scholarly journals The Chitosan Implementation into Cotton and Polyester/Cotton Blend Fabrics

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1616
Author(s):  
Sandra Flinčec Grgac ◽  
Anita Tarbuk ◽  
Tihana Dekanić ◽  
Witold Sujka ◽  
Zbigniew Draczyński
Keyword(s):  
Antimicrobial Activity ◽  
Antimicrobial Properties ◽  
Mechanical Damage ◽  
Hospital Environment ◽  
Glutaric Aldehyde ◽  
Care Processes ◽  
The Stability ◽  
Hydrolysis Of

Chitosan is an environmentally friendly agent that is used to achieve the antimicrobial properties of textiles. Nowadays, the binding of chitosan to the textiles has been thoroughly researched due to the increasing demands on the stability of achieved properties during the textile care processes. Most crosslinking agents for chitosan are not safe for humans or environment, such as glutaric aldehyde (GA) and formaldehyde derivatives. Eco-friendly polycarboxyilic acids (PCAs) are usually used in after-treatment. In this work, chitosan powder was dissolved in citric acid with sodium hydrophosphite (SHP) as a catalyst. Standard cotton (CO) and polyester/cotton (PES/CO) fabrics were pretreated in 20% NaOH, similar to mercerization, in order to open the structure of the cotton fibers and hydrolyze polyester fibers, continued by finishing in the gelatin chitosan bath. Afterwards, the hot rinsing process, followed by drying and curing, closed the achieved structure. The main objective was to achieve durable antimicrobial properties to multiple maintenance cycles CO and PES/CO fabric in order to apply it in a hospital environment. The characterization of fabrics was performed after treatment, first and fifth washing cycles according ISO 6330:2012 by field emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectroscopy (FTIR-ATR), electrokinetic analysis (EKA), by the determination of tensile properties and mechanical damage (wear), and the antimicrobial activity. The application of 20% NaOH led to the swelling and mercerization of cotton cellulose, and hydrolysis of polyester, resulting in better mechanical properties. It has been confirmed that the chitosan particles were well implemented into the cotton fiber and onto to the polyester component of PES/CO blend. The presence of chitosan was confirmed after five washing cycles, but in lower quantity. However, achieved antimicrobial activity is persistent.

SOME OBSERVATIONS ON THE PANCREATIC AMYLASE AND INTESTINAL MALTASE OF THE CHICK

1963 ◽  
Vol 41 (1) ◽  
pp. 2107-2121 ◽  
Author(s):  
B. M. Laws ◽  
J. H. Moore
Keyword(s):  
Small Intestine ◽  
Amylase Activity ◽  
Pancreatic Amylase ◽  
Ph Optimum ◽  
Modified Method ◽  
Mucosal Cells ◽  
Small Intestinal ◽  
The Stability ◽  
Hydrolysis Of

The digestive enzymes amylase and maltase were studied in acetone-dried powders or homogenates of the pancreatic and small intestinal tissues and small intestinal contents obtained from chicks of various ages. The stability of pancreatic amylase, which was relatively low in 0.15 M sodium chloride, was increased markedly by the presence of 0.02 M barbiturate buffer. The pH optimum of pancreatic amylase (chloride-activated) was 7.0 whereas that of intestinal maltase was 6.9. High levels of pancreatic amylase activity were found in the newly-hatched chick but these levels decreased during the following 20 days and then remained constant. The contrast between the high amylase and low maltase activities in the contents of the small intestine suggested that molecules of maltose, formed by the hydrolysis of starch, were absorbed as such by the mucosal cells. It appeared that maltose could be absorbed with equal facility from all sections of the small intestine of the 10-day-old chick but in the older birds maltose absorption seemed to occur more readily from the upper small intestine than from the duodenum and lower small intestine. A modified method for the determination of maltase activity is described.

