Directional Migration Research Articles

Micro-tensile rheology of fibrous gels quantifies strain-dependent anisotropy

Semiflexible fiber gels such as collagen and fibrin have unique nonlinear mechanical properties that play an important role in tissue morphogenesis, wound healing, and cancer metastasis. Optical tweezers microrheology has greatly contributed to the understanding of the mechanics of fibrous gels at the microscale, including its heterogeneity and anisotropy. However, the explicit relationship between micromechanical properties and gel deformation has been largely overlooked. We introduce a unique gel-stretching apparatus and employ it to study the relationship between microscale strain and stiffening in fibrin and collagen gels, focusing on the development of anisotropy in the gel. We find that gels stretched by as much as 15 % stiffen significantly both in parallel and perpendicular to the stretching axis, and that the parallel axis is 2–3 times stiffer than the transverse axis. We also measure the stiffening and anisotropy along bands of aligned fibers created by aggregates of cancer cells, and find similar effects as in gels stretched with the tensile apparatus. Our results illustrate that the extracellular microenvironment is highly sensitive to deformation, with implications for tissue homeostasis and pathology. Statement of significanceThe inherent fibrous architecture of the extracellular matrix (ECM) gives rise to unique strain-stiffening mechanics. The micromechanics of fibrous networks has been studied extensively, but the deformations involved in its stiffening at the microscale were not quantified. Here we introduce an apparatus that enables measuring the deformations in the gel as it is being stretched while simultaneously using optical tweezers to measure its microscale anisotropic stiffness. We reveal that fibrin and collagen both stiffen dramatically already at ∼10 % deformation, accompanied by the emergence of significant, yet moderate anisotropy. We measure similar stiffening and anisotropy in the matrix remodeled by the tensile apparatus to those found between cancer cell aggregates. Our results emphasize that small strains are enough to introduce substantial stiffening and anisotropy. These have been shown to result in directional cell migration and enhanced force propagation, and possibly control processes like morphogenesis and cancer metastasis.

Construction of AgI/PCN-224 Z-scheme heterojunction for efficient photocatalytic degradation of tetracycline hydrochloride: Pathways, mechanism and theoretical calculations

The construction of heterojunction structures is pivotal in enhancing carrier separation and photocatalytic activity. Hence, AgI/PCN-224 (APN-x composites) Z-scheme heterojunctions were successfully synthesised using an in-situ precipitation method. The direction of electron migration and the band structures of APN-x were comprehensively investigated using a combination of experimental approaches and density functional theory (DFT) calculations. Owing to the extensive visible-light absorption capabilities of PCN-224 and the high efficiency of photogenerated carrier separation in the Z-scheme heterojunction, the optimally developed APN-3 photocatalyst demonstrated exceptional photodegradation efficiency for tetracycline hydrochloride (TCH). The removal rate of TCH by APN-3 within 120 min reached 91.56%, approximately 4.64 times higher than that achieved by pure AgI. The photocatalytic degradation mechanism was explored using free radical trapping experiments, electron spin resonance (ESR) technology and band structure analysis. Degradation pathways and intermediate products were investigated using liquid chromatography–tandem mass spectrometry (LC–MS).

Tracing Oils and Gas Accumulation in Complex Petroleum Systems Based on Biomarkers, Light Hydrocarbons, and Diamondoids from Concomitant Crude Oils: A Case Study in the Shawan Sag of the Junggar Basin, NW China.

The Shawan Sag is one of the most promising blocks in the western Junggar Basin for natural gas and oil exploration. To date, the research and exploration degree here is still low, and there is limited understanding of the origin and migration of natural gas and oils, which seriously restricts future exploration and development. At least three oil charging episodes and one gas charging episode could be confirmed in the reservoirs on the western slope of the Shawan Sag based on the analysis of concentrations and ratios of hopanes and steranes, diamondoids, and light hydrocarbons. The first and second charging oils originated from the peak and late oil generation window stages of Lower Permian Fengcheng Formation (P1f) source rocks, respectively. The third charging oil originated from the late oil generation window stage of source rocks of the Middle Permian lower Wuerhe Formation (P2w). Combining the carbon isotopic compositions and the gas composition, the fourth charging gas was derived from the postmature source rocks of Carboniferous(C) and Lower Permian Jiamuhe Formation (P1j) and the high-postmature source rock of Lower Permian Fengcheng Formation (P1f). The preservation conditions of nature gas in the Mesozoic (T-K) cap rocks in the Shawan Sag, as indicated by methyladamantanes (MAs)/methyldiamantanes (MDs) ratio, are better than those in the Mahu Sag. In this study, the methyladamantane maturity parameters of oils in the reservoirs were proposed to evaluate the maturity and further determine the migration direction of late-charging natural gas. The results suggest that late postmatured natural gases were charged from the southern part to the northwest of the Shawan Sag. Therefore, the southeastern direction of Well SP1 is a favorable area for natural gas exploration in the Shawan Sag. Meanwhile the northern part of the sag is favorable for the exploration of high-mature oil generated from source rocks within the Middle Permian Lower Wuerhe Formation.

