Deposition Patterns Research Articles

Schaumann bodies deposited along myenteric plexus of the muscularis propria is a unique histopathological feature of Crohn's disease.

Schaumann bodies were first identified in sarcoidosis by Dr Schaumann in 1941. They were also detected in 10% of Crohn's disease (CD) cases in a study involving patients with surgically resected CD. However, the characteristics and significance of Schaumann bodies in CD have yet to be fully elucidated. This study aimed to determine the pathological features and diagnostic significance of Schaumann bodies in various bowel diseases. Overall, 278 bowel specimens were collected from patients with CD, intestinal tuberculosis, ulcerative colitis, intestinal schistosomiasis, diverticulosis and idiopathic mesenteric vasculopathy. The frequency, pathology and clinical features of patients with Schaumann bodies were studied. Schaumann bodies were present exclusively in CD (27.0%, 38 of 141) and were not detected in other intestinal diseases within the series. In CD, Schaumann bodies were deposited along the myenteric plexus of the muscularis propria (84.2%, 32 of 38). These bodies were small (diameter: 60.3±32.7 µm) and exhibited a low density in the intestinal wall (1.1±0.4 per low-power field). The majority were located within the cytoplasm of multinucleated giant cells (84.2%, 32 of 38) and were not found within or adjacent to granulomas. Notably, the number of female patients with CD and Schaumann bodies was higher than that of males. Schaumann bodies are common in resected CD specimens, and their characteristic deposition pattern may serve as a diagnostic indication for CD.

Improved Olfactory Deposition of Theophylline Using a Nanotech Soft Mist Nozzle Chip.

Currently, nasal administration of active pharmaceutical ingredients is most commonly performed using swirl-nozzle-based pump devices or pressurized syringes. However, they lead to limited deposition in the more active regions of the nasal cavity, especially the olfactory region, which is crucial for nose-to-brain drug delivery. This research proposes to improve deposition in the olfactory region by replacing the swirl nozzle with a nanoengineered nozzle chip containing micrometer-sized holes, which generates smaller droplets of 10-50 μm travelling at a lower plume velocity. Two nanotech nozzle chips with different hole sizes were tested at different inhalation flow rates to examine the deposition patterns of theophylline, a hyposmia treatment formulation, using a nasal cavity model. A user study was also conducted and showed that the patient instructions influenced the inhalation flow rate characteristics. Targeted flow rates of between 0 and 25 L/min were used for the in vitro deposition study, yielding 21.5-31.5% olfactory coverage. In contrast, the traditional swirl nozzle provided only 10.8% coverage at a similar flow rate. This work highlights the potential of the nanotech soft mist nozzle for improved intranasal drug delivery, particularly to the olfactory region.

Joint Experimental and Theoretical Study on Deposition Morphologies in Polymer Sessile Droplets.

Although past experimental and theoretical research has made substantial progress in understanding evaporation behaviors in various suspensions, the fundamental mechanism for polymer sessile droplets is still lacking. One critical effect is the molecular weight on the evaporation behaviors. Here, systematic experiments are carried out to investigate the evaporation behavior of polymer droplets under the effects of polymer concentration, evaporation rate, and especially molecular weight. We obtain polymer films with various morphologies with molecular weights ranging from 2 orders of magnitude to 4 orders of magnitude and polymer concentration across 4 orders of magnitude. We further develop a theoretical model based on the Onsager principle to explain the evaporation mechanism from a dynamic perspective. Analysis indicates that increasing molecular weight or polymer concentration enhances the contact angle hysteresis and slows down the evaporation, resulting in the transition from multiring to coffee ring and eventually to uniform films. The findings offer a guideline for achieving the desired deposition patterns via droplet processing techniques.

