scholarly journals Investigation of partially myristoylated carboxymethyl chitosan, an amphoteric‐amphiphilic chitosan derivative, as a new material for cosmetic and dermal application

2020 ◽  
Author(s):  
Haruyoshi Seino ◽  
Naoko Kawaguchi ◽  
Yukari Arai ◽  
Noriyasu Ozawa ◽  
Kazuhiko Hamada ◽  
...  
Keyword(s):  
Carboxymethyl Chitosan ◽  
Chitosan Derivative ◽  
New Material ◽  
Dermal Application

scholarly journals Inhibition of Amphiphilic N-Alkyl-O-carboxymethyl Chitosan Derivatives on Alternaria macrospora

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Qili Liu ◽  
Jianxin Zhang ◽  
Dong Li ◽  
Jianfeng Lang ◽  
Shasha Zai ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Schiff Base ◽  
Chloroacetic Acid ◽  
Carboxymethyl Chitosan ◽  
Molecular Structures ◽  
Fatty Aldehyde ◽  
Cotton Leaf ◽  
Chitosan Derivative ◽  
Molecular Sizes ◽  
Derivatives Of

Cotton leaf spot (Alternaria macrospora) is a widespread disease that occurs in the main cotton-producing area of China. In managing this disease, a novel chitosan-based biopesticide, an amphiphilic N-alkyl-O-carboxymethyl chitosan derivative, was prepared. The product was selected from variations of chitosan with different molecular structures, which were obtained via a two-step reaction. First, carboxymethyl chitosans with varying molecular sizes were obtained by etherification with chloroacetic acid; then the carboxymethyl chitosan was alkylated with C4–C12 fatty aldehyde through a Schiff-base reaction. This procedure resulted in derivatives of amphiphilic N-alkyl-O-carboxymethyl chitosan, which showed strong antifungal activities against A. macrospora, and the efficacy was determined by its molecular structure.

Methylated 4-N,N dimethyl aminobenzyl N,O carboxymethyl chitosan as a new chitosan derivative: Synthesis, characterization, cytotoxicity and antibacterial activity

2016 ◽  
Vol 149 ◽  
pp. 131-139 ◽  
Author(s):  
Soheila Rahmani ◽  
Zohreh Mohammadi ◽  
Mohsen Amini ◽  
Elham Isaei ◽  
Sadegh Taheritarigh ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Carboxymethyl Chitosan ◽  
Chitosan Derivative

Preparation of N, O-carboxymethyl chitosan-Human-Like Collagen Microspheres for Drug Delivery

2012 ◽  
Vol 560-561 ◽  
pp. 410-414
Author(s):  
Pei Ma ◽  
Ran Su ◽  
Dai Di Fan
Keyword(s):  
Drug Delivery ◽  
Bovine Serum Albumin ◽  
Bovine Serum ◽  
Carboxymethyl Chitosan ◽  
Water Soluble ◽  
Protein Drug ◽  
Chitosan Derivative ◽  
Generation Technique ◽  
Model Protein ◽  
Hydrogel System

In this investigation, the N, O-carboxymethyl chitosan (NOCC) was synthesized. A novel pH-sensitive hydrogel system composed of a water-soluble chitosan derivative (N,O-carboxymethyl chitosan, NOCC)and Human-like collagen (HLC) blended with phosphate was developed for controlling drug delivery and NOCC–HLC microspheres were prepared by the technology of electrostatic droplet generation technique. The release profiles of a model protein drug (bovine serum albumin, BSA) from test hydrogels were studied in simulated gastric and intestinal media.

Characterization of a monolayer graphitic structure

1994 ◽  
Vol 52 ◽  
pp. 760-761
Author(s):  
X. Lin ◽  
X. K. Wang ◽  
V. P. Dravid ◽  
J. B. Ketterson ◽  
R. P. H. Chang
Keyword(s):  
Three Dimensional ◽  
Single Layer ◽  
Synthesis Process ◽  
Graphitic Structure ◽  
Positive Gaussian Curvature ◽  
Graphitic Sheet ◽  
Structural And Electronic Properties ◽  
New Material ◽  
Hexagonal Network

For small curvatures of a graphitic sheet, carbon atoms can maintain their preferred sp2 bonding while allowing the sheet to have various three-dimensional geometries, which may have exotic structural and electronic properties. In addition the fivefold rings will lead to a positive Gaussian curvature in the hexagonal network, and the sevenfold rings cause a negative one. By combining these sevenfold and fivefold rings with sixfold rings, it is possible to construct complicated carbon sp2 networks. Because it is much easier to introduce pentagons and heptagons into the single-layer hexagonal network than into the multilayer network, the complicated morphologies would be more common in the single-layer graphite structures. In this contribution, we report the observation and characterization of a new material of monolayer graphitic structure by electron diffraction, HREM, EELS.The synthesis process used in this study is reported early. We utilized a composite anode of graphite and copper for arc evaporation in helium.

