Effect of chitosan second layer on the gelation and controlled digestion of Citrem-chitosan bilayer emulsions

2022 ◽  
Author(s):  
Kunal Kadiya ◽  
Manisha Sharma ◽  
Supratim Ghosh
Keyword(s):  
Chitosan Concentration ◽  
Secondary Layer

This research aimed to induce repulsive gelation in Citrem-stabilized O/W emulsions by creating a secondary layer of chitosan around the droplets. A range of chitosan concentration (0-0.25wt%) and degree of...

Enhancing Dye-ability and Antibacterial Features of Silk through Pre-treatment with Chitosan

2013 ◽  
Vol 8 (3) ◽  
pp. 155892501300800 ◽  
Author(s):  
Mehrsa Hosseini ◽  
Majid Montazer ◽  
Rogheih Damerchely
Keyword(s):  
Antibacterial Properties ◽  
Reactive Dyes ◽  
Color Difference ◽  
Reactive Dye ◽  
Light Fastness ◽  
Chitosan Concentration ◽  
Washing Durability ◽  
Color Yield ◽  
Pre Treatment ◽  
Antibacterial Potential

Biopolymers are suitable replacement materials for different chemical processes. In this work, silk yarns were treated with different chitosan concentration and then dyed with mono and bi-functional reactive dyes. The color yield, color difference and color fastness to light and washing of the dyed silk yarns were evaluated. Also, the effects of chitosan concentration, type of the reactive dyes on dye uptake of samples were studied. The bi-functional reactive dye has a high adsorption compared to mono-functional ones. The silk yarn treated with 3% chitosan had higher K/S values, washing and light fastness. The effects of chitosan on the antibacterial properties of silk yarns against two kinds of bacteria: Staphylococcus aureus and Escherichia coli were investigated. The treated silk samples were found to have antibacterial potential due to the antibacterial property of chitosan. Scanning electron microscopy (SEM) photographs reveal the deposition of chitosan on the treated yarns. Washing durability, handle properties, and yellowness of treated and dyed samples were also investigated.

scholarly journals Oxygen isotope equilibrium in brachiopod shell fibres in the context of biological control

2008 ◽  
Vol 72 (1) ◽  
pp. 239-242 ◽  
Author(s):  
M. Cusack ◽  
A. Pérez-Huerta ◽  
P. Chung ◽  
D. Parkinson ◽  
Y. Dauphin ◽  
...  
Keyword(s):  
Oxygen Isotope ◽  
Isotope Composition ◽  
Seawater Temperature ◽  
Environmental Data ◽  
Ambient Seawater ◽  
Secondary Layer ◽  
Vital Effect ◽  
Vital Effects ◽  
Stable Oxygen ◽  
Isotope Equilibrium

With their long geological history and stable low-Mg calcite shells, Rhynchonelliform brachiopods are attractive sources of environmental data such as past seawater temperature (Buening and Spero, 1996; Auclair et al., 2003; Brand et al., 2003; Parkinson et al., 2005). Concerns about the influence of vital effects on the stable isotope composition of brachiopod shells (Popp et al., 1986), led to isotope analyses of different parts of brachiopod shells in order to identify those parts of the shell that are influenced by any vital effect and those parts that may be suitable recorders of seawater temperature via stable oxygen isotope composition (Carpenter and Lohmann, 1995; Parkinson et al., 2005). Such detailed studies demonstrated that the outer primary layer of acicularcalcite is isotopically light in both δ18O and δ13C while the secondary layer, composed of calcite fibres, is in oxygen-isotope equilibrium with ambient seawater(Fig. 1) (Parkinson et al., 2005).

scholarly journals Synthesis and Optimization of Chitosan Ceramic-Supported Membranes in Pervaporation Ethanol Dehydration

Membranes ◽  
2018 ◽  
Vol 8 (4) ◽  
pp. 119 ◽  
Author(s):  
Mahdi Nikbakht Fini ◽  
Sepideh Soroush ◽  
Mohammad Montazer-Rahmati
Keyword(s):  
Separation Factor ◽  
Low Cost ◽  
Chitosan Solution ◽  
Feed Water ◽  
Permeation Flux ◽  
Hybrid Membranes ◽  
Alumina Support ◽  
Membrane Performance ◽  
Chitosan Concentration ◽  
Angle Measurements

In the present work, ceramic-supported chitosan hybrid membranes were prepared for the pervaporation dehydration of ethanol. Mullite and combined mullite-alumina (50% alumina content) tubular low-cost ceramic supports were fabricated, and their influence on membrane performance was compared to a commercial α-alumina support. The membrane preparation parameters were different ceramic supports and the concentration of chitosan solution (varying from 2 wt.% to 4 wt.%). The supports and hybrid membranes were characterized by field emission scanning electron microscopy (FE-SEM) and contact angle measurements. The results show, with increasing chitosan concentration, the permeability decreases, and selectivity increases. It was also found that the separation factor decreases with increasing feed temperature and feed water content, while the permeation flux increases. The membrane that was coated on α-alumina support with a 3 wt.% chitosan concentration exhibited the best pervaporation performance, leading to a permeation flux and separation factor of 352 g·m−2·h−1 and 200 for 90 wt.% ethanol in feed at 60 °C, respectively.

scholarly journals Variation in brachiopod microstructure and isotope geochemistry under low pH–ocean acidification–conditions

