Transport Processes Research Articles

NaCl aerosol filtration over filter media with intrafiber porosity: can filtrate capacity be increased by wicking into this pore volume?

This paper investigates a novel fiber-based filter media wherein a NaCl filtrate is collected and reservoired not only onto the surfaces of the fibers and within their inter-fiber voidage but also within the internal porosity of high pore volume nanoporous fibers or vapor grown carbon nanofibers (VGCF) floc used to fabricate the media. This transport process is shown to occur through a NaCl dissolution into the water-filled nanopores of the fiber and a subsequent intra-fiber wicking phenomenon. The study further elucidates two distinct NaCl accommodation mechanisms which are uniquely available to filter media containing nanoporous intrafiber porosity: (1) wicking and capillary condensation of liquid NaCl aerosols directly into the intrafiber pores at high RH, and (2) dissolution of otherwise solid NaCl aerosols deposited onto fiber surfaces (at low RH) into the interior nanopores of the fiber because these pores (when hydrophilic) are saturated with water (even at low RH). To investigate these two mechanistic regimes, various media were fabricated possessing multiscale porosity in the form of: (i) embedded flocs of VGCFs (4.108 cm3gm-1pore volume), (ii) hydrophilic and high pore volume activated carbon fibers (ACFs, 0.950 cm3gm-1) and (iii) solid graphite fibers. These media were then comparatively evaluated toward NaCl aerosol filtration at different relative humidities. Pressure drop measurements versus filtrate accumulation and SEM-EDAX VGCF demonstrated the location and transport of NaCl into the intrafiber voidage. Media containing both VGCF floc and ACF accumulated 1200% more NaCl at low RH (and a specified pressure drop) than similar media prepared from non-porous graphite fibers, with an additional 315% increase from low to high RH. A Gibbs free energy driving force model is provided to illustrate the driving forces favoring water condensation into the nanopores and solid NaCl aerosol dissolution into the water phase. Filtration efficiency and quality factor assessments for the various media are also systematically evaluated to demonstrate the observed mechanistics.

Arabidopsis hydathodes are sites of auxin accumulation and nutrient scavenging.

Hydathodes are small organs found on the leaf margins of vascular plants which release excess xylem sap through a process called guttation. While previous studies have hinted at additional functions of hydathode in metabolite transport or auxin metabolism, experimental support is limited. We conducted comprehensive transcriptomic, metabolomic and physiological analyses of mature Arabidopsis hydathodes. This study identified 1460 genes differentially expressed in hydathodes compared to leaf blades, indicating higher expression of most genes associated with auxin metabolism, metabolite transport, stress response, DNA, RNA or microRNA processes, plant cell wall dynamics and wax metabolism. Notably, we observed differential expression of genes encoding auxin-related transcriptional regulators, biosynthetic processes, transport and vacuolar storage supported by the measured accumulation of free and conjugated auxin in hydathodes. We also showed that 78% of the total content of 52 xylem metabolites was removed from guttation fluid at hydathodes. We demonstrate that NRT2.1 and PHT1;4 transporters capture nitrate and inorganic phosphate in guttation fluid, respectively, thus limiting the loss of nutrients during this process. Our transcriptomic and metabolomic analyses unveil an organ with its specific physiological and biological identity.

Investing in technology to address labour shortages in UK fresh produce and horticulture: How does this redefine standards of good agricultural practice

The global agri-food sector is becoming more fragile as a result of supply chain shocks like COVID-19, Brexit and conflict, which is posing a growing challenge to the horticultural industry. As a result, it is becoming clearer how crucial seasonal agricultural migrant workers are to ensuring food security. Delivering GAP requires taking into account the effects of COVID-19 and Brexit on the UK’s fresh produce and horticulture sectors as well as the potential for increased demand for automation and Agriculture 4.0. In the medium and long run, the market conditions may favourably accelerate automation and the adoption of Agriculture 4.0 as a workable solution to the workforce shortage. The greatest opportunities for automation and the application of new technology will be found in the transport, harvest, and post-harvest processes. Investment in automation and technology adoption depends on access to finance, appropriate training and upskilling, and other stakeholders’ support (e.g. by retailers). We conclude that understanding the need for automation, embracing Agriculture 4.0, utilising labour schemes, and envisioning how work and farming will change in the future is critical when examining GAP in the context of an integrated approach within the fresh produce and horticulture sectors.

