Filtration Step Research Articles

Carbon Nanotube Films with Fewer Impurities and Higher Conductivity from Aqueously Mono-Dispersed Solution via Two-Step Filtration for Electric Heating.

With the intensification of global climate problems, electric heating has recently attracted much attention as a clean and low-carbon heating method. Carbon nanotubes (CNTs) are an ideal medium for electric heating applications due to their excellent mechanical, electrical, and thermal properties. The preparation of electrothermal films based on an aqueous CNT dispersion as a raw material is environmentally friendly. However, in the traditional one-step filtration method, the residual excess dispersant and the small aspect ratio of the CNTs in the preparation process limit the performance of electrothermal CNT films. In this paper, we report a two-step filtration method that removes the free dispersant and small CNTs in the first filtration step and obtains denser CNT films by controlling the pores of the filter membrane in the second filtration step. The results suggest that, compared to the CNT1 film obtained from one-step filtration, the CNT1-0.22 film, obtained from two-step filtration using 1 and 0.22 μm membranes, has a smoother and flatter surface, and the surface resistance is 80.0 Ω sq-1, which is 29.4% lower. The convective radiation conversion efficiency of the CNT1-0.22 film is 3.36 mW/°C, which is 36.1% lower. We anticipate that such CNT films could be widely applied in building thermal insulation and underfloor heating.

Streamlined Analysis of Maternal Plasma Indicates Small Extracellular Vesicles are Significantly Elevated in Early-Onset Preeclampsia

Preeclampsia (PE) is a leading cause of maternal and fetal mortality and morbidity. While placental dysfunction is a core underlying issue, the pathogenesis of this disorder is thought to differ between early-onset (EOPE) and late-onset (LOPE) subtypes. As recent reports suggest that small extracellular vesicles (sEVs) contribute to the development of PE, we have compared systemic sEV concentrations between normotensive, EOPE, and LOPE pregnancies. To circumvent lengthy isolation techniques and intermediate filtration steps, a streamlined approach was developed to evaluate circulating plasma sEVs from maternal plasma. Polymer-based precipitation and purification were used to isolate total systemic circulating maternal sEVs, free from bias toward specific surface marker expression or extensive subpurification. Immediate Nanoparticle Tracking Analysis (NTA) of freshly isolated sEV samples afforded a comprehensive analysis that can be completed within hours, avoiding confounding freeze–thaw effects of particle aggregation and degradation.Rather than exosomal subpopulations, our findings indicate a significant elevation in the total number of circulating maternal sEVs in patients with EOPE. This streamlined approach also preserves sEV-bound protein and microRNA (miRNA) that can be used for potential biomarker analysis. This study is one of the first to demonstrate that maternal plasma sEVs harbor full-length hypoxia inducible factor 1 alpha (HIF-1α) protein, with EOPE sEVs carrying higher levels of HIF-1α compared to control sEVs. The detection of HIF-1α and its direct signaling partner microRNA-210 (miR-210) within systemic maternal sEVs lays the groundwork for identifying how sEV signaling contributes to the development of preeclampsia. When taken together, our quantitative and qualitative results provide compelling evidence to support the translational potential of streamlined sEV analysis for future use in the clinical management of patients with EOPE.

Understanding and Enhancing Silicon Nanoparticle Distribution during Electrode Processing

Silicon-dominant anodes are of great interest because of their potential to boost the cell-level energy of state-of-the-art Li-ion batteries. While silicon materials have been extensively studied, understanding interactions at the electrode level has recieved little attention, especially the coating process of Si particles, which plays an equally important role in unlocking the full potential of silicon anodes. Herein, the electrode processing of a Si-dominated anode (52.8 wt%, 3.5–4.5 mAh cm−2) is being investigated to understand the relationship of processing on the morphology and properties of Si anodes at the electrode level. It has been found that almost-undetectable Si agglomerates easily form during electrode processing, which grow into largeprotrusions after lithiation and trigger potential internal shorting and self-discharge problems. A facile slurry filtration step is proposed to homogenize the particle distribution within Si-dominant electrodes which improves the electrochemical performance and storage stability of Si-based Li ion batteries.