Effects of Rhamnolipids on Enzymatic Hydrolysis of Bamboo Biomass and Mechanism

2020 ◽  
Vol 14 (4) ◽  
pp. 453-460
Author(s):  
Ruyi Sha ◽  
Zhan Yu ◽  
Zhenzhen Wang ◽  
Edwin Menledy Gbor ◽  
Ligang Jiang ◽  
...  
Keyword(s):  
Enzymatic Hydrolysis ◽  
Fluorescence Probe ◽  
Economic Losses ◽  
Dilute Acid ◽  
Site Of Action ◽  
The Stability ◽  
Surface Modified ◽  
Hydrolysis Of ◽  
Positive Effect

The lignin present in lignocellulose seriously affects the efficiency of cellulose enzymatic hydrolysis. In addition, lignin adsorbs high-cost cellulase, causing greater economic losses. Lignin can also disturb the site of action of cellulase and reduce the efficiency of hydrolysis. Therefore, if lignin is removed or surface modified before cellulose enzymatic hydrolysis, the enzymatic hydrolysis efficiency of lignocellulosic biomass will be greatly improved. In this paper, the cellulose enzymatic properties of bamboo biomass being treated with dilute acid and alkaline under the intervention of biosurfactant rhamnolipid were evaluated. The effects of rhamnolipids on the adsorption characterization of cellulose on pretreated bamboo were studied. Besides, the inter-communication between rhamnolipids and cellulose was investigated by fluorescence probe. The results showed that rhamnolipids could have a positive effect on the enzymatic hydrolysis of bamboo biomass by reducing the non-productive adsorption of cellulase on the surface of lignocellulose. The outcome illustrated that cellulase could be combined with rhamnolipids micelles, participating in the formation of rhamnolipids micelles, thereby increasing the internal hydrophobicity of the micelles, but could not change the properties of rhamnolipids micelles higher than one CMC (Critical Micelle Concentration). It can be seen that the interaction between rhamnolipids and cellulase is beneficial to enhance the stability and enzymatic activity of cellulase, thereby improving the enzymatic hydrolysis efficiency of cellulose in biomass. Based on these results, a theoretical knowledge about the mechanism of enhancing the enzymatic hydrolysis efficiency of lignocellulose by biosurfactants rhamnolipids is provided.

scholarly journals Synthesis of Copper Nanoparticles Stabilized with Organic Ligands and Their Antimicrobial Properties

Polymers ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2846
Author(s):  
Noemi Jardón-Maximino ◽  
Marissa Pérez-Alvarez ◽  
Gregorio Cadenas-Pliego ◽  
Luis E. Lugo-Uribe ◽  
Christian Cabello-Alvarado ◽  
...  
Keyword(s):  
Copper Nanoparticles ◽  
Chemical Reduction ◽  
Synthesis Method ◽  
Antimicrobial Properties ◽  
Stabilizing Agents ◽  
Copper Sulfate Pentahydrate ◽  
The Stability ◽  
High Yields ◽  
Zeta Potential Analysis

In this work, we report the synthesis of copper nanoparticles (Cu NPs), employing the chemical reduction method in an aqueous medium. We used copper sulfate pentahydrate (CuSO4·5H2O) as a metallic precursor; polyethylenimine (PEI), allylamine (AAM), and 4-aminobutyric acid (AABT) as stabilizing agents; and hydrated hydrazine as a reducing agent. The characterization of the obtained nanoparticles consisted of X-ray, TEM, FTIR, and TGA analyses. Through these techniques, it was possible to detect the presence of the used stabilizing agents on the surface of the NPs. Finally, a zeta potential analysis was performed to differentiate the stability of the nanoparticles with a different type of stabilizing agent, from which it was determined that the most stable nanoparticles were the Cu NPs synthesized in the presence of the PEI/AAM mixture. The antimicrobial activity of Cu/PEI/AABT toward P. aeruginosa and S. aureus bacteria was high, inhibiting both bacteria with low contact times and copper concentrations of 50–200 ppm. The synthesis method allowed us to obtain Cu NPs free of oxides, stable to oxidation, and with high yields. The newly functionalized Cu NPs are potential candidates for antimicrobial applications.

scholarly journals Structure and Stability of Gas Adsorption Complexes in Periodic Porous Solids as Studied by VTIR Spectroscopy: An Overview

2020 ◽  
Vol 10 (23) ◽  
pp. 8589
Author(s):  
Montserrat R. Delgado
Keyword(s):  
Gas Adsorption ◽  
Variable Temperature ◽  
Spectroscopic Technique ◽  
Porous Solids ◽  
Large Temperature ◽  
Adsorption Complexes ◽  
The Stability ◽  
Standard Enthalpy Change

Variable-temperature infrared (VTIR) spectroscopy is an instrumental technique that enables structural characterization of gas-solid adsorption complexes by analysis of meaningful vibrational modes, and simultaneous determination of the standard enthalpy change (ΔH0) involved in the gas adsorption process, which allows one to quantify the stability of the corresponding complex. This is achieved by a van’t Hoff analysis of a set of IR spectra recorded over a sufficiently large temperature range. Herein, the use of this versatile spectroscopic technique is demonstrated by reviewing its application to the study of carbon monoxide, carbon dioxide and dinitrogen adsorption on several (alkaline) zeolites, which can be regarded as the archetype of periodic porous solids.