Evolution from shallow‐water deltas to fluvial fans in lacustrine basins: A case study from the Middle Jurassic Shaximiao Formation in the central Sichuan Basin, China

AbstractDistinguishing between shallow‐water delta and fluvial fan deposits in the subsurface of lacustrine basins is challenging due to their similar depositional characteristics and distribution patterns. This study focuses on the Middle Jurassic Shaximiao Formation in the central Sichuan Basin using core observations, seismic analyses, petrology analyses, zircon analyses, palaeoclimate indicators and palaeocurrent analyses to address this issue. Fifteen sedimentary lithofacies and eight lithofacies associations were established, corresponding to channelized fluvial deposits, non‐channelized fluvial deposits and shallow‐water delta deposits. Shallow‐water deltas are dominated by channels and mouth‐bar complexes with grey, red and green interbedded mudstone. Shingled seismic reflection, green mud clasts, small burrows and wave ripples are common with occasional palaeosols. Fluvial fans are dominated by channels and crevasse‐splays with pink colour and accompanied by red coloured floodplain deposits. Bright spot seismic reflection, red mud clasts, big burrows, current ripples and palaeosols are common. The increased uplift of the Dabashan Mountains controls the palaeocurrent direction, promoting the evolution from a shallow‐water delta in relatively humid environments to a fluvial fan in relatively arid environments. The channel widths in shallow‐water deltas are wider than those in fluvial fans, whereas the opposite applies for the channel amalgamation rate. Highly frequent channel‐width variations are controlled by short‐cycle climate fluctuation, corresponding to chemical index of alteration value fluctuations in different sandstone groups. The channel width in the relatively humid environments is wider than that in arid environments for both shallow‐water deltas and fluvial fans. It is likely that the sedimentary evolution from shallow‐water deltas to fluvial fans is relatively common in lacustrine basins in relatively arid environments with wide and gentle slope landforms.

Investigating the effects of printing temperatures and deposition on the compressive properties and density of 3D printed polyetheretherketone

Polyetheretherketone (PEEK) is a biocompatible high-performance thermoplastic that can be processed through material extrusion (ME) additive manufacturing (AM) for load-bearing implant applications. In this work, density measurements and compression testing were used to investigate the relation between printing temperatures and deposition patterns of PEEK 3D printed samples. Different deposition patterns were tested with different nozzle and zone heater temperatures to observe how the heat input from the printing process influenced the deposition stability with different nozzle paths. Compression test results showed that samples with concentric-based deposition patterns resulted in higher compressive yield strength and modulus than the rectilinear samples. These results were correlated with the samples’ void contents estimated from density measurements. Both the highest 0.2% offset yield strength of 100.3 MPa and the highest modulus of 3.58 GPa were obtained with an interlayer offset deposition which resulted in reductions in estimated void contents between 48 and 72% in relation to concentric deposition. Different printing temperatures and deposition sequences were tested, where higher printing temperatures resulted in lower yield strength and stiffness. Alternating deposition between the outer and inner lines of the concentric pattern resulted in a reduction of about 43% in void contents and increased elastic modulus and yield strength from 3.12 to 3.40 GPa and 94.4 to 95.2 MPa respectively. The results from this work suggest that the relation between printing temperatures and deposition strategy for different print geometries plays a significant role in the ME-AM of PEEK for high-performance applications.

Thiamethoxam dynamics in pepper plants: Deciphering deposition and dissipation pattern across diverse planting modes and regions

To reduce the application dosage of thiamethoxam (TMX), we investigated the deposition and dissipation patterns in a pepper-planted ecosystem under different planting modes across four regions in China, namely Hainan (HN), Zhejiang (ZJ), Anhui (AH) and Hebei (HB). This study focused on the deposition and dissipation of TMX at concentrations of 63.00, 47.25, 31.50, 23.63 and 15.75 g a.i.hm-2. As the application dose increased, the deposition amount of TMX initially increased in the plants and cultivated soil, showing obvious geographic differences in four cultivation areas. Surprisingly, the initial amount of TMX deposited the pepper-cultivated greenhouse of ZJ and AH was 1.1–2.1-fold and 1.0–3.6-fold higher than that in the open field system at the same application dose, respectively. In pepper leaves, stems, fruits and soil, the dissipation exhibited rapid growth and then slowed. However, the residual concentration showed an increasing trend, followed by a subsequent decrease in the pepper roots. In different planting regions, the dissipation rate of TMX followed the order HN > ZJ > AH > HB in pepper plants and cultivated soil. In comparison to the open field, the total TMX retention rate in greenhouse was higher, indicating overall greater persistence in the greenhouse conditions. These findings reveal the deposition and dissipation characteristics of TMX within the pepper-field ecosystem, offering a significant contribution to the risk assessment of pesticides.

