Transport Factors Research Articles

Computational Fluid Dynamics Modeling of Material Transport Through Triply Periodic Minimal Surface Scaffolds for Bone Tissue Engineering.

Cell-laden, scaffold-based tissue engineering methods have been successfully utilized for the treatment of bone fractures and diseases, caused by factors such as trauma, tumors, congenital anomalies, and aging. In such methods, the rate of scaffold biodegradation, transport of nutrients and growth factors, as well as removal of cell metabolic wastes at the site of injury are critical fluid-dynamics factors, affecting cell proliferation and ultimately tissue regeneration. Therefore, there is a critical need to identify the underlying material transport mechanisms and factors associated with cell-seeded, scaffold-based bone tissue engineering. The overarching goal of this study is to contribute to patient-specific, clinical treatment of bone pathology. The overall objective of the work is to establish computational fluid dynamics (CFD) models: (i) to identify the consequential mechanisms behind internal and external material transport through/over porous bone scaffolds designed based on the principles of triply periodic minimal surfaces (TPMS) and (ii) to identify TPMS designs with optimal geometry and flow characteristics for the treatment of bone fractures in clinical practice. In this study, advanced CFD models were established based on ten TPMS scaffold designs for (i) single-unit internal flow analysis, (ii) single-unit external flow analysis, and (iii) cubic, full-scaffold external flow analysis, where the geometry of each design was parametrically created. The influence of several design parameters, such as surface representation iteration, wall thickness, and pore size on geometry accuracy as well as computation time, was investigated in order to obtain computationally efficient and accurate CFD models. The fluid properties (such as density and dynamic viscosity) as well as the boundary conditions (such as no-slip condition, inlet flow velocity, and pressure outlet) of the CFD models were set based on clinical/research values reported in the literature, according to the fundamentals of internal and external Newtonian flow modeling. The main fluid characteristics influential in bone regeneration, including flow velocity, flow pressure, and wall shear stress (WSS), were analyzed to observe material transport internally through and externally over the TPMS scaffold designs. Regarding the single-unit internal flow analysis, it was observed that P.W. Hybrid and Neovius designs had the highest level of not only flow pressure but also WSS. This can be attributed to their relatively flat surfaces when compared to the rest of the TPMS designs. Schwarz primitive (P) appeared to have the lowest level of flow pressure and WSS (desirable for development of bone tissues) due to its relatively open channels allowing for more effortless fluid transport. An analysis of streamline velocity exhibited an increase in velocity togther with a depiction of potential turbulent motion along the curved sections of the TPMS designs. Regarding the single-unit external flow analysis, it was observed that Neovius and Diamond yielded the highest level of flow pressure and WSS, respectively, while Schwarz primitive (P) similarly had a relatively low level of flow pressure and WSS suitable for bone regeneration. Besides, pressure buildup was observed within the inner channels of almost all the TPMS designs due to flow resistance and the intrinsic interaction between the fluid flow and the scaffold walls. Regarding the cubic (full-scaffold) external flow analysis, the Diamond and Schwarz gyroid (G) designs appeared to have a relatively high level of both flow pressure and WSS, while Schwarz primitive (P) similarly yielded a low level of flow pressure and WSS. Overall, the outcomes of this study pave the way for optimal design and fabrication of complex, bone-like tissues with desired material transport properties for cell-laden, scaffold-based treatment of bone fractures.

Boron's Role in Diminishing Cadmium Concentrations in Rice (Oryza sativa L.): Insights into Absorption Inhibition and Ripening Promotion.

Boron, a crucial element for plant growth, has been demonstrated to mitigate cadmium (Cd) absorption in rice seedlings. However, its impact on Cd accumulation in rice grains and the underlying regulatory mechanisms remain poorly understood. The current study explored the roles of boron in reducing Cd accumulation and promoting ripening in rice through pot and hydroponic experiments. The results revealed that the basal boron application (1.5 mg kg-1) decreased grain Cd concentration by 61.1%, primarily due to the synergistic effects of inhibited Cd uptake and transport, along with increased maturation. Boron mitigated the root Cd2+ influx by 32.4% and transport factors by 36.0-47.3% primarily by downregulating the expression of OsNramp5, OsIRT1, and OsHMA2. Moreover, boron enhanced the activities of key sucrose-metabolizing enzymes and increased the relative expression levels of genes associated with sugar metabolism and transport, thereby shortening the rice growth period from 132 to 120 d. Field experiment confirmed that boron application decreased rice grain Cd concentration by 47.7% while promoting earlier maturation. This study elucidates the mechanism behind boron's ability to lower grain Cd levels and highlights its potential as an effective agronomic approach to mitigate food safety risks in rice grown on Cd-contaminated paddy soils.