Generation of circular symmetric Airy vortex beams based on spin-multiplexed metasurface

Given that circular symmetric Airy vortex beam (CSAVB) was found to possess a stable central cavity and an opposing transport process to circular Airy vortex beam, it has been recognized as a potentially powerful tool for particle trapping and optical communication. In order to facilitate broader application scenarios, this paper presents a novel approach to the generation of multiple CASVBs based on a single metasurface. In the proposed method, three independent CSAVBs carrying different new kinds of power-exponent-phase vortices (NPEPVs) can be obtained under two orthogonal circularly polarized or an arbitrary linear polarized incident, respectively. Each of these vortex structures is characterized by a distinct orbital angular momentum, which is jointly determined by two parameters of the NPEPVs. This indicates that the CSAVB and the device have greater freedom than the canonical optical vortex beams and the previous vortex beam generators in controlling the optical vortex. These results have the potential to advance the development of vortex beams and enhance their applications in micromanipulation, optical communication and imaging.

An Approach of Integration of Contextual Data in E-Service System for Management of Multimodal Cargo Transportation

Our research area concerns the development of an intelligent e-service system to help manage multimodal transportation processes. To better respond to the requirements of sustainable development, we encourage the development of multimodal cargo transportation. Therefore, it is important to ensure that the dissemination and management of information in multimodal transportation requires more accurate information transmission and implementation for better coordination of these processes with the interaction of all process participants. Also, contextual data integration into the e-service provision processes is important for more adequate real cargo transportation management. The transition to multimodal freight transport and the increase in its activity directly impact the sustainable development of this sector as transport flows are removed from ground roads and distributed more evenly to load more railways and sea vessels. This research aims to develop an approach to developing the infrastructure of an e-service system with the ability to integrate contextual data and influence the management of multimodal transportation. The methodological approach is based on methods of conceptual representation of information and methods for recognizing the flow of needful information during multimodal freight transportation according to adaptable management processes. The e-service provision system creates benefits for cargo drivers and delivery managers with more accurate information implementation and more adequate coordination of processes under real conditions by helping them make the right decisions.

Double modulation of the electric field in InGaAs/Si APD by groove rings for the achievement of THz gain-bandwidth product

Abstract Avalanche photodiode (APD) is commonly used as a receiver in optical communication and light detection and ranging (LIDAR), offering highly sensitive photodetection capabilities. A key strategy for improving the gain-bandwidth product (GBP) of the APD involves the optimization of the electric field distribution using the charge layer. However, traditional modulation methods to adjust the carrier transport and avalanche process using the charge layer often face challenges (inefficiency and non-uniformity). An InGaAs/Si APD based on the wafer bonding method with a GBP up to 1.03 terahertz (THz) is reported theoretically in this work. The charge layer and groove rings are inserted at the InGaAs/Si bonded interface to modulate the electric field in the APD effectively, demonstrating low dark current and reduced avalanche bias of the device. This approach induces a dramatic and rapid variation of the electric field at the interface while reducing the gradient of the electric field in the multiplication layer. Additionally, the indirect impact of the groove ring on mitigating the adverse effects of the lattice mismatch is pointed out, and the optimal doping concentration range of the charge layer is identified to enhance the modulation effect of the electric field for stronger impact ionization. These findings provide valuable insights for the next-generation InGaAs/Si APDs with high GBP for the high-speed data transmission.

Photo‐activation of Tolane‐based Synthetic Ion Channel for Transmembrane Chloride Transport

While natural channels respond to external stimuli to regulate ion concentration across cell membranes, creating a synthetic version remains challenging. Here, we present a photo‐responsive uncaging technique within an artificial ion channel system, which activates the ion transport process from a transport‐inactive o‐nitrobenzyl‐based caged system. From the comparative ion transport screening, 1b emerged as the most active transporter. Interestingly, its bis(o‐nitrobenzyl) derivative, i.e., protransporter 1b' was inefficient in transporting ions. Detailed transport studies indicated that compound 1b is an anion selective transporter with a prominent selectivity towards chloride ions by following the antiport mechanism. Compound 1b' did not form an ion channel, but after the o‐nitrobenzyl groups were photocleaved, it released 1b, forming a transmembrane ion channel. The channel exhibited an average diameter of 6.5 ± 0.2 Å and a permeability ratio of PCl‐⁄PK+ = 7.3 ± 1.5. The geometry‐optimization of protransporter 1b' indicated significant non‐planarity, corroborating its inefficient self‐assembly. In contrast, the crystal structure of 1b demonstrates strong self‐assembly via the formation of an intermolecular H‐bond. Geometry optimization studies revealed the plausible self‐assembled channel model and the interactions between the channel and chloride ion.

