Migration Length Research Articles

Influence of surface morphology on erosion of plasma-facing components in H-mode plasmas of ASDEX Upgrade

• Net erosion of plasma-facing materials investigated at the outer strike-point region of the ASDEX Upgrade divertor during H-mode discharges with small and frequent ELMs. • Increasing surface roughness reduces net erosion but less than what is the case in l -mode. • Net-erosion rates are generally 2–5 times higher in H-mode than in l -mode. • Exposure in H-mode conditions results in strong local variations in the poloidal and toroidal erosion/deposition profiles. • Both erosion and deposition require detailed analyses at the microscopic scale and the deposition patterns may be drastically different for heavy and light impurities. • Local plasma parameters have a huge impact on PFC erosion rates and surface morphology and its temporal evolution have to be taken into account for quantitative estimates of erosion rates and PFC lifetime under reactor-relevant conditions. Net erosion of plasma-facing materials was investigated at the low-field-side (outer) strike-point area of the ASDEX Upgrade (AUG) divertor during H-mode discharges with small and frequent ELMs. To this end, Au and Mo marker samples with different surface morphologies and geometries were exposed to plasmas using the DIM-II divertor manipulator. The results were compared to existing erosion and deposition patterns from various L- and H-mode experiments, in the latter case the main difference was the size and frequency of the ELMs. We noticed that increasing surface roughness reduces net erosion but less than what is the case in L-mode. On the other hand, net-erosion rates in H-mode are generally 2–5 times higher than the corresponding L-mode values, in addition to which exposure in H-mode conditions results in strong local variations in the poloidal and toroidal erosion/deposition profiles. The latter observation we associate with the large migration length, on the order of several cm, of the eroded material, resulting in strong competition between erosion and re-deposition processes especially at poloidal distances > 50 mm from the strike point. Considerable net erosion was measured throughout the analysed poloidal region unlike in L-mode where the main erosion peak occurs in the vicinity of the strike point. We attribute this qualitative difference to the slow decay lengths of the plasma flux and electron temperature in the applied H-mode scenario. Both erosion and deposition require detailed analyses at the microscopic scale and the deposition patterns may be drastically different for heavy and light impurities. Generally, the rougher the surface the more material will accumulate on locally shadowed regions behind protruding surface features. However, rough surfaces also exhibit more non-uniformities in the quality or even integrity of marker coatings produced on them, thus complicating the analyses of the experimental data. We conclude that local plasma parameters have a huge impact on the PFC erosion rates and, besides incident plasma flux, surface morphology and its temporal evolution have to be taken into account for quantitative estimates of erosion rates and PFC lifetime under reactor-relevant conditions.

The Mechanisms of AlGaN Device Buffer Layer Growth and Crystalline Quality Improvement: Restraint of Gallium Residues, Mismatch Stress Relief, and Control of Aluminum Atom Migration Length

The mechanisms of AlGaN device buffer layer growth were studied. Gallium residues in the reactor chamber may be harmful to the quality of the AlN strain modulation layer, which eventually worsens the AlGaN buffer layer. By restraining the gallium residues, the crystalline quality of the AlGaN layer is markedly improved. In addition, enhancing stress relief in nucleation and coalescence stages will reduce the edge dislocations induced by strain relaxation in the 2D growth stage. A slower precursor flow rate can promote the stress relief in nucleation and coalescence stages. By comparison, a suitable suppression of Al atoms’ surface migration can decrease surface roughness, which can be realized by increasing the precursor flow rate. Eventually, we obtained a AlGaN buffer layer having both low edge dislocation density and a flat surface using a two-step growth method.

Experimental Measurement of Infinite Dilution Thermal Neutron Self-shielding Factor

The absorption of neutrons in media together with its transport properties cause the neutron flux to decrease as it penetrates the material because the absorption of neutrons in the sample itself attenuates the neutrons flux as it goes deeper into the sample. In the present work, the thermal neutron self-shielding factors of indium, gold, zinc, and mercury were determined experimentally. The current results together with those found in the literature were used to validate a mathematical ab initio formulae based on integral cross-section parameters used to compare our results. The complete agreement among these species of data suggests the validity of correlating the neutron migration length in the convex-shaped material with the average chord length described in the mathematical model.