Conserved DNA sequence analysis reveals the phylogeography and evolutionary events of Akebia trifoliata in the region across the eastern edge of the Tibetan Plateau and subtropical China

BackgroundThe eastern edge of the Qinghai‒Tibet Plateau (QTP) and subtropical China have various regions where plant species originate and thrive, but these regions have been the focus of very few integrative studies. Here, we elucidated the phylogeographic structure of a continuous and widespread Akebia trifoliata population across these two regions.ResultsSixty-one populations consisting of 391 genotypes were examined to assess population diversity and structure via network distribution analysis, maximum likelihood phylogenetic tree reconstruction, divergence time estimation, demographic history inference, and ancestral area reconstruction of both conserved internal transcribed spacer (ITS) and chloroplast (rps16) DNA sequences. The results showed that the ITS region was more variable than the rps16 region and could be suitable for studying intraspecific phylogeography. The A. trifoliata population displayed high genetic diversity, genetic differentiation and obvious phylogeographical structure, possibly originating on the eastern QTP, expanding during the last glacial-interglacial cycle, diverging in the early Pleistocene and middle Pleistocene, and extensively migrating thereafter. The migration route from west to east along rivers could be largely responsible for the long-distance dispersal of this species, while three main refuges (Qinba Mountains, Nanling Mountains and Yunnan-Guizhou Plateau) with multiple ice shelters facilitated its wide distribution.ConclusionsOur results suggested that the from west to east long migration accompanying with the minor short reciprocal migration in the south-north direction, and the three main refuges (the Qinba Mountains, Nanling Mountains and Yunnan-Guizhou Plateau) contributed to the extant geographical distribution of A. trifoliata. In addition, this finding also strongly reduced the discrepancy between glacial contraction and postglacial expansion and the in situ survival hypothesis by simultaneously considering the existence of many similar climate-related ecological niches and migration influences.

Open-Top Patterned Hydrogel-Laden 3D Glioma Cell Cultures for Creation of Dynamic Chemotactic Gradients to Direct Cell Migration.

The laminar flow profiles in microfluidic systems coupled to rapid diffusion at flow streamlines have been widely utilized to create well-controlled chemical gradients in cell cultures for spatially directing cell migration. However, within hydrogel-based closed microfluidic systems of limited depth (≤0.1 mm), the biomechanical cues for the cell culture are dominated by cell interactions with channel surfaces rather than with the hydrogel microenvironment. Also, leaching of poly(dimethylsiloxane) (PDMS) constituents in closed systems and the adsorption of small molecules to PDMS alter chemotactic profiles. To address these limitations, we present the patterning and integration of a PDMS-free open fluidic system, wherein the cell-laden hydrogel directly adjoins longitudinal channels that are designed to create chemotactic gradients across the 3D culture width, while maintaining uniformity across its ∼1 mm depth to enhance cell-biomaterial interactions. This hydrogel-based open fluidic system is assessed for its ability to direct migration of U87 glioma cells using a hybrid hydrogel that includes hyaluronic acid (HA) to mimic the brain tumor microenvironment and gelatin methacrylate (GelMA) to offer the adhesion motifs for promoting cell migration. Chemotactic gradients to induce cell migration across the hydrogel width are assessed using the chemokine CXCL12, and its inhibition by AMD3100 is validated. This open-top hydrogel-based fluidic system to deliver chemoattractant cues over square-centimeter-scale areas and millimeter-scale depths can potentially serve as a robust screening platform to assess emerging glioma models and chemotherapeutic agents to eradicate them.