Cryogenic Suction-A Major Salt Scaling Mechanism in Highway Concrete

Combined salt and frost attack is a major durability problem in concrete highway pavements in the state of Michigan, USA, where road-salts are used extensively for ice melting purposes. Previous studies have shown that continuous measurement of length-change during a freeze-thaw cycle is an effective tool in indentifying frost mechanisms. In this study the focus was to evaluate the cryogenic suction effect on frost expansion. The net frost expansion (linear dilation) was determined by monitoring the change in length of air-entrained concrete specimens undergoing a freeze-thaw cycle between 20 °C and -20 °C. Two dilation processes were found during freezing, an initial dilation at the freezing point (independent of surface exposure liquid), and a subsequent dilation, which is only found when a salt solution is present on the surface. Specimen expansion continues during the entire freezing period, including a 3 hour ramp at constant temperature (-20 °C). This secondary dilation dominates when the surface is exposed to a deicer solution. At constant temperature below initial freezing point, cryogenic suction of surface liquid (i.e., 3% salt solution) was found to be a major factor in sub-zero liquid transport that causes frost expansion in concrete. During this process, air voids are being filled as well and air is being displaced. Some air near the surface can escape. This was observed at -20 °C where escaping air was trapped in the liquid surface layer.

Prediction of heavy metal contamination in soil-groundwater systems at contaminated sites

ABSTRACT The diffusion of heavy metal pollutants in polluted industrial areas can cause severe environmental pollution in surrounding areas. However, the migration of pollutants into groundwater is a complex process that requires consideration of local geological and hydrological conditions, solute transport, and geochemistry factors to better predict the flow paths and plume dispersion of pollutants. This study is based on numerical models of Darcy's law and the Richards equation. A numerical model is used to predict the pollution risk of a certain abandoned metallurgical site. The results indicate that the risk of heavy metal leaching is extremely high under natural conditions, potentially affecting downstream reservoirs after 1500 days. The use of permeable reactive barriers (PRBs) can effectively prevent the migration of heavy metals. However, even with PRBs, 28%–30% of pollutants may still continue to spread outward through lateral flow pathways. The use of impermeable Funnel-and-gate PRB design can effectively reduce lateral pollutant migration, reducing lateral leakage by up to 27%. Based on these results, the rational design of PRBs can effectively reduce remediation costs and time, enhance groundwater remediation effectiveness, and provide strong support for environmental protection and ecological health.

Direct binding of arsenicals to nuclear transport factors disrupts nucleocytoplasmic transport.

Human exposure to arsenicals is associated with devastating diseases such as cancer and neurodegeneration. At the same time, arsenic-based drugs are used as therapeutic agents. The ability of arsenic to directly bind to proteins is correlated with its toxic and therapeutic effects highlighting the importance of elucidating arsenic-protein interactions. In this study, we took a proteomic approach and identified 174 proteins that bind to arsenic in Saccharomyces cerevisiae. Proteins involved in nucleocytoplasmic transport were markedly enriched among the arsenic-binding proteins, and we demonstrate that arsenic-binding to nuclear import factors results in their relocation from the nuclear envelope and subsequent aggregation in the cytosol. Similarly, nuclear pore proteins that make up the nuclear pore complex mislocalized and aggregated in arsenic-exposed cells. Consequently, arsenic was shown to inhibit nuclear protein import and export. We propose a model in which arsenic-binding to nuclear transport factors leads to their mislocalization and aggregation, which disrupts nucleocytoplasmic transport and causes arsenic sensitivity.

NtLPA1 overexpression regulates the growth of tobacco and enhances resistance to blight.

The involvement of Loose Plant Architecture 1 (LPA1) in regulating plant growth and leaf angle has been previously demonstrated. However, the fundamental genetic background remains unidentified. To further understand the tissue expression profile of the NtLPA1 gene, an overexpression vector (pBI121-NtLPA1) was developed and employed to modify tobacco using the leaf disc method genetically. Validation confirmed the generation of transgenic tobacco plants with NtLPA1 overexpression. The findings indicated that increased NtLPA1 overexpression substantially decreased plant auxin sensitivity and modulated signal transduction and polar transport, significantly reducing leaf angle, diminished leaf area during early and late growth stages, and shortened root length. In summary, NtLPA1 augmented tobacco resistance to severe shin disease by modulating the expression of disease-associated genes PBZ1, PR1b, and the growth regulator auxin polar transport factor PIN1.

