Multiple Buffers Research Articles

Catechol-modified stabilizer facilitates impulsive ligand functionalization of particulates and membrane modification of cells

Ligand-functionalized particulates have received considerable attention for targeted drug delivery. Previous studies have reported several methods for functionalizing various molecules on the surfaces of nano- and micro-particulates which involve multiple steps, reaction buffers and chemicals, and long reaction times. Here, we report a single-step method that uses catechol chemistry to rapidly functionalize ligands on the surfaces of polymeric nanoparticles (NPs). We synthesized dopamine-conjugated poly (ethylene-alt-maleic acid) (D-PEMA) by performing a nucleophilic addition reaction between dopamine and poly (ethylene-alt-maleic anhydride) (PEMAnh). We then used D-PEMA as a stabilizer while preparing NPs which led to the construction of NPs that were non-adhesive per se but provided active sites for conjugating multiple different ligands in an alkaline buffer via Michael's addition and Schiff's base substitution reactions. The ligand-functionalized NPs were nontoxic and effectively internalized by both primary and cancer cells. In addition, NPs prepared using the modified stabilizer conjugated rapidly on the surfaces of pancreatic islets in alkaline conditions. Our study provides evidence that the modified stabilizer is versatile and has the potential for drug delivery applications and cell surface modifications.

Alleviating bus bunching via modular vehicles

The notorious phenomenon of bus bunching prevailing in uncontrolled bus systems produces irregular headways and downgrades the level of service by increasing passengers’ expected waiting time. Modular autonomous vehicles (MAVs), due to their ability to split and merge en route, have the potential to help both late and early buses recover from schedule deviation while providing continuous service. In this paper, we propose a novel bus bunching alleviation strategy for MAV-aided transit systems. We first consider a soft vehicle capacity constraint and establish a continuum approximation (CA) model (Model I) to capture the system dynamics intertwined with the MAV splitting and merging operations, and then establish an infinite-horizon stochastic optimization model to determine the optimal splitting and merging strategy. To capture the reality that passengers may fail to board an overcrowded bus, we propose a second model (Model II) by extending Model I to accommodate a hard vehicle capacity constraint. Based on the characteristics of the problem, we develop a customized deep Q-network (DQN) algorithm with multiple relay buffers and a penalized ruin state applicable for both models to optimize the strategy for each MAV. Numerical results show that the strategy obtained via the DQN algorithm is an effective bunch-proof strategy and has a better performance than the myopic strategy for MAV-aided systems and the two-way-looking strategy for conventional bus systems. Sensitivity analyses are also conducted to examine the effectiveness and benefits of the proposed strategy across different operation scenarios.

Model-Based Analysis of Arsenic Retention by Stimulated Iron Mineral Transformation under Coastal Aquifer Conditions.

A multitude of geochemical processes control the aqueous concentration and transport properties of trace metal contaminants such as arsenic (As) in groundwater environments. Effective As remediation, especially under reducing conditions, has remained a significant challenge. Fe(II) nitrate treatments are a promising option for As immobilization but require optimization to be most effective. Here, we develop a process-based numerical modeling framework to provide an in-depth understanding of the geochemical mechanisms controlling the response of As-contaminated sediments to Fe(II) nitrate treatment. The analyzed data sets included time series from two batch experiments (control vs treatment) and effluent concentrations from a flow-through column experiment. The reaction network incorporates a mixture of homogeneous and heterogeneous reactions affecting Fe redox chemistry. Modeling revealed that the precipitation of the Fe treatment caused a rapid pH decline, which then triggered multiple heterogeneous buffering processes. The model quantifies key processes for effective remediation, including the transfer of aqueous As to adsorbed As and the transformation of Fe minerals, which act as sorption hosts, from amorphous to more stable phases. The developed model provides the basis for predictions of the remedial benefits of Fe(II) nitrate treatments under varying geochemical and hydrogeological conditions, particularly in high-As coastal environments.

