X-ray diffraction determination of the degree of crystallinity of cellulose using a computer

Goikhman, A.Sh.; Irklei, V. M.; Vavrinyuk, O. S.; Pirogov, V. I.

doi:10.1007/bf00557189

Cited by 15 publications

(8 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The enthalpy values and the temperature of the endothermic peaks were used to determine the degree of crystallinity (D crys ) of the drug in the sugar dispersions. D crys is defined as the ratio of the heat of fusion of the sugar dispersion (ΔH sd ) and the heat of fusion of pure drug (ΔH dr ) multiplied by the fraction of drug (f) in the dispersion (20).…”

Section: Assessment Of Recrystallization In Stored Etx Sugar Dispersimentioning

confidence: 99%

Dissolution Behavior and Thermodynamic Stability of Fused-Sugar Dispersions of a Poorly Water-Soluble Drug

Singh¹,

Chhabra²,

Pathak³

2011

Dissolution Technol.

View full text Add to dashboard Cite

The current research was undertaken to develop and evaluate dissolution profiles of thermodynamically stabilized sugar dispersions of the poorly water-soluble, model drug etoricoxib (ETX). Fused-sugar dispersions were formulated using sorbitol, xylitol, and maltose separately, and the binary systems were stabilized by incorporation of the antiplasticizing agents poloxamer 407 and PVP K30 to obtain ternary and quaternary systems. The sugar dispersions (F1-F12) were subjected to in vitro dissolution studies, and based on model-independent dissolution parameters, ETX-sorbitol binary/ ternary/composite systems were selected for thermodynamic stability study. The aged ETX-sorbitol composite dispersion (SF8) displayed the highest percent dissolution efficiency (%DE 80min of 78.48), the minimum t 50% of 4.45 min, and the least tendency to recrystallize (D cryst of 0.68), confirming maximum amorphization and thermodynamic stability among all the composite dispersions. The SEM photomicrographs reveal complete miscibility of drug in the aged quaternary dispersion SF8, and its diffuse reflectance (DR) spectrum confirms the absence of any chemical change. Conclusively, sorbitol binary systems can be effectively stabilized by incorporation of PVP K30-poloxamer 407 and retain the dissolution characteristics of sugar dispersions upon aging.

show abstract

Section: Assessment Of Recrystallization In Stored Etx Sugar Dispersimentioning

confidence: 99%

Dissolution Behavior and Thermodynamic Stability of Fused-Sugar Dispersions of a Poorly Water-Soluble Drug

Singh¹,

Chhabra²,

Pathak³

2011

Dissolution Technol.

View full text Add to dashboard Cite

show abstract

“…Rather the peak area and peak position changes ( Figure 3 b). This can be attributed to changes in crystallization and microstructure due to the addition of SH [ 63 , 64 ]. The SH decreases the polymer crystallinity, the peak area decreases, from 64% (PCL meshes) to 59% (PCLSH30 meshes).…”

Section: Resultsmentioning

confidence: 99%

“…The applied voltage was 40 kV and the current was 40 mA. The percentage of crystallinity was approximated by dividing the total area of crystalline peaks (2θ: 16–25.8°) by the total area (2θ: 10–49.9°) under the XRD pattern [ 63 , 64 ].…”

Section: Methodsmentioning

confidence: 99%

Preliminary Characterization of a Polycaprolactone-SurgihoneyRO Electrospun Mesh for Skin Tissue Engineering