Abstract 3459: Patient derived gliomaspheres exhibit HA concentration dependent invasiveness in 3D hydrogels

Abstract Hyaluronic acid (HA) is a highly abundant glycosaminoglycan within the central nervous system. In glioblastoma (GBM), interactions with HA mediate tumor cell invasion. An improved knowledge of the biological underpinnings of HA-dependent GBM cell migration can facilitate the development of efficacious therapeutics. To better study how HA in the tumor matrix affects invasion, we have developed a tunable, 3D culture system in which to study gliomaspheres (GSs) of patient-derived tumor cells. Photopolymerization (365 nm for 15 seconds) of GSs suspended in a solution 0.025 w/v% lithium phenyl-2,4,6-trimethylbenzoylphosphinate (LAP), thiolated 4-arm poly-ethylene glycol (20 kDa, Laysan Bio), 8-arm poly-ethylene glycol-norbornene (20 kDa, Laysan Bio), thiolated peptides containing an ‘RGD’ amino acid motif, and either 0.10, 0.25, 0.50, or 0.75 w/v% of thiolated HA (700 kDa average molecular weight, Lifecore Biomedical) yielded 3D hydrogels of varying HA concentrations and similar mechanical properties. Relative invasive capacity, quantified by shape factor (deviation from circularity) and migration length (maximum extension length of processes from the GS periphery), differed across patient lines and was independent of their Cancer Genome Atlas (TCGA) classification as either mesenchymal or proneural. Hydrogels with higher amounts of HA (>0.25% w/v) generally enhanced invasion as compared to low HA (0.10 w/v%) hydrogels. In certain cell lines, a biphasic relationship between HA concentration and migration was observed, in line with previous reports of CD44 expression and migration. Moreover, inhibition of the CD44-Ezrin-Actin axis, using NSC668394, reduced migratory activity in hydrogels with higher HA (>0.25% w/v), while slightly increasing invasion in hydrogels with low HA (0.10 w/v%). In sum, results demonstrate the use of a matrix-mimetic, 3D hydrogel system in which to study GBM invasion through the local extracellular matrix. Citation Format: Gevick Safarians, Itay Solomon, Alireza Sohrabi, Stephanie Seidlits. Patient derived gliomaspheres exhibit HA concentration dependent invasiveness in 3D hydrogels [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3459.

Neutron Response Modeling to Track Lean Gas Plume in Recycled Gas Cap Reservoir in Concurrent Gas Cap-Oil Rim Development: A Step Forward

Summary Gas cap pressure maintenance while developing the associated oil rim is a critical aspect for optimum recovery. Preventing gas cap pressure dropping below dewpoint by injecting lean gas is essential for concurrent gas cap-oil rim development. Reservoir heterogeneity aggravates lean gas override causing preferential movement of lean gas plume. Thus, it is important to track lean gas plume while recycling and understanding the breakthrough potential of lean gas. This paper demonstrates a new workflow to track lean gas plume by estimating phase saturations with a case study from one of the giant oil and gas fields, Onshore, Abu Dhabi. Pulsed neutron capture (PNC) tools are used for reservoir monitoring and surveillance. However, sigma log evaluation is insufficient to derive individual hydrocarbon phase saturations to monitor lean gas plume. Neutron response modeling (NRM) is devised to differentiate between lean and rich gas. NRM is a probabilistic solver with input of mineral and fluid phase parameters into tool response functions in petrophysical evaluation. To distinguish with discrete neutron fluid response between lean and rich gas, pressure/volume/temperature (PVT) data are utilized to derive hydrogen index, capture cross section, thermal decay length, and neutron macro parameters, such as neutron slowing down length and migration length. Neutron response is investigated for lean and rich gas with sensitivity of invasion effects on neutron log by calibrating to core porosity. The response for each phase under thermal neutron and capture modes with corresponding raw neutron log statistics is reviewed in both openhole and casedhole environments in known lean/rich gas intervals. Thirty-five wells spread across gas cap and oil leg with quality neutron log data are modeled and individual phase saturations are estimated. The target reservoir is under development with over three decades of lean gas injection to support oil production. NRM results and phase saturations are validated with recent formation sampling, which enhanced the confidence in the overall workflow. Later, the results are verified to be in excellent agreement with lean gas injection and production history of the target reservoir. The identified movement of lean gas highlights nonuniform geology and gravity segregation of injected lean gas into upper members of the target reservoir. The results also emphasized the need for better injection support to lower members of the target reservoir where gas cap development is ongoing. The solution presented is unique, particularly for lean gas injection projects by utilizing PVT for NRM based on neutron transport mechanism in pore fluids. Existing workflows require a special nuclear modeling platform with computationally expensive processing on data sets acquired using advanced logging technology. In spite of these prerequisites, existing workflows are not able to distinguish lean gas over rich gas. This paper effectively demonstrates NRM workflow distinguishing lean gas plume from rich gas using neutron logs and reveals compelling reservoir management insights. The sensitivity studies and practicality of this workflow highlight the fundamental importance of neutron logs in mature fields.