Age-Related Changes in Hepatic Lipid Metabolism and Abdominal Adipose Deposition in Yellow-Feathered Broilers Aged from 1 to 56 Days.

The objective of this study was to evaluate the age-related changes in hepatic lipid metabolism, adipocyte hyperplasia, hypertrophy, and lipid metabolism in the abdominal adipose tissue of yellow-feathered broilers. Blood, liver, and abdominal adipose samples were collected on days 1, 7, 14, 21, 28, 35, 42, 49, and 56. Body, liver, and abdominal weight increased (p < 0.05) with age-related changes. The triacylglycerol content peaked on day 14, and total cholesterol content peaked on day 56. The adipocyte diameter and area peaked on day 56, and total DNA content peaked on day 7. The age-related changes in hepatic lipogenesis-related gene (ChREBP, SREBP-1c, ACC, FAS, SCD1) expression mainly occurred during days 1 to 21, hepatic lipolysis-related gene (CPT1, LPL, ApoB) expression mainly occurred during days 1 to 14, and abdominal adipose-deposition-related gene (PPARα, CPT1, LPL, PPARγ, C/EBPβ) expression occurred during days 1 to 14. These results demonstrated a dynamic pattern of hepatic lipid metabolism and abdominal adipose deposition in yellow-feathered broilers, which provides practical strategies to regulate hepatic lipid metabolism and reduce abdominal adipose deposition in yellow-feathered broilers.

Walkaway vertical seismic profiling first-arrival traveltime tomography with velocity structure constraints

Abstract Walkaway vertical seismic profiling (WVSP) is known for its high level of credibility in obtaining the relationship between first-arrival traveltime and detector depth through first-arrival picking. This relationship can be utilized for seismic velocity model inversion to improve velocity model accuracy and rationality. Here, we present a WVSP first-arrival velocity model with velocity structure constraints, by utilizing layer and fault data interpreted by ground seismic structure technique. We constructed a geological structure and layer sequence models based on sedimentary patterns to obtain complex velocity structures. Furthermore, we introduced a smooth regularization term based on the velocity structure into the inversion model to enhance its consistency with geological laws and compensate for the reduced inversion accuracy owing to the regularization term based on flat structures. This approach addressed the limitations of the regularization term based on flat structures, resulting in more accurate and reliable inversion results. Through simulation analysis, the proposed method realized the WVSP first-arrival velocity inversion, with results being closer to those of the real velocity model.

Reconciling complex stratigraphic frameworks reveals temporally and geographically variable depositional patterns of the Campanian Ignimbrite

Abstract The 39.8-ka Campanian Ignimbrite was emplaced during a large caldera-forming eruption of Campi Flegrei near Naples, Italy. The ignimbrite is found up to 80 km from the caldera, and co-ignimbrite ash-fall deposits occur 3200 km away. The proximal and distal stratigraphy of the Campanian Ignimbrite has not been definitively correlated due to the dissimilar appearance of the proximal and distal deposits, a lack of medial exposures, and the inconsistency and heterogeneity of the proximal stratigraphy. Here, we document the major-element glass-shard chemistry, matrix componentry, and lithic componentry of the proximal and distal stratigraphic sequences of the ignimbrite to attempt to correlate the units. The results of these disparate observations taken together suggest that the established stratigraphic units cannot be directly and uniquely correlated between the proximal and distal regions and that neither the proximal nor distal stratigraphy provides a record of the entire eruptive sequence. However, the characteristics studied can be used to demarcate eruptive phases that are connected to some of the defined units in the proximal and distal stratigraphy.

Numerical Modelling and Sensitivity Analysis of the Pitztal Valley Debris Flow Event

Debris flows characterized by their rapid velocity and composition of water, mud, soil, and boulders, have the potential to inflict significant harm and present hazards to human life, infrastructure, and the natural surroundings. Numerical simulations provide a cost-effective approach for investigating different scenarios, hence boosting comprehension of flow dynamics and interactions. However, accurate modelling of these flows typically face difficult challenges arising from inherent modeling constraints and insufficient historical event data. The primary objective of the present study is to conduct numerical modeling and sensitivity analysis of the debris flow event that occurred in the Pitztal Valley, Austria in August of 2009, based on a multi-phase model for debris flows. The validation of the simulation results involves the comparison with the observed deposition patterns in the field. Various validation factors are employed to evaluate the accuracy of the simulated deposit and demonstrate a satisfactory level of precision in predicting deposition patterns. A sensitivity analysis is also conducted to examine the influence of in situ conditions on the effects of debris flow. The results demonstrate that numerical modelling can play an important role in engineering hazard assessment by analyzing the existing model’s effectiveness in simulating both historical and projected debris flow events.

