scholarly journals Chemical, Microstructural and Morphological Characterisation of Dentine Caries Simulation by pH-Cycling

Minerals ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 5
Author(s):  
Juan Sebastián Zuluaga-Morales ◽  
María Victoria Bolaños-Carmona ◽  
Carolina Cecilia Cifuentes-Jiménez ◽  
Pedro Álvarez-Lloret
Keyword(s):  
Microstructural Properties ◽  
Third Molars ◽  
X Ray Diffraction ◽  
X Ray ◽  
In Vitro Simulation ◽  
Ph Cycling ◽  
Residual Caries ◽  
Microscopy Techniques

In vitro simulation of natural caries is of great importance in dental research for the development of more effective clinical treatments. The pH-cycling (pHc) procedure consists of a dynamic caries process with alternating de-remineralisation periods. The current research aims to evaluate the effects of the pHc procedure on mineral dentine properties in comparison with sound dentine and natural residual caries. For this purpose, dentine slices from human third molars were submitted to cycling periods of 14 and 28 days. The chemical composition, morphological and microstructural properties of the dentine samples were examined by infrared and Raman spectroscopies, X-ray diffraction, and scanning electron microscopy techniques. In addition, the depth of the demineralisation front was evaluated by Masson’s trichrome (MT) staining. The results showed that the pHc procedure led to notable changes in the mineral composition and the crystalline characteristics with respect to sound dentine and some extent to natural caries. The MT results revealed that pHc 28 yields a deeper lesion than pHc 14, simulating potential progression of natural caries. The results of this study provide a better understanding of the mechanisms of demineralisation that could occur in an in vivo environment and provide a standardised substrate similar to natural residual caries.

Effects of dietary alteration of bicarbonate and magnesium on rat bone

1986 ◽  
Vol 250 (2) ◽  
pp. F302-F307 ◽  
Author(s):  
J. M. Burnell ◽  
C. Liu ◽  
A. G. Miller ◽  
E. Teubner
Keyword(s):  
Crystal Structure ◽  
Bone Formation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Growing Rats ◽  
Final Composition ◽  
Rat Bone

To study the effects of bicarbonate and magnesium on bone, mild acidosis and/or hypermagnesemia were produced in growing rats by feeding ammonium chloride and/or magnesium sulfate. Bone composition, quantitative histomorphometry, and mineral x-ray diffraction (XRD) characteristics were measured after 6 wk of treatment. The results demonstrated that both acidosis (decreased HCO3) and hypermagnesemia inhibited periosteal bone formation, and, when combined, results were summative; and the previously observed in vitro role of HCO3- and Mg2+ as inhibitors of crystal growth were confirmed in vivo. XRD measurements demonstrated that decreased plasma HCO3 resulted in larger crystals and increased Mg resulted in smaller crystals. However, the combined XRD effects of acidosis and hypermagnesemia resembled acidosis alone. It is postulated that the final composition and crystal structure of bone are strongly influenced by HCO3- and Mg2+, and the effects are mediated by the combined influence on both osteoblastic bone formation and the growth of hydroxyapatite.

Preparation of N, O-Carboxymethyl Chitosan with Different Substitutional Degree and its Application for Hemostasis

2013 ◽  
Vol 798-799 ◽  
pp. 1061-1066 ◽  
Author(s):  
Yan Wei Zhao ◽  
Lu Liu ◽  
Xiang Han ◽  
Jing Guan
Keyword(s):  
Carboxymethyl Chitosan ◽  
X Ray Diffraction ◽  
Clotting Time ◽  
X Ray ◽  
Angle Measurements ◽  
Contact Angle Measurements ◽  
Ft Ir ◽  
Ubbelohde Viscometer

We prepared N, O-carboxymethyl chitosans (CMCSs) with different substitutional degrees (SDs) to evaluate their effects of hemostasis, and provided experimental basis on biomedical materials. Chloroethanoic acid was used to synthesize CMCSs. The structure were characterized by Fourier transform infrared (FT-IR) and wide-angle X-ray diffraction (WXRD). Potentiometric titration and Ubbelohde viscometer were adopted to determine the SD and intrinsic viscosity of CMCSs. Contact angle measurements were investigated to determine surface wettability. Method of dynamic clotting time and coagulation test in vivo were used to evaluate their effects of hemostasis. SDs of CMCSs were from 50% to 110%. As the SD increased, molecular weight decreased. CMCS powder with SD 63% possessed excellent hemostasis both in vitro and in vivo. CMCS powder owned hemostatic capability prior to CS. CMCS powder with SD 63% (neither too high, nor too low) possessed excellent hemostasis both in vitro and in vivo.

