External Carriers Research Articles

Polyethylene Glycol-Enzyme Nanocomplexes as Carrier-free Biocatalyst for Pickering Interfacial Catalysis.

PEG-enzyme nanocomplexes are prepared and stabilized in an oil-in-water-type emulsion for Pickering interfacial biocatalysis, and these nanocomplexes function as catalysts and emulsifiers at the emulsion interface. The nanocomplexes are self-assembled by cross-linking mPEG-ALD with lipase, without complicated synthesis steps, toxic chemical reagents, and external carriers. Moreover, the mild cross-linking process preserves the original structure of the enzyme, the retention rate of enzyme activity is 82.1%, and the nanocomplexes are used to emulsify biphasic aqueous-organic solution into Pickering emulsion. The system exhibits excellent reusability, with enzyme activity remaining at 86.05% after five cycles, providing a desirable eco-friendly platform for carrier-free Pickering interfacial biocatalysis.

AC-driven QLED based on far-field effect of Au NPs

As the pixel size continues to shrink, conventional display devices are unable to satisfy the increasing demand. Therefore, a novel light-emitting device has garnered significant attention. This device emitted light under an alternating current (AC) electric field and blocked the injection of external carriers by using the insulating layer. However, at the same time, this approach leads to a reduction in brightness. In this paper, we have realized the performance enhancement of AC-driven QLEDs by incorporating Au NPs of different sizes in PEDOT:PSS. Our investigation reveals that Au NPs of greater size exhibit a notable enhancement of the brightness, rising from 5512 cd/m2 to 7234 cd/m2, representing a substantial increase of approximately 31.2 %. It demonstrates the great potential of the "far-field" effect in AC-driven QLEDs.

Intertumoral and intratumoral barriers as approaches for drug delivery and theranostics to solid tumors using stimuli-responsive materials.

The solid tumors provide a series of biological barriers in cellular microenvironment for designing drug delivery methods based on advanced stimuli-responsive materials. These intertumoral and intratumoral barriers consist of perforated endotheliums, tumor cell crowding, vascularity, lymphatic drainage blocking effect, extracellular matrix (ECM) proteins, hypoxia, and acidosis. Triggering opportunities have been drawn for solid tumor therapies based on single and dual stimuli-responsive drug delivery systems (DDSs) that not only improved drug targeting in deeper sites of the tumor microenvironments, but also facilitated the antitumor drug release efficiency. Single and dual stimuli-responsive materials which are known for their lowest side effects can be categorized in 17 main groups which involve to internal and external stimuli anticancer drug carriers in proportion to microenvironments of targeted solid tumors. Development of such drug carriers can circumvent barriers in clinical trial studies based on their superior capabilities in penetrating into more inaccessible sites of the tumor tissues. In recent designs, key characteristics of these DDSs such as fast response to intracellular and extracellular factors, effective cytotoxicity with minimum side effect, efficient permeability, and rate and location of drug release have been discussed as core concerns of designing paradigms of these materials.

Influencing Factors of Street Vitality in Historic Districts Based on Multisource Data: Evidence from China

Amid urban expansion, historic districts face challenges such as declining vitality and deteriorating spatial quality. Using the streets of Xi’an’s historical and cultural district as examples, this research utilizes multisource data, including points of interest (POIs), street view images, and Baidu heatmaps, alongside analytical techniques such as machine learning. This study explores the determinants of street vitality from the dual perspectives of its external manifestation and spatial carriers. A quantitative framework for measuring street vitality in historic districts is established, thoroughly examining the driving factors behind street vitality. Additionally, the relationship between built environment indicators and street vitality is elucidated through statistical analysis methods. The findings reveal significant, time-varying influences of these spatial carriers on human vitality, with distinct spatial distribution patterns of human activity across different times, and the significance of the influence of external representations of human vitality and various types of spatial carriers varies over time. Based on these insights, this paper proposes strategies for enhancing the vitality of historic streets, aiming to rejuvenate and sustain the diverse and dynamic energy of these districts. It provides a foundation for revitalizing the vigor of cultural heritage zones and offers strategies applicable to similar urban contexts.

