scholarly journals Crosslinking of Gelatin in Bicomponent Electrospun Fibers

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3391
Author(s):  
Judyta Dulnik ◽  
Paweł Sajkiewicz
Keyword(s):  
Reaction Times ◽  
Solution Concentration ◽  
Solvent System ◽  
Diglycidyl Ether ◽  
Electrospun Fibers ◽  
Aqueous Environment ◽  
Chemical Crosslinking ◽  
Crosslinking Degree ◽  
System A ◽  
Series Of Experiments

Four chemical crosslinking methods were used in order to prevent gelatin leaching in an aqueous environment, from bicomponent polycaprolactone/gelatin (PCL/Gt) nanofibers electrospun from an alternative solvent system. A range of different concentrations and reaction times were employed to compare genipin, 1-(3-dimethylaminopropyl)-N’-ethylcarbodimide hydrochloride/N-hydroxysuccinimide (EDC/NHS), 1,4-butanediol diglycidyl ether (BDDGE), and transglutaminase. The objective was to optimize and find the most effective method in terms of reaction time and solution concentration, that at the same time provides satisfactory gelatin crosslinking degree and ensures good morphology of the fibers, even after 24 h in aqueous medium in 37 °C. The series of experiments demonstrated that, out of the four compared crosslinking methods, EDC/NHS was able to yield satisfactory results with the lowest concentrations and the shortest reaction times.

Direct conversion of cellulose to ethyl levulinate catalysed by modified fibrous mesoporous silica nanospheres in a co-solvent system

2021 ◽  
Vol 45 (12) ◽  
pp. 5526-5539
Author(s):  
Zhi Zhang ◽  
Zhihang Huang ◽  
Hong Yuan
Keyword(s):  
Mesoporous Silica ◽  
Solvent System ◽  
Direct Conversion ◽  
Reaction Yield ◽  
Silica Nanospheres ◽  
Ethyl Levulinate ◽  
System A ◽  
System P ◽  
Mesoporous Silica Nanospheres

A KCC-1/Al–SO3H catalyst with Si/Al = 5 was prepared to directly catalyse the synthesis of ethyl levulinate from cellulose in an ethanol/toluene co-solvent system. A reaction yield of 28.8 mol% was achieved after 6 h at 200 °C.

scholarly journals Effect of Crosslinking Type on the Physical-Chemical Properties and Biocompatibility of Chitosan-Based Electrospun Membranes

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 831
Author(s):  
Andrea Dodero ◽  
Sonia Scarfi ◽  
Serena Mirata ◽  
Alina Sionkowska ◽  
Silvia Vicini ◽  
...  
Keyword(s):  
Chemical Properties ◽  
Biological Properties ◽  
Diglycidyl Ether ◽  
Chemical Crosslinking ◽  
Electrospinning Technique ◽  
Vapour Permeability ◽  
Phosphate Ions ◽  
Physically Crosslinked ◽  
Mechanical Performances ◽  
Average Size

Chitosan nanofibrous membranes are prepared via an electrospinning technique and explored as potential wound healing patches. In particular, the effect of a physical or chemical crosslinking treatment on the mat morphological, mechanical, water-related, and biological properties is deeply evaluated. The use of phosphate ions (i.e., physical crosslinking) allows us to obtain smooth and highly homogenous nanofibers with an average size of 190 nm, whereas the use of ethylene glycol diglycidyl ether (i.e., chemical crosslinking) leads to rougher, partially coalesced, and bigger nanofibers with an average dimension of 270 nm. Additionally, the physically crosslinked mats show enhanced mechanical performances, as well as greater water vapour permeability and hydrophilicity, with respect to the chemically crosslinked ones. Above all, cell adhesion and cytotoxicity experiments demonstrate that the use of phosphate ions as crosslinkers significantly improves the capability of chitosan mats to promote cell viability owing to their higher biocompatibility. Moreover, tuneable drug delivery properties are achieved for the physically crosslinked mats by a simple post-processing impregnation methodology, thereby indicating the possibility to enrich the prepared membranes with unique features. The results prove that the proposed approach may lead to the preparation of cheap, biocompatible, and efficient chitosan-based nanofibers for biomedical and pharmaceutical applications.