Transport of lithium droplets between two nonparallel iron plates: A molecular dynamics study

The use of bionic structures for the efficient and passive directional transportation of liquid droplets is crucial in numerous industrial applications. Compared with conventional fluids, liquid metals are stable under a wide range of environmental conditions owing to their excellent physicochemical properties. However, the directional transportation of liquid metals remains challenging. Herein, inspired by the pecking feeding mode of shorebirds, we performed a series of systematic molecular dynamics simulations to study the directional transport of liquid lithium (Li) between non-parallel iron (Fe) plates. The simulations demonstrate that cyclically closing and opening the Fe plates induces the movement of Li droplets toward the tip of the beak-shaped plate. Increasing the opening angle and applying a positive strain of the Fe plates can increase the transport velocity of the Li droplets. Nevertheless, the dissolution of Fe atoms in the liquid Li due to corrosion hinders the transportation of Li droplet across the Fe plate. We simulated the impact of two surface nanostructures on Li transport behavior and found that saw-tooth nanostructures decrease transport efficiency and lead to droplet breakup, whereas nanogrooves improve transport capacity by promoting the capillary effect. This work indicates that understanding the mechanism and influencing factors of liquid Li transport between non-parallel plates is essential for the design of bionic structures for the efficient transport of liquid metals.

Current status of nano-embedded growth factors and stem cells delivery to bone for targeted repair and regeneration.

Stem cell transport and growth factors encapsulated in nanoparticles are becoming revolutionary methods for bone regeneration and repair. By encouraging stem cells to develop into osteoblasts, osteoinductive GFs like BMP-2, VEGF, and TGF-β can be delivered under control due to nanomaterials like nanoparticles, nanofibers, and nanotubes. By ensuring sustained release, these nanocarriers lessen adverse effects and enhance therapeutic results. In order to prove their survival and development, MCSs, which are essential for bone regeneration, are mixed with nanoparticles, frequently using scaffolds that resemble the ECM of bone. Furthermore, by adjusting to the injured environment and lowering inflammation, immunomodulatory nanostructures and stimuli-responsive nanomaterials can further maximize. While there are still shotcomings to overcome, including managing expenses, negotiating regulatory processes, and guaranteeing long-term safety, this method promises to outperform traditional bone grafting by providing quicker, more individualized, and more efficient treatments. Nano-embedded growth factors and stem cell technologies have the potential to revolutionize orthopedic therapy and significantly enhance patient outcomes with further research.

Sentiment Analysis of UINSU Students' Comfort Towards Trans Metro Deli Services at Taman Budaya Bus Stop Using the Naive Bayes Method

The large number of bus passengers at the Taman Budaya bus stop is one of the public transportation problems. Finding that the Metro Deli Bus Organizer is still operating. They are considered capable of meeting the requirements for choosing a mode of transportation. The purpose of this study is to determine the passenger transportation factors on the Trans Metro Deli Bus. The Trans Metro Deli Bus Passenger Transportation Factor is the purpose of this study. Data Collection Techniques Using Questionnaires Student comfort factors when using the Trans Metro Deli bus service. This study's methodology starts with problem identification and moves on to problem-solving techniques and assessment procedures. Respondents were given a questionnaire to fill out to collect data. The author of this study used Google Forms. The author of this study solved the problem using the Naïve Bayes algorithm. The Naïve Bayes algorithm model produces results with an accuracy of up to 71.43%, which is quite good. The accuracy results of 71.43% and approaching 100% show how accurate the sentiment analysis is using the Naïve Bayes classification. The accuracy results of 71.43% and approaching 100% show how accurate the sentiment analysis is using the Naïve Bayes classification. 'The bus took a long time to arrive' and 'didn't get a seat' were the most common negative reviews, indicating that some students felt uncomfortable. The Naïve Bayes results of the study showed that people who reviewed the Trans Metro Deli Bus expressed more positive opinions, with the highest score of 71.43%.