Urine Analysis in Ayurveda and Modern Medicine: Exploring Convergence and Divergence

Urine examination has played a significant role in medical diagnostics across diverse civilizations throughout history. Ayurveda, a traditional healing system originating in the Indian subcontinent, placed importance on urine analysis as a diagnostic tool. In contrast, modern medical science employs sophisticated laboratory techniques and imaging technologies for urine examination. This manuscript delves into the historical context, techniques, and tools used in Ayurveda for urine examination, comparing them with contemporary scientific approaches. Ayurveda's holistic understanding, rooted in the concept of Tridosha utilized urine examination to identify imbalances and formulate personalized treatments. Ayurvedic physicians observed attributes like color, odor, and sedimentation patterns, aligning them with Doshic qualities. Modern urinalysis encompasses visual, chemical, and microscopic analyses, yielding critical clinical information. Elevated glucose, protein, ketones, presence of blood cells, and crystals provide insights into diabetes, kidney dysfunction, infections, and metabolic disorders. Advanced imaging techniques contribute to urinary tract evaluation. By juxtaposing Ayurvedic and modern approaches, potential correlations and synergies emerge, bridging ancient wisdom with contemporary evidence-based medicine. Integrating personalized Ayurvedic principles with objective modern methodologies could lead to enhanced diagnostic accuracy and patient care. Challenges in integration and the importance of holistic patient-centered care are acknowledged. The exploration of urine examination unites tradition and innovation, fostering interdisciplinary collaboration for a holistic approach to healthcare.

Pollen and non-pollen palynomorph depositional patterns in Kaziranga National Park, India: Implications for palaeoecology and palaeoherbivory analysis

The main aim of this study is to produce a modern analog for pollen and non-pollen palynomorphs (NPPs) preserved in soil in relation to the different vegetation types and herbivore impact in the Kaziranga National Park (KNP). The pollen data obtained reflects both the extant vegetation types in each habitat as well as landuse, but some site-by-site variation was observed with respect to the coprophilous fungal spores present in the palynoassemblage. Canonical correspondence analysis (CCA) analysis of pollen data reveals the presence of five significantly different vegetation types, while the non-pollen palynomorphs are relatively similar in relation to the different vegetation types. The long-term association of the wildlife and their impact on different vegetation types is one of the main reasons for the variation seen in the depositional pattern in the assemblage. The openland area is one of the most important areas for wildlife in the KNP as indicated by the presence of marker pollen and coprophilous fungal spores in the palynoassemblages. Coprophilous fungal spores were most abundant in this vegetation type reflecting the higher density of herbivores. The representation of pollen and coprophilous fungal spores from the swamp samples reflected the overall composition of all vegetation types existing in the KNP. This data can be utilized as a baseline for the interpretation of paleoecological and paleoherbivory studies in other parts of the Indian subcontinent as well as its potential application at a global level.

Informing directed energy deposition strategies through understanding the evolution of residual stress

Residual stress is a critical concern in directed energy deposition (DED) as it impacts the functional performance of components, in terms of load-bearing capacity and corrosion behavior. In this paper, an analytical model is developed to characterize the temperature distribution, residual stress profiles, and geometric distortions in DED-built components, which enables efficient planning of the DED strategies. The model combines a finite difference method to predict the temperature history, modified Green's functions to quantify thermal stress, and a radial return method to update plastic stress, which features the deposition of materials with heat source movement. The predictions are validated against the temperature, residual stress, and distortion profiles reported in the literature. In the fabrication of multiple-layer thin-wall structures, the model demonstrates a maximum prediction error of 18.2% for the peak temperature at the middle of the deposit-substrate interface and 17.7% for the vertical distortion of the deposit-substrate system. Simulation results from the model provide insights into understanding stress evolution in the deposition and offer guidance in the selection of linear energy density parameters (heat source power and traverse speed) and process planning parameters (idle time and deposition patterns) when designing DED strategies for thin-wall structures. This approach can be implemented in an efficient workflow to optimize the DED technologies for specified residual stress profiles within a component geometry regardless of heat source or material type.

