scholarly journals Perspective in using chitosan films for sensors

2020 ◽  
Author(s):  
Raluca Maria Aileni ◽  
Laura Chiriac ◽  
Irina Sandulache
Keyword(s):  
Molecular Weight ◽  
Surface Resistance ◽  
Cotton Fabrics ◽  
Surface Conductivity ◽  
Particle Content ◽  
Sensor Development ◽  
Hydrophilic Nature ◽  
Hydrophilic Character ◽  
Chitosan Films ◽  
Almost All

This paper presents some aspects concerning the possibilities of using chitosan films for sensor development. The proposed approaches consist of the development of the experimental samples using 100% cotton fabrics (plain weave) coated with a conductive paste based on chitosan (low, medium, and high molecular weight) and copper microparticles. Our samples were obtained using the scraping method and free drying (24 h), followed by crosslinking 2-3 minutes at 150-160°C. Surface resistance was investigated using the resistance tester based on two parallel electrodes. The results showed that textile coated with chitosan paste with metallic particle content has a poorly conductive character. Based on the surface resistivity, was calculated the surface conductivity. Using the VCA Optima device was investigated the surface wettability by contact angle to conclude if the samples present a hydrophilic or hydrophobic character. After these tests, we concluded that almost all samples have a hydrophilic character due in large part to the fact that this polymer (chitosan) has hydrophilic nature.

Removal of Hydrophobic and Hydrophilic Constituents by Anion Exchange Resin

1999 ◽  
Vol 40 (9) ◽  
pp. 207-214 ◽  
Author(s):  
J.-P. Croué ◽  
D. Violleau ◽  
C. Bodaire ◽  
B. Legube
Keyword(s):  
Molecular Weight ◽  
Anion Exchange ◽  
Water Source ◽  
Atomic Ratio ◽  
Size Exclusion ◽  
Salting Out ◽  
Anion Exchange Resins ◽  
Hydrophilic Character ◽  
Exchange Resins

The objective of this work was to compare the affinity of well characterized NOM fractions isolated from two surface waters with strong (gel matrix and macroporous matrix) and weak anion exchange resins (AER) using batch experiment conditions. The structural characterization of the fraction of NOM has shown that the higher the hydrophilic character, the lower the C/O atomic ratio, the lower the SUVA, the lower the aromatic carbon content and the lower the molecular weight. In general (not always), strong AER was more efficient to remove DOC than weak AER. For the same water source (Suwannee River), the higher the molecular weight of the NOM fraction, the lower the affinity with AER. Increasing the ionic strength favored the removal of the hydrophobic NOM fraction (“salting out” effect) while increasing the pH apparently reduced the removal of the hydrophilic NOM fraction. Results were discussed in terms of size exclusion, adsorption, anion exchange and also hydrophobic/hydrophilic repulsion.

Study On Combustibility of Urethane-Modified Polyisocyanurate Foam

1983 ◽  
Vol 1 (5) ◽  
pp. 348-363 ◽  
Author(s):  
Yoshio Imai ◽  
Takao Inukai ◽  
Masato Tamashima
Keyword(s):  
Molecular Weight ◽  
Polyurethane Foams ◽  
Lower Molecular Weight ◽  
Combustion Behavior ◽  
Smoke Generation ◽  
Rigid Poly ◽  
Almost All

The relation between components of urethane-modified polyisocyanurate foams and their combustion behavior was observed to compare with rigid poly urethane foams, using the specially designed burning test apparatuses. Accord ing to the vertical smoke-weight determination for chipped samples, almost all foams lost their weight at about 650 °C. The amount of generated smoke became maximum at about 500 °C for polyurethane foams and at about 600 °C for polyisocyanurate foams. According to the horizontal smoke-concentration deter mination for small plate samples, fires occurred with much amount of generated smoke at about 600 °C. Through both the testings, adoption of higher functional isocyanate, secondary polyol, lower molecular weight polyol, or amine catalyst brought much smoke generation. Polyisocyanurate foams showed little smoke as compared with polyurethane foams.

scholarly journals A new case of deficiency of the R binder for cobalamin, with observations on minor cobalamin-binding proteins in serum and saliva

Blood ◽  
1982 ◽  
Vol 59 (1) ◽  
pp. 152-156
Author(s):  
R Carmel
Keyword(s):  
Molecular Weight ◽  
Alcohol Abuse ◽  
Incidental Findings ◽  
Clinical Presentation ◽  
Binding Capacity ◽  
Normal Serum ◽  
Serum Component ◽  
Almost All ◽  
Normal Controls ◽  
Low Serum