Antigenotoxic Effect of Ascorbic Acid and Resveratrol in Erythrocytes of Ambystoma mexicanum, Oreochromis niloticus and Human Lymphocytes Exposed to Glyphosate.

Glyphosate is a controversial herbicide. Its genotoxicity and presence in various ecosystems have been reported. The use of ascorbic acid and resveratrol could protect different organisms from glyphosate-induced genetic damage. In the present study, specific genetic damage induced by glyphosate was evaluated in erythrocytes of Oreochromis niloticus, Ambystoma mexicanum and human lymphocytes. Simultaneously, the antigenotoxic capacity of various concentrations of ascorbic acid and resveratrol was evaluated by means of pretreatment and simultaneous treatment protocols. The 0.03, 0.05 and 0.07 mM concentrations of glyphosate induced significant genotoxic activity (p < 0.05) in human lymphocytes and in erythrocytes of the species studied, and could cause genomic instability in these populations. The reduction in genetic damage observed in human lymphocytes exposed to high concentrations of glyphosate is only apparent: excessive genetic damage was associated with undetectable excessive tail migration length. A significant (p < 0.05) antigenotoxic effect of ascorbic acid and resveratrol was observed in all concentrations, organisms and protocols used. Both ascorbic acid and resveratrol play an important role in maintaining the integrity of DNA. Ascorbic acid in Oreochromis niloticus, Ambystoma mexicanum reduced glyphosate-induced genetic damage to a basal level. Therefore, our data indicate that these antioxidants could help preserve the integrity of the DNA of organisms exposed to glyphosate. The consumption of antioxidants is a useful tool against the genotoxicity of glyphosate.

Image-based migration velocity and dune length in clear water rivers

This work presents a novel way of measuring image-based migration velocity and dune length in clear water rivers. These results, together with empirical formulations, can be used to estimate bedload sediment transport with a high-spatial resolution. Image processing relies on the non-intrusive image-based technique called Space-Time Image Velocimetry (STIV). STIV consists in visualizing pixel intensity variation in time over a defined line. This technique was originally applied to hydraulics in order to characterize streamwise surface velocities in rivers. In this case, STIV is used to measure dune migration velocity and length in a shallow river with clear water in Córdoba Province, Argentina. Image processing procedures are detailed, including pre-processing and rectification. Results are then compared with measurements obtained from Acoustic Doppler Current Profilers. Finally, as an appendix, using the measured data and empirical equations, an estimation of bedload sediment transport is performed using both techniques.

Identification of genetic instability in peripheral blood lymphocyte of oral squamous cell carcinoma patients assess by comet assay.

