Negative chromatography of hepatitis B virus-like particles: comparative study of different adsorbent designs

Purification of virus-like particles (VLPs) in bind-and-elute mode has reached a bottleneck. Negative chromatography has emerged as the alternative solution; however, benchmark of negative chromatography media and their respective optimized conditions are absent. Hence, this study was carried out to compare the performance of different negative chromatography media for the purification of hepatitis B VLPs (HB-VLPs) from clarified Escherichia coli feedstock. The modified anion exchange media, core-shell adsorbents (InertShell and InertLayer 1000) and polymer grafted adsorbents (SQ) were compared. The results of chromatography from packed bed column of core-shell adsorbents showed that there is a trade-off between the purity and recovery of HB-VLPs in the flowthrough fraction due to the shell thickness. Atomic force microscopic analysis revealed funnel-shaped pore channels in the shell layer which may contribute to the entrapment of HB-VLPs. A longer residence time at a lower feed flow rate (0.5ml/min) improved slightly the HB-VLPs purity in all modified adsorbents, but the recovery in InertShell reduced substantially. The preheat-treatment is not recommended for the negative chromatography as the thermal-induced co-aggregation of HCPs and HB-VLPs would flow along with HB-VLPs and thus reduced the HB-VLPs purity in the flowthrough. Further reduction in the feedstock concentration enhanced the purity of HB-VLPs especially in InertLayer 1000 but reduced substantially the recovery of HB-VLPs. In general, the polymer grafted adsorbent, SQ, performed better than the core-shell adsorbents in handling a higher feedstock concentration

Robust, Conformal ZnO Coatings on Fabrics via Atmospheric-Pressure Spatial Atomic Layer Deposition with In-Situ Thickness Control

This is the peer reviewed version of the following article: Gurbandurdyyev, G., Mistry, K., Delumeau, L. V., Loke, J. Y., Teoh, C. H., Cheon, J., Ye, F., Tam, K. C., & Musselman, K. P. (2023). Robust, conformal zno coatings on fabrics via atmospheric‐pressure spatial atomic layer deposition with in‐situ thickness control**. ChemNanoMat, 9(2)., which has been published in final form at https://doi.org/10.1002/cnma.202200498. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.Zinc oxide (ZnO) is a promising material for functionalization of textiles. It can add a range of functionalities, including UV protection, antimicrobial activity, flame retardancy, hydrophobicity and electrical conductivity. Commercialization of ZnO – coated textiles is still limited due to the cost and challenges related to their manufacture. Moreover, making robust coatings on textiles and measuring their thickness is also challenging. In this work, atmospheric-pressure spatial atomic layer deposition (AP-SALD) systems are utilized for the first time to coat synthetic spun-bond polypropylene (PP) and natural cotton fabrics with ZnO. The coatings are found to be conformal and uniform, forming complete shells around the fabric fibers. The growth rate is measured to be ~0.24 nm/cycle using an in-situ reflectance setup and Virtual Interface (VI) model, which enable precise control of the coating thickness. The coatings are shown to provide UV-protection and render cotton fabric hydrophobic. No damage is observed after washing, linear abrasion, adhesion, twisting and bending tests, indicating that the coatings are robust. Aerosol-penetration tests indicate the coatings do not impact the filtering efficiency of fabrics used in N95 respirators. The results are encouraging for industrialization of the AP-SALD technique for functional textiles.The polypropylene fabrics were provided by Eclipse Automation. The authors thank Joe Paquette and Rob Shwery at Eclipse Automation for providing helpful information about the polypropylene fabrics. K.P.M. acknowledges funding from NSERC Alliance (ALLRP 554383-20), NSERC Discovery (RGPIN-2017-04212, RGPAS-2017-507977), Canada Foundation for Innovation John R. Evans Leaders Fund (Project 35552), Canada Foundation for Innovation Exceptional Opportunities Fund COVID-19 (Project 41017), and Ontario Ministry of Research, Innovation and Science Low Carbon Innovation Fund (Project Perovskite Photovoltaics)

Dijet Resonance Search with Weak Supervision Using root S=13 TeV pp Collisions in the ATLAS Detector

This Letter describes a search for narrowly resonant new physics using a machine-learning anomaly detection procedure that does not rely on signal simulations for developing the analysis selection. Weakly supervised learning is used to train classifiers directly on data to enhance potential signals. The targeted topology is dijet events and the features used for machine learning are the masses of the two jets. The resulting analysis is essentially a three-dimensional search A → BC, for mA ∼ OðTeVÞ, mB; mC ∼ Oð100 GeVÞ and B, C are reconstructed as large-radius jets, without paying a penalty associated with a large trials factor in the scan of the masses of the two jets. The full run 2 ffiffi s p ¼ 13 TeV pp collision dataset of 139 fb−1 recorded by the ATLAS detector at the Large Hadron Collider is used for the search. There is no significant evidence of a localized excess in the dijet invariant mass spectrum between 1.8 and 8.2 TeV. Cross-section limits for narrow-width A, B, and C particles vary with mA, mB, and mC. For example, when mA ¼ 3 TeV and mB ≳ 200 GeV, a production cross section between 1 and 5 fb is excluded at 95% confidence level, depending on mC. For certain masses, these limits are up to 10 times more sensitive than those obtained by the inclusive dijet search. These results are complementary to the dedicated searches for the case that B and C are standard model boson