Cross-sectional TEM specimen preparation from magneto-optical disk by ultramicrotomy

1993 ◽  
Vol 51 ◽  
pp. 236-237
Author(s):  
F. Shaapur ◽  
M.J. Kim ◽  
Seh Kwang Lee ◽  
Soon Gwang Kim
Keyword(s):  
System Development ◽  
Thin Foil ◽  
Specimen Preparation ◽  
Material System ◽  
Cross Sectional ◽  
Protective Layers ◽  
New Material ◽  
Diamond Saw ◽  
Original Production ◽  
Thick Medium

TEM characterization and microanalysis of the recording media is crucial and complementary to new material system development as well as quality control applications. Due to the type of material generally used for supporting the medium, i.e., a polymer, conventional macro- and microthinning procedures for thin foil preparation are not applicable. Ultramicrotorny (UM) is a viable option and has been employed in previous similar studies. In this work UM has been used for preparation of XTEM samples from a magneto-optical (MO) recording medium in its original production format.The as-received material system consisted of a 4-layer, 2100 Å thick medium including a 300 Å TbFeCo layer enveloped by silicon nitride protective layers supported on a 1.2 mm thick × 135 mm (5.25 in.) diameter polycarbonate disk. Recording tracks had an approximate pitch of 1.6 μm separated by 800 Å deep peripheral grooves. Using a Buehler Isomet low-speed diamond saw, 1 mm wide and 20 mm long strips were cut out of the disk along the recording tracks.

The Case of Thematic Tests Adapted to Older Adults

2011 ◽  
Vol 32 (1) ◽  
pp. 46-71 ◽  
Author(s):  
Benoît Verdon
Keyword(s):  
Older Adults ◽  
Older Persons ◽  
Older Men ◽  
Elderly Persons ◽  
Mental Processes ◽  
Men And Women ◽  
Projective Tests ◽  
New Material ◽  
Older Men And Women ◽  
Latent Content

Since the 1950s, the growing interest of clinicians in using projective tests to study normal or pathological aging processes has led to the creation of several thematic tests for older adults. This development reflects their authors’ belief that the TAT is not suitable to the concerns and anxieties of elderly persons. The new material thus refers explicitly to situations related to age; it aims to enable older persons to express needs they cannot verbalize during consultations. The psychodynamic approach to thematic testing is based on the differentiation between the pictures’ manifest and latent content, eliciting responses linked to mental processes and issues the respondent is unaware of. The cards do not necessarily have to show aging characters to elicit identification: The situations shown in the pictures are linked to loss, rivalry, helplessness, and renunciation, all issues elderly respondents can identify with and that lead them to express their mental fragilities and resources. The article first explains the principles underlying four of these thematic tests, then develops several examples of stories told for card 3BM of the TAT, thus showing the effectiveness of this tool for the understanding and differentiation of loss-related issues facing older men and women.

Increase of resistance of piercing mill mandrels at seamless pipes production of 13Cr grade martensite class stainless steel at line ТПА 159‒426 of JSC VTZ

2020 ◽  
Vol 76 (12) ◽  
pp. 1259-1264
Author(s):  
I. I. Lube ◽  
N. V. Trutnev ◽  
S. V. Tumashev ◽  
A. V. Krasikov ◽  
A. G. Ul’yanov ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Oil And Gas ◽  
Cobalt Content ◽  
Pipe Plant ◽  
Piercing Mill ◽  
Steel Strength ◽  
New Material ◽  
Chemical Composition Of Steel ◽  
Technical Solutions ◽  
Grade Steel

At production of pipes of type 13Cr grade steel used at development of oil and gas deposits in areas with aggressive environment, intensive wear of instrument takes place, first of all, piercing mill mandrels. Factors, influencing the resistivity of the piercing mandrels considered, including chemical composition of the material, the mandrel is made of and its design. Based on industrial experience it was shown, that chrome content in the mandrel material practically does not affect on the increase of its resistivity, since the formed thin protective oxides having high melting temperature, are quickly failed and practically are not restored in the process of piercing. To increase the resistivity of piercing mandrels at production of casing tubes of type 13Cr grade steel, a work was accomplished to select a new material for their manufacturing. The chemical composition of steel presented, which was traditionally used for piercing mandrels manufacturing, as well as a steel grade proposed to increase their resistivity. First, molybdenum content was increased, which increases the characteristics of steel strength and ductility at high temperatures and results in grain refining. Second, tungsten content was also increased, which forms carbides in the steel resulting in an increase of its hardness and “red resistivity”, as well as in preventing grains growth during heating. Third, cobalt content was also increased, which increases heat resistivity and shock loads resistivity. The three elements increase enabled to increase the mandrels resistivity by two times. Results of mandrel test of steel 20ХН2МВ3КБ presented, the mandrel having corrugation on the working cone surface, which enabled to reach the resistivity growth to 12 passes without significant change of instrument cost. Microstructure of mandrels made of steels 20Х2Н4МФА and 20ХН2МВ3КБ shown. Application of the centering pin of special design was tested, which provided forming of a rounding edge on the front billet ends, eliminated undercut of mandrel external surface in the process of secondary billet grip and increase the service life of the piercing mill mandrels. At production of seamless pipes of martensite class type 13Cr stainless steels having L80 group of strength, an increase of piercing mandrel resistivity was reached by more than four times, which together with other technical solutions enabled to increase the hourly productivity of the hot rolling section of Volzhsky pipe plant ТПА 159-426 line by more than two times.

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