Bias‐Switchable Dual‐Mode Organic Photodiodes Enabled by Manipulation of Interface Layers

AbstractBias‐switchable dual‐mode organic photodiodes (OPDs) that integrate photovoltaic and photomultiplication modes are recently developed and shown prospects in complex light‐intensity applications. Yet, the device physics that focuses on carrier dynamics is still a challenge and needs to be further explored. Herein, dual‐mode OPDs are developed through interface layer manipulation, that is, introducing cathode interface layers (typically, ZnxO:D149) with deep energy levels and abundant bulk defects and an anode interface layer of thermally‐evaporated ZnO (e‐ZnO) with a wide bandgap. Under reverse bias, ZnxO:D149 forms a barrier wall to effectively block external holes and maintain the photovoltaic mode of the OPDs. Under forward bias, the capturing effect of ZnxO:D149 and blocking effect of e‐ZnO help to reduce the dark current; when under illumination, defect traps capture photo‐generated holes, eliminating the barrier traps and promoting unobstructed injection of external carriers to achieve photomultiplication effect. The typical device delivers high specific detectivity (>1012 Jones) and fast response (<40 µs), and exhibits disparate external quantum efficiency in two operating modes, showing promise for simultaneously detecting faint and strong light. This general strategy for preparing dual‐mode OPDs is compatible with CMOS processing technology and meets the miniaturization and integration requirements of next‐generation detection systems.

E-Suture: Mixed-Conducting Suture for Medical Devices.

Modern implantable bioelectronics demand soft, biocompatible components that make robust, low-impedance connections with the body and circuit elements. Concurrently, such technologies must demonstrate high efficiency, with the ability to interface between the body's ionic and external electronic charge carriers. Here, a mixed-conducting suture, the e-suture,is presented. Composed of silk, the conducting polymer poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), and insulating jacketing polymers,the resulting e-suture has mixed-conducting properties at the interface with biological tissue as well as effective insulation along its length. The e-suture can be mechanically integrated into electronics, enabling the acquisition of biopotentials such as electrocardiograms, electromyograms, and local field potentials (LFP). Chronic, in vivo acquisition of LFP with e-sutures remains stable for months with robust brain activity patterns. Furthermore, e-sutures can establish electrophoretic-based local drug delivery, potentially offering enhanced anatomical targeting and decreased side effects associated with systemic administration, while maintaining an electrically conducting interface for biopotential monitoring. E-sutures expand on the conventional role of sutures and wires by providing a soft, biocompatible, and mechanically sound structure that additionally has multifunctional capacity for sensing, stimulation, and drug delivery.

STREAMS HEAT INTEGRATION IN THE SEPARATION PROCESS OF THE FURFURAL-WATER HETEROAZEOTROPIC MIXTURE BY USING TWO STRETCHING COLUMNS

The process of azeotropic mixtures rectification takes place in many branches of the chemical industry. This process requires significant energy consumption both for heating and evaporation of process streams, and for vapor condensation and cooling of products. The consumption of external energy essentially depends on the methods of separation processes organization. Pinch analysis is one of the modern methods for designing chemical-technological systems with the aim of optimal use of external energy sources by maximizing the heat integration of system process streams, taking into account the limitations of a particular manufacture, the requirements of environmental safety and environmental protection. In this paper the heat integration of the heteroazeotropic furfural-water mixture separation process by two columns was considered. In each column the azeoptrope is a light-boiling one, and one of the mixture components is a low-boiling one. The heat and material balances of the rectifying plant were calculated and the table of its streams was formed, that is, the data of the chemical-technological system were extracted. From the total set of heat streams, the subset was selected for heat integration. Composite curves for the selected heat streams subject to heat integration were built and their relative position on the temperature-enthalpy diagram was analyzed. This analysis showed that for a certain value of the minimum temperature difference in the heat exchange equipment Тmin, there is a threshold problem. The problem was formulated for a value of Тmin slightly less than the threshold value that led to a slight increase in the consumption of external energy carriers. Options for further improvement of the network of heat exchangers were considered, and the occurrence of a cycle through the pseudopinch was identified. It gave possibility to remove a heat exchanger with a low load and redistribute this load among to other ones. Restoring Тmin in this case is impossible, because a strict restriction on the absence of hot utilities is accepted. Significant savings in external utilities load have been demonstrated. For retrofit modern Alfa Laval heat exchange equipment was selected for all the necessary positions.

