MyMedR

Displaying publications 81 - 100 of 378 in total

Abstract:

Sort:

Phytosynthesized metal oxide nanoparticles for pharmaceutical applications

Andra S, Balu SK, Jeevanandham J, Muthalagu M, Vidyavathy M, Chan YS, et al.

Naunyn Schmiedebergs Arch Pharmacol, 2019 07;392(7):755-771.
PMID: 31098696 DOI: 10.1007/s00210-019-01666-7

Developments in nanotechnology field, specifically, metal oxide nanoparticles have attracted the attention of researchers due to their unique sensing, electronic, drug delivery, catalysis, optoelectronics, cosmetics, and space applications. Physicochemical methods are used to fabricate nanosized metal oxides; however, drawbacks such as high cost and toxic chemical involvement prevail. Recent researches focus on synthesizing metal oxide nanoparticles through green chemistry which helps in avoiding the involvement of toxic chemicals in the synthesis process. Bacteria, fungi, and plants are the biological sources that are utilized for the green nanoparticle synthesis. Due to drawbacks such as tedious maintenance and the time needed for the nanoparticle formation, plant extracts are widely used in nanoparticle production. In addition, plants are available all over the world and phytosynthesized nanoparticles show comparatively less toxicity towards mammalian cells. Secondary metabolites including flavonoids, terpenoids, and saponins are present in plant extracts, and these are highly responsible for nanoparticle formation and reduction of toxicity. Hence, this article gives an overview of recent developments in the phytosynthesis of metal oxide nanoparticles and their toxic analysis in various cells and animal models. Also, their possible mechanism in normal and cancer cells, pharmaceutical applications, and their efficiency in disease treatment are also discussed.

Matched MeSH terms: Surface Properties
Fulltext Synthesis and characterization of silver/talc nanocomposites using the wet chemical reduction method

Shameli K, Ahmad MB, Yunus WZ, Ibrahim NA, Darroudi M

Int J Nanomedicine, 2010;5:743-51.
PMID: 21042420 DOI: 10.2147/IJN.S13227

In this study, silver nanoparticles (Ag-NPs) were synthesized using the wet chemical reduction method on the external surface layer of talc mineral as a solid support. Silver nitrate and sodium borohydride were used as the silver precursor and reducing agent in talc. The talc was suspended in aqueous AgNO(3) solution. After the absorption of Ag(+) on the surface, the ions were reduced with NaBH(4). The interlamellar space limits were without many changes (d(s) = 9.34-9.19 A(º)); therefore, Ag-NPs formed on the exterior surface of talc, with d(ave) = 7.60-13.11 nm in diameter. The properties of Ag/talc nanocomposites (Ag/talc-NCs) and the diameters of the Ag-NPs prepared in this way depended on the primary AgNO(3) concentration. The prepared Ag-NPs were characterized by ultraviolet-visible spectroscopy, powder X-ray diffraction, transmission electron microscopy, scanning electron microscopy, and Fourier transform infrared. These Ag/talc-NCs may have potential applications in the chemical and biological industries.

Matched MeSH terms: Surface Properties
Preparation, characterization, and in vivo evaluation of insulin-loaded PLA-PEG microspheres for controlled parenteral drug delivery

Sheshala R, Peh KK, Darwis Y

Drug Dev Ind Pharm, 2009 Nov;35(11):1364-74.
PMID: 19832637 DOI: 10.3109/03639040902939213

AIM: The aim of this study was to prepare insulin-loaded poly(lactic acid)-polyethylene glycol microspheres that could control insulin release at least for 1 week and evaluate their in vivo performance in a streptozotocin-induced diabetic rat model.
METHODS: The microspheres were prepared using a water-in-oil-in-water double emulsion solvent evaporation technique. Different formulation variables influencing the yield, particle size, entrapment efficiency, and in vitro release profiles were investigated. The pharmacokinetic study of optimized formulation was performed with single dose in comparison with multiple dose of Humulin 30/70 as a reference product in streptozotocin-induced diabetic rats.
RESULTS: The optimized formulation of insulin microspheres was nonporous, smooth-surfaced, and spherical in structure under scanning electron microscope with a mean particle size of 3.07 microm and entrapment efficiency of 42.74% of the theoretical amount incorporated. The in vitro insulin release profiles was characterized by a bimodal behavior with an initial burst release because of the insulin adsorbed on the microsphere surface, followed by slower and continuous release corresponding to the insulin entrapped in polymer matrix.
CONCLUSIONS: The optimized formulation and reference were comparable in the extent of absorption. Consequently, these microspheres can be proposed as new controlled parenteral delivery system.