Photo-activation of Tolane-based Synthetic Ion Channel for Transmembrane Chloride Transport.

While natural channels respond to external stimuli to regulate ion concentration across cell membranes, creating a synthetic version remains challenging. Here, we present a photo-responsive uncaging technique within an artificial ion channel system, which activates the ion transport process from a transport-inactive o-nitrobenzyl-based caged system. From the comparative ion transport screening, 1b emerged as the most active transporter. Interestingly, its bis(o-nitrobenzyl) derivative, i.e., protransporter 1b' was inefficient in transporting ions. Detailed transport studies indicated that compound 1b is an anion selective transporter with a prominent selectivity towards chloride ions by following the antiport mechanism. Compound 1b' did not form an ion channel, but after the o-nitrobenzyl groups were photocleaved, it released 1b, forming a transmembrane ion channel. The channel exhibited an average diameter of 6.5 ± 0.2 Å and a permeability ratio of PCl-⁄PK+ = 7.3 ± 1.5. The geometry-optimization of protransporter 1b' indicated significant non-planarity, corroborating its inefficient self-assembly. In contrast, the crystal structure of 1b demonstrates strong self-assembly via the formation of an intermolecular H-bond. Geometry optimization studies revealed the plausible self-assembled channel model and the interactions between the channel and chloride ion.

Simulation and Analysis of Ozone Pollution Process in Shijiazhuang Based on CMAQ-ISAM Model

In Shijiazhuang City, ozone （O3） pollution occurs frequently in June every year. In June 2023, the average O3 8 h concentration （O3-8h） pollution exceeded 80% of the days in the month, and O3 was the primary pollutant, accounting for 100%. For an O3 heavy pollution process from June 11 to 18, the air quality model WRF-CMAQ was used for simulation, and the average error data MFB and MFE were -10.47% and 17.96%, respectively, which was within the ideal error range. The CMAQ process analysis module was used to simulate the physical and chemical processes in Shijiazhuang City, and the dry deposition （DDEP） contribution concentration was -23.88 μg·m-3, which was the main process of O3 consumption, whereas the transport process （TRAN） was the main source of O3, among which the contribution was more significant in vertical transport （VTRA）. At the same time, the source analysis module （ISAM） was used to analyze the O3 contribution of local and surrounding areas in Shijiazhuang City. The results showed that the contribution rate of local industry sources in Shijiazhuang City was as follows： traffic source （12.54%） > industrial source （6.94%） > residential source （6.56%） > power source （4.75%）. The long-distance transmission source （BCON） continued to be in the first place with a high contribution rate of 63.31%. In the heavy pollution period under stable weather, the contribution concentration of BCON in the D02 layer of the nested domain to Shijiazhuang City was lower than the sum of the marked area. Among the surrounding cities, Baoding City had the highest contribution rate under stable weather, accounting for 26.21%. In the late period, the contribution concentration of Xingtai City increased rapidly under the action of high-value southwest wind. To effectively reduce O3 pollution, it is necessary to reduce emissions in the city and to control the upwind cities in advance, and the implementation of inter-regional joint prevention and control is the key.