Metatranscriptome revealed how carbon brush addition affected the fermentation of food wastewater in the low-temperature environment

Improving the anaerobic digestion (AD) performance in low-temperature environments has become a key factor in the development of waste treatment and resource recovery in cold regions. The utilization of external carriers to form a biofilm is the simplest and most practical way to enhance the psychrophilic AD performance in cold regions. In this study, the effect of carrier addition on the fermentation performance of low-temperature (15 ± 2 °C) food wastewater was investigated by forming biofilms with carbon brushes. The results showed that although the biofilm formation enhanced methane yields (15.24%), it also caused more accumulation of propionic acid (306.99–626.89 mg/L), and the concentration of acetic acid (86.78–254.71 mg/L) was relatively low. The microbial community revealed the highest abundance of the fermentative bacterium Firmicutes and the carbon brush carrier significantly increased its relative abundance (23.74%). Metatranscriptomic sequencing revealed that the abundance level of Clostridium, Bacteroides, Sedimentibacter and Pelotomaculum was the highest, reaching 80% in all groups. In addition, the abundance level of electroactive microorganisms in biofilms was higher, while the fermentation bacteria and methanogens were lower. This showed that biofilm can enrich more electroactive microorganisms, and granular sludge needs to enrich more fermentation bacteria and methanogens to ensure metabolic activity. Further studies have found that carbon metabolism had the highest activity (27.86%–30.39%) and H+-transporting ATPase (atp) was the most dominant functional enzyme (85.50%–86.65%) involved in electron transport in low-temperature fermentation of food wastewater. Interestingly, these expression levels of active granular sludge were higher than the biofilm formed by carbon brushes. Meanwhile, analysis of the methanogenic pathway found that active granular sludge tends to be directly metabolized to realize acetate to acetyl-CoA by acetyl-CoA synthetase (ACSS), while biofilms were not significantly different in the two metabolic pathways of acetate. These results deepen the understanding of treating low-temperature food wastewater.

In situ orderly self-assembly strategy affording NIR-II-J-aggregates for in vivo imaging and surgical navigation

J-aggregation, an effective strategy to extend wavelength, has been considered as a promising method for constructing NIR-II fluorophores. However, due to weak intermolecular interactions, conventional J-aggregates are easily decomposed into monomers in the biological environment. Although adding external carriers could help conventional J-aggregates stabilize, such methods still suffer from high-concentration dependence and are unsuitable for activatable probes design. Besides, these carriers-assisted nanoparticles are risky of disassembly in lipophilic environment. Herein, by fusing the precipitated dye (HPQ) which has orderly self-assembly structure, onto simple hemi-cyanine conjugated system, we construct a series of activatable, high-stability NIR-II-J-aggregates which overcome conventional J-aggregates carrier’s dependence and could in situ self-assembly in vivo. Further, we employ the NIR-II-J-aggregates probe HPQ-Zzh-B to achieve the long-term in situ imaging of tumor and precise tumor resection by NIR-II imaging navigation for reducing lung metastasis. We believe this strategy will advance the development of controllable NIR-II-J-aggregates and precise bioimaging in vivo.

Bio-Inspired Synthetic Hydrogen-Bonded Organic Frameworks for Efficient Proton Conduction.

Hydrogen-bonded organic frameworks (HOFs) are a rising class of promising proton-conducting materials. However, they always suffer from the inherent contradiction between chemical stability and proton conduction. Herein, inspired by the self-assembly of lipid bilayer membranes, a series of aminomethylphosphonic acid-derived single-component HOFs are successfully developed with different substituents attached to the phosphonate oxygen group. They remain highly stable in strong acid or alkaline water solutions for one month owing to the presence of charge-assisted hydrogen bonds. Interestingly, in the absence of external proton carriers, the methyl-substituted phosphonate-based HOF exhibits a very high proton conductivity of up to 4.2×10-3 Scm-1 under 80°C and 98% relative humidity. This value is not only comparable to that of HOFs consisting of mixed ligands but also is the highest reported in single-component HOFs. A combination of single-crystal structure analysis and density functional theory calculations reveals that the high conductivity is attributed to the strengthened H-bonding interactions between positively charged amines and negatively charged phosphonate groups in the channel of bio-inspired HOFs. This finding demonstrates that the well-defined molecular structure of proton conductors is of great importance in the precise understanding of the relationship between structure and property.