Matched MeSH terms: Surface Properties
Interfacial study of cell adhesion to liquid crystals using widefield surface plasmon resonance microscopy

Soon CF, Khaghani SA, Youseffi M, Nayan N, Saim H, Britland S, et al.

Colloids Surf B Biointerfaces, 2013 Oct 1;110:156-62.
PMID: 23711786 DOI: 10.1016/j.colsurfb.2013.04.012

Widefield surface plasmon resonance (WSPR) microscopy provides high resolution imaging of interfacial interactions. We report the application of the WSPR imaging system in the study of the interaction between keratinocytes and liquid crystals (LC). Imaging of fixed keratinocytes cultured on gold coated surface plasmon substrates functionalized with a thin film of liquid crystals was performed in air using a 1.45NA objective based system. Focal adhesion of the cells adhered to glass and LC were further studied using immunofluorescence staining of the vinculin. The imaging system was also simulated with 2×2 scattering matrix to investigate the optical reflection of the resonant plasmonic wave via the glass/gold/cell and glass/gold/LC/cell layers. WSPR imaging indicated that keratinocytes are less spread and formed distinct topography of cell-liquid crystal couplings when cultured on liquid crystal coated substrates. The simulation indicates that glass/LC shifted the surface plasmon excitation angle to 75.39° as compared to glass/air interface at 44°. The WSPR microcopy reveals that the cells remodelled their topography of adhesion at different interfaces.

Matched MeSH terms: Surface Properties
Development and characterization of lecithin stabilized glibenclamide nanocrystals for enhanced solubility and drug delivery

Kumar BS, Saraswathi R, Kumar KV, Jha SK, Venkates DP, Dhanaraj SA

Drug Deliv, 2014 May;21(3):173-84.
PMID: 24102185 DOI: 10.3109/10717544.2013.840690

Novel LNCs (lipid nanocrystals) were developed with an aim to improve the solubility, stability and targeting efficiency of the model drug glibenclamide (GLB). PEG 20000, Tween 80 and soybean lecithin were used as polymer, surfactant and complexing agent, respectively. GLB nanocrystals (NCs) were prepared by precipitation process and complexed using hot and cold melt technique. The LNCs were evaluated by drug loading, saturation solubility (SL), optical clarity, in vitro dissolution, solid state characterization, in vivo and stability analysis. LNCs exhibited a threefold increase in SL and a higher dissolution rate than GLB. The percentage dissolution efficiency was found to decrease with increase in PEG 20000. The average particle size was in the range of 155-842 nm and zeta potential values tend to increase after complexation. X-ray powder diffractometry and differential scanning calorimetry results proved the crystallinity prevailed in the samples. Spherical shaped particles (<1000 nm) with a lipid coat on the surface were observed in scanning electron microscopy analysis. Fourier transform infrared results proved the absence of interaction between drug and polymer and stability study findings proved that LNCs were stable. In vivo study findings showed a decrease in drug concentration to pancreas in male Wistar rats. It can be concluded that LNCs are could offer enhanced solubility, dissolution rate and stability for poorly water soluble drugs. The targeting efficiency of LNCs was decreased and further membrane permeability studies ought to be carried out.

Matched MeSH terms: Surface Properties
Functionalized glycolipids for potential bioconjugation of vesicles

Tabandeh M, Goh EW, Salman AA, Heidelberg T, Duali Hussen RS

Carbohydr Res, 2018 Nov;469:14-22.
PMID: 30196011 DOI: 10.1016/j.carres.2018.08.016

Two azide-terminated oligoethylene oxide spacered glycolipids have been synthesized, and their assembly behavior has been studied in comparison to the corresponding base surfactants. The results suggest potential of the Guerbet lactoside-based compound for targeted drug delivery, while a coiling of the ethylene oxide linker disfavors the application of the glucoside.