Understanding the linkages between land-use transitions and soil erosion/sediment deposition: A case study of the transboundary Sio-Malaba-Malakisi watershed in Kenya and Uganda

Soil erosion consequent of unsustainable land-use practices represents one of the world's most pressing environmental problems affecting many watersheds. An assessment of sediment sources and delivery paths is essential for the development of site-specific soil management strategies for curbing environmental degradation. The present study employed a physically-based lumped approach to estimate soil erosion and sediment deposition patterns across the transboundary Sio-Malaba-Malakisi (SMM) watershed. The Unit Stream Power-based Erosion Deposition (USPED) model was adopted for the study, and integrated with physically-based parameters derived in a Geographical Information System (GIS). A land-use map for 2017 was used for simulating the reference soil erosion and deposition status of the basin. Furthermore, the impacts of two land-use scenarios representing options for cropland expansion (Scenario-I), and land reclamation (Scenario-II), were evaluated for the period 2047, corresponding to a thirty-year period used in assessing catchment management planning for SMM. The annual soil erosion ranged between 0 and 460 t. ha−1yr−1, with a mean erosion rate of 160 t.ha−1yr−1 for the baseline condition. Deposition zones were mainly concentrated along stream banks and floodplain in low-lying sub-catchments. The mean soil erosion rate increased by 61 % and 16 % for scenarios I and II respectively. Overall, the modelled erosion/deposition values were correlated with available sediment data for the basin, realizing a coefficient determination (R2) value of 0.74. These results could serve as a benchmark against which future trends in land-use changes can be compared in the region and hence support the development of regional soil erosion conservation strategies.

Self-cleaning effect and secondary swirling clean gas for suppressing particle deposition on vortex finder of gas cyclones

In order to suppressing the particle deposition on vortex finder, a series of gas cyclones with the secondary swirling clean gas were developed inspired by the gas purge effect. Effects of the width and extension length of the flow channel as well as the secondary inlet velocity and running time on the particle deposition pattern, the deposited particle mass and the cyclones’ performance were experimentally investigated, respectively. The results show that the ultrafine particles (Stokes number Stk < 0.0358) are mainly loose deposited on the walls under the secondary gas. Compare to the conventional cyclone with single tangential inlet, the total deposited particle mass of the improved cyclone has a maximum reduction more than 60%, and the collecting efficiency is increased up to 97.5% under the basically same pressure drop. The corresponding no-deposition area is increased by about 13%, and remains constant in spite of extending the running time. Moreover, an interesting phenomenon named “self-cleaning effect” of the vortex finder was captured for the gas cyclones, and mechanism of the secondary clean gas on the particle deposition is preliminarily analyzed. The results can deepen the understanding of the particle deposition on the vortex finder and guide the design of the anti-coking gas cyclones.