Process analysis of elevated concentrations of organic acids at Whiteface Mountain, New York

Abstract. Organic acids represent an important class of compounds in the atmosphere, but there is limited research investigating their chemical production, particularly in the northeast United States. To improve our understanding of organic acid sources, a modeling analysis was performed for air masses reaching the summit of Whiteface Mountain (WFM), New York, where measurements of organic acids in cloud water have been collected. The analysis focuses on a pollution event associated with a heat wave that occurred on 1–2 July 2018 that exhibited unusually high concentrations of formic (HCOOH), acetic (CH3COOH), and oxalic (OxAc) acid in cloud water. The gas-phase production of organic acids for this pollution event was modeled using a combination of the regional transport model Weather Research and Forecasting Model with Chemistry (WRF-Chem), which gives information on transport and environmental factors affecting air parcels reaching WFM, and the Lagrangian chemical box model BOXMOX, which allows analysis of chemistry with different chemical mechanisms. Two chemical mechanisms are used in BOXMOX: (1) the Model for Ozone and Related chemical Tracers (MOZART T1) and (2) the Master Chemical Mechanism (MCM) version 3.3.1. The WRF-Chem results show that air parcels sampled during the pollution event at WFM originated in central Missouri, which has strong biogenic emissions of isoprene. Many air parcels were influenced by emissions of nitrogen oxides (NOx) from the Chicago metropolitan area. The gas-phase oxidation of isoprene and its related oxidation products was the major source of HCOOH and CH3COOH, but both mechanisms substantially underproduced both acids compared to observations. A simple gas–aqueous mechanism was included to investigate the role of aqueous chemistry in organic acid production. Aqueous chemistry did not produce more HCOOH or CH3COOH, suggesting missing chemical sources of both acids. However this aqueous chemistry was able to explain the elevated concentrations of OxAc. Anthropogenic NOx emissions from Chicago had little overall impact on the production of all three organic acids. Further studies are required to better constrain gas and aqueous production of low-molecular-weight organic acids.

Enhanced efficiency of the electrode by doping of neodymium on SmFeO3 for the application of supercapacitor

In response to growing demand for the renewable energy generating and storage systems, scientists are trying to synthesized electrode material with exceptional performance. Their primary objective was to develop portable intelligent technology gadgets that could guarantee global energy security. In the reported article, the SmFeO3 with Nd-doped material was manufactured by cost-effective hydrothermal method for the application of a supercapacitor. The results demonstrate that the existence of larger surface area improves electrical conduction and improves the electrons and ions pathway, resulting in a rapid charge storage device and greatly enhancing the electrical performance. The pristine SmFeO3 electrode achieved capacitance of 746.3 F g−1, and the Nd-doped SmFeO3 electrode achieved a heightened capacitance of 1455.9 F g−1 at 1 A g−1. Further, the pristine SmFeO3 electrode demonstrated low cyclic retention after the 5000th charging/discharging cycles, while the Nd-doped SmFeO3 electrode demonstrated significant cyclic retention. In addition, the material fabricated attained a significant capacitance of 923.9 F g−1 at 10 mV s−1 during cyclic voltammetry measurements. The exceptional performance of dopant materials suggests their promising conductivity and quick electron/ion transport factors in its exceptional performance made it an excellent electrode for energy storage devices as well as suitability for future-generation energy conversion by surpassing the reliance on perovskite-type structural materials.

Transport of particulate mercury along the reservoir- downstream - estuary continuum during the water-sediment regulation scheme period of Yellow River in 2018.

As an important link of mercury (Hg) migration and transformation from land to ocean, rivers have been significantly influenced by anthropogenic activities, resulting in unpredictable environmental influences on the basin and offshore areas. In this study, the particulate Hg content of sediments in Xiaolangdi Reservoir (XLDR), Lijin Hydrological Station, and the Yellow River estuarine area during the water-sediment regulation scheme (WSRS) period in 2018 were analyzed, the characteristics and influencing factors of particulate Hg transport were explored. Our results revealed that the transport flux of particulate Hg into the sea during WSRS was 8.7 t, accounting for 68.8 % of the annual flux. High Hg content derived from the anthropogenic sources was observed in XLDR sediment, and Hg content in sediments of the lower reaches and estuary was elevated due to the sediments were mainly from XLDR during the sediment regulation stage. Under the influence of WSRS, the Hg content in the sediments of the lower reaches to estuary continuum was affected by the variation of sediment particle size, which was caused by the difference of sediment sources. In addition, WSRS led to a change in the binding forms of Hg in sediments, from mostly binding with organic matter in the XLDR to being comprehensively restricted by organic matter, iron and manganese oxides and carbonate minerals. Therefore, the transport behaviors and deposition patterns of particulate Hg in the reservoir-downstream-estuarine continuum has a good response to the implementation process of WSRS.

