inflammatory bowel disease. Our findings may help in identifying potential targets for early disease intervention.

Searching for memories: narratives about the initiation process of former athletes of the Brazilian futsal national team

Through the Development Model of Sport Participation framework and methodological perspective of oral history, this manuscript aims to narrate some fragments of the history of the sports initiation process of former elite athletes of the Brazilian Futsal Team. To this end, two interviews were conducted with athletes in the Brazilian Futsal Team during the 1980s and 1990s. From the oral history of two former futsal players, we identified evidence about the contribution of deliberate play in their initial stage of sport involvement. First, they highlighted the importance of the street and the family in their first contact with games played with feet, particularly futsal. Afterward, they emphasized the school, promoted diversified sports practices, and mentioned the role of the teacher in encouraging futsal practice in the scholar team. Finally, they evidenced the importance of social clubs and soccer practice during the transition to specialization years in futsal. It certainly contributed to their long-life athlete career. Key Words: Athlete development; School; Club; Family; Sport career

An end-to-end workflow for nondestructive 3D pathology.

Recent advances in 3D pathology offer the ability to image orders of magnitude more tissue than conventional pathology methods while also providing a volumetric context that is not achievable with 2D tissue sections, and all without requiring destructive tissue sectioning. Generating high-quality 3D pathology datasets on a consistent basis, however, is not trivial and requires careful attention to a series of details during tissue preparation, imaging and initial data processing, as well as iterative optimization of the entire process. Here, we provide an end-to-end procedure covering all aspects of a 3D pathology workflow (using light-sheet microscopy as an illustrative imaging platform) with sufficient detail to perform well-controlled preclinical and clinical studies. Although 3D pathology is compatible with diverse staining protocols and computationally generated color palettes for visual analysis, this protocol focuses on the use of a fluorescent analog of hematoxylin and eosin, which remains the most common stain used for gold-standard pathological reports. We present our guidelines for a broad range of end users (e.g., biologists, clinical researchers and engineers) in a simple format. The end-to-end workflow requires 3-6 d to complete, bearing in mind that data analysis may take longer.

Sound suppresses earliest visual cortical processing after sight recovery in congenitally blind humans

Neuroscientific research has consistently shown more extensive non-visual activity in the visual cortex of congenitally blind humans compared to sighted controls; a phenomenon known as crossmodal plasticity. Whether or not crossmodal activation of the visual cortex retracts if sight can be restored is still unknown. The present study, involving a rare group of sight-recovery individuals who were born pattern vision blind, employed visual event-related potentials to investigate persisting crossmodal modulation of the initial visual cortical processing stages. Here we report that the earliest, stimulus-driven retinotopic visual cortical activity (<100 ms) was suppressed in a spatially specific manner in sight-recovery individuals when concomitant sounds accompanied visual stimulation. In contrast, sounds did not modulate the earliest visual cortical response in two groups of typically sighted controls, nor in a third control group of sight-recovery individuals who had suffered a transient phase of later (rather than congenital) visual impairment. These results provide strong evidence for persisting crossmodal activity in the visual cortex after sight recovery following a period of congenital visual deprivation. Based on the time course of this modulation, we speculate on a role of exuberant crossmodal thalamic input which may arise during a sensitive phase of brain development.

Clinical reasoning during dysphagia assessment and management in acute care: A longitudinal qualitative study.