39‐1: Invited Paper: An Improved Gate Driver Using Oxide TFTs for Large OLED Displays

In this paper, we present the small area and high reliable gate driver in panels using a‐IGZO TFTs for large OLED displays. The proposed gate driver circuit has a small area structure with multiple output buffers connected to one shift register circuit. To lower the voltage stress of the pull‐down TFTs, which have the highest voltage stress among the TFTs of the gate driver, the initial voltage of those TFTs is set to low and increases according to the threshold voltage shift of TFTs during operation. It could be implemented by sensing the degradation of the TFTs using the programmable DC driving method. With these technologies, we were able to reduce the gate driver design area by 40% and improve the reliability by 30% despite reducing the circuit area. We successfully developed OLED TVs from 42 inches to 97 inches using the proposed gate driver.

A multiple buffering high-fall protection structure and its impact response

High-fall accidents are the most serious safety accidents in the global construction of tall buildings, and existing techniques cannot effectively prevent large-energy impact accidents such as the overall fall of construction formwork, resulting in huge safety risks. Therefore, this paper proposed a flexible protection structure with multiple buffering mechanisms by using a high-strength steel wire net as the intercepting component, and energy dissipators and buffer supports as the buffering and energy dissipation devices. Based on the mechanical model of the critical components, established a simulation model for the overall falling dynamic impact protection of construction formwork, and carried out four cases of parameter analyses that used the material of the intercepting net, whether to use energy dissipators and buffer support as control variables. The analyses show that the multiple buffering and energy dissipation mechanisms composed of steel wire net, energy dissipators, and buffer supports can effectively reduce the response of each component. Nine sets of parametric analyses based on the finalized structure were conducted with the stiffness of the intercepting net and energy dissipator as parameters The results indicate that the smaller the stiffness of the intercepting net and energy dissipator, the better the structural performance. The novel structure proposed in this paper can effectively protect against large-energy falling object impacts and improve the safety of building construction.

In Vitro Characterization and Rescue of VX Metabolism in Human Liver Microsomes.

Venomous agent X (VX) is an organophosphate acetylcholinesterase (AChE) inhibitor, and although it is one of the most toxic AChE inhibitors known, the extent of metabolism in humans is not currently well understood. The known metabolism in humans is limited to the metabolite identification from a single victim of the Osaka poisoning in 1994, which allowed for the identification of several metabolic products. VX has been reported to be metabolized in vitro by paraoxonase-1 and phosphotriesterase, although their binding constants are many orders of magnitude above the LD50, suggesting limited physiologic relevance. Using incubation with human liver microsomes (HLMs), we have now characterized the metabolism of VX and the formation of multiple metabolites as well as identified a Food and Drug Administration-approved drug [ethylenediaminetetraacetic acid (EDTA)] that enhances the metabolic rate. HLM incubation alone shows a pronounced increase in the metabolism of VX compared with buffer, suggesting that cytochrome P450-mediated metabolism of VX is occurring. We identified a biphasic decay with two distinct rates of metabolism. The enhancement of VX metabolism in multiple buffers was assessed to attempt to mitigate the effect of hydrolysis rates. The formation of VX metabolites was shown to be shifted with HLMs, suggesting a pathway enhancement over simple hydrolysis. Additionally, our investigation of hydrolysis rates in various common buffers used in biologic assays discovered dramatic differences in VX stability. The new human in vitro VX metabolic data reported points to a potential in vivo treatment strategy (EDTA) for rescue in individuals that are poisoned though enhancement of metabolism alongside existing treatments. SIGNIFICANCE STATEMENT: Venomous agent X (VX) is a potent acetylcholinesterase inhibitor and chemical weapon. To date, we do not possess a clear understanding of its metabolism in humans that would assist us in treating those exposed to it. This study now describes the human liver microsomal metabolism of VX and identifies ethylenediaminetetraacetic acid, which appears to enhance the rate of metabolism. This may provide a potential treatment option for human VX poisoning.