Analysis of Transport Accessibility and Factors Influencing The Competitiveness of The Ports of Świnoujście and Gdynia

This study deals with the transport accessibility of the main ports in Poland, which affect the state of the national economy in the statutory sense. The seaports: Świnoujście and Gdynia, acting as the main communication hubs in multimodal transport, are at the same time an important element in global supply chains – they are also strategic points for transshipment of goods and passenger service, combining various branches of transport, including sea, land and rail. The article presents a comparative analysis of the seaports in Świnoujście and Gdynia, focusing on their transport accessibility and competitiveness in the logistics market. Key aspects, such as the length of the quay, the number of ships served and the volume of container transshipment, are taken into account to ensure a comprehensive result of each port in the context of operational attractiveness. There are many examples of presenting transport accessibility in the literature on the subject, and many examples are also contained in the literature on the ports themselves. However, in the study, the research was focused on a comparative analysis of the ports themselves as poles in opposing markets in geographical terms.

Dual influence of protonation on Li-ion transport in garnet solid electrolytes: A first-principles study

Garnet-type cubic Al-doped Li7La3Zr2O12 (LLZO) is a promising solid electrolyte for all-solid-state Li-ion batteries because of its excellent ionic conductivity and stability against Li metal. However, its sensitivity against moisture poses a significant challenge, as LLZO undergoes protonation upon exposure to water, which has been experimentally observed to reduce Li-ion conductivity. Despite this, the exact impact of protonation-induced structural changes and the role of protons in Li-ion transport within LLZO remain unclear. A thorough understanding of these mechanisms is crucial for enhancing the performance of LLZO as a solid electrolyte. In this study, we employed density functional theory (DFT) and DFT-based molecular dynamics (DFT-MD) simulations to investigate the effect of protonation on the structure, Li-ion transport, and proton dynamics in LLZO. Our results demonstrate that protonation induces a phase transition from the centrosymmetric Ia3‾d to a distorted non-centrosymmetric I4‾3d symmetry, concomitantly reducing the Li-ion conductivity, consistent with experimental observations. Furthermore, we identify two competing effects of protonation on Li-ion transport: protons tend to occupy octahedral sites, which trap Li-ions in more stable tetrahedral sites, thereby impeding their mobility. Conversely, proton insertion enlarges the bottlenecks along Li-ion diffusion pathways from a range of 1.78–1.90 Å to 1.80–1.92 Å, potentially lowering the diffusion barrier for Li transport. Therefore, protonation introduces both inhibitory and facilitating factors for Li-ion transport. Additionally, the reduction in Li-ion concentration due to protonation further diminishes the overall ionic conductivity of LLZO.

Differential expression profile of miRNAs in maternal amniotic fluid exosomes in fetuses with isolated ventriculomegaly

To investigate the role of miRNAs in maternal amniotic fluid exosomes in development of isolated ventriculomegaly (VM) in fetuses. Amniotic fluid samples were collected from 9 cases of moderate isolated VM and 8 normal control cases to extract exosomal miRNA, and miRNA sequencing technique was used to identify differentially expressed miRNAs between the two groups. Three miRNAs with significant differential expression between the two groups, whose high expression was associated with VM, were selected for verification with RT-qPCR. Dual luciferase reporter assays were used to verify the regulatory effect of miR-122-5p on its predicted target genes AKT3 and CCDC88C. Gene ontology (GO) and KEGG pathway analyses were performed to explore the possible roles of the top 40 significant differential miRNAs in the pathophysiology of VM. We identified a total of 272 differentially expressed miRNAs in VM cases, including 43 up-regulated and 229 down-regulated miRNAs. The target genes of these differential miRNAs were associated with DNA and transcription factor binding, transmembrane transporter and nucleic acid binding transcription factor activity, and cell developmental process. These miRNAs were mostly enriched in the MAPK, cGMP-PKG and Wnt signaling pathways. Verification with RT-qPCR showed that miR-122-5p expression level was significantly lower in VM group than in the control group (P < 0.05), which was consistent with miRNA sequencing results; let-7b-5p expression level was significantly lower in VM group, which was contrary to miRNA sequencing result. Dual luciferase reporter assays showed that miR-122-5p was not capable of regulating AKT3 or CCDC88C expressions. The highly abundant differentially expressed miRNAs in maternal amniotic fluid exosomes play important roles in the occurrence of fetal VM possibly by regulating the MAPK, PI3K-Akt, Wnt and cGMP-PKG signaling pathways.

