scholarly journals IMINATION OF CHITOSAN NANOFIBERS IN A HETEROGENEOUS SYSTEM. SYNTHESIS OPTIMIZATION AND IMPACT ON FIBER MORPHOLOGY

2021 ◽  
Vol 55 (7-8) ◽  
pp. 785-793
Author(s):  
ALEXANDRU ANISIEI ◽  
ANDRA-CRISTINA BOSTANARU ◽  
MIHAI MARES ◽  
LUMINITA MARIN
Keyword(s):  
Polyethylene Glycol ◽  
Liquid Phase ◽  
Polar Solvent ◽  
Solid Phase ◽  
Fiber Morphology ◽  
Glycol Chitosan ◽  
Fibrous Morphology ◽  
Phase Systems ◽  
The Impact ◽  
Heterogenous System

The paper aimed to prepare imino-chitosan fibers by the imination reaction in a heterogenous system, targeting the improvement of anti-pathogenic activity. To this end, porous neat chitosan fibers were prepared by electrospinning of the polyethylene glycol/chitosan blend, followed by polyethylene glycol removal. Imination of the neat chitosan fibers was carried out in three liquid phase systems using solvents of different polarity and, consequently, different ability to swell the solid phase chitosan fibers. The successful imination was qualitatively and quantitatively assessed by FTIR and 1H-NMR spectroscopy, and the impact of the liquid phase on the fibers’ morphology was evaluated by SEM, POM and AFM microscopy. Further, the antimicrobial activity of the imino-chitosan fibers was investigated on relevant bacterial and fungal strains. It was concluded that the prior swelling in water of the fibers improved the imination degree, while the use of a less polar solvent, such as toluene, favored the preservation of the fibrous morphology. The imination with an antimicrobial aldehyde endowed the chitosan fibers with the ability to create a physical barrier against pathogens.

scholarly journals LIQUID PHASE CHROMATOGRAPHIC METHODS APPLIED TO DETERMINE EMERGING CONTAMINANTS IN ENVIRONMENTAL SAMPLES

2020 ◽  
Vol 2 (1) ◽  
pp. 11-20
Author(s):  
Vasile Ion Iancu ◽  
Jana Petre ◽  
Toma Galaon ◽  
Gabriel Valentin Serban ◽  
Marcela Niculescu ◽  
...  
Keyword(s):  
Surface Water ◽  
Liquid Phase ◽  
Environmental Samples ◽  
Flame Retardants ◽  
Emerging Contaminants ◽  
Municipal Wastewater ◽  
Solid Phase ◽  
Endocrine Disrupting Chemicals ◽  
Municipal Wastewater Treatment ◽  
The Impact

Emerging contaminants are a heterogeneous group of chemicals that include daily personal care products and pharmaceuticals (PPCPs), flame retardants, endocrine-disrupting chemicals (EDCs) and nanoparticles (NPs) present in environment which are unregulated. In this review, we present the methods of analysis conducted by INCD-ECOIND regarding some classes of emerging contaminants (neonicotinoid pesticides, beta-blocker drugs) that are not regulated by the legislation, in different types of environmental samples (wastewater, surface water). The present review presents the selective solid-phase extraction (SPE) methods used for isolation of the targeted compounds from aqueous matrices and also the main instrumental parameters of the separation and detection process. After extraction, the compounds were subjected to liquid phase chromatographic separation with mass spectrometric detection (UHPLC-MS/MS). Finally, the methods were applied in the determination of compounds from different categories of water, carrying out studies on the efficiency of elimination of compounds in several municipal wastewater treatment plants (WWTPs). In addition, the impact of the treatment plants on some receiving surface water used to obtain drinking water was studied.

scholarly journals Excess Li2O Additives to Promote Grain Boundary Growth and Improve Ionic Conductivity of LiTa2PO8 Solid Electrolytes

2021 ◽  
Vol 8 ◽  
Author(s):  
Qian Zhang ◽  
Fuhai Meng ◽  
Ruixiong Liao ◽  
Long Chen ◽  
Mengqian Xu ◽  
...  
Keyword(s):  
Solid State ◽  
Liquid Phase ◽  
Ionic Conductivity ◽  
Grain Boundary ◽  
Solid Phase ◽  
Synthesis Method ◽  
Lithium Ion ◽  
Liquid Phase Sintering ◽  
Diffusion Activation Energy ◽  
The Impact