Matched MeSH terms: Surface Properties
Fulltext Effect of sandblasting, silica coating, and erbium: Yttrium-Aluminum-Garnet laser treatment on the shear bond strength of self-adhesive resin cement to alumina ceramics

Caglar I, Ates SM, Boztoprak Y, Aslan YU, Duymus ZY

Niger J Clin Pract, 2018 Aug;21(8):1000-1007.
PMID: 30074001 DOI: 10.4103/njcp.njcp_300_17

Objective: The aim of this study was to investigate the different surface treatments on the bond strength of self-adhesive resin cement to high-strength ceramic.
Materials and Methods: Ninety aluminum oxide ceramic (Turkom-Ceramic Sdn. Bhd., Kuala Lumpur, Malaysia) specimens were produced and divided into nine groups to receive the following surface treatments: control group, no treatment (Group C), sandblasting (Group B), silica coating (Group S), erbium: yttrium-aluminum-garnet (Er:YAG) laser irradiation at 150 mJ 10 Hz (Group L1), Er:YAG laser irradiation at 300 mJ 10 Hz (Group L2), sandblasting + L1 (Group BL1), sandblasting + L2 (Group BL2), silica coating + L1 (Group SL1), and silica coating + L2 (Group SL2). After surface treatments, surface roughness (SR) values were measured and surface topography was evaluated. Resin cement was applied on the specimen surface, and shear bond strength (SBS) tests were performed. Data were statistically analyzed using one-way ANOVA and Tukey's multiple comparisons at a significance level of P < 0.05.
Results: Group S, SL1, and SL2 showed significantly increased SR values compared to the control group (P < 0.05); therefore, no significant differences were found among the SR values of Groups B, BL1, BL2, L1, and L2 and the control group (P > 0.05). Group S showed the highest SBS values, whereas the control group showed the lowest SBS values.
Conclusion: Silica coating is the most effective method for resin bonding of high strength ceramic, but Er:YAG laser application decreased the effectiveness.

Matched MeSH terms: Surface Properties
A statistical approach for modelling the physical process of bacterial attachment to abiotic surfaces

Wang Y, Lee SM, Gentle IR, Dykes GA

Biofouling, 2020 11;36(10):1227-1242.
PMID: 33412938 DOI: 10.1080/08927014.2020.1865934

A statistical approach using a polynomial linear model in combination with a probability distribution model was developed to mathematically represent the process of bacterial attachment and study its mechanism. The linear deterministic model was built based on data from experiments investigating bacterial and substratum surface physico-chemical factors as predictors of attachment. The prediction results were applied to a normal-approximated binomial distribution model to probabilistically predict attachment. The experimental protocol used mixtures of Streptococcus salivarius and Escherichia coli, and mixtures of porous poly(butyl methacrylate-co-ethyl dimethacrylate) and aluminum sec-butoxide coatings, at varying ratios, to allow bacterial attachment to substratum surfaces across a range of physico-chemical properties (including the surface hydrophobicity of bacterial cells and the substratum, the surface charge of the cells and the substratum, the substratum surface roughness and cell size). The model was tested using data from independent experiments. The model indicated that hydrophobic interaction was the most important predictor while reciprocal interactions existed between some of the factors. More importantly, the model established a range for each factor within which the resultant attachment is unpredictable. This model, however, considers bacterial cells as colloidal particles and accounts only for the essential physico-chemical attributes of the bacterial cells and substratum surfaces. It is therefore limited by a lack of consideration of biological and environmental factors. This makes the model applicable only to specific environments and potentially provides a direction to future modelling for different environments.

Matched MeSH terms: Surface Properties
Fulltext Association of some Campylobacter jejuni with Pseudomonas aeruginosa biofilms increases attachment under conditions mimicking those in the environment

Teh AHT, Lee SM, Dykes GA

PLoS One, 2019;14(4):e0215275.
PMID: 30970009 DOI: 10.1371/journal.pone.0215275

Campylobacter jejuni is a microaerophilic bacterial species which is a major food-borne pathogen worldwide. Attachment and biofilm formation have been suggested to contribute to the survival of this fastidious bacteria in the environment. In this study the attachment of three C. jejuni strains (C. jejuni strains 2868 and 2871 isolated from poultry and ATCC 33291) to different abiotic surfaces (stainless steel, glass and polystyrene) alone or with Pseudomonas aeruginosa biofilms on them, in air at 25°C and under static or flow conditions, were investigated using a modified Robbins Device. Bacteria were enumerated and scanning electron microscopy was carried out. The results indicated that both C. jejuni strains isolated from poultry attached better to Pseudomonas aeruginosa biofilms on abiotic surfaces than to the surfaces alone under the different conditions tested. This suggests that biofilms of other bacterial species may passively protect C. jejuni against shear forces and potentially oxygen stress which then contribute to their persistence in environments which are detrimental to them. By contrast the C. jejuni ATCC 33291 strain did not attach differentially to P. aeruginosa biofilms, suggesting that different C. jejuni strains may have alternative strategies for persistence in the environment. This study supports the hypothesis that C. jejuni do not form biofilms per se under conditions they encounter in the environment but simply attach to surfaces or biofilms of other species.