Characterization and Oil Recovery Observations on a Series of Synthetic Petroleum Sulfonates

1982 ◽  
Vol 22 (02) ◽  
pp. 226-236 ◽  
Author(s):  
Earl W. Malmberg ◽  
Carolyn C. Gajderowicz ◽  
F. David Martin ◽  
Jill S. Ward ◽  
J.J. Taber
Keyword(s):  
New Mexico ◽  
Oil Recovery ◽  
Optimal Salinity ◽  
Aqueous Dispersions ◽  
R And D ◽  
Recovery System ◽  
Characterization Studies ◽  
The Stability

Abstract Synthetic sulfonates for application in enhanced oilrecovery are of increasing interest. Because of the needto explore the range of candidates potentially available atvarious costs from the petrochemical industry, a series ofnine samples was prepared for distribution with financial suppose of the U.S. DOE. This paper briefly describesthe samples and, in more detail, the characterization ofthe samples for oil recovery. The characterization included determination of optimal salinity, stability ofaqueous dispersions in brines containing sodium chlorideand calcium ion, and oil recovery and loss of sulfonate in1-ft (0.305-m) Berea cores. Introduction Most current work in surfactant systems for enhanced oilrecovery is based on sulfonates, either petroleum(natural) or synthetic. The synthetic sulfonates discussedin this paper are those made by alkylation of an aromatic hydrocarbon with a selected olefin, followed by sulfonationof this alkylate. Interest in these synthetic sulfonatesis evident from numerous patents and publications fromseveral laboratories. The major published work in this area, by Reed andHealy, stems from earlier studies that generated seriousquestions as to the effect of fractionation of petroleumsulfonates when used in reservoirs. Interest in andwork with synthetic sulfonates has increased steadily inthe Sun Co. laboratories over the past years because offavorable experimental results. However, availablesamples of synthetic sulfonates have been limited; theydid not include agents that probably would be thelowest cost materials available from current petrochemicaloperations. With the question of cost effectiveness inmind and with the expressed interest of a number of oilrecovery laboratories, Sun approached the Energy R and DAdmin. with the following proposal:Sun wouldprepare large samples of a representative set of syntheticsulfonates,the New Mexico Petroleum RecoveryResearch Center would distribute the samples tointerested laboratories and would receive and distributeinformation from these groups, andthis informationwould include characterization studies on the sampleswith preliminary studies by the New Mexico and Sun laboratories. This work has now been completed. The Sun Applied R and D group in Marcus Hook, PA, did the preparative work. The samples are describedbriefly in a following section; complete description isavailable in Ref. 5. This paper describes characterization of the synthetic sulfonates by optimal salinityexperiments, studies of aqueous dispersions in selectedsodium chloride and calcium chloride concentrations, and oil-recovery experiments in 1-ft (0.305-m) Bereacores. Plans for this work required a decision on the levelof concentration of sulfonate to use. One philosophyexemplified in published work is that the level should below so that, for an acceptable total amount of sulfonate, the %PV of the slug could be as large as possible. Thisapproach is an advantage in efforts to improve theoverall conformance of the recovery system in areservoir. Some interesting results have been obtained with synthetic sulfonates at the level of 2% active concentration.In studies of the stability of aqueous dispersions asin the salinity grids, 1.5% sulfonate was used. Thisvalue is expressed in terms of the aqueous phase; nosignificant oil phase was present. SPEJ P. 226^

scholarly journals Antimicrobial Activities of Hydrophobically Modified Poly(Acrylate) Films and Their Complexes with Different Chain Length Cationic Surfactants