Integrating ecosystem service value in the disclosure of landscape ecological risk changes: a case study in Yangtze River Economic Belt, China

Urban expansion and inappropriate land uses have caused a decline in the regional ecosystem services capacity, which is contrary to United Nations’ Sustainable Development Goal (SDG) 15 aiming to protect and promote sustainable use of terrestrial ecosystems. Landscape ecological risk (LER) visually depicts the disturbances to ecosystem services and environmental shifts resulting from human activities. Consideration of ecosystem services in LER assessment has not been sufficiently researched. Here, we employed ecosystem service values (ESV) to define landscape vulnerability, and adopted an enhanced risk assessment framework, amalgamating landscape patterns and ecosystem processes, to evaluate the spatial-temporal shifts in ESV and LER in the Yangtze River Economic Belt (YREB) from 2000 to 2020. We attempted to analyze the relationship between LER and anthropogenic disturbances. The results showed that over the past 20 years, the general trend revealed a diminishing high-risk area, while medium and low-risk regions expanded. Notably, the urban agglomeration of the YREB experienced a marked surge in risk. Regarding migration direction, the low-risk category has expanded in the east–west direction, while the medium and high-risk categories have shown inward contraction mainly in the north–south direction. The findings highlight the complex changes between ecological processes and LER under anthropogenic disturbances, and can serve as a guide for sustainable risk management and the development of ecological security patterns.

Photothermal and pyroelectric effects in hollow FeS2/CdS nanocomposites for enhanced photocatalytic hydrogen evolution

In this paper, a hollow structure of FeS2/CdS is designed to improve the photocatalytic generation of hydrogen by capitalizing on the synergistic interplay between the photothermal effect of FeS2 and the pyroelectric effect of CdS. The heat generated by the photothermal effect of FeS2 provides the hot end for the pyroelectric effect of CdS, and the condensate in the photocatalytic system provides the cold end. CdS undergoes spontaneous polarization and a thermoelectric impact in response to temperature fluctuations (ΔT), releasing surface charges. This process effectively governs the direction and rate of carrier migration within the FeS2 nanoparticles. The hydrogen production test demonstrates that FeS2/CdS-3 exhibited a hydrogen production rate of 154.0 μmol·g−1·h−1, which is 5.8 times higher than that of FeS2 (23.4 μmol·g−1·h−1), and it has excellent cycle stability. Furthermore, characterization through ultraviolet–visible spectroscopy, photoluminescence, electrochemical impedance spectroscopy, and linear sweep voltammetry confirms the outstanding carrier migration capability of the composite photocatalyst.

Transforaminal endoscopic lumbar discectomy with two-segment foraminoplasty for the treatment of very highly migrated lumbar disc herniation: a retrospective analysis.

The surgical resection of very highly migrated lumbar disc herniation (VHM-LDH) is technically challenging owing to the absence of technical guidelines. Hence, in the present study, we introduced the transforaminal endoscopic lumbar discectomy (TELD) with two-segment foraminoplasty to manage VHM-LDH and evaluated its radiographic and midterm clinical outcomes. The present study is a retrospective analysis of 33 consecutive patients with VHM-LDH who underwent TELD with two-segment foraminoplasty. The foraminoplasty was performed on two adjacent vertebrae on the basis of the migration direction of disc fragments to fully expose the disc fragments and completely decompress the impinged nerve root. The operation duration, blood loss, intra- and postoperative complications, and recurrences were recorded. Additionally, imageological observations were evaluated immediately after the procedure via magnetic resonance image and computerized tomography. Clinical outcomes were evaluated by calculating the visual analog scale (VAS) score and Oswestry Disability Index (ODI). The MacNab criterion was reviewed to assess the patients' opinions on treatment satisfaction. The resection rate of bony structures were quantitatively evaluated on postoperative image. The segmental stability was radiologically evaluated at least a year after the surgery. Additionally, surgery-related and postoperative complications were evaluated. The average age of the patients was 56.87 ± 7.77 years, with a mean follow-up of 20.95 ± 2.09 months. The pain was relieved in all patients immediately after the surgery. The VAS score and ODI decreased significantly at each postoperative follow-up compared with those observed before the surgery (P < 0.05). The mean operation duration, blood loss, and hospital stay were 56.17 ± 16.21min, 10.57 ± 6.92 mL, and 3.12 ± 1.23 days, respectively. No residual disc fragments, iatrogenic pedicle fractures, and segmental instability were observed in the postoperative images. For both up- and down- migrated herniation in the upper lumbar region, the upper limit value of resection percentage for the cranial SAP, caudal SAP, and pedicle was 33%, 30%, and 34%, respectively; while those in the lower lumbar region was 42%, 36%, and 46%, respectively. At the last follow-up, the satisfaction rate of the patients regarding the surgery was 97%. Surgery-related complications including dural tear, nerve root injury, epidural hematoma, iatrogenic pedicle fractures, and segmental instability were not observed. One patient (3%) suffered from the recurrence of LDH 10 months after the initial surgery and underwent revision surgery. The TELD with two-segment foraminoplasty is safe and effective for VHM-LDH management. Proper patient selection and efficient endoscopic skills are required for applying this technique to obtain satisfactory outcomes.