Performance of a Synchronisation Station with Abandonment

The paper presents a Markovian queueing model for assessing the performance of synchronisation between stations in a production system. The system at hand consists of K distinct buffers, each buffer storing an item that is needed for the next production stage. Departures are immediate when all items are present. Due to the presence of multiple buffers, there is no reasonably fast way to calculate the stationary distribution of the Markov chain. Therefore, we focused on the series expansion of the stationary distribution in terms of the arrival rate. We provide a fast algorithm for calculating these terms. Comparing our results with stochastic simulation, we show that the expansion approach converges to the simulated values for a wide range of arrival rates.

Highly immersive imaging: Depth of field effect implemented through ray tracing with multiple samples

This paper explores the implementation of depth of field effects through ray tracing with multiple samples. We focus on simulating the imaging process of the human eye, giving more consideration to the factors influencing the depth of field effect. Building upon ray tracing shading computations, we have employed a multi-sampling technique for rendering. This approach complements spatial information in the two-dimensional image, providing accurate depth of field effects. Moreover, as this process closely resembles the way the human eye naturally captures images, it results in a more immersive visual experience. Additionally, based on the advantageous features of parallel computing in distributed ray tracing, we explore an implementation scheme for parallel computing acceleration with multiple buffers. As the number of sampling points increases, rendering quality improves significantly, accompanied by substantial acceleration. Finally, we discuss the limitations of our method and potential directions for improvement, as well as future application scenarios in the fields of computer graphics and mixed reality.

Surrounding greenness is associated with lower risk and burden of low birth weight in Iran

The nexus between prenatal greenspace exposure and low birth weight (LBW) remains largely unstudied in low- and middle-income countries (LMICs). We investigated a nationwide retrospective cohort of 4,021,741 live births (263,728 LBW births) across 31 provinces in Iran during 2013–2018. Greenness exposure during pregnancy was assessed using satellite-based normalized difference vegetation index (NDVI) and enhanced vegetation index (EVI). We estimated greenness-LBW associations using multiple logistic models, and quantified avoidable LBW cases under scenarios of improved greenspace through counterfactual analyses. Association analyses provide consistent evidence for approximately L-shaped exposure-response functions, linking 7.0–11.5% declines in the odds of LBW to each 0.1-unit rise in NDVI/EVI with multiple buffers. Assuming causality, 3931–5099 LBW births can be avoided by achieving greenness targets of mean NDVI/EVI, amounting to 4.4–5.6% of total LBW births in 2015. Our findings suggest potential health benefits of improved greenspace in lowering LBW risk and burden in LMICs.

Analysis of Land Use Developments Along the LRT Line (Case Study: Polresta, Jakabaring and DJKA Station’s)

Transportation has become a basic need that plays an important role in people's lives. To reach a place, a high level of accessibility is required. A high level of accessibility will affect the number of people coming to an area. Many people will affect the number of activities that require land. Therefore, this study aims to analyze land use trends that occurred in the time period before and after the South Sumatra LRT. LRT or Light Rail Transit is a type of public transportation in the form of light rail operating in urban areas. LRT is the first light rail transportation in Indonesia right in Palembang City. Therefore, it is interesting to see its relation to land change along the LRT route. This research was conducted at three stations which were case studies, namely Polresta, Jakabaring and DJKA stations. This station was chosen because it is in Jakabaring. Jakabaring was chosen as the research area because it is a sub-district which is located on the border with other regencies but is still passed by the LRT. This research is a qualitative research using the overlay before-after analysis method through spatial data. This research uses the help of Archgis software, through Intersect tools and multiple ring buffers. The results of the analysis are then used as data for further analysis using a pivot table in excel. The results of this analysis prove that there is a tendency for changes in land use within a certain radius. The trend is in the form of changes in land from swamps or paddy fields to deserted, trade and services as well as offices.