Competent clinical reasoning forms the foundation for effective and efficient clinical swallowing examination (CSE) and consequent dysphagia management decisions. While the nature of initial CSEs has been evaluated, it remains unclear how new information gathered by speech-language therapists (SLTs) throughout a patient's acute-care journey is integrated into their initial clinical reasoning and management processes and used to review and revise initial management recommendations. To understand how SLTs' clinical reasoning and decision-making regarding dysphagia assessment and management evolve as patients transition through acute hospital care from referral to discharge. A longitudinal, qualitative approach was employed to gather information from two SLTs who managed six patients at a metropolitan acute-care hospital. A retrospective 'think-aloud' protocol was utilized to prompt SLTs regarding their clinical reasoning and decision-making processes during initial and subsequent CSEs and patient interactions. Three types of concept maps were created based on these interviews: a descriptive concept map, a reasoning map and a hypothesis map. All concept maps were evaluated regarding their overall structure, facts gathered, types of reasoning engaged in (inductive versus deductive), types of hypotheses generated, and the diagnosis and management recommendations made following initial CSE and during subsequent dysphagia management. Initial CSEs involved a rich process of fact-gathering, that was predominantly led by inductive reasoning (hypothesis generation) and some application of deductive reasoning (hypothesis testing), with the primary aims of determining the presence of dysphagia and identifying the safest diet and fluid recommendations. During follow-up assessments, SLTs engaged in increasingly more deductive testing of initial hypotheses, including fact-gathering aimed at determining the tolerance of current diet and fluid recommendations or the suitability for diet and/or fluid upgrade and less inductive reasoning. Consistent with this aim, SLTs' hypotheses were focused primarily on airway protection and medical status during the follow-up phase. Overall, both initial and follow-up swallowing assessments were targeted primarily at identifying suitable management recommendations, and less so on identifying and formulating diagnoses. None of the patients presented with adverse respiratory and/or swallowing outcomes during admission and following discharge from speech pathology. Swallowing assessment and management across the acute-care journey was observed as a high-quality, patient-centred process characterized by iterative cycles of inductive and deductive reasoning. This approach appears to maximize efficiency without compromising the quality of care. The outcomes of this research encourage further investigation and translation to tertiary and post-professional education contexts as a clear understanding of the processes involved in reaching diagnoses and management recommendations can inform career-long refinement of clinical skills. What is already known on the subject SLTs' clinical reasoning processes during initial CSE employ iterative cycles of inductive and deductive reasoning, reflecting a patient-centred assessment process. To date it is unknown how SLTs engage in clinical reasoning during follow-up assessments of swallowing function, how they assess the appropriateness of initial management recommendations and how this relates to patient outcomes. What this paper adds to the existing knowledge Our longitudinal evaluation of clinical reasoning and decision-making patterns related to swallowing management in acute care demonstrated that SLTs tailored their processes to each patient's presentation. There was an emphasis on monitoring the suitability of the initial management recommendations and the potential for upgrade of diet or compensatory swallowing strategies. The iterative cycles of inductive and deductive reasoning reflect efficient decision-making processes that maintain high-quality clinical care within the acute environment. What are the potential or actual clinical implications of this work? Employing efficient and high-quality clinical reasoning is a hallmark of good dysphagia practice in maximizing positive patient outcomes. Developing approaches to understanding and making explicit clinical reasoning processes of experienced clinicians may assist SLTs of all developmental stages to provide high standards of care.

APN nurses' core competencies for general clinical health assessment in primary health care. A scoping review.

The field of Advanced Practice Nursing (APN) has developed over the past six decades. However, the definition of roles and responsibilities of APN nurses seem to be contested due to both a lack of a clear definition of the concept and to institutional and cultural barriers that restrict the nurses' opportunities to practise to the full extent of their competencies. The objective of this scoping review was to identify, examine and conceptually map the available literature on APN nurses' core competencies for general health assessment in primary health care. We performed a scoping review, following the methodological guidance for reporting as it is described by the Joanna Briggs Institute (JBI). Furthermore, the PRISMA-ScR statement and checklist for reporting scoping reviews were followed. Guiding the initial process for the search, we used the Population, Concept and Context mnemonic (PCC) to clarify the focus and context of the review. We found three areas of core competencies on which APN nurse draw in performing general health assessments in primary health care: (1) 'Collaborative, leadership and management skills' (2) 'Person-centred nursing care skills' and (3) 'Academic and educational skills'. Furthermore, we found that the three areas are interrelated, because it is crucial that APN nurses draw on collaborative competencies related to leadership and management to meet the service users' needs and deliver high-quality and person-centred care. There is a need for a more specific investigation into how APN nurses' core competencies play a role during general health assessments of patients in primary care. We suggest an evaluation of what works for whom in what circumstances looking into the interrelation between competencies, skills and knowledge when an APN nurse performs a general health assessment in a primary healthcare setting.