Deep Learning patterns of Aβ accumulation in Alzheimer’s Disease

AbstractBackgroundAccumulation of amyloid (Aß) plaques is an early pathologic change of Alzheimer’s Disease (AD). However, the mechanisms and pathways by which amyloid spreads across the cerebrum are not fully understood. Deriving distinct dimensions of amyloid deposition and their associations with biomedical factors could be useful to understand how amyloid propagates. In this analysis, we identified two distinct subtypes of progression based on spatiotemporal variations using a recently developed data‐driven, deep learning clustering method called Surreal‐GAN1.MethodWe used data from 482 A+ and 801 A‐ subjects with 18F‐florbetapir PET from the Alzheimer’s Disease Neuroimaging Initiative (ADNI; N = 832) and 11C‐PiB from the Preclinical AD consortium (PAC; N = 451). Standardized uptake value ratio (SUVR) maps (cerebellar GM reference) were transformed to reference space. We derived amyloid status using Gaussian mixture modelling of mean total cortical SUVR for each of 4 sites. We then applied non‐negative matrix factorization2 on the SUVR maps to identify data‐driven common patterns of deposition across the sample. Next, we applied Surreal‐GAN on a total of 1283 subjects to determine the amyloid spatiotemporal subtypes. Correlations with clinical and cognitive variables were evaluated.ResultsParticipants were 30%/22% female and had mean age 74.9 (±7.4)/ 67.9(±9.1) years for ADNI and PAC, respectively. We identified 24 components from NMF (Fig 1A) after excluding 6 as non‐target features. Surreal‐GAN showed optimal agreement indices for two patterns. While both patterns shared involvement of posterior cingulate/precuneus and inferior frontal cortex, pattern r1 shows relatively more occipital deposition and pattern r2 shows more frontal deposition (Fig 1B), as seen when comparing strongly r1 vs strongly r2 participants using voxel‐based morphometry (Fig 2). Both were associated with worse global cognitive function and worsening neurodegeneration (Table 1). r1 correlates with white matter hyperintensity volume, a measure of cerebrovascular disease, while pattern r2 is associated with the presence of APOE e4 alleles.ConclusionEmploying a data‐driven deep learning‐based approach, we derived more than one dissociable pattern of amyloid deposition, potentially differently influenced by vascular disease (r1/occipital) and genetics (r1/frontal). These findings could inform identification of subgroups of individuals who may or may not be responsive to particular clinical intervention.

Recent DIII-D progress toward validating models of tungsten erosion, re-deposition, and migration for application to next-step fusion devices

Fundamental mechanisms governing the erosion and prompt re-deposition of tungsten impurities in tokamak divertors are identified and analyzed to inform the lifetime of tungsten plasma-facing components in ITER and other future devices. Various experiments conducted at DIII-D to benchmark predictive models are presented, leveraging the DiMES removable sample exposure probe capability and the Metal Rings Campaign, in which toroidally symmetric rows of tungsten-coated tiles were installed in the DIII-D divertor. In tokamak divertors, the width of the electric sheath is of the order of the main ion Larmor radius, and a vast majority of sputtered tungsten impurities are typically ionized within the sheath. Therefore, W prompt redeposition is mainly governed by the ratio of the characteristic ionization mean-free path of neutral tungsten to the width of the sheath. In-situ monitoring of the prompt redeposition of tungsten impurities in divertors is demonstrated via the use of WII/WI line ratios and the ionizations/photon (S/XB) method in L-mode discharges. Even with this relatively limited set of emission measurements, net erosion measurements were found to be a consistent upper bound to an analytic scaling based on the ratio of the W ionization length, and the width of the magnetic sheath rather than the ratio of and the W+ gyro-radius. In the far-scrape-off layer (SOL) of the ITER divertor, however, it is calculated that the measurement of photon emissions associated with the ionization of tungsten impurities up to may be required. Finally, W deposition patterns on DiMES collector probes, interpreted via DIVIMP-WallDYN modelling, reveal the key roles of progressive W erosion/re-deposition staps and E × B drifts in regulating long-range high-Z material migration.

Impact аssessment of the September 2022 disaster in the area of Karavelovo, Bogdan, and Slatina villages, Karlovo Municipality

On September 2nd, 2022, an intense and prolonged rainfall event caused severe flooding, landslides, debris flows, and groundwater rise, resulting in substantial damage, particularly in the northern slopes of Sredna Gora Mountain in Central Bulgaria. Various methodologies, including field analysis, remote sensing, and GIS tools, were employed to analyze the disaster’s causes and field conditions. Active sediment sources, deposition patterns, and mapping techniques were used to document the disaster’s impact. The results showed that the disaster resulted from the formation of numerous landslides, and rapid hydrological response led to riverine flooding, high-speed flows, and sediment deposition. An important contribution of this study is the generated landslide inventory map, that can be used for mountain road reconstruction and the planning of mitigation measures.