Multiple dyes applications for fluorescent convertible polymer capsules as macrophages tracking labels

Tracing individual cell pathways among the whole population is crucial for understanding their behavior, cell communication, migration dynamics, and fate. Optical labeling is one approach for tracing individual cells, but it typically requires genetic modification to induce the generation of photoconvertible proteins. Nevertheless, this approach has limitations and is not applicable to certain cell types. For instance, genetic modification often leads to the death of macrophages. This study aims to develop an alternative method for labeling macrophages by utilizing photoconvertible micron-sized capsules capable of easy internalization and prolonged retention within cells. Thermal treatment in a polyvinyl alcohol gel medium is employed for the scalable synthesis of capsules with a wide range of fluorescent dyes, including rhodamine 6G, pyronin B, fluorescein, acridine yellow, acridine orange, thiazine red, and previously reported rhodamine B. The fluorescence brightness, photostability, and photoconversion ability of the capsules are evaluated using confocal laser scanning microscopy. Viability, uptake, mobility, and photoconversion studies are conducted on RAW 264.7 and bone marrow-derived macrophages, serving as model cell lines. The production yield of the capsules is increased due to the use of polyvinyl alcohol gel, eliminating the need for conventional filtration steps. Capsules entrapping rhodamine B and rhodamine 6G meet all requirements for intracellular use in individual cell tracking. Mass spectrometry analysis reveals a sequence of deethylation steps that result in blue shifts in the dye spectra upon irradiation. Cellular studies on macrophages demonstrate robust uptake of the capsules. The capsules exhibit minimal cytotoxicity and have a negligible impact on cell motility. The successful photoconversion of RhB-containing capsules within cells highlights their potential as alternatives to photoconvertible proteins for individual cell labeling, with promising applications in personalized medicine.

Use of Function Diagrams in Physiology Education: Nessie the Nephron and Navigating the Lochs

Function diagrams focus on physiological concepts rather than associated structures and can serve as elaboration tools and mnemonic aids. A function diagram prototype of the gastrointestinal system was recently described (Wilson & Barrett, Adv Physiol Educ, 45:264–268, 2021). Currently, a functional diagram of the glomerulus, nephron, urinary system, and bladder is proposed. Colloquially named “Nessie the Nephron” to loosely capture the looping structure and illusive understanding of renal blood flow, glomerular filtration, and epithelial transport for the student, not to mention the nearly mythical countercurrent multiplier. “Navigating the Lochs” references Nessie’s possible habitat and more importantly the movement and storage of the modified ultrafiltrate from the nephron. The primary analogies that form the structure of this function diagram are: Rain Barrel, Soaker Hose, & Hose Nozzle (afferent and efferent blood flow and filtration pressure); Water Purification System (glomerular filtration barrier forming multiple step filtration process involving the capillary, basement membrane, and podocytes); Mixed Recycling Machine (proximal tubule individual, co-, and bulk transport); Desiccator & Briner (thin descending limb removal of water and thin/thick ascending limb movement of salt); Conveyor Belt Picker (distal nephron selective ion transport); and Concentrator (collecting duct water and urea transport). The primary analogies that elaborate “Navigating the Lochs” are Aqueduct & Cistern System (fluid movement and collection); and Pressure Gauge, Syringe Bulb, and Two-valve Plumbing (bladder storage and micturition). Complimenting these analogies is the rich potential for inclusion of clinical and comparative applications and examples to link previous knowledge and strengthen memories for future retrieval. University of Kentucky College of Medicine. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Efficient estimation of crystal filterability using the discrete element method and the Kozeny-Carman equation

A new method is proposed for efficiently predicting filter cake resistance as a function of crystal size distribution. The method is useful for the preliminary design of processes where an economic tradeoff is encountered between a crystallization step and a filtration step. In that case it is necessary to estimate the filter cake resistance repeatedly as a function of crystal size distribution for the process design and optimization. The method is faster than CFD-DEM and more precise than the random packing assumption. The proposed method is validated using published experimental data. To demonstrate the proposed method, an integrated crystallization-filtration process of ammonium alum is simulated and analyzed. The results show that by increasing the residence time of ammonium alum crystals in the crystallizer from 15 min to 60 min, the crystal cake resistance can be reduced by 42% and the filter area can be reduced by 23%.