Effect of cap layer and post growth on-site hydride passivation on the surface and interface quality of InAsP/InP hetero and QW structures

The performance of devices made from III-V compound semiconductors relies heavily on their surface and interface properties. The InAsP/InP material system is recently gaining interest due to its suitability for the next generation of long-haul classical and quantum communication applications. Researchers are studying how surface and interface properties affect the efficiency of the device and concludes that the epitaxial growth conditions responsible for creating surface and interface states require further improvement. To address this, we have studied the effect of the top (cap) layer and post-growth on-site hydride passivation on the properties of InAsP/InP hetero-structures grown using metal-organic vapor phase epitaxy technique. The flow rate and flux ratios of the hydrides significantly affect the surface reaction rates and gas-phase diffusion coefficients, which in turn impact the As↔P exchange mechanisms. Our findings suggest that post-growth on-site arsine passivation encourages the As↔P substitutions at the vicinity of the desorption sites of phosphorus, leading to the arsenic-rich surface of InAsP with the diffused hetero-interfaces. The activation energy for such As↔P exchange reaction mechanism is evaluated as ∼ (1.4 ± 0.3) eV. On the other hand, it has been observed that the thin cap layer of InP protects the surface of the InAsP epilayer and thereby preserving the sharp interface. Further, surface photovoltage and photoluminescence spectroscopy is employed to examine the role of the diffused and sharp interface of InAsP/InP hetero-structures in charge carrier transport, their redistribution and recombination process. Our analysis of the energy transitions occurring in the surface photovoltage and photoluminescence spectrum reveal that the energy band alignment and the subsequent charge carrier redistribution processes is influenced by the surface and interface states. These changes in the surface photovoltage phase spectra of InAsP/InP system also support the role of surface and interface states in the generation and separation of the charge carriers. The study provides insights into the effects of As↔P exchange on surface and interfacial quality, highlighting the implications for optoelectronic device development using InAsP/InP material system.

Immunohistochemical parameters of serous ovarian carcinomas and possible mechanism of development of resistance to platinum-based drugs

The aim of the study was to evaluate a prognostic significance of immunohistochemical parameters in serous ovarian carcinomas and their statistical relationships after neoadjuvant treatment to assess the development of tumor resistance to platinum-containing adjuvant polychemotherapy regimens. Material and Methods. An immunohistochemical study of tumor tissue was carried out in patients with high-grade serous ovarian cancer (stage IIIC–IV). The age of the patients ranged from 49–72 years. There were 59 patients who were sensitive and 22 patients who were resistant to platinum-containing adjuvant polychemotherapy. In the tissue of ovarian tumors obtained during surgery after noadjuvant polychemotherapy, we studied immunohistochemical indicators of proliferative activity (Ki67), expression of the DNA excision repair protein ERCC1 and proteins of the ABC transporter family – Pgp and BCRP, as well as statistical relationships between these indicators (Spearman’s rank correlation coefficient). Results. After effective neoadjuvant polychemotherapy, more pronounced signs of activity in the processes of proliferation, DNA repair and xenobiotic efflux were noted in serous ovarian carcinomas, which subsequently demonstrated resistance to platinum-containing polychemotherapy regimens compared to tumors that retained platinum sensitivity. Moreover, in 40 % of cases or more, there was a coincidence in the ranges of values of the studied parameters in tumors with different sensitivity to platinum drugs. The expression of transporter proteins greater than 60 % for BCRP and 65 % for Pgp was shown to precede the development of resistance to adjuvant treatment with carboplatin. In the studied groups, differences in the number and significance of statistical relationships between the variables were observed. The most significant differences were noted for the Ki67 – BCRP correlation, which had the opposite direction in groups with different sensitivity to adjuvant treatment with carboplatin. Conclusion. A comprehensive immunohistochemical analysis of highgrade serous ovarian carcinomas after neoadjuvant polychemotherapy, which further demonstrated different sensitivity to platinum-containing adjuvant regimens, was carried out, and the prognostic value of the studied parameters was assessed. The revealed critical levels of Pgp and BCRP expression in tumor tissue may have a prognostic value regarding the effect of adjuvant polychemotherapy. The results of the correlation analysis suggest a relationship between the development of platinum resistance and changes in the nature of the regulatory relationships between proliferative activity and transport processes in tumor tissue.