Comparison of pulsed electroacoustic and thermally stimulated depolarization current measurements of thermally poled PET electrets

We have compared measurements of a set of polyethylene terephthalate (PET) electret samples by means of pulsed electroacoustic method (PEA) and thermally stimulated depolarization current (TSDC) techniques. Samples where the α or the ρ relaxation is activated show uniform polarization and image charge at the electrodes. Different electrode configurations have been tested when external charge carriers are injected into the sample. In these experiments, differences in TSDC spectra are explained by the different blocking behavior of the electrodes. All in all, PEA in combination with TSDC turns out to be a useful technique in the study of thermally poled electrets.

PINCH-INTEGRATIONAL OPTIMIZATION OF HEAT EXCHANGE NETWORK OF THE HYDROLYTIC SULFURIC ACID CONCENTRATION PROCESS

The paper considers the question of the possibility of thermal energy saving at an industrial enterprise. As a means of optimizing energy consumption, one of the methods for integrating chemical-technological processes, pinch analysis, was used. It has been established that the problems of significant energy consumption are relevant for researchers and industrialists around the world, and scientists see their solution primarily in the development of alternative energy sources and modern methods of energy saving with well-predictable results. It is indicated that the target functions in this case can be combined: financial-energy and energy-environmental, since exactly these kinds of results are provided by the very essence of energy-and-resources saving applied to the industrial process.
 At the initial stage of the study, an analysis of thermal energy consumption structure provided by apparatuses in hydrolytic sulfuric acid concentration process was made. Based on its results, it was found that the existing minimum temperature difference in the system is far from the optimal and technically achievable value. Taking into account the confirmed energy-saving potential, its value was estimated. For this, the value of the present heat recovery in the system is established through calculation, and the volume of energy coming from external heat carriers and refrigerants is determined. Based on the calculation results, a Grid diagram and Composite curves of the specified technological process were constructed.
 At the second stage, optimization measures, which began with the choice of a new, lower value of the minimum temperature difference for the entire heat exchange network of this industrial plant, were carried out. For this value, shifted composite curves were constructed and an updated grid diagram was developed. In the integrated heat exchange network, there is three additional recuperative heat exchanger and were revised the operating modes of devices that it was decided to save. Based on the optimization results, a technological scheme of the hydrolytic sulfuric acid concentration process was designed while maintaining the key elements of the production technology.
 The result of the work is an optimized heat exchange network of the industrial enterprise section, which makes it possible to increase the thermal energy recuperation by 32,7 %, while reducing the consumption of external heat carriers by 30,3 %, as well as external refrigerants – by 50,1 %. The results obtained indicate a very high economic efficiency and a prospects of implementation the project into production.

Application of Topsis Reverse Logistics Operating Method

Coordination’s re-appropriation is becoming increasingly necessary because more and more organizations worldwide are unable to deal with their troubling versatile chains, re-appropriate exercises in coordination with the outsider coordinators (3PL) or professional co-operatives in coordination. Through redistributing teamwork exercises, businesses will focus on their business tasks at the core while at the same time achieving economic productivity and enhancing transport delivery and customer loyalty. Transport structure and the board of directors are of fundamental benefit to 3PLs. You can transport your own armada or haggle with at least one external carriers. In addition, 3PLs have traffic light inbound and outbound. To boost the courses, transport uses various transport methods and administration of installations. Switch coordination is one form of coordination that has an important impact on the board through ecological implementation and growing client awareness. The purpose of this paper is to enable heads of organization to determine most appropriate invert collaboration modes of operating with the complex models. There are three basic work method of coordinating for big corporations: self-supporting, joint endeavor and redistribute. To rank the other options, we applied TOPSIS as a dynamic apparatus. At long last, a model has been delineated to feature procedural execution of proposed model.