Development and Application of a High-Throughput Method for the Purification and Analysis of Surface Carbohydrates from Klebsiella pneumoniae.

Klebsiella pneumoniae (Kp) is a Gram-negative bacterium, and a leading cause of neonatal sepsis in low- and middle-income countries, often associated with anti-microbial resistance. Two types of polysaccharides are expressed on the Kp cell surface and have been proposed as key antigens for vaccine design: capsular polysaccharides (known as K-antigens, K-Ags) and O-antigens (O-Ags). Historically, Kp has been classified using capsule serotyping and although 186 distinct genotypes have been predicted so far based on sequence analysis, many structures are still unknown. In contrast, only 11 distinct OAg serotypes have been described. The characterization of emerging strains requires the development of a high-throughput purification method to obtain sufficient K- and O-Ag material to characterize the large collection of serotypes and gain insight on structural features and potential cross-reactivity that could allow vaccine simplification. Here, this was achieved by adapting our established method for the simple purification of O-Ags, using mild acetic acid hydrolysis performed directly on bacterial cells, followed by filtration and precipitation steps. The method was successfully applied to purify the surface carbohydrates from different Kp strains, thereby demonstrating the robustness and general applicability of the purification method developed. Further, antigen characterization showed that the purification method had no impact on the structural integrity of the polysaccharides and preserved labile substituents such as O-acetyl and pyruvyl groups. This method can be further optimized for scaling up and manufacturing to support the development of high-valency saccharide-based vaccines against Kp.

The removal of pathogenic bacteria and dissolved organic matter from freshwater using microporous membranes: insights into biofilm formation and fouling reversibility

Pathogenic bacteria in drinking-water pose a health risk to consumers, as they compromise the quality of portable water. Chemical disinfection of water containing dissolved organic matter (DOM) causes harmful disinfection by-products. In this work, 4-hydroxybenzoic acid (4-HBA) blended polyethersulfone membranes were fabricated and characterised using microscopic and spectroscopic techniques. The membranes were evaluated for the removal of bacteria and DOM from synthetic and environmental water. Permeate flux increased from 287.30 to 374.60 l m−2 h−1 at 3 bars when 4-HBA increased from 0 to 1.5 wt.%, suggesting that 4-HBA influenced the membrane’s affinity for water. Furthermore, 4-HBA demonstrated antimicrobial properties by inhibiting bacterial growth. The membrane with 1 wt.% 4-HBA recorded 99.4 and 100% bacteria removal in synthetic and environmental water, respectively. Additionally, DOM removal of 55–73% was achieved. A flux recovery ratio (FRR) of 94.6% was obtained when a mixture of bacteria and humic acid was filtered, implying better fouling layer reversibility during cleaning. Furthermore, 100% FRR was achieved when a multimedia granular filtration step was installed prior to membrane filtration. The results illustrated that the membranes had a high permeate flux with low irreversible fouling. This indicated the potential of the membranes in treating complex feed streams using simple cleaning protocols.

A novel method for the establishment of autologous skin cell suspensions: characterisation of cellular sub-populations, epidermal stem cell content and wound response-enhancing biological properties.