LiTa2PO8 (LTPO) is a new solid-state lithium ion electrolyte material reported in the latest research, which has high bulk ionic conductivity and low grain boundary ion conductivity. However, it is difficult to density with conventional sintering methods. Herein, in this work, the solid-phase synthesis method was used to prepared the LTPO solid-state electrolyte, and the influence of the amount of lithium on the structure and performance of LTPO electrolyte material was investigated. The results show that the excess Li2O does not increase other impurities and does not change the structure of the material, but the liquid phase produced by the excess Li2O can promote the elimination of interfacial pores, accelerate the direct bonding of grains and improve the ionic conductivity of grain boundary, thus improving the overall ionic conductivity of the material. Considering the volatilization of lithium and the impact of liquid phase sintering at high temperatures and the content restructuring, after adding 20 wt% excess formulation of Li2O, the resultant of LTPO density is 5.0 g/cm3, the density reaches 85.58%. As a result, the total ionic conductivity of the electrolyte is 3.28 × 10–4 S/cm at 25°C, and the Li-ion diffusion activation energy is 0.27 eV. In addition, after loading this electrolyte into a Li–Li symmetric battery, it is proved that the electrolyte has lithium ion transport performance and can be used in all-solid-state batteries. However, it is also found from cyclic voltammetry (CV) and X-ray photoelectron spectroscopy (XPS) analysis that the interface between LTPO material and Li is unstable, and Ta5+ ions are reduced, which will be another key issue to be addressed in the future.

Phase Separation Dynamics in Oil–Polyethylene Glycol–Sulfate–Water Based Three-Liquid-Phase Systems

2015 ◽  
Vol 54 (15) ◽  
pp. 3952-3960 ◽  
Author(s):  
Jieyuan Lin ◽  
Kun Huang ◽  
Zhicheng Suo ◽  
Xiaopei Li ◽  
Chuanxu Xiao ◽  
...  
Keyword(s):  
Phase Separation ◽  
Polyethylene Glycol ◽  
Liquid Phase ◽  
Water Based ◽  
Phase Systems

Immobilization of immunoglobulins onto surface-treated and untreated polystyrene beads for radioimmunoassays

1990 ◽  
Vol 36 (3) ◽  
pp. 492-496 ◽  
Author(s):  
S E Kakabakos ◽  
E Livanlou ◽  
G P Evangelatos ◽  
D S Ithakissios
Keyword(s):  
Polyethylene Glycol ◽  
Liquid Phase ◽  
Bovine Serum Albumin ◽  
Bovine Serum ◽  
Solid Phase ◽  
Acidic Ph ◽  
Bovine Serum Albumin Solution ◽  
Albumin Solution ◽  
Polystyrene Beads ◽  
Optimum Ph

Abstract The immunoreactivity of anti-triiodothyronine (anti-T3) IgG, pretreated at acidic pH and adsorbed onto polystyrene beads, was significantly greater than that determined for native anti-T3 IgG immobilized at optimum pH 3.5. Acidic-pH-pretreated IgG, adsorbed at pH 7.0 onto ethanol-treated beads, had less immunoreactivity than that on untreated beads and gave values similar to those of native IgG adsorbed onto activated beads at pH 9.6. The rate of immobilization onto treated beads was significantly greater than onto untreated ones, and the binding was reproducible (intra- and inter-batch coating CV, 3.7-4.6% and 7.2%, respectively) and very resistant to successive washings. A post-washing incubation in 10 mg/L bovine serum albumin solution was required to eliminate the decreased immobilized immunoreactivity caused by some washing reagents. For solid-phase radioimmunoassays of T3, 40% less antibody was needed when acidic-pH-pretreated IgG was adsorbed onto untreated beads or when native IgG was adsorbed onto ethanol-treated beads, in comparison with native IgG adsorbed onto untreated beads. Results and assay characteristics with such beads were comparable with results for solid-phase and liquid-phase polyethylene glycol assay of T3.