A patient presented at the age of 77 yr with a low serum cobalamin level. Subsequent study showed that he had persistently very low R binder (TC I) cobalamin-binding capacity in serum (less than 5 ng/liter versus 213 +/- 171 ng/liter in normal controls), and that almost all of his endogenous serum cobalamin was carried by TC II instead of TC I. His saliva also demonstrated virtually undetectable R binder (binding capacity of 31–38 ng/liter versus 41,690 +/- 23,820 ng/liter for control subjects). Unlike previous cases of R binder deficiency, he seemed to maintain normal serum cobalamin levels while receiving monthly cyanocobalamin injections. This and his normal serum unsaturated binding capacity were due to elevated TC II levels. TC II carried 72%-98% of his endogenous cobalamin, the rest being attached to minor binders. As incidental findings, the patient had a serum component of molecular weight of approximately 70,000 that carried 7%- 8% of his endogenous cobalamin and also had small quantities of TC II demonstrable in his saliva. Both these heretofore unappreciated minor peaks were identifiable because of the lack of R binder. The patient's clinical presentation supports the conclusion that R binder deficiency is a benign disorder. Whether his mild hypersegmentation of neutrophils and neuropathy were related to the R binder deficiency or, more likely, arose from coexisting folate deficiency and alcohol abuse, the overall picture contrasts dramatically with the severe clinical sequelae of TC II deficiency.

Effect of the Lactide/Glycolide Ratio and Molecular Weight of PLGA on the Bovine BMPs Microspheres Systems

2012 ◽  
Vol 466-467 ◽  
pp. 405-410 ◽  
Author(s):  
Z.H. Li ◽  
Ji Min Wu ◽  
Y.L. Zhao ◽  
J. Guan ◽  
S.J. Huang ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Encapsulation Efficiency ◽  
Double Emulsion ◽  
Copolymer Composition ◽  
Plga Microspheres ◽  
Porous Structures ◽  
Particle Properties ◽  
Internal Morphology ◽  
Almost All

The present investigation was aimed at optimization of BMPs loaded PLGA microspheres formulations resulting in improved encapsulation efficiency and sustained release of BMPs by varying the molecular weight and copolymer composition of PLGA. Double-emulsion solvent evaporation method was used to prepare the microspheres. The effect of polymer molecular weight and copolymer composition on particle properties and release behavior in vitro was reported. The particle size and encapsulation efficiency increased with increase in molecular weight and lactide content of PLGA. While BMPs release in vitro decreased with increase in molecular weight and lactide content of PLGA. SEM pictures revealed that almost all microspheres were spherical but internal morphology was different. The morphology of PLGA microspheres with exorbitant molecular weight(100kD) was anomalistic whereas the morphology of PLGA microspheres with higher glycolide content(50) have porous structures.

Size fractionation characterisation of removed organics in reverse osmosis concentrates by ferric chloride

2011 ◽  
Vol 63 (9) ◽  
pp. 1795-1800 ◽  
Author(s):  
A. Y. Bagastyo ◽  
J. Keller ◽  
D. J. Batstone
Keyword(s):  
Molecular Weight ◽  
Reverse Osmosis ◽  
Ferric Chloride ◽  
Membrane Separation ◽  
Fulvic Acids ◽  
Cell System ◽  
Humic And Fulvic Acids ◽  
Stirred Cell ◽  
Almost All ◽  
Reverse Osmosis Concentrates

Reverse osmosis membrane separation is the leading method for manufacturing potable purified water. It also produces a concentrate stream, namely reverse osmosis concentrates (ROC), with 10–20% of the water, and almost all other compounds. One method for further treating this stream is by coagulation with ferric chloride. This study evaluates removed organics in ROC treated with ferric chloride. Fractionation with ultrafiltration membranes allows separation of organics based on a nominal molecular weight. A stirred cell system was applied for serial fractionation to classify organic compounds into six groups of <0.5 kDa, 0.5–1 kDa, 1–3 kDa, 3–5 kDa, 5–10 kDa and >10 kDa. The study found that raw ROC is rich in low molecular weight compounds (<1 kDa) with almost 50% of the organics. These compounds include soluble microbial products (SMPs) and smaller humic and fulvic acids as indicated by fluorescence scanning. Conversely, colour was mostly contributed by medium to large molecules of humic and fulvic acids (>0.5 kDa). Organics and colour were reduced in all molecular groups at an optimum treatment dose 1.48 mM FeCl3 and a pH of 5. However, ferric seemed to effectively remove colour in all size ranges while residual nitrogen was found mostly in the <1 kDa sizes. Further, the fluorescence indicated that larger humic and fulvic acids were removed with considerable SMPs remaining in the <0.5 kDa.