Introduction: Autologous cell suspension (ACS)-based therapy represents a highly promising approach for burns and chronic wounds. However, existing technologies have not achieved the desired clinical success due to several limitations. To overcome practical and cost-associated obstacles of existing ACS methods, we have established a novel methodology for rapid, enzymatic disaggregation of human skin cells and their isolation using a procedure that requires no specialist laboratory instrumentation and is performed at room temperature. Methods: Cells were isolated using enzymatic disaggregation of split-thickness human skin followed by several filtration steps for isolation of cell populations, and cell viability was determined. Individual population recovery was confirmed in appropriate culture medium types, and the presence of epidermal stem cells (EpSCs) within keratinocyte sub-populations was defined by flow cytometry via detection of CD49 and CD71. Positive mediators of wound healing secreted by ACS-derived cultures established on a collagen-based wound-bed mimic were detected by proteome arrays and quantified by ELISA, and the role of such mediators was determined by cell proliferation assays. The effect of ACS-derived conditioned-medium on myofibroblasts was investigated using an in-vitro model of myofibroblast differentiation via detection of α-SMA using immunoblotting and immunofluorescence microscopy. Results: Our methodology permitted efficient recovery of keratinocytes, fibroblasts and melanocytes, which remained viable upon long-term culture. ACS-derivatives comprised sub-populations with the CD49-high/CD71-low expression profile known to demarcate EpSCs. Via secretion of mitogenic factors and wound healing-enhancing mediators, the ACS secretome accelerated keratinocyte proliferation and markedly curtailed cytodifferentiation of myofibroblasts, the latter being key mediators of fibrosis and scarring. Discussion: The systematic characterisation of the cell types within our ACS isolates provided evidence for their superior cell viability and the presence of EpSCs that are critical drivers of wound healing. We defined the biological properties of ACS-derived keratinocytes, which include ability to secrete positive mediators of wound healing as well as suppression of myofibroblast cytodifferentiation. Thus, our study provides several lines of evidence that the established ACS isolates comprise highly-viable cell populations which can physically support wound healing and possess biological properties that have the potential to enhance not only the speed but also the quality of wound healing.

Modeling scalability of impurity precipitation in downstream biomanufacturing.

Precipitation during the viral inactivation, neutralization and depth filtration step of a monoclonal antibody (mAb) purification process can provide quantifiable and potentially significant impurity reduction. However, robust commercial implementation of this unit operation is limited due to the lack of a representative scale-down model to characterize the removal of impurities. The objective of this work is to compare isoelectric impurity precipitation behavior for a monoclonal antibody product across scales, from benchtop to pilot manufacturing. Scaling parameters such as agitation and vessel geometry were investigated, with the precipitate amount and particle size distribution (PSD) characterized via turbidity and flow imaging microscopy. Qualitative analysis of the data shows that maintaining a consistent energy dissipation rate (EDR) could be used for approximate scaling of vessel geometry and agitator speeds in the absence of more detailed simulation. For a more rigorous approach, however, agitation was simulated via computational fluid dynamics (CFD) and these results were applied alongside a population balance model to simulate the trajectory of the size distribution of precipitate. CFD results were analyzed within a framework of a two-compartment mixing model comprising regions of high- and low-energy agitation, with material exchange between the two. Rate terms accounting for particle formation, growth and breakage within each region were defined, accounting for dependence on turbulence. This bifurcated model was successful in capturing the variability in particle sizes over time across scales. Such an approach enhances the mechanistic understanding of impurity precipitation and provides additional tools for model-assisted prediction for process scaling.

BONE MARROW MESENCHYMAL STROMAL CELL-DERIVED EXOSOMAL NRF2 AMELIORATES CEREBRAL ISCHEMIA-REPERFUSION INJURY BY TRANSCRIPTIONALLY ACTIVATING LIN28A.