Matched MeSH terms: Surface Properties
Modulation of cell surface hydrophobicity and attachment of bacteria to abiotic surfaces and shrimp by Malaysian herb extracts

Hui YW, Dykes GA

J Food Prot, 2012 Aug;75(8):1507-11.
PMID: 22856578 DOI: 10.4315/0362-028X.JFP-12-062

The use of simple crude water extracts of common herbs to reduce bacterial attachment may be a cost-effective way to control bacterial foodborne pathogens, particularly in developing countries. The ability of water extracts of three common Malaysian herbs (Andrographis paniculata, Eurycoma longifolia, and Garcinia atroviridis) to modulate hydrophobicity and attachment to surfaces of five food-related bacterial strains (Bacillus cereus ATCC 14576, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 10145, Salmonella Enteritidis ATCC 13076, Staphylococcus aureus ATCC 25923) were determined. The bacterial attachment to hydrocarbon assay was used to determine bacterial hydrophobicity. Staining and direct microscopic counts were used to determine attachment of bacteria to glass and stainless steel. Plating on selective media was used to determine attachment of bacteria to shrimp. All extracts were capable of either significantly ( P < 0.05) increasing or decreasing bacterial surface hydrophobicity, depending on the herb extract and bacteria combination. Bacterial attachment to all surfaces was either significantly (P < 0.05) increased or decreased, depending on the herb extract and bacteria combination. Overall, hydrophobicity did not show a significant correlation (P > 0.05) to bacterial attachment. For specific combinations of bacteria, surface material, and plant extract, significant correlations (R > 0.80) between hydrophobicity and attachment were observed. The highest of these was observed for S. aureus attachment to stainless steel and glass after treatment with the E. longifolia extract (R = 0.99, P < 0.01). The crude water herb extracts in this study were shown to have the potential to modulate specific bacterial and surface interactions and may, with further work, be useful for the simple and practical control of foodborne pathogens.

Matched MeSH terms: Surface Properties
Enhanced dispersion of multiwall carbon nanotubes in natural rubber latex nanocomposites by surfactants bearing phenyl groups

Mohamed A, Anas AK, Bakar SA, Ardyani T, Zin WM, Ibrahim S, et al.

J Colloid Interface Sci, 2015 Oct 1;455:179-87.
PMID: 26070188 DOI: 10.1016/j.jcis.2015.05.054

Here is presented a systematic study of the dispersibility of multiwall carbon nanotubes (MWCNTs) in natural rubber latex (NR-latex) assisted by a series of single-, double-, and triple-sulfosuccinate anionic surfactants containing phenyl ring moieties. Optical polarising microscopy, field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and Raman spectroscopy have been performed to obtain the dispersion-level profiles of the MWCNTs in the nanocomposites. Interestingly, a triple-chain, phenyl-containing surfactant, namely sodium 1,5-dioxo-1,5-bis(3-phenylpropoxy)-3-((3-phenylpropoxy)carbonyl) pentane-2-sulfonate (TCPh), has a greater capacity the stabilisation of MWCNTs than a commercially available single-chain sodium dodecylbenzenesulfonate (SDBS) surfactant. TCPh provides significant enhancements in the electrical conductivity of nanocomposites, up to ∼10(-2) S cm(-1), as measured by a four-point probe instrument. These results have allowed compilation of a road map for the design of surfactant architectures capable of providing the homogeneous dispersion of MWCNTs required for the next generation of polymer-carbon-nanotube materials, specifically those used in aerospace technology.