Context:Studies established that human cancer is principally a genetic disease; it arises as accumulation of a set of genetic changes. In the pathogenesis of cancer, genetic instability is the sequential event to a carcinogenic stimulus resulting in various genomic changes including DNA damage.Aims:To assess genetic instability, as susceptibility to DNA damage, we used single-cell gel electrophoresis (comet assay) to study double strand breaks in associated with the risk of oral squamous cell carcinoma (OSCC).Materials and Methods:We used comet assay to measure double strand break in individual peripheral blood lymphocytes from 50 individuals with OSCC and 30 healthy control subjects. All personal information was gathered from subjects including tobacco history. DNA damage was visualized as comet assay and quantified by movement of damaged strands as length of tail.Results:Study results of OSCC patients were observed in relation to clinical staging and histological grading of carcinoma. On the basis of clinical observation, cases were grouped in to Stage I, Stage II, Stage III and Stage IV. No stage I cases were in study sample. The mean DNA damage migration length was observed 4.600 ± 0.4613 μm in stage II, whereas in Stage III and Stage IV, it was observed to be 4.961 ± 0.5620 μm and 4.883 ± 0.410 μm, respectively. The DNA damage length in histological grades of squamous cell carcinoma patients in Grade I was 4.6437 ± 0.3061 μm and Grade II was 5.3533 ± 0.3831 μm. In comparison with control group and squamous cell carcinoma group, it was observed in the range of 0.02–0.36 μm and varied from 4.04 to 5.84 μm range, respectively. Thus, the results were statistically significant with the histological grading of OSCC.Statistical Analysis:Unpaired' test and “ANOVA” test are used for statistics.Statistical Analysis:Unpaired' test and “ANOVA” test are used for statistics.Conclusion:The amount of DNA strand breaks in peripheral lymphocytes are measured by comet assay which is associated with relative risk of OSCC.

How Hole Injection Accelerates Both Ion Migration and Nonradiative Recombination in Metal Halide Perovskites

Ion migration, hole trapping, and electron-hole recombination are common processes in metal halide perovskites. We demonstrate using ab initio non-adiabatic molecular dynamics and time-domain density functional theory that they are intricately related and strongly influence each other. The hole injection accelerates ion migration by decreasing the diffusion barrier and shortening the migration length. The injected hole also promotes the nonradiative charge recombination by strengthening electron-phonon interactions in the low-frequency region and prolonging the quantum coherence time. The synergy stems from the soft perovskite lattice and response of the valence band maximum to the Pb-I lattice distortion induced by the hole. This work provides important insights into the influence of ion mobility and hole injection on the performance of perovskite solar cells and suggests that high concentration of holes should be avoided.

Shifts in phenology of autumn migration and wing length among reedbed passerines along the East Asian–Australasian Flyway

Climate change impacts bird migration phenology, causing changes in departure and arrival dates, leading to potential mismatches between migration and other key seasonal constraints. While the impacts of climate change on arrival at breeding grounds have been relatively well documented, little is known about the impacts of climate change on post-breeding migration, especially at stopover sites. Here we use long-term (11 years) banding data (11,118 captures) from 7 species at Mai Po Marshes Nature Reserve in Hong Kong, a key stopover site for migratory birds along the East Asian–Australasian Flyway, to describe long-term changes in migration phenology and to compare observed changes to annual weather variation. We also examine changes in wing length over a longer time period (1985–2020) as wing length often correlates positively with migration distance. We found that observed changes in migratory phenology vary by species; three species had later estimated arrival (by 1.8 days per year), peak (by 2.6 days per year) or departure (by 2.5 days per year), one showed an earlier peak date (by 1.8 days per year) and two showed longer duration of passage (2.7 days longer and 3.2 days longer per year). Three species exhibited no long-term change in migration phenology. For two of the four species with shifting phenology, temperature was an important predictor of changing peak date, departure dates and duration of passage. Wing length was shorter in three species and longer in two species, but these changes did not correlate with observed phenological changes. The complex changes observed here are indicative of the challenges concerning the detection of climate change in migratory stopover sites. Continued monitoring and a better understanding of the dynamics of all sites in the migratory pathway will aid conservation of these species under global change.

MicroRNA-140-3p represses the proliferation, migration, invasion and angiogenesis of lung adenocarcinoma cells via targeting TYMS (thymidylate synthetase)