Multiplexed perturbation of yew reveals cryptic proteins that enable a total biosynthesis of baccatin III and Taxol precursors.

Plants make complex and potent therapeutic molecules, but difficulties in sourcing from natural producers or chemical synthesis can challenge their use in the clinic. A prominent example is the anti-cancer therapeutic paclitaxel (Taxol®). Identification of the full paclitaxel biosynthetic pathway would enable heterologous drug production, but it has eluded discovery despite a half century of intensive research. Within the search space of Taxus' large, enzyme-rich genome, we suspected the complex paclitaxel pathway would be difficult to resolve using conventional gene co-expression analysis and small sample sets. To improve the resolution of gene set identification, we developed a multiplexed perturbation strategy to transcriptionally profile cell states spanning tissues, cell types, developmental stages, and elicitation conditions. This approach revealed a set of paclitaxel biosynthetic genes that segregate into expression modules that suggest consecutive biosynthetic sub-pathways. These modules resolved seven new genes that, when combined with previously known enzymes, are sufficient for the de novo biosynthesis and isolation of baccatin III, an industrial precursor for Taxol, in Nicotiana benthamiana leaves at levels comparable to the natural abundance in Taxus needles. Included are taxane 1β-hydroxylase (T1βH), taxane 9α-hydroxylase (T9αH), taxane 7β-O-acyltransferase (T7AT), taxane 7β-O-deacetylase (T7dA), taxane 9α-O-deacetylase (T9dA), and taxane 9-oxidase (T9ox). Importantly, the T9αH we discovered is distinct and independently evolved from those recently reported, which failed to yield baccatin III with downstream enzymes. Unexpectedly, we also found a nuclear transport factor 2 (NTF2)-like protein (FoTO1) crucial for high yields of taxanes; this gene promotes the formation of the desired product during the first taxane oxidation step, resolving a longstanding bottleneck in paclitaxel pathway reconstitution. Together with a new β-phenylalanine-CoA-ligase, the eight genes discovered in this study enables the complete reconstitution of 3'-N-debenzoyl-2'-deoxy-paclitaxel with a 20-enzyme pathway in Nicotiana plants. More broadly, we establish a generalizable approach for pathway discovery that scales the power of co-expression studies to match the complexity of specialized metabolism, enabling discovery of gene sets responsible for high-value biological functions.

Analysis of Decoupling Effects and Influence Factors in Transportation: Evidence from Guangdong Province, China

In recent years, global environmental issues have become increasingly prominent. The transportation industry, as the fundamental sector of national economic development, is also characterized by high energy consumption and carbon emissions. Therefore, it is imperative to conduct research on the carbon emission problem within this industry. In light of the Tapio decoupling model, an analysis of the correlation between traffic carbon emissions and economic development in Guangdong province during 1999–2019 was carried out. With the aim of encouraging Guangdong province’s low-carbon transportation development, the factors affecting the transportation industry are analyzed utilizing the generalized Divisia index model (GDIM). We also introduced passenger and freight turnover as an influencing factor for analysis. The findings indicate that (1) Guangdong province’s traffic carbon emissions increased from 1999 to 2019; (2) the traffic carbon emissions’ decoupling effect is mainly “weakly decoupled”, and the overall decoupling effect is not strong in Guangdong province; (3) among the traffic carbon emissions’ factors, the effects of the production value of traffic and the turnover volume are at the forefront, and the effect of turnover volume has gradually exceeded the production value of traffic in recent years. The suppression of the intensity of carbon emissions is relatively large, while the suppression of the intensity of energy consumption and transport is relatively weak. Based on this, strategies were proposed to promote a cleaner energy mix, improve energy use efficiency, create energy savings, develop green technologies, and foster the restructuring of transportation.

