Preparation and characterization of individual chitin nanofibers with high stability from chitin gels by low-intensity ultrasonication for antibacterial finishing

Cellulose ◽  
2017 ◽  
Vol 25 (2) ◽  
pp. 999-1010 ◽  
Author(s):  
Haizhong Zou ◽  
Baofeng Lin ◽  
Chuanhui Xu ◽  
Minjie Lin ◽  
Wei Zhan
1994 ◽  
Vol 47 (1) ◽  
pp. 131 ◽  
Author(s):  
JB Peel ◽  
RG Rothwell

The isolation and spectroscopic characterization of halogenated fullerene-60 compounds has not advanced greatly during the 2 years of effort in this area. While the fully fluorinated C60F60 has been studied in some detail, other halogen addition processes have indicated chlorination up to C60Cl24 and bromination up to C60Br24. However, definitive structural information has to date only been provided for three compounds, namely C60Br6, C60Br6 and C60Br24. Iodine does not appear to form genuine addition compounds. In the work reported here semiempirical calculations using the AM1 approximation with the MOPAC molecular orbital program have been directed to comparing the possible stable isomers of the 1:1 addition compounds C60X2 for X = F, Cl and Br. The favoured isomers can be described as 1,2-additions (to a double bond at a hexagon-hexagon fusion) and 1,4-additions (to the terminal carbons of a butadiene moiety) with higher-energy isomers resulting from 1,6- and 1,8-additions. The other isomers represented by 1,3- 1,5- and 1,7-additions are only stable relative to dissociation in the case of the fluorine addition compounds. By contrast for Br2 addition only the 1,2- and 1,4-isomers are stable toward dissociation. The calculations show that, at and near the addition site carbons, X2 addition is adequately described in terms of local distortion of the C60 sphere. The elementary model of C60 as comprising formal single and double bonds is relevant since C60 behaves as a 'poly- alkene ', with sp3 carbons replacing sp2 carbons at the addition sites. This model offers an explanation for the unique structures observed for C60Br6 and C60Br24 which the AM1calculations show to be very stable toward dissociation. However, the experimental C60Br8 structure is found to be relatively less stable than another isomer. Also high-stability isomers of C60Br4, C60Br10, C60Br12 and C60Br18 are predicted.


2010 ◽  
Vol 24 (25) ◽  
pp. 2591-2599 ◽  
Author(s):  
M. H. YOUSEFI ◽  
A. A. ABDOLHOSSEINZADEH ◽  
H. R. FALLAH ◽  
A. A. KHOSRAVI

A fast-chemically capping method in aqueous solution was developed to synthesize CdS and CdS : Ag luminescent nanoparticles and particles with sizes between 2–4 nm. The achieving of well-dispersed and narrow-sized particles in colloidal solution and also, high stability of them using mercaptoethanol (ME) as a capping agent was established. Quantum confinement effect was observed in UV-vis absorption as well as in PL spectra. PL spectroscopy also showed green emission and Ag dopants caused a faster energy transfer between CdS inter-bands. XRD patterns exhibited that both cubic and hexagonal phases exist in solutions. Ultimately, TEM images captured from QDs displayed the shapes of nanoclusters which are almost spherical.


2020 ◽  
Vol 15 (6) ◽  
pp. 15-27
Author(s):  
NUR AMALINA RAMLI ◽  
◽  
NORA’AINI ALI ◽  
SOFIAH HAMZAH

This research was intended to synthesize liposome as a nanocarrier to encapsulate quercetin, which is prone to degradation and susceptible to low bioavailability upon oral administration. The liposomes were synthesized by thin-film hydration method and followed by probe sonication for downsizing. Soy phosphatidylcholine (SPC) and cholesterol (CHOL) were employed as the composition of the phospholipid bilayer. Results indicated a dependence of sonication amplitude and time in the formation of free liposomes (FL). The average size of quercetin-loaded liposomes (QL) prepared was 346.4 nm with a narrow polydispersity index (0.22) and a high magnitude of zeta potential (-49.6 mV). These characterizations depict that a homogenous nanovesicle suspension with high stability was successfully synthesized. Quercetin was incorporated into the liposomes with a high encapsulation efficiency of 90.7% and loading capacity of 9.3%. This viable nanocarrier perhaps will provide ingenious protection for a wider spectrum of active agents in food and biopharmaceutical products.


2014 ◽  
Vol 21 (6) ◽  
pp. 1367-1369 ◽  
Author(s):  
Weihe Xu ◽  
Kenneth Lauer ◽  
Yong Chu ◽  
Evgeny Nazaretski

A rotational stage is a key component of every X-ray instrument capable of providing tomographic or diffraction measurements. To perform accurate three-dimensional reconstructions, runout errors due to imperfect rotation (e.g.circle of confusion) must be quantified and corrected. A dedicated instrument capable of full characterization and circle of confusion mapping in rotary stages down to the sub-10 nm level has been developed. A high-stability design, with an array of five capacitive sensors, allows simultaneous measurements of wobble, radial and axial displacements. The developed instrument has been used for characterization of two mechanical stages which are part of an X-ray microscope.


2019 ◽  
Vol 55 (1) ◽  
pp. 83-86 ◽  
Author(s):  
Aswathy Joseph ◽  
Marylin Mary Xavier ◽  
Jacek Fal ◽  
Gaweł Żyła ◽  
Soorya Sasi ◽  
...  

An iron oxide based-electroactive IoNanofluid with a high dielectric constant, high stability and low viscosity was synthesized from ferrous sulphate heptahydrate via a facile microwave assisted one-step route in 1-butyl-4-methylpyridinium chloride.


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