Positive and negative durotaxis - mechanisms and emerging concepts.

Cell migration is controlled by the coordinated action of cell adhesion, cytoskeletal dynamics, contractility and cell extrinsic cues. Integrins are the main adhesion receptors to ligands of the extracellular matrix (ECM), linking the actin cytoskeleton to the ECM and enabling cells to sense matrix rigidity and mount a directional cell migration response to stiffness gradients. Most models studied show preferred migration of single cells or cell clusters towards increasing rigidity. This is referred to as durotaxis, and since its initial discovery in 2000, technical advances and elegant computational models have provided molecular level details of stiffness sensing in cell migration. However, modeling has long predicted that, depending on cell intrinsic factors, such as the balance of cell adhesion molecules (clutches) and the motor proteins pulling on them, cells might also prefer adhesion to intermediate rigidity. Recently, experimental evidence has supported this notion and demonstrated the ability of cells to migrate towards lower rigidity, in a process called negative durotaxis. In this Review, we discuss the significant conceptual advances that have been made in our appreciation of cell plasticity and context dependency in stiffness-guided directional cell migration.

3D printing of PEGDA/bioceramic for guiding cell adhesion and migration

The adhesion and migration characteristics of osteocytes on the surface of bone materials are crucial for bone tissue regeneration, which is conducive to the directional repair of bone defects. Herein, the adhesion and migration characteristics of MC3T3-E1 cells on the surface of SLA-3D printed PEGDA/bioceramic materials were analyzed in detail. The results indicated that, in comparison to the cured PEGDA matrix, the pseudopods of cells preferred to adhere to ceramic particles, demonstrating the characteristics of hard drive migration. Furthermore, on a wavy surface with a surface roughness (Ra=2 μm) fabricated by the laser of the SLA-3D printer, MC3T3-E1 cells could grow directionally along the rough channel via contact guidance. Therefore, by controlling the distribution of ceramic particles and adjusting the surface morphology of the printed PEGDA/bioceramic materials, the migration direction of cells can be dominated, which is of great significance for the targeted repair of bone tissue.

Tnfaip8 and Tipe2 Gene Deletion Ameliorates Immediate Proteoglycan Loss and Inflammatory Responses in the Injured Mouse Intervertebral Disc.

TNFAIP8 and TIPE2 belong to TNFa-induced protein 8 (TNFAIP8/TIPE) family. They control apoptosis and direct leukocyte migration. Nucleus pulposus cell loss is a hallmark of intervertebral disc degeneration in response to injury, and inflammation may cause pain. Here, we examined the effects of TNFAIP8/TIPE2 deficiency on the intervertebral discs in mice with these genes deleted. Tail intervertebral discs in Tnfaip8 or Tipe2 single and double knockout mice ( Tnfaip8 -/- , Tipe2 -/- , and Tnfaip8/Tipe2 dko) , and wild-type controls were injured. The spine motion segments were stained with safranin O to reveal proteoglycans. Macrophages were identified by immunostaining, and selected inflammatory marker and collagen gene expression was examined by Real Time PCR. The injured tail intervertebral discs of Tnfaip -/- , Tipe2 -/- , and Tnfaip8/Tipe2 dko mice all displayed higher levels of proteoglycans than wild-type controls. Fewer macrophages were found in the injured intervertebral discs of Tipe2 -/- and Tnfaip8/Tipe2 dko mice than wild type. Il6 , Adam8 , and Col1 gene expression was downregulated in the injured intervertebral discs of Tnfip8/Tipe2 dko mice. TNFAIP8 and TIPE2 loss of function ameliorated proteoglycan loss and inflammation in the injured intervertebral discs. They may serve as molecular targets to preserve disc structure and reduce inflammation.