Background: Cerebral ischemia-reperfusion (I/R) injury (CIRI) have severe consequences on brain function, and the exciting evidence has revealed protective role of acyl-CoA synthetase long chain family member 4 (Lin28a) against cerebral ischemia-reperfusion injury. The present work aims to reveal its molecular mechanism in regulating CIRI, with the hope of providing a therapeutic method for cerebral I/R injury. We hypothesized that the exosomal nuclear factor erythroid 2-related factor 2 (NRF2) derived from bone marrow mesenchymal stromal cells could transcriptionally activate Lin28a and thereby alleviate cerebral ischemia-reperfusion injury. This hypothesis was validated in the present work. Methods: Middle cerebral artery occlusion (MCAO) model was established using C57BL/6J mice, and the neurological deficit, infarct volume, and brain water content were assessed to evaluate neuron injury. Human glioblastoma cells (A172) were subjected to oxygen-glucose deprivation and reoxygenation (OGD/R) treatment to mimic a cerebral I/R injury cell model. Exosome isolation reagent was used to isolate exosomes from cell supernatant of bone marrow mesenchymal stromal cells through sequential centrifugation and filtration steps. mRNA expression level of Lin28a was detected by quantitative real-time polymerase chain reaction. Protein expression was analyzed by western blotting assay. TUNEL cell apoptosis detection kit was used to analyze cell apoptosis in brain tissues. Enzyme-linked immunosorbent assays and commercial kits were used to detect levels of inflammatory markers and oxidative stress markers. Ferrous Iron Colorimetric Assay Kit and Fe 2+ colorimetric assay kit were used to analyze Fe 2+ level. The association of Lin28a and NRF2 was identified by chromatin immunoprecipitation assay and dual-luciferase reporter assay. Results: The treatment of MCAO substantially augmented infarct volume in mice, impaired neurological function, and elevated brain water content. Lin28a was lowly expressed in brain tissues of mice with CIRI, and its overexpression protected against cerebral I/R injury of MCAO mice. Moreover, Lin28a overexpression protected A172 cells against OGD/R treatment-induced injury. Additionally, NRF2 transcriptionally activated Lin28a in A172 cells. Bone marrow mesenchymal stromal cell-derived exosomes increased Lin28a expression in a NRF2-dependent manner. Bone marrow mesenchymal stromal cell-derived exosomal NRF2 improved OGD/R-induced A172 cell injury by inducing Lin28a production. Conclusion: Bone marrow mesenchymal stromal cell-derived exosomal NRF2 improved CIRI by transcriptionally activating Lin28a.

Solar-Assisted Green Synthesis, Molecular Docking, Antibacterial, and Cytotoxicity Studies of Symmetrical N, N’-Alkylidene Bisamides Bearing Lower E-Factors

N, N'-alkylidene bisamides show promise in biological and pharmaceutical uses. Advanced chemistry now explores cleaner and more environmentally friendly methods. One such method involves using concentrated solar radiation (CSR) to facilitate the green synthesis of N, N'-alkylidene bisamides. This approach simplifies the process by combining aldehydes and amides in a one-pot reaction. Its solvent-free nature sets it apart, aligning with environmentally friendly practices. Any regular catalyst aids the response, making it efficient. The simplicity continues with an easy filtration step to isolate the products. Notably, there's no need for column chromatography, making the purification process straightforward. In general, a mixture of aldehyde, aryl/alkylamide was taken in a round bottom flask. The reaction mass in RBF was then kept under the concentrated solar radiation (CSR) setup with continuous stirring on a magnetic stirrer. After few hours of stirring the precipitate was observed. After completion of the reaction, the precipitated product was washed with water and recrystallized from hot ethanol to afford pure product symmetrical N, N'-alkylidene bisamide. Dimethyl sulfoxide (DMSO) was used as a solvent to prepare a stock of derivatives. Luria Bertani broth (LB) used for the present study viz; Staphylococ-cus aureus MCC 2408, Escherichia coli MCC 2412, Pseudomonas aeruginosa MCC 2080 and Klebsiella pneumoniae MCC 2451 used to evaluate the antibacterial property of the derivatives. Indeed, this method offers an eco-friendly solution and showcases the potential of using renewable energy sources in chemical synthesis. It is a significant step towards sustainable practices in chemistry, particularly in producing complex organic compounds for biological and pharmaceutical purposes.

High yield sterile filtration process for highly concentrated lentiviral vectors.