Novel associative polymers for environmentally friendly coating applications

The main focus of our research was on a class of associating polyelectrolytes that are prepared as latex particles and swell when exposed to a base. A series of Hydrophobic Alkali-Soluble Emulsion (HASE) polymers were prepared by Dow Chemicals (formerly Union Carbide) and studied by the battery of techniques. We have demonstrated the power of combining fluorescence and rheology experiments to study the unique behaviour of these polymer solutions

Applications and characterisation of novel thermal sensitive polymer latexes

78 p.This project is concerned with the experimental investigation of the particle size and flow characteristics of poly(N-isopropylacrylamide), poly(NIPAM) latex system. The effects of temperature, salt (sodium chloride, NaCl), polymer concentration, surfactant on the particle size and rheological properties of poly(NIPAM) were studied.RP 36/9

Study of heat transfer and coating properties in fluidized bed powder coating of metal surfaces

In this project, a comprehensive study of the fluidized bed coating process was carried out using a two-pronged experimental and numerical approach.RG 30/9

Development of high performance polymer blends

Main aim of the project is to develop high performance polymer blends.RG 45/9

Use of isothermal titration calorimetry to study surfactant aggregation in colloidal systems

Background: Isothermal titration calorimetry (ITC) is a general technique that allows for precise and highly sensitive measurements. These measurements may provide a complete and accurate thermodynamic description of association processes in complex systems such as colloidal mixtures. Scope of the review: This review will address uses of ITC for studies of surfactant aggregation to form micelles, with emphasis on the thermodynamic studies of homologous surfactant series. We will also review studies on surfactant association with polymers of different molecular characteristics and with colloidal particles. General significance: ITC studies on the association of different homologous series of surfactants provide quantitative information on independent contribution from their apolar hydrocarbon chains and polar headgroups to the different thermodynamic functions associated with micellization (Gibbs energy, enthalpy and entropy). Studies on surfactant association to polymers by ITC provide a comprehensive description of the association process, including examples in which particular features revealed by ITC were elucidated by using ancillary techniques such as light or X-ray scattering measurements. Examples of uses of ITC to follow surfactant association to biomolecules such as proteins or DNA, or nanoparticles are also highlighted. Finally, recent theoretical models that were proposed to analyze ITC data in terms of binding/association processes are discussed. Major conclusions: This review stresses the importance of using direct calorimetric measurements to obtain and report accurate thermodynamic data, even in complex systems. These data, whenever possible, should be confirmed and associated with other ancillary techniques that allow elucidation of the nature of the transformations detected by calorimetric results, providing a complete description of the process under scrutiny. This article is part of a Special Issue entitled Microcalorimetry in the BioSciences - Principles and Applications, edited by Fadi Bou-Abdallah18605SI9991016CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESsem informaçã

Use Of Isothermal Titration Calorimetry To Study Surfactant Aggregation In Colloidal Systems.

Isothermal titration calorimetry (ITC) is a general technique that allows for precise and highly sensitive measurements. These measurements may provide a complete and accurate thermodynamic description of association processes in complex systems such as colloidal mixtures. This review will address uses of ITC for studies of surfactant aggregation to form micelles, with emphasis on the thermodynamic studies of homologous surfactant series. We will also review studies on surfactant association with polymers of different molecular characteristics and with colloidal particles. ITC studies on the association of different homologous series of surfactants provide quantitative information on independent contribution from their apolar hydrocarbon chains and polar headgroups to the different thermodynamic functions associated with micellization (Gibbs energy, enthalpy and entropy). Studies on surfactant association to polymers by ITC provide a comprehensive description of the association process, including examples in which particular features revealed by ITC were elucidated by using ancillary techniques such as light or X-ray scattering measurements. Examples of uses of ITC to follow surfactant association to biomolecules such as proteins or DNA, or nanoparticles are also highlighted. Finally, recent theoretical models that were proposed to analyze ITC data in terms of binding/association processes are discussed. This review stresses the importance of using direct calorimetric measurements to obtain and report accurate thermodynamic data, even in complex systems. These data, whenever possible, should be confirmed and associated with other ancillary techniques that allow elucidation of the nature of the transformations detected by calorimetric results, providing a complete description of the process under scrutiny. This article is part of a Special Issue entitled Microcalorimetry in the BioSciences - Principles and Applications, edited by Fadi Bou-Abdallah.186