Biomimetically ordered ultralong hydroxyapatite nanowires-based hierarchical hydrogel scaffold with osteoimmunomodulatory and osteogenesis abilities for augmenting bone regeneration

Artificial construction of tissue engineering implants with bone-mimicking structure and osteogenic function is of great significance for bone regeneration, but it remains a formidable challenge. Herein, inspired by natural bone, a biomimetically hierarchical hydrogel scaffold with highly ordered arrangement and multi-layered concentric circular structure is constructed by a convenient free-injection method for osteoimmunomodulation and bone defect regeneration. Ultralong hydroxyapatite nanowires act as skeleton unit to assemble into the hierarchically ordered nanowire bundles and further hybridization with hyaluronic acid methacrylate and loading with layered double hydroxide nanosheets to form the stable biomimetic scaffold. The biomimetic scaffold exhibits anisotropic structure, high water content and porosity, mechanical robustness, and sustained release of bioactive ions. In particular, the excellent biocompatibility together with ordered topography and biochemical cue can guide recruitment and directional migration of stem cells, and effectively promote osteogenic differentiation and vascularization in vitro. Moreover, the biomimetic scaffold induces M2 phenotype polarization of macrophages, thus creating a favorable osteoimmune environment. The in vivo study proves that the biomimetic scaffold can attenuate inflammation, promote vascularized ossification, and further accelerate new bone formation. This study provides an innovative strategy to construct multifunctional anisotropic biomaterials for bone tissue engineering.

Biointerfaces with ultrathin patterns for directional control of cell migration

In the context of wound healing and tissue regeneration, precise control of cell migration direction is deemed crucial. To address this challenge, polydimethylsiloxane (PDMS) platforms with patterned 10 nm thick TiOx in arrowhead shape were designed and fabricated. Remarkably, without tall sidewall constraints, MC3T3-E1 cells seeded on these platforms were constrained to migrate along the tips of the arrowheads, as the cells were guided by the asymmetrical arrowhead tips which provided large contact areas. To the best of our knowledge, this is the first study demonstrating the use of thin TiOx arrowhead pattern in combination with a cell-repellent PDMS surface to provide guided cell migration unidirectionally without tall sidewall constraints. Additionally, high-resolution fluorescence imaging revealed that the asymmetrical distribution of focal adhesions, triggered by the patterned TiOx arrowheads with arm lengths of 10, 20, and 35 μm, promoted cell adhesion and protrusion along the arrowhead tip direction, resulting in unidirectional cell migration. These findings have important implications for the design of biointerfaces with ultrathin patterns to precisely control cell migration. Furthermore, microelectrodes were integrated with the patterned TiOx arrowheads to enable dynamic monitoring of cell migration using impedance measurement. This microfluidic device integrated with thin layer of guiding pattern and microelectrodes allows simultaneous control of directional cell migration and characterization of the cell movement of individual MC3T3-E1 cells, offering great potential for the development of biosensors for single-cell monitoring.

Benzocarbazole and methylxanthone molecular migration tracers unravel migration routes and filling history of Veslefrikk, Oseberg-East and Brage reservoirs in the Norwegian North Sea