scholarly journals Fabrication and Properties of High-Content Keratin/Poly (Ethylene Oxide) Blend Nanofibers Using Two-Step Cross-Linking Process

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Yong Liu ◽  
Xia Yu ◽  
Jia Li ◽  
Jie Fan ◽  
Meng Wang ◽  
...  
Keyword(s):  
Ethylene Oxide ◽  
Average Diameter ◽  
Diglycidyl Ether ◽  
Cross Linking ◽  
Electrospun Fibers ◽  
Hydrophobic Property ◽  
Poly Ethylene Oxide ◽  
Cross Linker ◽  
Poly Ethylene ◽  
Nanofiber Mats

High-content keratin/poly (ethylene oxide) (PEO) (90/10) blend nanofibers were prepared by electrospinning combined with a two-step cross-linking process. The keratin/PEO aqueous solution was firstly mixed with ethylene glycol diglycidyl ether (EGDE) as cross-linker and then electrospun into nanofibers. The resulting nanofibrous mats were cross-linked with EGDE vapor to decrease the solubility of nanofibers in water. The morphologies and properties of electrospun fibers were investigated by SEM, FTIR, TG, XRD, and contact angle testing, respectively. The results showed that the morphologies of nanofibers were uniform at the fiber average diameter of 300 nm with negligible bead defects by adding EGDE to keratin/PEO solutions. The cross-linking results showed that EGDE vapor could improve the hydrophobic property of blended nanofibers. The crystallinity of the keratin/PEO blend nanofiber mat increased from 13.14% for the uncross-linked sample to 21.54% and 35.15% for the first cross-linked and second cross-linked samples, respectively. Free defect nanofiber mats with high keratin content producing from this two-step cross-linking process are particularly promising for tissue engineering and cell-seeded scaffold.

scholarly journals Inhibitory and Facilitatory Cueing Effects: Competition between Exogenous and Endogenous Mechanisms

Vision ◽  
2019 ◽  
Vol 3 (3) ◽  
pp. 40 ◽  
Author(s):  
Alfred Lim ◽  
Vivian Eng ◽  
Caitlyn Osborne ◽  
Steve M. J. Janssen ◽  
Jason Satel
Keyword(s):  
Behavioral Inhibition ◽  
Inhibition Of Return ◽  
Reaction Times ◽  
Target Onset ◽  
Saccadic Reaction Times ◽  
Series Of Experiments ◽  
Endogenous Activity ◽  
Onset Asynchrony ◽  
Delayed Responses

Inhibition of return is characterized by delayed responses to previously attended locations when the cue-target onset asynchrony (CTOA) is long enough. However, when cues are predictive of a target’s location, faster reaction times to cued as compared to uncued targets are normally observed. In this series of experiments investigating saccadic reaction times, we manipulated the cue predictability to 25% (counterpredictive), 50% (nonpredictive), and 75% (predictive) to investigate the interaction between predictive endogenous facilitatory (FCEs) and inhibitory cueing effects (ICEs). Overall, larger ICEs were seen in the counterpredictive condition than in the nonpredictive condition, and no ICE was found in the predictive condition. Based on the hypothesized additivity of FCEs and ICEs, we reasoned that the null ICEs observed in the predictive condition are the result of two opposing mechanisms balancing each other out, and the large ICEs observed with counterpredictive cueing can be attributed to the combination of endogenous facilitation at uncued locations with inhibition at cued locations. Our findings suggest that the endogenous activity contributed by cue predictability can reduce the overall inhibition observed when the mechanisms occur at the same location, or enhance behavioral inhibition when the mechanisms occur at opposite locations.