Vehicle routing problem for reverse logistics of End-of-Life Vehicles (ELVs)

Reverse logistics management of End-of-Life Vehicles (ELVs) is increasingly focusing on practical solutions for getting additional value from products at the end of their life. As automotive is one of the fastest-growing sectors, the number of ELVs to be collected and recycled has been steadily increasing due to more stringent regulations. On the other hand, the operational cost (transportation) of collecting ELVs might exceed half of the purchased price. Furthermore, parameters that influence the solution of the routing problem for the collection of ELVs tend to change due to the dynamic customers’ locations and variations in vehicle type and the condition of the vehicules at the end of their life. This research proposes a new reverse logistics routing problem for the collection of end-of-life vehicles. It combines the classical Vehicle Routing Problem (VRP) with the pick-up problem and additional constraints such as loading pick-up sequences, time-windows, multi-trips, heterogeneous internal fleet, and external carriers. We also developed an efficient heuristic to construct routes and assign dealers to truck routes for solving large and real-size instances in a reasonable time. In collaboration with a significant player in North America for ELVs recycling, we performed a sensitivity analysis to compare the industry’s current practices and the proposed method. The validation process with different instances demonstrates results consistency and provides useful managerial insights. Finally, sensitivity analysis shows potential changes in the solution performance regarding the penalty cost of unused internal fleet, the extra broker cost, the size of ELVs collected, and the number of the internal carriers’ truck fleet.

Distance discount in the green vehicle routing problem offered by external carriers

This study suggested a model for the Green Vehicle Routing Problem (GVRP) regarding distance discount strategy. For the first time,we defined distance discount strategy based on intervals for a vehicle routing problem. The proposed model attempts to minimize the total cost of the system by selecting the different vehicles and paths that have time and fuel constraints while external carriers offer the distance discount. This model is formulated by mixed-integer linear programming and classified as NP-hard. The feasibility of this issue depends on the location of customers and fuel stations. Two metaheuristic algorithms such as tabu search (TS) and simulated annealing (SA) have been developed beside the exact method, and the efficiency of our metaheuristic methods have been examined through 40 benchmark instances of different sizes and 16 randomly generated numerical instances. Computational results show superior performance of the simulated annealing in comparison with the tabu search for test problems and the cost efficiency owing to the distance discount from the organization's outlook.

High stability three-dimensional porous PtSn nano-catalyst for ethanol electro-oxidation reaction

ABSTRACT In addition to the theoretical research, direct ethanol fuel cells have great potential in practical applications. The performance of direct ethanol fuel cells largely depends on the electrocatalysts. Pt-based electrocatalysts have been promising candidates for advancing direct ethanol fuel cells for its high catalytic activity and great durability. Here, a PtSn catalyst with unique three-dimensional porous nanostructure has been designed and synthesized via a two-step liquid phase reduction reaction. Sn formed a self-supporting framework in PtSn alloy particles (∼3.5 nm). In ethanol electro-oxidation reaction, the PtSn catalyst exhibited high mass activity and excellent recycling time compared with that of Pt/C. After the morphology characterization before and after potential cycling, the PtSn alloy-based nano-catalyst showed good stability. The PtSn catalysts effectively avoid structural instability due to the external carriers, and prolong the leaching time of Sn. In addition, the introduction of a certain amount of Sn can also solve the poisoning phenomenon of active sites on Pt surface. The design strategy of porous alloy nano-catalyst sheds light on its applications in direct ethanol fuel cells.

Statistical Properties and Configurational Entropy of a Two-Dimensional Néel Magnetic Skyrmions Population

The study of the thermodynamic properties of topological defects is important not only for understanding their magnetic properties but also for suggesting novel applications. In this paper, the statistical and statistical thermodynamic properties of a population of Néel magnetic skyrmion diameters hosted in an ultrathin cylindrical dot is determined within a two-dimensional analytical approach. The statistical properties such as the skyrmion size are calculated in the region of skyrmion metastability and are compared with the ones obtained using a recent three-dimensional analytical approach based on the analogy with the Maxwell–Boltzmann distribution of dilute gas molecules. The investigation of the statistical thermodynamic properties focus on the calculation of the configurational entropy at thermodynamic equilibrium determined in the continuous limit from the Boltzmann order function. While the statistical properties are quantitatively similar passing from the two-dimensional to the three-dimensional approach, the configurational entropy calculated from the two-dimensional skyrmions distribution is considerably lower than the one obtained from the three-dimensional skyrmions distribution. Because of the strong resemblance between the statistical configurational entropy and Jaynes’s information entropy, it is suggested to use magnetic skyrmions as temperature and external field dependent information entropy carriers for a future potential technological application in the field of low-dimensional magnetic systems and skyrmionics.