Urine Sample Handling in Laboratory—Process Reengineering is the Need of the Hour

Background and Aims: Monitoring and a continual improvement of turnaround time (TAT) in urine examination and reporting is essential for improved management of laboratory quality as well as ensuring patient satisfaction. TAT can be impacted by multiple factors, some of which appear to be beyond the control of laboratory, especially the preanalytical phase of urine examination such as specimen collection, transportation and sample preparation. The aim of the study was to compare the preanalytical variables like TAT for transportation and incidences of spill between our current urinalysis workflow process and the new urinalysis workflow process using a pneumatic chute-compatible closed urine collection system. Materials and Methods: This observational prospective study was conducted on 4/9/23 from 9 am to 4 pm at the laboratory of Apollo Main Hospital, Chennai. Pneumatic chute compatible closed urine collection cup was given to the patients in Group-A and normal screw cap containers which we are currently using were given to the patients in Group-B. Once the urine samples were collected in the respective containers, they were transported to the laboratory using pneumatic chutes for Group-A samples and manual carry for Group-B samples. Analysis of transportation time using the new collection method (Group-A) when compared with the current method of practice (Group-B) was done. The incidence of spillage was also monitored. Results: A significant improvement was noticed in the transportation process and spill incidence with closed collection devices through the pneumatic chute. Conclusion: To conclude, the implementation of pneumatic chute compatible closed collection tubes for urine improves the transportation and processing time, eliminates the manual carry of urine samples, eliminates the incidences of leakage and spillage, reduces errors and reduces the exposure of urine to healthcare workers, thereby leading to significant improvement in patient care, patient experience and staff satisfaction.

Mechanisms of Proppant Transport in Rough Fractures of Offshore Unconventional Reservoirs: Shale and Tight Sandstone

After hydraulic fracturing, unconventional reservoirs frequently encounter challenges related to limited effective proppant support distance and suboptimal proppant placement. Due to the strong heterogeneity of offshore reservoirs, which causes varying fracture roughnesses depending on different lithologies, a systematic study of the relationship between roughness and proppant transport could optimize operational parameters. This study incorporates the box dimension method for fractal dimension analysis to quantify roughness in auto-correlated Gaussian distributed surfaces created by true triaxial tests. Combined with the numerical analysis of (computational fluid dynamics) CFD-DEM (discrete element method) for bidirectional coupling, the laws of proppant deposition and transport processes within fractures with different roughnesses are obtained through comparative verification simulations. The results show that for rougher fractures of shale, the proppants are transported farther, but at JRC_52, (joint roughness coefficient), where there may be plugging in curved areas, there is a risk of near-well blockages. Compared to the smooth model, fluctuations in JRC_28 (tight sandstone) drastically increase turbulent kinetic energy within the fracture, altering particle transport dynamics. Moreover, smaller proppants (d/w ≤ 0.3) exhibit better transport capacity due to gravity, but the conductivity of the proppant is limited when the particles are too small. A d/w of 0.4 is recommended to guarantee transport capacity and proppant efficiency near the well. Additionally, proppants injected sequentially from small to large in shale fractures offer optimal propping effects, and can take advantage of the better transport capacity of smaller proppants in rough fractures. The large proppant (d/w = 0.8) is primarily deposited by gravity and forms a sloping sand bed, which subsequently ensures the aperture of the fractures. This research provides a fresh perspective on the influence of fracture roughness on proppant transport in offshore unconventional reservoirs and offers valuable considerations for the order of proppant injection.

Environmental Life Cycle Assessment of Innovative Ejectors Plant Technology for Sediment by-Pass in Harbours and Ports

Sedimentation is the natural process of sediment transportation and deposition in quiescent water conditions. Sedimentation can affect the functionality of ports, harbours and navigation channels by reducing water depth, making navigation difficult, if not impossible. Different solutions are available to guarantee infrastructure functionality against sedimentation, with maintenance dredging being the most widely adopted. Alternative technologies for dredging have been developed and tested to reduce the environmental concerns related to dredging operations. Among other solutions, applying a sediment by-pass system based on a jet pump emerged as one of the most promising. While the existing literature covers the techno-economic aspects of sediment by-pass systems, the environmental impacts must be better evaluated and assessed. This paper aims to resolve this gap by evaluating, through the ReCiPe2016 life cycle assessment (LCA) methodology, the environmental impact of an innovative sediment by-pass system called an “ejectors plant”. The LCA results are based on the demonstrator established in Cervia Harbour in Italy, which was extensively monitored for 15 months during its operation. This paper shows how energy consumption during the operation phase highly affects the considered midpoint and endpoint categories. For example, the GWP100 of the ejectors plant, considering the Italian electricity mix, equals 1.75 million tons of equivalent CO2 over 20 years, while under a low-carbon scenario, it is reduced to 0.17. In that case, material consumption in the construction phase becomes dominant, thus highlighting the importance of eco-innovation of ejectors plants to minimise oxidant formation. Finally, this paper compares the ejectors plant and traditional dredging through environmental LCA. The ejectors plant had a lower impact in all categories except for GWP-related categories. The sensitivity analysis showed how such a conclusion may be mitigated by considering different electricity mixes and maintenance dredging working cycles.