A step closer to continuous buffer preparation from solids: Predicting powder compaction and how to prevent it

The preparation of buffer solutions used in the biopharmaceutical industry is typically performed manually by the addition of one or multiple buffering reagents to water. Recently, the adaptation of powder feeders for continuous solid feeding was demonstrated for continuous buffer preparation. However, the intrinsic characteristics of powders can change the stability of the process, due to the hygroscopic nature of some substances and humidity-induced caking and compaction behavior, but there is no simple and easy methodology available for predicting this behavior for buffer species. To predict which buffering reagents are suitable without special precautions and investigate their behavior, force displacement measurements were conducted with a customized rheometer over 18 h. While most of the eight investigated buffering reagents indicated uniform compaction, especially sodium acetate and dipotassium hydrogen phosphate (K2HPO4) showed a significant increase in yield stress after 2 h. Experiments conducted with a 3D printed miniaturized screw conveyor confirmed the increased yield stress measurements by visible compaction and failure of the feeding. By taking additional precautions and adjusting the design of the hopper, we demonstrated a highly linear profile of all buffering reagents over a duration of 12 and 24 h. We showed that force displacement measurements accurately predict the behavior of buffer components in continuous feeding devices for continuous buffer preparation and are a valuable tool to identify buffer components that need special precautions. Stable, precise feeding of all tested buffer components was demonstrated, highlighting the importance of identifying buffers that need a specialized setup with a rapid methodology.

Measuring Accessibility to Health Care Centers in the City of Al-Mafraq Using Geographic Information Systems

This study aims at measuring, analyzing, and evaluating accessibility to health care centers in the city of Al-Mafraq in order to determine their distribution efficiency and their spatial suitability for residential neighborhoods in the city using geographic information systems. It also aims at analyzing the geographical characteristics of the health centers locations in the city and determine their service ranges at the level of the residential neighborhoods in the city (Service Areas, Closest Facility, Location-Allocation, Multiple Ring Buffers). The study found that there is a significant difference and disparity in the ease of access to the health centers in the city of Mafraq. Most of the residential neighborhoods on the outskirts of the city suffer from difficult accessibility to the health centers such as the Industrial City, King Abdullah, Prince Hamzah and Al-Mazzeh neighborhoods in the south; and, Al-Nasr and Al-Jundi neighborhoods in the north. The study also found that the locations of Al-Hussein neighborhood health center and the Southern neighborhood health center were the easiest to reach compared to the other health centers in the city based on the distance and time factors. This research contributes to a better understanding of the geographical accessibility of the population to health care center, helping to identify polarization trends. The results obtained can help decision-makers develop urban planning strategies and optimize investments in health care infrastructure. Future studies will consider the use of other means of transport and other time slots.

A two-echelon location routing problem with mobile satellites for last-mile delivery: mathematical formulation and clustering-based heuristic method.

In last-mile delivery, the turbulence of traffic uncertainties is often solved by establishing and utilizing multiple buffering warehouses (satellites) with setup and operational costs, which are very costly in implementation. This distribution system involving satellites is often derived as the two-echelon location routing problem (2E-LRP). This study proposes a new variety of 2E-LRP problems with mobile satellites, called 2E-LRP-MS, which aims to reduce the cost of 2E-LRP by replacing fixed-located satellites with mobile satellites. Rather than utilizing fixed-location satellites, 2E-LRP-MS employs the first echelon vehicles (CT) as the mobile satellites moving around the city to replenish multiple second echelon vehicles (CF) en-route. For the cargo replenishment process, CT and CF can temporarily park at the consolidation points (CP), such as public parking lots or paid loading-unloading zones. With this flexibility, the high operational costs of the fixed-location satellites can be exchanged with CP's relatively low maintenance or renting fees, such as parking expenses. In this work, we introduce a heuristic method called clustering-based simultaneous neighborhood search (CSNS) to solve the proposed 2E-LRP-MS problem. The proposed CSNS considers the probabilistic mechanism and k-means clustering algorithm for facility selection, simultaneous neighborhood search to generate the routing solution, and local searches for optimizing the routing solution. Experimental results highlight the flexibility advantage of 2E-LRP-MS over 2E-LRP models and the searching efficiency of the proposed CSNS over the recent heuristic methods for two-echelon routing problems and commercial solver CPLEX.