Identification of petroleum migration routes and reservoir filling processes is feasible by applying carbazoles or xanthones as molecular migration tracers. To verify their utility, a well-constrained migration route was chosen for this study: the petroleum migration along the Veslefrikk and Oseberg East fields until reaching the Statfjord Formation compartment within the Brage field in the Norwegian North Sea. This migration route comprises an ideal test case because the oil is sourced from the same kitchen area, yielding very similar oil families in all three fields, and because the maturity remains within the main oil window, below 0.9 Ro % vitrinite reflectance equivalence.Different methodologies applied by two laboratories, from sample preparation to analytical methods, yielded identical results of migration direction and route using the benzocarbazole ratio ([a]/([a]+[c]), thus underlining practicability and robustness of this molecular migration parameter. The benzocarbazole ratio (BCR) in this study was neither affected by source rock facies, and/or biodegradation. A thermal maturity effect on BCR is considered here to be of only subordinate impact whereas it substantially affects benzocarbazole concentrations. The BCR declined from values of 0.68 at onset of migration to 0.42 at end of migration, whereby the absolute concentrations of benzocarbazoles in parallel declined by a factor of 10, from 5000 to 500 ng/g oil. The distribution and concentration of methylxanthones evolved comparable to that of benzocarbazoles. The methylxanthones ratios (MXR) from onset of migration until reaching the Brage field declined from a value of 0.85 to 0.42. The benzocarbazoles and methylxanthones, like other geo/biomarkers, preferentially reflect the first charge of the most polar and least mature oil delivered upon petroleum migration and could help to understand the reservoir filling history.Migrating oils derived from the Sogn Graben kitchen entered the Veslefrikk oil field first and continued until the structure was filled to spill point. Thereafter, migration continued to the Oseberg East oil field and after reaching spill point there it continued to the Brage field and its Statfjord formation compartment. The complex migration route represents a classical fill to spill scenario and benzocarbazole fractionation upon migration delineates the initial filling trends. The maturity values of crude oils are in the mid-oil window and show trends of covariance with the molecular migration indicators, thus proving to be supporting tracers in a classical fill to spill scenario, where maturity values are lowest when migration distances are greatest. This is due to the first expelled oil being of lowest thermal maturity entering the nearest reservoir first and then being displaced into farther reservoirs along the migration route upon arrival of later oil (more mature) charges.

PIEZO1 regulates leader cell formation and cellular coordination during collective keratinocyte migration.

The collective migration of keratinocytes during wound healing requires both the generation and transmission of mechanical forces for individual cellular locomotion and the coordination of movement across cells. Leader cells along the wound edge transmit mechanical and biochemical cues to ensuing follower cells, ensuring their coordinated direction of migration across multiple cells. Despite the observed importance of mechanical cues in leader cell formation and in controlling coordinated directionality of cell migration, the underlying biophysical mechanisms remain elusive. The mechanically-activated ion channel PIEZO1 was recently identified to play an inhibitory role during the reepithelialization of wounds. Here, through an integrative experimental and mathematical modeling approach, we elucidate PIEZO1's contributions to collective migration. Time-lapse microscopy reveals that PIEZO1 activity inhibits leader cell formation at the wound edge. To probe the relationship between PIEZO1 activity, leader cell formation and inhibition of reepithelialization, we developed an integrative 2D continuum model of wound closure that links observations at the single cell and collective cell migration scales. Through numerical simulations and subsequent experimental validation, we found that coordinated directionality plays a key role during wound closure and is inhibited by upregulated PIEZO1 activity. We propose that PIEZO1-mediated retraction suppresses leader cell formation which inhibits coordinated directionality between cells during collective migration.

Electrically induced directional ion migration in two-dimensional perovskite heterostructures

Electrically induced directional ion migration in two-dimensional perovskite heterostructures

In-situ construction of 1D β-FeOOH nanobelts/2D porous g-C3N4 heterojunction for enhanced “signal-on” photoelectrochemical aptasensing

Bisphenol A (BPA), a prevalent organic pollutant found in wastewater environment, is notorious for its resistance to natural degradation, raising significant ecological and human health concerns. In this study, a “signal-on” photoelectrochemical aptasensing system was designed for detecting BPA in real water samples with high specificity and sensitivity. One-dimensional (1D) β-FeOOH nanobelts were synthesized on a two-dimensional (2D) porous carbon nitride (g-C3N4) through an in-situ growth procedure. The β-FeOOH/g-C3N4 nanocomposites demonstrated superior photoelectric conversion efficiency due to several factors: (i) The 1D nanobelt-like structure of β-FeOOH shortens the charge transfer path within the nanocomposite, enabling directional and rapid migration of photoinduced charges from the interior to the surface. (ii) β-FeOOH possesses strong visible absorption capabilities, enhancing the utilization of g-C3N4 under photoexcitation, resulting in the generation of numerous photo-induced carriers. (iii) The in-situ formation of the β-FeOOH/g-C3N4 heterojunction establishes an intimate interfacial contact, facilitating the rapid separation and transfer of charges between β-FeOOH and g-C3N4. A photoelectrochemical aptasensing platform based on the photoactive material of β-FeOOH/g-C3N4 detects BPA with reduced photocurrent owing to the presence of BPA-aptamer macromolecules on the electrode surface. This BPA detection system exhibits excellent linearity over a wide concentration range from 10 pM to 10 nM, with high sensitivity (a detection limit of 3.5 pM), stability, specificity, and repeatability. Furthermore, this research offers a straightforward and rapid sensing platform for monitoring BPA enriched water environments.