ABSTRACT MicroRNA (miR)-140-3p has been proved to repress lung adenocarcinoma (LUAD), and our study aims to further evaluate the mechanism. Bioinformatic analyses were performed. The viability, proliferation, migration, invasion and angiogenesis of transfected LUAD cells were all determined via Cell Counting Kit-8, colony formation, Scratch, Transwell, and tube formation assays. The targeting relationship between miR-140-3p and thymidylate synthetase (TYMS) was confirmed by dual-luciferase reporter assay. Relative expressions of miR-140-3p, TYMS, epithelial-to-mesenchymal transition- (E-cadherin, N-cadherin, vimentin), angiogenesis- (vascular endothelial growth factor (VEGF)), and apoptosis-related factors (cleaved caspase-3, B-cell lymphoma-2 (Bcl-2), Bcl-2-associated X protein (Bax)) were quantified by quantitative real-time polymerase chain reaction or Western blot. TYMS was high-expressed yet miR-140-3p was low-expressed in LUAD cells. Upregulation of miR-140-3p inhibited TYMS expression, viability, colony formation, migration, invasion, and tube length within LUAD cells, while downregulation of miR-140-3p did oppositely. Silenced TYMS, the downstream target gene of miR-140-3p, reversed the effects of miR-140-3p downregulation on TYMS expression, cell viability, colony formation, migration, invasion, and tube length as well as the metastasis-, apoptosis- and angiogenesis-related proteins in LUAD cells. Upregulation of miR-140-3p inhibited the proliferation, migration, invasion and angiogenesis of LUAD cells via targeting TYMS.

Uranium migration through the Swiss Opalinus Clay varies on the metre scale in response to differences of the stability constant of the aqueous, ternary uranyl complex Ca&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt;UO&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt;(CO&amp;lt;sub&amp;gt;3&amp;lt;/sub&amp;gt;)&amp;lt;sub&amp;gt;3&amp;lt;/sub&amp;gt;

Abstract. The simulation of uranium migration through the Swiss Opalinus Clay is used as an example to quantify the influence of varying values of a stability constant in the underlying thermodynamic database on the migration lengths for the repository scale. Values for the stability constant of the neutral, ternary uranyl complex Ca2UO2(CO3)3 differ in literature by up to one order of magnitude. Within the studied geochemical system, either the neutral or the anionic complex CaUO2(CO3)32- is the predominant one, depending on the chosen value for the neutral complex. This leads to a changed interaction with the diffuse double layers (DDL) enveloping the clay minerals and thus can potentially influence the diffusive transport of uranium. Hence, two identical scenarios only differing in the value for the stability constant of the Ca2UO2(CO3)3 complex were applied in order to quantify and compare the migration lengths of uranium on the host rock scale (50 m) after a simulation time of one million years. We ran multi-component diffusion simulations for the shaly and sandy facies in the Opalinus Clay. A difference in the stability constant of 1.33 log units changes the migration lengths by 5 to 7 m for the sandy and shaly facies, respectively. The deviation is caused by the anion exclusion effect. However, with a maximum diffusion distance of 22 m, the influence of the stability constant of the Ca2UO2(CO3)3 complex on uranium migration in the Opalinus Clay is negligible on the host rock scale.

Hypoxic tubular epithelial cells regulate the angiogenesis of HMEC-1 cells via mediation of Rab7/MMP-2 axis.

Renal hypoxia is associated with persisting peritubular capillary rarefaction in progression of chronic kidney disease (CKD), and this phenomenon mainly resulted from the dysregulated angiogenesis. Rab7 is known to be involved in renal hypoxia. However, the mechanism by which Rab7 regulates the renal hypoxia remains unclear. Protein expression was detected by western blot. Cell proliferation was detected by EdU staining. Cell migration was tested by transwell assay. Rab7 was upregulated in HK-2 cells under hypoxia conditions. Hypoxia significantly inhibited the viability and proliferation of human microvascular endothelial cells (HMEC-1 cells), while this phenomenon was obviously reversed by Rab7 silencing. Consistently, Hypoxia significantly decreased the migration and tube length of HMECs, which was partially reversed by knockdown of Rab7. Moreover, hypoxia-induced inhibition of MMP2 activity was significantly rescued by knockdown of Rab7. Moreover, ARP100 (MMP-2 inhibitor) significantly reversed the effect of Rab7 shRNA on cell viability, migration and angiogenesis. Furthermore, knockdown of Rab7 significantly alleviated the fibrosis in tissues of mice. Knockdown of Rab7 significantly alleviated the renal hypoxia in chronic kidney disease through regulation of MMP-2. Thus, our study might shed new light on exploring the new strategies against CKD.