scholarly journals Hydrophilic Sugars for Enhancing Dissolution Rate of Cilostazol: Effect of Wet Co-Processing

2020 ◽  
Vol 27 (1) ◽  
pp. 111-120
Author(s):  
Alaa Yosf Bazeed ◽  
Ahmed Nouh ◽  
Ebtessam Ahmed Essa ◽  
Gamal El Maghraby
Keyword(s):  
Aqueous Solubility ◽  
Submicron Particles ◽  
Drug Dissolution ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Swallowing Difficulties ◽  
Fast Disintegrating Tablets

Background: Cilostazol is an anti-platelets drug with considerable antithrombotic effects in vivo. Therefore, it is widely used by elderly patients. However, it suffers from poor bioavailability due to its low aqueous solubility. The objective of this work was to enhance the dissolution of cilostazol with the aim of formulating fast dissolving tablets for geriatrics and those of swallowing difficulties. Methods: Ethanol-assisted co-grinding of cilostazol with sugar-based excipients was adopted. Sucralose and mannitol were used for this purpose as hydrophilic excipient as well as taste improving agents. The obtained products were investigated regarding differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction, scanning electron microscope (SEM) and in vitro drug dissolution. Fast disintegrating tablets were prepared and evaluated. Results: Thermal behavior of the developed products reflected reduced crystallinity, it also suggested possible existence of new crystalline species with sucralose. Eutexia was also suggested for mannitol mixtures, that was supported by X-ray diffraction data. SEM indicated size reduction with the deposition of the drug as submicron particles over the excipient surface. Co-processing markedly improved cilostazol dissolution compared to unprocessed drug. The optimized formulations were successively formulated into fast disintegrating tablets. Conclusion: This investigation introduced the wet grinding strategy with sugar excipients as a platform for the formulation of easy to use tablets with optimum drug release.

Growth Morphologies, Fragmentation Patterns, and Hardness in Sodium Hydrogen Urate Monohydrate

2015 ◽  
Vol 1721 ◽  
Author(s):  
A. B. Brune ◽  
W.T. Petuskey
Keyword(s):  
Morphological Data ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sodium Hydrogen ◽  
Dislocation Arrays ◽  
Fragmentation Patterns ◽  
Microscopy Techniques ◽  
First Time

ABSTRACTMechanical properties and new morphological data on synthetic sodium hydrogen urate monohydrate are reported and interpreted. Crystals formed in supersaturated aqueous solutions were identified by powder x-ray diffraction. Intact grains and separate needles were examined by several microscopy techniques, some reported here for the first time. The dominant morphology was spherulite-type, comprising tapered, branched blades (needles) radiating out of a common core. The pointed blade tips were truncated by (011) planes, corresponding to hydrogen-bonded planes. Branching was at about a 5° angle or its multiples, suggesting it accommodated by dislocation arrays at the low angle boundaries, as is often seen in twinning. Vicker’s micro-hardness, extrapolated to zero porosity, was 0.90 GPa, which is greater than the hardness measured by nano-indentation. Present results are anticipated to be useful in interpreting the mechanical characteristics of the material crystallized in vivo and its action concerning gout, and affording inferences on the role of the milieu on morphologies, fragmentation, and hardness.

Mechanical, microstructural properties and cell adhesion of Sr/Se-hydroxyapatite/graphene/polycaprolactone nanofibers

2020 ◽  
pp. 089270572091278 ◽  
Author(s):  
Reem Al-Wafi ◽  
SF Mansour ◽  
MK Ahmed
Keyword(s):  
Electron Microscopy ◽  
Tensile Strength ◽  
Microstructural Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nanofibrous Scaffolds ◽  
Transmission Electron ◽  
Fesem Micrographs