Ionic Liquid 4-(3-Methyl-1-imidazolio)-1-butanesulfonic Acid Hydrogen Sulfate-catalyzed Synthesis of Phthalazinetrione Derivatives

2012 ◽  
Vol 67 (7) ◽  
pp. 717-724
Author(s):  
Shihua Song ◽  
Xiang Deng ◽  
Zhi Guan ◽  
Yanhong He
Keyword(s):  
Ionic Liquid ◽  
Polyethylene Glycol ◽  
Condensation Reaction ◽  
Reaction Times ◽  
Solvent System ◽  
Environmentally Benign ◽  
Hydrogen Sulfate ◽  
One Pot ◽  
Simple Method ◽  
Peg 600

A simple method for the synthesis of phthalazinetrione derivatives by a one-pot three-component condensation reaction of phthalhydrazide, 1,3-dicarbonyl compounds and aldehydes catalyzed by the ionic liquid 4-(3-methyl-1-imidazolio)-1-butanesulfonic acid hydrogen sulfate ([BSO3HmIm]HSO4) is reported. Good to excellent yields were obtained in short reaction times in the solvent PEG 600 (polyethylene glycol 600) at 120 °C. The strategy proved to be efficient and environmentally benign. The catalyst/solvent system could easily be recovered and reused for at least 5 times without noticeable loss of activity

Design One Kind of Simplified Smart Home Monitor and Controller Based on ARM-Linux System and Information Network to the Public

2012 ◽  
Vol 629 ◽  
pp. 845-847
Author(s):  
Zhan Feng Zhao ◽  
Yun Tao Zhang ◽  
Zhi Quan Zhou ◽  
Hai Yan Yu
Keyword(s):  
Smart Home ◽  
Low Cost ◽  
Text Messages ◽  
Fire Alarm ◽  
The Public ◽  
System A ◽  
Measuring Devices ◽  
Series Of Experiments ◽  
Home Monitor ◽  
And Control

A smart home structure using network (internet, intranet, wireless etc.) is designed and developed to monitor the circumstances and control the appliances in the house when sensors are triggered by some unexpected cases. A good host of low-cost sensors is used to make anti theft alarm, fire alarm, smog alarm etc. And then transmitted these data got from the measuring devices to neutral module. The neutral module is constructed by ARM-S3C6410 hardware and embedded Linux. It can transmit messages to the householders after processed. The householders can visit the web server to make it clear what happened in the house. Moreover, they can control some appliances to make incidences back to normal through the Internet. If the owners are holding mobile phones, the neutral module will transmit text messages to them. In turn, they can also control the appliances by sending some specific instructions. And then the neutral module will give some other messages as feedback. Additionally, visible interphone technology also makes function in this system. A LCD is organized in the neutral module, one person who stays in the house can make a good conversation with others through neutral platform. Finally, a series of experiments are posed to estimate the performance of our solution.

Electron Transport and Photoemission Studies of Amorphous CaAl Thin Films

1994 ◽  
Vol 375 ◽  
Author(s):  
Simon A. Morton ◽  
D. Greig ◽  
C. G. H. Walker ◽  
F. Mayeya ◽  
M. A. Howson ◽  
...  
Keyword(s):  
Electron Transport ◽  
Amorphous Alloys ◽  
The Other ◽  
High Resistivity ◽  
System A ◽  
Fermi Edge ◽  
Electron Transport Properties ◽  
Series Of Experiments ◽  
High Concentrations

AbstractAmorphous alloys of the binary system CaAl are known to have highly unusual electron transport properties with resistivities up to 450μΣcm and a Hall coefficient that deviates from free electron values at Ca concentrations higher than 45 atomic percent. For amorphous CaMg alloys, on the other hand, the resistivity is very much less and this great difference between the two sets of alloys is not fully understood.We report on the correlation of photoemission and transport measurements made on two sets of amorphous CaAl and CaMg alloys prepared by magnetron sputtering in such a way that we could carry out both sets of measurements within the same UHV system. A special feature of the measurements was that the electrical resistivity was also measured in-situ using a specially designed 4-point probe to check for amorphicity and to compare with transport experiments carried out elsewhere.Photoemission studies were carried out in the energy range 15–50 eV with tuneable synchrotron radiation enabling us to examine the Ca 3p-3d photoemission resonance in detail. The main result from the present series of experiments was that whereas in the CaAl alloys the Fermi edge developed a shoulder at high concentrations of Al, this feature was completely absent in CaMg. At the same time the intensity of the Ca 3p-3d photoemission resonance revealed the presence of d-states in both sets of alloys, indicating that the presence of these dstates cannot, by itself, explain the high resistivity of CaAl.

