Tunable photoluminescence properties of microcrystalline cellulose with gradually changing crystallinity and crystal form

2021 ◽  
pp. 2100321
Author(s):  
Jiantang Jiang ◽  
Shijia Lu ◽  
Man Liu ◽  
Chuchu Li ◽  
Yuanchao Zhang ◽  
...  
Keyword(s):  
Microcrystalline Cellulose ◽  
Crystal Form ◽  
Photoluminescence Properties

Dissolution of microcrystalline cellulose and its graft copolymer in ionic liquid of 1-allyl-3-ethylimidazolium chloride

e-Polymers ◽  
2009 ◽  
Vol 9 (1) ◽  
Author(s):  
Liying Guo ◽  
Tiejun Shi ◽  
Zhong Li
Keyword(s):  
Ionic Liquid ◽  
Aqueous Medium ◽  
Graft Copolymer ◽  
Microcrystalline Cellulose ◽  
Monomer Conversion ◽  
Crystal Form ◽  
Effect Of Temperature ◽  
Grafting Efficiency ◽  
C 50 ◽  
Ethylimidazolium Chloride

AbstractThe ionic liquid of 1-allyl-3-ethylimidazolium chloride ([AEIM]Cl) was synthesized and its chemical structure was confirmed. Dissolution of microcrystalline cellulose (MCC) in [AEIM]Cl by microwave heating method was researched. Acrylamide (AM) was grafted onto the dissolved MCC with initiator in [AEIM]Cl and aqueous medium respectively. The effect of temperature, initiator and its dosages on monomer conversion and grafting efficiency was studied. The results showed that [AEIM]Cl was a good solvent for MCC and dissolution rate was the highest (28.8%) when the MCC pretreated with 15% NaOH under the high pressure. Graft copolymer prepared by AM and MCC in [AEIM]Cl had higher monomer conversion and grafting efficiency than in aqueous medium. The best condition for preparing graft copolymer was that potassium persulfate was used as initiator with the dosage of 1g/L under the temperature of 45 °C-50 °C. Spectra of FT-IR had proved that AM was grafted onto MCC. The thermal stability of MCC improved after grafting, and the crystal form was destroyed thoroughly.

The native structure of the eukaryotic ribosome

1983 ◽  
Vol 41 ◽  
pp. 432-433
Author(s):  
R.A. Milligan ◽  
P.N.T. Unwin
Keyword(s):  
Ribosomal Proteins ◽  
Crystal Form ◽  
Native Structure ◽  
X Ray Diffraction ◽  
Eukaryotic Ribosome ◽  
Vitro Analysis ◽  
In Vitro Analysis ◽  
Resolution Structure ◽  
Stable Unit

A detailed understanding of the mechanism of protein synthesis will ultimately depend on knowledge of the native structure of the ribosome. Towards this end we have investigated the low resolution structure of the eukaryotic ribosome embedded in frozen buffer, making use of a system in which the ribosomes crystallize naturally.The ribosomes in the cells of early chicken embryos form crystalline arrays when the embryos are cooled at 4°C. We have developed methods to isolate the stable unit of these arrays, the ribosome tetramer, and have determined conditions for the growth of two-dimensional crystals in vitro, Analysis of the proteins in the crystals by 2-D gel electrophoresis demonstrates the presence of all ribosomal proteins normally found in polysomes. There are in addition, four proteins which may facilitate crystallization. The crystals are built from two oppositely facing P4 layers and the predominant crystal form, accounting for >80% of the crystals, has the tetragonal space group P4212, X-ray diffraction of crystal pellets demonstrates that crystalline order extends to ~ 60Å.

Effects of release modifier on Carvedilol release from Kollidon SR based matrix

2012 ◽  
Vol 1 (8) ◽  
pp. 186 ◽  
Author(s):  
Urmi Das ◽  
Mohammad Salim Hossain
Keyword(s):  
Drug Release ◽  
Sustained Release ◽  
Microcrystalline Cellulose ◽  
Matrix Tablets ◽  
Dissolution Time ◽  
Release Mechanism ◽  
Matrix Tablet ◽  
Weight Variation ◽  
The Matrix ◽  
Tablet Formulations

<p>Sustained release Carvedilol matrix tablets constituting Kollidon SR were developed in this study in an attempt to investigate the effect of release modifiers on the release profile of Carvedilol from matrix. Three matrix tablet formulations were prepared by direct compression of Kollidon SR in combination with release modifier (HPMC and Microcrystalline Cellulose) and magnesium stearate. Tablets containing only Kollidon SR with the active ingredient demonstrated a rapid rate of drug release. Incorporation of HPMC in the matrix tablet prolonged the release of drug but incorporation of Microcrystalline Cellulose showed superimposable release pattern with an initial burst effect as confirmed by mean dissolution time and Higuchi release rate data. After 7 hours of dissolution, Carvedilol release from the matrix systems were 91.42%, 83.41%, from formulation F1 and F2 respectively. Formulation F3 exhibited 100 % release at 4 hours. All the tablet formulations showed acceptable pharmaco-technical properties and complied with the in-house specifications for tablet weight variation, friability, hardness, thickness, and diameter. Prepared tablets also showed sustained release property for carvedilol. The drug release mechanism from the matrix tablets of F1 and F2 was found to be followed by Fickian and F3 by Non-Fickian mechanism.</p><p>DOI: <a href="http://dx.doi.org/10.3329/icpj.v1i8.11095">http://dx.doi.org/10.3329/icpj.v1i8.11095</a></p> <p>International Current Pharmaceutical Journal 2012, 1(8): 186-192</p>