Matched MeSH terms: Surface Properties
Fulltext Enhanced Pharmaceutically Active Compounds Productivity from Streptomyces SUK 25: Optimization, Characterization, Mechanism and Techno-Economic Analysis

Al-Shaibani MM, Radin Mohamed RMS, Zin NM, Al-Gheethi A, Al-Sahari M, El Enshasy HA

Molecules, 2021 Apr 25;26(9).
PMID: 33923072 DOI: 10.3390/molecules26092510

The present research aimed to enhance the pharmaceutically active compounds' (PhACs') productivity from Streptomyces SUK 25 in submerged fermentation using response surface methodology (RSM) as a tool for optimization. Besides, the characteristics and mechanism of PhACs against methicillin-resistant Staphylococcus aureus were determined. Further, the techno-economic analysis of PhACs production was estimated. The independent factors include the following: incubation time, pH, temperature, shaker rotation speed, the concentration of glucose, mannitol, and asparagine, although the responses were the dry weight of crude extracts, minimum inhibitory concentration, and inhibition zone and were determined by RSM. The PhACs were characterized using GC-MS and FTIR, while the mechanism of action was determined using gene ontology extracted from DNA microarray data. The results revealed that the best operating parameters for the dry mass crude extracts production were 8.20 mg/L, the minimum inhibitory concentrations (MIC) value was 8.00 µg/mL, and an inhibition zone of 17.60 mm was determined after 12 days, pH 7, temperature 28 °C, shaker rotation speed 120 rpm, 1 g glucose /L, 3 g mannitol/L, and 0.5 g asparagine/L with R2 coefficient value of 0.70. The GC-MS and FTIR spectra confirmed the presence of 21 PhACs, and several functional groups were detected. The gene ontology revealed that 485 genes were upregulated and nine genes were downregulated. The specific and annual operation cost of the production of PhACs was U.S. Dollar (U.S.D) 48.61 per 100 mg compared to U.S.D 164.3/100 mg of the market price, indicating that it is economically cheaper than that at the market price.

Matched MeSH terms: Surface Properties
Effect of Thermal Cycling on Flexural Properties of Microcrystalline Cellulose-Reinforced Denture Base Acrylic Resins

Rahaman Ali AAA, John J, Mani SA, El-Seedi HR

J Prosthodont, 2020 Aug;29(7):611-616.
PMID: 30637856 DOI: 10.1111/jopr.13018

PURPOSE: To assess the impact of thermal cycling on flexural properties of denture base acrylic resin reinforced with microcrystalline cellulose (MCC) derived from oil palm empty fruit bunch (OPEFB).
MATERIALS AND METHODS: The flexural strength and flexural modulus, following thermal cycling (5000 cycles of 5-55°C) of 3 MCC-reinforced poly methyl methacrylate (PMMA) specimens were compared with the conventional and commercially available high-impact PMMA. The 3 test groups were represented by addition of various weight combinations of MCC and acrylic powders.
RESULTS: All 3 test groups with the addition of MCC demonstrated improved flexural strength and flexural modulus compared to the conventional resin, without and after thermal cycling. The highest mean flexural strength corresponded to the specimens reinforced with 5% MCC followed by 2% MCC.
CONCLUSION: Addition of MCC derived from OPEFB to PMMA may be a viable alternative to the existing, commercially available synthetic reinforced PMMA resins. The potential application of natural fillers in the fabrication of a reinforced denture base resin needs further study.

Matched MeSH terms: Surface Properties
Fulltext Measurements of the stiffness and thickness of the pavement asphalt layer using the enhanced resonance search method

Zakaria NM, Yusoff NI, Hardwiyono S, Nayan KA, El-Shafie A

ScientificWorldJournal, 2014;2014:594797.
PMID: 25276854 DOI: 10.1155/2014/594797

Enhanced resonance search (ERS) is a nondestructive testing method that has been created to evaluate the quality of a pavement by means of a special instrument called the pavement integrity scanner (PiScanner). This technique can be used to assess the thickness of the road pavement structure and the profile of shear wave velocity by using the principle of surface wave and body wave propagation. In this study, the ERS technique was used to determine the actual thickness of the asphaltic pavement surface layer, while the shear wave velocities obtained were used to determine its dynamic elastic modulus. A total of fifteen locations were identified and the results were then compared with the specifications of the Malaysian PWD, MDD UKM, and IKRAM. It was found that the value of the elastic modulus of materials is between 3929 MPa and 17726 MPa. A comparison of the average thickness of the samples with the design thickness of MDD UKM showed a difference of 20 to 60%. Thickness of the asphalt surface layer followed the specifications of Malaysian PWD and MDD UKM, while some of the values of stiffness obtained are higher than the standard.