Determination of Significant Three-Dimensional Hemodynamic Features for Postembolization Recanalization in Cerebral Aneurysms Through Explainable Artificial Intelligence

BackgroundRecanalization poses challenge in coil embolization for cerebral aneurysms. Establishing predictive models for post-embolization recanalization is important for clinical decision-making. However, conventional statistical and machine learning (ML) models may overlook critical parameters during the initial selection process. MethodsIn this study, we automated the identification of significant hemodynamic parameters using a PointNet-based deep neural network (DNN), leveraging their inherent three-dimensional (3D) features. Further feature analysis was conducted utilizing saliency mapping, an explainable artificial intelligence (XAI) technique. The study encompassed the analysis of velocity, pressure, and wall shear stress (WSS) in both pre- and post-coiling models derived from computational fluid dynamic (CFD) simulations for 58 aneurysms. ResultsVelocity was identified as the most pivotal parameter, supported by the lowest P-value from statistical analysis and the highest area under the receiver-operating characteristic curves (AUROC)/precision-recall curves (AUPRC) values from DNN model. Moreover, visual XAI analysis revealed robust injection flow zones with notable impingement points in pre-coiling models, as well as pronounced interplay between flow dynamics and the coiling plane were important 3D features in identifying the recanalized aneurysms. ConclusionsThe combination of DNN and XAI was found to be an accurate and explainable approach not only at predicting post-embolization recanalization but also at discovering unknown features in the future.

Carbon-Atom Exchange between [MC2]+ (M = Os and Ir) and Methane: on the Thermodynamic and Dynamic Aspects.

Gas-phase reactions of [OsC2]+ and [IrC2]+ with methane at ambient temperature have been studied using quadrupole-ion trap mass spectrometry combined with quantum chemical calculations. Both [OsC2]+ and [IrC2]+ undergo carbon-atom exchange reactions with methane. The associated mechanisms for the two systems are found to be similar. The differences in the rates of carbon isotope exchange reactions of methane with [MC2]+ (M = Os and Ir) are explained by several factors like the energy barrier for the initial H3C-H bond breaking processes, the molecular dynamics, orbital interactions, and the H-binding energies of the pivotal steps. Besides, the number of participating valence orbitals might be one of the keys to regulate the rate in the key step. The present findings may provide useful ideas and inspiration for designing similar processes.

Testing the presence of cereal-type pollen grains in coastal pre-Elm Decline peat deposits: Fine-resolution palynology at Roudsea Wood, Cumbria, UK

By the time of the Mid-Holocene Ulmus pollen decline (UD) ca. 5100 14C bp (ca. 5900 cal. BP), the Neolithic was becoming well established in Britain and Ireland. The importance of cereal cultivation as part of the initial neolithization process in the British Isles is uncertain, as archaeological sites of the first Neolithic remain elusive. Palaeoecologists have recorded cereal-type pollen grains in peat deposits that pre-date the UD significantly, but as some wild grasses can produce pollen that closely resembles cereal pollen grains, these early pollen records are not trusted as evidence of cereal cultivation. Some of these wild grass taxa grow in coastal wetland environments, making cereal-type pollen from such locations particularly open to question. This study uses fine-resolution palynology through a sequence of coastal hydroseral deposits that contain no evidence of human activity, to look for the presence of wild grass pollen of cereal size and morphology. Our results show that while such grains are not recorded at 1 cm resolution, at contiguous 2 mm resolution sampling sporadic occurrences of large grass pollen of possible cereal-type, resembling Hordeum, were detected. Morphology suggests that these cereal-type grains are of wild grass origin, almost certainly Glyceria, but their presence suggests that high-resolution analyses of coastal zone sediments will often discover cereal-type grains. Great care must be taken in identifying cereal-type pollen in coastal palaeo-wetland sediments, and rigorous identification protocols should be applied. Where grains could still be of cultivated cereal-type, the presence of other disturbance indicators is an important factor in inferring their origin.