Ultrathin MoS2 nanosheet as co-catalyst coupling on graphitic g-C3N4 in suspension system for boosting photocatalytic activity under visible-light irradiation

In this study, ultrathin molybdenum disulfide (MoS2) nanosheets with thickness of 1.6–8.8 nm were obtained by liquid-phase exfoliating bulk MoS2. Then, they were employed as cocatalyst to build ultrathin MoS2/g-C3N4 heterojunction by self-assembly method. The degradation reaction of chlorimuron-methyl herbicide and tetracycline antibiotics under visible light was used to evaluate the photocatalytic properties of ultrathin MoS2/g-C3N4. The results showed that ultrathin MoS2/g-C3N4 composite exhibit superior photocatalytic performance. The MoS2/g-C3N4 composite with 15 wt% of ultrathin MoS2 nanosheet exhibited the highest degradation efficiency with 90.4% for chlorimuron-ethyl and 91.7% for tetracycline in 45 min under simulated sunlight, which was 8.8 times and 13.4 times than that of bare g-C3N4, respectively. The outstanding photocatalytic activity of ultrathin MoS2/g-C3N4 heterojunction thanks to the unique features of ultrathin MoS2 nanosheet that it harvesting the entire visible light, increasing the contact surface area with the support and shortened the electron and ion migration length, as well as more exposed edge sulfur atoms as redox centers. The radical scavenger experiments showed that •OH and •O2- plays a key role in the photocatalytic degradation process. This study provides a new idea for the design of high-activity a co-catalyst, that is, ultrathin MoS2 nanosheet has a significant influence on the photocatalytic performance of MoS2/g-C3N4 heterostructure photocatalyst.

Potential Uranium Migration within the Geochemical Gradient of the Opalinus Clay System at the Mont Terri

Transport properties of potential host rocks for nuclear waste disposal are typically determined in laboratory or in-situ experiments under geochemically controlled and constant conditions. Such a homogeneous assumption is no longer applicable on the host rock scale as can be seen from the pore water profiles of the potential host rock Opalinus Clay at Mont Terri (Switzerland). The embedding aquifers are the hydro-geological boundaries, that established gradients in the 210 m thick low permeable section through diffusive exchange over millions of years. Present-day pore water profiles were confirmed by a data-driven as well as by a conceptual scenario. Based on the modelled profiles, the influence of the geochemical gradient on uranium migration was quantified by comparing the distances after one million years with results of common homogeneous models. Considering the heterogeneous system, uranium migrated up to 24 m farther through the formation depending on the source term position within the gradient and on the partial pressure of carbon dioxide pCO2 of the system. Migration lengths were almost equal for single- and multicomponent diffusion. Differences can predominantly be attributed to changes in the sorption capacity, whereby pCO2 governs how strong uranium migration is affected by the geochemical gradient. Thus, the governing parameters for uranium migration in the Opalinus Clay can be ordered in descending priority: pCO2, geochemical gradients, mineralogical heterogeneity.

Recent Advances in Quantum Dots for Photocatalytic CO2 Reduction: A Mini-Review.

Solar energy–driven carbon dioxide (CO2) reduction to valuable solar fuels/chemicals (e.g., methane, ethanol, and carbon monoxide) using particulate photocatalysts is regarded as one of the promising and effective approaches to deal with energy scarcity and global warming. The growth of nanotechnology plays an eminent role in improving CO2 reduction (CO2R) efficiencies by means of offering opportunities to tailor the morphology of photocatalysts at a nanoscale regime to achieve enhanced surface reactivity, solar light absorption, and charge separation, which are decisive factors for high CO2R efficiency. Notably, quantum dots (QDs), tiny pieces of semiconductors with sizes below 20 nm, offering a myriad of advantages including maximum surface atoms, very short charge migration lengths, size-dependent energy band positions, multiple exciton generation effect, and unique optical properties, have recently become a rising star in the CO2R application. In this review, we briefly summarized the progress so far achieved in QD-assisted CO2 photoreduction, highlighting the advantages of QDs prepared with diverse chemical compositions such as metal oxides, metal chalcogenides, carbon, metal halide perovskites, and MXenes.