Matched MeSH terms: Surface Properties
Study on the removal of pesticide in agricultural run off by granular activated carbon

Jusoh A, Hartini WJ, Ali N, Endut A

Bioresour Technol, 2011 May;102(9):5312-8.
PMID: 21232934 DOI: 10.1016/j.biortech.2010.12.074

In this batch study, the adsorption of malathion by using granular activated carbon with different parameters due to the particle size, dosage of carbons, as well as the initial concentration of malathion was investigated. Batch tests were carried out to determine the potential and the effectiveness of granular activated carbon (GAC) in removal of pesticide in agricultural run off. The granular activated carbon; coconut shell and palm shells were used and analyzed as the adsorbent material. The Langmuir and Freundlich adsorption isotherms models were applied to describe the characteristics of adsorption behavior. Equilibrium data fitted well with the Langmuir model and Freundlich model with maximum adsorption capacity of 909.1mg/g. The results indicate that the GAC could be used to effectively adsorb pesticide (malathion) from agricultural runoff.

Matched MeSH terms: Surface Properties
Effect of heparin-surface-modified poly(methyl methacrylate) intraocular lenses on the postoperative inflammation in an Asian population

Lai YK, Fan RF

J Cataract Refract Surg, 1996;22 Suppl 1:830-4.
PMID: 9279680

PURPOSE: To compare the efficacy of heparin-surface-modified (HSM), poly(methyl methacrylate) (PMMA) posterior chamber intraocular lenses (IOLs) with that of unmodified PMMA IOLs in reducing postoperative complications caused by inflammatory reactions after extracapsular cataract extraction in an Asian population.
SETTING: Departments of Ophthalmology, University of Malaya, Kuala Lumpur, Malaysia, and Tan Tock Seng Hospital, Singapore.
METHODS: In a randomized, double-blind study performed at two centers, 51 patients received an HSM PMMA lens and 48, an unmodified PMMA IOL. Cell and pigment deposits were evaluated by slitlamp at 1 to 6 days, 2 to 3 weeks, and 3 to 6 months postoperatively.
RESULTS: Significantly more eyes with unmodified IOLs had inflammatory cell deposits than those with HSM IOLs at 3 to 6 months (P < .001) and 12 to 14 months (P = .018) postoperatively. The HSM group also had significantly fewer cell deposits per patient at these two follow-ups. Significantly more eyes in the non-HSM group had pigment deposits 3 to 6 months after surgery (P = .049). One year postoperatively, about 85% of patients in both groups had a best corrected visual acuity of 0.5 or better.
CONCLUSION: Heparin surface modification significantly reduced the inflammatory response to PMMA IOLs in an Asian population for at least 12 to 14 months.

Matched MeSH terms: Surface Properties
Enhancing the efficiency of polymerase chain reaction using graphene nanoflakes

Abdul Khaliq R, Kafafy R, Salleh HM, Faris WF

Nanotechnology, 2012 Nov 16;23(45):455106.
PMID: 23085573 DOI: 10.1088/0957-4484/23/45/455106

The effect of the recently developed graphene nanoflakes (GNFs) on the polymerase chain reaction (PCR) has been investigated in this paper. The rationale behind the use of GNFs is their unique physical and thermal properties. Experiments show that GNFs can enhance the thermal conductivity of base fluids and results also revealed that GNFs are a potential enhancer of PCR efficiency; moreover, the PCR enhancements are strongly dependent on GNF concentration. It was found that GNFs yield DNA product equivalent to positive control with up to 65% reduction in the PCR cycles. It was also observed that the PCR yield is dependent on the GNF size, wherein the surface area increases and augments thermal conductivity. Computational fluid dynamics (CFD) simulations were performed to analyze the heat transfer through the PCR tube model in the presence and absence of GNFs. The results suggest that the superior thermal conductivity effect of GNFs may be the main cause of the PCR enhancement.