Memristive and magnetoresistance effects of SnSe<sub>2</sub>

Memristor and magnetoresistance (MR) are widely used in the field of information storage. In recent years, SnSe<sub>2</sub>, as an information storage material with both memristor and MR effects, has received a lot of attention of the researchers. It is of great significance to further explore its electrical transport mechanism. In this paper, the high-purity bulk SnSe<sub>2</sub> samples are prepared by melting method together with spark plasma sintering. The <i>V</i>-<i>I</i> curves are measured under different temperatures and magnetic fields. The memristive and MR effect of SnSe<sub>2</sub> are systematically investigated. After the memristive characteristics are excluded from interfacial junction effect, phase transition and conductive wire channels, the memristive effect at different temperatures is attributed to the space charge limiting current effect under defect control. Under low electric field conditions, the internal carrier concentration of material is much higher than the injected carrier concentration and the <i>V</i>-<i>I</i> curve obeys ohmic conduction. When the voltage increases to the switching voltage <i>V</i><sub>on</sub>, the internal defects of the material are filled with the injected carriers as the transport time of the injected carrier is less than the dielectric relaxation time, and the <i>V</i>-<i>I</i> curves deviate from ohmic conductivity. When the voltage reaches the transition voltage <i>V</i><sub>TFL</sub>, the injected carrier increases exponentially, and the <i>V</i>-<i>I</i> curve presents negative differential phenomenon. Finally, the space charge inside the material will limit the further injection of external carriers, and the <i>V</i>-<i>I</i> curve follows the Child law. As the temperature decreases to 10 K, the memristive phenomenon weakens because a large number of defects for accepting the injected carriers are reduced due to the decrease of impurity ionization at low temperatures. At the same time, the sample exhibits a large negative MR at 10 K and 100 K. When impurity scattering predominates, the electrons will be subjected to multiple scattering by the impurities, resulting in localization of carriers. The negative MR effect is related to the inhibition of the carrier localization by the magnetic field. In our work, a large negative MR of about –37% at 0.6 T and 10 K are obtained, which is likely to originate from the disordered distribution of Se vacancy in the material. With the increase of temperature, the scattering mechanism gradually evolves from the impurity scattering into the lattice scattering, and the negative MR effect gradually develops into the positive MR effect.

High vacuum equipment for the measurement of the macroscopic dipole moment of polar molecular crystals.

Polar crystals placed into a charged plate capacitor may experience a mechanical torque. Mounting crystals on a spiral spring allows us to measure the momentum and thus the macroscopic dipole moment of a crystal object. To exclude the influence of ambient conditions (air, ions, electrons), experiments are performed in a high vacuum. Following text book knowledge, polar crystals show a surface charge density especially for faces involving the polar crystal axis. For ambient conditions, it is assumed that external charge carriers compensate the surface charge. Here, we present unique equipment by which the dipole moment of crystals can be measured also when the charge carrying parts of a crystal were cut off by two metallic blades. Present measurements for α-resorcinol (mm2) allow us to conclude that (a) as grown polar crystals measured under the high vacuum condition show a macroscopic dipole moment, (b) the weighted dipole moment increases after cutting the main polar faces, and (c) the weighted dipole moment decreased after exposure to ambient air.

A column‐generation‐based approach to fleet design problems mixing owned and hired vehicles

AbstractWe look at the problem of choosing a fleet of vehicles to carry out delivery tasks across a long time horizon. The delivery quantities may vary significantly from day to day, and from season to season, and the underlying routing problem may have rich constraints, for example, time windows, multiple compartments, multiple commodities, and compatibility constraints. We consider the option of hiring extra vehicles from external carriers in order to efficiently carry out the day‐to‐day operations while containing the costs of owning the fleet. The goal is to design a fleet so as to minimize the sum of costs of routing the fleet every day of the horizon, the acquisition costs, the maintenance costs, and the costs of hiring external vehicles. In the literature, there is no previous work on fleet design for a long time horizon, which also considers the hiring options. We propose to tackle the problem using column generation and develop three different heuristics. The methods proposed are tested and compared on a set of real‐world problems. It is also shown how introducing the possibility of hiring helps reducing the overall cost and the number of idle vehicles over the planning horizon.