Dimensionally-Controlled Hydrothermal Tm3+-doped Oxidic Nanocrystals and Their Photoluminescence Properties

2010 ◽  
Vol 1247 ◽  
Author(s):  
Rocío Calderón-Villajos ◽  
Carlos Zaldo ◽  
Concepción Cascales
Keyword(s):  
Single Crystals ◽  
Fluorescence Lifetimes ◽  
Photoluminescence Properties ◽  
Reaction Conditions ◽  
Hydrothermal Processes ◽  
Bulk Single Crystals ◽  
Template Free ◽  
Reaction Media

AbstractControlled reaction conditions in simple, template-free hydrothermal processes yield Tm-Lu2O3 and Tm-GdVO4 nanocrystals with well-defined specific morphologies and sizes. In both oxide families, nanocrystals prepared at pH 7 reaction media exhibit photoluminescence in ∼1.95 μm similar to bulk single crystals. For the lowest Tm3+ concentration (0.2 % mol) in GdVO4 measured 3H4 and 3F4 fluorescence lifetimes τ are very near to τrad.

A Possible Basis for Nondestructive Characterization of Ropes of Nylon 6

1997 ◽  
Vol 503 ◽  
Author(s):  
H. Jiang ◽  
M. K. Davis ◽  
R. K. Eby ◽  
P. Arsenovic
Keyword(s):  
Tensile Strength ◽  
Service Life ◽  
Fiber Diameter ◽  
Structural Parameters ◽  
Crystal Form ◽  
Nylon 6 ◽  
Remaining Service Life ◽  
Nondestructive Characterization ◽  
Fractional Content

ABSTRACTPhysical properties and structural parameters have been measured for ropes of nylon 6 as a function of the number of use operations. The fractional content of the α crystal form, sound velocity, birefringence, tensile strength and length all increase systematically and significantly with increasing the number of use operations. The fractional content of the γ crystal form and fiber diameter decrease with use. These trends indicate that the measurement of such properties and structural parameters, especially the length, provide a possible basis for establishing a reliable, rapid, and convenient nondestructive characterization method to predict the remaining service life of nylon 6 ropes.

Optimization of Microcrystalline Cellulose PH 101, Lactose, and Kollidon® K 30 To Obtain Co-Processed Excipient Through Spray Drying

2017 ◽  
Vol 7 (2) ◽  
Author(s):  
Kusuma P. ◽  
Syukri Y ◽  
Sholehuddin F. ◽  
Fazzri N. ◽  
Romdhonah . ◽  
...  
Keyword(s):  
Spray Drying ◽  
Microcrystalline Cellulose ◽  
Chemical Change ◽  
Direct Compression ◽  
Flow Properties ◽  
Scanning Calorimetry ◽  
Compression Process ◽  
Infrared Spectrophotometer ◽  
Physical Mixtures ◽  
Spray Dried

The most efficient tablet processing method is direct compression. For this method, the filler-binder can be made by coprocessing via spray drying method. The purpose of this study was to investigate the effect of spray dried co-processing on microcrystalline cellulose (MCC) PH 101, lactose and Kollidon® K 30 as well as to define the optimum proportions. Spray dried MCC PH 101, lactose, and Kollidon® K 30 were varied in 13 different mixture design proportions to obtain compact, free-flowing filler-binder co-processed excipients (CPE). Compactibility and flow properties became the key parameters to determine the optimum proportions of CPE that would be compared to their physical mixtures. The result showed that the optimum proportion of CPE had better compactibility and flow properties than the physical mixtures. The optimum CPE, consisting of only MCC PH 101 and Kollidon® K 30 without lactose, that were characterized using infrared spectrophotometer, differential scanning calorimetry (DSC), X-ray diffraction (XRD), and scanning electron microscope (SEM) indicated no chemical change therein. Therefore, this study showed that spray dried MCC PH 101, lactose and Kollidon® K 30 could be one of the filler-binder alternatives for direct compression process.

β-Cyclodextrin Polymers on Microcrystalline Cellulose as a Granular Media for Organic Micropollutant Removal from Water

2018 ◽  
Author(s):  
Diego Alzate-Sanchez ◽  
Yuhan Ling ◽  
Chenjun Li ◽  
Benjamin Frank ◽  
Reiner Bleher ◽  
...  
Keyword(s):  
Microcrystalline Cellulose ◽  
Continuous Flow ◽  
Granular Media ◽  
Anaerobic Biodegradation ◽  
Thin Coating ◽  
Micropollutant Removal ◽  
Cyclodextrin Polymers ◽  
Flow Experiments ◽  
Aerobic And Anaerobic ◽  
Cellulose Composite

This manuscript describes cyclodextrin polymers formed as a thin coating on microcrystalline cellulose. The resulting polymer/cellulose composite shows promising performance for removing organic pollutants from water and can be packed into columns for continuous-flow experiments. The polymer/cellulose composite also shows excellent resistance to aerobic and anaerobic biodegradation.

Sign in / Sign up

Export Citation Format

Share Document