Electrospun nanofibrous scaffolds containing co-dopant of Sr/Se into carbonated hydroxyapatite has been synthesized in situ with graphene (G) nanosheets and carried on polycaprolactone at different contributions of G. The powder and the nanofibrous samples were investigated using X-ray diffraction, transmission electron microscopy, and field emission scanning electron microscopy (FESEM). The FESEM micrographs show that the highest content of G (0.2 G) was formed in non-oriented/rough/cracked fibers with diameters around 0.3–0.4 µm at the maximum. The tensile strength of nanofibrous scaffolds was improved with the addition of G nanosheets and the maximum tensile strength of 0.2 G was around 6.39 ± 0.24 MPa, while the minimum cell viability ratio was about 94.4 ± 3.2% for the free G nanofibers. The in vitro attachment of HFB4 cell lines was investigated and it showed that nanofibrous scaffolds have induced cells to be proliferated and spread on the nanofibrous scaffolds’ surface. This behavior of cells growth encourages more investigations for these nanofibrous scaffolds to be promoted for clinical applications.

Apatite Growth on Bioactive Glass in Artificial Saliva

2000 ◽  
Vol 662 ◽  
Author(s):  
Sarah E. Efflandt ◽  
Robert F. Cook ◽  
Lorraine F. Francis
Keyword(s):  
Bioactive Glass ◽  
Artificial Saliva ◽  
Apatite Formation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Time Period ◽  
Surface Morphologies ◽  
Surface Changes

AbstractBioactive glass disks from the MgO-CaO-P2O5-SiO2 system were placed in artificial saliva for time periods varying from 1 to 42 days. Surfaces were then analyzed using scanning electron microscopy (SEM) and x-ray diffraction to investigate surface morphologies and crystallinity. SEM examination exhibited dramatic surface changes as early as 2 d. X-ray results showed crystallinity in the form of apatite at 10 d, which became more developed though 42 d. The bioactive glass in water and non-bioactive glass in artificial saliva were used as controls; both exhibited no evidence of apatite formation on their surfaces through the 42 d time period. This study shows that bioactive glass reacts in artificial saliva to form apatite and that the apatite layer becomes better crystallized over an extended time period. These results give a better understanding of the surface changes and mineralization that occur over time and can be used to interpret results from in vitro and in vivo studies done on bioactive glass in the oral environment.

scholarly journals Bioglass-fibre reinforced hydroxyapatite composites synthesized using spark plasma sintering for bone tissue engineering

2021 ◽  
Vol 15 (3) ◽  
pp. 270-278
Author(s):  
Muhammad Rizwan ◽  
Ali Chandio ◽  
Muhammad Sohail ◽  
Nasir Bashir ◽  
Sumra Yousuf ◽  
...  
Keyword(s):  
Spark Plasma Sintering ◽  
Bone Scaffold ◽  
X Ray Diffraction ◽  
X Ray ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Microscopy Images ◽  
Selection Of

Hydroxyapatite (HA) exhibits several desirable characteristics, but it still lacks osteoinduction, which is a necessary requirement for a bone scaffold. HA-based composites with different amounts of Bioglass? (BG) were prepared using spark plasma sintering (SPS). Careful selection of the SPS parameters avoided undesirable reactions between the calcium phosphate (CaP) and bioglass (BG present in the form of powder and fibres), as confirmed through X-ray diffraction analysis. Scanning electron microscopy images of the composite scaffolds revealed a fibre like appearance of the glassy region. The in vitro bioactivity and biodegradation analyses were performed by immersing the composites in simulated body fluid (SBF) and tris(hydroxymethyl)aminomethane (Tris), respectively. The ability to obtain only the CaP phase and glassy phase with desirable bioactive and biodegradation behaviour, indicated that these SPS scaffolds can be employed as bone scaffolds for clinical trials, after further in vivo analyses.

scholarly journals Two Novel Palbociclib-Resorcinol and Palbociclib-Orcinol Cocrystals with Enhanced Solubility and Dissolution Rate

Pharmaceutics ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 23
Author(s):  
Chenxin Duan ◽  
Wenwen Liu ◽  
Yunwen Tao ◽  
Feifei Liang ◽  
Yanming Chen ◽  
...  
Keyword(s):  
Water Solubility ◽  
Cancer Drug ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Dissolution Rates ◽  
Intrinsic Dissolution ◽  
X Ray ◽  
Enhanced Solubility