Plastic transport in rivers: Bridging the gap between surface and water column

Rivers act as an important transportation pathway for land-based plastic litter to the ocean. Recently, rivers have also been identified as potential sinks and reservoirs for plastics. Knowledge of plastic transport over different depth profiles in rivers remains limited. In this study, we evaluated the vertical distribution of macro- and mesoplastics, using a larvae net and a trawl net in the river Rhine and its two major branches, i.e. Waal and IJssel. Subsequently, to estimate the relationship between the surface transport of plastic items, i.e., floating items, compared to the transport in deeper layers in the water column, including suspended and bed-transported plastic, an extrapolation factor was derived per day for the middle and bottom nets divided by those found in the surface net. The observed macro- and mesoplastic OSPAR categories collected in different layers in the water column were rather consistent between different sampling techniques. Fragments of soft mesoplastic falling under the category “Plastic film plastics 0–2.5 cm (soft)" were recorded most frequently in the investigated rivers with our monitoring techniques. During larvae net monitoring, hard plastics were more frequently found at the river surface than at the middle or bottom of the river for both macroplastic and mesoplastics, while soft plastics were more frequently detected near the bottom. For larvae net monitoring, the extrapolation factor, reflecting the concentration ratio of macroplastic items transport at different depths, i.e., from the surface downwards to the middle and the bottom ranged between 0.38 to 2.2 and 0.36 to 5.7, respectively. The extrapolation factor of mesoplastic transport from the surface downwards to the middle and the bottom ranged between 0.70 to 1.84 and 0.69 to 2.57. During trawl net monitoring, the extrapolation factor, reflecting the concentration ratio, for macroplastic ranged between 0.82 and 1.30, and for mesoplastic between 0.52 and 1.40. Overall, the findings of this study show that estimates of plastic concentrations solely based on surface transport could result in an under- or overestimation of riverine plastic transport.

To ride-hail or not to ride-hail? Complementarity and competition between public transit and transportation network companies through the lens of app data

AbstractTransportation Network Company (TNC) services have become a prominent factor in urban transportation in recent years, and there is an ongoing debate regarding their relationship with public transit. While many argue that TNCs draw passengers away from public transportation, others believe the two modes complement each other. However, due to the inadequate sample size of rider surveys as primary data sources, our understanding of how riders choose between these two modalities remains limited. This study uses nine months of trip planning data generated by the Transit App, which captures how travelers engage with multiple options in real time, including TNC and public transit services. We extract measures from Transit describing the travel options and the habits of each individual user for sessions in which the user “tapped” on one of these two modes, indicating consideration of it as an option. Machine learning models predict the likelihood of a rider tapping TNC based on features of the available public transit options and other contextual factors (e.g., time of day, weather conditions). The models find that these taps are driven by factors that highlight the convenience of TNC, such as the waiting time, walking distance, and the number of transfers for public transportation trips. We also find that the majority of TNC trips tapped by app users combine the two modes when using the Transit App, with TNC acting as a connection to or from public transit. These results provide detailed additional evidence for current arguments for both competition and complementarity between TNC and public transit from a population that uses an app to navigate public transit.

Examining the Impact of the Built Environment on Multidimensional Urban Vitality: Using Milk Tea Shops and Coffee Shops as New Indicators of Urban Vitality

Urban vitality is a critical driver of sustainable urban development, significantly contributing to the enhancement of human well-being. A thorough and multidimensional comprehension of urban vitality is essential for shaping future urban planning and policy-making. This study, focused on Chengdu, proposes a framework for assessing various dimensions of UV through the distribution of milk tea and coffee shops. Using random forest and multi-scale geographically weighted regression models, this study investigates the factors influencing urban vitality from both mathematical thresholds and spatial heterogeneity, and develops spatial maps of future vitality to inform targeted urban strategies. The results show that (1) the milk tea index is effective in capturing population vitality, while the coffee index is more closely associated with economic vitality and urban renewal; (2) office buildings (13.46%) and commercial complexes (13.70%) have the most significant impact on both economic and population vitality, while the importance of transportation factors has notably decreased; (3) the influence of these factors demonstrates spatial heterogeneity and nonlinear relationships, with subway station density of 0.5–0.8 stations per kilometer being optimal for stimulating both types of vitality. The minimum threshold for economic vitality in a given unit is a housing price exceeding 6000 RMB/m2; (4) the future vitality map suggests that urban planners should pay greater attention to non-central districts with high development potential. Moreover, spontaneous social interactions and consumer behaviors stimulated by various shops are critical components of urban vitality. In designing the physical environment and urban spatial forms, special attention should be given to enhancing the attractiveness of physical spaces and their capacity to accommodate social interaction.