Impact of Hydrostratigraphic Continuity on Brine‐to‐Freshwater Interface Dynamics: Implications From a Two‐Dimensional Parametric Study in an Arid and Endorheic Basin

AbstractDespite the prevalence of density‐dependent flow systems in the brine‐rich aquifers of arid climates and coastal aquifers, the impact of realistic geologic conditions on interface geometry and density‐dependent time‐sensitive dynamics remains poorly constrained. Salar de Atacama provides an analog for exploring interface dynamics in arid regions. A site‐specific two‐dimensional hydrostratigraphic interpretation is used to examine the dynamics of the brine‐to‐freshwater interface. With the same simulation framework and core data, a separate parametric series of hydraulic conductivity distributions with varying horizontal continuity provides a mechanistic explanation for observed dynamics. Comparing modeled interfaces and their sensitivity to perturbations in recharge in each realization yields insight into interface dynamics coupled with horizontal continuity in subsurface heterogeneity. Recharge fluctuation is introduced to each distribution following the interface reaching a dynamic steady state. Metrics for results evaluation include interface slope geometry, interface width, migration length, and response rate. Analyses suggest that the average slope of the modeled interface shallows by 0.01 and 0.05 m ⋅ m−1for an increase in continuity of highly permeable pathways by a factor of two and three, respectively. Increasing continuity also increases the overall response times and the variability in response. Results indicate that accurate representations of transient dynamics in modeling density‐dependent brine‐to‐freshwater interface dynamics requires the consideration of heterogeneity, as saline intrusion in the highest continuity group extends over twice as far on average and the modeled interface takes over 43% more time on average to reach a new dynamic steady state when compared to their homogeneous counterparts.

Three-dimensional evaluation of the coccyx movement between supine and standing positions using conventional and upright computed tomography imaging

Currently, no three-dimensional reference data exist for the normal coccyx in the standing position on computed tomography (CT); however, this information could have utility for evaluating patients with coccydynia and pelvic floor dysfunction. Thus, we aimed to compare coccygeal parameters in the standing versus supine positions using upright and supine CT and evaluate the effects of sex, age, and body mass index (BMI) on coccygeal movement. Thirty-two healthy volunteers underwent both upright (standing position) and conventional (supine position) CT examinations. In the standing position, the coccyx became significantly longer and straighter, with the tip of the coccyx moving backward and downward (all p < 0.001). Additionally, the coccygeal straight length (standing/supine, 37.8 ± 7.1/35.7 ± 7.0 mm) and sacrococcygeal straight length (standing/supine, 131.7 ± 11.2/125.0 ± 10.7 mm) were significantly longer in the standing position. The sacrococcygeal angle (standing/supine, 115.0 ± 10.6/105.0 ± 12.5°) was significantly larger, while the lumbosacral angle (standing/supine, 21.1 ± 5.9/25.0 ± 4.9°) was significantly smaller. The migration length of the tip of the coccyx (mean, 7.9 mm) exhibited a moderate correlation with BMI (r = 0.42, p = 0.0163). Our results may provide important clues regarding the pathogenesis of coccydynia and pelvic floor dysfunction.

An early cell shape transition drives evolutionary expansion of the human forebrain

SummaryThe human brain has undergone rapid expansion since humans diverged from other great apes, but the mechanism of this human-specific enlargement is still unknown. Here, we use cerebral organoids derived from human, gorilla, and chimpanzee cells to study developmental mechanisms driving evolutionary brain expansion. We find that neuroepithelial differentiation is a protracted process in apes, involving a previously unrecognized transition state characterized by a change in cell shape. Furthermore, we show that human organoids are larger due to a delay in this transition, associated with differences in interkinetic nuclear migration and cell cycle length. Comparative RNA sequencing (RNA-seq) reveals differences in expression dynamics of cell morphogenesis factors, including ZEB2, a known epithelial-mesenchymal transition regulator. We show that ZEB2 promotes neuroepithelial transition, and its manipulation and downstream signaling leads to acquisition of nonhuman ape architecture in the human context and vice versa, establishing an important role for neuroepithelial cell shape in human brain expansion.

Engineering study on lithium isotope separation by ion exchange chromatography

We have been studying the lithium isotope separation by ion exchange chromatography for the engineering development. We performed the lithium isotope separation experiments by chromatography. From the results, we estimated the migration lengths required to obtain the 20 %, 50 %, and 90 % enriched lithium-6, the required lengths are 340, 1600, and 5800 m, respectively. We studied the detection methods of lithium adsorption band boundary in order to design the circular type chromatographic equipment, which type equipment is required for the industrial plant. Based on these investigations, we designed the automatic circular type chromatographic equipment with the boundary interface detector and manufactured the prototype equipment.