The development and manufacture of biopharmaceuticals are subject to strict regulations that specify the required minimum quality of the products. A key measure to meet these quality requirements is the integration of a sterile filtration step into the commercial manufacturing process. Whereas common procedures for most biologics exist, this is challenging for lentiviral vector (LVV) production for ex vivo gene therapy. LVVs nominal size is more than half the pore size (0.2µm) of filters used for sterile filtration. Hence, highly concentrated virus solutions are prone to filter clogging if aggregation of viruses occurs or impurities attach to the viruses. Several filters were screened aiming to identify those which allow filtering highly concentrated stocks of LVVs of up to 1E+9 transducing unitsmL-1 , which corresponds to 4.5E+12 particlesmL-1 . In addition, the effect of endonuclease treatment upstream of the purification process on filter performance was studied. In summary, three suitable filters were identified in a small-scale study (<15mL) with virus yields >80% and the process was successfully scaled-up to a final scale of 100mL LVV stock solution.

Hybrid functional membranes through layer-by-layer assembly of Ti3C2Tx MXene and gelatin-stabilized calcium phosphate nanospheres

MXene-based membranes exhibit promising properties for various applications; however, pure MXene membranes lack sufficient environmental stability and mechanical strength. This work demonstrates that incorporating gelatin-stabilized amorphous calcium phosphate (Gel-ACP) nanospheres into MXene membranes via layer-by-layer assembly significantly enhances flexibility and mechanical strength while retaining electrical conductivity. A pressure-assisted stacking technique was introduced to efficiently fabricate membranes with tunable thickness not achievable through single filtration steps. The Gel-ACP nanospheres, synthesized by co-precipitation of calcium phosphate within gelatin solution, provided a ductile and cytocompatible reinforcement that augmented the properties of the MXene matrix. Direct mixing of the components led to particle aggregation and non-uniform dispersion. In contrast, controlled layer-by-layer nanostructuring maintained membrane conductivity around 102 Scm−1 while dramatically improving mechanical integrity. The optimized hybrid membranes exhibited specific electromagnetic shielding effectiveness of ∼21,000 dBcm2g−1 and withstood over 90 kPa vacuum pressure without rupture, six times higher than pure MXene membranes. Cytocompatibility was confirmed by the proliferation of human mesenchymal stem cells on the membranes. Moreover, the layered membrane exhibited excellent adhesion to bone-mimicking structures, indicating potential utility for bone tissue engineering. Overall, this work provides new design principles for engineering hybrid membranes through controlled multicomponent assembly to overcome intrinsic limitations and impart multifunctionality.

Where have all the polyphenols gone? Check your filter!

Wine represents a complex matrix of polyphenolic compounds. Polyphenols alter the sensory qualities of the wine, represent chemotaxonomic markers and are responsible for many of its health benefits. It is critical to accurately quantify these compounds, which are the subject of extensive current research. Quantification usually requires HPLC analysis, where the main step in sample preparation involves filtration. With the assumption that sample compounds remain on the syringe filter, this study investigated whether diluting the sample before filtration would enable a better recovery of polyphenols, yielding more accurate results. For this purpose, a red, rosé and white wine were diluted with 4 different solvents (water, methanol, ethanol and a 1:1 methanol-ethanol mixture) prior to filtration, and their polyphenolic composition was analyzed. Only 7 polyphenols present in low concentrations were not affected by dilution, while 38 compounds were all detected in higher concentrations when applying certain solvents, compared to undiluted wine. The methanol-ethanol mixture enabled the best flow of polyphenolics through the filter, while the water dilution showed that 30–40% of the sum of anthocyanins remained on the filter if a dilution step was not included in the sample preparation procedure. This study confirmed the need to incorporate a preliminary evaluation of the filtration step during sample preparation to improve the accuracy of subsequent HPLC analyses.

Optimization of synthesis conditions and calibration of water-swellable polyacrylamide microgels

Precipitation Polymerization (PP) and Inverse Emulsion Polymerization (IEP) are the main procedures widely used for the synthesis of microgels from acrylamide derivate monomers, in both academic and industrial spheres. Here, these procedures were optimized for pure acrylamide monomer to synthetize a “model” polyacrylamide microgel targeting a minimized size of approximately 200 nm in radius. For this neutral and non-responsive monomer, the role of the co-solvent in PP and co-surfactant in IEP was discussed. This work demonstrates the crucial step of purification and calibration on microgels physical properties in suspension. In particular, the filtration step has a significant impact on their rheological behaviour, where the flow properties requiring a complex description become analysable with a standard Carreau–Yasuda model. In summary, this paper provides a systematic discussion on the role of each step in the elaboration of model microgel, as a routine checklist to be considered before further physical-chemical studies.