Visualization of ER-to-Golgi trafficking of procollagen X.

Collagen is the most abundant protein in the extracellular matrix of animals, and 28 types of collagen have been reported in humans. We previously analyzed the endoplasmic reticulum (ER)-to-Golgi transport of fibril-forming type III collagen (Hirata et al. 2022) and network-forming type IV collagen (Matsui et al. 2020), both of which have long collagenous triple-helical regions. To understand the ER-to-Golgi trafficking of various types of collagens, we analyzed the transport of short-chain type X collagen in this study. We fused cysteine-free GFP to the N-telopeptide region of procollagen X (GFP-COL10A1), as employed in our previous analysis of procollagens III and IV, and analyzed its transport by live-cell imaging. Procollagen X was transported to the Golgi apparatus via vesicular and tubular carriers containing ERGIC53 and RAB1B, similar to those used for procollagen III. Carriers containing procollagen X probably used the same transport processes as those containing conventional cargoes such as ⍺1-antitrypsin. SAR1, TANGO1, SLY1/SCFD1, and BET3/TRAPPC3 were required for trafficking of procollagen X, which are different from the factors required for trafficking of procollagens III (SAR1, TANGO1, and CUL3) and IV (SAR1 and SLY1/SCFD1). These findings reveal that accommodation of various types of collagens with different shapes into carriers may require fine-tuning of the ER-to-Golgi transport machinery.Key words: collagen, GFP-procollagen X, ER-to-Golgi trafficking, export from ER, TANGO1.

IMPROVEMENT OF THE TECHNOLOGICAL PROCESS OF PERISHABLE GOODS DELIVERY IN THE CITY OF KHARKIV

The article analyses the existing methods for building perishable goods delivery technologies and identifies strategies to study the prospects for developing perishable goods delivery systems, which allowed the authors to formulate the research objective in this development. The chosen topic is quite relevant since the formation of rational transport and technological schemes for the delivery of perishable goods allows for increasing the efficiency of resource use, decreasing the cost of their delivery, and reducing the delivery time of perishable goods. One of the ways to improve the efficiency of perishable goods delivery and reduce delivery time is to determine rational distribution routes and rational brands of rolling stock. The study established that foreign scientists have proposed solutions related to the construction of transport and technological schemes for the delivery of perishable goods, taking into account the choice of vehicles and routes for the delivery of goods. Most of these solutions focused on determining the appropriate loading capacity of rolling stock and the optimal delivery routes for perishable goods. A result of the conducted research was a proposed methodology for a comprehensive improvement of the perishable goods delivery process, consisting of determining rational distribution routes for a selected set of vehicles with different loadings. The authors implemented the software for the algorithm for choosing routes for vehicles of various capacities with the definition of the core technical and operational and technical and economic indicators of efficiency of the delivery process of perishable goods. The software implementation of the algorithm for selecting routes for vehicles of different capacities with the determination of the core technical and operational and technical and economic indicators of the efficiency of the delivery process of perishable goods allows one to quickly, in real-time, perform calculations and determine the rational parameters of the transport process and choose the appropriate routes and rolling stock. Keywords: perishable goods, cargo delivery, distribution routes, truck capacity, costs.

Development of the logistics potential of railway transport

An analysis of freight transport statistics over the past 10 years shows sensitivity to political influences from almost all modes of transport to one degree or another, including rail. At the same time, the participation of rail transport in the total volume of freight traffic in recent years can be estimated at 17–18 %. In recent years, there has been a trend towards an increase in the railway transportation sector in the total volume of freight. In order to ensure the technological sovereignty of the Russian Federation, it is necessary to take a number of technical, organizational and managerial decisions to offset the negative consequences. The development of domestic logistics potential involves the development of international transport corridors that will connect the macroeconomic regions of the north, south, east and west. This will certainly have an impact on the global economy as a whole. Therefore, the main task is to develop effective interaction between participants in transport processes both on related modes of transport, as well as the largest representatives of the operator and logistics business, cargo-forming enterprises. In this regard, the current situation has been analyzed using a tool to identify competitive advantages in the domestic market and in conditions of global competition.