Identification of hepatitis a virus in cell cultures by solid phase immune electron microscopy

1986 ◽  
Vol 44 ◽  
pp. 238-239
Author(s):  
C.D. Humphrey ◽  
T.L. Cromeans ◽  
E.H. Cook ◽  
D.W. Bradley
Keyword(s):  
Electron Microscopy ◽  
Liquid Phase ◽  
Cell Cultures ◽  
Rapid Detection ◽  
Hepatitis A ◽  
Hepatitis A Virus ◽  
Solid Phase ◽  
Immune Electron Microscopy ◽  
Detection And Identification

There is a variety of methods available for the rapid detection and identification of viruses by electron microscopy as described in several reviews. The predominant techniques are classified as direct electron microscopy (DEM), immune electron microscopy (IEM), liquid phase immune electron microscopy (LPIEM) and solid phase immune electron microscopy (SPIEM). Each technique has inherent strengths and weaknesses. However, in recent years, the most progress for identifying viruses has been realized by the utilization of SPIEM.

SYNTHESIS OF HYDROGEN IN ACOUSTOPLASMA DISCHARGE IN A LIQUID-PHASE STREAM

2019 ◽  
pp. 42-48 ◽  
Author(s):  
N. A. Bulychev
Keyword(s):  
Liquid Phase ◽  
Organic Compounds ◽  
Electrode Materials ◽  
Solid Phase ◽  
Plasma Discharge ◽  
Raw Material ◽  
Two Phase ◽  
Reduced Pressure ◽  
External Power Source ◽  
Phase Medium

In this paper, the plasma discharge in a high-pressure fluid stream in order to produce gaseous hydrogen was studied. Methods and equipment have been developed for the excitation of a plasma discharge in a stream of liquid medium. The fluid flow under excessive pressure is directed to a hydrodynamic emitter located at the reactor inlet where a supersonic two-phase vapor-liquid flow under reduced pressure is formed in the liquid due to the pressure drop and decrease in the flow enthalpy. Electrodes are located in the reactor where an electric field is created using an external power source (the strength of the field exceeds the breakdown threshold of this two-phase medium) leading to theinitiation of a low-temperature glow quasi-stationary plasma discharge.A theoretical estimation of the parameters of this type of discharge has been carried out. It is shown that the lowtemperature plasma initiated under the flow conditions of a liquid-phase medium in the discharge gap between the electrodes can effectively decompose the hydrogen-containing molecules of organic compounds in a liquid with the formation of gaseous products where the content of hydrogen is more than 90%. In the process simulation, theoretical calculations of the voltage and discharge current were also made which are in good agreement with the experimental data. The reaction unit used in the experiments was of a volume of 50 ml and reaction capacity appeared to be about 1.5 liters of hydrogen per minute when using a mixture of oxygen-containing organic compounds as a raw material. During their decomposition in plasma, solid-phase products are also formed in insignificant amounts: carbon nanoparticles and oxide nanoparticles of discharge electrode materials.

The Impact of Bioconjugation on the Interfacial Activity of a Protein Biosurfactant

2018 ◽  
Author(s):  
Hossam H Tayeb ◽  
Marina Stienecker ◽  
Anton Middelberg ◽  
Frank Sainsbury
Keyword(s):  
Polyethylene Glycol ◽  
Colloidal Stability ◽  
Point Mutations ◽  
Pharmaceutical Formulations ◽  
Industrial Processes ◽  
Parent Molecule ◽  
Site Specific ◽  
Interfacial Activity ◽  
Surface Active ◽  
The Impact

Biosurfactants, are surface active molecules that can be produced by renewable, industrially scalable biologic processes. DAMP4, a designer biosurfactant, enables the modification of interfaces via genetic or chemical fusion to functional moieties. However, bioconjugation of addressable amines introduces heterogeneity that limits the precision of functionalization as well as the resolution of interfacial characterization. Here we designed DAMP4 variants with cysteine point mutations to allow for site-specific bioconjugation. The DAMP4 variants were shown to retain the structural stability and interfacial activity characteristic of the parent molecule, while permitting efficient and specific conjugation of polyethylene glycol (PEG). PEGylation results in a considerable reduction on the interfacial activity of both single and double mutants. Comparison of conjugates with one or two conjugation sites shows that both the number of conjugates as well as the mass of conjugated material impacts the interfacial activity of DAMP4. As a result, the ability of DAMP4 variants with multiple PEG conjugates to impart colloidal stability on peptide-stabilized emulsions is reduced. We suggest that this is due to constraints on the structure of amphiphilic helices at the interface. Specific and efficient bioconjugation permits the exploration and investigation of the interfacial properties of designer protein biosurfactants with molecular precision. Our findings should therefore inform the design and modification of biosurfactants for their increasing use in industrial processes, and nutritional and pharmaceutical formulations.