Oleate Promotes Triple-Negative Breast Cancer Cell Migration by Enhancing Filopodia Formation through a PLD/Cdc42-Dependent Pathway.

Breast cancer, particularly triple-negative breast cancer (TNBC), poses a global health challenge. Emerging evidence has established a positive association between elevated levels of stearoyl-CoA desaturase 1 (SCD1) and its product oleate (OA) with cancer development and metastasis. SCD1/OA leads to alterations in migration speed, direction, and cell morphology in TNBC cells, yet the underlying molecular mechanisms remain elusive. To address this gap, we aim to investigate the impact of OA on remodeling the actin structure in TNBC cell lines, and the underlying signaling. Using TNBC cell lines and bioinformatics tools, we show that OA stimulation induces rapid cell membrane ruffling and enhances filopodia formation. OA treatment triggers the subcellular translocation of Arp2/3 complex and Cdc42. Inhibiting Cdc42, not the Arp2/3 complex, effectively abolishes OA-induced filopodia formation and cell migration. Additionally, our findings suggest that phospholipase D is involved in Cdc42-dependent filopodia formation and cell migration. Lastly, the elevated expression of Cdc42 in breast tumor tissues is associated with a lower survival rate in TNBC patients. Our study outlines a new signaling pathway in the OA-induced migration of TNBC cells, via the promotion of Cdc42-dependent filopodia formation, providing a novel insight for therapeutic strategies in TNBC treatment.

Experimental study for visualizing CO2-dissolved water plume migration under hydraulic gradient conditions and implication for field monitoring data

Investigating the possible direction of a CO2-dissolved water plume migration near the potential CO2 leakage area is a significant task because it helps estimate the spatial and temporal monitoring scale to detect the signal of released CO2 from the storage. Accordingly, the Korea CO2 Storage Environmental Management (K-COSEM) research center tried to develop an intensive monitoring system and applied it to the artificial CO2 release test in the actual field. Monitoring data from the field tests depicted the horizontal movement of the CO2-dissolved water plume along the direction of the groundwater flow. However, it remains unclear how the CO2-dissolved water plume migrates vertically and how gas accumulation occurs near the capillary zone. The present study simulated the CO2 release test with a visual expression method utilizing a Hele-Shaw cell with hydraulic gradient conditions (i = 0, 0.1, and 0.01) and tried to estimate the significant influences on a diffusive-advective transport of the dissolved gas plume with the shallow aquifer condition. The visualization experiment results were intuitively verified to determine whether the theoretical principles of action related to plume flow applied in this context. The results suggest that a CO2-dissolved water plume is distributed by hydraulic gradients and density-driven CO2 convective flow. The plume shape, center, and area were analyzed using an image analyzer program; the results demonstrated that the plume characteristic evolved depending on the significant effects on the plume. When the plume was mainly affected by the hydraulic gradient, it rapidly moved from the injection point to the last boundary; in contrast, when it was influenced primarily by density-driven CO2 convective flow, it flowed diagonally downward in the shape of varied branches. The numerical model calculated the migration of the CO2-dissolved water plume affected by both factors. The laboratory experiment and numerical simulation results suggest that the migration of a CO2-dissolved water plume may be affected by the hydraulic gradient and density-driven CO2 convective transport. As such, these factors should be considered when designing and analyzing CO2 monitoring signals to detect CO2 leaks from shallow aquifer systems.

Collective behaviors of animal groups may stem from visual lateralization—Tending to obtain information through one eye

Collective behaviors of animal groups may stem from visual lateralization—Tending to obtain information through one eye