Chemical Reactions of Rubber

1943 ◽  
Vol 16 (1) ◽  
pp. 111-123
Author(s):  
R. L. Sibley
Keyword(s):  
Molecular Weight ◽  
Atmospheric Pressure ◽  
Rapid Heating ◽  
Slow Heating ◽  
Gutta Percha ◽  
Volatile Products ◽  
Almost All ◽  
Isomeric Product ◽  
Derivatives Of ◽  
Complete Investigation

Abstract Most of the literature descriptive of the various known derivatives of rubber is found published as patents rather than as technical papers, thus indicating the commercial possibilities that may be expected from these developments. Fisher, Schidrowitz and, more recently, Jones have summarized and discussed the chemistry of rubber and its commercial derivatives. The decomposition of rubber by heat has been studied by several investigators. Williams showed that isoprene is one of the main products formed by the destructive distillation of either caoutchouc or gutta percha. Later investigators have shown that slow heating in vacuo at 300° C converts somewhat more than one-half of rubber hydrocarbon into a solid, thermoplastic, isomeric product, which has a high molecular weight and less unsaturation than that of the original hydrocarbon. Rapid heating, especially in vacuo, converts almost all the rubber into volatile products. The most complete investigation of the products obtained by the heat decomposition of rubber apparently was carried out by Midgley and Henne. These investigators destructively distilled 200 pounds of pale crepe rubber in 16-pound batches by raising the temperature as rapidly as possible to 700° C at atmospheric pressure in an iron kettle. The condensate was fractionally distilled, and cuts were made every degree between 50 to 176° C. Each cut was then separately examined. Twenty-three different hydrocarbons were identified in the distillate.

A novel high-molecular-weight flame retardant for cotton fabrics

Cellulose ◽  
2020 ◽  
Vol 27 (6) ◽  
pp. 3501-3515 ◽  
Author(s):  
Shidong Liu ◽  
Caiyan Wan ◽  
Yu Chen ◽  
Rui Chen ◽  
Fengxiu Zhang ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Flame Retardant ◽  
High Molecular Weight ◽  
Cotton Fabrics

scholarly journals Extraction and Characterization of Collagen from Sand Sea Cucumber (Holothuria scabra)

2021 ◽  
Vol 26 (3) ◽  
pp. 319-327
Author(s):  
Gita Syahputra ◽  
Hariyatun Hariyatun ◽  
Muhammad Firdaus ◽  
Pugoh Santoso
Keyword(s):  
Molecular Weight ◽  
Sea Cucumber ◽  
Type I ◽  
Indonesian Seas ◽  
Holothuria Scabra ◽  
Aquatic Product ◽  
Electron Microscopy Analysis ◽  
Main Component ◽  
Almost All

Sand sea cucumber (Holothuria scabra) is an aquatic product that belongs to Echinodermata, a habitant in almost all Indonesian seas. The main component of the sea cucumber is protein, one of which is collagen. This study aimed to extract and characterize collagen from the species using the acid-base extraction method. The characterization of sea cucumber collagen includes molecular weight, amino acid components, Fourier transform infrared spectrophotometry, and scanning electron microscopy analysis. This study has successfully extracted collagen from the sample using an extraction system: NaOH 0.1 M; CH3COOH 0.1 M; and distilled water under 45°C treatments, gave 6% yield. The collagen has a molecular weight 110-130 kDa. Based on the infrared spectra, the specific functional groups of the collagen are amide A (3379.29 cm-1), amide B (2924.09 cm-1), amide I (1681.93 cm-1), amide II (1560.41 cm-1), and amide III (1249.87 cm-1). The collagen falls into type I. We suggest an alternative resource of collagen from sand sea cucumber, other than poultry and mammals.   Keywords: characterization, collagen, extraction, fishery, sand sea cucumber

SOME CHARACTERISTICS OF THE ORGANIC MATTER EXTRACTED BY DILUTE INORGANIC ACIDS FROM A PODZOLIC B HORIZON

1958 ◽  
Vol 38 (1) ◽  
pp. 14-22 ◽  
Author(s):  
J. R. Wright ◽  
M. Schnitzer ◽  
R. Levick
Keyword(s):  
Molecular Weight ◽  
Organic Matter ◽  
Average Molecular Weight ◽  
Paper Electrophoresis ◽  
Distilled Water ◽  
Number Average Molecular Weight ◽  
Inorganic Acids ◽  
Halogen Content ◽  
Ph Range ◽  
Almost All

Organic matter was extracted from the B21horizon of a podzol soil by both 0.5 per cent HF and 0.5 per cent HCl. Dialysis of the extracts against distilled water reduced the halogen content to less than 0.1 per cent and the iron plus aluminium to between two and three millimoles per gram of organic matter. Further treatment of this water-dialysed material with EDTA and 8-hydroxyquinoline removed almost all of the iron and about two-thirds of the aluminium.The number average molecular weight of the organic matter, as determined by osmometry, ranged between 47,000 and 53,800. Paper electrophoresis studies showed that this organic matter consisted chiefly of one component, negatively charged, dark-brown in colour and mobile over the pH range investigated (1.8 – 9.0). Only traces to small amounts of glucose, galactose, arabinose and xylose were detected by paper chromatography in both the HF and HCl extracts even after hydrolysis. In addition traces of rhamnose were found in the hydrolyzed HF extract.

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