Palbociclib (PAL) is an effective anti-breast cancer drug, but its use has been partly restricted due to poor bioavailability (resulting from extremely low water solubility) and serious adverse reactions. In this study, two cocrystals of PAL with resorcinol (RES) or orcinol (ORC) were prepared by evaporation crystallization to enhance their solubility. The cocrystals were characterized by single crystal X-ray diffraction, Hirshfeld surface analysis, powder X-ray diffraction, differential scanning calorimetry, thermogravimetric analysis, Fourier transform infrared and scanning electron microscopy. The intrinsic dissolution rates of the PAL cocrystals were determined in three different dissolution media (pH 1.0, pH 4.5 and pH 6.8), and both cocrystals showed improved dissolution rates at pH 1.0 and pH 6.8 in comparison to the parent drug. In addition, the cocrystals increased the solubility of PAL at pH 6.8 by 2–3 times and showed good stabilities in both the accelerated stability testing and stress testing. The PAL-RES cocrystal also exhibited an improved relative bioavailability (1.24 times) than PAL in vivo pharmacokinetics in rats. Moreover, the in vitro cytotoxicity assay of PAL-RES showed an increased IC50 value for normal cells, suggesting a better biosafety profile than PAL. Co-crystallization may represent a promising strategy for improving the physicochemical properties of PAL with better pharmacokinetics.

scholarly journals Synthesis, Characterization and Antitumour Activity of Metal Complexes of 5-Carboxy-2-Thiouracil

1998 ◽  
Vol 5 (1) ◽  
pp. 35-39 ◽  
Author(s):  
Udai P. Singh ◽  
Sudha Singh ◽  
Sukh Mahendra Singh
Keyword(s):  
Metal Complexes ◽  
Room Temperature ◽  
Magnetic Measurements ◽  
Antitumour Activity ◽  
Tumour Cells ◽  
Sarcoma 180 ◽  
X Ray Diffraction ◽  
X Ray

Metal complexes of 5-carboxy-2-thiouracil with Mn(ll), Co(ll), Ni(ll), Cu(ll), Zn(ll) and Cd(ll) ions were synthesized, characterized, and subjected to a screening system for evaluation of antitumour activity against Sarcoma-180 (S-180) tumour cells. The complexes were characterized by elemental analysis, infrared, electronic spectra, room temperature magnetic measurements and powder X-ray diffraction. The antitumour activity results indicate that some complexes have antitumour activity both in vivo and in vitro against S-180 tumour cells.

scholarly journals Effect of Trimetaphosphate and Fluoride Association on Hydroxyapatite Dissolution and Precipitation In Vitro

2014 ◽  
Vol 25 (6) ◽  
pp. 479-484 ◽  
Author(s):  
Alberto Carlos Botazzo Delbem ◽  
José Antonio Santos Souza ◽  
Ana Carolina Soares Fraga Zaze ◽  
Eliana Mitsue Takeshita ◽  
Kikue Takebayashi Sassaki ◽  
...  
Keyword(s):  
Calcium Fluoride ◽  
Calcium Concentration ◽  
Ph Value ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sodium Trimetaphosphate ◽  
Hydroxyapatite Powder ◽  
Calcium Phosphorus ◽  
Ph Cycling

The present study analyzed the action of sodium trimetaphosphate (TMP) and/or fluoride on hydroxyapatite. Hydroxyapatite powder was suspended in different solutions: deionized water, 500 µg F/mL, 1,100 µg F/mL, 1%TMP, 3%TMP, 500 µg F/mL plus 1%TMP and 500 µg F/mL plus 3%TMP. The pH value of the solutions was reduced to 4.0 and after 30 min, raised to 7.0 (three times). After pH-cycling, the samples were analyzed by X-ray diffraction and infrared spectroscopy. The concentrations of calcium fluoride, fluoride, calcium and phosphorus were also determined. Adding 1% or 3% TMP to the solution containing 500 µg F/mL produced a higher quantity of calcium fluoride compared to samples prepared in a 1,100 µg F/mL solution. Regarding the calcium concentration, samples prepared in solutions of 1,100 µg F/mL and 500 µg F/mL plus TMP were statistically similar and showed higher values. Using solutions of 1,100 µg F/mL and 500 µg F/mL plus TMP resulted in a calcium/phosphorus ratio close to that of hydroxyapatite. It is concluded that the association of TMP and fluoride favored the precipitation of a more stable hydroxyapatite.

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