Elimination microplastic particles in brine process water for ensuring the safety of brined cabbage

Various studies have investigated the presence of microplastics (MPs) in food and their potential hazardous impact on human health. The frequency of human exposure to MPs, particularly through the consumption of manufactured food and drinking water, is increasing. However, data regarding MP contamination in brine and brined cabbage used for the production of kimchi are limited. Here, we quantified MPs in brine process water during the production of brined cabbage. Pretreatment of the brine process water by performing a filtration step resulted in an MP-removal efficiency of 98.7–100%; 3671 ± 174 MP particles were observed in brining process water that was not filtered. A glass filter, STS filter, and Si Filter showed significant MP-removal efficiency, decreasing the number of MP particles in brining process water to 2,361, 2,775, and 3,490, respectively (p < 0.05). Our results provide data on how filtering of brine can effectively safeguard kimchi from MP contamination and e can be produced. However, to overcome the limitations of our laboratory-scale study, additional technologies should be used in the future for large-scale filtration processes.

Optimization of the filtration and centrifugation steps for the isolation of exosome-like nanoparticles (ELNs) from grapes

ABSTRACT Exosome-like nanoparticles (ELNs) are a class of nanosized extracellular vesicles from plants that can deliver drugs, siRNA, DNA, and proteins to various types of cells. Purification of ELNs from plants are tricky when compared to that from body fluids or cell culture medium because the initial suspension of the former contains high amounts of sugar, fiber, fat, etc. In this study, we have optimized the different steps for the isolation of ELNs from grapes. After preparing the juice, the bulk density was measured by Brix analysis and followed the same bulk density whenever doing the isolation. Differential centrifugation at various speeds and times and membrane filtration using different pore-size membranes were also optimized before the final step of ELN separation by ultracentrifugation. The size, zeta potential, and PDI value of the isolated ELNs were measured using a Malvern Zeta Sizer. SEM analysis showed that the grape ELN has an average size of 140.8 ± 10.75 nm. The results indicated that filtration and centrifugation at different levels are essential before the ultracentrifugation for isolating homogenous grape ELNs with desired size, zeta potential and PDI value. From the optimized method, we have obtained 4.8 ± 0.509 mg protein equivalents of ELNs from 100 g of grapes.

A probabilistic forecast methodology for volatile electricity prices in the Australian National Electricity Market

The South Australia region of the Australian National Electricity Market (NEM) displays some of the highest levels of price volatility observed in modern electricity markets. This paper outlines an approach to probabilistic forecasting under these extreme conditions, including spike filtration and several post-processing steps. We propose using quantile regression as an ensemble tool for probabilistic forecasting, with our combined forecasts achieving superior results compared to all constituent models. Within our ensemble framework, we demonstrate that averaging models with varying training-length periods leads to a more adaptive model and increased prediction accuracy. The applicability of the final model is evaluated by comparing our median forecasts with the point forecasts available from the Australian NEM operator, with our model outperforming these NEM forecasts by a significant margin.

Purification of Borrelia burgdorferi Outer Membrane Vesicles.

Bacterial outer membrane vesicles (OMVs) are spherical membrane constructs shed by gram-negative bacteria. OMVs produced by the Lyme disease pathogen Borrelia burgdorferi have been identified to contain such virulence factors as OspA, OspB, OspC, and genetic material. However, the function and possible pathogenicity of borrelial OMVs are still undetermined. Therefore, further research on borrelial OMVs is required, and for that a standard method for OMV purification is necessary. Here we describe a successful and reproducible purification of borrelial outer membrane vesicles using concentration, filtration, and ultracentrifugation steps.