Development of Strategies for Glycopeptide Synthesis: An Overview on the Glycosidic Linkage

2020 ◽  
Vol 24 (21) ◽  
pp. 2475-2497
Author(s):  
Andrea Verónica Rodríguez-Mayor ◽  
German Jesid Peralta-Camacho ◽  
Karen Johanna Cárdenas-Martínez ◽  
Javier Eduardo García-Castañeda
Keyword(s):  
Chemical Synthesis ◽  
Solid Phase ◽  
Building Blocks ◽  
Heterogeneous Environments ◽  
Phase Synthesis ◽  
Low Concentrations ◽  
Biological Sources ◽  
Synthetic Routes ◽  
The Impact ◽  
Potential Use

Glycoproteins and glycopeptides are an interesting focus of research, because of their potential use as therapeutic agents, since they are related to carbohydrate-carbohydrate, carbohydrate-protein, and carbohydrate-lipid interactions, which are commonly involved in biological processes. It has been established that natural glycoconjugates could be an important source of templates for the design and development of molecules with therapeutic applications. However, isolating large quantities of glycoconjugates from biological sources with the required purity is extremely complex, because these molecules are found in heterogeneous environments and in very low concentrations. As an alternative to solving this problem, the chemical synthesis of glycoconjugates has been developed. In this context, several methods for the synthesis of glycopeptides in solution and/or solid-phase have been reported. In most of these methods, glycosylated amino acid derivatives are used as building blocks for both solution and solid-phase synthesis. The synthetic viability of glycoconjugates is a critical parameter for allowing their use as drugs to mitigate the impact of microbial resistance and/or cancer. However, the chemical synthesis of glycoconjugates is a challenge, because these molecules possess multiple reaction sites and have a very specific stereochemistry. Therefore, it is necessary to design and implement synthetic routes, which may involve various protection schemes but can be stereoselective, environmentally friendly, and high-yielding. This review focuses on glycopeptide synthesis by recapitulating the progress made over the last 15 years.

Introduction to geomicrobiology

2018 ◽  
Author(s):  
David L. Kirchman
Keyword(s):  
Fossil Fuels ◽  
Solid Phase ◽  
Direct Reduction ◽  
Iron Oxidation ◽  
Mineral Dissolution ◽  
Precipitation Process ◽  
Soluble Ions ◽  
Chemolithoautotrophic Bacteria ◽  
The Impact

Geomicrobiology, the marriage of geology and microbiology, is about the impact of microbes on Earth materials in terrestrial systems and sediments. Many geomicrobiological processes occur over long timescales. Even the slow growth and low activity of microbes, however, have big effects when added up over millennia. After reviewing the basics of bacteria–surface interactions, the chapter moves on to discussing biomineralization, which is the microbially mediated formation of solid minerals from soluble ions. The role of microbes can vary from merely providing passive surfaces for mineral formation, to active control of the entire precipitation process. The formation of carbonate-containing minerals by coccolithophorids and other marine organisms is especially important because of the role of these minerals in the carbon cycle. Iron minerals can be formed by chemolithoautotrophic bacteria, which gain a small amount of energy from iron oxidation. Similarly, manganese-rich minerals are formed during manganese oxidation, although how this reaction benefits microbes is unclear. These minerals and others give geologists and geomicrobiologists clues about early life on Earth. In addition to forming minerals, microbes help to dissolve them, a process called weathering. Microbes contribute to weathering and mineral dissolution through several mechanisms: production of protons (acidity) or hydroxides that dissolve minerals; production of ligands that chelate metals in minerals thereby breaking up the solid phase; and direct reduction of mineral-bound metals to more soluble forms. The chapter ends with some comments about the role of microbes in degrading oil and other fossil fuels.

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