Coatings ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 244
Author(s):  
Ioana Cătălina Gîfu ◽  
Monica Elisabeta Maxim ◽  
Ludmila Otilia Cinteza ◽  
Marcela Popa ◽  
Ludmila Aricov ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Cationic Surfactants ◽  
Antimicrobial Properties ◽  
Multilayer Films ◽  
Antimicrobial Activities ◽  
Layer By Layer ◽  
Antimicrobial Efficiency ◽  
Hydrophobically Modified ◽  
Multilayered Systems ◽  
The Stability

Multilayer films from hydrophobically modified poly(acrylic acid) (HMPA) and their complexes with cationic surfactants were successfully prepared using the layer-by-layer (LbL) method. Alkyl trimethylammonium bromide derivatives with various lengths of the hydrophobic chain (C10–C18) were used to interact with the HMPA polymer, generating highly hydrophobic domains in the films and contributing to the antimicrobial properties of the prepared coating. The antimicrobial efficiency against common pathogens such as Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Candida albicans was investigated in relationship with the morphology and composition of the thin films. The wettability and roughness of the multilayered systems were evaluated using atomic force microscopy (AFM) and contact angle measurements. The effects of the microbial exposure on the surface properties of the prepared films were investigated in order to assess the stability of the HMPA-deposited multilayers and the durability of the antimicrobial activity. The hydrophobically modified films exhibited antimicrobial activity against the studied pathogens. The best efficiency was registered in the case of S. aureus, which showed an inhibition of growth up to 100% after 2 h. C. albicans proved to be less sensitive to the effect of the multilayers deposited from HMPA–surfactant complexes. These results suggest that HMPA and HMPA–surfactant complex LbL multilayer films can be used as promising materials in antimicrobial surface coatings with increased resistance to pathogens during exposure.

On the Hydrolysis of Tetravalent Metal Ions

2000 ◽  
Vol 663 ◽  
Author(s):  
C. Ekberg ◽  
P. Brown ◽  
J. Comarmond ◽  
Y. Albinsson
Keyword(s):  
Metal Ions ◽  
Stability Constants ◽  
Safety Assessment ◽  
Experimental Conditions ◽  
Polymeric Species ◽  
The Stability ◽  
Hydrolysis Of

ABSTRACTThe stability constants of the hydroxide complexes of zirconium(IV) and uranium(IV) have been measured at 15, 25 and 35°C [in 1.0 mol dm−3 (Na, H)ClO4] using potentiometry. For zirconium(IV), the results indicate the presence of Zr(OH)3+ and the polymeric species Zr3(OH)48+ and Zr4(OH)88+ whereas the results for uranium(IV) indicate the presence of U(OH)3+ and the polymeric species U4(OH)124+. The hydrolysis of both metal ions was studied at three temperatures allowing the determination of ΔH° and ΔS° of reaction for each species. The results were compared with previous results determined for thorium(IV) under the same experimental conditions to ascertain whether thorium should be used as an analogue for other tetravalent metal ions in safety assessment studies of nuclear repositories.

Utilization of novel and rapid techniques for characterization of neem Azadirachta indica seed oil and palm oil blends

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Mehrajfatema Mulla ◽  
Jasim Ahmed ◽  
Surendraraj Alagarsamy ◽  
Sabeena Farvin K Habeebullah
Keyword(s):  
Palm Oil ◽  
Azadirachta Indica ◽  
Antimicrobial Properties ◽  
Oil Industry ◽  
Neem Oil ◽  
Oil Blends ◽  
Fatty Acids Profile ◽  
Dielectric Data

AbstractThe authentication of neem oil and its blending with inexpensive vegetable oil, such as, palm oil is a common practice in the neem oil industry. This study was conducted to investigate the neem kernel (Azadirachta indica) oil (NKO) by blending with palm oil and characterize it by studying its effect on the physicochemical properties, dielectric properties and fatty acid profiles of the blend. Blending significantly influenced the color, dielectric, structural and antimicrobial properties of the virgin oil. The NKO was rich in oleic (44.97%), stearic (21.27%), palmitic (16.88%) and linoleic acids (14.08%). The addition of palm oil into NKO significantly influenced the fatty acids profile , which was further confirmed by the FTIR spectra and the dielectric data. Overall, determination of moisture content, palmitic and stearic acid content, color parameter "a" and dielectric measurements were found to be fastest and precise way to detect the NKO and PO blends.

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