Matched MeSH terms: Surface Properties
Fulltext Degradation effects of dietary solvents on microhardness and inorganic elements of computer-aided design/computer-aided manufacturing dental composites

Munusamy SM, Helen-Ng LC, Farook MS

BMC Oral Health, 2024 Feb 01;24(1):162.
PMID: 38302972 DOI: 10.1186/s12903-024-03905-7

BACKGROUND: Computer-aided design/computer-aided manufacturing (CAD/CAM) dental composites were introduced with superior mechanical properties than conventional dental composites. However, little is known on effects of dietary solvents on microhardness or inorganic elemental composition of CAD/CAM composites.
OBJECTIVES: The objectives of this study were to evaluate the degradation effects of each dietary solvent on the microhardness of the different CAD/CAM dental composites and to observe the degradation effects of dietary solvent on the inorganic elements of the dental composites investigated.
METHODS: Fifty specimens with dimensions 12 mm x 14 mm x 1.5 mm were prepared for direct composite (Filtek Z350 XT [FZ]), indirect composite (Shofu Ceramage [CM]), and three CAD/CAM composites (Lava Ultimate [LU], Cerasmart [CS], and Vita Enamic [VE]). The specimens were randomly divided into 5 groups (n = 10) and conditioned for 1-week at 37°C in the following: air (control), distilled water, 0.02 N citric acid, 0.02 N lactic acid and 50% ethanol-water solution. Subsequently, the specimens were subjected to microhardness test (KHN) using Knoop hardness indenter. Air (control) and representative postconditioning specimens with the lowest mean KHN value for each material were analyzed using energy dispersive X-ray spectroscopy (EDX). Statistical analysis was done using one-way ANOVA and post hoc Bonferroni test at a significance level of p = 0.05.
RESULTS: Mean KHN values ranged from 39.7 ± 2.7 kg/mm2 for FZ conditioned in 50% ethanol-water solution to 79.2 ± 3.4 kg/mm2 for VE conditioned in air (control). With exception to LU, significant differences were observed between materials and dietary solvents for other dental composites investigated. EDX showed stable peaks of the inorganic elements between air (control) and representative postconditioning specimens.
CONCLUSIONS: The microhardness of dental composites was significantly affected by dietary solvents, except for one CAD/CAM composite [LU]. However, no changes were observed in the inorganic elemental composition of dental composites between air (control) and 1-week postconditioning.

Matched MeSH terms: Surface Properties
Fulltext Enhancement of mechanical and thermal properties of polycaprolactone/chitosan blend by calcium carbonate nanoparticles

Abdolmohammadi S, Siyamak S, Ibrahim NA, Yunus WM, Rahman MZ, Azizi S, et al.

Int J Mol Sci, 2012;13(4):4508-22.
PMID: 22605993 DOI: 10.3390/ijms13044508

This study investigates the effects of calcium carbonate (CaCO(3)) nanoparticles on the mechanical and thermal properties and surface morphology of polycaprolactone (PCL)/chitosan nanocomposites. The nanocomposites of PCL/chitosan/CaCO(3) were prepared using a melt blending technique. Transmission electron microscopy (TEM) results indicate the average size of nanoparticles to be approximately 62 nm. Tensile measurement results show an increase in the tensile modulus with CaCO(3) nanoparticle loading. Tensile strength and elongation at break show gradual improvement with the addition of up to 1 wt% of nano-sized CaCO(3). Decreasing performance of these properties is observed for loading of more than 1 wt% of nano-sized CaCO(3). The thermal stability was best enhanced at 1 wt% of CaCO(3) nanoparticle loading. The fractured surface morphology of the PCL/chitosan blend becomes more stretched and homogeneous in PCL/chitosan/CaCO(3) nanocomposite. TEM micrograph displays good dispersion of CaCO(3) at lower nanoparticle loading within the matrix.

Matched MeSH terms: Surface Properties
Evaluation of suitable biodegradable scaffolds for engineered bone tissue

Phang MY, Ng MH, Tan KK, Aminuddin BS, Ruszymah BH, Fauziah O

Med J Malaysia, 2004 May;59 Suppl B:198-9.
PMID: 15468886

Tricalcium phosphate/hydroxyapatite (TCP/HA), hydroxyapatite (HA), chitosan and calcium sulphate (CaSO4) were studied and evaluated for possible bone tissue engineered construct acting as good support for osteogenic cells to proliferate, differentiate, and eventually spread and integrate into the scaffold. Surface morphology visualized by SEM showed that scaffold materials with additional fibrin had more cell densities attached than those without, depicting that the presence of fibrin and collagen fibers were truly a favourite choice of cells to attach. In comparison of various biomaterials used incorporated with fibrin, TCP/HA had the most cluster of cells attached.

Matched MeSH terms: Surface Properties

Filters

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links