Paleo-uplift forced regional sedimentary evolution: A case study of the Late Triassic in the southeastern Sichuan Basin, South China

The sedimentary environment of the Upper Triassic in the southeastern Sichuan Basin is obviously controlled by Luzhou paleo-uplift (LPU). However, the influence of paleo-uplift on the sedimentary patterns of the initial stages of this period in the southeastern Sichuan Basin has not yet been clear, which has plagued oil and gas exploration and development. This study shows that there is a marine sedimentary sequence, which is considered to be the first member of Xujiahe Formation (T3X1) in the southeastern Sichuan Basin. The development of LPU resulted in the sedimentary differences between the eastern and western Sichuan Basin recording T3X1 and controlled the regional sedimentary pattern. The western part is dominated by marine sediments, but the eastern paleo-uplift area is dominated by continental sedimentation in the early stage of T3X1, and it begins to transform into a marine sedimentary environment consistent with the whole basin in the late stage of the period recorded by the Xujiahe Formation. The evidences are as follows: (1) time series: based on the cyclostratigraphy analysis of Xindianzi section and Well D2, in the southeastern Sichuan Basin, the period of sedimentation of the Xujiahe Formation is about 5.9 Ma, which is basically consistent with the Qilixia section, eastern Sichuan basin, where the Xujiahe Formation is widely considered to be relatively complete; (2) distribution and evolution of palaeobiology: based on analysis of abundance evolution of major spore-pollen, many land plant fossils are preserved in the lower part of T3X1, indicates the sedimentary environment of continental facies. In the upper part of T3X1, the fossil of terrestrial plants decreased, while the fossil of marine and tidal environment appeared, this means that it was affected by the sea water in the late stages of T3X1; (3) geochemistry: calculate the salinity of water from element indicates that the uplift area is continental sedimentary environment in the early stage of T3X1, while the central and western areas of the basin are marine sedimentary environment. Until the late stage of T3X1, the southeast of the basin gradually turns into marine sedimentary environment, consisting with the whole basin; (4) types of kerogen: type Ⅲ kerogen representing continental facies was developed in the early stage of T3X1 in the uplift area, and type Ⅱ kerogen, representing marine facies, was developed in the late stage; while type Ⅱ kerogen was developed in the central and western regions of the basin as a whole in T3X1. This study is of great significance for understanding of both stratigraphic division and sedimentary evolution providing theoretical support for the exploration and development of oil and gas.

Examining the overlap between patterns of tau deposition and cortical neurite microstructure in preclinical Alzheimer’s disease

AbstractBackgroundIncreased Amyloid‐beta (Aβ) is associated with the neuropathological features of Alzheimer’s disease (AD), and it has been suggested to amplify tau spreading in the brain that leads to neurodegeneration. However, little is known about how the pattern of tau spreading overlaps with that of cortical microstructural neurodegeneration in the preclinical stages of the disease. Here, we utilized molecular imaging and neurite orientation dispersion and density imaging (NODDI) to identify the spreading pattern of tau pathology with the disease progression in cross‐sectional data and interaction with the degradation of cortical neurite microstructures.MethodsThe study consisted of normal controls (CN) and patients with mild cognitive impairments (MCI) from the Alzheimer’s Disease Neuroimaging Initiative (ADNI) (Table 1). All participants had structural and multi‐shell diffusion magnetic resonance imaging (MRI), and positron emission tomography (PET) scans using 18F‐florbetapir (AV45) for and 18F‐flortaucipir (AV1451) for tau. The preprocessed PET images were used to generate the standardized uptake value ratio (SUVR) values in each hemisphere consisting of 180 cerebral cortical brain regions defined by the Glasser atlas. The preprocessed dMRI data were used to compute cortical NODDI coefficients (neurite density (intracellular volume fraction; ICVF), orientation dispersion index (ODI), and isotropic volume fraction (FISO)). The tau and NODDI microstructural values are then normalized compared to the Aβ− CN group by adjusting the values for age and sex. The tau spreading order was defined based on the frequencies of the normalized tau values that exceeded the given threshold and compared the patterns with the neurite microstructures.ResultsWe found a sharp increase of tau deposition in patients with Aβ+ MCI, and the medial temporal regions were identified as the earliest region to become tau positive and continue to spread to inferior temporal and inferior parietal regions. Most importantly, we found significant patterns of cortical ODI degradation with the tau spreading in the right entorhinal cortex (p = 0.004) and the right hippocampus (p = 0.02).ConclusionThe findings of this cross‐sectional study provide that regional cortical neurite imaging could provide higher sensitivity to changes in the pathological process of tau spreading in tau epicenters in AD.