Successional development of the phototrophic community in biological soil crusts, along with soil formation on Holocene deposits at the Baltic Sea coast

Harsh environmental conditions form habitats colonized by specialized primary microbial colonizers, e.g., biological soil crusts (biocrusts). These cryptogamic communities are well studied in drylands but much less in temperate coastal dunes, where they play a crucial role in ecological functions. Following two dune chronosequences, this study highlights the successional development of the biocrust’s community composition on the Baltic Sea coast. A vegetation survey, followed by morphological species determination, was conducted. Sediment/soil cores of the different dune types were analyzed to uncover the potential impacts of the biocrust community on initial soil formation processes, with special emphasis on biogeochemical phosphorous (P) transformations. Biocrust succession was characterized by a dune type-specific community composition, shifting from thinner algae-dominated biocrusts in dynamic dunes to more stable moss-dominated biocrusts in mature dunes. The change in the biocrust community structure was accompanied by an increase in Chl a, water, and organic matter content. In total, 25 algal and cyanobacterial species, 16 mosses, and 26 lichens across all sampling sites were determined. The pedological characterization of these cores elucidated initial processes of soil genesis, such as decalcification, acidification, and the accumulation of organic matter with dune and biocrust development. Furthermore, the chemistry of iron (Fe)-containing compounds such as the Fedithionite/Fetotal ratios confirmed mineral weathering and the beginning of soil profile development. The biocrusts accumulated P over time, while the P content in the underlying sediment did not change. That implies that biocrusts take up P from the geological parent material in the dunes, thereby accumulating available P in the ecosystem, which gets transferred into subsoil horizons through leaching or redeposition. The relative proportion of the bioavailable P pool (56% to 74% of Pt) increased with dune succession. That happened at the expense of more stable bound P, which was transformed into labile P. Thus, the level of plant available P along the dune chronosequences increased due to the microbial activity of the biocrust organisms. It can be concluded that biocrusts of temperate coastal dunes play a crucial role in maintaining their habitat by accumulating nutrients and organic matter, supporting soil development and subsequent vegetation.

Failure behaviors of EB-PVD thermal barrier coatings under isothermal oxidation and thermal cycling conditions

The thermal growth oxide (TGO) layer formed by oxidation of the bond coat (BC) layer is an important factor affecting the durability of thermal barrier coatings (TBCs). In this study, a series of isothermal oxidation and thermal cycling experiments were performed on samples containing TBCs at different temperatures. The initiation, propagation and connection process of cracks in the cross-section of the samples were studied, and the oxidation failure mechanism of the samples was analyzed. The results demonstrate that the diffusion of the Al element in NiCoCrAlYHf coating to the top coat (TC) layer promotes the formation and rapid thickening of TGO at TC/BC interface. With the consumption of Al, two sublayers of mixed oxide layer and Al2O3 layer are gradually formed in the TGO layer. The TC/TGO interface is the main initiation location of interface crack. In addition, the types and initiation locations of cracks caused by isothermal oxidation are different from those caused by thermal cycling. Under isothermal oxidation, the TC layer near the TC/TGO interface and the TC/TGO interface are prone to induce horizontal cracks, which finally lead to the delamination and spalling of TBCs. Under the thermal cycling, vertical cracks occur in the TC layer, extend towards the TC/TGO interface, and merge with the interface cracks, eventually resulting in the delamination failure of the TBCs.