2018 ◽  
Author(s):  
Facheng Ye ◽  
Hana Jurikova ◽  
Lucia Angiolini ◽  
Uwe Brand ◽  
Gaia Crippa ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Ocean Acidification ◽  
Isotope Geochemistry ◽  
Shell Growth ◽  
Low Ph ◽  
Secondary Layer ◽  
Ph Conditions ◽  
One Year ◽  
The Impact ◽  
Δ13c And Δ18o

Abstract. Throughout the last few decades and in the near future CO2–induced ocean acidification is potentially a big threat to marine calcite-shelled animals (e.g., brachiopods, bivalves, corals and gastropods). Despite the great number of studies focusing on the effects of acidification on shell growth, metabolism, shell dissolution and shell repair, the consequences on biomineral formation remain poorly understood, and only few studies addressed contemporarily the impact of acidification on shell microstructure and geochemistry. In this study, a detailed microstructure and stable isotope geochemistry investigation was performed on nine adult brachiopod specimens of Magellania venosa (Dixon, 1789), grown in the natural environment as well as in controlled culturing experiments at different pH conditions (ranging 7.35 to 8.15 ± 0.05) over different time intervals (214 to 335 days). Details of shell microstructural features, such as thickness of the primary layer, density and size of endopunctae and morphology of the basic structural unit of the secondary layer were analysed using scanning electron microscopy (SEM). Stable isotope compositions (δ13C and δ18O) were tested from the secondary shell layer along shell ontogenetic increments in both dorsal and ventral valves. Based on our comprehensive dataset, we observed that, under low pH conditions, M. venosa produced a more organic-rich shell with higher density of and larger endopunctae, and smaller secondary layer fibres, when subjected to about one year of culturing. Also, increasingly negative δ13C and δ18O values are recorded by the shell produced during culturing and are related to the CO2–source in the culture setup. Both the microstructural changes and the stable isotope results are similar to observations on brachiopods from the fossil record and strongly support the value of brachiopods as robust archives of proxies for studying ocean acidification events in the geologic past.

scholarly journals Uji Aktivitas Antioksidan N-Metil Kitosan Berkelarutan Tinggi

2018 ◽  
Vol 14 (1) ◽  
pp. 107
Author(s):  
Mardiyah Kurniasih ◽  
Purwati Purwati ◽  
Ratna Stia Dewi ◽  
Susi Fatimah
Keyword(s):  
Antioxidant Activity ◽  
Acetic Acid ◽  
High Solubility ◽  
Chitosan Concentration ◽  
Ferric Thiocyanate ◽  
Activity Test ◽  
Dpph Method

<p>Telah dilakukan uji aktivitas antioksidan dari N-metil kitosan yang memiliki kelarutan tinggi. Uji aktivitas antioksidan dilakukan dengan menggunakan metode DPPH (1,1-diphenyl-2-pikrilhidrazil) dan metode FTC (<em>ferric thiocyanate</em>). Optimasi sintesis dilakukan untuk memperoleh N-metil kitosan dengan kelarutan tinggi. Hasil penelitian menunjukkan bahwa N-metil kitosan yang berkelarutan paling tinggi adalah N-metil kitosan yang disintesis dengan 1,7 mL formaldehid 10%. Berdasarkan hasil uji aktivitas antioksidan menggunakan metode DPPH dapat diketahui bahwa N-metil kitosan merupakan antioksidan sedang dengan nilai IC<sub>50</sub> sebesar 145,398 ppm. Hasil pengujian antioksidan metode FTC menunjukkan bahwa N-metil kitosan memiliki kemampuan menghambat terbentuknya senyawa radikal bebas yang disebabkan oleh oksidasi asam lemak.</p><p><strong>An Antioxidant Activity Test of High Solubility N-Methyl Chitosan</strong><strong>.</strong> An antioxidant activity test of high solubility N-methyl chitosan has been performed. The antioxidant activity test was performed using DPPH (1,1-diphenyl-2-pikrilhidrazil) and FTC method (ferric thiocyanate). The synthesis optimization was performed to obtain high N-methyl chitosan solubility. The results showed that N-methyl chitosan with the highest solubility in 1% acetic acid solvent was N-methyl chitosan which was synthesized with 1.7 mL formaldehyde 10%. Based on the results of antioxant activity test using DPPH method can be seen that N-methyl chitosan is a medium antioxidant with IC<sub>50</sub> value of 145.398 ppm. The result of antioxidant test of FTC method showed that N-methyl chitosan has antioxidant activity with tendency to increase along with the increase of N-methyl chitosan concentration.</p>

Effect of pH and chitosan concentration on precipitation and morphology of hierarchical porous silica

2011 ◽  
Vol 357 (19-20) ◽  
pp. 3513-3519 ◽  
Author(s):  
Thongthai Witoon ◽  
Soponwit Tepsarn ◽  
Puscharapon Kittipokin ◽  
Ben Embley ◽  
Metta Chareonpanich
Keyword(s):  
Porous Silica ◽  
Effect Of Ph ◽  
Chitosan Concentration ◽  
Hierarchical Porous

scholarly journals Facile Synthesis of Silver Nanoparticles Under γ-Irradiation: Effect of Chitosan Concentration

2009 ◽  
Author(s):  
N. M. Huang ◽  
S. Radiman ◽  
H. N. Lim ◽  
P. S. Khiew ◽  
W. S. Chiu ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Irradiation Effect ◽  
Facile Synthesis ◽  
Γ Irradiation ◽  
Chitosan Concentration
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