Uniqueness and global stability of V-shaped fronts for the buffered bistable system in [formula omitted

This paper is devoted to V-shaped calcium concentration waves of the buffered bistable system in R2. We prove that multiple immobile buffers (where all buffers do not diffuse) do not affect the global asymptotic stability and uniqueness of V-shaped calcium concentration waves. The existence of such curved fronts has been proved in our previous work (Jia et al., 2022). However, the study of its stability is difficult since the buffers do not diffuse. We first apply the sliding method to construct a crucial sub-solution. Then, based on the super- and sub-solution method, and comparison principle, we achieve the global asymptotic stability of the V-shaped fronts.

Dynamic Response Analysis of a Novel Anti-Impact Pressure Balance Jack

Coal resources perform an important role in China’s energy structure. Hydraulic support is the main supporting equipment of fully mechanized mining face in coal mines. Because the hydraulic support frequently bears the impact pressure from the working face, it is very easy to cause failure of the balance jack. In order to solve the problem that the balance jack easily damaged by impact and improve the impact resistance of the hydraulic support, an improved fast response balance jack with multiple adaptive buffers was proposed in this paper. The energy dissipation characteristics of the balance jack were analyzed by establishing the mathematical model of the multiple buffering process of it. Based on ADAMS, the dynamic simulation model of the hydraulic support was constructed, and the mechanical response characteristics of the proposed balance jack and the traditional balance jack under different impact loads were compared and analyzed. By changing the equivalent stiffness of the novel balance jack system, the influence of different initial inflation pressure and length of the buffer cavity on the dynamic performance of the novel balance jack was discussed. The results show that compared with the traditional balance jack, the multi-adaptive response balance jack proposed in this paper can reduce the peak force of the hinge point by about 24.6% and the fluctuation frequency was also significantly reduced under the ultimate load condition at the front end of the top beam, which has better impact resistance. When the initial inflation pressure of the buffer cavity is 40~45 MPa and the initial length is less than 105 mm, a better buffer effect can be achieved. This study provides a new solution to solve the failure problem of the balance jack under the underground impact pressure and improve the safety and reliability of hydraulic support.

Associations between Traffic-Related Air Pollution and Cognitive Function in Australian Urban Settings: The Moderating Role of Diabetes Status.

Traffic-related air pollution (TRAP) is associated with lower cognitive function and diabetes in older adults, but little is known about whether diabetes status moderates the impact of TRAP on older adult cognitive function. We analysed cross-sectional data from 4141 adults who participated in the Australian Diabetes, Obesity and Lifestyle (AusDiab) study in 2011–2012. TRAP exposure was estimated using major and minor road density within multiple residential buffers. Cognitive function was assessed with validated psychometric scales, including: California Verbal Learning Test (memory) and Symbol–Digit Modalities Test (processing speed). Diabetes status was measured using oral glucose tolerance tests. We observed positive associations of some total road density measures with memory but not processing speed. Minor road density was not associated with cognitive function, while major road density showed positive associations with memory and processing speed among larger buffers. Within a 300 m buffer, the relationship between TRAP and memory tended to be positive in controls (β = 0.005; p = 0.062), but negative in people with diabetes (β = −0.013; p = 0.026) and negatively associated with processing speed in people with diabetes only (β = −0.047; p = 0.059). Increased TRAP exposure may be positively associated with cognitive function among urban-dwelling people, but this benefit may not extend to those with diabetes.