Zosuquidar Promotes Antitumor Immunity by Inducing Autophagic Degradation of PD-L1.

The intracellular distribution and transportation process are essential for maintaining PD-L1 (programmed death-ligand 1) expression, and intervening in this cellular process may provide promising therapeutic strategies. Here, through a cell-based high content screening, it is found that the ABCB1 (ATP binding cassette subfamily B member 1) modulator zosuquidar dramatically suppresses PD-L1 expression by triggering its autophagic degradation. Mechanistically, ABCB1 interacts with PD-L1 and impairs COP II-mediated PD-L1 transport from ER (endoplasmic reticulum) to Golgi apparatus. The treatment of zosuquidar enhances ABCB1-PD-L1 interaction and leads the ER retention of PD-L1, which is subsequently degraded in the SQSTM1-dependent selective autophagy pathway. In CT26 mouse model and a humanized xenograft mouse model, zosuquidar significantly suppresses tumor growth and accompanies by increased infiltration of cytotoxic T cells. In summary, this study indicates that ABCB1 serves as a negative regulator of PD-L1, and zosuquidar may act as a potential immunotherapy agent by triggering PD-L1 degradation in the early secretory pathway.

Electronic structure and phonon transport properties of HfSe2 under in-plane strain and finite temperature

The electronic structure and phonon transport properties of HfSe2 under different in-plane strains at finite temperatures are systematically investigated by combining first-principles calculations with machine learning force field molecular dynamics simulations. Within a strain range of -3% to 3%, the electronic band gap value of HfSe2 varies between 0.39 and 0.87 eV. Under compressive strain, the conduction band minimum moves towards the Fermi level, with the distribution of electrons near the valence band maximum becoming more delocalized. This will reduce the scattering of electrons during the transport process, helping to improve the carrier mobility. Under tensile strain, the localization of the density of states near the valence band maximum is strengthened, accompanied by enhanced metallic properties of the Hf-Se bonds, which facilitates the enhancement of the thermoelectric power factor. Both compressive and tensile strains intensify the coupling of phonon normal modes with phonon scattering, and elevating the temperature amplifies this impact. The anharmonicity-induced reduction in phonon frequencies is especially pronounced for modes in the vicinity of the Debye frequency. This not only curtails the phonon lifetimes but also diminishes the lattice thermal conductivity through the enhancement of vibrational coupling among optical branches and the reduction of the group velocity in acoustic branches. These results demonstrate the synergistic effects of strain and temperature on the electronic structure and phonon transport of HfSe2.

Diffusiophoresis promotes phase separation and transport of biomolecular condensates

The internal microenvironment of a living cell is heterogeneous and comprises a multitude of organelles with distinct biochemistry. Amongst them are biomolecular condensates, which are membrane-less, phase-separated compartments enriched in system-specific proteins and nucleic acids. The heterogeneity of the cell engenders the presence of multiple spatiotemporal gradients in chemistry, charge, concentration, temperature, and pressure. Such thermodynamic gradients can lead to non-equilibrium driving forces for the formation and transport of biomolecular condensates. Here, we report how ion gradients impact the transport processes of biomolecular condensates on the mesoscale and biomolecules on the microscale. Utilizing a microfluidic platform, we demonstrate that the presence of ion concentration gradients can accelerate the transport of biomolecules, including nucleic acids and proteins, via diffusiophoresis. This hydrodynamic transport process allows localized enrichment of biomolecules, thereby promoting the location-specific formation of biomolecular condensates via phase separation. The ion gradients further impart directional motility of condensates, allowing them to exhibit enhanced diffusion along the gradient. Coupled with a reentrant phase behavior, the gradient-induced enhanced motility leads to a dynamical redistribution of condensates that ultimately extends their lifetime. Together, our results demonstrate diffusiophoresis as a non-equilibrium thermodynamic force that governs the formation and transport of biomolecular condensates.