Effects of Processing Parameters on the Morphology and Size of Electrospun PHBV Micro- and Nano-Fibers

2007 ◽  
Vol 334-335 ◽  
pp. 1233-1236 ◽  
Author(s):  
Ho Wang Tong ◽  
Min Wang
Keyword(s):  
Tissue Engineering ◽  
Polymer Solution ◽  
Polymer Concentration ◽  
Solution Concentration ◽  
Processing Parameters ◽  
Electrospun Fibers ◽  
Effective Technique ◽  
Electrospinning Technique ◽  
Needle Diameter ◽  
Short Time

Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) was used to fabricate micro- and nano-fibrous, non-woven mats by electrospinning for potential tissue engineering applications. The morphology and size of electrospun fibers were assessed systematically by varying the processing parameters. It was found that the diameter of the fibers produced generally increased with electrospinning voltage, needle diameter for the polymer jet and polymer solution concentration. Beaded fibers were readily produced at low PHBV concentrations, whereas the needle was blocked within a very short time during electrospinning when the PHBV concentration was too high. At the polymer concentration of 7.5 % w/v, it was shown that beadless PHBV fibers could be generated continuously by adjusting the electrospinning parameters to appropriate values. This study has clearly demonstrated that electrospinning can be an effective technique to produce PHBV micro- and nano-fibers. It has also been shown that composite fibers containing hydroxyapatite (HA) can be produced using the electrospinning technique.

scholarly journals Interactions of Cu-substrates with titanium-alloyed Sn-Zn solders

2006 ◽  
Vol 42 (1) ◽  
pp. 45-56 ◽  
Author(s):  
D. Soares ◽  
J. Barbosa ◽  
C. Vilarinho
Keyword(s):  
Thermal Analyses ◽  
Copper Substrate ◽  
Reaction Times ◽  
Chemical Compositions ◽  
Eutectic Alloys ◽  
Diffusion Couples ◽  
Phase Layer ◽  
Cu Substrates ◽  
Series Of Experiments ◽  
Solid Liquid

The interactions of copper substrate with titanium-alloyed Sn-Zn eutectic solders have been studied. Two series of experiments have been performed. The first one consisted in differential thermal analyses of Sn-Zn nearly eutectic alloys containing from 1.3 to 2.2 wt. % Ti. Diffusion couples consisted of Cu-wires and Sn-Zn-Ti liquid solders, produced at 250 and 275 OC have been prepared in the second series,. The contact times were up to 3600 s. The contact zones have been characterized by optical and scanning electron microscope. Two layers have been found along the interfaces solid/liquid. The first and the second layers are identical, respectively, with ? and ? phases of the Cu-Zn system. No changes of the chemical compositions were detected for the tested temperatures and reaction times. Continuous parabolic growth of the total diffusion zone thickness with the time of diffusion is observed. The growth is due mainly to one the formed layers (? ) while the thickness of the ?-phase layer, stays almost constant for all tested diffusion times and temperatures.

scholarly journals The Sulfuric Acid Solvent System: A Conductometric Investigation of Solutions of 1,1'-Dianthrimide.

1964 ◽  
Vol 18 ◽  
pp. 2400-2401 ◽  
Author(s):  
R. T. Arnesen ◽  
F. J. Langmyhr ◽  
Lloyd M. Jackman ◽  
D. R. Sparrow
Keyword(s):  
Sulfuric Acid ◽  
Solvent System ◽  
System A
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