Global Building Morphology Indicators

Characterising and analysing urban morphology is a continuous task in urban data science, environmental analyses, and many other domains. As the availability and quality of data on them have been increasing, buildings have gained more attention. However, tools and data facilitating large-scale studies, together with an interdisciplinary consensus on metrics, remain scarce and often inadequate. We present Global Building Morphology Indicators (GBMI) — a three-pronged contribution addressing such shortcomings: (i) a comprehensive list of hundreds of building form multi-scale measures derived through a systematic literature review; (ii) a methodology and tool for the computation of these metrics in a database suited for big data and comparative studies, and release the code freely and open-source; and (iii) we carry out the computations using high performance computing, generating a public repository with data quantifying the form of selected urban areas around the world, and demonstrate their value with novel analyses comparing morphological parameters across cities. GBMI introduces a formalised, structured, modular, and extensible method to compute, manage, and disseminate urban indicators at a large scale and high resolution, while the precomputed dataset facilitates comparative studies. The theory and implementation traverse multiple scales: at the building level, both individual and contextual ones based on encircling buildings by multiple buffers, and aggregations at several hierarchical administrative levels and at multiple grids. Our open dataset, comprising billions of records on a growing scope of urban areas worldwide, is the most comprehensive instance of morphological data parametrising the individual building stock, supporting studies in urban analytics and a range of disciplines.

Traveling curved fronts in the buffered bistable systems in [formula omitted

We consider traveling curved fronts in the buffered bistable systems in R2 and show that multiple stationary buffers (where buffers do not diffuse) cannot prevent the existence of V-shaped calcium concentration waves. In other words, for the buffered bistable systems we prove that there exist V-shaped traveling fronts in R2 by constructing the proper supersolution and subsolution, applying the comparison principle and the fixed point theory.

Modeling the Gibbs–Donnan effect during ultrafiltration and diafiltration processes using the Poisson–Boltzmann theory in combination with a basic Stern model

The Gibbs–Donnan effect is a well-known phenomenon causing ions to be distributed unevenly across semi-permeable membranes that are permeable to ions but not to larger macromolecules such as proteins. In protein ultrafiltration and diafiltration (UF/DF) processes, this effect often leads to discrepancies between the pH and excipient concentrations in the final drug substance and in the DF buffer. In this work, a model describing the retentate and permeate composition throughout combined UF/DF processes is introduced. The model accounts for volume exclusion effects and electrostatic interactions between ions and the protein based on the Poisson–Boltzmann theory in combination with a basic Stern model. Advantages and limitations of the proposed model were analyzed using UF/DF experiments with multiple diafiltration buffers and proteins. A comparison between simulated and experimental permeate data showed good agreement for low to moderate Donnan potentials but model limitations for high Donnan potentials at protein concentration larger 100 gL -1 . In contrast, simulated retentate data showed good agreement for both low and high Donnan potentials and for protein concentrations up to 190 gL -1 . It was demonstrated that in this high protein concentration regime, the applied basic Stern model provides more accurate predictions compared to previous theories based on the Poisson–Boltzmann theory alone. This makes the model a valuable tool to describe discrepancies between pH and excipient concentrations in the final drug substance and DF buffer for highly concentrated protein formulations. As model predictions are based solely on structural information on the protein and the composition of the DF buffer, the model is particularly beneficial at an early stage in process development to streamline process development and improve process understanding. • Introduction of a model to describe the Gibbs–Donnan effect in UF/DF processes. • Advanced implementation of the cell model approximation. • Calibration solely based on structural information on the protein. • Validation using various proteins (up to 190 g/L) and buffer systems.

Repression and bystander mobilization in Africa

ABSTRACT How does exposure to government repression shape bystander willingness to mobilize into a protest or demonstration? A robust body of scholarship has argued that repression can backfire, motivating activists to take to the streets after the government clamps down. Yet, while the evidence is strong that highly motivated and risk-acceptant citizens are willing to step up, less is known about how repression affects the majority of citizens who do not frequently participate in protests. Yet, theories of civil resistance often depend on mobilizing bystanders. I examine this by drawing on geocoded survey data as well as incident-level data of repression across Africa. I measure each respondent’s exposure to government repression across multiple spatial and temporal buffers. Contrary to expectations in the civil resistance literature, I find that exposure to repression correlates with a lower willingness to consider joining a protest or demonstration. The closer a respondent is, both temporally and spatially, to an incident of repression, the less likely they are to report that they would consider joining a protest. The results are robust to additional testing specifications that address issues of endogeneity, social desirability bias, and omitted variable bias.