et al. 2021

View full text Add to dashboard Cite

Skin is a hierarchical and multi-cellular organ exposed to the external environment with a key protective and regulatory role. Wounds caused by disease and trauma can lead to a loss of function, which can be debilitating and even cause death. Accelerating the natural skin healing process and minimizing the risk of infection is a clinical challenge. Electrospinning is a key technology in the development of wound dressings and skin substitutes as it enables extracellular matrix-mimicking fibrous structures and delivery of bioactive materials. Honey is a promising biomaterial for use in skin tissue engineering applications and has antimicrobial properties and potential tissue regenerative properties. This preliminary study investigates a solution electrospun composite nanofibrous mesh based on polycaprolactone and a medical grade honey, SurgihoneyRO. The processing conditions were optimized and assessed by scanning electron microscopy to fabricate meshes with uniform fiber diameters and minimal presence of beads. The chemistry of the composite meshes was examined using Fourier transform infrared spectroscopy and X-ray photon spectroscopy showing incorporation of honey into the polymer matrix. Meshes incorporating honey had lower mechanical properties due to lower polymer content but were more hydrophilic, resulting in an increase in swelling and an accelerated degradation profile. The biocompatibility of the meshes was assessed using human dermal fibroblasts and adipose-derived stem cells, which showed comparable or higher cell metabolic activity and viability for SurgihoneyRO-containing meshes compared to polycaprolactone only meshes. The meshes showed no antibacterial properties in a disk diffusion test due to a lack of hydrogen peroxide production and release. The developed polycaprolactone-honey nanofibrous meshes have potential for use in skin applications.

show abstract

“…For the as‐prepared sample denoted G0, small diffraction peaks attributed to PbSe QDs appear in the XRD spectrum, due to incomplete vitrification in the process of glassmelt quenching, but the QD sizes are too small to be evaluated. A terminology called degree of crystallization is employed to characterize the crystalline phase content in the glass matrix, which operates in finding the ratio of the intensity of scattering by the investigated specimen I exp to the intensity of a standard profile I st of amorphous scattering in the regions and approximates:

c (2 θ) = \frac{I_{\exp} (2 θ)}{I_{st} (2 θ)}

where c (2θ) stands for degree of crystallization, I exp (2θ) for integrated intensity of the XRD diffraction peaks attributed to a certain crystalline substance in a 2θ range, and I st (2θ) for the integrated intensity of the halo ascribed to the amorphous host in the same 2θ range . Using the above equation, the degree of crystallization of sample G0 is evaluated as 1.0%, indicating a small percentage of the PbSe crystalline phase in glass matrix.…”

Section: Resultsmentioning

confidence: 99%

Crystallization Behaviors of PbSe Quantum Dots in Silicate Glasses

Cheng

2013

J. Am. Ceram. Soc.

View full text Add to dashboard Cite

This study, composed of three parts, aims at studying the crystallization behaviors of PbSe quantum dots (QDs) in silicate host glasses. Firstly, due to the importance of the choice of base glass for the QDs' crystallization, the selection of base glass compositions, the glass fragility, and glass formation ability (GFA) are discussed in details, and the results show that the selected glass compositions have an intermediate fragility and accordingly an intermediate glass transition temperature range among a wide variety of inorganic glass systems together with a good GFA/glass stability (GS). Thus, this base glass is suitable as the host glass in which PbSe QDs crystallize. Secondly, the experimental results on PbSe QDs' crystallizations are presented, and the results show that PbSe QDs can precipitate from silicate glasses favorably with no other chemical compounds precipitation, and the optimized temperature for PbSe QDs crystallization is 600°C. Lastly, the classical nucleation theory is used to analyze the PbSe QD crystallization behaviors in host glasses. The steady‐state nucleation rates and the growth rates of PbSe QDs as well as the time–temperature transformation (TTT) curves are calculated. The results indicate that the free surface energy between the PbSe nuclei and the host glass has great influence on the nucleation rates of PbSe QDs, while it has less effect on the growth rates of PbSe QDs; the crystallization behaviors of PbSe QDs with different volume fractions can be described well by the TTT curves while keeping the dimensionless empirical constant, α, unchanged for one certain curve.

show abstract

X-ray diffraction determination of the degree of crystallinity of cellulose using a computer

Cited by 15 publications

References 1 publication

Dissolution Behavior and Thermodynamic Stability of Fused-Sugar Dispersions of a Poorly Water-Soluble Drug

Dissolution Behavior and Thermodynamic Stability of Fused-Sugar Dispersions of a Poorly Water-Soluble Drug

Preliminary Characterization of a Polycaprolactone-SurgihoneyRO Electrospun Mesh for Skin Tissue Engineering

Crystallization Behaviors of PbSe Quantum Dots in Silicate Glasses

Contact Info

Product

Resources

About